JPH0314948B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a synthetic leather for vehicles made of polyurethane synthetic resin, which has excellent light resistance and hydrolysis resistance, and has long-term heat resistance of 100 to 120°C. The purpose is to The well-known general polyester polyurethane synthetic leather closely resembles natural leather in texture and appearance, so it is mainly used as a fashion material with a relatively short fashion cycle, such as bags, bags, footwear, and clothing. Although it is widely used, it has not been widely adopted as a long-lasting furniture and vehicle interior material due to its disadvantage of hydrolyzability, which causes it to become brittle after two to three years. It is well known that improvements were strongly desired. For this reason, recently, attempts have been made to (1) improve the hydrolysis resistance using polyether-based polyurethane, or (2) propose polyurethane synthetic leather with improved light resistance and hydrolysis resistance using polycarbonate-based polyurethane. However, (1) polyether-based polyurethane has poor light resistance and heat resistance, and (2) polycarbonate-based polyurethane has insufficient heat resistance. Even if its hydrolyzability is improved, it can only withstand indoor temperatures and has the same long-term heat resistance for general furniture, and is still inadequate for use as synthetic leather for vehicles, which requires long-term heat resistance of 100 to 120°C. It was sufficient. Synthetic leather originally has texture (flexibility), surface friction strength,
It is most desirable that the bending resistance etc. closely resemble that of natural leather, but in addition to the above-mentioned texture etc., it is also desirable to impart light resistance, hydrolysis resistance, and long-term heat resistance to synthetic leather. In order to achieve this, it is preferable that the surface layer of the polyurethane layer formed on the substrate has the highest light resistance.
In addition, hydrolysis resistance is required for both the base material surface and the surface layer on the opposite side, and heat resistance is also required not only for the base material and the surface but also for the intermediate part of the polyurethane layer. It has been confirmed that in order to satisfy these requirements, it is impossible to achieve this with a single type of polyurethane layer, and that it is most desirable to use a laminate of two or more types of polyurethane. In addition to various polyols as materials for the polyurethane layer, various isocyanate compounds (hereinafter abbreviated as isocyanates) that react with the polyols are also known, and the properties of polyurethane vary depending on each of the materials. As shown in Table 1, it is recognized that there are differences.

[Table] Furthermore, based on the results of Table 1 above, Table 2 shows various physical properties when various polyurethane layers are laminated on a base material.

【table】

[Table] The results in Table 2 show that the three-layer structure (No. 6) consisting of a polycarbonate-based polyurethane adhesive layer, a polyester-based polyurethane middle skin layer, and a polycarbonate-based polyurethane adhesive layer has significantly superior physical properties, especially the middle skin layer. It can be seen that it shows superiority over non-laminated products. The present invention has been achieved as a result of the above-mentioned findings, and has a 100% modulus of 10 to 50 kg/
cm ² , 30~150μ thick polycarbonate polyurethane adhesive layer, 100% modulus 40~100Kg/
cm ² , thickness 10 to 50 μm polyester-based polyurethane medium layer made of −(CH ₂ −) number 4 or higher glycol dicarboxylic acid; skin layer made of polycarbonate polyurethane with 100% modulus 80 to 200 Kg/cm ² and thickness 10 to 50 μm. This synthetic leather for vehicles is characterized by being sequentially layered. To further explain the present invention in detail, the fibrous base material used in the present invention includes natural fibers such as cotton, wool, silk, and hemp; regenerated fibers such as rayon, viscose cotton, and acetate; and polyester, polyacrylonitrile, and polychloride fibers. vinyl, polyamino acids,
These include knitted fabrics, nonwoven fabrics, etc. made of synthetic fibers such as polyvinylidene chloride or various blended fibers, or inorganic fibers such as glass fibers and asbestos fibers. In the present invention, a polycarbonate-based polyurethane adhesive layer, a polyester-based polyurethane intermediate skin layer, and a polycarbonate-based polyurethane skin layer are sequentially laminated on the fibrous base material. The polycarbonate polyurethane used in the present invention is a polymer of a polycarbonate polyol, an isocyanate, and a chain extender, and the polycarbonate polyol has the following general formula: (However, R = - (CH ₂ -) _p and p≧2. Also, n = 5 to 200) It is a polyalkylene polycarbonate polyol represented by the formula, specifically 1,6-hexane polycarbonate polyol. is preferred. Further, a mixture in which a part of the polyalkylene polycarbonate polyol is replaced with polyoxyalkylene modified polycarbonate can also be used. In addition, the isocyanate is a non-yellowing type aliphatic or alicyclic diisocyanate, such as tetramethylene diisocyanate; 1,6-hexane diisocyanate; 2,2,4-trimethyl-
1,6-hexane diisocyanate; 1-methylcyclohexane-2,4-diisocyanate;
3,3'-dimethyl-4,4'-diisocyanate dicyclohexylmethane; 4,4'-dicyclohexylmethane diisocyanate, etc. can be used. Further, as the yellowing type in the present invention, aromatic diisocyanates such as tolylene diisocyanate; diphenylmethane diisocyanate; xylylene diisocyanate and the like can be used. In addition, the chain extender may be a primary or secondary aliphatic diamine or a low molecular weight glycol, such as piperazine; hexamethylene diamine; ethylene diamine; propylene-1,2-diamine;
N-methyl-bis-(3-aminopropyl)amine; 1,4-diaminocyclohexane; 1-amino-3-aminomethyl-3,5,5-trimethyl-cyclohexane; 1,4-butanediol; ethylene glycol; 1,6-hexanediol;
Neopentyl glycol; P-xylene glycol, etc. can be used. Furthermore, the polyester polyurethane used in the present invention is a polymer of a polyester polyol, an isocyanate, and a chain extender, and the polyester polyol is composed of a glycol dicarboxylic acid having -( _CH2- ) number of 4 or more. It is a polyester polyurethane, and dicarboxylic acids such as adipic acid, sebacic acid, glutaric acid, succinic acid, azelaic acid, etc. can be used, and glycols include ethylene glycol; 1,4-butanediol: 1,6-hexanediol. ; diethylene glycol; neopentyl glycol, etc. can be used. The diisocyanate and chain extender used in the polyester polyurethane can be the same as those used in the polycarbonate polyurethane described above. In the synthetic leather for vehicles according to the present invention, polycarbonate polyurethane having a 100% modulus of 10 to 50 kg/cm ² is laminated to a thickness of 30 to 150 μm on the above-mentioned fibrous base material to form a polycarbonate polyurethane adhesive layer. If the 100% modulus is less than 10 Kg/cm ² , the peel strength will be weak, and if it exceeds 50 Kg/cm ² , the adhesive layer will become too hard, impairing the texture, creasing properties, and feel that closely resemble natural leather. In this case, the polycarbonate polyurethane used may be either a polycarbonate polyurethane or a copolymer of a polycarbonate polyurethane and a polyether polyurethane, such as polytetramethylene ether glycol or polyoxypropylene glycol. Further, on the surface of the adhesive layer, a polyester polyurethane medium layer made of a glycol dicarboxylic acid having -( _CH2- ) number 4 or more is formed with a thickness of 10 to 50μ and a 100% modulus of 40 to 100Kg/ ^cm2.
A polycarbonate-based polyurethane skin layer with a 100% modulus of 80 to 200 kg/cm ² is laminated to a thickness of 10 to 50μ on the surface of the intermediate skin layer, resulting in a 4-layer structure including the fibrous base material. It is formed by laminating layers. In this case, if the 100% modulus of the mesodermal layer is less than 40 kg/cm ² , the adhesiveness will be weak and the physical properties will be poor. Furthermore, if the 100% modulus exceeds 100 Kg/cm ² , the feel of the mesodermal layer will be impaired, and the appearance of fine wrinkles on the surface that closely resembles natural leather will not be obtained. Furthermore, the 100% modulus in the epidermal layer is 80
If it is less than 200 kg/ ^cm2 , the physical properties of the epidermis layer will be poor.
If it exceeds Kg/cm ² , the skin layer becomes too hard and the texture, creasing, and feel that closely resembles natural leather are lost. For the polycarbonate polyurethane used in the skin layer, either a yellowing type or a non-yellowing type diisocyanate can be used as an isocyanate that reacts with the polycarbonate polyol, but if the discoloration required for the skin layer is taken into consideration, no It is preferable to use a yellowing type diisocyanate, and in order to give it appropriate color tone and light-shielding properties, one or two of pigments such as titanium oxide, carbon black, flavance yellow, anthraquinone red, copper phthalocyanine blue, etc. are used. The above can be added in an amount of 5 to 50% by weight based on the polycarbonate polyurethane. In addition to these pigments, ultraviolet absorbers, ultraviolet shielding agents, crosslinking agents, and other fillers can be added as necessary. It can be appropriately blended into the layer. That is, in the present invention, the 100% modulus of the polycarbonate polyurethane, polyester polyurethane, and polycarbonate polyurethane forming the adhesive layer, medium skin layer, and skin layer is 10 to 50 Kg/cm 2 , 40 to 100 Kg/cm ² , and 80 Kg/cm ² , respectively. ~
200Kg/cm ² improves the peel strength between the polyurethane layers, and the polyurethane layers are sequentially formed from coarse to dense, and each polyurethane layer interferes with each other at the interface, so it is difficult to bond to natural leather. Focusing on the similar properties and excellent heat resistance of polyester polyurethane,
The hydrolyzability of the polyester-based polyurethane is improved by coating both sides with an adhesive layer and a skin layer made of polycarbonate-based polyurethane with excellent hydrolysis resistance, and the synergy between polycarbonate-based polyurethane and polyester-based polyurethane is improved. As a result, it is possible to make synthetic leather that retains a texture and wrinkle properties that closely resemble those of natural leather, and has excellent heat resistance, hydrolysis resistance, and light resistance. In particular, the present invention has heat resistance to high temperatures of 100 to 120° C. for a long period of time, and is therefore particularly excellent as a synthetic leather for vehicles that requires long-term durability. Example 1 100% modulus 120Kg/cm ² on release paper with diaphragm
100 parts by weight of 1,6-hexane carbonate polyurethane resin solution (contains 15 parts by weight of titanium oxide)
Dry thickness is 30μ using a doctor knife coater.
The coating layer is coated so as to have the following properties, and further heat-dried at 100°C to form a polycarbonate-based polyurethane film layer, which is used as the skin layer. Next, apply 100% Modulus 80 on the surface of the epidermis layer.
Kg/cm ² of polyester (adipic acid) polyurethane solution was applied using a doctor knife coater as described above to a dry thickness of 30 μm, and dried to form a polyester polyurethane film layer, which was used as the intermediate skin layer. In addition, 100% modulus 20 is added to the surface of the mesothelial layer.
Kg/cm ² of 1,6-hexane carbonate-tetramethylene ether copolymer polyurethane adhesive is applied at a basis weight of 200 g/m ² , and the raised side of a cotton-fleeved cloth is laminated on this surface as a base material at 120°C. After heating for 10 minutes to cure the adhesive, the release paper was peeled off to obtain synthetic leather. Comparative Example 1 Synthetic leather was prepared in the same manner as in Example 1, except that polyether (tetramethylene ether) polyurethane was used for the outer skin layer and the middle skin layer. Comparative Example 2 Synthetic leather was prepared in the same manner as in Example 1 except that polyether (tetramethylene ether) polyurethane was used for the adhesive layer. The synthetic leathers obtained in Example 1, Comparative Example 1, and Comparative Example 2 were tested for light resistance, heat resistance, and hydrolysis resistance under the following conditions, and Table 3 shows the results. (1) How to measure light resistance A sample piece of synthetic leather was placed on a black panel at a temperature of 83°C.
The specimen was left in a fade meter for 400 hours, and then tested with a Taber abrasion tester at a load of 1 kg.
The surface condition was observed after 2000 wear recovery cycles. (2) Method for measuring heat resistance A synthetic leather sample piece was left in a gear type aging tester at 120℃ for 400 hours, and then the surface condition was measured using a Taber type abrasion tester at a load of 1 kg and abrasion number of 2000 times. observed. (3) Method for measuring hydrolysis resistance A sample piece of synthetic leather was heated at a relative humidity of 95% and a temperature of 70°C.
The specimen was left under the following conditions for 4 weeks, and then tested using a Taber type abrasion tester at a load of 1 kg and 2000 abrasion cycles.
The surface condition was observed at two times.

[Table] As is clear from Table 3, the synthetic leather of the present invention is not only comparable in light resistance and hydrolysis resistance to the products of Comparative Examples 1 and 2, but also
It is recognized that the product has excellent long-term heat resistance to 120°C, which is completely unobtainable from the products of Comparative Examples 1 and 2.

Claims (1)

[Claims] 1. 100% modulus 10 to 50 kg/ on fibrous base material
cm ² , 30~150μ thick polycarbonate polyurethane adhesive layer, 100% modulus 40~100Kg/
cm ² , thickness 10-50μ, non-foamed polyester polyurethane medium layer made of glycol dicarboxylic acid with -(CH ₂ -) number 4 or more, 100% modulus 80-200
A synthetic leather for a vehicle, characterized in that polycarbonate-based polyurethane skin layers having a weight of kg/cm ² and a thickness of 10 to 50 μm are sequentially laminated. 2. The synthetic leather for vehicles according to claim 1, characterized in that the skin layer of the polycarbonate-based polyurethane contains a coloring pigment and a filler having light-shielding properties.