JPH086264B2 - Wrinkled synthetic leather similar to natural leather and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to synthetic leather, particularly synthetic leather suitable for furniture sheet materials, and a method for producing the same.

[Conventional technology]

Conventionally, polyurethane synthetic leather has been used for various purposes because of its excellent texture and appearance. However, since most of the conventional polyurethane synthetic leathers use polyester polyurethane as the material, when used for a long period of time, the hydrolysis of the polyester polyurethane causes a long period of time such as furniture seats, vehicle seats, and high-class clothing. The product that needs to be used for a long time cannot be used at all.

Of course, it is possible to improve the properties to some extent by adding a hydrolysis inhibitor such as polycarbodiimide to the polyester polyurethane component, but it is not possible to expect substantial improvement.

[Problems to be solved by the invention]

On the other hand, polycarbonate polyester-based polyurethane is known as a polyurethane excellent in light resistance and hydrolysis resistance, but this requires an extremely complicated process in manufacturing, and the raw material is not general-purpose and expensive, so that For all laminates, especially those with fibrous substrate layers and microporous coating layers, it is economically expensive and practically difficult to form these layers with polycarbonate polyester-based polyurethane.

An object of the present invention is to provide a synthetic leather which has flexibility by utilizing the characteristics of the polyester-based polyurethane and has excellent texture, appearance and durability, and a method for producing the same.

[Means for solving problems]

The present invention is, (1) attachment woven, knitted, nonwoven, etc. fibrous tissue composed mainly of a polyether-based polyurethane and 100% modulus value 150~400kg / cm ² to polypropylene glycol polyol component fibrous tissue , A fibrous substrate layer which is impregnated to impart foldability to the fibers of the tissue by solidifying the components, and polypropylene glycol as a polyol main component 100
% Modulus value 15 to 100 kg / cm ² Polyurethane polyurethane microporous coating layer and polytetramethylene glycol as the polyol component 100% modulus value 15
〜50kg / cm ² of polyether-based polyurethane, bond coat forming a continuous coating on the microporous coating layer, 100% modulus 200-600kg / cm ² of polycarbonate polyester-based polyurethane, yield value And a synthetic leather capable of forming wrinkles like natural leather, characterized in that a top coat forming a continuous film is laminated and integrated on the binding coat, and a method for producing this synthetic leather, that is, (2) A fibrous base layer is formed by adhering and impregnating a fiber system with a polyether polyurethane having a polypropylene glycol as a polyol component and a 100% modulus value of 150 to 400 kg / cm ² , and then wet treating the surface of the base layer. A microporous coating layer is laminated and polytetramethylene glycol is used as a polyol component. 100% modulus value 15 to 50 kg / cm ²
Of the polyether-based polyurethane of 10 to cover the surface of the microporous coating layer through a bond coat forming a continuous film.
A method for producing wrinkle-like synthetic leather similar to natural leather, characterized by covering with a continuous topcoat of a polycarbonate polyester-based polyurethane having a 0% modulus value of 200 to 600 kg / cm ² and a yield value. is there.
According to the production method of the present invention, the obtained synthetic leather is subjected to a rubbing process to be provided with wrinkles similar to natural leather, so that the texture of the base material layer can be obtained.

[Principle / Action]

For the polyurethane used to form the fibrous base layer and the microporous coating layer, a polyether polyurethane having polypropylene glycol as the polyol component, which is an inexpensive raw material, is used for the polyurethane, and the ventilation to the microporous coating layer as a synthetic leather substrate is substantially achieved. By preventing it, the synthetic leather has excellent light resistance, hydrolysis resistance, and durability as a whole.

Polyether polyurethane is inherently poor in light resistance. Here, the polyether-based polyurethane refers to polyurethane having polypropylene glycol and / or polytetramethylene glycol as a polyol component. In particular, when the surface area is large like the microporous layer, the contact area with the air is increased, and it is significantly susceptible to oxidative deterioration and deterioration due to ultraviolet rays.

Therefore, at least in order to improve the light resistance of the polyether polyurethane, the supply of air into the microporous coating layer is blocked as much as possible, and the microporous coating layer does not have a hydrolyzable group. It is possible to improve the hydrolysis resistance by using a polyether polyurethane. Further, in order to improve light resistance and hydrolysis resistance, a continuous coating having an appropriate thickness is laminated on the surface of the microporous coating layer to provide a synthetic leather having excellent durability and each constituent layer. By changing the hardness of
A synthetic leather with a texture, feel and wrinkles that closely resembles that of natural leather can be obtained.

 The present invention will be described below with reference to the drawings.

In FIG. 1, the synthetic leather of the present invention is, as shown in FIG. 1, a fibrous substrate layer 1 in which a polyether polyurethane having polypropylene glycol as a polyol component is impregnated and attached to a fiber, and a polypropylene containing polypropylene glycol as a polyol main component. A microporous coating layer 2 of ether polyurethane, a continuous coating bond 3 of polyether polyurethane containing polytetramethylene glycol as a polyol component, and a top coat 4 of continuous coating of polycarbonate polyester polyurethane are laminated and integrated. It was done.

The synthetic leather of the present invention is a polyether polyurethane having a polyol component of polypropylene glycol in which a fibrous substrate layer 1 impregnated with a polyether polyurethane having polypropylene glycol as a polyol component is added with a nonionic surfactant as a coagulation regulator. A microporous coating layer 2 is applied to the surface of the fibrous substrate by applying a solution and wet processing.
And then on the surface of the microporous coating layer, a bond coat 3 of a continuous coating comprising a polyether-based polyurethane containing polytetramethylene glycol as a polyol component.
And a continuous coating of a top coat 4 made of polycarbonate polyester polyurethane are laminated by a transfer method to produce an integrated synthetic leather, and the synthetic leather is further subjected to a kneading process.

 The configuration of the present invention will be specifically described below.

As the fibrous base material, woven cloth, knitted cloth, non-woven cloth or the like made of natural fibers or synthetic fibers is used, and this base material is impregnated with a polyether polyurethane elastomer containing polypropylene glycol as a polyol component. The preferred range of the 100% modulus value of the impregnated polyether polyurethane is 150 to 400 kg / cm ² . 100% modulus is 150 kg
If it is less than / cm ^2, it has a rubber-like texture, which is a drawback of polyether polyurethane, and a texture with a good drape cannot be obtained. When the 100% modulus value is 400 kg / cm ² or more, the rubber-like texture is not obtained, but the hard texture is not preferable. Impregnating a base material with a polyether-based polyurethane having a 100% modulus value of 150 to 400 kg / cm ² makes it possible for the polyurethane that has been impregnated and adhered to the fibers when the final product is subjected to a rubbing process to give breakability to the fibers. Each part of the above is folded and the texture of the fibrous base material is used to obtain a very soft and rich drape texture.
Impregnation amount of polyether polyurethane is based on fiber weight
It is preferably within 100%.

Further, a microporous coating layer 2 of polyether-based polyurethane containing polypropylene glycol as a main component of polyol is formed on the base layer 1 by a wet process. Polyether-based polyurethane containing polypropylene glycol as a main component is extremely widely used, economically advantageous, and has no hydrolyzable group. The proportion of polypropylene glycol in the polyol component in the polyether polyurethane is 60 to 100%.

Palmitate monostearate is generally known to be effective as a coagulation regulator for forming micropores in the wet cells formed in the microporous coating layer 2. But,
In order to use this for forming the microporous coating layer 2 of the present invention, a considerably large amount is required, and even after the solvent removal, the coagulation controlling agent is contained in the microporous coating layer 2 even if the washing step is repeated. Remains in a considerably large amount and migrates to the surface during drying to form an oil film, which is a disadvantage because the adhesiveness with the bond coat 3 is significantly impaired. Then, as a result of extensive studies including natural fats and oils, it was found that the castor oil-based surfactant, which is a nonionic surfactant, is a coagulation regulator which is satisfactory in all respects. It should be noted that cellulose fine powder, a coloring agent, calcium carbonate, and various stabilizers such as an ultraviolet absorber and an antioxidant can be added for the purpose of improving wet film-forming property and feeling of the polyether polyurethane. It is necessary to carefully determine the kind of the additive and the amount of the additive in consideration of the light resistance, hydrolysis resistance and physical properties of the microporous coating layer.

A solvent solution of a polyether-based polyurethane containing these additives is applied onto the fibrous substrate layer 1 impregnated with the polyether-based polyurethane, coagulated and desolvated in water,
Further, washing is repeated in warm water and dehydration drying is performed to form the microporous coating layer 2 having fine pores.

The 100% modulus value of the polyether type polyurethane used for coating is 15 to 100 kg / cm ² . 100% modulus
When it is 15 kg / cm ² or less, the texture becomes soft, but the physical properties are weak and not practical, and when it is 100 kg / cm ² or more, the physical properties are improved but the texture becomes hard, which is not preferable.

Further, the thickness of the microporous coating layer 2 is preferably 100 to 2,000 μ. If the thickness is 100 μm or less, it is not preferable because it lacks flexibility and the volume feeling is poor, and if it is 2,000 μm or more, it becomes thick and wrinkled, which is not preferable. Next, the bond coat 3 and the top coat 4 need to be processed into a continuous film without pinholes.

For the bond coat 3, a polyether polyurethane having polytetramethylene glycol as a polyol component is used. In addition to the colorant, an ultraviolet absorber, a radical scavenger, an antioxidant and the like can be added to the polyether polyurethane as required.

Further, a crosslinking agent having a polyisocyanate may be added to the polyether-based polyurethane used for the bond coat 3 if necessary for the purpose of improving physical properties such as solvent resistance and chemical resistance. It is necessary to determine the addition amount of the crosslinking agent in consideration of the hardness of the bond coat 3 and the balance with the feel of the synthetic leather as a whole.

The polyether polyurethane used for the bond coat 3 is
It must have physical properties with a 100% modulus value of 15 to 50 kg / cm ² . When the 100% modulus is 15 kg / cm ² or less, physical properties are weak and a practical synthetic leather cannot be obtained, and when it is 50 kg / cm ² or more, the texture becomes hard, and wrinkles are less likely to enter. Moreover, the wrinkles cannot be retained for a long time. The thickness of the polyurethane bond coat 3 is 10
If it is less than 10 μ, the physical properties are weak, and if it is more than 60 μ, the feel becomes hard, which is not preferable.

The top coat 4 must be a coating layer formed of polyurethane having excellent light resistance and hydrolysis resistance.

As a polyurethane generally used for a top coat, a polyester-based polyurethane obtained by adding an aliphatic or alicyclic diisocyanate to a polyester polyol obtained by reacting a glycol having 2 to 6 carbon atoms with a dibasic acid such as adipic acid Polycarbodiimide and other hydrolysis inhibitors, benzimidazole-based, benzophenone-based UV absorbers, phenol-based antioxidants, etc. can also be used, but the durability of the furniture sheet material of the present invention can be used. It is unsuitable for those requiring sex.

However, if only the hydrolysis resistance is to be improved, polytetramethylene glycol and polypropylene glycol can be sufficiently satisfied as the polyol component, but they cannot be used as a polyurethane for a top coat because of their extremely poor light resistance.

By the way, the microporous coating layer 2 and the bond coat 3 are extremely excellent in hydrolysis resistance and inferior in light resistance due to the characteristics of the polyol component thereof, but such deterioration of each coating layer can be completely compensated. As a result of various studies on the raw materials for the polyurethane for the top coat, the polycarbonate polyester-based polyurethane was the most excellent and could completely satisfy the requirements.

As described above, a polycarbonate polyester-based polyurethane is used for the top coat, and a colorant, various additives and the like may be added to the polyurethane as required. Polycarbonate polyester polyurethane of top coat 4 has 100% modulus value of 200-600kg / cm
It must be ² and have a yield value. If it does not have a yield value, wrinkles do not occur, which is not preferable. If the 100% modulus is 200 kg / cm ² or less, the wrinkles are hard to enter, and if the 100% modulus is 600 kg / cm ² or more, the wrinkles are included but the texture is hard, which is not preferable. The thickness of the top coat is 3 ~
If it is less than 3μ, it is not possible to sufficiently suppress the deterioration of the polyether polyurethane of the lower layer, and there is substantially no wrinkling. If it is more than 10μ, the texture is Not only becomes hard, but also when wrinkles are added, inconveniences such as cracking in the top coat layer occur.

The polyether-based polyurethane and polycarbonate polyester-based polyurethane used in the present invention is a polymer of a polyether-based polyol or a polycarbonate polyester-based polyol, a diisocyanate compound and a chain extender, and the polyether-based polyol is generally polypropylene glycol or polytetrahydrofuran. Methylene glycol is used, and as the polycarbonate polyester-based polyol, 1,6-hexane polycarbonate-based polyol can be generally used.

As the diisocyanate compound to be reacted with the polyether polyol and the polycarbonate polyester polyol, tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, tetramethylene diisocyanate, hexanemethylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate and the like can be used.

Further, as a chain extender, ethylene glycol, 1,4-
Low molecular weight glycols such as butanediol, 1,6-hexanediol, neopentyl glycol, or piperazine, ethylenediamine, hexamethylenediamine, propylene-1,2-diamine, N-methyl-bis- (3-aminopropyl) amine Primary or secondary amines such as, 1,4-diaminocyclohexane, 1-amino-3-aminomethyl-3,5,5-trimethyl-cyclohexane can be used.

The top coat 4 and the bond coat 3 are laminated and integrated by the following steps. That is, the polycarbonate polyester-based polyurethane solution forming the top coat 4 is
After coating on a support having releasability, it is dried to form a pinhole-free continuous coating, and then the topcoat 4
A polyether-type polyurethane solution containing polytetramethylene glycol forming the bond coat 3 as a polyol component is applied thereon to form a continuous film in the same manner. After that, the surface on the side of the bond coat 3 of this laminated and integrated laminate is pressure-bonded onto the microporous coating layer to complete the synthetic leather. The bond coat 3 and the microporous coating layer 2 It is preferable to integrate with and by utilizing the adhesiveness after volatilization of the organic solvent or the adhesive state at the time of thermocompression bonding from the viewpoint of maintaining surface smoothness and feeling.

By further rubbing the synthetic leather, fine folds are attached to each part of the fibrous structure of the base layer 1, which has an extremely soft and drape-rich texture, and is rubbed by rubbing. , Wrinkles can also be held for a long time.

The kneading can be performed by hand kneading or mechanical kneading, but in the case of mechanical kneading, the synthetic leather having a better texture can be obtained by heating the synthetic leather at 100 to 130 ° C. To be

〔The invention's effect〕

As described above, according to the present invention, it is possible to use a polyether-based polyurethane containing polypropylene glycol as a polyol component, which is economically advantageous for the polyurethane impregnated into the fibrous base material and the polyurethane used for the microporous coating layer. Even though the bond coat is hydrolyzable and has a light resistance problem, a polyether-based polyurethane containing polytetramethylene glycol, which has good hydrolysis resistance as the polyol component, is used. By changing the hardness of each constituent layer using a polycarbonate polyester polyurethane with excellent hydrolyzability, it is possible to obtain a synthetic leather that has a texture, feel and wrinkle that closely resembles that of natural leather and that has excellent durability. You can

Further, according to the present invention, due to the synergistic effect of the polyurethane having a yield value formed in the outermost layer of the structure and the polyurethane impregnated into the fibrous base material, it is easy to get wrinkles, and by kneading, it is extremely soft and drapes. It has excellent properties and can keep creasing for a long time, so it closely resembles the appearance of natural leather, has excellent flexibility overall, has a texture that closely resembles natural leather, and has excellent long-term durability, especially furniture sheets. It is a synthetic leather suitable for long-term use.

〔Example〕

Examples of the present invention will be given below, but the present invention is not limited to these examples.

Thickness of blended polyester fiber and rayon fiber 0.
80m / m double-sided brushed cloth is impregnated with a dimethylformamide solution with a solid content of 10% of a polyether-based polyurethane containing polypropylene glycol with a 100% modulus of 250kg / cm ² as a polyol component, and a squeeze roll is used for each fiber weight. Squeeze the polyurethane solids content to 30%, then immerse it in water at 20 ° C, coagulate, desolvate and dehydrate
It was dried under hot air at 120 ° C., and further impregnated cloth having a thickness of 0.85 m / m obtained by passing between hot rolls was obtained.

Next, as a coating solution for forming a microporous coating layer, the following compounded solution consisting of a polyether polyurethane solvent solution (solvent DMF) containing 100% modulus 25 kg / cm ² of polypropylene glycol as a polyol component was prepared, It was applied to a thickness of 0.8 m / m on the impregnated cloth.

Applying the <coating solution formulation> parts ○ polyether based polyurethane solvent solution (solid content 30%) 100 ○ colorant 5 ○ castor oil surfactant 1. ⁵ ○ cellulose fine powder 5 ○ DMF 100 above coating solution to a substrate layer After that, coagulate and desolvate in 20 ° C water, dehydrate, and dry with hot air at 120 ° C
A fibrous substrate having a microporous coating layer of 1.0 m / m having extremely excellent surface smoothness was obtained. On the other hand, 100% modulus 300 kg / cm ² 1,6-hexanediol polycarbonate-based polyurethane solution with a yield value (solid content)
10%, containing 5 parts by weight of colorant) with a knife coater to a dry thickness of 5μ, and continuously dried with hot air in a dryer having a temperature gradient of 80 to 120 ° C to remove pinholes. A continuous coat top coat was obtained. Furthermore, a polyether-based polyurethane solution containing polytetramethylene glycol having a 100% modulus of 20 kg / cm ² as a polyol component (solid content: 20%, cross-linking agent: 5 parts by weight, coloring agent: 20 parts by weight) is further applied as a bond coat on the above. After coating with a knife coater to a dry thickness of 30 μm and drying with hot air at 100 ° C. for 2 minutes, the surface of the microporous coating layer was coated on the bond coat surface.
While heating to 0 ° C., thermocompression bonding was performed to integrate them, and after the bond coat was cured, the release paper was peeled off to obtain a synthetic leather. The synthetic leather obtained in this state is a hard one with no drape, and has a soft and drape property by mechanically rubbing the synthetic leather while heating it in an atmosphere of 110 ° C., and Wrinkles are retained for a long period of time, they are extremely flexible, and they have excellent durability such as hydrolysis resistance and light resistance, and their texture and appearance are very similar to natural leather, making them suitable as furniture sheet materials. It was

This synthetic leather sheet material did not show any change in appearance, texture, and physical properties even after 10 weeks in an atmosphere at a relative temperature of 90% and a temperature of 70 ° C. Furthermore, no change in appearance, texture, or physical properties was observed even after an ultraviolet irradiation test was conducted at 63 ° C with a fade meter for 200 hours.

[Brief description of drawings]

 FIG. 1 is an enlarged sectional view showing the basic structure of the present invention. 1 ... Fibrous substrate layer, 2 ... Microporous coating layer 3 ... Bond coat, 4 ... Top coat

Claims (2)

[Claims] 1. A woven fabric, a knitted fabric, a non-woven fabric or the like as a main component, and a 100% modulus-valued polyether polyurethane having polypropylene glycol as a polyol component of 150 to 400 kg / cm ² is adhered to and impregnated into the fiber structure. A fibrous substrate layer that imparts foldability to the fibers of the tissue by coagulation of the components, and a microporous coating layer made of polypropylene-based polyol-based polyether polyurethane with 100% modulus value of 15 to 100 kg / cm ^2. And a 100% modulus 15 to 50 kg / cm ² polyether polyurethane having a polytetramethylene glycol as a polyol component, a bond coat forming a continuous film on the microporous coating layer, and a 100% modulus value. Composed of polycarbonate polyester polyurethane of 200-600 kg / cm ² , has a yield value and forms a continuous film on the bond coat. Synthetic leather that can be wrinkled like natural leather, characterized by being laminated and integrated with a top coat. ^2. A fibrous base layer is formed by adhering and impregnating a fiber system with a polyether polyurethane having a polypropylene glycol as a polyol component and a 100% modulus value of 150 to 400 kg / cm ² , and then wet the surface of the base layer. Laminated microporous coating layer by treatment, polytetramethylene glycol as a polyol component 100% modulus value 15-50k
Polycarbonate polyester system composed of polyether polyurethane of g / cm ² and having 100% modulus value of 200 to 600 kg / cm ² and yield value on the surface of the microporous coating layer through a bond coat forming a continuous film. A method of producing wrinkle-like synthetic leather, which is similar to natural leather, characterized by covering with a continuous topcoat made of polyurethane.