JPH0258560A - Molded article of polyethylene terephthalate for automobile part - Google Patents

Abstract

PURPOSE:To obtain the subject molded article having good surface appearance and high toughness and weld strength and useful for automobile parts by compounding a specific ethylenic copolymer containing glycidyl group with an olefinic copolymer and an organic carboxylic acid metal salt. CONSTITUTION:The objective molded article can be produced by the injection molding of a resin composition containing a matrix resin comprising a polyethylene terephthalate resin composed of (A) 100 pts.wt. of polyethylene terephthalate, (B) 3-50 pts.wt. of an ethylenic copolymer containing glycidyl group, (C) 0-80 pts.wt. of an olefinic copolymer composed of ethylene and >=3C alpha-olefin, (D) 0.01-5 pts.wt. of a 6-40C organic carboxylic acid metal salt and (E) 0-50 pts.wt. of a filler. The diameter of the particles of the components B and C dispersed in the matrix resin is essentially 0.01-10mum where in the content of the fraction having particle diameter of 0.1-2mum is 5-60% and the fraction of 3.5-6mum in diameter is 5-50%.

Description

[Detailed description of the invention] [Industrial application field] The present invention has a good surface appearance and high toughness,
First, it relates to polyethylene terephthalate molded products for automobile parts that have good bend strength.

[Conventional technology]

Various parts of automobiles require mechanical strength and toughness, so metal materials such as iron, zinc, and aluminum have traditionally been used.

In recent years, as the demands for weight reduction and design of automobiles have become more sophisticated, various plastic materials have been developed for automobile parts and are being used in place of metals.

When applying plastic to such auto parts,
In addition to mechanical strength and toughness, it also has good chemical resistance, no dimensional change due to moisture absorption, high surface hardness, heat resistance, and good surface appearance of molded products. In addition to requiring various properties, being able to supply it industrially at low cost is also an important economic factor. Polyethylene terephthalate (PET), which is used in large quantities as fibers and films, is a material that satisfies these various demands, but PET has the disadvantage of being extremely brittle unless stretched and oriented. A typical method to improve the brittleness of PET is to
Impact modifier (usually rubber component) in matrix resin
For example, there is a method of polymer alloying in which a random copolymer having a particle size of 0.01 to 3 μm is contained as an impact modifier in polyester such as PET (Japanese Patent Application Laid-Open No. 144452/1983). Public bulletin)
, a method of blending a copolymer consisting of an α-olefin, an α,β-unsaturated M glycidyl ester, and other heptamers with a polyester (Japanese Unexamined Patent Publications No. 5232045, No. 117049/1983); In addition, a method for improving impact resistance at low temperatures by blending polyester with a copolymer consisting of an α-olefin and a glycidyl ester of an α,β-unsaturated acid and an ethylene copolymer (Japanese Patent Laid-Open No. 5817148) Publications, Japanese Unexamined Patent Publication No. 17151/1983), etc.

[Problem to be solved by the invention]

Although it is true that the above method relatively improves impact resistance in the conventional sense, PUT to which such polymer alloy technology is applied has low strength at the weld part and also has a poor appearance. In reality, it has been difficult to use it as an automobile part.

[Means to solve the problem]

Therefore, the present inventors conducted intensive studies on means for improving the strength and appearance of the weld portion of a polyethylene terephthalate resin molded product, and as a result, they arrived at the present invention.

That is, the present invention includes (A) 100 parts by weight of polyethylene terephthalate (8)
3 to 50 parts by weight of an ethylene copolymer containing a glycidyl group (C) 0 to 80 parts by weight of an olefin copolymer consisting of ethylene and an α-olefin having 3 or more carbon atoms (D) Organic carbon having 6 to 40 carbon atoms Acid metal salt 0.01
5 parts by weight of the filler (E) and 0 to 50 parts by weight of the filler (E) A molded article formed by injection molding a resin composition having a matrix resin of polyethylene terephthalate, the matrix of the components (B) and (C) described above. The particle diameter dispersed in the resin is substantially in the range of 0.01 to 10 μI, of which the distribution ratio of particles with a particle diameter of 0.1 to 2 μm is 5 to 60%, and the particles are 3.5 to 6 μm. The present invention provides a polyethylene terephthalate molded article for automobile parts, characterized in that the distribution ratio of the diameter is 5 to 50%.

(8) Polyethylene terephthalate used in the present invention is a polymer obtained by condensation polymerization of terephthalic acid or its ester-forming derivative and ethylene glycol or its ester-forming derivative, and its terephthalic acid component or ethylene glycol component It is also possible to use one in which part of is replaced with a small amount of a copolymer component. These copolymerization components include isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 185-naphthalenedicarboxylic acid, bis(
p-carboxyphenyl)methane, anthracene dicarboxylic acid, 4.4' diphenyl ether dicarboxylic acid, 5
- Aromatic dicarboxylic acids such as sodium sulfoisophthalic acid, aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, and dodecanedioic acid, and alicyclic acids such as 1,3-cyclohexanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid. Dicarboxylic acid components such as dicarboxylic acids and their ester-forming derivatives, propylene glycol, 1,4-butanediol, neobentyl glycol, l,5-bentanediol, 1,6-hexanediol, decamethylene glycol, cyclohexane Examples include diol components such as dimetatool, cyclohexane diol, etc., or long chain glycols with molecules of 1,400 to 6,000, i.e., polyethylene glycol, poly-1,3-propylene glycol, polytetramethylene glycol, etc., and ester-forming derivatives thereof. It will be done.

Moreover, these polyethylene terephthalates are 0.5
% O-chlorophenol solution measured at 25°C has an intrinsic viscosity of 0.36 to 1.60, especially 0.52 to 1
．． A range of 35 is preferred. The viscosity is 0.
If the intrinsic viscosity is less than 36, the mechanical properties will be poor, and if the intrinsic viscosity exceeds 1.60, the moldability will be poor, both of which are unfavorable.

Furthermore, the amount of carboxy terminal groups of polyethylene terephthalate used in the present invention is 5 to 100 equivalents/10'
g. Polyethylene terephthalate polymer, especially 10~
60 wins! /106 g.Polyethylene terephthalate is preferred. The amount of the terminal group is 100 equivalents/10'
If it exceeds g. polyethylene terephthalate polymer, the dispersed particle size of the rubber components ((B) and (C)) tends to deviate from the predetermined particle size range of the present invention, and the effect of improving weld strength is undesirable. 5 equivalents/10'g・
If it is less than polyethylene terephthalate polymer, the effect of improving impact resistance will be small, which is not preferable.

The terminal carboxyl group amount of polyethylene terephthalate is, for example, Anal, Chem, 26.1614
-1616 (1954)) 1. A,
It can be measured using Pohl's method.

In addition, the melt viscosity of polyethylene terephthalate is 280
600 to 10 at 'C, sliding speed 100 sec-'
0.000 boise, preferably 1,000 to 50.00
0 voices, more preferably 1,500 to 30.00
It is in the range of 0 voice.

If the melt viscosity is too small or too large,
The dispersed particle size of the impact modifier tends to deviate from the specific particle size range of the present invention, resulting in poor weld strength improvement effect and poor surface appearance, which is undesirable.

The glycidyl group-containing ethylene copolymer (B) used in the present invention is a copolymer mainly composed of ethylene and glycidyl ester of α, β-unsaturated acid, and α
, a glycidyl ester of a β-unsaturated acid is a compound represented by the general formula (wherein R is a hydrogen atom, a lower alkyl group, or a lower alkyl group substituted with a glycidyl ester group), and the specific Examples include glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, and glycidyl itaconate, among which glycidyl methacrylate is preferably used. The copolymerized amount of glycidyl ester of α,β-unsaturated acid in the glycidyl group-containing copolymer is suitably in the range of 1 to 50% by weight, particularly 2 to 30% by weight. In addition, if the amount is 40% by weight or less, unsaturated monomers copolymerizable with the above copolymer, such as vinyl ethers, vinyl esters such as vinyl acetate and vinyl propionate, methyl, ethyl, propyl, butyl, hexyl, etc. One or more types of acrylic acid and methacrylic esters, acrylonitrile, styrene, carbon oxide, etc. may be copolymerized.

Preferred examples of the glycidyl group-containing ethylene copolymer (B) in the present invention include ethylene/glycidyl methacrylate copolymer, ethylene/vinyl acetate/glycidyl methacrylate copolymer, and ethylene/carbon oxide/glycidyl methacrylate copolymer. Examples include copolymers, ethylene/glycidyl acrylate copolymers, ethylene/glycidyl acrylate/vinyl acetate copolymers, and ethylene/glycidyl methacrylate/butyl acrylate copolymers.

The amount of the glycidyl group-containing copolymer (B) added in the present invention is 3 to 50 parts by weight, preferably 5 to 40 parts by weight, per 100 parts by weight of polyethylene terephthalate. If the amount added is less than 3 parts by weight, the impact resistance will be poor;
If the amount exceeds 0 parts by weight, the appearance of the molded product tends to be impaired, so it is not preferable.

(C) Ethylene and α- having 3 or more carbon atoms used in the present invention
The α-olefin having 3 or more carbon atoms in the olefin copolymer composed of olefins is preferably propylene, butene-1, pentene-1,3-methylpentene-1
, octacene-1, etc., and propylene and butene-1 are more preferred, and two or more of these can be used in combination. Further, in the olefin copolymer, a non-conjugated diene may be further copolymerized.

These non-conjugated dienes include preferably 5-methylidene-2-norbornene, 5-ethylidene-2-norbornene, dicyclopentadiene, 1,4-hexadiene, and the like. When non-conjugated diene is not included, the copolymerization ratio of ethylene and α-olefin having 3 or more carbon atoms is 5/9.
5-99/1 (molar ratio), preferably 60/40-9
The ratio is 7/3, more preferably 70/30 to 9515 (molar ratio).

In the olefin copolymer containing a non-conjugated diene, the copolymerization amount of the α-olefin having 3 or more carbon atoms is 5 to 80 mol%, preferably 20 to 60 mol%, and the copolymerization amount of the non-conjugated diene is 0. .1 to 20 mol%, preferably 0.5
~10 mol%.

Specific examples of olefin copolymers include ethylene/propylene copolymer, ethylene/butene-1 copolymer, ethylene/propylene/dicyclopentadiene copolymer,
Preferable examples include ethylene/propylene 15-ethylidene-2-norbornene copolymer, and among them, ethylene/propylene copolymer and ethylene/butene-1 copolymer that do not contain a non-conjugated diene have good heat resistance and are more preferably used. can.

The amount of these (C) olefin copolymers made of ethylene and α-olefin having 3 or more carbon atoms is 0 to 80 parts by weight per 100 parts by weight of polyethylene terephthalate;
Preferably it is 0 to 40 parts by weight. If it exceeds 80 parts by weight, it is not preferable because it tends to impair the mechanical properties of polyethylene terephthalate.

(B) Glycidyl group-containing ethylene copolymer used in the present invention and (C) ethylene and α- having 3 or more carbon atoms
The olefin copolymer made of olefin acts as an impact modifier that improves the impact resistance of polyethylene terephthalate, and the total amount of these impact modifiers added is 3 parts by weight per 100 parts by weight of polyethylene terephthalate.
It is preferably 90 parts by weight, more preferably 10 to 70 parts by weight. If the total amount added exceeds 90 parts by weight, the heat resistance and appearance will be poor, which is not preferred.

These impact modifiers ((B) and (
The melt flow rate (hereinafter abbreviated as MFR) of C)) is
It is preferably in the range of 0.05 to 200, more preferably 0.1 to 100, even more preferably 0.5 to 5
It is in the range of 0. If the VFR is too small or too large, not only will the impact resistance improvement effect be small, but the dispersed particle size of the impact resistance modifier ((B) and (C)) will not be within the predetermined particle size range of the present invention. This is not preferable because the effect of improving weld strength is poor. Here, MFR is a value determined according to ASTM D1238 (measured at 190° C.), and the unit is 8710 minutes.

The dispersed particle size of these impact modifiers of the present invention in polyethylene terephthalate is substantially in the range of 0.1 to 10 μm, and among these particles, the distribution ratio of particles with a particle size of 0.1 to 2 μm is 5 to 60 μm. %, preferably 10 to 50% and a distribution ratio of 3.5 to 6 μm.
-50%, preferably 5-40%. Impact modifier particle size 0.1-2 μm and 3.5
Each distribution rate of ~6 μm is less than 5%, and 60 and 50%
If it exceeds, the effect of improving weld strength will be insufficient,
Further, the appearance of the molded product tends to be poor, which is not preferable.

It is important that these two impact modifiers having particle sizes in specific ranges are present simultaneously in the polyethylene terephthalate matrix, and their simultaneous presence provides high weld strength and excellent impact resistance.

The distribution rate here refers to the section cut out from the molded product.
Observe this section under a microscope and measure the particle size of the impact modifier particles present in the visual field to create a particle size distribution map (Figure 1). Next, from the particle size distribution map, use the following formula ( This is the value calculated by 1).

Distribution rate (χ) of impact resistance modifier in specific particle size range...
(1) Specifically, the (D) organic carboxylic acid metal salt having 6 to 40 carbon atoms used in the present invention is an aliphatic monomer such as lauric acid, stearic acid, behenic acid, and montanic acid. Carboxylic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid,
Aliphatic dicarboxylic acids such as octadecanedicarboxylic acid and dimer acid, benzoic acid, P-chlorobenzoic acid, m-chlorobenzoic acid, 0-chlorobenzoic acid, p-methylbenzoic acid, p-tert-butylbenzoic acid, α- Naphthoic acid, β-naphthoic acid, 2-biphenylcarboxylic acid, 3-biphenylcarboxylic acid, 4-biphenylcarboxylic acid, 2-
Aromatic monocarboxylic acids such as biphenylsulfonecarboxylic acid and 2-diphenylmethanecarboxylic acid, alicyclic monocarboxylic acids such as cyclohexanecarboxylic acid, decahydro-α-naphthoic acid, and decahydro-β-naphthoic acid, terephthalic acid, isophthalic acid, Phthalic acid, 4.4'-'biphenyldicarboxylic acid, 3.3'-biphenyldicarboxylic acid, 1.1'-biphenyldicarboxylic acid, 4.4'-
diphenylmethane dicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, 4,4'-diphenylsulfone dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 1
, 4-naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid, anthracene dicarboxylic acid, aromatic dicarboxylic acids such as pyridine dicarboxylic acid, trimellitic acid,
It is a salt of acid components such as aromatic tricarboxylic acids such as trimesic acid and alkali metals such as lithium, sodium, potassium, and cesium, and alkaline earth metals such as calcium and barium, and the acids include stearic acid, montanic acid, and dodecadionic acid. , benzoic acid, terephthalic acid, isophthalic acid, monomethyl terephthalate, monomethyl isophthalate, and as metals, sodium, potassium, and barium are preferably used. These organic carboxylic acid metal salts are used as crystallization nucleating agents, and preferred specific examples thereof include potassium stearate, sodium stearate, barium stearate, sodium montanate, barium montanate, potassium benzoate, and sodium benzoate. ,
Examples include tere or sodium isophthalate, tere or sodium isophthalate 7-methyl ester, and the like.

The amount of these organic carboxylic acid metal salts added is preferably 0.01 to 5 parts by weight, preferably 0.1 to 2 parts by weight, based on polyethylene terephthalate.

If the amount added is less than 0.01 part by weight, the crystallization rate of polyethylene terephthalate will be slow and a good molded product will not be obtained. Moreover, if it exceeds 5 parts by weight, mechanical properties deteriorate, which is not preferable.

The molded product of the present invention also contains polyalkylene glycol derivatives such as polyethylene glycol, polyethylene glycol dibenzoate, polyethylene glycol bis(2-ethylenehexanoate), and benzoic acid esters such as neopentyl glycol dibenzoate as crystallization promoters. , polylactones, N-substituted toluenesulfonamide, etc. can be added in combination with a crystallization nucleating agent. By using a crystallization nucleating agent and a crystallization promoter together, better molded products can be obtained.

The filler (E) used in the present invention is fibrous, plate-like,
Fillers such as granules can be used, and specific examples include glass fibers, carbon fibers, mineral fibers, metal fibers, asbestos fibers, organic fibers, gypsum whiskers, potassium titanate whiskers, silicon carbide whiskers, alumina whiskers, graphite whiskers, silicate, lucium, wollastenite,
Calcium phosphate, calcium sulfate, calcium carbonate,
Metal oxides such as magnesium carbonate, barium sulfate, titanium oxide, zinc oxide, silicon oxide, iron oxide, zirconium oxide, antimony trioxide, molybdenum dioxide, mica, sericite, talc, kaolin, clay, feldspar, frogstone, glass Examples include organic powders such as powder, graphite, carbon black, and resin powder, and gypsum whiskers, potassium titanate whiskers, calcium silicate, wollastenite, calcium carbonate, magnesium carbonate, titanium oxide, mica, talc, and clay are particularly preferably used. can. Two or more of these fillers may be used as a mixture.

The amount of these fillers added is 0 to 50 parts by weight, preferably 0 to 30 parts by weight, based on the polyethylene terephthalate. If the amount added exceeds 50 parts by weight, the impact resistance of polyethylene terephthalate tends to decrease, which is not preferable.

Although the method for manufacturing the molded article of the present invention is not particularly limited, the dispersed particle size of the rubber component is greatly influenced by the amount of end groups of polyethylene terephthalate, melt viscosity, MFR of the impact modifier, and melt cross-talk conditions. Therefore, it can be manufactured by sufficiently controlling the above factors. for example,
Blended with polyethylene terephthalate and an ethylene copolymer containing a glycidyl group, an olefin copolymer consisting of ethylene and an α-olefin having 3 or more carbon atoms, an organic carboxylic acid metal salt, a filler, and/or other additives if necessary. ,2
The mixture is fed into an extruder equipped with a screw shaft and melted and kneaded to form pellets. At this time, the amount of end groups of polyethylene terephthalate, melt viscosity, MFR of the impact modifier, and degree of melt kneading are controlled to prevent the impact modifier from being finely dispersed too uniformly, and the pellets are then injected. Examples include a method in which a molded product having a desired shape is obtained by subjecting the product to a molding machine and performing injection molding using a mold set at a mold temperature of 70 to 150°C.

【Example〕

Hereinafter, the effects of the present invention will be further explained with reference to Examples.

In addition, parts in the examples mean parts by weight, and abbreviations mean the following.

E/GM^: Ethylene/glycidyl methacrylate (9
0/10 weight ratio) copolymer.

[! /VAC/GMA: ethylene/vinyl acetate/glycidyl methacrylate (90/3/7 weight ratio) copolymer.

E/BT: Ethylene/butene-1 (85/15 molar ratio) copolymer.

E/P: Ethylene/propylene (70/30 molar ratio) copolymer.

E/P/CPD: ethylene/propylene/dicyclopentadiene (70/28/2 molar ratio) copolymer.

E/P・8: Ethylene/propylene (20/80) block copolymer.

BSL Barium Nystearate.

SOB: Sodium benzoate.

STP8=sodium hephthalate.

PET: Polyethylene terephthalate.

Examples 1 to 12, Comparative Examples 1 to 6 Intrinsic viscosity is 0.75, carboxy terminal group amount is 32 equivalents! /
10'g polyethylene terephthalate polymer, 28
Rubber components having various MFRs shown in Table 1, barium stearate and ethylene bisstearylamide (EBA) shown in Table 1 were added to 100 parts by weight of polyethylene terephthalate having a melt viscosity of 6,300 voids at 0"C. The mixture was then blended using an extruder with a 30 fflff Iφ twin-screw screw, and the shear force during kneading was varied by changing the shape and rotation speed of the screw, and the mixture was heated at 290°C. ~300
The pellets were melt-kneaded at a resin temperature of ゛C to form pellets with different dispersion states of the impact modifier.

The obtained pellet and the maximum mold clamping pressure set at 280"C
Using a 5 ton screw in-line injection molding machine,
l/2" wide Izot impact test piece, 1/8"XI/2
"X5' welded molded product and 80mmX80
A square plate molded product with a width of 3 mm (thickness) was created. These test pieces were subjected to the following tests to evaluate their performance. The evaluation results are shown in Table 1.

Further, the shearing force during the above-mentioned kneading was expressed as the load current of the drive motor. The higher the load current, the greater the shearing force.

Performance Test Impact Resistance: ASTM D256 using 1/2" wide Izot impact test specimens at 23°C and -30°C.
One notched Izot impact test was conducted in accordance with .

Weld strength: A 1/8" x 1/2" x 2.5" impact test piece was cut out from a 1/8" x 1/2" x 5# welded molded product with the weld part at the center. An impact test was conducted to measure weld strength.

Particle size distribution (distribution rate) of impact modifier: 80a+X
A section was cut out from a 80 mm x 3 M test piece, and the dispersion state of the impact modifier was photographed under an electron microscope.
The photo is processed using an image analyzer (Image Analyzing Computer Quantaimet 720 manufactured by Keshi Bridge Instruments) to determine the particle size distribution of the impact modifier, and from this the distribution ratio of a specific particle size range is determined. Ta.

Appearance: The appearance of the 80mm x 80++us x 3mm test piece was visually observed.

○: Good ×: Poor (margin below next summer) As is clear from Table 1, the distribution of dispersed particle size varies depending on the MFR of the impact modifier and the degree of melt-kneading, and impact resistance improvement is within the scope of the present invention. The molded articles of Examples having the agent particles have superior weld strength and appearance compared to the molded articles of Comparative Examples.

Examples 13 and 14, Comparative Examples 7 to 9 The performance was evaluated in the same manner as in Example 3, except that polyethylene terephthalate with various melt viscosities was used.

The results are shown in Table 2.

(Leaving space below) As is clear from Table 2, the dispersed particle size of the impact modifier varies depending on the melt viscosity of polyethylene terephthalate, and the molded products of Examples having impact modifier particles are within the scope of the present invention. The molded product has superior weld strength and appearance compared to the comparative molded product.

Examples 15-20, Comparative Examples 9-15 The composition of Example 3 was further added with 15 fillers shown in Table 3.
The performance was evaluated in the same manner as in Example 3 except that part by weight was added.

The results are shown in Table 3.

(Leaving space below) Table 3 shows that the molded articles of Examples in which the particle size distribution of the impact modifier falls within the range of the present invention are superior in weld strength and appearance compared to Comparative Examples.

〔Effect of the invention〕

The molded product of the present invention has high toughness, weld strength, and good appearance, and is industrially useful as a molded product for automobile parts.

[Brief explanation of the drawing]

FIG. 1 is a particle size distribution diagram for determining the particle size distribution ratio in the present invention. X: Area of specific particle size range Y: Area of entire particle size range

Claims (1)

[Claims] (A) 100 parts by weight of polyethylene terephthalate (B)
3 to 50 parts by weight of an ethylene copolymer containing a glycidyl group (C) 0 to 80 parts by weight of an olefin copolymer consisting of ethylene and an α-olefin having 3 or more carbon atoms (D) Organic carbon having 6 to 40 carbon atoms Acid metal salt 0.01
5 parts by weight of the filler (E) and 0 to 50 parts by weight of the filler (E) A molded article formed by injection molding a resin composition having a matrix resin of polyethylene terephthalate, the matrix of the components (B) and (C) described above. The particle size dispersed in the resin is substantially in the range of 0.01 to 10 μm, of which the distribution ratio of particles having a particle size of 0.1 to 2 μm is 5 to 60%, and the particles are 3.5 to 6 μm. A polyethylene terephthalate molded article for automobile parts, characterized in that the distribution ratio of the diameter is 5 to 50%.