JP3136435B2 - Thermoplastic resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to fluidity, heat resistance,
The present invention relates to a thermoplastic resin composition having excellent mechanical properties.

[0002]

2. Description of the Related Art Polyphenylene ether resins have properties such as excellent mechanical properties, electrical properties, acid resistance, alkali resistance, heat resistance, etc., and low water absorption and good dimensional stability. It is widely used as a housing for OA equipment such as computers and word processors, as a material for chassis, and the like. In addition, these materials are often required to be flame-retardant due to the problem of fire.However, polyphenylene ether resins can be highly flame-retardant by adding a phosphorus compound without using a halogen compound. However, its use value is increasing from the viewpoint of safety. However, with the remarkable progress of recent OA equipment, the equipment has been advanced and downsized and lightened, and as a result, these materials are often formed in a thin wall, and further fluidity (moldability). Improvement is desired.

Since polyphenylene ether has poor fluidity, it is generally disclosed in JP-B-43-17812 and US Pat. No. 3,383,435.
Used as a mixture with polystyrene. Polyphenylene ether and polystyrene are completely compatible at an arbitrary ratio, and the fluidity increases in proportion to the polystyrene ratio, but the heat resistance decreases inversely. In addition,
Japanese Patent No. 40046 discloses a mixture of a styrene-acrylonitrile copolymer containing 3 to 18% by weight of a polyphenylene ether and an acrylonitrile component.
The balance among heat resistance, fluidity and mechanical properties was not always satisfactory.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a resin composition containing polyphenylene ether which is excellent in balance of fluidity, heat resistance, mechanical properties and the like, and is also excellent in flame retardancy. That is.

[0005]

Means for Solving the Problems In order to achieve the above object, the present inventors have made intensive studies on the improvement of fluidity and heat resistance of a polyphenylene ether-based resin composition, and as a result, (A) polyphenylene ether, (B) Polystyrene and / or rubber-modified polystyrene, and a melt flow rate containing 7 to 11% by weight of an acrylonitrile component (C) is 5-1.
A resin composition obtained by mixing a styrene-acrylonitrile copolymer with a specific ratio of 00 g / 10 minutes has fluidity,
The inventors have found that the heat resistance, mechanical properties, and the like are excellent in balance, and have reached the present invention.

That is, the present invention relates to (A) 30 to 95% by weight of polyphenylene ether, (B) 2 to 60% by weight of polystyrene and / or rubber-modified polystyrene,
(C) A resin composition comprising 3 to 40% by weight of a styrene-acrylonitrile copolymer containing 7 to 11% by weight of an acrylonitrile component, wherein the melt flow rate of the component (C) (at 220 ° C. under a load of 10 kg) Is 5 to 100 g
/ 10 minutes.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The component (A) polyphenylene ether of the present invention is a homopolymer or a copolymer having a repeating unit represented by the general formula (I) and / or (II).

[0008]

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[0009]

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(Where R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆
Independently represents an alkyl group having 1 to 4 carbon atoms, an aryl group, halogen, or hydrogen. However, R ₅ and R ₆ are not simultaneously hydrogen. )

A typical example of the homopolymer of the polyphenylene ether resin is poly (2,6-dimethyl-1,4-
Phenylene) ether, poly (2-methyl-6-ethyl-1,4-phenylene) ether, poly (2,6-diethyl-1,4-phenylene) ether, poly (2-ethyl-6-n-propyl-) 1,4-phenylene) ether, poly (2,6-di-n-propyl-1,4-phenylene) ether, poly (2-methyl-6-n-butyl-
1,4-phenylene) ether, poly (2-ethyl-6)
-Isopropyl-1,4-phenylene) ether, poly (2-methyl-6-chloroethyl-1,4-phenylene) ether, poly (2-methyl-6-hydroxyethyl-1,4-phenylene) ether, poly ( Homopolymers such as 2-methyl-6-chloroethyl-1,4-phenylene) ether are exemplified.

Among them, poly (2,6-dimethyl-1,1)
4-Phenylene) ether is particularly preferred.

Here, the polyphenylene ether copolymer is a copolymer having a phenylene ether structure as a main unit. Examples thereof include copolymers of 2,6-dimethylphenol and 2,3,6-trimethylphenol,
Copolymer of 2,6-dimethylphenol and o-cresol or 2,6-dimethylphenol and 2,3,6
-Copolymers with trimethylphenol and o-cresol.

The polystyrene of the component (B) is a homopolymer of styrene, and the rubber-modified polystyrene is a graft copolymer of a rubbery polymer and styrene. Further, as the rubber used for the rubber-modified polystyrene, polybutadiene, styrene-butadiene copolymer, polyisoprene,
Butadiene-isoprene copolymer, natural rubber, ethylene-propylene copolymer and the like can be mentioned. Particularly, polybutadiene and styrene-butadiene copolymer are preferable.

The styrene-acrylonitrile copolymer (C) used in the present invention has an acrylonitrile component of 7%.
-11% by weight, preferably 8-10% by weight, more preferably 8.5-9.5% by weight. Further, the composition distribution of the copolymer is more preferably narrow for the following reasons.

FIG. 1 shows the dynamic viscoelastic behavior of the component resin and the composition, and shows the relationship between the change in the loss modulus (E ″) and the temperature. As can be seen from FIG. 1, acrylonitrile is shown. A three-component melt mixture of the copolymer containing 7 to 11% by weight of a component, polyphenylene ether and polystyrene shows two glass transition points according to dynamic viscoelasticity measurement (Example 1), Observation of the morphology with an electron microscope confirms the phase separation structure, which has two glass transition points sufficiently higher than those of the styrene-acrylonitrile copolymer and polystyrene, and the glass transition point of polyphenylene ether. (AS-1 alone and PP
E-1 alone), it is presumed to have a phase structure separated into a phase composed of polystyrene and some polyphenylene ether, and a phase composed of the styrene-acrylonitrile copolymer and the remaining polyphenylene ether. Also, from the change in the two glass transition points when the mixing ratio of polystyrene and the styrene-acrylonitrile copolymer was changed (Comparative Example 1 and Comparative Example 2), the phase of polystyrene and a portion of polyphenylene ether was determined. Indicates a high glass transition point, and it is presumed that the phase composed of the styrene-acrylonitrile copolymer and the remaining polyphenylene ether exhibits a low glass transition point.

In the copolymer, when the content of the acrylonitrile component is less than 7% by weight, when mixed with polyphenylene ether and polystyrene, the viscoelastic behavior and fluidity and heat resistance are the same as those of the mixture of polyphenylene ether and polystyrene. It only shows the balance of When the content of the acrylonitrile component exceeds 11% by weight, the glass transition temperature is close to that of a styrene-acrylonitrile copolymer alone and the glass transition temperature of a mixture of polyphenylene ether and polystyrene because the compatibility is poor. Is easy to cause delamination, has no practical value, and has poor mechanical properties.

The styrene-acrylonitrile copolymer has a melt flow rate of 5 to 100 g / 10 minutes, a preferable range is 30 to 80 g / 10 minutes, and a more preferable range is 40 to 60 g / 10 minutes. The higher the melt flow rate of the styrene-acrylonitrile copolymer, the better the fluidity of the composition. However, if it exceeds 100 g / 10 minutes, the mechanical strength of the composition of the present invention is poor, which is not preferable.

The mixing ratio of each component constituting the composition of the present invention is as follows: (A) 30 to 95% by weight of polyphenylene ether;
The preferred range is 2 to 60% by weight of (B) polystyrene and / or rubber-modified polystyrene, and 3 to 40% by weight of the styrene-acrylonitrile copolymer of component (C). More preferably, the range is 40 to 80% by weight of the component (A), 3 to 50% by weight of the component (B), and 10 to 35% by weight of the component (C).

If the content of polyphenylene ether is less than 30% by weight, the heat resistance is low and the characteristics of the composition of the present invention are not exhibited.
60% by weight of polystyrene or rubber-modified polystyrene
In the case where the ratio exceeds 1, the characteristics of the composition of the present invention are similarly low due to low heat resistance. The styrene-acrylonitrile copolymer may be blended within a range to obtain a desired fluidity, but if it exceeds 40% by weight, the heat resistance is greatly reduced, which is not preferable. In the composition of the present invention, it is necessary that a phase composed of polystyrene and a part of polyphenylene ether forms a matrix, and it depends to some extent on the blending amount of polyphenylene ether and the acrylonitrile content of the styrene-acrylonitrile copolymer. However, if the blending amount of the styrene-acrylonitrile copolymer exceeds 40% by weight, it is considered that the phase composed of the styrene-acrylonitrile copolymer and the remaining polyphenylene ether forms a matrix, so that the heat resistance decreases.

The phosphate ester compound of the component (D) used in the present invention refers to all phosphate ester flame retardants. For example, trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, tripentyl phosphate, toxhexyl phosphate, tricyclohexyl phosphate, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, dicresyl phenyl phosphate, Examples thereof include phosphoric acid esters such as dimethylethyl phosphate, methyldibutylphosphate, ethyldipropylphosphate, and hydroxyphenyldiphenylphosphate, compounds obtained by modifying these with various substituents, and various condensed-type phosphoric acid ester compounds.

Of these, a phosphate compound represented by the general formula (III) is preferred.

[0023]

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(Wherein Q ₁ , Q ₂ , Q ₃ , and Q _{4 each} have 1 carbon atom)
To 6, an alkyl group or hydrogen, R ₁ , R ₂ , R
₃ , R ₄ represents a methyl group or hydrogen. n is an integer of 1 or more; n ₁ and n ₂ are integers of 0 to 2; m ₁ , m ₂ , m
₃ and m _{4 each} represent an integer of 1 to 3. )

In the general formula (III), Q ₁ , Q ₂ ,
Particularly preferred among Q ₃ and Q ₄ is hydrogen or a methyl group.

In the formula (III), R ₁ and R ₂ are preferably hydrogen, and R ₃ and R ₄ are preferably a methyl group.

In the general formula (III), n is an integer of 1 or more, and heat resistance and workability differ depending on the number. The preferred range of n is 1-5. Further, the phosphoric ester may be a mixture of n-mers.

The preferred phosphoric ester compound as the component (D) has a bonding structure of “specific bifunctional phenol” and a terminal structure of “specific monofunctional phenol”.

As the “specific bifunctional phenol”,
2,2-bis (4-hydroxyphenyl) propane [commonly known as bisphenol A], 2,2-bis (4-hydroxy-3-methylphenyl) propane, bis (4-hydroxyphenyl) methane, bis (4-hydroxy- 3,5-
Bisphenols such as, but not limited to, dimethylphenyl) methane and 1,1-bis (4-hydroxyphenyl) ethane. Particularly, bisphenol A is preferable.

As the "specific monofunctional phenol", unsubstituted phenol, monoalkylphenol, dialkylphenol, and trialkylphenol can be used alone or as a mixture of two or more. Especially phenol, cresol, dimethylphenol (mixed xylenol),
2,6-dimethylphenol and trimethylphenol are preferred.

These phosphorus compounds can be used alone or in combination of two or more.

The amount of the component (D) is 1 to 30 parts by weight based on 100 parts by weight of the total amount of the components (A), (B) and (C).
Parts by weight, preferably 2 to 20 parts by weight, more preferably 5 to 15 parts by weight. If it is less than 1% by weight, the flame-retardant effect is insufficient, and if it exceeds 30% by weight, heat resistance and mechanical properties are impaired, which is economically disadvantageous and not preferable.

It is also effective to use a flame retardant other than the phosphoric acid ester compound in combination with polytetrafluoroethylene, a silicone resin, a phenol resin, a glass fiber, a carbon fiber or the like as an anti-dripping agent.

The composition of the present invention further comprises an inorganic filler such as glass fiber, glass flake, kaolin clay, talc and the like as the component (E), and other fibrous reinforcing agents.
A high-strength composite having excellent fluidity and heat resistance can be obtained. The amount of the component (E) is from 1 to 100 parts by weight based on 100 parts by weight of the total of the components (A), (B) and (C).
Parts by weight, preferably 5 to 80 parts by weight.

In the resin composition of the present invention, a styrene-based thermoplastic elastomer such as a styrene-butadiene block copolymer, a styrene-isoprene block copolymer and a hydrogenated elastomer thereof are preferably used as an impact modifier. Can be

To the resin composition of the present invention, other additives, such as a plasticizer, an antioxidant, and an ultraviolet absorber, for imparting further properties or within the range not impairing the effects of the present invention. Stabilizers, antistatic agents, release agents, dyes and pigments, or other resins can be added.

The method for producing the composition of the present invention is not particularly limited, and the composition can be kneaded and manufactured using a kneader such as an extruder, a heating roll, a kneader, and a Banbury mixer. Among them, kneading with an extruder is preferable in terms of productivity. The kneading temperature is in the range of 250 to 360 ° C,
Preferably it is the range of 280-340 degreeC. The order of kneading may be to knead all the components at once, but (A)
After the components (B) and (C) are kneaded in advance, the components (D) and (E) can be fed from the middle of the extruder and kneaded.

[0038]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples.

The physical properties of the obtained resin composition were evaluated by the following methods and conditions.

(1) Molding fluidity: thickness 1.6 mm, width 12.7 mm, length 12 in flow direction
When a 7 mm molded piece was injection molded, the minimum molding pressure (hereinafter abbreviated as SSP) required to completely fill the molded piece was measured and used as a measure of molding fluidity. The lower the SSP value, the better the molding fluidity.

(2) Heat deformation temperature Load of 18.6 kg / cm ² based on ASTM D648
And measured as a heat resistance scale.

(3) Flexural strength and flexural modulus Measured according to ASTM D790.

(4) Izod impact strength Measured at a temperature of 23 ° C. and a notch based on ASTM D256.

(5) Flame retardancy Based on the UL-94 vertical flame test, the flame retardancy was measured using a 1/8 inch thick injection molded test piece.

The following components were used in Examples and Comparative Examples.

(1) Preparation of styrene acrylonitrile copolymer (AS-1 to AS-7) 4.7 parts by weight of acrylonitrile, 73.3 parts by weight of styrene, 22 parts by weight of ethylbenzene, and t-butyl peroxy- as a polymerization initiator A mixed solution comprising 0.02 parts by weight of isopropyl carbonate was continuously supplied at a flow rate of 2.5 liters / hour to a complete mixing type reactor having a volume of 5 liters, and polymerization was carried out at 142 ° C. The polymerization liquid is continuously led to an extruder equipped with a vent to remove unreacted monomers and a solvent under the conditions of 260 ° C. and 40 Torr, and the polymer is continuously cooled and solidified, shredded, and co-polymerized with a particulate styrene acrylonitrile. A combination (designated AS-1) was obtained. This copolymer was analyzed for its composition by infrared absorption spectroscopy. As a result, 9% by weight of acrylonitrile unit and 91% of styrene unit
% And the melt flow rate was 90 g / 10 min (measured at 220 ° C. under a load of 10 kg according to ASTM D-1238). This copolymer is designated as AS-1.

Similarly, styrene acrylonitrile copolymers (AS-2 to 7) having different copolymer compositions and different melt flow rates were prepared by changing the charged composition of the monomers and the polymerization temperature. Table 1 shows the properties of AS-1 to AS-8.

[0048]

[Table 1]

(2) Polyphenylene ether PPE-1: Poly 2,6-dimethyl-1,4-phenylene ether having a reduced viscosity ηsp / c of 0.53 dl / g measured at 30 ° C. in chloroform. PPE-2: poly 2,6-dimethyl-1,4-phenylene ether having a reduced viscosity ηsp / c measured at 30 ° C. in chloroform of 0.43 dl / g.

(3) Polystyrene PS-1: Homopolystyrene, Asahi Kasei Polystyrene 685, manufactured by Asahi Kasei Corporation. PS-2: Asahi Kasei Kogyo Co., Ltd. homopolystyrene, Asahi Kasei polystyrene 680. PS-3: rubber reinforced polystyrene manufactured by Asahi Kasei Corporation,
Asahi Kasei polystyrene 403.

(4) Phosphate ester FR-1: a mixture of n = 1 to 3 represented by the chemical formula (IV).

[0052]

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FR-2: n = 1 represented by the chemical formula (V)
A mixture of ~ 3.

[0054]

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(5) Glass fiber GF-1: aminosilane surface-treated, fiber length 3 mm
Chopped strand.

(Examples 1 to 13, Comparative Examples 1 to 15) Table 2
The maximum temperature of the heating cylinder is 3
The mixture was fed to a twin-screw extruder set at 20 ° C and melt-kneaded to obtain a composition pellet. Injection molding was performed using the pellets, and evaluation of molding fluidity and physical properties were performed using the obtained molded pieces. The results are shown in Tables 2 to 5.

[0057]

[Table 2]

[0058]

[Table 3]

[0059]

[Table 4]

[0060]

[Table 5]

[0061]

The resin composition of the present invention has a better balance of fluidity, heat resistance, mechanical properties and the like than the conventional composition of polyphenylene ether and styrene resin, and furthermore has good flame retardancy. It provides a material that is excellent and has excellent moldability, heat resistance in practical use, and mechanical properties.

[Brief description of the drawings]

FIG. 1 shows the relationship between a change in loss elastic modulus (E ″) and temperature by measuring dynamic viscoelastic behavior of a component resin and a composition.

────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification symbol FI C08L 33/20 C08L 33/20 (56) References JP-A-6-306254 (JP, A) JP-A-61-43647 (JP) , A) JP-A-60-11549 (JP, A) JP-A-58-129049 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 1/00-101/16

Claims (4)

(57) [Claims] (A) polyphenylene ether 30 to 9
5% by weight, (B) 2 to 60% by weight of polystyrene and / or rubber-modified polystyrene, (C) 3 to 40% by weight of a styrene-acrylonitrile copolymer containing an acrylonitrile component of 7 to 11% by weight. The melt flow rate of the component (C) (220 ° C., 1
(Under 0 kg load) of 5 to 100 g / 10 min. 2. A thermoplastic resin composition, further comprising (D) 1 to 30 parts by weight of a phosphoric ester compound based on 100 parts by weight of the resin composition of claim 1. 3. A thermoplastic resin composition further comprising (E) 1 to 100 parts by weight of an inorganic filler based on 100 parts by weight of the resin composition of claim 1. 4. The resin composition according to claim 1, further comprising 1 to 30 parts by weight of (D) a phosphate ester compound and 1 to 100 parts by weight of an inorganic filler (E). A thermoplastic resin composition comprising: