JPH09141686A - Composite molded product of polyester and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain very easily a composite molded product with high interresin adhesive strength by molding a primary molding of noncrystalline thermoplastic polyester resin and polyalkylene terephthalate resin into a monolithic form using a multiple molding method. SOLUTION: When manufacturing a composite molding by a multiple molding method, a molding of noncrystalline thermoplastic polyester resin is used as a primary molding. The concrete examples of the noncrystalline thermoplastic polyester resin used for the manufacture of the primary molding are polycarbonate resin and polyallylate resin. The resin to be secondarily injection-molded to the primary molding is polyalkylene terephthalate resin. The composite molding is manufactured by the so-called multiple molding method using two different types of resin material.

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. For the purpose of supplementing the fusion strength at the interface between both resins, it is necessary to provide a shape structure that has a mechanical anchoring effect such as providing an undercut or a through hole in the primary molded product, or applying an adhesive to the primary molded product. As can be seen, it is economically disadvantageous because the shape is complicated and the process is complicated, and it is not desirable 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 a sensor, a relay, etc., there is a case where it is desired to provide a window so that the internal state can be seen, and thus the product material may be required to be transparent. For such products, multiple molding using amorphous resin such as polycarbonate with good transparency has been attempted, but amorphous resin such as polycarbonate has a low weld strength. Adhesion of the joint surface is likely to be insufficient, much less fusion of the interface between the resin on the primary side and the resin on the secondary side in multiple molding where the primary side molded product is solid, easy to peel off due to external force, Often does not satisfy the function as an upper integrally 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. Further, in the double molding, from the viewpoint of the fusion property of the resin on the resin bonding surface, it is common to use a resin having a low melting point (processing temperature) on the primary side and a resin having a high melting point (processing temperature) on the secondary side. It has been considered that, in general, sufficient adhesion strength cannot be obtained with the reverse combination, and sufficient adhesion strength cannot be obtained with such combination.

[0003]

DISCLOSURE OF THE INVENTION The inventors of the present invention have made use of the excellent mechanical properties, chemical properties, thermal properties, etc. of polyalkylene terephthalate resins and, if necessary, have a transparent site at a desired position. As a result of earnestly studying to obtain an integrally molded product having an economical efficiency, the multiple molding method was used, and surprisingly, by selecting the primary side material and the secondary side material different from the conventional common sense, especially the anchor shape The present inventors have found that a composite molded article having a high adhesion strength between resins can be obtained extremely easily without going through complicated steps such as applying and using an adhesive. That is, the present invention has excellent airtightness and adhesiveness obtained by integrally molding a primary molded product made of an amorphous thermoplastic polyester resin (A) and a polyalkylene terephthalate resin (B) by a multiple molding method. And a method for manufacturing the same.

[0004]

BEST MODE FOR CARRYING OUT THE INVENTION The constituent materials of the composite molded article of the present invention and the molding method thereof will be described in detail below. In producing the composite molded article of the present invention by the multiple molding method, a molded article made of the amorphous thermoplastic polyester resin (A) is used as the primary molded article. Such a primary molded product can be easily obtained by generally molding an amorphous thermoplastic polyester resin by a known molding means. In addition, by using a thermoplastic polyester resin that is crystalline in nature and utilizing its crystallization characteristics, glass transition temperature, and other characteristics to control molding conditions, etc., a substantially amorphous molded product can be obtained. It is also possible to obtain it, which can also be used as the primary molded product in the present invention. Specific examples of the amorphous thermoplastic polyester resin that can be used to form the primary molded article include polycarbonate resin, polyarylate resin, and as the third component, isophthalic acid, bisphenol, diethylene glycol, 1,4-butanediol, etc. Examples thereof include a polyethylene terephthalate-based copolymer in which a necessary amount is copolymerized. These resins may be modified by a known method. Whether the resin or the molded article is amorphous can be confirmed by, for example, DSC, since its melting point is not substantially observed. On the other hand, as a specific example of the latter, a polyethylene terephthalate resin or a modified product thereof can be given as a representative example. Since the polyethylene terephthalate resin has a low crystallization rate and a high glass transition temperature, a substantially amorphous molded product can be relatively easily obtained by molding with a low temperature mold. In this case, whether or not the molded product is amorphous can be confirmed by the substantial presence or absence of a recrystallization peak. Any of the above-mentioned molded articles can be used as the primary molded article of the present invention, but it is preferably a polycarbonate resin, a polyethylene terephthalate resin, a polyethylene terephthalate-based copolymer, and particularly preferably the primary molded article. It is made of polycarbonate resin.

In the present invention, the polycarbonate particularly preferably used for forming the primary molded article is a solvent method, that is, in the presence of a known acid acceptor and a molecular weight modifier in a solvent such as methylene chloride, in the presence of a dihydric phenol and phosgene. It can be produced by a reaction with such a carbonate precursor or a transesterification reaction between a dihydric phenol and a carbonate precursor such as diphenyl carbonate. Here, bisphenols are preferably used as the dihydric phenol, and 2,2-bis (4-hydroxyphenyl) propane, that is, bisphenol A is particularly preferable. Further, bisphenol A may be obtained by partially or entirely substituting another dihydric phenol. Examples of the dihydric phenol other than bisphenol A include hydroquinone and 4,4-
Compounds such as dihydroxydiphenyl, bis (4-hydroxyphenyl) alkane, bis (4-hydroxyphenyl) cycloalkane, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) ether or bis (3,5- Mention may be made of halogenated bisphenols such as dibromo-4-hydroxyphenyl) propane, bis (3,5-dichloro-4-hydroxyphenyl) propane. These dihydric phenols may be homopolymers or copolymers 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 highly fluid.

The polyethylene terephthalate resin and the polyethylene terephthalate copolymer preferably used for forming the primary molded article in the present invention are terephthalic acid or its ester forming derivative and C2 alkylene glycol or its ester forming derivative. And a copolymer obtained by copolymerizing the polymer obtained by polycondensation reaction with a third component. The monomers to be copolymerized include, as dibasic acid components other than terephthalic acid or its lower alcohol ester, isophthalic acid, naphthalenedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid,
Aliphatic and aromatic polybasic acids such as succinic acid, or ester-forming derivatives thereof, aromatic hydroxycarboxylic acids such as hydroxybenzoic acid and hydroxynaphthoic acid, or ester-forming derivatives thereof, and glycols other than ethylene glycol. As a component, a usual alkylene glycol such as diethylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol,
Neopentyl glycol, cyclohexanedimethanol, etc., lower alkylene glycol such as 1,3-octanediol, aromatic glycol such as bisphenol, ethylene oxide 2 mol adduct of bisphenol A, propylene oxide 3 mol adduct of bisphenol A, etc. Examples thereof include oxide adduct alcohols, polyhydroxy compounds such as glycerin and pentaerythritol, and ester-forming derivatives thereof. Depending on the type and copolymerization ratio of these copolymerization components, the polymer to be produced may be crystalline or substantially amorphous. However, as described above, the molding conditions and the like are controlled as necessary. As a result, a substantially amorphous molded product can be used as the primary molded product in the present invention. The polyethylene terephthalate resin used in the primary molded article in the present invention includes
Unmodified polyethylene terephthalate or isophthalic acid-modified polyethylene terephthalate copolymer is preferable, and the effect of the present invention is remarkable.

The primary molded article obtained as described above is generally transparent, and a composite molded article using such a primary molded article is the main object of the present invention, and is particularly preferable. However, the present invention is not limited to this, and may be opaque or low in transparency in relation to other components and the like mixed with the material for forming a primary molded product.

Next, in order to obtain the composite molded article of the present invention, a polyalkylene terephthalate resin (B) is used in the present invention as a resin that is injection-molded secondary to the above-mentioned primary molded article. Specifically, it is a polyalkylene terephthalate obtained by polycondensation reaction of terephthalic acid or its ester-forming derivative with alkylene glycol or its ester-forming derivative, and / or a copolymer containing this as a main component, such as polyethylene terephthalate and polypropylene terephthalate. , Polybutylene terephthalate,
Alternatively, a copolymer mainly composed of this and having 40 mol% or less of another comonomer unit introduced therein can be mentioned. As the third component (comonomer) that constitutes such a copolymer,
Known dicarboxylic acids such as isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylethanedicarboxylic acid, cyclohexanedicarboxylic acid, adipic acid, sebacic acid and dodecanedioic acid, and alkyl, alkoxy or halogen substitution products thereof. Is mentioned. Further, these dicarboxylic acid compounds can also be used as a comonomer component by being used for polycondensation in the form of a derivative capable of forming an ester, for example, a lower alcohol ester such as dimethyl ester. Further, examples of the dihydroxy compound used as the third component for forming the copolymer include ethylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, hydroquinone, resorcinol, Relatively low molecular weight dihydroxy compounds such as dihydroxyphenyl, naphthalene diol, dihydroxy diphenyl ether, cyclohexane diol, 2,2-bis (4-hydroxyphenyl) propane and diethoxylated bisphenol A, and their alkyl, alkoxy or halogen substitution products. Is. Two or more kinds of these comonomer components may be mixed and introduced. When introducing these comonomer components,
The polyalkylene terephthalate resin that is produced is a material that has the properties of an original engineering plastic and has excellent airtightness and adhesion, so the content of the copolymerization component is in the range of 1-40 mol%. Is preferable, and more preferably in the range of 3-35 mol%. In the present invention, any of the polyalkylene terephthalate-based resins produced by polycondensation can be used as the monomer and comonomer components of the compounds as described above, and these can be used alone or in combination of two or more thereof to obtain the resin material (B ) Can be used as The polyalkylene terephthalate-based resin (B) to be secondarily injection-molded to form the integrally molded product in the present invention is preferably crystalline in terms of various properties such as mechanical, electrical and chemical properties. . Further, more specifically, a copolymer mainly composed of a polybutylene terephthalate resin and a polybutylene terephthalate and containing 1 to 40 mol% of other comonomer units, and particularly an isophthalic acid unit is particularly preferable.

Further, a resin material constituting the molded article of the present invention
A small amount of other thermoplastic resin may be supplementarily added to (B) in order to impart desired properties. Examples of such an auxiliary thermoplastic resin include a polyolefin-based polymer, a polyamide-based polymer, a polycarbonate-based polymer,
Polyarylate-based polymer, polyester-based polymer other than the main component (for example, completely aromatic polyester), styrene-based polymer (for example, AS or ABS resin), polyphenylene oxide-based polymer, acrylate-based 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 (eg SBS or S
EBS), urethane-based thermoplastic elastomer, polyester-based thermoplastic elastomer, polyamide-based thermoplastic elastomer, polyether-based thermoplastic elastomer, or modified products thereof, and the like, and two or more kinds of these thermoplastic resins are mixed. It can also be used. On the other hand, it is not common to blend these thermoplastic resins into the resin material (A) from the viewpoint of transparency, etc., but it is acceptable to blend an appropriate amount within the range that does not significantly impair the properties depending on the purpose. .

Further, the resin material constituting the molded article of the present invention
Inorganic fillers can be added to (A) and (B). Such fillers are preferably blended in order to obtain excellent properties such as mechanical strength, heat resistance, dimensional stability, and electrical properties, and are particularly effective for increasing rigidity. For this purpose, a fibrous, powdery or plate-like filler is used depending on the purpose. As the fibrous filler, glass fiber, asbestos fiber, carbon fiber, silica fiber, silica-alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber, further stainless steel, aluminum, titanium, Inorganic fibrous substances such as metallic fibrous substances 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, as the particulate filler, carbon black, silica, quartz powder, glass beads, glass powder, calcium silicate, aluminum silicate, kaolin,
Silicates such as talc, clay, diatomaceous earth, wollastonite, oxides of metals such as iron oxide, titanium oxide and alumina, carbonates of metals such as calcium carbonate and magnesium carbonate, calcium sulfate, barium sulfate, etc. Examples thereof include metal sulfates, silicon carbide, silicon nitride, boron nitride, and various metal powders. Further, as the plate-like filler, mica,
Examples thereof include glass flakes and various metal foils. These inorganic fillers can be used alone or in combination of two or more.
Fibrous fillers, especially glass fibers or carbon fibers, in combination with granular or plate-like fillers are particularly mechanical strength and dimensional accuracy,
This is a preferable combination in terms of having electrical properties and the like. The addition amount of the inorganic filler is 40% by weight or less based on the total amount of the resin materials (A) and (B). If it is more than this range, the formability and toughness are impaired, which is not preferable. It is particularly preferably 30% by weight or less. However, in the case of the resin material (A), it is necessary to consider the type and addition amount of the inorganic filler in consideration of maintaining the transparency which is the original purpose.

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.

The composite molded article of the present invention comprises the above (A), (B) 2
It is molded by a so-called multiple molding method using various kinds of resin materials. As the 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 preformed into a primary molded product, and then the resin material (B) is secondarily injection-molded and fusion-bonded to be integrated. A composite molded article having high fusion strength can be obtained only by selecting the resin material and the secondary resin material.

[0013]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples. Examples 1 to 5 and Comparative Examples 1 to 4 Using the resin materials (A) and (B) described below, composite molded articles were prepared with the combinations shown in Table 1, and the adhesion strength was evaluated. The results are shown in Table 1. Resin material (A) PC: Polycarbonate resin PET: Polyethylene terephthalate resin Resin material (B) PBT: Polybutylene terephthalate resin GF-PBT: PBT mixed with 30% by weight of glass fiber PBT copolymer: Dimethyl isophthalate 12.5 mol % PBT copolymer (melting point 205 ° C.) GF-PBT copolymer: 30% by weight of glass fiber added to the above PBT copolymer 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 a primary molded product was prepared as shown in FIG.
Half of the ASTM No. 1 dumbbell shown in FIG. Next, this molded piece was mounted on a die of ASTM No. 1 dumbbell, and secondary molding was performed by using the resin shown as the secondary side resin material as the secondary material, and the joint portion was formed at the central portion shown in FIG. A dumbbell-shaped composite molded article having The adhesion strength (tensile strength, tensile elongation) of the composite molded product was measured using a tensile tester.

[0014]

[Table 1]

[0015]

EFFECTS OF THE INVENTION According to the present invention, by selectively using the specific resin materials (A) and (B) as described above, an anchor shape is provided under an ordinary molding temperature condition, and an adhesive is used. Without using it, 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 can be simply and economically and efficiently produced. Moreover, the composite molded article of the present invention has excellent thermal stability of polyester-based engineering plastics,
It has physical properties, mechanical properties, etc., and has excellent transparency and impact resistance, and is suitable for many applications in the automobile field and electric / electronic fields where such properties are required as a molded product.

[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 bonded portion at the center where a secondary molded product is bonded. Shaped composite molded article.

[Explanation of symbols]

 1 Primary molded product 2 Secondary molded product 3 Junction 4 Gate

Claims (8)

[Claims] 1. An air-tightness and adhesiveness obtained by integrally molding a primary molded product composed of an amorphous thermoplastic polyester resin (A) and a polyalkylene terephthalate resin (B) by a multiple molding method. Composite molded product. 2. Amorphous thermoplastic polyester resin (A)
Is a polycarbonate resin, The composite molded article according to claim 1. 3. A polyalkylene terephthalate resin
The composite molded article according to claim 1 or 2, wherein (B) is a resin having crystallinity. 4. A polyalkylene terephthalate resin
The composite molded article according to any one of claims 1 to 3, wherein (B) is a copolymer mainly composed of polyalkylene terephthalate and containing 40 mol% or less of another comonomer unit. 5. A polyalkylene terephthalate resin
The composite molded article according to any one of claims 1 to 3, wherein (B) is a copolymer mainly composed of polybutylene terephthalate and containing 40 mol% or less of another comonomer unit. 6. A polyalkylene terephthalate resin
The composite molded article according to any one of claims 1 to 3, wherein (B) is a polybutylene terephthalate resin. 7. A primary molded product made of an amorphous thermoplastic polyester resin (A) is formed by molding, and a polyalkylene terephthalate resin (B) is secondarily injection molded to this primary molded product. A method for producing a composite molded article excellent in airtightness and adhesion, characterized by integrating both. 8. A polyalkylene terephthalate resin
(B) Molding temperature is amorphous thermoplastic polyester resin
The method for producing a composite molded article according to claim 7, which is lower than the molding temperature of (A).