JP2014065983A - Synthetic leather and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide synthetic leather which has a mat effect and soft touch texture, and also does not cause a darkening phenomenon even under an ultraviolet exposure environment, and to provide a method for manufacturing the same.SOLUTION: The synthetic leather is formed by sequentially stacking a fibrous substrate, a skin layer made of a polyurethane resin and a surface treatment layer made of a polyurethane resin. The surface treatment layer contains a matting agent and/or a touch sense improving agent and a light fastness improving agent.

Description

  The present invention relates to synthetic leather and a method for producing the same.

  Synthetic leather is widely applied in various fields such as bags, clothing, shoes, chairs and vehicle seats. In general, synthetic leather is coated with a heat-melt resin or solvent-type resin on a release paper and dried to form a film, and then the film and substrate are bonded together, and then bonded by thermocompression bonding. Manufactured by peeling the pattern.

By the way, in recent years, a matting agent or a tactile sensation improving agent is added to a resin constituting the synthetic leather to give a visual change or a tactile change to the surface of the synthetic leather. (Patent Document 1).
However, when the polyurethane resin of the surface treatment layer is decomposed due to aging deterioration due to ultraviolet exposure and the volume is reduced, a matting agent and a tactile sensation improver that are not easily affected by ultraviolet rays are exposed to the surface, and a darkening phenomenon occurs.

Japanese Patent Application Laid-Open No. 08-1843

  An object of the present invention is to provide a synthetic leather that has a matte effect and a soft touch feeling even in an environment exposed to ultraviolet rays and does not cause darkening, and a method for producing the same.

  The synthetic leather according to the present invention is a synthetic leather obtained by sequentially laminating a fibrous base material, a skin layer made of polyurethane resin, and a surface treatment layer made of polyurethane resin, and a matting agent is applied to the surface treatment layer. And / or a tactile sensation improver and a light fastness improver.

In addition, the method for producing a synthetic leather according to the present invention includes:
Applying a skin layer resin liquid on a releasable substrate to form a skin layer made of polyurethane resin;
Bonding the skin layer and the fibrous base material;
Removing the releasable substrate;
And a step of applying a surface treatment layer resin solution containing a matting agent and / or a tactile sensation improver and a light resistance improver on the skin layer to form a surface treatment layer made of a polyurethane resin.

  ADVANTAGE OF THE INVENTION According to this invention, even in the environment where an ultraviolet-ray is exposed, the synthetic leather which has a matte effect and a soft touch feeling, and does not produce a darkening phenomenon can be obtained.

The synthetic leather according to the present invention is a synthetic leather obtained by sequentially laminating a fibrous base material, a skin layer made of polyurethane resin, and a surface treatment layer made of polyurethane resin, and a matting agent is applied to the surface treatment layer. And / or a synthetic leather comprising a tactile sensation improving agent and a light resistance improving agent.

  The fibrous base material used in the present invention is not particularly limited, and examples thereof include fiber fabrics such as woven fabrics, knitted fabrics, and non-woven fabrics, and natural leather (including floor leather). That's fine. Further, a known non-solvent, solvent-based or water-based polymer compound, preferably a polyurethane resin or a copolymer thereof, or a mixture mainly composed of a polyurethane resin is coated or impregnated on a fiber fabric, and dry coagulation or What was solidified by wet coagulation can also be used. The type of fiber in the fiber fabric is not particularly limited, and examples thereof include known fibers such as natural fibers, regenerated fibers, semi-synthetic fibers, and synthetic fibers, and two or more of these may be combined. Of these, a knitted fabric made of synthetic fiber, particularly a knitted fabric made of polyester fiber is preferably used from the viewpoint of strength and workability.

  In the synthetic leather according to the present invention, a skin layer made of polyurethane resin is used as a first resin layer on one surface of the above-mentioned fibrous base material, and a matting agent and / or a tactile sensation is improved as a second resin layer. A surface treatment layer made of a polyurethane resin containing an agent and a light resistance improver is laminated.

  First, the skin layer will be described.

  The polyurethane resin constituting the skin layer is not particularly limited, and a conventionally known polyurethane resin can be used. For example, a polyether-type polyurethane resin, a polyester-type polyurethane resin, a polycarbonate-type polyurethane resin, etc. can be mentioned, These can be used individually by 1 type or in combination of 2 or more types. Of these, polycarbonate polyurethane resins are preferable from the viewpoint of wear resistance, and polyether polyurethane resins are preferable from the viewpoint of texture. The form of the polyurethane resin can be used regardless of whether it is a hot melt system, a solvent system, an aqueous system, or a one-component type or a two-component curable type, and is appropriately selected depending on the purpose and application. That's fine.

  For the polyurethane resin, known additives such as a heat stabilizer, a thermoplastic resin, a thermosetting resin, a pigment, a flame retardant, a conductivity-imparting agent, an antistatic agent, a moisture permeability improver, a repellent agent, and the like are added. A water agent, an oil repellent agent, a water absorbing agent, a moisture absorbing agent, a deodorant, an antifoaming agent, a pigment dispersant, a hydrolysis inhibitor, a crosslinking agent, a thickener and the like may be contained.

  The thickness of the skin layer is preferably 5 to 100 μm, and more preferably 20 to 50 μm. If the thickness is less than 5 μm, it becomes difficult to form a uniform resin layer, and the skin layer is partially lost, so that sufficient wear resistance may not be obtained. If the thickness exceeds 100 μm, the texture may become coarse.

  The above-described skin layer is laminated on one surface of the fibrous base material. When laminating, an adhesive layer may be interposed, or direct lamination may be performed. Through the adhesive layer, excessive penetration of the polyurethane resin constituting the skin layer into the fibrous base material, which may occur when the skin layer is directly laminated on the fibrous base material, or unevenness in the skin layer As a result, natural leather-like feel and texture can be provided.

  The synthetic leather of the present invention has a matting agent and / or a tactile sensation improver and a light resistance improvement as a second resin layer on the surface of a skin layer made of a polyurethane resin laminated on one side of a fibrous base material. A surface treatment layer made of a polyurethane resin containing an agent is laminated. Thereby, the aged deterioration of the polyurethane resin is suppressed, the matting agent and the tactile sensation improving agent on the surface of the synthetic leather are not exposed, and the color change in the dark color direction, that is, the darkening is eliminated. In the present invention, the surface treatment layer is a general term for the outermost resin layer formed on the surface side of the skin layer and protecting the skin layer, and is composed of at least one resin layer, but has the same or different composition. It may be a resin layer of more than one layer.

  The polyurethane resin used for forming the surface treatment layer is not particularly limited, and examples thereof include a polyether-based polyurethane resin, a polyester-based polyurethane resin, a polycarbonate-based polyurethane resin, and the like. Two or more types can be used in combination. Of these, polycarbonate-based polyurethane resins are preferred from the viewpoint of wear resistance and light fastness. In addition, the form of the polyurethane resin can be used regardless of whether it is solventless, hot-melt, solvent-based, or water-based, and it can be used regardless of one-pack type or two-pack curable type, depending on its purpose and application. What is necessary is just to select suitably.

  The content (solid content) of the light resistance improver in the surface treatment layer is preferably 1 to 10% by weight, and more preferably 3 to 8% by weight. When the content of the light resistance improver is less than 1% by weight, deterioration of the polyurethane resin over time cannot be suppressed, and blackening may occur. If the content of the light resistance improver exceeds 10% by weight, the film strength of the synthetic leather may be impaired.

  Specific examples of the light resistance improver used in the present invention include benzotriazole, benzophenone, triazine, cyanoacrylate, oxanilide, salicylate, formamidine, carbazide, benzoate, nickel complex, A hindered amine system, a cinnamic acid ester system, etc. are mentioned, These can be used individually by 1 type or in combination of 2 or more types. Among them, a benzotriazole light resistance improver is preferably used from the viewpoint of good heat resistance and dispersibility in a polyurethane resin.

  The matting agent used in the present invention is not particularly limited, and a known matting agent can be used. Examples thereof include inorganic beads such as wax and silica beads, resin beads such as acrylic, and the like, and these can be used alone or in combination of two or more. Among these, silica beads are preferably used from the viewpoint of versatility.

  The tactile sensation improver used in the present invention is not particularly limited, and a known tactile sensation improver can be used. Examples thereof include resin beads such as urethane beads, collagen powder, leather powder, gelatin powder and the like, and these can be used alone or in combination of two or more. Of these, urethane beads are preferably used from the viewpoint of touch.

  For the polyurethane resin of the surface treatment layer, if necessary, in addition to the matting agent, the tactile sensation improver, and the light resistance improver, a heat stabilizer, a thermoplastic resin, Curable resin, pigment, flame retardant, conductivity imparting agent, antistatic agent, moisture permeability improver, water repellent, oil repellent, water absorbent, moisture absorbent, deodorant, defoamer, pigment dispersant, hydrolysis Arbitrary components, such as an inhibitor, a crosslinking agent, and a thickener, can be used singly or in combination of two or more.

  The thickness of the surface treatment layer is preferably 3 to 30 μm, and more preferably 5 to 15 μm. If the thickness is less than 3 μm, it is difficult to form a uniform resin layer, and the surface treatment layer may be partially lost, so that sufficient wear resistance may not be obtained. If the thickness exceeds 30 μm, the texture may become rough or whitening may occur.

Next, the manufacturing method of the synthetic leather which concerns on this invention is demonstrated. The manufacturing method is as follows:
(1) A step of applying a skin layer resin liquid on a releasable substrate to form a skin layer made of a polyurethane resin,
(2) A step of bonding the skin layer and the fibrous base material,
(3) a step of peeling the releasable substrate;
(4) A step of applying a surface treatment layer resin solution containing a matting agent and / or a tactile sensation improver and a light resistance improver onto the skin layer to form a surface treatment layer made of a polyurethane resin,
Is included.

  As a method for applying the skin layer resin solution on the releasable substrate, various conventionally known methods can be employed, and the method is not particularly limited. For example, the method using apparatuses, such as a reverse roll coater, a spray coater, a roll coater, a knife coater, a comma coater, can be mentioned. In particular, coating with a reverse roll coater, knife coater, or comma coater is preferable because a uniform thin film layer can be formed.

  The releasable base material used in the present invention is not particularly limited, and may be a base material having releasability with respect to a polyurethane resin or a base material subjected to a release treatment. For example, release paper And a release treatment cloth, a water repellent treatment cloth, an olefin sheet or film made of polyethylene resin or polypropylene resin, a fluororesin sheet or film, a plastic film with release paper, and the like. The releasable base material may have a concavo-convex pattern, and by using such a releasable base material, design properties can be imparted to the surface of the synthetic leather.

  The coating thickness of the skin layer resin solution is preferably 25 to 700 μm, and more preferably 100 to 350 μm. By setting the coating thickness within this range, a skin layer having a thickness of preferably 5 to 100 μm, more preferably 20 to 50 μm is obtained.

After apply | coating the resin liquid for skin layers to a mold release base material, it heat-processes as needed. The heat treatment is performed by evaporating the solvent in the resin liquid for the skin layer, drying the resin, and using a cross-linking agent that causes a cross-linking reaction by the heat treatment or when using a two-component curable resin. This is done to promote and form a film with sufficient strength.
It is preferable that the heat processing temperature is 50-150 degreeC, More preferably, it is 60-120 degreeC. If the heat treatment temperature is less than 50 ° C., the heat treatment takes time, and there is a possibility that the process load becomes large or the crosslinking of the resin is insufficient and the wear resistance becomes poor. If the heat treatment temperature exceeds 150 ° C., the texture of the synthetic leather may become rough. The heat treatment time is preferably 2 to 20 minutes, more preferably 2 to 10 minutes. If the heat treatment time is less than 2 minutes, the resin may be insufficiently crosslinked, resulting in poor wear resistance. If the heat treatment time exceeds 20 minutes, the processing speed may become slow and the process load may increase.

  Next, the skin layer and the fibrous base material are bonded together. It may be through an adhesive layer or may be laminated directly. Through the adhesive layer, excessive penetration of the polyurethane resin constituting the skin layer into the fibrous base material, which may occur when the skin layer is directly laminated on the fibrous base material, or unevenness in the skin layer As a result, natural leather-like feel and texture can be provided.

  A polyurethane resin is preferably used as the adhesive. Resins similar to those used for the skin layer can be used.

  The method for applying the adhesive may be any of various known methods and is not particularly limited. For example, the method using apparatuses, such as a reverse roll coater, a spray coater, a roll coater, a gravure coater, a kiss roll coater, a knife coater, a comma coater, can be mentioned.

  Next, the releasable substrate is peeled off, and a skin layer is formed on the fibrous substrate. A surface treatment layer made of a polyurethane resin is formed on the skin layer.

  As a method of applying the surface treatment layer resin liquid to the skin layer in order to form the surface treatment layer, various conventionally known methods can be employed and are not particularly limited. For example, the method using apparatuses, such as a reverse roll coater, a spray coater, a roll coater, a gravure coater, a kiss roll coater, a knife coater, a comma coater, can be mentioned. Especially, the application | coating by a reverse roll coater, a knife coater, or a comma coater is preferable at the point that formation of a uniform thin film layer is possible. What is necessary is just to set the application | coating thickness of a resin composition suitably according to the thickness of the said surface treatment layer.

Next, heat treatment is performed as necessary. The heat treatment is performed by evaporating the solvent in the resin liquid for the surface treatment layer, drying the resin, and using a crosslinking agent that causes a crosslinking reaction by the heat treatment, or when using a two-component curable resin. Is performed to form a film having sufficient strength.
It is preferable that the heat processing temperature is 50-150 degreeC, More preferably, it is 60-120 degreeC. If the heat treatment temperature is less than 50 ° C., the heat treatment takes time, and there is a possibility that the process load becomes large or the crosslinking of the resin is insufficient and the wear resistance becomes poor. If the heat treatment temperature exceeds 150 ° C., the texture of the synthetic leather may become rough. The heat treatment time is preferably 2 to 20 minutes, more preferably 2 to 10 minutes. If the heat treatment time is less than 2 minutes, the resin may be insufficiently crosslinked, resulting in poor wear resistance. If the heat treatment time exceeds 20 minutes, the processing speed may become slow and the process load may increase.

  Thereby, the synthetic leather of this invention can be obtained.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example. “Parts” in the examples are based on weight. Moreover, the following methods evaluated the obtained synthetic leather.

(1) Light fastness Light fast fast equipped with a xenon lamp (water-cooled 6.5 kW) with a test piece cut to a width of 65 mm and a length of 150 mm superimposed on a 10 mm thick slab urethane foam. Using a Ci35W type (manufactured by Atlas Co., Ltd.), the test was performed under the following conditions.
Light cycle Dark cycle Total irradiation amount 750 kJ / m ² −
Illuminance intensity 0.55 W / m ^2-
Black panel temperature 89 ± 3 ℃ 38 ± 3 ℃
Relative humidity 50 ± 5% 95 ± 5%
Cycle time 3.8 hr 1.0 hr
The specimens before and after the irradiation are visually observed, and the specimens after the irradiation are graded using the JIS L-0804 standard gray scale, and the discoloration grade 4 or more and fading grade 3 or more are passed. did.

(2) Darkening phenomenon The specimen after the light resistance test was visually observed to check for the presence of darkening.
When darkening was not seen, it passed, and when darkening was seen, it was rejected.

[Example 1]
A polyurethane resin solution for a skin layer was prepared by adding 40 parts by weight of dimethylformamide to 100 parts by weight of a polycarbonate-based polyurethane resin (named Chris Bon NY-328, manufactured by DIC Corporation) and adjusting the viscosity to about 2000 cps. The polyurethane resin solution was coated on a release paper so as to have a coating thickness of 200 μm, and then dried at 130 ° C. for 2 minutes to obtain a skin layer made of a polyurethane resin.

Next, an adhesive resin solution adjusted to a viscosity of about 4500 cps by adding 50 parts by weight of dimethylformamide to 100 parts by weight of a polycarbonate-based polyurethane adhesive (named Crisbon TA-205, manufactured by DIC Corporation) is applied to the skin layer. After coating with a reverse roll coater to a coating thickness of 200 μm, the coating is dried at 100 ° C. for 1 minute. The adhesive coated surface and the tricot knitted fabric were combined and press-bonded under pressure of 4 kgf / cm ² for 1 minute to obtain a laminate having a skin layer made of polyurethane resin having a thickness of 40 μm.

A polyurethane resin solution for a surface treatment layer adjusted to a viscosity of about 2000 cps was prepared in accordance with Formula 1 described below. The polyurethane resin liquid was coated on the skin layer with a reverse roll coater so that the coating amount was 50 g / m ^2, and then dried at 130 ° C. for 2 minutes to form a surface treatment layer having a thickness of 15 μm. Synthetic leather was obtained.

“Prescription 1”
WF-13447 40 parts by weight (silica-containing polyurethane resin, solid content 40%, manufactured by Star Co., Ltd.)
RU-40-350 60 parts by weight (polyurethane resin, solid content 40%, manufactured by Star Co., Ltd.)
Dynamic beads UCN-5070D 8 parts by weight (urethane beads, solid content 100%, manufactured by Dainichi Seika Kogyo Co., Ltd.)
EX-9345 5 parts by weight (crosslinking agent, solid content 50%, manufactured by Star Co., Ltd.)
X parts by weight of water

The light fastness to light of the obtained synthetic leather was a grade 4 fading and the darkening phenomenon was a pass.

[Comparative Example 1]
A synthetic leather was obtained in the same manner as in Example 1 except that no light resistance improver was added to the surface treatment layer.
The light fastness to light of the synthetic leather thus obtained was disqualified in the color change grade 3-4, and the darkening phenomenon was rejected.

Claims (2)

  A synthetic leather obtained by sequentially laminating a fibrous base material, a skin layer made of polyurethane resin, and a surface treatment layer made of polyurethane resin. The surface treatment layer has a matting agent and / or a tactile sensation improver and light resistance. Synthetic leather comprising an improver. Applying a skin layer resin liquid on a releasable substrate to form a skin layer made of polyurethane resin;
Bonding the skin layer and the fibrous base material;
Removing the releasable substrate;
And a step of applying a surface treatment layer resin solution containing a matting agent and / or a tactile sensation improver and a light resistance improver on the skin layer to form a surface treatment layer made of a polyurethane resin. A method of manufacturing leather.