阅读说明：本技术 车辆内饰用真皮制品 (Leather product for vehicle interior ) 是由 松田兴吉 斋藤康纪 于 2020-02-03 设计创作，主要内容包括：本发明为车辆内饰用真皮制品。提供一种形成有凹凸图案的车辆内饰用真皮制品。一种车辆内饰用真皮制品,其具备真皮基材和层叠在所述真皮基材上的整饰层,在所述真皮制品的正面具有凹凸图案,所述整饰层的厚度为2～10μm。(The present invention relates to a genuine leather product for vehicle interior. Provided is a genuine leather product for vehicle interior decoration, which is formed with a concavo-convex pattern. A genuine leather product for vehicle interior decoration comprises a genuine leather base material and a finishing layer laminated on the genuine leather base material, wherein the genuine leather product has a concave-convex pattern on the front surface, and the thickness of the finishing layer is 2-10 μm.)

1. A genuine leather product for vehicle interior decoration comprises a genuine leather base material and a finishing layer laminated on the genuine leather base material,

the front surface of the genuine leather product is provided with a concave-convex pattern,

the thickness of the finishing layer is 2-10 mu m.

2. The genuine leather product for vehicle interior trim according to claim 1, wherein the wear resistance of the front surface measured according to JIS L10968.19.3C method (taber method) is class 4 or more.

3. The genuine leather product for vehicle interior trim according to claim 1 or 2, wherein the concave-convex pattern is a concave-convex pattern having a concave-convex pattern depth of 1000 μm or more.

4. The genuine leather product for vehicle interior trim according to any one of claims 1 to 3, wherein the finishing layer comprises: a primer layer formed on the surface of the dermal base material; and an outermost layer laminated on the undercoat layer.

5. The genuine leather product for vehicle interior finishing according to any one of claims 1 to 4, wherein the development rate of the finishing layer is 110% or more.

6. The genuine leather product for vehicle interior trim according to any one of claims 1 to 5, wherein the finishing layer has an outermost layer formed of a composition comprising an acrylic resin and/or a urethane resin, a silicone rubber, and a crosslinking agent.

7. The genuine leather product for vehicle interior trim according to claim 6, wherein the elastic modulus of the rubber elastic coating of the silicone rubber is 0.001 to 0.5 MPa.

8. The genuine leather product for vehicle interior trim according to claim 6 or 7, wherein the acrylic resin comprises a fluorine-modified acrylic resin, and the urethane resin comprises at least 1 selected from the group consisting of a polycarbonate-based polyurethane resin and a polyether-based polyurethane resin.

9. The genuine leather product for vehicle interior trim according to any one of claims 6 to 8, wherein the crosslinking agent comprises an isocyanate-based crosslinking agent.

10. The genuine leather product for vehicle interior trim according to any one of claims 1 to 9, wherein the genuine leather substrate is a non-buffed genuine leather.

Technical Field

The present invention relates to a genuine leather product for vehicle interior.

Background

Genuine leather products are used in various fields such as clothing, bags, shoes, interior materials, and vehicle interior materials due to unique texture and high-grade texture such as appearance (gloss, texture, etc.), hand, touch (softness, elasticity, swelling, smoothness, etc.). A genuine leather product used for vehicle interior applications is expected to be used for a long period of time, and therefore, high durability, particularly wear resistance, is required.

In order to improve the abrasion resistance of a genuine leather product, a resin coating (finishing layer) may be formed on the surface of the genuine leather substrate. For example, patent document 1 discloses a natural leather in which a foamed layer having a concave-convex pattern and a thickness of 50 to 350 μm, which is formed of a polyurethane resin, is laminated on a surface of the natural leather, and a protective layer having a thickness of 10 to 100 μm is further laminated on a surface of the natural leather. The resin film thus formed has a large thickness, and a concave-convex pattern having a shallow leather grain pattern can be formed.

However, the following problems have been clearly found: when a deep uneven pattern is to be formed, the resin film cracks in the recessed portions, and the genuine leather base material may also crack together with the resin film, and thus the shape-forming may not be possible. Namely, the following problems are present: since the resin film is cracked, a deep uneven pattern cannot be formed.

Disclosure of Invention

Problems to be solved by the invention

An object of an embodiment of the present invention is to provide a genuine leather product for vehicle interior trim formed with a concave-convex pattern.

Means for solving the problems

The genuine leather product for vehicle interior decoration according to the embodiment of the present invention comprises a genuine leather base material and a finishing layer laminated on the genuine leather base material, wherein the genuine leather product has a concave-convex pattern on the front surface, and the thickness of the finishing layer is 2 to 10 μm.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present embodiment, a genuine leather product for vehicle interior trim in which a concave-convex pattern is formed can be provided.

Drawings

Fig. 1 is a schematic cross-sectional view of a genuine leather product for vehicle interior trim according to an embodiment.

Fig. 2 is a photograph showing the design of the mold used in the examples.

Fig. 3 is a photograph of a cross section of the genuine leather product for vehicle interior trim of example 1.

Fig. 4 is a photograph of a cross section of the genuine leather product for vehicle interior trim of comparative example 1.

Description of the reference numerals

1 … genuine leather product for vehicle interior, 2 … genuine leather substrate, 3 … finishing layer, 31 … primer layer, 32 … outermost layer, 4 … front face

Detailed Description

The genuine leather product for vehicle interior trim (hereinafter, sometimes simply referred to as "genuine leather product") according to the present embodiment is obtained by laminating a finishing layer on a genuine leather base material. The thickness of the finishing layer is 2 to 10 μm. The front surface of the genuine leather product has a concave-convex pattern.

Fig. 1 is a view schematically showing a cross-sectional structure of a genuine leather product for vehicle interior trim 1 according to an embodiment. In the illustrated example, the genuine leather product 1 includes the finishing layer 3 including the primer layer 31 and the outermost layer 32, and the outermost layer 32 is sequentially laminated on the genuine leather base 2 via the primer layer 31. The surface of the finishing layer 3 is a front surface 4, and the front surface 4 is formed with a concave-convex pattern. In this example, the uneven pattern is formed so as to reach the genuine leather base material 2 and the primer layer 31.

The uneven pattern on the front surface preferably has an uneven pattern depth of 1000 μm or more, more preferably 1200 to 2500 μm. By setting the depth of the concave-convex pattern to 1000 μm or more, a deep concave-convex pattern can be formed.

Here, the depth of the uneven pattern refers to a height difference between the convex portion and the concave portion of the uneven pattern, that is, a height difference between the apex of the convex portion and the bottom of the concave portion (see "D" in fig. 1), and is a value measured in accordance with ISO 5178. Specifically, the surface shape of the dermal product was measured using an OneShot 3D shape measuring instrument (VR-3200, manufactured by KEYENCE CORPORATION). At this time, measurement was performed in a field of view into which a pattern (embossed pattern) of 3 uneven patterns entered, and image processing was performed. Then, a parameter Sz of the surface roughness (maximum height — "maximum mountain height" - "maximum valley depth") is measured in the range after the image processing, and this Sz is used as the depth of the uneven pattern.

The shape of the uneven pattern is not particularly limited, and examples thereof include a conical shape, a truncated cone shape, a columnar shape, a hemispherical shape, a shape imitating a leather art (e.g., a knitting process), characters, and the like. Here, the hand knitting means that long leather is knitted (mesh knitting).

The wear resistance of the front surface of the genuine leather product of the present embodiment measured according to JIS L10968.19.3C method (taber method) is preferably of level 4 or more. By setting the wear resistance of the front surface to 4 or more, a genuine leather product for vehicle interior trim having wear resistance suitable for use as a vehicle interior trim material can be obtained. The abrasion resistance was evaluated based on the surface state after the observation by JISL10968.19.3C method (taber method) and according to the criteria described later.

In the present embodiment, the dermal base material (including double-layered leather) is not particularly limited, and examples of the raw material include those derived from mammals such as cows, horses, pigs, goats, sheep, deer, kangaroos, birds such as ostriches, and reptiles such as turtles, exendins, pythons, and crocodiles. Among them, cowhide having high versatility and large area is preferable. The raw hide itself, dried or salt-pickled and preserved hide is referred to as raw hide, and the raw hide is subjected to a tanning process.

A substance that tannes the skin (hide) of an animal to impart durability (heat resistance, putrefaction resistance, chemical resistance, etc.) and exhibits leathery is called "dermis" (also simply referred to as "leather") to be distinguished from an untanned "skin".

The tanning process is generally roughly divided into a tanning process, a dyeing process and a finishing process, and is further divided into the following steps.

Tanning process: raw leather, soaking, splitting, fleshing, unhairing, liming, splitting, reliming, deliming, softening with enzyme, pickling and tanning.

A dyeing procedure: wringing, screening, shaving, retanning, dyeing, fatliquoring, setting out, drying, rewetting, staking (rubbing, knocking), drying on a veneer, buffing.

A finishing process: coating, back spraying, ironing, die pressing and polishing.

Although the respective steps are improved, the steps are technically almost fixed and are well known in the art. Of course, the sequence may be partially changed, omitted, performed a plurality of times, or replaced with another step.

Before coating, buffing is usually carried out. Buffing is a process for smoothing the surface by shaving off the surface of the grain surface, and homogenizing the surface by removing factors affecting the appearance quality such as individual differences, site differences, moth eating, scratching, skin scars, and the like. In the present embodiment, it is preferable that the buffing is not performed as long as the above-described defects (factors affecting the appearance quality) are not so large in order to exhibit the original design and touch of the animal leather.

In addition, when using the double-layered leather as the genuine leather base, the surface of the double-layered leather is polished before coating for the same reason.

In the present embodiment, a real leather that has been subjected to a patch drying, buffing, or polishing process is used as the real leather base material. In the present specification, the genuine leather subjected to the coating and the shaping of the concave-convex pattern is referred to as a "genuine leather product for vehicle interior trim" or a "genuine leather product" with respect to the genuine leather substrate.

The thickness of the dermal base material (T1, see fig. 1) is not particularly limited, but is preferably 1.0 to 2.0 mm. When the thickness is within the above numerical range, sufficient physical properties and texture can be achieved as a genuine leather product for vehicle interior trim. In the present embodiment, the thickness of the dermal base material can be determined as follows. That is, the dermal base material was divided into 9 regions in trisection in the direction parallel to the back midline (vertical direction) and in 3 trisection in the direction perpendicular to the back midline (horizontal direction), and the thickness of the central portion of each of the 9 regions was measured using a large leather thickness meter, CALATI (manufactured by CALATI), and the average value of these was calculated.

The genuine leather product for vehicle interior trim of the present embodiment is obtained by laminating a finishing layer on the surface of the genuine leather base material.

The finishing layer is a resin layer formed on the genuine leather substrate, and is not limited to a 1-layer structure, and may be 2 or 3 or more layers. The finishing layer has at least an outermost layer, and in the case of a 1-layer structure, the finishing layer comprises only the outermost layer. Here, the outermost layer refers to the layer located outermost, and is the layer forming the front surface of the genuine leather product. The front side of the dermal product refers to: the surface (design surface) of the surface and the back surface of the genuine leather product that is visible to the eye in use.

In one embodiment, the finishing layer may include a primer layer formed on the front surface of the dermal base material, and an outermost layer laminated on the primer layer. The primer layer also forms part of the finish layer. Further, a base coat layer, an intermediate coat layer, and the like (hereinafter collectively referred to as "inner layer") may be provided between the undercoat layer and the outermost layer, and in this case, the inner layer also constitutes a part of the finishing layer.

More specifically, the finishing layer as the outermost layer may be directly laminated on the dermal base material, or the outermost layer 32 may be laminated on the dermal base material 2 via the primer layer 31 as shown in fig. 1. Further, the inner layer and the outermost layer may be laminated in this order on the dermal base material with the primer layer interposed therebetween. The wettability of the inner layer or the outermost layer can be improved by interposing the primer layer therebetween, and the adhesion of the inner layer or the outermost layer can be improved. Therefore, the abrasion resistance of the genuine leather product can be improved. Further, the undercoat layer also plays a role of filling pores on the surface of the dermal base material and adjusting the color by adding a colorant, so that unevenness of the inner layer and/or the outermost layer can be eliminated and the appearance can be improved.

It is important that the thickness of the finish layer (T2, see FIG. 1) is 2 to 10 μm. By making the thickness 2 μm or more, sufficient durability, specifically wear resistance, can be satisfied as a vehicle interior material. By making the thickness of the film 10 μm or less, a deep uneven pattern can be formed. The reason why such a deep uneven pattern can be formed by reducing the thickness of the finishing layer is not clear, and the reason is considered as follows. If the finishing layer is thick, the high-embossing portion (i.e., the convex portion of the mold) for forming the deep-recessed portion is cut (i.e., die-cut) before the finishing layer is spread (extended) when pressed. On the other hand, if the finishing layer is thin, the finishing layer is spread (stretched) following the pressing force by the pressing portion before being cut by the pressing portion. Therefore, it is considered that the finish layer forms a deep concave-convex pattern without generating cracks. Further, the surface portion to be pressed by the molded portion is likely to follow the pressing, and thus it is considered that cracking of the dermal base material can be prevented. The thickness of the finishing layer can be more than 3 μm, more than 4 μm and more than 5 μm; the thickness may be 9 μm or less, and may be 8 μm or less. In one embodiment, the thickness of the finishing layer may be, for example, 3 to 8 μm, and may be 4 to 6 μm.

In the case where the finishing layer includes a plurality of resin layers, the thickness of the finishing layer is the sum of the thicknesses of the plurality of resin layers. For example, when the finishing layer includes a primer layer and an outermost layer, the total of the thickness of the primer layer (T21, see fig. 1) and the thickness of the outermost layer (T22, see fig. 1) is defined as the thickness of the finishing layer. When the finishing layer includes the undercoat layer, the inner layer, and the outermost layer, the thickness of the undercoat layer, the thickness of the inner layer, and the thickness of the outermost layer are the total thickness of the finishing layer. As described later, the thickness of the resin layer formed only of the resin is set as the thickness of the undercoat layer, excluding the thickness of the penetrated portion. Therefore, the thickness of the finishing layer does not include the thickness of the penetration portion, i.e., the thickness of the finishing layer refers to the thickness of the resin layer on the dermal base material.

The expansion ratio of the finishing layer is not particularly limited, but is preferably 110% or more, more preferably 120 to 150%, and may be 120 to 140%. When the content is 110% or more, a deep uneven pattern can be formed, and the design is excellent. When the content is 150% or less, the die-cutting is less likely to occur, and a deep uneven pattern can be provided.

Here, the expansion ratio of the finishing layer means: a value obtained by dividing the surface area (a1) of the front surface of the finishing layer provided with the uneven pattern, which is expressed in percentage, by the projected area (a2) when the front surface is viewed from directly above. That is, the expansion ratio is (a1/a2) × 100. More specifically, the surface shape of the modified layer was measured and the surface area was calculated using an One shot 3D shape measuring machine (KEYENCE CORPORATION VR-3200). At this time, measurement was performed in a field of view into which a pattern (embossed pattern) having 3 uneven patterns entered, and image processing was performed. Then, in the range subjected to the image processing, the surface area (a1) and the projected area (a2) along the front surface of the uneven pattern were obtained, and the expansion ratio was calculated by the above equation.

The resin for forming the finishing layer is not particularly limited, and conventionally known resins can be used, and examples thereof include acrylic resins, urethane resins, and the like.

In one embodiment, the outermost layer is preferably formed of a composition containing an acrylic resin and/or a urethane resin (hereinafter, may be referred to as "resin composition for outermost layer").

The acrylic resin constituting the outermost layer is not particularly limited, and examples thereof include acrylic resins selected from alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, isobutyl acrylate, and 2-ethylhexyl acrylate; alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, isobutyl methacrylate, and 2-ethylhexyl methacrylate; hydroxyl group-containing acrylates such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and 4-hydroxybutyl acrylate; polymers of at least 1 monomer selected from the group consisting of acrylic acid, methacrylic acid and derivatives thereof, such as hydroxyl group-containing methacrylates such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate and 4-hydroxybutyl methacrylate, and modified products thereof. These monomers may be used alone in 1 kind or in combination of two or more kinds. Among these, from the viewpoint of abrasion resistance and water resistance, the acrylic resin is preferably a fluorine-modified acrylic resin, that is, a fluorine-modified acrylic resin. As the acrylic resin, commercially available products can be used, and an emulsion type is preferably used from the viewpoint of environmental load.

The amount of the acrylic resin to be blended in the resin composition for the outermost layer is not particularly limited, and is preferably 50% by mass or less, more preferably 15 to 40% by mass, and may be 15 to 25% by mass in terms of nonvolatile matter. That is, the content of the acrylic resin in the outermost layer is preferably 50% by mass or less. By setting the amount of the acrylic resin to 50% by mass or less, the coating film feel can be suppressed from becoming strong and the hand is not easily rough or hard. In the present specification, "nonvolatile components" mean: the ratio of the residual component to the original mass when sample 10g was heated at 120. + -. 10 ℃ for 3 hours to evaporate.

The urethane resin constituting the outermost layer is not particularly limited, and examples thereof include various polyurethanes such as polycarbonate-based polyurethane resin, polyether-based polyurethane resin, and polyester-based polyurethane resin. These may be used alone in 1 kind or in combination of two or more kinds. Among these, polycarbonate-based polyurethane resins are preferred from the viewpoint of abrasion resistance, polyether-based polyurethane resins are preferred from the viewpoint of touch and texture, and a combination of these is more preferred. The urethane resin may be a commercially available product, and is preferably a one-pack emulsion type in view of environmental load.

The amount of the urethane resin to be blended in the resin composition for the outermost layer is not particularly limited, and is preferably 50% by mass or less, more preferably 3 to 40% by mass, even more preferably 5 to 25% by mass, and may be 10 to 20% by mass, in terms of nonvolatile matter. That is, the content of the urethane resin in the outermost layer is preferably 50% by mass or less. By setting the amount of the urethane resin to 50% by mass or less, the coating film feel can be suppressed from becoming strong and the hand is not easily rough or hard. Further, by setting the amount of the urethane resin to 3% by mass or more, the film formability is good and the wear resistance can be improved.

In the present embodiment, as the resin constituting the outermost layer, an acrylic resin and a urethane resin may be used alone or in combination. From the viewpoint of texture, an acrylic resin is preferable, and from the viewpoint of abrasion resistance, a urethane resin is preferably used.

When the acrylic resin and the urethane resin are used in combination, the total amount of the acrylic resin and the urethane resin in the resin composition for the outermost layer is not particularly limited, and is preferably 17 to 90% by mass, more preferably 30 to 70% by mass, and may be 30 to 50% by mass in terms of nonvolatile components. That is, the sum of the contents of the acrylic resin and the urethane resin in the outermost layer is preferably 17 to 90% by mass. When the total amount is 17% by mass or more, the film formability is good and the wear resistance can be improved. When the amount is 90% by mass or less, the coating feel is suppressed from becoming strong and the hand is hardly coarsened and hardened.

The mass ratio (nonvolatile content) of the acrylic resin to the urethane resin is not particularly limited, and is preferably 1: 0.2-1: 1, more preferably 1: 0.5-1: 0.9. the wear resistance can be improved by setting the mass ratio of the urethane resin to the acrylic resin to 0.2 or more. Further, by setting the thickness to 1 or less, the coating feeling can be suppressed from becoming strong, the thickness of the finish layer can be suppressed from becoming thick, and the texture can be suppressed from becoming hard and rough.

The resin constituting the outermost layer is preferably mainly composed of an acrylic resin and/or a urethane resin, but may contain other resin components within a range not impairing the effects of the present invention. Examples of the other Resin component include an epoxy Resin and a silicone Resin (Resin).

From the viewpoint of abrasion resistance, the resin composition for the outermost layer preferably further contains a silicone rubber and a crosslinking agent. That is, from the viewpoint of wear resistance and the shape of the left or right of the uneven pattern, the outermost layer is preferably a resin layer containing an acrylic resin and/or a urethane resin and a silicone rubber and having a crosslinked structure with a crosslinking agent. In one embodiment, only the outermost layer of the finishing layer includes silicone rubber.

In the present embodiment, the silicone rubber used in the outermost layer is silicone having rubber elasticity at normal temperature (22 ℃), and is distinguished from silicone oil and silicone resin. The silicone rubber is a rubber having a siloxane bond in the main chain, and more specifically, a silicone having a linear structure molecule having a repeating number of siloxane bonds of 5000 to 10000 and capable of forming a rubber elastic coating film is exemplified.

The rubber elasticity of silicone rubber can be evaluated by the elastic modulus of a coating film formed of the silicone rubber (a rubber elasticity coating film of silicone rubber only). The elastic modulus of the rubber elastic coating is, for example, preferably 0.001 to 0.5MPa, more preferably 0.001 to 0.2MPa, still more preferably 0.01 to 0.1MPa, and may be 0.03 to 0.08 MPa.

Here, the elastic modulus of the rubber elastic coating film is calculated as follows. Specifically, a silicone rubber solution such as a silicone emulsion is applied to a flat release paper (EV130TPD, manufactured by linetec) with an applicator so that the thickness after drying is 30 to 100 μm, and then heat-treated at 80 ℃ for 10 minutes and then at 130 ℃ for 5 minutes to prepare a rubber elastic coating film. Collecting from the rubber elastic coatingA test piece having a length of 150mm and a width of 30mm was mounted on a jig of a tensile testing machine (AUTOGRAPHAG-IS, manufactured by Shimadzu corporation) at a clamping width of 30mm and a clamping interval of 50mm under the conditions of a room temperature of 22 + -2 ℃ and a relative humidity of 65 + -5% RH, and was stretched at a stretching speed of 200 mm/min, a ratio of a value obtained by dividing an elongation (mm) of the test piece by the clamping interval (mm) (elongation (mm)/50mm) × 100 was defined as an X-axis, and the obtained stress (N) was divided by a cross-sectional area (mm) of the test piece (mm)²) The resulting value (stress (N)/area cut (mm)²) Plotted as the Y-axis. From the resulting plot, the X-axis is calculated: the slope of the regression line with an elongation of 0.05 to 10% is used as the elastic modulus of the rubber elastic coating.

Specific examples of the silicone rubber include dimethyl silicone rubber, rubbers containing modified products of dimethyl polysiloxane (e.g., vinyl methyl silicone rubber, phenyl vinyl methyl silicone rubber, fluorosilicone rubber, etc.), silicone rubber-acrylic copolymers, silicone rubber-urethane copolymers, and the like. These may be used alone in 1 kind or in combination of two or more kinds. Among them, from the viewpoint of general versatility, at least 1 selected from the group consisting of dimethyl silicone rubber, vinyl methyl silicone rubber, phenyl vinyl methyl silicone rubber, and fluorosilicone rubber is preferable, and dimethyl silicone rubber is more preferable. In one embodiment, the silicone rubber to be blended in the resin composition for the outermost layer is preferably a silicone emulsion capable of forming a rubber elastic coating film by drying. That is, the silicone rubber constituting the outermost layer is preferably formed of a silicone emulsion capable of forming a rubber elastic coating by drying, and may be formed of a self-crosslinking silicone emulsion. The silicone rubber may be a commercially available one, and an aqueous emulsion type is preferably used because of ease of mixing with the urethane resin.

The amount of silicone rubber added to the resin composition for the outermost layer is not particularly limited, and is preferably 15 to 70% by mass, more preferably 30 to 60% by mass, and may be 35 to 50% by mass, in terms of nonvolatile matter. That is, the content of the silicone rubber in the outermost layer is preferably 15 to 70 mass%. By setting the amount of silicone rubber to 15% by mass or more, the coating film feel can be suppressed from becoming strong and the hand is not easily rough or hard. By setting the amount to 70% by mass or less, the touch and design properties are easily maintained.

The mass ratio (nonvolatile content) of the resin constituting the outermost layer (preferably the total amount of the acrylic resin and the urethane resin) to the silicone rubber is not particularly limited, and is preferably 1: 0.3-1: 2.2, more preferably 1: 0.5-1: 1.7, can be 1: 0.8-1: 1.3. by setting the mass ratio of the silicone rubber to the resin to 0.3 or more, the feel and hand of the obtained genuine leather product can be improved. In addition, when the amount is 2.2 or less, the resulting genuine leather product can be prevented from being excessively polished, and the design can be improved.

Examples of the crosslinking agent used for the outermost layer include carbodiimide-based crosslinking agents, aziridine-based crosslinking agents, and isocyanate-based crosslinking agents. These may be used alone in 1 kind or in combination of two or more kinds. Among them, isocyanate-based crosslinking agents are preferable. The crosslinking agent used in the outermost layer may be a commercially available one, and is preferably an emulsion type from the viewpoint of environmental load.

The carbodiimide-based crosslinking agent is not particularly limited, and can be appropriately selected from generally used carbodiimide-based crosslinking agents. Among them, those having 2 or more carbodiimide groups are preferable, and examples thereof include aromatic polycarbodiimides such as poly (4, 4' -diphenylmethane carbodiimide), poly (p-phenylene carbodiimide), poly (m-phenylene carbodiimide), poly (diisopropylphenyl carbodiimide), and poly (triisopropylphenyl carbodiimide); alicyclic polycarbodiimides such as poly (dicyclohexylmethane carbodiimide), and aliphatic polycarbodiimides such as poly (diisopropylcarbodiimide). These carbodiimide-based crosslinking agents may be used alone in 1 kind or in combination of two or more kinds.

The carbodiimide group of the carbodiimide-based crosslinking agent reacts with the carboxyl group of the resin used in the outermost layer to form an N-acylurea, thereby forming a three-dimensional crosslinked structure. This improves the adhesion to the dermal base material and the film-forming property of the outermost layer, and improves the abrasion resistance of the dermal product.

The blending amount of the carbodiimide-based crosslinking agent in the resin composition for the outermost layer is not particularly limited, and is preferably 2 to 5% by mass in terms of nonvolatile components. When the amount of the compound is 2% by mass or more, the strength of the coating film can be improved, and the abrasion resistance and the friction fastness can be improved. When the amount is 5% by mass or less, the hardness of the coating film can be prevented, and the texture can be made hard and hard.

The aziridine-based crosslinking agent is not particularly limited, and may be appropriately selected from commonly used aziridine-based crosslinking agents. Examples thereof include diphenylmethane-4, 4' -bis (1-aziridinecarboxamide), trimethylolpropane tri- β -aziridinylpropionate, tetramethylolmethane tri- β -aziridinylpropionate, toluene-2, 4-bis (1-aziridinecarboxamide), triethylenemelamine, bis-isophthaloyl-1- (2-methylaziridine), tri-1- (2-methylaziridine) phosphine, trimethylolpropane tri- β - (2-methylaziridine) propionate and the like. These aziridine-based crosslinking agents may be used alone in 1 kind or in combination of two or more kinds.

The aziridine group of the aziridine-based crosslinking agent reacts with a carboxyl group of the resin used in the outermost layer to form a three-dimensional crosslinked structure. This improves the adhesion to the dermal base material and the film-forming property of the outermost layer, and improves the abrasion resistance of the dermal product.

The blending amount of the aziridine-based crosslinking agent in the resin composition for the outermost layer is not particularly limited, and is preferably 1 to 2% by mass in terms of nonvolatile components. By setting the amount of the component to 1% by mass or more, the strength of the coating film can be improved. Thereby improving the wear resistance and the frictional fastness. When the amount is 2% by mass or less, the hardness of the coating film can be prevented, and the texture can be made hard and hard.

The isocyanate-based crosslinking agent is not particularly limited, and can be appropriately selected from among isocyanate-based crosslinking agents generally used. Examples thereof include aromatic diisocyanates such as phenylene diisocyanate, Toluene Diisocyanate (TDI), 4 '-diphenylmethane diisocyanate (MDI), 2, 4' -diphenylmethane diisocyanate, naphthalene diisocyanate, and xylylene diisocyanate; aliphatic diisocyanates and alicyclic diisocyanates such as Hexamethylene Diisocyanate (HDI), lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate, and tetramethylxylylene diisocyanate. These isocyanate-based crosslinking agents may be used alone in 1 kind or in combination of two or more kinds.

The isocyanate-based crosslinking agent reacts with active hydrogen and the like present in the resin component used in the outermost layer to form a crosslinked structure. This improves the film-forming property of the outermost layer, and improves the abrasion resistance of the genuine leather product.

The amount of the isocyanate-based crosslinking agent to be blended in the resin composition for the outermost layer is not particularly limited, and is preferably 3 to 20% by mass, more preferably 8 to 20% by mass, and may be 10 to 18% by mass in terms of nonvolatile matter. When the amount of the compound is 3% by mass or more, the strength of the coating film can be improved, and the abrasion resistance and the friction fastness can be improved. When the amount is 20% by mass or less, the hardness of the coating film can be prevented, and the texture can be made hard and rough.

The resin composition for the outermost layer (i.e., the resin liquid forming the outermost layer) may contain, as required, various additives such as a colorant (pigment, dye), a matting agent, a smoothing agent, a surfactant, a filler, a leveling agent, and a thickener. These may be used alone or in combination of 1. In addition to these additives, a solvent such as a highly polar solvent may be contained as necessary. As the solvent, water is preferably used from the viewpoint of environmental load.

In one embodiment, a silicone oil may be used as the smoothing agent. The silicone oil is a liquid silicone at room temperature, and specifically includes dimethylsilicone oil having a repeating number of siloxane bonds of less than 5000.

The outermost layer is formed by applying the resin composition for an outermost layer on the surface of the dermal base, the surface of the primer layer, or the surface of the inner layer, and then performing heat treatment.

In coating the resin composition for the outermost layer, various conventionally known methods can be employed. For example, a reverse roll coater, a spray coater, a roll coater, a gravure coater, a kiss roll coater, a knife coater, a comma coater, or the like can be used without particular limitation. Among them, coating by a reverse roll coater or a spray coater is preferable in that a uniform and thin coating film can be formed at a low coating amount. The coating thickness or the wet coating amount may be appropriately set according to the desired thickness of the outermost layer.

The resin is dried to evaporate the solvent in the resin solution, and heat treatment is performed to promote a crosslinking reaction between the resin and the crosslinking agent to form a coating film having sufficient strength. In order to prevent excessive evaporation of water from the dermal matrix, it is preferable to perform heat treatment so that the dermal matrix itself does not reach a temperature of 80 ℃ or higher. Therefore, the heat treatment temperature is preferably 90 to 130 ℃, and more preferably 100 to 120 ℃. The heat treatment time is preferably 1 to 5 minutes, and more preferably 2 to 3 minutes. By setting the heat treatment temperature and the heat treatment time to be not less than the lower limit values, insufficient drying and crosslinking reaction can be prevented. By setting the heat treatment temperature and the heat treatment time to be not more than the upper limit values, the touch and the touch can be prevented from becoming rough and hard.

The thickness of the outermost layer is not particularly limited, but is preferably 1 to 10 μm. The thickness of the outermost layer may be 2 μm or more, may be 3 μm or more, and may be 5 μm or more; further, the particle diameter may be 9 μm or less, 8 μm or less, or 7 μm or less. In one embodiment, the thickness of the outermost layer may be, for example, 2 to 7 μm, and may be 3 to 5 μm. By making the thickness of the outermost layer 1 μm or more, the abrasion resistance and the frictional fastness can be improved. By setting the thickness of the outermost layer to 10 μm or less, the design and feel peculiar to the dermis can be improved.

As described above, the finishing layer may be composed of only the outermost layer, may be provided with an undercoat layer together with the outermost layer, and may further have an inner layer. When the finishing layer is formed of a plurality of layers in this manner, the compositions of the resins constituting the outermost layer, the inner layer and the undercoat layer may be the same or different.

In one embodiment, the primer layer includes a mixed layer in which a resin and fibers of the dermal base material are mixed together, the mixed layer being formed by allowing the primer resin composition to permeate through the surface of the dermal base material. The primer layer may include a resin layer formed only of a resin on the surface of the layer, together with a layer in which the resin and the fibers of the genuine leather substrate are mixed.

The primer layer is formed by applying a resin composition for primer layer to the surface of the dermal substrate and then performing heat treatment. In one embodiment, the resin composition for the primer layer is applied to the surface of the dermal base material and heat-treated, and then the resin composition for the primer layer is applied again and heat-treated. This makes it possible to form a uniform coating film on the undercoat layer.

As the resin constituting the undercoat layer, the same acrylic resin and/or urethane resin as the above-described resin constituting the outermost layer can be used. Among them, a polycarbonate-based urethane resin is preferably used from the viewpoint of durability.

The resin composition for an undercoat layer (i.e., the resin liquid for forming the undercoat layer) may contain, together with the resin, other resin components (epoxy resin, silicone resin, etc.) and various additives (colorants (pigments, dyes), matting agents, smoothing agents, surfactants, fillers, leveling agents, adhesion promoters, etc.) as required in the same manner as the outermost layer. These may be used alone or in combination of 1. Among them, a colorant is preferably contained, and the colorant is preferably a pigment. This makes it possible to color the base coat layer, thereby reducing color unevenness of the dermal base material. In addition to these additives, a solvent such as a highly polar solvent may be contained as necessary. As the solvent, water is preferably used from the viewpoint of environmental load.

The viscosity of the resin composition for an undercoat layer is preferably low. Specifically, the measurement value is preferably 10 to 20 seconds by using a cup viscometer (viscosity cup NK-2, manufactured by Anest Iwata). When the viscosity is in this range, the resin liquid forming the primer layer easily penetrates the grain surface, and thus a layer in which the resin and the fibers of the genuine leather substrate are mixed can be formed as described above.

When the resin composition for an undercoat layer is applied, various methods known in the art can be used. For example, a reverse roll coater, a spray coater, a roll coater, a gravure coater, a kiss roll coater, a knife coater, a comma coater, or the like can be used without particular limitation. Among them, coating by a reverse roll coater or a spray coater is preferable in that a uniform and thin coating film can be formed at a low coating amount. The coating thickness or the wet coating amount can be appropriately set according to the desired thickness of the finishing layer.

The resin is dried to evaporate the solvent in the resin liquid, and heat treatment is performed to promote a crosslinking reaction between the resin and the crosslinking agent when the crosslinking agent is compounded, thereby forming a coating film having sufficient strength. In order to prevent excessive evaporation of water from the dermal matrix, it is preferable to perform heat treatment so that the dermal matrix itself does not reach a temperature of 80 ℃ or higher. Therefore, the heat treatment temperature is preferably 90 to 130 ℃, and more preferably 100 to 120 ℃. The heat treatment time is preferably 1 to 5 minutes, and more preferably 2 to 3 minutes. By setting the heat treatment temperature and the heat treatment time to be not less than the lower limit values, insufficient drying and crosslinking reaction can be prevented. By setting the heat treatment temperature and the heat treatment time to be not more than the upper limit values, the touch and the touch can be prevented from becoming rough and hard.

The thickness of the undercoat layer is not particularly limited, but is preferably 1 to 8 μm, and more preferably 1 to 3 μm. By setting the thickness to 1 μm or more, the adhesion and abrasion resistance between the inner layer and the outermost layer can be improved. By setting the thickness to 8 μm or less, the coating feeling can be suppressed from becoming strong, the thickness of the finish layer can be suppressed from becoming thick, and the texture is not easily made thick or hard. As described above, the primer layer includes a portion penetrating into the dermal base material (i.e., a layer in which the resin and the fibers of the dermal base material are mixed), and in the present specification, the thickness of the penetrating portion is not included in the thickness of the primer layer, and the thickness of the resin layer including only the resin is defined as the thickness of the primer layer.

When the inner layer is provided as a part of the finishing layer, the same acrylic resin and/or urethane resin as the resin constituting the outermost layer can be used as the resin constituting the inner layer. The resin composition for the inner layer (i.e., the resin liquid for forming the inner layer) may contain, as necessary, other resin components (epoxy resin, silicone resin, etc.), and various additives (coloring agent (pigment, dye), matting agent, smoothing agent, surfactant, filler, leveling agent, thickener, etc.) as in the outermost layer. In addition to these additives, a solvent such as a highly polar solvent may be contained as necessary. As the solvent, water is preferably used from the viewpoint of environmental load.

After the surface of the genuine leather base material is formed with the dressing layer as described above, the surface of the dressing layer is formed with the uneven pattern. Thus, the genuine leather product for vehicle interior decoration according to the embodiment was obtained. By shaping the uneven pattern after forming the finishing layer, it is possible to eliminate the problem (for example, the resin flows into the recessed portion or conversely the resin layer becomes thinner at the bottom of the recessed portion) when the resin layer is applied after shaping.

Examples of the method of forming the uneven pattern include embossing, ultrasonic thermal bonding (PINSONIC), and welding, and the forming can be performed using a mold having an uneven shape corresponding to the uneven pattern to be formed on the front surface of the genuine leather product. Therefore, the concave-convex pattern of one embodiment is formed by pressing a mold having a concave-convex shape. Here, the ultrasonic heat bonding processing is 1 type of embossing processing, and is a processing method of heat bonding an object by ultrasonic waves. The welding process is a process of thermally welding an object by high frequency.

The genuine leather product for vehicle interior trim according to the present embodiment can be used for various applications of interior trim materials for vehicles, such as interior trim materials for vehicles including seats for vehicles, ceiling materials, instrument panels, door linings, and steering wheels.