JPH1017620A - Styrene copolymer and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a styrene copolymer having sufficient melt viscoelasticity and being excellent in moldability, etc., and a process for producing the same. SOLUTION: This invention provides a styrene copolymer comprising 100-40wt.% units (A) derived from a styrene compound, 0-60wt.% units (B) derived from other copolymerizable compounds and 0.001-2 pts.wt., per 100 pts.wt. total of units A and B, units (C) derived from a reactive double metal carboxylate represented by the formula: M (Acid1 )x (Acid2 )N-x (wherein M is a metal having a positive valence of N, Acid1 is an α,β-ethylenically unsaturated carboxylic acid, Acid2 is a carboxylic acid other than Acid1 and X (≠0, X<N) and N-X (≠0) are the numbers of moles necessary to form a salt with metal M, respectively) and a process for producing the same, which comprises dissolving 0.001-2 pts.wt. reactive double metal carboxylate represented by the formula in 100 pts.wt. styrene monomer or a mixture thereof with at least one copolymerizable monomer and radical-polymerizing the monomers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a styrene copolymer containing a reactive carboxylic acid metal complex unit as an essential component and a method for producing the same, and is particularly useful as a blow molding or foam molding material. Styrenic copolymers.

[0002]

2. Description of the Related Art Among aromatic vinyl resins, styrene resins are inexpensive and have excellent transparency, moldability and rigidity, and are widely used in molding materials such as household goods and electric appliances. These molded products are obtained by injection molding or vacuum / pressure molding from a sheet. In particular, polystyrene sheets and foam boards are widely used in food packaging applications and the like. However, when secondary processing from such a sheet or foam board to a deep drawn product such as a food container, the product tends to have uneven thickness due to the dripping phenomenon caused by heating and melting, and the product is cracked due to insufficient stretchability. , Tears and the like are likely to occur.

[0003] Further, in the use of a styrene resin as a blow molding material, in order to produce a molded article having excellent moldability in the process of producing a series of molded articles and free from defects such as uneven thickness, parison formation is required. A material excellent in die swell characteristics and drawdown resistance at the time is required, and in order to satisfy these, it is desired that the material has excellent melt viscoelastic characteristics. In addition, in order to reduce the occurrence of defects during the molding of various types of styrenic resins and maintain high productivity, and to produce molded articles free from defects such as cracks due to impact, especially sheets, film-like processed products, foaming In the field of processed products, demands for materials having high fluidity in a molten state and excellent physical properties such as a melt tension value, melt stretchability, and processing stability are increasing.

In general, as a method of controlling the viscoelastic properties of amorphous polymers such as polystyrene in a molten state, a method of increasing the molecular weight is known. However, simply increasing the molecular weight causes a decrease in fluidity. However, it is not preferable because productivity is lowered. As a method for solving this problem, a method for widening the molecular weight distribution of the resin has been proposed, and Japanese Patent Publication No. 57-30843 and Japanese Patent Publication No.
No. 61231 discloses a method of blending high molecular weight polystyrene and low molecular weight polystyrene or obtaining a resin composition having a wide molecular weight distribution by using a multi-stage polymerization method. However, this method is not preferable from the viewpoint of industrial implementation that the manufacturing process becomes complicated and the manufacturing cost increases.

Further, Japanese Patent Application Laid-Open Nos.
In order to obtain a resin composition having a wide molecular weight distribution, a compound containing a plurality of vinyl groups at the time of polymerization reaction, for example, a difunctional or polyfunctional vinyl monomer such as divinylbenzene, diacrylate, dimethacrylate, etc. Are disclosed to introduce a crosslinked structure by covalent bond. However, in this method, since a compound containing a plurality of vinyl groups is used, covalent cross-linking is generated during the polymerization reaction, which contains a gel-like substance or increases the viscosity of the polymerization solution, which is not preferable in production. Has problems.
If the addition amount of the polyfunctional vinyl group-containing compound is limited to a very small amount in order to avoid this, there is a problem that a sufficient improvement effect cannot be obtained.

On the other hand, a method for improving the resin's melt viscoelastic properties by metal ion crosslinking is known as an ionomer. Ionomer (ion-crosslinked copolymer)
Is a thermoplastic polymer material that has been copolymerized while containing an acidic functional group such as a carboxyl group, and is neutralized with a cation such as a metal ion. When the resin is in a molten state, it exhibits the behavior of a thermoreversible gel that loosens the cross-linking between molecules and allows free thermoforming, and improves heat resistance, scratch resistance, mechanical properties, etc. It is known that the adhesion to different kinds of polymer materials is also improved.

[0007] However, in general, improvement of resins by ionomers has been mainly applied to ethylene resins.
This is because the ethylene-based ionomer has a glass transition temperature much lower than the molding temperature in the amorphous phase, so that the mobility of the polymer chains is very high in the thermoforming temperature range, and crosslinking between molecules is easily performed. Lowering the sex,
In addition, although good moldability is obtained because the crystallinity is also reduced, in the case of an aromatic vinyl ionomer, the glass transition temperature of the amorphous phase is high, and the temperature difference from the thermoforming temperature region is small. Because of its small size, there is a problem that the flowability is significantly impaired if an attempt is made to introduce a large amount of ionic cross-linking, and the melt drawability decreases as the melt tension value (hereinafter, referred to as the melt tension value) increases. This is because it is difficult to apply to styrene resins.

In Japanese Patent Application Laid-Open No. 4-258612, attempts have been made to obtain a material having excellent moldability by controlling the melt tension of a styrenic resin, but this method also controls the amount of ionic cross-linking. Although it is possible to increase the melt tension value, the melt stretchability decreases as the melt tension value increases, and the stretchability also becomes insufficient at the time of forming a sheet etc., resulting in a decrease in moldability, cracking of the product, tearing, etc. It has the disadvantage of being undesirable. In addition, since dimethylformamide, which is a polar solvent having a high boiling point, is used as a solvent for zinc diacrylate, it is difficult to completely remove dimethylformamide in the devolatilization step after the completion of polymerization, and the resin is affected by the residual dimethylformamide. It also has drawbacks such as off-flavor and coloring.

[0009]

As described above, in the aromatic vinyl ionomer, there has been a need to develop a material having good moldability while maintaining the melt viscoelastic performance enhanced by ionic crosslinking. Was desired. Accordingly, the present invention has a sufficient melt viscoelasticity in view of the current situation,
In particular, it is an object of the present invention to provide a styrene copolymer excellent in properties such as fluidity, melt tension value, melt drawability, die well, drawdown resistance and the like, which are properties relating to moldability, and a method for producing the same. .

[0010]

That is, the styrenic copolymer of the present invention has 100 units of the styrenic compound (A).
To 40% by weight, other copolymerizable compound unit (B)
Is 0 to 60% by weight and a total of 100 parts by weight of (A) and (B) is represented by the following chemical formula: M (Acid ₁ ) _X (Acid ₂ ) _NX (where M is a metal having a cation valence of N) And Aci
d ₁ is an α, β-ethylenically unsaturated carboxylic acid,
Acid ₂ is another carboxylic acid different from Acid ₁ . X (≠ 0, X <N) and NX (≠ 0) represent the number of moles of salt formed with respect to metal M of Acid ₁ and Acid ₂ respectively. A styrene-based copolymer obtained by copolymerizing the reactive carboxylic acid metal complex unit (C) in the ratio of 0.001 to 2 parts by weight is used as a solution.

The method for producing a styrenic copolymer according to the present invention is based on 100 parts by weight of a styrenic monomer alone or a mixture thereof with at least one other copolymerizable monomer. The following chemical formula: M (Acid ₁ ) _X (Acid ₂ ) _NX (where M is a metal having a cation valency of N,
₁ is an α, β-ethylenically unsaturated carboxylic acid;
id ₂ is different from other carboxylic acids and Acid _1. X (≠ 0, X <N)) and NX (≠ 0) represent the number of moles of a salt M formed with the metal M of Acid ₁ and Acid ₂ , respectively. 0.00
The solution is to dissolve at a ratio of 1 to 2 parts by weight and to carry out radical polymerization.

The styrenic copolymer obtained according to the present invention exhibits particularly high fluidity, a melt tension value and melt stretchability, and can be a useful resin in the field of sheets and film-like processed products. In addition, since it has sufficient melt viscoelasticity, it can be used as a blow molding material such as die well, drawdown resistance, etc., as a material with remarkably excellent processing stability as a foaming material, and blow molding and foaming processability with other thermoplastic resins. Can be a useful resin as a compounding material for imparting the following.

Hereinafter, the present invention will be described in more detail. In the present invention, examples of the styrene-based monomer forming the styrene-based compound unit (A) include styrene, α-methylstyrene, p-methylstyrene, and the like. Styrene is particularly preferable because it is inexpensive. . These styrene monomers can be used alone or in combination of two or more. The content of the styrene compound unit (A) is 100 to 40% by weight. Even when the properties of the copolymer are changed by copolymerization with other copolymerizable monomers, if it is less than 40% by weight, the melt fluidity changes and the rigidity of the molded product changes. For example, the basic properties of the styrene resin are lost.

Other monomers copolymerizable with styrene forming the copolymerizable compound unit (B) of the present invention include vinyl cyanide compounds such as acrylonitrile and methacrylonitrile, methyl methacrylate, and methacrylic acid. (Meth) acrylate monomers such as ethyl, methyl acrylate and ethyl acrylate, and α, β-ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic anhydride and fumaric acid, and phenyl Examples include imide monomers such as maleimide and cyclohexylmaleimide.

Particularly, in order to improve the oil resistance, acrylonitrile is copolymerized, and to improve the weather resistance, to adjust the glass transition temperature in a region where the practical range of the molded product is not narrowed, and to impart molding processability, it is necessary to use a general method. Chemical formula; CH ₂ ＣC (R ₁ ) CO
OR ₂ (wherein R ₁ is hydrogen or a methyl group, and R ₂ is an alkyl group having 1 to 8 carbon atoms) (meta)
It is desirable that a monomer composed of one or a combination of two or more acrylates be copolymerized and contained. These may be used alone or as a mixture of two or more. It is necessary that the content of the component (B) compound unit is not more than 60% by weight. If the content exceeds 60% by weight, the content of the component (A) compound unit decreases, and the basic characteristics are lost.

The styrenic copolymer of the present invention has the following chemical formula M (Acid ₁ ) _X (Acid ₂ ) _NX (where M is a cation valence) Is the metal of N and Aci
d ₁ is an α, β-ethylenically unsaturated carboxylic acid,
Acid ₂ is another carboxylic acid different from Acid ₁ . X (≠ 0, X <N) and N−X (≠ 0) are A
The number of moles of salt formed with respect to metal M of cid ₁ and Acid ₂ is shown. ) Must be copolymerized and contained as an essential component.

Examples of the metal constituting the above-mentioned metal complex salt of a reactive carboxylic acid include an alkaline earth metal and a metal forming an amphoteric oxide. Specific metal elements include beryllium, magnesium, calcium, strontium, barium, zinc, cadmium, aluminum, germanium, indium, silicon, tin, lead, antimony, bismuth and the like. Considering the solubility in the styrene monomer, magnesium, zinc and lead are preferred, and magnesium and zinc are more preferred in view of the toxicity of the metal.

Acid ₁ constituting component (C) of the present invention
Examples of the α, β-ethylenically unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, itaconic acid, fumaric acid, etc., and in consideration of the high copolymerization reactivity, acrylic acid and methacrylic acid are preferred. The content in the composite salt is 90 to 40 mol%, and in order to avoid the composite salt remaining unreacted in the resin, 90 to 60 mol%
Is more preferably in the range. In particular, when zinc or magnesium, which is a divalent metal, is used, since N in the above chemical formula is 2, X must be in the range of 1.8 to 0.8, and more preferably 1.8 to 1.2. Is preferred.

Acid _{2 in} component (C) of the present invention
Is, as other carboxylic acids different from Acid ₁ ,
Aromatic carboxylic acids such as benzoic acid, cinnamic acid, salicylic acid and coumaric acid, aldehydes or keto acids such as levulinic acid, acetoacetic acid, malonic acid and pyruvic acid, a series of aliphatic carboxylic acids, heterocyclic carboxylic acids and rosin Alicyclic carboxylic acids such as acids are exemplified.Aromatic carboxylic acids, aliphatic carboxylic acids, and alicyclic carboxylic acids have high solubility in styrene-based monomers with a small amount of use to form a complex salt. Are suitable. Other carboxylic acids are added to the complex salt in order to avoid the complex salt remaining unreacted in the resin.
Desirably, the content is 0 to 60 mol%, and more preferably 10 to 40 mol%.

In the styrenic copolymer of the present invention,
(A) Component compound unit and (B) component compound unit in total 1
It is necessary that the above-mentioned reactive carboxylic acid metal composite salt unit (C) is copolymerized and contained in an amount of 0.001 to 2 parts by weight per 00 parts by weight. In consideration of the viscosity of the polymerization system during the polymerization reaction from the viewpoint of productivity, sufficient copolymer viscoelasticity is imparted, and it is preferable that the copolymer is contained in a proportion of 0.01 to 1.5 parts by weight. If the amount is less than 0.001 part by weight, the effect of improving the melt tension value, die swell, etc. is low. If the amount exceeds 2 parts by weight, the viscosity in the reactor increases, the productivity decreases, the fluidity decreases, and the melt drawability is insufficient. I do.

The styrene copolymer in the present invention is:
It means those containing, in principle, the reactive carboxylic acid metal complex salt represented by the above chemical formula, but is composed of only stochastically existing other carboxylic acids and has low copolymerization reactivity or copolymerization reaction. A metal complex salt having no property may be contained as an unreacted residue in the resin, and such a salt is also included in the present invention.

The units derived from other carboxylic acids in the carboxylic acid metal complex salt contained as copolymerized or contained as unreacted residue are converted from metal cations at a temperature at which the resin melts and becomes fluid. It is presumed that dissociation, free movement in the resin, and repetition of attachment / detachment to other ionic cross-linking points enhance the melt fluidity of the resin and the effect of enhancing the melt stretchability. Even if the carboxylic acid metal complex salt corresponding to the unreacted residue is contained in the resin by kneading or the like after the production of the resin, it is difficult to sufficiently control the dispersion state, probably because of the melt flowability and melt drawing. The effect of enhancing the properties is not exhibited.

The styrenic copolymer of the present invention has sufficient melt viscoelastic properties as it is. However, by blending it with another thermoplastic resin, the melt tension value, die swell, drawdown resistance, etc. It is also possible to obtain a resin composition having the above-mentioned performance. Examples of other thermoplastic resins in this case include polyester resins, polycarbonate resins, polyamide resins, methacrylic resins, polyphenylene oxide resins, styrene resins, and the like.
In order to efficiently impart these properties with a small amount of addition, since it is desirable that both are in a compatible system or a partially compatible system, a polyphenylene oxide resin or a styrene resin is preferable, and a styrene resin is more preferable. .

The styrenic copolymer of the present invention comprises a high impact polystyrene (HIPS) resin containing rubber components such as polybutadiene rubber and styrene-butadiene copolymer rubber as dispersed particles, an ABS resin,
A rubber-modified styrene resin such as a BS resin may be used. In this case, the copolymer composition of the portion excluding the rubber component within the scope of the present invention can be used by being included in the present invention.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below. The styrenic copolymer of the present invention contains 100 to 40% by weight of a styrene-based compound unit, 0 to 60% by weight of another copolymerizable compound unit, and 100 parts by weight of a reactive carboxylic acid. The metal complex salt units are copolymerized at a ratio of 0.001 to 2 parts by weight. One preferred example of such a method for producing the copolymer of the present invention is a method in which a reactive carboxylic acid metal complex salt formed in advance is dissolved in a mixture with a styrene monomer or another copolymerizable monomer to form a radical. This is a bulk polymerization method for polymerization. This bulk polymerization method may be a batch type or a continuous type, but in particular, when producing a highly transparent copolymer, it is desirable to reduce the copolymer composition distribution of each component. It is preferred to use a completely mixed reactor.

The reactive carboxylic acid metal complex salt used in the method for producing a styrene-based copolymer of the present invention is prepared by dissolving in advance a raw material solution prepared by polymerization of a styrene-based monomer or the like to form a uniform colorless and transparent solution. Is desirable. Here, as an example of the method for preparing the reactive carboxylic acid metal complex salt, α, β-ethylenically unsaturated carboxylic acid and other carboxylic acids were dissolved in a general-purpose organic solvent such as methanol, and further dispersed in the organic solvent. A slurry of a metal oxide and a hydroxide in the same amount as the carboxylic acid functional group concentration is gradually added, and the reaction is carried out with stirring to obtain a reactive metal carboxylate complex as a colorless and transparent solution. When the used organic solvent is inappropriate in a polymerization reaction, a devolatilization step, or the like, it is replaced with a monomer component or the like, or is precipitated as a crystal.

As an example of the method for producing the styrenic copolymer of the present invention, the reactive metal complex carboxylate obtained by the above operation is mixed with a styrenic monomer or another copolymerizable monomer. Is sufficiently dissolved in a mixed solution of, and, if necessary, polybutadiene rubber or styrene-butadiene rubber is dissolved, and polymerization is performed in the presence or absence of a commonly used radical catalyst, a chain transfer agent, or the like. . The polymerization temperature can be determined in consideration of the fluidity and productivity of the styrene copolymer, the heat removal capability of the reactor, and the like. The conversion of the polymer discharged from the polymerization reactor to the monomer component is 40 to 80% by weight. Polymerization liquids in this range provide favorable melt viscoelastic properties. After the polymerization, to remove unreacted monomer, polymerization solvent, etc., perform the treatment under vacuum,
Obtain the desired styrenic copolymer.

In the method for producing a styrenic copolymer of the present invention, the above-mentioned bulk polymerization method is a desirable mode. However, the heat removal capability of the reactor used for the polymerization is taken into consideration, and the viscosity in the reactor is adjusted. For this purpose, a polymerization solvent may be added as necessary. Copolymers such as aromatic hydrocarbons such as benzene, toluene, xylene and ethylbenzene, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, aliphatic hydrocarbons such as hexane, and alicyclic hydrocarbons such as cyclohexane. In addition to a good solvent, a small amount of alcohol such as methanol for enhancing the solubility of the reactive carboxylic acid metal complex salt in the monomer mixture may be added as a polymerization solvent if a small amount is used. Solvents having a high coordination ability to metal ions and are difficult to remove in the devolatilization step after the completion of polymerization. It is desirable to use.

The styrenic copolymer of the present invention thus obtained can be blow-molded, extruded sheet,
Can be processed into foamed products, etc., if necessary, antioxidants,
Heat stabilizers, light stabilizers, flame retardants, nonionic surfactants,
Liquid paraffin, ethylene bis fatty acid amide, adipic acid, dibutyl or dioctyl ester of sebacic acid, higher fatty acid, metal salt of higher fatty acid, organic polysiloxane, etc. may be added as a lubricant.

[0030]

Next, the present invention will be described in more detail by way of examples, which should not be construed as limiting the present invention. In addition, the physical property test method in the Example of this invention is described below.

(1) Content of metal carboxylate complex salt Measured as the content of metal used by atomic absorption spectrometry,
Calculated. (2) Melt flow rate (MFR) Measured according to ASTM D-1238.

(3) Melt tension value and maximum melt stretching ratio: Using a capillary rheometer “Capillograph 1B type” manufactured by Toyo Seiki Co., Ltd., the melt tension value immediately before the thread-stretched resin was broken under the following conditions was measured. I do.
The value obtained by dividing the winding linear speed at that time by the extrusion speed was taken as the maximum melt draw ratio. <Measurement conditions>-Measurement temperature: 200 ° C-Barrel diameter: 9.55 mm-Capillary: L / D = 10/1 mm-Measuring unit: 60 cm from die-Extrusion speed: 10 mm / min constant-Winding line speed: 2 Changes continuously within a range of 200 m / min

(4) Sheet extrudability: The thickness unevenness of a 0.5 mm thick sheet extruded from a 30 mm extruder T die is measured. Goods within ± 5% are evaluated as good (especially excellent), and those with more than 5% are evaluated as poor. (5) Sheet formability: The sheet formed by the above method is formed into a cup-shaped container by vacuum forming, the thickness unevenness around the periphery (center of the body) is measured, and ± 1 from the average thickness.
Goods within 0% are rated as good (especially excellent are rated as good), and those with more than 0% are rated poor.

(6) Dicewell The measurement was performed under the following conditions using a capillary rheometer “Capillograph 1B” manufactured by Toyo Seiki. <Measurement conditions> Measurement temperature: 200 ° C. Barrel diameter: 9.55 mm Capillary: L / D = 10/1 mm Extrusion speed: 5 mm / min

(7) Drawdown resistance Using a die having a die diameter of 37 mm and a core diameter of 33 mm, under the conditions of a cylinder temperature of 220 ° C. and a parison weight of 300 g, a drawdown of the parison length immediately after injection and the parison length after 15 seconds. The ratio was calculated by the following equation to determine the drawdown resistance. <Evaluation conditions> Parison weight: 300 g Parison length immediately after injection: 40 cm Resin temperature: 220 ± 5 ° C. Drawdown ratio = L / L0 (L: parison length after 15 seconds, L0: immediately after injection) Parison length)

* Preparation of Reactive Carboxylic Acid Metal Complex Salt-1 A solution prepared by dissolving 300 g of methanol and 24.4 g of benzoic acid in 154.8 g of methacrylic acid is added. A mixture of 83 g of zinc oxide dispersed in 300 g of methanol is gradually added to this solution with stirring at room temperature. After completion of the addition, the mixture is stirred for 30 minutes as it is, and then 70 ± 5
Heat to ° C. and collect and dry the methanol. Bulk white crystals soluble in styrene are obtained. The reactive metal carboxylate complex obtained by this operation is represented by the following chemical formula. Zn (MAA) _1.8 (Bz) _0.2 (wherein, MMA represents methacryl and Bz represents benzoyl)

* Preparation of Reactive Carboxylic Acid Metal Complex Salt-2 A solution prepared by dissolving 57.6 g of caprylic acid in 300 g of methanol in 68.8 g of methacrylic acid and 57.6 g of acrylic acid is added. 40.3 g of magnesium oxide is gradually added to this solution while stirring at room temperature. After the addition, 30
Stir for about 10 minutes, then add 100 g of ethylbenzene
Is added. Thereafter, the mixture is heated to 70 ± 5 ° C. to recover methanol. By this operation, a transparent ethylbenzene solution containing 70% by weight of the reactive metal carboxylate complex represented by the following chemical formula is obtained. Mg (MAA) _0.8 (AA) _0.8 (Cap) _0.4 (where MAA is methacryl, AA is acrylic, Ca
p represents capryl)

Example 1 To 100 parts by weight of styrene, 0.1 part by weight of the above-described metal complex salt of reactive carboxylic acid-1 was added and completely dissolved, and 10 l of the mixed solution was placed in a complete mixing type polymerization vessel having an internal volume of 50 l. /
Feed continuously at a rate of hr. The polymerization temperature was 135 ° C., and the conversion of the styrene component in the polymer solution discharged from the polymerization vessel was 70%. 230 ° C. of this polymer solution
To a twin screw extruder heated to 20 mmH
g under reduced pressure to obtain a colorless and transparent styrene-based copolymer containing 0.14 parts by weight of the reactive carboxylic acid metal complex unit (C) per 100 parts by weight of the styrene unit (A). Table 1 shows the analytical values and physical properties of the obtained resin composition. Compared with Comparative Example 1 described later, the melt tension value (M · T), the maximum melt elongation ratio, and the melt flow rate (M
FR) and is excellent in sheet extrudability and sheet formability.

Examples 2 and 3 The same operation as in Example 1 was carried out except that the addition amount of the reactive metal carboxylate complex salt-1 was changed to 0.5 and 1.0 part by weight, respectively. The polymer was prepared. Reactive carboxylic acid metal complex salt units (C) were each added to 0.7
A colorless and transparent styrene-based copolymer containing 1,1.43 parts by weight was obtained. Table 1 shows the analytical values and physical properties of the obtained resin composition. Both are melt tension values (MT),
It has a high maximum melt draw ratio and a high melt flow rate (MFR) and is excellent in sheet extrudability and sheet formability. Example 2
About die well and drawdown resistance (L / L
Table 2 shows the analytical values of ( ₀ ).

Comparative Example 1 A colorless and transparent polystyrene resin was obtained in the same manner as in Example 1, except that the polymerization was carried out without adding the reactive metal carboxylate complex salt-1. Table 1 shows the analytical values and physical properties of the obtained resin composition. Although the maximum melt draw ratio and the melt flow rate (MFR) were high, the melt tension value (MT) was low, and both sheet extrudability and sheet formability were poor.

Comparative Example 2 A styrenic copolymer was prepared in the same manner as in Example 2 except that the metal complex salt of reactive carboxylic acid-1 was changed to zinc dimethacrylate. Zinc dimethacrylate was insoluble in styrene, and a cloudy copolymer was obtained. Table 1 shows the analytical values and physical properties of the obtained resin composition.
The analytical values of die well and drawdown resistance (L / L ₀ ) are shown in Table 2. Maximum melt draw ratio and melt flow rate (MFR) are high, but melt tension value (MT)
And both sheet extrudability and sheet formability were poor.

Comparative Example 3 Polymerization was carried out in the same manner as in Example 1 except that the amount of reactive metal complex complex 1 was changed to 3 parts by weight. The viscosity of the polymerization liquid in the reactor was significantly increased, and it was impossible to produce a styrene copolymer.

Example 4 0.5 part by weight of reactive metal complex carboxylate-1 and 0.1 part by weight of tertiary decyl mercaptan per 100 parts by weight of a mixture of 75% by weight of styrene and 25% by weight of acrylonitrile The mixed solution that has been added and completely dissolved is continuously supplied at a rate of 10 l / hr to a complete mixing type polymerization vessel having an internal volume of 50 l. The polymerization temperature was 145 ° C., and the conversion of the monomer component in the polymer solution discharged from the polymerization vessel was 70%.
%Met. This polymer solution was continuously supplied to a twin-screw extruder heated to 230 ° C., and treated under a reduced pressure of 20 mmHg to obtain a reactive carboxylic acid per 100 parts by weight of 73% by weight of styrene units and 27% by weight of acrylonitrile units. A colorless and transparent styrene-based copolymer containing 0.71 part by weight of an acid metal complex salt unit was obtained. Table 1 shows the analytical values and physical properties of the obtained resin composition. The analytical values of die well and drawdown resistance (L / L ₀ ) are shown in Table 2. It has high melt tension value (MT), maximum melt draw ratio, and melt flow rate (MFR), and is excellent in sheet extrudability and sheet formability.

Comparative Example 4 A styrene copolymer was obtained in the same manner as in Example 4 except that the reactive metal complex carboxylate-1 was not added to the monomer mixture solution. The composition of the copolymer was 73% by weight of styrene units and 27% by weight of acrylonitrile units. Table 1 shows the analytical values and physical properties of the obtained resin composition. The analytical values of die well and drawdown resistance (L / L ₀ ) are shown in Table 2. Although the maximum melt draw ratio and the melt flow rate (MFR) were high, the melt tension value (MT) was low, and both sheet extrudability and sheet formability were poor.

Example 5 80% by weight of styrene and 20% by weight of n-butyl acrylate
To 100 parts by weight of the above mixture, 0.71 part by weight of a 70% by weight solution of reactive metal complex carboxylate-2 in ethylbenzene was added, and the completely dissolved mixed solution was placed in a 50-liter complete mixing type polymerization vessel. Feed continuously at a rate of 10 l / hr. The polymerization temperature was 140 ° C., and the conversion of the monomer component in the polymer solution discharged from the polymerization vessel was 70%. This polymer solution is continuously supplied to a twin-screw extruder heated to 230 ° C., and is treated under a reduced pressure of 20 mmHg to obtain 100 parts by weight of 81% by weight of styrene units and 19% by weight of n-butyl acrylate units. A colorless and transparent styrene-based copolymer containing 0.71 part by weight of a reactive carboxylic acid metal complex unit per unit was obtained. Analysis value of the obtained resin composition,
The physical properties are shown in Table 1. Melt tension value (M
T), maximum melt draw ratio, melt flow rate (MFR)
And excellent in sheet extrudability and sheet formability.

Comparative Example 5 A styrene copolymer was obtained in the same manner as in Example 5, except that the reactive metal carboxylate complex salt-2 was not added to the monomer mixture solution. The composition of the copolymer was 81% by weight of styrene unit and 1 unit of n-butyl acrylate unit.
It was 9% by weight. Table 1 shows analytical values and physical properties of the obtained resin composition. Although the maximum melt draw ratio and the melt flow rate (MFR) were high, the melt tension value (MT) was low, and both sheet extrudability and sheet formability were poor.

Comparative Example 6 0.4 part by weight of zinc oxide and 0.2 part by weight of zinc acetate were dry-blended with respect to 100 parts by weight of a styrene-methacrylic acid copolymer having a methacrylic acid content of 2.0% by weight. With a twin-screw kneading extruder, the temperature is 260 ° C, and the feed rate is 15 kg / h
and water as the component (c) is added to the melting zone for 13 minutes.
The mixture was fed at a rate of 0 g / hr to carry out a neutralization reaction to prepare a styrene ionomer resin. A colorless and transparent styrene ionomer resin containing 1.37 parts by weight of zinc dimethacrylate unit was obtained. Table 1 shows analytical values and physical properties of the obtained resin composition. Melt tension value (MT)
Is high but the maximum melt draw ratio and melt flow rate (MF
R) was low and the sheet formability was poor.

Comparative Example 7 The styrene ionomer resin used in Comparative Example 6
0.5 parts by weight of zinc benzoate was added and kneaded at a temperature of 240 ° C. with a twin-screw kneading extruder to prepare a styrene ionomer resin composition. A cloudy and opaque resin composition resulting from zinc benzoate was obtained. Table 1 shows the analytical values and physical properties of the obtained resin composition. Although the melt tension value (MT) was high, the maximum melt draw ratio and the melt flow rate (MFR) were low, and the sheet formability was poor.

Examples 6 and 7 The styrenic copolymer obtained in Example 2 and a rubber-modified polystyrene resin (Estyrene H-7 manufactured by Nippon Steel Chemical Co., Ltd.)
8) were blended and kneaded at a weight ratio of 25/75 and 50/50, respectively, to prepare a resin composition. Table 2 shows the characteristics of the obtained resin composition containing the styrene copolymer.

Examples 8 and 9 The styrene copolymer obtained in Example 4 and ABS resin (Estyrene ABS-300, manufactured by Nippon Steel Chemical Co., Ltd.) were weighed 15/85 and 25/75, respectively. The resin composition was prepared by mixing and kneading at the same ratio. Table 2 shows the characteristics of the obtained resin composition containing the styrene copolymer.

Reference Examples 1 and 2 Table 2 shows the properties of the rubber-modified polystyrene resin and ABS resin used in Examples 6 to 9.

[0052]

[Table 1]

[0053]

[Table 2]

[0054]

The styrenic copolymer obtained by the method of the present invention exhibits high fluidity, a melt tension value and a melt drawability, and has remarkably excellent processing stability. In particular, blow molding materials, sheets and films It is a resin composition that is suitable as a material in the form of processed products and foamed products, and is also useful as a compounded resin material that is blended with other thermoplastic resins to give the melting properties required for blow molding. .

Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location C08F 220: 04) (C08F 212/06 220: 10 220: 04)

Claims (5)

[Claims] 1. The styrene compound unit (A) is 100 to 100%.
40% by weight, 0 to 60% by weight of the other copolymerizable compound unit (B), and 100 parts by weight of the total of (A) and (B), the following chemical formula (1) M (Acid ₁ ) _X (Acid ₂ ) _NX (1) (where M is a metal having a cation valence of N and Aci
d ₁ is an α, β-ethylenically unsaturated carboxylic acid,
Acid ₂ is another carboxylic acid different from Acid ₁ . X (≠ 0, <N) and N−X (≠ 0) are A
It represents the number of moles of salt formed with respect to metal M of cid ₁ and Acid ₂ . A) a styrene copolymer obtained by copolymerizing the reactive carboxylic acid metal complex unit (C) represented by the formula (1) in a ratio of 0.001 to 2 parts by weight. 2. The monomer forming the styrene-based compound unit (A) is styrene, and the other monomer forming the copolymerizable compound unit (B) is acrylonitrile or a general chemical formula; CH ₂ ＣC (R ₁ ) COOR ₂ (wherein, R ₁
Is hydrogen or a methyl group, and R ₂ is an alkyl group having 1 to 8 carbon atoms. 2. The styrenic copolymer according to claim 1, comprising one or a combination of two or more (meth) acrylates represented by the formula (1). 3. The reactive carboxylic acid metal complex salt unit (C) represented by the chemical formula (1), wherein M is at least one metal selected from zinc or magnesium (N = 2), and Acid ₁
Is at least one selected from acrylic acid or methacrylic acid, and X is in the range of 1.8 to 0.8, and Acid ₂ is selected from aromatic carboxylic acids, aliphatic carboxylic acids, and alicyclic carboxylic acids. One or two
The styrenic copolymer according to claim 1, wherein the styrenic copolymer comprises at least one species. 4. A compound of the following chemical formula M (Acid ₁ ) _X (Acid ₂ ) based on 100 parts by weight of a styrenic monomer alone or a mixture thereof with at least one other monomer copolymerizable therewith. ) _NX (where M is a metal having a cation valency of N and Ac
id ₁ is an α, β-ethylenically unsaturated carboxylic acid,
Acid ₂ is another carboxylic acid different from Acid ₁ . X (≠ 0, X <N) and NX (≠ 0) represent the number of moles of the salt M of Acid ₁ and Acid _{2 with} the metal M, respectively. A method for producing a styrene-based copolymer, comprising dissolving the reactive metal complex carboxylate represented by the formula (1) in a ratio of 0.001 to 2 parts by weight and subjecting to radical polymerization. 5. The metal complex salt of a reactive carboxylic acid comprises 90 to 40 mol of at least one α, β-ethylenically unsaturated carboxylic acid selected from acrylic acid or methacrylic acid.
% Of one or more carboxylic acids selected from aromatic carboxylic acids, aliphatic carboxylic acids, and alicyclic carboxylic acids, and 10 to 60 mol% of one or more metals selected from zinc or magnesium. 5. The method for producing a styrene-based copolymer according to claim 4, wherein the styrene-based copolymer is reacted with a hydroxide.