JP6616082B2 - Water-degradable pulp pile sheet and method for producing water-degradable pulp pile sheet - Google Patents

Description

  The present invention relates to a hydrolyzable pulp fiber sheet that can be used as a cleaning article such as a wet tissue, and a suitable method for producing the same.

  Some wet tissues are composed of a first layer made of a tissue web containing cellulose fibers and a second layer made of an airlaid nonwoven web (see Patent Document 1, Claims, and Claim 11).

  In the thing of this patent document 1, the 1st layer (obtained by papermaking), the 2nd layer (obtained by the airlaid method) from which this differs, and the binder which integrates both are required. The first layer provides strength to the wet tissue but reduces its flexibility.

US Pat. No. 8,257,553

  The main problems to be solved by the present invention are that it can be produced without going through the paper making process, and the shape is maintained without having a laminate with the paper made hydrolyzed paper. The present invention provides an efficient method for producing a water-decomposable pulp-developing sheet having water properties and a water-degradable pulp-developing sheet that is suitably produced and has an appropriate strength and excellent water-degradability.

In order to solve the above problems, the present invention is configured as follows. That is, the present invention
<1> On at least one surface of the raw fiber sheet in a non-wet state made of pulverized pulp or mainly pulverized pulp,
1 to 10% by weight of binder (A) having a carboxyl group;
0.25 to 2.5% by weight of binder (B) having a group represented by the following formula (1) as a basic polymerization unit;
A binder supplying step for supplying a binder liquid prepared by blending,
After the binder supply step, a drying step of drying the raw fiber sheet,
It is a manufacturing method of the hydrolysable pulp fiber sheet characterized by having.
Equation _{(1): - [CH 2} -CHX] -
However, in Formula (1), X represents at least one of a hydrogen element, a hydroxyl group, and an acetate group.

<2> The water-degradable pulp product according to <1>, wherein in the binder supply step, a content ratio (weight ratio) ((A) / (B)) in the binder liquid is 1/1 to 8/1. It is a manufacturing method of a textile sheet.
<3> The method according to <1> or <2>, wherein the binder liquid is applied to both surfaces of the raw fiber sheet in the binder supply step.
<4> The method for producing a hydrolyzable pulp fiber sheet according to any one of <1> to <3>, wherein (A) and (B) are compatible with each other.

<5> (A) is carboxymethyl cellulose, (B) is polyvinyl alcohol, and the blending temperature when preparing the binder liquid is 50 ° C. or higher, according to any one of <1> to <4>. This is a method for producing a water-degradable pulp pile sheet.
<6> At least 1.5 to 15% by weight of (A) a binder having a carboxyl group and (B) represented by the following formula (1) in a raw fiber sheet made of pulverized pulp or mainly pulverized pulp and not wet. A hydrolysable pulp pile fiber sheet, which is formed by applying 0.5 to 6.0% by weight of a binder having a group as a basic polymerization unit and drying.
Equation _{(1): - [CH 2} -CHX] -
However, in Formula (1), X represents at least one of a hydrogen element, a hydroxyl group, and an acetate group.

<7> Furthermore, it is the water-decomposable pulp stacking sheet according to <6>, further including a liquid-permeable surface sheet layer.
<8> The water-decomposable pulp pile fiber sheet according to <6> or <7>, wherein (A) is carboxymethylcellulose.
<9> The hydrolysable pulp pile fiber sheet according to any one of <6> to <8>, wherein (B) is polyvinyl alcohol.
<10> The water-decomposable pulp pile fiber sheet according to any one of <6> to <9>, further impregnated with a cleaning liquid and in a wet state.

<11> The hydrolytic solution according to <10>, wherein the cleaning liquid contains 10 to 40% by weight of a water-soluble organic solvent and 2.0% to 4.5% by weight of a divalent metal salt. It is a synthetic pulp pile fiber sheet.
<12> The water-decomposable pulp pile fiber sheet according to <10> or <11>, wherein the cleaning liquid contains a feel improver.
<13> The above-mentioned <12>, wherein the feel improving agent is at least one selected from talc, boron nitride, polyethylene, (dimethicone / divinyldimethicone / silsesquioxane) crosspolymer, silica, and mica. The water-decomposable pulp pile fiber sheet described in 1.

  According to the present invention, a pulp pile fiber sheet that can be produced without going through a papermaking process, maintains its shape without forming a laminate, has an appropriate strength, and is excellent in water disintegration, is efficiently produced. It is possible to provide a production method that can be produced, and a water-decomposable pulp-laden fiber sheet that is suitably produced by the production method and has an appropriate strength and excellent water-degradability.

It is process drawing for demonstrating the manufacturing method of the water-degradable pulp fiber sheet concerning one Embodiment of this invention. It is process drawing for demonstrating the method to manufacture the water-degradable pulp fiber sheet concerning one Embodiment (2nd example) of this invention.

  Hereinafter, a typical embodiment of the present invention will be described with reference to FIGS. 1 and 2. The water-decomposable pulp stacking sheet according to this embodiment includes a raw fiber sheet, and is typically suitable for use as a water-degradable pulp stacking sheet used as a cleaning sheet such as a wet wipe.

-Manufacturing method of pulp fiber sheet-
Drawing 1 is a flowchart for explaining a manufacturing method of a water-degradable pulp fiber sheet concerning one embodiment (the first example) of the present invention. However, the embodiment described here is merely an example when the present invention is implemented, and the present invention is not limited to what is described in the following embodiment.

(Preparation of raw fiber sheet)
In FIG. 1, the raw material sheet supply unit 10 is a feed roll around which the raw material sheet 1 is wound. The raw material sheet 1 is sent out in the direction of arrow X from the raw material sheet supply unit 10 and fed into the pulverization unit 20.

The raw material sheet 1 may be a single-layer structure composed of a single thin paper such as toilet paper, or may be a multilayer structure in which a plurality of thin papers are stacked.
The raw material sheet 1 contains raw material pulps, such as a wood pulp, a synthetic pulp, a used paper pulp, for example. Toilet paper material can be used as the raw material pulp.
Toilet paper materials can be obtained from softwood bleached kraft pulp obtained from conifers such as red pine, Ezo pine, todo pine, Douglas fir, hemlock, and spruce, and from broadleaf trees such as beech, oak, hippopotamus, eucalyptus, oak, poplar, and alder. Raw material pulp obtained by blending hardwood bleached kraft pulp at a predetermined ratio can be used.

In addition, the raw material sheet 1 is not limited to natural fibers such as pulp, and regenerated fibers such as rayon can also be used. Natural fibers and regenerated fibers can be mixed and used, but natural fibers can be used. preferable. The raw material sheet 1 may contain, for example, kenaf, bamboo fiber, cocoon, cotton, silk thread, sugar cane and the like as natural fibers other than pulp.
Note that the paper material used for the raw material sheet 1 may have water decomposability or may not have water decomposability.

The raw material sheet 1 is composed of an aggregate of a large number of fibers and has water absorption.
Since the fiber length of the softwood bleached kraft pulp is longer than that of the hardwood bleached kraft pulp even after pulverization, the fiber sheet 2 using the pulverized pulp obtained from the softwood bleached kraft pulp increases the degree of entanglement between the fibers. , The strength is improved.
In addition, the inter-fiber space volume due to the entanglement between the fibers becomes larger than when hardwood bleached kraft pulp or the like having a short fiber length is used, and the degree of freedom of movement of each fiber is increased, so that flexibility is also improved.

  The pulverization unit 20 includes a housing 21, a pulverizer 22 disposed inside the housing 21, and an airflow forming unit 23 that sucks air inside the housing 21 to form an airflow. The raw material sheet 1 supplied from the raw material sheet supply unit 10 is sent into the housing 21 and pulverized by a pulverizer 22 to obtain raw material fibers 1a made of pulverized pulp or mainly pulverized pulp.

The conveyor belt 6 is provided with a plurality of openings through which airflow can pass, and the airflow forming unit 23 is disposed below the conveyor belt 6 and sucks air through the openings.
The raw fiber 1a (pulverized pulp or the like) obtained by pulverization is in the housing 21 while the entanglement between the fibers is released and the entanglement is weakened, and the surface direction of the transport belt 6 (Y direction in the figure). And is sucked onto the conveyor belt 6 and stacked while being sequentially compressed.

  In this way, the raw fiber 1a is stacked on the conveyor belt 6 in the housing 21 of the pulverizing unit 20, and is sent out as the raw fiber sheet 2 to the outside of the pulverizing unit 20 while moving in the X direction.

  In the present embodiment, the air flow is formed in the housing 21 by suction by the air flow forming portion 23, and the raw fibers 1a are stacked on the transport belt 6 in a compressed state. The method of stacking the raw fiber 1a on the belt 6 is not limited to this.

  Moreover, in this embodiment, although the raw fiber 1a was directly piled on the conveyance belt 6, when forming the pulp pile fiber sheet of the aspect which provides a surface sheet layer further, for example, as mentioned later, in a manufacturing process, For example, a surface sheet layer may be provided on the conveyor belt 6 and the raw fiber 1a may be stacked thereon to form a pulp stacking layer.

(Compression and pressing process)
In FIG. 1, the compression / pressing unit 30 compresses and presses the raw fiber sheet 2 with a roll 31. The roll 31 has an embossing roll 31a as an upper roll and a flat roll 31b as a lower roll. The embossing roll 31 a has a concave shape, a convex shape, or a concave-convex shape (hereinafter collectively referred to as a “concave (emboss)” shape) in the direction perpendicular to the conveying direction X with respect to the raw fiber sheet 2. It can be formed. In other words, “unevenness (embossing)” is not limited to the case where the concave portions and the convex portions are formed at substantially the same interval, but when the convex portions are formed on the flat portion, or the concave portion is formed on the flat portion. It includes the case where is formed. Furthermore, the case where the convex part and the recessed part are formed in the flat part is also included.

  In addition, the shape of each pattern of “unevenness (emboss)” may be a circle, an ellipse, a triangle, a quadrangle, a rhombus, and the like, and other shapes such as a pattern pattern or a linear protrusion A corrugated shape in which a portion and a recess are repeatedly formed may be used. Further, the unevenness may be formed over the entire surface of the raw fiber sheet 2 or may be formed only in part. Furthermore, the uneven | corrugated formation by embossing may be performed only with respect to the single side | surface from either one of the raw material fiber sheet 2, and may be performed with respect to the front and back both surfaces of the raw material fiber sheet 2, for example.

In the present embodiment, in the compression / pressing step, the roll 31 has an embossing roll as an upper roll and a flat roll as a lower roll. There is no particular limitation as long as an appropriate compression / pressing process can be performed on the sheet 2, and any known pair of rolls can be used.
For example, the upper and lower embossing rolls may be compressed and pressed by an embossing roll that forms unevenness (embossing) in the direction perpendicular to the conveyance direction X with respect to the raw fiber sheet 2. Moreover, a flat roll may be sufficient as upper and lower sides. In addition, a pair of rolls or the like for point stopping may be used.
The flat roll has a substantially flat surface and is not limited to a smooth surface. Specifically, the flat roll includes those having a concave or convex shape such as a lattice shape, a grain shape, or a satin shape on the surface thereof.

  When the raw fiber sheet 2 passes between the pair of rolls in the compression / pressing unit 30, the raw fiber sheet 2 is subjected to a pressing force having a component in the normal direction with respect to the surface, and is appropriately compressed by the rolls 31a and 31b. The raw fiber sheet 2 that has been pressed is formed.

  In this embodiment, in the compression / pressing step, the raw fiber sheet 2 is in a non-wetting state, and the compression / pressing step is performed on the raw fiber sheet 2 in a non-wetting state. Here, the “non-wet state” means that it does not include an aspect in which moisture is supplied to the raw fiber sheet 2 by spraying water on the raw fiber sheet 2 or the like. Normally, paper materials contain moisture (moisture) according to the temperature and humidity conditions, but this moisture (moisture) is not actively supplied from the outside, so it contains such moisture (moisture). However, it corresponds to the non-wetting state referred to in the present embodiment.

Therefore, although the content rate of the moisture (water | moisture content) contained in the raw material fiber sheet 2 also changes with temperature and humidity conditions, whatever the content rate is, it corresponds to the non-wet state referred to in the present invention. The raw fiber sheet 2 is compressed and pressed in a wet state impregnated with the binder liquid 4 by subjecting the raw fiber sheet 2 to compression and pressing in a normal dry and non-wet state in the atmosphere. There is no possibility that 2 adheres to the roll.
Therefore, it is not necessary to apply a release agent to a roll or the like or to apply a release agent to the raw fiber sheet 2.

(Binder supply process)
In the binder supplying step, at least one surface of the raw fiber sheet 2 is 1 to 10% by weight of the binder (A) having a carboxyl group and a group represented by the following formula (1) is one of the basic polymerization units. A binder liquid containing 0.25 to 2.5% by weight of the binder (B) having the above is supplied and applied.
Equation _{(1): - [CH 2} -CHX] -
In formula (1), X represents at least one of a hydrogen element, a hydroxyl group, and an acetic acid group.

Examples of the binder (A) having a carboxyl group include carboxymethyl cellulose (CMC), carboxymethyl cellulose, carboxymethyl C ₂ -C ₃ alkyl cellulose such as carboxymethyl ethyl cellulose, carboxymethylated starch or salts thereof, arginic acid, and the like. And polysaccharide derivatives thereof. These may be used alone or in combination of two or more. As the binder (A) having a carboxyl group, it is preferable to use carboxymethyl cellulose (CMC) from the viewpoint that an appropriate strength can be given by the obtained pulp pile fiber sheet.

  Examples of the binder (B) having a group represented by the above formula (1) as one of the basic polymerization units include polyvinyl alcohol (PVA), ethylene-vinyl acetate copolymer, vinyl acetate polymer, and the like. These may be used alone or in combination of two or more. For example, when carboxymethyl cellulose (CMC) is used as (A), it is preferable to use polyvinyl alcohol (PVA) as (B) from the viewpoint of excellent compatibility. In particular, by using PVA, it is possible to give a soft texture to the obtained pulp pile fiber sheet.

  Here, “compatible” refers to mixing at a molecular level when two or more polymer chains are mixed. Here, in addition to the compatibility in which the polymer chains are completely mixed at the molecular level, it also includes the partial compatibility in which a part of the polymer chains are mixed. Examples of the evaluation method of “compatibility” include known methods such as a visual turbidity method and a method of detecting a melting peak of a crystalline region by DSC (differential scanning calorimeter) measurement.

  The content ratio (weight ratio ((A) / (B))) in the binder liquid of (A) and (B) is not particularly limited, but is preferably 1/1 to 8/1. Is preferably 1.5 / 1 to 6/1 By adjusting the content ratio (weight ratio ((A) / (B)) within this numerical range, the advantages of using (A) and Both advantages of using (B) are drawn out, and a water-degradable pulp pile fiber sheet having both advantages is obtained.

  In particular, by blending a binder liquid containing polyvinyl alcohol (PVA) and carboxymethyl cellulose (CMC) in a weight ratio of 1/1 to 1/4, and supplying (coating) this as a binder liquid, Advantages of using carboxymethylcellulose (CMC) as a binder (improvement of strength of the resulting pulp stacking sheet, etc.) and advantages of using polyvinyl alcohol (PVA) as a binder (obtained stacking sheet) Improved flexibility and refreshing feeling). Thereby, the pulp fiber sheet which was able to combine both advantages effectively and was excellent in water decomposability is obtained.

  Moreover, when preparing a binder liquid by mix | blending polyvinyl alcohol (PVA) and carboxymethylcellulose (CMC), it is preferable to adjust so that it may become 50 degreeC or more as temperature of mixing | blending (temperature of a binder liquid). As another aspect, it is preferable to adjust so that it may become 55 degreeC or more. Furthermore, as another aspect, it is preferable to adjust so that it may become 60 degreeC or more. Although a detailed reason is unknown at this time, it is thought that the compatibility of both polymers improves more by mix | blending at said temperature. As a result, a water-decomposable pulp pile fiber sheet that effectively combines the advantages of using both polymers as a binder and is excellent in water decomposability can be obtained.

  In FIG. 1, the binder liquid supply unit 40 includes a spray-type binder liquid spraying device 41. The binder liquid spraying device 41 sprays the binder liquid 4 from the nozzle onto the surface of the raw fiber sheet 2.

  In this embodiment, the binder liquid 4 (containing (A) and (B)) is sprayed from one spray sprayer and applied. In another embodiment, the binder coating liquid containing the binder (A) and the binder coating liquid containing the binder (B) are sprayed and sprayed on the raw fiber sheet 2 from separate nozzles at substantially the same time. It may be applied to the sheet 2. Furthermore, as another embodiment, the binder coating liquid containing the binder (A) and the binder coating liquid containing the binder (B) are sprayed onto the raw fiber sheet 2 from separate nozzles in this order or in the reverse order. It is also preferable to apply by spraying. Furthermore, in order to spray a binder liquid on the surface, you may spray from the back surface of the raw material fiber sheet 2, and you may spray from both surfaces.

In the fiber pile sheet, it is preferable that a crosslinked binder is contained because physical strength is further improved. The cross-linking agent that cross-links the binder liquid 4 causes a cross-linking reaction with the binder liquid 4 to make the binder liquid 4 a cross-linked structure, thereby improving the physical strength.
Since a binder having a carboxyl group is used as the crosslinking agent, it is preferable to use a polyvalent metal ion. Examples of the polyvalent metal ion include divalent metal ions such as zinc, calcium and barium. Metal ions such as alkaline earth metals, magnesium, aluminum, manganese, iron, cobalt, nickel and copper. Among these, ions of zinc, calcium, barium, magnesium, aluminum, iron, cobalt, nickel, copper, and the like are preferably used. These are preferable in terms of imparting sufficient wet strength.

The above-mentioned polyvalent metal ions as the crosslinking agent are used in the form of water-soluble metal salts such as sulfates, chlorides, hydroxides, carbonates and nitrates.
Moreover, when polyvinyl alcohol is also contained as the binder liquid 4, a titanium compound, a boron compound, a zirconium compound, a compound containing silicon, or the like can be used as the crosslinking agent, and one or more of these compounds can be used. Can be mixed and used as a crosslinking agent. Examples of the titanium compound include titanium lactate and titanium triethanolamate, and examples of the boron compound include borax and boric acid. Examples of the zirconium compound include ammonium ammonium carbonate, and examples of the compound containing silicon include sodium silicate.

  In the present embodiment, the spray spray is used as the means for supplying the solution of the binder liquid 4 to the raw fiber sheet 2, but the binder liquid 4 can be supplied as the means for supplying the solution of the binder liquid 4. As long as there is no particular limitation, known appropriate coating means can be appropriately used. However, here, as described above, the raw fiber sheet 2 is a stacked body formed by, for example, pulverizing pulp sequentially stacked on the conveyor belt 6 under suction conditions and press-molded. From this point of view, at this point of time, the supply means for the binder liquid 4 to the raw fiber sheet 2 is a supply means that does not apply a mechanical burden (tension or the like) to the raw fiber sheet 2 as much as possible. preferable. From this viewpoint, it is preferable to apply the binder liquid 4 to the raw fiber sheet 2 in a non-contact manner by spraying or the like as in the present embodiment.

In the binder supply step 5, it is also preferable to apply the binder liquid 4 to both sides of the raw fiber sheet 2 using at least two spray sprayers on the raw fiber sheet 2. This is due to the following reason. That is, the raw fiber sheet 2 has a low inter-fiber adhesion particularly in the thickness direction and a large number of voids, as compared with, for example, a paper sheet that has undergone a general paper making process. For this reason, even if the binder liquid 4 is supplied by spray spraying from one side to the fiber stack by one sprayer, a large amount of the binder liquid 4 is required to permeate the binder liquid 4 over the entire thickness direction of the raw fiber sheet 2. Is not efficient. In this regard, the binder liquid 4 can be more efficiently permeated throughout the thickness direction of the raw fiber sheet 2 by applying the binder from both sides of the raw fiber sheet 2 by spray coating.
On the other hand, as another method, as will be described later, after the drying step, for example, when a binder supply step by a gravure printing machine is provided, at this point, it is sufficiently impregnated throughout the thickness direction. There is no need to spray and supply an amount of binder liquid by spraying.

  When a crosslinking agent for the binder liquid 4 is added as necessary, the crosslinking agent can be supplied at the same time as the binder liquid 4, but the crosslinking agent is not limited to being supplied together with the binder liquid 4, but at any point in the manufacturing process. Can be supplied and added.

(Drying process)
In the drying step, the raw fiber sheet 2 is dried after the binder supplying step. In FIG. 1, the drying unit 50 is a conventionally known drying unit such as a near infrared ray, far infrared ray infrared dryer, hot air dryer, electromagnetic wave dryer, gas dryer, drum dryer, hot roll dryer, or the like. Machine 51 is provided. From the viewpoint of drying more efficiently, electromagnetic wave drying, drying with near infrared rays or far infrared rays, and the like are preferable. The raw fiber sheet 2 supplied with the binder liquid 4 is sent to a dryer 51 and dried. In addition, in drying the raw fiber sheet 2 impregnated with the binder liquid 4 with the dryer 51, the present invention is not limited to the case of drying with one dryer 51, and by installing a plurality of dryers, You may make it dry, sending the raw material fiber sheet 2 to each dryer 51. FIG. Moreover, in order to perform the heat processing according to the kind and application quantity of the applied binder liquid, and other purposes, a plurality of types of dryers may be used in combination. For example, a combination of electromagnetic wave drying and infrared drying may be used.

(Further binder supply process (gravure printing, etc.))
In this embodiment, you may provide the further binder supply process as needed. The means for further supplying the binder is not particularly limited, and the above-described spray sprayer can be suitably used. However, from the viewpoint of allowing the binder liquid to penetrate the raw fiber sheet 2 uniformly and sufficiently, supply by gravure printing or the like is also possible. preferable. The gravure printing roll to be applied may be composed of, for example, a gravure cylinder, a pressure roller, a binder solution reservoir, a doctor blade, and the like. Thus, by providing the further binder supply process, application | coating can be performed efficiently and uniform binder application | coating is also possible from the point of thickness. Thereby, the pulp fiber sheet which is excellent also in an intensity | strength and a touch feeling can be manufactured stably and efficiently.

  In the gravure printing, the gravure cylinder is not particularly limited, but a pattern of small concave depressions (so-called “cells”) such as a lattice shape, a grain shape, and a satin texture is formed on the surface. preferable. However, even if the cylinder surface is a smooth surface, a mirror surface, etc., it can be suitably used in the present invention. However, as described above, when a cell is formed in the cylinder, the binder liquid is appropriately applied to the cell. Adhering and more effective transfer to the raw material fiber sheet 2 or the like to be applied is possible.

  In the gravure printing, the pressure roller is not particularly limited, and a generally known resin roll or the like is preferably used. The pressure roller, like the cylinder, is preferably formed with a pattern of small concave depressions (so-called “cells”) such as a lattice shape, a grain shape, and a satin surface on the surface thereof. However, even if the surface of the pressure roller is a smooth surface, a mirror surface, etc., it can be used in the present invention. However, as described above, when a pattern such as a cell is formed on the pressure roller, the material to be applied is applied. Effective transfer to the fiber sheet 2 is possible.

  In addition, also in the further binder supply process, the application | coating process of the binder liquid 4 may be performed to both surfaces of the raw material fiber sheet 2, respectively. For example, the binder liquid 4 may be sufficiently supplied and applied to each side of the sheet by performing gravure printing twice during the process. In this case, for example, after the coating process is performed on one side of the sheet, the coating process may be reversed and the coating process may be performed again.

  By the further binder supply process described above, the binder liquid 4 can be applied to and permeated into the sheet more uniformly and sufficiently. Therefore, even if a smaller amount of the binder solution is used, a pulp fiber sheet having a practically sufficient strength is provided.

(Further drying process)
In this embodiment, you may have a drying process further after the above-mentioned further binder supply process as needed. In the further drying process, as well as the above, infrared dryers such as near infrared rays and far infrared rays, hot air dryers, electromagnetic wave dryers, gas dryers, drum dryers, hot roll dryers and the like are conventionally known. A dryer is preferably used. In particular, after the binder coating by gravure printing as described above is performed, the binder is sufficiently impregnated in the fiber sheet. Therefore, in this drying step, it is also preferable to efficiently perform the heat treatment at a higher temperature. From this point of view, drying with a near infrared ray, far infrared ray dryer or the like is preferable. Moreover, it is not limited to the case where it dries with one dryer, You may dry, installing several dryers and sending the raw material fiber sheet 2 to each dryer sequentially. Furthermore, a plurality of types of dryers may be used in combination in order to perform heat treatment according to the type and amount of the applied binder liquid and other purposes.

(Further compression / pressing process)
In the present embodiment, after the above-described drying step, a compression / pressing step may be further included as appropriate. Although there is no restriction | limiting in particular as a further compression and press part, For example, it is also preferable that a pair of vertical roll, a pair of horizontal roll, etc. are provided.

When the raw fiber sheet 2 that has undergone the above steps is provided as a wet wipe that is finally used in a wet state, an application step of applying a cleaning liquid thereto, a folding step, a cutting step, Etc. may be sent sequentially.
In the cleaning liquid application step, the cleaning liquid is applied and impregnated according to the application. As a result, a wet-type pulp pile fiber sheet in which the cleaning liquid is applied and impregnated is produced. It is also preferable to produce a dry-type pulp pile sheet without applying a cleaning liquid. In addition, before applying and impregnating the cleaning liquid, it is provided with a winding process that winds up the pulp pile fiber sheet and stored separately. May be provided.

  In the folding step, the fiber sheet is guided to a folding machine and folded at a predetermined number of times. After the folding step, the fiber sheet is cut to a predetermined size to obtain a laminated folded body (water absorbent article).

  When the pulp fiber sheet is provided as a wet type wipe or the like, as the cleaning liquid, water, a water-soluble organic solvent, a crosslinking agent made of a polyvalent metal salt for crosslinking a water-soluble binder, As an essential component, and optionally contains optional components such as a surfactant, a touch modifier, a bactericidal agent, a preservative, a deodorant, a bleaching agent, a chelating agent, and a fragrance.

  The water-soluble organic solvent is not particularly limited, and examples thereof include monohydric alcohols such as ethanol, methanol and isopropyl alcohol, and glycols such as ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, hexylene glycol and dipropylene glycol. Monoethers or diethers of these glycols with lower alcohols such as methanol, ethanol, propanol, butanol, esters of the glycols with lower fatty acids, polyhydric alcohols such as glycerin, sorbitol, polyethylene glycol, etc. it can. These water-soluble organic solvents may be used alone or in combination of two or more. The content of the water-soluble organic solvent in the cleaning liquid is preferably 10 to 40% by weight. Moreover, in another aspect, as said content, 17 to 28 weight% is preferable.

  The polyvalent metal salt (crosslinking agent) is not particularly limited, and for example, divalent metal salts such as calcium chloride, zinc sulfate, zinc nitrate, and zinc chloride can be used. It is selected as appropriate. These may be used alone or in combination of two or more. The content of the crosslinking agent in the cleaning liquid is preferably 2.0 to 4.5% by weight. Moreover, as content of the said crosslinking agent as another aspect, 2.5 to 4.3 weight% is preferable. In still another embodiment, the content of the crosslinking agent is preferably 3.0% by weight to 4.2% by weight.

  Examples of the surfactant include an anionic surfactant, a nonionic surfactant, a cationic surfactant, and an amphoteric surfactant. These surfactants may be used alone or in combination of two or more. Although it may be used in combination, it is particularly preferable to use one or more nonionic surfactants such as polyoxyalkylene alkyl ether, alkylglycoside, sorbitan fatty acid ester and the like. The content of optional components such as surfactants can be appropriately selected as necessary.

  The feel improver is not particularly limited as long as it can improve the skin feel when touched. For example, talc, boron nitride, polyethylene, (dimethicone / divinyldimethicone / silsesquioxane) crosspolymer, silica , And at least one powder selected from mica. These feel improvers may be used alone or in combination of two or more.

-Water-degradable pulp pile fiber sheet-
The water-decomposable pulp-laden fiber sheet of the present invention is at least 1.5 to 15% by weight in solid content of a binder (A) having a carboxyl group in a raw fiber sheet made of pulverized pulp or mainly pulverized pulp and in a non-wet state. The binder (B) having a group represented by the following formula (1) as a basic polymerization unit is contained in a solid content of 0.5 to 6.0% by weight, and, if necessary, other components.
Equation _{(1): - [CH 2} -CHX] -
However, in Formula (1), X represents at least one of a hydrogen element, a hydroxyl group, and an acetate group.

  In the hydrolysable pulp-laden fiber sheet of the present invention, the raw fiber sheet, the binder (A) having a carboxyl group, the binder (B) having a group represented by the above formula (1) as a basic polymerization unit, and the like are described above. Are preferably used. The content of the binder (A) having a carboxyl group with respect to the raw fiber sheet in a non-wet state is preferably 2.0 to 13% by weight in terms of solid content. In another embodiment, the solid content is preferably 2.5 to 12.5 weight. The content of the binder (B) having the group represented by the formula (1) as a basic polymerization unit with respect to the raw fiber sheet in a non-wet state is preferably 0.6 to 5.5% by weight in solid content. In another embodiment, the solid content is preferably 0.7 to 5.0 weight. If the content of the binder is within the above numerical range, a water-decomposable pulp-laden fiber sheet having excellent water decomposability, sufficient strength, and excellent flexibility can be obtained.

  Since the physical strength is further improved, the binder contained is preferably contained in the hydrolyzable pulp fiber sheet of the present invention in a crosslinked state. Moreover, when the water-decomposable pulp pile fiber sheet of this invention is used for a wet wipe use, it is as having mentioned above also about the cleaning liquid etc. which can be applied suitably.

  In the water-decomposable pulp-laden sheet of the present invention, it is also preferable to appropriately provide a surface sheet layer as described above. The material of the top sheet layer is preferably liquid-permeable, for example, it is preferable to use pulp paper or paper formed from a material mainly made of pulp. In this case, the pulp content is preferably 30% or more. Moreover, as another aspect, it is also preferable that it is 50% or more. Furthermore, as another aspect, what is 80% or more is preferable. If the blending amount of the pulp is such a ratio, a highly flexible pulp fiber sheet can be obtained.

The basis weight of the finished pulp pile fiber sheet is preferably 80 g / m ² or less, and more preferably 60 g / m ² or less. By making the basis weight of the pulp fiber sheet into the above-described range, it is possible to easily manufacture and package the product using the pulp fiber sheet. Thereby, it can comprise so that it may be easy to use and bulky that a user is easy to pack. Moreover, the fiber density does not become too large by setting the basis weight of the fiber sheet within the above range. As a result, the amount of binder liquid for joining fibers can be reduced.

(Ease of loosening of water-degradable pulp pile fiber sheet)
In such a hydrolysable pulp pile sheet, the ease of loosening measured in accordance with JISP4501 is within 300 seconds. Based on the evaluation of the ease of loosening in water, it is evaluated that the water-decomposable pulp pile fiber sheet has an appropriate strength and also has an excellent water-decomposability.
JISP4501 evaluates the ease of loosening of the test piece by measuring as follows. That is, a 114 mm square test piece is put into the water that is sold at 600 revolutions per minute, and the rotational speed temporarily drops to about 500 revolutions due to the resistance of the test piece. As the test piece is loosened, the number of revolutions increases, and the time for recovery from the test piece to 540 revolutions is measured.

The hydrolysable pulp pile fiber sheet is excellent in ease of loosening and recovers within 300 seconds. The water-decomposable pulp pile fiber sheet can be obtained efficiently without going through the paper making process, the shape is maintained well without being laminated with the paper made hydrolyzed paper, and it has an appropriate strength and an appropriate strength. It has flexibility and, furthermore, excellent water decomposability as described above. Preferably,
The recovery is preferably performed within 250 seconds, more preferably within 200 seconds.

(Another example of a method for producing a water-degradable pulp pile fiber sheet)
FIG. 2 is a process diagram for explaining a method for suitably producing a hydrolyzable pulp fiber sheet according to one embodiment (second example) of the present invention.
In this 2nd example, between the grinding | pulverization part 20 and the binder liquid supply part 40, the compression press by the compression and the press part 30 with respect to the raw material fiber sheet 2 is not given like the said 1st example. In FIG. 2, reference numeral 7 denotes a holding belt conveyor disposed on the conveyor belt 6 between the pulverizing unit 20 and the binder liquid supply unit 40. In this second example, a compression pressing process on the raw fiber sheet 2 is performed after the process in the drying unit 50 as necessary. In FIG. 2, reference numeral 43 denotes an airflow forming unit that is disposed under the conveying belt 6 in the binder liquid supply unit 40 and sucks air through the opening of the conveying belt, and reference numeral 53 denotes the conveying belt 6 in the drying unit 50. It is an air flow forming unit that sucks air through an opening of a conveyance belt disposed below.
Since the remaining points in the second example are substantially the same as those in the first example, the remaining points are denoted by the same reference numerals as those used in FIG. Is omitted.

  The pulp pile fiber sheet of the present invention having good water disintegration is not only water disintegrating paper but also absorbent articles such as diapers, sanitary napkins and incontinence pads, and absorbent articles such as disposable clothing, diapers, disposable sanitary napkins and incontinence pads. Can also be used.

  The embodiments and modifications described above can be used in appropriate combination, but detailed description thereof is omitted. Further, the present invention is not limited to the embodiment described above.

1: raw material sheet, 1a: pulverized raw material, 2: raw material fiber sheet, 5: binder liquid, 6: conveying belt, 10: raw material sheet supply unit, 20: pulverizing unit, 21: housing, 22: pulverizer, 23: airflow Forming unit, 30: compression / pressing unit, 31: flat roll, 40: binder liquid supply unit, 41: binder liquid spraying device, 50: first drying unit, 51: first dryer

Claims (13)

At least one side of the raw fiber sheet in a non-wet state made of pulverized pulp or mainly pulverized pulp,
1 to 10% by weight of one or more binders (A) having a carboxyl group selected from carboxymethylcellulose (CMC), carboxyethylcellulose, carboxymethylethylcellulose, carboxymethylated starch or a salt thereof ;
0.25 to 2.5% by weight of binder (B) having a group represented by the following formula (1) as a basic polymerization unit;
A binder supplying step for supplying a binder liquid prepared by blending,
After the binder supply step, a drying step of drying the raw fiber sheet,
A method for producing a hydrolyzable pulp fiber sheet, comprising:
Formula _{(1): - [CH 2} -CHX] -
However, in Formula (1), X represents at least one of a hydrogen element, a hydroxyl group, and an acetate group.   In the said binder supply process, the content ratio (weight ratio) ((A) / (B)) in a binder liquid is a manufacture of the water-degradable pulp fiber sheet of Claim 1 which is 1 / 1-8 / 1. Method.   The method for producing a hydrolyzable pulp fiber sheet according to claim 1 or 2, wherein in the binder supplying step, the binder liquid is applied to both surfaces of the raw fiber sheet.   The method for producing a hydrolyzable pulp fiber sheet according to any one of claims 1 to 3, wherein (A) and (B) are compatible with each other.   The hydrolysable pulp-laden fiber according to any one of claims 1 to 4, wherein (A) is carboxymethylcellulose, (B) is polyvinyl alcohol, and a blending temperature when producing the binder liquid is 50 ° C or higher. Sheet manufacturing method. At least one kind having a carboxyl group selected from carboxymethylcellulose (CMC), carboxyethylcellulose, carboxymethylethylcellulose, carboxymethylated starch or a salt thereof , on a raw fiber sheet made of pulverized pulp or mainly pulverized pulp and in a non-wet state 1.5 to 15% by weight of two or more binders (A) , and (B) 0.5 to 6.0% by weight of a binder having a group represented by the following formula (1) as a basic polymerization unit. A hydrolyzable pulp fiber sheet, which is formed by applying and drying.
Equation _{(1): - [CH 2} -CHX] -
However, in Formula (1), X represents at least one of a hydrogen element, a hydroxyl group, and an acetate group.   Furthermore, the water-decomposable pulp pile fiber sheet of Claim 6 which has a liquid-permeable surface sheet layer.   The hydrolyzable pulp fiber sheet according to claim 6 or 7, wherein (A) is carboxymethylcellulose.   The hydrolysable pulp pile fiber sheet according to any one of claims 6 to 8, wherein (B) is polyvinyl alcohol.   Furthermore, the water-degradable pulp pile fiber sheet according to any one of claims 6 to 9, which is impregnated with a cleaning liquid and is wet.   The hydrolyzable pulp fiber according to claim 10, wherein the cleaning liquid contains 10 to 40% by weight of a water-soluble organic solvent and 2.0% to 4.5% by weight of a divalent metal salt. Sheet.   The water-decomposable pulp pile fiber sheet according to claim 10 or 11, wherein the cleaning liquid contains a feel improver. The hydrolysis according to claim 12, wherein the feel improver is at least one of powders selected from talc, boron nitride, polyethylene, (dimethicone / divinyldimethicone / silsesquioxane) crosspolymer, silica, and mica. Synthetic fiber sheet.

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