JPH0585581B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a composition of thermoplastic polyester resin (excluding polyester mainly composed of ethylene terephthalate repeating units) which has improved mechanical properties including impact resistance and heat resistance. Thermoplastic polyester, especially polybutylene terephthalate (hereinafter abbreviated as PBT), has well-balanced physical properties and excellent moldability, and is widely used in mechanical parts, electronic/electrical parts, automobile parts, and other fields. It's being used. However, while PBT has excellent properties, it also has the major drawback of low notched impact strength. That is, PBT exhibits good impact strength without a notch, but when a notch is added, the impact strength is significantly reduced. In practical terms, consideration has been given to eliminating sharp edges in the molded product design, but if the molded product is scratched and an impact is applied to it, it becomes susceptible to damage, which is an obstacle to expanding its uses. There is. In the past, various methods have been studied to improve the notched impact strength of PBT. -25261), method of blending polyether ester block copolymer (Japanese Patent Application Laid-Open No. 1983-25261),
48059), a method of blending an acrylic multiphase composite copolymer (JP-A-52-150466), a method of blending an α,β-unsaturated carboxylic acid graft-modified ethylene copolymer (JP-A-55-1999) 21430), but the effect of improving impact resistance is insufficient, or while impact resistance has been improved, mechanical properties such as tensile strength and bending strength, heat resistance stability,
Other useful properties such as weather resistance and moldability are significantly reduced, and the balance of the excellent properties of PBT is lost, resulting in unsatisfactory results. In particular, when we examine the behavior during heating and melting, we find that the melt stability during heating is poor and the change in melt viscosity is large, so if it remains in the molding machine for a slightly longer period of time, fluidity may decrease in some cases, resulting in short shots. In severe cases, molding defects such as gelation may occur, and in some cases, resin decomposition is accelerated and fluidity increases, resulting in molding defects such as increased burrs from the mold. In some cases, it was even observed that the impact resistance of the molded product decreased and it became brittle. In view of these current circumstances, the present inventors have developed a thermoplastic polyester resin composition that has significantly improved notched impact strength of thermoplastic polyester resins such as PBT, has stable melt viscosity, and maintains a good balance of physical properties. The present invention was developed after extensive research in order to obtain the desired product. That is, the present invention involves graft polymerization of (A) 95 to 50 parts by weight of a thermoplastic polyester resin (excluding polyesters mainly composed of ethylene terephthalate repeating units) and (B) 0.01 to 10% by weight of an unsaturated carboxylic acid or its anhydride. 5 to 50 parts by weight of a copolymer of ethylene and α-olefin having 3 to 6 carbon atoms and 0.1 to 10 parts by weight of (C) a polyepoxy compound (total of (A) and (B) 100 parts by weight)
The present invention provides a thermoplastic polyester resin composition obtained by melting (based on parts by weight). Here, the thermoplastic polyester resin
(A) means terephthalic acid or its esters;
Propylene glycol, butanediol, pentanediol, neopentyl glycol, hexanediol, octanediol, decanediol,
Cyclohexane dimethanol, hydroquinone,
Terephthalic acid obtained from glycols such as bisphenol A, 2,2-bis(4-hydroxyethoxyphenyl)propane, 1,4-dimethyloltetrabromobenzene or an ethylene oxide adduct of tetrabromobisphenol A. It usually has an intrinsic viscosity [η] of 0.3 to 0.3 when measured at 30°C in a mixed solvent of phenol and tetrachloroethane in a weight ratio of 6:4.
A range of 1.5 dl/g is used. In addition, less than 40 mol% of the total acid components are composed of isophthalic acid, orthophthalic acid, naphthalene dicarboxylic acid, 4,4'-diphenyldicarboxylic acid, diphenyl ether dicarboxylic acid, α,β-bis(4-
carboxyphenoxy)ethane, adipic acid, sebacic acid, azelaic acid, decanedicarboxylic acid,
other dicarboxylic acids such as cyclohexanedicarboxylic acid or dimer acid, or glycolic acid,
Hydroxycarboxylic acids such as hydroxybutyric acid, hydroxycaproic acid, hydroxybenzoic acid, hydroxyphenyl acetic acid or naphthyl glycolic acid may be substituted, while up to 40 mol% of the total glycol component may be replaced by polyethylene glycol or polytetramethylene. It may be replaced with polyalkylene ether glycols such as ether glycol or aliphatic polyester oligomers having hydroxyl groups at both ends. In addition, a lactone compound such as propiolactone, butyrolactone, valerolactone, or caprolactone or a polymer thereof may be contained as a comonomer component in an amount of 40 mol% or less in the total monomer component, or within a range that can maintain thermoplasticity. It may also contain polyfunctional ester-forming components such as trimethylolpropane, trimethylolethane, glycerin, pentaerythritol; trimellitic acid, trimesic acid, pyromellitic acid, and the like. Low molecular weight polyalkylene terephthalate with a hydroxyl group at the end ([η] = 0.1 to 0.5
Polyester polyurethanes obtained by increasing the molecular weight of dl/g) with polyfunctional isocyanates are also included in the present invention. Among these thermoplastic polyesters, polybutylene terephthalate exhibits particularly desirable effects. The impact modifier (B) used in the present invention is a copolymer of ethylene and α-olefin having 3 to 6 carbon atoms graft-polymerized with 0.01 to 10% by weight of an unsaturated carboxylic acid or its anhydride, Copolymers of ethylene and 3 to 6 carbon atoms (hereinafter referred to as ethylene copolymers) used as backbone polymers include:
A copolymer of ethylene and an α-olefin having 3 to 6 carbon atoms such as propylene, butene-1, isobutene, pentene-1, 4-methylpentene-1, hexene-1, or one or more other copolymers. Polymerizable monomers are copolymerized, specifically ethylene/propylene copolymer, ethylene/butene-1 copolymer, ethylene/4-methylpentene-
1 copolymer, ethylene/hexene-1 copolymer,
Ethylene/propylene/butene-1 copolymer, ethylene/propylene/4-methylpentene-1 copolymer, ethylene/propylene/hexene-1 copolymer, ethylene/propylene/ethylidene norbornene copolymer, ethylene/propylene/ Dicyclopentadiene copolymer, ethylene/butene
Examples thereof include 1/ethylidenenorbornene copolymer, ethylene/butene-1/dicyclopentadiene copolymer, and the like. In addition, unsaturated carboxylic acids or their anhydrides to be graft-polymerized to these ethylene copolymers include maleic acid, fumaric acid, itaconic acid, methylmaleic acid, and 3,6-endomethylene-delta-4-tetrahydrophthalic acid. , acrylic acid, methacrylic acid, crotonic acid, citraconic acid, maleic anhydride, itaconic anhydride, methylmaleic anhydride, 3,6-endomethylene-delta-4-tetrahydrophthalic anhydride, 2-methyl-3,6 −
Endomethylene-delta-4-tetrahydrophthalic anhydride, 3-methyl-4-cyclohexene-
Examples include 1,2-dicarboxylic acid anhydride. In addition to these unsaturated carboxylic acids or their anhydrides, derivatives of these acids such as esters, amides, imides, and nitriles may be used in combination. The polymerization reaction in which an unsaturated carboxylic acid or its anhydride is grafted onto the main ethylene copolymer is
It can be carried out by known means in a solution state, suspension state, slurry state or melt state. For example, an unsaturated carboxylic acid (anhydride) and an organic peroxide are added to a solution of an ethylene copolymer dissolved in a solvent such as toluene or hexane, graft polymerization is performed under heating and stirring, and then the solvent is removed or a non-solvent is added. Alternatively, a mixture of the ethylene copolymer, unsaturated carboxylic acid (anhydride), and organic peroxide is heated and melted using an extruder, kneader, etc. A method is used in which graft polymerization is performed during kneading. The amount of unsaturated carboxylic acid or its anhydride to be graft-polymerized is 0.01 to ethylene copolymer.
-10% by weight, preferably 0.1-7% by weight,
If this amount is too small, the effect of improving the impact on the thermoplastic polyester will be small, and if it is too large, the thermoplastic polyester resin composition will be colored or the melt viscosity will change greatly in the molten state, which is not preferable. The appropriate amount of the ethylene copolymer graft-polymerized with unsaturated carboxylic acid or its anhydride is 5 to 50 parts by weight out of the total 100 parts by weight of the thermoplastic polyester resin, and if it is less than 5 parts by weight, the impact resistance will be poor. There is almost no improvement effect, and on the other hand, if the amount exceeds 50 parts by weight, the excellent properties of the thermoplastic polyester resin will not be exhibited, and it can no longer be said to be the engineering plastic targeted by the present invention. However, although a composition consisting only of a thermoplastic polyester resin and an ethylene copolymer obtained by graft polymerization of an unsaturated carboxylic acid (anhydride) has some improvement in impact resistance, it has poor mechanical strength including bending strength. Also, since the melt viscosity decreases greatly during heating and melting, defective products are likely to occur during molding, and there are still many practical problems such as lack of stable moldability over a long period of time. In the present invention, after examining many compounds to solve these problems, it was discovered that the desired purpose could be achieved when a polyepoxy compound was used in combination, and the present invention was used to implement the present invention. The wet polyepoxy compound (C) has two or more epoxy groups in its molecule, and bisphenol A
diglycidyl ether, hydroquinone diglycidyl ether, resorcinol diglycidyl ether, 4,4'-biphenyl diglycidyl ether, 4,4'-diphenyl sulfone diglycidyl ether, triglycidyl ether of trihydroxyphenylpropane, tetrahydroxyphenyl ether Tetraglycidyl ether of enylethane, polyglycidyl ether of novolak, diethylene glycol diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, cyclooctadiene-(1,5)
-diepoxide, dicyclopentadiene diepoxide, bicycloheptadiene diepoxide, 1,
2,5,6-diepoxycyclododecane-9,
Examples include epoxidized soybean oil. Also included are oligomeric polyepoxy compounds obtained by addition polymerizing the above polyepoxy compounds and polyphenols or polyols. Polyepoxy necessary to significantly improve the mechanical strength of a thermoplastic polyester resin composition containing an ethylene copolymer graft-polymerized with an unsaturated carboxylic acid (anhydride) and to stabilize the melt viscosity under heating and melting. The compounding amount of the compound is determined according to the composition.
0.1 to 10 parts by weight per 100 parts by weight, preferably 1 to 10 parts by weight
8 parts by weight, and if it is less than 0.1 parts by weight, there is almost no improvement effect; on the other hand, if it is added more than 10 parts by weight, there is no improvement in the improvement effect, and on the contrary, mechanical properties and melt fluidity may deteriorate. There is also something undesirable. In the composition of the present invention, a small proportion of not more than 40% by weight of thermoplastic polyester resin may be used, for example, polyolefin, ionomer, polystyrene, AS resin, etc.
ABS resin, MBS resin, ASA resin, acrylic resin, vinyl acetate resin, vinyl chloride resin, ethylene-vinyl acetate copolymer, polyacetal, polycarbonate, polyester, polyurethane, polyamide, polysulfone, polyethersulfone or modified polyp-phene Mixtures substituted with other polymers such as nylene oxide or various organic polymers such as acrylic rubber graftomers, styrene-butadiene rubbers, ethylene-propylene rubbers, elastomers such as polyesterether elastomers or polyamideether elastomers. It may be a shape. Furthermore, the composition of the present invention includes glass fibers, potassium titanate fibers, metal fibers, ceramic fibers, calcium carbonate, calcium silicate, magnesium silicate, calcium sulfate, barium sulfate, iron oxide, graphite, carbon black, mica, asbestos, Including reinforcing fillers such as ceramics, metal flakes, glass beads or glass powders, nucleating agents, pigments, dyes, plasticizers, mold release agents, lubricants, heat stabilizers, antioxidants, UV absorbers, foaming. A flame retardant, a coupling agent, etc. may be used in combination. Thus, the composition of the present invention can be prepared, for example, by uniformly mixing all the ingredients fried above in advance, and then supplying the mixture to a single-screw or multi-screw extruder,
Melted at 300℃, kneaded, then cooled,
Prepared as pellets. The thermoplastic polyester resin composition of the present invention has significantly improved notched strength, stable melt viscosity, excellent moldability, and good balance of physical properties, so it has great industrial utility and In addition to conventional applications such as electronic parts, mechanical parts, automobile parts, and building material parts, it is also used in fields that require high toughness such as tool storage boxes, power tool jackets, sporting goods, bearings, gears, office machine housings, automobile bumpers, etc. It can also be used for large molded products, equipment used in cold regions, textile films, and adhesives. Next, the present invention will be specifically explained using reference examples, examples, and comparative examples. In the following, "parts" and "%" are all "parts by weight" unless otherwise specified.
and "% by weight" shall be meant. Reference example 1 Ethylene-butene-1 copolymer (manufactured by Mitsui Petrochemical Industries, Ltd., Tafmer A-4085) 100 parts, 1,3
-bis(t-butylperoxy-isopropyl)
Benzene (manufactured by Kayaku Nouri Co., Ltd., Perkadox)
14-40) After mixing 0.1 part and 0.5 part of maleic anhydride in a Henschel mixer, screw diameter 50 mm.
The mixture was melt-polymerized at 230°C using a φ, fully intermeshing type twin-screw extruder and pelletized to obtain a maleic anhydride grafted ethylene-butene-1 copolymer (a). A portion of this pellet was pulverized, and unreacted maleic anhydride was extracted with acetone using a Soxhlet extractor. The copolymer from which unreacted substances were removed was dissolved in cyclohexane, and the acid value was measured by titration with a 1/10N alcoholic KOH solution.The acid value was 5.2, which was 0.45% maleic anhydride when converted to maleic anhydride. was found to be grafted. Reference example 2 Ethylene-butene-1 copolymer (Tafmer A
-4085) was dissolved in 400 g of toluene at 80°C with stirring, and then 5 g of maleic anhydride was added and dissolved. Next, after heating the contents to 110°C, a solution of 0.15 g of tertiary butyl peroxybenzoate (Perbutyl Z, manufactured by NOF Corporation)/20 g of toluene was added dropwise over 1 hour, and polymerization was carried out at 110°C for 10 hours. I went there. The obtained graft polymer solution was diluted with toluene to a concentration of 5%, and then added little by little to an equivalent amount or more of methanol at 45 to 55°C to precipitate the graft polymer (b), which was washed and dried. Acid value measurement revealed that 4.7% maleic anhydride was grafted. Reference Example 3 In Reference Example 2, graft polymerization was carried out in the same manner as in Reference Example 2, using 1 g of maleic anhydride and 4 g of butyl acrylate instead of 5 g of maleic anhydride. The acid value of the obtained butyl acrylate/maleic anhydride grafted ethylene-butene-1 copolymer (c) was found to be grafted with 0.95% maleic anhydride. Reference example 4 Ethylene-propylene copolymer (Tafmer P
-0280) 100 parts, 0.1 part of 1,3-bis(t-butylperoxy-isopropyl)benzene (Perkadox 14-40) and 2 parts of 3-methyl-4-cyclohexene-1,2-dicarboxylic anhydride. After mixing in a shell mixer, the mixture was melt-polymerized in a twin-screw extruder at 230°C and pelletized to obtain a graft copolymer (d). Example 1 75 parts of polybutylene terephthalate (PBT) with intrinsic viscosity [η] 1.0, maleic anhydride grafted ethylene-butene-1 copolymer obtained in Reference Example 1
(a) 25 parts, Epiclon 3050 (manufactured by Dainippon Ink & Chemicals Co., Ltd., bisphenol A type diepoxy compound)
2 parts and 0.2 parts of Irganox 1010 (manufactured by Ciba Geigy, antioxidant) were uniformly mixed in advance, and this mixture was kneaded at 240°C in a 40 mmφ single screw extruder equipped with a Dalmage type screw and cooled. PBT resin composition pellets were obtained. Next, using an injection molding machine, a test piece for measuring physical properties is molded from this pellet, and the notched Izot guard strength (test piece thickness: 3mm),
Bending strength and bending modulus were measured according to ASTM D-790. Melt viscosity stability is the discharge amount (g/10 minutes) when the composition is maintained at 275°C in a melt indexer for a specified time (6 minutes and 30 minutes) and then discharged under a load of 3800 g, that is, the MI value. was measured and evaluated. The melt viscosity stability is judged to be better when the change in MI value after 30 minutes of holding is smaller than the MI value after 6 minutes of holding. The results are summarized in Table 1. Comparative Example 1 A composition was prepared in the same manner as in Example 1 except that the diepoxy compound was excluded, molded, and evaluated. Example 2 A composition was prepared, molded, and evaluated in the same manner as in Example 1, except that PBT was changed to 85 parts and graft copolymer (a) was changed to 15 parts. Example 3 In the composition of Example 1, the graft copolymer
A composition was prepared in the same manner except that (a) was changed to 20 parts and the diepoxy compound was changed to 6 parts, molded, and evaluated. Example 4 In the composition of Example 1, Epiclon N- was used instead of Epiclon 3050 as the epoxy compound.
A composition was prepared in the same manner except that 2 parts of 695 (manufactured by Dainippon Ink & Chemicals Co., Ltd., a cresol novolak type epoxy compound) was used, molded, and evaluated. Comparative Example 2 PBT alone used in Example 1 was molded and evaluated. Comparative Examples 3 and 4 In the composition of Example 1, the graft copolymer
A composition using polypropylene grafted with 6% acrylic acid instead of (a) (Comparative Example 3) and a composition using polyethylene grafted with 2% acrylic acid instead of graft copolymer (a) (Comparative Example 3) Example 4) was similarly prepared, molded and evaluated. Comparative Examples 5 and 6 In the composition of Example 1, the graft copolymer
Instead of (a), an ethylene-butene-1 copolymer (Comparative Example 5) and an ethylene-propylene copolymer (Comparative Example 6) before being grafted with an unsaturated carboxylic acid were used to obtain a composition by extrusion. Although molding was attempted, the compatibility was poor and normal melt-extruded strands could not be obtained, making it impossible to form pellets.

[Table] (Note) * Examples 5 to 7 Graft copolymer (a) with the composition of Example 1 without substantially breaking.
Instead of, the graft copolymer obtained in Reference Example 2
Composition using (b) (Example 5), composition using graft copolymer (c) obtained in Reference Example 3 (Example 6), and graft copolymer obtained in Reference Example 4 (d)
A composition using the composition (Example 7) was similarly prepared, molded, and evaluated. The results are shown in Table 2.

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Claims (1)

[Scope of Claims] 1 (A) 95 to 50 parts by weight of thermoplastic polyester resin (excluding polyester mainly composed of ethylene terephthalate repeating units), (B) 0.01 to 10 parts by weight of unsaturated carboxylic acid or its anhydride
Ethylene grafted with weight% and carbon number 3
5 to 50 parts by weight of a copolymer with α-olefin of ~6 and (C) 0.1 to 10 parts by weight of a polyepoxy compound ((A) and (B)
(based on a total of 100 parts by weight) of the thermoplastic polyester resin composition.