JPH11222550A - Polypropylene terephthalate resin molding having weld - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin molding excellent in thin-wall rigidity, thin-wall impact resistance, especially, thin-wall weld strength, and excellent in the hydrolysis resistance of the weld under high-temperature high-humidity conditions by providing a weld comprising a polypropylene terephthalate resin. SOLUTION: The polypropylene terephthalate resin (PT resin) used is a thermoplastic polyester prepared from an acid component being terephthalic acid and a glycol component being 1,3-propylene glycol. It is desirable that 100 pts.wt. PT resin is mixed with 5-100 pts.wt. elastomer (e.g. olefinic elastomer) having a glass transition temperature of 20 deg.C or below, and the mean particle diameter of the disperse phase comprising the elastomer is 20 μm or below. It is desirable that 0.01-5 pts.wt. epoxy compound (e.g. diepoxy compound) is added to 100 pts.wt. PT resin. It is desirable that 0.01-20 pts.wt. nucleator (e.g. talc) is used per 100 pts.wt. PT resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded article of polypropylene terephthalate resin which is excellent in thin-wall rigidity, thin-wall impact characteristics, and hydrolysis resistance, and especially excellent in thin-wall weld strength.

[0002]

2. Description of the Related Art Thermoplastic polyesters represented by polybutylene terephthalate are used in a wide range of fields such as automobiles, electric and electronic parts due to their excellent moldability, mechanical properties, heat resistance, chemical resistance, weather resistance, and electrical properties. Have been. However, in recent years, with respect to electric / electronic parts and OA equipment, with the miniaturization and integration of electric equipment, the thickness of molded articles and the shape of molded articles have become more complicated. As a result, the number of thin-walled molded products having a weld portion has increased. The weld portion is a portion where two or more resin flow front interfaces merge and fuse in the mold cavity during molding, but the mechanical properties of the weld portion of the weld portion are significantly reduced. Have a point. In particular, when molding a molded article having a complicated shape, injection molding is often performed by providing two or more gates in the mold cavity of the molded article. Formation is inevitable, and a decrease in the mechanical properties of the weld portion is inevitable.

[0003] With respect to thermoplastic polyesters as well, with the miniaturization and integration of electrical equipment, the thickness of molded products and the shape of molded products have become more complicated, and the number of thin molded products having welds has increased, resulting in thin rigidity. Therefore, there has been a strong demand for improved thin wall impact characteristics and weld strength. In addition, when the obtained molded product is used for an automobile, etc., since the use conditions are severe conditions such as high temperature and high humidity, the thin rigidity,
In addition to the thin impact characteristics and weld strength, characteristics such as hydrolysis resistance have been required.

As a means for improving the hydrolysis resistance, a method of blending an aromatic polycarbonate or a glycidyl group-containing copolymer with a polyester resin as disclosed in Japanese Patent Application Laid-Open No. 60-231557 is a means for improving impact characteristics. JP-A-57-100154 discloses a method of blending a vinyl polymer or a glycidyl group-containing vinyl copolymer, and JP-A-61-283653 discloses a method of blending a modified polyolefin. It has been disclosed.

[0005]

However, Japanese Patent Application Laid-Open No.
According to the method disclosed in Japanese Patent No. 231557, when a molded article having a welded portion is treated under high temperature and high humidity, deterioration of the molded article occurs from the welded portion, and the molded article does not sufficiently satisfy the recent required characteristics. Did not. Further, this technique did not improve thin-wall rigidity and thin-wall impact characteristics. Japanese Patent Application Laid-Open Nos. Sho 57-100154 and Sho 61-283
The method disclosed in Japanese Patent Application Publication No. 653 also has a problem that when the treatment is performed under high temperature and high humidity, the weld portion is deteriorated. Further, although the thin-wall impact characteristics are improved to some extent by this technique, there is a problem that the initial rigidity is reduced.

An object of the present invention is to solve the above-mentioned problems and to obtain a molded article excellent in thin-wall rigidity and thin-wall impact characteristics, especially in thin-wall weld strength and hydrolysis resistance of a thin-wall weld portion. .

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, among the polyester resins,
In particular, polypropylene terephthalate resin has thin rigidity,
The inventors of the present invention have noticed that the thin impact properties, particularly the mechanical properties of the thin weld portion, are excellent, and arrived at the present invention.

That is, the present invention is a molded article having a weld portion made of a polypropylene terephthalate resin.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The resin composition of the present invention will be specifically described below.

[0010] The molded article having a weld portion of the present invention can be obtained by molding a polypropylene terephthalate resin.

The polypropylene terephthalate resin of the present invention refers to a thermoplastic polyester using terephthalic acid as an acid component and 1,3-propylene glycol as a glycol component. As an acid component, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, oxalic acid, adipic acid, 1,4
-Cyclohexanedicarboxylic acid and the like, and ethylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, ethylene oxide adduct of bisphenol-A and the like are partially used as a glycol component. be able to.

The copolymerization amount in the case of copolymerization is not particularly limited as long as the object of the present invention is not impaired.
30 mol% or less of the acid component or 3 of the glycol component
It is preferably at most 0 mol%.

The method for producing the polypropylene terephthalate resin used in the present invention is not particularly limited, and it can be produced according to a known polyester polycondensation method.

Although the molecular weight of such a polyester resin is not particularly limited, the intrinsic viscosity (dl / g) measured at 25 ° C. using a mixed solution of phenol / tetrachloroethane = 1/1 is usually 0.10. ~ 3.00 can be used, but is preferably 0.25 to 2.50, particularly preferably 0.40 to 2.25.

Further, the molded article having a weld portion of the present invention can improve the thin impact characteristics and the decrease in mechanical strength due to the deterioration of the connector under high temperature and high humidity when an elastomer having a glass transition temperature of 20 ° C. or less is added. it can.

There is no particular limitation as long as the elastomer has a glass transition temperature of 20 ° C. or lower, but olefin elastomers, nylon elastomers, polyester elastomers, polyester polyether elastomers, polyester polyester elastomers, polyester polyamide elastomers, and the like can be used. Preferably, olefin elastomers and polyester polyether elastomers are particularly preferred, and olefin elastomers are particularly preferred. Specific examples of such olefin-based elastomer include ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene / propylene / conjugated diene copolymer, ethylene / ethyl acrylate copolymer, ethylene / methacrylic Acid copolymer, ethylene / glycidyl methacrylate copolymer, ethylene / vinyl acetate / glycidyl methacrylate copolymer, ethylene /
Ethyl acrylate-g-maleic anhydride copolymer, ethylene / methyl methacrylate-g-maleic anhydride copolymer, ethylene / ethyl acrylate-g-maleimide copolymer, ethylene / ethyl acrylate-g-N -Phenylmaleimide copolymer, ethylene / propylene-g-maleic anhydride copolymer, ethylene / butene-1-g-maleic anhydride copolymer, ethylene / propylene / 1,4-
Hexadiene-g-maleic anhydride copolymer, ethylene / propylene / dicyclopentadiene-g-maleic anhydride copolymer, ethylene / propylene / 2,5-norbornadiene-g-maleic anhydride copolymer, ethylene /
Propylene-g-N-phenylmaleimide copolymer, styrene / maleic anhydride copolymer, styrene / butadiene / styrene-g-maleic anhydride block copolymer,
After hydrogenating a styrene / butadiene / styrene block copolymer, styrene / ethylene / butylene / styrene-g-maleic anhydride block copolymer obtained by grafting maleic anhydride, styrene / isoprene-
g-maleic anhydride block copolymer, ethylene / acrylic acid ionomer, ethylene / methacrylic acid ionomer, ethylene / itaconic acid ionomer and the like can be used, and each of them can be used alone or in the form of a mixture.

Such olefin-based elastomers may further have a hydroxyl group, a carboxylic acid group, a carboxylic acid ester group, a carboxylic acid metal group in the polymer molecule or at the terminal of the polymer for the purpose of improving the compatibility with the polypropylene terephthalate resin. It is also possible to use a polyolefin elastomer in which at least one kind of functional group among bases, carboxylic anhydride groups, imide groups and the like is chemically bonded.

Alternatively, these olefin-based elastomers may be used to improve the compatibility with polypropylene terephthalate at the time of melt-kneading acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, methyl maleic acid, Methyl fumaric acid, mesaconic acid,
Citraconic acid, glutaric acid and metal salts of these carboxylic acids, methyl hydrogen maleate, methyl hydrogen itaconate,
Methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, hydroxyethyl acrylate, methyl methacrylate, methyl methacrylate, 2-ethylhexyl methacrylate, hydroxyethyl methacrylate, amino methacrylate ethyl,
Dimethyl maleate, dimethyl itaconate, maleic anhydride, itaconic anhydride, citraconic anhydride, endobicyclo- (2,2,1) -5-heptene-2,3-dicarboxylic acid, endobicyclo- (2,2, 1) -5-Heptene-2,3-dicarboxylic anhydride, maleimide, N-ethylmaleimide, N-butylmaleimide, N-phenylmaleimide, glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, glycidyl itaconate, citracone By adding glycidyl acid or the like, the olefin-based elastomer or polypropylene terephthalate can be chemically modified.

In the present invention, the amount of the elastomer having a glass transition temperature of 20 ° C. or less is usually 5 to 100 parts by weight, preferably 10 to 60 parts by weight, more preferably 100 parts by weight of the polypropylene terephthalate resin. Is 15 to 40 parts by weight.

When a relatively small amount of an elastomer is used, the elastomer in the resin composition is present as a dispersed phase in a polypropylene terephthalate resin as a matrix. In order for the molded article obtained by the composition of the present invention to have more excellent impact strength, it is desirable that it is finely dispersed. One of the methods for evaluating the mixing state in the resin composition is a method using the particle size of the dispersed phase as an evaluation scale.When an elastomer is blended in the resin composition of the present invention, the dispersion average of the elastomer portion is determined by the elastomer. Is preferably 20 microns or less, more preferably 1 μm or less.
0 microns or less.

Further, an epoxy compound can be further compounded for the purpose of improving the impact resistance and hydrolysis resistance of the molded article made of the resin of the present invention.

The epoxy compound is not particularly limited as long as it is an epoxy compound containing an epoxy group in the molecule, but is preferably a monoepoxy compound, a diepoxy compound, or a triepoxy compound, and particularly preferably a diepoxy compound. it can. Specific examples of such diepoxy compounds include the following general formulas (1), (2),
The diepoxy compounds represented by (3), (4), (5), (6), (7), and (8) can be used.

[0023]

Embedded image (N represents an integer of 1 or more.) The amount of the epoxy compound to be added is usually 0.1 to 100 parts by weight of the polypropylene terephthalate resin.
The amount is from 0.01 to 5 parts by weight, preferably from 0.05 to 3 parts by weight, more preferably from 0.2 to 1 part by weight.

The molded article having a weld portion according to the present invention may contain a filler for the purpose of improving thin-wall rigidity and heat resistance. Such fillers include glass fiber, carbon fiber, metal fiber, aramid fiber, asbestos,
Examples include potassium titanate whiskers, aluminum borate whiskers, wollastenite, glass flakes, glass beads, and the like.

In the above-mentioned filler, glass fibers are preferably used. The type of glass fiber is not particularly limited as long as it is generally used for reinforcing a resin, and for example, it can be selected from long fiber type or short fiber type chopped strand, milled fiber and the like.

The amount of the filler of the present invention is usually from 1 to 2 per 100 parts by weight of the polypropylene terephthalate resin.
00 parts by weight, preferably 5 to 150 parts by weight, more preferably 10 to 100 parts by weight.

Further, when a crystal nucleating agent is added to the polypropylene terephthalate resin molded article having a weld portion according to the present invention, the thin rigidity is improved.

The nucleating agent of the present invention is not particularly limited as long as it is a compound which promotes crystallization of the polypropylene terephthalate resin. Talc, mica, kaolin, silica, clay, inorganic carboxylate, inorganic sulfonate , Metal oxides, carbonates, organic carboxylates, organic sulfonates and the like are preferably used, and among them, talc, mica and kaolin are particularly preferably used.

The amount of the nucleating agent of the present invention is usually 0.1 to 100 parts by weight of the polypropylene terephthalate resin.
01 to 20 parts by weight, preferably 0.02 to 15 parts by weight,
More preferably, it is 0.03 to 10 parts by weight.

Further, the polypropylene terephthalate resin molded article having a welded portion of the present invention may contain an antioxidant such as a hindered phenol-based, phosphorus-based or sulfur-based antioxidant or a heat-stable agent within a range not to impair the object of the present invention. Agent,
UV absorbers (eg resorcinol, salicylate,
Benzotriazole, benzophenone, etc.), lubricants and mold release agents (montanic acid and its salts, esters, half esters thereof, stearyl alcohol, stearamide and ethylene wax, etc.), coloring inhibitors (phosphites, hypophosphorous acid) Salt, etc.), nucleating agents, plasticizers, flame retardants,
One ordinary additive such as an antistatic agent and a coloring agent containing a dye / pigment (cadmium sulfide, phthalocyanine, etc.)
More than one species can be added. Further, the resin composition of the present invention is produced by a generally known method. For example, it is prepared by premixing a polypropylene terephthalate resin, a filler and other necessary additives with or without pre-mixing and feeding the extruder or the like, and sufficiently melting and kneading in a temperature range of 230 ° C to 280 ° C. You. In this case, for example, a single-screw extruder, a twin-screw extruder, a kneader of a kneader type, or the like having a “unimelt” type screw can be used. Particularly, since the aspect ratio is controlled, the screw is kneaded. It is preferable to use a plurality of coding elements by inserting or not inserting them. The molded article having a weld portion of the present invention can be easily obtained by injection molding the above-mentioned polypropylene terephthalate resin or polypropylene terephthalate resin composition by a generally known method, for example, injection molding, extrusion molding, compression molding and the like. Moldings, sheets,
It can be a molded article such as a film. Among them, it is particularly suitable for use in an injection molded product having a weld portion, and can be effectively used as a mechanical mechanism component, an electric / electronic component, an OA device component, and an automobile component by utilizing its features.

For example, various gears, various cases, sensors, LEP lamps, connectors, sockets, resistors, relay case switch coil bobbins, capacitors, variable condenser cases, optical pickups, oscillators, various terminal boards, transformers, plugs, printed wiring Electric / electronics represented by boards, tuners, speakers, microphones, headphones, small motors, magnetic head bases, power modules, housings, semiconductors, liquid crystals, FDD carriages, FDD chassis, motor brush holders, parabolic antennas, computer-related parts, etc. Parts; VTR
Parts, TV parts, irons, hair dryers, rice cooker parts, microwave parts, audio parts, audio equipment parts such as audio / laser discs / compact discs, lighting parts, refrigerator parts, air conditioner parts, typewriter parts, word processor parts, etc. Home and office electrical product parts, office computer related parts, telephone related parts, facsimile related parts, copier related parts, cleaning jigs, various bearings such as oilless bearings, stern bearings, underwater bearings, and motor parts. , Lighter, typewriter, etc., machinery-related parts, microscopes, binoculars, cameras, watches, etc., optical equipment, precision machinery-related parts; alternator terminal, alternator connector, IC regulator, potentiometer Scan, various valves such as exhaust gas valve, fuel related-exhaust system, an intake system various pipes, air intake nozzle snorkel, intake manifold,
Fuel pump, engine cooling water joint, carburetor main body, carburetor spacer, exhaust gas sensor, cooling water sensor, oil temperature sensor, brake pad wear sensor, throttle position sensor,
Crankshaft position sensor, air flow meter, brake butt wear sensor, thermostat base for air conditioner, heating hot air flow control valve, brush holder for radiator motor, water pump impeller, turbine vane, wiper motor related parts, dust distributor, starter Switch, starter relay, transmission wire harness, window washer nozzle, air conditioner panel switch board, fuel related electromagnetic valve coil, fuse connector, horn terminal, electrical component insulation board,
Step motor rotor, lamp socket, lamp reflector, lamp housing, brake piston, solenoid bobbin, engine oil filter, ignition device case, personal computer, printer, display, CRT
Electrical and electronic equipment parts such as display, fax, copy, word processor, notebook computer, DVD drive, PD drive, storage device housing such as floppy disk drive, relay, switch, case member, transformer member, coil bobbin, OA equipment part, It is useful for automotive parts, mechanical mechanism parts, and various other uses. In particular, it is suitable for connectors and housings having a weld portion among the above-mentioned applications because of its features such as thin rigidity, thin impact characteristics, thin weld strength, and hydrolysis resistance of the weld portion.

[0032]

The present invention will be described more specifically below with reference to examples and comparative examples.

The properties described in Examples and Comparative Examples were measured by the following methods.

<Evaluation Items> Tensile strength: Measured according to ASTM-D638 using a tensile dumbbell having a molded product thickness of 1 mm.

Bending modulus: ASTM D790
Therefore, it was measured.

Impact resistance: molded product thickness 1/8 '
Was measured according to ASTM-D256 using an impact test piece of

Weld strength test: An ASTM No. 4 tensile test piece was molded using a mold having gates at both ends of the test piece. The tensile strength of the obtained test piece was measured based on ASTM-D638.

Hydrolysis resistance: An ASTM No. 4 tensile test piece was molded using a mold having gates at both ends of the test piece, and the obtained test piece was subjected to a temperature of 121 ° C. and 100 RH%.
The tensile strength of the sample left for 1000 hours was measured, and the tensile strength retention was calculated from strength retention = after treatment / before treatment × 100 (%).

The polypropylene terephthalate used in the present invention was produced by the following method.

Reference Example 1 Production of polypropylene terephthalate 2.0 kg of terephthalic acid was placed in a 5 liter autoclave.
1.3 kg of 1,3-propylene glycol was weighed, and the internal temperature of the autoclave was set at 180 ° C. When the internal temperature reached 120 ° C., 2.0 g of tetrabutyl titanate and 2.0 g of monohydroxytin oxide were added.
Stirred at 0 ° C. for 1 hour. Then 250 ° C over 2 hours
At the same time, the pressure was reduced to 0.5 mmHg. Thereafter, the reaction was carried out for about 1 hour, and when the torque became constant, the polymer was discharged. The intrinsic viscosity measured at 25 ° C. using a mixed solvent of phenol / tetrachloroethane = 1/1 was 1.3.

The resin compositions used in the examples and comparative examples were produced by the following method, and measurement samples were prepared by injection molding.

The thermoplastic resin (A), the polypropylene terephthalate (B) produced in the reference example, and other necessary additives were mixed and melt-kneaded at a melting point of the thermoplastic resin + 30 ° C. using a 30 mmφ twin screw extruder. . After the obtained pellets are dried, they are supplied to a Sumitomo Nestal injection molding machine / Promat 40/25 (manufactured by Sumitomo Heavy Industries, Ltd.),
Cylinder temperature: polymer melting point + 30 ° C, mold temperature 80
Molded under the condition of ° C.

The thermoplastic polyester resin and other additives used in the examples are as follows.

Polybutylene terephthalate (PB)
T): Toray PBT1100S (manufactured by Toray Industries, Inc.) was used.

An elastomer having a glass transition temperature of 20 ° C. or less: Glycidyl methacrylate-modified copolymerized polyethylene (“Bond First” EPX-6, manufactured by Sumitomo Chemical Co., Ltd.) was used.

Epoxy compound: A diepoxy compound represented by the following general formula (1) was used.

[0047]

Embedded image -Crystal nucleating agent: Talc "LMS-300, manufactured by Fuji Talc) was used.

Example 1 and Comparative Example 1 Resin pellets obtained in Reference Example were used with Sumitomo Nestal injection molding machine Promat 40/25 (manufactured by Sumitomo Heavy Industries, Ltd.).
, And each molded product was obtained by injection molding at 260 ° C. Table 1 shows the results.

The measurement results of Example 1 and Comparative Example 1 show that the polypropylene terephthalate resin is excellent in thin-wall rigidity and thin-wall impact characteristics, has excellent weld strength, and has a small decrease in weld strength due to high-temperature and high-humidity treatment. . On the other hand, it is understood that the polybutylene terephthalate resin is inferior in thin-wall rigidity, and further inferior in weld strength and in hydrolysis resistance of the weld portion.

Examples 2 and 3, Comparative Examples 2 and 3 The resin pellets obtained in Reference Examples and other additives were mixed with L / L
260-280 using a 30 mm twin screw extruder with D = 45
The mixture was melted and kneaded at a temperature of ° C to form pellets. After drying with hot air, the pellets are converted to Sumitomo Nestal injection molding machine Promat 40/2.
5 (manufactured by Sumitomo Heavy Industries, Ltd.).
Obtained by injection molding at 0 ° C.

In order to measure the dispersed particle size of the elastomer in the obtained resin composition, a thin piece was cut out from a test piece for evaluation using an ultramicrotome, and this was cut with an optical microscope (transmitted light) and a transmission electron microscope. Photographs were taken using a microscope, the major axis of 100 individuals selected at random from the micrograph was measured, and the average value was calculated. As a result, the dispersed particle size of the elastomer in the resin composition was extremely finely dispersed at 1.6 μm or less. Table 1 shows the results.

As shown in Examples 2 and 3, the addition of an elastomer, epoxy compound or crystal nucleating agent having a glass transition temperature of 20 ° C. or lower reduces the rigidity, weld strength and hydrolysis resistance. It can be seen that the thin impact strength is improved. On the other hand, when an elastomer or an epoxy compound having a glass transition temperature of 20 ° C. or lower is similarly added to PBT, the thin-wall impact characteristics are certainly improved, but the thin-wall rigidity, weld strength, and hydrolysis resistance of the weld portion are inferior. You can see that.

[0053]

[Table 1]

[0054]

The molded article made of the polypropylene terephthalate resin having a weld portion according to the present invention is excellent in thin-wall rigidity and thin-wall impact characteristics, especially excellent in thin-wall weld strength, and also excellent in hydrolysis resistance of the weld portion under high temperature and high humidity. I have.

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Claims (9)

[Claims] 1. A molded article of a polypropylene terephthalate resin having a weld portion made of a polypropylene terephthalate resin. 2. Polypropylene terephthalate resin 100
The polypropylene terephthalate resin molded article having a weld portion according to claim 1, wherein 5 to 100 parts by weight of an elastomer having a glass transition temperature of 20 ° C or less is blended with respect to parts by weight. 3. A molded article of polypropylene terephthalate resin having a weld portion according to claim 2, wherein the elastomer having a glass transition temperature of 20 ° C. or lower is an olefin-based elastomer. 4. The polypropylene terephthalate resin matrix phase according to claim 2, wherein a dispersed phase comprising an elastomer having a glass transition temperature of 20 ° C. or less is present, and the average particle size of the dispersed phase is 20 μm or less. A molded product of polypropylene terephthalate resin having a weld portion. 5. Polypropylene terephthalate resin 100
The polypropylene terephthalate resin molded product having a weld portion according to any one of claims 1 to 4, wherein the epoxy compound is contained in an amount of 0.01 to 5 parts by weight with respect to parts by weight. 6. Polypropylene terephthalate resin 100
The polypropylene terephthalate resin molded article having a weld portion according to any one of claims 1 to 5, wherein the nucleating agent is contained in an amount of 0.01 to 20 parts by weight based on part by weight. 7. The nucleating agent is talc, mica, kaolin,
The weld according to claim 6, which is one or a mixture of two or more selected from silica, clay, inorganic carboxylate, inorganic sulfonate, metal oxide, carbonate, organic carboxylate, and organic sulfonate. Polypropylene terephthalate resin molded product having a part. 8. The resin molded product may be a mechanical mechanism part, an electric part,
8. A molded article of a polypropylene terephthalate resin having a weld portion according to claim 1, which is an OA equipment part or an automobile part. 9. The polypropylene terephthalate resin article having a weld portion according to claim 1, wherein the resin article is a connector or a housing.