JP2002370312A - Composite molded object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite molded object wherein a resin layer comprising an olefinic resin and an elastic layer comprising a thermoplastic elastomer are integrally fused and both molded parts are strongly bonded. SOLUTION: The composite molded object is constituted by integrally fusing a resin layer, which uses a random block polypropylene copolymer based on propylene and containing an α-olefin other than propylene in a copolymerized amount of 3 mol % or more, and an elastic layer formed from a thermoplastic elastomer composition containing a specific amount of a specific hydrogenated block copolymer and a specific amount of a random polypropylene copolymer based on propylene and containing the α-olefin other than propylene in a copolymerized amount of 3 mol % or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thermoplastic elastomer composition containing a resin layer formed of a specific resin mainly composed of propylene, a specific styrene thermoplastic elastomer and a specific resin mainly composed of propylene. The present invention relates to a composite molded article in which an elastic layer formed of a composite material is integrally fused.

[0002]

2. Description of the Related Art Molded articles formed from olefin resins are used in a wide range of fields such as automobile parts, home electric appliance parts, toys, sporting goods and daily necessities.

On the other hand, a thermoplastic elastomer gives an elastic molded article by molding without requiring a vulcanizing step, and an elastic molded article formed from such a thermoplastic elastomer has been widely used in the same fields as described above. ing.

[0004] In order to make use of the features of each of the molded article made of the olefin resin and the elastic molded article made of the thermoplastic elastomer, it is generally practiced to compositely integrate them. Here, since the thermoplastic elastomer and the olefin-based resin are dissimilar materials, an adhesive may be used when the two are combined and integrated, or a mechanical surface treatment such as sandblasting or a corona discharge treatment may be applied to the joint between the two. Or by applying an electrical surface treatment such as an electrical surface treatment, or forming a fitting shape.

[0005] However, even when composite integration is performed using an adhesive, the bonding strength (bonding peel strength) at the interface between the portion formed by the thermoplastic elastomer and the portion formed by the olefin resin is not necessarily sufficient. Not big. Further, an organic solvent is usually used for the adhesive, and this organic solvent causes environmental pollution and the like.

[0006] On the other hand, in the case of performing composite surface integration by applying a mechanical surface treatment to the joint, since the thermoplastic elastomer and the olefin resin are not completely bonded,
There is a problem that the two are likely to be separated from each other, and that the shape of the molding die becomes complicated and that the manufacturing process becomes complicated.

As a solution to such a problem, there is a composite molded article obtained by integrally fusing a molded article made of polypropylene and an elastic molded article made of a styrene-based thermoplastic elastomer by a two-color molding method. Various proposals have been made.

For example, JP-A-2-139232 proposes a composite plastic molded article in which a polypropylene resin member and a thermoplastic elastomer member are both melted and integrated at an interface thereof.

According to JP-A-8-66990, an insert molding method for molding an olefin resin and then injection molding a styrene thermoplastic elastomer,
In the two-color injection molding method or the core back injection molding method, a method for producing a composite molded article using a hydrogenated product of a specific styrene / conjugated diene block copolymer as a styrene-based thermoplastic elastomer has been proposed.

[0010]

However, in the method of manufacturing a composite molded article or a composite molded article proposed in the past, the adhesive strength between the two members is not always sufficient, and further improvement in the adhesive strength is desired. .

An object of the present invention is to provide a composite molded article in which a resin layer composed of an olefin resin and an elastic layer composed of a thermoplastic elastomer are integrally fused, and both molded parts are firmly bonded. An object of the present invention is to provide a joined composite molded body.

[0012]

Means for Solving the Problems The present inventors have conducted intensive studies on the above problems, and as a result, have found that the olefin resin forming the resin layer is mainly composed of propylene and the copolymerization amount of α-olefin other than propylene is a specific amount. Select a certain random copolymerized polypropylene, a random copolymerized polypropylene having a specific hydrogenated block copolymer and propylene as the thermoplastic elastomer forming the elastic layer, and a copolymerized amount of α-olefin other than propylene being a specified amount. It has been found that a composite molded article in which both layers are integrally fused can be obtained by selecting a thermoplastic elastomer composition containing a specific amount of the above.

That is, the present invention provides a resin layer formed of a random copolymerized polypropylene mainly composed of propylene and having a copolymerization amount of α-olefin other than propylene of 3 mol% or more, and a polymer layer composed of an aromatic vinyl monomer. It has two or more coalesced blocks A and one or more polymer blocks B composed of a conjugated diene monomer, and at least 50% of carbon-carbon double bonds based on the conjugated diene monomer are hydrogenated to contain an aromatic vinyl monomer. 5% by mass or more 7
For 100 parts by mass of the hydrogenated block copolymer within a range of 5% by mass or less, 10% by mass of a random copolymerized polypropylene mainly composed of propylene and having a copolymerization amount of α-olefin other than propylene of 3% by mol or more. 1 parts by mass or more
An elastic layer formed from a thermoplastic elastomer composition contained in a range of not more than 00 parts by mass is a composite molded article integrally fused.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described more specifically.

The resin layer in the composite molded article of the present invention is a random copolymerized polypropylene (hereinafter referred to as a random copolymerized polypropylene (a)) mainly composed of propylene and having a copolymerization amount of α-olefin other than propylene of 3 mol% or more.
).

Here, α-olefins other than propylene include, for example, ethylene, butene-1, hexene-
1, ethylene or an α-olefin having 4 to 12 carbon atoms such as octene-1, and preferably ethylene or an α-olefin having 4 to 8 carbon atoms.

In the present invention, by using the random copolymerized polypropylene (a), the adhesive strength (adhesive strength) when the interface between the resin layer and the elastic layer is integrally fused can be increased. When a polypropylene copolymer or a homopolypropylene having a copolymerization amount of α-olefin of less than 3 mol% is used, sufficient adhesive strength is obtained even when the interface between the resin layer and the elastic layer is integrally fused. Not expressed. Even when the copolymerization amount of the α-olefin is 3 mol% or more, when the block copolymerized polypropylene is used, sufficient adhesive strength can be obtained even when the interface between the resin layer and the elastic layer is integrally fused. Can not get.

The copolymerization amount of the α-olefin in the random copolymerized polypropylene (a) is generally 13
It is at most 3 mol%, but preferably at least 3 mol% and at most 10 mol%.

The random copolymerized polypropylene (a) is usually used alone, but two or more kinds of α-olefins having different types or different amounts of copolymerization may be used in combination. In addition, the random copolymerized polypropylene (a) may have a filler, a heat stabilizer,
Antioxidants, light stabilizers, flame retardants, tackifiers, antistatic agents, foaming agents and the like can also be added.

Such a random copolymerized polypropylene (a) is formed into a sheet, film, rod, or any other three-dimensional shape by , for example, extrusion molding, injection molding, hollow molding, compression molding, calendar molding, or the like. be able to. In addition, the resulting molded product has mechanical strength,
It has properties such as heat resistance, oil resistance, and chemical resistance.

Next, the elastic layer in the composite molded article of the present invention has at least two polymer blocks A composed of an aromatic vinyl monomer and at least one polymer block B composed of a conjugated diene monomer. A hydrogenated block copolymer (hereinafter, referred to as hydrogenated) in which 50% or more of carbon-carbon double bonds based on a monomer are hydrogenated and the content of an aromatic vinyl monomer is in a range of 5% by mass to 75% by mass. A block copolymer (a), and a random copolymerized polypropylene (hereinafter, referred to as a random copolymerized polypropylene (c)) mainly composed of propylene and having a copolymerization amount of an α-olefin other than propylene of 3 mol% or more. Abbreviated).

First, the hydrogenated block copolymer (b) constituting the thermoplastic elastomer composition will be described.

The aromatic vinyl monomer constituting the polymer block A of the hydrogenated block copolymer (b) includes:
For example, styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 1,
Examples thereof include 3-dimethylstyrene, vinylnaphthalene, and vinylanthracene. Among them, styrene and α-methylstyrene are preferably used. The polymer block A may have a structural unit composed of only one of these aromatic vinyl monomers, or may have a structural unit composed of two or more types.

Examples of the conjugated diene monomer constituting the polymer block B include 1,3-butadiene,
Isoprene, 2,3-dimethyl-1,3-butadiene,
Examples thereof include 1,3-pentadiene and 1,3-hexadiene, and among them, isoprene, 1,3-butadiene or a mixture thereof is preferable. The polymer block B may be composed of one kind of these conjugated diene monomers, or may be composed of two or more kinds.

In the polymer block B, there is no restriction on the bonding mode of the conjugated diene unit, that is, the content of 3,4 bond and 1,2 bond (1,2 adduct and 3,4 adduct). The carbon-carbon double bond derived from the conjugated diene of the polymer block B needs to be hydrogenated. Here, the hydrogenation rate is determined by the required level of physical properties, and it is necessary that 50% or more of the carbon-carbon double bond derived from the conjugated diene be hydrogenated, and preferably 70% or more. And more preferably,
Preferably, 90% or more is hydrogenated. By setting the hydrogenation rate to 50% or more, the heat resistance of the thermoplastic elastomer is improved. When the hydrogenation rate is less than 50%, the heat resistance of the elastic layer formed of the thermoplastic elastomer composition is poor, and the composite molded article may be thermally degraded when manufactured.

The hydrogenation rate of the carbon-carbon double bond in the polymer block B in the hydrogenated block copolymer (b) can be determined, for example, by measuring the iodine value.
It can also be determined by measuring the amount of carbon-carbon double bonds using an infrared spectrophotometer, a nuclear magnetic resonance apparatus, or the like.

The content of the aromatic vinyl monomer in the hydrogenated block copolymer (b) is in the range of 5% by mass to 75% by mass, preferably 10% by mass to 65% by mass. When the content of the aromatic vinyl monomer exceeds 75% by mass, the hardness of the elastic layer is increased and its function is impaired. On the other hand, when the content is less than 5% by mass, the strength of the elastic layer is impaired and sufficient Adhesive strength is not exhibited.

Although the number average molecular weight of the hydrogenated block copolymer (b) is not particularly limited, it is generally from 30,000 to 3 from the viewpoint of moldability of the thermoplastic elastomer composition.
It is preferably in the range of not more than 00,000, and more preferably in the range of not less than 100,000 and not more than 200,000. Within this range, the obtained thermoplastic elastomer composition has an appropriate fluidity, and can easily and integrally fuse the elastic layer and the resin layer formed of the thermoplastic elastomer composition.

In the hydrogenated block copolymer (b), two or more polymer blocks A and one or more polymer blocks B are used.
The block copolymer is formed by bonding more than one polymer, but the bonding mode between the polymer block A and the polymer block B is not limited and may be linear, branched, or any combination thereof. Is also good.

The hydrogenated block copolymer (b)
Has a functional group or a substituent such as a carboxyl group, a hydroxyl group, an acid anhydride group, an amino group, an epoxy group, or a halogen atom in a side chain including a main chain or a terminal within a range not to impair the gist of the present invention. You may.

The method for obtaining the hydrogenated block copolymer (b) is not particularly limited. For example, a block copolymer is formed by sequentially polymerizing an aromatic vinyl monomer and a conjugated diene monomer in an inert organic solvent such as hexane or cyclohexane using an alkyl lithium compound as an initiator. Then, the obtained block copolymer is obtained by hydrogenation in an inert organic solvent in the presence of a hydrogenation catalyst according to a conventional method.

The hydrogenated block copolymer (b) can be widely obtained from commercial products. Specific examples thereof include "Septon", "Hibler" (both are trade names of Kuraray Co., Ltd.), "Clayton" (trade name of Clayton Polymer Co., Ltd.), and "Toughtec" (trade name of Asahi Kasei Corporation).

Next, the random copolymerized polypropylene (c) constituting the thermoplastic elastomer composition will be described.

The random copolymerized polypropylene (c) is
It is a random copolymerized polypropylene mainly composed of propylene and having a copolymerization amount of α-olefin other than propylene of 3 mol% or more.

Here, α-olefins other than propylene include, for example, ethylene, butene-1, hexene-
1, ethylene or an α-olefin having 4 to 12 carbon atoms such as octene-1, and preferably ethylene or an α-olefin having 4 to 8 carbon atoms.

In the present invention, a specific amount of a random copolymerized polypropylene (c) having a copolymerization amount of an α-olefin other than propylene of 3 mol% or more is blended in the thermoplastic elastomer composition, so that the elasticity of the elastic layer ( Flexibility,
While taking advantage of properties such as hardness) and mechanical strength, the bonding strength when the interface between the resin layer and the elastic layer is integrally fused can be increased.

When a polypropylene copolymer or homopolypropylene having a copolymerization amount of α-olefin of less than 3 mol% is used, sufficient adhesive strength is obtained even when the interface between the resin layer and the elastic layer is fused and integrated. Can not get. Also,
Even if the copolymerization amount of the α-olefin is 3 mol% or more,
When the block copolymerized polypropylene is used, a sufficient adhesive strength cannot be obtained even if the interface between the resin layer and the elastic layer is integrally fused. In addition, the copolymerization amount of the α-olefin in the random copolymerized polypropylene (c) is generally 13 mol% or less, but 3 mol% to 10 mol%.
The following is preferred.

The random copolymerized polypropylene (c) is
It may be the same as the random copolymerized polypropylene (a) used for the resin layer. Further, the random copolymerized polypropylene (c) may be used alone,
Two or more α-olefins having different types or different copolymerization amounts may be used in combination.

The amount of the random copolymerized polypropylene (c) is in the range of 10 parts by mass or more and 100 parts by mass or less based on 100 parts by mass of the hydrogenated block copolymer (b). If the amount is less than 10 parts by mass, the effect of improving the adhesive strength at the interface between the resin layer and the elastic layer of the obtained composite molded article is not sufficient. On the other hand, when the amount exceeds 100 parts by mass, it is difficult to make full use of favorable properties including the elasticity of the hydrogenated block copolymer (b). The preferred amount is from 20 parts by mass to 80 parts by mass.

The thermoplastic elastomer composition composed of the hydrogenated block copolymer (b) and the random copolymerized polypropylene (c) may contain a softener for non-aromatic rubber. Examples of the non-aromatic rubber softener include, for example, paraffin-based process oil, naphthene-based process oil, white oil, mineral oil, oligomers of ethylene and α-olefin, paraffin wax, liquid paraffin, and the like. Among them, a paraffinic process oil is preferable. These non-aromatic rubber softeners may be used alone or in combination of two or more.

When compounding a softener for non-aromatic rubber,
From the viewpoint of the mechanical strength of the elastic layer and the adhesive strength at the interface between the elastic layer and the resin layer, the amount is 100 parts by mass or less based on 100 parts by mass of the hydrogenated block copolymer (b). Preferably, there is. In particular, from 20 parts by mass to 8 parts by mass with respect to 100 parts by mass of the hydrogenated block copolymer (b).
By blending about 0 parts by mass, the properties such as flexibility of the elastic layer made of the thermoplastic elastomer composition can be maximized, and the adhesive strength with the resin layer can be improved.

The above thermoplastic elastomer composition includes:
A filler can be added as needed within a range that does not impair the purpose of the present invention. Examples of such a filler include calcium carbonate, talc, carbon black, titanium oxide, silica, clay, barium sulfate, magnesium carbonate, glass fiber, and carbon fiber.

The above thermoplastic elastomer composition includes:
Further, a heat stabilizer, an antioxidant, a light stabilizer, a flame retardant, a tackifier, an antistatic agent, a foaming agent, and the like can be added within a range that does not impair the purpose of the present invention. Further, other resins may be blended as needed, as long as the spirit of the present invention is not impaired. Examples thereof include olefin-based resins such as various polyethylenes and ethylene-propylene random copolymers other than the above-mentioned random copolymerized polypropylene (c).

[0044] Such a thermoplastic elastomer composition can be produced by a conventional method. In order to obtain a homogeneous composition, for example, it is desirable to knead each component in a heated and molten state using a kneader such as a single-screw extruder, a twin-screw extruder, a Banbury mixer, a Brabender, an open roll, or a kneader. . In this case, each component may be dry-blended using a mixer such as a Henschel mixer or a tumbler before melt-kneading.

The thermoplastic elastomer composition thus obtained is formed into a sheet, film, rod, or any other three-dimensional shape by, for example, extrusion molding, injection molding, hollow molding, compression molding, calendar molding, or the like. Can be molded. A molded article (elastic layer) molded from this thermoplastic elastomer composition has sufficient rubber elasticity, and its JIS A hardness is generally in the range of 40 to 95.

Next, a method for forming a composite molded body will be described.

In the composite molded article of the present invention, the method of forming the composite molded article is not limited as long as the resin layer and the elastic layer are integrally fused, and the shape thereof is not limited, and the shape of the composite molded article is not limited. Shape may be used. Resin layer in the present invention,
Since any resin or composition forming the elastic layer is thermoplastic, the resin layer and the elastic layer are manufactured by co-extrusion,
The resin layer and the elastic layer are integrally melted by manufacturing by normal injection molding to form a composite such as insert injection molding, two-color injection molding or core back injection molding, or by melt-compression bonding such as press molding. The attached composite molded body can be easily obtained.

Specifically, for example, a resin layer (or an elastic layer) previously formed into an arbitrary shape such as a sheet shape or a film shape is set in a mold of an injection molding machine capable of forming a desired shape. A method in which a thermoplastic elastomer composition (or a random copolymerized polypropylene (a)) is introduced into a mold in a molten state and molded to perform composite integration, a thermoplastic elastomer composition in a molten state and a random copolymerized polypropylene ( a) a method of coextruding a) by an extruder to form a composite and integrated, a method of melt-pressing an elastic layer and a resin layer previously formed into an arbitrary shape such as a sheet shape or a film shape by a press molding machine, and the like.

The composite molded body thus obtained has a feature that the elastic layer and the resin layer are integrally fused, and that the bonding strength at the interface between them is high.

The composite molded article obtained in this manner is a composite molded article in which members having different properties between a resin layer and an elastic layer are firmly joined, so that they can be used for industrial products, home appliances, and automobiles. It can be applied to a wide range of applications including those using conventional composite moldings such as interior and exterior parts, various grips, sports goods, leisure goods, toys and the like.
For example, sheets and films used in fields such as daily goods packaging, industrial material packaging, food packaging, and the like; hoses,
Tubes and belts; Footwear such as sports shoes and fashion sandals; Home appliances such as TVs, stereos and vacuum cleaners; Sealing packing used for window frames, etc .; Various grips for scissors, drivers, toothbrushes, ski poles, etc., underwater glasses, sports goods such as snorkels, leisure goods, toys and the like.

[0051]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Example 1 As a hydrogenated block copolymer (b), a hydrogenated block copolymer (b1) (trade name "Septon 4033", manufactured by Kuraray Co., Ltd., styrene- (isoprene / butadiene) -styrene triblock copolymer) Random copolymerized polypropylene (c) shown in Table 1 as a random copolymerized polypropylene (c) (trade name "J226TA" manufactured by Grand Polymer Co., Ltd.) using a styrene content of 30% by mass and a hydrogenation rate of about 100%). Was used.

[0053]

[Table 1]

100 parts by mass of a hydrogenated block copolymer (b1), 20 parts by mass of a random copolymerized polypropylene (c1), and a paraffinic process oil (trade name “Diana”) as a softener for a non-aromatic rubber as a softener 55 parts by mass of Process Oil PW-380 "manufactured by Idemitsu Kosan Co., Ltd.
Using a twin screw extruder (TEM-35B) manufactured by Toshiba Machine Co., the mixture was melt-kneaded at 230 ° C. and extruded to obtain a pellet-shaped thermoplastic elastomer composition.

On the other hand, using the same random copolymerized polypropylene (c1; trade name "J226TA" manufactured by Grand Polymer Co., Ltd.) as used in this thermoplastic elastomer composition,
A sheet piece (resin layer) having a length of 65 mm, a width of 25 mm and a thickness of 1 mm was formed by an injection molding machine (IS-55EPN manufactured by Toshiba Machine Co., Ltd.) set at a cylinder temperature of 230 ° C and a mold temperature of 60 ° C.

Then, a mold for providing a molded product having the same length and width as the sheet piece and a thickness of 2 mm was attached to the above-mentioned injection molding machine (IS-55EPN manufactured by Toshiba Machine Co., Ltd.). The resin layer) was inserted into this mold.
The cylinder temperature was set to 230 ° C., the mold temperature was set to 60 ° C., and the thermoplastic elastomer composition obtained as described above was injection molded to obtain a composite molded article. This composite molded body has a length of 65 mm, a width of 25 mm, a thickness of 2 mm, and a thickness of 1 mm
And the elastic layer having a thickness of 1 mm were integrally fused at the interface of the joint.

For the obtained composite molded product, the surface hardness of the elastic layer formed from the thermoplastic elastomer composition was determined by J
According to IS K6301, it was 57 when measured using an A type spring hardness tester, and it was confirmed that the rubber had sufficient rubber elasticity.

Next, the adhesive strength of the joint between the elastic layer and the resin layer of the composite molded body was subjected to a tensile test at a rate of 50 mm / min using an Instron universal testing machine, and peeling at the joint was performed. The required maximum load was evaluated by the adhesive peel strength divided by the width of the joint. The obtained adhesive peel strength was 10.5.
(Kg / 25 mm width), which was a practically extremely high value.

COMPARATIVE EXAMPLES 1 AND 2 Block copolypropylene (c2) shown in Table 1 (Comparative Example 1) and homopolypropylene shown in Table 1 were used in place of the random copolymerized polypropylene (c1) as a sheet piece for forming the resin layer. (C3) Using (Comparative Example 2) and the same injection molding machine (IS-55EPN manufactured by Toshiba Machine Co., Ltd.) under the same conditions as in Example 1 under the same conditions as in Example 1, the length is 65 mm and the width is 25.
mm and a 1 mm-thick sheet piece (resin layer) were formed.

Then, the same mold as that used in Example 1 was mounted on the same injection molding machine (IS-55EPN manufactured by Toshiba Machine Co., Ltd.) as in Example 1, and the obtained sheet piece was inserted into this mold. The cylinder temperature was set to 230 ° C., the mold temperature was set to 60 ° C., and the same thermoplastic elastomer composition used in Example 1 was injection molded to obtain a composite molded article.

With respect to the obtained composite molded article, the surface hardness of the elastic layer formed from the thermoplastic elastomer composition and the adhesive peel strength of the joint between the elastic layer and the resin layer of the composite molded article were the same as those in Example 1. Was measured under the following conditions. The results are shown in Table 2 together with the results of Example 1.

[0062]

[Table 2]

The adhesive peel strength of the composite molded article obtained in Comparative Example 1 was 7.3 (kg / 25 mm width), and the adhesive peel strength of the composite molded article obtained in Comparative Example 2 was 6.1 (kg / 25 mm). kg
/ 25 mm width). Thus, if the block copolymerized polypropylene (c2) is used instead of the random copolymerized polypropylene (c1) as the resin constituting the resin layer, or if the homopolypropylene (c3) is used, sufficient adhesive strength cannot be obtained. You can see that.

Comparative Examples 3 to 5 In Examples 1 and Comparative Examples 1 and 2, the block copolymerized polypropylene (c2) shown in Table 1 was used in place of the random copolymerized polypropylene (c1) constituting the thermoplastic elastomer composition. Example 1 and Comparative Examples 1 and 2 except for
After obtaining the composite molded body in the same manner as in Example 1, the hardness of the elastic layer and the adhesive peel strength of the joint between the elastic layer and the resin layer were measured in the same manner as in Example 1. The results were obtained in Example 1 and Comparative Examples. The results are shown in Table 2 together with

The adhesive peel strength of the composite molded product obtained in Comparative Example 3 was 7.2 (kg / 25 mm width), and the resin to be blended with the thermoplastic elastomer composition constituting the elastic layer was made of random copolymerized polypropylene. It can be seen that sufficient adhesive strength cannot be obtained by using block copolymerized polypropylene instead.

The adhesive-peel strength of the composite molded article obtained in Comparative Example 4 was 6.3 (kg / 25 mm width), and it was determined that the composite molded article had a resin constituting the resin layer and a thermoplastic elastomer composition constituting the elastic layer. When the block copolymerized polypropylene was used instead of the random copolymerized polypropylene as the resin to be blended, it can be seen that the adhesive strength was further reduced as compared with Comparative Example 1 or Comparative Example 3.

The adhesive peel strength of the composite molded product obtained in Comparative Example 5 was 5.5 (kg / 25 mm width), and homopolypropylene was used instead of the block copolymerized polypropylene as the resin to be mixed with the resin constituting the resin layer. By using
It can be seen that the adhesive strength is further reduced as compared with Comparative Example 4.

Comparative Examples 6 to 8 In Examples 1 and Comparative Examples 1 and 2, the homopolypropylene (c) shown in Table 1 was used in place of the random copolymerized polypropylene (c1) constituting the thermoplastic elastomer composition.
After obtaining a composite molded body in the same manner as in Example 1 and Comparative Examples 1 and 2 except that 3) was used, the hardness of the elastic layer and the joint of the elastic layer and the resin layer were measured in the same manner as in Example 1. The adhesive peel strength was measured, and the results are shown in Table 2 together with Example 1 and Comparative Examples.

The peel strength of the composite molded product obtained in Comparative Example 6 was 6.8 (kg / 25 mm width), and the resin to be blended with the thermoplastic elastomer composition constituting the elastic layer was made of random copolymerized polypropylene. It can be seen that sufficient adhesive strength cannot be obtained by using homopolypropylene instead.

The adhesive peel strength of the composite molded product obtained in Comparative Example 7 was 6.3 (kg / 25 mm width), and block copolymer was used instead of random copolymerized polypropylene as the resin to be mixed with the resin constituting the resin layer. It can be seen that the use of the polymerized polypropylene further reduced the adhesive strength as compared with Comparative Example 6.

Further, the adhesive peel strength of the composite molded article obtained in Comparative Example 8 was 5.3 (kg / 25 mm width), and the resin constituting the resin layer and the thermoplastic elastomer composition constituting the elastic layer were not used. It can be seen that when homopolypropylene was used instead of random copolymerized polypropylene as the resin to be blended, the adhesive strength was further reduced as compared with Comparative Example 2 or Comparative Example 6.

[0072]

According to the present invention, there is provided a composite molded article in which a resin layer composed of an olefin resin and an elastic layer composed of a thermoplastic elastomer are integrally fused, and both molded parts are firmly joined. The composite molded article which has been obtained can be provided.

(72) Inventor Shigeru Kawahara 41 Miyukigaoka, Tsukuba, Ibaraki Pref. Kuraray Co., Ltd. (72) Inventor Masao Ishii 1-12-39 Umeda, Kita-ku, Osaka-shi, Osaka Kuraray F Term (reference) 4F100 AJ11 AJ11H AK07B AK12B AK28B AK66A AL01B AL03A AL03B AL05B AL09B BA02 EC03 EC033 GB33 GB48 GB71 GB81 GB87 JB16B YY00A YY00B

Claims (2)

[Claims] 1. A resin layer formed of random copolymerized polypropylene mainly composed of propylene and having a copolymerization amount of α-olefin other than propylene of 3 mol% or more, and a polymer block A composed of an aromatic vinyl monomer. A carbon block based on a conjugated diene monomer, having at least one polymer block B comprising at least two and a conjugated diene monomer;
At least 50% of the carbon double bond is hydrogenated, and propylene is mainly used for 100 parts by mass of the hydrogenated block copolymer in which the content of the aromatic vinyl monomer is in the range of 5% by mass to 75% by mass. And an elastic layer formed from a thermoplastic elastomer composition containing 10 to 100 parts by mass of a random copolymerized polypropylene having a copolymerization amount of an α-olefin other than propylene of 3% by mol or more. , Are integrally fused. 2. A resin layer formed of a random copolymerized polypropylene mainly composed of propylene and having a copolymerization amount of α-olefin other than propylene of 3 mol% or more, and a polymer block A composed of an aromatic vinyl monomer. A carbon block based on a conjugated diene monomer, having at least one polymer block B comprising at least two and a conjugated diene monomer;
At least 50% of the carbon double bond is hydrogenated, and propylene is mainly used for 100 parts by mass of the hydrogenated block copolymer in which the content of the aromatic vinyl monomer is in the range of 5% by mass to 75% by mass. And an elastic layer formed from a thermoplastic elastomer composition containing 10 to 100 parts by mass of a random copolymerized polypropylene having a copolymerization amount of α-olefin other than propylene of 3 mol% or more. , Wherein the joint between the resin layer and the elastic layer is joined by heat fusion.