JP5470670B2 - Rubber-modified impact-resistant polystyrene resin composition - Google Patents

Description

  The present invention relates to a rubber-modified impact-resistant polystyrene resin whose impact resistance and other performances are improved in a well-balanced manner.

  A copolymer obtained by radical polymerization by adding polybutadiene to a styrene monomer is widely known as an impact-resistant polystyrene resin having improved impact resistance in addition to the excellent properties of polystyrene. As a rubber modifier used for producing this impact-resistant polystyrene-based resin, generally, a cis-1,4 structure obtained by polymerizing 1,3-butadiene using an alkyllithium as a catalyst is 30 to 35%, 1,3-butadiene is polymerized by a low cis polybutadiene (hereinafter, low cis BR) having a vinyl structure of 10 to 20% and a trans-1,4 structure of 50 to 60% and a cobalt, titanium or nickel catalyst. The cis-1,4 structure obtained is 90-98%, the vinyl structure is 1-5%, and the trans-1,4 structure is 1-5%. .

  For example, as a prior art in the past, an impact-resistant polystyrene-based resin containing high cis BR having a specific viscosity has been disclosed (Patent Documents 1 to 3). Further, as an impact-resistant polystyrene-based resin, a rubber component whose rubber component is a rubber mainly composed of high cis BR and whose gel swelling index is 7.0 to 14.0 is disclosed (Patent Document 4). ).

  Further, for example, in Patent Document 5, etc., as a rubber modifier, a high cis-produced with a metallocene catalyst having a cis-1,4 structure of 65 to 95% and a 1,2 structure of 30 to 4%. An impact-resistant polystyrene resin using high vinyl BR has been reported.

  Main applications are home appliances, OA, food packaging materials, etc., and impact resistance is mainly required for physical properties. However, when used in applications such as food packaging materials, ordinary impact-resistant polystyrene resins have the disadvantage that they are inferior in heat resistance and solvent resistance because the three-dimensional structure of polystyrene is an amorphous resin having an attack structure. .

Japanese Unexamined Patent Publication No. 63-172708 JP-A-2-45508 JP-A-5-155937 Japanese Patent Publication No.57-26695 Japanese Patent Laid-Open No. 10-139835

  The present invention improves the heat resistance and solvent resistance, which were the above-mentioned drawbacks, and has improved various physical properties such as reactivity with styrene monomer, impact resistance (Izod DuPont), and glossiness at the same time. An object is to provide a rubbery polymer-containing impact polystyrene resin.

The present invention is a polybutadiene having a rubber-modified impact-resistant polystyrene resin containing a rubber-like polymer grafted with a polystyrene resin, wherein the rubber-like polymer satisfies all of the following (A) to ( D ): A rubber-modified impact-resistant polystyrene-based resin composition characterized by that.
Characteristics of polybutadiene:
(A) vinyl cis polybutadiene containing syndiotactic polybutadiene resin and cis polybutadiene as a matrix;
(B) vinyl cis polybutadiene obtained by graft addition of a polyisoprene polymer to the syndiotactic polybutadiene resin; and
(C) the syndiotactic polybutadiene resin is crystalline particles or / and fibers, aggregates of the fibers ,
(D) The ratio of the syndiotactic polybutadiene to the total amount of the syndiotactic polybutadiene and the cis polybutadiene is 10% by weight or more .

The rubber-modified impact-resistant polystyrene-based resin composition is characterized in that the rubber-modified impact-resistant polystyrene-based resin is a polybutadiene having characteristics that also satisfy the following (D ′) and (E).
(D ′) The ratio of the syndiotactic polybutadiene to the total amount of syndiotactic polybutadiene and cis polybutadiene is 12% by weight or more,
(E) The ratio of the rubbery polymer to the total amount of the styrene monomer and the rubbery polymer when styrene is converted is 7% by weight or more.
The present invention also relates to a rubber-modified impact-resistant polystyrene resin composition characterized in that the syndiotactic polybutadiene resin described above uses the vinyl cis-polybutadiene modified with a polyisoprene polymer.

Further, the present invention provides the above rubbery polymer,
(A) The particles or / and fibers, and aggregates of the fibers are finely dispersed in the matrix polybutadiene with a diameter of 0.2 μm or less. (B) The melting point of the syndiotactic polybutadiene resin is in the range of 170 ° C. to 250 ° C. Ηsp / c is 1.0 to 5.0 (C) The content of the syndiotactic polybutadiene resin is in the range of 1 to 20 parts by mass with respect to the vinyl cis polybutadiene (D) of the matrix polybutadiene. The cis structure content is 80% or more and the weight average molecular weight determined in terms of polystyrene is in the range of 300,000 to 800,000 (E) The intrinsic viscosity ([η]) of the matrix polybutadiene is 1.0 to 5.0, Phenol having ML of 10 to 50, St-cp of 10 to 200, and St-cp / ML of 1 to 10 (F) containing one or more thioether structures as antioxidants The present invention relates to a rubber-modified impact-resistant polystyrene-based resin containing 0.01% by mass to 0.5% by mass of a system antioxidant.

  The present invention also relates to a rubber-modified impact-resistant polystyrene resin composition characterized in that the syndiotactic polybutadiene resin described above uses the vinyl cis-polybutadiene modified with a polyisoprene polymer.

  In the present invention, the polyisoprene polymer is a synthetic polyisoprene, a natural rubber, a modified polyisoprene having a main chain and / or a side chain modified with a functional group, and the like. The present invention relates to an impact polystyrene-based resin composition.

  In addition, the present invention adds (A) a phenolic antioxidant containing at least one thioether structure as an antioxidant and / or a polymerization terminator at the time of production of the rubber-modified styrene resin or at the end of production (B). The present invention relates to a method for producing the rubber-modified impact-resistant polystyrene resin composition, characterized by containing 0.01% by mass to 0.5% by mass of the phenolic antioxidant.

The present invention also relates to the rubber-modified impact-resistant polystyrene resin composition described above, wherein 1 to 50 parts by weight of a flame retardant is contained in the rubber-modified styrene resin composition.

  According to the present invention, various physical properties such as heat resistance, solvent resistance, reactivity with styrene monomers, impact resistance (Izod DuPont), and glossiness of the impact-resistant styrenic resin composition can be improved.

The rubbery polymer of the present invention is polybutadiene having the following characteristics.
Properties of polybutadiene: (A) vinyl cis polybutadiene containing syndiotactic polybutadiene resin and cis polybutadiene as a matrix (B) vinyl cis polybutadiene obtained by grafting polyisoprene polymer to the syndiotactic polybutadiene resin ( C) The syndiotactic polybutadiene resin is crystalline particles or / and fibers, and aggregates of the fibers.

Vinice cis-polybutadiene in the present invention will be described.
(1) The polybutadiene as the matrix component desirably has the following characteristics.
The cis structure content is preferably 80% or more, particularly preferably 90% or more, and it is desirable that the gel content is not substantially contained. Here, the phrase “substantially not containing a gel content” means that the toluene-insoluble content is 0.5% by mass or less.
That is, Mooney viscosity (ML _{1 + 4} 100 ° C., hereinafter abbreviated as “ML”) is preferably 10-50, preferably 10-40.
The toluene solution viscosity (centipoise / 25 ° C., hereinafter abbreviated as “T-cp”) is preferably 10 to 200, more preferably 10 to 100.
Furthermore, it is preferable that T-cp / ML is 1-10.
It is preferable that the weight average molecular weight calculated | required in polystyrene conversion is the range of 300,000-800,000, and an intrinsic viscosity ([(eta)]) is 1.0-5.0.

(2) The syndiotactic-1,2-polybutadiene fiber particles finely dispersed in the matrix, or aggregates thereof, have a melting point of 170 to 250 ° C., preferably 170 to 230 ° C., and ηsp / C is preferably 1.0 to 5.0.
The average monodisperse fiber crystal has a minor axis length of 0.2 μm or less, an aspect ratio of 10 or less, preferably 8 or less, and an average number of monodisperse fiber crystals of 10 or more, preferably 15 It is preferable to form crystal fibers having the above short fiber shape.

  It is preferable that fiber particles and / or fiber particle aggregates of syndiotactic-1,2-polybutadiene are finely dispersed in the matrix.

(3) As a polyisoprene (IR) type polymer, ML viscosity is 10-150, Preferably, it is 15-100.
When the ML viscosity of the polyisoprene polymer is in the above range, the dispersion state of the short fiber crystals of the 1,2-polybutadiene crystal fibers in the styrene monomer / solvent is good when producing the impact-resistant styrene resin. Thus, it becomes easy to improve the controllability of the rubber particles contained in the impact-resistant styrene resin.
It is preferable that the cis structure content of the polyisoprene polymer is 90% or more.
It is preferable that the weight average molecular weight calculated | required in polystyrene conversion of the polyisoprene-type polymer is the range of 300,000-2 million. The graft ratio of the polyisoprene polymer to the syndiotactic polybutadiene polymer is in the range of 5% to 150%.

The ratio of the cis-polybutadiene rubber as the component (1) to the 1,2-polybutadiene crystal fiber as the component (2) is 1,1 of the component (1) with respect to 100 parts by mass of the cis-polybutadiene rubber as the component (1). 1-25 mass parts of 2-polybutadiene crystal fibers are preferable.
Within the above range, the short fiber crystals of 1,2-polybutadiene crystal fibers in the polymerization solution at the time of producing the impact-resistant styrenic resin are likely to be large, resulting in poor dispersibility and 1 part by mass. It is possible to avoid deterioration of physical properties of impact-resistant styrenic resin due to short fiber crystals in the case of a small amount of less, and therefore, the heat resistance and solvent resistance, which are features, are difficult to express, and the reactivity with styrene monomer and impact resistance This is preferable because problems such as deterioration of various properties such as properties (Izod DuPont) and gloss are unlikely to occur.

The proportion of the polyisoprene polymer as the component (3) is preferably 0.01 to 50% by mass of the vinyl cis-polybutadiene composition.
Being within the above range is preferable from the viewpoints of improvement in dispersibility due to aggregation of the 1,2-polybutadiene crystal fiber of the component (2), and suppression of deterioration of various physical properties brought about by the vinyl cis-polybutadiene composition.

  The vinyl cis-polybutadiene is preferably obtained by the following production method, for example.

  In the production of the vinyl cis-polybutadiene composition of the present invention, 1,3-butadiene is generally polymerized using a hydrocarbon solvent. This hydrocarbon solvent is preferably a hydrocarbon solvent having a solubility parameter (hereinafter abbreviated as “SP value”) of 9.0 or less, more preferably a hydrocarbon solvent of 8.4 or less. Examples of the hydrocarbon solvent having a solubility parameter of 9.0 or less include, for example, n-hexane (SP value: 7.2) and n-pentane (SP value: 7) which are aliphatic hydrocarbons and alicyclic hydrocarbons. 0.0), n-octane (SP value: 7.5), cyclohexane (SP value: 8.1), n-butane (SP value: 6.6), and the like. Of these, cyclohexane and the like are preferable.

  The SP values of these solvents are known in documents such as the Rubber Industry Handbook (Fourth Edition, Japan Rubber Association, published on January 20, 1994; page 721).

  By using a solvent having an SP value smaller than 9.0, a dispersion state of short fiber crystals of 1,2-polybutadiene crystal fibers in cis-polybutadiene rubber is formed as expected in the present invention, and impact resistance is improved. It is preferable because various physical properties such as heat resistance, solvent resistance, reactivity with styrene monomer, impact resistance (Izod DuPont), and glossiness of the styrene resin composition can be improved.

  First, 1,3-butadiene and the solvent are mixed, and then the concentration of water in the obtained solution is adjusted. The water content is preferably in the range of 0.1 to 1.0 mol, particularly preferably 0.2 to 1.0 mol, per mol of organoaluminum chloride used as a cis-1,4 polymerization catalyst described later in the solution. It is. In this range, sufficient catalytic activity can be obtained and a suitable cis-1,4 structure content and molecular weight can be obtained, while the generation of gel during polymerization can be suppressed, thereby preventing the gel from adhering to a polymerization tank or the like. It is preferable because the continuous polymerization time can be extended. A known method can be applied as a method of adjusting the moisture concentration. A method of adding and dispersing through a porous filter medium (Japanese Patent Laid-Open No. 4-85304) is also effective.

To the solution obtained by adjusting the concentration of water, organoaluminum chloride is added as one of the cis-1,4 polymerization catalysts. As the organoaluminum chloride, a compound represented by the general formula AlR _n X _3-n is preferably used. Specific examples thereof include diethylaluminum monochloride, diethylaluminum monobromide, diisobutylaluminum monochloride, dicyclohexylaluminum monochloride, Preferred examples include diphenylaluminum monochloride, diethylaluminum sesquichloride and the like. The amount of organoaluminum chloride used is preferably 0.1 mmol or more, more preferably 0.5 to 50 mmol, per 1 mol of the total amount of 1,3-butadiene.

  Next, a soluble cobalt compound is added to the mixed solution to which the organoaluminum chloride is added as another cis-1,4 polymerization catalyst, and 1,3-butadiene is polymerized in cis-1,4. The soluble cobalt compound is soluble in the hydrocarbon solvent or liquid 1,3-butadiene used, or can be uniformly dispersed. For example, cobalt (II) acetylacetonate, cobalt (III) acetylacetonate Cobalt β-diketone complex, cobalt β-keto acid ester complex such as cobalt acetoacetate ethyl ester complex, cobalt octoate, cobalt naphthenate, cobalt benzoate, etc. Examples include cobalt halide complexes such as cobalt pyridine complex and cobalt chloride ethyl alcohol complex. The amount of the soluble cobalt compound used is preferably 0.001 mmol or more, more preferably 0.005 mmol or more per mole of 1,3-butadiene. Further, the molar ratio (Al / Co) of the organoaluminum chloride to the soluble cobalt compound is 10 or more, and particularly preferably 50 or more. In addition to the soluble cobalt compound, an organic carboxylate of nickel, an organic complex of nickel, an organic lithium compound, an organic carboxylate of neodymium, or an organic complex of neodymium can be used.

  The temperature of cis-1,4 polymerization is generally in the temperature range from a temperature exceeding 0 ° C. to 100 ° C., preferably 10 to 100 ° C., more preferably 20 to 100 ° C. The polymerization time (average residence time) is preferably in the range of 10 minutes to 2 hours. It is preferable to perform the cis-1,4 polymerization so that the polymer concentration after the cis-1,4 polymerization is 5 to 26% by mass. The polymerization tank is performed by connecting one tank or two or more tanks. The polymerization is carried out by stirring and mixing the solution in a polymerization tank (polymerizer). As a polymerization tank used for polymerization, a polymerization tank equipped with a high-viscosity liquid stirring apparatus, for example, an apparatus described in JP-B-40-2645 can be used.

  In the production of vinyl cis-polybutadiene of the present invention, during cis-1,4 polymerization, known molecular weight regulators such as non-conjugated dienes such as cyclooctadiene, allene, methylallene (1,2-butadiene), or Α-olefins such as ethylene, propylene and butene-1 can be used. Moreover, in order to further suppress the production | generation of the gel at the time of superposition | polymerization, a well-known gelation inhibitor can be used. In addition, the cis-1,4 structure content of the polymerization product is generally 80% or more, preferably 90% or more, and ML is 10 to 50, preferably 10 to 40, and does not substantially contain a gel content. .

Then, to the cis-1,4 polymerization reaction mixture obtained as described above, an organoaluminum compound represented by the general formula AlR ₃ and carbon disulfide, and if necessary, the soluble cobalt compound are added as 1,2 polymerization catalysts. Then, 1,3-butadiene is subjected to 1,2 polymerization to produce a vinyl cis-polybutadiene composition. At this time, 1,3-butadiene may be added to the polymerization reaction mixture, or unreacted 1,3-butadiene may be reacted without addition. Preferable examples of the organic aluminum compound represented by the general formula AlR ₃ include trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, and triphenylaluminum. The organoaluminum compound is 0.1 mmol or more, especially 0.5 to 50 mmol or more per mol of 1,3-butadiene. The carbon disulfide is not particularly limited, but is preferably one that does not contain moisture. The concentration of carbon disulfide is 20 mmol / L or less, particularly preferably 0.01 to 10 mmol / L. A known phenyl isothiocyanate or xanthate compound may be used as an alternative to carbon disulfide.

  The temperature of 1,2 polymerization is generally in the temperature range of 0 to 100 ° C., preferably 10 to 100 ° C., more preferably 20 to 100 ° C. 1 to 50 parts by weight, preferably 1 to 20 parts by weight of 1,3-butadiene is added to 100 parts by weight of the cis-1,4 polymerization reaction mixture in the polymerization system for carrying out 1,2 polymerization. Thus, the yield of 1,2-polybutadiene during 1,2 polymerization can be increased. The polymerization time (average residence time) is preferably in the range of 10 minutes to 2 hours. It is preferable to perform the 1,2 polymerization so that the polymer concentration after the 1,2 polymerization is 9 to 29% by mass. The polymerization tank is performed by connecting one tank or two or more tanks. The polymerization is carried out by stirring and mixing the polymerization solution in a polymerization tank (polymerizer). As a polymerization tank used for 1,2 polymerization, since the polymer becomes more viscous and easily adheres to the polymer during 1,2 polymerization, a polymerization tank equipped with a high-viscosity liquid stirring device, for example, described in JP-B-40-2645 An apparatus can be used.

In the production of the vinyl cis-polybutadiene composition of the present invention, the vinyl cis-polybutadiene composition is produced by performing cis-1,4 polymerization and then 1,2 polymerization as described above. Adding a polyisoprene-based polymer to the production system of the polybutadiene composition. The effect of the present invention may not be obtained even if it is added after the vinyl cis-polybutadiene composition is produced, for example, during the production of an impact-resistant styrene resin. It is preferable to add a part or all of the polyisoprene polymer at the time of polymerization of vinyl cis-polybutadiene and / or at the end of the polymerization. The polyisoprene polymer is preferably added to the production system before the cis-1,4 polymerization step or before the 1,2 polymerization step, and more preferably when the 1,2 polymerization is performed. .

  Examples of the polyisoprene-based polymer include ordinary synthetic polyisoprene (such as cis-1,4-polyisoprene having a cis structure of 90% or more), natural rubber, liquid polyisoprene, trans-polyisoprene, a functional group having a main chain and / or Alternatively, modified polyisoprene having a modified side chain, such as epoxidized polyisoprene, carboxylated polyisoprene, styrene-isoprene copolymer, styrene-isoprene-styrene terpolymer, hydrogenated polyisoprene, and the like can be mentioned.

  When the polyisoprene polymer is added as described above, in the vinyl cis-polybutadiene composition obtained as described above, the melting point is 1,0 ° C. or higher due to the compatibility effect of the grafted polyisoprene polymer. The dispersibility of 2-polybutadiene in the cis-polybutadiene rubber as a matrix component is significantly improved, and the resulting vinyl-cis-polybutadiene composition has excellent properties.

  The addition of the polyisoprene polymer is preferably performed for 10 minutes to 3 hours after addition, more preferably for 10 minutes to 30 minutes, at any point of time.

In the vinyl cis-polybutadiene production method of the present invention, it is preferable to add an organic peroxide. The organic peroxide is preferably added after the step of cis-1,4 polymerization and before the step of 1,2 polymerization.

Examples of the organic peroxide include peroxyketals, dialkyl peroxides, diacyl peroxides, peresters, hydroperoxides, and ketone peroxides. The molecular weight of the organic peroxide is preferably in the range of 500 or less.

The addition amount of the organic peroxide is preferably in the range of 0.001% by mass to 5% by mass with respect to the added polyisoprene polymer.

  Part or all of the organic peroxide is preferably added before or during the polymerization reaction step of the vinyl cis-polybutadiene.

After the polymerization reaction reaches a predetermined polymerization rate, it is preferable to add a part or all of the sulfur-containing phenol-based antioxidant at the time of polymerization termination or after completion of polymerization.
As the method, for example, after the completion of the polymerization reaction, the polymerization reaction mixture is supplied to a polymerization stop tank, and a large amount of a polar solvent such as alcohol such as methanol and ethanol and water is added to the polymerization reaction mixture. Examples thereof include methods known per se, such as a method of introducing an inorganic acid such as acetic acid and benzoic acid, and a method of introducing hydrogen chloride gas into the polymerization reaction mixture. Subsequently, the vinyl cis-polybutadiene composition produced according to the usual method is separated and recovered, washed and dried to obtain the desired vinyl cis-polybutadiene composition.

  The sulfur-containing phenolic antioxidant is preferably a phenolic antioxidant containing one or more thioether structures.

  Specific examples of phenolic antioxidants having one or more thioether structures include 2,2-thio-diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 2 , 4-Bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine, 2,4-bis [(octylthio) methyl] -ortho -Cresol etc. are mentioned.

  Among them, 2,4-bis [(octylthio) methyl] -ortho-cresol is preferable.

  The addition amount of the antioxidant is preferably 0.01 to 0.5 parts by weight.

  In the method for producing the vinyl cis-polybutadiene composition of the present invention, the remaining unreacted 1,3-butadiene, hydrocarbon solvent and carbon disulfide obtained by separating the obtained vinyl cis-polybutadiene composition are obtained. In general, 1,3-butadiene and hydrocarbon solvents are separated from the mother liquor containing a polymerization reaction mixture by distillation, followed by carbon disulfide adsorption separation or carbon disulfide adduct separation treatment. The carbon is separated and removed, and 1,3-butadiene and hydrocarbon solvent substantially free of carbon disulfide are recovered. Also, carbon disulfide can be obtained by recovering three components from the polymerization reaction mixture mother liquor by distillation, and separating and removing carbon disulfide from the distillate by the adsorption separation or carbon disulfide deposit separation treatment. It is also possible to recover 1,3-butadiene and hydrocarbon solvent which are substantially not contained. The carbon disulfide and hydrocarbon solvent recovered as described above can be reused by mixing newly replenished 1,3-butadiene.

  The rubber-modified styrenic resin composition of the present invention preferably comprises 1 to 25 parts by weight of the above rubbery polymer and 75 to 99 parts by weight of a styrenic resin.

  The rubber-modified styrenic resin composition of the present invention preferably contains 0.001 to 5.0 parts by weight of peroxide.

  Examples of the peroxide include an organic peroxide. Specifically, dicumyl peroxide, 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, 1,1-di-t-butylperoxycyclohexane, 2,2-di- t-butyl peroxybutane, n-butyl 4,4-t-butyl peroxyvalerinate, 2,2-bis (4,4-di-t-butylperoxycyclohexane) propane, 2,2,4-trimethyl Pentylperoxyneodecanate, α-cumylperoxyneodecanate, t-butylperoxyneohexanate, t-butylperoxyacetate, t-butylperoxylaurate, t-butylperoxybenzoate, t-butyl For example, peroxyisophthalate. In addition, peroxides such as hydrogen peroxide and sodium peroxide, and peracids such as peracetic acid and excess acid are also included.

  As a method for producing the rubber-modified impact-resistant polystyrene resin composition of the present invention, a method of polymerizing a styrene monomer in the presence of a rubbery polymer is adopted, and a bulk polymerization method and a bulk suspension polymerization method are economical. This is an advantageous method. Examples of styrene monomers include those conventionally used for producing rubber-modified impact-resistant polystyrene resin compositions such as styrene, α-methylstyrene, alkyl-substituted styrene such as p-methylstyrene, and halogen-substituted styrene such as chlorostyrene. One kind or a mixture of two or more kinds of styrenic monomers are used. Of these, styrene is preferred.

  In addition to the rubber-like polymer, a styrene-butadiene copolymer, ethylene-propylene, ethylene-vinyl acetate, acrylic rubber, etc. may be used in combination within 50% by weight with respect to the rubber-like polymer as necessary during production. it can. Moreover, you may blend the resin manufactured by these methods. Furthermore, you may manufacture by mixing the polystyrene-type resin which does not contain the rubber-modified polystyrene-type resin composition manufactured by these methods. As an example of the bulk polymerization method described above, a rubbery polymer (1 to 25% by weight) is dissolved in a styrene monomer (99 to 75% by weight), and in some cases, a solvent, a molecular weight regulator, a polymerization initiator. Etc. are added to convert the rubber-like polymer into particles dispersed to a styrene monomer conversion rate of 10 to 40%. Until the rubber particles are produced, the rubber phase forms a continuous phase. Furthermore, the polymerization is continued until the conversion to a dispersed phase as a rubber particle (particulation step) (polymerization step) to polymerize to a conversion rate of 50 to 99% to produce a rubber-modified impact-resistant polystyrene resin composition.

The dispersed particles of rubber-like polymer referred to in the present invention (rubber particles produced from matrix polybutadiene in vinyl cis-polybutadiene and fiber particles produced from syndiotactic polybutadiene resin) are contained in an impact-resistant polystyrene resin. The dispersed particles are composed of a rubber-like polymer and a polystyrene-based resin, and the polystyrene-based resin is grafted to the rubber-like polymer or occluded without being grafted. The diameter of the dispersed particles of the rubbery polymer referred to in the present invention is preferably in the range of 1.0 to 5.0 μm.

  The rubber-modified styrenic resin composition preferably contains 1 to 50 parts by weight of a flame retardant.

  Examples of the flame retardant include decabromodiphenyl ether, hexabromobenzene, tetrabromobisphenol A, an oligomer of tetrabromobisphenol A, tribromophenyl-2,3-dibromopropyl ether, hexabromocyclododecane, tetrabromoethane, Halogen flame retardants such as tris (2,3-dibromopropyl) phosphate, chlorinated paraffin, perchlorpentacyclodecane, ammonium phosphate, tricresyl phosphate, totiethyl phosphate, tris (β-chloroethyl) Phosphorus flame retardants such as phosphate, trischloroethyl phosphate, inorganic flame retardants such as red phosphorus, magnesium hydroxide, magnesium hydroxide, zirconium hydroxide, barium metaborate, antimony trioxide, borax And the like, they may be a combination of two or more.

  It may be a batch type or a continuous production method and is not particularly limited.

  In this invention, the raw material solution mainly composed of the styrene monomer and the rubbery polymer is polymerized in a complete mixing reactor. However, in the complete mixing reactor, the raw material solution has a uniform mixed state in the reactor. As long as it is maintained, a stirring blade of a type such as a helical ribbon, a double helical ribbon, or an anchor is preferable. It is preferable that a draft tube is attached to the helical ribbon type stirring blade to further enhance the vertical circulation in the reactor.

  The rubber-modified impact-resistant polystyrene-based resin composition of the present invention includes an antioxidant, a stabilizer such as an ultraviolet absorber, a release agent, a lubricant, a colorant, and various fillers as necessary during and after production. In addition, known additives such as various plasticizers, higher fatty acids, organic polysiloxanes, silicone oils, flame retardants, antistatic agents and foaming agents may be added. The rubber-modified impact-resistant polystyrene resin composition of the present invention can be used for various known molded products, but has excellent heat resistance, solvent resistance, flame resistance, impact strength, tensile strength, etc. -Suitable for injection molding used in industrial applications and extrusion molding used in food packaging materials.

  For example, it can be used for a wide range of applications such as home appliances / industrial use for housings such as color televisions, radio cassettes, word processors, typewriters, facsimiles, VTR cassettes, telephones, and food packaging materials such as containers, trays and films.

The microstructure was performed by infrared absorption spectrum analysis. The microstructure was calculated from the absorption intensity ratio of cis 740 cm ⁻¹ , trans 967 cm ⁻¹ and vinyl 910 cm ⁻¹ .

  [Η] uses a 1 g / L toluene solution, and Canon Fenske viscometer No. 75 was used and measured at a temperature of 30 ° C.

  Toluene solution viscosity (Tcp) was obtained by dissolving 2.28 g of polymer in 50 ml of toluene, and then using a standard solution for calibrating viscometer (JIS Z8809) as a standard solution. 400 was used and measured at 25 ° C.

Mooney viscosity (ML _{1 + 4} , 100 ° C.) was measured according to JIS6300.

St-cp was measured by measuring the solution viscosity at 25 ° C. when 5 g of rubbery polymer was dissolved in 95 g of styrene monomer, and expressed in centipoise (cp).
Graft ratio: 1 g of rubber-modified impact-resistant polystyrene resin is added to 50 ml of a mixed solution of methyl ethyl ketone / acetone = 1/1 (weight ratio) and stirred vigorously for 1 hour to dissolve and swell. Next, the insoluble matter is allowed to settle in a centrifuge, and the supernatant is discarded by decantation. The methyl ethyl ketone / acetone insoluble matter thus obtained was dried under reduced pressure at 50 ° C., cooled in a desiccator and weighed to obtain methyl ethyl ketone / acetone insoluble matter (MEK / AC-insol.g). The graft ratio was calculated from the rubbery polymer amount (Rg) calculated from the rubbery polymer content. Graft ratio = [MEK / AC-insol. (G) -R (g)] × 100 / R (g)

  Swelling degree: 1 g of rubber-modified impact-resistant polystyrene resin is stirred vigorously for 1 hour in 50 ml of toluene, and dissolved and swollen. Next, the insoluble matter is allowed to settle in a centrifuge, and the supernatant is discarded by decantation. The weight of the settled portion (swelled undried weight) was measured, then vacuum-dried at 100 ° C., cooled in a desiccator, weighed, and expressed as a weight ratio during swelling / drying.

  Rubber particle diameter: A rubber-modified impact-resistant polystyrene-based resin composition is dissolved in dimethylformamide, and only a polystyrene portion that forms a matrix in the resin is dissolved. A TA-2 type was used to disperse the electrolyte in the solvent consisting of the solvent dimethylformamide and the dispersant ammonium thiocyanate, and the resulting volume average particle size was defined as the rubber particle size.

Izod impact strength: Measured according to JIS K7110 (notched).
Dupont impact strength: indicated by 50% fracture energy by a DuPont drop weight tester.

  Gloss: Gloss was measured according to JIS Z8742 (incident angle 60 °).

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. In the examples and comparative examples, the physical properties of the rubber rubber of the vinyl cis-polybutadiene composition, and the physical properties of the resulting silica compound rubber composition for tire and the physical properties of the vulcanizate were measured as follows. .
(1) Content of 1,2 polybutadiene crystal fiber : The remainder of the extraction of 2 g of vinyl cis-polybutadiene composition by boiling with a Soxhlet extractor in 200 ml of n-hexane for 4 hours is shown in parts by weight.
(2) Melting point of 1,2 polybutadiene crystal fiber : The boiling n-hexane extraction remainder was determined by the peak temperature of the endothermic curve by a differential scanning calorimeter (DSC).
(3) Crystal fiber form : The vinyl cis-polybutadiene composition was vulcanized with sulfur monochloride and carbon disulfide, and the vulcanized product was cut into ultra-thin sections and osmium tetrachloride vaporized to give the rubber content of vinyl cis-polybutadiene. The double bond was stained and observed with a transmission electron microscope.
(4) Microstructure of rubber in the vinyl cis-polybutadiene composition ; the analysis was performed by infrared absorption spectrum analysis. The microstructure was calculated from the absorption intensity ratio of cis 740 cm ⁻¹ , trans 967 cm ⁻¹ and vinyl 910 cm ⁻¹ .
(5) Viscosity of toluene solution of rubber in vinyl cis-polybutadiene composition ; Viscosity of 5 wt% toluene solution at 25 ° C. was measured and expressed in centipoise (cp).
(6) [η] of rubber content in vinyl-cis-polybutadiene composition ; boiling n-hexane soluble content was collected by drying and measured with a toluene solution at a temperature of 30 ° C.
(7) Mooney viscosity ; a value measured at 100 ° C. according to JIS K6300.
(8) IR graft ratio The graft ratio indicating the graft reactivity of IR to SPB was measured by the following method.
(IR component analysis)
Using n-hexane insoluble matter (HI), quantitative analysis of the amount of IR contained in the HI component was performed from the peak intensity of the methyl group in the vicinity of 1375 cm ⁻¹ of the infrared absorption spectrum.
(Analysis of SPB component)
Using n-hexane insoluble matter (HI), quantitative analysis of the amount of SPB contained in the HI component was performed from the endothermic peak area of SPB by DSC.
IR graft ratio (%): Ratio of IR incorporated in SPB
= IR component amount in HI / SPB component amount in HI × 100

Examples 1-7 (Comparative Examples 1-7)
In a 30-liter stainless steel reactor equipped with a stirrer, substituted with nitrogen gas, a solution of 1.6 kg of 1.3-butadiene in 18 kg of dehydrated cyclohexane / n-hexane (50/50) was added, 4 mmol of cobalt octoate, diethyl 84 mmol of aluminum chloride and 70 mmol of 1.5-cyclooctadiene were mixed and stirred at 25 ° C. for 30 minutes to carry out cis polymerization. The polymer obtained had an ML of 33, a Tcp of 59, a microstructure of 1,2 structure of 0.9%, a trans-1,4 structure of 0.9%, and a cis-1,4 structure of 98.2%. After cis polymerization, 3% by mass of polyisoprene (IR: Mw = 97.7 × 10 ⁴ ) which is an unsaturated polymer substance (percentage of the obtained vinyl cis polybutadiene rubber) is added to the resulting polymerization product liquid, Stirring was performed at 25 ° C. for 1 hour. Immediately thereafter triethyl the polymerization solution aluminum 90mmol and carbon disulfide 50 mmol, further 1,1 ^'- di - and (Tert-butylperoxy) -3,3,5-trimethylcyclohexane (0.1% by weight relative to IR) was added The mixture was further stirred for 60 minutes at 25 ° C. to carry out 1,2 polymerization. After completion of the polymerization, the polymerization product solution was added to 18 L of methanol containing 1% by mass of 4,6-bis (octylthiomethyl) -o-cresol (adjusted so that 0.1 wt% was contained in the VCR). The polymer was precipitated and precipitated, and the rubbery polymer was separated, washed with methanol, and vacuum dried at room temperature. The yield of vinyl cis-polybutadiene rubber thus obtained was 80%. Thereafter, the vinyl cis-polybutadiene rubber was treated with boiling n-hexane, and the insoluble and soluble components were separated and dried.
The resulting boiling n-hexane soluble polymer had an ML of 32, a Tcp of 57, a Tcp / ML relationship of about 1.8, a microstructure of 1.0% 1,2 (vinyl) structure, trans-1, The four structures were 0.9% and the cis-1,4 structure was 98.1%. The polystyrene-reduced mass average molecular weight was 40 × 10 ⁴ and [η] was 1.7. On the other hand, ηsp / c of the boiling n-hexane insoluble polymer was 1.5, and the graft ratio indicating IR graft reactivity was 23%. The short fiber crystals contained in the vinyl-cis polybutadiene rubber are highly uniform and dispersed. The number of short dispersed fiber crystals having a short axis length of 0.2 μm or less is 100 or more, the aspect ratio is 10 or less, and the melting point is 202. ° C.

  A 1.5 liter autoclave with a stirrer was replaced with nitrogen gas, and styrene (475 g) and the above polymer (25 g: 5 parts by weight as rubber content) were added and dissolved. Next, 0.15 g of n-dodecyl mercaptan was added, and prepolymerization was performed for 1 hour and a half while stirring at 135 ° C. under the conditions shown in Table 3 until the conversion of styrene reached 30%. Next, 500 ml of a 0.5 wt% polyvinyl alcohol aqueous solution was poured into this prepolymerized solution, and 1.0 g (0.2 parts by weight) of benzoyl peroxide and 1.0 g (0.2 parts by weight) of dicumyl peroxide were added. In addition, polymerization was carried out continuously with stirring at 100 ° C. for 2 hours, 125 ° C. for 3 hours, and 140 ° C. for 2 hours. After cooling to room temperature, the bead polymer was filtered from the polymerization reaction mixture, washed with water and dried. This was pelletized with an extruder to obtain 450 g of an impact-resistant polystyrene resin. In addition, regarding the addition method of a flame retardant, the predetermined amount was added at the time of pelletization with an extruder as needed. The obtained rubber-modified impact-resistant polystyrene resin composition was injection-molded and sheet-molded to prepare test pieces for measuring physical properties, and the physical properties were measured. The results are shown in Tables 1-2.

Claims (8)

A rubber-modified impact-resistant polystyrene resin containing a rubber-like polymer grafted with a polystyrene resin, wherein the rubber-like polymer is polybutadiene having characteristics satisfying all of the following (A) to ( D ): A rubber-modified impact-resistant polystyrene-based resin composition.
Characteristics of polybutadiene:
(A) vinyl cis polybutadiene containing syndiotactic polybutadiene resin and cis polybutadiene as a matrix;
(B) vinyl cis polybutadiene obtained by graft addition of a polyisoprene polymer to the syndiotactic polybutadiene resin; and
(C) the syndiotactic polybutadiene resin is crystalline particles or / and fibers, aggregates of the fibers ,
(D) The ratio of the syndiotactic polybutadiene to the total amount of the syndiotactic polybutadiene and the cis polybutadiene is 10% by weight or more .   The rubber-modified impact-resistant polystyrene-based resin composition according to claim 1, wherein the rubber-modified impact-resistant polystyrene-based resin is polybutadiene having a characteristic that also satisfies the following (D ') and (E):
(D ') The ratio of the syndiotactic polybutadiene to the total amount of syndiotactic polybutadiene and cis polybutadiene is 12% by weight or more;
(E) The ratio of the rubbery polymer to the total amount of the styrene monomer and the rubbery polymer when styrene is converted is 7% by weight or more. The rubber-modified impact-resistant polystyrene-based resin according to claim 1 or 2 , wherein the rubber-modified impact-resistant polystyrene-based resin contains rubber particles and / or fiber particles grafted with vinyl cis-polybutadiene and styrene. Composition. The rubber-like impact resistance according to any one of claims 1 to 3 , wherein the rubber-like polymer is polybutadiene having characteristics satisfying all of the following (A) to (F): Polystyrene resin composition.
(A) The particles or / and fibers and the aggregates of the fibers are finely dispersed in the matrix polybutadiene with a diameter of 0.2 μm or less,
(B) The melting point of the syndiotactic polybutadiene resin is in the range of 170 ° C to 250 ° C, and ηsp / c is 1.0 to 5.0,
(C) The content of the syndiotactic polybutadiene resin is in the range of 1 to 20 parts by mass with respect to vinyl cis-polybutadiene,
(D) The cis structure content of the matrix polybutadiene is 80% or more, and the weight average molecular weight determined in terms of polystyrene is in the range of 300,000 to 800,000.
(E) Intrinsic viscosity ([η]) of the matrix polybutadiene is 1.0 to 5.0, ML is 10 to 50, St-cp is 10 to 200, and St-cp / ML is 1 to 10, as well as,
(F) A rubber-modified impact-resistant polystyrene resin characterized by containing 0.01% by mass to 0.5% by mass of a phenolic antioxidant containing at least one thioether structure as an antioxidant. A rubber-modified impact-resistant polystyrene resin composition, wherein the syndiotactic polybutadiene resin according to any one of claims 1 to 4 is the vinyl-cis polybutadiene grafted with a polyisoprene polymer. . The polyisoprene polymer according to any one of claims 1 to 5 is any one of synthetic polyisoprene, natural rubber, and modified polyisoprene in which a main chain and / or a side chain is modified with a functional group. A rubber-modified impact-resistant polystyrene-based resin composition. (A) a phenolic antioxidant containing at least one thioether structure as an antioxidant and / or a polymerization terminator is added at the time of production of the rubber-modified styrenic resin or at the end of production; and
The rubber-modified impact-resistant polystyrene resin composition according to any one of claims 1 to 6 , wherein (B) the phenol-based antioxidant is contained in an amount of 0.01% by mass to 0.5% by mass. Production method.   The rubber-modified impact-resistant polystyrene resin composition according to any one of claims 1 to 7, wherein the rubber-modified styrene resin composition contains 1 to 50 parts by weight of a flame retardant.