JPH0726007B2 - Method for producing polyester resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermoplastic polyester resin composition which gives a molded article having good moldability and excellent appearance and excellent mechanical properties such as impact resistance. It relates to the manufacturing method of a product.

[Conventional technology]

Polyester resin has mechanical properties, electrical properties, heat resistance,
It has excellent chemical resistance and is used in many industrial products. However, polyester resins have drawbacks such as inferior impact resistance, particularly notched impact strength, and poor moldability, and many improvement methods have been proposed in the past. For example, ethylene disclosed in JP-A-60-40154
A method of blending an epoxy monomer graft product of an α-olefin copolymer, a glycidyl group-containing copolymer comprising an α-olefin and a glycidyl ester of an α, β-unsaturated acid described in JP-A-58-17148 and Method for blending both ethylene-α-olefin copolymers, JP-A-58-387
The method of blending an alicyclic carboxylic acid-modified olefin-based elastomer disclosed in Japanese Patent No. 47 is relatively excellent in improving impact resistance of a polyester resin. However, these methods do not provide any solution for improving the moldability of the polyester resin. That is, a resin such as polyethylene terephthalate, which has a low crystallization rate, has a non-uniform crystallinity between the surface and the inside of the molded product, resulting in poor appearance, mechanical properties, dimensional stability, and shape stability.
Further, since crystallization does not occur sufficiently, a product having good heat resistance cannot be obtained. Therefore, a method of blending a nucleating agent and a plasticizer has been proposed in order to improve a molded article of polyethylene terephthalate. For example, JP-A-58-217547 discloses polyethylene terephthalate, a sodium or potassium salt of a copolymer of olefin and acrylic acid or methacrylic acid as a nucleating agent together with an inorganic filler, and an aliphatic carboxylic acid and an alcohol as a plasticizer. A method of blending the ester of the above has been proposed. According to this method, although it is possible to obtain a composition having excellent moldability, the surface of the composition is rough because it contains an inorganic filler, and therefore it is not suitable for applications requiring an excellent appearance. Further, even if the nucleating agent and the plasticizer disclosed in this patent are directly applied to the composition of the above polyester and the modified olefin elastomer, only a composition having a low impact strength can be obtained. Due to the above reasons, a polyester resin composition which is excellent in the appearance and impact resistance of a molded product and has a good moldability has not yet been found.

Therefore, the present inventors have conducted extensive studies to obtain a thermoplastic composition having good surface properties of a molded article, excellent mechanical properties such as impact resistance, heat resistance, and the like, and known as a result. The inventors have found that it is effective to devise a kneading method of the polyester resin modifying component, and arrived at the present invention.

That is, the present invention relates to a thermoplastic polyester resin (a) 100
Polyolefin (b) containing at least one polar group selected from the group consisting of carboxyl group, epoxy group and derivatives thereof in the molecule is melt-kneaded in the range of 1 to 100 parts by weight, and then organic Acid metal salt (c)
The gist is a method for producing a polyester resin composition, which comprises melt-kneading in a range of 0.01 to 20 parts by weight.

[Thermoplastic polyester resin (a)]

The thermoplastic polyester resin used in the present invention for the purpose of explaining the present invention in more detail has polyethylene terephthalate as a main object, but a part of its terephthalic acid component or glycol component is replaced with another copolymerization component. Is also good. Examples of the copolymer component include diphthalic acid such as isophthalic acid, naphthalenedi-carboxylic acid, 4,4′-diphenoxyethanedicarboxylic acid, adipic acid, sebacic acid and cyclohexanedicarboxylic acid, and ethylene as the diol component. Examples thereof include glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and copolyglycol of polyethylene glycol and polypropylene glycol. Of course, two or more kinds of these polyesters may be mixed. A preferred polyester is polyethylene terephthalate or a crystalline thermoplastic polyester having 80 mol% or more of ethylene terephthalate repeating units.

[Polyolefin containing one or more polar groups selected from the group consisting of carboxyl group, epoxy group and derivatives thereof in the molecule (hereinafter also referred to as polar group-containing polyolefin (b)] The polar group-containing polyolefin used in the present invention is , A vinyl monomer having a carboxyl group or an anhydride thereof in the molecule, or a vinyl monomer having an epoxy group in the molecule is copolymerized in the presence of an olefin monomer, or an olefin polymer and the above vinyl monomer. Examples thereof include those obtained by a method of graft-polymerizing a polymer, a method of oxidizing a double bond existing in a polydiene such as polybutadiene and polyisoprene by a known method to introduce an epoxy group, and the like.

Here, as the carboxyl group-containing vinyl monomer, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, bicyclo [2,2,1] hept-2-ene-5, Unsaturated carboxylic acids such as 6-dicarboxylic acid, maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, bicyclo [2,2,1] hept-2-ene-5,6-dicarboxylic anhydride Examples of such unsaturated carboxylic acid anhydrides include maleic anhydride. Glycidyl acrylate, glycidyl methacrylate, glycidyl methacrylate, itaconic acid monoglycidyl ester, butene dicarboxylic acid diglycidyl ester, butene dicarboxylic acid monoglycidyl ester, as the vinyl monomer having an epoxy group in the water distribution.
2-methylallyl glycidyl ether, vinyl-glycidyl ether, 3,4-epoxybutene, 3,4-epoxy-
Examples thereof include 3-methyl-1-butene, vinylcyclohexene monoxide, and P-glycidyl styrene. Among them, glycidyl methacrylate can be preferably used.

The olefin monomers include ethylene, propylene, butene-1,4-methylpentene-1, and hexene.
1, α-olefins such as decene-1, and diolephins such as butadiene and isoprene.

Moreover, polar group-containing polyolefin (also referred to as modified polyolefin) by grafting the polar group-containing vinyl monomer
Examples of the olefin polymer used as a starting material in the case of, are, for example, homopolymers of olefins such as polyethylene, polypropylene, polybutene-1, polypentene-1 or ethylene-propylene copolymer, ethylene-butene-1 copolymer. Polymer, propylene-butene-1 copolymer, ethylene-vinyl acetate copolymer, propylene-vinyl acetate copolymer, ethylene-butadiene copolymer, ethylene-isoprene copolymer, ethylene-chloroprene copolymer, propylene -Butadiene copolymer, ethylene-propylene-butadiene copolymer and other copolymers with different olefins or diolephins can be mentioned, and the type of the copolymer is random copolymer, block copolymer , A graft copolymer or an alternating copolymer.

And, in particular, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-vinyl acetate copolymer, ethylene-propylene-butadiene copolymer, ethylene-propylene-chloroprene copolymer and the like are preferable. The polyolefin or olefin elastomer may be used as a mixture of two or more kinds. Needless to say, the olefin polymer having a polar group can be used by itself.

The content of polar vinyl monomer in 100 parts by weight of modified polyolefin depends on the monomer species, but is generally 0.01 to 20% by weight.
Is preferred, and 0.05 to 15% by weight is more preferred. When the content of the polar vinyl monomer is 0.01% by weight or less, the effect of improving the impact strength is low, and when it is 20% by weight or more, the impact strength after the addition of the nucleating agent is significantly reduced.

The addition amount of the polar group-containing modified polyolefin needs to be 1 to 100 parts by weight, more preferably 2 to 80 parts by weight, based on 100 parts by weight of the polyester resin.

If the amount added is less than 1 part by weight, the effect of improving impact resistance is poor.
When it is 0 parts by weight or more, mechanical properties tend to be deteriorated.

[Organic acid metal salt (c)]

The organic acid metal salt used in the present invention is added to accelerate the crystallization rate of the polyester. That is, the organic acid metal salt contributes to the formation of crystal nuclei.

Examples of the organic acid forming the organic acid metal salt used in the present invention include formic acid, acetic acid, stearic acid, montanic acid,
Examples thereof include oleic acid, linoleic acid, oxalic acid, phthalic acid, isophthalic acid, terephthalic acid, tartaric acid, salicylic acid, benzoic acid, carbonic acid, and the like. Among them, benzoic acid is preferable, and the metal forming a salt is sodium or potassium. , Calcium, magnesium, barium, and zinc. Further, the organic acid metal salts used in the present invention include sodium, potassium, calcium, zinc salts and the like of copolymers of olefin and acrylic acid or methacrylic acid. Of the two, the latter is preferred. Of course, these organic acid metal salts may be used as a mixture of two or more kinds. The amount of the organic acid metal salt compounded is 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the polyester resin.

If the amount is less than 0.01 part by weight, the effect of promoting the crystallization rate is small, and if it exceeds 20 parts by weight, the mechanical properties and heat resistance of the polyester are adversely affected.

[Other ingredients]

In the composition obtained in the present invention, in addition to the essential components (b) and (c), if necessary, a stabilizer such as a plasticizer, an antioxidant, an ultraviolet absorber, a lubricant, a flame retardant, and an antistatic agent. Various inorganic or organic compounds such as colorants, release agents, fillers such as glass fibers and talc can be blended.

The plasticizer is preferably an ester of an aliphatic alcohol and a carboxylic acid, specifically, adipic acid-di-
(2-Ethylhexyl) ester, adipic acid-di-n
-Butyl ester, poly- (butane 1,3-diol adipate), poly (hexane-1,6-diol adipate), poly- (butane-1,4-diol adipate),
Examples thereof include montanic acid ester, alkylsulfonic acid-P-phenyl ester, diethylene glycol-di-benzoate, neopentyl glycol-di-benzoate, pentaerythritol dibenzoate, thio-di-ethanol-di-benzoate and the like. Of course, these may be mixed and used. The compounding amount is usually 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the polyester resin.

[Manufacturing method]

In the present invention, it is necessary to sufficiently melt-knead the polyester resin (a) and the polar group-containing polyolefin (b) before adding the organic acid metal salt (c) as a nucleating agent.

That is, after the polyester resin and the polar group-containing polyolefin are sufficiently melt-kneaded, an organic acid metal salt is added and melt-kneaded.

Even if the three essential components are melt-kneaded together, the impact strength of the polyester resin is not improved even if the components (a) and (c) are melt-kneaded and then the component (b) is melt-kneaded.

The kneading in the method for producing the composition of the present invention can be performed by a known method. For example, kneading may be performed in an extruder, a kneader or a Banbury mixer. At this time, it is preferable to knead so that the average dispersed particle diameter of the polar group-containing modified polyolefin is 3 μm or less.

The composition obtained according to the present invention can be easily molded by a usual method such as injection molding or extrusion molding, and particularly, at the time of injection molding.
Even if a mold having a temperature of 0 ° C. or lower is used, a molded product having a good appearance and excellent mechanical properties can be obtained. The composition of the present invention can be used in various forms and for various applications, and is particularly suitable for fields requiring impact resistance, high rigidity, and high heat resistance, such as automobile exterior panel materials.

The effects of the present invention will be described in detail below with reference to examples.

Example 1 Ethylene-butene copolymer 100 having an ethylene content of 85 mol% and a melt index at 190 ° C. of 3.60 g / 10 min.
Parts by weight and 1 part by weight of maleic anhydride, 2,5-dimethyl-2,5
-Di (tertiary butyl peroxy) hexin-30.
After mixing 06 parts by weight, the mixture was fed to a 25 mmφ, L / D = 28 single-screw extruder and extruded at 250 ° C. to obtain a maleic anhydride-modified ethylene-butene copolymer (hereinafter abbreviated as modified EBR). .
The modified EBR was dissolved in xylene, reprecipitated with acetone, dried, and the amount of maleic anhydride grafted was measured by a titration method to find 0.45% by weight. Next, the intrinsic viscosity is 0.65dl
80 parts by weight of polyethylene terephthalate pellets / g and 20 parts by weight of the modified EBR pellets shown above were mixed, fed to an extruder, and melt-kneaded / repelleted at 250 ° C. (PET
/ Modified EBR pre-kneaded product) After drying this pellet in a vacuum dryer, the sodium salt of ethylene-methacrylic acid copolymer with a neutralization degree of 60% as a nucleating agent (weight ratio of ethylene / methacrylic acid = 85/15 ) 3 parts by weight and 4 parts by weight of diethylene glycol dibenzoate as a plasticizer were added, and a pellet obtained by extruding again at 250 ° C with an extruder was injection-molded under the conditions of a cylinder temperature of 260 ° C and a mold temperature of 120 ° C.

Subsequently, physical properties were measured by the following methods.

MFR: Measured according to ASTM D-1238.

Flexural Modulus (FM) and Flexural Strength (FS): Measured by ASTM D790-80 using a 1/8 ″ thick test piece.

Izod impact strength (IZ): Measured by ASTM D-256 using a notched test piece having a thickness of 1/8 ".

Drop bar test (FD): A 2 mm thick test piece was annealed at 160 ° C. for 1 hour and then measured at −30 ° C. according to ASTM D-1709.

Heat distortion temperature (HDT): Measured by ASTM D-256 under the condition of a load of 66 PSI.

Crystallization rate (ΔH _H / ΔH _C : measured using a differential thermal analyzer (DSC). Samples were placed in a 1 mm thick mold at 290 ° C, 60 ° C.
The sheet was pressed under the condition of kg / cm ² and then cooled with water to obtain a pressed sheet. A sample of about 10 mg was weighed from the center of this press sheet, heated at 10 ° C / min and held at 290 ° C for 10 min, then 10 ° C.
DSC measurement was performed under the condition that the temperature was lowered at / min. From the obtained heat quantity curve, the heat quantity ΔH _H obtained from the peak area at the crystallization temperature at the time of temperature rise and the heat quantity ΔH _C obtained from the peak area at the crystallization at the time of temperature decrease were measured. The ΔH _H / ΔH _C thus obtained is an index of the easiness of crystallization, and the smaller this value is, the easier the crystallization of the polyester is.

Example 2 The modified EBR used in Example 1 was treated with an ethylene-glycidyl methacrylate copolymer (glycidyl methacrylate content).
10% by weight) and a 1: 1 mixture (weight ratio) of unmodified EBR are all used, and the results obtained by the same method as in Example 1 are shown in the table.

Comparative Example 1 80 parts by weight of polyethylene terephthalate used in Example 1 and 20 parts by weight of modified EBR, ethylene used in Example 1
3 parts by weight of sodium salt of methacrylic acid copolymer and 4 parts by weight of diethylene glycol dibenzoate were collectively supplied to the extruder and melt-kneaded / repelleted at 250 ° C. Then, injection molding was carried out using this pellet to measure the physical properties.
The results are shown in the table.

Comparative Example 2 The procedure of Comparative Example 1 was repeated except that the modified EBR of Comparative Example 1 was replaced with an ethylene-glycidyl methacrylate copolymer (glycidyl methacrylate content 10% by weight).

Comparative Example 3 The PET / modified EBR pre-kneaded product of Example 1 was injection molded and its physical properties were measured. The results are shown in the table.

Comparative Examples 4 and 5 As Comparative Example 4, the results of injection molding of polyethylene terephthalate alone were used. As Comparative Example 5, 80 parts by weight of polyethylene terephthalate was added to 3 parts by weight of the sodium salt of the ethylene-methacrylic acid copolymer used in Example 1, The results of injection molding of a sample containing 4 parts by weight of diethylene glycol dibenzoate are shown in the table.

Claims (1)

[Claims] 1. A polyolefin (b) containing, in 100 parts by weight of a thermoplastic polyester resin (a), at least one polar group selected from the group consisting of a carboxyl group, an epoxy group and derivatives thereof. Melt kneading in the range of 1 to 100 parts by weight, and then add the organic acid metal salt (c) to 0.2.
A process for producing a polyester resin composition, which comprises melt-kneading within the range of 01 to 20 parts by weight.