阅读说明：本技术 结合材料、纤维体形成装置以及纤维体形成方法 (Bonding material, fiber forming device, and fiber forming method ) 是由 佐合拓己 中沢政彦 上野芳弘 于 2021-07-05 设计创作，主要内容包括：本发明提供一种能够抑制微粉从纤维体脱落的结合材料、纤维体形成装置以及纤维体形成方法。所述结合材料为纤维体形成用的结合材料,包含聚酯和凝集抑制剂,且使纤维和纤维粘结,所述聚酯包含衍生自聚对苯二甲酸乙二醇酯的结构单位、衍生自多元羧酸的结构单位和衍生自多元醇的结构单位,所述多元醇包含三羟甲基丙烷,所述结合材料的动态粘弹性测量中的在150℃下的粘度高于3500泊。(The invention provides a binding material capable of inhibiting fine powder from falling off from a fiber body, a fiber body forming device and a fiber body forming method. The bonding material is a bonding material for forming a fiber body, includes a polyester including a structural unit derived from polyethylene terephthalate, a structural unit derived from a polycarboxylic acid, and a structural unit derived from a polyol including trimethylolpropane, and an aggregation inhibitor, and bonds the fiber and the fiber, and has a viscosity at 150 ℃ higher than 3500 poise in a dynamic viscoelasticity measurement.)

1. A binding material for forming a fiber body, which comprises a polyester and an aggregation inhibitor and binds fibers to each other,

the polyester comprises structural units derived from polyethylene terephthalate, structural units derived from polycarboxylic acids and structural units derived from polyols,

the polyol comprises a trimethylolpropane and a trimethylolpropane,

the viscosity at 150 ℃ in the dynamic viscoelasticity measurement of the binding material is higher than 3500 poise.

2. The bonding material of claim 1,

the glass transition temperature of the bonding material is 65 ℃ or higher.

3. The bonding material of claim 1 or claim 2,

the softening temperature of the bonding material is below 150 ℃.

4. The bonding material of claim 1,

the volume average particle diameter of the binding material is less than 12 μm.

5. A fiber forming apparatus comprising the bonding material according to any one of claims 1 to 4.

6. A method of forming a fiber body, comprising:

a step of mixing fibers and a binder to obtain a mixture; and

a step of heating the mixture to thereby heat the mixture,

the binding material comprises a polyester and an agglutination inhibitor,

the polyester comprises structural units derived from polyethylene terephthalate, structural units derived from polycarboxylic acids and structural units derived from polyols,

the polyol comprises a trimethylolpropane and a trimethylolpropane,

the viscosity at 150 ℃ in the dynamic viscoelasticity measurement of the binding material is higher than 3500 poise.

Technical Field

The present invention relates to a bonding material, a fiber forming apparatus, and a fiber forming method.

Background

As a method for producing a fibrous body such as paper, a method using water at all or almost no amount, which is called a dry method, is desired. For example, patent document 1 discloses a technique of manufacturing a sheet by mixing fibers and a thermoplastic resin in a dry manner and applying heat while the mixture is deposited.

In the mixture in which the fibers and the resin are mixed, the resin is wet-spread in the fibers by heating to a temperature higher than the melting temperature of the resin, and then the resin is solidified by cooling, and the fibers are bonded to become a fibrous body.

However, a mixture in which fibers and a resin are mixed may contain very small particles such as short fibers and fine powders. When a fibrous body is produced using a mixture containing such fine particles, the fine powder may fall off from the fibrous body, and dust may be generated in the apparatus, for example.

Patent document 1: japanese laid-open patent publication No. 2015-092032

Disclosure of Invention

One embodiment of the bonding material according to the present invention is a bonding material for forming a fiber body, which comprises a polyester and an aggregation inhibitor, and bonds fibers to each other, the polyester comprising a structural unit derived from polyethylene terephthalate, a structural unit derived from a polycarboxylic acid, and a structural unit derived from a polyol comprising trimethylolpropane, and which has a viscosity at 150 ℃ higher than 3500 poise in a dynamic viscoelasticity measurement.

One embodiment of the fiber forming apparatus according to the present invention includes the bonding material of the above-described embodiment.

One embodiment of a fiber body forming method according to the present invention includes: a step of mixing fibers and a binder to obtain a mixture; and a step of heating the mixture, the bonding material including a polyester and an agglutination inhibitor, the polyester including a structural unit derived from polyethylene terephthalate, a structural unit derived from a polycarboxylic acid, and a structural unit derived from a polyol, the polyol including trimethylolpropane, the bonding material having a viscosity at 150 ℃ higher than 3500 poise in a dynamic viscoelasticity measurement.

Drawings

Fig. 1 is a schematic view showing a fiber manufacturing apparatus according to an embodiment.

Fig. 2 is a graph showing the temperature dependence of viscosity in the dynamic viscoelasticity measurement of the bonding materials according to the examples and comparative examples.

Detailed Description

Several embodiments of the present invention will be described below. The embodiment described below is a mode for explaining one example of the present invention. The present invention is not limited to the following embodiments, and various modifications may be made without departing from the scope of the present invention. In addition, not all of the structures described below are essential structures of the present invention.

1. Bonding material

The bonding material according to the present embodiment can bond fibers and fibers, and can be preferably used for forming a fibrous body.

1.1. Fiber

The fibers bonded by the binder are not particularly limited, and a wide range of fiber materials can be used. Examples of the fibers include natural fibers (animal fibers and plant fibers), chemical fibers (organic fibers, inorganic fibers, and organic-inorganic composite fibers), more specifically, fibers made of cellulose, silk, wool, cotton, hemp, kenaf, flax, ramie, jute, abaca, sisal, conifer, and broadleaf trees, and the like, and these fibers may be used alone or in a suitable mixture, or regenerated fibers such as regenerated fibers may be used.

Examples of the raw material of the fiber include waste paper, waste cloth, and the like, but at least one of the above fibers may be contained. In addition, various surface treatments may also be performed. The material of the fibers may be pure or may contain various components such as inclusions, additives, and other components.

When the fiber is a single fiber, the average diameter (the maximum length in the direction perpendicular to the longitudinal direction when the cross section is not circular, or the diameter of a circle (equivalent circle diameter) when the circle is assumed to have an area equal to the area of the cross section) of the fiber is 1 μm or more and 1000 μm or less, preferably 2 μm or more and 500 μm or less, and more preferably 3 μm or more and 200 μm or less.

Although the length of the fiber is not particularly limited, the length of the single fiber in the longitudinal direction is 1 μm or more and 5mm or less, preferably 2 μm or more and 3mm or less, and more preferably 3 μm or more and 2mm or less.

The fibers bonded by the bonding material of the present embodiment may also contain short fibers. The length of the short fibers in the longitudinal direction is 1 μm or more and 1mm or less, preferably 2 μm or more and 100 μm or less. Although it is preferable that short fibers are not contained or contained in a smaller amount in the fibers that are the raw material of the fibrous body from the viewpoint of suppressing particles falling off from the fibrous body, the effect of the particle suppression effect of the binder of the present embodiment is more remarkably found when short fibers are contained in the fibers because the binder of the present embodiment easily suppresses the falling off of short fibers from the fibrous body.

1.2. Fibrous body

The fibrous body formed using the bonding material of the present embodiment is not particularly limited as long as it has a structure in which fibers and fibers are bonded by the bonding material. The fibrous body may have a sheet-like shape, a plate-like shape, a web-like shape, a plate-like shape having irregularities, a mass-like shape, a block-like shape, or a combination thereof. Typical examples of the fibrous body include paper and nonwoven fabric. The paper includes, for example, a sheet-like form formed from pulp or waste paper, and includes recording paper, wallpaper, wrapping paper, colored paper, drawing paper, kenter paper, and the like for writing and printing. The non-woven fabric is thicker than paper or low-strength material, and comprises common non-woven fabric, fiberboard, paper towel, kitchen paper, dust absorption paper, filter paper, liquid absorbing material, sound absorbing body, buffer material, cushion, etc.

1.3. Structure of bonding material

The binding material according to the present embodiment includes a polyester and an aggregation inhibitor.

1.3.1. Polyester

The polyester comprises structural units derived from polyethylene terephthalate (PET), structural units derived from polycarboxylic acids, and structural units derived from polyols. In other words, the polyester is a reaction product of mixed raw materials including polyethylene terephthalate (PET), a polycarboxylic acid component, and a polyol component.

1.3.1.1. Structural units derived from polyethylene terephthalate (PET)

The structural units derived from PET in the polyester are introduced into the polyester by the reaction of PET as a raw material contained in the mixed raw material.

As the PET, for example, a PET produced by esterification or transesterification and polycondensation of ethylene glycol, terephthalic acid, dimethyl terephthalate, or the like according to a conventional method can be used.

As the PET, not only unused PET but also recycled PET obtained by recycling (reusing) used PET or PET products can be used. Further, PET using a plant-derived raw material may be used as PET.

As the recycled PET, a used PET may be processed into pellets, or a product such as a film or a bottle or a scrap may be pulverized.

Examples of PET using a plant-derived raw material include PET in which at least one of ethylene glycol and terephthalic acid is a plant-derived PET. Whether or not PET is a material using a plant-derived material can be confirmed, for example, by ASTM D6866 "standard for determining the concentration of carbon of biological origin by radioactive carbon (C14) measurement".

From the viewpoint of environmental protection, PET is preferably recycled PET or PET derived from plant-derived materials. PET using a plant-derived raw material may be used as it is or used as it is.

One kind of PET may be used alone, or two or more kinds may be used simultaneously.

From the viewpoint of controlling the crystallinity of the obtained polyester, the IV value of PET is preferably 0.2 or more and 1.2 or less, more preferably 0.3 or more and 1.1 or less, and further preferably 0.4 or more and 0.6 or less.

The IV value of PET is the intrinsic viscosity and is an indicator of the molecular weight of PET. The IV value of PET can be adjusted by the polycondensation time or the like.

The IV value of PET is determined by mixing phenol and 1, 1, 2, 2-tetrachloroethane in a mass ratio of 1: 1 in 30mL of a mixed solvent in which 0.3g of PET was dissolved, and the obtained solution was measured at 30 ℃ using an Ubbelohde viscometer.

From the viewpoint of controlling the crystallinity of the obtained polyester, the content of PET in the mixed raw materials is preferably 30% by mass or more and 55% by mass or less, more preferably 40% by mass or more and 55% by mass or less, and still more preferably 50% by mass or more and 55% by mass or less, with respect to the total mass of the mixed raw materials.

The proportion of the acid component derived from PET to 100 mol% of the total of the acid components is preferably 40 mol% or more and 75 mol% or less, more preferably 50 mol% or more and 75 mol% or less, and still more preferably 60 mol% or more and 75 mol% or less.

The "acid component" referred to herein is all the acid components contained in the mixed raw materials. The acid component includes an acid component derived from PET (e.g., terephthalic acid, dimethyl terephthalate, etc.), a polycarboxylic acid component, and a monocarboxylic acid described later.

1.3.1.2. Structural units derived from polycarboxylic acids

The structural units derived from the polycarboxylic acid in the polyester are introduced into the polyester by reacting the polycarboxylic acid as a raw material contained in the mixed raw materials.

Examples of the polycarboxylic acid include dicarboxylic acids and tricarboxylic acids. The dicarboxylic acid and the tricarboxylic acid may be used in any one of plural kinds, or may be used appropriately in combination.

Examples of the dicarboxylic acid include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid (for example, a compound in which two carboxyl groups are bonded to the 1, 4-, 1, 5-, 1, 6-, 1, 7-, 2, 6-or 2, 7-positions of naphthalene), an aromatic dicarboxylic acid such as a lower alkyl ester or anhydride thereof, and an aliphatic carboxylic acid such as succinic acid, isodecyl succinic acid, dodecenyl succinic acid, maleic acid, fumaric acid, adipic acid, sebacic acid, furandicarboxylic acid, and a lower alkyl ester or anhydride thereof.

Examples of the lower alkyl esters of terephthalic acid and isophthalic acid include dimethyl terephthalate, dimethyl isophthalate, diethyl terephthalate, diethyl isophthalate, dibutyl terephthalate, and dibutyl isophthalate.

Among them, terephthalic acid, isophthalic acid, and adipic acid are preferable as dicarboxylic acids from the viewpoint of excellent handleability and cost.

Examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, 1, 2, 4-cyclohexanetricarboxylic acid, 2, 5, 7-naphthalenetricarboxylic acid, 1, 2, 4-naphthalenetricarboxylic acid, 1, 2, 5-hexanetricarboxylic acid, 1, 2, 7, 8-octanetetracarboxylic acid, and anhydrides and lower alkyl esters thereof.

Among them, from the viewpoint of excellent workability and cost, as the carboxylic acid of the trivalent or higher valent member, trimellitic acid, trimellitic anhydride, pyromellitic acid, and pyromellitic anhydride are preferable, and trimellitic acid and anhydrides thereof are particularly preferable.

The content of the polycarboxylic acid component in the mixed raw materials is preferably 15% by mass or more and 30% by mass or less, more preferably 15% by mass or more and 25% by mass or less, and still more preferably 15% by mass or more and 20% by mass or less, based on the total mass of the mixed raw materials.

The ratio of the polycarboxylic acid component to 100 mol% of the total acid components is preferably 25 mol% or more and 60 mol% or less, more preferably 25 mol% or more and 50 mol% or less, and still more preferably 25 mol% or more and 40 mol% or less.

1.3.1.3. Structural units derived from polyols

The structural units derived from the polyol in the polyester are introduced into the polyester by the reaction of the polyol as a raw material contained in the mixed raw material.

The polyol contains at least trimethylolpropane, and the polyester contains at least a structural unit derived from trimethylolpropane as the polyol. The content of the structural unit derived from trimethylolpropane in the polyester is 1 part by mole or more and 4 parts by mole or less, preferably 1.5 parts by mole or more and 4 parts by mole or less, relative to 100 parts by mole of the structural unit derived from the acid component.

Therefore, the content of trimethylolpropane in the raw material mixture is 1 part by mole or more, preferably 1 part by mole or more and 5 parts by mole or less, more preferably 1 part by mole or more and 4 parts by mole or less, and most preferably 1.5 parts by mole or more and 3 parts by mole or less, relative to 100 parts by mole of the acid component.

The content of trimethylolpropane in the mixed raw materials is preferably 0.1 mass% or more and 5 mass% or less, more preferably 0.2 mass% or more and 3 mass% or less, and still more preferably 0.4 mass% or more and 2 mass% or less, based on the total mass of the mixed raw materials.

When the content of trimethylolpropane is not less than the lower limit, the reactivity becomes better and the coloration of the polyester can be further suppressed. In addition, the bonding material has improved fiber-to-fiber adhesion in the fiber body. When the content of trimethylolpropane is not more than the above upper limit, the storage stability of the binding material comprising a polyester under a high-temperature environment is further improved. In addition, the generation of gel in the polyester can be further suppressed.

When the content of the structural unit derived from trimethylolpropane in the polyester is above the above-described lower limit value, the coloration of the polyester can be further reduced. In addition, the bonding material comprising polyester improves the fiber-to-fiber adhesion in the fiber body. When the content of the structural unit derived from trimethylolpropane is not more than the above upper limit value, the storage stability of the binding material under a high-temperature environment is further improved.

The polyol preferably further comprises a bisphenol a propylene oxide adduct. That is, the polyester more preferably comprises structural units derived from a bisphenol a propylene oxide adduct.

In the case of including the structural unit derived from a bisphenol a propylene oxide adduct in the polyester, the content thereof is preferably 18 parts by mole or more and 28 parts by mole or less, more preferably 20 parts by mole or more and 27 parts by mole or less, relative to 100 parts by mole of the structural unit derived from the acid component.

Examples of the bisphenol a propylene oxide adduct include polyoxypropylene- (2.0) -2, 2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (2.2) -2, 2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (2.3) -2, 2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (2.4) -2, 2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3.3) -2, 2-bis (4-hydroxyphenyl) propane, and polyoxypropylene (6) -2, 2-bis (4-hydroxyphenyl) propane. In addition, the numerical value in parentheses after the expression "propylene" in the names of the compounds exemplified herein represents the average number of moles of Propylene Oxide (PO) added.

In the case of using a bisphenol A propylene oxide adduct, one species may be used alone, or two or more species may be used simultaneously.

The polyol component may further contain a diol other than the bisphenol a propylene oxide adduct (hereinafter, also referred to as "other diol"), and a trihydric or higher alcohol other than trimethylolpropane (hereinafter, also referred to as "other trihydric or higher alcohol").

As the other dihydric alcohol, for example, examples thereof include aromatic alcohols such as polyoxyethylene- (2.0) -2, 2-bis (4-hydroxyphenyl) propane, polyoxyethylene- (2.2) -2, 2-bis (4-hydroxyphenyl) propane, polyoxyethylene- (2.3) -2, 2-bis (4-hydroxyphenyl) propane and polyoxypropylene (2.2) -2, 2-bis (4-hydroxyphenyl) propane, and aliphatic alcohols such as ethylene glycol, neopentyl glycol, propylene glycol, hexylene glycol, polyethylene glycol, 1, 3-propanediol, 1, 4-butanediol, diethylene glycol, triethylene glycol, 1, 4-cyclohexanedimethanol, D-isosorbide, L-isosorbide, isomannide, tetrahydrofuran glycol and 1, 4-dihydroxy-2-butene. In the names of the compounds exemplified herein, the value in parentheses after the expression "ethylene" indicates the average number of moles of Ethylene Oxide (EO) added, and the value in parentheses after the expression "propylene" indicates the average number of moles of PO added.

One of the other glycols may be used alone, or two or more thereof may be used simultaneously.

Examples of the other trihydric or higher alcohols include sorbitol, 1, 4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1, 2, 4-butanetriol, 1, 2, 5-pentanetriol, glycerol, 2-methyl-1, 2, 3-glycerol, 2-methyl-1, 2, 4-butanetriol, 1, 3, 5-trihydroxybenzene, glycerol, and the like.

Other three or more elementsIs/are as followsOne kind of alcohol may be used alone, or two or more kinds may be used simultaneously.

When the bisphenol a propylene oxide adduct is contained in the raw material mixture, the content thereof is preferably 18 parts by mole or more and 28 parts by mole or less, and more preferably 20 parts by mole or more and 27 parts by mole or less, with respect to 100 parts by mole of the acid component.

The content of the bisphenol a propylene oxide adduct in the raw materials to be mixed is preferably 25% by mass or more and 45% by mass or less, more preferably 25% by mass or more and 40% by mass or less, and still more preferably 25% by mass or more and 35% by mass or less, based on the total mass of the raw materials to be mixed.

1.3.1.4. Other structural units

The polyester may also include structural units derived from other components in addition to the above structural units. That is, the raw material mixture may contain components (other components) other than PET, polycarboxylic acid, and polyol. The structural units derived from other components are introduced into the polyester by reacting the other components as raw materials contained in the mixed raw materials.

Examples of the other components include monocarboxylic acids and monohydric alcohols. Examples of the monocarboxylic acid include: aromatic carboxylic acids having 30 or less carbon atoms such as benzoic acid and p-toluic acid; aliphatic carboxylic acids having 30 or less carbon atoms such as stearic acid and behenic acid; and unsaturated carboxylic acids having one or more double bonds in the molecule, such as cinnamic acid, oleic acid, linoleic acid, and linolenic acid.

Examples of the monohydric alcohol include aromatic alcohols having 30 or less carbon atoms such as benzyl alcohol; and aliphatic alcohols having 30 or less carbon atoms such as oleyl alcohol, lauryl alcohol, cetyl alcohol, stearyl alcohol, and behenyl alcohol.

From the viewpoint of the storage stability of the binder, the glass transition temperature (Tg) of the polyester is preferably 65 ℃ or higher, more preferably 65 ℃ or higher and 85 ℃ or lower, and further preferably 70 ℃ or higher and 80 ℃ or lower. When the glass transition temperature of the polyester is not lower than the lower limit value, the storage stability of the binding material containing the polyester in a high-temperature environment is further improved. When the glass transition temperature of the polyester is not higher than the upper limit value, the adhesion between the fibers and the bonding material is further improved.

The glass transition temperature of the polyester is determined in the following manner. That is, the temperature of the intersection of the base line on the low temperature side of the graph and the tangent line of the endothermic curve in the vicinity of the glass transition temperature when measured at a temperature increase rate of 20 ℃/min was determined using a differential scanning calorimeter, and this was taken as the glass transition temperature.

The softening temperature of the polyester is preferably 100 ℃ or higher and 150 ℃ or lower, and more preferably 100 ℃ or higher and 140 ℃ or lower. When the softening temperature of the polyester is not lower than the lower limit value, the storage stability of the bonding material including the polyester and the produced fiber body in a high-temperature environment is further improved. When the softening temperature of the polyester is not higher than the upper limit value, the adhesiveness of the bonding material containing the polyester is further improved.

The softening temperature of the polyester was determined in the following manner. That is, the temperature at which half of 1.0g of the polyester flows out was measured as the softening temperature by using a fluidity tester through a nozzle of 1 mm. phi. times.10 mm under a load of 20kgf at a constant temperature rise rate of 5 ℃/min.

The Acid Value (AV) of the polyester is preferably 10 to 40mgKOH/g, more preferably 10 to 30 mgKOH/g. When the acid value of the polyester is not less than the above lower limit, the productivity of the polyester is improved. When the acid value of the polyester is not more than the above upper limit value, the moisture resistance of the polyester is improved, and it becomes easy to obtain a bonding material which is hardly affected by the use environment.

The acid value of the polyester is a value in mg of potassium hydroxide required for neutralizing the carboxyl group of 1g sample, and is represented by the unit: mgKOH/g. The acid value of the polyester was determined by dissolving the polyester in benzyl alcohol, and titrating with cresol red as an indicator and a KOH solution defined by 0.02.

Although the molecular weight of the polyester is not particularly limited, the weight average molecular weight (Mw) is in the range of preferably 5000 or more, more preferably 8000 or more to preferably 30000 or less, more preferably 20000 or less from the viewpoint of being able to increase the glass transition temperature and decrease the softening temperature. From the same viewpoint, the number average molecular weight (Mn) is preferably 1000 or more, more preferably 2000 or more, to preferably 10000 or less, more preferably 8000 or less.

Although the molecular weight distribution of the polyester is not particularly limited, the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) measured by Gel Permeation Chromatography (GPC) is in the range of preferably 2 or more, more preferably 2.5 or more, further preferably 3 or more to preferably 30 or less, more preferably 10 or less from the viewpoint of being able to increase the glass transition temperature and decrease the softening temperature.

1.3.1.5. Process for producing polyester

An example of a method for producing a polyester will be described. The method for producing a polyester comprises a step of reacting a raw material mixture comprising the above-mentioned PET, a polycarboxylic acid component and a polyol component, and further comprising other components as necessary.

The step of reacting the mixed raw materials preferably includes at least one of an esterification reaction and a transesterification reaction. Further, it is preferable that the polycondensation reaction is performed after the step of reacting the mixed raw materials.

Specifically, the mixed raw materials and the catalyst are charged into a reaction vessel, heated to raise the temperature, and at least one of the esterification reaction and the transesterification reaction is carried out to remove water or alcohol generated in the reaction. Then, the polycondensation reaction is continued, and at this time, the inside of the reaction apparatus is gradually reduced in pressure, and polycondensation is performed while distilling off the polyol component at a pressure of 150mmHg (20kPa) or less, preferably 15mmHg (2kPa) or less, whereby a polyester can be produced.

The catalyst used in the esterification reaction, the transesterification reaction, and the polycondensation reaction is not particularly limited, and examples thereof include: alkoxy titanium compounds having alkoxy group, titanium carboxylates, titanyl carboxylate salts, titanium chelate compounds and the like; organotin such as dibutyltin oxide; inorganic tin such as tin oxide and 2-ethylhexane tin. In addition to the above, as the catalyst, for example, calcium acetate hydrate, zinc acetate, antimony trioxide, germanium dioxide, or the like can be used.

Examples of the alkoxy titanium compound having an alkoxy group include tetramethoxy titanium, tetraethoxy titanium, tetrapropoxy titanium, tetrabutoxy titanium, tetrapentyloxy titanium, tetraoctyloxy titanium, and the like.

Examples of the titanium carboxylate compound include titanium formate, titanium acetate, titanium propionate, titanium octylate, titanium oxalate, titanium succinate, titanium maleate, titanium adipate, titanium sebacate, titanium hexanetricarboxylate, titanium isooctanetricarboxylate, titanium octatetracarboxylic acid, titanium decanetetracarboxylic acid, titanium benzoate, titanium phthalate, titanium terephthalate, titanium isophthalate, titanium 1, 3-naphthalenedicarboxylate, titanium 4, 4-biphenyldicarboxylate, titanium 2, 5-toluenedicarboxylate, titanium anthracenedicarboxylate, titanium trimellitate, titanium 2, 4, 6-naphthalenetricarboxylate, titanium pyromellitate, titanium 2, 3, 4, 6-naphthalenetetracarboxylate, and the like.

Among them, from the viewpoint of easily obtaining a polyester in which the Total amount of Volatile Organic Compounds (VOC) is reduced (TVOC: Total Volatile Organic Compound), as a catalyst, a titanium-based Compound is preferable, and among them, titanium tetrabutoxide is particularly preferable.

One catalyst may be used alone, or two or more catalysts may be used simultaneously.

The polymerization temperature in the esterification reaction, the transesterification reaction, and the polycondensation reaction is preferably 180 ℃ or more and 280 ℃ or less, and more preferably 200 ℃ or more and 270 ℃ or less. When the polymerization temperature is not lower than the above lower limit, the productivity of the polyester is improved. When the polymerization temperature is not higher than the above upper limit, decomposition of the polyester and by-production of volatile components, which are main causes of odor, can be suppressed, and TVOC can be reduced.

The end point of the polymerization is determined, for example, by the softening temperature of the polyester. For example, the polycondensation reaction may be carried out until the torque of the stirring blade reaches a value indicating a desired softening temperature, and then the polymerization may be terminated. Here, the term "completion of polymerization" means that the stirring of the reaction vessel is stopped, nitrogen is introduced into the reaction vessel, and the inside of the reaction vessel is made to be normal pressure. The polyester obtained after cooling may be pulverized into a desired size as needed.

1.3.2. Agglutination inhibitor

The binding material of the present embodiment includes an agglutination inhibitor. The aggregation inhibitor has a function of making it difficult for particles of a binding material to aggregate together. The aggregation inhibitor is preferably used in a type disposed on (may be coated on) the surface of the polyester particle. The aggregation inhibitor is effective for both the particles of the polyester and the particles of the entire binder.

Examples of such an aggregation inhibitor include fine particles composed of an inorganic substance, and by disposing the fine particles on the surface of the binding material, a very excellent aggregation inhibiting effect can be obtained. The term "agglutination" refers to a state in which objects of the same type or different types are physically present in contact with each other by electrostatic force or van der waals force. In addition, in the case where a plurality of objects (for example, powder) are not aggregated in an aggregate, it does not necessarily mean that all the objects constituting the aggregate are discretely arranged. That is, the non-aggregated state includes a state in which a part of the objects constituting the aggregate is aggregated, and even if the amount of such aggregated objects becomes 10 mass% or less, preferably 5 mass% or less of the entire aggregate, the state is included in the "non-aggregated state" in the aggregate of the plurality of objects. In addition, although the powder is packed in a bag or the like, the particles of the powder are in a state of being in contact with each other, the powder is not aggregated when the particles are in a discrete state by applying an external force to the extent that the particles are not destroyed by mild stirring, dispersion by an air flow, free fall, or the like.

Specific examples of the material of the aggregation inhibitor include silica, fumed silica, titanium oxide, alumina, zinc oxide, cerium oxide, magnesium oxide, zirconium oxide, strontium titanate, barium titanate, and calcium carbonate.

The average particle diameter (number average particle diameter) of the particles of the aggregation inhibitor is not particularly limited, but is preferably 0.001 μm or more and 1 μm or less, and more preferably 0.008 μm or more and 0.6 μm or less. The particles of the aggregation inhibitor are in the range close to so-called nanoparticles, and are generally primary particles because of their small particle size, but they may be higher-order particles due to multiple binding of primary particles. When the particle diameter of the primary particles of the aggregation inhibitor is within the above range, the surface of the binding material can be coated favorably, and a sufficient aggregation inhibiting effect can be imparted.

The above-described effects can be obtained if the content of the aggregation inhibitor in the binding material is 0.1 part by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the binding material, and from the viewpoint of improving the effects and/or suppressing the aggregation inhibitor from falling off from the produced fibrous body, the content is preferably 0.2 part by mass or more and 4 parts by mass or less with respect to 100 parts by mass of the binding material, and more preferably 0.5 part by mass or more and 3 parts by mass or less.

The method of disposing (coating) the aggregation inhibitor on the surface of the binding material is not particularly limited, and the aggregation inhibitor may be blended with the polyester by melt kneading or the like. However, in such a case, since most of the aggregation inhibitor is disposed inside the polyester particles, the aggregation inhibition effect may be reduced with respect to the amount of the aggregation inhibitor added. The aggregation inhibitor is more preferably disposed on the surface of the particles of the binding material as much as possible from the viewpoint of the aggregation inhibition mechanism. Examples of the method of disposing the aggregation inhibitor on the surface of the binding material include coating, and the like.

As a method of disposing the aggregation inhibitor on the surface of the binding material, it is possible to mix only the two and adhere the mixture to the surface by electrostatic force or van der waals force, but a method of charging the powder of the binding material and the aggregation inhibitor into a high-speed rotating mixer and uniformly mixing them is preferable. As such a device, known devices can be used, and examples thereof include an FM stirrer, a henschel stirrer, and a super stirrer.

By such a method, particles of the aggregation inhibitor can be arranged on the surfaces of the particles of the binding material. In the case where the particles of the aggregation inhibitor disposed on the surfaces of the particles are disposed in a state where at least a part of the particles enter or are embedded in the surfaces of the particles of the binding material, the aggregation inhibitor can be made difficult to fall off from the particles of the binding material, and a stable aggregation inhibition effect can be achieved.

1.3.3. Other constructions

The binder may contain a synthetic resin, a colorant, an ultraviolet absorber, a flame retardant, a charge inhibitor, a charge control agent, an organic solvent, a surfactant, a fungicide/antiseptic agent, an antioxidant, an oxygen absorber, and the like as needed. These components may be formulated as one component of the binding material separately from the particles of the binding material.

Examples of the synthetic resin include polyethylene, polypropylene, polyamide, polyacetal, polyethylene terephthalate, polybutylene terephthalate, polyethylene succinate, polybutylene succinate, polyhydroxybutyrate, polylactic acid, polyphenylene sulfide, polyether ether ketone, polyvinyl chloride, polystyrene, polymethyl (meth) acrylate, acrylonitrile-butadiene-styrene resin, polycarbonate, modified polyphenylene ether, polyether sulfone, polyether imide, and polyamide imide. Further, the synthetic resin may be copolymerized or modified, or a styrene resin, an acrylic resin, a styrene-acrylic copolymer resin, an olefin resin, a vinyl chloride resin, a polyester resin, a polyamide resin, a polyurethane resin, a polyvinyl alcohol resin, a vinyl ether resin, an N-vinyl resin, a styrene-butadiene resin, or the like, which is amorphous by copolymerization or modification, may be used.

The binder has a function of binding fibers when used as a raw material of a fibrous body. In addition, the binder has a function of maintaining and improving mechanical strength such as tensile strength and tear strength of the fibrous body and paper strength when used as a raw material of the fibrous body. Whether or not such a binding material is contained in the fiber body can be confirmed by, for example, IR (infrared spectroscopy), NMR (nuclear magnetic resonance), MS (mass spectrometry), various kinds of chromatography, and the like.

1.4. Physical Properties of bonding Material

1.4.1. Viscosity of the bonding Material

The viscosity at 150 ℃ in the dynamic viscoelasticity measurement of the binding material is higher than 3500 poise. The viscosity at 150 ℃ in the dynamic viscoelasticity measurement of the binding material is preferably 4000 poise or more, more preferably 4500 poise or more, and still more preferably 5000 poise or more. By the fact that the viscosity at 150 ℃ in the dynamic viscoelasticity measurement of the bonding material is higher than 3500 poise, it is possible to suppress the case where the bonding material in the vicinity of the surface of the fiber body permeates toward the inside at the time of manufacturing the fiber body, and in this case, the wetting diffusion is easy. This makes it easy for the polyester contained in the binder near the surface of the fibrous body to adhere to the fine powder such as short fibers, thereby suppressing the falling off of the fine powder.

The upper limit of the viscosity at 150 ℃ in the dynamic viscoelasticity measurement of the binding material is 50000 poise or less, preferably 30000 poise or less, more preferably 10000 poise or less. If the upper limit of the viscosity at 150 ℃ in the dynamic viscoelasticity measurement of the bonding material is that degree, the fiber body can be deformed, flowed, and expanded without excessive pressure at the time of molding.

The dynamic viscoelasticity measurement of the binding material can be performed by a conventional method using a dynamic viscoelasticity measuring apparatus. The dynamic visco-elastic device may be, for example, "Rheosol G3000" manufactured by ユーピーエム corporation. The shape of the binding material to be measured is not particularly limited, but is, for example, a pellet, a strip, or a sheet. A jig having a shape suitable for the sample is used for the measurement. As the condition for measurement, for example, heating is performed at a temperature rising rate of 5 ℃/minute from room temperature, for example, in a temperature range from 100 ℃ to 180 ℃, stress having a frequency of 1Hz is applied, and the response thereof is detected. By doing so, data on temperature dependence of viscosity, elastic modulus, and the like can be obtained. By reading out the viscosity at 150 ℃ from the obtained data, the viscosity at 150 ℃ in the dynamic viscoelasticity measurement of the binding material can be known.

1.4.2. Glass transition temperature of the bonding material

In this specification, the glass transition temperature of the binder material is the same as that of the polyester described above. However, when the bonding material contains a plurality of types of polyesters having different glass transition temperatures, the glass transition temperature of the bonding material is set to be the same as the glass transition temperature of the polyester having the lowest glass transition temperature.

The glass transition temperature of the binder is preferably 65 ℃ or higher, more preferably 65 ℃ or higher and 85 ℃ or lower, and further preferably 70 ℃ or higher and 80 ℃ or lower, from the viewpoint of storage stability. When the glass transition temperature of the bonding material is not lower than the lower limit value, the storage stability of the bonding material in a high-temperature environment is further improved. When the glass transition temperature of the binder is not higher than the upper limit value, the fiber-to-fiber adhesiveness by the binder is further improved.

The glass transition temperature of the binder can be determined in the same manner as the glass transition temperature of the polyester.

1.4.3. Softening temperature of bonding material

The softening temperature of the bonding material is preferably 100 ℃ or higher and 150 ℃ or lower, and more preferably 100 ℃ or higher and 140 ℃ or lower. If the softening temperature of the bonding material is in this range, a fibrous body having more excellent mechanical strength can be formed.

The softening temperature of the binder can be determined in the same manner as in the case of the polyester described above.

1.4.4. Average particle size of the binder

The binder is preferably a powder pulverized by the above-mentioned stirrer or the like. The volume-based average particle diameter of the powder particles of the binder is appropriately set in consideration of improvement in mechanical strength of the fibrous body to be formed, and the pulverization and classification operations can be performed at once. The preferred volume average particle diameter d of the binder depends on the amount of the composite in the fiber, and when the amount is 5% by mass or more and 70% by mass or less, the volume average particle diameter d is preferably 1 μm or more and 100 μm or less, and more preferably 3 μm or more and 50 μm or less.

The volume average particle size of the particles of the complex may have a variation (distribution), and when a normal distribution is assumed in a distribution obtained by taking a number of n of 100 or more for each complex, σ may be 0.1 μm or more and 25 μm or less, preferably 0.1 μm or more and 12 μm or less, and more preferably 0.6 μm or more and 6 μm or less. Further, the particle size distribution may be so-called bimodal (bimodal distribution) or multimodal, and thus the strength of the fiber may be improved. When the particle size distribution is multimodal, the average value can be considered in the vicinity of the peak of each distribution, and the average value in this case can be set in the same manner as described for the volume average particle size d.

The outer shape of the particles of the binder is preferably approximately spherical, but is not particularly limited thereto, and may be a disk shape, a spindle shape, an irregular shape, or the like. The volume average particle diameter of the particles of the binding material as a whole can be appropriately set. The volume average particle diameter of the particles of the binder can be adjusted by a classification operation or the like.

The volume average particle diameter of the particles of the binding material can be measured by a particle size distribution measuring apparatus using, for example, a laser diffraction scattering method as a measurement principle. An example of the particle size distribution measuring apparatus is a particle size distribution meter using a dynamic light scattering method as a measurement principle (for example, manufactured by "マイクロトラック UPA" Nissan. K.K.). The frequency of the number-based particle size accumulation can be performed by, for example, a wet flow particle size/shape analyzer (product name "FPIA-2000" manufactured by シスメックス) in which particles are suspended in water.

1.5. Method for producing bonding material

The bonding material of the present embodiment can be produced, for example, by the following steps: a kneading step of melt-kneading the polyester; a pelletizing step of pelletizing the binder; a pulverization step of pulverizing the aggregated binder; and a mixing step of adding an aggregation inhibitor to the pulverized product and mixing the mixture with a high-speed mixer or the like. The aggregation inhibitor may be added in the kneading step. In addition, when the resin composition contains a synthetic resin, a colorant, an ultraviolet absorber, a flame retardant, a charge inhibitor, a charge control agent, an organic solvent, a surfactant, a fungicide/antiseptic agent, an antioxidant, an oxygen absorber, and the like, the addition may be performed in an appropriate step.

The melt-kneading can be carried out using, for example, a kneader, a banbury mixer, a single-shaft extruder, a multi-shaft extruder, a twin-roll, a triple-roll, a continuous kneader, a continuous twin-roll, or the like. The pulverization can be carried out by a pulverizer such as a hammer mill, a pin mill, a chopper, a pulper, a turbo mill, a disc mill, a screen mill, or a jet mill. They can be appropriately combined to obtain pellets or powder of the binder material.

The step of pulverizing may be performed in stages, and first, coarse pulverizing may be performed so that the approximate particle size becomes about 1mm, and then fine pulverizing may be performed so that the particle size becomes the target particle size. In such a case, the exemplified apparatus can be used appropriately in each stage. Further, a freeze grinding method for improving the grinding efficiency of the binder can also be used. The powder of the binding material thus obtained may be used as a binding material, and may contain various particles having various particle diameters. Therefore, classification may be performed using a known classification device as needed.

2. Method for producing fiber body

The method for producing a fibrous body according to the present embodiment includes at least a step of mixing the above-described fibers and the above-described binder to obtain a mixture, and a step of heating the mixture. The obtained fiber body contains the above-mentioned binder and a plurality of fibers, and the plurality of fibers are bonded by the binder.

The step of obtaining the mixture and the step of heating the mixture can be performed in a wide variety of ways. The step of obtaining the mixture can be performed by, for example, mixing the fibers and the binder in the air. The step of heating the mixture can be performed by, for example, heating the mixture with a hot press, a heating roll, or the like, and melting or softening the binder. The temperature in the step of heating the mixture may be set as appropriate so as to be equal to or higher than the softening temperature of the binder.

The method for producing a fibrous body may include, in addition to the step of obtaining the mixture and the step of heating the mixture, an appropriate step such as the step of obtaining the fibers, the step of treating the fibers, the step of molding the mixture, the step of pressurizing the mixture, and the step of molding the fibrous body

When the sheet is produced as a fibrous body, the sheet may include, for example, at least one step selected from the group consisting of: a cutting step of cutting pulp board, waste paper, and the like as raw materials in air; a defibering step of defibering the raw material in air into a fibrous form; a classification step of classifying the impurities and the fibers shortened by the defibration in the air from the defibrated object; a screening step of screening long fibers (long fibers) and an undeployed sheet that has not been adequately defibered from the defibered product in air; a pressurizing step of pressurizing at least one of the deposit and the fibrous body; a cutting step of cutting the fibrous body; and a packaging step of packaging the fibrous body.

In the fibrous body, the mixing ratio of the fibers and the binder can be appropriately adjusted according to the strength, the use, and the like of the fibrous body to be produced. If the fibrous body is a sheet such as copy paper, the ratio of the binder to the fibers is, for example, 5 mass% or more and 70 mass% or less.

According to the method for producing a fibrous body of the present embodiment, since the above-described binder is used, it is possible to suppress the binder in the vicinity of the surface of the fibrous body from penetrating into the inside when the mixture is heated, and the binder is likely to be wet and diffuse in this case. Thus, the polyester contained in the binder in the vicinity of the surface of the fibrous body is easily bonded to the fine powder such as short fibers, and the fibrous body in which the falling-off of the fine powder is suppressed can be produced.

3. Apparatus for producing fibrous body

Hereinafter, a fibrous body production apparatus capable of producing a sheet as a fibrous body will be described.

An example of a fiber manufacturing apparatus according to the present embodiment will be described with reference to the drawings. Fig. 1 is a schematic view of a fiber manufacturing apparatus 100 according to the present embodiment. In the fiber manufacturing apparatus 100, as the fiber body, the sheet S is manufactured in which the above-described fibers that have been defibered and the above-described binder including the polyester and the aggregation inhibitor are heated and the plurality of fibers are bonded by the binder.

As shown in fig. 1, the fibrous body manufacturing apparatus 100 includes, for example, a supply section 10, a rough crushing section 12, a defibration section 20, a screening section 40, a first web forming section 45, a rotating body 49, a mixing section 50, a stacking section 60, a second web forming section 70, a sheet forming section 80, and a cutting section 90.

The supply unit 10 supplies the raw material to the coarse crushing unit 12. The supply unit 10 is, for example, an automatic charging unit for continuously charging the raw material into the coarse crushing unit 12. The raw material supplied by the supply portion 10 is, for example, a substance including the above-described fibers such as waste paper, pulp board, or the like.

The rough crushing section 12 cuts the raw material supplied from the supply section 10 into pieces in a gas such as air. The shape and size of the chips are, for example, chips in a square of several centimeters (cm). In the illustrated example, the coarse crushing portion 12 has a coarse crushing blade 14, and the fed raw material can be cut by the coarse crushing blade 14. As the rough crush portion 12, a chopper is used, for example. The raw material cut by the rough crush portion 12 is received by the hopper 1, and then transferred to the defibration portion 20 through the pipe 2.

The defibering unit 20 defibers the raw material cut by the rough crush unit 12. Here, "to effect defibration" means to disentangle a raw material in which a plurality of fibers are bonded into one fiber. The defibration section 20 also has a function of separating substances such as resin particles, ink, toner, and a sizing agent, which are attached to the raw material, from the fibers.

The substance passing through the defibration section 20 is referred to as "defiberized substance". The "fibrids" may include, in addition to the fibrid fibers to be disentangled, additives such as resin particles, color materials such as ink and toner, a bleed-through preventing agent, and a paper strength enhancing agent, which are separated from the fibers when the fibers are disentangled. The shape of the defibrinated object to be defibrinated is rope-shaped. The unwound fibers may be present in a state not entangled with other unwound fibers, that is, in an independent state, or may be present in a state entangled with other unwound fibers to be in a lump, that is, in a state of forming a lump.

The defibration unit 20 performs defibration in a dry manner. Here, a method of performing a process such as defibration in a gas such as air, not in a liquid, is referred to as a dry method. As the defibration section 20, for example, an impeller mill is used. The defibration section 20 has a function of generating a gas flow that sucks the raw material and discharges the defibrated material. Thus, the defibration section 20 can suck the raw material from the inlet 22 together with the air flow by the air flow generated by itself, perform the defibration process, and convey the defibrated material to the outlet 24. The defibered product having passed through the defibering unit 20 is transferred to the screen unit 40 through the pipe 3. The airflow for conveying the defibered material from the defibering unit 20 to the screening unit 40 may be the airflow generated by the defibering unit 20, or may be the airflow generated by an airflow generating device such as a blower.

The screening section 40 introduces the defibered material, which has been defibered by the defibering section 20, from the introduction port 42, and screens the material according to the length of the fiber. The screening portion 40 includes a drum portion 41 and a housing portion 43, and the housing portion 43 houses the drum portion 41. The drum part 41 is, for example, a sieve. The drum portion 41 has a net and is capable of sieving into fibers or particles of a size smaller than the mesh size of the net, i.e., a first screen passing through the net, and fibers or undeveloped pieces or lumps of a size larger than the mesh size of the net, i.e., a second screen not passing through the net. For example, the first sorted material is conveyed to the stacking unit 60 through the pipe 7. The second screened material is returned from the discharge port 44 to the defibration section 20 via the tube 8. Specifically, the drum unit 41 is a cylindrical screen that is rotationally driven by a motor. As the mesh of the drum portion 41, for example, a wire mesh, a expanded metal formed by stretching a metal plate provided with slits, or a punched metal plate formed with holes in the metal plate by a press or the like is used.

The first web forming section 45 conveys the first screen passed through the screen section 40 into the tube 7. The first web forming section 45 includes a mesh belt 46, a tension roller 47, and a suction mechanism 48.

The suction mechanism 48 is capable of sucking the first screen passing through the openings of the screen section 40 and dispersed in the air onto the mesh belt 46. The first screen is stacked on the web 46 which is moving, thereby forming the web V. The basic structures of the mesh belt 46, the tension roller 47, and the suction mechanism 48 are the same as those of the mesh belt 72, the tension roller 74, and the suction mechanism 76 of the second web forming portion 70 described later.

The web V is formed into a soft and bulky state containing much air by passing through the screening section 40 and the first web forming section 45. The web V stacked on the mesh belt 46 is thrown into the tube 7 and is conveyed to the stacking portion 60.

The rotating body 49 can cut the web V. In the illustrated example, the rotator 49 has a base 49a and a protrusion 49b, and the protrusion 49b protrudes from the base 49 a. The projection 49b has, for example, a plate-like shape. In the illustrated example, four protrusions 49b are provided, and four protrusions 49b are provided at equal intervals. The base portion 49a is rotated in the direction R, so that the projection portion 49b can be rotated about the base portion 49 a. By cutting the web V with the rotating body 49, for example, variation in the amount of the defibrinated material per unit time supplied to the accumulating portion 60 can be reduced.

The rotator 49 is provided in the vicinity of the first web forming portion 45. In the illustrated example, the rotating body 49 is provided in the vicinity of the tension roller 47a located on the downstream side in the path of the web V. The rotating body 49 is provided at a position where the protrusions 49b can contact the web V and do not contact the web 46 where the web V is accumulated. This can prevent the mesh belt 46 from being worn by the projection 49 b. The shortest distance between the projection 49b and the mesh belt 46 is, for example, 0.05mm or more and 0.5mm or less. This is a distance that does not damage the mesh belt 46 and can cut the web sheet V.

The mixing section 50 mixes the first screened material that has passed through the screening section 40, the binding material, and an additive composed of an additive added as needed. The mixing section 50 has: an additive supply unit 52 for supplying an additive; a pipe 54 for transporting the first screen and the additive; a blower 56. In the illustrated example, the additive is supplied from the additive supply portion 52 into the pipe 54 via the hopper 9. The tube 54 is continuous with the tube 7.

In the mixing section 50, the air flow is generated by the blower 56, and the first screen material and the additive can be mixed and conveyed in the pipe 54. The means for mixing the first screen material and the additive is not particularly limited, and may be a means for stirring with a blade rotating at a high speed or a means for utilizing the rotation of the container such as a V-type stirrer.

As the additive supply portion 52, a screw feeder as shown in fig. 1, a disk feeder not shown, or the like is used. The additive supplied from the additive supply part 52 includes the above-described binder. At the point in time when the bonding material is supplied, the plurality of fibers are not bonded. The bonding material melts when passing through the sheet forming portion 80, and bonds the plurality of fibers.

The additive supplied from the additive supply portion 52 may contain, in addition to the binder, a colorant for coloring the fibers, an aggregation inhibitor for inhibiting aggregation of the fibers and aggregation of the binder, and a flame retardant for making the fibers and the like difficult to burn, depending on the type of the sheet to be manufactured. The mixture having passed through the mixing section 50 is transferred to the stacking section 60 via the pipe 54.

The accumulation section 60 introduces the mixture having passed through the mixing section 50 from the introduction port 62, unwinds the entangled object, and lowers the object while dispersing the object in the air. This enables the accumulation section 60 to accumulate the mixture on the second web forming section 70 with good uniformity.

The stacking portion 60 includes a roller portion 61 and a housing portion 63, and the housing portion 63 houses the roller portion 61. A cylindrical screen that rotates is used as the drum part 61. The drum part 61 has a net, and drops down the fibers and particles of the binding material contained in the mixture passing through the mixing part 50 and having a size smaller than the mesh size of the net. The structure of the drum portion 61 is, for example, the same as that of the drum portion 41.

The "screen" of the drum unit 61 may not have a function of screening a specific object. That is, the "sieve" used as the drum part 61 is a member provided with a net, and the drum part 61 may drop the whole of the mixture introduced into the drum part 61.

The second web forming portion 70 accumulates the pass-through passing through the accumulation portion 60 and forms the web W. The second web forming section 70 has, for example, a mesh belt 72, a tension roller 74, and a suction mechanism 76.

The mesh belt 72 is moved to deposit the objects passing through the openings of the deposit unit 60. The mesh belt 72 is tensioned by a tension roller 74, and becomes a structure through which it is difficult to pass a passing object but air passes. The mesh belt 72 is rotated and moved by the tension roller 74. The web W is formed on the mesh belt 72 by continuously dropping and accumulating the passing objects that have passed through the accumulating portion 60 while the mesh belt 72 is continuously moving.

The suction mechanism 76 is provided at the lower side of the mesh belt 72. The suction mechanism 76 is capable of generating a downward-directed airflow. The mixture dispersed in the air by the accumulation section 60 can be sucked onto the mesh belt 72 by the suction mechanism 76. This can increase the discharge speed from the stacking unit 60. Further, the suction mechanism 76 can form a downward airflow in the falling path of the mixture, thereby preventing the fluff and the additive from being entangled during the falling process.

As described above, the web W in a soft and bulky state containing a large amount of air is formed by passing through the stacking portion 60 and the second web forming portion 70. The web W stacked on the mesh belt 72 is conveyed toward the sheet forming portion 80.

In the illustrated example, a humidity conditioning unit 78 for conditioning the web W is provided. The humidifying section 78 can adjust the amount ratio of the web W and water by adding water or water vapor to the web W.

The sheet forming section 80 presses and heats the web W stacked on the mesh belt 72 to form the sheet S. In the sheet forming section 80, the mixture of the defibrates and the additives mixed in the web W is heated, whereby the plurality of fibers in the mixture can be bonded to each other via the additives.

The sheet forming section 80 includes a pressing section 82 that presses the web W, and a heating section 84 that heats the web W pressed by the pressing section 82. The pressing section 82 is constituted by a pair of calender rolls 85, and applies pressure to the web W. The web W becomes smaller in thickness due to being pressed, and the bulk density of the web W increases. As the heating section 84, for example, a heating roller, a hot press molding machine, a hot plate, a hot air blower, an infrared heater, and a flash lamp fixing device are used. In the illustrated example, the heating unit 84 includes a pair of heating rollers 86. By configuring the heating section 84 as the heating roller 86, the sheet S can be formed while continuously conveying the web W, as compared with the case where the heating section 84 is configured as a plate-shaped pressing device. The calender roll 85 and the heating roll 86 are disposed such that their rotation axes are parallel to each other, for example. Here, the calender roll 85 can apply a higher pressure to the web W than the pressure applied to the web W by the heating roll 86. The number of the calender rolls 85 and the heating roll 86 is not particularly limited.

The cutting section 90 cuts the sheet S molded by the sheet forming section 80. In the illustrated example, the cutting section 90 has a first cutting section 92 that cuts the sheet S in a direction intersecting the conveying direction of the sheet S, and a second cutting section 94 that cuts the sheet S in a direction parallel to the conveying direction. The second cutting unit 94 cuts the sheet S that has passed through the first cutting unit 92, for example.

In this way, a single sheet S of a predetermined size is molded. The cut sheet S is discharged to the discharge section 96.

According to the apparatus for producing a fibrous body of the present embodiment, since the above-described binder is used, the generation of particles such as fiber powder can be suppressed by the binder. This can suppress accumulation of particles in the apparatus to be small, for example.

4. Examples and comparative examples

The present invention will be further described below by way of examples and comparative examples, but the present invention is not limited to the following examples.

4.1. Preparation of evaluation sample

4.1.1. Example 1

The bonding material of example 1 was obtained in the following manner.

4.1.1.(1) Synthesis of polyesters

To 100 parts by mole of the acid component, 72 parts by mole of polyethylene terephthalate (PET), 27.9 parts by mole of terephthalic acid, 0.1 parts by mole of adipic acid, 24 parts by mole of polyoxypropylene- (2.3) -2, 2-bis (4-hydroxyphenyl) propane, 2 parts by mole of trimethylolpropane, and 500ppm of titanium tetrabutoxide as a catalyst with respect to the acid component were charged into a reaction vessel equipped with a distillation column. In addition, with respect to PET, a unit composed of 1 mole of terephthalic acid and 1 mole of ethylene glycol was counted as 1 mole of PET, and with respect to 1 mole of PET, terephthalic acid derived from PET was counted as 1 mole of acid component and ethylene glycol derived from PET was counted as 1 mole of alcohol component, respectively. Then, the rotation speed of the stirring blade in the reaction vessel was kept at 200rpm, the temperature was raised to heat the reaction system to 265 ℃. At the point when no more water distilled off from the reaction system, the esterification reaction was completed.

Then, the temperature in the reaction system was lowered and maintained at 255 ℃, the pressure in the reaction vessel was reduced for about 20 minutes to 133Pa in vacuum, and the polycondensation reaction was carried out while distilling the polyol out of the reaction system. The viscosity of the reaction system increases with the reaction, and the degree of vacuum increases with the increase in viscosity, and the polycondensation reaction proceeds until the torque of the stirring blade reaches a value indicating a desired softening temperature. Then, at a time point indicating a predetermined torque, the stirring was stopped, the reaction system was returned to normal pressure, and the reaction mixture was taken out from the reaction vessel by pressurization with nitrogen to obtain a polyester. After the obtained polyester was cooled to room temperature and solidified, coarse pulverization was carried out by a coarse crusher (ロートプレックス/Rotoplex).

4.1.1.(2) sizing of polyesters

The coarsely pulverized polyester was pulverized into particles having a diameter of 1mm or less by a hammer mill (product name "ラボミル LM-5" manufactured by ダルトン Co., Ltd.). Further, the pulverized particles were pulverized by a jet mill (product name "PJM-80 SP" manufactured by japan ニューマチック corporation) to obtain particles having a maximum particle diameter of 40 μm or less. The particles were classified by means of an air classifier (product name: MDS-3, manufactured by Japan ニューマチック Co.) so that the volume average particle diameter became 8 μm.

4.1.1.(3) coating of aggregation inhibitor onto particles of polyester

100 parts by weight of uncoated polyester particles and 1 part by weight of fumed silica (product name "AEROSIL R972" from Japan アエロジル) as an aggregation inhibitor were charged into a mixer (product name "ワーリングブレンダー 7012" from Waring) and mixed at 15600rpm for 60 seconds. The resin particles subjected to this treatment were sorted in a glass container and left to stand at room temperature for 24 hours, and no resin aggregation and blocking (blocking) were observed, and the state of the fluid powder particles was maintained. This confirmed that the aggregation inhibitor was applied and the state of non-aggregation was maintained. In addition, the Tg of the bonding material obtained was 65 ℃.

4.1.1.(4) production of sheet (fibrous body) of example 1

As a raw material for the sheet, i.e., fiber, powdered cellulose (manufactured by japan kogaku corporation, trade name "KC フロック W50-S") was used. 20 parts by weight of the fiber and 5 parts by weight of the binder obtained by the production of the binder were put into a mixer (product of Waring Co., trade name: ワーリングブレンダー 7012) and mixed at a revolution number of 3100rpm for 7 seconds to obtain a mixture of the fiber and the binder.

40 parts by weight of the obtained mixture was put into a 200 mm-diameter sieve having a mesh size of 0.6mm, and was deposited on a fluororesin-coated aluminum disk (product of Sumitomo electronics ファインポリマー, trade name: スミフロンコートアルミ) having a diameter of 250mm (plate thickness: 1mm) by using an electric sieve shaker (product of レッチェ, trade name: AS-200). An aluminum disk coated with a fluororesin of the same diameter was further placed on the stacked mixed material, and the pressure applied to the sheet was increased to 1MPa by a press.

The pressurized mixture was heated at 150 ℃ for 15 seconds by placing the mixture on a hot press with an aluminum plate therebetween. The pressure was released and left at room temperature and cooled to room temperature. The mixture was peeled off from the aluminum plate, thereby obtaining a sheet. The heating and pressing method can form a state in which the bonding material is sufficiently impregnated between the celluloses. Therefore, the formed sheet may exhibit tensile strength and rigidity which are inherent. The thickness of the obtained flakes was about 130 μm.

4.1.2. Example 2

Production of the binder and production of the sheet were carried out in the same manner as in example 1, except that the volume average particle size of the binder was set to 12 μm.

4.1.3. Example 3

Production of the binder and production of the sheet were carried out in the same manner as in example 1, except that the volume average particle size of the binder was 20 μm.

4.1.4. Comparative example 1

Instead of the polyesters used in examples 1 to 3, polyester "バイロン 220" manufactured by Toyo Boseki K.K., a commercially available resin (Tg: 54 ℃) was used without performing polyester synthesis.

Sizing and coating of aggregation inhibitor the binder of comparative example 1 having a volume average particle diameter of 12 μm was obtained in the same manner as in example 1. The sheet was produced in the same manner as in example 1.

4.1.5. Comparative example 2

The polyester was synthesized as follows. A5L stainless steel flask equipped with a stirrer, a nitrogen inlet, and a thermometer and having four ports was charged with 25.5 moles of ethylene glycol, 25.5 moles of 1, 2-propanediol, 47.2 moles of terephthalic acid, and 1.8 moles of trimellitic anhydride at a ratio, heated and melted at 120 ℃ and then isopropyl titanate was added. After heating to 240 ℃ under a nitrogen stream and reacting for 3 hours, the reaction was carried out at 220 ℃ under 5kPa for 3 hours. After the obtained polyester was cooled to room temperature and solidified, it was roughly pulverized by a rough pulverizer.

Sizing and coating of aggregation inhibitor the binder of comparative example 2 having a volume average particle diameter of 12 μm was obtained in the same manner as in example 1. The sheet was produced in the same manner as in example 1. In addition, the Tg of the bonding material obtained was 65 ℃.

4.2. Evaluation method

4.2.1. Measurement of glass transition temperature (Tg)

The measurement was carried out using a Differential Scanning Calorimeter (DSC) (product name "Thermo Plus EVO2DSC 8231" manufactured by リガク Co.). 10mg of a sample was weighed in an aluminum pan, and 10mg of Al was weighed₂O₃The powder was used as a reference sample. Heating to 150 deg.C, cooling to 0 deg.C, and heating to 150 deg.C at a heating rate of 20 deg.C/min to obtain the extension line and step-like change of base line of DSC curve at low temperature sideThe glass transition temperature (Tg) is defined as the intersection of tangents drawn at the point where the slope of the curve of the transition portion is maximum. The results measured for the bonding materials of the examples are reported in table 1.

4.2.2. Measurement of softening temperature

A flowability tester (manufactured by shimadzu corporation, trade name "CFT-500D") was used. While heating a 1.0g sample at a temperature rise rate of 5 ℃/min, a load of 20kgf was applied, and the sample was extruded from a nozzle having a diameter of 1mm and a length of 1 mm. The temperature profile was plotted, and the temperature at which half of the sample flowed out was taken as the softening temperature. The results measured for the bonding materials of the examples are set forth in table 1.

4.2.3. Dynamic viscoelasticity measurement of a binding material

In the dynamic viscoelasticity measurement of the bonding material, Rheosol G3000 from ユービーエム was used. 0.7g of the binder was charged into a cylinder having an inner diameter of 20mm to 1.5ton/cm²The mixture was pressed to form pellets. The measurement was performed at a measurement frequency of 1Hz in a temperature range from 100 ℃ to 180 ℃ while heating at a temperature rise of 5 ℃/min using parallel plates in the chuck. The values of the viscosity at 150 ℃ for the bonding materials of the respective examples are described in table 1. Table 2 shows the values of viscosity at each temperature. Fig. 2 shows a graph showing the temperature dependence of the viscosity. In addition, since the materials of examples 1 to 3 are the same, the results of example 1 are described.

4.2.4. Measurement of amount of paper powder generated from sheet (fibrous body)

To each of the produced sheets, an adhesive tape was cut out into a size of 20mm × 20mm by pasting coated adhesive tape 605#50 (produced by manufacturing company) as a low-viscosity adhesive tape to each of the produced sheets. The tape was removed and observed using a microscope VHX-5000 manufactured by キーエンス, and the amount of paper powder transferred to the tape was measured. The number of paper powders transferred to a 20mm × 20mm adhesive tape was 10 or less as "a", 11 or more and 50 or less as "B", and 51 or more as "C", and the evaluation results are shown in table 1.

4.2.5. Measurement of tensile Strength

The sheet obtained in each example was subjected to a tensile test based on JIS P8113. The sheet used was a sheet manufactured by a hot press. After cutting out an experimental piece (total length 180mm) from a sheet, the sheet was left on a tensile tester (manufactured by shimadzu corporation, trade name "AGS-X") and a tensile test was performed at an elongation rate of 20 mm/min. The breaking stress (MPa) of the test piece was determined as the tensile strength from the maximum load until the test piece broke. The tensile test was carried out in an environment of room temperature 23 ℃ and humidity 50% in accordance with JIS P8111. The tensile strength was determined based on a tensile strength of 15MPa as a practical tensile strength. The results are shown in table 1, with "a" for a pressure of 15MPa or more and "B" for a pressure less than 15 MPa.

4.2.6. Storage stability of bonding material in storage container

With respect to the storage stability of the binding material in the storage container, a storage experiment was performed in an environment of 50 ℃ with the binding material placed in the storage container, and a case where no change in the flowability of the powder was observed compared with the initial state was referred to as "a", and a case where a change in the flowability was observed by visual observation was referred to as "B", and the results are shown in table 1.

TABLE 1

TABLE 2

TABLE 2

4.3. Evaluation results

When the amounts of paper dust generated from the flakes of example 2 and comparative example 1, in which the volume average particle size was 12 μm, were compared, the amount of paper dust generated was small in example 2. In addition, the amount of paper dust generated from the sheet was smaller in any of the examples as compared with comparative example 2 having the same Tg. This result is considered to be influenced by the viscosity of the bonding material when melted.

The viscosity at 150 ℃ of the examples was higher than that of the comparative examples. This is considered to be because, when the sheet is produced, when the sheet is heated at 150 ℃, the sheet is inhibited from permeating in the thickness direction of the sheet when the viscosity is high, and the sheet is moistened and diffused by the pressure. Thus, it is considered that the binding material diffuses in the vicinity of the surface of the sheet, and the falling-off of the short fibers can be suppressed. However, since the diffusion of the bonding material becomes worse even when the viscosity is excessively high, it is considered that the range as the viscosity is preferably a range of more than 3500 poise and less than 50000 poise.

In addition, in the case of comparing examples 1 to 3, the smaller the volume average particle diameter, the smaller the amount of paper powder. In example 3 having a volume average particle diameter of 20 μm, the tensile strength of the sheet did not satisfy the practical standard. This is considered to be because the number of particles in the same weight is smaller when the particle diameter is larger than when the particle diameter is smaller, and the number of bonding points between the bonding material and the fibers is reduced, because the sheet is molded at a weight ratio.

In examples 1 to 3 and comparative example 2 having a Tg of 65 ℃ or higher, no change was observed in the fluidity of the binder in the storage test at 50 ℃ in the storage container. On the other hand, in comparative example 1 having a Tg of 54 ℃, agglomeration of the binder was observed.

The present invention includes substantially the same structure as that described in the embodiments, for example, a structure having the same function, method, and result, or a structure having the same object and effect. The present invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. The present invention includes a configuration that can achieve the same operational effects or achieve the same objects as the configurations described in the embodiments. The present invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

The following can be derived from the above-described embodiment and modification examples.

One mode of the bonding material is a bonding material for forming a fiber body, which comprises a polyester comprising a structural unit derived from polyethylene terephthalate, a structural unit derived from a polycarboxylic acid, and a structural unit derived from a polyol comprising trimethylolpropane, and an aggregation inhibitor, and bonds the fiber and the fiber, and has a viscosity at 150 ℃ higher than 3500 poise in a dynamic viscoelasticity measurement.

The viscosity of the bonding material at 150 ℃ is very high. Therefore, at the time of manufacturing the fibrous body, it is possible to suppress the penetration of the bonding material in the vicinity of the surface of the fibrous body toward the inside, and in this case, the wetting diffusion is easy. This makes it easy for the polyester contained in the binder near the surface of the fibrous body to adhere to the fine powder such as short fibers, thereby suppressing the falling off of the fine powder.

In the above embodiment of the bonding material, the glass transition temperature of the bonding material may be 65 ℃ or higher.

According to this binder, when stored at a temperature higher than room temperature, the flowability of the powder of the binder is less likely to change, and agglomeration of the powder of the binder due to aggregation can be suppressed, so that the storage stability is further improved.

In the above embodiment of the bonding material, the softening temperature of the bonding material may be 150 ℃ or lower.

According to the binder, a fibrous body having a further excellent mechanical strength can be formed.

In the above aspect of the binder, the volume average particle diameter of the binder may be 12 μm or less.

According to the binder, the shedding of the fine powder can be further suppressed when the fibrous body is produced. Further, according to the binder, a fibrous body having further excellent mechanical strength can be formed.

One embodiment of the fiber forming apparatus includes the bonding material according to any one of the above embodiments.

According to the fiber forming apparatus, when the fiber is produced, the generation of particles such as fiber powder can be suppressed by the binder. This can suppress accumulation of particles in the apparatus to a small level, for example.

One embodiment of a method of forming a fiber body includes: a step of mixing fibers and a binder to obtain a mixture; and a step of heating the mixture, the bonding material including a polyester and an agglutination inhibitor, the polyester including a structural unit derived from polyethylene terephthalate, a structural unit derived from a polycarboxylic acid, and a structural unit derived from a polyol, the polyol including trimethylolpropane, the bonding material having a viscosity at 150 ℃ higher than 3500 poise in a dynamic viscoelasticity measurement.

According to this fiber forming method, a binder having a very high viscosity at 150 ℃ is used. Therefore, when the mixture is heated, the penetration of the bonding material in the vicinity of the surface of the fibrous body toward the inside can be suppressed, and the bonding material is easily wet-diffused in this case. This makes it easy for the polyester contained in the binder near the surface of the fibrous body to adhere to the fine powder such as short fibers, and thus the fibrous body in which the falling-off of the fine powder is suppressed can be produced.

Description of the symbols

1 … hopper; 2.3, 7, 8 … tubes; 9 … hopper; 10 … supply part; 12 … coarse crushing part; 14 … coarse crushing blades; 20 … defibering part; 22 … introduction port; 24 … discharge ports; 40 … screening part; 41 … a roller portion; 42 … introduction port; 43 … cover part; 44 … discharge port; 45 … a first web forming portion; 46 … mesh belt; 47. 47a … tension roller; 48 … suction mechanism; 49 … a rotating body; 49a … base; 49b … projection; a 50 … mixing section; 52 … an additive supply part; 54 … tubes; a 56 … blower; 60 … stacking part; 61 … roller part; 62 … introduction port; 63 … a cover portion; 70 … second web forming portion; 72 … mesh belt; 74 … tension roller; 76 … suction mechanism; 78 … humidity conditioning section; 80 … sheet forming part; 82 … pressure part; 84 … heating section; 85 … calender rolls; 86 … heated roller; a 90 … cut-off portion; 92 … a first cut-out; 94 … second cut-out; 96 … discharge; 100 … fiber manufacturing apparatus.