KR19980027068A - Styrenic resin composition - Google Patents

Abstract

The present invention relates to a styrene resin composition, and more particularly, to an acrylonitrile-butadiene-styrene copolymer, a styrene-acrylonitrile-maleimide copolymer, and a processing aid of styrene-acrylonitrile and conventional additives. The present invention relates to a styrene-based resin composition suitable for blow molding of automobile spoilers due to excellent impact strength and mechanical strength, uniform appearance of molded products after molding, and improved melt strength and elongation.

Description

Styrenic resin composition

The present invention relates to a styrene resin composition, and more particularly, to an acrylonitrile-butadiene-styrene copolymer, a styrene-acrylonitrile-maleimide copolymer, and a processing aid of styrene-acrylonitrile and conventional additives. The present invention relates to a styrene-based resin composition suitable for blow molding of automobile spoilers due to excellent impact strength and mechanical strength, uniform appearance of molded products after molding, and improved melt strength and elongation.

In general, the physical properties of resins required for blow molding automotive spoilers maintain impact strength and mechanical strength, make the appearance of molded products even after molding, and have excellent melt strength and elongation at blow molding, and maintain high heat resistance. Therefore, the deformation according to external environment should be small.

Conventionally, a method of adding polytetrafluoroethylene resin has been proposed as a method for imparting melt strength and melt elongation to be suitable for blow molding of styrene-based resin, but a styrene-based resin composition prepared by such a method is generally Melt strength and elongation are excellent but the mechanical properties of the resin is lowered because there is no compatibility between resins, in particular, there is a problem that the surface of the molded product is uneven.

In addition, the resin developed for automobile spoiler molding has been modified by General Electric's modified polypropylene oxide, but the weather resistance is weak and the molding shrinkage rate during molding is high, resulting in many difficulties in designing the product. To increase the non-uniformity and improve the heat resistance there is a problem that the workability is greatly reduced. On the other hand, in the automotive field, since the appearance of the molded article may be deformed or degraded when exposed to external adverse conditions for a long time, it is necessary to improve the heat resistance of the structural material to exhibit high performance.

US Pat. Nos. 3,010,936 and 4,659,790 disclose methods for manufacturing heat resistant ABS resins by replacing part or all of styrene with α-methylstyrene as a method for improving heat resistance of such automobile structures.

In addition, Japanese Patent Application Publication Nos. 58-206657, 59-135210, 59-184243, 63-162708, 63-235350 and US Pat. No. 4,757,109 include a maleimide compound to produce a heat resistant ABS resin. Is disclosed. In addition, a method of kneading a polycarbonate resin and an ABS resin, a method of filling an inorganic material, and the like are known.

However, when the heat-resistant resin is manufactured using α-methyl styrene in the above method, there is a problem in that thermal stability is poor during processing and there is a limit in improving heat resistance. In addition, when kneading a polycarbonate resin and an ABS resin, there are some problems such as workability and chemical resistance, and the price is high, so there is a limit to use, and there is a problem in that impact resistance is lowered when the inorganic material is filled.

The present inventors adjust the rubber content and molecular weight of the ABS resin and the molecular weight of the styrene-acrylonitrile copolymer and add a copolymer containing a maleimide compound to improve melt strength, melt elongation and heat resistance, and thus are suitable for blow molding. The present invention was completed by knowing.

SUMMARY OF THE INVENTION An object of the present invention is to provide a blow molding styrene resin composition which maintains the surface of the spoiler evenly after molding and retains weather resistance and impact resistance.

In the styrene resin composition, (A) a weight average molecular weight produced by polymerizing two or more compounds selected from aromatic vinyl compounds, vinyl cyanide compounds, and maleic anhydride compounds with a diene rubber component or an alkyl acrylate rubber component 100,000 Weight average molecular weight 100,000 prepared by polymerizing 20 to 80% by weight of a graft copolymer (A-1) of 2 to 300,000 and at least two compounds selected from aromatic vinyl compounds, vinyl cyanide compounds and alkyl ester compounds of acrylic acid or methacrylic acid 10 to 40% by weight of copolymer (A-2) of 30 to 300,000 and 20 to 60 weight of copolymer (A-3) having a weight average molecular weight of 50,000 to 300,000 prepared by polymerizing aromatic vinyl compound, vinyl cyanide compound and maleimide compound 100 parts by weight of a basic resin composed of%, (B) an aromatic vinyl compound, a vinyl cyanide compound, and acrylic or methacrylic acid It is characterized by consisting of 0.1 to 8.0 parts by weight of a copolymer having a weight average molecular weight of 500,000 to 2,000,000 and (C) normal additives prepared by polymerizing two or more compounds selected from alkyl ester compounds of (C).

Referring to the present invention in more detail as follows.

The present invention relates to a styrene resin composition suitable for blow molding of automobile spoilers.

In blow molding, the most important physical property of the resin is the melt strength that prevents the increase of the parison produced during the blow molding, and the degree to which the parison can be expanded without breaking the form when inflating the parison with air. The melt elongation shown can be mentioned.

Melt strength depends on the rubber content of the graft copolymer (A-1), the molecular weight of the grafted component, and the molecular weight of the copolymer (A-2). As the rubber content of the graft copolymer (A-1) increases, the melt strength decreases. As the molecular weight of the graft copolymers (A-1) and (A-2) increases, the melt strength increases. . On the contrary, in the case of the melt elongation, the melt elongation increases when the rubber content of the graft copolymer (A-1) increases, and when the molecular weight of the graft copolymer (A-1) or (A-2) increases, the melt elongation increases. Elongation will decrease.

Therefore, the present inventors prepared a styrene resin having melt strength and elongation at break suitable for blow molding by adjusting the rubber content and molecular weight of the graft copolymer (A-1) and the molecular weight of the copolymer (A-2).

Graft copolymer (A-1) is contained in 20 to 80 weight% with respect to the base resin for blow molding of this invention. If the graft copolymer (A-1) is used at less than 20% by weight, the impact strength is severely deteriorated. On the other hand, when the graft copolymer (A-1) is used in excess of 80% by weight, blow molding may occur due to a decrease in melt strength of the resin composition. Not desirable to

The copolymer (A-2) is preferably added in an amount of 10 to 40% by weight based on the base resin for blow molding. At this time, if the content is less than 10% by weight, there is a problem in moldability, and when used in excess of 40% by weight, a problem of deterioration of physical properties occurs.

The weight average molecular weight of the graft copolymer (A-1) and the copolymer (A-2) is preferably 100,000 to 300,000. If the average molecular weight is less than 100,000, it is difficult to expect satisfactory melt strength, whereas If exceeded, it is unfavorable for blow molding because of a decrease in melt elongation.

On the other hand, the copolymer (A-3) is preferably 20 to 60% by weight based on the base resin for blow molding. If the content is less than 20% by weight, the heat resistance improvement is small, and if the content exceeds 60% by weight, the impact strength and the elongation at break are not preferable. At this time, the monomer composition ratio of the copolymer (A-3) is preferably 30 to 65% by weight of the aromatic vinyl compound, 10 to 25% by weight of the vinyl cyanide compound and 15 to 45% by weight of the maleimide compound.

In the copolymer (A-3), the aromatic vinyl compound is at least one selected from styrene, α-methylstyrene, α-ethylstyrene, ο-ethylstyrene, ρ-ethylstyrene, 2,4-dimethyl styrene and vinyl toluene The vinyl cyanide compound may be at least one selected from acrylonitrile, methacrylonitrile and ethacrylonitrile, and the maleimide compound may be selected from N-phenylmaleimide, N-methylmaleimide, and cyclohexyl maleimide. It is more than that. In the copolymer (A-3), when the aromatic vinyl compound is used in an amount less than 30% by weight, the workability and impact strength are lowered, and when it is used in excess of 65% by weight, the heat resistance is lowered. In addition, when the vinyl cyanide compound is used in less than 10% by weight, workability and impact strength decrease, and when used in excess of 25% by weight, discoloration occurs during processing. Meanwhile, a weight average molecular weight of 500,000 to 2,000,000 prepared by polymerizing two or more compounds selected from an aromatic vinyl compound, a vinyl cyanide compound, an alkyl ester compound of acrylic acid or methacrylic acid with respect to 100 parts by weight of the base resin for blow molding Copolymer (B) is added at 0.1-8.0 parts by weight. If the content is less than 0.1 parts by weight, there is a problem of sag, and if it exceeds 8.0 parts by weight, the melt strength increases while the melt elongation is greatly reduced.

Copolymer (B) is a resin for application to large parts such as automotive spoilers need to minimize the melt strength is added to improve this.

In addition to such components, lubricants, heat stabilizers, light stabilizers and the like can be added as usual additives.

Hereinafter, the present invention will be described in detail with reference to the following Examples, which are not intended to limit the scope of the present invention.

Preparation Example 1 ; Preparation of Graft Copolymer (A-1)

2,000 g of butadiene, 2,000 g of ion-exchanged water, 4 g of sodium lauryl sulfate, and 2 g of t-dodecyl mercaptan were added to the closed reactor to prepare a polybutadiene latex.

3,000 g of polybutadiene latex thus prepared, 3,000 g of ion-exchanged water, 1,140 g of styrene, 360 g of acrylonitrile, 6 g of sodium laurylsulfate and 2 g of t-dodecyl mercaptan were placed in a new closed reactor. When reached to 70 ℃ 2 g of potassium persulfate was added and polymerized for 3 hours to obtain a polymer having a weight average molecular weight of 180,000, which was made into a dry powder through a post-treatment process.

The copolymer obtained here is an acrylonitrile-butadiene-styrene copolymer (ABS).

Preparation Example 2 ; Preparation of Copolymer (A-2)

In a closed reactor, 4,000 g of ion-exchanged water, 1,520 g of styrene, 480 g of acrylonitrile, 8 g of t-dodecyl mercaptan, and 10 g of sodium lauryl sulfate were added, and potassium persulfate was added at 70 ° C. to emulsify for 8 hours. The polymerization yielded a copolymer having a weight average molecular weight of 200,000.

The copolymer obtained here is a styrene-acrylonitrile copolymer (SAN).

Preparation Example 3 ; Preparation of Copolymer (A-3)

In a nitrogen-substituted closed reactor, 4,000 g of ion-exchanged water, 60 g of alkylbenzene sulfonic acid salt, 800 g of styrene, 200 g of acrylonitrile, 500 g of N-phenylmaleimide, and 10 g of t-dodecyl mercaptan were added thereto. 10 g of potassium persulfate was collectively administered while raising the reactor temperature to 70 ° C. to initiate the reaction, and the temperature was raised to 80 ° C. for 1 hour, followed by 9,000 g of ion-exchanged water, 100 g of alkylbenzene sulfonate salt, and 4,000 styrene in two steps. g, acrylonitrile 1,500 g, 2,500 g N-phenylmaleimide, 500 g methacrylamide, 10 g t-dodecyl mercaptan and 25 g potassium persulfate were continuously administered over 4 hours. After the addition, 1,000 g of ion-exchanged water, 10 g of alkylbenzene sulfonate salt, and 5 g of potassium persulfate solution were collectively administered and stirred for 1 hour to complete the polymerization.

The copolymer obtained here was called heat resistant SAN.

Preparation Example 4 ; Preparation of Copolymer (B)

In a closed reactor, 4,000 g of ion-exchanged water and 10 g of sodium lauryl sulfate were added and the temperature was raised to 70 ° C., followed by 1,520 g of styrene, 480 g of acrylonitrile, 0.5 g of t-dodecyl mercaptan and 2 g of potassium persulfate. Emulsion polymerization was added over 6 hours to prepare a copolymer having a weight average molecular weight of 1,200,000.

Here, the obtained copolymer was called SAN processing aid.

Example 1

60 wt% ABS resin having a weight average molecular weight of 180,000 and 200,000 wt% of a styrene-acrylonitrile (SAN) copolymer having a weight average molecular weight of 200,000, and a heat-resistant SAN 20. Weight%, SAN processing aid 2.0 parts by weight, 0.5 parts by weight of magnesium stearate, 1.0 parts by weight of ethylene bis stearic acid amide, 0.5 parts by weight of diphenylisooctyl phosphite and 0.5 parts by weight of magnesium oxide uniformly mixed with a Hanschel mixer Extruded into pellet to make pellets.

Example 2

The resin was pelletized in the same manner as in Example 1, except that 50 wt% of ABS and 30 wt% of heat resistant SAN were used.

Example 3

The resin was pelletized in the same manner as in Example 1, except that the components of Example 1 were changed to 40 wt% ABS and 40 wt% heat resistant SAN.

Comparative Example 1

Resin was prepared in the same manner as in Example 3, except that the mixing ratio of ABS and SAN in the component of Example 3 was changed to 10:50 weight ratio.

Comparative Example 2

A resin was prepared in the same manner as in Example 3, except that the mixing ratio of ABS and SAN in the component of Example 3 was changed to a 30:30 weight ratio.

Comparative Example 3

Resin was prepared in the same manner as in Example 3, except that the SAN processing aid of the components of Example 3 was not used.

Comparative Example 4

Resin was prepared in the same manner as in Example 3, except that the SAN processing aid of the components of Example 3 was changed to 4.0 parts by weight.

Comparative Example 5

Resin was prepared in the same manner as in Example 3, except that the SAN processing aid of the components of Example 3 was changed to 6.0 parts by weight.

Experimental Example

Melt Strength, Melt Elongation, Izod Impact Strength, Heat Deflection Temperature, Tensile Strength, Elongation, Flexural Strength, Flexural Modulus, Flowability and Molding of Pelletized Samples Prepared According to Examples 1 to 3 and Comparative Examples 1 to 5 Shrinkage was measured and the results are shown in Table 2. Here, the melt strength and the elongation were measured for 2 hours by drying each pellet in a hot air dryer at 80 ° C. and then using Rheotens (Gottfer, Germany) at 210 ° C. and 230 ° C. diodes. Other physical properties were measured by injection molding the physical specimens using a 5 oz injection machine.

Izod impact strength was measured by ASTM D256 method, tensile strength, elongation, flexural strength and flexural modulus were measured by ASTM D790 method, heat deformation temperature was measured by ASTM D648 method, and fluidity was measured by ASTM D1238 method.

division Example Comparative Example One 2 3 One 2 3 4 5 ABS (% by weight) 60 50 40 10 30 40 40 40 SAN (% by weight) 20 20 20 50 30 20 20 20 Heat-resistant SAN (% by weight) 20 30 40 40 40 40 40 40 SAN processing aid (parts by weight) 2.0 2.0 2.0 2.0 2.0 - 4.0 6.0 Magnesium Stearate (parts by weight) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Ethylenebisstearic acid amide (parts by weight) 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Diphenyl isooctyl phosphite (parts by weight) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Magnesium oxide (parts by weight) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5

division Example Comparative Example One 2 3 One 2 3 4 5 Melt strength (cN) 210 ℃ 15.6 18.2 20 24.2 22 18.2 22.3 26 230 ℃ 5 6.9 8.5 10.3 9.4 8.4 10.7 13.6 Melt Elongation (cm / sec) 210 ℃ 47 44 40 37 39 43 38 35 230 ℃ 38 35 32 30 31 32 31 30 Izod impact strength (kg.cm/cm, 1/41) 27 20 15.5 6 12 17 15.2 13.7 Heat Deflection Temperature (18.5kgf, 1/41) 95.6 98.5 101.5 103 102.1 102 104.8 105.2 Tensile Strength (kg / ㎠, 1/81) 432 456 493 657 546 478 532 564 Elongation (%, 1/81) 41 35 28 17 25 29 23 17 Flexural Strength (kg / ㎠, 1/81) 578 642 685 756 724 673 700 721 Flexural modulus (kg / ㎠, 1/81) 20410 21800 23300 26700 24800 22750 23900 25100 Fluidity (g / 10 min, 220 ° C / 10 kg) 3.4 3.4 3.6 3.8 3.6 3.7 3.0 2.4 Mold Shrinkage (%) 0.4 to 0.6 0.4 to 0.6 0.4 to 0.7 0.5 to 0.8 0.4 to 0.6 0.4 to 0.6 0.4 to 0.6 0.4 to 0.6

As shown in Table 2, the styrene-based resin composition of the present invention has excellent melt strength, melt elongation, impact strength, and low molding shrinkage, thus making the appearance even, and thus suitable for blow molding of automotive spoilers. have.

Claims (4)

In the styrene resin composition, (A) a weight average molecular weight of 100,000 to 300,000 prepared by polymerizing two or more compounds selected from aromatic vinyl compounds, vinyl cyanide compounds and maleic anhydride compounds with diene rubber components or alkyl acrylate rubber components A weight average molecular weight of 100,000 to 300,000 prepared by polymerizing 20 to 80% by weight of the graft copolymer (A-1) and at least two compounds selected from aromatic vinyl compounds, vinyl cyanide compounds and alkyl ester compounds of acrylic acid or methacrylic acid. 10-40 wt% of copolymer (A-2) and 20-60 wt% of copolymer (A-3) having a weight average molecular weight of 50,000-300,000 prepared by polymerizing aromatic vinyl compound, vinyl cyanide compound and maleimide compound 100 parts by weight of the base resin, and (B) an aromatic vinyl compound and a vinyl cyanide compound, an acrylic acid or an alkyl of methacrylic acid A styrene resin composition comprising 0.1 to 8.0 parts by weight of a copolymer having a weight average molecular weight of 500,000 to 2,000,000 prepared by polymerizing two or more compounds selected from a steer compound, and (C) a normal additive. The method of claim 1, wherein the aromatic vinyl compound is one or more selected from styrene, α-methylstyrene, α-ethylstyrene, O -ethylstyrene, ρ-ethylstyrene, 2,4-dimethylstyrene and vinyl toluene A styrene resin composition characterized by the above-mentioned. The styrene-based resin composition according to claim 1, wherein the vinyl cyanide compound is at least one selected from acrylonitrile, methacrylonitrile and ethacrylonitrile. The styrene resin composition according to claim 1, wherein the maleimide compound is at least one selected from N-phenylmaleimide, N-methylmaleimide, and cyclohexyl maleimide.