JPH02191616A - Impact-resistant resin material for molding - Google Patents

Abstract

PURPOSE:To obtain a molding material for coated parts of interior automotive trim, having excellent urethane coating adhesiveness (adhesivity) by blending a specific styrene-based impactresistant resin material with an unsaturated carboxylic acid (anhydride) and an organic peroxide in a specific ratio and kneading in a molten state. CONSTITUTION:(A) 100 pts.wt. styrene-based impact-resistant resin material prepared by grafting a styrene monomer onto butadiene rubber containing at least 50wt.% butadiene is blended with (B) 0.1-3.0 pts.wt. unsaturated carboxylic acid (anhydride) [e.g. (meth)acrylic acid] and (C) 0.01-0.5 pt.wt. organic peroxide (e.g. t-butyl peroxybanzoate) and kneaded in a molten state to give the aimed material.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to impact-resistant resin materials for molding, and in particular to automobiles that use inexpensive styrene-based impact-resistant resin materials and have excellent urethane paint adhesion (adhesion). The present invention relates to molding materials for interior painted parts.

(Background Art) Conventionally, ABS resin, PP resin, PC resin, Noryl (modified PP0) resin, etc. have been known as molding materials for automobile parts to be painted, especially interior parts. ABS resin and PP resin are commonly used as inexpensive materials.

However, in order to ensure the adhesion of urethane coating to PP resin, a brimer was required, which was disadvantageous in terms of cost, and even with A and BS resins, it can be said that they are not necessarily cheap. It wasn't something.

In addition, as a cheaper molding material, there is HIPS material, that is, a styrene-based impact-resistant resin material, which is used in large quantities as a material for home appliance parts, but it is used for automobile parts because of its heat resistance,
It was not used at all because it had three problems: urethane paint adhesion and light resistance.

However, with regard to heat resistance, a separate solution has been found, and even with light resistance, light resistance is not necessarily required if automotive parts are to be painted. Therefore, if the adhesion of urethane coating is improved, such HIPS materials can be used as paint parts materials for automobiles.

In addition, styrene-maleic anhydride copolymer materials are available as styrene-based resin materials with excellent urethane paint adhesion on the market, but they do not have a cost advantage over ABS resins. The reality is that it is not used as a material for automotive interior paint parts.

By the way, JP-A-60-13837 discloses (
a) A method of graft polymerizing a vinyl compound having a polar group to a styrene polymer, (b) A method of copolymerizing styrene and a vinyl compound, (C) A method of blending a substance with adhesive properties into a styrene polymer. However, all of these methods require new processes and are impractical due to equipment investment, and as materials for automobile parts, they are less expensive in terms of material cost than ABS resin materials. There are also inherent problems such as a lack of superiority.

In addition, the above-mentioned publication discloses that impact-resistant resin (HIPS material) is produced by melt-kneading impact-resistant resin as a styrenic polymer and vinyl compound such as acrylic acid in the presence of an organic peroxide. ), but in such a method, a crosslinking reaction simultaneously proceeds in the impact-resistant resin due to the radicals of the organic peroxide used, and the modified copolymer The physical properties, appearance, moldability, and
It has been revealed that it is difficult to employ such a method because the compatibility etc. are significantly deteriorated.

(Problem to be solved) Here, the present invention aims to provide a material that is cheaper than the currently used ABS resin material as a molding material for automobile (interior) parts to be painted. It also maintains or improves the impact value and heat resistance of paint parts materials for automobiles, as well as adhesion and
The purpose is to improve various performances such as printability, appearance, and moldability, and in particular to provide a styrene-based impact-resistant resin molding material with improved adhesion to urethane coating.

(Solution Means) In short, the present invention was developed as a result of various studies on modification methods by melt-kneading styrene-based impact-resistant resins, vinyl compounds, and organic peroxides, which had been denied in the past. It was completed based on the knowledge that with a specific composition of ingredients, it is possible to obtain excellent effects that can solve all of the above problems, and its gist is that at least butadiene is 100 of a styrenic impact-resistant resin material obtained by graft polymerizing a styrene monomer to a butadiene rubber containing 50% by weight.
0.1-3.0 parts by weight of unsaturated carboxylic acid or its anhydride and 0.01-0 parts by weight of organic peroxide, based on parts by weight.
．． There is an impact-resistant resin material for molding obtained by blending 5 parts by weight and melting and kneading.

(Specific Structure) By the way, the styrene-based impact resistant resin material that is the base of the impact resistant resin material for molding produced according to the present invention is mainly composed of butadiene containing at least 50% by weight of butadiene. It is made by graft polymerizing a styrene monomer to a butadiene rubber as a component, and generally, those having an IZOD impact strength of 5 or more are used. The butadiene rubber used here is butadiene homopolymer rubber (BR).
There are rubbers made by copolymerizing butadiene with a small amount of acrylonitrile (NBR), and rubbers made by randomly or block copolymerizing styrene with butadiene (SBR). Usually, this butadiene-based rubber is contained in a proportion of 5 parts by weight or more. , 100 parts by weight of styrenic monomer are graft polymerized. In addition, such styrene-based impact-resistant resin materials are HIPS (high 1
These materials are known as mpact pol, ystyrene) materials and are also commercially available, and such commercially available materials are appropriately used in the present invention.

The styrene monomers to be graft-polymerized to the butadiene rubber include styrene, α-methylstyrene, methylstyrene, dimethylstyrene, trimethylstyrene, α-ethylstyrene, diethylstyrene,
Isopropylstyrene, butylstyrene, hexylstyrene, cyclohexylstyrene, decylstyrene, benzylstyrene, chloromethylstyrene, ethoxymethylstyrene, methoxystyrene, dimethoxystyrene, chlorstyrene, dichlorostyrene, trichlorstyrene, tetrachlorostyrene, pentachlor Examples include styrene, bromustyrene, dibromostyrene, vinylbenzoic acid, vinylbenzoic acid methyl ester, and styrene and methylstyrene are particularly preferably used.

The unsaturated carboxylic acid or its anhydride blended into such a styrene-based impact-resistant resin material is a radically polymerizable vinyl compound having a carboxyl group or its anhydride group, and generally has the following formula: : % formula % (R and Rz are hydrogen, alkyl group, aryl group, CHt COOH-CHICH=CHCHO, respectively)
,CH! C0OR* (R is a group having 1 to 6 carbon atoms)], more specifically, for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, sorbic acid, cinnamon Acids include citraconic acid, mesaconic acid, maleic acid, fumaric acid, ethacrylic acid, maleic anhydride, itaconic anhydride, and the like.

In addition, the organic peroxide blended into the styrenic impact-resistant resin material along with the unsaturated carboxylic acid or its anhydride has an -o-o- bond and is thermally decomposed at a relatively low temperature. and/or react with reducing substances7 and 2
．． Any substance that easily generates free radicals may be used, particularly preferably one having a decomposition temperature of 50°C for a half-life/10 hours as shown below.
The above substances are advantageously used.

For example, t-butyl peroxybenzoate, n-butyl-4,4-bis(t-butylperoxy)valerate, diam-butyl diveroxyisophthalate, methyl ethyl ketone peroxide, dicumyl peroxide, 2,5-dimethyl -2,5-di(t-butylperoxy)hexane, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, t-butylcumyl peroxide, di-isopropylbenzene hydroperoxide,・L-butyl peroxide, P-menthane hydroperoxide, 2゜5-dimethyl-2,
5-di(t-butylperoxy)hexyne-3,l,1
, 3.3-tetramethylbutyl hydroperoxide, 2.5-dimethylhexane 2.5-sibide lobaroxide, cumene hydroperoxide, L-butyl hydroperoxide, t-hexyl peroxyneohexanoate, t- Butyl peroxyneohexanoate, 2,4-dichlorobenzoyl peroxide, t
-hexyl peroxyvivalate, t-butylperoxyvivalate, 3,5.5-trimethylhexanoyl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, cumyl peroxyoctoate, succinic acid peroxide,
Acetyl peroxide, L-butyl peroxide (2-
ethylhexanony)), m-) ruyl peroxide, benzoyl peroxide, t-butylperoxyisobuty [/-t, 1. l-bis(t-butylperoxy')3.3.5-trimethylcyclohexane, 1.1-
Bis(1-butylperoxy)cyclohexane, L-butylperoxymaleic acid, L-butylperoxylaurate, mu-butylperoxy 3,5.51-limethyl-sanoate, cyclohexanone peroxide,
t-Butylperoxyallyl carbonate, 1-butylperoxyisopropyl carbonate, 2゜5-dimethyl-2,5-di(benzoylperoxy)hexane, 2
, 2-bis(t-butylperoxy)octane, t-butylbaroxyacetate, 2,2-bis(t-butylperoxy)butane, etc. are advantageously used in the present invention.

In the present invention, the above-mentioned unsaturated carboxylic acid or its anhydride and organic peroxide are each 0.1 to 3 parts by weight per 100 parts by weight of the above-mentioned styrenic impact-resistant resin material. .0 part by weight and 0.01 to 0.5 part by weight, and this improves the physical properties (heat resistance, impact resistance), appearance, moldability, etc. of the resin, which have been considered problems in the past. This made it possible to improve the adhesion (adhesiveness), paintability, and printability of urethane coatings without causing the problem of significant deterioration.

On the other hand, if the amount of unsaturated carboxylic acid or its anhydride is too large, exceeding 3.0 parts by weight, the appearance will deteriorate and physical properties such as impact resistance will deteriorate. Moreover, if the amount is too small, the adhesiveness of the urethane coating will decrease, making it impossible to achieve the intended purpose. In addition, since organic peroxides act as catalysts for graft polymerization of saturated carboxylic acids or their anhydrides to styrene-based impact-resistant resin materials, if the amount used becomes too small,
It is difficult to effectively carry out graft polymerization of a monomer consisting of such an unsaturated carboxylic acid or its anhydride, and therefore to achieve the intended purpose; Such a large amount deteriorates the appearance of the urethane coating, making it difficult to obtain a product of good quality.

By the way, the present invention obtains a molding material by blending a specific proportion of an unsaturated carboxylic acid or its anhydride and an organic peroxide with a styrenic impact-resistant resin material and melt-kneading the mixture as described above. However, through this melt-kneading, the unsaturated carboxylic acid or its anhydride is graft-polymerized onto the styrene-based impact-resistant resin material by the action of the organic peroxide. We were able to achieve such excellent results.

For this melt-kneading, a conventionally known method is appropriately selected, such as a Panbury mixer, a kneader,
In addition to the method of melt-kneading using a mixer such as a roll mill or screw extruder, it is possible to obtain a uniform layer by tri-blending in advance using a mixer such as a Henschel mixer and further melt-kneading the resulting mixture. It is possible to adopt a method using a mixture.

It should be noted that resin molded products, especially resin materials for molding automotive interior parts, always undergo a color toning process, that is, a material coloring process using pigments, etc., even if they are for painted parts. This can be carried out advantageously in this color toning process, thereby improving the adhesion, paintability, and printability of the material, and maintaining or improving physical properties such as heat resistance and impact resistance. As a result, the styrenic impact-resistant resin material can be effectively modified, and the increase in material costs can be effectively suppressed or prevented.

Further, by such a melt-kneading operation, the impact-resistant resin material for molding according to the present invention is generally obtained in the form of a molding raw material such as a pellet (toned pellet), and subsequently molded products such as automobile interior parts. This results in a shape that is easy to handle in the molding process to obtain this.

(Examples) In order to clarify the present invention more specifically, Examples of the present invention are shown below, but the present invention is not limited in any way by the description of such Examples. teeth,
It goes without saying.

In addition to the detailed explanation of the present invention and the following examples, the present invention may be modified in various ways based on the knowledge of those skilled in the art without departing from the spirit of the present invention. It should be understood that the present invention may be implemented in a different manner.

First, as a styrene-based impact-resistant resin material, HIPS is made by graft polymerizing 88 parts by weight of styrene to 12 parts by weight of styrene-butadiene random copolymer rubber (SBR) with a styrene content of 25% by weight. Using materials,
To 100 parts by weight of the vinyl compound (maleic anhydride or itaconic anhydride) and organic peroxide [2,5-dimethyl-2,5-di(
t-butylperoxy)hexyne-3] was pre-triblended using a Henschel mixer, and then a 30uφ 2
Using a shaft extrusion machine, the mixture was melt-kneaded under conditions of 200°C x 1 minute (average residence time) to obtain various pellets for molding.

The various molding pellets obtained were heated to 90°C.
After pre-drying at a temperature of 3 hours, test pieces specified in JIS-6871 were produced using an injection molding machine. Further, in this molding operation, the moldability was evaluated based on the flowability of the materials, and it was found that all the materials had good moldability.

Regarding the various test pieces thus obtained, J I
Impact resistance was evaluated using notched Izot impact strength (kg-cm/cm) at room temperature according to JLS-6871, and heat resistance was evaluated according to JLS-6871.
Evaluation was made at the heat distortion temperature (C) according to the following.

In addition, for these various test pieces,
Apply urethane coating (Ohashi Kagaku Co., Ltd.: Ravi coating) to a thickness of approximately 40 μm, bake at 80°C for 30 minutes, leave for 3 days, and apply according to the JIS-5400 test method. A goblin test was performed to determine the adhesion of the paint film (
Adhesion) was evaluated. The paint for urethane coating was solidified by blending 100 parts by weight of Ravi MF enamel as a main ingredient, 25 parts by weight of hardening agent M-60, and 50 parts by weight of thinner 8600. In addition, in the above adhesive evaluation, 300/300 indicates that none of the 100 interlocking coatings provided at three locations was peeled off, and that the coating had excellent coating adhesion. Further, the appearance after the urethane coating was visually evaluated, and the results are also shown in Table 1 below.

As is clear from the results in Table 1, HIPS material is melt-kneaded with a predetermined amount of a vinyl compound (maleic anhydride/itaconic anhydride) and an organic peroxide according to the present invention. While maintaining effective physical properties such as heat resistance, impact resistance, and moldability, excellent results were obtained in the adhesion and appearance of the urethane coating, but HIP S
In the case of the material itself, the adhesion of urethane coating is poor, and even if the amount of maleic anhydride, itaconic anhydride, or organic oxide is too small or too large, the adhesion of urethane coating may be poor. It is recognized that physical properties such as paint appearance, impact resistance, etc. are deteriorated.

(Effects of the Invention) As is clear from the above description, according to the present invention, a specific amount of an unsaturated carboxylic acid or its anhydride and an organic peroxide are melted and mixed with a styrenic impact-resistant resin material. As a result, it has become possible to obtain an impact-resistant resin material for molding at a low cost that has good adhesion to urethane coatings and good appearance quality without reducing physical properties such as heat resistance and impact resistance. The great industrial significance of the present invention lies in the fact that the applications of styrenic impact-resistant resin materials can be significantly expanded.

Applicant: Kojima Press Industry Co., Ltd.

Claims (1)

[Claims] For 100 parts by weight of a styrenic impact-resistant resin material obtained by graft polymerizing a styrenic monomer to a butadiene rubber containing at least 50% by weight of butadiene,
Impact resistance for molding obtained by blending 0.1 to 3.0 parts by weight of an unsaturated carboxylic acid or its anhydride and 0.01 to 0.5 parts by weight of an organic peroxide and melt-kneading the mixture. resin material.