JPS6142019B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a fibrous sheet with excellent three-dimensional color appearance and a method for producing the same. More specifically, by stamping a fibrous substrate made of a porous polymer containing a colorant and a fiber aggregate, or a fibrous substrate having a non-porous coating layer thereon under specific conditions. The present invention relates to a fibrous sheet with excellent three-dimensional color impression and a method for producing the same. Fibrous sheets made of polymers such as polyurethane elastomer and polyvinyl chloride, or aggregates of these and fibers, can be used as substitutes for natural leather for shoes, clothing, bags, interior materials, book covers, camera cases, balls, decorations, industrial materials, etc. It is widely used in all fields. In order for the fibrous sheet to be used in such a wide variety of fields, it goes without saying that it must have excellent physical properties and texture to suit each application, but it also must have excellent surface color and embossed patterns. Because it greatly affects the product value,
It is very important to respond to user requests. Particularly in the fields of shoes, clothing, bags, etc., fashionability is important, and improvements in appearance, that is, higher quality products, are strongly discouraged. In response to these demands, the methods currently in use include gravure rolls engraved with a certain pattern to give a luxurious look to so-called silvered leather-like sheets with a porous polymer coating layer on the surface. This is done by complicated means such as adding shading or coloring, then embossing to create an uneven pattern, and then coloring the protrusions. Or, by applying multiple colored layers and removing a part of the outermost colored layer by rubbing,
Methods such as adding light and shade of color are used. However, in the case of a fibrous sheet made of a fiber aggregate and a porous polymer, even if the colorant is applied with a gravure roll like a sheet with a surface coating layer, the absorption and penetration of the colorant is very good. It is not easy to achieve a good coloring or a surface with a good tone. In addition, the boundaries of the patterned colored parts should be clearly distinguished,
Furthermore, it is difficult to emboss the same shape as the patterned colored portion. Therefore, simply adding shading of color on the same plane results in a lack of three-dimensional color impression, making it impossible to obtain a fully satisfactory product. Therefore, in order to obtain a high-quality product with good workability and excellent three-dimensional color impression, the present inventors investigated a wide range of finishing methods. By pressing a fibrous substrate consisting of a fibrous body or a specific fibrous substrate consisting of this and a non-porous coating layer under specific conditions not conventionally performed, the concave portion changes color and becomes darker, creating a three-dimensional shape. The present invention was accomplished by discovering that a fibrous sheet with excellent color impression can be obtained. That is, the present inventors used a fibrous substrate obtained from a porous polymer containing a colorant and a fiber aggregate,
By performing embossing under conditions stronger than conventional mechanical embossing methods, at a temperature and pressure sufficient to crush at least the porous polymer in the surface layer and make it transparent, a fibrous sheet with an uneven pattern can be obtained. The difference in specific gravity between the surface of the concave part and the concave part is 0.1 or more, the difference in depth between the concave part and the convex part is 80μ or more, and the K/ By making the difference in the values of S (where K is an absorption coefficient and S is a scattering coefficient) to be 1.0 or more, a fibrous sheet that is effective as a substitute for natural leather with excellent three-dimensional color feeling can be obtained. I found out that it can be done. That is, in the present invention, the inside of the fiber assembly is filled with a wet-coagulated porous material made of a polymer mainly composed of polyurethane elastomer, and the polymer contains a coloring agent of 1 to 300% by weight based on the polymer. The K/S value of the surface is 0.5 to 7.0, and the apparent specific gravity is
0.2 to 0.9 at a temperature and pressure sufficient to crush the porosity of the polymer mainly composed of polyurethane elastomer in the surface layer and make it transparent, and the apparent specific gravity (d ₂ ) of the recesses and convexity The difference (d ₂ - _{d 1 )} in the apparent specific gravity (d ₁ ) of the part is 0.1 or more, and the difference ( _{K 2}
-K ₁ ) is 1.0 or more and the depth is 80 microns or more. By pressing with a strength that satisfies the conditions, a fibrous sheet with excellent three-dimensional color feeling that integrates three-dimensional effect and color difference is produced. can get. In other words, the fibrous sheet of the present invention has a surface with a clear uneven pattern on top of the color shading, so
Compared to conventional two-dimensional coloring methods and embossing, products with a much richer three-dimensional color impression can be obtained, and workability and productivity are also improved. The fibrous substrate used for stamping in the present invention is a fiber aggregate filled with a porous polymer containing a colorant, and is generally a fiber aggregate such as nonwoven fabric, woven fabric, felt, or knitted fabric. It is obtained by an original dyeing method in which the body is impregnated with a polymer solution containing a coloring agent and then the polymer is coagulated. Coagulation methods include a dry method, in which the solvent is removed by heat, etc., and a wet method, in which coagulation is performed in non-solvent vapor or a non-solvent coagulation bath. Since the combination is porous, the three-dimensional color impression after stamping becomes clearer. In the present invention, it is preferable to coagulate the polymer into a fine porous state in a non-solvent coagulation bath because it is possible to increase the difference in K/S value, that is, the range of color difference due to stamping of the fibrous sheet. In cases where the original dyeing method is not used, the fibrous substrate consisting of a fiber aggregate and a polymer may be treated in a coloring agent dissolved or dispersed in an appropriate solvent or dispersion medium before being stamped. It can also be done in a way. The fibers constituting the fiber aggregate include single spun fibers such as staple fiber, rayon, nylon, polyester, polypropylene, polyacrylonitrile, etc., or mixed or composite spun fibers of nylon, polyester, etc. with polystyrene, polyethylene, polypropylene, etc. Ordinary fibers such as irregular cross-section fibers can be used as is. The polymer used in this invention is a polyurethane elastomer. Polyurethane elastomers have a porous structure with pores of various shapes ranging from extremely fine pores to giant pores, which allows the coloring state of the added colorant to be changed. In addition, scratch resistance, abrasion resistance, bending fatigue strength,
It is preferable because there is little change in texture after stamping. Polyurethane elastomer molecular weight
500-4000 polyethylene ether glycol,
Soft segments such as polyhexamethylene ether glycol, polyethylene adipate glycol, polybutylene adipate glycol, polycaprolactone glycol and ethylene glycol,
Chain extenders such as butanediol, ethanolamine, hydrazine, 4,4'-methylenebis(2-chloroaniline) and diphenylmethane-4,4'-
Diisocyanate, tolylene diisocyanate,
Consists of diisocyanates such as hexamethylene diisocyanate. The polyurethane elastomer contains a filler, a softener, a stabilizer, an antistatic agent, a balm conditioner, etc., as well as polymers with good compatibility in a solution state, such as polyvinyl chloride, polyvinyl formal, polymethyl acrylate, and chloride. A copolymer of vinylidene and vinyl acetate or the like may be mixed as necessary. Pigments or dyes can be used as coloring agents, but when producing porous substrates by wet coagulation, inorganic pigments such as carbon black, titanium oxide, barium sulfate, phthalocyanines, anthraquinones, etc. Organic pigments are particularly suitable. The amount of the colorant used is 1% to 300% by weight based on the polymer. If the amount of colorant used is less than 1% by weight, it will be difficult to obtain the desired color by stamping, and if it is more than 300% by weight, the mechanical properties of the porous substrate may deteriorate. The type and amount of colorant used is determined by the desired color after embossing, but in any case, the K/S value before embossing must be low to a certain extent, and in general, porous heavy The K/S value of the surface of the fibrous sheet made of the combined fibers is in the range of 0.5 to 7.0, particularly preferably in the range of 1 to 5. This K/S value
If it is smaller than 0.5, the difference in the desired color shading will be too small even if the porous polymer is strongly pressed at a temperature and pressure sufficient to crush the porous polymer and make it transparent.
Furthermore, if the K/S value is extremely larger than 7, there will be little change in color sense, making it impossible to expect good three-dimensional color sense. The apparent specific gravity of the fibrous base is 0.2 g/cm ³ or more depending on the mechanical properties or the size of color change in the recesses due to embossing.
0.9g/cm ³ is preferable, especially 0.2g/cm ³ to 0.8g/cm ³
is particularly preferred. The above fibrous substrate may further be provided with a non-porous coating layer having a thickness of 100 microns or less. If the thickness of the coating layer is 100 microns or more, not only the texture but also the creasing and bending fatigue strength often deteriorate. The same types of polymers as those for the above-mentioned fibrous substrate can be used for the coating layer, but among them, polyurethane elastomer is the best in terms of physical properties, texture, etc. A coloring agent may be mixed into the polymer within a range that does not inhibit the color change of the recessed portions during subsequent stamping. The coloring agent used in this case is preferably a transparent dye or organic pigment so as not to inhibit the color change of the embossing recesses, but inorganic pigments can also be used as long as they do not significantly impair transparency. For example, the surface of a porous polymer obtained by adding a blue inorganic pigment (ultramarine type) to the polymer contained in a fibrous sheet is pale blue, but this porous polymer is crushed by pressing to create a non-porous When the material becomes transparent, the recesses become a deep ultramarine color, giving a three-dimensional color appearance due to the shading of similar colors. In addition, when a polyurethane solution containing a red organic pigment (alizarin red type) is applied to the surface of the fibrous sheet to form a non-porous coating layer, the surface of the fibrous sheet is pale pink; When the surface is embossed, the recesses become a deep ultramarine color with a hint of purple, giving it a unique appearance. In addition, if a yellow organic pigment (permanent yellow type) is added instead of a red pigment, the convex portions can be yellow and the concave portions can be dark blue-green, resulting in a three-dimensional color feeling and a different color feeling due to the shading. It can be made into a three-dimensional surface. Next, the difference (d ₂ ) between the apparent specific gravity of the concave part (d 2 ) and that of the convex part (d ₁ ) _is
-d ₁ ) is 0.1 or more, and the depth is 80 mm so that the difference (K ₂ -K ₁ ) between the K/S value (K ₂ ) of the concave part and that of the convex part (K ₁ ) is 1.0 or more. Emboss shapes larger than microns. If the difference in apparent specific gravity between the concave and convex portions is less than 0.1, the embossing will not be sharp, making it difficult to express delicately. If the difference (K ₂ - K ₁ ) between the K/S value (K ₂ ) of the embossing depressions and that of the protrusions (K ₁ ) calculated by Kubelker-Munk's formula is less than 1.0, the color difference between the depressions and the protrusions will be If there is too little, the desired three-dimensional color impression cannot be obtained. The depth of embossing is also an important factor that affects the three-dimensional color appearance. The greater the depth, the greater the difference in apparent specific gravity and the difference in K/S value between the concave and convex portions, thereby increasing the three-dimensional color appearance. The embossing depth is required to be at least 80 microns, preferably at least 100 microns, in order to exhibit a great effect on three-dimensional color impression, and the smaller the apparent specific gravity of the porous substrate or the greater the thickness, the greater the depth. It is desirable to do so. In the present invention, it is essential to perform stamping that meets the above three conditions. For example, if the difference in depth between the concave part and the convex part is less than 80 microns, sufficient three-dimensionality cannot be obtained no matter how large the difference in K/S value is selected, and the difference in K/S value is less than 1.0. In this case, even if the difference in depth between the concave portion and the convex portion is increased, a sufficient three-dimensional color impression cannot be obtained. Furthermore, even if the K/S value and the difference in depth are selected within the above ranges, if the embossing is performed under conditions where the difference in specific gravity between concave and convex parts is less than 0.1, the sharpness of the embossing will be poor. Not liked. These preferable conditions include a difference in specific gravity of 0.24 or more, especially 0.3 or more, a difference in depth of 150 microns or more, especially 250 microns or more,
And the difference in K/S value is 1.5 or more, especially 3.0 or more. Either an embossing roll or an embossing plate can be used for the embossing, and the embossing pattern can be arbitrarily selected, such as natural leather-like deep grain or letters. The stamping is performed more strongly than conventional stamping, and the temperature and pressure are selected to be sufficient to collapse the porosity and make it transparent. The conditions in this case vary depending on the desired color difference; if a small color difference is selected, the temperature is low and the pressure is high. On the other hand, if you choose a large color difference, increase the temperature and pressure. Generally, the temperature is 100℃~200℃, the pressure is 1Kg/ ^cm2 ~
500Kg/cm ² and time is selected from the range of 2 seconds to 5 minutes. Note that the above explanation of applying the non-porous coating layer to the fibrous substrate describes the case where it is applied before embossing the fibrous base, but in the present invention, the non-porous coating layer is applied before embossing the fibrous base. A non-porous covering layer can also be applied afterwards. In this case, it is applied to the convex parts of the surface of the base layer after embossing, and it is possible to not only adjust the surface gloss and give a three-dimensional color impression, but also create a three-dimensional appearance with a different color impression, and the effect is The same effect as that obtained before embossing can be obtained. When the non-porous coating layer is a colored layer consisting of a polymer and a colorant, the ratio of the polymer to the colorant is preferably 1 to 3 or less for the former; The thickness of the colored layer is preferably 10 microns or less. If the amount of the coloring agent added is 300% by weight or more based on the polymer, not only the three-dimensional color impression will be impaired, but also the adhesion, bending fatigue strength, etc. will deteriorate. The coloring agent to be added may be a pigment or dye, and dyes or organic pigments with excellent transparency are suitable as the coloring agent because they do not inhibit the color change of the embossed recesses.
Of course, even in this case, inorganic pigments can be used as long as the amount does not significantly impair transparency. If the thickness of the colored layer is 10 microns or more, the bending fatigue strength and surface creasing may deteriorate. As the dye used in the colored layer, any dye soluble in an organic solvent can be used, but metal complex dyes are best from the viewpoint of light resistance, migration properties, coloring properties, etc. The method of applying the colored layer by gravure printing is advantageous in terms of ease of coating on the convex portions and productivity. If other types of embossing patterns than the above-mentioned embossing patterns are required, they can be applied in any step. It is desirable that the embossing is performed under weaker conditions than the aforementioned embossing in order to preserve the embossing pattern. The fibrous sheet obtained as described above has discoloration in the concave portions and different colors in the concave portions and convex portions, giving it a very three-dimensional color appearance and a luxurious feel. The features of the present invention are as follows. (1) Excellent three-dimensional color impression due to the synergistic effect of the three-dimensional effect due to the difference in depth between the concave and convex portions and the three-dimensional effect due to the difference in color difference between the concave and convex portions. (2) Furthermore, the concave parts are darker in color than the convex parts, creating a sense of perspective and doubling the three-dimensional effect. (3) A specific amount of a coloring agent such as a pigment or dye is blended into the impregnated polymer of a leather-like sheet material, which is one of the conventional fibrous polymer sheets, and
A product with a three-dimensional effect can be obtained simply by pressing the sheet more strongly than before, so the resulting sheet naturally retains its leather-like texture. (4) Since the color shading is created using a method called mechanical embossing, the boundaries between the depressions and protrusions of the mold are clear, and the three-dimensional effect at the boundaries is emphasized. (5) When obtaining a fibrous sheet with a three-dimensional color appearance from a fibrous substrate, there is no need to apply a coloring agent, and it is only necessary to mechanically press it, making it easy to produce small quantities and many brands. Therefore, the workability is also good. The present invention will be explained below with reference to specific examples. Note that all percentages in the examples are based on weight. Further, the K/S values in the examples are values measured and calculated using a Shimadzu self-recording spectrophotometer model D-40RC. Example 1 A nonwoven fabric of nylon fibers was impregnated with a solution consisting of 20% polyurethane elastomer synthesized from polyethylene adipate glycol, diphenylmethane-4,4'-diisocyanate, and ethylene glycol, 4% carbon black, 8% dibutyl phthalate, and 68% dimethylformamide. The substrate was immersed in an aqueous solution containing 50% dimethylformamide at 60° C. for 30 minutes to solidify, followed by solvent removal and drying to produce a porous fibrous substrate ( ). The apparent specific gravity of the porous fibrous substrate ( ) was 0.68.
Next, buff this surface with sandpaper,
After reducing the thickness to 1.20 mm, use an embossing roll with a tortoise shell pattern (height 380 microns) at a temperature of 170°C.
Embossing was performed under conditions of a pressure of 35 Kg/cm ² and a time of 32 seconds to produce a fibrous sheet (A). The apparent specific gravity of the wrinkled concave portions of the fibrous sheet (A) was 0.93, that of the convex portions was 0.71, and the difference between the K/S value of the concave portions and that of the convex portions was 4.8. The fibrous sheet (A) has wrinkles with a depth of 261 microns, and the concave portions are greatly discolored, creating a color difference between the concave and convex portions, and is highly heterochromatic and has an extremely rich three-dimensional color feel. It was. When the fibrous sheet (A) was used for bags and interior materials, it gave a very luxurious feel and had high commercial value. Further, on the surface of the fibrous sheet (A) obtained as above, 8% of the same type of polyurethane elastomer as above, 4% of brown azo organic pigment (manufactured by Dainichiseika Kogyo KK), 22% of dimethylformamide, and 28% of acetone. and cyclohexanone
A solution consisting of 38% was applied at a solid content of 2.2g/ ^m2 ,
A fibrous sheet (B) with the desired color was produced. The difference in apparent specific gravity between the wrinkled concave portions and convex portions of this product was almost the same as that of the above-mentioned fibrous sheet (A), but the difference between the K/S value of the concave portions and that of the convex portions was 5.3. Since the color difference was large and the color appearance was rich in three-dimensional color, the fibrous sheet (B) also had high commercial value like the fibrous sheet (A). On the other hand, the same fibrous substrate (2) as above was embossed using an embossing roll with a rhizome pattern (height: 40 microns) under the same conditions as above. The thickness of the convex portions of the obtained fibrous sheet (C) was 1.09 mm and the apparent specific gravity was 0.75, and the thickness of the concave portions was 1.06 mm and the apparent specific gravity was 0.77. The fibrous sheet (C) had wrinkles with a depth of 28 microns, and there was almost no difference in the K/S value between the concave and convex portions.
It lacked a three-dimensional sense of color. On the other hand, a fibrous substrate () was produced in exactly the same manner as above using the same polymer solution as above except that it did not contain carbon black. The apparent specific gravity of the fibrous substrate (2) was approximately the same as that of the above-mentioned fibrous substrate (2). Next, use sandpaper to buff the surface as described above to increase the thickness.
After making it 1.20 mm, it was stamped in the same way as the fibrous sheet (A). The obtained fibrous sheet (D) has almost the same grain depth and convex thickness as the fibrous sheet (A).
Although the grain had a certain thickness and apparent specific gravity, the difference in K/S value between the concave and convex portions of the grain was 0.1, and there was no color difference between the convex and concave portions, and there was no three-dimensional color appearance at all. The above is summarized as follows.

[Table] Example 2 Polyurethane elastomer 8 synthesized from polycaprolactone glycol, 1,4-butanediol, and diphenylmethane-4,4'-diisocyanate on a woven fabric of polyester fiber with naps on one side.
%, polyvinyl chloride 4%, brown pigment (iron oxide/
Yellow lead = 4/1: Dainichiseika Kagyo KK) 0.4%, water 5
% and dimethylacetamide 82.6% and dimethylacetamide 30% at 25 °C.
After treatment with an aqueous solution of for 30 minutes, the solvent was removed and dried to obtain a fibrous sheet with a thickness of 0.82 mm and an apparent specific gravity of 0.31. At the same time, 4% of the same type of polyurethane elastomer as above, 1% of polyvinyl chloride,
Lany Brown3R0.5%, dimethylacetamide 26
A non-porous film was prepared by applying a solution of 38.5% dioxane and 30% acetone to a polyethylene sheet with a solid content of 12 microns. The non-porous film was adhered to the above-mentioned fibrous sheet to obtain a porous fibrous substrate (). Next, the fibrous substrate is stamped using a stamping plate with arbitrary characters and patterns (height 708 microns) engraved using a flat plate press at a temperature of 120°C, a pressure of 30Kg/cm ² , and a time of 20 seconds. did. The thickness of the stamped convex portions of the obtained fibrous sheet (E) is 0.82 mm, the apparent specific gravity is 0.31, and the thickness of the concave portions is 0.26 mm.
The apparent specific gravity was 0.98, and the difference in K/S value between the concave and convex portions was 4.3. The fibrous sheet had dark embossed letters with a depth of 560 microns and was very rich in three-dimensional color. When the fibrous sheet was used for binding albums and books, it gave a very luxurious feel and was well received.

Claims (1)

[Scope of Claims] 1 The inside of the fiber aggregate is filled with a wet-coagulated porous material made of a polymer mainly composed of polyurethane elastomer, and the polymer is further colored with 1 to 300% by weight of the polymer. A fibrous sheet containing an agent and having an apparent specific gravity of 0.2 to 0.9, which has an embossed pattern with a depth of 80 microns or more on the surface of the fibrous sheet with a K/S value of 0.5 to 7.0. Then, the porosity of the polymer mainly composed of polyurethane elastomer in at least _the surface layer of the embossing recesses is crushed, and the difference ( _{d 2}
-d ₁ ) is 0.1 or more, and the difference (K ₂ -K ₁ ) between the K/S value (K ₂ ) of the concave part and the K/S value (K ₁ ) of the convex part is 1.0 or more. Excellent fibrous sheet. 2 The inside of the fiber aggregate is filled with a wet-coagulated porous material made of a polymer mainly composed of polyurethane elastomer, and the polymer further contains a coloring agent of 1 to 300% by weight based on the polymer. A non-porous coating layer of 100 microns or less is formed on the surface of a fibrous sheet with an apparent specific gravity of 0.2 to 0.9, and a non-porous coating layer with a depth of 80 μm is formed on the surface of the fibrous sheet with a K/S value of 0.5 to 7.0. It has an embossed pattern of micron size or larger, and the porosity of the polymer mainly composed of polyurethane elastomer in at least the surface layer of the embossed recesses is crushed, and the apparent specific gravity (d ₂ ) of the recesses and the apparent specific gravity of the convex parts are (d ₁ ), the difference (d ₂ - d ₁ ) is 0.1 or more, and the difference (K ₂ - K ₁ ) between the K/S value (K 2 ) of the concave part and _the K/S value (K ₁ ) of the convex part is 1.0
The above is a fibrous sheet with excellent three-dimensional color appearance. 3 The inside of the fiber aggregate is filled with a wet-coagulated porous material made of a polymer mainly composed of polyurethane elastomer, and the polymer has a ratio of 1% to 1% of the polymer.
A fibrous sheet containing ~300% by weight of a coloring agent, a surface K/S value of 0.5 to 7.0, and an apparent specific gravity of 0.2 to 0.9 is coated with at least a surface layer of a polymer mainly composed of polyurethane elastomer. _The temperature and pressure are sufficient to crush the porosity and make it transparent, and the difference (d 2 ) between the apparent specific gravity of the concave part (d ₂ ) and the apparent specific gravity of the convex part (d ₁ )
−d ₁ ) is 0.1 or more, and the K/S value (K ₂ ) of the concave part
Fiber material with excellent three-dimensional color impression characterized by embossing with a depth of 80 microns or more and a difference (K ₂ - K ₁ ) between the K/S value (K ₁ ) of the convex part and the convex part of 1.0 or more. Seat manufacturing method. 4 The inside of the fiber aggregate is filled with a wet-coagulated porous material made of a polymer mainly composed of polyurethane elastomer, and the polymer has a ratio of 1% to 1% of the polymer.
A non-porous coating layer with a thickness of 100 microns or less is applied to a fibrous sheet containing ~300% by weight of a coloring agent and an apparent specific gravity of 0.2 to 0.9, and the K/S value of the surface is 0.5. ~7.0, at a temperature and pressure sufficient to crush the porosity of the polymer mainly composed of polyurethane elastomer in the surface layer and make it transparent, and the apparent specific gravity of the concave portions (d ₂ ) and the apparent specific gravity of the convex portions ( d ₁ ) is 0.1 or more, and the difference ( _{K 2} - _{K 1} ) between the K/S value (K ₂ ) of the concave part and the K/S value (K ₁ ) of the convex part is _0.1 or more. 1.0
A method for producing a fibrous sheet with excellent three-dimensional color appearance, characterized by performing embossing with a depth of 80 microns or more.