JP2001239548A - Method for manufacturing resin/metal composite molded object, and composite molded object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a resin/metal composite molded object wherein a resin part and a metal part are sufficiently interlocked without employing a complicated process. SOLUTION: When a thermoplastic elastomer composition is ejected on the surface of the metal part arranged in a mold to form the resin part, corona treatment or plasma treatment is applied to the whole or a part of the surface coming into contact with the resin part of the metal part before the metal part is arranged in the mold.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a resin / metal composite molded article having excellent adhesion between a resin part formed by injection molding of a thermoplastic elastomer composition and a metal part, for example, a cover-integrated gasket. On how to do it.

[0002]

2. Description of the Related Art In recent years, electronic devices such as computers have been improved in performance and miniaturization, and have complicated circuit structures. Even small amounts of dust can cause obstacles. In general, a gasket is sandwiched between joint surfaces of a box-shaped main body containing these electronic devices and a metal cover body and fastened with mounting bolts or the like to be hermetically integrated. I have. Further, in order to simplify handling during use, a cover-integrated gasket in which a gasket portion (resin portion) and a metal cover body are integrated is often used. The resin-metal composite molding such as the cover-integrated gasket is formed by a method of injecting a thermoplastic elastomer composition onto the surface of a metal component set in a mold to form a resin portion. If the part and the metal part are not sufficiently fixed, the resin part may be displaced or peeled off during the operation of removing the composite molded body from the mold (hereinafter, referred to as demolding).

Therefore, in order to fix the metal part and the resin part, the following method has conventionally been adopted.
All of these methods have complicated steps and require high production costs. A method in which an adhesive is applied in advance to the part of the metal part where the elastomer is to be injection-molded. How to lock

[0004]

SUMMARY OF THE INVENTION In view of the drawbacks of the conventional methods, the present invention provides a resin-metal composite molded article in which a resin part and a metal part are sufficiently fixed without going through complicated steps. It is intended to provide a method of making.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, all or a part of the surface of a metal part in contact with a resin portion has been subjected to corona treatment or plasma treatment. Later, it was found that the object could be achieved by installing it in a mold. The present invention has been completed based on such findings.

That is, according to the present invention, when forming a resin portion by injecting a thermoplastic elastomer composition onto the surface of a metal component placed in a mold, all or all of the portion in contact with the resin portion on the surface of the metal component. This is a method for producing a resin / metal composite molded body, which is characterized in that the molded body is placed in a mold after a corona treatment or a plasma treatment is performed on a part thereof. Attempts to corona-treat the resin side in order to improve the adhesion to metal include, for example, JP-A-11-235787 and JP-A-11-2629.
Although described at 78, corona treatment or plasma treatment on the metal side has never been attempted.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The corona treatment in the method of the present invention is not special, but is a corona discharge treatment usually performed for various purposes, and may be any of a spark gap system, a vacuum tube system, a solid state system and the like. The device is operational. The processing conditions are adjusted according to the equipment system and the like, and are not particularly limited. Further, the plasma treatment in the method of the present invention is not special,
Vacuum or normal pressure plasma discharge treatment usually performed for the purpose of various surface treatments, such as argon, oxygen, nitrogen, CF
₄ / Any gas such as oxygen and ethylene can be used.

The corona treatment or the plasma treatment does not need to be performed on the entire surface of the metal part, but may be performed on all or a part of the part which is in contact with the resin part formed by injection of the thermoplastic elastomer. 5 of the area of the part in contact with
It is preferably set to 0% or more.

The metal parts used in the method for producing a resin / metal composite molded article of the present invention are not particularly limited, and include, for example, cold-rolled steel sheets, galvanized steel sheets, aluminum / zinc alloy-coated steel sheets, stainless steel sheets, aluminum sheets. , Aluminum alloy plate, magnesium plate, magnesium alloy plate,
An electroless nickel-plated aluminum plate or the like can be appropriately selected and used according to the application. Further, a product obtained by injection-molding magnesium can also be used. From the viewpoint of corrosion resistance, a metal plate subjected to electroless nickel plating is preferable. As the electroless nickel plating method, there are known methods conventionally applied to metal materials, for example, pH 4.0 to 5.0 containing nickel sulfate, sodium hypophosphite, lactic acid, propionic acid and the like at an appropriate ratio. A method of immersing a metal plate in an electroless nickel plating bath consisting of an aqueous solution of about 0 and a temperature of about 85 to 95 ° C. can be used. When the resin-metal composite molded body is a cover-integrated gasket, the thickness of the metal plate is appropriately selected according to the use of the cover body, but is usually 0.3 to 1.0 m.
m, preferably in the range of 0.4 to 0.6 mm.

The thermoplastic elastomer used in the method for producing a resin / metal composite molded article of the present invention is not particularly limited. For example, styrene, olefin, urethane, and the like can be used.
Ester-based thermoplastic elastomers can be used. The present inventors have previously considered that (a) a vinyl aromatic compound-based material having excellent rubber elasticity, good oil retention, low hardness, excellent settability, and low compression set. A hydrogenated block copolymer obtained by hydrogenating a block copolymer comprising at least one of a united block and at least one of a polymer block mainly composed of a conjugated diene compound, and having a weight average molecular weight of 1
50,000 or more, wherein the polymer block mainly composed of a vinyl aromatic compound is polystyrene, and the polystyrene content in the hydrogenated block copolymer is 20 to 40.
100 parts by weight of a hydrogenated block copolymer,
(B) 50 to 200 parts by weight of a softener for a non-aromatic rubber having a kinematic viscosity at 40 ° C. of 300 mm ² s ⁻¹ or more, and (c) 5 to 50 parts by weight of a polyolefin resin containing polypropylene as a main component. (Japanese Patent Application No. 11-344879) has been proposed as a gasket material, and the thermoplastic elastomer composition and the component (c) of the thermoplastic elastomer composition are mainly made of polyethylene. A thermoplastic elastomer composition substituted with 5 to 50 parts by weight of a polyolefin resin as a component can also be suitably used in the method of the present invention.

The present inventors have further improved the adhesion of the thermoplastic elastomer composition to a metal by (a) at least one of a polymer block mainly composed of a vinyl aromatic compound and a conjugated diene. A hydrogenated block copolymer obtained by hydrogenating a block copolymer consisting of at least one polymer block mainly composed of a compound, having a weight average molecular weight of 200,000 or more and a vinyl aromatic compound (B) 40 parts by weight of a hydrogenated block copolymer in which the polymer block mainly composed of styrene is styrene, and the polystyrene content ratio in the hydrogenated block copolymer is 20 to 40% by weight. non-aromatic rubber softener 100 to 200 parts by weight of kinematic viscosity is 300 mm ² s ^-1 or more at ° C., and (c) modified polyolefin resin 10-50 fold A thermoplastic elastomer composition consisting of parts, 50 ° or less a type A durometer hardness is in conformity with JISK6253, JIS K6
70 ° C. under 25% compression, measured according to 262
A thermoplastic elastomer composition in which the compression set of the material after standing for a period of time is not more than 50% is proposed (Japanese Patent Application 2000).
However, this thermoplastic elastomer composition further enhances the effects of the present invention, and can be particularly preferably used.

In this thermoplastic elastomer composition having improved adhesion to metal, the hydrogenated block copolymer (a) is, for example, a block copolymer of polybutadiene and polystyrene, and a polyisoprene. It can be obtained by hydrogenating a block copolymer of polystyrene or a block copolymer of polybutadiene or an ethylene-butadiene random copolymer and polystyrene, and particularly, a styrene-butadiene-styrene block copolymer and styrene. -A hydrogenated block copolymer obtained by hydrogenating an isoprene-styrene block copolymer or a styrene-butadiene / isoprene-styrene block copolymer is preferable. Specifically, a diblock copolymer of crystalline polyethylene and polystyrene and a triblock copolymer of styrene-ethylene / butylene-styrene (S
EBS), triblock copolymer of styrene-ethylene / propylene-styrene (SEPS), styrene-ethylene propylene / ethylenebutylene-styrene block copolymer, and the like.
S, SEPS or styrene-ethylene propylene / ethylene butylene-styrene block copolymers are preferred.

The weight average molecular weight of these hydrogenated block copolymers is at least 200,000, and particularly preferably from 400,000 to 700,000. When the weight average molecular weight is less than 200,000, there is a disadvantage that the bleeding of the softening agent is remarkable, the compression set is large, and it cannot withstand practical use. The content of the (amorphous) styrene block of the hydrogenated block copolymer is as follows:
20 to 40% by weight. If the content is less than 20% by weight, the compression set becomes large, and if it exceeds 40% by weight, the hardness becomes too high.

The glass transition temperature (Tg) of the (amorphous) styrene block portion is desirably 60 ° C. or higher, preferably 80 ° C. or higher. As the polymer at the portion connecting the amorphous styrene blocks at both ends, an amorphous polymer is also preferable. For example, hydrogenated products such as ethylene-butylene copolymer, butadiene polymer, and isoprene polymer are preferable. And a block or random copolymer thereof. In addition, these hydrogenated block copolymers are mainly used alone, but two or more kinds may be blended and used. 2 with different molecular weight and styrene content
By blending more than one type of copolymer, the fluidity during molding can be improved. These hydrogenated block copolymers,
Easily obtainable from commercially available products such as Kuraray's Septon Series (trade name), Shell Chemical Co., Ltd.'s Clayton G Series (trade name), Asahi Kasei Corporation's Tuftec Series (trade name), etc. It is.

In the above-mentioned thermoplastic elastomer composition having improved adhesion to metal, the softener for non-aromatic rubber of component (b) is used to reduce the hardness of the resin composition of the present invention. The kinematic viscosity at 40 ° C is 30
Use a material of ⁰ mm ² s ⁻¹ or more. 40 of this softener
When the kinematic viscosity at 300 ° C. is less than 300 mm ² s ⁻¹ , the composition loses weight and bleeds significantly due to volatilization, resulting in a disadvantage that the composition cannot withstand actual use. The kinematic viscosity is 300 to 10 at 40 ° C. from practical and manufacturing points of view.
000 mm ² s ⁻¹ , especially 300 to
5000 mm ² s ⁻¹ is preferred. Further, from the viewpoint of molecular weight, the weight average molecular weight is less than 20,000, particularly 1000.
Those having a value of 0 or less, especially 5000 or less are preferred.
As such a softening agent, usually, a liquid or liquid at room temperature is suitably used. The softener having such properties can be appropriately selected from various softeners for non-aromatic rubbers such as mineral oils, vegetable oils, and synthetic oils. Here, mineral oils include naphthenic and paraffinic process oils, and vegetable oils include castor oil, cottonseed oil, linseed oil, rapeseed oil, and the like.
Examples include soybean oil, palm oil, nagiko oil, peanut oil, wood wax, pine oil and olive oil. Among them, one or two or more selected from mineral oil-based paraffinic oils, naphthenic oils, and synthetic polyisobutylene-based oils, and their number average molecular weight is 450 to 5
000 is preferred.

These softeners may be used alone or as a mixture of two or more as long as they have good compatibility with each other. The compounding amount of these softeners is 100 to 200 parts by weight, preferably 100 to 150 parts by weight, based on 100 parts by weight of the component (a). If the amount is less than 100 parts by weight, it is not possible to achieve a sufficiently low hardness, and the flexibility of the thermoplastic material may be insufficient. If the amount exceeds 200 parts by weight, the softener tends to bleed, and This causes the mechanical strength of the plastic material to decrease. The amount of the softener is appropriately selected from the above range according to the molecular weight of the hydrogenated block copolymer of the component (a) and the type of other components added to the hydrogenated block copolymer. Is preferred. These softeners include Diana Process Oil Series (trade name) manufactured by Idemitsu Kosan Co., Ltd., Sampar Series (trade name) and Sunsen Series (trade name) manufactured by Nippon Sun Oil Co., Ltd., and Lucant manufactured by Mitsui Chemicals, Inc. It can be easily obtained from those commercially available as a series (product name).

In the above-mentioned thermoplastic elastomer composition having improved adhesion to metal, the modified polyolefin resin as the component (c) is intended to improve processability and heat resistance and to improve adhesion to metal. It is blended for improvement. The modified polyolefin resin is preferably a resin mainly composed of polyethylene or polypropylene, and is preferably a copolymer of isotactic polypropylene, propylene and a small amount of other α-olefin (for example, propylene-ethylene copolymer). Combined, propylene / 4
-Methyl-1-pentene copolymer). When a copolymer of isotactic polypropylene is used as the polyolefin resin, its MFR
(According to JIS K7210, 230 ° C., under a load of 2.16 kg) in a range of 0.1 g / 10 min or more, especially 0.5 g / 10 min or more can be suitably used.

The modified polyolefin resin is obtained by polymerizing a polymerizable compound having a functional group on such a polyolefin resin. In particular, a functional group having an absorption band at a wave number of 1500 to 2000 cm ^-1 in an infrared absorption spectrum is used. Is preferred. In other words, according to the “Polymer Analysis Handbook” (Kinokuniya Shoten), the “characteristic absorption band” specific to polymer compositions is used as “application to qualitative analysis” of infrared analysis of polymer materials such as plastics and rubber. It has been found that there is a characteristic absorption band in the functional group of the polymer in the range of 1550 to 1950 cm ^-1 . For example, the absorption due to “carbonyl groups such as ketones, aldehydes and amides” “appears around 1700 cm ⁻¹ ”, and “in the case of esters, acid chlorides and acid anhydrides,
Absorption appears around 1850-1725 cm ^-1 on the higher wavenumber side, "and" 1610-10
It is described that there is an absorption band at "1550 cm ^-1 ". Furthermore, it is also described in detail that there is an absorption characteristic of "carbonyl in the 1750-1720 cm ^-1 region". Also,
With regard to the infrared absorption spectrum of polypropylene grafted with maleic anhydride, in particular, "C = O of maleic anhydride
Stretching vibrations appear around 1785 and 1860 cm ^-1 ". On the other hand, the infrared absorption spectrum of pure polypropylene described in the handbook has no infrared absorption in this region (1550 to 1950 cm ^-1 ). The present inventors have found that as a result of earnest research, 150
It has been found that a polyolefin-based resin having a functional group (maleic anhydride, acrylic acid, amide, carboxylate, etc.) having an absorption band in the range of 0 to 2000 cm ^-1 is preferable as the component (c).

The functional group having an absorption band in the range of 1500 to 2000 cm ^-1 is more preferably an unsaturated carboxylic acid, particularly one in the form of maleic anhydride or acrylic acid, and is an acid ester. It shows better adhesion than the ones. Examples of the polyolefin-based resin having such a functional group include, for example, Nuclell series (trade name) manufactured by Mitsui DuPont Polychemicals Co., Ltd., Umex series (trade name) manufactured by Sanyo Chemical Co., Ltd., and Exxon Chemical Co., Ltd. Commercially available products such as the Exeller series (trade name), the Polybond series (trade name) manufactured by Uniroyal Corporation, and the Admar series (trade name) manufactured by Mitsui Chemicals, Inc. can be used. The conversion rate (% by weight: 100 parts by weight of the modifying agent used with respect to polyethylene or polypropylene) is preferably 1% by weight or more in order to obtain sufficient adhesiveness. The amount of the component (c) is 10 to 50 with respect to 100 parts by weight of the component (a).
The amount is preferably 10 to 30 parts by weight.
If the amount is less than 10 parts by weight, the required adhesiveness cannot be obtained. If the amount exceeds 50 parts by weight, the hardness of the obtained thermoplastic material becomes too high. The resin composition of the present invention comprising these components (a), (b) and (c) has a hardness of JI.
5 with type A durometer based on SK6253
0 ° or less, measured according to JIS K6262
The material has a compression set of 50% or less after being left at 70 ° C. for 22 hours under 5% compression. If these conditions are not satisfied, the material is not suitable for use as a gasket material.

The thermoplastic elastomer composition used in the present invention includes clay, diatomaceous earth, talc, barium sulfate, calcium carbonate, magnesium carbonate, metal oxide,
Flaky inorganic additives such as mica, graphite, aluminum hydroxide, etc., various metal powders, glass powders, ceramic powders, granular or powdered solid fillers such as granular or powdered polymers, and other various natural or artificial additives Short fibers and long fibers (for example, glass fibers, metal fibers, and various other polymer fibers) can be blended.

Further, a hollow filler, for example, an inorganic hollow filler such as a glass balloon, polyvinylidene fluoride,
The weight can be reduced by blending an organic hollow filler composed of a polyvinylidene fluoride copolymer or the like. Further, in order to improve various physical properties such as weight reduction, it is possible to mix various foaming agents, and it is also possible to mechanically mix gas during mixing or the like.

As other additives, if necessary,
Various tackifiers such as flame retardants, antibacterial agents, hindered amine light stabilizers, ultraviolet absorbers, antioxidants, coloring agents, coumarone resins, coumarone-indene resins, phenol terpene resins, petroleum hydrocarbons, rosin derivatives, etc. Fire), Rheosummer B (trade name: manufactured by Riken Vinyl Co., Ltd.)
Various adhesive elastomers, such as HYBRA (trade name: Kuraray Co., a block copolymer in which polystyrene blocks are linked to both ends of a vinyl-polyisoprene block), Norex (trade name, manufactured by Zeon Corporation, norbornene) Other thermoplastic elastomers or resins such as polynorbornene obtained by ring-opening polymerization can be used in combination.

[0023]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The composition and physical properties of the thermoplastic elastomer composition used in the examples, and the methods of corona treatment and vacuum plasma treatment are as follows.

[Composition and Physical Properties of Thermoplastic Elastomer Composition] The weight average molecular weight is 350,000 and the polystyrene content is 30.
100 parts by weight of SEPS at least 40% by weight, 150 parts by weight of paraffinic oil having a kinematic viscosity at 380 mm ² s ^-1 at 40 ° C., and 25 parts by weight of maleic anhydride-modified polypropylene having a modification rate of 5% by weight are sufficiently kneaded. K
The hardness measured by a type A durometer is 25 ° according to 6253, and the permanent compression set after standing at 70 ° C for 22 hours under 25% compression is 3 according to JIS K6262.
0%.

[Corona treatment method] Equipment used: CORONA GENERATOR MODEL HV05-2 (manufactured by TANTEC) Electrode: electrode with a width of 80 mm Atmosphere: under air atmosphere Power: 100 W Time: 10 seconds

[Method of vacuum plasma treatment] Equipment used: glass vacuum device and high-frequency generator Atmosphere: under a gas atmosphere of 67 to 130 Pa Working gas: argon, oxygen, nitrogen, CF ₄ / oxygen, ethylene Power: 100 W Frequency: 13.56 MHz time: 300 seconds

Example 1 As shown in FIG. 1, a 15 mm × 30 m side having a square cross section having a width of 1 mm and a height of 1 mm was formed on a metal part 1.
A metal-integrated gasket in which a m-shaped resin molded body (gasket) 2 of m was formed was manufactured. As metal parts, one side 25mm x 40mm obtained by press working,
Using a rectangular aluminum plate having a thickness of 1 mm, a corona discharge treatment was applied to the entire surface on the side where the gasket was formed. Immediately after the corona discharge treatment, an aluminum plate was placed in a mold subjected to surface release treatment, and the thermoplastic elastomer composition was injected on the surface thereof at an injection temperature of 200 ° C and a time of 20 seconds from injection to demolding. Thus, a metal-integrated gasket was obtained. In the injection operation, the resin molded body did not peel off from the aluminum plate or deviated from the predetermined position at the time of demolding.

Example 2 Example 1 except that the material of the metal parts was changed to stainless steel.
However, in the injection operation, the resin molding did not peel off from the aluminum plate or deviated from the predetermined position at the time of demolding.

Example 3 The procedure was the same as that of Example 1 except that the processing method was changed to vacuum plasma processing in argon gas. However, in the injection operation, the resin molded product was peeled off from the aluminum plate during demolding. No displacement or deviation from the predetermined position occurred.

Example 4 The same procedure as in Example 1 was carried out except that the material of the metal parts was changed to stainless steel, and the processing method was changed to vacuum plasma processing in oxygen. The resin molded product did not peel off from the aluminum plate or deviated from the predetermined position at all.

Example 5 The same procedure as in Example 1 was carried out except that the processing method was changed to a vacuum plasma processing in CF ₄ / oxygen. There was no peeling from the sheet or no deviation from the predetermined position.

Example 6 The same procedure as in Example 1 was carried out except that the material of the metal part was changed to stainless steel and the processing method was changed to vacuum plasma processing in nitrogen. At this time, the resin molded product did not peel off from the aluminum plate or deviated from the predetermined position at all.

Example 7 The same procedure as in Example 1 was carried out except that the processing method was changed to vacuum plasma processing in ethylene gas. However, in the injection operation, the resin molded product was peeled off from the aluminum plate during demolding. No displacement or deviation from the predetermined position occurred.

[0034]

According to the present invention, it is possible to produce a resin-metal composite, such as a cover-integrated gasket, in which a resin part and a metal part are sufficiently fixed without going through complicated steps. it can. The cover-integrated gasket obtained by this method is suitably used, in particular, as a gasket material for a hard disk drive that requires high dustproofness.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a metal-integrated gasket, in which a cover and a gasket are integrated, prepared in an example.

[Explanation of symbols]

 1: Metal parts (cover) 2: Resin molding (gasket)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) C08L 53/02 C08L 53/02 // B29K 23:00 B29K 23:00 25:00 25:00 B29L 31: 34 B29L 31:34 (72) Inventor Tadashi Utsunomiya 2-20-24 Komachi, Kamakura-shi, Kanagawa F-term (reference) BB033 BB123 BB143 BB153 BB203 BB213 BP01X BP03X FD010 FD02W FD040 FD340 4J026 HD03 HD04 HD06 HD14 HE02

Claims (7)

[Claims] 1. A method for injecting a thermoplastic elastomer composition onto a surface of a metal component set in a mold to form a resin portion, wherein a corona is applied to all or a part of a portion of the metal component surface which is in contact with the resin portion. A method for producing a resin-metal composite molded body, comprising: installing the resin-metal composite in a mold after performing a treatment or a plasma treatment. 2. A thermoplastic elastomer composition comprising: (a)
A hydrogenated block copolymer obtained by hydrogenating at least one of a polymer block mainly composed of a vinyl aromatic compound and a block copolymer composed of at least one polymer block mainly composed of a conjugated diene compound. The weight average molecular weight is 150,000 or more, and the polymer block mainly composed of a vinyl aromatic compound is polystyrene, and the polystyrene content in the hydrogenated block copolymer is 20 to 40% by weight. % Of the hydrogenated block copolymer, and (b) a kinematic viscosity at 40 ° C. of 300 parts by weight.
mm ² s ⁻¹ or more, softener for non-aromatic rubber 50 to 2
25 parts by weight of not more than 50 ° with a type A durometer in accordance with JIS K6253, comprising 25 parts by weight of 00 parts by weight and (c) 5 to 50 parts by weight of a polyolefin resin containing polypropylene as a main component. The method for producing a resin-metal composite molded article according to claim 1, wherein the thermoplastic elastomer composition has a compression set of 50% or less after being left at 70 ° C for 22 hours under 30% compression. 3. A thermoplastic elastomer composition comprising: (a)
Low polymer block mainly composed of vinyl aromatic compounds
At least one polymer block mainly composed of a conjugated diene compound
Water into the block copolymer consisting of at least one of the locks
Hydrogenated block copolymer obtained by adding
Having a weight average molecular weight of 200,000 or more and a vinyl aromatic compound
Polymer block mainly composed of styrene and water
Polystyrene content in the block copolymer
Is a hydrogenated block copolymer 100 of 20 to 40% by weight.
Parts by weight, (b) kinematic viscosity at 40 ° C. is 300 mm^Twos
^-1The softener for non-aromatic rubber is 100 to 200 weight
Parts by weight, and (c) the modified polyolefin-based resin 10 to 50
It consists of parts by weight and its hardness complies with JIS K6253
Type A durometer of 50 ° or less, JIS K
70 ° C under 25% compression measured according to 6262, 2
Heatable with compression set of 50% or less after standing for 2 hours
Claims: It is a plastic elastomer composition.
2. The method for producing a resin-metal composite molded article according to 1. 4. The modified polyolefin resin (c) is a polyolefin resin containing polyethylene or polypropylene as a main component and a resin containing unsaturated carboxylic acids or acrylic acids. Method of making resin-metal composite molded article. 5. The method according to claim 4, wherein the unsaturated carboxylic acid is maleic anhydride. 6. A resin / metal composite molded article produced by the method according to claim 1. Description: 7. The resin-metal composite molded article according to claim 6, wherein the molded article is a cover-integrated gasket.