JPH0153397B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a new synthetic leather.
In other words, the surface layer, which corresponds to the grain layer of natural leather, is a fluff-free knitted fabric (knitted fabric or woven fabric) made of modacrylic fibers with a deep and clear three-dimensional pattern with a gentle luster. The corresponding base layer is composed of a soft thermoformable synthetic resin foam, and the convex portions on the surface are fabric surfaces, and the concave portions formed by digging into the base layer have a smooth shape that can be called a skin surface. , relates to synthetic leather consisting of a strikingly new composition. Traditionally, it has been used as an alternative to natural leather for clothing, furniture,
Synthetic leather, which is widely used as a material for bags, bags, shoes, etc., mainly has a base fabric layer (woven, knitted, non-woven) that corresponds to the net layer of natural leather, and a grain layer that corresponds to the grain layer of leather. It has a two-layer structure with a resin layer coated or bonded. The resin layer is made of porous or non-porous synthetic resin such as polyvinyl chloride, polyurethane, polyamide, or polyamino acid, which has a texture and physical properties similar to natural leather. Surface treatment is performed. Among these, vinyl chloride leather (vinyl leather), which uses polyvinyl chloride in the resin layer, or sponge leather, which uses polyvinyl chloride foam, is distinguished from synthetic leather in the narrow sense as imitation leather in Japan. It is inexpensive, versatile, and used in extremely large quantities. However, it is heavier than urethane-based synthetic leather or fabric, which is a disadvantage when used for clothing and portable items such as bags and bags.Also, it has been used for general purposes for a long time, so it is no longer used today. The image of cheap, low-quality products has become widespread among consumers, and they are beginning to dislike them. Synthetic leather that uses polyurethane or polyamide for the resin layer has an appearance and feel that is more similar to natural leather than vinyl leather.In particular, synthetic leather uses nonwoven fabric made of ultrafine fibers for the base layer and polyurethane with continuous fine pores for the resin layer. The so-called artificial leather used has a structure and flexibility that is almost the same as natural leather. Then, the surface of the resin layer is coated, patterned by printing, and the texture is changed by various surface treatment agents.
In some cases, secondary processing such as buffing to create suede is performed, and a wide variety of synthetic leathers have been devised by varying the combinations of the base fabric layer and resin layer, and by improving each of them. . However, these synthetic leathers are intended to reproduce natural leather, and their appearance and texture are not much different from natural leather. On the other hand, a wide variety of fabrics are also used in clothing, furniture, bags/bags, shoes and other footwear, wall coverings, and other miscellaneous goods for which the vinyl leather and synthetic leather are used. The difference between this fiber knitted fabric and synthetic leather or vinyl leather is that the former has a knitting structure, so the surface appearance, texture,
It has a wide variety of colors and a surface with excellent physical and chemical strength. However, it does have some drawbacks, such as the surface staining is inferior to the synthetic leather that forms the film surface. However, vinyl leather and synthetic leather are also included in textile fabrics in a broad sense as a type of coated fabric, and it is undeniable that there is a greater variety of fabrics. By the way, if we look at trends in past trends, there was a time when leather and synthetic leather preferred the appearance and texture of the glossy film surface represented by enamel, and a time when the appearance and texture of the fabric surface was preferred. There have been alternating periods in which people preferred Particularly in recent years, trends have been changing rapidly and there has been a tendency for people to prefer newer items, so there is a strong desire to provide materials that match these trends. For example, suede-like synthetic leather, Jiaguard woven fabric, and simple, shiny, lightweight taffeta are used as materials that have an element intermediate between the surface of cloth and the surface of film. Also,
Materials in which the fabric surface is oil-coated or transparent or translucent polyurethane film is directly coated on thin fabric also allow the structure and color of the underlying fabric to appear on the surface through the film layer, and are in line with recent clothing sensibilities. It has been well received as a. However, these materials cannot fundamentally be said to deviate from the conventional techniques of cloth and synthetic leather, and have recently become increasingly disliked. The present invention was made from the viewpoint of developing new materials as described above, and is different from conventional synthetic leather that aims to be natural leather.
The purpose of the present invention is to provide a new synthetic leather that has completely different structures, especially the surface layer, and has both a skin surface and a cloth surface, and its appearance and feel. Hereinafter, the present invention will be explained in detail based on the drawings. FIG. 1 shows an example of synthetic leather 1 according to the present invention. As shown in Figure 2 (an enlarged cross-sectional view of the X-X section in Figure 1), this is a polyacrylic fiber, especially the product name "Kanekalon" (manufactured by Kanegafuchi Chemical Industry Co., Ltd.).
The surface layer is a fabric 2 with a satin texture made of modacrylic fiber known as "Dynel" (manufactured by Union Carbide Co., Ltd.), and a foam 3 of a 1,2-polybutadiene resin alone or a polymer blend containing this as one component ( An embossed pattern is applied to the fabric side of the foam laminate (formbacks) 4, which has a base layer of ``1,2-PBD foam'' (hereinafter referred to as "1,2-PBD foam"), in which the convex portions A are the fabric surface and the concave portions B are the smooth surface. It is what it is. In the figure, reference numeral 5 is an adhesive layer, and 6 is a knitted fabric serving as a reinforcing backing material. In addition, the recess B is formed using dielectric heating using high frequency waves, and the 1,2-PBD foam in this area is softened and compressed according to the heating mold, and the unfoamed 1,2-PBD resin is converted to the depth corresponding to the depth. It becomes close. On the other hand, modacrylic fibers are also softened or partially melted by the heating mold, and 1.
2-While stretching and deforming along the PBD foam,
The bottom part has a thin film-like appearance. However, the other parts that are not pressurized do not undergo any changes, the surface remains as cloth, and the 1,2-PBD foam retains its cushioning effect in its original state, and the convex part A and concave part B Boundaries are clearly visible. By the way, the present inventor has previously invented a three-dimensional patterned cloth material consisting of the same structure as the present invention (patent application filed in 1983).
−102744). However, modacrylic fibers are generally in the form of staples, and the fabric surface inevitably becomes fluffy. This fuzz remains as it is on the surface of the cloth, which is a convex part, and makes the deep embossed pattern unclear, and in the concave part, the fuzz becomes an obstacle, making it difficult to form a clear and glossy skin surface. In extreme cases, the embossed pattern may become blurred and not visible at all from a certain viewing angle, resulting in a very low commercial value. Furthermore, the three-dimensional patterned cloth material only needs to have irregularities formed by embossing on the surface of the cloth, without considering any limitations such as weaving structure or yarn usage. Therefore, as a result of further research, the inventor of the present invention found that by treating the surface of the fabric with fluff and selecting an appropriate fabric, it is possible to create a fabric with a deep and clear pattern that is not just a three-dimensional patterned material, but has a gentle luster with no fluff on the surface layer. The present invention has led to the provision of a new material that has an uneven pattern and has an appearance, feel, and physical properties similar to synthetic leather. That is, as mentioned above, conventional synthetic leather is typified by urethane synthetic leather in which a film of polyurethane or the like is formed on the surface layer, but the product of the present invention has a surface layer that has the appearance and feel of synthetic leather. It should also be called modacrylic synthetic leather, which is made of modacrylic fiber fabric with certain conditions. This is different from conventional skin-like products made of resin film, and has the appearance and feel of both conventional synthetic leather and fiber fabric, with an embossed fiber fabric surface layer and skin-like recesses. It is a material that meets consumer needs, and because the surface is made of cloth, it has excellent physical strength. Therefore, the fabric used in the present invention is a knitted fabric using modacrylic fiber (vinyl chloride acrylotrile copolymer fiber), which has been subjected to fluff treatment, and has a grain layer (skin layer) of the leather before and after embossing. It is necessary that the physical properties are similar to those of .
The fluff treatment may be done by using a calender roll to lay out the fluff.
It is most preferable to remove fuzz by burning the yarn or cloth. In addition to the satin weave shown in FIG. 1, the fabric is preferably one that has a relatively dense and thin texture, such as a broad weave (plain weave), and has a flat texture with little change in the fabric surface. The reason why the texture is dense is that the base resin (soft foam) does not protrude from the gaps between the threads in the embossed part in a peeled state. Furthermore, the thin and flat surface provides smoothness and flexibility comparable to the skin layer of natural leather before and after embossing, and in particular allows the formation of a thin and soft film layer after embossing.
It also needs to be soft to the touch.
In order to satisfy the above conditions, it is necessary to select the thread thickness, basis weight, and weaving or knitting structure as described below. If the fabric is knitted, synthetic leather with stretchability can be obtained. By the way, even if the physical properties of a single fiber or yarn are harder than those of a soft film, depending on the structure of the fabric and appropriate processing conditions, it is possible to achieve drapability similar to that of a low modulus soft material. The ability to provide certain properties is an important point in making this structure match the texture of leather. Modacrylic fibers have much better thermoformability than other synthetic fibers such as nylon and Tetron. In general, the thermoformability of fibers is expressed as Pt (plasticity), which is expressed as "elongation at break / tensile strength ×
100'', but in the case of modacrylic fibers, the value changes significantly at temperatures above 120℃, and at room temperature it is approximately 80℃.
It will be doubled. Also, the energy that distorts the fibers is TI
(toughness index), and if this value is small, less energy is required to distort the fiber during molding, resulting in better thermoformability, but for modacrylic fibers, the TI at 50% elongation is 1/1 of that at room temperature at 120°C. Some fibers have a fiber diameter of around 10, making them extremely easy to thermoform compared to other fibers. The appropriate temperature for embossing is 80-160℃.
However, at temperatures above 140°C, the embossed surface becomes hard due to melt hardening, changes color, and deteriorates in texture and appearance. Therefore, the optimum processing temperature is 140°C or less, especially 100 to 130°C, and in this case, the texture of the concave surface B is smoothed while retaining the softness of the original fabric. Therefore, it is also necessary that the thermoforming temperature of the soft foam of the base layer, which is integrated with the surface layer by embossing, is within the range of 80 to 160°C, especially 100 to 160°C.
A temperature of 130℃ is optimal. From this point of view, soft foams include, in addition to the aforementioned 1,2-PBD foam, thermoplastic polyurethane elastomer foams, partially crosslinked ethylene-vinyl acetate copolymer foams, and soft (partially crosslinked) polyvinyl chloride foams. Foams and other thermoplastic elastomer foams are used. Next, the reason why the resin layer of the present invention is limited to a soft foam will be explained. In general, the modulus of fibers in the fiber direction is higher than that of plastic film, but woven and knitted fabrics have a low modulus due to the degree of freedom of the structure consisting of entangled fibers (yarns), and in some cases It exhibits a softer drape than thin soft plastic film. However, when this fabric is bonded to a plastic film or sheet, the degree of freedom of the tissue, mainly in the plane direction, is restricted by the physical properties of the film or sheet in the plane direction. (On the contrary, this film or sheet is constrained by the physical properties of the fabric in the plane direction.) If this film or sheet is semi-rigid or rigid,
The fabric, which has excellent drapability, becomes a rigid body with no freedom in the plane and vertical directions. Therefore, in order not to impair the texture of the cloth, films and sheets must have a low modulus equivalent to or higher than that of cloth, and must have elasticity and
It must be made of a soft material with plenty of elasticity.
A foam (cell) is the most ideal soft material, and if the expansion ratio is increased, a material with extremely low apparent modulus can be obtained. Then, it expands and contracts well with a small external force, making it soft and highly elastic. Since the present invention embosses the laminate in the vertical direction, the concave portions are compressed and become denser and harder. Therefore, a foam with relatively high magnification (5 to 20 times) is required, and the density of the resin is low. In particular, in order to obtain a deep embossed pattern, the sheet must be thick, and in order to reduce weight, it is necessary and sufficient that the resin layer in the present invention be a foam. The thickness of the foam is preferably about 0.6 to 2.0 mm, although it depends on the expansion ratio. In addition, when foam bags made by laminating soft foam on fabric are embossed from the fabric surface, the fabric and soft foam are molded at the same time, which buffers the thermoforming of the modacrylic fiber fabric and reduces the expansion magnification of the molding. It is possible to obtain a material in which the hardness of large concave portions and small convex portions is almost the same. If the soft foam is embossed without backing, the concave portions will harden and the physical properties will change, resulting in a decrease in tensile strength and tear strength, making it unusable for practical use. Further, the great practical advantages of foam bags are that they have a warm feel, have heat retention properties, and are lightweight and easy to handle when used in portable items such as bags and bags. As mentioned above, there are various kinds of flexible foams that satisfy these conditions, but in particular, 1,2-polybutadiene resin or a polymer blend containing this as one component is processed by, for example, an ultraviolet crosslinking method before foaming. Therefore, 1,2-PBD obtained by pre-crosslinking so that the gel fraction is within the range of 10 to 75% (gel fraction after 15 hours of boiling toluene) and then foaming by the blowing agent decomposition method. Foams have a suitable temperature for thermoforming.
It is one of the most preferred fibers because it has a temperature of 80 to 130°C and can be heated dielectrically like modacrylic fibers. Furthermore, the foaming ratio can be freely changed over a wide range, and it has rubber-like behavior with high elasticity, permanent elongation, extremely low compression set, and good recovery properties, and is lightweight. However, it is also possible to use other flexible foams, such as flexible polyvinyl chloride foam, which is somewhat heavier but inexpensive. These foam laminates may be molded in a molding temperature range of 80 to 160° C. for modacrylic fibers in accordance with the softening point of each foam. In addition, these soft foams are desirably endless from the viewpoint of manufacturing efficiency, and need to be stretchable to prevent cracks from forming at the edges of the pattern during embossing. On the other hand, adhesives for laminating fabric and soft foam include urethane, acrylic copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, etc., which have good adhesion between modacrylic fiber fabric and foam. An excellent one is preferably used. Also,
The backing material adhered to the back side of the foam is made of knitted fabrics, woven fabrics, and non-woven fabrics, but these backing materials have the purpose of protecting the foam and increasing its physical strength such as overall tensile strength and tear strength. It is. Next, the present invention will be explained in more detail with reference to Examples. Example Warp #40 single yarn 150/inch, weft #30 single yarn 65
A fabric (weighing approx. 160 g/m ² ) woven with 5 sheets of satin weave using yarn per inch (all products of Dal's modacrylic fiber "Kanekalon") is burnt on one side using a burner method, and then beamed with a cationic dye. After dyeing, the fabric was subjected to softening and water-repellent treatments to obtain a fabric with almost no fuzz and a glossy satin surface.
Next, the non-baked side of this fabric and an endless 1,2-PBD foam [trade name "Calsoft", manufactured by Takiron Co., Ltd.] (specific gravity 0.1 thickness 1 m/m) were
Lamination was carried out using a two-component solvent type polyurethane adhesive using a reverse coater method. Also, on the other side of the foam, nylon tricot (40d/
28G) using the same adhesive,
A foam laminate was obtained in which the intermediate layer was a foam. This foam laminate was placed directly under a mold (in which a desired pattern with many relatively fine convex parts was engraved) fixed to the upper press plate of a high-frequency welder that had been preheated to 80°C. Feed with the plate facing up, immediately close the press and pressurize (approximately 30
kg/ ^cm2 ). At the same time, a high frequency of 13.56MHz is oscillated to raise the temperature of the pressurized part to about 120℃ and emboss it (2 to 5
seconds), then cooled at mold temperature (80° C.) for 2-5 seconds. After that, open the press and pull out the embossed fabric by the pitch of the mold (the cycle during this time varies depending on the embossed pattern, but it takes about 10
Embossing was repeated intermittently to obtain synthetic leather with a clear three-dimensional pattern and a gentle luster. The convex portions of the synthetic leather either retain the original structure of the modacrylic fiber fabric as they are, or are deformed into a somewhat open state depending on the state of the pattern around the convex portions. In addition, the recesses embossed with fine patterns,
The fibers become soft or semi-molten to the extent that they hardly retain their original structure, and when the convex part of the mold is mirror-like and flat, a shiny skin appears (second
figure). The part that exhibits this skin condition can be called a special synthetic leather that has a completely different appearance from conventional synthetic leather or textile fabrics, and together with the flat surface of the fabric, the entire surface resembles a unique leather. Texture/
It gives a feeling. The embossed design gives the entire laminated body a relaxed, “bone” feel.
It is flexible, has no horns, has appropriate cushioning and drape properties, is lightweight, has a warm feel, and has an excellent surface abrasion resistance. In the case of other soft foams that cannot be heated by dielectric, normal heating methods such as infrared heating and hot air heating are used, but in any case, the pattern engraved on the mold is repeated. When the seams are eliminated, synthetic leather having a long three-dimensional repeating pattern is obtained. On the other hand, if this embossing is carried out using a roll (there is a method in which the foam laminate is heated to a predetermined temperature and then embossed with a cooled roll, or a method in which the foam laminate is embossed with a roll that is heated at room temperature), there is a continuous embossing process. Processing becomes possible, which increases production efficiency, but unless the depth of the unevenness of the roll is greater than the thickness of the foam laminate, the convex surface of the embossed body, that is, the fabric surface, will also be heated and the entire surface will become glossy and contrasty, as if it had been calendered. There is a risk that it will disappear. Next, Table 1 shows the properties and evaluations of synthetic leathers obtained by varying the texture and yarn residue of the fabrics constituting the surface layer of the synthetic leather of the present invention. These are examples of products that can achieve the above object of the present invention, and the condition, texture, and evaluation of the three-dimensional pattern shown on the right side of the table are all obtained by fabricating synthetic leather using the method shown in the example above.

【table】

【table】

[Table] This is an observational evaluation of the items listed below.
In addition, among each sample, ~ is a satin weave, ~ is a plain weave, is a twill weave, * is a satin weave, is a multicolored weave (plain), and * is a knitted fabric. Also, the sample...
indicates the difference in the presence or absence of hair burning, ~ indicates the difference and limit due to the thickness and number of threads, and ~ indicates the specificity due to the tissue. From the experimental results shown in Table 1, modacrylic fiber fabrics useful in the present invention have a relatively dense and thin texture, a flat fabric surface, and are made of different textures and threads with little change. It turns out that it is good. Even if the texture is dense or thin, the fabric has large irregularities or lively patterns, such as bevel, twill weave with prominent twill lines, feuille, honeycomb weave, or dobby or jiya guard with small patterns. , Chambray, and other items with different thread colors will not stand out if they have a fine embossed pattern. Therefore, in this case, the embossed pattern should be monotonous and rough, and should be chosen to match the interesting texture of the cloth surface. On the other hand, in the case of plain weaves such as broadweave, satin weave, twill weave with inconspicuous twill lines, and knitted fabrics such as jersey, the fine embossed patterns are also very noticeable, and the embossed patterns can vary on the fabric surface. can bring about significant changes. In addition, even if the texture is dense and thin, and the fabric surface is flat and has a texture with little change, if the fluff on the surface has not been removed by burning, the embossed concave surface will have fluff in the same way as the convex surface. Since it is fastened (the fluff is particularly noticeable when viewed from the horizontal direction), the pattern is not clear and the luster is poor. Therefore, depending on the angle, the pattern is barely visible, and it does not have the appearance of synthetic leather. Therefore, removing fluff from the fabric surface by burning is an essential requirement of the present invention. However, in the case of filament yarn, the side surface of the yarn is observed, and there is no fuzz at all, which meets the purpose of the present invention. Even if the thread structure is the same, the feeling of the three-dimensional pattern obtained will differ depending on the gloss of the fiber (dull, semi-bright, bright), and the glossier the surface of the synthetic leather obtained. The gloss will also improve. Furthermore, as is clear from the table, in order to maintain the soft texture of synthetic leather, the thickness of the threads is not very thick (approximately 20/1 or more), and the number of threads is not too large (approximately 20/1 or more). 80-300g/ ^m2 ) is better. This is because if the thread is too thick, the embossed material will become stiff, and similarly, if the basis weight is too high, the structure (woven,
This is because the embossed surface becomes hard and loses flexibility regardless of the type of material used (ed.). In addition, fabrics with a small number of fibers or a fabric with a coarse structure that is transparent are not preferable because the underlying foam may come out of the texture during embossing. From the above, we believe that a fabric with an appropriate basis weight and a dense structure made of relatively thin threads can be used as a soft foam and a high-quality three-dimensional surface that retains the flexibility of the fabric and is engraved with a fine uneven pattern. It can be said that this is the most preferable synthetic leather with a pattern. It should be noted that when the fabric used in the present invention is plain, the uneven pattern is more noticeable and gives a subdued feel. It is also possible to create even more variation on the cloth surface by combining the color pattern and the uneven pattern, such as by creating mountains or conversely, creating valleys in the concave areas. As described in detail above, the present invention uses a knitted fabric made of modacrylic fiber, which is a type of polyacrylic resin, which has a relatively dense and thin texture, but whose surface has been fluffed, and which is formed at a molding temperature of The fabric side of the foam laminate has a soft foam of thermoplastic synthetic resin similar to modacrylic fiber as the base layer, and the convex portions are on the cloth side and the concave portions are on the smooth side (in case of multi-stage depending on the embossed pattern of the mold). It has an embossed pattern. Therefore, the surface layer has a gentle gloss with no fluff and a deep, clear uneven pattern, and the concave surface is skin-like, giving it the appearance and feel of both conventional synthetic leather and textile fabric, and a unique feel and feel that is similar to synthetic leather. Synthetic leather with good physical properties and excellent physical strength can be obtained, and can fully meet the recent demands for new materials.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an example of the synthetic leather of the present invention;
FIG. 2 is a partially enlarged sectional view taken along line X--X in FIG. 1. 1...Synthetic leather, 2...Fabric, 3...Foam,
4... Foam laminate, 5... Adhesive layer,
6... Reinforcement backing material, A... Convex portion, B... Concave portion.

Claims (1)

[Scope of Claims] 1. A textile fabric made of modacrylic fibers, the surface layer of which is treated with fluff using filament yarn or spun yarn, and a soft foam of thermoplastic synthetic resin having a molding temperature of 80 to 160°C. A synthetic leather having a three-dimensional pattern surface, characterized in that an embossed pattern is applied to the fabric side of a foam laminate having a body as a base layer, in which convex portions are the fabric surface and concave portions are the smooth surface. 2. Synthetic leather having a three-dimensional patterned surface according to claim 1, which is made by laminating a reinforcing textile fabric on the back side of a soft foam.