JP2000006334A - Phermoplastic polyolefin resin skin material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the subject skin material made suitable for an interior material of a car performing high development molding because thermal stretch molding can be performed without generating a crack or breaking. SOLUTION: A thermoplastic polyolefin resin skin material has a thermoplastic polyolefin resin sheet, the chlorine-free modified polyolefinic primer layer applied to the surface of the sheet and the topcoat layer applied to the primer layer. In this case, the topcoat layer is based on 100 pts.wt. polycarbonate polyurethane resin 100 (a) with a number average mol.wt. of 8,000 or more and 100% modulus of 20 kgf/cm2 or more and 0.1-40 pts.wt. (meth)acrylate/ butadiene/styrene resin (b).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic polyolefin resin skin material used for interior parts of automobiles, and more particularly to a thermoplastic polyolefin resin skin material that does not substantially crack or break even when it is heated.

[0002]

2. Description of the Related Art Interior parts such as instrument panels of automobiles must not only be integrally formed into a complicated shape, but also have good feel such as flexibility and elasticity, and have a surface having a good feeling. It must be in a matte state such as squeezing. Therefore, conventionally, a foamed layer is provided between a base material of an interior part such as an instrument panel and a skin layer, and the surface of the skin layer is subjected to squeezing or matte coating.

[0003] Conventionally, the skin of interior parts has a touch, abrasion resistance,
In consideration of weather resistance, durability and the like, it is formed of a polyvinyl chloride resin, and the internal foam layer is mainly formed of a polyurethane foam. The base material is moldable,
Considering strength and durability, polypropylene and ABS
It was formed of resin or the like. Since the conventional interior parts having such a laminated structure are made of different resins, it is necessary to separate each resin when recycling. However, it is not only time-consuming to separate the polyvinyl chloride resin skin layer and the ABS resin or polypropylene base material adhered by the polyurethane foam layer, but also the cross-linked foam polyurethane layer cannot be reused. There was a problem. In addition, since gases that adversely affect the environment are generated at the time of incineration of polyvinyl chloride resin, it must be incinerated by a large incinerator equipped with environmental measures. For this reason, interior parts of automobiles are finely crushed and then disposed of at a disposal site as dust.

[0004] In view of recent garbage problems and environmental problems, recycling of interior parts has been strongly desired in order to reduce waste materials generated from automobiles as much as possible, and some implementations have been attempted. For that purpose, it is preferable to unify the resin components of each layer to those of the same system, particularly to a polyolefin resin.
If the skin of the interior part is made of a thermoplastic polyolefin resin, the coatability is reduced. Therefore, it is necessary to apply a primer to the surface or perform a corona discharge treatment. In addition, in consideration of production efficiency, a surface-coated skin sheet is prepared in advance,
In addition, it is common to bond and laminate a polypropylene foam and a base sheet, and vacuum form them.

[0005] Chlorinated polypropylene coatings and reactive coatings containing saturated polyesters and polyisocyanates are known as primers for coating the surface of a skin sheet made of a thermoplastic polyolefin resin. Apply a reactive paint containing saturated polyester resin and polyisocyanate to the surface of the skin sheet coated with a chlorinated polypropylene primer or the surface of the skin sheet that has been subjected to corona discharge treatment. A method of applying a paint containing a resin or the like, a paint obtained by adding a polyisocyanate thereto, or a polyurethane paint has been proposed.

[0006] Specifically, for example, Japanese Patent Application Laid-Open No. Sho 60-197741 discloses a method for producing a sheet used for the skin of an instrument panel or the like among automotive interior materials. Forming a sheet from a raw material containing an α-olefin-based copolymer, and applying a reactive paint containing a saturated polyester resin, an acrylate resin and an isocyanate resin to the surface of the sheet; A manufacturing method is disclosed.

[0007] Japanese Patent Publication No. 7-14655 discloses a car ceiling,
A method for producing a printed composite sheet for a skin used for a door rim or the like, comprising applying a chlorinated polypropylene primer to one surface of a skin sheet made of a thermoplastic elastomer such as a polypropylene elastomer, and then applying an acrylic resin Printing with an ink composition in which the ink is blended with a mixed processing agent comprising a polyester resin and a saturated polyester resin, and the resulting skin sheet made of a thermoplastic elastomer with printing is fused onto one or both sides of a pad made of a polypropylene foam. Disclosed is a method of unifying and integrating.

Further, Japanese Patent No. 2533147 discloses that (a) 90 to 20 parts by weight of an ethylene / α-olefin copolymer rubber, and (b)
10 to 80 parts by weight of polyolefin resin (however, (a) + (b) =
100 parts by weight), and if necessary, (c) a peroxide non-crosslinked hydrocarbon-based rubber-like substance, and (d) a mineral oil-based softener 0 to 200.
Parts by weight of a partially crosslinked copolymer rubber composition (I) 100 obtained by dynamically heat-treating the mixture comprising
Selected from saturated polyesters and chlorinated polyolefins, on the surface of a thermoplastic elastomer molded product consisting of up to 30 parts by weight and 0 to 70 parts by weight of a polyolefin resin (II) (100 parts by weight of (I) + (II)). A primer layer containing at least one compound is provided, and on this primer layer,
Topcoat layer containing at least one compound selected from saturated polyester, acrylate resin, polyvinyl chloride and isocyanate resin (however, when the primer layer is composed of only saturated polyester, the topcoat layer is at least an acrylate ester (Including a resin) is disclosed.

[0009]

However, any of the skin materials according to the prior art described above has a problem that cracks and breaks occur on the surface when the skin material is heated and formed into a desired interior part shape. In recent years, spray coating has increased in order to improve the appearance of molded articles. However, spray coating worsens this phenomenon. In addition, Japanese Patent Application Laid-Open No. 60-197741 and
In 7-14655, chlorinated polyolefin resin such as chlorinated polypropylene is used for the primer, which not only has poor durability against hydrocarbon solvents such as petroleum benzene, volatile oil, etc. It has the disadvantage of causing discoloration.

[0010] Accordingly, an object of the present invention is to provide a thermoplastic polyolefin resin skin material suitable for interior parts of automobiles to be subjected to high expansion molding, since it is possible to perform heat-stretch molding without substantially causing cracks or breakage. To provide.

[0011]

In view of the above objects, the present inventors have conducted various studies on a primer and a top coat applied to a thermoplastic polyolefin resin sheet. As a result, the present inventors have found that the composition of the conventional top coat and reactive primer is In order to avoid the lack of the ability to follow rapid stretching during heating, and to avoid this, apply a top coat having a composition that can sufficiently follow even a sudden stretching force on a non-reactive olefin primer. Focused on what must be done. As a result, as a top coat applied on the chlorine-free modified polyolefin-based primer, by using a polycarbonate-based polyurethane resin base to which (meth) acrylates-butadiene-styrene resin is added, the tensile strength at the time of heating and The inventors have found that the elongation at break is remarkably improved and is suitable for a thermoplastic polyolefin resin skin material, and reached the present invention.

That is, the thermoplastic polyolefin resin skin material of the present invention comprises a thermoplastic polyolefin resin sheet,
It has a chlorine-free modified polyolefin-based primer layer applied on the sheet, and a top coat layer applied on the primer layer, wherein the top coat layer has (a) a number average molecular weight of 8000 or more and a 100% modulus. Is 20 kgf / cm ² or more of 100 parts by weight of a polycarbonate polyurethane resin,
(b) (meth) acrylates-butadiene-styrene resin in an amount of 0.1 to 40 parts by weight as a main component.

[0013]

According to the present invention, a non-reactive chlorine-free modified polyolefin-based primer is applied to a thermoplastic polyolefin resin sheet, and a top coat having a number average molecular weight of at least 8000 and a 100% modulus of at least 20 kgf / cm ^2. For 100 parts by weight of polycarbonate polyurethane resin,
(Meth) acrylates-butadiene-styrene resin
By applying a top coat containing a vehicle as a main component mixed with 0.1 to 40 parts by weight, it is possible to provide a thermoplastic polyolefin resin skin material which is easily heat-stretched. Although the reason for this is not necessarily elucidated, the polycarbonate-based polyurethane resin has sufficient stretchability, and the (meth) acrylates-butadiene-styrene resin imparts mechanical strength and rubber elasticity, and substantially cracks and breaks. It is considered that this is because the stretchability is improved without causing cracks.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [1] Layer Structure of Skin Material (A) Thermoplastic Polyolefin Resin Sheet (1) Composition The thermoplastic polyolefin resin constituting the sheet is a polypropylene resin such as polypropylene, propylene-ethylene copolymer or the like. And ethylene-propylene rubber (EP
R), at least one polyolefin resin selected from the group consisting of olefin elastomers such as ethylene-butene rubber (EBR) and ethylene-propylene-diene terpolymer (EPDM). In order to have good mechanical strength and good flexibility and elasticity, it is preferable to use a thermoplastic elastomer composed of a polypropylene resin and an olefin-based elastomer.

The polypropylene resin may be not only a homopolymer of propylene but also a copolymer of propylene with another α-olefin. As α-olefins, ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-
Penten and the like. Among the propylene-α-olefin copolymers, a propylene-ethylene copolymer is preferred. The ethylene content in the propylene-ethylene copolymer is preferably at most 40% by weight. If the ethylene content exceeds 40% by weight, the mechanical strength decreases. Melt flow rate of polypropylene resin (MFR, 230 ° C, 2.
The load of 16 kg, JISK7210) is preferably about 5 to 100 g / 10 minutes.

The olefin elastomer preferably has an ethylene content of 30 to 80% by weight, has an iodine value (unsaturation degree) of 30 or less, and has a Mooney viscosity ML _{1 + 8} (127 ° C.).
Is preferably about 10 to 200. The crystallinity of such an olefin-based elastomer is usually 40% or less.

When the thermoplastic elastomer is used, the weight ratio of the polypropylene resin to the olefin elastomer is preferably about 5/95 to 80/20. If the polypropylene resin is less than 5% by weight (the olefin-based elastomer exceeds 95% by weight), the mechanical strength decreases, while if the polypropylene resin exceeds 80% by weight (the olefin-based elastomer is less than 20% by weight), Rubber-like physical properties decrease.

In order to impart good durability to the surface of the sheet, it is preferred that the thermoplastic polyolefin resin is at least partially crosslinked. For this purpose, it is necessary to add a peroxide crosslinking agent such as dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, or t-butylcumyl peroxide. preferable. The compounding amount of the peroxide-based cross-linking agent is 0.1 part with respect to 100 parts by weight of the polypropylene resin and / or the olefin-based elastomer.
It is about 01 to 0.05 parts by weight. Further, a crosslinking aid may be added.

If necessary, the thermoplastic polyolefin resin may contain an inorganic filler such as talc, calcium sulfate, barium sulfate, mica, calcium silicate, etc. in addition to an antioxidant, an ultraviolet absorber, an antistatic agent, a flame retardant, a pigment. Materials and the like may be blended.

(2) Thickness The thickness of the thermoplastic polyolefin resin sheet is preferably 0.3 mm or more, more preferably 0.4 to 0.8 mm. The thickness of the thermoplastic polyolefin resin sheet is 0.3
If it is less than mm, not only the mechanical strength and durability are not sufficient, but also it is difficult to prevent defects such as unevenness from being generated on the surface after the following vacuum forming step.

(B) Primer layer (1) Composition As a primer, 2 mg of a hydroxyl group or a carboxyl group is used.
A resin mainly composed of a chlorine-free modified polyolefin-based resin added in an amount of equivalent / g or less is preferable. To introduce a hydroxyl group or a carboxyl group into the polyolefin resin, a solution polymerization method, a suspension polymerization method, an emulsion polymerization method, a melt-kneading method in the presence of a peroxide, etc., can be used by any method, and a random polymer, Any of a block polymer and a graft polymer may be used. Above all-(CH ₂ -CH (CH ₃ )) _m-
A graft copolymer having a basic structure of (CH ₂ -CX (CH ₃ )) _n- (where X is a hydroxyl group or a carboxyl group, and m and n are the numbers of the respective structural units) is preferable. In the case of a graft copolymer into which a hydroxyl group has been introduced, it can be obtained by melt-kneading polypropylene and an unsaturated ester or ether having a hydroxyl group in the presence of a peroxide. In the case of a graft copolymer having a carboxyl group introduced, it can be obtained by melt-kneading polypropylene and an unsaturated carboxylic acid or anhydride thereof in the presence of peroxide.

To introduce a hydroxyl group, a hydroxy group-containing (meth) acrylate such as hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxybutyl (meth) acrylate, N-methylolacrylamide, etc. It is preferable to use, and particularly preferable is 2-hydroxyethyl (meth) acrylate and the like. In order to introduce a carboxyl group, it is preferable to use an unsaturated carboxylic acid or its anhydride. Examples of unsaturated carboxylic acids or anhydrides thereof include monocarboxylic acids such as acrylic acid and methacrylic acid, maleic acid, fumaric acid, dicarboxylic acids such as itaconic acid, maleic anhydride, and dicarboxylic anhydrides such as itaconic anhydride. Is mentioned.

The added amount of hydroxyl group or carboxyl group is 2 mg
It is preferably not more than equivalent / g. The addition amount of the hydroxyl group or carboxyl group of 2 mg equivalent / g or less is sufficient, and if it exceeds that, no further improvement in the performance as a primer is obtained, and only the production cost increases. A more preferred addition amount of a hydroxyl group or a carboxyl group is 0.5 to 1.5 mg equivalent / g.
It is.

The polyolefin resin containing a hydroxyl group or a carboxyl group is preferably a propylene-based resin, but may further contain a comonomer such as ethylene.

A primer based on a polyolefin resin containing a hydroxyl group or a carboxyl group is commercially available, for example, AD-456M (manufactured by Tokuseki Shigyo Kogyo KK), Unistor P-801, P-401 (Mitsui Chemicals, Inc.) Co., Ltd.).

(2) Coating Amount The coating amount of the primer is preferably 10 to 100 g / m ² (when wet). If the amount of the primer applied is less than 10 g / m ² , the adhesion between the thermoplastic elastomer sheet and the top coat is insufficient, and if it exceeds 100 g / m ² , it is meaningless. Since the thickness of the primer layer is reduced to about 1/10 by drying, the dried thickness is about 1 to 10 g / m ² .

(C) Topcoat layer (1) Composition (a) Polycarbonate polyurethane resin The polycarbonate polyurethane resin is formed by reacting an isocyanate group of an isocyanate compound with a terminal hydroxyl group of polycarbonate diol, and has a number average molecular weight. Is 8000 or more, and the 100% modulus is 20 kgf / cm ² or more.

The polycarbonate diol can be produced by subjecting a low molecular diol to a transesterification reaction with a carbonate precursor such as a dialkyl carbonate (eg, dimethyl carbonate). As the low molecular diol, it is preferable to use an aliphatic diol such as 1,4-butanediol and 1,6-hexanediol, and an alicyclic diol such as 1,4-cyclohexanediol. Commercially available polycarbonate diols include, for example, Desmophen D-2020E (manufactured by Bayer).

As the isocyanate compound, aliphatic polyisocyanate such as hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPD
And alicyclic polyisocyanates such as I) and aromatic polyisocyanates such as hydrogenated diphenyl diisocyanate, diphenylmethane-4,4'-diisocyanate (MDI), and hydrogenated MDI. In any case, a non-yellowing type is preferred.

The polycarbonate polyurethane resin is
It can be produced by reacting an isocyanate compound with a polycarbonate diol produced by a transesterification reaction from a low molecular weight diol and a dialkyl carbonate in a molar ratio of 1: 1 to 1: 2.

The number average molecular weight of the polycarbonate polyurethane resin is 8000 or more. If the number average molecular weight is less than 8000, the mechanical strength, abrasion resistance, weather resistance, heat resistance, durability and the like of the top coat are insufficient. Preferred number average molecular weights are between 10,000 and 50,000. In order to obtain a top coat that can be used for high-temperature molding at 160 ° C or higher, the 100% modulus of polycarbonate-based polyurethane resin is
20 kgf / cm ² or more. If it is less than 20 kgf / cm ² , heat fusion occurs during molding or drawing, and the practicality is lost.

(B) (Meth) acrylates-butadiene-styrene resin (MBS resin) The term “(meth) acrylates” in the MBS resin refers not only to unsubstituted acrylates or methacrylates but also to acrylates or acrylates having a substituent. It should be understood to include methacrylate. As the substituent, an alkyl group is preferable. Such (meth) acrylates include:
Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth)
Acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, n-dodecyl (meth) acrylate and the like can be mentioned. Of these, methyl methacrylate is preferred. Styrene is not limited to unsubstituted styrene, but also includes substituted styrene such as α-methylstyrene.

MBS resin is commercially available as a high-temperature processing aid for polyvinyl chloride products, particularly as an additive for improving tensile strength and elongation at break during heating (for example, Metablen P-500 manufactured by Mitsubishi Rayon Co., Ltd.). , C-301 etc.). Commercial products according to the present invention can be used.

(C) Weight ratio The amount of the MBS resin added is 0.1 to 40 parts by weight based on 100 parts by weight of the polycarbonate polyurethane resin. MB
If the amount of the S resin is less than 0.1 part by weight, cracks occur in the top coat due to heat stretching (160 ° C.) of 150% or more. On the other hand, if it exceeds 40 parts by weight, the heat stretching is reduced, and the top coat is cracked by the heat drawing (160 ° C.) of 150% or more. The preferable addition amount of the MBS resin is 1 part by weight to 10 parts by weight.

(2) Thickness The thickness of the top coat is generally preferably 3 to 20 μm,
1515 μm is more preferred. If the thickness is less than 3 μm, embossing such as graining cannot be performed satisfactorily.
It is difficult to exceed μm.

[2] Production Method (A) Production of Thermoplastic Polyolefin Resin Sheet It is preferable that the thermoplastic polyolefin resin is melt-kneaded and formed into a sheet by extrusion molding or calender molding. Before applying the primer, the sheet is preferably subjected to a heat treatment or an ultraviolet irradiation treatment so as to be crosslinked. Crosslinking gives the sheet good heat resistance, weather resistance, durability, abrasion resistance, etc. without losing flexibility.

(B) Coating of Primer and Topcoat The coating of the primer and topcoat on the thermoplastic polyolefin resin sheet can be performed by a known method such as a roll coating method and a spraying method.

(D) Embossing To emboss the surface of the top coat or to form an aperture such as a leather pattern, embossing is applied.
The embossing process is performed at a temperature of 190 ° C. or more, preferably 190 to 240 ° C., particularly 190 to 210 ° C. from the surface of the top coat.

(E) Vacuum Forming The skin material of the present invention is suitable for use in interior parts such as instrument panels and is usually formed by vacuum forming. To this end, a foamed layer of polypropylene resin and a base sheet of polypropylene resin are respectively placed under the desired squeezed skin material via an olefin-based adhesive, and the whole is placed in a vacuum forming mold. I do. A vacuum is drawn from the substrate sheet side to form a predetermined shape. The vacuum forming temperature is preferably about 160 ° C.

[0040]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

In the examples, the following materials were used. (1) Thermoplastic elastomer sheet 0.6 mm thick, MFR (230 ° C, 2.16 kg load, JIS K7
210) is a thermoplastic elastomer sheet (polypropylene / olefin-based elastomer blend) of 1.04 g / 10 minutes. However, when applying a reactive primer, the surface of the sheet is subjected to corona discharge treatment before application, and the surface wetting index is set to 54dy.
Adjusted to n / cm.

(2) Primer and coating method AD-456M Chlorine-free modified polypropylene (carboxyl group content: 1.0 mg equivalent / g), a one-pack type primer (manufactured by Tokuso Shigyo Kogyo KK). L-4001 Chlorinated polypropylene primer (manufactured by Tokusekisho Kogyo Co., Ltd.). AD-180-9 / UA-63 Saturated polyester / polyisocyanate two-pack reaction type primer (weight ratio of AD-180-9 / UA-63 = 100/3, manufactured by Tokusetsu Kogyo Co., Ltd.). Coating method: One coating with a 120 mesh gravure roll coat (wet coating amount: 15 g / m ² ).

(3) Topcoat and coating method EK-167 Topcoat paint composed of saturated polyester, acrylic resin and polyvinyl chloride (weight ratio 30/60 /
10, Special Color Materials Co., Ltd.). EK-167 / UA-63 Saturated polyester, acrylic resin and polyvinyl chloride / polyisocyanate two-pack reaction type topcoat paint (EK-167 / UA-63 = 100/3, manufactured by Tokusetsu Kogyo Kogyo KK). HST-220 Polyurethane Topcoat Paint (Resin
100% modulus: 100 kgf / cm ² , Tokuseki Kogyo Co., Ltd.
Made). EU-470 Polyurethane topcoat paint (resin
100% modulus: 40kgf / cm ² , Tokusekisho Kogyo Co., Ltd.
Made). EU-105M Polyurethane Topcoat Paint (Resin
100% modulus: 60kgf / cm ² , Tokusekii Kogyo Co., Ltd.
Made). PEX5-12 Topcoat paint made of polycarbonate polyurethane resin (100% modulus of resin: 30kg
f / cm ² , manufactured by Tokusekisho Kogyo Co., Ltd.) Coating method: No. 40 bar coating method (wet coating amount: 50g /
m ^2).

Example 1 A primer (AD-456M) mainly composed of chlorine-free modified polypropylene was applied to each of the above thermoplastic elastomer sheets, and dried. As a top coat, a polycarbonate resin having a 100% modulus of 30 kgf / cm ² was used. A mixture of 0 to 100 parts by weight of an MBS resin and 100 parts by weight of a top coat paint (PEX5-12) mainly composed of a polyurethane resin was applied. The obtained skin material for heat molding (samples 1 to 16) was
The sample was heated and stretched at 0 ° C., and whether or not cracks occurred on the sample surface was tested and evaluated according to the following methods and criteria. Table 1 shows the results.

(1) Heat stretching test method Heating means and temperature: infrared heater (up to 160 ° C.) Unidirectional stretching ratio: 50% (1.5 times), 100% (2 times),
150% (2.5x), 200% (3x), 250% (3.5x)
Times), 300% (4 times)

(2) Evaluation Criteria ：: No cracks were observed by microscopic observation. ：: No cracks were observed by visual observation, but an average of 10 cracks with a length of 10 μm or less in a range of 40 mm ^{2 was} observed by microscopic observation.
Less than one was found. Δ: Microscopic observation revealed cracks exceeding the range of ○. ×: Cracks were clearly observed by visual observation. XX: Surface damage occurred due to cracks.

[0047]

[Table 1]

From the results in Table 1, it can be seen that the significant improvement of the heat drawing performance by the addition of MBS resin (possibility of heat drawing of 150% or more) is apparent from the addition of 0.1 parts by weight of MBS resin (sample 2) and that the addition of 40 parts by weight Part of MBS resin (sample
14) was clearly recognized. However, the addition of 50 parts by weight of MBS resin (sample 15) lost the effect, and the addition of 100 parts by weight of MBS resin (sample 16) adversely affected the stretching performance. Normally, the minimum draw ratio required to manufacture automobile interior parts is 150% (approximately 2x draw).
And the MB required to provide this draw ratio.
The mixing amount of the S resin is from 0.1 part by weight (sample 2) to 100 parts by weight of the polycarbonate polyurethane resin.
It is in the range of 40 parts by weight (sample 14). Another 300% (4
For a molded article requiring a stretching ratio of (double stretching), the range is preferably 1 part by weight (sample 7) to 10 parts by weight (sample 10).

Comparative Example 1 A commercially available chlorinated polypropylene-based primer (L-4001, sample 17) and a reactive primer (saturated polyester and polyisocyanate) were applied to each of the same thermoplastic elastomer sheets used in Example 1. AD-180-9 / UA-63
= 100/3, sample 18), and a primer mainly composed of chlorine-free modified polypropylene (AD-456M, sample 19). The top coat paint was not applied.
Each of the obtained samples 17 to 19 was stretched by heating at 160 ° C., and the same test as in Example 1 was carried out to evaluate whether or not cracks occurred on the sample surface. Table 2 shows the results.

[0050]

[Table 2]

From Table 2, it can be seen that the chlorinated polypropylene primer (Sample 17) and the chlorine-free modified polypropylene primer (Sample 19) were sufficiently heated and stretched (160 ° C.).
However, in the case of the two-liquid reaction system primer (sample 18), it was found that it was almost impossible to follow.

Comparative Example 2 A commercially available chlorinated polypropylene primer (L-4001) was applied to each of the same thermoplastic elastomer sheets used in Example 1. After drying, various commercially available top coats were applied. Each of the obtained samples was stretched by heating at 160 ° C., and the same test as in Example 1 was performed to evaluate whether or not cracks occurred on the sample surface. Table 3 shows the results.

[0053]

[Table 3]

As can be seen from Table 3, even when chlorinated polypropylene (L-4001) was used as a primer, a commercially available saturated polyester / acrylic resin-based top coat (sample 20) or a mixture thereof with a polyisocyanate (sample) 21) or using a polyurethane topcoat (samples 22 and 23), the resulting skin material was found to be unsuitable for thermoforming. Even if a high modulus polyurethane (100% modulus = 100 kgf / cm ² ) based top coat (HST220) is used (Sample 22), it can follow up to 50% stretch (1.5 times stretch), but it has better followability. Since it cannot be obtained, it cannot be used for ordinary molding applications.

Comparative Example 3 Each of the same thermoplastic elastomer sheets used in Example 1 was coated with a chlorine-free modified polypropylene primer (AD-4
56M), and after drying, various commercially available topcoats were applied. Each of the obtained samples was stretched by heating at 160 ° C., and the same test as in Example 1 was performed to evaluate whether or not cracks occurred on the sample surface. Table 4 shows the results.

[0056]

[Table 4]

From Table 4, it can be seen that even if a chlorine-free modified polypropylene primer (AD-456M) is used, a commercially available top coat (samples 24 to 27) containing no MBS resin can provide practical heat stretch moldability. I knew it wasn't. Also, it was found that even when a polyurethane-based top coat (EU105M) having a 100% modulus of 60 kgf / cm ² was used (sample 28), it could not be used for heat molding (160 ° C.). Sample 29 has a 100% modulus of 30 kgf / cm
^In the case where a top coat (PEX-512) made of polyurethane reduced to ² is used, 100% stretching (2.
It could be used up to 0-fold stretching, but there was no further followability.

[0058]

As described in detail above, the thermoplastic polyolefin resin skin material of the present invention is a polycarbonate polyurethane resin containing MBS resin on a thermoplastic polyolefin resin sheet via a chlorine-free modified polyolefin primer (number average). since the molecular weight is by applying a top coat paint for 100% modulus at 8000 or consisting 20 kgf / cm ² or higher), it has excellent heat stretchability formability, 150%
Even with the above heat stretching, cracks and breaks do not substantially occur on the surface. In addition, since all layers do not contain chlorine, the final product is a skin material having excellent solvent resistance without thermal discoloration and excellent recyclability.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) C09D 175/04 C09D 175/04 // C08J 7/04 CES C08J 7/04 CESB (72) Inventor Keiichi Honjo 1-4-1, Chuo, Wako-shi, Saitama Pref. Inside Honda R & D Co., Ltd. (72) Inventor Masami Imada 254-32 Nonoi, Toride-shi, Ibaraki Pref. F-term (Reference) 4F006 AA12 AB15 AB16 AB35 AB37 AB43 BA02 CA04 DA04 4F100 AK03A AK03B AK07A AK12C AK12J AK25C AK25J AK29C AK29J AK51C AK51E JA11A JA20C JB16A JK01 JK14 4J038 CP042 DG121 GA06 MA14 PA07 PB07 PC08

Claims (4)

[Claims] 1. A thermoplastic polyolefin resin sheet,
It has a chlorine-free modified polyolefin-based primer layer applied on the sheet, and a top coat layer applied on the primer layer, wherein the top coat layer has (a) a number average molecular weight of 8000 or more and 100% A thermoplastic polyolefin resin comprising, as main components, 100 parts by weight of a polycarbonate-based polyurethane resin having a modulus of 20 kgf / cm ² or more and (b) 0.1 to 40 parts by weight of (meth) acrylates-butadiene-styrene resin. Skin material. 2. The thermoplastic polyolefin resin skin material according to claim 1, wherein the primer is mainly composed of a polyolefin resin to which a hydroxyl group or a carboxyl group is added at 2 mg equivalent / g or less. Skin material. 3. The thermoplastic polyolefin resin skin material according to claim 1, wherein the polycarbonate-based polyurethane resin has a general formula:-[R ¹ -O- (CO) -0-] _n -R ^1-. O-CONH-R ² -NHCOO- (where R ¹ is an alkylene group, R ² is a polyisocyanate residue, and n is a structural unit of-[R ¹ -O- (CO) -0-]- A thermoplastic polyolefin resin skin material comprising: 4. The thermoplastic polyolefin resin skin material according to claim 1, wherein the thermoplastic polyolefin resin sheet is a thermoplastic elastomer composed of crystalline polypropylene and an olefin-based elastomer. Thermoplastic polyolefin resin skin material.