JP3315570B2 - Manufacturing method of polyester-based composite molded products - Google Patents

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 having excellent airtightness and adhesion and a method for producing the same, and provides a composite molded article suitable for various equipment parts in the fields of automobiles and electric and electronic fields.

[0002]

2. Description of the Related Art Polyethylene terephthalate (PE) which is a crystalline thermoplastic resin
T resin), polybutylene terephthalate (PBT resin)
Are used as engineering plastics in a wide range of applications such as automobiles, electric and electronic parts, etc. because of their excellent mechanical properties, electrical properties, and other physical and chemical properties and good workability. However, in recent years, various kinds of characteristics are required for automobiles and electric / electronic parts, and a two-part molded part combining different materials has been developed as one of the characteristics imparting methods. 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 composite molded product using a highly crystalline thermoplastic polyester for multiple molding, fusion at the interface between the resin on the primary side and the resin on the secondary side is insufficient. , Easy to peel off by external force, easy to warp, etc.
In many cases, the function as an integrally molded product is not satisfied. In order to compensate for the fusion strength at the interface between the two resins, the primary molded product must be provided with a mechanical structure that has a mechanical anchor effect, such as by providing undercuts or through holes, or by applying an adhesive to the primary molded product. As can be seen, 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 polybutylene terephthalate, polypropylene terephthalate, or polyethylene terephthalate has high crystallinity, it is molded by a double molding method, and a composite molded product having a high fusion strength at the interface between resins can be economically produced by a simple method. It was very difficult to produce efficiently. On the other hand, in the case of sensors, relays, and the like, there are cases where it is desired to provide a window so that the inside state can be understood, and the product material may be required to have transparency. For such products, multiple molding using an amorphous resin such as polycarbonate having high transparency has been attempted, but as can be seen from the low weld strength of amorphous resins such as polycarbonate, In the multiple molding where the primary molded product is solid, the fusion of the interface between the primary and secondary resins is insufficient, and it is easy to peel off due to external force. Often do not satisfy the function as an integral molded product,
In order to form an integrally molded product, it was necessary to use an adhesive or rely on secondary processing such as ultrasonic welding.

[0003]

Means for Solving the Problems The present inventors make use of the excellent mechanical properties, chemical properties, thermal properties, etc. of polyalkylene terephthalate-based resins and, if necessary, add a transparent moiety to a desired position. As a result of intensive studies to economically and efficiently obtain an integrally molded product having a shape, a primary material and a secondary material are appropriately selected and subjected to a multiple molding method, particularly to impart an anchor shape and use an adhesive. It has been found that a composite molded article having high adhesion strength between resins can be obtained extremely easily without going through the complicated steps of the present invention, and arrived at the present invention. That is, the present invention provides a method for producing polyalkylene terephthalate by molding.
A primary molded article composed of a copolymer (A) mainly comprising (alkylene group having 2 to 4 carbon atoms) and containing 1 to 40 mol% of another comonomer unit is formed.
Secondary injection molding of carbonate resin (B)
A composite with excellent airtightness and adhesiveness characterized by
This is a method for manufacturing a molded product .

[0004]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the constituent materials of the composite molded article of the present invention and the molding method thereof will be described in detail. In producing the composite molded article of the present invention by a multiple molding method, the primary molded article is a molded article comprising a copolymer (A) mainly containing polyalkylene terephthalate and containing 1 to 40 mol% of another comonomer unit. Used. Here, the copolymer (A) is specifically a polyalkylene terephthalate obtained by a polycondensation reaction of terephthalic acid or an ester-forming derivative thereof and an alkylene glycol or an ester-forming derivative thereof, for example, polyethylene terephthalate, polypropylene terephthalate, Copolymers mainly composed of polybutylene terephthalate and the like, into which 1 to 40 mol% of other comonomer units are introduced. As the third component (comonomer) constituting such a copolymer, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylethanedicarboxylic acid, cyclohexanedicarboxylic acid,
Known dicarboxylic acids such as adipic acid, sebacic acid and dodecanedioic acid, and alkyl, alkoxy or halogen-substituted products thereof are exemplified. 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, resorcinol, Dihydroxyphenyl, naphthalene diol, dihydroxydiphenyl ether, cyclohexanediol, 2,2-bis (4-hydroxyphenyl) propane,
Dihydroxy compounds having a relatively low molecular weight, such as diethoxylated bisphenol A, and alkyl, alkoxy or halogen substituted products thereof. These comonomer components may be introduced by mixing two or more kinds. Particularly preferred comonomer components include isophthalic acid and its ester-formable derivatives. In introducing these comonomer components, the resulting polyalkylene terephthalate-based resin is a material having the characteristics of an original engineering plastic and having both excellent airtightness and excellent adhesiveness. The content is 1 to 40 mol%, preferably in the range of 3 to 35 mol%. In the present invention, any of the copolymers produced by polycondensation can be used as the monomer and comonomer components using the compound as described above. Can be used. The copolymer (A) used to form the integrally molded article according to the present invention may be crystalline in terms of mechanical, electrical, chemical and other properties and moldability. Preferably, it has a melting point of 180 to 220 ° C. More specifically, a copolymer mainly containing polybutylene terephthalate and containing 1 to 40 mol% of other comonomer units, particularly isophthalic acid units, is particularly preferable.

Next, in order to obtain the composite molded article of the present invention, an amorphous thermoplastic polyester resin is used in the present invention as a resin which is secondarily injection-molded with respect to the primary molded article.
Use (B). Specific examples of the amorphous thermoplastic polyester resin (B) that can be used for the secondary injection molding include a polycarbonate resin, a polyarylate resin, and as the third component, isophthalic acid, bisphenol, diethylene glycol, 1,4-butanediol. And the like. A polyethylene terephthalate-based copolymer obtained by copolymerizing a required amount such as the above is mentioned. These resins may be modified by a known method. The fact that such a resin is amorphous can be confirmed, for example, by DSC from the fact that the melting point is not substantially observed. Of the above resins, in the present invention, polycarbonate resin that is particularly preferably used for secondary injection molding is a polycarbonate method, which is a solvent method, that is, a known acid acceptor in a solvent such as methylene chloride, in the presence of a molecular weight modifier,
It can be produced by a reaction between a dihydric phenol and a carbonate precursor such as phosgene or a transesterification reaction between a dihydric phenol and a carbonate precursor such as diphenyl carbonate. Here, bisphenols are examples of the dihydric phenol that can be suitably used,
2,2-bis (4-hydroxyphenyl) propane, bisphenol A, is preferred. Also, bisphenol A
May be partially or entirely substituted with another dihydric phenol. Examples of the dihydric phenol other than bisphenol A include hydroquinone, 4,4-dihydroxydiphenyl, bis (4-hydroxyphenyl) alkane, bis (4-hydroxyphenyl) cycloalkane,
Bis (4-hydroxyphenyl) sulfide, bis (4
-Hydroxyphenyl) ether or bis (3,5-dibromo-4-hydroxyphenyl) propane, bis (3,5-dichloro-4-hydroxyphenyl)
Examples include halogenated bisphenols such as propane. These dihydric phenols may be a homopolymer or a copolymer of two or more dihydric phenols. Further, the polycarbonate used in the present invention may be a thermoplastic random branched polycarbonate obtained by reacting a polyfunctional aromatic compound with a dihydric phenol and / or a carbonate precursor. The polycarbonate used in the present invention is particularly preferably one having high fluidity.

The resin material (A) and the resin material (B) constituting the composite molded article of the present invention are supplemented with a small amount of another thermoplastic resin in order to impart desired properties. May be. Examples of the auxiliary thermoplastic resin include polyolefin-based polymers, polyamide-based polymers, polycarbonate-based polymers, polyarylate-based polymers, polyester-based polymers other than the main component (for example, completely aromatic polyester), and styrene-based polymers. Coalescing (eg AS or ABS
Resin), polyphenylene oxide polymer, acrylate polymer, polyacetal, polysulfone, polyether sulfone, polyetherimide, polyether ketone, polyarylene sulfide polymer, fluororesin, olefin thermoplastic elastomer (eg, EPD)
M or ionomer), styrene-based thermoplastic elastomer (for example, SBS or SEBS), urethane-based thermoplastic elastomer, polyester-based thermoplastic elastomer,
Examples thereof include a polyamide-based thermoplastic elastomer, a polyether-based thermoplastic elastomer, and modified products thereof, and these thermoplastic resins may be used as a mixture of two or more kinds. The resin materials (A) and (B) constituting the molded article of the present invention 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, polyamide,
High-melting organic fibrous substances such as fluororesins and acrylic resins can also be used. On the other hand, as the particulate filler, carbon black, silica, quartz powder, glass beads, glass powder, calcium silicate, aluminum silicate, kaolin, talc, clay, diatomaceous earth, silicates such as wollastonite, Oxides of metals such as iron oxide, titanium oxide and alumina, carbonates of metals such as calcium carbonate and magnesium carbonate, sulfates of metals such as calcium sulfate and barium sulfate, other silicon carbide, silicon nitride, boron nitride, various metals And the like. 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, particularly 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 material (A) or (B). If it is more than this, the moldability and toughness are impaired, which is not preferable. Particularly preferably 30
% By weight or less.

The resin material (A) used in the present invention
And (B) are known substances other than the above, which are generally added to a thermoplastic resin in order to impart desired properties to one or both of them, that is, various kinds of substances such as antioxidants and ultraviolet absorbers. It is of course possible to incorporate stabilizers, antistatic agents, flame retardants, flame retardant aids, coloring agents such as dyes and pigments, lubricants, plasticizers and crystallization accelerators, crystal nucleating agents, mold release agents, etc. is there.

In addition, in blending the above-mentioned thermoplastic resin, filler, additive and the like with the resin material (B) of the present invention, it is necessary to maintain the excellent transparency inherent in the resin material (B). In such cases, it is necessary to consider the type and amount of these compounds. Resin material with excellent transparency
The composite molded article formed by using (B) and having a transparent portion at a desired position is the main object of the present invention, and is particularly preferable.

[0009] 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. A composite molded article having a high fusion strength can be obtained only by selecting a resin material and a secondary resin material, particularly by selectively using a polyalkylene terephthalate copolymer (A) as the primary resin material.

[0010]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples. Examples 1 to 4 and Comparative Examples 1 to 2 Using the resin materials (A) and (B) described below and the resin material for comparison, composite molded articles were prepared in combinations shown in Table 1, and the adhesion strength was evaluated. Was. Table 1 shows the results. Resin material (A) PBT copolymer 1: PBT copolymer obtained by copolymerizing 12.5 mol% of dimethyl isophthalate (melting point: 205 ° C.) GF-PBT copolymer 1: 30 wt. % PBT copolymer 2: PBT copolymer obtained by copolymerizing 5 mol% of dimethyl isophthalate (melting point: 215 ° C.) PBT copolymer 3: PBT copolymer obtained by copolymerizing 17.5 mol% of ethylene glycol ( (Melting point: 205 ° C.) Resin material (B) PC: polycarbonate resin Comparative resin material PBT: polybutylene terephthalate resin GF-PBT: PBT blended with 30% by weight of glass fiber The adhesion strength was evaluated as follows. [Adhesion Strength Evaluation Method] First, the resin shown as the primary resin material in Table 1 was used, and as a primary molded product, FIG.
A half of the ASTM No. 1 dumbbell shown in FIG. Next, this molded piece is mounted on a mold of an ASTM No. 1 dumbbell, and secondary molding is performed using the resin shown as the secondary resin material as a secondary material, and a joint is formed at the center shown in FIG. A dumbbell-shaped composite molded product having the following formula was obtained. The adhesion strength (tensile strength, tensile elongation) of the composite molded article was measured using a tensile tester.

[0011]

[Table 1]

[0012]

According to the present invention, by selectively using the specific resin materials (A) and (B) as described above, it is possible to provide an anchor shape under ordinary molding temperature conditions or to use an adhesive. Without using it, it is possible to easily and economically efficiently produce a composite molded article having a strong interfacial adhesion strength and airtightness that cannot be obtained by the conventional double molding method and having a transparent portion. Moreover, the composite molded article of the present invention has excellent thermal stability of polyester-based engineering plastic,
It has physical properties, mechanical properties, etc., and is excellent in transparency and impact resistance, and is suitable for many applications in the automotive field and the electric / electronic field where such properties are required as molded products.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a molded product for measuring adhesion strength used in Examples, (a) is a primary molded product, and (b) is a dumbbell having a joint at the center where a secondary molded product is joined. It is a composite molded article.

[Explanation of symbols]

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

Claims (4)

(57) [Claims] 1. A molding method comprising a polyalkylene terephthalate (alkylene group having 2 to 4 carbon atoms) mainly comprising
Copolymer containing mol% of other comonomer units
Form a primary molded product consisting of (A) , and update this primary molded product.
And then injection molding the polycarbonate resin (B)
Excellent air-tightness and adhesiveness characterized by integrating
Manufacturing method of composite molded products. 2. The composite molded article according to claim 1, wherein the copolymer (A) is a copolymer mainly composed of polybutylene terephthalate and containing 1 to 40 mol% of another comonomer unit.
Manufacturing method. 3. The method for producing a composite molded article according to claim 1, wherein the copolymer (A) is a copolymer containing an isophthalic acid unit as a comonomer unit . 4. The method for producing a composite molded article according to claim 1, wherein the copolymer (A) has a melting point of 180 to 220 ° C.