Non-hydrolyzable fiber sheet and method for producing same
阅读说明:本技术 具有非水解性的纤维片材及其制造方法 (Non-hydrolyzable fiber sheet and method for producing same ) 是由 山田菊夫 于 2019-03-29 设计创作,主要内容包括:本发明为具有非水解性的纤维片材及其制造方法。技术问题:提供一种关心环境并且兼具强度和柔软度的具有非水解性的纤维片材及其制造方法。技术方案:所述纤维片材含有天然来源的纤维原材料且具有非水解性,其具备:原纸片材,其通过气流成网制法形成;天然分解性的粘合剂,其浸含于所述原纸片材,用于粘结所述天然来源的纤维原材料;以及天然分解性的交联剂,其浸含于所述原纸片材,用于使所述粘合剂彼此交联,所述纤维片材至少在浸含有所述交联剂的状态下对所述原纸片材进行加热处理而形成。(The present invention relates to a non-hydrolyzable fiber sheet and a method for producing the same. The technical problem is as follows: provided are a fiber sheet having non-hydrolytic property, which is environmentally friendly and has both strength and softness, and a method for producing the same. The technical scheme is as follows: the fiber sheet contains a fiber raw material of natural origin and has non-hydrolyzability, and is provided with: a base paper sheet formed by an air-laid method; a naturally degradable binder impregnated into the base paper sheet for binding the naturally derived fiber raw material; and a naturally degradable crosslinking agent impregnated in the base paper sheet for crosslinking the binders to each other, wherein the fiber sheet is formed by heat-treating the base paper sheet in a state in which at least the crosslinking agent is impregnated.)
1. A non-hydrolyzable fiber sheet containing a fiber raw material of natural origin, the fiber sheet having:
a base paper sheet formed by an air-laid method;
a naturally degradable adhesive impregnated in the base paper sheet for bonding the raw material of natural origin; and
a naturally degradable crosslinking agent impregnated in the base paper sheet for crosslinking the binders to each other,
the fiber sheet is formed by heating the base paper sheet in a state that at least the cross-linking agent is impregnated.
2. A non-hydrolyzable fiber sheet characterized by using a raw material of natural origin, the fiber sheet having:
a base paper sheet formed by an air-laid method;
a naturally degradable adhesive impregnated in the base paper sheet for bonding the raw material of natural origin; and
a crosslinking agent impregnated in the base paper sheet for crosslinking the binders with each other,
the impregnation content of the crosslinking agent is less than or equal to that of the adhesive,
the fiber sheet is formed by heating the base paper sheet in a state that at least the cross-linking agent is impregnated.
3. The non-hydrolyzable fiber sheet according to claim 1 or 2,
the fiber sheet has a front surface portion, a back surface portion, and an intermediate portion formed between the front surface portion and the back surface portion,
the fiber sheet is formed such that the impregnation concentration of the binder and/or the crosslinking agent in the surface portion and the back surface portion is higher than the impregnation concentration of the binder in the intermediate portion.
4. The fiber sheet having non-hydrolyzing property according to any one of claims 1 to 3,
the fiber sheet is formed in a state where the binder and the crosslinking agent are added to the base paper sheet from a predetermined first direction and a second direction different from the first direction.
5. The fiber sheet having non-hydrolyzing property according to any one of claims 1 to 4,
the heat treatment is performed by aeration heating.
6. The fiber sheet having non-hydrolyzing property according to any one of claims 1 to 5,
the base paper sheet subjected to the heat treatment is impregnated with a softening agent.
7. The fiber sheet having non-hydrolyzing property according to any one of claims 1 to 5,
the base paper sheet subjected to the heat treatment is subjected to a cleaning treatment.
8. A method for producing a fiber sheet containing a fiber material derived from natural sources, the method comprising:
forming a base paper sheet by an air-laid method;
pressing the base paper sheet in the thickness direction;
adding a binder to the pressed base paper sheet;
adding a crosslinking agent to the base paper sheet to which the binder is added; and
and a step of heating and drying the base paper sheet to which the crosslinking agent is added.
9. The method for producing a fiber sheet according to claim 8,
and heating and compressing the base paper sheet after heating and drying.
10. The method for producing a fiber sheet according to claim 8 or 9,
the fiber sheet has a front surface portion, a back surface portion, and an intermediate portion formed between the front surface portion and the back surface portion,
the fiber sheet is formed such that the impregnation concentration of the binder and/or the crosslinking agent in the surface portion and the back surface portion is higher than the impregnation concentration of the binder in the intermediate portion.
11. The method for producing a fiber sheet according to any one of claims 8 to 10,
the adhesive and the crosslinking agent are added to the base paper sheet from a predetermined first direction and a second direction different from the first direction.
12. The method for producing a fiber sheet according to any one of claims 8 to 11,
the step of heating is performed by aeration heating.
13. The method for producing a fiber sheet according to any one of claims 8 to 12,
the heating step is followed by a step of adding a softening agent.
14. The method for producing a fiber sheet according to any one of claims 8 to 13,
the heated base paper sheet is further moistened.
15. The method for producing a fiber sheet according to claim 14,
further comprises: and a step of performing dehydration treatment for removing water contained in the wet base paper sheet.
16. The method for producing a fiber sheet according to claim 15,
the step of performing the dehydration treatment is performed by pressing the wet base paper sheet using a flat roll.
17. A non-hydrolyzable fiber sheet that uses a fiber material of natural origin, the fiber sheet comprising:
a base paper sheet formed by an air-laid method;
a naturally degradable binder impregnated into the base paper sheet for binding the naturally derived fiber raw material; and
a crosslinking agent impregnated in the base paper sheet for crosslinking the binder,
a wetting treatment is performed to wet the base paper sheet impregnated with the crosslinking agent with a liquid.
18. The non-hydrolyzable fiber sheet according to claim 17,
as for the fibers constituting the base paper sheet, gaps between fibers stacked by an air-laying method are locally compressed, and the binder is impregnated between the fibers where the gaps between the fibers are locally compressed.
19. The non-hydrolyzable fiber sheet according to claim 17 or 18,
the adhesive and/or the crosslinking agent are impregnated in the surface and the back of the base paper sheet.
20. The non-hydrolyzable fiber sheet according to any one of claims 17 to 19,
the fiber sheet has a front surface portion, a back surface portion, and an intermediate portion formed between the front surface portion and the back surface portion,
the fiber sheet is formed such that the impregnation concentration of the binder and/or the crosslinking agent in the surface portion and the back surface portion is higher than the impregnation concentration of the binder in the intermediate portion.
21. The fiber sheet having non-hydrolyzing property according to any one of claims 17 to 20,
the fiber sheet is formed in a state where the binder and the crosslinking agent are added to the base paper sheet from a predetermined first direction and a second direction different from the first direction.
22. The non-hydrolyzable fiber sheet according to any one of claims 17 to 21,
and heating the base paper sheet impregnated with the binder and/or the crosslinking agent.
23. The non-hydrolyzable fiber sheet according to claim 22,
the heat treatment is performed by aeration heating.
24. The non-hydrolyzable fiber sheet according to claim 22 or 23,
the base paper sheet subjected to the heat treatment is impregnated with a softening agent.
25. The non-hydrolyzable fiber sheet according to any one of claims 17 to 24,
the ratio of the impregnation amount of the crosslinking agent to the impregnation amount of the binder, i.e., the impregnation amount of the crosslinking agent/the impregnation amount of the binder, is in the range of 0.25 to 0.90.
26. The non-hydrolyzable fiber sheet according to any one of claims 17 to 25,
the impregnation thickness of the crosslinking agent in the base paper sheet is 0.01mm or more.
27. The non-hydrolyzable fiber sheet according to any one of claims 17 to 26,
a treatment for improving the fluidity of the adhesive is performed.
28. The non-hydrolyzable fiber sheet according to any one of claims 17 to 27,
the crosslinking agent is subjected to a treatment for preventing crystallization of the crosslinking agent.
29. The non-hydrolyzable fiber sheet according to any one of claims 17 to 28,
the wet treatment is a treatment of washing the base paper sheet and a treatment of dehydrating the base paper sheet in a state of being subjected to the washing treatment.
30. A method for producing a non-hydrolyzable fiber sheet containing a fiber material derived from natural sources, the method comprising:
forming a base paper sheet by an air-laid method;
pressing the base paper sheet in a thickness direction;
adding either a naturally degradable binder or a naturally degradable crosslinking agent to the front and back surfaces of the pressed base paper sheet;
a step of adding one of the naturally degradable binder and the naturally degradable crosslinking agent to the front surface and the back surface of the base paper sheet to which the other of the naturally degradable binder and the naturally degradable crosslinking agent is added; and
and a step of heating the base paper sheet to which at least either one of the binder and the crosslinking agent is added.
31. A method for producing a non-hydrolyzable fiber sheet containing a fiber material derived from natural sources, the method comprising:
forming a base paper sheet by an air-laid method;
pressing the base paper sheet in a thickness direction;
adding either a crosslinking agent or a naturally degradable binder to the front and back surfaces of the pressed base paper sheet;
a step of adding either one of the naturally degradable binder and the naturally degradable crosslinking agent to the front surface or the back surface of the base paper sheet to which either one of the crosslinking agent and the naturally degradable binder is added; and
a step of heating the base paper sheet to which at least either one of the binder and the crosslinking agent is added,
the impregnation content of the crosslinking agent with respect to the base paper sheet is not more than the impregnation content of the binder.
32. A method for producing a non-hydrolyzable fiber sheet containing a fiber material derived from natural sources, the method comprising:
forming a base paper sheet by an air-laid method;
pressing the base paper sheet in a thickness direction;
adding either a crosslinking agent or a naturally degradable binder to the front and back surfaces of the pressed base paper sheet;
a step of adding either one of the naturally degradable binder and the naturally degradable crosslinking agent to the front surface or the back surface of the base paper sheet to which either one of the crosslinking agent and the naturally degradable binder is added; and
and a step of wetting the base paper sheet to which the crosslinking agent is added with a liquid.
33. The method for producing a fiber sheet having non-hydrolyzing property according to any one of claims 30 to 32,
as for the fibers constituting the base paper sheet, gaps between fibers stacked by an air-laying method are locally compressed, and the binder is impregnated between the fibers where the gaps between the fibers are locally compressed.
34. The method for producing a fiber sheet having non-hydrolyzing property according to any one of claims 30 to 33,
the adhesive and/or the crosslinking agent are impregnated in the surface and the back of the base paper sheet.
35. The method for producing a fiber sheet having non-hydrolyzing property according to any one of claims 30 to 34,
the fiber sheet has a front surface portion, a back surface portion, and an intermediate portion formed between the front surface portion and the back surface portion,
the fiber sheet is formed such that the impregnation concentration of the binder and/or the crosslinking agent in the surface portion and the back surface portion is higher than the impregnation concentration of the binder in the intermediate portion.
36. The method for producing a fiber sheet having non-hydrolyzing property according to any one of claims 30 to 35,
the ratio of the impregnation amount of the crosslinking agent to the impregnation amount of the binder, i.e., the impregnation amount of the crosslinking agent/the impregnation amount of the binder, is in the range of 0.25 to 0.90.
37. The method for producing a fiber sheet having non-hydrolyzing property according to any one of claims 30 to 36,
the impregnation thickness of the crosslinking agent in the base paper sheet is 0.01mm or more.
38. The method for producing a fiber sheet having non-hydrolyzing property according to any one of claims 30 to 37,
a treatment for improving the fluidity of the adhesive is performed.
39. The method for producing a fiber sheet having non-hydrolyzing property according to any one of claims 30 to 38,
the crosslinking agent is subjected to a treatment for preventing crystallization of the crosslinking agent.
40. The method for producing a fiber sheet having non-hydrolyzing property according to any one of claims 30 to 39,
in the step of adding the binder, the binder heated from 35 ℃ to 70 ℃ is added to the base paper sheet.
41. The method for producing a fiber sheet having non-hydrolyzing property according to any of claims 30 to 40,
in the step of adding the crosslinking agent, the crosslinking agent heated from 35 ℃ to 70 ℃ is added to the base paper sheet.
42. The method for producing a fiber sheet having non-hydrolyzing property according to claim 30 or 31,
the step of heat treatment is performed by heating with ventilation.
43. The method for producing a fiber sheet having non-hydrolyzing property according to claim 30 or 31,
the base paper sheet subjected to the heat treatment is impregnated with a softening agent.
44. The method for producing a fiber sheet having non-hydrolyzing property according to claim 32,
the step of wetting the base paper sheet to which the crosslinking agent is added with a liquid is a dehydration treatment of wetting the base paper sheet and dehydrating the wet base paper sheet.
45. The method for producing a fiber sheet having non-hydrolyzing property according to claim 30 or 31,
the heated base paper sheet is further moistened.
46. The method for producing a fiber sheet having non-hydrolyzing property according to claim 44 or 45, wherein,
further comprising: and a step of performing dehydration treatment for removing water contained in the wet base paper sheet.
47. The method for producing a fiber sheet having non-hydrolyzing property according to any one of claims 44 to 46,
the step of performing the dehydration treatment is performed by pressing the wet base paper sheet using a flat roll.
Technical Field
The present invention relates to a non-hydrolyzable fiber sheet and a method for producing the same.
Background
Conventionally, a fiber sheet using biodegradable fibers has been proposed, and it has been proposed to combine hydrolyzability and hard-to-break property by adding a water-soluble inorganic salt to carboxylic acid-modified polyvinyl alcohol as a binder in the production of a sheet having hydrolyzability (patent document 1).
Drawings
Fig. 1 is an explanatory view schematically showing a plane and a cross section of a non-hydrolyzable fiber sheet of the present invention.
Fig. 2 is an explanatory view showing a process for producing a non-hydrolyzable fiber sheet of the present invention.
Fig. 3 is an explanatory view showing a second production process of the non-hydrolyzable fiber sheet of the present invention.
Fig. 4 is an external perspective view of the first pressing roller.
Fig. 5 is an external perspective view of the second pressing roller.
Detailed Description
An embodiment of the non-hydrolyzable fiber sheet of the present invention (hereinafter, simply referred to as "fiber sheet") will be described in detail. The non-hydrolyzable property means the property shown in JISP 4501. Further, in the present specification, "nature-degradable" means that the natural-degradable substance is decomposed by microorganisms, ultraviolet rays, climate change, and the like in the air, in the soil, or in the water, and thus the environmental load is reduced.
The fiber sheet of the present embodiment is a fiber sheet having non-hydrolyzability containing a fiber material of natural origin, and includes:
a base paper sheet formed by an air-laid method;
a naturally degradable adhesive impregnated in the base paper sheet for bonding a fiber raw material of natural origin; and
a naturally degradable crosslinking agent impregnated in the base paper sheet for crosslinking the adhesives with each other,
the fiber sheet is formed by heating a base paper sheet in a state of being impregnated with at least a crosslinking agent. The fibrous sheet may be produced by a dry process different from the air-laid process.
(base paper sheet)
The base paper sheet is a member to be a base fabric of a fiber sheet, and is formed by an air-laid method. The air-laid method is a method of producing a base paper sheet by subjecting a stacked body in which ground pulp or a large number of fibers mainly made of ground pulp are stacked along a downward flowing air stream to various processes such as embossing.
As a material for the base paper sheet, a fiber material of natural origin is preferable. Specifically, the base paper sheet is preferably made of pulp paper or a material mainly made of pulp, that is, a material containing a cellulose-based component. Further, the mixing of pulp is preferably 30% or more, and the mixing of pulp is more preferably 50% or more. Further, the blending of the pulp is more preferably 80% or more. By setting the blending of the pulp in this manner, the overall flexibility of the fiber sheet can be improved, or the manufacturing cost and the production efficiency can be further improved.
The pulverized pulp is pulp obtained by finely pulverizing raw material pulp, which is a raw material of paper materials and the like, into cotton by a pulverizer or the like. As a material for crushing pulp, various raw material pulps can be used. Here, the pulverized pulp refers to pulp obtained by pulverizing a pulp material into a cotton-like form. Thus, when cotton-like ground pulp is stacked in order, a space is easily formed between the fibers. Many such spaces are formed from fiber to fiber. By forming this space, the volume of the base paper sheet can be increased, and the permeability of the binder and the crosslinking agent, which will be described later, can be improved. Further, by forming the base paper sheet from cotton-like pulverized pulp by the air-laid method in this way, a space is formed between the stacked fibers, and the degree of freedom of movement of each fiber can be increased. This can improve the flexibility of the base paper sheet and also improve the production efficiency.
When pulp is used as a material for the base paper sheet, various raw material pulps can be used as the pulp used. Examples of the raw material pulp include: wood pulp, synthetic pulp, waste pulp, toilet paper material, and the like. Further, as the wood pulp, for example, pulp obtained by blending bleached kraft softwood pulp obtained from a conifer such as red pine, spruce, sakhalin fir, douglas fir, hemlock, and spruce with bleached kraft hardwood pulp obtained from a broadleaf tree such as beech, oaks, birch, eucalyptus, oak, and alder at a predetermined ratio can be used. Among them, from the viewpoint of production, it is preferable to use raw material pulp formed of bleached kraft softwood pulp. In addition, when natural fibers are used as a material for the base paper sheet, for example, kenaf, bamboo fiber, straw, cotton, cocoon fiber, sugar cane, and the like are preferably used. The above are examples, and the present invention is not limited to these examples. In the fiber sheet of the present embodiment, ground pulp or a material mainly composed of ground pulp is preferably used.
(Binder)
The binder is used to bind the raw fiber material of natural origin constituting the base paper sheet. The adhesive may be any adhesive that is naturally degradable, has a predetermined adhesive strength, and can bond the above materials with a predetermined strength. Examples of such binders include: polysaccharide derivatives, natural polysaccharides, synthetic polymers, etc., or proteins, alginic acid, chitosan, etc. Examples of polysaccharide derivatives include: carboxymethyl cellulose (CMC), carboxyethyl cellulose, carboxymethylated starch or a salt thereof, starch, methyl cellulose, ethyl cellulose, and the like. Examples of the natural polysaccharides include: guar gum, tragacanth gum, xanthan gum, sodium alginate, carrageenan, gum arabic, gelatin, casein, and the like. Further, examples of the synthetic polymer include: polyvinyl alcohol (PVA), ethylene-vinyl acetate copolymer resin (EVA), polyvinyl alcohol derivatives, and polymers or copolymers of unsaturated carboxylic acids, salts thereof, and the like, and examples of the unsaturated carboxylic acids include: acrylic acid, methacrylic acid, maleic anhydride, maleic acid, fumaric acid, and the like. Among them, carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVA) are particularly preferable. These binders may be used alone, or two or more thereof may be mixed and used in combination. As the binder used for the fiber sheet of the present embodiment, preferred are: biodegradable resins such as polycaprolactone, polyhydroxyalkanoate, polyhydroxybutyrate, polylactic acid, and esterified starch, biodegradable resins such as cellulose acetate, polyethylene succinate, polyvinyl alcohol, polyglycolic acid, chitosan/cellulose/starch, poly (hydroxybutyrate/hydroxyhexanoate), poly (caprolactone/butylene succinate), polybutylene succinate, poly (butylene succinate/adipate), poly (butylene succinate/carbonate), poly (ethylene terephthalate/succinate), poly (butylene adipate/terephthalate), and poly (tetramethylene adipate/terephthalate), and biodegradable resin mixtures; a naturally degradable binder such as a biodegradable biomass resin.
The CMC may be an ammonium salt, a sodium salt, a potassium salt, or the like. Among these CMCs, CMC ammonium has a property of being heated, that is, crosslinked, so-called self-crosslinking. Thus, when CMC ammonium is used as the binder, the impregnation amount of the crosslinking agent can be reduced or the crosslinking agent is not impregnated as compared with the case where other kinds of CMC are used as the binder. Further, among the PVAs, there are a PVA that requires a crosslinking agent and a PVA that does not require a crosslinking agent, and therefore, when the PVA that does not require a crosslinking agent is used as a binder, the PVA may not be impregnated with the crosslinking agent.
(crosslinking agent)
The crosslinking agent is an agent that causes a crosslinking reaction with the binder to form a crosslinked structure in the binder. The crosslinking agent of the present embodiment is preferably a crosslinking agent having natural degradability. For example, when a binder having a carboxyl group such as carboxymethyl cellulose (CMC) is used, it is preferable to use a polyvalent metal ion having a valence of 2 or more. Examples of the polyvalent metal ion include: metal ions such as magnesium, calcium, titanium, manganese, iron, cobalt, nickel, copper, zinc, aluminum, silver, tin and the like. Further, as the compound for supplying the polyvalent metal ion, one kind of or any combination of two or more kinds of aluminum hydroxide, aluminum chloride, aluminum sulfate, dihydroxyaluminum aminoacetate, kaolin, aluminum stearate, aluminum magnesium hydroxide, aluminum potassium sulfate (also known as alum), aluminum magnesium metasilicate, aluminum glycinate, aluminum magnesium metasilicate, aluminum nitrate, aluminum sulfate, aluminum acetate, aluminum hydroxide ferrous sulfate, ferrous chloride, zinc sulfate, copper chloride, tin chloride, silver nitrate, and the like can be used alone. In the fiber sheet of the present embodiment, alum and copper sulfate are particularly preferably used. Examples of alum include sodium aluminum alum, potassium alum, ammonium alum, sodium chromium alum, potassium chromium alum, ammonium chromium alum, sodium iron alum, potassium iron alum, and ammonium iron alum. As alum in the present embodiment, colorless alum is preferable, and therefore, sodium alum, potassium alum, and ammonium alum are preferably used. For example, when ammonium alum is used as alum, the concentration of the ammonium alum solution is preferably about 1% to 20%, and the temperature of the ammonium alum solution is preferably maintained at 10 ℃ to 60 ℃ so as not to crystallize.
(concentration distribution of Binder and crosslinking agent in base paper sheet)
Next, the concentration distribution of the binder and the crosslinking agent in the base paper sheet will be described with reference to fig. 1. Fig. 1(a) is an explanatory view for explaining concentration distributions of the binder and the crosslinking agent in the base paper sheet when viewed in plan view. Fig. 1(b) is an explanatory view for explaining the concentration distribution of the binder and the crosslinking agent at the cross section of the section a-a in fig. 1 (a). In fig. 1(a), the front side of the base paper sheet is referred to as the front side, and the back side of the base paper sheet is referred to as the back side.
As shown in fig. 1(a), the base paper sheet 1 is a long body having a long direction x and a short direction y in a plan view. The binder and the crosslinking agent impregnated in the base paper sheet 1 of the present embodiment are added to the base paper sheet 1 by spraying the base paper sheet 1 with a jet sprayer, for example. In fig. 1(a), reference numeral 2 denotes the position of a nozzle for ejecting the adhesive and the crosslinking agent to the front surface of the base paper sheet 1, and reference numeral 3 denotes the position of a nozzle for ejecting the adhesive and the crosslinking agent to the back surface of the base paper sheet 1. The nozzles for ejecting the adhesive and the crosslinking agent are generally disposed independently of each other, but here, for convenience of explanation, the position of the nozzle for ejecting the adhesive and the position of the nozzle for ejecting the crosslinking agent are described as the same position.
As shown in fig. 1a, two rows of ejection nozzles are arranged in the longitudinal direction x on the front surface side (see reference numeral 2 in fig. 1 a) and two rows of ejection nozzles are arranged in the longitudinal direction x on the back surface side (see reference numeral 3 in fig. 1 a) of the base paper sheet 1. The positions of the two rows of the ejection nozzles are alternately arranged on the near side and the far side so as to be near side, far side, and near side with respect to the x direction as they move forward in the y direction. That is, the positions of the ejection nozzles are arranged in a staggered pattern. Thereby, the adhesive and the crosslinking agent ejected from the ejection nozzle have a uniform concentration with respect to the base paper sheet 1.
As shown in fig. 1(b), the concentration distributions of the binder and the crosslinking agent are different in the z direction of the base paper sheet 1. That is, when the front surface portion 5 positioned above the intermediate portion 4 in the z direction and the back surface portion 6 positioned below the intermediate portion 4 of the base paper sheet 1 are separated, the impregnation concentration of the binder and the crosslinking agent in the front surface portion 5 and the back surface portion 6 is higher than the impregnation concentration of the binder and the crosslinking agent in the intermediate portion 4. In the front surface portion 5 and the back surface portion 6, the above-mentioned impregnation concentration decreases in order from the end portion near the front surface or the back surface toward the end portion near the center portion 4. When the impregnation concentration of the binder and the impregnation concentration of the crosslinking agent are compared, the impregnation amount of the crosslinking agent is preferably equal to or less than the impregnation amount of the binder. In this way, the crosslinking agent which does not contribute to crosslinking due to excessive addition of the crosslinking agent can be reduced.
When the impregnation concentration of the binder and the impregnation concentration of the crosslinking agent are compared, the impregnation concentration of the crosslinking agent is preferably lower than the impregnation concentration of the binder.
As will be described later, the base paper sheet 1 thus formed is subjected to a heat treatment in a state of being impregnated with a binder and a crosslinking agent. By performing the heat treatment in this manner, the crosslinking reaction of the binder for bonding the raw materials constituting the base paper sheet and the crosslinking agent for crosslinking the binder with each other can be promoted, the bonding of the fibers with each other can be further increased, and the bonding strength can be greatly improved. The heating is preferably a ventilation heating in which hot air is circulated in a chamber having a predetermined size. Further, the base paper sheet 1 is preferably a base paper sheet in a state in which a softening agent is impregnated in a heat-treated state.
Further, the base paper sheet 1 is preferable in that softness can be further obtained by washing the base paper sheet in a heat-treated state or a state in which the base paper sheet is impregnated with a softening agent. When cleaning the base paper sheet 1, it is preferable to perform cleaning using a liquid such as water.
The fiber sheet of the present embodiment is impregnated with the crosslinking agent in a state of being impregnated with the binder, and is further subjected to a heat treatment, so that a fiber sheet having both softness and strength can be obtained.
Next, a modified example of the fiber sheet of the present embodiment will be described. In the fiber sheet of the present modification, the base paper sheet 1 in a heat-treated state is subjected to softening treatment. The softening treatment is performed by applying a softening agent. Examples of the softening agent used herein include: propylene glycol, butylene glycol, dipropylene glycol, liquid paraffin, and the like. By performing softening treatment using such a softening agent, the hardness of the fiber sheet 1 can be softened, and a fiber sheet having both strength and softness can be obtained.
(embodiment of the production Direction of the fiber sheet of the present invention)
Next, an embodiment of the method for producing a fiber sheet of the present invention will be described with reference to fig. 2. In the present embodiment, the raw material (material), basis weight, applicable binder and crosslinking agent, drying method, and the like of the fiber sheet are not described.
Fig. 2 schematically shows a production line 100 for a
In the production line 100, the pulp raw material roll, which is a natural-origin fibrous material, is pulverized by the pulverizing
In the production line 100, the pulp fibers in a string form are stacked in a stacking step by the stacking
The pulverized pulp accumulated in the stacking
The conveying net 109 conveys the base paper sheet in a conveying direction (a direction a in fig. 2) by a driving force transmitted from a driving source (not shown). A
Next, in the production line 100, the stacked sheets are pressed by a plurality of pressing devices in a pressing process following the stacking process. In the present embodiment, the pressing step is performed using a pair of flat rollers, not shown, and the bulk of the stacked sheet is adjusted by pressing the stacked sheet. In the pressing step, since the conveying net 109 is pressed together with the stacked sheet, the mesh pattern of the conveying net 109 is printed on the surface of the stacked sheet in contact with the conveying net 109 during pressing.
In the adhesive coating step following the pressing step, an adhesive is added to the stacked sheets. In the present embodiment, the adhesive coating step includes a first adhesive coating step and a second adhesive coating step, and a first drying step described later is interposed between the first adhesive coating step and the second adhesive coating step. Here, first, the first adhesive application step will be described.
In the first adhesive agent application step, a
The
In the production line 100, a first drying step, which is one of the drying steps, is performed next to the first adhesive coating step. In the first drying step, hot air drying using hot air is performed in the
In the production line 100, a second adhesive coating step is performed following the first drying step. In the second adhesive agent application step, a
The
As described above, in the method for producing a fiber sheet according to the present embodiment, since the first adhesive agent application step and the second adhesive agent application step are provided, the adhesive agent can be applied to the upper surface and the lower surface of the stacked sheet without turning the stacked sheet upside down. This makes it possible to speed up the conveyance of the stacked sheets without complicating the production line 100.
In the first adhesive agent application step and the second adhesive agent application step, when the diffusion preventing cover for the adhesive agent is attached to form the closed space, and the adhesive agent not applied to the stacked sheet is recovered by a pump or the like and supplied again to the
In the production line 100, a second drying step, which is one of the drying steps, is performed next to the second adhesive application step. In the second drying step, hot air drying using hot air is performed in the
In the production line 100, a crosslinking agent coating step is performed following the second drying step. In the crosslinking agent application step, the crosslinking
The crosslinking
In the production line 100, a third drying step, which is one of the drying steps, is performed following the crosslinking agent application step. In the third drying step, hot air drying using hot air is performed in the
By producing a fiber sheet by such a production method, the fiber sheet of the present embodiment can be efficiently produced.
Next, a modified example of the method for producing a fiber sheet according to the present embodiment will be described. In this modification, a softening step may be added in addition to the steps of the method for producing a fiber sheet of the above embodiment. In the softening step, for example, a softener (e.g., glycerin) may be applied by a sprayer, or the softener may be added to the stacked sheet by printing or the like. Further, the dried stacked sheet may be rewetted with water or the like, the water may be dehydrated (removed), and further, the sheet may be reheated while being pressed with a heated flat roll or the like. Alternatively, the crosslinking agent may be applied after the adhesive is applied, and then dried.
As described above, the
Next, a
The
In the present embodiment, in the pressing step, the
In the present embodiment, the third drying step by the
In the production line 100 and the
Further, as a method of supplying the binder and the crosslinking agent, there can be mentioned: spraying with a sprayer, coating with a roll coater or brush, or dipping in a binder or a crosslinking agent. As the sprayer, there are a one-fluid sprayer and a two-fluid sprayer, and the one-fluid sprayer and the two-fluid sprayer can be used for spraying the crosslinking agent, but in the case of spraying a binder such as CMC having a high viscosity, a one-fluid type is preferable. When a fluid type sprayer is used, since the pressure can be directly applied to the binder and the crosslinking agent and the spraying can be performed, the loss due to scattering of the binder and the crosslinking agent is small, and the impregnation rate can be improved.
The
The structure is as follows: the operation of immersing the
In the cleaning apparatus 400 thus formed, the
The
In the present embodiment, a method of wetting the
The material of the various rollers such as the
After the washing step, salts, acids, dirt, paper powder (unfixed ground pulp, etc.) and the like contained in the
The wet treatment of the
When the surface treatment is performed before the wet-treated fiber sheet is transferred to the softening treatment step by the embosser roller, the fiber sheet can be further dried and the smoothness of the sheet surface can be improved. In the
Next, the back side of the sheet is contacted with a
In the
The
As described above, the elasticity of the
In the
The
With the method for producing a fiber sheet according to the present embodiment, a soft fiber sheet having a good texture and being less likely to break can be easily produced.
Description of the symbols
1 base paper sheet
100 production line
101 fiber sheet
103 pulp blank roll
106 crushing device
107 stacking device
109 net for transportation
121 first coating device
124 first drying device
130 second coating device
133 second drying device
140 cross-linking agent coating device
150 third drying device
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