JP2005076015A - Resin composition for melt fabrication - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition for melt fabrication that is superior in weatherability, chemical resistance and the like, and gives a good mat surface having no gloss unevenness without impairing mechanical characteristics. <P>SOLUTION: The resin composition for melt fabrication is constituted by containing an acrylic rubber-modified thermoplastic resin(A) obtained by grafting a monomer mixture containing at least an aromatic vinyl monomer and a vinyl cyanide monomer to an acrylic rubbery polymer of which average particle sizes are 100-200nm, and a vinyl cyanide-based thermoplastic resin(B) obtained by copolymerizing at least an aromatic vinyl monomer and a vinyl cyanide monomer; and in the resin composition, the ratio of acetone-insoluble components is 20-60 mass%, the difference(SA) between the ratio(RA) of units of the vinyl cyanide in acetone-soluble components to the ratio(GA) of a substance other than the acrylic rubbery polymer in the acetone-insoluble components is 15 mass% or higher. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is excellent in weather resistance and chemical resistance without impairing mechanical properties, and in melt processing such as extrusion molding and blow molding, a resin composition and molding for melt processing that give a good matte surface without uneven gloss Related to goods.

In general, thermoplastic resins such as ABS resins have good surface gloss and mechanical properties and are used in various applications, but some automotive interior parts and OA equipment require a non-glossy molding surface. is there.
Examples of conventional matting methods for molded articles are described in Patent Documents 1 to 5, such as (1) a method of applying a texture to a mold surface, and (2) an inorganic filler such as talc or calcium carbonate. (3) a method of adding a rubbery polymer (a rubber particle polymer having a large particle size of 1 to 2 μm), and (4) a method of adding a three-dimensional resin component using a crosslinkable monomer. Can be mentioned.
Japanese Patent Publication No. 49-44582 JP-A-56-133353 JP 59-89346 A JP 60-18536 A Japanese Patent Publication No. 62-59725

However, in the method (1) of applying the embossing to the mold surface, it is difficult to create the embossed surface and maintain the mold, and there are problems such as occurrence of uneven gloss. For (2), there are problems such as roughness of the product surface and impact strength, and for (3), although the matte effect is demonstrated, partial gloss unevenness, variation in impact resistance, mechanical strength There are problems such as a decrease in heat resistance, a decrease in heat resistance, and a decrease in weather resistance, and the practicality is not sufficient. With respect to (4), there is a problem that stable moldability cannot be obtained, and the mechanical strength is remarkably lowered and gloss unevenness occurs on the surface of the molded product.
In particular, molded products by melt processing methods such as extrusion molding and blow molding, unlike injection molded products, have no mold transfer due to pressure, and therefore gloss is affected by the temperature of the polishing roll, mold, resin temperature, etc. It is difficult to control molding conditions and gloss unevenness is likely to occur.

  Furthermore, chemical resistance is required for automobile interior parts and OA equipment, but it has been difficult to satisfy chemical resistance while suppressing uneven gloss.

  The present invention has been made in view of the above circumstances, has excellent weather resistance, chemical resistance, etc. without impairing mechanical properties, and has good gloss without uneven gloss in melt processing such as extrusion molding and blow molding. An object of the present invention is to provide a resin composition for melt processing that gives an erased surface. Furthermore, it aims at providing the molded article which consists of the resin composition for melt processing.

The resin composition for melt processing of the present invention comprises a monomer mixture containing at least an aromatic vinyl monomer and a vinyl cyanide monomer in an acrylic rubbery polymer having an average particle size of 100 to 200 nm. Grafted acrylic rubber-modified thermoplastic resin (A);
A resin composition for melt processing comprising a vinyl cyanide-based thermoplastic resin (B) obtained by copolymerizing at least an aromatic vinyl monomer and a vinyl cyanide monomer,
The acetone insoluble fraction is 20-60% by weight,
The ratio (RA) of vinyl cyanide monomer units in acetone-soluble content, and the ratio (GA) of vinyl cyanide monomer units in polymers other than acrylic rubbery polymers in acetone-insoluble content The difference (SA) is 15% by mass or more.
Moreover, it is preferable that the said resin composition for melt processing contains an inorganic filler.
The molded product of the present invention is obtained by melt-processing a resin composition for melt processing.

According to the resin composition for melt processing of the present invention, it has excellent weather resistance, chemical resistance, etc. without impairing mechanical properties, and good matte without gloss unevenness in melt processing such as extrusion molding and blow molding. Can be obtained.
The molded article of the present invention is particularly suitably used for automobile parts and OA equipment.

<Acrylic rubber-modified thermoplastic resin (A)>
The acrylic rubber-modified thermoplastic resin (A) used in the present invention grafts a monomer mixture containing at least an aromatic vinyl monomer and a vinyl cyanide monomer to an acrylic rubbery polymer. A rubber-containing graft polymer obtained by polymerization. As such an acrylic rubber-modified thermoplastic resin (A), specifically, an AAS resin can be exemplified.

  The acrylic rubber-like polymer constituting the acrylic rubber-modified thermoplastic resin (A) includes, for example, acrylic esters such as ethyl acrylate, butyl acrylate, octyl acrylate, triallyl cyanurate, triallyl isocyanurate. And a polyfunctional monomer such as triacryl formal, diallyl fumarate, ethylene glycol dimethacrylate, and propylene glycol dimethacrylate as a constituent unit. In addition, since a polyfunctional monomer can cross-link acrylic ester, the gel content rate of an acrylic rubber-like polymer can be controlled with the addition amount of a polyfunctional monomer.

The acrylic rubbery polymer needs to have an average particle diameter in the range of 100 to 200 nm, more preferably 100 to 180 nm. When the average particle size is less than 100 nm, the impact resistance is low and practically unsatisfactory, and when it exceeds 200 nm, the matte effect tends to be insufficient.
The particle size distribution is not necessarily unimodal as long as the particle size is within the above range, and may be multimodal, but from the viewpoint of production efficiency, etc., it should be as unimodal as possible. preferable.

  The gel content of the acrylic rubbery polymer is preferably 50 to 95% by mass. When the gel content is less than 50% by mass or more than 95% by mass, the impact strength tends to decrease. Particularly, when the gel content is less than 50% by mass, the optical properties also decrease and the molding shrinkage tends to increase.

There is no restriction | limiting in particular as a manufacturing method of such an acrylic rubber-like polymer, and a particle diameter control method, What kind of polymerization method and control method are employable. For example, a polymerization method using a redox polymerization initiator such as persulfate or cumene hydroperoxide-sodium formaldehyde sulfoxylate by an emulsion polymerization method may be used.
Among the methods for producing an acrylic rubbery polymer, a method using a carboxylic acid emulsifier during emulsion polymerization is preferred. If a carboxylic acid-based emulsifier is used in the emulsion polymerization, the particle diameter can be easily controlled and the weather resistance is further improved.

In addition, sodium pyrophosphate, which is an electrolyte component, can be added during emulsion polymerization. When adding sodium pyrophosphate, the particle size of the acrylic rubbery polymer can be controlled by controlling the amount of sodium pyrophosphate added. That is, when the amount of sodium pyrophosphate added is large, the particle size tends to increase, and when the amount added is small, the particle size tends to decrease.
Further, by increasing the polymerization time, it is possible to increase the particle diameter by taking time to grow the particle diameter. Furthermore, when the particle size of the acrylic rubbery polymer obtained only by polymerization is small (for example, 80 nm), a known particle size such as a chemical aggregation method using an acid or the like or a physical aggregation method using a homomixer or the like is used. The enlargement method can also be adopted.

The monomer mixture to be grafted to the acrylic rubbery polymer contains at least an aromatic vinyl monomer and a vinyl cyanide monomer, and if necessary, a monomer copolymerizable therewith. be able to.
Specific examples of the aromatic vinyl monomer include styrene, α-methylstyrene, o-, m- or p-methylstyrene, vinyl xylene, monochlorostyrene, dichlorostyrene, monobromostyrene, dibromostyrene, fluorostyrene, p -tert-butylstyrene, ethylstyrene, vinylnaphthalene and the like. Among these, styrene and α-methylstyrene are preferable. These can be used alone or in combination of two or more.

  Specific examples of the vinyl cyanide monomer include acrylonitrile and methacrylonitrile, and these can be used alone or in combination of two or more.

  Specific examples of the copolymerizable monomer include α, β-unsaturated carboxylic acids such as acrylic acid and methacrylic acid; methyl (meth) acrylate (“(meth) acrylate” means “acrylate and methacrylate”) Α, β-unsaturated carboxylic acid esters such as ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethyl (meth) acrylate, 2-ethylhexyl methacrylate; maleic anhydride, itaconic anhydride Α, β-unsaturated dicarboxylic acid anhydrides such as acids; imides of α, β-unsaturated dicarboxylic acids such as maleimide, N-methylmaleimide, N-ethylmaleimide, N-phenylmaleimide, and N-o-chlorophenylmaleimide Compounds can be mentioned, and these can be used alone or in combination of two or more. The

  The production method of the acrylic rubber-modified thermoplastic resin (A) is not particularly limited, and a known polymerization method such as a bulk polymerization method, a solution polymerization method, a suspension polymerization method, a bulk suspension polymerization method, or an emulsion polymerization method is employed. it can. For example, a method of emulsion polymerization by adding a monomer mixture and a polymerization initiator in the presence of an acrylic rubbery polymer can be mentioned. There are no particular restrictions on the blending ratio of the acrylic rubbery polymer, aromatic vinyl monomer, vinyl cyanide monomer, and other monomers copolymerizable therewith. Examples of the polymerization initiator used in the emulsion polymerization include redox polymerization initiators such as persulfate or cumene hydroperoxide-sodium formaldehyde sulfoxylate.

  As an example of the production method, an example of an emulsion polymerization method will be described. In this method, first, a rubbery polymer produced by emulsion polymerization is charged into a reactor equipped with a stirring blade and a jacket, and then the whole or a part of the monomer mixture is divided into several times, either collectively or After dripping continuously and leaving to stand at 40 to 70 ° C. with stirring, a polymerization initiator is further added and polymerized to obtain an acrylic rubber-modified thermoplastic resin (A). In such a method, the monomer mixture is impregnated into the acrylic rubbery polymer, and the polymerization easily occurs inside the acrylic rubbery polymer.

  In the acrylic rubber-modified thermoplastic resin (A), the content of the acrylic rubbery polymer is preferably 20 to 90% by mass. When the content of the acrylic rubbery polymer is less than 20% by mass, the graft rate tends to be excessive, and when it exceeds 90% by mass, the graft rate tends to decrease. In either case, the impact strength tends to decrease.

<Vinyl cyanide thermoplastic resin (B)>
The vinyl cyanide-based thermoplastic resin (B) used in the present invention is a copolymer of at least an aromatic vinyl monomer and a vinyl cyanide monomer, and can be copolymerized as necessary. Other monomers can also be copolymerized. The aromatic vinyl monomer, vinyl cyanide monomer, and other copolymerizable monomers used in the production of the vinyl cyanide thermoplastic resin (B) are acrylic rubber-modified thermoplastic resins. The monomer similar to the monomer used for manufacture of (A) can be used.

  The mass% of the vinyl cyanide monomer in the vinyl cyanide-based thermoplastic resin (B) is preferably 30 to 50 mass% in order to improve chemical resistance. When it is less than 30% by mass, the chemical resistance effect is not sufficiently exhibited, and when it exceeds 50% by mass, the thermal stability tends to be deteriorated.

  There is no restriction | limiting in particular as a manufacturing method of a vinyl cyanide-type thermoplastic resin (B), Well-known methods, such as block polymerization method, solution polymerization method, suspension polymerization method, block suspension polymerization method, and emulsion polymerization, are mentioned.

<Resin composition for melt processing>
In the resin composition for melt processing of the present invention, the proportion of insoluble acetone is 20 to 60% by mass, preferably 30 to 60% by mass. If the proportion of acetone insoluble is less than 20% by mass, the matting effect tends to be small and impact resistance tends to be reduced, and if it exceeds 60% by mass, the moldability tends to deteriorate.
Further, in this resin composition for melt processing, the ratio (RA) of vinyl cyanide monomer units in acetone-soluble components and cyanogen in polymers other than acrylic rubbery polymers in acetone-insoluble components. The difference (SA) from the ratio of vinyl fluoride monomer units (GA) is 15% by mass or more, preferably 20% by mass or more, more preferably 20% by mass or more and 40% by mass or less, and particularly preferably. Is 20% by mass or more and 30% by mass or less, and more preferably 20% by mass or more and 25% by mass or less.
If the SA is less than 15% by mass, the matte effect is not sufficiently exhibited. Moreover, when SA exceeds 40 mass%, it may color at the time of shaping | molding, and it is unpreferable.
In the melt processing resin composition, the mixing ratio of the acrylic rubber-modified thermoplastic resin (A) and the vinyl cyanide-based thermoplastic resin (B) is not particularly limited.

  By adding an inorganic filler to the melt processing resin composition of the present invention, it is possible to modify a molded product and improve moldability. Examples of the inorganic filler include glass fiber, glass flake, glass bead, hollow glass, carbon fiber, talc, mica, metal fiber, wollastonite, kaolin, barium sulfate, graphite, molybdenum disulfide, zinc oxide whisker, and oxidation. Examples thereof include magnesium, calcium carbonate, potassium titanate whisker, rock filler and the like, which can be used alone or in combination of two or more. Of these inorganic fillers, glass fibers, glass flakes, carbon fibers, talc, metal fibers, and zinc oxide whiskers are preferable. Moreover, as a shape of glass fiber or carbon fiber, what has a fiber diameter of 5-60 micrometers and a fiber length of 30 micrometers or more is preferable.

  The blending amount of the inorganic filler is usually 1 to 50 parts by mass with respect to 100 parts by mass in total of the acrylic rubber-modified thermoplastic resin (A) and the vinyl cyanide thermoplastic resin (B), preferably It is 1-40 mass parts, More preferably, it is 1-20 mass parts. If the blending amount of the inorganic filler is less than 1 part by mass, the additive effect of the inorganic filler is reduced and the linear expansion coefficient tends to increase, and if it exceeds 50 parts by mass, the molded product surface appearance, chemical resistance, The impact property tends to be low.

  Moreover, the resin composition for melt processing of the present invention does not impair the physical properties and the like of pigments, dyes, lubricants, ultraviolet absorbers, antioxidants, antistatic agents, reinforcing agents, and flame retardants as necessary. It can mix | blend within the range.

  Although there is no restriction | limiting in particular as a method of manufacturing the resin composition for melt processing of this invention, The melt-kneading method is preferable. In the melt-kneading method, for example, an extruder or a Banbury mixer can be used.

The molded product of the present invention is obtained by melt-processing the above-described resin composition for melt processing. As a melt processing method of the resin composition for melt processing, molding methods for processing various molten resins such as profile extrusion molding, blow molding, sheet molding, vacuum molding after forming the sheet, and pressure forming can be employed.
This molded article is suitably used particularly for automobile parts, OA equipment, and housing-related parts. Here, examples of the automobile parts include an instrument panel skin by calender molding, a back garnish by sheet molding (hereinafter, vacuum molding), a spoiler by blow molding, and a side molding by profile extrusion molding. Examples of OA equipment include a printer housing by blow molding, and examples of housing-related parts include sash parts, carport parts, and resin-made bamboo fences by profile extrusion molding.

  The present invention will be described more specifically with reference to the following examples. However, the scope of the present invention is not limited to these examples. In the following, “parts” represents parts by mass.

(Synthesis Example 1) Production of acrylic rubber-modified thermoplastic resin (A) In a pressure-resistant container, 1.5 parts of semi-cured beef tallow soda soap, 0.3 parts of sodium pyrophosphate, and 200 parts of deionized water were charged. The temperature was raised to 80 ° C. under a nitrogen stream, and 100 parts of butyl acrylate, 0.3 part of potassium persulfate and 0.3 part of triallyl cyanurate were added dropwise over 4 hours for polymerization. After completion of the dropwise addition, the reaction was terminated after cooling for 1 hour and then cooling.
To 100 parts of the resulting polybutyl acrylate latex (in terms of solid content), 0.15 part of sodium dodecylbenzenesulfonate was added, and 5% aqueous acetic acid solution and 10% sodium hydroxide were added dropwise to enlarge the particles. . A monomer mixture composed of 28 parts of styrene and 12 parts of acrylonitrile is blended with 60 parts of the polybutyl acrylate latex of the enlarged particles (in terms of solid content), and emulsion polymerization is carried out at 60 to 70 ° C. for 3 hours. It was coagulated, washed with water, dehydrated and dried to synthesize an acrylic rubber-modified thermoplastic resin (A1).
The average particle size of the acrylic rubber-modified thermoplastic resin (A1) was measured by a dynamic light scattering method using Microtrac Model: 9230UPA manufactured by Nikkiso Co., Ltd. The results are shown in Table 1.

(Synthesis Examples 2 to 4)
Acrylic rubber-modified thermoplastic resins (A2 to A4) were synthesized in the same manner as in Synthesis Example 1 except that the composition of the monomer mixture was changed as shown in Table 1. The results of measuring these average particle sizes are shown in Table 1.

(Synthesis Example 5) Production of vinyl cyanide-based thermoplastic resin (B) In a reactor purged with nitrogen, 120 parts of water, 0.02 part of sodium alkylbenzenesulfonate, 0.5 part of polyvinyl alcohol, 0.3 parts of azoisobutylnitrile And a monomer mixture consisting of 49 parts of acrylonitrile and 51 parts of styrene, heated at a starting temperature of 60 ° C. for 5 hours, then heated to 120 ° C. and reacted for 4 hours to give a vinyl cyanide-based thermoplastic resin (B1) Was synthesized.

(Synthesis Examples 6-8)
Vinyl cyanide-based thermoplastic resins (B2 to B4) were synthesized in the same manner as in Synthesis Example 5 except that the composition of the monomer mixture was changed as shown in Table 2.

(Examples 1-5, Comparative Examples 1-6)
In 100 parts of a mixture of the acrylic rubber-modified thermoplastic resins (A1 to A4) obtained in Synthesis Examples 1 to 4 and the vinyl cyanide thermoplastic resins (B1 to B4) obtained in Synthesis Examples 5 to 8 Then, 0.5 parts of a lubricant and 10 parts of calcium carbonate as an inorganic filler were mixed, and melt-kneaded with a Banbury mixer to be pelletized. Using the pellets obtained in each example and comparative example, the following evaluation test was performed. The results are shown in Tables 3 and 4.

(Acetone insoluble and soluble content analysis)
The obtained resin composition for melt processing is mixed with chloroform, reprecipitated with methanol and filtered to remove additives and calcium carbonate, and the obtained insoluble matter is dissolved in acetone and left for 24 hours. It became a solution. Next, this solution was centrifuged at 30000 rpm with a centrifuge to separate the acetone soluble component and the acetone insoluble component, and then methanol was added to the acetone solution in which the acetone soluble component was dissolved, followed by reprecipitation and filtration. As a result, an acetone-soluble component was obtained as a solid component. Acetone-insoluble matter and acetone-soluble matter were dried with a vacuum dryer and weighed each to determine the acetone-soluble matter mass and acetone-insoluble matter mass. Thereafter, the acetone-soluble matter was added to C.I. H. N. The nitrogen content (N value) was determined by elemental analysis using an O coder (manufactured by Yanaco: CHN CORDER MT-3). Next, the amount of vinyl cyanide monomer was calculated by converting the N value, and the ratio (RA) of vinyl cyanide monomer units in the acetone-soluble matter was determined.
On the other hand, the acetone-insoluble content was determined by pyrolysis gas chromatography (manufactured by Shimadzu Corporation: decomposition temperature 590 ° C.) to determine the proportion of each monomer unit in the acetone-insoluble content, and the acrylic rubber polymer mass was determined. In addition, acetone insoluble matter was removed from C.I. H. N. Elemental analysis was performed using an O coder to determine the nitrogen content (N value). Next, the N value was converted to calculate the amount of vinyl cyanide monomer, and the proportion of vinyl cyanide monomer units was determined.
Each value obtained was substituted into the following formula to determine the proportion (GA) of vinyl cyanide monomer units in the polymer other than the acrylic rubbery polymer in the acetone insoluble matter.
GA = mass of vinyl cyanide monomer unit in acetone insoluble matter / (mass of acetone insoluble matter mass-acrylic rubbery polymer unit mass in acetone insoluble matter)

(Surface gloss)
A plate-like extruded product is produced with a 20 mm extruder, and the surface of the molded product is subjected to an incident angle of 60 ° and a reflection angle of 60 ° using a digital goniophotometer UGV-5D manufactured by Suga Test Instruments Co., Ltd. The reflectance was measured.

(Formability)
When producing a plate-shaped profile extrusion molded product with a 20 mm extruder, it was judged by visual observation, ◎ was very good, ○ was good, and × was bad.

(Wear resistance)
The extruded product was cut out, and a sunshine weatherometer (“Sunshine Super Long Life Weatherometer WEL-6XS-HCH-B”, manufactured by Suga Test Instruments Co., Ltd.) was used as a light acceleration tester. A weather resistance test was conducted for 2000 hours at 3 ° C. with spraying, and the change in color tone (ΔE) after irradiation was measured.

(chemical resistance)
After fixing the strip-shaped test piece shape 150x10x2mm produced by injection molding along the bending home method test jig, apply the chemical solution to the test piece and leave it at 23 ° C for 48 hours, then craze The occurrence of cracks was confirmed and the critical strain (%) was determined from the curvature of the test jig. Este Chemical Co., Ltd. Powers was used as the chemical solution.

(Charpy impact strength)
Using a 2 ounce injection molding machine (manufactured by Toshiba Machine Co., Ltd.), necessary test pieces were prepared and measured according to ISO 179.

(Tensile strength)
Using a 2 ounce injection molding machine (manufactured by Toshiba Machine Co., Ltd.), necessary test pieces were prepared and measured according to ISO 527.

(Flexural modulus)
Using a 2 ounce injection molding machine (manufactured by Toshiba Machine Co., Ltd.), necessary test pieces were prepared and measured according to ISO 178.

As is clear from Table 3, the melt processing resin compositions of Examples 1 to 5 are excellent in moldability, weather resistance, and chemical resistance without deteriorating mechanical properties, and have a sufficient matting effect. Could get to.
On the other hand, in Comparative Examples 1 and 6, since the difference (SA) in vinyl cyanide monomer units was less than 15%, a sufficient matting effect could not be obtained and the chemical resistance was also low.
In Comparative Example 2, since the average particle size of the acrylic rubbery polymer in the acrylic rubber-modified thermoplastic resin (A) exceeded 200 nm, a sufficient matting effect could not be obtained.
In Comparative Example 3, since the average particle size of the acrylic rubbery polymer in the acrylic rubber-modified thermoplastic resin (A) was less than 100 nm, the impact resistance was low.
In Comparative Example 4, since the acetone insoluble content was less than 20% by mass, the matte effect was small and the impact resistance was low.
In Comparative Example 5, the amount of acetone insolubles exceeded 60% by mass, so the moldability was low.

  The resin composition for melt processing and the molded product of the present invention are particularly used for automobile interior parts and OA equipment.

Claims (3)

An acrylic rubber-modified thermoplastic resin (A) in which a monomer mixture containing at least an aromatic vinyl monomer and a vinyl cyanide monomer is grafted to an acrylic rubber polymer having an average particle size of 100 to 200 nm. )When,
A resin composition for melt processing comprising a vinyl cyanide-based thermoplastic resin (B) obtained by copolymerizing at least an aromatic vinyl monomer and a vinyl cyanide monomer,
The acetone insoluble fraction is 20-60% by weight,
The ratio (RA) of vinyl cyanide monomer units in acetone-soluble content, and the ratio (GA) of vinyl cyanide monomer units in polymers other than acrylic rubbery polymers in acetone-insoluble content The resin composition for melt processing is characterized by having a difference (SA) of 15% by mass or more.   The resin composition for melt processing according to claim 1, comprising an inorganic filler.   A molded product obtained by melt-processing the resin composition for melt processing according to claim 1.