Composite body, molded body, and method for producing molded body
阅读说明：本技术 复合体、成形体及成形体的制造方法 (Composite body, molded body, and method for producing molded body ) 是由 横川忍 田中英树 中井葉子 樋口尚孝 关俊一 于 2021-03-25 设计创作，主要内容包括：本发明提供一种复合体、成形体以及成形体的制造方法,该复合体抑制源自石油的材料的使用并且即使几乎不给予水分也能够适当地使用于具有所期望的形状的成形体的制造中,该成形体抑制源自石油的材料的使用并且具有所期望的形状,该成形体的制造方法能够适当地应用于上述成形体的制造中。本发明的复合体包含纤维和淀粉,所述淀粉中的至少一部分与所述纤维融合,所述淀粉的重均分子量为4万以上且40万以下。此外,本发明的成形体的制造方法具有：成形用原料准备工序,准备包含纤维、及重均分子量为4万以上且40万以下的淀粉的成形用原料；加湿工序,对所述成形用原料进行加湿；成形工序,对所述成形用原料进行加热加压,以使之成形为预定的形状。(The present invention provides a composite body which suppresses the use of a petroleum-derived material and can be suitably used for producing a molded body having a desired shape even with little water, a molded body which suppresses the use of a petroleum-derived material and has a desired shape, and a method for producing a molded body which can be suitably applied to the production of the molded body. The composite of the present invention comprises fibers and starch, at least a part of the starch being fused to the fibers, the starch having a weight average molecular weight of 4 to 40 ten thousand. The method for producing a molded article of the present invention comprises: a molding material preparation step of preparing a molding material containing fibers and starch having a weight average molecular weight of 4 to 40 ten thousand; a humidifying step of humidifying the molding material; and a molding step of heating and pressing the molding material to mold the molding material into a predetermined shape.)
1. A composite body characterized by a composite body comprising,
comprises a fiber and a starch, wherein the fiber is a starch,
at least a portion of the starch is fused to the fibers,
the weight average molecular weight of the starch is more than 4 ten thousand and less than 40 ten thousand.
2. The composite of claim 1, wherein,
the content of the starch is 2.0 mass% or more and 15.0 mass% or less with respect to the total amount of the composite.
3. The complex of claim 1 or 2,
the composite has a water content of 20 to 55 mass% when left for two hours in an environment of 27 ℃/98% RH.
4. The composite of claim 1, wherein,
the fiber is composed of a substance having a chemical structure including at least one of a hydroxyl group, a carbonyl group, and an amino group.
5. The composite of claim 1, wherein,
the fibers are cellulosic fibers.
6. A shaped body characterized in that it comprises,
comprising the complex of any one of claims 1 to 5.
7. The shaped body as claimed in claim 6, wherein,
the shaped body is in the form of a sheet.
8. A method for manufacturing a molded body, comprising:
a molding material preparation step of preparing a molding material containing fibers and starch having a weight average molecular weight of 4 to 40 ten thousand;
a humidifying step of humidifying the molding material;
and a molding step of heating and pressing the molding material to mold the molding material into a predetermined shape.
9. The method for producing a shaped body according to claim 8, wherein,
the moisture content of the molding material at the end of the humidifying step is 15 mass% or more and 50 mass% or less.
10. The method for producing a shaped body according to claim 8 or 9, wherein,
the molding material is a material for a defibrinated product comprising a sheet-like composite, and the composite comprises the fiber and the starch.
Technical Field
The present invention relates to a composite body, a molded body, and a method for producing a molded body.
Background
A method for producing a sheet-like or film-like molded article using a fibrous substance includes a method for producing a sheet using water.
In such a sheet-making method, the fibers are entangled with each other by a bonding force such as a hydrogen bond between the fibers, and the bonding force is exerted, thereby obtaining a sufficient strength in the molded article.
However, such a papermaking method requires a large amount of water, and also requires dehydration, drying, and the like in the production process, and thus requires a very large amount of energy and time. The used water needs to be appropriately treated as drainage water. Further, the devices used for the paper making method often require large-scale utilities and infrastructures such as water, electricity, and drainage facilities, making miniaturization difficult.
Therefore, as a method of using no large amount of water as in the conventional papermaking method, there has been proposed a method of producing a sheet by stacking a mixture of dried fibers and a resin and then heating and pressurizing the stacked mixture (for example, see patent document 1).
In the method described in patent document 1, a resin such as a polyester resin is used for bonding fibers to each other, thereby securing the strength of a sheet as a molded article.
In recent years, in order to cope with environmental problems and conservation of storage resources, it has been desired to suppress the use of materials derived from petroleum.
In contrast, in the invention described in patent document 1, a synthetic resin is used for bonding fibers.
In order to meet the above-described requirements, it is preferable to use a natural material derived from plants, but in the invention described in patent document 1, if only a natural material is used instead of a synthetic resin, a sufficient adhesive force cannot be obtained, and it is difficult to sufficiently improve the strength of the sheet. Further, when a natural material is used instead of a synthetic resin, there are problems that processability is generally lowered and a heating temperature needs to be further increased, and therefore, recycling of a molded article is also difficult.
Patent document 1: international publication No. 2018/43034
Disclosure of Invention
The present invention has been made to solve the above problems, and can be realized as the following application examples.
The composite according to an application example of the present invention includes a fiber and a starch, at least a part of the starch is fused to the fiber, and the weight average molecular weight of the starch is 4 to 40 ten thousand.
The molded article according to an application example of the present invention includes the composite according to the present invention.
Further, a method for producing a molded body according to an application example of the present invention includes: a molding material preparation step of preparing a molding material containing fibers and starch having a weight average molecular weight of 4 to 40 ten thousand; a humidifying step of humidifying the molding material; and a molding step of heating and pressing the molding material to mold the molding material into a predetermined shape.
Drawings
Fig. 1 is a schematic enlarged view showing a preferred embodiment of the composite of the present invention.
Fig. 2 is a schematic side view showing a preferred embodiment of the molded body manufacturing apparatus.
Detailed Description
Hereinafter, preferred embodiments of the present invention will be described in detail.
[1] Composite body
First, the complex of the present invention will be explained.
Fig. 1 is a schematic enlarged view showing a preferred embodiment of the composite of the present invention.
The composite C100 of the present invention comprises fiber C1 and starch C2, and at least a portion of the starch C2 is fused to the fiber C1. The weight average molecular weight of starch C2 was 4 to 40 ten thousand.
By using such a composite C100, it is possible to appropriately produce a molded body having a desired shape with only a small amount of water while suppressing the use of a material derived from petroleum. That is, the present invention can be preferably applied to a dry molding method. Therefore, it is also advantageous from the viewpoints of productivity and production cost of the molded body, energy saving, downsizing of manufacturing equipment of the molded body, and the like. Further, by using starch having such a predetermined molecular weight as described above, the water absorption is improved, and even when a small amount of water is supplied, the gelatinization by heating is appropriately performed. As a result, the productivity of the molded body using the composite C100 can be improved. Further, the starch C2 having the predetermined molecular weight can be properly alphatized by heating with a small amount of water, and exhibits excellent covering properties with respect to the fiber C1 by exhibiting a bonding force with the fiber C1 by a noncovalent bond such as a hydrogen bond between the starch C2 and the fiber C1, so that the strength and the like of the molded article produced from the composite C100 can be made excellent. Further, the starch C2 having such a predetermined molecular weight is less likely to undergo unintended modification by the addition of moisture, and the molded article produced from the composite C100 is excellent in recyclability. Further, scattering of the fibers C1 and the like during production of a molded article using the composite C100 can be more effectively prevented. Further, the composite C100 and the molded article produced from the composite C100 are excellent in biodegradability. Further, since the binding power of starch can be exhibited with a small amount of moisture, the molded article obtained is excellent in recyclability when the molded article is dry-manufactured again. The recyclability as used herein means the degree of deterioration of the performance of a molded article to be produced when a dry molded article is produced again from a raw material obtained by defibering a molded article containing fibers and starch. That is, if the tensile strength and the like of the molded article to be produced again are excellent, the recyclability is excellent, and if the tensile strength and the like are inferior, the recyclability is inferior.
On the other hand, when the above condition is not satisfied, satisfactory results cannot be obtained.
For example, even if the composite is a composite including fibers and starch fused to the fibers, if the weight average molecular weight of the starch is less than the lower limit, the strength of the molded article produced from the composite cannot be sufficiently improved.
In addition, even in the case of a composite body including fibers and starch fused with the fibers, if the weight average molecular weight of the starch exceeds the upper limit, the water absorption of the starch decreases, and therefore, it is necessary to treat the starch with a large amount of water before heating, which is not preferable from the viewpoint of energy saving because the productivity and production cost of a molded body using the composite body are significantly deteriorated, and the manufacturing facility of the molded body is also increased in size. In addition, the recyclability of the molded article produced from the composite is also significantly reduced.
The weight average molecular weight of starch C2 can be determined by gel permeation chromatography. The weight average molecular weight shown in the examples described below is also a value obtained from measurement based on gel permeation chromatography. In the present invention, the dry molding method is a method in which the molding material is not immersed in the water-containing liquid during the production of the molded article, but a method in which a small amount of water is used, for example, a method in which the water-containing liquid is sprayed in the form of a mist onto the molding material or the like, is also included in the dry molding method.
[1-1] fibers
Composite C100 includes fiber C1.
The fiber C1 is generally a main component of the molded article produced from the composite C100, and is a component that contributes greatly to the retention of the shape of the molded article and greatly affects the properties such as the strength of the molded article.
Preferably, the fiber C1 is made of a material having a chemical structure including at least one of a hydroxyl group, a carbonyl group, and an amino group.
As a result, hydrogen bonds are easily formed between the fiber C1 and the starch C2 described in detail later, and the bonding strength between the fiber C1 and the starch C2, the strength of the entire molded product produced from the composite C100, for example, the tensile strength of a sheet-like molded product, and the like can be further improved.
The fiber C1 is a synthetic fiber made of a synthetic resin such as polypropylene, polyester, or polyurethane, but is preferably a natural fiber, i.e., a fiber derived from biomass, and more preferably a cellulose fiber.
This makes it possible to appropriately cope with environmental problems, saving of storage resources, and the like.
In particular, when the fiber C1 is a cellulose fiber, the following effects can be obtained.
That is, cellulose is a natural material derived from plants and is abundant, and by using cellulose as the fiber constituting the composite C100, it is possible to more appropriately cope with environmental problems, saving of storage resources, and the like, and it is preferable from the viewpoint of stable supply of the composite C100 and a molded body produced using the same, cost reduction, and the like. Among various fibers, cellulose fibers are particularly high in theoretical strength, and are advantageous from the viewpoint of further improving the strength of the molded body.
Although the cellulose fiber is usually mainly composed of cellulose, it may contain a component other than cellulose. Examples of such components include hemicellulose and lignin.
As the cellulose fiber, a cellulose fiber subjected to a treatment such as bleaching may be used.
The fiber C1 may be subjected to ultraviolet irradiation treatment, ozone treatment, plasma treatment, or the like. This can increase the hydrophilicity of the fiber C1, and can increase the affinity thereof for the starch C2. More specifically, by these treatments, functional groups such as hydroxyl groups can be introduced into the surface of the fiber C1, and hydrogen bonds can be formed with the starch C2 more efficiently.
Although composite C100 included fiber C1 and also included starch C2, and at least a portion of starch C2 was fused to fiber C1, composite C100 may also include fiber C1, to which starch C2 would not be fused, in addition to fiber C1, to which starch C2 would be fused.
The average length of the fiber C1 is not particularly limited, but is preferably 0.1mm or more and 50mm or less, more preferably 0.2mm or more and 5.0mm or less, and further preferably 0.3mm or more and 3.0mm or less.
This can further improve the stability of the shape, strength, and the like of the molded body produced from the composite C100.
The average thickness of the fiber C1 is not particularly limited, but is preferably 0.005mm or more and 0.5mm or less, and more preferably 0.010mm or more and 0.05mm or less.
This can further improve the stability of the shape, strength, and the like of the molded body produced from the composite C100. Further, it is possible to more effectively prevent the occurrence of unintended unevenness on the surface of the molded body produced from the composite body C100.
The average aspect ratio of the fiber C1, that is, the average length to the average thickness is not particularly limited, but is preferably 10 or more and 1000 or less, and more preferably 15 or more and 500 or less.
This can further improve the stability of the shape, strength, and the like of the molded body produced from the composite C100. Further, it is possible to more effectively prevent the occurrence of unintended unevenness on the surface of the molded body produced from the composite body C100.
The content of the fiber C1 in the composite C100 is not particularly limited, but is preferably 60.0 mass% or more and 99.0 mass% or less, more preferably 85.0 mass% or more and 98.0 mass% or less, and still more preferably 88.0 mass% or more and 97.0 mass% or less.
This can further improve the stability of the shape and the properties such as strength of the molded body produced from the composite C100. Further, the moldability in the production of the molded body can be further improved, and the productivity of the molded body can be improved.
[1-2] starch
Composite C100 comprises starch C2 of a predetermined weight average molecular weight as described previously.
Starch C2 is a component that functions as a binder for binding the fibers C1 to each other in the molded body produced from the composite C100. In particular, since starch C2 is a biomass-derived raw material, the use of starch C2 can appropriately cope with environmental problems, conservation of storage resources, and the like. Further, by providing starch C2 with a predetermined weight average molecular weight as described above, the water absorption is improved, and when water is supplied, the water can be absorbed quickly. In addition, the starch is properly gelatinized at a low temperature with a small amount of moisture relative to the amount of starch, thereby exhibiting excellent binding properties.
Starch C2 is a polymer material in which a plurality of α -glucose molecules are polymerized by glycosidic bonds.
The starch C2 contains at least one of amylose and amylopectin.
As described above, the weight average molecular weight of the starch C2 is 4 ten thousand or more and 40 ten thousand or less, but is preferably 6 ten thousand or more and 35 ten thousand or less, and more preferably 8 ten thousand or more and 30 ten thousand or less.
This more remarkably exerts the aforementioned effects.
The starch C2 has a smaller molecular weight than conventional starch.
The starch C2 controlled in this way to have a weight average molecular weight within a predetermined range can be suitably obtained by, for example, performing the following processes: the method comprises suspending natural starch in water, allowing sulfuric acid, hydrochloric acid or sodium hypochlorite to act under conditions where the starch is not gelatinized, or diluting the natural starch with water directly or after adding a very small amount of a volatile acid such as hydrochloric acid, drying the starch at a low temperature after mixing well, ripening, and heating to 120 to 180 ℃, or hydrolyzing a paste solution obtained by heating the natural starch together with water with an acid or an enzyme.
As the natural starch to be used as a raw material of the starch C2, for example, various plant-derived materials can be used, and more specifically, for example, cereals such as corn, wheat and rice, beans such as broad bean, mung bean and small bean, potatoes such as potato, sweet potato and cassava, weeds such as pig tooth flower, bracken and kudzu, and palms such as coconut tree can be used.
Although composite C100 includes fiber C1 along with starch C2 and at least a portion of starch C2 fused to fiber C1, as described above, composite C100 may also include starch C2 not fused to fiber C1 along with starch C2 fused to fiber C1.
The content of the starch C2 in the total amount of the composite C100 is preferably 0.5 mass% or more and 40.0 mass% or less, more preferably 2.0 mass% or more and 15.0 mass% or less, and still more preferably 3.0 mass% or more and 10.0 mass% or less.
This makes it possible to particularly improve the water absorption of the composite C100, and to further improve the shape stability, strength, and other properties of the molded article produced from the composite C100. Further, the moldability in the production of the molded body can be further improved, and the productivity of the molded body can be improved.
The content of the starch C2 in the composite C100 is preferably 0.5 parts by mass or more and 66.7 parts by mass or less with respect to 100 parts by mass of the fiber C1, more preferably 2.0 parts by mass or more and 17.7 parts by mass or less, and still more preferably 3.1 parts by mass or more and 11.1 parts by mass or less.
This can further improve the stability of the shape and the properties such as strength of the molded body produced from the composite C100. Further, the moldability in the production of the molded body can be further improved, and the productivity of the molded body can be improved.
[1-3] other Components
The composite C100 may also comprise ingredients other than the fiber C1 and starch C2 described above.
Examples of such components include natural gums such as etherified tamarind gum, etherified locust bean gum, etherified guar gum, and gum arabic; cellulose inductive paste such as etherified carboxymethyl cellulose and hydroxyethyl cellulose; polysaccharides such as glycogen, hyaluronic acid, etherified starch, esterified starch and the like; seaweed like sodium alginate and agar; animal proteins such as collagen, gelatin, and hydrolyzed collagen; an adhesive; impurities derived from fiber C1; impurities derived from starch C2, and the like.
However, the content of the components other than the fiber C1 and the starch C2 in the composite C100 is preferably 10% by mass or less, more preferably 5.0% by mass or less, and still more preferably 2.0% by mass or less.
The water content of the composite C100 when left standing for two hours in an environment of 27 ℃/98% RH is preferably 20% by mass or more and 55% by mass or less, more preferably 22% by mass or more and 50% by mass or less, and still more preferably 25% by mass or more and 40% by mass or less.
Thus, the water content is increased by mixing the fiber and the starch, so that the water absorption rate of the composite can be increased, and water can be uniformly supplied to the interior of the composite.
The water content can be measured by, for example, separating 0.7g of the composite C100, sieving the composite in a disk shape using Raffine stainless steel automatic powder sieve M manufactured by Pearl Metal Co., Ltd and laminating the composite on cooking paper, placing the cooking sheet on a stainless steel sieve basket (manufactured by shin-Etsu Co., Ltd.), in a thermostat (thermo-hygrostat platins (registered trademark) K series PL-3 KPH manufactured by Espeek Ltd., the water content was measured by using a heat drying type moisture meter (MX-50, manufactured by A & B) or the like under the condition that the sample was left for two hours with the environment set at 27 ℃/98% RH, the water content of the composite when left for two hours in an environment of 27 ℃/98% RH shown in the examples described below is also a value obtained by measurement under such conditions.
[2] Formed body
Next, the molded article of the present invention will be explained.
The molded article of the present invention is configured to include the composite C100 of the present invention described above.
This makes it possible to provide a molded body having a desired shape while suppressing the use of a material derived from petroleum. Further, such a molded body is also excellent in biodegradability. Further, such a molded article is also excellent in recyclability, strength, and the like.
The shape of the molded article of the present invention is not particularly limited, and may be any shape such as a sheet, a block, a sphere, a three-dimensional shape, etc., but the molded article of the present invention is preferably a sheet. The sheet-like form referred to herein means a form having a thickness of 30 μm or more and 30mm or less and a density of 0.05g/cm3Above and 1.5g/cm3A molded body molded in the following manner.
Thus, for example, the molded body can be suitably used as a recording medium or the like. Further, by using the manufacturing method and manufacturing apparatus described below, the manufacturing can be performed more efficiently.
When the molded article of the present invention is a sheet-like recording medium, the thickness thereof is preferably 30 μm or more and 3mm or less.
This enables the molded body to be used more appropriately as a recording medium. Further, by using the manufacturing method and manufacturing apparatus described below, the manufacturing can be performed more efficiently.
When the molded article of the present invention is a liquid absorbent, the thickness thereof is preferably 0.3mm to 30 mm.
This enables the molded body to be more suitably used as a liquid absorber. Further, by using the manufacturing method and manufacturing apparatus described below, the manufacturing can be performed more efficiently.
In the case where the molded article of the present invention is a sheet-like recording medium, the density thereof is preferably 0.6 g/mlm3Above and 0.9g/m3The following.
This enables the molded body to be used more appropriately as a recording medium.
When the molded article of the present invention is a liquid absorbent, the density is preferably 0.05g/m3Above and 0.4g/m3The following.
This enables the molded body to be more suitably used as a liquid absorber.
The molded article of the present invention may have a portion that is not constituted by the composite C100 of the present invention, as long as at least a part of the molded article is constituted by the composite C100 of the present invention described above.
The use of the molded article of the present invention is not particularly limited, and examples thereof include a recording medium, a liquid absorber, a cushion material, and a sound absorbing material.
The molded article of the present invention may be used after the molding step by subjecting it to mechanical processing such as cutting and various chemical treatments.
[3] Method for producing molded body
Next, a method for producing the molded article of the present invention will be described.
The method for producing a molded article of the present invention comprises: a molding material preparation step of preparing a molding material containing fibers and starch having a weight average molecular weight of 4 to 40 ten thousand; a humidifying step of humidifying the molding material; and a molding step of heating and pressurizing the molding material to mold the molding material into a predetermined shape.
Thus, a method for producing a molded body can be provided, in which the use of a petroleum-derived material is suppressed, and a molded body having a desired shape can be suitably produced even with little water. Therefore, it is also advantageous from the viewpoints of productivity and production cost of the molded body, energy saving, downsizing of manufacturing equipment of the molded body, and the like. In addition, the molded body produced by the production method of the present invention is also excellent in biodegradability. In addition, the molded article produced by the method of the present invention can be easily recycled. Further, the strength and the like of the molded body can be made excellent, and the scattering and the like of the fibers at the time of production of the molded body can be more effectively prevented.
[3-1] preparation of raw Material for Molding
In the molding material preparation step, a molding material containing fibers and starch having a weight average molecular weight of 4 to 40 ten thousand is prepared.
Preferably, the fibers constituting the molding material satisfy the same conditions as described in [1-1] above.
Thereby, the aforementioned effects are obtained.
The starch constituting the molding material may have a weight average molecular weight of 4 to 40 ten thousand, but preferably satisfies the same conditions as described in [1-2 ].
Thereby, the aforementioned effects are obtained.
When the molding material is a material containing granular starch, the average particle diameter of the starch is preferably 1 μm or more and 100 μm or less, more preferably 3 μm or more and 50 μm or less, and still more preferably 5 μm or more and 30 μm or less.
This makes it possible to further appropriately adjust the ease of handling and fluidity of the starch, and to further appropriately prepare the molding material. Further, the unintentional removal of starch from the molding material in a state in which the fiber and the starch are mixed can be more effectively suppressed.
In the present specification, the average particle size refers to a volume-based average particle size, and can be obtained, for example, by: the dispersion after adding a sample to a dispersion medium in which the sample does not dissolve and swell and dispersing for three minutes by an ultrasonic disperser was measured by a Coulter counter method particle size distribution analyzer (COOLTER ELECTRONICS INS TA-II type) with a pore diameter of 50 μm.
The molding material may contain other components in addition to the above-mentioned fiber and starch. Examples of such components include the components described in [1-3] above.
The molding material used in the method for producing a molded article of the present invention may be a material containing fibers and starch having a weight average molecular weight of 4 to 40 ten thousand, but is preferably the composite of the present invention described above. That is, the molding material preferably contains fibers and starch, at least a part of the starch is fused with the fibers, and the weight average molecular weight of the starch is 4 to 40 ten thousand.
This can more effectively prevent the starch from unintentionally falling off in the process of producing a molded body, for example, in the process from the formation of the fiber material M1 to the formation of the first web M5 in the method using the molded body production apparatus 100 described below, and can more reliably obtain a molded body containing starch in a preferable form and amount.
When the molding material is the composite of the present invention described above, it is preferable that the molding material satisfies the same conditions as described in [1 ].
Thereby, the aforementioned effects are obtained.
In particular, the molding material is preferably a material containing a defibrinated product of the composite in a sheet form, the composite containing fiber and starch.
Therefore, the defibrinated material is generally in the form of cotton, and can be suitably used for the production of molded articles having various shapes and thicknesses. Further, by using the sheet-like composite as a raw material of the defibrinated product, the raw material for molding can be easily prepared. Further, since the molding material can be easily prepared from the sheet-like composite only in a necessary amount as necessary, the space required for storing the material can be reduced, which contributes to the downsizing of the molded body manufacturing apparatus. In the case where the sheet-like composite is used as waste paper used as a recording medium or the like, and a sheet-like molded body is produced therefrom, it is preferable that the number of times of reuse and the number of times of recycling of the composite can be increased more appropriately.
[3-2] humidifying step
In the humidifying step, the molding material is humidified.
In this way, in the molding step described below, the bonding strength between the fibers and the starch and the bonding strength between the fibers obtained via the starch can be made excellent, and the strength of the molded article finally obtained can be made sufficiently excellent. Further, the molding in the molding step can be appropriately performed under relatively stable conditions.
The method of humidifying the molding material is not particularly limited, but is preferably performed in a non-contact manner with respect to the molding material, and examples thereof include a method of placing the molding material in a high-humidity atmosphere, a method of passing the molding material through a high-humidity space, a method of blowing a mist of a liquid containing water toward the molding material, a method of passing the molding material through a space in which the mist of the liquid containing water floats, and the like, and one or two or more methods selected from these methods can be combined. The liquid containing water may contain, for example, an antiseptic, an antifungal agent, an insecticide, and the like.
The humidification of the molding material may be performed in a plurality of stages in the process of producing the molded product, for example.
More specifically, for example, two or more of the following modes may be combined: the humidifying step includes humidifying a sheet-like composite including fibers and starch, humidifying coarse pieces of the sheet-like composite, humidifying a web obtained by stacking the defibrinated matter, and humidifying a composition including the defibrinated matter of the sheet-like composite, for example, a defibrinated matter obtained by defibrinating coarse pieces.
As described above, the raw material for forming is humidified in a plurality of stages in the process of producing the formed body, so that, for example, it is not necessary to increase the amount of humidification in each stage to a necessary level or more. As a result, for example, the conveying speed of the molding material or the like in the molded body manufacturing apparatus can be increased, and the productivity of the molded body can be further improved.
The amount of water to be supplied to the molding material in the humidifying step is not particularly limited, but the water content of the molding material at the end of the humidifying step, that is, the ratio of the mass of water contained in the molding material at the end of the humidifying step to the mass of the molding material is preferably 15 mass% or more and 50 mass% or less, more preferably 18 mass% or more and 45 mass% or less, and still more preferably 20 mass% or more and 40 mass% or less.
This makes it possible to more appropriately absorb water in the starch, and to more appropriately perform the subsequent molding step. As a result, the strength, reliability, and the like of the molded article finally obtained can be further improved. In addition, since the time required for the absorption of water by starch can be made short, the productivity of the molded body can be further improved. Further, compared to the paper-making method, the energy consumption required for heating in the subsequent forming step can be significantly reduced.
The moisture content can be determined by measurement using a heat drying moisture meter manufactured by a & D company or the like.
[3-3] Molding Process
In the molding step, the humidified molding material is heated and pressurized to be molded into a predetermined shape. Thus, the molded article of the present invention in which fibers are bonded to each other by the fused starch is obtained. The humidifying step and the shaping step may be performed simultaneously.
The heating temperature in the molding step is not particularly limited, but is preferably 60 ℃ to 180 ℃, more preferably 70 ℃ to 170 ℃, and still more preferably 80 ℃ to 160 ℃.
This makes it possible to appropriately convert the water-absorbing starch into α -form, and also effectively prevent the material constituting the molded body from being unintentionally deteriorated, and is preferable from the viewpoint of energy saving. Further, the molded article obtained can be further improved in heat resistance, mechanical strength at a relatively low temperature such as room temperature, and the like. The temperature is sufficiently lower than that in the case where polyester, which is a synthetic resin, is used as the binder.
The pressurization in the molding step is preferably performed at 0.1MPa to 100MPa, and more preferably at 0.3MPa to 20 MPa.
This step can be performed by, for example, a hot press, a hot roll, or the like.
[3-4] apparatus for producing molded article
Next, a molded body manufacturing apparatus that can be preferably applied to the method for manufacturing a molded body of the present invention will be described.
Fig. 2 is a schematic side view showing a preferred embodiment of the molded body manufacturing apparatus.
Hereinafter, the upper side of fig. 2 is sometimes referred to as "upper" or "upper", and the lower side is sometimes referred to as "lower" or "lower".
Fig. 2 is a schematic configuration diagram, and the positional relationship of each part of the molded body manufacturing apparatus 100 is different from the illustrated positional relationship. In the drawings, the direction in which the fiber material M1, the coarse chips M2, the defibrinated material M3, the first screen M4-1, the second screen M4-2, the first web M5, the finely divided body M6, the mixture M7, the second web M8, and the sheet S are conveyed, that is, the direction indicated by an arrow mark is also referred to as the conveyance direction. The tip side of the arrow mark is also referred to as the downstream side in the conveying direction, and the base end side of the arrow mark is also referred to as the upstream side in the conveying direction.
The molded body manufacturing apparatus 100 shown in fig. 2 is an apparatus for obtaining a molded body by roughly crushing, defibrating, and stacking a fiber material M1, and molding the stack by the molding section 20.
The molded body manufactured by the molded body manufacturing apparatus 100 may be in a sheet shape such as recycled paper, or may be in a block shape. The density of the molded body is not particularly limited, and may be a molded body having a high density of fibers such as a sheet, a molded body having a low density of fibers such as a sponge, or a molded body obtained by mixing the characteristics thereof.
As the fiber material M1, used or unnecessary waste paper can be used, for example. As the fiber material M1, for example, a sheet material containing fibers and starch fused with the fibers and having a weight average molecular weight of 4 to 40 ten thousand can be used. The sheet material may be, for example, recycled paper or non-recycled paper.
In the following description, the following description will be mainly focused on a case where waste paper as a fiber raw material M1 is used as a sheet material, which is a composite material including fibers and starch fused with the fibers and having a weight average molecular weight of 4 to 40 ten thousand, and a molded product produced is a recycled paper sheet S.
The molded body manufacturing apparatus 100 shown in fig. 2 includes a sheet feeding device 11, a coarse crushing section 12, a defibering section 13, a screening section 14, a first web forming section 15, a refining section 16, a mixing section 17, a dispersing section 18, a second web forming section 19, a molding section 20, a cutting section 21, a stacking section 22, a collecting section 27, and a control section 28 that controls operations thereof. The rough crushing section 12, the defibering section 13, the screening section 14, the first web forming section 15, the refining section 16, the mixing section 17, the dispersing section 18, the second web forming section 19, the forming section 20, the cutting section 21, and the stock section 22 are processing sections for processing sheets, respectively.
Further, the sheet processing apparatus 10A is configured by the sheet supply device 11 and the coarse crushing section 12 or the defibering section 13. Further, the sheet processing apparatus 10A and the second web forming section 19 constitute a fiber stacking apparatus 10B.
The molded body manufacturing apparatus 100 further includes a humidifying unit 231, a humidifying unit 232, a humidifying unit 233, a humidifying unit 234, a humidifying unit 235, and a humidifying unit 236. Further, the molded body manufacturing apparatus 100 includes a blower 261, a blower 262, and a blower 263.
The humidification units 231 to 236 and the blowers 261 to 263 are electrically connected to the controller 28, and their operations are controlled by the controller 28. That is, in the present embodiment, the operation of each part of the molded body manufacturing apparatus 100 is controlled by one control unit 28. However, the present invention is not limited to this, and may be configured to include a control unit that controls operations of each part of the sheet feeding device 11 and a control unit that controls operations of a part other than the sheet feeding device 11.
In the molded body manufacturing apparatus 100, the raw material supply step, the coarse crushing step, the defibering step, the screening step, the first web forming step, the cutting step, the mixing step, the discharging step, the stacking step, the sheet forming step, and the cutting step are performed in this order. The raw material supply step to the mixing step correspond to the raw material preparation step for molding in the method for producing a molded body of the present invention, and the sheet forming step corresponds to the molding step in the method for producing a molded body of the present invention. The step of humidifying by each humidifying unit, which will be described in detail later, corresponds to the humidifying step.
The structure of each part will be explained below.
The sheet supply device 11 is a part that performs a raw material supply step of supplying the fiber raw material M1 to the coarse crushing section 12. As described above, as the fiber material M1, a composite including a fiber and a starch fused to the fiber and having a weight average molecular weight of 4 to 40 ten thousand can be suitably used. In particular, as the fiber material M1, a material containing cellulose fibers as fibers can be suitably used.
The rough grinding section 12 is a section for performing a rough grinding step of roughly grinding the fiber material M1 supplied from the sheet supply device 11 in a gas such as air. The rough crush portion 12 has a pair of rough crush blades 121 and a chute 122.
The pair of rough crush blades 121 are rotated in opposite directions to each other, so that the fiber material M1 can be roughly crushed, i.e., divided, into rough crush pieces M2 therebetween. The shape and size of the coarse pieces M2 are preferably suitable for the defibration process in the defibration section 13, and for example, pieces with a side length of 100mm or less are preferable, and pieces with a side length of 10mm to 70mm are more preferable.
The chute 122 is a member, for example, a funnel-shaped member, which is disposed below the pair of rough crush blades 121. Accordingly, the chute 122 can receive the coarse chips M2 that have been coarsely crushed by the coarse crushing blade 121 and have fallen down.
Further, the humidifying portion 231 is disposed above the chute 122 so as to be adjacent to the pair of rough crush blades 121. The humidifying unit 231 humidifies the coarse chips M2 in the chute 122. The humidifying unit 231 is configured by a vaporizing humidifier having a filter containing moisture, and supplying humidified air with increased humidity to the coarse chips M2 by passing air through the filter. By supplying the humidified air to the coarse chips M2, the humidification step described in [3-2] above can be performed, and the above-described effect can be obtained. Further, it is possible to suppress the adhesion of the coarse chips M2 to the chute 122 and the like due to static electricity.
The chute 122 is connected to the fiber splitting unit 13 via a pipe 241. The coarse chips M2 collected in the chute 122 are conveyed into the defibration section 13 through the pipe 241.
The defibering unit 13 is a part for performing a defibering process for defibering the coarse pieces M2 in a gas, that is, in a dry manner. By the defibering process in the defibering unit 13, a defibered product M3 can be generated from the coarse pieces M2. Here, "performing defibration" means a case where coarse pieces M2, which are formed by bonding a plurality of fibers, are separated into single fibers. Then, the defibered fiber becomes a defibered product M3. The shape of the defibrinated material M3 is a linear or ribbon shape. The defibrinates M3 may be entangled with each other to form a block, that is, a so-called "lump".
For example, in the present embodiment, the defibrating part 13 is configured by an impeller mixer having a rotating blade that rotates at a high speed and a bush located on the outer periphery of the rotating blade. The coarse pieces M2 flowing into the defibering portion 13 are sandwiched between the rotary blade and the bush to be defibered.
The defibering unit 13 can generate a flow of air, i.e., an air flow, from the coarse crushing unit 12 to the screening unit 14 by the rotation of the rotary blade. Thereby, the coarse chips M2 can be sucked from the tube 241 into the defibration section 13. After the defibering process, the defibered product M3 can be fed to the screening unit 14 through the pipe 242.
A blower 261 is provided midway in the pipe 242. The blower 261 is an airflow generating device that generates an airflow toward the sieving section 14. This facilitates the feeding of the defibrination M3 to the screening section 14.
The screening section 14 is a section for performing a screening step of screening the defibrated product M3 according to the length of the fiber. In the screening section 14, the defibrinated product M3 was screened into a first screening product M4-1 and a second screening product M4-2 that was larger than the first screening product M4-1. The first screen M4-1 was of a size suitable for subsequent production of the sheet S. The average length is preferably 1 μm or more and 30 μm or less. On the other hand, the second screen M4-2 contained, for example, a substance that was not sufficiently defibered or a substance that was formed by excessively aggregating defibered fibers.
The screening section 14 includes a roller section 141 and a housing section 142 that houses the roller section 141.
The drum portion 141 is a screen formed of a cylindrical mesh body and rotating around its central axis. In the drum portion 141, the defibrinated material M3 flows. Then, by the rotation of the drum portion 141, the defibrinated material M3 smaller than the mesh size of the net is screened as the first screened material M4-1, and the defibrinated material M3 having a size larger than the mesh size of the net is screened as the second screened material M4-2. The first screen M4-1 falls from the drum 141.
On the other hand, the second sorted material M4-2 is sent out to the pipe 243 connected to the drum 141. The pipe 243 is connected to the pipe 241 on the side opposite to the drum portion 141, i.e., on the upstream side. The second screen M4-2 having passed through the pipe 243 is merged with the coarse chips M2 in the pipe 241, and flows into the defibration section 13 together with the coarse chips M2. Thereby, the second screen material M4-2 is returned to the defibering unit 13 and is defibered together with the coarse chips M2.
Further, the first screen M4-1 falling from the drum part 141 is dispersed in the gas and falls, and falls toward the first web forming part 15 located below the drum part 141. The first web forming portion 15 is a portion where the first web forming process of forming the first web M5 from the first screen M4-1 is performed. The first web forming portion 15 has a mesh belt 151, three tension rollers 152, and a suction portion 153.
The mesh belt 151 is an endless belt, and is used for stacking the first screen M4-1. The mesh belt 151 is wound around three tension rollers 152. Then, the first screen M4-1 on the mesh belt 151 is conveyed downstream by the rotational drive of the tension roller 152.
The first screen M4-1 was larger than the mesh size of the mesh belt 151. Thereby, the passage of the first screen M4-1 through the mesh belt 151 is restricted, and therefore, the first screen M4-1 can be accumulated on the mesh belt 151. Further, since the first screen M4-1 is conveyed toward the downstream side along with the mesh belt 151 while being stacked on the mesh belt 151, the first web M5 is formed as a layer.
Further, the first screen material M4-1 may contain, for example, fly ash, dust, or the like. Fly ash and dust are sometimes generated by, for example, coarse crushing or defibration. Then, the fly ash and dust are collected in a collecting section 27 described below.
The suction unit 153 is a suction mechanism for sucking air from below the mesh belt 151. This allows the fly ash and dust passing through the mesh belt 151 to be sucked together with the air.
The suction unit 153 is connected to the recovery unit 27 via a pipe 244. The fly ash and dust sucked by the suction unit 153 are collected in the collection unit 27.
A pipe 245 is also connected to the recovery unit 27. Further, a blower 262 is provided midway in the pipe 245. By the operation of the blower 262, a suction force can be generated by the suction unit 153. Thereby, the formation of the first web M5 on the mesh belt 151 is promoted. The first web M5 is a material from which fly ash, dust, and the like are removed. Further, the fly ash and dust pass through the pipe 244 by the operation of the blower 262 and reach the recovery unit 27.
The housing 142 is connected to the humidifying unit 232. The humidifier 232 is constituted by a vaporizing humidifier. This causes humidified air to be supplied into the case 142. The humidification step described in [3-2] above can be performed by humidifying the air, and the above-described effects can be obtained. Further, since the first screen M4-1 can be humidified, it is possible to suppress the first screen M4-1 from being attached to the inner wall of the housing 142 due to static electricity.
A humidifying unit 235 is disposed downstream of the screening unit 14. The humidifying unit 235 is formed of an ultrasonic humidifier that sprays water in a mist form. Thus, moisture can be supplied to the first web M5, and therefore the moisture amount of the first web M5 is adjusted. By this adjustment, the humidification step described in [3-2] above can be performed, and the above-described effects can be obtained. Further, the adsorption of the first web M5 to the mesh belt 151 due to static electricity can be suppressed. Thus, the first web M5 is easily peeled off from the mesh belt 151 at the position where the mesh belt 151 is folded back by the bridge roller 152.
The subdividing unit 16 is disposed downstream of the humidifying unit 235. The subdividing unit 16 is a portion for performing a dividing step of dividing the first web M5 peeled off from the mesh belt 151. The subdividing unit 16 includes a rotary blade 161 rotatably supported, and a housing portion 162 that houses the rotary blade 161. The first web M5 can be divided by the rotating blade 161. The divided first web M5 becomes the narrow body M6. Further, the sub-segment M6 drops within the housing portion 162.
The case portion 162 is connected to the humidifying portion 233. The humidifier 233 is formed of a vaporizing humidifier. This causes humidified air to be supplied into the case portion 162. The humidification step described in [3-2] above can be performed by humidifying the air, and the above-described effects can be obtained. Further, the sub-segment M6 can be prevented from being attached to the inner wall of the rotary blade 161 or the housing 162 by static electricity.
A mixing section 17 is disposed downstream of the subdividing section 16. The mixing section 17 is a section for performing a mixing step of mixing the finely divided body M6 and the additive. The mixing section 17 includes an additive supply section 171, a pipe 172, and a blower 173.
The pipe 172 is a flow passage for connecting the casing 162 of the subdividing section 16 and the casing 182 of the dispersing section 18 and for passing the mixture M7 of the subdividing body M6 and the additive.
An additive supply unit 171 is connected to an intermediate portion of the pipe 172. The additive supply unit 171 includes a housing 170 for containing an additive, and a screw feeder 174 provided in the housing 170. By the rotation of the screw feeder 174, the additive in the housing part 170 is pushed out from the housing part 170 and supplied into the tube 172. The additive supplied into the pipe 172 is mixed with the finely divided body M6 to become a mixture M7.
Examples of the additive supplied from the additive supply unit 171 include a binder for binding fibers to each other, a coloring agent for coloring fibers, an aggregation inhibitor for inhibiting aggregation of fibers, a flame retardant for making fibers or the like nonflammable, a paper strength enhancer for enhancing the paper strength of the sheet S, and a defibrinated product, and one or more of these may be used in combination. Hereinafter, the description will be made mainly on the case where the additive is starch P1 as a binder, particularly starch P1 having a weight average molecular weight of 4 ten thousand or more and 40 ten thousand or less.
By supplying the starch P1 from the additive supply unit 171, a sheet S, which is a preferable molded body, can be obtained even when the content of starch in the fiber material M1 is low and when a large proportion of starch contained in the fiber material M1 is removed by the treatment using the molded body manufacturing apparatus 100. That is, the content of starch in the sheet S, which is a molded body to be finally obtained, can be sufficiently high, and the starch can be fused with the fibers constituting the sheet S with high adhesiveness, and as a result, the above-described effects can be more remarkably exhibited.
Preferably, the starch P1 satisfies the same conditions as the starch C2 described in [1-2] above as a constituent of the complex C100.
Thereby, the same effects as described above are obtained.
As the additive supplied from the additive supply unit 171, a composite of the present invention, that is, a composite including fibers and starch fused to the fibers and having a weight average molecular weight of 4 to 40 ten thousand may be used instead of the starch P1.
Thus, for example, when a sheet material including fibers and starch having a weight average molecular weight of 4 to 40 ten thousand fused to the fibers is used as the fiber material M1, even when the mixing step in the mixing section 17 is simplified, it is possible to suppress the variation in the unintended composition in the second web M8, particularly the variation in the presence of starch having a weight average molecular weight of 4 to 40 ten thousand at each site. As a result, it is possible to suppress unintended composition variations and the like in the sheet S as a molded body finally obtained, and to further improve the reliability of the sheet S.
Further, a blower 173 is provided midway in the pipe 172 on the downstream side of the additive supply unit 171. The mixing of the finely divided body M6 and the starch P1 is promoted by the action of a rotating part such as a blade provided in the blower 173. Further, the blower 173 can generate an air flow toward the dispersing section 18. By this air flow, the finely divided body M6 and the starch P1 can be stirred in the pipe 172. Thereby, the mixture M7 is conveyed to the dispersing unit 18 in a state where the finely divided body M6 and the starch P1 are uniformly dispersed. Further, the finely divided bodies M6 in the mixture M7 are disintegrated into finer fibrous shapes while passing through the tube 172.
As shown in fig. 2, the blower 173 is electrically connected to the controller 28 to control the operation thereof. Further, by adjusting the amount of air blown by blower 173, the amount of air fed into drum 181 can be adjusted.
Although not shown, the end of the pipe 172 on the drum 181 side is bifurcated, and the bifurcated end is connected to an inlet port, not shown, formed in an end surface of the drum 181.
The dispersing section 18 shown in fig. 2 is a section for performing a discharging step of detaching and discharging intertwined fibers in the mixture M7. The dispersing unit 18 includes a drum 181 for introducing and discharging the mixture M7 as a defibrinated product, a casing 182 for housing the drum 181, and a drive source 183 for rotationally driving the drum 181.
The drum 181 is a screen formed of a cylindrical mesh body and rotating around its central axis. The drum 181 rotates, whereby fibers and the like in the mixture M7 smaller than the mesh of the net can pass through the drum 181. At this point, the mixture M7 is disassembled and discharged with the air. That is, the drum 181 functions as a discharging unit that discharges a material including fibers.
Although not shown, the driving source 183 has a motor, a reduction gear, and a belt. The motor is electrically connected to the control unit 28 via a motor driver. Further, the rotational force output from the motor is decelerated by the decelerator. The belt is constituted by, for example, an endless belt, and is wound around the output shaft of the speed reducer and the outer periphery of the drum. Thereby, the rotational force of the output shaft of the speed reducer is transmitted to drum 181 via the belt.
Further, the housing 182 is connected to the humidifying portion 234. The humidifier 234 is a gasification type humidifier. Thereby, the humidified air is supplied into the housing 182. The humidifying air can humidify the inside of the case 182, and the humidifying step described in [3-2] above can be performed, whereby the above-described effects can be obtained. Further, the mixture M7 can be prevented from adhering to the inner wall of the housing 182 due to static electricity.
The mixture M7 discharged by the drum 181 falls while being dispersed in the gas, and falls toward the second web forming section 19 located below the drum 181. The second web forming section 19 is a part where a deposition step of depositing the mixture M7 to form the second web M8 as a deposit is performed. The second web forming section 19 has a mesh belt 191, an erection roller 192, and a suction portion 193.
The mesh belt 191 is a mesh member, and in the illustrated structure, is constituted by an endless belt. Further, the mixture M7 dispersed and discharged by the dispersing section 18 is deposited on the mesh belt 191. The web 191 is wound around four tension rollers 192. The mixture M7 on the mesh belt 191 is conveyed downstream by the rotational drive of the bridge roller 192.
In the illustrated configuration, the mesh belt 191 is used as an example of the mesh member, but the present invention is not limited thereto, and may be a flat plate, for example.
Further, most of the mixture M7 on the mesh belt 191 is larger than the mesh of the mesh belt 191. This restricts the passage of the mixture M7 through the mesh belt 191, and the mixture M7 can be accumulated on the mesh belt 191. Further, since the mixture M7 is conveyed to the downstream side along with the mesh belt 191 while being accumulated on the mesh belt 191, the second web M8 is formed as a layer.
The suction unit 193 is a suction mechanism that sucks air from below the mesh belt 191. This allows the mixture M7 to be sucked onto the mesh belt 191, thereby promoting the accumulation of the mixture M7 on the mesh belt 191.
A tube 246 is connected to the suction portion 193. A blower 263 is provided in the middle of the pipe 246. By the operation of the blower 263, a suction force can be generated by the suction portion 193.
A humidifying unit 236 is disposed downstream of the dispersing unit 18. The humidifying unit 236 is constituted by an ultrasonic humidifier similar to the humidifying unit 235. This allows moisture to be supplied to the second web M8, and thus the moisture content of the second web M8 is adjusted. By this adjustment, the humidification step described in [3-2] above can be performed, and the above-described effects can be obtained. Further, the adsorption of the second web M8 to the mesh belt 191 due to static electricity can be suppressed. Thereby, the second web M8 is easily peeled off from the web 191 at the position where the web 191 is folded back by the bridge roller 192.
The total moisture amount added to the humidifying sections 231 to 236 is not particularly limited, but the moisture content of the molding material at the end of the humidifying step, that is, the ratio of the mass of the moisture contained in the second web M8 to the mass of the second web M8 in a state of being humidified in the humidifying section 236 is preferably 15 mass% or more and 50 mass% or less, more preferably 18 mass% or more and 45 mass% or less, and still more preferably 20 mass% or more and 40 mass% or less.
A forming section 20 is disposed downstream of the second web forming section 19. The forming section 20 is a portion for performing a sheet forming step of forming a sheet S from the second web M8 as a forming material. The molding section 20 includes a pressing section 201 and a heating section 202.
The pressing section 201 has a pair of reduction rollers 203, and can press the second web M8 between the reduction rollers 203 without heating. Thereby, the density of the second web M8 was increased. The second web M8 is conveyed toward the heating section 202. One of the pair of reduction rolls 203 is a drive roll driven by an operation of a motor not shown, and the other is a driven roll.
The heating section 202 has a pair of heating rollers 204, and is capable of pressurizing the second web M8 while heating it between the heating rollers 204. By the heating and the pressing, the starch that has absorbed water by humidification is converted into alphabets in the second web M8 to develop adhesiveness, and the fibers are bonded to each other via the starch that develops adhesiveness. Thereby, the sheet S is formed. Then, the sheet S is conveyed toward the cutting section 21. One of the pair of heating rollers 204 is a driving roller driven by an operation of a motor not shown, and the other is a driven roller.
A cutting section 21 is disposed downstream of the forming section 20. The cutting unit 21 is a part that performs a cutting process of cutting the sheet S. The cut-off portion 21 has a first cutter 211 and a second cutter 212.
The first cutter 211 cuts the sheet S in a direction intersecting the conveying direction of the sheet S, particularly in a direction orthogonal thereto.
The second cutter 212 is a member that cuts the sheet S in a direction parallel to the conveying direction of the sheet S on the downstream side of the first cutter 211. This cutting removes unnecessary portions at both widthwise end portions of the sheet S to thereby make the width of the sheet S uniform, and the cut and removed portions are called "trimmings".
By cutting the first cutter 211 and the second cutter 212, a sheet S having a desired shape and size is obtained. Then, the sheet S is further conveyed to the downstream side, and is stored in the stock preparation section 22.
The forming section 20 is not limited to the configuration of forming the sheet S as described above, and may be formed into a block-shaped, spherical, or other shaped body, for example.
Each part of the molded body manufacturing apparatus 100 is electrically connected to a control unit 28 described below. The operations of these respective units are controlled by the control unit 28.
Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments.
For example, each part constituting the molded body manufacturing apparatus used for manufacturing the molded body can be replaced with any structure that can exhibit the same function. In addition, any structure may be added.
In the above-described embodiment, the description has been given of the case where the fiber material including the fiber and the starch having the predetermined molecular weight is used in the method for producing the molded body using the molded body production apparatus, and the components obtained by defibrating the fiber material and the starch having the predetermined molecular weight supplied from the additive supply portion are mixed in the mixing portion, but when the fiber material including the fiber and the starch having the predetermined molecular weight is used, it is not necessary to add the starch having the predetermined molecular weight to the production of the molded body. In this case, the additive supply portion can be omitted. In addition, along with this, the subdividing section, the mixing section, the dispersing section, the second web forming section, and the like may be omitted, and the first web may be directly fed to the forming section.
The method of producing a molded body of the present invention is not limited to the case of using the apparatus for producing a molded body described above, and any apparatus may be used as long as it has the above-described raw material preparation step, humidifying step, and molding step.
Examples
Next, specific examples of the present invention will be explained.
[4] Preparation of starch
Preparation example 1
Starch (G-800, manufactured by japan starch chemical limited) having a weight average molecular weight of 130 ten thousand is prepared, and after the starch is suspended in water, sulfuric acid is allowed to act under conditions that the starch does not gelatinize, and the starch is mixed well, and after stirring for 12 hours, the mixture is dried at 50 ℃ for 24 hours, and after drying until the water content becomes 10 mass% or less, the mixture is heated to 120 to 180 ℃, whereby starch having a weight average molecular weight of 40 ten thousand is obtained.
(preparation examples 2 to 6)
Starch with an adjusted weight average molecular weight was obtained in the same manner as in preparation example 1, except that the treatment conditions (concentration of sulfuric acid, stirring time) were changed and adjusted for starch with a weight average molecular weight of 130 ten thousand (G-800, manufactured by japan starch chemical limited) so that the weight average molecular weight of the finally obtained starch became the values shown in table 1.
The conditions of the starches obtained in the respective production examples after the adjustment of the weight average molecular weight are collectively shown in table 1.
Table 1
[5] Production of composite and molded article
(example A1)
Using the molded body manufacturing apparatus 100 shown in fig. 2, a sheet S as a molded body was manufactured in the following manner.
First, a plurality of sheets of G80 (manufactured by mitsubishi paper corporation) made of cellulose fibers were prepared as the fiber material M1, and these were stored in the storage unit of the sheet supply device 11, and the starch prepared in the preparation example 1 was stored in the case 170 of the additive supply unit 171.
Thereafter, as described above, the molded body manufacturing apparatus 100 is operated.
As a result, the cellulose fibers and the starch were mixed at a predetermined ratio in the mixing section 17, and a mixture M7, which is a composite containing these components, was obtained.
The mixture M7 obtained in the mixing section 17 passes through the dispersing section 18 and becomes a second web M8 as a composite containing cellulose fibers and starch in the second web forming section 19.
The humidification is performed by the humidifying unit 231, the humidifying unit 232, the humidifying unit 233, the humidifying unit 234, the humidifying unit 235, and the humidifying unit 236 so that the ratio of the mass of the moisture contained in the second web M8 to the mass of the second web M8 in a state humidified by the humidifying unit 236 is 30 mass%, respectively.
The second web M8 is heated and pressed in the forming section 20 to form a sheet S, which is an elongated formed body. The heating temperature in the forming section 20 was 80 ℃ and the heating time was 15 seconds, and the pressing in the forming section 20 was performed at 70 MPa.
The long molded sheet S obtained in this manner is cut by the cutting section 21 to be an a4 size sheet S.
Examples A2 to A9
The production of the composite and the molded article were carried out in the same manner as in example a1, except that the type of starch supplied from the additive supplying section 171, the mixing ratio of starch and cellulose fiber in the mixing section, the heating and pressurizing conditions, and the water content of the second web as the molding material at the end of the humidifying step were set to values shown in table 2.
Comparative example A1
A molded body was produced in the same manner as in example a1, except that no starch was supplied from the additive supply unit 171. The formed body of the present comparative example obtained in this way was a formed body composed only of cellulose fibers, and did not contain starch.
Comparative examples A2 and A3
The composite and the molded article were produced in the same manner as in example a1, except that the type of the starch supplied from the additive supply unit 171 was changed from the starch prepared in production example 1 to the starch prepared in production example 5 and the starch prepared in production example 6, respectively.
Table 2 shows the composition of the molded bodies and the production conditions of the molded bodies in each of the examples and comparative examples. The fibers contained in the molded bodies obtained in the examples and comparative examples each had an average length of 0.1mm or more and 10mm or less, an average thickness of 0.05mm or more and 2.0mm or less, and an average aspect ratio of 10 or more and 1000 or less. Table 2 also shows the water content of the second web, which is the composite according to each of the examples and comparative examples, when left standing for two hours in an environment of 27 ℃/98% RH. This value was obtained by taking out a part of the second web M8 before heating and pressing in the forming section 20, drying it for 1 day in a constant temperature and humidity bath adjusted to 27 ℃/10% RH, and then leaving it in an atmosphere of 27 ℃/98% RH for two hours, and then measuring it.
TABLE 2
[6] Evaluation of
The molded bodies of the above examples and comparative examples were evaluated as follows.
[6-1] Water absorption Properties
The molded bodies of the examples and comparative examples were placed in a thermostatic bath at 27 ℃/98% RH for two hours without being overlapped with each other, and the water content in the molded bodies at that time point was determined and evaluated based on the following criteria. The higher the water content, the more excellent the water absorption property.
A: the water content is 25 mass% or more.
B: the water content is 20 to less than 25 mass%.
C: the water content is 15 mass% or more and less than 20 mass%.
D: the water content is less than 15 mass%.
[6-2] specific tensile Strength
The molded bodies of the examples and comparative examples were measured according to JISP8113 using AUTOGRAP AGC-X500N (manufactured by shimadzu corporation) to obtain specific tensile strength, and evaluated according to the following criteria.
A: the specific tensile strength is 25N m/g or more.
B: the specific tensile strength is 20 N.m/g or more and less than 25 N.m/g.
C: the specific tensile strength is 15 N.m/g or more and less than 20 N.m/g.
D: the specific tensile strength is less than 15 N.m/g.
Their results are shown collectively in table 3.
TABLE 3
TABLE 3
Water absorption characteristics
Specific tensile strength
Example A1
B
A
Example A2
A
A
Example A3
A
A
Example A4
A
A
Example A5
B
B
Example A6
A
B
Example A7
A
A
Example A8
A
B
Example A9
A
B
Comparative example A1
D
D
Comparative example A2
D
D
Comparative example A3
A
C
As can be seen from table 3, excellent results were obtained in each of the examples. In contrast, in the comparative examples, satisfactory results were not obtained.
[7] Production of molded body using the sheet S as raw material
(example B1)
The production of the sheet S as a molded body was carried out in the same manner as in example a1, except that the sheet S produced in example a1 was used as the fiber material M1 and no starch was supplied from the additive supplying portion 171.
(examples B2 to B9)
Production of the sheet S as a molded body was carried out in the same manner as in example B1, except that the sheets S produced in examples a2 to a9 were used as the fiber material M1, respectively, instead of the sheet S produced in example a 1.
Comparative examples B1 to B3
Production of the sheet S as a molded body was carried out in the same manner as in example B1, except that the sheets S produced in comparative examples a1 and A3 were used as the fiber material M1, respectively, instead of the sheet S produced in example a 1.
The molded bodies obtained in examples B1 to B9 and comparative examples B1 to B3 each contained no component other than the constituent material of the fiber raw material M1. Further, the fibers contained in the molded bodies obtained in examples B1 to B9 and comparative examples B1 to B3 all had an average length of 0.1mm or more and 10mm or less, an average thickness of 0.05mm or more and 2.0mm or less, and an average aspect ratio of 10 or more and 1000 or less, and the average length, average thickness, and average aspect ratio of these fibers and the average length, average thickness, and change rate of the average aspect ratio of the fibers contained in the corresponding fiber raw material M1 were all 30% or less.
[8] Evaluation of
The following evaluations were carried out for examples B1 to B9 and comparative examples B1 to B3.
[8-1] specific tensile Strength
The molded articles of examples B1 to B9 and comparative examples B1 to B3 were measured in accordance with JISP8113 standard using AUTOGRAP AGC-X500N (manufactured by shimadzu corporation) to determine specific tensile strength, and evaluated based on the following criteria.
A: the specific tensile strength is 20N m/g or more.
B: the specific tensile strength is 15 N.m/g or more and less than 20 N.m/g.
C: the specific tensile strength is 10 N.m/g or more and less than 15 N.m/g.
D: the specific tensile strength is less than 10 N.m/g.
Their results are shown in table 4 collectively.
Table 4
Specific tensile strength
Example B1
A
Example B2
B
Example B3
A
Example B4
B
Example B5
C
Example B6
B
Example B7
B
Example B8
A
Example B9
A
Comparative example B1
D
Comparative example B2
D
Comparative example B3
D
As is clear from Table 4, excellent results were obtained in the above examples B1 to B9. On the other hand, satisfactory results were not obtained in comparative examples B1 to B3.
Further, the same results as those described above can be obtained if the molded body is produced in the same manner as described above and the same evaluation as that described above is performed, except that the heating temperature in the molding step is changed variously within the range of 60 ℃ to 180 ℃. Further, the same results as those described above can be obtained if the molded body is produced in the same manner as described above except that the pressurization in the molding step is variously changed within the range of 0.1MPa to 100MPa, and the same evaluation as described above is performed. Note that, if the production of the formed body is carried out in the same manner as described above except that the amount of humidification in each humidification portion is adjusted and the ratio of the mass of moisture contained in the second web M8 to the mass of the second web M8 in a state of being humidified in the humidification portion 236 is variously changed within the range of 15 mass% or more and 50 mass% or less, and the same evaluation as described above is carried out, the same result as described above can be obtained.
Description of the symbols
The C100 … complex; c1 … fiber; c2 … starch; 100 … molding manufacturing device; 10a … sheet processing apparatus; 10B … fiber body stacking device; 11 … sheet feeding means; 12 … coarse crushing part; 13 … defibering part; 14 … screening part; 15 … a first web forming portion; 16 … subdivision; 17 … mixing section; 18 … dispersing part; 19 … a second web forming portion; 20 … forming section; 21 … cutting part; 22 … stock preparation; 27 … recovery part; 28 … control section; 121 … coarse crushing blade; 122 … chutes; 141 … roller part; 142 … housing portion; 151 … mesh belt; 152 … mounting rollers; 153 … suction part; 161 … rotating blades; 162 … housing portion; 170 … housing portion; 171 … additive supply; 172 … tubes; 173 a blower 173 …; 174 … screw feeder; 181 … a roller; 182 … a housing; 183 … drive source; 191 … mesh belt; 192 … mounting rollers; 193 … suction part; 201 … pressurizing part; 202 … heating section; 203 … calender rolls; 204 … heated roller; 211 … first cutter; 212 … second cutter; 231 … humidifying part; 232 … humidifying part; 233 … humidifying section; 234 … a humidifying part; 235 … a humidifying part; 236 … humidifying part; 241 … pipes; 242 … tubes; 243 … tube; 244 … tubes; 245 … tubes; 246 … tube; 261 … blower; a 262 … blower; 263 … blower; 281 … CPU; 282 … storage section; m1 … fiber stock; m2 … coarse chips; m3 … defibrinates; a first screen of M4-1 …; a second screen of M4-2 …; an M5 … first web; m6 … subdivision; a mixture of M7 …; an M8 … second web; an S … sheet; p1 … starch.