JPS62264B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a sheet that has high physical properties and is extremely flexible.

In recent years, so-called artificial leather, which is a sheet material coated with viscoelastic resin, has greatly expanded its field of application.

The field of application is not limited to simply covering sheets for shoes, bags, chairs, etc., but has also expanded to the field of clothing, etc. However, there is no end to the ever-increasing sophistication of requirements for these artificial leather fields. The most typical requirement is, first of all, to make artificial leather more flexible. Furthermore, it has high physical properties such as being flexible and having high abrasion resistance and tear resistance.

Another major requirement was that the surface quality be beautiful.

Many approaches have been taken to meet such demands. The following are representative examples. That is, after using special fibers and applying a rubber-like viscoelastic resin, as typified by Japanese Patent Publication No. 42-27278, a portion of the special fibers are removed. Also, special public service in 1977.
A soluble binder typified by No. 18745 is applied to the fabric once, a viscoelastic resin is then applied, and the previously applied soluble binder is removed.
Furthermore, a method has been proposed in which a viscoelastic resin is applied after thinning the attenuable fibers, as typified by Japanese Patent Publication No. 46-41235 and Japanese Patent Application Laid-Open No. 51-75178.

Furthermore, various lubricants and the like are added to binders, products, etc. in order to soften them.

Although these had considerable merits, in the case of mixed spun fibers such as those typified by Japanese Patent Publication No. 42-27278, the fibers after one component has been extracted become so-called lotus root-like or fibrillar-like. This is often the case. In the former case, there is not much effect on softening the texture. On the other hand, in the case of fibrillation, it is true that the texture becomes softer, but it is difficult to achieve high physical properties. Furthermore, the solvent for the viscoelastic resin is often the solvent for the fiber constituents. For this reason, the application of the binder becomes extremely unstable, and it is difficult to continuously and stably produce a uniform product. Even if it were possible, it would be expensive. Next, in the case of Special Publication No. 45-18745, etc., the soluble binder is
It creates a boundary between the fibers and the viscoelastic resin, and in that sense it softens the texture, but it weakens the adhesion between the fibers and the viscoelastic material so much that it is difficult to achieve high physical properties. . Furthermore, when trying to use a nap type, there was a major drawback in that the nap nap easily came off. On the other hand, in the cases typified by JP-B-46-41235 and JP-A-51-75178, the bond between the fibers and the binder is strong, so even as a napped type, the napped type has great advantages such as difficulty in slipping out. However, the texture was a little rubber-like, and it was not satisfactory enough to obtain a sheet that was flexible and had high physical properties.

Furthermore, when a lubricant is added or provided to a binder or product, although it has certain effects, there are disadvantages such as it easily comes off during cleaning, and it bleeds out, making it unpleasant to feel.

In view of this situation, the inventors of the present invention have arrived at the present invention as a result of intensive studies aimed at producing a flexible sheet with high physical properties.

That is, an object of the present invention is to provide a method for manufacturing a fiber composite sheet that is extremely flexible and has high physical properties, and furthermore, to provide a method for manufacturing a raised sheet with a beautiful surface. .

That is, the present invention has the following configuration to achieve the above object.

That is, in a method of manufacturing a flexible sheet by applying a viscoelastic resin to a sheet containing attenuable fibers, first, a viscoelastic resin and a temporary filling substance are applied to a sheet containing attenuable fibers, and then solidified. , and then the thinning fibers constituting the sheet are thinned, and then a viscoelastic resin is further applied and solidified, and the temporary filling material is removed. It is something.

This will be explained in more detail below.

The constituent fibers of the flexible sheet according to the present invention include:
Contains at least atomizable fiber.

A finer fiber is a fiber that can be made finer by chemical, mechanical, thermal, or a combination thereof compared to before these treatments. Typical examples are polymer arrays as typified by Japanese Patent Publication No. 46-27775, and polymer blend fibers (including short fibril types, which have low physical properties in conventional methods). However, according to the method of the present invention, the physical properties can be improved).
Naturally, it also includes split-type fibers that can be split into a large number of thinner fibers by physical, chemical, thermal, or a combination thereof. Naturally, bimetals with the same ingredients but different molecular weights and their core-sheath types are also included.

In other words, the fiber constituent components include one or more components, and of course three or more components are also included. Next, the sheet in the present invention refers to knitted fabrics, woven fabrics, nonwoven fabrics, and those to which various binders and the like are attached. These sheets may be of any type as long as they contain atomizable fibers as a constituent component.

The proportion of the fibrilable fibers in the fibers constituting the sheet may be 100% fibrilable fibers. In addition, in the case of knitted fabrics, etc., it is also effective to use atomizable fibers as a percentage of the warp and weft constituent yarns. These may be appropriately selected depending on the knitting, texture of the weave, density of the nonwoven fabric, and other conditions. Particularly when raising a sheet to make a sheet with naps, it is an effective method to use atomizable fibers as the fibers to form the naps, especially from the standpoint of quality, cost, and physical properties.

These sheets are then provided with a mixture of temporary filler material and viscoelastic resin.

Viscoelastic resins include various types of polyurethane, various rubber substances such as NBR, and substances that exhibit viscoelastic behavior such as silicone rubber and fluorocarbon rubber, and various viscoelastic resins that can be used in synthetic leather are used. can. It is usually a polymeric material with a low elongation at break.
A material with a stress of 300% or more and 200Kg/cm ² or less at 100% elongation is used. (The above measurements use a film-like sample (maximum thickness 2 mm) that does not have internal structural defects such as stress concentration that would impair the original physical properties, and is not oriented in a specific direction. The measurement method was to cut out a sample 5 mm wide at 20°C ± 2°C and RH 65% ± 2%, make the sample length 2 cm, and
(pulled at a speed of cm/min). These viscoelastic resins may be used not only alone but in combination of two or more.

In the present invention, the temporary filling substance is applied together with the viscoelastic resin, and when only the temporary filling substance is removed in a subsequent process, only the temporary filling substance is selectively removed without dissolving and removing the viscoelastic resin. Any substance is acceptable as long as it is solid at room temperature and is solid at room temperature. For example, water, Alcohols with 15 or less carbons, esters with 15 or less carbons, ethers with 15 or less carbons, amines with 15 or less carbons, amides with 15 or less carbons, acetic acid or chlorinated acetic acid , chlorinated hydrocarbons having carbon atoms of 10 or less, and mixed liquids thereof. Among the liquids, one or more of the liquids is preferably a substance that is solid at room temperature and does not have a common solvent with the viscoelastic resin. used. Specific examples include cellulose-based substances such as methylcellulose, polyvinyl acetate, polyvinyl alcohol, and copolymers thereof. Another example is inorganic salts such as calcium carbonate. From the viewpoint of sheet shape retention, particularly preferred are cellulose-based materials such as methylcellulose, and polymeric materials such as polyvinyl alcohol and copolymers thereof.

The mixture of the temporary filling material and the viscoelastic resin may be mixed in an aqueous system or in an organic solvent system.
Both the temporary filling material and the viscoelastic resin do not need to be dissolved in the liquid, and may be in a dispersion system.

Regardless of whether or not the viscoelastic resin and the temporary filling material have a common solvent, it is more preferable that the mixing state of both be uniform. In particular, it is desirable that the viscoelastic resin remain in a porous structure or in a dispersed state after the temporary filling material is removed.

The mixing ratio of the temporary filling material and the viscoelastic resin (the ratio of solid content only, excluding the medium) is not particularly limited, but a mixing ratio of 3 to 95% by weight of the viscoelastic resin is particularly desirable. Preferably, it is 5 to 93% by weight. If the content of the viscoelastic resin is 3% by weight or less, the physical properties of the resulting product may become weak. This tendency is particularly strong in systems in which a temporary filling substance is further applied after the fibers are thinned. Therefore, the viscoelastic resin is 5
It is preferable to add more than % by weight.

On the other hand, if there is less temporary filling material, the softness will be insufficient. For this reason, it is desirable to contain the temporary filling material in an amount of 5% by weight or more, more preferably 7% by weight or more. Now, the amount of these mixtures applied to the sheet varies widely depending on the type of sheet, but
It is preferable that the viscoelastic resin be added in an amount of 0.5% by weight or more to the fibers constituting the sheet. If it is less than this, wear resistance and physical properties tend to be weak. In particular, when using a large amount of fibers that are thinned by removing one or more components by chemical treatment or the like as the fibers constituting the sheet, it is preferable to add a large amount, and it is desirable to add 1% by weight or more. In addition, from the viewpoint of texture, it is usually desirable for the content to be 50% by weight or less. Various conventionally known means such as impregnation, spraying, and coating can be used as the application method.

This treatment may cause some of the refinable fibers to become thinner. After applying the viscoelastic resin and temporary filling material, solidification is performed. Even if coagulation is dry coagulation,
Further, wet coagulation may be used, and there is no particular limitation. It can be appropriately selected depending on the solvent, dispersant, etc. of the viscoelastic resin used.

Next, the fibers constituting the sheet are thinned. In the present invention, the term "thinning" refers to making the material thinner than before treatment by chemical, thermal, mechanical, or a combination thereof, or forming it into a fibrillar state. In other words, it is not necessarily necessary to remove one or more components of the multi-component fiber, nor is it necessary to make the fibers all thinner in the fiber axis direction. Furthermore, it is not necessary to separate until the separation is clearly seen with the naked eye, and the process of thinning is when the basis for thinning through subsequent simple processing is starting to form.

A typical thinning method in the present invention is to treat composite fibers or polymer blend fibers with a so-called sea-island structure, which are made of two or more polymer components with different solubility to chemicals, by treating them with chemicals to remove the dissolved components. Removal is very effective. Using this method, extremely fine fibers can be stably produced. This result is particularly useful for producing very flexible sheets. In addition, in the case of composite fibers made of polymers of two or more components that differ in their swelling properties against heat, other liquids such as water and swelling agents, peeling can occur between multiple components through swelling treatment, etc., using the swelling difference. It is also effective to make the size smaller. Furthermore, it is also effective to add a foaming agent or the like to the fibers, foam them, and thin them into a fibril shape or the like. The fineness after fineness is preferably 0.8 denier or less, particularly preferably 0.3 denier or less, considering the texture.

When fibers are divided into multiple fine fibers by thinning (for example, in the case of sea-island type composite fibers, polymer blend fibers, or exfoliation type fibers), one component is removed from core-sheath type composite fibers or bimetallic type composite fibers. Although there are cases where the fibers are not divided into a plurality of fibers even when the fibers are thinned, such as when the fibers are dissolved or decomposed and removed, the former case is usually preferred.

A viscoelastic resin is applied to the thus thinned sheet. The viscoelastic resin may be the same as that applied previously, or may be of a different type. However, it is preferable that the temporary filling material be dissolved or dispersed in a liquid that does not easily dissolve it. The amount granted is
Although it varies widely depending on the type of sheet, it is preferable that the total amount including the viscoelastic resin applied earlier is 3% or more. If it is less than this, the strength will be weak and wrinkles may occur frequently. However, if the sheet is made of a nonwoven fabric and more than half of the fibers constituting the nonwoven fabric are to be thinned, it is preferable to add 9% or more of the viscoelastic resin. After thinning, a viscoelastic resin is further applied and solidified. This coagulation may also be the same dry coagulation or wet coagulation as the coagulation performed after applying the viscoelastic resin and the temporary filling material, and if the previous coagulation is dry, it may be wet coagulation, or if it is wet, it may be dry coagulation. It may be a wet/dry combination such as the above, and is not particularly limited. It may be selected appropriately depending on the solvent, dispersant, etc. of the viscoelastic resin used. Next, the temporary filling material is removed. There are various removal methods, but the most common method is the dissolution method. It goes without saying that a portion of the temporary filling material may be removed during the solidification process. The sheet thus obtained has very high physical properties and is highly flexible.

Additionally, the sheet is brushed if necessary. In many cases, the flexibility is further increased by raising the hair. Furthermore, a grained leather-like sheet can be obtained by providing a grained layer with or without raising.

The raising method can be carried out by various conventional methods such as so-called mechanical raising, buff raising, paper buff raising, etc.
There are no particular limitations.

According to the present invention, it is possible to obtain a fiber composite sheet that is flexible but has high physical properties such as higher abrasion resistance and tear resistance, as well as a raised sheet thereof. Since it is possible to maintain the same level of strength, it is possible to achieve great effects such as being able to practically produce thinner products. In addition, the raised sheet obtained by the present invention is extremely elegant, difficult to remove hair, and has high durability such that the surface does not easily change.

Although the details of why a sheet with a soft texture and high physical properties can be obtained by the present invention are unknown, the outline thereof is thought to be as follows.

That is, by performing the thinning treatment after applying the mixture of the temporary filling material and the viscoelastic resin, the previously applied viscoelastic resin is weakly bonded to the fibers, so that it is effective in softening the sheet. On the other hand, since a viscoelastic resin is added even though it is a weak bond, it has a corresponding effect of improving physical properties. On the other hand, the viscoelastic resin applied later bonds more strongly with the fibers, but it bonds moderately due to the action of the temporary filling material. In addition, it also appropriately bonds with the previously applied temporary filling material. This has the effect of softening the texture and improving physical properties. especially,
It is thought that this effect is achieved because the temporary filling material optimizes the bonding between the fibers, the viscoelastic resin, and the viscoelastic resins, resulting in a structure that prevents stress concentration.

The following will be described in more detail with reference to Examples.

Example 1 The island component is polystyrene copolymerized with polyethylene terephthalate and the sea component is 20 mol% of 2-ethylhexyl acrylate, the ratio of the island to the sea is 50:50 by weight, and the fineness is 4.5 d (number of islands is 16). The polymer mutual array was made into a web and needle-punched to make a non-woven fabric. After this, it was treated with hot water at 80°C. At this time, the area decreased by 23%. The weight of this felt is 630 g/m ² . Next, this felt was impregnated with a mixture of 5% by weight of polyvinyl alcohol as a temporary filling material and 5% by weight of emulsion polyurethane partially cross-linked in three dimensions as a viscoelastic material (the remaining 90% by weight was water), and hot air was applied to the felt. It was dry solidified.
The amount applied was 11% by weight of the mixture based on the fibers. After that, the sea component was removed using Triclean to thin the fibers. The removal rate was 98.5% by weight. After that, it was heat-treated at 150°C for 10 minutes, and then a 7% by weight solution of polyurethane (solvent dimethylformamide) was added, wet coagulated, soaked in 85°C warm water, and passed through a mangle 15 times to remove polyvinyl alcohol. .

The total amount of polyurethane applied was 41% by weight based on the fiber. This sheet was sliced into two pieces, buffed to make a raised sheet, and further dyed to make artificial leather. Each process was carried out smoothly without any problems. The obtained product is highly flexible (bending strength is 59 mm vertically and 44 mm horizontally according to the JIS L-1079 Clark method), and has a tight nap, with an abrasion strength of 577 times and a tear strength of 577 times. It had high physical properties of 1.0Kg horizontally and 1.2Kg vertically. The weight of this product was 215 g/m ² and the thickness was 0.88 mm.
Abrasion strength was measured by abrading the sheet surface with a rotating nylon brush, measuring the number of rotations until the sheet was torn, and using the number of rotations as a measure of abrasion resistance.
Tear strength was measured according to method C of JIS L-1079.

Comparative Example 1 A 10% polyvinyl alcohol (PVA) solution was applied to the felt that had been shrunk by the hot water treatment used in Example 1, and it was dry coagulated with hot air. A 15% by weight polyurethane solution was applied using formamide (DMF) as a solvent. The amount of polyurethane applied is fiber 48
It was in weight%. The weight of this product is 220g/
m ² and thickness was 0.90 mm. We also performed slicing, buffing, and dyeing. The texture is relatively flexible (JIS
L-1079 The bending resistance is vertical 63 using the Clark method.
mm, width 45 mm), but the abrasion strength was 225 times,
The tear strength was 0.5 kg horizontally and 0.7 kg vertically, indicating low physical properties. Also, the nap was long and curly, so it wasn't a very good synthetic suede.

Example 2 The island component is nylon-6, the sea component is polystyrene copolymerized with 18 mol% of 2-ethylhexyl acrylate, island/sea = 55/45 (weight ratio), fineness
Using a 5.5D polymer array, a web was made and needle punched to make a nonwoven fabric. After that, it was treated with hot water at 80°C. At this time, the area decreased by 29.5%. The weight of this felt was 595 g/m ² . Next, this felt was impregnated with a mixed solution of 7% by weight of polyvinyl alcohol (PVA) and 7% by weight of the emulsion polyurethane of Example 1 (remaining water), and dry-coagulated with hot air. The total amount of PVA and polyurethane applied was 15% by weight based on the fiber.

Next, the sea component was removed using Triclean to thin the fibers. The removal rate was 98.7% by weight. Next, heat set at 150℃ for 10 minutes, impregnate with a 12% by weight solution of polyurethane in dimethylformamide (DMF), wet coagulate, and desorb.
I did PVA. The total amount of emulsion and solution polyurethane applied was 38.5% by weight based on the fiber. This sheet was sliced, buffed, and further dyed to create suede-like artificial leather. The weight of this product was 230 g/m ² and the thickness was 0.75 mm. The product is highly flexible (according to JIS L-1079, Clark measurement method, bending resistance is 58 mm vertically and 45 mm horizontally), and has a beautiful, fine-grained nap, and the wear resistance is 1235 times. , tear strength is vertical
It was very strong, weighing 2.4Kg and 1.5Kg horizontally.

Example 3 The shrink felt of Example 1 was used as a temporary filling material.
The emulsion polyurethane of Example 1 was used as PVA and a viscoelastic resin, and the former was mixed to 10% by weight and the latter was 4% by weight (the rest was water), impregnated, and dry coagulated with hot air. The amount applied was 16% by weight of the mixture based on the fibers. After that, the sea component was removed using Triclean and the fibers were made finer. The removal rate was 98.5% by weight. There were no problems with the process. Then DMF solution polyurethane 10% by weight
The solution is impregnated, dry coagulated with hot air, and then desorbed.
I did PVA. The total amount of emulsion polyurethane and solution polyurethane deposited on the fiber was 43% by weight. The obtained sheet was sliced, buffed, and further dyed to produce suede-like artificial leather. The basis weight of this product is 215g/m ² and the thickness is 0.80
It was warm in mm. The product is highly flexible (JIS L-1079
The bending resistance is 51 mm vertically and 51 mm horizontally using the Clark method.
39mm), it has a beautiful, fine-grained nap, and has a high abrasion strength of 750 times and tear strength of 2.9Kg vertically and 1.8Kg horizontally.

Comparative Example 2 The shrink felt of Example 1 was impregnated with the emulsion polyurethane of Example 1 at a concentration of 10% by weight. The amount applied was 6% by weight based on the fiber. Thereafter, when an attempt was made to remove the sea component with trichlene in the same manner as in Example 3, the emulsion polyurethane expanded significantly and the sheet slipped and was difficult to pass through the mangle. Further, as in Example 3, the sea components were not sufficiently removed by the sea removal treatment, so the number of sea removal treatments was doubled. As a result, we were finally able to achieve a 98% removal rate for sea components. Next, an 8% by weight solution of polyurethane in DMF solution was applied by impregnation, wet coagulation, and further DMF removal was performed. The total amount of emulsion solution polyurethane deposited in the mixture was 45% by weight on the fibers.

The following procedure was carried out in the same manner as in Example 3 to obtain suede-like artificial leather. The basis weight of this product is 220g/m ² and the thickness is
It was 0.80mm. The nap of the product was short, the polyurethane was exposed in some places, it was very irritated, and the texture was poor, so it could not be called a very good suede. Only the abrasion strength was 700 times, but the texture was hard (JIS L-1079 Clark measurement method, bending strength was 70 mm vertically and 52 mm horizontally), and the tear strength was low at 0.5 kg vertically and 0.8 kg horizontally. It was hot.

Example 4 A sheet material to which the mixture of the viscoelastic resin and temporary filling material of Example 3 was applied was immersed in a 25% aqueous solution of sodium sulfate, wet coagulated, further dried, and the fibers were thinned. It was carried out in the same manner as in 3. There were no particular problems in the process.

Next, the DMF solution polyurethane of Example 3 was impregnated, wet coagulated with a 20% aqueous solution of DMF, and subsequently PVA removed with hot water at 90°C.

The total amount of emulsion polyurethane and solution polyurethane deposited on the fiber was 45% by weight.

Thereafter, it was treated in the same manner as in Example 3 to obtain suede-like artificial leather.

This product had a basis weight of 221 g/m ² and a thickness of 0.82 mm. The product is highly flexible (according to JIS L-1079 Clark method, the bending resistance is 46mm vertically and 33mm horizontally.
mm) and has an extremely fine and beautiful surface, and has an abrasion strength of 680 times and a vertical tear strength of 3.5 times.
It was extremely strong with a weight of 2.3 kg and a horizontal weight of 2.3 kg.

Claims (1)

[Claims] 1. In a method of manufacturing a flexible sheet by applying a viscoelastic resin to a sheet containing attenuable fibers, first, a viscoelastic resin and a temporary filling substance are applied to a sheet containing attenuable fibers and solidified, Thereafter, the attenuable fibers constituting the sheet are attenuated, and then a viscoelastic resin is further applied and solidified,
A method for producing a flexible sheet characterized by removing a temporary filling substance.