JP3320608B2 - Polybutylene terephthalate resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polybutylene terephthalate resin composition containing an epoxy group-modified polypropylene resin, and provides a molding material which is lightweight and has excellent mechanical properties, particularly excellent weld properties.

[0002]

2. Description of the Related Art Thermoplastic polyester resins represented by polybutylene terephthalate have excellent workability, mechanical properties, and other excellent physical and chemical properties.
It is widely used in the fields of automotive parts, electric and electronic equipment parts, and other precision equipment parts. However, polybutylene terephthalate resin has a large specific gravity of 1.3, and in recent years, particularly in the field of automobile parts and the like, low specific gravity and high strength materials are often required. Therefore, blending of a polymer having a low specific gravity has been actively performed as one means for meeting these requirements. It is known that one of the most effective means for blending a polyolefin such as polyethylene and polypropylene for the purpose is that these resins are non-polar, so they have low compatibility with polar resins, and polybutylene terephthalate resin is used. In addition to this, there is a problem that not only is the dispersion inferior, the peeling is likely to occur on the surface of the molded product, but also the strength is reduced, so that a resin composition that can withstand practical use cannot be obtained. Therefore, as a means for solving such a problem, there is a method of improving compatibility with a polybutylene terephthalate resin by using an olefin polymer modified with an epoxy group. However, even with this composition, the location where the flow of the resin flowing from the gate at the time of injection molding intersects in the mold, that is, the so-called weld portion, has low strength and elongation, and is not always sufficient as a functional resin.

[0003]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a polybutylene terephthalate resin composition which improves the strength and elongation of a weld portion and has excellent mechanical properties and weld characteristics.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to solve this problem, and as a result, added an epoxy-modified polypropylene resin to a thermoplastic polyester resin, especially a polybutylene terephthalate resin.
At that time, they found that it was effective to use a polybutylene terephthalate resin having a specific terminal group in a specific amount or more, and completed the present invention. That is, the present invention provides (A) 100 to 100 parts by weight of a polybutylene terephthalate resin having a terminal carboxyl group content of 30 meq / kg or more, (B) 3 to 100 parts by weight of an epoxy group-modified polypropylene resin, and (C) A polybutylene terephthalate resin composition containing 0.001 to 2 parts by weight of an agent.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, each component constituting the composition of the present invention will be described. The polybutylene terephthalate resin (A) used in the present invention is a polyester composed of terephthalic acid as a dicarboxylic acid component and 1,4-butanediol as a diol component and obtained by a polycondensation reaction or the like. In recent years, one or both of dicarboxylic acids and diols, both of which are composed of two or more kinds of components, are also common, and oxycarboxylic acids can be used as the third component. Examples of dicarboxylic acid compounds used here include known dicarboxylic acids such as isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylethanedicarboxylic acid, cyclohexanedicarboxylic acid, adipic acid, sebacic acid and these. Alkyl-, alkoxy-, or halogen-substituted products. These dicarboxylic acid compounds containing terephthalic acid can also be used for polymerization in the form of an ester-forming derivative, for example, a lower alcohol ester such as dimethyl ester.
Next, examples of dihydroxy compounds include ethylene glycol, propylene glycol, neopentyl glycol, hydroquinone, resorcinol, dihydroxyphenyl, naphthalene diol, dihydroxydiphenyl ether, cyclohexanediol, 2,2-bis (4-hydroxyphenyl) propane, and diethoxy. And dihydroxy compounds such as bisphenol A, polyoxyalkylene glycols and their alkyl, alkoxy or halogen substituents. Examples of the oxycarboxylic acid include oxycarboxylic acids such as oxybenzoic acid, oxynaphthoic acid, and diphenyleneoxycarboxylic acid, and substituted alkyl, alkoxy and halogen thereof. Further, derivatives of these compounds capable of forming an ester can also be used. In the present invention, one or more of these compounds can be used. Further, in addition to these, polybutylene terephthalate ester having a branched or cross-linked structure using a small amount of a trifunctional monomer, that is, trimellitic acid, trimesic acid, pyromellitic acid, pentaerythritol, trimethylolpropane, or the like may be used. Also,
Halogen compounds on aromatic nuclei such as dibromoterephthalic acid, tetrabromoterephthalic acid, tetrachloroterephthalic acid, 1,4-dimethyloltetrabromobenzene, tetrabromobisphenol A, and ethylene or propylene oxide adduct of tetrabromobisphenol A; Also included are polyester copolymers having a halogen as a substituent and using a compound having an ester-forming group. Further, a polyester elastomer constituting a block copolymer of a high melting point hard segment and a low melting point soft segment can also be used. Examples of the polyester elastomer include a block copolymer of a hard segment mainly composed of an alkylene terephthalate unit and a soft segment composed of an aliphatic polyester or polyether. In the present invention,
As long as terephthalic acid and butanediol are the main components, any of the above compounds can be used as a comonomer component and any thermoplastic polyester produced by polycondensation can be used as the component (A) of the present invention. Further, a polyester composed of only the above-mentioned monomer and polybutylene terephthalate can be used as a mixture.

In the present invention, among the polybutylene terephthalate resins as described above, the terminal carboxyl group content must be 30 meq / kg or more in order to sufficiently exert the effects of the present invention, but preferably 35 to 45 meq / kg. It is 100 meq / kg, more preferably 40-80 meq / kg. When using a polybutylene terephthalate resin having a terminal carboxyl group content of less than 30 meq / kg, the reaction of the epoxy group does not proceed sufficiently,
Desired weld characteristics cannot be obtained. However, when the amount is excessively large, autocatalytic decomposition or the like by the carboxylic acid group may occur, and the amount is preferably 100 meq / kg or less.
Further, since the total number of terminals is large in a low molecular weight polyester resin, the ratio of carboxylic acid terminals tends to be relatively small even at the same concentration. Therefore, the ratio of the carboxylic acid terminal to all terminals is preferably 40% or more.
The amount of such terminal carboxyl groups in the polyester resin can be determined by a known method. For example, a method in which a pulverized sample of polybutylene terephthalate resin is dissolved in benzyl alcohol by heating at 215 ° C. for 10 minutes, and then titrated with a 0.01 N sodium hydroxide solution for measurement.

Next, as the epoxy group-modified polypropylene resin (B) used in the present invention, any resin in which an epoxy group is bound to a polypropylene chain by a covalent bond can be used. Further, a polymer chain obtained by copolymerizing a monomer other than propylene can be used, and examples thereof include a propylene-ethylene copolymer and a propylene-ethylene-diene copolymer. It is also possible to mix and use these. Examples of the epoxy group-containing monomer component constituting the epoxy group-modified polypropylene resin (B) include glycidyl acrylate, glycidyl methacrylate, 4,5
-Epoxybenzyl acrylate, 4,5-epoxybenzyl methacrylate, allyl glycidyl ether, methacryl glycidyl ether, butadiene monoepoxide, etc., and glycidyl acrylate and glycidyl methacrylate are particularly preferably used.
As the amount of the epoxy-containing monomer added,
It is preferably in the range of 0.1 to 15% by weight, more preferably 0.1% by weight.
5 to 10% by weight. If the amount is too small, peeling and physical properties decrease due to insufficient compatibility with the polybutylene terephthalate resin. If the amount is too large, the melt viscosity of the polybutylene terephthalate resin composition is remarkably increased to deteriorate moldability. Further, an aromatic vinyl compound can be copolymerized in the epoxy group-modified polypropylene resin as long as the properties are not deteriorated. For example, styrene, methylstyrene, vinyltoluene, vinylxylene, ethylbenzene, isopropylstyrene, chlorostyrene and the like can be mentioned, and these are used alone or as a mixture.

[0008] The method for producing the epoxy group-modified polypropylene resin is not particularly limited, but generally two methods are known. One is a method in which an epoxy group-containing monomer and a radical initiator such as a polypropylene resin and a peroxide are mixed and melt-mixed using a Banbury mixer or an extruder. Another method is a method of mixing and copolymerizing an epoxy group-containing monomer with propylene and, if necessary, other olefin monomers.
Examples of such a radical initiator include dicumyl peroxide, t-butylcumyl peroxide, 2,5-dimethylhexane-2,5-dihydroperoxide, di-t-butyl peroxide, and t-butylcumyl peroxide. Oxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-
(Butylperoxy) hexyne-3, n-butyl-4,4-
Bis (t-butylperoxy) valerate, 2,3-dimethyl-2,3-diphenylbutane, 2,3-diethyl-2,3
-Diphenylbutane, 2,3-dimethyl-2,3-di (p-
Methylphenyl) butane, 2,3-dimethyl-2,3-di (bromophenyl) butane and the like can be mentioned, and two or more kinds can be used in combination. The amount of this radical initiator added is
The amount is 0.01 to 1.5 parts by weight, preferably 0.1 to 1.0 part by weight, per 100 parts by weight of the polyolefin resin. If the amount of the radical initiator to be added is too small, the modification of the polyolefin resin becomes insufficient, the effect of improving the compatibility between the polyester and the modified polypropylene resin is small, and the effect of the present invention is hardly obtained. On the other hand, an excessively large amount is not preferable because foaming may occur at the time of denaturation of the polypropylene resin, which may cause inconvenience. The amount of the epoxy group-modified polypropylene resin (B) used in the present invention is 3 to 100 parts by weight, preferably 5 to 90 parts by weight, more preferably 7 to 100 parts by weight based on 100 parts by weight of the polybutylene terephthalate resin (A). 85 parts by weight. When the amount is less than 3 parts by weight, the effect of adding polypropylene does not appear, and when the amount is more than 100 parts by weight, the flowability and strength of the polyester resin composition are lowered, which is not preferable.

Next, in the present invention, an epoxy reaction accelerator is added as the component (C). As such an epoxy reaction accelerator, those known as reaction catalysts for epoxy compounds, that is, any of various bases and acids can be used, and tertiary amines, tertiary amine salts, imidazole compounds, imidazole salts, and phosphonium salts are preferred. , An organometallic complex. Examples of tertiary amines include dimethylbenzylamine, trihexylamine, and 2,4,6-tris (dimethylaminomethyl) phenol, and examples of tertiary amine salts include tetramethylammonium chloride and trimethylbenzylammonium chloride. And the like, as examples of imidazole compounds, 2-methylimidazole, 2-phenyl-4
-Methyl imidazole, cyanoethylated imidazole and the like, as examples of imidazole salts, salts of the above imidazole compounds and trimellitic acid or isocyanuric acid,
Examples of phosphonium salts include ethyltriphenylphosphonium iodide, tetrabutylphosphonium bromide, tetrabutylphosphonium benzotriazolate, and the like.Examples of organometallic complexes include dibutyltin dilaurate. . Among these,
Tertiary amine salts, phosphonium salts, and organometallic complexes are highly effective and are preferably used. The amount of the epoxy reaction accelerator (C) to be added is 0.001 to 2 parts by weight, preferably 0.005 to 1 part by weight, per 100 parts by weight of the polybutylene terephthalate resin (A). If the amount of the accelerator is less than 0.001 part by weight, the improvement of the weld property is insufficient, and if it exceeds 2 parts by weight, the deterioration of the physical properties due to side reactions and the like cannot be ignored.

In the resin composition of the present invention, it is possible to use a small amount of another thermoplastic resin in a supplementary manner as long as its purpose is not impaired. For example, polyamide, polyacetal, polystyrene, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-butadiene-acrylonitrile copolymer, styrene-butadiene-acrylic acid (or ester thereof) copolymer, polycarbonate, polyurethane, Polyphenylene oxide,
It is also possible to mix copolymers (including multi-layer graft copolymers) mainly composed of polyphenylene sulfide, polybutadiene, halogenated polyolefin, polyvinyl halide, butyl rubber, polyacrylate, etc. at any ratio according to the purpose. It is.

In order to further impart desired characteristics to the composition of the present invention, known materials generally added to thermoplastic resins and thermosetting resins, such as antioxidants and heat stabilizers, ultraviolet rays Stabilizers such as absorbents, antistatic agents,
Of course, it is also possible to blend a coloring agent such as a dye or a pigment, a lubricant, a plasticizer, a crystallization accelerator, a crystal nucleating agent, and the like.

The composition of the present invention may preferably contain an inorganic or organic fibrous reinforcing agent and an inorganic filler depending on the purpose. As the fibrous reinforcing agent, glass fiber,
Examples thereof include general inorganic fibers such as carbon fiber, ceramic fiber, boron fiber, potassium titanate fiber, and asbestos, and organic fibers such as aramid fiber. Also, as an inorganic filler,
Calcium carbonate, highly dispersible silicate, alumina, aluminum hydroxide, talc, clay, mica, glass flake, glass powder, glass beads, quartz powder, silica sand, wollastonite, carbon black, barium sulfate, plaster of Paris,
Examples include powdery and granular substances such as silicon carbide, alumina, boron nitrite and silicon nitride, and plate-like inorganic compounds. These inorganic fillers can be used alone or in combination of two or more as necessary.

The composition of the present invention can be easily prepared by known equipment and methods generally used as a conventional method for preparing a resin composition. For example, i) a method of kneading and extruding with an extruder to prepare pellets after mixing each component, and then forming the pellets, and ii) once preparing pellets having a different composition, mixing the pellets in a predetermined amount and molding. Any method can be used, such as a method of obtaining a molded article having a desired composition after the molding, and iii) a method of directly charging each component in a molding machine. Mixing and adding a part of the resin component as a fine powder with other components is a preferable method for uniformly blending these components. Further, as long as such a filler does not inhibit the reaction between the polyester resin and the epoxy compound, it is also possible to add these at any time before or during the reaction to obtain a desired composition. .

[0014]

As is clear from the examples, the composition of the present invention can provide a molded article having excellent mechanical properties and moldability and extremely excellent weld properties.

[0015]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.
In addition, the measuring method of the physical property evaluation shown in the following examples is as follows. Tensile strength and elongation Tensile test pieces were molded using a test piece mold specified by ASTM, and the tensile strength and tensile elongation were measured in accordance with ASTM D-638. Weld part tensile strength and elongation The test piece specified in ASTM is molded using a mold with a weld line at the center, and the tensile strength and tensile elongation are measured according to ASTM D-6.
Measured according to 38. Izod impact strength Notched Izod impact strength was measured according to ASTM D-256. Production Example 1 (Production of Epoxy-Modified Polypropylene) 100 parts by weight of polypropylene (PP) (Nobrene manufactured by Sumitomo Chemical Co., Ltd.), 5 parts by weight of glycidyl methacrylate, and 2,5-dimethyl-2,5- as a radical initiator Di (t-butylperoxy) hexane is 0.15 to PP.
The mixture was premixed with a Henschel mixer for 5 minutes. The obtained mixture was supplied to an extruder and melt-kneaded at a temperature of 200 ° C. to obtain epoxy-modified polypropylene pellets.

Example 1 100 parts by weight of polybutylene terephthalate (manufactured by Polyplastics Co., Ltd., trade name: Duranex) A-1 were mixed with the epoxy group-modified polypropylene of Production Example 1 described above, and tetrabutyl was further added. Phosphonium bromide (C-1) was added in the amounts shown in Table 2 and mixed using a rocking mixer, followed by kneading and extrusion using a 30 mm extruder to prepare pellets. Next, the pellet was further injection molded to obtain a test piece. Table 2 shows the characteristic evaluation results. Examples 2 to 10 Except that the materials shown in Table 1 were mixed in the proportions shown in Table 2, pellets were prepared in the same manner as in Example 1, and the same evaluation was performed. Table 2 shows the results. Comparative Examples 1 to 7 Except that the materials shown in Table 1 were mixed in the proportions shown in Table 3, pellets were prepared in the same manner as in Example 1, and the same evaluation was performed. Table 3 shows the results.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

[Table 3]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI C08L 23:26) C08L 23:26)

Claims (5)

(57) [Claims] (1) 100 parts by weight of a polybutylene terephthalate resin having a terminal carboxyl group content of 30 meq / kg or more, (B) 3 to 100 parts by weight of an epoxy group-modified polypropylene resin, and (C) an epoxy reaction accelerator A polybutylene terephthalate resin composition containing 0.001 to 2 parts by weight. 2. The polybutylene terephthalate resin composition according to claim 1, wherein the amount of terminal carboxyl groups in the polybutylene terephthalate resin (A) is 40 to 80 meq / kg. 3. The polybutylene terephthalate resin composition according to claim 1, wherein the carboxylic acid terminal ratio of the component (A) in the polybutylene terephthalate resin is at least 40 mol% of all terminals. 4. The epoxy reaction accelerator of component (C) is at least one compound selected from the group consisting of tertiary amine salts, phosphonium salts, and organometallic complexes.
4. The polybutylene terephthalate resin composition according to any one of 3. 5. The method according to claim 1, wherein the heating and melting treatment is carried out for at least 30 seconds in the presence of at least the components (A), (B) and (C).
5. The method for producing a polybutylene terephthalate resin composition according to any one of claims 1 to 4.