JPH11320606A - Polyacetal composite molded product and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To readily obtain high interfacial bonding strength, good slidability, chemical resistance, fatigue resistance or the like by integrally molding a resin material mainly consisting of polyacetal resin and a resin material mainly consisting of polyalkylene terephtalate by a double molding or a two-color molding method. SOLUTION: A molded product consisting of a polyacetal resin material A and a resin material B mainly consisting of a polyalkylene terephtalate are molded by a double molding or a two-color molding method. The acetal resin is, preferably, a type of copolymer, wherein the copolymer component is ethylene oxide, propylene oxide, 1,3-dioxolane or the like, and the comonomer unit weight is preferably 8 mol.% or less. The polyalkylene terephtalate resin material B is polyethylene terephtalate, polyprophylene terephtalate, polybutylene terephtalate, or a copolymer mainly consisting thereof introduced with other comonomer unit of 40 mol.% or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite molded article excellent in chemical resistance, slidability and printability, paintability and weather (light) resistance and a method for producing the same, and relates to various equipment in the fields of automobiles and electric / electronics. It is intended to provide a composite molded article suitable for a part.

[0002]

2. Description of the Related Art Polyacetal resins have excellent mechanical strength, chemical resistance, slidability, etc. and are relatively inexpensive. It is used for a wide range of applications such as. However, in recent years, automobiles, electric and electronic parts are required to have various characteristics,
As one of the characteristics imparting methods, a composite molded part combining different materials has been developed. Generally, as a method of integrally molding two kinds of materials, partially different characteristics are obtained by a dual molding method in which a dissimilar resin is secondarily molded on a primary molded article of the resin and the interface is fused and fixed. Although it is known to obtain a composite molded product having a polyacetal resin having high crystallinity as a primary molded product, fusion at the interface between the primary resin and the secondary resin is not known. Sufficiently, it is easily peeled off by external force, and often does not satisfy the function as an integrally molded product in use. In order to supplement the fusion strength at the interface between the two resins, the primary molded product is provided with a mechanical structure that has a mechanical anchoring effect, such as providing undercuts and through holes, and a method of applying an adhesive to the primary molded product. However, the shape becomes complicated and the process becomes complicated, which is economically disadvantageous, and is also undesirable in terms of production efficiency. In particular, since polyacetal resin has high crystallinity, it is extremely difficult to obtain high bonding strength only at the interface fusion strength without providing a mechanical structure with a mechanical anchor effect for composite molded products in bonding between dissimilar materials. Met.

[0003]

Means for Solving the Problems The present inventor has economically developed a composite molded product utilizing the good sliding property, chemical resistance, fatigue resistance and low cost of the resin material (A) mainly composed of polyacetal resin. As a result of intensive studies to obtain efficient and efficient, if the resin material (B) mainly composed of polyalkylene terephthalate is used as the secondary molding material, mechanical anchors such as providing undercuts and through holes in the primary molded product It is possible to obtain a composite molded product with a high fusion strength at the joint without providing a shape structure having an effect or applying an adhesive to the primary molded product, and to obtain a resin material (B). The present inventors have found that a composite molded product utilizing good appearance, secondary workability, flame retardancy, and heat resistance can be obtained, and have reached the present invention.
That is, the present invention provides a composite molding in which a resin material (A) mainly composed of a polyacetal resin and a resin material (B) mainly composed of polyalkylene terephthalate are integrally molded by a double molding or two-color molding method. Article and its manufacturing method.

[0004]

BEST MODE FOR CARRYING OUT THE INVENTION The constituent materials of the composite molded article of the present invention and the method for producing the same will be described in detail below. In producing the composite molded article of the present invention by a multiple molding method, a molded article made of a polyacetal resin material (A) is used as a primary molded article. Such a primary molded article can be obtained by molding by a known molding means. Either a homopolymer or a copolymer can be used as the acetal resin, but a copolymer type is more preferably used. In the case of a copolymer, the comonomer component includes ethylene oxide, propylene oxide, 1,3-dioxolane and the like, and the comonomer unit amount is preferably 8 mol% or less. If it exceeds 8 mol%, the characteristics as an acetal resin will be weakened, which is not preferable. Further, those obtained by blending a polyurethane or an acrylic elastomer with an acetal resin are also preferably used.

Next, in order to obtain a composite molded article of the present invention, a polyalkylene terephthalate-based resin material (B) is used in the present invention as a resin which is injection-molded secondary to the above-mentioned primary molded article. Specifically, it is a polyalkylene terephthalate obtained by a polycondensation reaction of terephthalic acid or an ester-forming derivative thereof with an alkylene glycol or an ester-forming derivative thereof and / or a copolymer mainly containing the same, such as polyethylene terephthalate and polypropylene terephthalate. , Polybutylene terephthalate, or a copolymer containing the same as a main component, into which another comonomer unit of 40 mol% or less is introduced. The third component (comonomer) constituting such a copolymer includes isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylethanedicarboxylic acid, cyclohexanedicarboxylic acid, adipic acid, sebacic acid, and dodecanediacid. Examples of such known dicarboxylic acids and their alkyl, alkoxy or halogen-substituted products. These dicarboxylic acid compounds can also be used as a comonomer component in the form of a derivative capable of forming an ester, for example, a lower alcohol ester such as dimethyl ester, for polycondensation. Examples of the dihydroxy compound used as the third component for constituting the copolymer include ethylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, hydroquinone,
Relatively low molecular weight dihydroxy compounds such as resorcinol, dihydroxyphenyl, naphthalene diol, dihydroxydiphenyl ether, cyclohexanediol, 2,2-bis (4-hydroxyphenyl) propane, diethoxylated bisphenol A, and alkyl, alkoxy or halogen substitution thereof Body. These comonomer components may be introduced by mixing two or more kinds. In introducing these comonomer components,
Since the resulting polyalkylene terephthalate-based resin is a material having characteristics as an original engineering plastic and having excellent characteristics of airtightness and adhesion, the content of the copolymer component is in the range of 1 to 40 mol%. Is more preferable, and more preferably in the range of 3 to 35 mol%.

In the present invention, any of the polyalkylene terephthalate resins formed by polycondensation using the above-mentioned compounds as monomer and comonomer components can be used, and these can be used alone or as a mixture of two or more. It can be used as material (B). The polyalkylene terephthalate-based resin material (B) to be injection-molded secondarily to constitute the integrally molded article in the present invention is crystalline in terms of mechanical, electrical, and chemical properties. preferable. More specifically, a polybutylene terephthalate resin and a copolymer mainly containing polybutylene terephthalate and containing 1 to 40 mol% of other comonomer units, particularly isophthalic acid units, are particularly preferable.

Further, the resin material constituting the molded article of the present invention
(B) may be supplemented with a small amount of another thermoplastic resin in order to impart desired properties. Examples of such auxiliary thermoplastic resins include, for example, polyolefin-based polymers, polyamide-based polymers, polycarbonate-based polymers,
Polyarylate polymer, polyester polymer other than the main component (eg, completely aromatic polyester), styrene polymer (eg, AS or ABS resin), polyphenylene oxide polymer, acrylate polymer, polyacetal, polysulfone, poly Ether sulfone, polyether imide, polyether ketone, polyarylene sulfide-based polymer, fluororesin, olefin-based thermoplastic elastomer (for example, EPDM or ionomer),
Styrenic thermoplastic elastomer (for example, SBS or S
EBS), a urethane-based thermoplastic elastomer, a polyester-based thermoplastic elastomer, a polyamide-based thermoplastic elastomer, a polyether-based thermoplastic elastomer, or a modified product thereof, and the like. It can also be used. On the other hand, when these thermoplastic resins are blended with the resin material (A), it is possible to blend an appropriate amount within a range that does not significantly impair the properties according to the purpose.

Further, a resin material constituting the molded article of the present invention
(A) and (B) may contain an inorganic filler. Such a filler is preferably blended in order to obtain excellent properties such as mechanical strength, heat resistance, dimensional stability, and electrical properties, and is particularly effective for increasing rigidity. For this purpose, a fibrous, powdery or plate-like filler is used depending on the purpose. Examples of the fibrous filler include glass fiber, asbestos fiber, carbon fiber, silica fiber, silica / alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber, stainless steel, aluminum, titanium, Inorganic fibrous substances such as fibrous materials of metals such as copper and brass can be used. Particularly typical fibrous fillers are glass fibers. In addition, a high melting point organic fibrous substance such as polyamide, fluororesin, and acrylic resin can also be used. On the other hand, the powdery and granular fillers include carbon black, graphite, silica, quartz powder, glass beads, glass balloon, glass powder, calcium silicate, aluminum silicate, kaolin, talc, clay, silicate earth, and wollastonite. Metal oxides such as silicates, iron oxides, titanium oxides and aluminas, metal carbonates such as calcium carbonate and magnesium carbonate, calcium sulfate, lead sulfates of metals such as barium sulfate, other silicon carbide, silicon nitride, Examples include boron nitride and various metal powders. Examples of the plate-like filler include mica, glass flake, various metal foils, and the like. These inorganic fillers can be used alone or in combination of two or more. The combined use of a fibrous filler, especially a glass fiber or a carbon fiber, and a granular or plate-like filler is a preferable combination, particularly in terms of having both mechanical strength, dimensional accuracy, electrical properties and the like. The amount of the inorganic filler added is 40% by weight or less based on the total amount of the resin materials (A) and (B). If it is more than this, the moldability and toughness are impaired, which is not preferable. Particularly preferably, it is at most 30% by weight.

The resin material (A) used in the present invention
And (B) is a known substance other than the above, which is generally added to a thermoplastic resin within a range that does not affect the fusing property of both or one or both of them to impart desired properties according to the purpose. That is, various stabilizers such as antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, flame retardants, flame retardant assistants, coloring agents such as dyes and pigments, lubricants, plasticizers and crystallization accelerators Of course, it is also possible to mix a crystal nucleating agent, a release agent, a surfactant, an antistatic agent and the like in any combination.

[0010] The composite molded article of the present invention comprises the above (A) and (B) 2
It is molded by a so-called multiple molding method using various kinds of resin materials. As a molding method, injection molding, compression molding and other molding methods are applied, but injection molding is generally preferred.
In the present invention, the resin material (A) is preliminarily molded into a primary molded product, and then the resin material (B) is secondarily injection molded, fused and integrated, and the primary side is formed. Depending on the combination of the resin material and the secondary resin material and the molding conditions, a composite molded article having a high fusion strength can be obtained. In order to obtain a sufficient fusion strength, when molding such a secondary resin material, the molding temperature should be set at 100 degrees below the melting point of the resin material (A).
It is desirable that the temperature be higher than or equal to ° C., and that the time from the start of injection to the completion of filling be within 1.0 second, and more preferably within 0.8 second.

[0011] Further, the joining surface between the primary molded article and the secondary molding material of the composite molded article of the present invention is formed at the flow end of the secondary molding material, so that a composite molded article having extremely high fusion strength can be obtained. it can. By providing irregularities such as grain on the primary molded product, a composite molded product with even higher fusion strength can be obtained.

[0012]

〔Molding condition〕

Molding machine: FUNAC50B Mold: 1/8, 1/4 inch combustion test piece mold (1/8 inch combustion test piece mold) The molding temperature refers to the temperature at the plasticizing cylinder of the molding machine. The filling time was the time from the start of injection to the switching of pressure holding. Primary molding conditions for resin material (A)

[0013]

[Table 1]

Secondary molding conditions for resin material (B)

[0015]

[Table 2]

Resin material (A) POM: polyacetal resin (melting point 165 ° C.) Resin material (B) PBT: polybutylene terephthalate (melting point 223 ° C.) PBT copolymer: PBT copolymer obtained by copolymerizing 12.5 mol% of dimethyl isophthalate Combined (melting point 205 ° C) PAE: Polyamide thermoplastic elastomer Adhesive strength was evaluated as follows. [Adhesion Strength Evaluation Method] First, a 1 / 8-inch thick combustion test piece was molded as a primary molded product using the resin shown as the primary resin material in Table 1. Next, this molded piece was cut in half from the center and mounted again on a 1 / 8-inch thick combustion test piece mold so that the flow end surface was the joining surface, and then subjected to secondary molding. Thickness with a joint at the center shown in 1
A composite molded article in the shape of a / 8 inch combustion test piece was obtained.
The adhesion strength (tensile strength, tensile elongation) of the composite molded product is
It measured using the tensile tester. Further, when the fracture surface on the primary molded product side after the tensile strength measurement was observed in Example 3, a state in which a part of the resin material was torn was observed, and it was confirmed that the resin material was clearly fused.

[0017]

[Table 3]

Examples 4 to 7 Table 4 shows the results of molding in Example 3 by changing the filling time.

[0019]

[Table 4]

[0020]

According to the present invention, by using the specific resin materials (A) and (B) as described above, it is possible to provide an anchor shape under specific molding conditions or to use an adhesive. In addition, a composite molded product having a strong interfacial adhesion strength that cannot be obtained by the conventional double molding method can be easily, economically and efficiently produced. Moreover, the composite molded article of the present invention
Polyacetal resin has good slidability, chemical resistance, fatigue resistance, and low cost, and polyester engineering plastic has good appearance, secondary workability, flame retardancy, and heat resistance. It is suitable for many applications in the automotive field and electric / electronic field where characteristics are required.

[Brief description of the drawings]

FIG. 1 is a view showing a molded product for measuring adhesion strength used in Examples, and a 1/8 inch thick combustion test having a joint at the center where a primary molded product and a secondary molded product are joined. It is a one-sided composite molded product.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Primary molded article 2 Secondary molded article 3 Joint 4 Gate

Claims (14)

[Claims] 1. A composite molded article obtained by integrally molding a resin material (A) mainly composed of a polyacetal resin and a resin material (B) mainly composed of polyalkylene terephthalate by a double molding or a two-color molding method. . 2. The composite molded article according to claim 1, wherein the resin material (A) is a polyacetal resin mainly composed of oxymethylene and containing not more than 8 mol% of another comonomer unit. 3. The composite molded article according to claim 1, wherein the resin material (B) comprises a resin having crystallinity. 4. The composite molded article according to claim 1, wherein the resin material (B) comprises a copolymer mainly composed of polyalkylene terephthalate and containing another comonomer unit of 40 mol% or less. . 5. The resin material according to claim 1, wherein the resin material (B) is a copolymer mainly composed of polybutylene terephthalate and containing another comonomer unit of 40 mol% or less.
Item. 6. The composite molded article according to claim 1, wherein the resin material (B) comprises a polybutylene terephthalate resin. 7. The composite molded article according to claim 1, wherein the resin material (B) comprises a polyethylene terephthalate resin. 8. A primary molded article comprising a resin material (A) mainly composed of a polyacetal resin, and a resin material (B) mainly composed of polyalkylene terephthalate is secondarily injection-molded, and the two are fused and integrated. A method for producing a composite molded article. 9. The method according to claim 8, wherein the resin material (B) is injection-molded at a temperature 100 ° C. or more higher than the melting point of the resin material (A). 10. The method according to claim 9, wherein the time from the start of injection of the secondary resin material to the completion of filling is within 1.0 second. 11. The production of a composite molded article according to claim 8, wherein the resin material (A) is a polyacetal resin mainly containing oxymethylene and containing not more than 8 mol% of another comonomer unit. Method. 12. The composite molded article according to claim 8, wherein the resin material (B) is a copolymer mainly composed of polybutylene terephthalate and containing another comonomer unit of 40 mol% or less. Manufacturing method. 13. The method for producing a composite molded product according to claim 8, wherein the resin material (B) is made of a polybutylene terephthalate resin. 14. A composite molded article obtained by the production method according to claim 8.