JPS6237153B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to artificial leather having excellent moisture permeability and weather resistance. Artificial leather is used as an alternative material to natural leather for shoes, clothing,
It has come to be widely used in bags, exercise equipment, etc. However, although the quality of conventional artificial leather has surpassed that of natural leather in terms of strength and durability, it is still of insufficient quality in terms of the so-called "stuffy" feeling, especially when used in shoes. is not obtained. In order to improve this "stuffy" feeling, it is necessary to provide shoes with high moisture permeability, but it is extremely advantageous to have shoes that have the wear durability and weather resistance required of shoes, as well as high moisture permeability. It hasn't been done yet. Conventionally, in order to impart moisture permeability to artificial leather, a nonwoven fabric is used as a base fabric, and a continuous porous layer of resin such as polyurethane resin is formed thereon. This has made it possible to bring the moisture permeability to a level that is quite close to that of natural leather, but on the other hand, there are problems such as the product-like appearance and the infiltration of rainwater from the surface.
In order to eliminate this problem, finishing paint is applied to the surface, but this significantly reduces moisture permeability, so various finishing paints have been developed to prevent this reduction. Ta. Examples of resins used as this finishing paint include hydrophilic acrylic resins, cellulose resins, polyalumide resins, and polyurethane resins.
Polyurethane resins are most preferred from the viewpoint of comprehensive properties such as blocking resistance, weather resistance, crack resistance, and low temperature bending resistance. As a method of improving moisture permeability, the use of a polyether urethane resin having a polyoxyethylene chain as a soft segment as a finishing paint was developed (Japanese Patent Publication No. 54-961). However, when the content of polyoxyethylene chains in the polyether-based urethane resin increases, there are problems in that the photodeterioration caused by sunlight etc. increases, cracks are likely to occur, and discoloration is severe. In order to solve this problem, the present inventor conducted further research and found that as a surface finishing coating for the artificial leather substrate, (1) an organic diisocyanate (2) a low molecular chain extender with a molecular weight of 400 or less (3) a molecular weight The polyalkylene oxide glycol consisting of an alkylene oxide having 900 to 3,500 carbon atoms contains at least one cyclic group of the unit shown below in the molecular chain, and the polyalkylene oxide component is a polyoxyethylene chain. Polyurethane resin consisting of polydiol containing 50% or more of components based on In the formula, R ₁ and R ₂ represent a C ₁ -C ₃ alkyl group or hydrogen, and X represents hydrogen, Cl or Br. It has been found that when using this method, photodeterioration caused by sunlight, cracking, and discoloration such as yellowing can be significantly improved, and a product with high moisture permeability can be obtained. The present invention was completed based on this knowledge. The polydiol containing a cyclic group used in the present invention can be obtained by subjecting a bisphenol derivative or a hydrogenated bisphenol derivative to a ring-opening addition reaction with ethylene oxide, propylene oxide, or butylene oxide. In this case, in order to obtain high moisture permeability, it is preferable to add ethylene oxide. However, alkylene oxide having up to 4 carbon atoms such as propylene oxide may be mixed and added within a range of less than 50%. 50% of these polyalkylene oxides
If the above-mentioned amounts are mixed and added, the moisture permeability will decrease. The polyurethane resin for finishing paint used in the present invention needs to have the required hardness (modulus), concentration, and viscosity of the paint film suitable for coating work, and therefore, it is necessary to adjust the degree of polymerization, etc. It is. Therefore, the molecular weight of the polymer diol containing a cyclic group used in the present invention needs to be in the range of 900 to 3,500, preferably in the range of 1,500 to 2,800. If the molecular weight is less than 900, fewer polyethylene oxide segments are included in the chain of the polymer diol, resulting in increased rigidity of the soft segment, higher modulus at low temperatures, and lower low-temperature bending resistance and moisture permeability. When the molecular weight is greater than 3500, the proportion of bisphenol groups in the polymer diol chain decreases, and the polyethylene oxide segment component increases, resulting in deterioration due to light and discoloration such as yellowing. The proportion of the cyclic group is preferably such that the ratio of the molecular weight of the polyalkylene ether portion excluding the cyclic group to the molecular weight of the cyclic group is in the range of 5 to 13. If it is less than 5, the low temperature properties will deteriorate, and if it is larger than 13, the effect of preventing deterioration and discoloration caused by light will be lost. Examples of organic diisocyanates include 4.
Examples include aromatic diisocyanates such as 4'methylene bisphenyl isocyanate and xylene diisocyanate, alicyclic diisocyanates such as methylene biscyclohexyl isocyanate and isophorone diisocyanate, and aliphatic diisocyanates such as hexamethylene diisocyanate.
However, if less discoloration and a lighter color are desired, alicyclic or aliphatic diisocyanates are preferable to aromatic diisocyanates. Examples of the chain extender include diols, diamines, alkanolamines, hydrazine hydrazide, aminohydrazide, etc., which have active hydrogen that can react with isocyanates having a molecular weight of less than 400. Specifically, for example, ethylene glycol, propylene glycol, 1,4-butanediol,
Diols such as 1,5 bentadiol and 1,6 hexanediol, diamines such as ethylene diamine, 1,2 propylene diamine, hexamethylene diamine, diaminodiphenylmethane, and diaminobicyclohexylmethane, monoethanolamine,
Examples include alkanolamines such as diethanolamine, dicarboxylic acid hydrazides such as oxalic acid hydrazide, maleic acid hydrazide, and fumaric acid hydrazide, and aminocarboxylic acid hydrazides such as glycine hydrazide and β-alanine hydrazide. The chain extender must have a low molecular weight of 400 or less in order to satisfy the hardness, heat resistance, solvent resistance, etc. of the coating film required as a resin for finishing paint; This is not preferred because the film has poor heat resistance and solvent resistance. Further, the chain extender must be bifunctional and have two active hydrogens, and trifunctional or higher functional ones that do not yield a linear polyurethane resin cannot be used. In order to satisfy the physical properties required for a finishing paint resin such as hardness, heat resistance, and solvent resistance of the coating film, the value of [number of moles of chain extender]/[number of moles of polyalkylene oxide glycol] is 1.0. It is sufficient to adjust within the range of ~10, 1.0 to 6.0 for base resin and 4.0 for top resin.
A range of ~10 is preferred. When polymerizing these raw materials, it is appropriate to use amide solvents such as dimethylformamide and dimethylacetamide, which are good solvents for polyurethane resins. Polymerization methods include the one-shot method in which the raw materials are reacted simultaneously, or the polymer diol and organic diisocyanate. Any prepolymer method may be used, in which a chain extension agent is added to perform a chain extension reaction after reacting in advance. Its degree of polymerization is wear resistant,
In order to satisfy durability such as crack resistance, a higher degree of polymerization is preferable, but in order to satisfy finish coating workability and durability, an appropriate degree of polymerization is preferred. Although there are some differences depending on the type of solvent, it is preferable that the intrinsic viscosity is about 0.8 to 1.0 when measured in a dimethylformamide solvent at 30°C. To obtain a finishing paint from the resulting polyurethane resin solution, the viscosity is adjusted to an appropriate level using a solvent such as methyl ethyl ketone, toluene, or isopropyl alcohol. Of course, the resin solution can be mixed with colorants such as colored dyes and pigments, and stabilizers such as antioxidants and ultraviolet absorbers. The modulus of a paint film differs depending on whether it is used as a base paint or a top paint, but in the case of a base paint, the stress at 5% elongation is 0.08.
~0.3Kg/cm ² , preferably 0.35Kg/mm ² or more in the case of top paint. In addition to adjusting the modulus by adjusting the composition of the polyurethane resin, it is also possible to add extender pigments, such as calcium carbonate and barium sulfate, to a low modulus polyurethane resin suitable for use as a base paint. The modulus can be increased by adding an appropriate amount of silica or the like. The artificial leather closure according to the present invention is produced, for example, by the following method. Preparation of artificial substrate (parts are shown in parts by weight) Polybutylene adipate (molecular weight 1729) 216.9
Part and polyethylene glycol (molecular weight 1561) 60.0
part, polytetramethylene glycol (molecular weight
1560) 195.4 parts, bis(-βhydroxyethoxyphenyl)-propane 70.0 parts, 4.4′ diphenylmethane diisocyanate 371.2 parts, were dissolved in 228.4 parts of methyl ethyl ketone, and after adding 0.05 part of triethylamine, the mixture was heated at 65°C for 90 minutes. Made it react. Next, it was diluted to 50% with methyl ethyl ketone, 86.4 parts of 1,4-butanediol and 1.5 parts of triethylamine were added, and while adjusting the liquid temperature to 68 to 72°C, methyl ethyl ketone was added and a chain elongation reaction was performed for 4 hours, resulting in a final concentration of 20
A polyurethane slurry with a viscosity of 1200 cps/70°C was obtained. Next, the above polyurethane slurry
Add 5 parts of methyl ethyl ketone, 0.5 parts of isoparaffin, 0.1 part of antioxidant, and 1 part of titanium oxide to 100 parts and mix uniformly with a homomixer, then add 25 parts of water little by little while stirring with a homomixer. A water mixed dispersion of 2200 cps/42°C was obtained. This water-mixed dispersion was applied to a needle-punched fiber mat made of highly shrinkable polyester fibers, which was shrunk to 50% of its original area in hot water, and the hydrated mat was passed through a drum pressure dryer to an apparent thickness of 1.2 mm. Density 0.32g/ ^cm3
The same water mixed dispersion was applied to one side of the nonwoven fabric to a thickness of 1.0 mm without drying, and most of the solvent was evaporated in a humid box at 40°C and 80% RH. Then, residual solvent and part of the water were removed at 80°C, and finally drying was performed at 110°C. The characteristic values of the obtained artificial leather substrate are as follows. This was used in the next example. Note that the method for measuring characteristic values is also common to the following examples.

[Table] Example 1 (1) Using bis4.4'hydroxyphenylpropane as an initiator, ethylene oxide was subjected to ring-opening addition polymerization to bis(-4.4'hydroxyphenyl(-
A polymer diol with a molecular weight of 2050 containing at least one propane in the molecular chain was obtained. 618 parts of this polymer diol and 5 isocyanate-3.
After reacting with 287 parts of 3.5 trimethylcyclohexyl isocyanate at 95°C for 180 minutes under a nitrogen stream, the mixture was cooled to 40°C, and dehydrated dimethylformamide was added to give a concentration of 40%. Next, 95 parts of 1,4-butanediol were added, and 0.05 part of dibutyltin dilaurate was added to carry out a chain extension reaction at 40°C. Dimethylformamide was additionally added to prevent the viscosity from becoming excessive, and after 6 hours of reaction, di- Add 2.5 parts of n-butylamine to a final concentration of 20
%, a viscous dope with a viscosity of 300 poise/30°C was obtained. This was further diluted to 10% with a mixed solvent of tetrahydrofuran x methyl ethyl ketone = 1/1, and 2 parts of titanium oxide and 0.05 parts of Irganox 1010 (antioxidant, Ciba Geigy) were added to 100 parts of this solution to form a colloid. The mixture was uniformly dispersed in a mill to create a base paint (hereinafter abbreviated as B paint). (2) 469 parts of the same polymer diol and 387 parts of 5-isocyanate, 3.3.5-trimethylcyclohexyl isocyanate, were reacted at 95°C for 120 minutes under a nitrogen stream, then cooled to 40°C, and the dehydrated dimethylformamide was reacted. was added to give a concentration of 40%. Next, 144 parts of 1,4-butanediol and 0.05 part of dibutyltin dilaurate were added, a chain elongation reaction was carried out at 40°C, dilution was performed successively with dimethylformamide, the reaction was allowed to proceed for 3 hours, and then 2.5 parts of di-n-butylamine was added to adjust the concentration. 20% viscosity 220 poise/
A dope at 30°C was obtained. This was further diluted to 10% with a mixed solvent of tetrahydrofuran/methyl ethyl ketone = 1/1, and 0.1 part of titanium oxide and 0.05 part of Irganox 1010 were added to 100 parts of this solution and uniformly dispersed in a colloid mill to form a top coating. (hereinafter abbreviated as T paint) was created. Next, 6 rolls of base paint and 2 rolls of top resin were applied to the artificial leather substrate using a 150 mesh gravure roll. The physical properties of the obtained artificial leather are shown in Table 1-(3). The artificial leather using the polymer glycol of the present invention showed significantly improved deterioration and discoloration due to light compared to Comparative Example 3 using only polyethylene glycol containing no bisphenylpropane group. Example 2 Using bis(-4·4'hydroxyphenyl)-propane as an initiator, propylene oxide was added to synthesize bis(-ω hydroxypolypropoxyphenyl)-propane with a molecular weight of approximately 640, and further ethylene oxide was added. Bis(-ω hydroxypolyethoxy polypropoxyphenyl)-propane with a molecular weight of 1980 was synthesized. The ratio of polypropylene oxide and polyethylene oxide in the polyalkylene oxide component of this polymer glycol is approximately 25% each.
%, 75%. Using this, a paint was created in the same manner as paint B in Example 1, and artificial leather was created. The obtained artificial leather has slightly lower moisture permeability than Example 1, but its light deterioration resistance is superior to Comparative Example 3 using only conventional polyalkylene ether. Comparative Example 1 Similar to Example 2, bis(-ω hydroxy polyethoxy polypropoxyphenyl) with a molecular weight of 2038 was used, with the contents of polypropylene oxide and polyethylene oxide as polyalkylene oxide components in the polymer glycol being 40% and 60%, respectively. )-propane was synthesized. The obtained artificial leather had a lower moisture permeability than Examples 1 and 2. Comparative Example 2 Examples 3 to 6 In the same manner as in Example 1, ethylene oxide was reacted using bis(-4·4'hydroxyphenyl)-propane as an initiator, and the molecular weight shown in Table 1-(1) was 722.
(Comparative Example) Bis(-ω-hydroxypolyethoxyphenyl)-propanes of 958, 2736, 3096, and 3998 (Examples 3 to 6, respectively) were synthesized. A reaction was carried out at the same molar ratio as in Example 1 to prepare a paint, and artificial leather was prepared. As shown in Table 1-(3), Comparative Example 2, in which the molecular weight of the polymer glycol is small, has low moisture permeability, which is undesirable, and Example 6, in which the molecular weight is large, has a small effect of the bisphenylpropane groups contained in the polymer glycol, resulting in poor light deterioration resistance. , inferior in terms of yellowing. Example 7 Polymer glycol with a molecular weight of 2022 to which ethylene oxide was added using bis(-βhydroxyethoxycyclohexyl)-propane as an initiator
A coating material was prepared in the same manner as in Example 1 by reacting dicyclohexylmethane 4,4' diisocyanate as the diisocyanate and hexamethylene diamine as the chain extender. The characteristics of the artificial leather were as shown in Table 1-(3). Example 8 Bis(-4,4'hydroxycyclohexyl)-pentane as the polymer glycol as an initiator,
Molecular weight obtained by adding ethylene oxide: 1989
A polyurea resin obtained by reacting the diol with hexamethylene diisocyanate as a diisocyanate and diaminocyclohexylmethane as a chain extender in the same molar ratio as in Example 1 was made into a paint in the same manner as paint B in Example 1. Created artificial leather. The yellowing resistance and light deterioration resistance were excellent as in Example 1. Example 9 Bis(-βhydroxyethoxycyclohexyl)-
A polyurethane resin was obtained by reacting a polymer glycol with a molecular weight of 1995 obtained by adding ethylene oxide to propane, xylene diisocyanate as a diisocyanate, and 1,4-butanediol as a chain extender at the same molar ratio as in Example 1. Artificial leather was made into a paint using the same method as the B paint in Example 1. Although the yellowing resistance was slightly low, the light deterioration resistance was excellent as in Example 1. Example 10 Example 9 was carried out using diphenylmethane 4,4' diisocyanate instead of xylylene diisocyanate. Yellowing resistance was poor when exposed to a weather meter for a long time, but light deterioration resistance was excellent. Comparative Example 3 The same reaction as in Example 1 was carried out except that polyethylene glycol with a molecular weight of 2048 consisting only of polyoxyethylene chains was used as the polymer diol.
A paint and a T-paint were prepared, and the B-paint was coated and then the T-paint was applied under the same conditions as in Example 1 to obtain artificial leather. In both cases, the light deterioration resistance was significantly inferior to that of Example 1, and yellowing was also insufficient. Example 11 Molecular weight 1650 obtained by adding ethylene oxide to bis(-βhydroxyethoxyphenyl)-methane
523 parts of polymer glycol and ωω' diisocyanate 1,4 dimethylcyclohexane (DIMCH)
After reacting with 379 parts at 95°C for 180 minutes under a nitrogen stream, it was cooled and dissolved in dehydrated dimethylformamide to a concentration of 40%, then 98 parts of ethylene glycol and 0.1 part of triethylene amine were added, and the mixture was reacted at 35°C. After diluting with dimethylformamide to prevent the viscosity from becoming too high and reacting for 4 hours, 2.5 parts of di-n-butylamine was added to give a viscous solution with a final concentration of 20% and a viscosity of 160 poise at 30°C. Got dope. A finishing paint was prepared in the same manner as in Example 1 and applied to the artificial leather substrate.

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Claims (1)

[Scope of Claims] 1. A polyurethane resin on the surface of an artificial leather substrate consisting of a fibrous base material and a polymeric elastic material, in which a continuous porous layer of the polymeric elastic material is formed in the fibrous base material. In the artificial leather coated with the polyurethane resin, (1) an organic diisocyanate, (2) a low molecular chain extender having a molecular weight of 400 or less, and (3) a polyurethane resin comprising an alkylene oxide having 2 to 4 carbon atoms and a molecular weight of 900 to 3,500. The alkylene oxide glycol must contain at least one cyclic group of the unit shown below in its molecular chain, and the polyalkylene oxide component must consist of a polymer diol in which the component based on polyoxyethylene chains accounts for 50% or more. Artificial leather featuring In the formula, R ₁ and R ₂ represent a C ₁ -C ₃ alkyl group or hydrogen, and X represents hydrogen, Cl or Br. 2. The artificial leather according to claim 1, wherein the organic diisocyanate is an alicyclic or aliphatic diisocyanate. 3. The artificial leather according to claim 1, wherein the polymer diol is a polymer diol in which the ratio of the cyclic group to the molecular weight of the polyalkylene ether portion excluding the cyclic group is 5 to 13.