JP2001106851A - Molding material and preparation of molded article and molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a molding material capable of obtaining molded articles having excellent chemical resistance and mechanical strength even when the melt kneading step is omitted and the molding is conducted at the conventional molding temperature of an atactic polystyrene in molding a styrenic polymer, a process for producing molded articles by using the molding material which shortens the molding cycle to reduce the production cost, and its molded articles. SOLUTION: The molding material is composed of a dry blend of (A) 10-95 wt.% styrenic polymer having an atactic structure and (B) 5-90 wt.% styrenic polymer mainly having a syndiotactic structure which has a melting point of not higher than 245 deg.C and a weight average molecular weight of not greater than 200,000. A process for producing molded articles comprises molding this molding material at a resin temperature of not higher than 260 deg.C and a molded product is obtained by this process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding material comprising a dry blend of a styrene resin, a method for producing a molded article using the same, and a molded article thereof. More specifically, a molding material comprising a dry blend of a styrene-based polymer having an atactic structure and a styrene-based polymer having a predominantly syndiotactic structure having specific physical properties, and a method for producing a molded article using the same And its molded products.

[0002]

2. Description of the Related Art Conventionally, a styrenic polymer having an atactic structure produced by a radical polymerization method (hereinafter, referred to as a styrene polymer).
Atactic polystyrene) is used in various applications because it can be obtained at low cost. By the way, this atactic polystyrene is amorphous because its tertiary structure is an atactic structure, and the solvent resistance is not always satisfactory. Therefore, the field which can be applied as a molding material has been limited.
Furthermore, a resin composition in which polyphenylene ether is blended with this atactic polystyrene is also known, but this resin was similarly unsatisfactory in solvent resistance.

In order to improve the solvent resistance, a method of copolymerizing styrene with a polar monomer such as acrylonitrile, methacrylate, acrylate, maleic anhydride, and maleimide has been adopted. However, the copolymer obtained in this case is that the random copolymerization ratio is limited, that the productivity is low, that the color tone is not good, that there is an odor, and that it is different from other polystyrene resins. There is a problem that it is difficult to mix and recycle.

Therefore, as an alternative to amorphous atactic polystyrene having such difficulties, syndiotactic polystyrene having crystallinity has been developed.
Further, a resin composition in which the syndiotactic polystyrene is blended with another resin to improve its heat resistance has also been proposed (JP-A-62-104818, JP-A-62-257948, JP-A-62-257948). -257950
JP, JP-A-1-182344, etc.).

However, in the case of producing a styrene resin composition by blending this syndiotactic polystyrene with atactic polystyrene, in order to sufficiently exhibit physical properties such as solvent resistance and mechanical strength, the composition must be improved. Prior to molding the product into a molded article, it is necessary to perform melt-kneading, and also about the molding processing temperature of this composition, it is necessary to perform at a temperature higher than the normal atactic polystyrene molding processing temperature, In addition, there is a problem that the molding cycle is reduced and a thick portion of the molded product is shrunk.

[0006]

The object of the present invention is to eliminate the need for a melt-kneading step when molding a styrenic polymer and to obtain a solvent-resistant or mechanical strength even when molded at the usual processing temperature for atactic polystyrene. The object of the present invention is to provide a molding material capable of obtaining a molded product excellent in quality, a method for producing a molded product in which a molding cycle using the molding material is shortened and production costs are reduced, and a molded product thereof It is.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted various studies to solve the above-mentioned problems in the prior art, and as a result, if syndiotactic polystyrene having specific physical properties is blended with atactic polystyrene, Omission of the melt-kneading step, and, even if the molding temperature is the same temperature as ordinary atactic polystyrene, found that a molded product with good physical properties such as solvent resistance and mechanical strength can be obtained. The present invention has been completed based on the findings.

That is, the gist of the present invention is as follows. [1] (A) 10 to 95% by weight of a styrenic polymer having an atactic structure, and (B) mainly having a syndiotactic structure having a melting point of 245 ° C. or less and a weight average molecular weight of 200,000 or less. A molding material comprising a dry blend of 5 to 90% by weight of a styrene polymer. [2] The molding material according to [1], wherein the initial relative crystallinity of the styrene-based polymer having a syndiotactic structure as the component (B), measured by a differential scanning calorimeter, is 60% or less. [3] A method for producing a molded article, wherein the molding material according to [1] or [2] is molded at a resin temperature of 260 ° C. or lower. [4] A molded article produced by the method for producing a molded article according to [3].

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to (A) 10 to 95% by weight of a styrenic polymer having an atactic structure,
(B) A molding material comprising a dry blend of 5-90% by weight of a styrene polymer having a syndiotactic structure and having a melting point of 245 ° C. or less and a weight average molecular weight of 200,000 or less.

The styrenic polymer having an atactic structure of the component (A) used in the present invention is obtained by a generally used method such as solution polymerization, bulk polymerization, suspension polymerization, or bulk-suspension polymerization. Things are used. And as a raw material monomer used in the production of this atactic polystyrene, the following general formula (1):

[0011]

Embedded image

[In the formula (1), R is each independently a hydrogen atom,
A halogen atom or a substituent containing at least one atom selected from the group consisting of a carbon atom, an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, a selenium atom, a silicon atom and a tin atom; Indicates an integer. However, when m is plural, each R may be the same or different. ] Is used. Further, a copolymer with one or more of the aromatic vinyl compounds represented by the general formula (1) and another vinyl monomer or a rubbery polymer which can be copolymerized, It may be a hydride of a combination or a copolymer or a mixture thereof.

The aromatic vinyl compound represented by the general formula (1) includes, for example, styrene, α-methylstyrene, methylstyrene, ethylstyrene, isopropylstyrene, tertiary butylstyrene, phenylstyrene, vinylstyrene, and chlorobenzene. Examples include styrene, bromostyrene, fluorostyrene, chloromethylstyrene, methoxystyrene, and ethoxystyrene. Among them, particularly preferred aromatic vinyl compounds include
Styrene, p-methylstyrene, m-methylstyrene,
p-tert-butylstyrene, p-chlorostyrene, m-chlorostyrene and p-fluorostyrene. These may be used alone or as a mixture of two or more.

Other vinyl monomers copolymerizable with the aromatic vinyl compound include, for example, vinyl cyanide compounds such as acrylonitrile and methacrylonitrile;
Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, 2
Acrylates such as ethylhexyl acrylate, cyclohexyl acrylate, dodecyl acrylate, octadecyl acrylate, phenyl acrylate, benzyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, Dodecyl methacrylate, octadecyl methacrylate, phenyl methacrylate,
Methacrylic acid esters such as benzyl methacrylate,
Maleimide compounds such as maleimide, N-methylmaleimide, N-ethylmaleimide, N-butylmaleimide, N-laurylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N- (p-bromophenyl) maleimide and the like. .

The rubbery polymer copolymerizable with the aromatic vinyl compound includes, for example, polybutadiene,
Diene rubbers such as styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, polyisoprene, ethylene-α-olefin copolymer, ethylene-α
-Non-diene rubbers such as olefin-polyene copolymers, polyacrylates, styrene-butadiene block copolymers, hydrogenated styrene-butadiene block copolymers, ethylene-propylene elastomers, styrene-graft-ethylene-propylene elastomers , An ethylene ionomer resin, a hydrogenated styrene-isoprene copolymer, and the like.

The molecular weight of the atactic polystyrene used as the component (A) is not particularly limited, but generally has a weight average molecular weight of 10,000 or more, preferably 50,000 or more. Here, if the weight average molecular weight is less than 10,000, the thermal properties and mechanical properties of the obtained molded article are undesirably reduced. Furthermore, there is no restriction on the molecular weight distribution, and various molecular weight distributions can be applied.

Further, in order to improve the impact resistance of the molded article produced in the present invention, a rubber-like elastic body can be used in combination as a part of the component (A) according to the purpose.
Specific examples of the rubber-like elastic body that can be used here include, for example, natural rubber, polybutadiene, polyisoprene, polyisobutylene, neoprene, polysulfide rubber, thiochol rubber, acrylic rubber, urethane rubber, silicone rubber, epichlorohydrin rubber, Styrene-butadiene block copolymer (SBR), hydrogenated styrene-butadiene block copolymer (SEB, SEB
C), styrene-butadiene-styrene block copolymer (SBS), hydrogenated styrene-butadiene-styrene block copolymer (SEBS), styrene-isoprene block copolymer (SIR), hydrogenated styrene-isoprene block copolymer Copolymer (SEP), styrene-isoprene-styrene block copolymer (SIS), hydrogenated styrene-isoprene-styrene block copolymer (SEPS), or ethylene propylene rubber (EP
M), ethylene propylene diene rubber (EPDM), or butadiene-acrylonitrile-styrene-core-shell rubber (ABS), methyl methacrylate-butadiene-styrene-core-shell rubber (MBS), methyl methacrylate-butyl acrylate-styrene-core-shell rubber (MAS) Octyl acrylate-butadiene-styrene-core-shell rubber (MABS), alkyl acrylate-butadiene-acrylonitrile-styrene-core-shell rubber (ABS), butadiene-styrene-core-shell rubber (SBR), methyl methacrylate-butyl acrylate-siloxane. Core-shell type particle-like elastic bodies such as siloxane-containing core-shell rubbers, or rubbers obtained by modifying the same are exemplified. Of these, SBR, SEB, SBS, SEB
S, SIR, SEP, SIS, SEPS, core shell rubber, EPM, EPDM, or a rubber modified from these is particularly preferably used. One of these rubber-like elastic bodies may be used alone, or two or more thereof may be used.

The rubber-like elastic material used as a part of the above component (A) is compounded in an amount of not more than 80% by weight, preferably not more than 60% by weight, more preferably not more than 50% by weight of the whole component (A). It is good to do. This is 8
If the content exceeds 0% by weight, the solvent resistance and the elastic modulus may be reduced.

Further, in order to improve the heat resistance of the molding material of the present invention, polyphenylene ether can be blended as a part of the component (A). Polyphenylene ethers suitable for use herein include, for example, U.S. Pat. Nos. 3,306,874, 3,306,875, and 32.
What is described in each specification of 57357 and 3257358 is preferable. This polyphenylene ether is prepared by an oxidative coupling reaction of a phenol having one or more substituents in the presence of a copper amine complex or the like to form a homopolymer or a copolymer. You. As the copper amine complex, a copper amine complex derived from a primary amine, a secondary amine or a tertiary amine is preferably used.

Examples of the polyphenylene ether suitable for use as a part of the component (A) include poly (2,3-dimethyl-6-ethyl-1,4-phenylene ether) and poly (2-methyl -6-chloromethyl-
1,4-phenylene ether), poly (2-methyl-6)
-Hydroxyethyl-1,4-phenylene ether),
Poly (2-methyl-6-n-butyl-1,4-phenylene ether), poly (2-ethyl-6-isopropyl-)
1,4-phenylene ether), poly (2-ethyl-6)
-N-propyl-1,4-phenylene ether), poly (2,3,6-trimethyl-1,4-phenylene ether), poly (2- (4'-methylphenyl) -1,4-
Phenylene ether), poly (2-bromo-6-phenyl-1,4-phenylene ether), poly (2-methyl-6-phenyl-1,4-phenylene ether), poly (2-phenyl-1) , 4-phenylene ether), poly (2-chloro-1,4-phenylene ether), poly (2-methyl-1,4-phenylene ether), poly (2-chloro-6-ethyl-1, 4-phenylene ether), poly (2-chloro-6-bromo-1,4-phenylene ether), poly (2,6-di-n-propyl-)
1,4-phenylene ether), poly (2-methyl-6)
-Isopropyl-1,4-phenylene ether), poly (2-chloro-6-methyl-1,4-phenylene ether), poly (2-methyl-6-ethyl-1,4-phenylene ether), Poly (2,6-dibromo-1,4-phenylene ether), poly (2,6-dichloro-1,4
-Phenylene ether), poly (2,6-diethyl-)
1,4-phenylene ether) and poly (2,6-dimethyl-1,4-phenylene ether).
Among these, poly (2,6-dimethyl-1,4-phenylene ether) is particularly preferred.

In addition to homopolymers of these phenol compounds, copolymers of two or more of these may be used. Further, these polymers and copolymers may be modified with a modifying agent such as maleic anhydride or fumaric acid. Further, a graft copolymer or a block copolymer of a vinyl aromatic compound such as styrene and the above-mentioned polyphenylene ether may be used.

The polyphenylene ether used herein has an intrinsic viscosity of 0.5 deciliter / g or less, preferably 0.5 mL, measured at 25 ° C. in chloroform.
It is preferably 45 deciliters / g or less. If the intrinsic viscosity exceeds 0.5 deciliters / g, the resulting molding material may have a low fluidity during molding.

Further, regarding the mixing ratio when the polyphenylene ether is compounded as the component (A),
This is added in an amount of 5 to 80% by weight, preferably 1 to 80% by weight of the whole component (A).
The amount is 0 to 60% by weight. If the compounding ratio of the polyphenylene ether is less than 5% by weight, the effect of improving the heat resistance is not sufficient, and if the compounding ratio of the polyphenylene ether exceeds 80% by weight, the flowability of the resulting molding material during molding is reduced. This may cause a decrease in the value.

Next, in the above-mentioned styrenic polymer having a predominantly syndiotactic polystyrene structure, a syndiotactic structure means that the stereochemical structure is a syndiotactic structure, that is, the main chain formed from carbon-carbon bonds. On the other hand, a phenyl group as a side chain has a steric structure in which the phenyl groups are alternately located in opposite directions. In this case, the tacticity is determined by nuclear magnetic resonance using isotope carbon [ ¹³
C-NMR].

The tacticity measured by the ¹³ C-NMR method is the proportion of a plurality of continuous structural units, for example, a dyad for two, a triad for three, and a triad for five. Although it can be shown by a pentad, in the present invention, the styrene-based polymer mainly having a syndiotactic structure is usually 75% or more, preferably 85% or more in a racemic diad, or 30% or more in a racemic pentad. , Preferably 50
% Of styrene-based polymer or copolymer having a syndiotacticity of not less than%.

Examples of such a styrene polymer or copolymer include polystyrene, poly (alkylstyrene), poly (halogenated styrene), poly (halogenated alkylstyrene), poly (alkoxystyrene) and poly (alkoxystyrene). Vinyl benzoate), hydrogenated polymers thereof and mixtures thereof, or copolymers containing these as main components are used.

Specific examples of the poly (alkyl styrene) include, for example, poly (methyl styrene), poly (ethyl styrene), poly (isopropyl styrene), poly (tertiary butyl styrene), poly (phenyl styrene) ), Poly (vinylnaphthalene), poly (vinylstyrene) and the like. Examples of the poly (halogenated styrene) include poly (chlorostyrene), poly (bromostyrene), and poly (fluorostyrene). Further, as poly (halogenated alkylstyrene),
Examples include poly (chloromethylstyrene), and examples of poly (alkoxystyrene) include poly (methoxystyrene) and poly (ethoxystyrene). Among these, particularly preferred styrene polymers include polystyrene, poly (p-methylstyrene), poly (m-methylstyrene), poly (p-tert-butylstyrene), poly (p-chlorostyrene), and poly (p-chlorostyrene). (M
-Chlorostyrene), poly (p-fluorostyrene),
Examples include hydrogenated polystyrene and copolymers containing these structural units.

The method for producing such a styrenic polymer having a predominantly syndiotactic structure is described in a known method, for example, in an inert hydrocarbon solvent or a solvent described in JP-A-62-187708. A method of polymerizing a styrene monomer in the absence of a styrene monomer and a condensation product of water and a trialkylaluminum as a catalyst. Poly (halogenated alkylstyrene) and hydrogenated polymers thereof are also known in the art, for example, as described in JP-A-1-4691.
No. 2, JP-A-1-178505, and the like.

The styrenic polymer mainly having a syndiotactic polystyrene structure used as the component (B) of the molding material in the present invention is obtained as described above. And those having a weight average molecular weight of 200,000 or less are used. The weight average molecular weight is a value measured at 135 ° C. by gel permeation using trichlorobenzene as a solvent.

Here, as the polymer of the component (B),
If the melting point exceeds 245 ° C., the mixture obtained by dry blending with the atactic polystyrene of the component (A) is to be molded at the usual molding temperature of atactic polystyrene. Is not sufficient, and the resulting molded article will have reduced solvent resistance and mechanical strength.

When a polymer having a weight average molecular weight of more than 200,000 is used as the polymer of the component (B), the mixture obtained by dry blending with the atactic polystyrene of the component (A) can be used. At the normal atactic polystyrene molding temperature, the mixing in the cylinder of the molding machine is not enough,
The resulting molded article will have reduced solvent resistance and mechanical strength.

Further, a polymer having an initial relative crystallinity of 60% or less, preferably 50% or less, more preferably 40% or less as measured by a differential scanning calorimeter of the component (B) is suitably used. Can be When a polymer having an initial relative crystallinity of 60% or less is used, it is obtained by dry blending with the atactic polystyrene of the component (A), compared with a polymer having this value exceeding 60%. When molding a molding material at the usual molding temperature of atactic polystyrene, the melting properties of the molding material in the molding machine cylinder are improved, and the resulting molded product also has an improved solvent resistance and mechanical strength. Excellent things will be obtained.

Next, regarding the mixing ratio of the atactic polystyrene of the component (A) and the styrene-based polymer having a syndiotactic polystyrene structure of the component (B), the content of the component (A) is 10 to 95% by weight. When,
(B) The proportion of the component is 5 to 90% by weight. The more preferable mixing ratio of the component (A) is 20 to 90% by weight, and the more preferable mixing ratio is 50 to 85% by weight. The more preferable mixing ratio of the component (B) is 10 to 80% by weight, and the more preferable mixing ratio is 15 to 50% by weight. Here, if the compounding ratio of the component (A) exceeds 95% by weight or the compounding ratio of the component (B) is less than 5% by weight, the components (A) and (B) are dry-blended and then molded. The effect of improving the solvent resistance and mechanical strength of the molded article obtained by the above method is not sufficiently exhibited. Further, whether the blending ratio of the component (A) is less than 10% by weight,
If the blending ratio of the component (B) exceeds 90% by weight, it is disadvantageous in terms of cost.

The molding material of the present invention contains 10 to 95% by weight of the component (A) and 5 to 90% by weight of the component (B). Nucleating agents, plasticizers, mold release agents, additives such as antioxidants, flame retardants, flame retardant aids, dyes, pigments, antistatic agents, etc., or thermoplastic resins, rubbers And the like. These additives and thermoplastic resins,
When rubber or the like is blended, it may be blended in advance with the component (A) or the component (B), or may be dry-blended simultaneously with the component (A) and the component (B) when dry-blending.

The nucleating agent is added to promote the crystallization of the styrene polymer having the syndiotactic polystyrene structure of the component (B) and to further increase the solvent resistance. Examples of the nucleating agent include metal salts of carboxylic acids such as aluminum di (pt-butylbenzoate) and metal salts of phosphoric acid such as sodium methylenebis (2,4-di-t-butylphenol) acid phosphate. , Talc, phthalocyanine derivatives and the like are used. These may be used alone or in combination of two or more.

Examples of the plasticizer include polyethylene glycol, polyamide oligomer, ethylene bisstearamide, phthalate, polystyrene oligomer, polyethylene wax, mineral oil and silicone oil. They may be used alone or in combination of two or more.

As the release agent, for example, polyethylene wax, silicone oil, long-chain carboxylic acid, metal salt of long-chain carboxylic acid, etc. may be used alone.
Two or more kinds may be used in combination.

As the antioxidant, there are various compounds. Among them, known compounds such as phosphorus compounds, phenol compounds and sulfur compounds can be arbitrarily selected and used.

Further, as the above flame retardant, brominated polystyrene, brominated syndiotactic polystyrene,
Brominated polymers such as brominated polyphenylene ether,
It can be arbitrarily selected from brominated aromatic compounds such as brominated diphenylalkane and brominated diphenyl ether, and phosphorus-based flame retardants such as tricresyl phosphate, triphenyl phosphate and tris-3-chloropropyl phosphate. As the flame retardant aid, an antimony compound such as antimony trioxide can be used. Teflon or the like can be used as the anti-drip agent. These flame retardants and the like may be used alone or in combination of two or more.

The thermoplastic resin includes linear high-density polyethylene, linear low-density polyethylene, high-pressure low-density polyethylene, isotactic polypropylene, syndiotactic polypropylene, block polypropylene, random polypropylene, polybutene, and the like.
1,2-polybutadiene, cyclic polyolefin, poly-
Polyolefin resin such as 4-methylpentene, polystyrene, impact-resistant polystyrene, polystyrene resin such as ABS resin, AS resin, SMA resin, polyester resin such as polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyamide 6, polyamide 6 , And 6 may be used alone or in combination of two or more.

Next, in order to produce the molding material of the present invention, the components (A) and (B) and, if necessary, the above-mentioned various additives are appropriately blended and dry-blended. Good. There is no particular limitation on the equipment used for the dry blending, and a Henschel mixer, a ribbon mixer, a tumble mixer, or the like can be used.

The molding material thus obtained by dry blending can be directly supplied to a molding machine without melting and kneading to produce a molded article. Therefore, one step in molding can be omitted, which is economical, and at the same time, the degree of deterioration of the resin component due to the heat history is reduced.

The method for producing a molded article using the molding material of the present invention is not particularly limited, and it can be produced by a known method such as injection molding or extrusion molding. And the resin temperature at the time of molding in this case may be equal to the molding temperature of ordinary atactic polystyrene,
260 ° C. or lower, preferably 250 ° C. or lower. When the molding temperature exceeds 260 ° C., the molding cycle is lengthened, the productivity is reduced, and the thick part of the obtained molded product is greatly shrunk.

As described above, in a molding material comprising the atactic polystyrene and the syndiotactic polystyrene of the present invention and having improved solvent resistance and mechanical properties, the molding temperature is set to a temperature as low as that of atactic polystyrene. The melting point of the component (B) in the molding material of the present invention is 245 ° C. or less,
The use of polystyrene having a syndiotactic structure with a weight-average molecular weight of 200,000 or less is caused. On the other hand, in a conventionally known styrene resin composition composed of atactic polystyrene and syndiotactic polystyrene, the melting point of the syndiotactic polystyrene component exceeds 245 ° C. and the weight average molecular weight is 200,000. Since the temperature of the resin is higher than 260 ° C during molding, the energy consumption required for heating and cooling is large, and the molding cycle is long, resulting in low productivity and the resulting molded product However, there was a drawback that the shrinkage in the thick part became large.

The molded article of the present invention thus formed is excellent in solvent resistance and chemical resistance, and is also improved in mechanical properties such as impact strength and elongation, so that it can be used for various applications in a wide range of industrial fields. Can be used. For example, in the case of injection-molded products, automotive exterior parts such as radiator grills, grills, marks, back panels, door mirrors, wheel caps, air spoilers, motorcycle cowls; instrument panels, meter hoods, pillars, glove boxes, Automotive interior parts such as console boxes, speaker boxes and lids; AV equipment such as housings, chassis, cassette cases, CD magazines and remote control cases; parts such as lining, trays, arms, door caps and handles for electric refrigerators; Parts of housings, handles, pipes, inlets, etc. of air conditioners; housings of fans, fans, remote control cases; electric equipment and parts such as electric fans, ventilation fans, washing machines, lighting equipment parts, battery cases; housings of printers and copiers And chassis Parts such as ribbon cassettes and trays; PC housings and floppy disk shells, keyboards; telephones and communication equipment housings and receivers, mechanical chassis; general equipment and parts such as sewing machines, registers, typewriters, calculators, optical instruments, musical instruments, etc. Remote control cars and blocks, pachinko machine parts, surfboards, helmets and other toys, leisure and sporting goods; toilet seats, toilet bowls, tanks, showers and other sanitary goods; lunch boxes, various containers, pots and other kitchenware; stationery; furniture Building material housing parts; industrial structural materials such as pipes, containers and trays;

The extruded product is suitably used as a basic industrial material such as films, sheets, pipes, and filaments.

[0047]

[Examples 1 to 22]

[1] Selection of Component (A) The following four types of styrene resins (a-1) to (a-4) and styrene resin compositions are used as the atactic polystyrene as the component (A) of the molding material of the present invention. Was selected. (A-1): Impact-resistant polystyrene resin [made by Idemitsu Petrochemical: IT-44] (a-2): Impact-resistant polystyrene resin [made by Idemitsu Petrochemical: HT-52] (a-3): 80% by weight of impact-resistant polystyrene [IT-44 manufactured by Idemitsu Petrochemical Co., Ltd.] and polyphenylene oxide resin [manufactured by Mitsubishi Engineering Plastics:
YPX-100L] 20% by weight. (A-4): 50% by weight of high-impact polystyrene [IT-44 manufactured by Idemitsu Petrochemical Co., Ltd.] and polyphenylene oxide resin [manufactured by Mitsubishi Engineering Plastics:
YPX-100L] 50% by weight. [2] Selection of Component (B) The styrenic polymer mainly having a syndiotactic structure, which is the component (B) of the molding material of the present invention, was produced by the method described in JP-A-62-104818. Six types of styrene-based resins (b-1) to (b-6) shown in Table 1 below were selected.

[0048]

[Table 1]

In Table 1, the mol% in parentheses in the resin composition column indicates the content of p-methylstyrene. The weight-average molecular weight and the molecular weight distribution [weight-average molecular weight / number-average molecular weight] shown in the table were determined by gel permeation chromatography using 1,2,4-trichlorobenzene as a solvent at 135 ° C. This is a value measured and converted to polystyrene. The melting point was measured using a differential scanning calorimeter, and determined by the melting peak position at a heating rate of 20 ° C./min. Furthermore, the initial relative crystallinity was measured using a differential scanning calorimeter, and the absolute value of the cold crystallization peak area per unit weight at a heating rate of 20 ° C./min ΔH _TCC (J
/ G) and the absolute value of the melting peak area per unit weight 重量
It is a value calculated from H _Tm (J / g) by the following equation.

[0050]

(Equation 1)

[3] Dry Blend of Component (A) and Component (B) and Production of Molded Article The above component (A) and component (B) were mixed with a Henschel mixer at a mixing ratio shown in Table 2 below. Dry blending, and then injection molding with the mold temperature set at 40 ° C to produce Izod test pieces, tensile test pieces, bending test pieces, and 1.6 mm thick rod-shaped test pieces for solvent resistance evaluation. did. [4] Evaluation of moldability and mechanical strength As the evaluation of moldability at the time of injection molding in the above [3], regarding the molding cycle, (A) in each combination of the component (A) and the component (B) was used. Compared to the molding cycle when molding only the components, it is possible to mold even if the cooling time is equal; ○ It is necessary to extend the cooling time by 1 to 5 seconds; △ Extend the cooling time by 5 seconds or more Necessary items are shown in Table 2 as x.

As for the evaluation of the moldability during the injection molding in the above [3], the shrinkage was evaluated in the case where the component (A) in the combination of the respective components (A) and (B) was used alone. Incomparable with the closing, visually equivalent; ○ slight closing is visually observed; △ clear closing is visually observed; x is shown in Table 2 as x.

Further, as for the mechanical strength, the test piece obtained in the above [3] was used, and the Izod impact strength (with notch) was measured in accordance with JIS-K7110.
Table 2 shows the results of the tensile elongation measured according to JIS-K7113.

[0054]

[Table 2]

[5] Evaluation of Solvent Resistance The rod-shaped test piece having a thickness of 1.6 mm for evaluating solvent resistance obtained in the above [3] was subjected to 0.5% strain and then soaked in gauze. Each of the following solvents was placed on a strained portion, covered with a wrap to prevent the solvent from volatilizing, left at 80 ° C. for 24 hours, and visually evaluated for changes in surface appearance and for the occurrence of cracks.

Surfactant A: manufactured by Kao Corporation; Magiclin Surfactant B: manufactured by Shinichi Medico; air conditioner cleaning JE
Tα Gasoline: Idemitsu Kosan Co., Ltd .: Idemitsu Super Zeas Plasticizer: Tokyo Kasei Co., Ltd .; Dioctyl phthalate Cutting oil: Nippon Oil Co., Ltd .; Unisolble EM Observation: No change at all: ◎ Little change: ○ Cloudy or fine cracks observed on the surface: △ Roughness or cracks observed on the surface:
C: Surface dissolution or occurrence of large cracks observed: * These evaluation results are shown in Table 3.

[0057]

[Table 3]

[Comparative Examples 1 to 22] [1] Selection of Component (A) As the atactic polystyrene of the component (A), the four types of styrene resins (a-1) to (a-4) in Example 1 were used. And a styrene resin composition. [2] Selection of the component (C) The styrene polymer having a syndiotactic structure in the styrene polymer chain but having physical properties which do not fall under the definition of the component (B) in the present invention is referred to as (C). Ingredients
Seven types of styrene resins of (c-1) to (c-7) shown in Table 4 below were selected.

[0059]

[Table 4]

[3] Dry Blend of Component (A) and Component (C) and Production of Molded Article The above components (A) and (C) were mixed in a Henschel mixer at a mixing ratio shown in Table 5 below. , And injection molding was performed at a mold temperature of 40 ° C. to produce various test pieces similar to those in Example 1. [4] Evaluation of Formability and Mechanical Strength Using the various test pieces obtained in the above [3], the moldability and the mechanical strength were evaluated in the same manner as in [4] of Example 1.

Table 5 shows the results of these evaluations.

[0062]

[Table 5]

[5] Evaluation of solvent resistance Using the rod-shaped test piece for evaluating solvent resistance obtained in the above [3], the solvent resistance was evaluated in the same manner as in [5] of Example 1.

Table 6 shows the results of these evaluations.

[0065]

[Table 6]

[0066]

According to the molding material of the present invention, when molding a molded article, the melt-kneading step can be omitted, and the dry blend can be immediately supplied to the molding machine for molding. Molding at the molding temperature of atactic polystyrene. Therefore, the time required for molding is shortened, the productivity is improved, and the energy consumption required for molding can be reduced. Further, the molded article obtained in this way is excellent not only in solvent resistance but also in mechanical properties such as impact strength and tensile elongation.

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Claims (4)

[Claims] 1. A styrene polymer having an atactic structure having 10 to 95% by weight, and (B) a melting point of 245 ° C.
A molding material comprising a dry blend of 5 to 90% by weight of a styrene polymer having a syndiotactic structure and having a weight average molecular weight of 200,000 or less. 2. An initial relative crystallinity of a styrene polymer having a syndiotactic structure as a component (B), as measured by a differential scanning calorimeter, is 60% or less.
The molding material according to 1. 3. The molding material according to claim 1 or 2,
A method for producing a molded article molded at a resin temperature of 260 ° C. or lower. 4. A molded article produced by the method for producing a molded article according to claim 3.