JP2853573B2 - Water-repellent, waterproof and breathable nubuck synthetic leather - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nubuck-like synthetic leather, and more particularly to a nubuck-like synthetic leather excellent in water repellency, waterproofness and moisture permeability suitable for materials used for shoes, bags and the like.

[0002]

2. Description of the Related Art Recently, natural activities such as natural leather nubuck and nubuck-like materials have been increasingly used in the trend of fashion due to the importance of outdoor activities as recreation. Like nubuck finished leather, nubuck-like synthetic leather has no silver layer on the surface, so when used in shoes, it has high moisture permeability and no stuffiness, so it is comfortable to wear, but rainwater penetrates very easily There is a serious drawback for shoe leather.
As a method of giving waterproofness to nubuck synthetic leather,
Although various methods have been proposed, for example, a method of applying a waterproof film on the back surface, specifically, a method of transferring a urethane resin film, a vinyl resin film, or the like is generally performed.

[0003]

However, in the prior arts, all of them have only a degree of waterproofness as a material, and the waterproofness when finished in shoemaking is not sufficient. Furthermore, these products were not considered at all in that they do not impair the moisture permeability, which is a characteristic of nubuck, that is, they have almost no moisture permeability, and their comfort is not very good. An object of the present invention is to provide a nubuck synthetic leather having water repellency and waterproofness without impairing moisture permeability.

[0004]

According to the present invention, a fluorine-containing urethane resin and a polyurethane porous layer containing a urethane resin as a main component are laminated on a surface of a fiber substrate to which a fluorine-based surfactant is fixed, and The surface of the porous layer is ground, and a water-in-oil urethane resin emulsion is further applied to the back surface of the fiber base material to form a urethane resin-based porous layer film. It is intended to provide leather.

[0005] The synthetic leather of the present invention comprises at least three layers. That is, a layer of a fiber base material to which a fluorine-based surfactant is fixed (hereinafter, also referred to as a “base cloth layer”)), a fluorinated urethane resin whose surface is ground, and a polyurethane porous layer mainly composed of a urethane resin ( Hereinafter, also referred to as a “fluorine-containing urethane resin nubuck layer”), and a layer of a urethane resin-based porous layer coating formed by applying a water-in-oil type urethane resin emulsion (hereinafter also referred to as a “water-in-oil type urethane resin porous layer”). 3). By constituting a synthetic leather with these three layers, water repellency, waterproofness, and moisture permeability are imparted.

In the present invention, as the fluorine-based surfactant fixed to the fiber base material of the base fabric layer, any commercially available fluorine-based surfactant may be used. For example, Dickguard F-90 [Dainippon Ink Chemical Industry Co., Ltd.], NK
Guard FGN-90 (manufactured by Nichika Chemical Co., Ltd.), Asahi Guard AG310 (Meisei Chemical Co., Ltd.) and the like. Such a fluorinated surfactant imparts a water-repellent effect to the fiber base material, and can prevent permeation of water from perforations or the like when made into shoes. In order to obtain such an effect, the amount of the fixed surfactant is 0.1 to 2.0% by weight, preferably 0.5 to 2.0% by weight, based on the solid content of the fiber base material.
If it is 1.0% by weight and less than 0.1% by weight, a sufficient water repellent effect cannot be obtained, while if it exceeds 2.0% by weight, a coating layer of a water-in-oil type urethane resin emulsion to be processed next. Does not have sufficient adhesive strength.

[0007] In the present invention, as the fiber substrate, cotton,
Natural fibers such as hemp; Regenerated fibers such as rayon; Semi-synthetic fibers such as acetate; Synthetic fibers such as polyamide, polyester, polyacrylonitrile alone or knitted, woven or non-woven fabrics made of blended fibers of these Can be. In addition, it is preferable that at least the surface on which the fluorinated urethane resin nubuck layer is laminated is subjected to a raised or napped process as generally used as a base fabric of synthetic leather. . In addition,
The basis weight of the fiber substrate is usually about 100 to 400 g / m ² , preferably about 200 to 300 g / m ² .

As a method of fixing a fluorine-based surfactant to a fiber base material, the fiber base material may be dipped in an aqueous solution containing a fluorine-based surfactant, then squeezed, and dried. It is preferable to form a fluorinated urethane resin nubuck layer on the surface of the material and then fix it by immersion.
This is because the method does not impair the adhesive strength between the fluorinated urethane resin nubuck layer and the fiber base material. The ground surface of the polyurethane porous layer formed on the surface has water repellency, so that it is hardly wet by this aqueous solution, and only the fiber base material is wet, and a water repellent effect can be obtained.

The content of the fluorinated surfactant in the aqueous solution is 0.1 to 1.0% by weight, preferably 0.2 to 0.4% by weight as a solid content. In this aqueous solution,
In some cases, a water-soluble resin such as a urethane resin or an acrylic resin may be partially blended and used as an auxiliary agent for fixing the fluorine-based surfactant to the fiber base material. In this way,
By sufficiently performing the water-repellent treatment of the fiber base material, it is possible to prevent water from permeating through perforations and the like when nubuck-like synthetic leather, which is the final product, is used as shoes.

Next, the fluorine-containing urethane resin nubuck layer laminated on the surface of the base fabric layer will be described. The main components of this layer are a fluorinated urethane resin and a urethane resin. Examples of the fluorine-containing urethane resin include an addition reaction product of a urethane prepolymer having a terminal isocyanate group and a perfluoroalkyl group-containing compound having an active hydrogen group.

The above urethane prepolymers include polyethylene adipate, polybutylene adipate, poly-ε-
Polyester polyols such as caprolactone, and polyether polyols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and hexamethylene diisocyanate Is obtained by reacting with a polyisocyanate such as isophorone diisocyanate, xylene diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate, and a urethane prepolymer using a polyester polyol, polyether polyol or the like having a molecular weight of 400 to 4,000. Polymers are preferred.

As the perfluoroalkyl group-containing compound having an active hydrogen group to be subjected to an addition reaction with the urethane prepolymer, for example, [Wherein, R ₁ represents a C ₆ -C ₁₂ perfluoroalkyl group and R ₂ represents a C ₁ -C ₃ alkyl group]. The urethane prepolymer and the perfluoroalkyl group-containing compound are:
It is preferable to select and use the molecular weights and types of the urethane prepolymer and the perfluoroalkyl group-containing compound so that the fluorine content in the fluorine-containing urethane resin obtained by the reaction between the two becomes 12 to 35% by weight.

As the urethane resin, urethane resins generally used for wet synthetic leather can be used. For example, those obtained from the following polyols and polyisocyanates can be mentioned. That is, as the polyol, polyethylene adipate, polyethylene butylene adipate, polybutylene adipate, polyester polyols such as poly-ε-caprolactone, polypropylene glycol, polyether polyols such as polytetramethylene ether glycol, or ethylene glycol, 1,4-butane Examples thereof include low molecular weight glycols such as diols and 1,3-butanediol, and polycarbonate polyols.

Further, as the polyisocyanate, 4,
4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hexamethylene diisocyanate, xylene diisocyanate, 4,4'-dicyclohexyl methane diisocyanate, and the like.
Diphenylmethane diisocyanate is preferred.

The proportion of the fluorinated urethane resin is preferably 0.1 to 5.0% by weight, more preferably 0.5 to 2.0% by weight, based on the total amount of the fluorinated urethane resin and the urethane resin. It is. When the content of the fluorine-containing urethane resin is less than 0.1% by weight, the water repellency of the surface of the fluorinated urethane resin nubuck layer is insufficient, which is not preferable. On the other hand, when the content exceeds 5.0% by weight, the water and oil repellency of the surface of the nubuck layer is poor. Too strong, when used as a shoe material,
The problem that the adhesive becomes difficult to adhere is likely to occur. In the fluorinated urethane resin and urethane resin,
If necessary, film forming aids, coloring agents, fillers, light stabilizers,
Various additives such as an ultraviolet absorber, an antioxidant, and a flame retardant can be mixed.

In the present invention, the polyurethane porous layer is a porous layer, which is obtained by applying a urethane resin solution to a fiber base material and performing wet coagulation. That is, a urethane resin solution (hereinafter also referred to as "urethane resin liquid") obtained by dissolving a mixture of a fluorine-containing urethane resin, a urethane resin, and, if necessary, a surfactant, a stabilizer, a solvent, a colorant, and the like in a solvent is used as a fiber base. After being applied to the surface of the material, it is immersed in a non-solvent coagulation tank of polyurethane (fluorine-containing urethane resin and urethane resin) to solidify the surface, and then completely desolvated in a washing tank and dried.
A wet porous layer of polyurethane is formed on the fiber substrate.

As a solvent for the polyurethane, an organic solvent such as dimethylformamide, dimethylacetamide, dimethylsulfoxide and tetrahydrofuran can be used. Urethane resin liquid is applied by knife coater,
It can be performed by a reverse roll coater or the like.
The application amount of the urethane resin liquid is 10 to 200% by weight, preferably about 20 to 100% by weight, in terms of the urethane resin liquid solids per fiber substrate weight.

As the non-solvent for the polyurethane, for example, water or a mixed solvent of water and dimethylformamide can be used. The treatment with such a non-solvent is performed, for example, by placing a fiber base material coated with a urethane resin liquid in water at 15 to 60 ° C.
It can be carried out by immersion for up to 60 minutes. Further, washing can be repeated in warm water to remove the solvent, followed by dehydration and drying to form a polyurethane porous film on the fiber base material. The surface of the polyurethane porous layer obtained in this manner is further uniformly ground to give a nubuck tone of natural leather.

Grinding is performed uniformly with a buffing machine equipped with, for example, emery paper having a particle size of # 100 to # 400 mesh so that the nubuck appearance of natural leather is exhibited. Although the particle size of the emery paper is not particularly limited, in general, if it is less than # 100, it is difficult to obtain a smooth surface because it is too coarse, while if it exceeds # 400, it is too fine and the surface of the polyurethane porous layer is ground. In this case, the resistance of the surface becomes too large and the work becomes difficult, which is not preferable. Such grinding may be carried out immediately after the formation of the polyurethane porous layer on the surface of the fiber base material, or finally, three layers of the polyurethane porous layer, the base cloth layer, and the water-in-oil urethane resin porous layer. May be performed after the formation.

Next, the back surface of the nubuck leather, that is, the water-in-oil type urethane resin porous layer will be described. On the back surface of the base fabric layer, a water-in-oil type urethane resin emulsion is applied, gelled by heating, and dried to form a porous layer coating. Examples of the water-in-oil urethane resin emulsion include Heimulen 3040 (manufactured by Dainichi Seika Kogyo Co., Ltd.) and Soltex PX
-100 (manufactured by Dainippon Ink and Chemicals, Inc.). As a method for applying the water-in-oil type urethane resin emulsion, a knife coater, a reverse roll coater, or the like can be used. The coating amount of the water-in-oil type urethane resin emulsion is 5 to 5 in terms of the urethane resin liquid solid content per fiber base weight.
0% by weight, preferably 10 to 20% by weight. Heating is usually performed using a hot air circulation type drying oven.

The water-in-oil type urethane resin porous layer contributes to waterproofness and moisture permeability, and the waterproof effect must be enhanced without impairing the moisture permeability. However, there are some which have sufficient moisture permeability but poor waterproofness. In some cases, it is preferable to apply a water-in-oil type urethane resin emulsion in which the ratio of water to the solvent is changed, in a multiple coat. In this case, it is preferable to first apply a material having a large ratio of water, that is, a material having a large porosity, and then to apply a material having a high solvent ratio, that is, a material having a low porosity.

Although the method of forming the individual layers of the nubuck tone synthetic leather of the present invention has been described, it is preferable that the manufacturing process be performed as follows. First, after a urethane resin liquid is applied to the surface of the fiber base material, it is immersed in a non-solvent of polyurethane to coagulate, desolventized and dried to form a microporous polyurethane layer. The surface of the thus obtained microporous polyurethane layer is uniformly ground with a buffing machine to exhibit the nubuck appearance of natural leather.

Next, this nubuck leather is immersed in an aqueous solution containing a fluorine-based surfactant, and then squeezed and dried. A water-in-oil type urethane resin emulsion is applied to the back surface of the base fabric layer of the synthetic leather obtained by processing in this manner, and the surface is obtained in a nubuck tone, and then heated and gelled and dried to form a urethane resin-based porous layer coating. Is formed. Other than such a process, after forming a porous layer on both sides of the base fabric layer, the surface may be ground at the final stage to give a nubuck appearance, and the present invention is not limited to the above process.

[0024]

In the present invention, the fluorinated urethane resin nubuck layer formed on the surface of the fiber base material by a wet method has a water repellency due to the inclusion of fluorine. Further, a fluorine-based surfactant is fixed to the fiber base material, and has water repellency and waterproofness. Even when used as a shoe material, rainwater does not permeate through perforations. Further, since a waterproof and moisture-permeable water-in-oil urethane resin porous layer is formed on the back surface of the fiber layer, it is possible to obtain a nubuck-like synthetic leather having very good waterproofness and excellent moisture permeability.

[0025]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In addition, in an Example, a part represents a weight part. Example 1 A urethane resin solution having the following composition was prepared. Formulation Rezamin CU4310 [manufactured by Dainichi Seika Kogyo Co., Ltd.]; (urethane resin solid content: 30%) 100 parts dimethylformamide; 100 parts fluorinated urethane resin [manufactured by Dainippon Ink and Chemicals, Chris Bon Assister FX -3D, urethane resin solid content 60%]; 1 part anionic surfactant [Sanmorin OT-70, manufactured by Sanyo Chemical Industries, Ltd.]; 4 parts nonionic surfactant [Nonion OP, manufactured by NOF Corporation] -80R]; 1 part Silicone foam stabilizer (manufactured by Toray Dow Corning Silicone Co., Ltd., SH8400); 0.5 part Pigment; 10 parts

Next, a 0.7 mm thick single-sided raised cloth made by blending polyester fibers and rayon fibers and woven into a twill weave was prepared by using water / dimethylformamide (weight ratio) =
After being immersed and squeezed in a 100/10 aqueous solution, 900 g / m ² of the urethane resin solution was applied to the raised surface. Then, 5% dimethylformamide 10% aqueous solution
The coating layer was immersed for 5 minutes, solidified initially, and then squeezed several times with a washing layer of 50 ° C. warm water to completely remove the solvent from the coating layer. Drying was performed in a heat circulating oven at 100 ° C. to 130 ° C. for 5 minutes.

Next, the surface of the thus obtained polyurethane microporous layer was pre-buffed with # 120 mesh emery paper and then finished with # 360 mesh emery paper. The fibrous base material on which the fluorine-containing urethane resin nubuck layer thus obtained was laminated on the surface was immersed in an aqueous solution having the following formulation to fix the fluorine-based surfactant to form a base fabric layer. .

Formulation water; 100 parts Fluorinated surfactant [Dickguard F-90 manufactured by Dainippon Ink and Chemicals, Inc.]; 2 parts Water-soluble urethane resin [Dainippon Ink and Chemicals, Inc .; Hydran 111]; 10 parts The squeezing ratio at this time is 120%, and drying is 100 to 1
This was performed in a hot air circulation oven at 30 ° C. for 5 minutes.

A water-in-oil type urethane resin emulsion was applied to the back surface of the base fabric layer thus formed, and dried to form a water-in-oil type urethane resin porous layer. The application was performed in two times. That is, first, 300 g / m ^{2 of the} undercoating mixture shown below is applied and dried in a hot air circulation oven at 100 ° C. to 130 ° C. for 2 minutes, and then the above-described undercoating mixture at 100 g / m ^{2 is} placed thereon. ² coats, 100 ℃
It was dried for 2 minutes in a hot air circulating oven at １３０130 ° C.

Hydraulic water-in-oil type urethane resin emulsion Heimulen X3040 [urethane resin manufactured by Dainichi Seika Kogyo Co., Ltd.]; 100 parts methyl ethyl ketone; 7 parts xylene; 28 parts pigment; 5 parts water; 40 parts methyl ethyl ketone; 5 parts Silicone foam stabilizer [Resamine UM810 manufactured by Dainichi Seika Kogyo Co., Ltd.]; 2 parts Isocyanate crosslinking agent [Nihon Polyurethane Industry Co., Ltd., Coronate L]; 2 parts

Water-in-oil urethane resin emulsion Heimulen Y229 (urethane resin manufactured by Dainichi Seika Kogyo Co., Ltd.); 100 parts methyl ethyl ketone; 100 parts pigment; 3 parts water; 40 parts methyl ethyl ketone; 5 parts silicone foam stabilizer [manufactured by Dainichiseika Color & Chemicals Mfg. Co., Resamine UM810]; 2 parts resulting synthetic leather, water pressure resistance 2,000MmH ₂ O or more, moisture permeability 3,300 g / m ^2/24 hours, water repellency 80
And was excellent.

[0032]

According to the present invention, it is possible to obtain nubuck-like synthetic leather having improved water repellency and waterproofness, which are the drawbacks of nubuck-like leather, and excellent in moisture permeability. It is possible to manufacture shoes with no penetration and excellent comfort without stuffiness.

Claims (1)

(57) [Claims] 1. A polyurethane porous layer comprising a fluorine-containing urethane resin and a urethane resin as a main component is laminated on a surface of a fiber base material to which a fluorine-based surfactant is fixed, and the surface of the porous layer is ground, Further, a water-repellent, waterproof, and moisture-permeable nubuck-like synthetic leather in which a water-in-oil urethane resin emulsion is applied to the back surface of the fiber base material to form a urethane resin-based porous layer coating.