JPH06145445A - Production of styrenic resin composition - Google Patents

Abstract

PURPOSE:To obtain a method for producing a styrenic resin composition excellent in strength and transparency. CONSTITUTION:This method for producing a styrenic resin composition is characterized by dissolving a terpenic resin in a raw material solution consisting essentially of a styrenic monomer and polymerizing the monomer in a method for producing a styrenic resin composition composed of the styrenic resin and the terpenic resin.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a styrene resin composition.

[0002]

BACKGROUND OF THE INVENTION Styrenic resins have been widely used as molding materials for household products, electric appliances and the like because they are resins having excellent transparency, moldability and rigidity. As the fields of application have expanded, it has become increasingly necessary to improve the strength of styrene resins, and methods such as increasing the molecular weight and optimizing the molecular weight distribution have been implemented, but they have not yet met the market demands. . In order to improve the strength of the styrene resin, a method of blending polystyrene and a styrene-butadiene block copolymer is widely used as a general method, but this resin composition has a large decrease in transparency as compared with polystyrene. , It has not yet met the demands of the market.

Further, especially in the field of sheets, low temperature molding and improvement of deep drawing moldability are required, but there is a limit to improvement in the case of a styrene resin composition obtained by blending polystyrene and a block copolymer. It has also been pointed out that when the molded product is trimmed, the molded product is cracked and the strength is insufficient.

Attempts have been made to copolymerize with a second copolymerizable monomer, such as butyl acrylate, but the strength of the molded product is extremely poor. Also, blend resins of the above copolymer and a styrene-butadiene block copolymer have been tried. For example, as described in Japanese Patent Publication No. 62-250701, this resin has many problems such as low strength, low surface hardness, and poor chemical resistance.

JP-A-62-169812 describes a method of polymerizing a mixed solution of styrene, butyl acrylate, methyl methacrylate and a styrene-butadiene block copolymer. The thermoplastic resin polymerized by this method has been improved in transparency, impact strength, etc. to the extent that market demands are met, but when the sheet is subjected to secondary heat molding, the surface of the molded product becomes glossy and the transparency is high. It has a big problem that it decreases.

Further, as a characteristic of the rubber-reinforced resin containing the rubber-like elastic material as dispersed particles, there is a problem that the folding strength is fragile. A method of blending a styrene-butadiene block copolymer with such a resin is also known, but when a styrene-acrylic acid (methacrylic acid) ester copolymer and a styrene-butadiene block copolymer are blended, the styrene-butadiene block copolymer is The dispersibility of the polymer is poor, resulting in a decrease in transparency.

[0007]

Means for Solving the Problems The inventors of the present invention have made extensive studies in order to solve the above-mentioned problems, and as a result, have found that a terpene resin is dissolved in a raw material solution containing a styrene monomer as a main component. Then, it was found that the above problems can be solved by polymerizing this raw material solution to obtain a styrene resin composition, and completed the present invention.

The present invention will be described in detail below. The styrene resin referred to in the present invention is a resin composed of a styrene monomer such as styrene, α-methylstyrene, p-methylstyrene or the like alone or a mixture thereof, and a styrene polymer composed of the styrene monomer as a continuous phase. And a rubber-reinforced styrene resin (so-called HIPS resin) having a rubber-like elastic body as a dispersed phase, methyl methacrylate, butyl methacrylate,
A rubber composed of an acrylate (methacrylate) -based monomer such as butyl acrylate and ethyl acrylate and a styrene-based monomer, and a polymer composed of a styrene-based monomer and an acrylate (methacrylate) -based monomer as a continuous phase, and rubber. Examples include rubber-reinforced styrene-based resins having the elastic body as a dispersed phase, and transparent styrene-based resins having a continuous phase and a dispersed phase having the same refractive index.

The terpene-based resin referred to in the present invention is a Friedel-Crafts type catalyst for dipentene and aromatic hydrocarbons obtained by isomerization of d-limonene obtained from citrus cortex or α-pinene obtained from raw pine resin. For example, it can be obtained by performing cationic polymerization using aluminum chloride, boron trifluoride, etc.). The resin obtained by hydrogenating this polymer is also the terpene resin in the present invention. There is no particular restriction on the hydrogenation rate.

Aromatic hydrocarbons include styrene and α-
Methylstyrene, vinyltoluene and the like are preferably used. The degree of polymerization of the terpene-based resin is not particularly limited, but the degree of polymerization is 1000 or less, preferably 500 or less, more preferably 200 or less. When the degree of polymerization is high, the dissolution rate in the raw material solution mainly composed of styrenic monomer becomes slow,
Further, the viscosity of the raw material solution in which the terpene resin is dissolved becomes high, which is not preferable. Furthermore, the effect of increasing transparency and the effect of dispersing the block SBR and the like decrease, which is not preferable.

Examples of the terpene-based resin include YS resin TO-125 and TO-, manufactured by Yasuhara Chemical Co., Ltd.
115, TO-105, TO-85 and CLEARON M-
115, M-105, P-85 (all are trade names of Yasuhara Chemical Co., Ltd.) and the like can be used. The present invention, when producing the styrene resin composition, a styrene monomer, an acrylate (methacrylate) monomer,
A terpene-based resin is dissolved in a raw material solution composed of a rubber-like elastic material, a polymerization solvent, a polymerization aid, etc., and this raw material solution is often used in a usual styrene-based resin production method, such as a solution polymerization method, a bulk polymerization method, and a suspension method. A styrene resin composition is produced by a batch method or a continuous method using a polymerization method, a bulk-suspension polymerization method, or the like.

There is no particular limitation on the amount of the terpene resin dissolved in the raw material solution containing styrene monomer as a main component. It is set from the quality setting of the final styrenic resin composition.
0 wt% or less is preferably used. There is no particular limitation on the method of adding the terpene resin. Directly adding flaky or pelletized terpene resin to the raw material solution tank, a method of dissolving, after manufacturing the terpene resin, before processing into flakes or pellets, or after styrene monomer or polymerization solvent such as , Ethylbenzene, dissolved in toluene, etc.,
A method in which the terpene-based resin solution is added to the raw material tank or continuously supplied to the main raw material solution line and mixed in the pipe before entering the reactor can be used.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is not limited to these examples. The methods for measuring the physical properties in the examples are as follows. MFR: According to ISO R1133. IZOD IMPACT: According to ASTM D256. Transparency (Haze): According to ASTM D1003.

In the case of an injection molded product, a color chip having a thickness of 2.5 mm is used, and in the case of a sheet, a sheet having a thickness of 0.3 mm is used. Glossiness: After heating the sheet at 120 ° C. for 5 seconds, a drink cup is formed by pressure forming, and the difference in transparency between the sheet and the beverage cup before forming is visually judged.

⊚: Transparency equivalent to that before molding. ◯: Decreased transparency and looks whitish compared to before molding. Impact strength: 5 cm x 8.8 c from the sheet
Cut out a test piece of m and use the "falling weight type graphic impact tester" from Toyo Seiki Seisakusho, height 20 cm
The maximum load for destruction is calculated by letting a missile with a mass of 6.5 kg fall naturally. Sheet appearance: Judge the sheet with the naked eye.

⊚: Smooth state, ∘: Gelled material is observed here and there.

[0017]

【Example】

[0018]

Example 1 Two reactors equipped with a stirrer were connected in series,
After that, a styrene-based polymer is produced using a polymerization device in which a twin-screw extruder with a two-stage vent is arranged. Styrene 44.
6 parts by weight, 9.40 parts by weight of butyl acrylate, 31.2 parts by weight of methyl methacrylate, B as a rubber-like elastic body
-S type (B: butadiene block, S: styrene block), 6.1 parts by weight of a rubber-like elastic body having a styrene content of 30% by weight, 2.6 parts by weight of ethylbenzene,
0.01 parts by weight of 1,1 bis (t-butylperoxy) cyclohexane, terpene resin Clearon M115
(Yasuhara Chemical Co., Ltd. trade name) 6.1 parts by weight of a raw material solution is supplied to a reactor to carry out polymerization. Polymerization temperature is 1
30 ° C and 150 ° C.

The physical properties of the styrene resin composition obtained are shown in Table 1.

[0020]

Example 2 100 parts by weight of the styrene-based resin composition obtained in Example 1 and 5 parts by weight of styrene-butadiene block copolymer Toughprene 125 (trade name of Asahi Kasei Kogyo Co., Ltd.) were blended and uniaxially extruded. A sheet having a thickness of 0.3 mm is formed by a machine. Table 2 shows the physical properties of the sheet.

[0021]

Comparative Example 1 A styrene polymer is obtained by polymerizing under the same formulation and conditions as in Example 1, except that the terpene resin is not dissolved. 100 parts by weight of this styrene-based polymer and 8 parts by weight of a terpene-based resin Clearon M115 (trade name of Yasuhara Chemical Co., Ltd.) are pellet-blended and granulated with a single-screw extruder to obtain a styrene-based resin composition. The physical properties are shown in Table 1.

[0022]

Comparative Example 2 100 parts by weight of the styrene polymer obtained in Comparative Example 1, 8 parts by weight of the terpene resin Clearon M115 (trade name of Yasuhara Chemical Co., Ltd.), Toughprene 125 (trade name of Asahi Kasei Co., Ltd.) 5.5 Blend parts by weight and granulate with a single screw extruder. Using the obtained pellets, the same operation as in Example 2 is performed to obtain a sheet. Table 2 shows the physical properties of the obtained sheet.

[0023]

[Table 1]

[0024]

[Table 2]

[0025]

The styrene resin composition obtained by the method of the present invention is excellent in physical properties, particularly transparency and strength, as compared with the styrene resin composition obtained by pellet blending.
Also, when blended with a styrene-butadiene block copolymer, it is excellent in the transparency of the sheet, the luster regain in secondary molding, and the strength.

Further, in the case of the styrene resin compositions of Comparative Example 1 and Comparative Example 2, good injection molded articles and sheets cannot be obtained unless they are once pelletized by a single screw extruder. Also, when pelletizing with a single-screw extruder, a surging phenomenon frequently occurs, resulting in a large loss. On the contrary, when the styrene-based resin composition obtained by the method of the present invention is used, a good molded product can be obtained even by pellet-blending with a styrene-butadiene block copolymer and sheet forming, that is, obtained by the method of the present invention. The styrenic resin composition thus obtained is remarkably excellent in moldability.

Claims (1)

[Claims] 1. A method for producing a styrene resin composition comprising a styrene resin and a terpene resin, wherein the terpene resin is dissolved in a raw material solution containing a styrene monomer as a main component and polymerized. A method for producing a styrene-based resin composition, comprising: