JP3312429B2 - Thermoplastic resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin composition, and particularly to a polybutylene terephthalate resin (hereinafter referred to as "polybutylene terephthalate resin").
Abbreviated as "PBT resin". ), A small amount of a graft copolymer (hereinafter abbreviated as “AES resin”) obtained by graft copolymerizing styrene and acrylonitrile with an ethylene / propylene / non-conjugated diene copolymer rubber. The present invention relates to a thermoplastic resin composition having significantly improved impact resistance and an excellent balance of mechanical properties such as rigidity.

[0002]

2. Description of the Related Art PBT resin is widely used as an engineering plastic, but has a notch.
There is a drawback that the impact strength is small when a mark is added, and many studies have been made in the past for this improvement.

[0003] For example, a method of blending a graft copolymer based on a conjugated diolefin having a specific composition with a PBT resin (Japanese Patent Publication No. 51-25261 or the like), or a method using a specific PBT resin with an acrylic rubber as a base. A method of blending a graft copolymer (Japanese Patent Publication No. 24414/1990),
Furthermore, a method of blending a graft copolymer based on ethylene / propylene / non-conjugated diene rubber with a PBT resin (Japanese Patent Application Laid-Open No. 60-51740, Japanese Patent Publication No. 63-61971)
No. 1-36857).

[0004]

The above-mentioned conventional composition comprises:
Although the impact strength of the PBT resin is greatly improved, particularly in order to obtain a material having a high impact strength, a large amount of the graft copolymer is required.
If the amount is less than 0 parts by weight, the effect is often small. In particular, if the amount is less than 30 parts by weight, the effect is small.
However, blending a large amount of the graft copolymer impairs the inherent properties of the PBT resin and is not preferable.

[0005] The present invention solves the above-mentioned conventional problems and provides a PB
An object of the present invention is to provide a thermoplastic resin composition capable of obtaining high impact strength by blending a small amount of a graft copolymer with a T resin.

[0006]

The thermoplastic resin composition according to claim 1 is a thermoplastic resin composition comprising 5 to 40 parts by weight of a graft copolymer and 95 to 60 parts by weight of a polybutylene terephthalate resin. The graft copolymer is an ethylene / propylene / non-conjugated diene copolymer 10
50 to 80 parts by weight of an ethylene / propylene / non-conjugated diene copolymer-containing crosslinked latex in which 1 to 20 parts by weight of an acid-modified low molecular weight α-olefin copolymer is uniformly dispersed in 0 parts by weight of rubber latex particles A) a monomer mixture 50 to 20 containing 60 to 76% by weight of an aromatic vinyl monomer and 40 to 24% by weight of a vinyl cyanide monomer.
Parts by weight of the ethylene-propylene-non-conjugated diene copolymer-containing cross-links continuously for 1 hour or more in the emulsion graft polymerization in the presence of the redox-based initiator. It is a graft copolymer obtained by adding to latex.

A thermoplastic resin composition according to claim 2 is the thermoplastic resin composition according to claim 1, wherein the crosslinked latex containing ethylene / propylene / non-conjugated diene copolymer has a gel content of 40 to 90% by weight, It is characterized in that the particle diameter is 0.2 to 1 μ.

The thermoplastic resin composition according to claim 3 is the thermoplastic resin composition according to claim 1 or 2, wherein the redox initiator is cumene hydroperoxide, ferrous sulfate,
It is characterized by comprising sodium pyrophosphate and dextrose.

That is, the present inventors have conducted intensive studies to solve the above-mentioned conventional problems, and as a result, by blending the PBT resin with the AES graft copolymer obtained by a specific production method, The inventors have found that high impact strength can be obtained by adding a small amount of AES graft copolymer, and have completed the present invention.

Hereinafter, the present invention will be described in detail.

First, the graft copolymer of the present invention will be described. The ethylene / propylene / non-conjugated diene copolymer (hereinafter abbreviated as “EPDM”) as a rubber component in the graft copolymer according to the present invention is a rubbery copolymer of ethylene, propylene and a non-conjugated diene. However, the concentration of ethylene contained is 40-90 mol%
The diene component includes 1,4-hexadiene and 5-diene.
Those containing ethylidene-2-norbornene, 5-vinylnorbornene, dicyclopentadiene and the like are preferred.

Examples of the acid-modified low molecular weight α-olefin copolymer include an acid-modified polyethylene containing 99.8 to 80% by weight of an α-olefin and 0.2 to 20% by weight of an unsaturated carboxylic acid compound. Here, ethylene and the like as the α-olefin, and as the unsaturated carboxylic acid,
Acrylic acid, maleic acid, itaconic acid, maleic anhydride, itaconic anhydride, maleic acid monoamide and the like can be mentioned.

[0013] Such an acid-modified low molecular weight α-olefin copolymer is added to 100 parts by weight of the EPDM,
By adding 1 part by weight or more, the impact strength of the finally obtained thermoplastic resin composition can be increased. However, even if the compounding amount of the acid-modified low molecular weight α-olefin copolymer exceeds 20 parts by weight, the impact strength is not further improved. Therefore, in the present invention, the EPDM-containing crosslinked latex is based on 100 parts by weight of EPDM. It is assumed that 1 to 20 parts by weight of an acid-modified low molecular weight α-olefin copolymer is blended.

This EPDM-containing crosslinked latex has a gel content of 40 to 90% by weight and a particle diameter of 0.2 to 0.2%.
１1 μm is preferable in terms of balance of physical properties. When the gel content is less than 40% by weight, the impact resistance and surface appearance of the finally obtained thermoplastic resin composition deteriorate, and when the gel content is more than 90% by weight, the obtained thermoplastic resin composition has The impact resistance of the resin composition is significantly deteriorated. On the other hand, if the particle size is less than 0.2μ, the impact resistance of the obtained thermoplastic resin composition is significantly deteriorated, and if it exceeds 1μ, the gloss of the obtained thermoplastic resin composition is reduced and the impact strength is also reduced. descend.

The monomer to be graft-polymerized to the EPDM-containing crosslinked latex is a mixture of an aromatic vinyl monomer and a vinyl cyanide monomer. Among these monomers, aromatic vinyl monomers include styrene, α-methylstyrene, p-methylstyrene and the like. Examples of the vinyl cyanide monomer include acrylonitrile, methacrylonitrile and the like.

In the present invention, the monomer mixture contains 60 to 76% by weight of an aromatic vinyl monomer and 40 to 24% by weight of a vinyl cyanide monomer.

The graft copolymer according to the present invention comprises the above-mentioned E
50 to 80 parts by weight (as solid content) of an EPDM cross-linked latex containing 1 to 20 parts by weight of an acid-modified low molecular weight α-olefin copolymer per 100 parts by weight of PDM, and 50 to 20 parts by weight of the monomer mixture Part obtained by emulsion graft polymerization. EPDM in graft copolymer
When the content of the cross-linked latex is less than 50 parts by weight and the content of the monomer mixture is more than 50 parts by weight, the impact strength of the final composition is not improved, and
If the amount is more than 20 parts by weight and the amount of the monomer mixture is less than 20 parts by weight, the impact strength, rigidity and surface appearance of the final composition are deteriorated.

The graft copolymer according to the present invention is preferably produced, for example, as follows. That is, first, an EPDM-containing crosslinked latex in which an acid-modified low molecular weight α-olefin copolymer is uniformly dispersed in EPDM is produced. For example, a predetermined amount of EPDM and an acid-modified low molecular weight α-olefin copolymer is dissolved in an appropriate solvent, and an emulsifier is added to this to emulsify. In this case, as the solvent, an aliphatic or aliphatic hydrocarbon solvent such as n-hexane and cyclohexane can be used. The emulsifier is not particularly limited. For example, an anionic surfactant such as potassium oleate or disproportionated potassium rosinate is used. The addition amount of the emulsifier is preferably 1 to 10 parts by weight based on EPDM. The emulsifier may be added, for example, by mixing oleic acid with EPDM and an acid-modified low-molecular-weight α-olefin copolymer solution, adding an aqueous potassium hydroxide solution thereto, and forming potassium oleate. Can also.

The compounding amount of the acid-modified low molecular weight α-olefin copolymer is 1 to 20 parts by weight with respect to EPDM.
By adding the acid-modified low molecular weight α-olefin copolymer at such a ratio, stable graft polymerization can be performed, and good impact strength can be given to the final resin composition.

After a solution of EPDM and an acid-modified low-molecular-weight α-olefin copolymer is emulsified with an emulsifier, the mixture is sufficiently stirred, and the solvent is distilled off to obtain a particle size of 0.2 to 0.2.
A latex of about 1 μ is obtained.

Next, this latex EPDM 10
0.1 to 5.0 parts by weight of a polyfunctional compound such as divinylbenzene and 0.1 to 5.0 parts by weight of an organic peroxide such as di-t-butyl-oxytrimethylcyclohexane with respect to 0 parts by weight.
5.0 parts by weight, and at 60 to 140 ° C., 0.5 to
The crosslinked latex is prepared by reacting for about 5.0 hours.

In the present invention, as described above, the gel content of the EPDM-containing crosslinked latex thus adjusted is preferably about 40 to 95% by weight. The gel content of the EPDM-containing crosslinked latex was determined by washing the latex with dilute sulfuric acid, drying it, collecting 1 g of the latex, immersing the latex in 200 ml of toluene at 100 ° C. for 5 hours, and then using a 200 mesh stainless steel mesh. It can be determined by filtering and drying the residue.

Next, the EPDM thus adjusted
Containing crosslinked latex 50-80 parts by weight (as solid content)
Then, 50 to 20 parts by weight of the monomer mixture is heated to an appropriate polymerization temperature to carry out graft polymerization.

In the present invention, it is necessary to mix a redox initiator with the monomer mixture and to continuously add it to the polymerization system over one hour. If the addition time is less than one hour, the impact strength of the final product will decrease. The addition time varies depending on the scale of the reaction system.
When adding about 2 parts by weight of the monomer mixture,
Preferably, the time is about 3 hours.

The redox initiator used here is preferably an organic peroxide, and is usually used in a combination of ferrous sulfate, a chelating agent and a reducing agent.
Oil-based initiators include cumene hydroperoxide, diisopropylbenzene hydroperoxide,
Organic peroxides such as tert-butyl hydroperoxide are preferred. The most preferred redox initiator is
It is composed of cumene hydroperoxide, ferrous sulfate, sodium pyrophosphate and dextrose.
Such a redox-based initiator is a monomer mixture 100
It is preferable to use about 0.5 to 5.0% by weight to the weight part.

After the completion of the polymerization, an antioxidant is added, if necessary, and then a resin solid content is precipitated from the obtained graft copolymer latex. In this case, as the precipitant, for example, an aqueous solution of sulfuric acid, acetic acid, calcium chloride, magnesium sulfate or the like can be used alone or in combination. Graft copolymer latex to which a precipitant is added,
After heating and stirring, the precipitate is separated, washed with water, dehydrated and dried to obtain a graft copolymer.

On the other hand, the PBT resin in the present invention is terephthalic acid or a dialkyl ester of terephthalic acid,
It is a polyester resin obtained by polycondensation with 1,4-butanediol. Part of the terephthalic acid constituting the PBT resin is a dibasic acid such as isophthalic acid, hexahydrophthalic acid, diphenylcarboxylic acid, adipic acid or azelaic acid or a polybasic acid such as trimesic acid or trimellitic acid. May be replaced by
-Butanediol is partially ethylene glycol,
Diols or glycerin such as diethylene glycol, cyclohexadimethanol, neopentyl glycol, bisphenol A, halogen-containing bisphenol A,
It may be replaced with a polyhydric alcohol such as pentaerythritol.

The thermoplastic resin composition of the present invention comprises 5 to 40 parts by weight of the above graft copolymer and 95 to 50 parts by weight of the PBT resin.
60 parts by weight, preferably a graft copolymer and PB
The total amount with the T resin is 100 parts by weight. When the amount of the graft copolymer in the thermoplastic resin composition of the present invention is less than 5 parts by weight and the amount of the polybutylene terephthalate resin is more than 95 parts by weight, the intended impact strength cannot be obtained, and the graft copolymer is 40 parts by weight. When the amount is more than 60 parts by weight and the amount of the polybutylene terephthalate resin is less than 60 parts by weight, the rigidity is deteriorated, and either case is not preferable.

[0029] Such a thermoplastic resin composition of the present invention comprises a predetermined amount of the graft copolymer and the PBT resin.
Easily manufactured by mixing with an antioxidant, a lubricant, a processing aid, a pigment, a filler, and the like as necessary, and kneading with an extruder, a Banbury mixer, a kneading roll, or the like to form a pellet. Can be.

[0030]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Production Examples, Examples, and Comparative Examples, but the present invention is not limited to the following Examples unless it exceeds the gist thereof. In the following, “parts” indicates “parts by weight”.

Production Example 1 Production of EPDM-Containing Crosslinked Latex EPDM (trade name: EPT301) manufactured by Mitsui Petrochemical Co., Ltd.
2P, ethylene content: 82 mol%) 100 parts of n-
After dissolving in 566 parts of hexane, modified polyethylene manufactured by Mitsui Petrochemical Co., Ltd. (trade name: High Wax 2203A)
Was added in the amounts shown in Table 1, and oleic acid was further added to dissolve completely. Separately, KOH 0.
An aqueous solution in which 9 parts were dissolved was kept at 60 ° C., and the above-prepared polymer solution was gradually added to emulsify the mixture, followed by stirring with a homomixer. Next, a part of the solvent and water were distilled off to obtain a latex having a particle size of 0.55 to 0.6 μm. To this latex was added 1.5 parts of divinylbenzene and 100 parts of di-t-butylperoxytrimethylcyclohexane with respect to 100 parts of EPDM as a rubber component, respectively, and reacted at 120 ° C. for 1 hour. EPDM-containing crosslinked latex no. 1-1 to 1-4 were prepared.

EPDM-containing crosslinked latex no. 1-
5, 1-6 added 0 parts and 30 parts of acid-modified polyethylene, 1-7, 1-8 added 0.2 parts of di-t-butylperoxytrimethylcyclohexane,
Except having added 3.0 parts, it manufactured similarly to the said method.

In addition, EPDM-containing crosslinked latex No.
1-9 and 1-10 are each 7.0 parts of oleic acid,
Except adding 2.0 parts, it manufactured like the above-mentioned method.

Each of the EPDM-containing crosslinked latexes was coagulated with dilute sulfuric acid, washed with water and dried.
g of each latex was collected, immersed in 200 ml of toluene at 100 ° C. for 5 hours, and then filtered through a 200-mesh stainless steel wire gauze, and the residue was dried to determine the gel content of each latex. was gotten.

Production of Graft Copolymer Nos. In Tables 2 and 3 were placed in a stainless steel polymerization tank equipped with a stirrer. 2-
Raw materials were charged according to the formulations shown in 1-2-17 and polymerization was carried out.
The polymerization temperature was constant at 80 ° C. The addition time of the component (II) was 150 minutes, and the addition time of the component (III) was 180 minutes.

After the polymerization, an antioxidant was added, and the solid content was precipitated with sulfuric acid. After washing, dehydration and drying, the graft copolymer powder No. 1 was obtained. 2-1 to 2-17 were obtained.

The graft copolymer No. 2-1 to 2
Tables 2 and 3 show the conversion of each monomer in the production of -17. The monomer conversion was calculated from the residual monomer obtained by collecting a part of the latex and using gas chromatography.

[0038]

[Table 1]

[0039]

[Table 2]

[0040]

[Table 3]

Examples 1 to 10 and Comparative Examples 1 to 12 The graft copolymer obtained in Production Example 1 and P (produced by Ube Industries, Ltd.)
A twin screw extruder (manufactured by Toyo Seiki Co., Ltd.) having the composition shown in Tables 4 and 5 together with BT resin (trade name: UBE 1000V-01) and 0.5 parts of polyethylene wax (trade name: Flowsen UF) manufactured by Nippon Steel Chemical Co., Ltd. Labo Plast Mill Model 15R
Kneading at 300) and molding at 260 ° C. The obtained resin composition No. Various characteristics of 3-1 to 3-22 were tested under the following conditions and methods, and the results are shown in Tables 4 and 5.

Notched Izod impact value: ASTM
Flexural modulus according to D256 Flexural modulus according to ASTM D790 HDT (thermal deformation temperature of molded product) (° C): 18.6 kg / c
m ² ASTM D648 Gloss: JIS Z8741 (incident angle 60 °
From Tables 4 and 5, it is clear that the thermoplastic resin composition of the present invention has a good balance of impact resistance, rigidity, and HDT, and has extremely excellent properties.

[0043]

[Table 4]

[0044]

[Table 5]

[0045]

As described above in detail, according to the thermoplastic resin composition of the present invention, the properties such as impact resistance and rigidity are extremely high, and the balance between these properties is excellent. A thermoplastic resin composition is provided.

Continuation of the front page (56) References JP-A-5-17677 (JP, A) JP-A-63-291913 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 67 / 00-67/02

Claims (3)

(57) [Claims] 1. A thermoplastic resin composition comprising 5 to 40 parts by weight of a graft copolymer and 95 to 60 parts by weight of a polybutylene terephthalate resin, wherein the graft copolymer is an ethylene / propylene / non-conjugated diene copolymer. 50 to 80 parts by weight of an ethylene / propylene / non-conjugated diene copolymer-containing crosslinked latex in which 1 to 20 parts by weight of an acid-modified low molecular weight α-olefin copolymer is uniformly dispersed in 100 parts by weight of rubber latex particles ), 50 to 20 parts by weight of a monomer mixture containing 60 to 76% by weight of an aromatic vinyl monomer and 40 to 24% by weight of a vinyl cyanide monomer, in the presence of a redox initiator, In the emulsion graft polymerization, the redox initiator and the monomer mixture are continuously added to the ethylene / propylene / non-conjugated diene for one hour or more. A thermoplastic resin composition, which is a graft copolymer obtained by adding to a copolymer-containing crosslinked latex. 2. The thermoplastic resin composition according to claim 1, wherein the crosslinked latex containing ethylene / propylene / non-conjugated diene copolymer has a gel content of 40 to 90% by weight,
A thermoplastic resin composition having a particle size of 0.2 to 1 μm. 3. The thermoplastic resin composition according to claim 1, wherein the redox initiator comprises cumene hydroperoxide, ferrous sulfate, sodium pyrophosphate and dextrose. object.