JP7229802B2 - Cellulose-based knitted fabric and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a cellulose-based knitted fabric having high strength and flexibility and excellent durability to heavy washing, and a method for producing the same.

A cellulosic knitted fabric knitted using cellulosic fibers inevitably suffers from deterioration in strength and flexibility, shrinkage, and the like after heavy washing (industrial washing), and suppression of these problems has been a problem. In response to this, processing such as mercerization (caustic soda) for swelling cotton fibers and liquid ammonia processing has been performed (Patent Document 1). Resin processing methods for cross-linking cotton fibers have also been investigated, and for example, modification processing by chemical cross-linking using cotton fiber-reactive resins such as gluoxal-based resins has been disclosed (Patent Document 2).

However, although the method of Patent Literature 1 improves the strength to a certain extent, it cannot be said that the dimensional change after repeated washing is sufficiently suppressed, and the softness may be reduced and the texture may be impaired. Moreover, the method of Patent Document 2 also poses a problem of a decrease in strength and flexibility after washing, in addition to a decrease in strength itself. In particular, knitted fabrics such as non-silk, fine count, smooth, and jersey fabrics have large dimensional changes and tend to skew, so these are not effective processing methods. In addition, it may be difficult to apply these processing methods due to problems such as hardening of the texture, generation of free formalin, decrease in gloss and strength, especially for thin knitted fabrics while maintaining flexibility and strength. It was the actual situation that it was difficult to improve.

JP-A-5-230768 JP-A-8-284068

Therefore, there is a demand for a treatment method for cellulose-based knitted fabrics that can improve the strength without impairing the texture, and can reduce the degree of deterioration in strength and flexibility even after heavy washing, and can suppress dimensional changes. An object of the present invention is to provide such a processing method.

As a result of intensive research to solve the above problems, the present inventors have found that by treating a cellulose-based knitted fabric with a treatment liquid containing cellulose nanofibers, a resin, and a blocked isocyanate-based cross-linking agent, the texture is not impaired. In addition, the inventors have found that the strength is improved, the strength and flexibility are less reduced even after heavy washing, and the dimensional change is suppressed, leading to the completion of the present invention.

That is, the present invention includes a step of treating a knitted fabric containing cellulose fibers with a treatment liquid containing cellulose nanofibers (hereinafter sometimes referred to as "CNF"), a resin and a blocked isocyanate cross-linking agent (hereinafter referred to as " A method for producing a cellulose-based knitted fabric (hereinafter sometimes referred to as a "CNF-containing knitted fabric") including a CNF-containing treatment.

Further, the present invention comprises a knitted fabric containing cellulose fibers, contains cellulose nanofibers, a resin and a blocked isocyanate-based cross-linking agent, and contains cellulose nano The fiber content is 0.1 to 0.8 parts by mass, the cellulose nanofiber content is 2 to 50 parts by mass with respect to the total content of 100 parts by mass of the resin and the blocked isocyanate crosslinking agent, and the resin and the blocked isocyanate crosslink. The cellulose-based knitted fabric is characterized in that the agent content ratio is 1:2 to 6:1, and the cellulose nanofibers have an average fiber diameter of 3 to 100 nm and an aspect ratio of 100 to 9,000.

INDUSTRIAL APPLICABILITY The cellulose-based knitted fabric of the present invention has improved strength without hardening its texture, maintains its strength even after heavy washing, and suppresses decrease in flexibility and dimensional change.

1 is a field emission scanning electron microscope (FE-SEM) 2000 times enlarged photograph of the CNF-containing knitted fabric of Example 1 after industrial washing for 600 minutes. 1 is a field emission scanning electron microscope (FE-SEM) magnified 30,000-fold photograph of the CNF-containing knitted fabric of Example 1 after industrial washing for 600 minutes. 1 is a field emission scanning electron microscope (FE-SEM) magnified 2000-fold photograph of the knitted fabric (not containing CNF) of Comparative Example 4 after industrial washing for 600 minutes. 1 is a field emission scanning electron microscope (FE-SEM) magnified 30,000-fold photograph of the knitted fabric (not containing CNF) of Comparative Example 4 after industrial washing for 600 minutes.

The knitted fabric constituting the cellulosic knitted fabric of the present invention contains cellulosic fibers. Examples of the cellulosic fibers include vegetable fibers such as cotton and linen, regenerated cellulosic fibers such as rayon, lyocell and cupra, and semi-synthetic fibers such as diacetate and triacetate. Among these, cotton is preferably used from the viewpoint of being excellent in water absorption, strength and flexibility. The cellulosic fiber preferably has an English cotton count of 20 to 100, more preferably 30 to 80. Either a single yarn or two-ply yarn may be used. If the British cotton count is too large (the yarn is too thin), the strength of the knitted fabric after heavy washing and the effect of suppressing dimensional change may decrease. On the other hand, if the English cotton count is too small (the yarn is too thick), the knitted fabric will be thicker or the density of the knitted fabric will be higher, which may impair flexibility.

The knitted fabric may contain fibers other than the cellulosic fibers as long as the effects of the present invention are not impaired. Examples of fibers other than cellulosic fibers include synthetic fibers such as polyester fibers, nylon fibers, and acrylic fibers. From the viewpoint of maintaining water absorption and flexibility, the proportion of cellulosic fibers in the entire fibers constituting the knitted fabric is preferably 70% by mass (hereinafter simply indicated as "%") or more, more preferably 80%. % or more, particularly preferably 90% or more.

The knitted fabric is obtained by knitting according to a conventional method. Any knitting machine such as a flat knitting machine, a circular knitting machine, and a warp knitting machine can be used. As for the knitting structure, plain knitting, rib knitting, pearl knitting, interlocking, atlas knitting, Denby knitting, cord knitting, etc. can be appropriately selected and used without particular limitation. The basis weight of the knitted fabric is preferably 100-240 g/m ² , more preferably 120-220/m ² . If the basis weight of the knitted fabric is too small (too light), the strength of the knitted fabric and the effect of suppressing dimensional change after heavy washing may decrease. On the other hand, if the basis weight of the knitted fabric is too large (too heavy), the CNF-processed knitted fabric will become thicker or have a higher density, which may impair the texture.

By treating the knitted fabric with a treatment liquid containing cellulose nanofibers, a resin, and a blocked isocyanate-based cross-linking agent (CNF-containing treatment), a cellulose-based knitted fabric containing cellulose nanofibers, a resin, and a blocked isocyanate-based cross-linking agent is obtained. A fabric (CNF-containing knitted fabric) is obtained.

Cellulose nanofibers are fibers composed of cellulose microfibrils. The cellulose raw material may be plant, animal or any obtained from a cellulose biosynthetic system. When the raw material is a plant (hereinafter also referred to as "pulp"), it may be derived from broad-leaved trees or coniferous trees, and the CNF production method (fibrillation treatment) may be chemical treatment, mechanical treatment, or a combination of chemical treatment and mechanical treatment. However, CNF made from pulp obtained by chemical treatment is preferable because it has a low hydrophobic lignin content and high water retention. It is more preferable to use hardwood-derived pulp, which has a lower lignin content than softwood-derived pulp, and which is chemically defibrated. In addition, although the reason is not clear, hardwood-derived pulp that has been defibrated by chemical treatment is preferable to softwood-derived pulp because the strength of the fiber tends to be superior after the inclusion treatment in the fiber. The average fiber diameter of CNF is preferably 3 to 100 nm, more preferably 20 to 100 nm. If the average fiber diameter of the CNF is too small, the strength of the fiber itself may decrease, and the reinforcing effect of improving the strength of the knitted fabric and suppressing dimensional change may decrease. On the other hand, if the average fiber diameter of the CNF is too large, the fineness is insufficient and the dispersibility of the fibers is insufficient, and there is a risk that the reinforcing effect of improving the strength of the knitted fabric and suppressing dimensional change will be reduced. Also, the aspect ratio is preferably in the range of 100 to 9,000, more preferably 100 to 5,000, still more preferably 100 to 3,000. If the aspect ratio of CNF is too small, the strength of the fiber itself may be reduced, and the reinforcing effect of improving the strength of the knitted fabric and suppressing dimensional change may be reduced. On the other hand, if the aspect ratio is too large, the fibers will not be sufficiently finely divided, and the dispersibility of the fibers will be insufficient. The average fiber diameter and aspect ratio of CNF herein mean values measured by the method described in Examples.

Examples of resins include acrylic resins, polyester resins, polyurethane resins, and the like, but acrylic resins and polyester resins are preferable from the viewpoint of making it difficult to impair the water absorption and flexibility of the knitted fabric, and particularly A polyester-based resin is preferred. Examples of the acrylic resin include acrylic emulsion (trade name “Senka EMX-03” manufactured by Senka Co., Ltd.). Polyester-based resins include, for example, polyester-based polymer resins (trade name “DCOM C256” manufactured by Takamatsu Yushi Co., Ltd.).

The blocked isocyanate-based cross-linking agent may be aliphatic, alicyclic or aromatic. For example, as an aliphatic blocked isocyanate-based cross-linking agent, manufactured by Nicca Chemical Co., Ltd., trade name "NK Assist NY", as an aromatic blocked isocyanate-based cross-linking agent, manufactured by Nicca Chemical Co., Ltd., trade name "NK Assist V" are mentioned. Aliphatic blocked isocyanate-based cross-linking agents are more preferable from the viewpoint of making it difficult to damage the texture of the knitted fabric.

The treatment liquid containing the CNF, resin, and blocked isocyanate-based cross-linking agent may be a solvent-based treatment liquid, but is preferably an aqueous treatment liquid such as an aqueous solution or an aqueous dispersion. The treatment method with the treatment liquid is not particularly limited, and various methods such as pad dry method, pad steam method, pad dry steam method, gravure coating method, spray method, etc. It can be done by For example, in the pad dry method or the like, the drawing rate after immersion in the treatment liquid is preferably 80 to 100%, more preferably 90 to 100%. When the treatment liquid is applied by a gravure coating method or the like, a known thickener can be added to adjust the viscosity of the treatment liquid.

After the treatment with the above treatment solution, drying and heat treatment is performed using a drying machine or the like. As for the dry heat treatment conditions, it is preferable to perform dry drying at a drying temperature of 100 to 120° C. for 2 to 5 minutes, followed by heat treatment at a curing temperature of 140 to 160° C. for 1 to 3 minutes.

The content of CNF contained in the cellulose-based knitted fabric of the present invention (in terms of solid content) is 0.1 to 0.8 parts per 100 parts by mass of the knitted fabric (hereinafter simply referred to as "parts"). is preferred, and a range of 0.2 to 0.7 parts is more preferred. If the amount of CNF is too low, the concentration becomes too dilute and may not be contained uniformly when incorporated into the knitted fabric, and there is a risk that stable strength improvement of the knitted fabric and suppression of dimensional change may not be obtained. On the other hand, if there is too much CNF, the problem of an increase in solution viscosity may occur, making it difficult to incorporate. The resin content (in terms of solid content) is preferably 0.8 to 5 parts, more preferably 0.8 to 4 parts, per 100 parts of the knitted fabric. The content of the blocked isocyanate-based cross-linking agent (in terms of solid content) is preferably 0.7 to 3 parts, more preferably 1 to 2 parts, per 100 parts of the knitted fabric.

The CNF content is preferably 2 to 50 parts, more preferably 5 to 30 parts, per 100 parts of the total content of the resin and blocked isocyanate-based cross-linking agent. If the amount of CNF is too low, the concentration becomes too thin and may not be contained uniformly when incorporated into the knitted fabric. On the other hand, if CNF is too much, a problem of increased solution viscosity may occur, making it difficult to incorporate CNF into the knitted fabric. On the other hand, the weight ratio of the resin to the blocked isocyanate-based cross-linking agent is preferably 1:2 to 6:1, more preferably 1:1 to 4:1. If the content ratio of the blocked isocyanate-based cross-linking agent is too low, the CNF and resin contained in the knitted fabric may fall off after strong washing, and the strength of the knitted fabric and suppression of dimensional change may decrease. On the other hand, if the content of the blocked isocyanate-based cross-linking agent is too high, the flexibility of the knitted fabric may be impaired.

<Manufacturing method>
The method for producing a cellulose-based knitted fabric of the present invention includes a step of scouring and bleaching a cellulose-based knitted fabric, and a step of treating the scouring-bleached cellulose-based knitted fabric with the above-mentioned CNF, a resin, and a blocked isocyanate-based cross-linking agent. and a step of treating with a treatment liquid that

<Scouring and bleaching process>
In the scouring/bleaching step, the cellulosic knitted fabric before scouring/bleaching is scoured and bleached. By scouring and bleaching, the impurities in the knitted fabric are removed and the pigment is bleached. The scouring step and the bleaching step may be performed separately or simultaneously in one bath. For scouring/bleaching treatment, for example, using a jet dyeing machine, 90% of the cellulose-based knitted fabric before scouring/bleaching treatment is placed in an aqueous solution containing sodium hydroxide used for scouring treatment and hydrogen peroxide used for bleaching treatment. It can be carried out by immersion and heat treatment at ~95°C for 30 to 60 minutes. The concentration of sodium hydroxide in the aqueous solution used for scouring/bleaching is preferably 0.2 to 2 g/L, more preferably 0.5 to 1.5 g/L. Further, the concentration of hydrogen peroxide in the aqueous solution is preferably 0.5 to 7 g/L, more preferably 0.7 to 5 g/L, and further preferably 0.7 to 3 g/L. more preferred. In addition, the aqueous solution may contain stabilizers, penetrants, sequestering agents, and the like. Stabilizers include silicates such as sodium silicate. Examples of stabilizers that can be used include Hyper N (trade name) manufactured by Daito Pharmaceutical Co., Ltd., Neolate PH-55F (trade name) manufactured by Nicca Chemical Co., Ltd., and the like. The stabilizer concentration in the aqueous solution is preferably 1-4 g/L. Penetrants include nonionic surfactants such as polyoxyethylene alkyl ethers. As the penetrant, for example, Scoreroll TS1169 (trade name) manufactured by Kitahiro Chemical Co., Ltd., Daisurf TW20 (trade name) manufactured by Daiichi Kogyo Seiyaku Co., Ltd., and the like can be used. The penetrant concentration in the aqueous solution is preferably 0.2 to 4 g/L. Sequestering agents include polyphosphates such as sodium tripolyphosphate, aminoacetates such as ethylenediaminetetraacetate, nitrilotriacetate, diethylenetriaminepentaacetate, oxalates, citrates, gluconates, and oxycarboxylic acids. salts, aminotrimethylene phosphonates, ethylenediaminetetramethylene phosphonates, diethylenetriaminepentamethylene phosphonates, acrylic acid-based polymers, maleic acid-based polymers, and the like. As the sequestering agent, for example, Cereche 200 (trade name) manufactured by Kao Corporation, Neo Crystal 80 (trade name) manufactured by Nicca Chemical Co., Ltd., and the like can be used. The concentration of the sequestering agent in the aqueous solution is preferably 0.1-1 g/L. After the scouring/bleaching treatment, a neutralization treatment step of neutralizing with an inorganic acid such as sulfuric acid or hydrochloric acid, or an organic acid such as acetic acid or formic acid, and/or a water washing step may be provided.

<Processing process>
The scouring/bleaching cellulose-based knitted fabric in the scouring/bleaching step is treated with a treatment liquid containing CNF, a resin, and a blocked isocyanate-based cross-linking agent. The treatment liquid containing the CNF, resin, and blocked isocyanate-based cross-linking agent is preferably an aqueous treatment liquid such as an aqueous solution or an aqueous dispersion. The CNF content (in terms of solid content) in the treatment liquid is preferably 1 to 8 g/L, more preferably 2 to 7 g/L. The content of the resin in the treatment liquid (in terms of solid content) is preferably 2 to 70 g/L, more preferably 5 to 60 g/L. The content of the blocked isocyanate-based cross-linking agent in the treatment liquid (in terms of solid content) is preferably 2 to 40 g/L, more preferably 5 to 30 g/L. As a treatment method with a treatment liquid, various methods such as a pad dry method, a pad steam method, a pad dry steam method, a coating method, and a spray method can be used. For example, in the pad dry method, the cellulose-based knitted fabric after scouring and bleaching is immersed in the above-described treatment solution using a drying machine or the like in an expanded state for several seconds, and then squeezed with a mangle. 80 to 100% is preferred, and 90 to 100% is more preferred. Then, after dry drying at a drying temperature of 100 to 120° C. for 2 to 5 minutes, heat treatment is preferably performed at a curing temperature of 140 to 160° C. for 1 to 3 minutes.

In addition to the above steps, the production method of the present invention may include a dyeing step, a finishing step, and the like, if necessary.

EXAMPLES The present invention will be described in more detail below with reference to examples, etc., but the present invention is not limited to these examples.

[Reference example 1]
<Scouring and bleaching (knitted fabric A1)>
One roll (width 1m, length 50m) of 100% cotton count 40/1 milling machine (basis weight 185g/m ² , 37 inches, 18.5 gauge) was put into a 10kg jet dyeing machine.
For scouring and bleaching, after supplying 150 L of industrial water to the machine, add 4 g/L of 35% aqueous hydrogen peroxide solution (concentration of hydrogen peroxide in industrial water: 1.4 g/L) and 48% sodium hydroxide into the industrial water. Aqueous solution 2 g/L (concentration of sodium hydroxide in industrial water 0.96 g/L), hydrogen peroxide stabilizer (trade name: Hyper N (manufactured by Daito Pharmaceutical Co., Ltd.)) 2 g/L, nonionic penetrant (trade name: Score Roll TS1169 (manufactured by Kitahiro Chemical Co., Ltd.)) 2 g/L, sequestering agent (trade name: Ceresh 200 (manufactured by Kao Corporation)) 0.5 g/L Added to industrial water. The knitted fabric is immersed in industrial water so that the ratio of the mass (kg) of the knitted fabric to the volume (L) of the prepared industrial water is 1:15, the liquid temperature is raised to 95 ° C., and the scouring and bleaching treatment is performed for 30 minutes. bottom. Subsequently, the knitted fabric was placed in 150 L of a neutralizing solution containing 0.5 g/L of a 76% formic acid aqueous solution, treated at room temperature for 20 minutes, washed twice, dehydrated and dried.

[Reference example 2]
<Scouring and bleaching (knitted fabric A2)>
One roll of 100% cotton cotton count 60/2 kanoko (metsuke 200 g/m ² , 30 inches, 28 gauge) gray fabric (width 1 m, length 50 m), 10 kg was put into a liquid jet dyeing machine, and knitted fabric A1. manufactured in the same manner as

[Example 1]
160 g/L of cellulose nanofiber aqueous dispersion B1 (trade name: ELLEX-S (manufactured by Daio Paper Co., Ltd.) (solid content: 2%)) obtained by chemically fibrillating hardwood-derived pulp with an average fiber diameter of 20 to 30 nm. , Resin C1 (trade name: DCOM C256 (manufactured by Takamatsu Yushi Co., Ltd.) (solid content: 14%)) made of polyester polymer resin at 60 g / L, and a cross-linking agent D1 made of aliphatic block isocyanate (trade name: NK Assist NY (manufactured by Nicca Chemical Co., Ltd.) (solid content: 39%)) was added to industrial water so as to be 40 g/L and mixed to prepare a treatment liquid. The knitted fabric A1 prepared in Reference Example 1 was dipped in this treatment solution using a drying machine for several seconds in an expanded state, then the knitted fabric was squeezed with a mangle (squeezing rate 100%), and dried at 120 ° C. for 5 minutes. , a heat drying treatment was performed at a curing temperature of 150°C for 2 minutes to obtain a cellulose-based knitted fabric. It was observed with an electron microscope (FE-SEM). The images are shown in FIGS. Table 1 shows the contents (parts) of CNF, resin, and cross-linking agent per 100 parts of the knitted fabric before the CNF-containing treatment in the obtained cellulose-based knitted fabric (CNF-containing knitted fabric). The same applies to the following examples and comparative examples.

[Example 2]
A cellulose-based knitted fabric was produced in the same manner as in Example 1, except that the amount of resin C1 added was 80 g/L. That is, 160 g/L of cellulose nanofiber aqueous dispersion B1, 80 g/L of resin C1, and 40 g/L of crosslinking agent D1 were added to industrial water and mixed to prepare a treatment liquid. The knitted fabric A1 prepared in Reference Example 1 was dipped in this treatment solution using a drying machine for several seconds in an expanded state, then the knitted fabric was squeezed with a mangle (squeezing rate 100%), and dried at 120 ° C. for 5 minutes. , a heat drying treatment was performed at a curing temperature of 150°C for 2 minutes to obtain a cellulose-based knitted fabric.

[Example 3]
A cellulose-based knitted fabric was produced in the same manner as in Example 1, except that the amount of the cross-linking agent D1 added was 60 g/L. Specifically, 160 g/L of cellulose nanofiber aqueous dispersion B1, 60 g/L of resin C1, and 60 g/L of crosslinking agent D1 were added to industrial water and mixed to prepare a treatment liquid. The knitted fabric A1 prepared in Reference Example 1 was dipped in this treatment solution using a drying machine for several seconds in an expanded state, then the knitted fabric was squeezed with a mangle (squeezing rate 100%), and dried at 120 ° C. for 5 minutes. , a heat drying treatment was performed at a curing temperature of 150°C for 2 minutes to obtain a cellulose-based knitted fabric.

[Example 4]
A cellulosic knitted fabric was produced in the same manner as in Example 3, except that resin C2 was used instead of resin C1. That is, 160 g / L of cellulose nanofiber aqueous dispersion B1, 60 g / L of resin C2 made of acrylic resin (trade name: Senka EMX-03 (manufactured by Senka Co., Ltd.) (solid content: 55 to 65%)), cross-linked Agent D1 was added to and mixed with industrial water so as to be 60 g/L to prepare a treatment liquid. The knitted fabric A1 prepared in Reference Example 1 was dipped in this treatment solution using a drying machine for several seconds in an expanded state, then the knitted fabric was squeezed with a mangle (squeezing rate 100%), and dried at 120 ° C. for 5 minutes. , a heat drying treatment was performed at a curing temperature of 150°C for 2 minutes to obtain a cellulose-based knitted fabric.

[Example 5]
Cellulose-based knitting was performed in the same manner as in Example 4 except that the amount of cellulose nanofiber aqueous dispersion B1 added was 60 g/L, the amount of resin C2 added was 80 g/L, and the amount of cross-linking agent D1 added was 20 g/L. I made land. Specifically, 60 g/L of cellulose nanofiber aqueous dispersion B1, 80 g/L of resin C2, and 20 g/L of crosslinking agent D1 were added to industrial water and mixed to prepare a treatment liquid. The knitted fabric A1 prepared in Reference Example 1 was dipped in this treatment solution using a drying machine for several seconds in an expanded state, then the knitted fabric was squeezed with a mangle (squeezing rate 100%), and dried at 120 ° C. for 5 minutes. , a heat drying treatment was performed at a curing temperature of 150°C for 2 minutes to obtain a cellulose-based knitted fabric.

[Example 6]
The procedure was the same as in Example 1, except that the amount of cellulose nanofiber aqueous dispersion B1 added was 320 g/L. Specifically, 320 g/L of cellulose nanofiber aqueous dispersion B1, 60 g/L of resin C1, and 40 g/L of crosslinking agent D1 were added to industrial water and mixed to prepare a treatment liquid. Knitted fabric A1 prepared in Reference Example 1 was immersed in this treatment liquid for several seconds in a spread state using a drying machine. Heat drying treatment was performed at a curing temperature of 150° C. for 2 minutes to obtain a cellulose-based knitted fabric.

[Example 7]
A cellulose-based knitted fabric was produced in the same manner as in Example 4, except that the amount of cellulose nanofiber aqueous dispersion B1 added was 320 g/L. Specifically, 320 g/L of cellulose nanofiber aqueous dispersion B1, 60 g/L of resin C2, and 60 g/L of crosslinking agent D1 were added to industrial water and mixed to prepare a treatment liquid. The knitted fabric A1 prepared in Reference Example 1 was dipped in this treatment solution using a drying machine for several seconds in an expanded state, then the knitted fabric was squeezed with a mangle (squeezing rate 100%), and dried at 120 ° C. for 5 minutes. , a heat drying treatment was performed at a curing temperature of 150°C for 2 minutes to obtain a cellulose-based knitted fabric.

[Example 8]
A cellulose-based knitted fabric was produced in the same manner as in Example 1, except that the aqueous cellulose nanofiber dispersion B2 was used instead of the aqueous cellulose nanofiber dispersion B1. That is, 160 g of cellulose nanofiber aqueous dispersion B2 (trade name: ELLEX-S (manufactured by Daio Paper Co., Ltd.) (solid content: 2%)) obtained by chemically defibrating softwood-derived pulp with an average fiber diameter of 20 to 30 nm. /L, 60 g/L of Resin C1, and 40 g/L of Crosslinking Agent D1 were added to and mixed with industrial water to prepare a treatment liquid. The knitted fabric A1 prepared in Reference Example 1 was dipped in this treatment solution using a drying machine for several seconds in an expanded state, then the knitted fabric was squeezed with a mangle (squeezing rate 100%), and dried at 120 ° C. for 5 minutes. , a heat drying treatment was performed at a curing temperature of 150°C for 2 minutes to obtain a cellulose-based knitted fabric.

[Example 9]
A cellulosic knitted fabric was produced in the same manner as in Example 1, except that A2 was used instead of the knitted fabric A1. Specifically, 160 g/L of cellulose nanofiber aqueous dispersion B1, 60 g/L of resin C1, and 40 g/L of crosslinking agent D1 were added to industrial water and mixed to prepare a treatment liquid. The knitted fabric A2 prepared in Reference Example 2 was dipped in this treatment solution using a drying machine for several seconds in a spread state, then the knitted fabric was squeezed with a mangle (squeezing rate 100%), and dried at 120 ° C. for 5 minutes. , a heat drying treatment was performed at a curing temperature of 150°C for 2 minutes to obtain a cellulose-based knitted fabric.

[Comparative Example 1]
Knitted fabric A1 that had undergone scouring and bleaching was used as it was without processing.

[Comparative Example 2]
The knitted fabric A1 was treated with a glyoxal-based resin. That is, 60 g / L of glyoxal resin E1 (trade name: Riken Resin FJ-1 (manufactured by Miki Riken Kogyo Co., Ltd.)), complex metal salt-based auxiliary agent E2 (trade name: Riken Fixer MX-18 (Miki Riken Kogyo Co., Ltd.) )) was added to industrial water so as to be 24 g/L and mixed to prepare a resin processing liquid. The knitted fabric A1 prepared in Reference Example 1 was dipped in this treatment solution using a drying machine for several seconds in an expanded state, then the knitted fabric was squeezed with a mangle (squeezing rate 100%), and dried at 120 ° C. for 5 minutes. , a heat drying treatment was performed at a curing temperature of 150°C for 2 minutes to obtain a cellulose-based knitted fabric.

[Comparative Example 3]
The knitted fabric A1 was mercerized using a mercerizing machine. That is, the knitted fabric A1 was immersed in a 20% sodium hydroxide aqueous solution of 26 Baume at 20 ° C., squeezed with a mangle, stretched in the warp direction for 1 minute, washed with hot water, and neutralized with 5 g / L of a 76% formic acid aqueous solution. It was neutralized by passing it through a liquid, and then washed with hot water, washed with water, and dried.

[Comparative Example 4]
A cellulosic knitted fabric was produced in the same manner as in Example 1, except that the cross-linking agent D1 was not used. Specifically, 160 g/L of cellulose nanofiber aqueous dispersion B1 and 60 g/L of resin C1 were added to industrial water and mixed to prepare a CNF/resin dispersion. The knitted fabric A1 prepared in Reference Example 1 was dipped in this treatment solution using a drying machine for several seconds in an expanded state, then the knitted fabric was squeezed with a mangle (squeezing rate 100%), and dried at 120 ° C. for 5 minutes. , a heat drying treatment was performed at a curing temperature of 150°C for 2 minutes to obtain a cellulose-based knitted fabric. The resulting knitted fabric was washed in the industrial laundering described below for 600 minutes and then field emission scanned using magnifications of 2000x and 30000x and field emission scanning electron microscopy (FE) using magnifications of 2000x and 30000x. -SEM). The images are shown in FIGS.

[Comparative Example 5]
A cellulosic knitted fabric was produced in the same manner as in Example 4, except that the cross-linking agent D1 was not used. Specifically, 160 g/L of cellulose nanofiber aqueous dispersion B1 and 60 g/L of resin C2 were added to industrial water and mixed to prepare a CNF/resin dispersion. The knitted fabric A1 prepared in Reference Example 1 was dipped in this treatment solution using a drying machine for several seconds in an expanded state, then the knitted fabric was squeezed with a mangle (squeezing rate 100%), and dried at 120 ° C. for 5 minutes. , a heat drying treatment was performed at a curing temperature of 150°C for 2 minutes to obtain a cellulose-based knitted fabric.

[Comparative Example 6]
A cellulose-based knitted fabric was produced in the same manner as in Example 1, except that the amount of cellulose nanofiber aqueous dispersion B1 added was 40 g/L. Specifically, 40 g/L of cellulose nanofiber aqueous dispersion B1, 60 g/L of resin C1, and 40 g/L of crosslinking agent D1 were added to industrial water and mixed to prepare a treatment liquid. The knitted fabric A1 prepared in Reference Example 1 was dipped in this treatment solution using a drying machine for several seconds in an expanded state, then the knitted fabric was squeezed with a mangle (squeezing rate 100%), and dried at 120 ° C. for 5 minutes. , a heat drying treatment was performed at a curing temperature of 150°C for 2 minutes to obtain a cellulose-based knitted fabric.

[Comparative Example 7]
A cellulose-based knitted fabric was produced in the same manner as in Example 4, except that the amount of cellulose nanofiber aqueous dispersion B1 added was 40 g/L. Specifically, 40 g/L of cellulose nanofiber aqueous dispersion B1, 60 g/L of resin C2, and 60 g/L of crosslinking agent D1 were added to industrial water and mixed to prepare a treatment liquid. The knitted fabric A1 prepared in Reference Example 1 was dipped in this treatment solution using a drying machine for several seconds in an expanded state, then the knitted fabric was squeezed with a mangle (squeezing rate 100%), and dried at 120 ° C. for 5 minutes. , a heat drying treatment was performed at a curing temperature of 150°C for 2 minutes to obtain a cellulose-based knitted fabric.

[Comparative Example 8]
A cellulose-based knitted fabric was produced in the same manner as in Example 1, except that the amount of cellulose nanofiber aqueous dispersion B1 added was 500 g/L. Specifically, 500 g/L of cellulose nanofiber aqueous dispersion B1, 60 g/L of resin C1, and 40 g/L of crosslinking agent D1 were added to industrial water and mixed to prepare a treatment liquid. The knitted fabric A1 prepared in Reference Example 1 was dipped in this treatment solution using a drying machine for several seconds in an expanded state, then the knitted fabric was squeezed with a mangle (squeezing rate 100%), and dried at 120 ° C. for 5 minutes. , a heat drying treatment was performed at a curing temperature of 150°C for 2 minutes to obtain a cellulose-based knitted fabric.

[Comparative Example 9]
A cellulose-based knitted fabric was produced in the same manner as in Example 4, except that the amount of cellulose nanofiber aqueous dispersion B1 added was 500 g/L. Specifically, 500 g/L of cellulose nanofiber aqueous dispersion B1, 60 g/L of resin C2, and 40 g/L of crosslinking agent D1 were added to industrial water and mixed to prepare a treatment liquid. The knitted fabric A1 prepared in Reference Example 1 was dipped in this treatment solution using a drying machine for several seconds in an expanded state, then the knitted fabric was squeezed with a mangle (squeezing rate 100%), and dried at 120 ° C. for 5 minutes. , a heat drying treatment was performed at a curing temperature of 150°C for 2 minutes to obtain a cellulose-based knitted fabric.

(average fiber diameter)
The cellulose-based knitted fabric of Example 1 obtained using the cellulose nanofiber aqueous dispersion B1 was observed with a field emission scanning electron microscope (FE-SEM) image at a magnification of 30000 times. Specifically, the width of a total of 50 fibers was randomly measured visually, and the average diameter of the measured values was defined as the average fiber diameter.

(average fiber length)
The length of each fiber was visually measured in the same manner as the average fiber diameter, and the median length of the measured value was taken as the average fiber length.

(aspect ratio)
It was calculated by dividing the average fiber length by the average fiber diameter.

As a result of the above measurements, the cellulose-based knitting of Example 1 obtained using the cellulose nanofiber aqueous dispersion B1 had an average fiber diameter of 30 nm and an aspect ratio of 150.

<Washing process>
(soap)
"JAFET standard combination detergent" (containing polyoxyethylene alkyl ether and sodium alpha olefin sulfonate) was used.

(Washing conditions)
Washing was carried out under the following conditions according to the high temperature accelerated washing method (washing method for products specified for 50 washings) described in the "Washing method for SEK mark textile products" established by the Textile Evaluation Technology Council. .
(1) Using a washer washing machine, 120 mL of "JAFET standard combination detergent" was added to 90 L of water to prepare a washing liquid.
(2) A knitted fabric (to-be-washed) and a load cloth were put into this washing liquid so that the bath ratio was 1:30, and the operation was started. A load cloth was added to keep the liquor ratio constant, and the total weight of the knitted fabric (laundry) and the load cloth was 3 kg.
(i) Wash at 80°C for 120 minutes
(ii) Drainage (3) Rinse using a domestic washing machine.
(iii) Knitted fabric (to be washed) + dehydration of load cloth (3 to 5 minutes)
(iv) 15 minute overflow rinse
(v) drainage
(vi) Dehydration (4) Steps (iv) to (vi) were repeated four times in total.
(5) Steps (i) to (vi) were repeated 5 times using a washer washing machine and a household washing machine.

(Drying method)
After washing, tumble drying or hanging drying was performed according to the drying method (8.39.6) of JIS L 1096:2010.
(1) Tumble drying was performed by the G method (method for a pulsator type electric washing machine for household use) and high-temperature tumble drying.
(2) Hanging drying was performed by line drying (hanging drying).

<Test method (evaluation method)>
The dimensional change rate, bursting strength and flexibility of the knitted fabrics obtained in Examples 1 to 9 and Comparative Examples 1 to 9 were measured and evaluated by the following methods.

(1) Dimensional change rate The dimensional change rate of the dried knitted fabric was measured according to QTEC (Japan Textile Product Quality and Technology Center) quality standards. A dimensional change rate of -8% to 0% in the case of tumble drying, and -6% to +5% in the case of hanging drying was accepted. [-] indicates contraction and [+] indicates elongation. The results are shown in Tables 1 and 2.

(2) Bursting strength The bursting strength of the knitted fabric before washing (unwashed) and after drying was measured according to JISL1018 (Mullen method). Five test pieces (15 cm × 15 cm) are sandwiched between the clamps (fasteners) of the "Mullen burst tester", and the strength when the rubber film expands and breaks through the test piece when pressure is applied, and the clamps (fasteners) ) was removed and the strength of the rubber film was measured and expressed as the difference between the two strengths. According to QTEC quality standards, dry burst strength of 400 kPa or more was considered acceptable. Results are shown in Tables 1 and 2.

(3) Judgment of flexibility (sensory test)
The knitted fabric tumble-dried after washing was evaluated for softness by a sensory test. The flexibility when the knitted fabric was touched was evaluated on a 5-point scale, and 2 or more was considered acceptable. Judgment was performed by one person skilled in the evaluation of texture of textile products. Results are shown in Tables 1 and 2.
5: Good 4: Slightly good 3: Acceptable 2: Slightly poor 1: Poor

As shown in Table 2, the resin treatment significantly reduced the strength, and the mercerization treatment did not satisfy the acceptance criteria for suppressing dimensional change after heavy washing, and a decrease in flexibility was also observed (Comparative Examples 1 to 3). Even in Comparative Examples 4 and 5, which were treated only with CNF and resin and did not use a cross-linking agent, the dimensional change after strong washing increased and the strength also decreased. On the other hand, the knitted fabric of each example using a blocked isocyanate-based cross-linking agent together with CNF and resin has improved strength, and the strength improvement after washing and the decrease in flexibility are small, and dimensional change is suppressed. . On the other hand, when the amount of CNF was small, strength reduction and shrinkage were observed (Comparative Examples 6 and 7), and when the amount of CNF was large, flexibility decreased (Comparative Examples 8 and 9). The hardwood-derived pulp was superior in strength to the softwood-derived pulp (Examples 1 and 9).

INDUSTRIAL APPLICABILITY According to the present invention, a cellulose-based knitted fabric having high strength and flexibility and excellent resistance to washing can be provided, and thus can be used as a method for processing knitted fabrics.

Claims (8)

Made of a knitted fabric containing cellulose fibers, containing cellulose nanofibers, a resin and a blocked isocyanate cross-linking agent, the content of cellulose nanofibers per 100 parts by mass of the knitted fabric is 0.1 to 0.8 parts by mass, and the resin The content of cellulose nanofibers is 2 to 50 parts by mass with respect to the total content of 100 parts by mass of the resin and the blocked isocyanate cross-linking agent, and the content ratio by mass of the resin and the blocked isocyanate-based cross-linking agent is 1:2 to 6:1, A cellulose-based knitted fabric, characterized in that the cellulose nanofibers have an average fiber diameter of 3 to 100 nm and an aspect ratio of 100 to 9,000. 2. The cellulose-based knitted fabric according to claim 1, wherein the cellulose nanofibers are obtained by defibrating pulp by chemical treatment. The cellulosic knitted fabric according to claim 1 or 2, wherein the resin is an acrylic resin and/or a polyester resin. The cellulose-based knitted fabric according to any one of claims 1 to 3, wherein the blocked isocyanate-based cross-linking agent is an aliphatic blocked isocyanate and/or an aromatic blocked isocyanate. The cellulosic knitted fabric according to any one of claims 1 to 4, wherein the cellulosic fiber is of British cotton count 20 to 100. The cellulosic knitted fabric according to any one of claims 1 to 5, wherein the knitted fabric has a basis weight of 100 to 240 g/m2. A method for producing a cellulose-based knitted fabric , comprising a step of treating a knitted fabric containing cellulose-based fibers with a treatment liquid containing cellulose nanofibers, a resin, and a blocked isocyanate-based cross-linking agent, wherein the resin in the treatment liquid and the block A method for producing a cellulose-based knitted fabric in which the content of cellulose nanofibers is 2 to 50 parts by mass with respect to the total content of 100 parts by mass of a doisocyanate-based cross-linking agent. 8. The method for producing a cellulose-based knitted fabric according to claim 7, wherein the content ratio of the resin to the blocked isocyanate-based cross-linking agent in the treatment liquid is 1:2 to 6:1.

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