JPH031433B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a leather-like sheet material that has a gloss similar to that of enamel, so-called semi-gloss, has a good crease feel, is soft to the touch, and has excellent bending resistance. In recent years, with the diversification of the appearance of leather materials, not only are there a wide variety of colors, but the surface gloss has also become very diverse, from matte to semi-gloss to enamel. There is. This tendency is also strong in man-made products such as artificial leather, and various improvements have been made to create the appearance.
The surface was rough and it was difficult to improve the gloss using conventional methods. For this purpose, a thick transparent film was attached to the outermost surface of the leather sheet, or a thick layer of transparent resin was applied to improve the luster and create an enamel finish. With this method, it is difficult to control the luster, and only a constant luster, ie, an enamel-like one, can be produced, and the appearance is resinous, giving a cold feeling. In addition, there are almost no wrinkles that occur when folded, resulting in a poor sense of luxury.In terms of physical properties, there is almost no air permeability or moisture permeability, and the bending resistance is also significantly reduced. In order to eliminate these drawbacks, improve gloss, and create a sense of luxury, a widely used method is to apply colored paint to the sheet using a gravure coater, etc., and then coat the surface with clear paint, but the surface of the sheet is rough and cannot be used for the intended purpose. As mentioned above, the desired gloss cannot be obtained. In view of these points, the inventors of the present invention conducted extensive studies and found a method for producing a sheet that eliminates the drawbacks of conventional enamel and has a semi-gloss enamel appearance, which is particularly in high demand from the market, and has thus arrived at the present invention. This is what I did. That is, the present invention provides a leather sheet-like product formed by impregnating and coating a fibrous base material with an elastic polymer.
The apparent density of the coating layer of the leather sheet is 0.45 to 0.58.
g/cm ³ of a microporous layer of polyurethane elastomer (a) an alicyclic diisocyanate (b) a polymer diol having a molecular weight of 600 to 4000 (c) an aliphatic diamine and/or 10% elongation stress obtained from cyclic diamine is 20-150Kg/cm ²
Polyurethane elastomer A (d) Ketones, esters, with a boiling point of 60 to 120°C,
At least 80% by weight of a single or mixed solvent selected from the group consisting of cyclic ethers, alcohols, and hydrocarbon solvents (e) An organic solvent containing 20% by weight or less of an amide solvent with a boiling point of 120°C or higher. A clear paint containing no colored or extender pigments is applied over the entire surface by overfeed spread at least 1 to 20 g/m ² in solid content, and then a 10% elongation stress of 20 to 150 Kg/cm is formed. ² Polyurethane elastomer B
A concealing layer containing a colorant with a solid content of 0.5 to 15
g/ ^m2 is applied to form a second layer, and then the surface is made of polyurethane elastomer C with a 10% elongation stress of 100 to 400 kg/ ^cm2 , and contains only a transparent colorant without an opaque colorant, or is colored. The third layer, which does not contain any additives, is formed by applying a solid content of 0.5 to 10 g/ ^m2.It has a semi-gloss appearance, has fine creases, and has a flexible surface feel. This is a good method for producing leather sheets. First, the leather sheet material constituting the present invention has a structure in which a fibrous base material is impregnated with an elastic polymer and has a microporous coating layer on the surface. The fibrous base material is a fibrous sheet such as nonwoven fabric, woven fabric, or knitted fabric. Natural fibers, synthetic fibers, and recycled fibers can be used as desired. Examples of the elastomeric polymer to be impregnated into the fibrous base material include conventionally known polyurethane, polyurea,
SBR (styrene-butadiene rubber), NBR (acrylonitrile-butadiene rubber), acrylic acid ester polymers, vinyl chloride polymers, etc. can be used. The microporous layer forming the coating layer is preferably a polyurethane elastomer, and a solution or dispersion is applied thereto, and a porous formation method such as a conventionally known technique such as a wet or dry coagulation method, a chemical foaming method, or a mechanical foaming method is applied. to form. In order to achieve the object of the present invention, the apparent density of the coating layer must be in the range of 0.45 to 0.58 g/cm ³ , and if this density is less than 0.45 g/cm ³ , the sheet formed by the method of the present invention The creases on the material become large and the quality deteriorates, which is significantly different from the grains on high-quality leather.On the other hand, when the density exceeds approximately 0.58g/ ^cm2 , the texture becomes hard and it becomes impossible to express fine creases. Become. The density of the porous layer must therefore be between 0.45 and 0.58 g/cm ³ . A polyurethane elastomer [A] is applied to the surface of the sheet-like product thus created. This polyurethane elastomer A consists of (a) an alicyclic diisocyanate, (b) a polymer diol having a molecular weight of 600 to 4,000, and (c) an aliphatic diamine and/or an alicyclic diamine. Here, (a) alicyclic diisocyanates include cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane 4,4' diisocyanate, dicyclohexyldimethylmethane-44' diisocyanate, and (b) polymer diols include polyethylene glycol and polypropylene glycol. , polytetramethylene glycol, polyhexamethylene glycol, etc., polyols, or ester polyols such as polyethylene adipate, polybutylene adipate, etc. can be used alone or in mixtures. Further, (c) aliphatic diamines such as ethylene diamine, 1-2 propylene diamine, hexamethylene diamine, etc., and (c) alicyclic diamines such as piperazine and isophorone diamine 4,4'diaminodicyclohexylmethane, by a known method. It can be obtained by reaction. The reason why alicyclic diisocyanate and aliphatic diamine and/or alicyclic diamine are used in the present invention is that it is necessary to use a soft solvent to dissolve polyurethane. That is, polyurethane using aromatic diisocyanate and aromatic diamine generally cannot be made into a homogeneous solution and is difficult to coat unless a so-called hard solvent, which is mainly an amide solvent, is used as a solvent. However, amide solvents have a high boiling point and a slow evaporation rate, so if a paint containing a large amount of amide solvents is used, it will dissolve the porosity of the coating layer, resulting in a loss of surface smoothness and, as a result, less gloss. As a result, the density of the porous material increases, the material lacks softness, and it becomes difficult to form fine grains, making it impossible to achieve the object of the present invention. Regarding the hardness of the polyurethane used in the present invention, the 10% elongation stress must be in the range of 20 to 150 kg/cm ² , and at approximately 20 kg/cm ² , the physical properties, especially heat resistance, are low and problems such as adhesion occur. Not practical, about 150
If it exceeds Kg/cm ² , the surface becomes hard and the folded grain of the sheet does not become fine and it does not lose its sense of luxury, and physically, the bending durability at low temperatures becomes weak, which causes practical problems. The solvent for dissolving the polyurethane elastomer A of the present invention is a ketone, an ester, a boiling point of 60 to 120°C,
At least 80% by weight of a single or mixed solvent selected from the group consisting of alcohol and hydrocarbon solvents, and 20% by weight of an amide solvent with a boiling point of 120°C or higher.
Use organic solvents mixed in the following proportions. Ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.; esters include ethyl acetate and butyl acetate; cyclic ethers include tetrahydrofuran and furfural; alcohols include ethyl alcohol, n-propyl alcohol, isopropyl alcohol, and carbonized As hydrogen, benzenetoluene, hexane, etc. can be used. As the amide solvent, dimethylformamide, dimethylacetamide, etc. can be used. The mixed solvent system contains 80% by weight or more of a solvent with a boiling point of 60 to 120°C, and these solvents are essential for maintaining the porosity of the coating layer. Approximately 20% by weight of an amide solvent with a boiling point of 120°C or higher is required to form a uniform urethane film. If it exceeds 20% by weight, it will damage the porosity.
It becomes impossible to obtain a sheet-like product with the desired appearance. The polymer solution consisting of the above polyurethane elastomer A and a solvent has a concentration of 5 to 15% by weight and a viscosity of 100%.
It is appropriate to adjust the temperature to ~500 cps/20°C. The thus-prepared paint containing no colored or extender pigment is applied as a first layer to the surface of the sheet by overfeeding at a solid content of 1 to 20 g/m ² . What is overfeed spread coating?
After fixing excess paint to the surface of the sheet material, scrape it off with a doctor blade, rod, etc. to form a uniform paint film, or supply more paint between the nip rolls than the amount picked up on the sheet material and squeeze. This refers to a method in which the adhesive is spread uniformly on the surface of the object to be treated and then squeezed to control the amount of adhesion. The adhesion amount of polyurethane elastomer A coated by this method is 1 to 20 g/ ^m2 , preferably 2 to 10 g/ ^m2 , and if it is ^less than about 1 g/m2, a uniform film cannot be formed. However, it causes glossy spots and is a drawback, and it is necessary to apply it once, or at most 2 to 3 times, in order to form a uniform film and create a glossy finish. On the other hand, if it exceeds about 20 g/m ² , the amount of coating per coat increases, which tends to be affected by the solvent, and properties such as air permeability and moisture permeability are greatly reduced, which is undesirable. Further, it is necessary that the paint does not contain coloring or extender pigments. Containing pigment deteriorates the surface roughness and makes it impossible to increase the gloss level. In short, the first layer coating must form a smooth film without roughening the porous surface. Next, it is made of polyurethane elastomer B with a 10% elongation stress of 20 to 150 kg/cm ² and a coloring agent of 3 to 30 kg/cm 2 is added.
Concealing layer containing 200% by weight, solid content 0.5-15g/m ² ,
Preferably 1 to 10 g/m ² is applied. The polyurethane elastomer used here may be the lift sorbate type mentioned above, or a hard sorbate type using aromatic diisocyanate. The amount of colorant is from 3 to 200 weight percent, preferably from 5 to 150 weight percent based on the polyurethane elastomer.
It is a percentage. If the amount of the colorant is less than about 3% by weight, the covering layer has poor hiding properties and color spots occur. On the other hand, if it exceeds about 200% by weight, the mechanical properties of the sheet material, especially the bending durability, deteriorate, so it cannot be used. The coating amount of the paint needs to be in the range of 0.5 to 15 g/m ² , preferably 1 to 8 g/m ² . If the coating amount is less than about 0.5 g/ ^m2 , uniform coloring will not be possible and color spots will occur, whereas if it exceeds about 15 g/ ^m2 , it will be difficult to create minute creases and the surface will become softer. As a result, air permeability and moisture permeability are significantly lowered, which is undesirable. Next, a 10% elongation stress was applied to the surface on which the hidden layer was created.
0.5 as the third layer of polyurethane elastomer C with a weight of 100 to 400 Kg/ ^cm2 , containing no opaque colorant, only a transparent colorant, or no colorant at all.
Apply ~10g/ ^m2 . The hardness of polyurethane is 10% elongation stress is 100 to 400
Kg/cm ² , preferably 150 to 380 Kg/cm ² . If it is less than about 100 Kg/cm ² , the surface will be highly sticky, causing problems in practice, and the appearance will be broken. The appearance of grain is extremely poor and the product does not have a high-class feel. On the other hand, if it exceeds about 400 Kg/cm ² , it will not be able to develop many minute folded grains, resulting in coarse grains and a loss of luxury, as well as a marked decrease in bending durability, resulting in no practical strength. The 10% elongation stress of polyurethane C is 150 to 380 Kg/
^cm2 is required. Further, when a transparent colorant is included, a metal-containing complex salt dye or the like which is soluble in an organic solvent can be used as the colorant.
The amount of coloring agent is adjusted appropriately depending on the depth of color, but is usually 5 to 100% by weight. If the coating amount is less than about 0.5 g/m ² , it is impossible to obtain a semi-gloss high-quality gloss, while if it exceeds about 10 g/m ² , the bending durability of the surface will decrease and at the same time the appearance will be semi-gloss. It goes beyond its luxurious luster to become enamel-like and loses its luxurious feel. Preferably it is 1 to 5 g/m ² . The leather sheet obtained in this manner does not have a glittering luster like enamel, but has a calm glossy surface appearance, extremely delicate folding grains, and a soft surface feel. The present invention will be specifically explained below using Examples.
The various physical properties shown in the examples were measured in the following manner. Furthermore, Table 1 shows the physical properties of the sheet-like products prepared in Examples and Comparative Examples, and Table 2 shows the main specifications constituting the sheets. 10% elongation stress of polyurethane elastomer According to JISK-6301-3 vulcanized rubber tensile test method,
After making a size 2 dumbbell and storing it at 20±2℃ for 24 hours, the tensile speed was measured using an Instron type tensile tester.
Measured at 200mm/mm. Bending resistance A bending test of 200,000 times was conducted according to the leather bending test method of JISK-6545. And JIS-K-6505
Judgment was made in accordance with 5.2. The larger the value, the better the bending resistance. Low-temperature flexibility is the value obtained when the film is bent 100,000 times at -10°C using the method described above. Moisture permeability Measured according to the method of JIS-K-6505-5-2-13. Example 1 [Manufacture of fibrous base material] Polyethylene terephthalate fibers (single fiber fineness 2.5 denier, length 51 mm) with a shrinkage rate of 45% in hot water at 70°C were used to reduce the weight using a flat card.
A web of 200 g/m ² was produced. This web was passed through a needle rocker room and needle punched at 800 needles/cm ² , and then immersed in warm water at 68° C. for 5 minutes to shrink to 62% of its original area. This shrink web is 0.10Kg/0.10Kg using a belt press dryer.
Dry at 130℃ under a pressure of cm ² and weigh 290℃.
A nonwoven fabric (fibrous base material) having a weight of 1.1 mm and an apparent density of 0.26 g/m ² was obtained ^. [Production of polyurethane elastomer] 585 parts of polybutylene adipate (molecular weight
1709), 311 parts of polytetramethylene ether glycol (molecular weight 1493), 126 parts of 2,2-bis[4
A mixture of -(β-hydroxyethoxy)phenyl]propane, 670 parts of diphenylmethane-4,4'-diisocyanate, 0.05 parts of triethylenediamine (catalyst) and 411 parts of methyl ethyl ketone (solvent) was heated in a stirred reactor for 50 minutes. The reaction was carried out at ℃ for 80 minutes to obtain a polyurethane prepolymer. 156 parts of 1,4-
Butanediol and 3.2 parts of triethylenediamine (catalyst) were added, and while 6789 parts of methyl ethyl ketone was gradually added dropwise, the reaction was carried out at 80°C for 4 hours. The polyurethane elastomer thus obtained was in the form of a slurry and had a concentration of 20% by weight. [Manufacture of leather sheet having a porous coating layer] 1.0% by weight of a polyethylene oxide surfactant was added to the polyurethane slurry-like elastomer obtained as described above, and while stirring with a homomixer, 28% by weight per 100 parts of the slurry was added. Add part of water,
An organic solvent slurry of a polyurethane composition containing water was obtained. The nonwoven fabric obtained as described above was immersed in the slurry thus obtained, and then squeezed with a squeeze roll to a pick-up of 440% by weight to obtain an impregnated nonwoven fabric impregnated with 1270 g/m ² of the slurry. One side of this impregnated nonwoven fabric was coated with the same slurry as above using a knife coater to a weight of 750 g/m ² to form a coating layer.
The obtained polyurethane fabric was immersed in water at 30°C for 5 minutes to partially gel the polyurethane composition, and then soaked at a temperature of 40°C.
The sample was dried for 30 minutes in a humid atmosphere at 70% RH to evaporate methyl ethyletone. Next, it was dried at 110°C for 15 minutes to completely evaporate and remove water. The weight of the leather sheet thus obtained was 615
g/m ² , thickness 1.4 mm, and the apparent density of the coating layer is
It was 0.46g/ ^cm3 . [Synthesis of polyurethane elastomer A] Polytetramethylene glycol with a molecular weight of 2820
751.8 parts of dicyclohexylmethane diisocyanate and 209.5 parts of dicyclohexylmethane diisocyanate were placed in a stirred reactor purged with nitrogen.
After reacting at 90°C for 80 minutes, 3845.2 parts of a solvent mixed in a ratio of 5/4/1 of methyl ethyl ketone/tetrahydrofuran/dimethylformamide was added and cooled to 40°C while dissolving to obtain a 20% by weight liquid. Next, a solution of 38.7 parts of 1,2-propylene diamine dissolved in 154.8 parts of the same mixed solvent was added little by little to carry out a chain elongation reaction. After reacting for 8 hours, 3.5 parts of dibutylamine was added to stop the reaction, and the mixture was heated at 30°C.
A solution of 1200 poise was obtained. The resulting polymer was diluted to 10% by weight with dimethylformamide, poured onto a glass plate with a stylus, roughly dried at 50°C for about 12 hours, and then vacuum-dried at 80°C for 2 hours to produce a transparent polyurethane film. This film was heated at 20℃.
×10 Measured after controlling the humidity indoors at 60% RH for one day
The % elongation stress was 25 Kg/cm ² and the intrinsic viscosity measured in dimethylformamide at 30° C. was 1.02. [Synthesis of polyurethane elastomer B] Polytetramethylene glycol with a molecular weight of 2012
597.5 parts diphenylmethane diisocyanate
Pour 297.0 parts into a stirred reactor purged with nitrogen at 70°C.
After reacting for 60 minutes, methyl ethyl ketone/
3578 parts of a mixed solvent of dimethylformamide = 5/5 was added and dissolved while cooling to obtain a 20% by weight liquid.
Next, 0.2 parts of digtyltine dilaurate was added, and 90.1 parts of 1,4-butanediol was dissolved in 360 parts of the same mixed solvent as above, and the solution was poured for 1 hour, followed by a reaction for 6 hours, and 3.5 parts of dibutylamine was added to stop the reaction. The obtained polymer solution had a temperature of 1050 poise at 30°C, a 10% elongation stress of 40 Kg/cm ² and an intrinsic viscosity of 0.90, as measured by the same method as above. [Synthesis of polyurethane elastomer C] Polytetramethylene glycol with a molecular weight of 1580
6142 parts of 3,3,5 trimethyl, 5 isocyanate and 257.7 parts of methyl cyclohexyl isocyanate were placed in a reactor equipped with a stirrer purged with nitrogen and reacted at 90°C for 80 minutes, followed by methyl ethyl ketone/tetrahydrofuran/dimethylformamide = 2/4/
Add 3488 parts of the mixed solvent from step 4 and dissolve while cooling.
Cooled to 40°C. Then 3,3,5 trimethyl,5 aminomethylcyclohexylamine 128.1
A solution of 512 parts of the above-mentioned mixed solvent was added thereto, and a chain elongation reaction was carried out at 40 to 50°C for 8 hours.Finally, 3.5 parts of di-n-butylamine was added to stop the reaction. The obtained polymer solution had a temperature of 980 poise at 30°C, an intrinsic viscosity of 0.85, and a 10% elongation stress of 150 Kg/cm ² . [Manufacture of leather sheet] Polyurethane elastomer A is applied to the surface of the sheet having the porous coating layer obtained as described above using isopropyl alcohol/methyl ethyl ketone/
It was diluted to 10% by weight with a solvent mixed with dimethylformamide = 5/4/1 to prepare a clear paint of 200 centipoise at 20°C. 3g/ solid content of this
Using a gravure roll with a line count of 150 lines/ ^inch so that the width is 150 lines/inch, and without using a doctor blade, overfeed the paint so that the excess paint adheres to the surface of the sheet, and then squeeze it off with a nip roll and spread it over the entire surface. A uniform coating was formed on the surface. Then, using polyurethane elastomer B, a colored black pigment was added as shown in the following composition using a mixed solvent of tetrahydrofuran/methyl ethyl ketone/dimethyl formamide = 5/4/1 to prepare a paint having a density of 150 centipoise at 20°C. UST2790 Black: 70g (Nissei Ka) Polyurethane B: 150g Teilahydrofuran/: 230g Methyl Ethyl Ketone/Dimethylformamide = 5/4/1 Using this paint, apply 110g to the surface of the sheet.
A sheet with a uniformly colored surface was obtained by depositing 3.0 g/m ² with a line/inch gravure roll. Next, a clear paint was prepared by diluting polyurethane C to 10% by weight with a mixed solvent of isopropyl alcohol/toluene/methyl ethyl ketone/dimethyl formamide = 3/3/3/1, and a coating method of 2.0 g/m was applied in the same manner as the colored paint. ² coated. The leather sheet product thus obtained had an extremely glossy appearance, delicate creases, and a very soft surface feel. Table 1 shows data on appearance and physical properties. Example 2 [Manufacture of a leather-like sheet having a porous coating layer] Use the sheet prepared in Example 1 as is [Manufacture of polyurethane A] Use the polyurethane of Example 1 [Manufacture of polyurethane B] Polyurethane of Example 1 [Manufacture of polyurethane C] Polytetramethylene glycol with a molecular weight of 801
446.3 parts and 3,3,5 trimethyl,5 isocyanate methylcyclohexyl isocyanate 369.9
Place the sample in a reactor with a stirrer purged with nitrogen and heat at 90℃ for 80 minutes.
After reacting for a minute, methyl ethyl ketone/tetrahydrofuran/dimethylformamide=2/
Add 3265 parts of a 4/4 mixed solvent and dissolve while cooling, cool to 40°C, then add 183.8 parts of 3,3,5 trimethyl 5-aminomethyl cyclohexylamine dissolved in 735 parts of the above mixed solvent, 40
The chain extension reaction was carried out at ~50°C for 8 hours, and finally the di-n
- 3.5 parts of butylamine was added to stop the reaction. The obtained polymer solution had a temperature of 980 poise at 30°C, an intrinsic viscosity of 0.85, and a 10% elongation stress of 340 Kg/cm ² . [Manufacture of leather sheet] The surface of the sheet having the porous coating layer obtained as described above was coated with polyurethane elastomer A in the same manner as in Example 1, and a sheet having a diameter of 200 centipoise was prepared at 20°C. . The solid content of this is 7
A uniform film was prepared by rod coating using a rod wound with 10 mil stainless steel wire so as to give a coating weight of 10 g/m ² . Next, polyurethane elastomer B was made into a colored paint in exactly the same manner as in Example 1, and it was coated with a gravure roll of 110 lines/inch at 7.0 g/m ^{2 .}
It was attached. Furthermore, the polyurethane elastomer C prepared as described above was diluted 10% with a mixed solvent of isopropyl alcohol/toluene/methyl ethyl ketone/dimethyl formamide = 3/3/3/1.
A leather-like sheet material was prepared by diluting the solution to 4.0 g/m ² with a gluvia roll. The sheet material thus produced was extremely glossy, had delicate creases similar to those in Example 1, and had a soft surface feel. The main properties are shown in Table 1. Comparative Example 1 [Manufacture of fibrous base material] Use the material of Example 1 [Manufacture of polyurethane elastomer] Use the material of Example 1 [Manufacture of leather-like sheet having a porous coating layer] Created in Example 1 Using a polyurethane slurry-like elastomer, 32 parts of water was added to 100 parts of the slurry in the same manner as in Example 1, and the mixture was stirred with a homomixer to obtain an organic solvent slurry of polyurethane. Using this, a leather-like sheet having a porous coating layer was produced according to the method described in Example 1. The sheet thus obtained weighs 600 g/m ² and has a thickness of
1.37 mm, and the apparent density of the coating layer was 0.40 g/cm ³ . When a colored sheet was prepared using this sheet in exactly the same manner as in Example 1, the surface gloss was almost the same as that in Example 1, but there were folds and wrinkles due to the low density of the porous material. It was coarse and did not look good. Also, the low temperature resistance was not good. Comparative Example 2 [Manufacture of fibrous base material] Use the material of Example 1 [Manufacture of polyurethane elastomer] Use the material manufactured in Example 1 [Manufacture of leather-like sheet having a porous coating layer] In Example 1 Using the prepared polyurethane slurry-like elastomer, 20 parts of water was added to 100 parts of the slurry in the same manner as in Example 1, and the mixture was stirred with a homomixer to obtain an organic solvent slurry of polyurethane. Using this, a leather-like sheet having a porous coating layer was obtained in the same manner as described in Example 1. The sheet thus obtained weighs 590 g/m ² and has a thickness of 1.36
mm, and the apparent density of the coating layer was 0.60 g/cm ³ . When a colored sheet was prepared using this sheet in exactly the same manner as in Example 1, the surface gloss was almost the same as that in Example 1, but it had a cold, resin-like appearance with almost no creases. It was a leather-like seat with no soft feel. In addition, the moisture permeability was significantly lower than that of the present invention. Example 3 [Manufacture of a leather-like sheet having a porous coating layer] Using the same fibrous base material as created in Example 1,
The same leather-like sheet was produced using the same polyurethane elastomer slurry as in Example 1 under the same conditions. [Production of polyurethane elastomer A] 701 parts of polybutylene adipate with a molecular weight of 3250,
After 190.9 parts of isophorone diisocyanate was placed in a stirred reactor purged with nitrogen and reacted at 90°C for 80 minutes, a solvent was prepared by mixing methyl ethyl ketone/toluene/dimethylformacide in the ratio of 4/4/2.
3567.6 parts were added and cooled to 40°C while dissolving to obtain a 20% by weight solution. Next, 107.3 parts of isophoronediamine dissolved in 429.2 parts of the same mixed solvent was added little by little.
After carrying out a chain extension reaction and reacting for 8 hours, 3.5 parts of dibutylamine was added to stop the reaction, and the reaction was heated at 30℃ for 200 hours.
A solution of poise was obtained. A film was made from the obtained polymer by the method described in Example 1, and the measured 10% elongation stress was
It was 130Kg/ ^cm2 . [Synthesis of polyurethane elastomer B] Polytetramethylene glycol with a molecular weight of 2012
583.6 parts, diphenylmethane diisocyanate
70 Pour 326.3 parts into a reactor with a stirrer and replace with nitrogen.
After reacting at ℃ for 60 minutes, methyl ethyl ketone/
3,640 parts of a mixed solvent of dimethylformacide = 5/5 was added and dissolved while cooling to obtain a 20% by weight liquid. Next, 0.2 parts of dibutyltin dilaurate was added, and then 90.1 parts of 1,4-butanediol was dissolved in 360 parts of the same mixed solvent as above and poured over 1 hour. The mixture was allowed to react for 6 hours, and 3.5 parts of dibutylamine was added to stop the reaction. Ta. The obtained polymer was heated to 800 °C at 30 °C.
Poise, intrinsic viscosity 0.90, 10% elongation stress 130Kg/
It was warm in ^cm2 . [Manufacture of leather sheet] The polyurethane elastomer A is applied to the surface of the leather sheet having the porous coating layer obtained as described above, and isopropyl alcohol/toluene/
Methyl ethyl ketone/dimethylformamide =
It was diluted to 10.5% by weight with a solvent mixed in 3/3/3/1 to prepare a clear paint with a 250 centipoise temperature at 20°C. This was applied by the method of Example 1 at a concentration of 3 g/m ² to form a uniform coating film. Next, using polyurethane elastomer B, a colored pigment was added in the following composition using a mixed solvent of tetrahydrofuran/dioxane/dimethylformamide = 5/4/1 to prepare a paint having a strength of 150 centipoise at 20°C. UST2692 Blue 100g Polyurethane B 150g Tetrahydrofuran/Dioxane/Dimethylformamide = 5/4/1 200g Using this paint, the surface of the sheet was 110 lines/
A sheet with a uniformly colored surface was obtained by applying a solid content of 7 g/m ² using an inch gravure roll. Next, the polyurethane elastomer C used in Example 1 was applied in the same manner as the polyurethane elastomer B so that the amount was 4 g/m ² . The sheet thus obtained had the extremely deep luster of a semi-gloss enamel, and had a soft feel with delicate creases similar to those of Example 1. The main properties are shown in Table 1. Example 4 Polyurethane elastomer C in Example 3
Instead, the 10% elongation stress used in Example 2 is 340
Kg/cm ² was used. The other materials used were the same as in Example 3. Example 2 shows how to apply polyurethane A, B, and C.
In the same manner as above, 7 g/m ² of polyurethane A, 3 g/m ² of polyurethane B, and 2 g/m ² of polyurethane C were applied. The resulting leather-like sheet was substantially the same as that of Example 2, and had a semi-gloss luster and very fine creases. The main properties are shown in Table 1. Comparative Example 3 [Manufacture of polyurethane elastomer A] Polytetramethylene glycol with a molecular weight of 2900
757 parts of dicyclohexylmethane diisocyanate and 205.2 parts of dicyclohexylmethane diisocyanate were placed in a stirred reactor purged with nitrogen.
After reacting at ℃ for 80 minutes, 3848 parts of a solvent mixed at a ratio of 5/4/1 of methyl ethyl ketone/tetrahydrofuran/dimethylformamide was added and dissolved while cooling to 40 ℃ to form a 20% by weight liquid. . Next, a solution of 37.9 parts of 1,2-propylene diamine dissolved in 152 parts of the same mixed solvent was added little by little to carry out a chain extension reaction. After reacting for 8 hours, 3.5 parts of dibutylamine was added to stop the reaction, and the mixture was heated at 30°C.
A solution of 650 poise was obtained. 10% of the film measured using this polymer by the measuring method shown in Example 1.
The elongation stress was 15Kg/ ^cm2 . [Manufacture of leather sheet] A sheet was manufactured using the same material as in Example 1 except for polyurethane elastomer A, and in the same manner as in Example 1, but after applying polyurethane A,
Even when the solvent is dried, the surface does not have sufficient smoothness, and before applying polyurethane elastomer B, a part of the surface sticks to the guide roll, etc., causing glossy spots, resulting in a uniform semi-gloss appearance that is suitable for practical use. I couldn't help it. In addition, there were almost no creases and the sheet did not have the soft feel of vinyl leather. Comparative Example 4 Polyurethane elastomer A in Comparative Example 3
A second layer was formed by substituting polyurethane elastomer B. A leather-like sheet was prepared using the same other materials as in Example 1, but as in Comparative Example 3, a sheet with a uniform semi-gloss appearance could not be obtained. Furthermore, the folded grain was also poor as in Comparative Example 3, and the quality was poor. The surface texture felt mottled, which was thought to be due to the mottling of the gloss. Comparative Example 5 [Manufacture of polyurethane elastomer A] Polytetramethylene glycol with a molecular weight of 1580
614.2 parts of isophorone diisocyanate and 257.7 parts of isophorone diisocyanate were placed in a stirred reactor purged with nitrogen, and reacted at 90°C for 80 minutes, then methyl ethyl ketone/tetrahydrofuran/dimethylformamide = 5/4/
3487.6 parts of a solvent mixed at a ratio of 1:1 was added and dissolved while cooling to 40°C to form a 20% liquid. Next, a solution of 128.1 parts of isophorone diamine dissolved in 514.2 parts of the same mixed solvent was added little by little to carry out a chain extension reaction. After reacting for 8 hours, 3.5 parts of dibutylamine was added to stop the reaction, and a A solution was obtained. The 10% elongation stress of the obtained polymer is 180
It was Kg/ ^cm2 . [Production of Leather Sheet] A leather sheet was produced by the method of Example 1 using the polyurethane elastomer A obtained as described above. The fibrous base material and polyurethane B and polyurethane C were the same as in Example 1, respectively.
The conditions were also the same. The appearance of the sheet made in this way is Example 1
It had a semi-glossy luster, giving it a luxurious feel, but the grain when folded was rough and lacked a luxurious feel. This occurred because the 10% elongation stress of polyurethane elastomer A forming the first layer was too high. Regarding other physical properties, the bending resistance was inferior to Examples 1 to 4. Example 5 [Fibrous base material] The same material as in Example 1 was used [Production of leather-like sheet with porous coating layer] 1.0% by weight of polyethylene oxide surfactant was added to the polyurethane slurry-like elastomer prepared in Example 1. was added, and 23 parts of water was added per 100 parts of the slurry while stirring with a homomixer to obtain an organic solvent slurry of a polyurethane composition containing water. The fibrous base material is immersed in the slurry thus obtained, and then squeezed with a squeeze roll to a pick-up of 440% by weight to obtain a slurry.
An impregnated nonwoven fabric impregnated with 1270 g/m ² was obtained. One side of this impregnated nonwoven fabric was coated with the same slurry as above at 750 g/m ² using a knife coater to form a coating layer. The obtained sheet was immersed in warm water at 30°C for 5 minutes to partially gel the polyurethane composition, and then
30 in a humid atmosphere with a temperature of 40℃ and a relative humidity of 70%RH.
The mixture was dried for a minute to evaporate the methyl ethyl ketone.
Next, it was dried at 110°C for 15 minutes to remove water by evaporation. The weight of the leather-like sheet thus obtained is 620
g/m ² , thickness was 1.35 mm, and the apparent density of the coating layer was 0.56 g/cm ³ . [Manufacture of leather sheet-like product] Example 1 was added to the sheet manufactured as described above.
Using polyurethane elastomer A with a 10% elongation stress of 25 Kg/cm ² used in Example 1, using methyl ethyl ketone/ethyl acetate/n-propyl alcohol/hexane/DMF=2/2/2/2/2 as the diluting solvent. It was applied twice using the method described above to achieve a solid content of 7 g/m ² . Next, 10 used in Example 3
Polyurethane elastomer B with a % elongation stress of 130 Kg/cm ² was adhered at 3.0 g/m ² by gravure method, and the same 10% elongation stress used in Example 3 was 150 Kg/cm ²
A sheet was prepared by adding 5% by weight of silicon oxide for matting to a polyurethane elastomer and adhering it to a solid content of 4.0 g/m ² . The sheet thus produced had a semi-gloss luster, but had a subdued luster due to the silicon oxide. The bending grain and bending resistance were also approximately the same as those of Examples 1 to 4 and were excellent. Example 6 Apparent density of porous coating layer used in Example 5
Using a sheet of 0.56g/ ^cm3 , polyurethane A and B
Similarly to Example 5, those having 10% elongation stress of 25 Kg/cm ² and 130 Kg/cm ² were used, respectively. Polyurethane A was applied once by the method of Example 1 to give a solid content of 3 g/m ² . Polyurethane B was coated with a solid content of 7 g/m ² in the same manner as in Example 3. Polyurethane elastomer C was used in Examples 2 and 4.
Using the same material with a 10% elongation stress of 350 Kg/cm ² , a solid content of 2.0 g/m ² was attached using the gravure method. The leather-like sheet made in this way has a high-quality semi-gloss luster, has very delicate folding grains as in Examples 1 to 6, and has physical properties such as bending resistance as shown in Table 1. It was good and warm. Comparative Example 6 The 10% elongation stress created in Comparative Example 5 is 180Kg/cm ²
Polyurethane A was used in place of polyurethane B, and a solids content of 5 g/cm ² was applied. As polyurethane A, the 10% elongation stress used in Example 1 was 25
Kg/cm ² was used, and 3g/cm 2 was used in the method of Example 1.
^m2 applied. Polyurethane C has a 10% elongation stress.
150Kg/cm ² was gravure coated at 5g/m ² . As with Comparative Example 5, the sheets produced in this manner had rough folds and wrinkles due to the hard resin applied to the second layer, poor appearance quality, and inferior bending resistance compared to Example 6. Ta. Example 7 Using the same sheet as used in Example 5 with an apparent density of 0.56 g/cm ³ for each porous coating layer, polyurethane A
The same 10% elongation stress as in Examples 3 and 4 is 130Kg/cm ²
7 g/m ² in the same manner as in Example 5 using
of solid content was applied. Polyurethane B was the same as that used in Examples 1 and 2 and had a 10% elongation stress of 25 Kg/cm ² , and was coated with a solid content of 7 g/m ² as in Examples 2 and 3. The polyurethane C prepared in Example 1 with a 10% elongation stress of 150 Kg/cm ² was used, and 2
A semi-gloss sheet was prepared by applying a solid content of g/m ² . The sheets thus produced had a deep luster similar to those produced in Examples 1 to 6, had very fine creases, and had excellent bending resistance. Comparative Example 7 Instead of polyurethane C in Example 7, polyurethane A in Example 3 with a slightly different composition and a 10% elongation stress of 60 Kg/cm ² was applied at 5 g/m ² to form a sheet. When produced, the sheet had a vinyl-like appearance without the delicate creases that are an effect of the present invention and with insufficient gloss. This is because the hardness of the third layer of polyurethane C was insufficient compared to that of the present invention. Example 8 The porous coating layer used in Examples 5 to 7 had an apparent density of 0.56 g/cm ³ , and polyurethane A was the one prepared in Example 3 with a 10% elongation stress of 130 Kg/cm ² . As in Example 3, a solid content of 3 g/m ² was applied. Polyurethane B used in Examples 1 and 2 and having a 10% elongation stress of 25 kg/cm ² was applied at 3.0 g/m ² by the method of Example 1. Polyurethane C has a 10% elongation stress of 350 Kg/cm ² as in Example 2, and the stress is 4.0 as in Example 2.
A solids content of g/cm ² was applied. The sheet thus produced had a semi-gloss, high-quality gloss, and had excellent bending resistance with delicate folded grain. Comparative Example 8 In place of polyurethane C in Example 8, a product was prepared in substantially the same manner as in Example 2.
A material with a 10% elongation stress of 420 kg/cm ² was used and applied by a 4 g/m ² gravure method. Although this sheet had a semi-glossy gloss, the creases were coarse and the leather texture was poor. Also, the bending resistance was poor. Comparative Example 9 The first layer of polyurethane A used in Example 1 was
A clear paint of 200 centipoise was prepared by diluting it with DMF at 20°C, and was applied by the method of Example 1. Second
The third layer was the same as in Example 1. The thus-produced sheet had a large amount of DMF in the first layer, which damaged the porous polymer, resulting in a lack of luster, almost no creases, and significantly reduced moisture permeability. The bending resistance was also inferior to other examples. Comparative Example 10 Using the same material according to the method of Example 1, the first
1 g/m ² of polyurethane A in the layer, 0.5 g/m ² of polyurethane B in the second layer, and polyurethane C in the third layer.
When a sheet was prepared by applying 0.5 g/m ² of the same, the amount of coating was insufficient in each layer, so the gloss described in the present invention could not be obtained, and the creases were also insufficient.

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Claims (1)

[Scope of Claims] 1. A leather sheet formed by impregnating and coating a fibrous base material with an elastic polymer, wherein the apparent density of the coating layer of the leather sheet is 0.45 to 0.58 g/cm. ^A ) (a) alicyclic diisocyanate,
(b) Polymer diol with a molecular weight of 600 to 4000, (c) Polyurethane elastomer [A] with a 10% elongation stress of 20 to 150 Kg/cm ² obtained from aliphatic diamine and/or alicyclic diamine, b) Boiling point At least 80% by weight of a single or mixed solvent selected from the group consisting of ketones, esters, cyclic ethers, alcohols and hydrocarbon solvents at a temperature of 60 to 120°C and a boiling point of 120°C
A clear paint containing no colored or extender pigments, consisting of an organic solvent mixed with the above amide solvents in a proportion of 20% by weight or less, with a solid content of at least 1 to 20%.
g/m ² over the entire surface to form the first layer, and then the 10% elongation stress is 20 to 150 kg/m2.
Composed of polyurethane elastomer [B] of cm ² ,
A second layer is formed by applying a concealing layer containing a colorant at a solid content of 0.5 to 15 g/m ² , and then an opaque layer made of polyurethane elastomer [C] with a 10% elongation stress of 100 to 400 Kg/cm ² is applied to the surface of the second layer. Good flexibility with a semi-gloss texture and crease texture, characterized by forming a third layer that does not contain a coloring agent and only contains a transparent coloring or no coloring agent at a solid content of 0.5 to 10 g/m ² A method for manufacturing leather sheets.