JP2003001761A - Polyacetal resin / thermoplastic elastomer composite molded article and molding method thereof - Google Patents

Abstract

(57) [Problem] To provide a composite molded article in which the fusion property at the interface between the molded article part made of a polyacetal resin and the molded article part made of a thermoplastic elastomer is improved. SOLUTION: Polyacetal (co) polymer (A1) 9
9.9 to 0% by weight, and 1 to 200 mmol in the molecule
/ Kg of modified polyacetal (co) polymer having carboxyl group / (A2) 0.1 to 100% by weight of polyacetal resin (A) (the sum of A1 and A2 is 100% by weight) A composite molded article obtained by fusing with a molded article portion made of a thermoplastic elastomer (B).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite in which a molded body part made of a thermoplastic elastomer is fused to a molded body part made of a polyacetal resin containing a modified polyacetal (co) polymer having a carboxyl group in the molecule. The present invention relates to a molded body and a molding method thereof. The composite molded article is excellent in fusion bonding between the molded body part made of the polyacetal resin and the molded body part made of the thermoplastic elastomer.

[0002]

2. Description of the Related Art Polyacetal (POM) resin, which is a type of engineering plastic, has excellent properties such as mechanical properties, thermal properties, electrical properties, slidability, and moldability. Widely used as materials and mechanical parts for electric / electronic devices, automobile parts, office equipment parts, daily sundries parts, etc. On the other hand, thermoplastic elastomers are excellent in flexibility, water resistance, cold resistance, etc. and are used in many applications. Known thermoplastic elastomers of this type include styrene-based, polyolefin-based, polyester-based, polyurethane-based and the like. The injection molding method is capable of molding even molded products with complicated shapes and is suitable for mass production.The injection molding method is applied to the above-mentioned polyacetal resin and thermoplastic elastomer, and various mechanical parts can be efficiently used. It is manufactured, or an elastomer molded body is molded with particularly high productivity. In recent years, demands for high performance and high functionality of synthetic resin (plastic) parts and members have become strict, and among them, attention has also been paid to the combination of engineering plastics and thermoplastic elastomers. Then, for compounding, it is most effective to heat-bond the two to each other (also simply referred to as fusion-bonding) by an injection molding method which is a molding means common to both.

However, in general, the thermal fusion bond between a thermoplastic engineering plastic and a thermoplastic elastomer is not always good. In particular, polyacetal resin has high crystallinity, poor surface activity, and low affinity with other resins, so that a composite molded product with a thermoplastic elastomer cannot obtain sufficient adhesive strength and fusion strength at the joint surface. There is a problem. Therefore, when trying to manufacture a composite molded body such as a high-value-added composite part or composite member by compositing a polyacetal resin and a thermoplastic elastomer, for example, by providing an uneven engaging portion at the joint between the two, mechanically Non-productive joining such as joining method, roughening the joining surface of polyacetal resin molded product side by flame treatment or hot air treatment or applying functional group, or applying adhesive to both joints Under the present circumstances, it is unavoidable to adopt a method or a method whose surface is easily deteriorated. For example, the method of mechanically joining by providing the above-mentioned concave and convex engaging portions,
There is a problem that the mold structure becomes complicated, or the number of steps increases depending on the structure. Further, it may not be possible to form a strong bond structure in view of the shape of the final composite molded body. In addition, the joining method using an adhesive may require a step such as application of the adhesive, and the adhesive strength may deteriorate due to deterioration of the adhesive.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems and to melt the interface between a molded body part made of a polyacetal resin having improved fusion bondability and a molded body part made of a thermoplastic elastomer. The object is to provide a composite molded article having improved adherence.

[0005]

Means for Solving the Problems In order to obtain a composite molded article having improved fusion bondability and adhesiveness between a polyacetal resin and a thermoplastic elastomer, the inventors of the present invention have selected a specific component during synthesis of the polyacetal resin. It was presumed that the key to the solution of the problem was to modify the polymer skeleton by adding and copolymerize it to give these properties to the polymer itself. As a result of intensive studies, the present inventors have made a polyacetal resin containing a modified polyacetal (co) polymer in which a compound having a carboxyl group and an alcoholic hydroxyl group in one molecule is copolymerized to introduce a carboxyl group into the polymer skeleton. By using, it has been found that the above-mentioned problems can be solved, and that a molded body part made of a polyacetal resin and a molded body part made of a thermoplastic elastomer can be firmly fused, and the present invention has been completed. .

That is, the first aspect of the present invention is that the polyacetal (co) polymer (A1) is 99.9 to 0% by weight, and the modified polyacetal (co) polymer (having a carboxyl group of 1 to 200 mmol / kg in the molecule ( A2) 0.1-1
Composite molding in which a molded body part made of a polyacetal resin (A) made up of 00% by weight (the total of A1 and A2 is 100% by weight) and a molded body part made of a thermoplastic elastomer (B) are fused. Provide the body. Second of the present invention
Is a cyclic oligomer of formaldehyde in which the polyacetal (co) polymer (A1) is represented by formaldehyde or general formula (CH ₂ O) n [where n is an integer of 3 or more] (formula derivative (a )) Or by copolymerizing the formaldehyde derivative (a) with a comonomer (c) consisting of a cyclic ether and / or a cyclic formal. A composite molded article of No. 1 is provided. The third aspect of the present invention is modified polyacetal (co).
The polymer (A2) homopolymerizes the formaldehyde derivative (a) in the presence of the compound (b) having a carboxyl group and an alcoholic hydroxyl group in one molecule, or the formaldehyde derivative (a) and the comonomer (c). The present invention also provides the first or second composite molded article of the present invention, which is a modified (co) polymer obtained by copolymerizing In a fourth aspect of the present invention, the compound (b) is glycolic acid, lactic acid, α-oxyisobutyric acid, β-oxyisobutyric acid, oxypivalic acid, 1
There is provided a third composite molded article of the present invention, which is at least one selected from the group consisting of 2-oxystearic acid, malic acid, citric acid, glyceric acid, and tartaric acid. A fifth aspect of the present invention provides the composite molded article according to any one of the first to fourth aspects of the present invention, wherein the thermoplastic elastomer (B) is a polar group-containing thermoplastic elastomer. A sixth aspect of the present invention provides the fifth composite molded article of the present invention, wherein the thermoplastic elastomer having a polar group is a polyester thermoplastic elastomer (B1). A seventh aspect of the present invention provides the composite molded article according to any one of the first to fourth aspects of the present invention, wherein the thermoplastic elastomer (B) contains 20% by weight or more of the polyester thermoplastic elastomer (B1). To do. In the eighth aspect of the present invention, the thermoplastic elastomer (B) is 100 parts by weight of the polyester-based thermoplastic elastomer (Bl) and 0 in total of the styrene-based thermoplastic elastomer (B2) and / or the olefin-based thermoplastic elastomer (B3). To 400 parts by weight of the composite molded article according to any one of the first to fourth aspects of the present invention. The ninth aspect of the present invention is the polyacetal resin (A) according to any one of the first to fourth aspects of the present invention and the first aspect of the present invention.
And the thermoplastic elastomer (B) according to any one of 5 to 8
The present invention provides a method for molding a composite molded body, which comprises performing two-color injection molding. The tenth aspect of the present invention is the first to fourth aspects of the present invention.
After placing the primary molded article composed of the polyacetal resin (A) shown in any one of the above items in a mold, the thermoplastic elastomer (B) shown in any one of the first and fifth to eight aspects of the present invention is used. Subsequent injection molding, or after placing a primary molded article comprising the thermoplastic elastomer (B) shown in any of the first and fifth to eighth aspects of the present invention in a mold, the first to first aspects of the present invention A ninth aspect of the present invention provides a molding method for a composite molded article of the present invention, which comprises subjecting the polyacetal resin (A) shown in any one of No. 4 to secondary injection molding. 11th of the present invention
Is a primary molded product made of polyacetal resin (A).
The second aspect of the present invention is characterized in that the thermoplastic elastomer (B) is secondarily injection-molded at a temperature equal to or higher than the melting point of the polyacetal resin (A) after being placed in a mold in a state of being preheated to 0 ° C. or higher. A method for molding a composite molded article according to 10, is provided.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. I. Polyacetal resin (A) The polyacetal resin (A) used in the present invention comprises a modified polyacetal (co) polymer (A2) and a polyacetal (co) polymer (A1) used as necessary.

Polyacetal (co) polymer (A1) The above-mentioned polyacetal (co) polymer (A1) which is optionally used is a usual polyacetal homopolymer or polyacetal copolymer. That is, the polyacetal (co) polymer (A1) has an oxymethylene group (—CH
₂ O-) is a high molecular compound whose main constituent unit is a polyoxymethylene homopolymer, a copolymer containing other constituent units in addition to the oxymethylene group (copolymers include random, block and mixed structures thereof), It may be any polymer, and the molecule may have not only a linear structure but also a branched or crosslinked structure. When there is no need to distinguish between polyoxymethylene homopolymer, copolymer and terpolymer, it is simply referred to as polyacetal.

Polyacetal Homopolymer Generally, polyacetal homopolymer is produced by polymerizing formaldehyde derivative (a). Specific examples of the formaldehyde derivative (a) include anhydrous formaldehyde, trioxane which is a cyclic triplet of formaldehyde represented by the general formula (CH ₂ O) n [where n is an integer of 3 or more], and the like. .

Polyacetal Copolymer The polyacetal copolymer has a repeating group (--CH ₂ O--).
And the following general formula (i):

[Chemical 1] (In the formula, R ¹ and R ² are each selected from the group consisting of hydrogen, lower alkyl and halogen-substituted lower alkyl groups, and two R ¹ or R ² may be different from each other; R ³ is Selected from the group consisting of alkylene, oxyalkylene, lower alkyl and haloalkyl substituted methylene, and lower alkyl and haloalkyl substituted oxyalkylene groups, m is an integer of 0 to 3, and each lower alkyl group has 1 to 2 carbon atoms. When there are a plurality of repeating groups (i) in the polymer chain, the repeating group (i) represented by the repeating groups (i) may be the same or different. Or, it has a structure existing in a block. The polyacetal copolymer is generally obtained by copolymerizing the formaldehyde derivative (a) and the comonomer (c). Examples of the comonomer (c) include cyclic ether and cyclic formal, and specifically, ethylene oxide, propylene oxide, butylene oxide, epichlorohydrin, epibromohydrin, styrene oxide, oxetane,
Cyclic ethers such as 3,3-bis (chloromethyl) oxetane, tetrahydrofuran, trioxepane, and 1,3-dioxolane; and propylene glycol formal.
Diethylene glycol formal, triethylene glycol formal, 1,4-butanediol formal,
Examples include cyclic formal such as 1,5-pentanediol formal and 1,6-hexanediol formal. You may mix and use these. Of these, ethylene oxide, 1,3-dioxolane, diethylene glycol formal and 1,4-butanediol formal are preferable. The amount of the comonomer (c) used is, considering the rigidity and chemical resistance of the obtained polyacetal copolymer,
1 to 100 parts by weight of formaldehyde derivative (a)
It is 0 to 20 parts by weight, preferably 0.01 to 15 parts by weight, and particularly preferably 0.1 to 10 parts by weight in total of one kind or two or more kinds.

In the production of the polyacetal, a polyfunctional compound capable of forming a conventional branched / crosslinked compound such as a diglycidyl ether compound or the like is polymerized by using a molecular weight adjusting component such as methylal in combination. In addition, it is also possible to polymerize. Examples of the molecular weight adjusting component include conventionally known low molecular weight acetal compounds and the like, and specifically include an alkoxy group such as methylal, methoxymethylal, dimethoxymethylal, trimethoxymethylal, and oxymethylenedi-n-butyl ether. And compounds having the same.

The above-mentioned polyacetal is produced in the presence of a catalyst. As the catalyst, a cationic polymerization catalyst is generally used, and specific examples thereof include lead tetrachloride, tin tetrachloride, titanium tetrachloride, aluminum trichloride, zinc chloride, vanadium trichloride, antimony trichloride, phosphorus pentafluoride, and pentapentane. Antimony fluoride, boron trifluoride, boron trifluoride diethyl etherate, boron trifluoride dibutyl etherate, boron trifluoride dioxanate, boron trifluoride acetic unhydrate, boron trifluoride triethylamine complex compound, etc. Boron trifluoride coordination compound, perchloric acid, acetyl perchlorate, t-butyl perchlorate, hydroxyacetic acid, trichloroacetic acid, trifluoroacetic acid, p
-Inorganic and organic acids such as toluenesulfonic acid, triethyloxonium tetrafluoroborate, triphenylmethyl hexafluoroantimonate, allyldiazonium hexafluorophosphate, complex salt compounds such as allyldiazonium tetrafluoroborate, diethyl zinc, triethylaluminum, diethyl Alkyl metal salt such as aluminum chloride, heteropoly acid, isopoly acid, etc. 1
Or two or more species. Among them, boron trifluoride,
Boron trifluoride coordination compounds such as boron trifluoride diethyl etherate, boron trifluoride dibutyl etherate, boron trifluoride dioxanate, boron trifluoride acetic unhydrate, and boron trifluoride triethylamine complex compound are preferable. . These cationic polymerization catalysts can be used as they are or after being diluted with an organic solvent or the like in advance, and the preparation method is not particularly limited.

The method for producing the polyacetal is not particularly limited, but generally, liquefied trioxane and the comonomer (c) are bulk polymerized using a catalyst to obtain a solid powder lump polyacetal. . The polymerization device is not particularly limited, a known device is used,
Any method such as a batch method or a continuous method is possible. The polymerization temperature is preferably maintained at 65 to 135 ° C.

Deactivation of the catalyst in the polyacetal after polymerization is carried out by adding a basic compound or an aqueous solution thereof to the reaction product discharged from the polymerization machine after the polymerization reaction or the reaction product in the polymerization machine. . Examples of the basic compound for neutralizing and deactivating the polymerization catalyst include ammonia, amines such as triethylamine, tributylamine, triethanolamine, tributanolamine, and hydroxide salts of alkali metals and alkaline earth metals. Other known catalyst deactivators are used. Further, it is preferable to rapidly add these aqueous solutions to the product to deactivate it after the polymerization reaction. After the polymerization method and the deactivation method, washing, separation and recovery of unreacted monomers, drying and the like are further performed by a conventionally known method, if necessary. The obtained polyacetal is
Further, if necessary, stabilization treatment is carried out by a known method such as decomposition and removal of unstable terminal portions by hydrolysis or sealing of unstable terminals by a stable substance.

The polyacetal has a melt index of 0.1 to 1,000 g / lOmin, preferably 0.2 to 500 g / lOmin.

Various stabilizers such as an antioxidant, a heat resistance stabilizer (decomposition inhibitor), a weather resistance (light) stabilizer and the like are usually added to the polyacetal. Examples of the various stabilizers include hindered phenol compounds, nitrogen-containing compounds, alkali or alkaline earth metal hydroxides, inorganic salts, carboxylates, and the like. These may be used alone or in combination of two or more. Good.

Modified polyacetal (co) polymer (A2) Next, the modified polyacetal (co) polymer (A2) used in the present invention is one in which a carbocycle group is introduced into the polyacetal molecule, for example, as described above. In the production of a novel polyacetal homopolymer or copolymer, 1
Obtained by adding a compound (b) having a carboxyl group and an alcoholic hydroxyl group in the molecule and polymerizing it, or by reacting the compound (b) with the end of the polyacetal, and preferably obtained by the former method. Is.

Examples of the compound (b) having a carboxyl group and an alcoholic hydroxyl group in one molecule include an aliphatic oxycarboxylic acid, an alicyclic oxycarboxylic acid, an aromatic oxycarboxylic acid, and the like. Carboxylic acids are preferred. Specific examples of the aliphatic oxycarboxylic acid include monooxymonocarboxylic acid, monooxydicarboxylic acid, monooxytricarboxylic acid, dioxymonocarboxylic acid, dioxydicarboxylic acid, dioxytricarboxylic acid, trioxymonocarboxylic acid. , Trioxydicarboxylic acid, trioxytricarboxylic acid and the like. Of these, particularly preferred are glycolic acid, which is one type of monooxycarboxylic acid, lactic acid, α-oxyisobutyric acid, β-oxyisobutyric acid, oxypivalic acid, 12-oxystearic acid, and malic acid which is one type of monooxydicarboxylic acid, Alternatively, it is citric acid, which is a type of monooxytricarboxylic acid, glyceric acid, which is a type of dioxymonocarboxylic acid, and tartaric acid, which is a type of dioxydicarboxylic acid.

Modified polyacetal (co) polymer (A2)
Can be polymerized by adding a lactone (b ′) if necessary. Examples of the lactone (b ′) include β-propiolactone, δ-valerolactone, ε-caprolactone, α
-Oxy-γ-butyrolactone and the like can be mentioned. As a result, it is possible to improve the fusion bondability and adhesiveness with a thermoplastic elastomer such as polyester, styrene, polyolefin or polyurethane.

The method for producing the modified polyacetal (co) polymer (A2) by adding and polymerizing the compound (b) having a carboxyl group and an alcoholic hydroxyl group in one molecule, the post-treatment method, etc. are the polyacetal (co). Polymer (A
It is similar to the case of 1).

Modified polyacetal (co) polymer (A2)
Is at least 1 mmol / kg or more, preferably 2
It has a carboxyl group of 200 mmol / kg. 20
When it is modified in excess of 0 mmol / kg, the excellent properties of the polyacetal (co) polymer are impaired, whereas when it is less than 1 mmol / kg, the modification effect does not appear. The quantification of the carbocycle group was determined by ¹ H-N
This can be done by MR measurement. The modified polyacetal (co) polymer (A2) has a melt index of 0.1 to 1000 g / 10 min, preferably 0.2 to
It is 500 g / 10 min.

Polyacetal resin (A) The polyacetal resin (A) comprises 99.9 to 0% by weight of the polyacetal (co) polymer (A1) and 0.1 to 100% by weight of the modified polyacetal (co) polymer (A2). And preferably a polyacetal (co) polymer (A1)
95 to 5% by weight and modified polyacetal (co) polymer (A2) 5 to 95% by weight (the total of A1 and A2 is 100% by weight). In general, the appropriate content of the modified polyacetal (co) polymer (A2) in the polyacetal resin (A) varies depending on the modification degree (carboxyl group introduction rate) of the (co) polymer (A2). The (co) polymer (A2) having a low rate of introduction of a carboxyl group can have a relatively high molecular weight, and the content of the (co) polymer (A2) is preferably high, and the rate of introduction of a carboxyl group is high. The (co) polymer (A2) generally has a relatively low molecular weight,
It is appropriate to reduce the content of (A2).

Further, in the present invention, various known additives may be added to the polyacetal resin (A) in order to improve its physical properties depending on the intended use. If you show examples of additives,
Various stabilizers, colorants, lubricants, release agents, nucleating agents, surfactants, different polymers, organic polymer improvers and inorganic, organic,
Examples of the filler include fibrous, powdery, and plate-shaped fillers such as metal, and one kind or a mixture of two or more kinds of them can be used.

II. Thermoplastic Elastomer (B) Thermoplastic Elastomer (B) Used in the Present Invention
For example, polyester-based elastomer (B
1), highly polar elastomers such as polyurethane elastomers and polyamide elastomers; polystyrene elastomers (B2); polyolefin elastomers (B3); vinyl chloride elastomers. You may use 2 or more types together. As the thermoplastic elastomer (B), a polar group such as -C (= O) O-, -NHC (= O) O- group, -NH in the constituent polymer molecule is used.
An elastomer having a C (= O)-group is suitable, and a polyester elastomer (Bl) is particularly preferable. The polyester-based elastomer (B1) may be a single type or a combination of a plurality of types with other elastomer components. Among the other elastomer components, polystyrene-based elastomer (B2) and polyolefin-based elastomer (B3) are preferable. is there.

Polyester Elastomer (Bl) Examples of the polyester elastomer (Bl) include the following polyester elastomers and the like. Polyester elastomer: A polyester / polyether type block copolymer in which the hard segment is an aromatic polyester block (d) and the soft segment is an aliphatic polyether block (e). Polyester elastomer: A polyester / polyester type block copolymer in which the hard segment is an aromatic polyester block (d) and the soft segment is an aliphatic (chain or alicyclic) polyester block (f). Among them, polyester elastomers are particularly preferable because they are excellent in flexibility and moldability. The above aromatic polyester block (d)
Is composed of a polycondensate containing an aromatic dicarboxylic acid component and a diol component as main components. As the aromatic dicarboxylic acid component, phthalic acid, terephthalic acid, isophthalic acid, 1,4- or 2,6-naphthalenedicarboxylic acid,
Examples of the aromatic dicarboxylic acid such as 4,4′-diphenyldicarboxylic acid, 4,4′-diphenylsulfonedicarboxylic acid, and 4,4′-diphenyletherdicarboxylic acid, and alkyl esters thereof may be used in combination. As the diol component, aliphatic diols such as ethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, and hexamethylene glycol; 1,4-cyclohexanediol, 1,4
A cycloaliphatic diol such as cyclohexanedimethanol;
Examples thereof include aromatic diols such as 4,4′-dihydroxybiphenyl and 2,2-bis (4′-β-hydroxyethoxyphenyl) propane, which may be used in combination. The aliphatic polyether block (e) is polyethylene glycol, polypropylene glycol, polytrimethylene ether glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol; a block or random copolymer of ethylene oxide and propylene oxide, ethylene oxide and tetrahydrofuran. Of a block or random copolymer of polyalkylene ether glycol. The non-aromatic polyester block (f) is composed of an aliphatic dicarboxylic acid, an aliphatic diol, and / or an aliphatic hydroxycarboxylic acid or a cyclic ester thereof. Examples of the aliphatic dicarboxylic acids include chain aliphatic dicarboxylic acids such as oxalic acid, succinic acid, adipic acid, azelaic acid and sebacic acid; hexahydroterephthalic acid, hexahydroisophthalic acid, dicyclohexyl-
Examples thereof include alicyclic dicarboxylic acids such as 4,4′-dicarboxylic acid, which may be used in combination. Examples of the aliphatic diol include chain aliphatic diols such as ethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol and hexamethylene glycol;
Alicyclic diols such as 1,4-cyclohexanediol and 1,4-cyclohexanedimethanol, and the like,
You may use these together. Examples of the aliphatic hydroxycarboxylic acid include ε-oxycaproic acid, and examples of the cyclic ester thereof include ε-caprolactone. These may be used in combination. The polyester elastomer (B1) is manufactured by a known method, and includes, for example, "Hytrel" (trade name of Toray Dubon Co., Ltd.); "Perprene S", "Perprene P" (trade name of Toyobo Co., Ltd.). ); "Grelax E" (trade name, manufactured by Dainippon Ink and Chemicals, Inc.); "Nuberan" (trade name, manufactured by Teijin Ltd.) and the like can be appropriately selected and used.

Polystyrene-based elastomer (B2) The polystyrene-based elastomer (B2) is a known styrene-based elastomer, that is, a hard segment is a polymer block of a styrene compound and a soft segment is a polymer block of a conjugated diene compound. Styrene-conjugated diene block copolymers or hydrogenated products thereof are mentioned. Among them, hydrogenated products are preferable from the viewpoint of compatibility with the polyester elastomer. Examples of the styrene compound include styrene, α-methylstyrene,
Examples thereof include p-methylstyrene and dimethylstyrene, with styrene being preferred. Examples of the conjugated diene compound include butadiene, isoprene, 1,3-pentadiene, and 2,3-dimethyl-1,3-butadiene. Among them, butadiene, isoprene, or a combination of both is preferable. Examples of the styrene-conjugated diene block copolymer include a styrene-butadiene-styrene block copolymer and a styrene-isoprene-styrene block copolymer. Further, specific examples of hydrogenated products of styrene-conjugated diene block copolymers include hydrogenated products of the styrene-butadiene-styrene block copolymers and hydrogenated products of styrene-isoprene-styrene block copolymers. Can be mentioned.
Furthermore, modification by copolymerization with a comonomer having a polar group copolymerizable with them, such as (meth) acrylic acid, (meth) acrylic acid alkyl ester, (meth) acrylic acid glycidyl ester, vinyl acetate, maleic anhydride, etc. Copolymers are also preferably used. The polystyrene-based elastomer (B2) is produced by a known method,
For example, from "Clayton G" (trade name of Shell Japan Co., Ltd.), "Tuftec" (trade name of Asahi Kasei Co., Ltd.), "Septon", "High Blur" (both are trade names of Kuraray Co., Ltd.), etc. Can be appropriately selected and used. The styrene elastomer (B2) in the present invention is commercially available as a compound in which the styrene elastomer is mixed with a propylene resin, a hydrocarbon rubber softening agent, an inorganic filler and the like. For example, "Clayton G compound" (trade name of Shell Japan), "Tuftec compound"
(Asahi Kasei product name), "Lavalon" (Mitsubishi Chemical product name), "Sumitomo TPE (SB series)" (Sumitomo Chemical product name) and the like.

Polyolefin-based Elastomer (B3) The polyolefin-based elastomer (B3) is produced by a known method, for example, a mixture in which the hard segment is a propylene-based resin and the soft segment is an ethylene-based rubber, Alternatively, a partially crosslinked product thereof can be used. As the propylene-based resin, for example,
Homopolymer of propylene, propylene and ethylene, butene-1, pentene-1, hexene-1, heptene-
1, other octons such as 1, octene-1 with 2 to 10 carbon atoms
Examples thereof include copolymers with olefins. Examples of the ethylene rubber include ethylene and propylene,
Butene-1, pentene-1, hexene-1, heptene-
1, copolymers of octene-1, etc. with α-olefins having about 3 to 10 carbon atoms; and, in addition to these, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-vinyl-2. -A copolymer obtained by copolymerizing non-conjugated dienes such as norbornene and dicyclopentadiene, for example, EPDM. Furthermore, modified copolymers obtained by copolymerizing these with the comonomer having a polar group capable of copolymerization as exemplified above are also preferably used. The polyolefin-based elastomer (B3) is manufactured by a known method, and is used as a compound containing a softening agent for hydrocarbon-based rubber, an inorganic filler, etc., for example,
From "Millastomer" (trade name of Mitsui Chemicals, Inc.), "Thermo Run" (trade name of Mitsubishi Chemical Co., Ltd.), "Sumitomo TPE" (trade name of Sumitomo Chemical Co., Ltd.), etc.,
It can be appropriately selected and used.

Further, various known stabilizers and additives may be added to the thermoplastic elastomer (B) in the present invention depending on the intended use. Examples of the stabilizer include an antioxidant, a heat resistance stabilizer (decomposition inhibitor), a weather resistance (light) stabilizer, and the like. The additives include, for example, various plasticizers, colorants, lubricants, release agents and the like, inorganic, organic,
Examples include fibrous, powdery, and plate-shaped fillers such as metal. Examples of the plasticizer include hydrocarbon rubber softeners. Hydrocarbon softeners for rubber are aromatic rings,
A mixture of naphthene ring and paraffin chain,
Paraffin chain carbon number occupies 50% or more of the total carbon paraffin oil, naphthene ring carbon number 30 to 50% of the total carbon naphthene oil, aromatic carbon number 30 of the total carbon. % Or more are classified as aromatic oils. Of these, paraffinic oil is preferably used from the viewpoint of weather resistance. Examples of the inorganic filler include talc, mica, glass fiber, whiskers, carbon fiber, calcium carbonate, titanium oxide, carbon black, glass balloons and the like. Among these, it is preferable to use calcium carbonate in terms of balance with flexibility.

III. Composite molded article A composite molded article of the present invention has a molded article site made of a polyacetal resin (A) and a molded article site made of a thermoplastic elastomer (B), and both molded article sites are fused. Is. As the molding method of the composite molded body, any molding method may be used as long as it is a molding method such as injection molding, extrusion molding, compression molding, etc., in which the conditions for thermal fusion are set, From the viewpoint of, the injection molding method is preferable. Specifically, a two-color molding method in which the primary molding portion is made of primary resin and the secondary molding portion is made of secondary resin alternately by injection molding; a primary molding body previously molded of the primary resin is made into a mold. Insert molding method in which the secondary side resin is injection-molded around the primary molded body to be integrated with the primary molded body; or a primary molded body previously molded with the primary side resin is inserted into the mold. However, there is an outsert molding method in which a secondary resin is injection-molded on a part or a plurality of parts of the primary molded product to integrate it with the primary molded product. Depending on the shape, structure and intended use of the molded product, the polyacetal resin (A) may be used as the primary resin and the thermoplastic elastomer (B) may be used as the secondary resin, or a combination thereof may be used. . However, in general, hard polyacetal resin (A)
It is preferable to mold the primary molded body in the following, and then to perform the secondary molding with the soft thermoplastic elastomer (B) in order to prevent the composite molded body from being deformed or deformed during the secondary molding or after the secondary molding. .

In order to firmly heat-bond both molded parts to each other in the secondary molding, depending on the resin temperature of the thermoplastic elastomer (B), the surface layer (of the bonding surface of the primary molded product made of the polyacetal resin (A) ( It is necessary that the interface part melts. Therefore, the resin temperature of the thermoplastic elastomer (B) in the secondary molding is at least equal to or higher than the melting point of the polyacetal resin (A), preferably 20 to 1 from the melting point.
The temperature is increased by 00 ° C, more preferably by 50 to 90 ° C.
As a method of raising or keeping the temperature of the resin, there are a method of raising the temperature of the injected resin itself within an allowable range, a method of using a hot runner mold, and a method of keeping the heated or heated resin after injection. . As the latter, a method of using a heat insulating material in the mold part that affects the heat retention of the interface part,
A heating medium may be passed through the mold part or a heating means such as a heater may be provided. By increasing the mold temperature to a certain degree, the heat loss during flow of the thermoplastic elastomer decreases, so the improvement of heat fusion is expected due to the synergistic effect of preheating, which will be described later, of the polyacetal resin (A), which is the primary molding. To be done. However, when the mold temperature is increased, the mold release property of the thermoplastic elastomer (particularly the sprue and runner) is deteriorated. In this case, by using a hot runner, the problem of releasability can be solved, and a molded product having a constant heat fusion property can be stably obtained. Further, it is basically possible to raise the mold temperature further, and it is expected that the heat fusion property will be further improved. In addition, in order to increase the molding cycle, it is possible to use a temperature control system for rapid heating and rapid cooling of the mold together. That is, the mold temperature is raised during injection molding of the thermoplastic elastomer, and the mold is rapidly cooled at the same time as the injection molding is completed.
Especially by promoting the solidification of sprue and runner,
The same effect as when using the hot runner can be obtained. In addition, in order to improve the heat fusion property, it is preferable to increase the amount of heat of the primary molded product made of the polyacetal resin (A) at the time of secondary molding.
In particular, in the insert molding method and the outsert molding method, it is desirable to preheat the primary molded body sufficiently before or after inserting the mold within a range in which discoloration or dimensional change does not pose a problem. At the time of injection, the surface temperature of the primary molded body made of the polyacetal resin (A) is 80 ° C. or higher, preferably 110 ° C. or higher and lower than the melting point of the polyacetal resin (A). Examples of the preheating method before inserting the mold include hot air heating, ultrasonic heating, and heating with heating wire.As the preheating method after inserting the mold, known means for heating the inside or outside surface of the mold can be used. Specifically, heating by passing a heated medium through the inside or outside of the mold, heating by electric heating, heating of the outside of the mold by high frequency waves, ultrasonic waves, heat rays, and the like can be mentioned. As the medium, water, an inorganic liquid such as an aqueous solution of calcium chloride;
Alkylated aromatic hydrocarbon, polyethylene glycol,
Organic liquids such as silicone oil, animal oil and vegetable oil; water vapor, gas such as air, and the like. These are appropriately selected depending on the type of resin, the size of the molded product, and the like.

[0031]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited thereto. Polyacetal (co) polymer (A1) (POM in Table 2 and below
As (A1)), DURACON (registered trademark) M90 manufactured by Polyplastics Co., Ltd. was used. The modified polyacetal (co) polymer (A2) was produced by the following production example.

(Production Examples 1 to 7) A continuous mixing reaction consisting of a barrel having a jacket for passing a heat (cold) medium on the outside and having a cross section in which two circles partially overlap each other, and a rotary shaft with a paddle. Using a machine, rotate the two rotating shafts with paddles at 150 rpm, respectively, and add the following components (a), (b) and (c) at the ratios shown in Table 1, and further add a molecular weight modifier. Then, bulk polymerization was carried out while continuously supplying methylal and 0.005 part by weight of boron trifluoride as a catalyst to the polymerization machine. Component (a): Trioxane (b) Component: bl: glycolic acid b-2: α-oxy-isobutyric acid b-3: glyceric acid b-4: malic acid (c) component c-1: 1,3-dioxolane c-2: ethylene oxide

[0033]

[Table 1]

The reaction product discharged from the polymerization machine was quickly passed through a crusher and added to an aqueous solution containing 0.05% by weight of triethylamine at 60 ° C. to deactivate the catalyst. Further, after separation, washing and drying, a crude polyacetal copolymer was obtained. Then, this crude polyacetal copolymer 100 is used.
To 4 parts by weight of triethylamine 5% by weight aqueous solution is added.
Parts by weight, pentaerythrityl-tetrakis [3- (3,
5-di-tert-butyl-4-hydroxyphenyl) propionate] was added in an amount of 0.3 part by weight, and 2
Melt kneading was carried out at 10 ° C. to remove the unstable portion. The obtained polyacetal copolymer was analyzed by ¹ H-NMR measurement using hexafluoroisopropanol-d ₂ as a solvent to analyze the proton peak shift in the adjacent portion of the carboxyl group, and its structure was such that the carboxyl group was introduced into the main chain. I confirmed that. The carboxyl group content was calculated from the proton peak intensity. Pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] 0.0 as a stabilizer was added to 100 parts by weight of the modified polyacetal (co) polymer obtained above.
3 parts by weight and 0.15 parts by weight of melamine were added, melt-kneaded at 210 ° C. in a twin-screw extruder, and pelletized modified polyacetal (co) polymer (POM (A2-1) to POM).
(A2-7)) was obtained.

[Examples 1 to 8] (Resin used) As the polyacetal resin (A), Table 2
As shown in, the modified polyacetal (co) polymer (A2-1) produced above, or a pellet blend of the modified polyacetal (co) polymer (A2-1) and the polyacetal (co) polymer (A1). Was used. As the thermoplastic elastomer (B), as shown in Table 2, the following were used alone or in a mixture of pellet blends thereof. A: Polyester elastomer (TPEE) (Hytrel 40
57, manufactured by Toray-Dyupon) B: Polyester elastomer (TPEE) (Hytrel 30
46, manufactured by Toray Deyupon C: Styrene-based elastomer (TPS) (Sumitomo TPE SB
7615, Sumitomo Chemical Co., Ltd.) D: Styrene-based elastomer (TPS) (Septon 2043, Kuraray Co.) E: Olefin-based elastomer (TPO) (Milastomer 907
(N, manufactured by Mitsui Chemicals, Inc.) (Molding of Composite Molded Body) First, a strip-shaped primary molding test piece having a length of 130 mm, a width of 13 mm and a thickness of 3.2 mm was molded using the polyacetal resin (A). The primary molding test piece was preheated at a preheating temperature of 120 ° C. (corresponding to “Yes” in Table 2). Then, the strip-shaped test piece is placed in a mold and secondary molding is performed using the thermoplastic elastomer (B) to obtain a length of 130 mm and a width of 13 mm.
A molded test piece having a thickness of 6.4 mm and a thickness of 6.4 mm was obtained. Molding conditions Primary molding (polyacetal resin (A)) Cylinder temperature: 200 ° C Mold temperature: 80 ° C Injection speed: 0.6m / min Holding pressure: 50MPa Injection / holding time: 20 seconds Cooling time: 20 seconds Secondary molding (Thermoplastic Elastomer (B)) Cylinder temperature: 250 ° C. Mold temperature: 60 ° C. Injection speed: 10 m / min Holding pressure: 20 MPa Injection / holding time: 15 seconds Cooling time: 40 seconds (test of composite molded body) test Method The peel strength of the test piece prepared above was evaluated by the 90 ° peel test as described below. The results are shown in Table 2. Peeling test conditions Apparatus: RTM-100 manufactured by Orientec Co., Ltd. Test speed: 100 mm / min Atmospheric temperature: 23 ° C. After the secondary molding, the test was carried out at a temperature of 23 ° C. and a humidity of 50
% Performed after leaving in the environment for 48 hours.

[Comparative Examples 1 to 9] Polyacetal resin (A)
As shown in Table 2, the same procedure as in Example was carried out except that only the polyacetal (co) polymer (A1) was used. The results are shown in Table 2.

[0037]

[Table 2]

As can be seen from Table 2, the strength of fusion between the molded body part made of the polyacetal resin (A) and the molded body part made of the thermoplastic elastomer (B) of the composite molded body was determined by the peeling test. When the modified polyacetal (co) polymer (A2) is contained, peel strength is improved,
It has been found that further improvement can be obtained by preheating and fusing. This is a modified polyacetal (co) polymer (A
It is presumed that the carboxyl group in 2) worked effectively and the compatibility between the polyacetal side interface and the thermoplastic elastomer side interface was improved.

[0039]

As is clear from the above description and examples, by combining a polyacetal resin containing a modified polyacetal component modified by introducing a carboxyl group with a thermoplastic elastomer, there has been no heat fusion which has been achieved in the past. It is possible to manufacture both composite molded articles having excellent adherence.
Further, the composite molded article is also excellent in adhesiveness and fusion bondability with other polyacetal resin molded articles and thermoplastic elastomer molded articles. By effectively providing composite molded products that have the advantages of both polyacetal resin and thermoplastic elastomer, new applications in electric and electronic equipment, automobile parts, office equipment parts, daily sundries parts, such as sealing applications, damping It can be preferably used for applications.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08L 59/00 C08L 59/00 67/00 67/00 // B29K 59:00 B29K 59:00 67:00 67:00 101: 12 101: 12 105: 20 105: 20 B29L 9:00 B29L 9:00 (72) Inventor Naoki Ueda 973 Miyajima, Fuji-shi, Shizuoka Polyplastics Co., Ltd. F-term (reference) 4F100 AK03A AK12A AK41A AK54B AK54K AL01B AL05A AL05B AL06B AL09A BA02 EC032 EH362 GB32 GB48 GB51 GB71 JB16A JK06 YY00A 4F206 AA03 AA23 AA24 AD05 AG03 AR064 JA07 JB12 JX00 BN01X00W15J01X15W15J01W01JW12JB02 JB12 JB12 JB12 JB02 JN15WJJW02 JN15JL02 JM04 JN4JW12JB01

Claims (11)

[Claims] 1. A polyacetal (co) polymer (A1) 9
9.9-0% by weight, and 1-200 mmol in the molecule
/ Kg of modified polyacetal (co) polymer having a carboxyl group (A2), a molded body portion composed of a polyacetal resin (A) consisting of 0.1 to 100% by weight (the total of A1 and A2 is 100% by weight). , A composite molded body obtained by fusion bonding with a molded body part made of the thermoplastic elastomer (B). 2. A polyacetal (co) polymer (A1)
Is homopolymerization of formaldehyde or a cyclic oligomer of formaldehyde represented by the general formula (CH ₂ O) n [where n is an integer of 3 or more] (both are collectively referred to as formaldehyde derivative (a)), or The composite molded article according to claim 1, which is a (co) polymer obtained by copolymerizing the formaldehyde derivative (a) with a comonomer (c) composed of a cyclic ether and / or a cyclic formal. 3. A modified polyacetal (co) polymer (A
2) homopolymerizing the formaldehyde derivative (a) in the presence of a compound (b) having a carboxyl group and an alcoholic hydroxyl group in one molecule, or copolymerizing the formaldehyde derivative (a) and the comonomer (c). The composite molded article according to claim 1 or 2, which is a modified (co) polymer obtained by polymerization. 4. The compound (b) is glycolic acid, lactic acid,
The composite molded article according to claim 3, which is at least one selected from the group consisting of α-oxyisobutyric acid, β-oxyisobutyric acid, oxypivalic acid, 12-oxystearic acid, malic acid, citric acid, glyceric acid, and tartaric acid. 5. The composite molded article according to any one of claims 1 to 4, wherein the thermoplastic elastomer (B) is a thermoplastic elastomer having a polar group. 6. The composite molded article according to claim 5, wherein the thermoplastic elastomer having a polar group is a polyester thermoplastic elastomer (B1). 7. The composite molded article according to claim 1, wherein the thermoplastic elastomer (B) contains 20% by weight or more of the polyester thermoplastic elastomer (B1). 8. The thermoplastic elastomer (B) comprises 100 parts by weight of a polyester thermoplastic elastomer (Bl) and 0 in total of a styrene thermoplastic elastomer (B2) and / or an olefin thermoplastic elastomer (B3).
1 to 400 parts by weight.
4. The composite molded article according to any one of 4 above. 9. The polyacetal resin (A) according to any one of claims 1 to 4 and the thermoplastic elastomer (B) according to any one of claims 1 and 5 to 8 in two colors. A method for molding a composite molded body, which comprises performing injection molding. 10. A primary molded article made of the polyacetal resin (A) according to any one of claims 1 to 4 is placed in a mold, and then any one of claims 1 and 5 to 8. Secondary injection molding of the thermoplastic elastomer (B) shown in claim 1, or a primary molded article made of the thermoplastic elastomer (B) according to any one of claims 1 and 5 to 8 in a mold. 10. The method for molding a composite molded article according to claim 9, wherein the polyacetal resin (A) according to any one of claims 1 to 4 is subjected to secondary injection molding after being installed. 11. A thermoplastic elastomer (B) is placed in a mold in a state where a primary molded article made of the polyacetal resin (A) is preheated to 80 ° C. or higher, and then the thermoplastic elastomer (B) is heated to a temperature equal to or higher than the melting point of the polyacetal resin (A). The method for molding a composite molded article according to claim 10, wherein the secondary injection molding is performed.