JP2006296996A - Real leather composite excellent in anti-hardening performance and anti-shrinkage performance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the durability of a cover material made of a real leather skin. <P>SOLUTION: The automotive real leather composite is composed of a real leather skin 10 and a film 20, which is disposed on the rear surface of the real leather skin 10, and has a moisture permeability at 80°C of not higher than 500 g mm/m<SP>2</SP>/day and a modulus of elasticity in tension at 25°C of not higher than that of the real leather skin 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a genuine leather skin material used for automobile interior parts.

  Genuine leather and synthetic leather are used as materials for skins of automobile seats, door trims, steering wheels, shift knobs, and the like. Although genuine leather has a high-class feeling, the genuine leather hardens or shrinks as it is used, so it is difficult to use it on the rear seat back upper surface, door trim waist, steering and other parts where light enters. For this reason, artificial products such as synthetic leather are often used for these parts instead of genuine leather.

  However, it cannot be denied that artificial products are inferior to genuine leather in terms of luxury and texture. For this reason, development of the technique which raises the durability of a genuine leather skin material was desired so that genuine leather skin material can be applied also to parts, such as a rear seat back upper surface.

As a technique for improving the skin material, a technique for lining another material on the back surface of the skin material has been proposed. For example, a technique for laminating a skin material lined with a urethane foam layer on a foamed laminated sheet via a hot melt film is disclosed (see Patent Document 1). However, what is solved by the technique of Patent Document 1 is prevention of delamination between the skin material and the foamed laminated sheet, and not the durability of the leather itself.
JP 2000-118319 A

  An object of the present invention is to enhance the durability of a skin material made of a genuine leather skin.

  The inventors of the present invention have studied the mechanism by which the leather skin material deteriorates, and have found that the leather deteriorates due to moisture entering and leaving through the back surface of the leather skin material. A coating film is formed on the surface of the genuine leather skin material in order to improve light resistance and wear resistance, and the entry and exit of moisture is suppressed. However, on the back of the leather cover material, the fibers of the genuine leather are exposed, and moisture can enter and exit relatively freely. For this reason, as moisture enters and exits repeatedly, the effects of hardening and shrinkage on the leather skin material gradually increase. Therefore, in the present invention, a film for suppressing the entry and exit of moisture is disposed on the back surface of the genuine leather skin.

  Further, if the elasticity of the film disposed on the back surface of the leather cover is higher than that of the leather cover, the texture of the leather cover may be lowered due to the elasticity of the film. For this reason, the film whose tensile elasticity is below the genuine leather skin is used.

Specifically, the present invention provides a genuine leather skin, a moisture permeability coefficient at 80 ° C. of 500 g · mm / m ² / day or less, and a tensile strength at 25 ° C., disposed on the back surface of the genuine leather skin. This is a genuine leather composite for automobiles comprising a film whose elasticity is equal to or less than the tensile elasticity of the genuine leather skin. The present invention also relates to an automotive interior part using the genuine leather composite as a skin material.

  Curing and shrinkage of the leather cover are suppressed by a sheet disposed on the back surface of the leather cover.

  FIG. 1 is a cross-sectional view of a genuine leather composite for automobiles of the present invention. The genuine leather composite has a genuine leather skin 10 and a film 20 disposed on the back surface of the genuine leather. In some cases, other members may be disposed on the genuine leather composite. The shape of the genuine leather composite is not particularly limited. It may be in the form of a sheet or may be cut in accordance with the shape of the application.

  If the genuine leather skin 10 is genuine leather, the kind and part of the animal are not particularly limited. Examples of animals include cows, horses, and sheep. The part is not particularly limited, and for example, a part of leather that can be used as genuine leather, such as the back, buttocks, and stomach, may be used. The genuine leather skin 10 is preferably subjected to various treatments for improving the durability and texture of the leather. For example, a coating film for improving light resistance and wear resistance is usually formed on the surface side.

The film 20 is disposed on the back surface of the genuine leather skin 10. The film 20 is composed of a member that is difficult for moisture to pass through in order to prevent moisture from entering and exiting through the back surface of the genuine leather skin 10. Specifically, the moisture permeability coefficient at 80 ° C. of the film is 500 g · mm / m ² / day or less, preferably 100 g · mm / m ² / day or less, more preferably 10 g · mm / m ² / day or less. It is.

When the moisture permeability coefficient of the film exceeds 500 g · mm / m ² / day, moisture enters and exits between the inside and outside of the leather skin, and the leather skin cannot be cured or shrunk due to repeated moisture absorption. There is a fear. The lower limit of the moisture permeability coefficient of the film is not particularly limited, and the lower the moisture permeability coefficient of the film, the harder it is to harden or shrink even when used for a long time in a severe environment.

  The method for measuring the moisture permeability coefficient is not particularly limited as long as reliable data can be obtained. However, when a significant difference occurs in the measurement data depending on the measurement method of the moisture permeability coefficient, the numerical value obtained by the measurement method used in the examples described later is used as the moisture permeability coefficient in the present application.

  In addition, the film 20 is made of a material having low tensile elasticity in order to suppress deterioration of the genuine leather skin due to the film. Specifically, the tensile elasticity of the film at 25 ° C. is less than or equal to the tensile elasticity of the leather skin. Here, the tensile elasticity means a stress when the material is pulled, and a small tensile elasticity means that the material is easily stretched. When the tensile elasticity of the films to be superimposed is large, the back side of the genuine leather is restrained by the film, and the texture of the genuine leather may be impaired. In addition, when the leather cover is folded inward, an unnatural crease may occur on the surface of the leather cover. By using a film made of a material having a small tensile elasticity and easily stretched, the occurrence of unnatural creases can be suppressed.

  The smaller the tensile elasticity of the film, the more effectively the problems that occur in the leather skin can be suppressed. The tensile elasticity of the film is preferably 50% or less, more preferably 30% or less, and even more preferably 10% or less, with respect to the tensile elasticity of the genuine leather skin.

  Considering that the vehicle is used in a wide temperature range, it is preferable that the tensile elasticity of the film satisfies the above relationship in a wide temperature range. Preferably, the tensile elasticity at 10 to 30 ° C., more preferably 0 to 40 ° C., more preferably −10 to 50 ° C., and still more preferably −50 to 120 ° C. is equal to or lower than the tensile elasticity of the leather skin, more preferably It is 50% or less of the tensile elasticity of the leather skin, more preferably 30% or less of the tensile elasticity of the leather skin, and particularly preferably 10% or less of the tensile elasticity of the leather skin.

  The method for measuring the tensile elasticity is not particularly limited as long as reliable data can be obtained. For example, it can be measured according to a known method such as JIS K7161. However, when a significant difference occurs in the measurement data depending on the measurement method of tensile elasticity, the numerical value obtained by the measurement method used in the examples described later is taken as tensile elasticity in the present application.

  The material of the film is not particularly limited as long as it satisfies the aforementioned moisture permeability coefficient and tensile elasticity. Preferred materials include polyester, polyurethane, polyamide, polyolefin, styrenic thermoplastic elastomer, styrenic rubber and modified products thereof. Two or more of these may be used in combination. These polymer compounds may be copolymers synthesized from two or more monomers. Here, the modified product refers to a compound having a structure obtained by modifying an exemplified polymer such as polyester with a functional group or a side chain.

  Polyester refers to a polymer having an ester bond (—O—CO—) obtained by polycondensation of a polybasic acid and a polyhydric alcohol in the main chain. Examples of polyesters include unsaturated polyesters; alkyd resins; thermoplastic polyesters synthesized by condensation of terephthalic acid and ethylene glycol, such as polyethylene terephthalate and polybutylene terephthalate.

  Polyurethane refers to a polymer compound having a urethane bond in the main chain. For example, it can be obtained by polyaddition reaction of diisocyanate (OCN-RN-CO) and a polyhydric alcohol such as diol (HO-R'-OH).

  Polyamide refers to a linear polymer having an amide bond (—CO—NH—) in the molecule. Examples of polyamides include polyamides obtained by ring-opening polymerization of lactams, polyamides obtained by polycondensation of aminocarboxylic acids, polyamides obtained by polycondensation of diamines and dibasic acids, and the like.

  Polyolefin refers to an olefin polymer. Examples of the polyolefin include polyethylene, polypropylene, polyisobutylene, polyisoprene and the like. Copolymers such as polyethylene vinyl acetate (EVA) may be used.

  Styrenic thermoplastic elastomer refers to a thermoplastic elastomer having a styrene structure in the main chain. Styrene rubber refers to rubber having a styrene structure in the main chain. Examples of styrenic thermoplastic elastomers and styrene rubbers include styrene / butadiene / styrene block copolymer (SBS), styrene / ethylene / butylene / styrene block copolymer (SEBS), and styrene / isoprene / styrene block copolymer (SIS). Can be mentioned.

  In selecting a material to be actually used for a film, the material may be selected in consideration of a moisture permeability coefficient and tensile elasticity. Further, the material may be modified so that the moisture permeability coefficient and the tensile elasticity become desired values. Among the above-mentioned compounds, polyester, polyolefin, polyethylene vinyl acetate, styrenic thermoplastic elastomer, and modified products thereof are preferable because they can easily suppress the moisture permeability coefficient in terms of molecular structure. Of these, polyester and this modified product are preferable because they can easily control the moisture permeability coefficient and tensile elasticity. For other compounds, it is possible to reduce the moisture permeability coefficient by reducing the amount of urethane bonds in the polyurethane molecule or amide bonds in the polyamide molecule.

  The thickness of the main skin is not particularly limited. Since the skin is a natural material, its thickness depends to some extent on the raw material. The thickness of the film is not particularly limited as long as the moisture permeability coefficient and the tensile elasticity are in the desired ranges. However, if the film is too thick, the formed leather composite may become hard. Usually, the thickness of the film is about 30 to 100 μm. However, the technical scope of the present invention is not limited to this range.

  In addition, materials other than a genuine leather skin and a film may be arrange | positioned as needed.

  As a method of attaching the film to the back of the leather cover, a method of fusing the film to the leather cover by hot press, a method of bonding the leather cover to the film using an adhesive, or a method using an adhesive tape Examples include a method of adhering a leather skin and a film. After the film is separately formed, the film may be formed by a method other than the method of attaching to the leather cover. For example, the film may be a resin layer formed by coating a resin on the back surface of a genuine leather skin.

  When the method of fusing the film to the leather cover by hot pressing is employed, a hot melt film is used as the film. Preferably, a hot melt film that is fused to the genuine leather skin at a temperature 10 to 150 ° C. higher than the melting point of the film is used. Examples of materials that can be used as the hot melt film include polyester, polyurethane, polyamide, polyolefin, styrene thermoplastic elastomer, and styrene rubber.

  In order to attach the film by hot pressing, first, the leather cover and the film are superposed and the film is heated to a temperature 10 to 150 ° C. higher than the melting point of the film to melt the film. The melted film is pressurized and sticks to the leather cover. The heating temperature and the applied pressure are selected depending on the film to be attached.

  In order to attach the film with an adhesive, the adhesive may be applied to one or both of the back surface of the leather cover or the film, and the leather cover and the film may be overlaid and pressed. You may heat with pressurization as needed. The type of the adhesive is not particularly limited as long as it is a material capable of bonding the genuine leather and the film. The method for applying the adhesive is not particularly limited. Methods such as brushing, spraying and roll coater are appropriately selected.

  In order to attach the film with the adhesive tape, an adhesive tape such as a double-sided tape may be attached to the back surface of the leather cover or one or both of the films, and the leather cover and the film may be superposed and pressed.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, the technical scope of this invention is not limited by a following example. In addition, the evaluation method of various table values is as follows.

(Measurement method of tensile elasticity)
Both ends of the test piece (30 mm × 150 mm) are fixed with a gripping jig, and the tensile elasticity when pulled at a gripping width of 30 mm, a gripping interval of 100 mm, and a gripping jig speed of 200 mm / min using an apparatus conforming to JIS K7161 is JIS K7161. Calculated according to The numerical values shown in Table 1 are tensile elasticity at 25 ° C.

(Measurement method of moisture permeability)
The moisture permeability coefficient of the film was calculated by measuring the water vapor transmission rate of the film. FIG. 2 is a plan view of the apparatus used for calculating the moisture permeability coefficient of the film, and FIG. 3 is a cross-sectional view taken along the line III-III in FIG.

  A rubber O-ring 40 having a wire diameter Φ of 3 mm was set in the groove of the Al cup 30 shown in FIG. 30 ml of pure water was put inside the Al cup 30 and covered with a film whose moisture permeability coefficient was measured. A SUS lid 50 was placed on the film and fastened with bolts / nuts 60. The diameter Φ of the hole formed for fastening the SUS lid 50 with the bolt / nut 60 was 5 mm. The SUS lid 50 used was formed with a vent hole 55 having the shape shown in the figure. The diameter Φ of the air hole was 7 mm.

In this state, it was left to stand in an atmosphere having a temperature of 80 ° C. and a humidity of 5%, and the mass of the apparatus was weighed at intervals of 1 hour. As a weighing apparatus, an electronic balance (AEX-200G) manufactured by Shimadzu Corporation was used. Moreover, as a thermostat for temperature control, a thermostat (PVH-211) manufactured by Tabai Espec Co., Ltd. was used. The moisture permeability coefficient (g · mm / m ² / day) was calculated from the mass reduction amount when the mass reduction amount per hour reached a constant value by the following formula. In addition, the film area in a following formula means the total area of the area | region which the water vapor | steam inside a container can permeate | transmit.

(Measurement method of shrinkage)
The shrinkage ratio of the leather composite was calculated by the following wet heat shrinkage test.

  (1) A test piece of 110 mm × 110 mm was prepared and allowed to stand for 48 hours or more in a standard state of 23 ° C. and 50%. Thereafter, marking was performed to about 100 mm in length and width, and the distance between scores was accurately measured.

  (2) The test piece was left still in a constant temperature bath of 100 ° C. × 22 h, and then left in a constant temperature and humidity bath of 20 ° C. × 65% RH × 30 min. Furthermore, it left still in a 50 degreeCx95% RH * 1h thermostat, and left still in a 20 degreeCx65% RH * 30min thermostat.

  (3) The cycle of (2) was repeated 5 times.

  (4) The test piece was allowed to stand in a constant temperature bath of 100 ° C. × 22 h, and then left in a constant temperature and humidity bath of 20 ° C. × 65% RH × 30 min. The distance between the vertical and horizontal scores of the test piece was measured, and the shrinkage rate was calculated by the following formula.

e: Vertical / horizontal average of distance between grades in genuine leather composite after wet heat shrinkage test
f: Vertical / horizontal average of distance between ratings in leather composite before wet heat shrinkage test (Method of measuring curing rate)
The curing rate of the genuine leather composite was determined by measuring the bending resistance and calculating the curing rate based on the bending resistance.

  The measuring method of the bending resistance is as follows. First, a test piece (25 mm × 200 mm) was placed in accordance with the scale on a 45 ° cantilever test machine table shown in JIS L1096, and a pressing plate having the same size as the test piece was placed on the test piece. The test piece was gently pushed out together with the holding plate until one end of the test piece was in contact with the 45 ° slope, and the position scale difference of the other end of the test piece when the one end of the test piece was in contact with the slope was measured in mm.

  The initial curing rate (after press-bonding) was calculated by the following formula.

a: Bending softness of the leather composite after the leather is overlaid and stabilized
b: Bending softness of genuine leather The curing rate after the wet heat shrinkage test was calculated by the following formula.

c: Bending softness of leather composite after wet heat shrinkage test
d: Bending softness of leather composite before wet heat shrinkage test (appearance evaluation)
The initial crease of the leather composite was evaluated and scored by the following method.

  The genuine leather composite after the leather was overlaid and stabilized was scored by the following method for surface creases formed when the skin side of the leather was folded inward. The A4 size genuine leather composite was folded at R20 with the silver side facing inward, and wrinkles generated in the vicinity of the bent portion were evaluated. The evaluation criteria are as follows.

○: Not unnatural folds compared to genuine leather △: Unnatural folds compared to genuine leather ×: Many unnatural folds compared to genuine leather Composite leather after wet heat shrinkage test The appearance of was evaluated by observing wrinkles generated on the silver surface side in a flat state. The evaluation criteria are as follows.

○: Unnatural wrinkles compared to genuine leather after wet heat shrinkage test △: Unnatural wrinkles compared to genuine leather after wet heat shrinkage test ×: Compared with genuine leather after wet heat shrinkage test There are many unnatural wrinkles (Examples 1-7, Comparative Examples 1-4)
A genuine leather composite was produced using the materials described in Table 1 as the genuine leather skin and film. As a method for joining the leather surface and the film, in Examples 1 to 5 and Comparative Examples 2 to 4, a method of fusing the film to the leather surface by hot pressing was used. In Example 6, a method of adhering a genuine leather skin and a film with an adhesive (epoxy adhesive EP-001 manufactured by Cemedine, tensile strength: 113 kgf / cm ² ) was used. In Example 7, a method of attaching the leather cover and the film with a double-sided tape that is an adhesive tape (acrylic double-sided tape No. 500 manufactured by Nitto Denko Corporation, tensile strength: 105 kgf / cm ² ) was used. In addition, the comparative example 1 is an experiment example about the genuine leather outer skin to which the film is not joined.

  In addition, the material of the film used by the Example and the comparative example is as follows.

Examples 1, 2, 6, 7: Polyester (modified polybutylene terephthalate)
Example 3: Polyolefin (ethylene / acrylic ester / maleic anhydride terpolymer)
Example 4: Polyolefin (ethylene vinyl acetate)
Example 5: Styrenic thermoplastic elastomer (hydrogenated styrene / ethylene / butylene block copolymer)
Comparative Examples 2 and 3: Polyurethane (Danfuse 6730A manufactured by Nitto Boseki Co., Ltd.)
Comparative Example 4: Polyamide (Nylon 6/66/12 copolymer)

  As described above, the leather composite of the present invention maintains the original texture of the leather, suppresses the generation of unnatural wrinkles, and also cures and shrinks the leather due to repeated moisture entry and exit. It turns out that it is suppressed.

  The leather composite of the present invention can be applied to various products. In particular, it is preferably applied to automobiles that require durability over a long period of time.

It is sectional drawing of the genuine leather composite body for motor vehicles of this invention. It is a top view of the apparatus which calculates the moisture permeability coefficient of a film. It is sectional drawing in the III-III surface of the apparatus of FIG.

Explanation of symbols

  10 ... Genuine leather skin, 20 ... Film, 30 ... Al container, 40 ... O-ring, 50 ... SUS lid, 55 ... Vent, 60 ... Bolt / nut.

Claims (12)

Genuine leather skin,
A film having a moisture permeability coefficient at 80 ° C. of 500 g · mm / m ² / day or less, and a tensile elasticity at 25 ° C. of less than or equal to the tensile elasticity of the leather skin, ,
A genuine leather composite for automobiles. ^2. The genuine leather composite for automobile according to claim 1, wherein the film has a moisture permeability coefficient at 80 ° C. of 100 g · mm / m ² / day or less. The genuine leather composite for automobiles according to claim 2, wherein the film has a moisture permeability coefficient at 80 ° C. of 10 g · mm / m ² / day or less.   The genuine leather composite for automobiles according to any one of claims 1 to 3, wherein the tensile elasticity of the film is 50% or less of the tensile elasticity of the leather skin.   The genuine leather composite for automobiles according to claim 4, wherein the tensile elasticity of the film is 30% or less of the tensile elasticity of the leather skin.   The genuine leather composite for automobiles according to claim 5, wherein the tensile elasticity of the film is 10% or less of the tensile elasticity of the genuine leather skin.   The said film consists of 1 or more types selected from the group which consists of polyester, a polyurethane, polyamide, polyolefin, a styrene-type thermoplastic elastomer, a styrene-type rubber, and these modified substances, The any one of Claims 1-6. Genuine leather composite for automobiles.   The genuine leather composite for automobiles according to claim 7, wherein the film is made of polyester or a modified product thereof.   The genuine leather composite for automobiles according to any one of claims 1 to 8, wherein the film is a hot melt film that is fused to the genuine leather skin at a temperature 10 to 150 ° C higher than a melting point of the film.   The automobile genuine leather composite according to any one of claims 1 to 8, wherein the film is superimposed on the leather outer skin with an adhesive.   The automobile genuine leather composite according to any one of claims 1 to 8, wherein the film is superimposed on the genuine leather skin with an adhesive tape.   The interior component for motor vehicles which used the genuine leather composite_body | complex of any one of Claims 1-11 as a skin material.

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