JPH0881645A - Thermoplastic resin composition for electrostatic coating - Google Patents

Abstract

PURPOSE: To obtain a thermoplastic resin composition having excellent electrostatic coating properties, resistances to chemicals and also high impact resistance and heat resistance in a practical level, useful as interior or exterior parts of a car, etc., by blending a rubber-modified styrene-based resin with a specific compound having an erythritol structure, etc. CONSTITUTION: This composition is composed of a total 100 pts.wt. of (A) 85-99 pts.wt. of a rubber-modified styrene-based resin and (B) 15-1 pts.wt. of a styrene-based resin containing 1-20wt.% OH-group containing vinyl-based monomer as a copolymerization component, blended with (C) 0.01-5.0 pts.wt. of a phosphite-based compound expressed by formula I (R is a 1-30C alkyl or 2,4-di-t-butylphenyl) (e.g. cyclic neopentanetetraylbis(2,4-dz-t-butylphenyl) phosphite) and (D) 0.01-5.0 pts.wt. of a polyoxyethylene alkylphenyl ether [e.g. expressed by formula II (R' is an alkyl; (n) is 4-16), concretely, polyoxyethylene dodecylphenyl ether, etc.].

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin composition for electrostatic coating, which is used as a molding material having excellent electrostatic coating properties.

[0002]

2. Description of the Related Art Rubber-modified styrenic resin is a resin with high insulation properties, and electrostatic coating was not possible. However, by applying a conductive surfactant to the surface of the molded product, surface specific resistance can be reduced. It has been lowered and electrostatic coating can be performed.
However, depending on the shape of the molded product, since the coating is applied to the deep part of the molded product, it is necessary to apply the conductive surfactant in a large excess, and as a result, a coating failure phenomenon (a cissing phenomenon of the coating film) occurs.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art, and an object thereof is to provide a thermoplastic resin composition having excellent electrostatic coating properties.

[0004]

According to the present invention, (A) 85 to 99 parts by weight of a rubber-modified styrene resin and (B) a hydroxyl group-containing vinyl monomer as a copolymerization component are contained in an amount of 1 to 20% by weight.
With respect to the total amount of 100 parts by weight of 15 to 1 parts by weight of the contained styrene-based resin (hereinafter also referred to as “hydroxyl group-containing styrene-based resin”), (C) the phosphite-based compound represented by the following general formula (I). 01-5.0 parts by weight and (D) polyoxyethylene alkylphenyl ether 0.01-5.
The present invention provides a thermoplastic resin composition for electrostatic coating containing 0 part by weight.

[0005]

Embedded image

[In the general formula (I), R is a carbon number of 1 to 30.
Is an alkyl group or a 2,4-di-t-butylphenyl group. ]

The rubber-modified styrene-based resin (A) used in the composition of the present invention is a rubber-modified styrene-based polymer obtained by graft-polymerizing a styrene-based monomer onto a rubber-like polymer, or a rubber-modified styrene-based polymer. It is a mixture of a vinyl-based polymer and a styrene-based polymer (not modified with a rubber), and a rubber-based polymer is contained in the styrene-based polymer for the purpose of obtaining a high impact resistance. The content may be a simple mechanical blending method, but in order to obtain good compatibility, so-called graft copolymerization is carried out by graft-copolymerizing a styrene-based monomer or the like in the presence of a rubbery polymer. The one obtained by the polymerization method is more preferable. It is also preferable to use a rubber-modified styrene-based polymer (graft copolymer) obtained by this method and a so-called graft-blend method in which a styrene-based polymer obtained by a separate method is mixed.

Examples of the rubbery polymer include polybutadiene rubber, diene rubber such as styrene-butadiene rubber, hydrogenated styrene-butadiene rubber, acrylic copolymer, ethylene-propylene- (diene). ) -Based copolymers, silicone-based rubbers, chlorinated polyethylenes, polyurethanes and the like, but polybutadiene rubbers are preferably used. On the other hand, examples of the styrene-based monomer include styrene, α-methylstyrene, bromostyrene, and the like. Among these, styrene is optimally used.

If necessary, it is possible to copolymerize the styrene-based monomer with another monomer copolymerizable with these styrene-based monomers. Examples of the other monomer include acrylonitrile, methacrylonitrile, methyl methacrylate, N-phenylmaleimide, N-cyclohexylmaleimide and the like. In the rubber-modified styrenic resin (A), impact resistance is difficult to develop when a styrenic monomer is used alone, so it is preferable to copolymerize acrylonitrile.

The amount of the component (A) used is 85 to 99 parts by weight, preferably 90 to 95 parts by weight, more preferably 93 to 95 parts by weight, and 85 parts by weight in the components (A) to (B). If it is less than 100 parts by weight, the impact resistance is inferior, while if it exceeds 99 parts by weight, the moldability and heat resistance are inferior.

The component (A) is obtained by emulsion polymerization using a non-linear emulsifier, and / or the residual content of organic acid and / or metal salt derived from the emulsifier is 0.5% by weight. The following are preferable. In order to reduce the residual content to 0.5% by weight or less, means such as a method of reducing the content to 0.5% by weight or less by washing with water at the time of recovering the resin after emulsion polymerization may be used. If the residual content exceeds 0.5% by weight, electrostatic coating becomes inferior, which is not preferable.

Specific examples of the rubber-modified styrene resin (A) thus obtained include acrylonitrile-butadiene-styrene resin (ABS resin), acrylonitrile-ethylene / propylene-styrene resin (AES resin), methyl methacrylate. -Butadiene-styrene resin (MBS resin), acrylonitrile-butadiene-methyl methacrylate-styrene resin, acrylonitrile-n
-Butyl acrylate-styrene resin (AAS resin),
Rubber modified polystyrene (high impact polystyrene;
HIPS), α-methylstyrene and / or heat-resistant rubber-modified styrene-based resin using N-phenylmaleimide.

The rubber-modified styrene resin (A) used in the present invention is produced by emulsion polymerization, solution polymerization, suspension polymerization or the like. At this time, as the polymerization initiator, molecular weight modifier, dispersant, solvent, etc. used in the polymerization, those usually used in these polymerization methods can be used as they are. (A) As a preferred method for producing the rubber-modified styrene resin, a monomer and an additional non-linear emulsifier, a monomer and a polymerization initiator are added in the presence of a rubbery polymer obtained by emulsion polymerization. Polymerization temperature is generally 30 to 150 ° C., polymerization time is 1 to 15 hours, and polymerization pressure is −
Graft copolymer obtained by graft copolymerization under the condition of 1.0 to 5.0 kg / cm ² (including ungrafted styrene polymer) and styrene polymer obtained by emulsion polymerization or solution polymerization It is prepared by mixing with a polymer.

Next, the (B) hydroxyl group-containing styrene resin is obtained by copolymerizing a hydroxyl group-containing vinyl monomer during the polymerization of the same styrene monomer (including other monomers) as described above. can get. Here, the hydroxyl group-containing vinyl monomer is a compound having at least one unsaturated bond (double bond or triple bond) and containing a hydroxyl group. Typical examples thereof include an alcohol having a double bond, an alcohol having a triple bond, an ester of a monovalent or divalent unsaturated carboxylic acid and an unsubstituted dihydric alcohol, and an unsubstituted trivalent unsaturated carboxylic acid. Examples thereof include esters with polyhydric alcohols, esters with unsubstituted tetrahydric alcohols, and esters with unsubstituted pentavalent or higher alcohols.

Of the hydroxyl group-containing vinyl monomers used in the present invention, preferred representative examples are 3-hydroxy-1-propane, 4-hydroxy-1-butene and cis-4-hydroxy-2-. Butene, trans-4-hydroxy-2-butene, 3-hydroxy-2-methyl-1
-Propene, cis-5-hydroxy-2-pentene, trans-5-hydroxy-2-pentene, cis-1,4
-Dihydroxy-2-butene, trans-1,4-dihydroxy-2-butene, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 2-hydroxyethyl crotonate,
2,3,4,5,6-pentahydroxyhexyl acrylate, 2,3,4,5,6-pentahydroxyhexyl methacrylate, 2,3,4,5-tetrahydroxypentyl acrylate, 2,3,4,5 -Tetrahydroxypentyl methacrylate and the like. Among these, it is preferable to use 2-hydroxyethyl methacrylate. These hydroxyl group-containing vinyl monomers can be used alone or in combination of two or more.

(B) The amount of the hydroxyl group-containing vinyl monomer in the hydroxyl group-containing styrene resin is 1 to 20% by weight, preferably 5 to 15% by weight, more preferably 8 to 12% by weight, If it is less than 1% by weight, the electrostatic coating property is poor, while if it exceeds 20% by weight, the thermal stability is poor.

The (B) hydroxyl group-containing styrene resin used in the present invention is produced by emulsion polymerization, solution polymerization, suspension polymerization or the like. Further, at this time, as the polymerization initiator, molecular weight regulator, emulsifier (preferably non-linear emulsifier), dispersant, solvent, etc. used for the polymerization, those usually used in these polymerization methods are used as they are. It is possible. (B) As a preferable method for producing the hydroxyl group-containing styrene resin, a styrene monomer (including other monomer), a hydroxyl group-containing vinyl monomer, an emulsifier and a polymerization initiator are used, and the polymerization temperature is generally 30. ~ 150 ° C, polymerization time 1 to 15 hours, polymerization pressure -1.0 to 5.0 kg / cm ²
Copolymerize under the conditions of.

The amount of the component (B) used is 15 to 1 part by weight, preferably 10 to 2 parts by weight, more preferably 7 to 3 parts by weight in the components (A) to (B). If the amount of the component (B) used is less than 1 part by weight, the electrostatic coating property will be poor, while if it exceeds 15 parts by weight, the thermal stability and impact resistance will be poor.

Next, (C) used in the composition of the present invention.
The phosphite compound is a compound having an erythritol structure represented by the general formula (I). In general formula (I), R is an alkyl group having 1 to 30 carbon atoms or a 2,4-di-t-butylphenyl group. Specific examples of the (C) phosphite compound include dilauryl pentaerythritol diphosphite, distearyl pentaerythritol phosphite, cyclic neopentanetetraylbis (2,4-di-t-butylphenyl) phosphite, and the like. Is mentioned. Among these, cyclic neopentanetetraylbis (2,4-di-t
-Butylphenyl) phosphite is preferred.

The amount of the (C) phosphite compound used is
With respect to 100 parts by weight of the total amount of the components (A) and (B),
0.01-5.0 parts by weight, preferably 0.01-2.0
Parts by weight, more preferably 0.02 to 1.0 parts by weight. If the amount of the component (C) used is less than 0.01 parts by weight, the electrostatic coating property is poor, while if it exceeds 5.0 parts by weight, the heat resistance is poor.

Next, the (D) polyoxyethylene alkylphenyl ether used in the present invention is represented by the following general formula (I
It is represented by I).

[0022]

[Chemical 3]

(In the formula, R'represents an alkyl group, and n is 4
~ 16. In the general formula (II), R'is an alkyl group, preferably a linear alkyl group, and more preferably 7 to 1 carbon atoms.
7 is a linear alkyl group, and the chain length n of the polyoxyethylene chain is 1 or more, preferably 6 to 10. Specific examples of (D) polyoxyethylene alkyl phenyl ether include polyoxyethylene dodecyl phenyl ether. The amount of component (D) used is 0.01 to 5.0 parts by weight, preferably 0.01 to 5.0 parts by weight, based on 100 parts by weight of the total amount of components (A) and (B).
2.0 parts by weight, more preferably 0.05 to 1.0 parts by weight. If the amount of component (D) used is less than 0.01 parts by weight, the electrostatic coating property is poor, while if it exceeds 5.0 parts by weight, heat resistance and thermal stability are poor.

Various compounding agents may be added to the composition of the present invention. Examples of these compounding agents include 2,6-di-t-butyl-4-methylphenol,
2- (1-methylcyclohexyl) -4,6-dimethylphenol, 2,2-methylene-bis- (4-ethyl-
6-t-butylphenol), 4,4'-thiobis-
(6-t-butyl-3-methylphenol), dilaurylthiodipropionate, tris (di-nonylphenyl) phosphite, wax and other antioxidants; p-t
-UV absorbers such as butyl phenyl salicylate, 2,2'-dihydroxy-4-methoxybenzophenone and 2- (2'-hydroxy-4'-n-octoxyphenyl) benzotriazole; paraffin wax, stearic acid, hardened oil , Stearamide, methylenebis stearamide, n-butyl stearate, ketone wax,
Examples thereof include lubricants such as octyl alcohol, lauryl alcohol and hydroxystearic acid triglyceride; antistatic agents such as stearoamidopropyldimethyl-β-hydroxyethylammonium nitrate; pigments and the like.

The composition of the present invention can be obtained by mixing the components (A) to (D) using a conventional mixing method. For example, each component is mixed with a mixer, and then melt-kneaded with an extruder at 150 to 240 ° C. to granulate.
Furthermore, each component can be simply melt-kneaded and molded in a molding machine.

[0026]

EXAMPLES The present invention will be described more specifically below with reference to examples. In the examples, parts and% are based on weight unless otherwise specified. The evaluation of physical properties is as follows. Izod impact strength ASTM D256 (1/4 ", 23 ° C, notched) Heat distortion temperature ASTM D648 (18.6 kg / cm ² )

Electrostatic coating property (coating appearance ) Test piece; thickness 3.2 mm × 7 mm × 15 mm Conductive primer; Plastic conductive agent NC [manufactured by Cashew Co., Ltd.] 0.75% isopropyl alcohol solution Paint used; Retan PG60 ( Kai) [Kansai Paint Co., Ltd.
Manufacturing] Film thickness = 25 μm The evaluation was as follows. ○: There are no defects such as suction and cissing. X: There are defects such as suction and cissing. Thermal stability test piece; thickness 2 mm, diameter 100 mm, pin gate molding temperature; 280 ° C. Evaluation was as follows. ○: No silver streak is observed. X: Silver streak occurs.

Example 1, Comparative Examples 1 to 6 Preparation of Component (A) The following components were used as the component (A). Rubber-modified styrene resin (a-1); 40 parts of polybutadiene rubber latex in terms of solid content, ion-exchanged water 65 in a reactor equipped with a reflux condenser, a thermometer and a stirrer.
Parts, 0.35 parts of rosin acid soap, 15 parts of styrene and 5 parts of acrylonitrile, and then 0.2 parts of sodium pyrophosphate, 0.01 parts of ferrous sulfate heptahydrate and 0.4 parts of glucose are ionized. It was added to a solution dissolved in 20 parts of exchanged water.

Then, 0.07 part of cumene hydroperoxide was added to start the polymerization, and after 1 hour of polymerization, 45 parts of ion-exchanged water and 0.7 part of rosin acid soap were added,
30 parts of styrene, 10 parts of acrylonitrile and 0.01 part of cumene hydroperoxide were continuously added over 2 hours, and the reaction was completed by further polymerizing for 1 hour. Sulfuric acid was added to the obtained copolymer latex for coagulation, and the content of residual organic acid and / or metal salt was 0.
It was washed with water and dried to 5% or less to obtain a rubber-modified styrene resin (a-1).

Styrenic resin (a-2); reflux condenser,
In a reactor equipped with a thermometer and a stirrer, ion-exchanged water 2
50 parts, potassium rosinate 3.0 parts, styrene 70 parts,
Add 30 parts acrylonitrile and 0.1 parts t-dodecyl mercaptan, then 0.05 parts sodium ethylenediaminetetraacetate, 0.002 parts ferrous sulfate heptahydrate and 0.1 parts sodium formaldehyde sulfoxylate.
Parts were added to a solution dissolved in 8 parts of deionized water. Then, 0.1 part of diisopropylbenzene hydroperoxide was added to start the polymerization, and the polymerization was completed for about 1 hour to complete the reaction. Sulfuric acid was added to the obtained copolymer latex for coagulation, washed with water until the content of residual organic acid and / or metal salt was 0.5% or less, and dried to obtain styrene resin (a-2). It was

Preparation of Component (B) The following was used as the component (B). Hydroxyl group-containing styrene-based resin; ion-exchanged water 250 parts, potassium rosinate 3.0 parts, styrene 70 parts, acrylonitrile 20 parts, 2-hydroxyethyl methacrylate 10 in a reactor equipped with a reflux condenser, a thermometer and a stirrer.
And 0.1 part of t-dodecyl mercaptan are added, and then 0.05 part of sodium ethylenediaminetetraacetate, 0.002 part of ferrous sulfate heptahydrate and 0.1 part of sodium formaldehyde sulfoxylate are added to ion-exchanged water. It was added to the solution dissolved in 8 parts. Then, 0.1 part of diisopropylbenzene hydroperoxide was added to start the polymerization, and the polymerization was completed for about 1 hour to complete the reaction. Sulfuric acid was added to the obtained copolymer latex for coagulation, washed with water until the content of residual organic acid and / or metal salt was 0.5% or less, and dried to obtain a hydroxyl group-containing styrene resin.

Preparation of Component (C) As the component (C), cyclic pentanetetraylbis (2,4-di-t-butylphenyl) phosphite [MARK PEP-24G manufactured by Asahi Denka Co., Ltd.] is used. Using. Preparation of component (D) As component (D), polyoxyethylene dodecyl phenyl ether [Kao (Emulgen 910, manufactured by Kao Corporation) was used.

Production of Thermoplastic Resin Composition for Electrostatic Coating Each component shown in Table 1 was melted and kneaded at a temperature of 190 to 240 ° C. using an extruder having an inner diameter of 50 mm to prepare pellets. The obtained pellets were molded at a molding temperature of 200 to 240 ° C. using a 50 oz injection molding machine to prepare test pieces, and their physical properties were evaluated. The results are shown in Table 1.

[0034]

[Table 1]

As is apparent from Table 1, the composition of the present invention of Example 1 has been obtained as the object of the present invention. On the other hand, the compositions of Comparative Examples 1 to 3 are compositions lacking any of the essential components (B) to (D) of the present invention and have poor electrostatic coatability. Further, the compositions of Comparative Examples 4 to 6 are examples in which the amount of any of the components (B) to (D), which is an essential component of the present invention, exceeds the range of the present invention,
Poor impact resistance, heat resistance or thermal stability.

[0036]

EFFECT OF THE INVENTION The thermoplastic resin composition for electrostatic coating of the present invention has excellent electrostatic coating properties and chemical resistance, and also has practically high level of impact resistance and heat resistance. . Therefore,
INDUSTRIAL APPLICABILITY The thermoplastic resin composition for electrostatic coating of the present invention can be used for automobile interior and exterior parts, housing materials for household appliances, structural materials, and the like, and is a practically excellent material, and has industrial significance. Extremely large.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area C08L 25:08 71:12)

Claims (1)

[Claims] 1. A rubber-modified styrenic resin 85-9
Styrene resin 1 containing 9 parts by weight and (B) a hydroxyl group-containing vinyl monomer as a copolymerization component in an amount of 1 to 20% by weight.
(C) 0.01 phosphite compound represented by the following general formula (I) per 100 parts by weight of the total amount of 5 to 1 parts by weight.
To 5.0 parts by weight and 0.01 to 5.0 parts by weight of (D) polyoxyethylene alkylphenyl ether. Embedded image [In the general formula (I), R represents an alkyl group having 1 to 30 carbon atoms or a 2,4-di-t-butylphenyl group. ]