JP2009256502A - Styrene-based resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a styrene-based resin composition which gives a molded product that has such excellent flame retardancy and mechanical strengths as is little in the deterioration thereof and which is rich in the low-temperature moldability and recyclability. <P>SOLUTION: The styrene-based resin composition, containing a styrene-based resin (A) and a flame retardant (B), is characterized in that the above styrene-based resin (A) contains a resin in which a multibranched macromonomer (a1) having a double bond at the branch terminal and a styrene-based monomer (a2) are copolymerized and which has a melt mass flow rate (MFR) at 200°C of 4.0-10.0 g/10 min. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention contains a specific styrenic resin and a flame retardant, has a good flow in the molten state and is excellent in moldability, and has good flame retardancy and mechanical strength of the obtained molded product, and deterioration thereof. The present invention relates to an environmentally friendly styrenic resin composition with a small amount of odor.

  It is said that various molded articles made of plastic are preferably made of a thermoplastic resin composition that is rich in moldability at low temperatures and material recyclability from the viewpoint of reducing environmental impact and saving energy. . Molding at a lower temperature not only reduces energy costs, but also suppresses deterioration of the resin and molded product due to thermal history. In addition, material recycling is a process in which defective products, half-finished products, used molded products, etc. generated during molding are melted again and processed into the desired molded products, so the inherent performance deteriorates due to heat. It is an essential condition that it is difficult to do.

  Expanded polystyrene made from polystyrene, a thermoplastic resin, is widely used not only for industrial use but also for household use as a food tray and cushioning material from the viewpoint of ease of processing into any shape and light weight. The system is being completed. In addition, as a foam board material whose amount of use is increasing as a heat insulating material in recent energy-saving high airtight and high heat insulation houses, polystyrene having excellent foamability is used as a basic resin (for example, Patent Document 1). reference.).

  Since polystyrene is a flammable resin, it is generally used together with a flame retardant. In particular, halogen flame retardants have been widely used because of their excellent compatibility with polystyrene. Although the halogen-based flame retardant has an excellent flame retardant effect, the flame retardant decomposes upon heating to generate hydrogen halide. The generated hydrogen halide causes deterioration (decomposition) of polystyrene, which in turn causes deterioration of mechanical strength and the like of the molded product. Therefore, to reduce the amount of halogenated flame retardant as much as possible and to be molded at a low temperature, the only way to reduce the molecular weight is to ensure the flowability of polystyrene and enable low temperature processing. The lowering of the molecular weight leads to insufficient mechanical strength of the molded product, and there is a trade-off between maintaining the physical properties of the molded product and low temperature processability. In order to address these issues, it is considered to maintain strength of moldability by blending low molecular weight polystyrene and high molecular weight polystyrene, but this is not a practical level (for example, patents) Reference 2).

JP 2004-161868 A JP 2005-29618 A

  In view of the above circumstances, the problem to be solved by the present invention is excellent in moldability, good flame retardancy and mechanical strength of the obtained molded product, and less deteriorated, low temperature moldability and recyclability. An object of the present invention is to provide a styrenic resin composition that is rich in styrene.

  As a result of intensive research to solve the above problems, the present inventors have reduced the use ratio of the flame retardant used for conventional polystyrene by using a styrene resin having a specific structure. However, it is possible to obtain a molded product having flame retardancy that can be sufficiently used, and because the flowability of the composition is good, low-temperature molding processing is possible, and the physical properties of the molded product are not significantly impaired even by heating. The present inventors have found that material recycling is possible and have completed the present invention.

  That is, the present invention is a styrene resin composition containing a styrene resin (A) and a flame retardant (B), wherein the styrene resin (A) has a multi-branched shape having a double bond at a branch end. It contains a resin obtained by copolymerizing a macromonomer (a1) and a styrene monomer (a2), and has a melt mass flow rate (MFR) at 200 ° C. of 4.0 to 10.0 g / 10 min. A styrenic resin composition is provided.

  The styrenic resin composition of the present invention has good flame retardancy and mechanical strength of the resulting molded product, and can be molded and extruded at low temperature. Therefore, since the deterioration of physical properties due to the heat history is low, it is possible to suitably cope with reduction of flame retardant, reduction of power cost of molding extruder, and material recycling, and the environmental load reduction effect is high.

The present invention is described in detail below.
[Styrene resin (A)]
The styrene resin (A) used in the present invention is a multi-branched resin obtained by copolymerizing a multi-branched macro monomer (a1) having a double bond at a branch end and a styrene monomer (a2). It is a styrenic resin contained as an essential component. In addition, the styrene resin (A) used in the present invention is produced at the same time as the copolymerization with the multibranched resin obtained by copolymerizing the multibranched macromonomer (a1) and the styrene monomer (a2). You may contain the homopolymer (linear resin) of a styrene-type monomer (a2). Further, linear resins produced separately in advance may be mixed with a multi-branched resin obtained by copolymerizing the multi-branched macromonomer (a1) and the styrene monomer (a2).

  Regarding the fluidity of the styrene-based resin (A), it is excellent in balance with low-temperature extrusion moldability, flame retardant decomposition suppression, appearance of the resulting molded product, and strength, and enables material recycling at 200 ° C. It is essential that the melt mass flow rate (MFR) is 4.0 to 10.0 g / 10 min, and preferably 5.0 to 8.0 g / min.

[GPC-MALLS, slope of logarithmic graph of styrene resin (A)]
When the molecular weight of the styrene resin (A) used in the present invention is measured by GPC-MALLS (MALLS: multi-angle light scattering detector), it is possible to obtain the relationship between the molecular weight and the inertia radius (particle diameter) in addition to the molecular weight. . For the styrene resin (A), the gradient in the region of molecular weight 250,000 to 10 million in the logarithmic graph with the horizontal axis representing the molecular weight of the resin determined from GPC-MALLS and the vertical axis representing the radius of inertia is the strength and molding process. It is most preferable that it is 0.35-0.45 from the point which expresses property with the outstanding balance. When the slope is larger than 0.45, the physical properties are closer to those of linear polystyrene. Conversely, when the slope is smaller than 0.35, the fluidity is lowered due to the increase in the molecular weight accompanying the increase in the degree of branching, which affects the molding processability. Sometimes.

[Molecular weight of styrene resin (A)]
In the styrene resin (A) used in the present invention, the weight average molecular weight determined from GPC-MALLS is preferably 150,000 to 400,000, more preferably 180,000 to 3030, in terms of the balance between low-temperature extrusion moldability, strength and processability. Ten thousand. When the weight average molecular weight is 150,000 or less, the strength tends to decrease. When the weight average molecular weight is 400,000 or more, the viscosity of the resin increases, and the extrusion moldability at low temperatures tends to be difficult.

[Multi-branched macromonomer (a1)]
As the hyperbranched macromonomer (a1) used in the present invention, a styrene resin (A) excellent in processability intended by the present invention can be easily obtained, in particular, the weight average molecular weight of the hyperbranched resin. The weight average molecular weight (Mw) having a plurality of branches and having a plurality of polymerizable double bonds at the tip thereof is preferably 1,000 to 15,000, More preferably, it is a 2,000-9,000 macromonomer.

  It is essential that the tip of the multi-branched macromonomer (a1) has two or more polymerizable double bonds per molecule. A double bond is preferred. The content of the polymerizable double bond is preferably in the range of 0.1 to 5.5 mmol, and more preferably in the range of 0.5 to 3.5 mmol, per 1 g of the macromonomer. When the amount is less than 0.1 mmol, it is difficult to obtain a high-molecular-weight multi-branched resin. When the amount exceeds 5.5 mmol, the molecular weight of the multi-branched resin tends to increase excessively.

[Multi-branched macromonomer (a1-i)]
The multibranched macromonomer (a1) that can be used in the present invention includes a branched structure formed by repeating a structural unit having an ester bond, an ether bond or an amide bond, and two or more polymerizable groups in one molecule at the branch end. A multi-branched macromonomer (a1-i) having a double bond can be mentioned.

  In the multibranched macromonomer (a1-i-1) in which a structural unit having an ester bond is repeatedly formed to form a branched structure, the carbon atom adjacent to the carbonyl group of the ester bond forming the molecular chain is a quaternary carbon atom. A preferred embodiment is one in which a polymerizable double bond such as a vinyl group or an isopropenyl group is introduced into a multi-branched polyester polyol. Introducing a polymerizable double bond into a multi-branched polyester polyol can be carried out by an esterification reaction or an addition reaction. As the above multi-branched polyester polyol, “Boltorn H20, H30, H40” manufactured by Perstorp is commercially available.

  In the multi-branched polyester polyol, a substituent may be introduced into a part of the hydroxy group in advance by an ether bond or other bond, and a part of the hydroxy group may be oxidized or other reaction. It may be denatured. Further, in the hyperbranched polyester polyol, a part of the hydroxy group may be esterified in advance.

  Examples of the multi-branched macromonomer (a1-i-1) include a compound having one or more hydroxy groups, a carbon atom adjacent to the carboxy group being a quaternary carbon atom, and two or more hydroxy groups. It is obtained by reacting a monocarboxylic acid having a multi-branched polymer, and then reacting the hydroxyl group, which is a terminal group of the polymer, with an unsaturated acid such as acrylic acid or methacrylic acid or an acrylic compound containing an isocyanate group. Things. In addition, about the multibranched polymer which formed the branched structure by repeating the structural unit which has an ester bond, "Angew.Chem.Int.Ed.Engl.29" p138-177 (1990) by Mr. Tamalia etc. Are listed.

  Examples of the compound having at least one hydroxy group include a) aliphatic diol, alicyclic diol, or aromatic diol, b) triol, c) tetraol, d) sugar alcohols such as sorbitol and mannitol, e) anne Hydroenenea-heptitol or dipentaerythritol, f) α-alkyl glucoside such as α-methyl glycoside, g) monofunctional alcohol such as ethanol, hexanol, h) alkylene oxide having a weight average molecular weight of at most 8,000, or The hydroxy group containing polymer etc. which were produced | generated by making the derivative and the hydroxyl group in 1 or more types of compounds selected from any of said a) -g) react can be mentioned.

  Examples of the a) aliphatic diol, alicyclic diol and aromatic diol include, for example, 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1, 6-hexanediol, polytetrahydrofuran, dimethylolpropane, neopentylpropane, 2-propyl-2-ethyl-1,3-propanediol, 1,2-propanediol, 1,3-butanediol, diethylene glycol, triethylene glycol , Polyethylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol; cyclohexanedimethanol, 1,3-dioxane-5,5-dimethanol; 1,4-xylylenediethanol, 1-phenyl-1,2-ethanediol Etc. . Examples of the b) triol include trimethylolpropane, trimethylolethane, trimethylolbutane, glycerol, 1,2,5-hexanetriol, 1,3,5-trihydroxybenzene, and the like. Examples of c) tetraol include pentaerythritol, ditrimethylolpropane, diglycerol, and ditrimethylolethane.

  Examples of the monocarboxylic acid in which the carbon atom adjacent to the carboxyl group is a quaternary carbon atom and having two or more hydroxy groups include, for example, dimethylolpropionic acid, α, α-bis (hydroxymethyl) butyric acid, α , Α, α-tris (hydroxymethyl) acetic acid, α, α-bis (hydroxymethyl) valeric acid, α, α-bis (hydroxymethyl) propionic acid, and the like. By using the monocarboxylic acid, the ester decomposition reaction is suppressed and a multibranched polyester polyol can be formed.

  Further, it is preferable to use a catalyst when producing the multi-branched polyester polyol. Examples of the catalyst include organic tins such as dialkyltin oxide, halogenated dialkyltin, dialkyltin biscarboxylate, and stannoxane. Examples thereof include compounds, titanates such as tetrabutyl titanate, organic sulfonic acids such as Lewis acid and p-toluenesulfonic acid.

Examples of the multibranched macromonomer (a1-i-2) in which a structural unit having an ether bond is repeated to form a branched structure include, for example, a cyclic ether having one or more hydroxy groups in a compound having one or more hydroxy groups The compound is reacted to form a hyperbranched polymer, and then the terminal hydroxyl group of the polymer is unsaturated acid such as acrylic acid or methacrylic acid, isocyanate group-containing acrylic compound, halogen such as 4-chloromethylstyrene And those obtained by reacting methyl styrene. Further, as a method for producing the multi-branched polymer, a compound having one or more hydroxy groups, two or more hydroxy groups and a halogen atom, -OSO ₂ OCH ₃ or -OSO ₂ is used based on Williamson's ether synthesis method. A method of reacting with a compound containing CH ₃ is also useful.

As the compound having one or more hydroxy groups, any of those mentioned above can be used, and as the cyclic ether compound having one or more hydroxy groups, for example, 3-ethyl-3- (hydroxymethyl) Examples include oxetane, 2,3-epoxy-1-propanol, 2,3-epoxy-1-butanol, and 3,4-epoxy-1-butanol. The compounds having one or more hydroxy groups used in the Williamson ether synthesis method may be those described above, but aromatic compounds having two or more hydroxy groups bonded to an aromatic ring are preferred. Examples of the compound include 1,3,5-trihydroxybenzene, 1,4-xylylenediethanol, 1-phenyl-1,2-ethanediol and the like. Examples of the compound containing two or more hydroxy groups and a halogen atom, —OSO ₂ OCH ₃ or —OSO ₂ CH ₃ include, for example, 5- (bromomethyl) -1,3-dihydroxybenzene, 2-ethyl-2. -(Bromomethyl) -1,3-propanediol, 2-methyl-2- (bromomethyl) -1,3-propanediol, 2- (bromomethyl) -2- (hydroxymethyl) -1,3-propanediol, etc. Can be mentioned. In addition, when manufacturing the said hyperbranched polymer, it is preferable to use a normal catalyst, and examples of the catalyst include BF ₃ diethyl ether, FSO ₃ H, ClSO ₃ H, HClO _{4 and the} like. Can do.

  In addition, examples of the multi-branched macromonomer (a1-i-3) in which a structural unit having an amide bond is repeated to form a branched structure include those having an amide bond in a repeating structure via a nitrogen atom in the molecule. A typical example is the generation 2.0 (PAMAM dentrimer) manufactured by Dentorite.

[Polymerization method of hyperbranched macromonomer (a1) and styrene monomer (a2)]
By copolymerizing the multi-branched macromonomer (a1) and the styrene monomer (a2), a multi-branched resin and a linear resin (polystyrene) and a low-branched resin that are simultaneously generated depending on polymerization conditions A resin mixture which is a mixture is obtained. At this time, by using the above-mentioned multibranched macromonomer (a1) in a ratio of preferably 50 ppm to 1%, more preferably 100 ppm to 3000 ppm, based on the styrene monomer (a2), the production of a multibranched resin is obtained. Is easy, it is easy to suppress gelation, and the styrene resin (A) used in the present invention can be obtained efficiently.

  In particular, in order to efficiently obtain the styrene resin (A) having a melt mass flow rate (MFR) at 200 ° C. of 4.0 to 10.0 g / 10 min used in the present invention, the entire polymerization temperature is set high. It is desirable to do. Specifically, in bulk polymerization or solution polymerization, it is desirable to set the temperature after the middle stage of polymerization (polymerization rate of 25% or higher) to 145 ° C. or higher. Further, in order to obtain a target styrenic resin (A) having a molecular design, it is also possible to add an organic solvent amount or a chain transfer agent and synthesize the reaction system efficiently.

  Various commonly used polymerization methods of styrene monomers can be applied to the polymerization reaction. The polymerization method is not particularly limited, but bulk polymerization, suspension polymerization, or solution polymerization is preferable. Among them, continuous bulk polymerization is particularly preferable from the viewpoint of production efficiency.For example, by performing continuous bulk polymerization incorporating one or more stirred reactors and a tubular reactor in which a plurality of mixing elements having no moving parts are fixed. An excellent resin can be obtained. Although thermal polymerization can be performed without using a polymerization initiator, it is preferable to use various radical polymerization initiators. Moreover, what is used for manufacture of a normal polystyrene can be used for polymerization adjuvants, such as a suspending agent and an emulsifier required for superposition | polymerization.

  In order to reduce the viscosity of the reaction product in the polymerization reaction, an organic solvent may be added to the reaction system. Examples of the organic solvent include toluene, ethylbenzene, xylene, acetonitrile, benzene, chlorobenzene, dichlorobenzene, and anisole. , Cyanobenzene, dimethylformamide, N, N-dimethylacetamide, methyl ethyl ketone and the like. In particular, when it is desired to increase the amount of the hyperbranched macromonomer, it is preferable to use an organic solvent from the viewpoint of suppressing gelation. Thereby, the addition amount of the multibranched macromonomer shown above can be increased dramatically, and gelation hardly occurs.

  The radical polymerization initiator is not particularly limited. For example, 1,1-bis (t-butylperoxy) cyclohexane, 2,2-bis (t-butylperoxy) butane, 2,2-bis (4 , 4-di-butylperoxycyclohexyl) propane and other peroxyketals, cumene hydroperoxide, hydroperoxides such as t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, di Dialkyl peroxides such as -t-hexyl peroxide, diacyl peroxides such as benzoyl peroxide and disinamoyl peroxide, t-butyl peroxybenzoate, di-t-butyl peroxyisophthalate, t-butyl peroxide Pao such as oxyisylpropyl monocarbonate Siesters, N, N′-azobisisobutylnitrile, N, N′-azobis (cyclohexane-1-carbonitrile), N, N′-azobis (2-methylbutyronitrile), N, N′-azobis ( 2,4-dimethylvaleronitrile), N, N′-azobis [2- (hydroxymethyl) propionitrile] and the like, and these can be used alone or in combination.

  Furthermore, you may add a chain transfer agent so that the molecular weight of the resin mixture obtained may not become too large. As the chain transfer agent, either a monofunctional chain transfer agent having one chain transfer group or a polyfunctional chain transfer agent having a plurality of chain transfer groups can be used. Examples of the monofunctional chain transfer agent include alkyl mercaptans and thioglycolic acid esters. Polyfunctional chain transfer agents include ethylene glycol, neopentyl glycol, trimethylol propane, pentaerythritol, dipentaerythritol, tripentaerythritol, sorbitol and the like, hydroxy groups in polyhydric alcohols such as thioglycolic acid or 3-mercaptopropionic acid. And the like esterified with.

  Examples of the styrenic monomer (a2) that can be used in the present invention include styrene and derivatives thereof; for example, styrene, methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, butylstyrene, Examples thereof include alkyl styrene such as hexyl styrene, heptyl styrene and octyl styrene, halogenated styrene such as fluoro styrene, chloro styrene, bromo styrene, dibromo styrene and iodo styrene, nitro styrene, acetyl styrene and methoxy styrene.

[Flame Retardant (B)]
The flame retardant (B) used in the present invention is not particularly limited as long as it is generally used, but one that can be easily kneaded with the styrene resin (A) is preferable.

  Specific examples of the flame retardant (B) include halogen-based flame retardants. Brominated flame retardants such as brominated products of aliphatic or alicyclic hydrocarbons such as hexabromocyclododecane, hexabromobenzene, ethylenebispentabromodiphenyl, decabromodiphenylethane, decabromodiphenyl ether, octabromodiphenyl ether, 2, 3 -Brominated aromatic compounds such as dibromopropylpentabromophenyl ether, tetrabromobisphenol A, tetrabromobisphenol A bis (2,3-dibromopropyl ether), tetrabromobisphenol A (2-bromoethyl ether), tetrabromo Brominated bisphenols such as bisphenol A diglycidyl ether, adducts of tetrabromobisphenol A diglycidyl ether and tribromophenol and their derivatives, tetrabromo Brominated bisphenol derivatives oligomers such as Sphenol A polycarbonate oligomer, epoxy oligomer of adduct of tetrabromobisphenol A diglycidyl ether and brominated bisphenol, ethylenebistetrabromophthalimide, bis (2,4,6-tribromophenoxy) ) Brominated aromatic compounds such as ethane, brominated acrylic resins, ethylenebisdibromonorbornane dicarboximide and the like. Examples of the chlorinated flame retardant include chlorinated aliphatic compounds such as chlorinated paraffin, chlorinated naphthalene, and perchloropentadecane, chlorinated aromatic compounds, and chlorinated alicyclic compounds. These compounds can be used alone or in combination of two or more.

  Examples of flame retardants other than the above include, for example, tricresyl phosphate, triphenyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, resorcinol-bis- (diphenyl phosphate), 2-ethylhexyl diphenyl phosphate, dimethyl Phosphorus flame retardants such as methyl phosphate, triallyl phosphate, tris-3-chloropropyl phosphate, trischloroethyl phosphate, trisdichloropropyl phosphate, tris β-chloropropyl phosphate, tris (tribromophenyl) phosphate, tris (dibromophenyl) ) Phosphate, tris (tribromoneopentyl) phosphate, diethyl-N, N-bis (2-hydroxyethyl) amino Halogen-containing phosphoric ester flame retardants such chill phosphate phenate, aluminum hydroxide, antimony trioxide, antimony pentoxide, and can also be used such as inorganic flame retardants such as magnesium hydroxide.

  About the compounding quantity of a flame retardant (B), although it is an item which should be adjusted with the kind etc. of flame retardant (B) to be used, in general linear or a low-branched polystyrene resin, with respect to 100 mass parts Usually 0.1 to 15 parts by mass, preferably 2 to 10 parts by mass, but the styrene resin (A) used in the present application is compared with a general polystyrene resin having the same molecular weight. Since the fluidity at the time of melting is high, it is possible to reduce the heat generated during extrusion melting, and furthermore, the decomposition of the flame retardant can be suppressed from the point that the extrusion temperature can be lowered by about 10 ° C. It is not necessary to add more flame retardant (B) than necessary, for example, flame retardant that can be used sufficiently by simply blending 1.5 to 9 parts by mass with respect to 100 parts by mass of styrene resin (A) It shows sex.

[Other additives]
In the styrene resin composition of the present invention, any other additive can be appropriately blended as necessary within a range not inhibiting the effects of the present invention. The type of additive is not particularly limited. For example, phosphoric acid ester compounds, silica, talc, wollastonite, calcium silicate, kaolin, mica, clay, zinc oxide, calcium carbonate and other inorganic substances, stearic acid, sodium stearate , Auxiliary agents such as barium stearate, magnesium stearate, liquid paraffin, olefin wax, stearylamide compound, phenolic antioxidant, phosphorus stabilizer, light resistance stabilizer, hydrotalcite, antistatic agent, pigment -Addition of coloring agents such as dyes is also possible.

  Furthermore, other resin compositions can be appropriately blended with the styrene resin composition of the present invention as long as the effects of the present invention are not impaired. Examples of the other resin composition include rubber-containing polystyrene (HIPS), styrene-butadiene copolymer, styrene-acrylic resin, and styrene-methacrylic resin.

[Method of manufacturing molded product]
The blending method of the styrenic resin (A) and the flame retardant (B), and other additives is not limited, but is dry blended in advance and melt kneaded using an extruder. It is desirable to form a pellet by using the pellet.

  In the relationship between normal straight-chain or low-branched polystyrene and the specific styrene resin (A) used in the present application, the styrene resin (A) contains a polymer whose molecular structure is close to a circle. Therefore, it exhibits higher fluidity than ordinary polystyrene. The MFR of the mixture of multi-branched polystyrene and linear polystyrene already provided by the present inventor in Japanese Patent Application Laid-Open No. 2005-053939 is 0.5 to 3.5 g / min. It is. The molding temperature of the mixture is preferably 210 ° C. or higher in view of the relationship between melt viscosity and extrusion system internal pressure. On the other hand, since the styrene resin (A) used in the present application has increased MFR by changing the temperature or the like in the polymerization process as described above, the melt kneading temperature and molding temperature of the styrene resin (A) are adjusted. It can be as low as less than 210 ° C. In addition, the styrenic resin (A) is subjected to molecular design and polymerization design as described above as compared with ordinary polystyrene having the same molecular weight, so that the set temperature of the extruder and molding machine is 10 ° C. to It can be lowered by about 20 ° C. The fact that the set temperature can be lowered in this way has the effect of reducing the heat generated by friction between the resin, the extruder and the molding machine. The heat deterioration of the flame retardant to be kneaded and the styrene type due to the decomposition of the flame retardant It is possible to suppress a decrease in the molecular weight of the resin and a decrease in the strength of the molded product. Furthermore, even when material recycling is performed, it is possible to increase the blending ratio of the recycled product.

  Hereinafter, the present invention will be described more specifically with reference to examples. The present invention should not be limited to the scope of these examples. Hereinafter, “parts” and “%” are based on weight unless otherwise specified.

The measurement method used will be described.
[GPC measurement conditions for hyperbranched macromonomer]
GPC measurement of a multi-branched macromonomer was performed using high performance liquid chromatography (HLC-8220GPC manufactured by Tosoh Corporation), RI detector, TSK gel G6000H × 1 + G5000H × 1 + G4000H × 1 + G3000H × 1 + TSK guard column H × 1, solvent THF, flow rate 1 It was carried out under the conditions of 0.0 ml / min and a temperature of 40 ° C.

[GPC-MALLS measurement]
GPC-MALLS measurement of the styrene resin was performed under the conditions of Shodex HPLC, detector Wyatt Technology DAWN EOS, Shodex RI-101, column Shodex KF-806L × 2, solvent THF, and flow rate of 1.0 ml / min. GPC-MALLS measurement was analyzed using Wyatt's analysis software ASTRA, and the weight average molecular weight of the styrene-based resin (A) was determined. In addition, the molecular weight of the resin determined from GPC-MALLS was plotted on the horizontal axis and inertia. The slope in the region of molecular weight 250,000 to 10 million in the log-log graph with the radius as the vertical axis was determined.

[NMR measurement method (multi-branched macromonomer)]
The double bond property of the multi-branched macromonomer was determined from the double bond peak by dissolving in deuterated chloroform by nuclear magnetic resonance spectroscopy ( ¹ H-NMR).

[NMR measurement method (amount of flame retardant in resin)]
Regarding the amount of flame retardant in the resin, 15 mg of the resin was dissolved in a mixed solvent of deuterated chloroform: deuterated DMSO = 2: 1 (weight ratio) by nuclear magnetic resonance spectroscopy ( ¹ H-NMR), and polystyrene (6. 0 to 7.5 ppm) and a flame retardant (hexabromocyclododecane, hereinafter referred to as HBCD, 4.6 to 5.0 ppm). From these values, the residual ratio of flame retardant (%) = the amount of flame retardant after heat history / the amount of added flame retardant was obtained.

  The flame retardancy and resin degradation of Examples and Comparative Examples other than HBCD were examined based on the molecular weight, Charpy impact strength, and UL94 V1 standard of the UL combustion test method. The flame retardancy was evaluated as ◯ for those that met the V1 standard, and x for those that did not.

[Melt Mass Flow Rate Measurement Method]
The measurement was performed according to JIS K7210. The measurement conditions are a temperature of 200 ° C. and a load of 49N.

[Molding method]
A flame retardant is dry-blended with a styrene resin in advance, and melt-mixed (residence time 5 minutes, 200 ° C. and 190 ° C.) using a twin-screw extruder (PCM-30 manufactured by Ikegai Seisakusho). And re-pelletized. Using the re-pelleted sample, a molded article for evaluation was obtained with an injection molding machine (melting temperature: 210 ° C. and 200 ° C., residence time: 4 minutes). About the external appearance of the obtained molded article for evaluation, it judged visually. (Good appearance ○, slightly bad Δ, bad x)

[Mechanical strength (Charpy impact test)]
It measured according to JIS K7111: 96.

Reference Example 1 Synthesis of Multibranched Macromonomer (Mm-1) <Synthesis of Multibranched Macromonomer Having Methacryloyl Group and Acetyl Group>
In a reaction vessel equipped with a 7% oxygen inlet tube, a thermometer, a Dean-Stark decanter equipped with a condenser, and a stirrer, 10 g of “Borton H20”, 1.25 g of dibutyltin oxide, 100 g of methyl methacrylate having an isopropenyl group, and hydroquinone 0.05 g was added, and the mixture was heated with stirring while blowing 7% oxygen at a rate of 3 ml / min. The amount of heating is adjusted so that the amount of distillate in the decanter is 15 to 20 g per hour, the distillate in the decanter is taken out every hour, and the corresponding amount of methyl methacrylate is added for 4 hours. Reacted. After completion of the reaction, methyl methacrylate was distilled off under reduced pressure, and 10 g of acetic anhydride and 2 g of sulfamic acid were added to cap the remaining hydroxy groups, followed by stirring at room temperature for 10 hours. After removing sulfamic acid by filtration and distilling off acetic anhydride and acetic acid under reduced pressure, the residue was dissolved in 70 g of ethyl acetate and washed 4 times with 20 g of 5% aqueous sodium hydroxide to remove hydroquinone. Further, it was washed twice with 20 g of a 7% aqueous sulfuric acid solution and twice with 20 g of water. To the obtained organic layer, 0.0045 g of methoquinone was added, and the solvent was distilled off while introducing 7% oxygen under reduced pressure to obtain 11 g of a hyperbranched macromonomer (Mm-1) having an isopropenyl group and an acetyl group. It was. The resulting multi-branched macromonomer (Mm-1) has a weight average molecular weight of 3,000, a number average molecular weight of 2,100, and a double bond introduction amount of 2.00 mmol / g, an isopropenyl group and an acetyl group. The introduction rates were 55% and 36%, respectively.

Reference Example 2 Synthesis of Multibranched Macromonomer (Mm-2) <Synthesis of Multibranched Macromonomer Having Methacryloyl Group and Acetyl Group>
In a reaction vessel equipped with a 7% oxygen inlet tube, a thermometer, a Dean-Stark decanter equipped with a condenser, and a stirrer, 10 g of “Borton H30”, 1.75 g of dibutyltin oxide, 150 g of methyl methacrylate having an isopropenyl group, and hydroquinone 0.075 g was added, and the mixture was heated with stirring while blowing 7% oxygen at a rate of 3 ml / min. Adjust the amount of heating so that the amount of distillate in the decanter is 15 to 20 g per hour, take out the distillate in the decanter every hour, and add the corresponding amount of methyl methacrylate for 8 hours. Reacted. After completion of the reaction, methyl methacrylate was distilled off under reduced pressure, and 15 g of acetic anhydride and 3 g of sulfamic acid were added to cap the remaining hydroxy groups, followed by stirring at room temperature for 10 hours. After removing sulfamic acid by filtration and distilling off acetic anhydride and acetic acid under reduced pressure, the residue was dissolved in 100 g of ethyl acetate and washed 4 times with 20 g of 5% aqueous sodium hydroxide to remove hydroquinone. Further, it was washed twice with 20 g of a 7% aqueous sulfuric acid solution and twice with 20 g of water. To the obtained organic layer, 0.007 g of methoquinone was added, and the solvent was distilled off under introduction of 7% oxygen under reduced pressure to obtain 11 g of a hyperbranched macromonomer (Mm-2) having isopropenyl group and acetyl group. It was. The resulting multi-branched macromonomer (Mm-2) has a weight average molecular weight of 5,200, a number average molecular weight of 3,600, and a double bond introduction amount of 3.00 mmol / g, an isopropenyl group and an acetyl group. The introduction rates were 53% and 41%, respectively.

(Reference Example 3) Synthesis of hyperbranched macromonomer (Mm-3) <Synthesis of hyperbranched macromonomer having a methacryloyl group and an acetyl group>
In a reaction vessel equipped with a 7% oxygen introduction tube, a thermometer, a Dean-Stark decanter equipped with a condenser, and a stirrer, 10 g of “Borton H40”, 2.5 g of dibutyltin oxide, 200 g of methyl methacrylate having an isopropenyl group, and hydroquinone 0.1 g was added, and the mixture was heated with stirring while blowing 7% oxygen at a rate of 3 ml / min. The heating amount is adjusted so that the amount of distillate in the decanter is 15 to 20 g per hour, the distillate in the decanter is taken out every hour, and the corresponding amount of methyl methacrylate is added for 10 hours. Reacted. After completion of the reaction, methyl methacrylate was distilled off under reduced pressure, and 20 g of acetic anhydride and 4 g of sulfamic acid were added to cap the remaining hydroxy groups, followed by stirring at room temperature for 10 hours. After removing sulfamic acid by filtration and distilling off acetic anhydride and acetic acid under reduced pressure, the residue was dissolved in 70 g of ethyl acetate and washed 4 times with 20 g of 5% aqueous sodium hydroxide to remove hydroquinone. Further, it was washed twice with 20 g of a 7% aqueous sulfuric acid solution and twice with 20 g of water. To the obtained organic layer, 0.0045 g of methoquinone was added, and the solvent was distilled off while introducing 7% oxygen under reduced pressure to obtain 11 g of a hyperbranched macromonomer (Mm-3) having an isopropenyl group and an acetyl group. It was. The resulting multi-branched macromonomer (Mm-3) has a weight average molecular weight of 7,900, a number average molecular weight of 4,200, a double bond introduction amount of 2.90 mmol / g, an isopropenyl group and an acetyl group. The introduction rates were 49% and 48%, respectively.

Example 1
A mixed solution consisting of 90 parts of styrene monomer, 500 ppm of the hyperbranched macromonomer (Mm-1) obtained in Reference Example 1 with respect to the styrene monomer, and 10 parts of toluene was prepared, and further, the styrene monomer as an organic peroxide. 300 ppm of t-butylperoxybenzoate was added to the mixture, and bulk polymerization was continuously carried out under the following conditions using the apparatus shown in FIG.

Supply amount of mixed solution: 9 L / hr
Reaction temperature of the stirring reactor (2): 132 ° C.
Circulating polymerization line (I) reaction temperature: 150 ° C
Reaction temperature of non-circulation polymerization line (II): 150-170 ° C
Reflux ratio: R = F1 / F2 = 6
However, F1 shows the flow volume of the mixed solution which recirculates in the circulation polymerization line, and F2 shows the flow volume of the mixed solution which flows out to a non-circulation polymerization line.

  The mixed solution obtained by polymerization was heated to 220 ° C. with a heat exchanger, and after removing volatile components under a reduced pressure of 50 mmHg, pelletized to obtain a styrene resin (A-1).

  To 100 parts of the resulting styrene resin (A-1), 3 parts of hexabromocyclododecane (HBCD) is added and dry blended, and then melt-mixed at 200 ° C. using a twin screw extruder, followed by water cooling and strand cutting. And re-pelletized. Using the re-pelleted sample, a molded article for evaluation was obtained with an injection molding machine (molding temperature 190 ° C.).

  A log-log graph of the molecular weight and the radius of inertia obtained from GPC-MALLS of the obtained styrene-based resin (A-1) is shown in FIG.

Example 2
An evaluation molded product was obtained in the same manner except that the melt mixing temperature of Example 1 was 210 ° C. and the injection molding temperature was 200 ° C.

Example 3
A styrenic resin (A-2) was prepared in the same manner as in Example 1 except that the hyperbranched macromonomer (Mm-2) was used instead of the hyperbranched macromonomer (Mm-1) in Example 1. Obtained. After adding 3 parts of HBCD to 100 parts of the obtained styrene-based resin (A-2), the mixture was melt-mixed at 200 ° C. using a twin screw extruder, water-cooled, strand-cut and re-pelleted. Using the re-pelleted sample, a molded article for evaluation was obtained with an injection molding machine (molding temperature 190 ° C.).

Example 4
An evaluation molded product was obtained in the same manner except that the melt mixing temperature of Example 3 was 210 ° C. and the injection molding temperature was 200 ° C.

Example 5
A styrenic resin (A-3) was prepared in the same manner as in Example 1 except that the hyperbranched macromonomer (Mm-3) was used instead of the hyperbranched macromonomer (Mm-1) in Example 1. Obtained. After adding 3 parts of HBCD and dry blending to 100 parts of the resulting styrene-based resin (A-3), the mixture was melt-mixed at 200 ° C. using a twin screw extruder, water-cooled, strand cut, and repelletized. Using the re-pelleted sample, a molded article for evaluation was obtained with an injection molding machine (molding temperature 190 ° C.).

Example 6
An evaluation molded product was obtained in the same manner except that the melt mixing temperature of Example 5 was 210 ° C. and the injection molding temperature was 200 ° C.

Example 7
Styrenic resin (A-4) was obtained in the same manner as in Example 1 except that the hyperbranched macromonomer (Mm-1) in Example 1 was changed to 300 ppm. After adding 3 parts of HBCD to 100 parts of the resulting styrene resin (A-4) and dry blending, the mixture was melt-mixed at 200 ° C. using a twin screw extruder, water-cooled, strand cut, and repelletized. Using the re-pelleted sample, a molded article for evaluation was obtained with an injection molding machine (molding temperature 190 ° C.).

Example 8
An evaluation molded product was obtained in the same manner except that the melt mixing temperature was changed to 210 ° C and the injection molding temperature was changed to 200 ° C under the conditions of Example 7.

Example 9
A mixed solution consisting of 90 parts of styrene monomer, 1800 ppm of the hyperbranched macromonomer (Mm-1) obtained in Reference Example 1 and 10 parts of toluene with respect to the styrene monomer, and further, styrene monomer as an organic peroxide 300 ppm of t-butylperoxybenzoate was added to the mixture, and bulk polymerization was continuously carried out under the following conditions using the apparatus shown in FIG.

Supply amount of mixed solution: 9 L / hr
Reaction temperature of the stirring reactor (2): 132 ° C.
Circulating polymerization line (I) reaction temperature: 150 ° C
Reaction temperature of non-circulation polymerization line (II): 160 to 170 ° C
Reflux ratio: R = F1 / F2 = 6
However, F1 shows the flow volume of the mixed solution which recirculates in the circulation polymerization line, and F2 shows the flow volume of the mixed solution which flows out to a non-circulation polymerization line.

  The mixed solution obtained by polymerization was heated to 220 ° C. with a heat exchanger to remove volatile components under a reduced pressure of 50 mmHg, and then pelletized to obtain a styrene resin (A-5).

  After adding 3 parts of HBCD and dry blending to 100 parts of the resulting styrene-based resin (A-5), the mixture was melt-mixed at 200 ° C. using a twin-screw extruder, water-cooled, strand cut, and repelletized. Using the re-pelleted sample, a molded article for evaluation was obtained with an injection molding machine (molding temperature 190 ° C.).

Example 10
An evaluation molded product was obtained in the same manner except that the melt mixing temperature was changed to 210 ° C and the injection molding temperature was changed to 200 ° C under the conditions of Example 9.

Example 11
An evaluation molded product was obtained in the same manner except that the HBCD of Example 1 was changed to 8 parts.

Example 12
An evaluation molded product was obtained in the same manner except that the melt mixing temperature was changed to 210 ° C and the injection molding temperature was changed to 200 ° C under the conditions of Example 11.

Example 13
An evaluation molded product was obtained in the same manner except that the HBCD of Example 1 was changed to 2 parts.

Example 14
After adding 3% tetrabromobisphenol A to the styrenic resin (A-3) obtained in Example 5 and dry blending, the mixture is melt-mixed at 200 ° C. using a twin screw extruder, water-cooled, and strand-cut. And re-pelletized. Using the re-pelleted sample, a molded product (first time) was obtained with an injection molding machine (molding temperature 190 ° C.). Further, the molded product was pulverized, and a molded product (second time) was obtained with an injection molding machine (molding temperature 190 ° C.).

Example 15
An evaluation molded product was obtained in the same manner except that the melt mixing temperature was changed to 210 ° C and the injection molding temperature was changed to 200 ° C under the conditions of Example 14.

Example 16
In accordance with the ratio of 100 parts of (A-3) to 20 parts (pulverized product) of the molded product obtained in Example 5 and 80 parts of styrene-based resin (A-3), 2.4 parts of HBCD are obtained. It melt-mixed at 200 degreeC using the axial extruder, water-cooled, strand-cut and re-pelletized. Using the re-pelleted sample, a molded article for evaluation was obtained with an injection molding machine (molding temperature 190 ° C.).

Comparative Example 1
Styrenic resin (A′-1) was obtained in the same manner as in Example 1 except that the hyperbranched macromonomer (Mm-1) in Example 1 was changed to 100 ppm. After adding 3 parts of HBCD to 100 parts of the resulting styrene resin (A′-1) and dry blending, the mixture was melt-mixed at 200 ° C. using a twin-screw extruder, water-cooled, strand-cut and re-pelletized. Using the re-pelleted sample, a molded article for evaluation was obtained with an injection molding machine (molding temperature 190 ° C.).

Comparative Example 2
An evaluation molded product was obtained in the same manner except that the melt mixing temperature was changed to 210 ° C and the injection molding temperature was changed to 200 ° C under the conditions of Comparative Example 1.

Comparative Example 3
A mixed solution consisting of 90 parts of styrene monomer, 500 ppm of the hyperbranched macromonomer (Mm-1) obtained in Reference Example 1 with respect to the styrene monomer, and 10 parts of toluene was prepared, and further, the styrene monomer as an organic peroxide. 300 ppm of t-butylperoxybenzoate was added to the mixture, and bulk polymerization was continuously carried out under the following conditions using the apparatus shown in FIG.

Supply amount of mixed solution: 9 L / hr
Reaction temperature of the stirring reactor (2): 132 ° C.
Circulating polymerization line (I) reaction temperature: 138 ° C
Reaction temperature of non-circulation polymerization line (II): 150-170 ° C
Reflux ratio: R = F1 / F2 = 6
However, F1 shows the flow volume of the mixed solution which recirculates in the circulation polymerization line, and F2 shows the flow volume of the mixed solution which flows out to a non-circulation polymerization line.

  The mixed solution obtained by polymerization was heated to 220 ° C. with a heat exchanger, and after removing volatile components under reduced pressure of 50 mmHg, pelletized to obtain a styrene resin (A′-2).

  To 100 parts of the resulting styrene resin (A′-2), 3 parts of hexabromocyclododecane (HBCD) is added and dry blended, and then melt-mixed at 200 ° C. using a twin-screw extruder, water-cooled, strands Cut and re-pelletized. Using the re-pelleted sample, a molded article for evaluation was obtained with an injection molding machine (molding temperature 190 ° C.).

Comparative Example 4
An evaluation molded product was obtained in the same manner except that the melt mixing temperature was changed to 210 ° C and the injection molding temperature was changed to 200 ° C under the conditions of Comparative Example 3.

Comparative Example 5
A mixed solution consisting of 90 parts of styrene monomer and 10 parts of toluene was further prepared. Further, 200 ppm of t-butylperoxybenzoate was added as an organic peroxide to the styrene monomer, and it was continuously used under the following conditions using the apparatus shown in FIG. Bulk polymerization was performed.

Supply amount of mixed solution: 9 L / hr
Reaction temperature of the stirring reactor (2): 135 ° C
Circulating polymerization line (I) reaction temperature: 140 ° C
Reaction temperature of non-circulation polymerization line (II): 150-170 ° C
Reflux ratio: R = F1 / F2 = 6
However, F1 shows the flow volume of the mixed solution which recirculates in the circulation polymerization line, and F2 shows the flow volume of the mixed solution which flows out to a non-circulation polymerization line.

  The mixed solution obtained by polymerization was heated to 220 ° C. with a heat exchanger to remove volatile components under a reduced pressure of 50 mmHg, and then pelletized to obtain a styrene resin (A′-3).

  After adding 3 parts of HBCD and dry blending to 100 parts of the resulting styrene-based resin (A′-3), the mixture was melt-mixed at 200 ° C. using a twin-screw extruder, water-cooled, strand-cut and re-pelleted. Using the re-pelleted sample, a molded article for evaluation was obtained with an injection molding machine (molding temperature 190 ° C.).

Comparative Example 6
An evaluation molded product was obtained in the same manner except that the melt mixing temperature was changed to 210 ° C and the injection molding temperature was changed to 200 ° C under the conditions of Comparative Example 5.

Comparative Example 7
A mixed solution consisting of 90 parts of styrene monomer and 10 parts of toluene was further prepared. Further, 100 ppm of t-butylperoxybenzoate was added as an organic peroxide to the styrene monomer, and continuous using the apparatus shown in FIG. 1 under the following conditions. Bulk polymerization was performed.

Supply amount of mixed solution: 9 L / hr
Reaction temperature of the stirring reactor (2): 140 ° C
Circulating polymerization line (I) reaction temperature: 145 ° C
Reaction temperature of non-circulation polymerization line (II): 150-170 ° C
Reflux ratio: R = F1 / F2 = 6
However, F1 shows the flow volume of the mixed solution which recirculates in the circulation polymerization line, and F2 shows the flow volume of the mixed solution which flows out to a non-circulation polymerization line.

  The mixed solution obtained by polymerization was heated to 220 ° C. with a heat exchanger to remove volatile components under a reduced pressure of 50 mmHg, and then pelletized to obtain a styrene resin (A′-4).

  After adding 3 parts of HBCD and dry blending to 100 parts of the resulting styrene resin (A′-4), it was melt-mixed at 200 ° C. using a twin-screw extruder, water-cooled, strand-cut and re-pelletized. Using the re-pelleted sample, a molded article for evaluation was obtained with an injection molding machine (molding temperature 190 ° C.).

Comparative Example 8
An evaluation molded product was obtained in the same manner except that the melt mixing temperature was changed to 210 ° C and the injection molding temperature was changed to 200 ° C under the conditions of Comparative Example 7.

Comparative Example 9
A mixed solution consisting of 90 parts of styrene monomer and 10 parts of toluene was further prepared. Further, 200 ppm of t-butylperoxybenzoate was added as an organic peroxide to the styrene monomer, and it was continuously used under the following conditions using the apparatus shown in FIG. Bulk polymerization was performed.

Supply amount of mixed solution: 9 L / hr
Reaction temperature of the stirring reactor (2): 130 ° C
Circulating polymerization line (I) reaction temperature: 135 ° C
Reaction temperature of non-circulation polymerization line (II): 140-160 ° C
Reflux ratio: R = F1 / F2 = 6
However, F1 shows the flow volume of the mixed solution which recirculates in the circulation polymerization line, and F2 shows the flow volume of the mixed solution which flows out to a non-circulation polymerization line.

  The mixed solution obtained by polymerization was heated to 220 ° C. with a heat exchanger to remove volatile components under a reduced pressure of 50 mmHg, and then pelletized to obtain a styrene resin (A′-5).

  After adding 3 parts of HBCD and dry blending to 100 parts of the resulting styrene resin (A′-5), the mixture was melt-mixed at 200 ° C. using a twin-screw extruder, water-cooled, strand-cut and re-pelletized. Using the re-pelleted sample, a molded article for evaluation was obtained with an injection molding machine (molding temperature 190 ° C.).

Comparative Example 10
An evaluation molded product was obtained in the same manner except that the melt mixing temperature was changed to 210 ° C and the injection molding temperature was changed to 200 ° C under the conditions of Comparative Example 7.

Comparative Example 11
A mixed solution consisting of 90 parts of styrene monomer and 10 parts of toluene was prepared and polymerized continuously using the apparatus shown in FIG. 1 under the following conditions.

Supply amount of mixed solution: 9 L / hr
Reaction temperature of the stirring reactor (2): 140 ° C
Circulating polymerization line (I) reaction temperature: 145 ° C
Reaction temperature of non-circulation polymerization line (II): 150-170 ° C
Reflux ratio: R = F1 / F2 = 6
However, F1 shows the flow volume of the mixed solution which recirculates in the circulation polymerization line, and F2 shows the flow volume of the mixed solution which flows out to a non-circulation polymerization line.

  The mixed solution obtained by polymerization was heated to 220 ° C. with a heat exchanger to remove volatile components under a reduced pressure of 50 mmHg, and then pelletized to obtain a styrene resin (A′-6).

  After adding 3 parts of HBCD and dry blending to 100 parts of the resulting styrene resin (A′-6), it was melt-mixed at 200 ° C. using a twin-screw extruder, water-cooled, strand-cut and re-pelleted. Using the re-pelleted sample, a molded article for evaluation was obtained with an injection molding machine (molding temperature 190 ° C.).

Comparative Example 12
An evaluation molded product was obtained in the same manner except that the melt mixing temperature was changed to 210 ° C and the injection molding temperature was changed to 200 ° C under the conditions of Comparative Example 7.

Comparative Example 13
An evaluation molded product was obtained in the same manner except that the HBCD of Comparative Example 5 was changed to 8 parts.

Comparative Example 14
An evaluation molded product was obtained in the same manner except that the melt mixing temperature was changed to 210 ° C and the injection molding temperature was changed to 200 ° C under the conditions of Comparative Example 13.

Comparative Example 15
3% tetrabromobisphenol A (TBBPA) is added to styrene resin (A'-5), dry blended, melt-mixed at 200 ° C using a twin screw extruder, water cooled, strand cut and repelletized. did. Using the re-pelleted sample, a molded product (first time) was obtained with an injection molding machine (molding temperature 190 ° C.). Further, the molded product was pulverized again, and a molded product (second time) was obtained with an injection molding machine (molding temperature 190 ° C.).

Comparative Example 16
An evaluation molded product was obtained in the same manner except that the melt mixing temperature was changed to 210 ° C and the injection molding temperature was changed to 200 ° C under the conditions of Comparative Example 15.

Comparative Example 17
In accordance with the ratio to 100 parts of (A'-3), 20 parts (pulverized product) of the molded product obtained in Comparative Example 5 and 80 parts of styrene-based resin (A'-3), 2.4 parts of HBCD, and again The mixture was melt-mixed at 200 ° C. using a twin-screw extruder, water-cooled, strand-cut and re-pelletized. Using the re-pelleted sample, a molded article for evaluation was obtained with an injection molding machine (molding temperature 190 ° C.).

Comparative Example 18
In accordance with the ratio of 20 parts (pulverized product) of the molded product obtained in Comparative Example 9 and 80 parts of styrene-based resin (A′-5) to 100 parts of (A′-5), 2.4 parts of HBCD were obtained. The mixture was melt-mixed at 200 ° C. using a twin-screw extruder, water-cooled, strand-cut and re-pelletized. Using the re-pelleted sample, a molded article for evaluation was obtained with an injection molding machine (molding temperature 190 ° C.).

Comparative Example 19
After adding 50 parts of linear polystyrene (weight average molecular weight: Mw 180,000), 50 parts of linear polystyrene (weight average molecular weight: Mw 220,000) and 3 parts of HBCD and dry blending, 200 ° C. using a twin screw extruder. The mixture was melt-mixed with water, cooled with water, cut into strands, and re-pelletized. Using the re-pelleted sample, a molded product was obtained with an injection molding machine (molding temperature 190 ° C.). As this molded product, 20 parts, linear polystyrene (weight average molecular weight: Mw 180,000) 40 parts, linear polystyrene (weight average molecular weight: Mw 220,000) 40 parts, and HBCD 2.4 parts, again the twin screw extruder The mixture was melt-mixed at 200 ° C., cooled with water, cut into strands, and re-pelletized. Using the re-pelleted sample, a molded article for evaluation was obtained with an injection molding machine (molding temperature 190 ° C.).

Footnotes in Tables 2-5:
Molecular weight retention (%) = Mw of molded product / Mw of styrene resin

  From Tables 2 to 5, it is clear that the styrenic resin composition of the present invention and a molded product comprising the same retain flame retardancy, and can suppress strength and molecular weight reduction and material recycling. It is also clear that low-temperature extrusion molding that does not interfere with sufficient physical properties and molding processing is possible, and because the retention rate of the flame retardant is high (decrease in flame retardant degradation), the amount of flame retardant added can be reduced. .

It is process drawing which shows one example of the continuous polymerization line incorporating the tubular reactor which has a static mixing element. It is the logarithm graph of the molecular weight of a styrene resin mixture (A-1) calculated | required from GPC-MALLS, and an inertia radius.

Explanation of symbols

(1): Plunger pump (2): Stirred reactor (3), (7): Gear pumps (4) to (6), (8) to (10): Tubular reactor having a static mixing element

Claims (4)

A multi-branched macromonomer (a1) comprising a styrene-based resin (A) and a flame retardant (B), wherein the styrene-based resin (A) has a double bond at a branched end. A styrene resin composition comprising a resin obtained by copolymerizing a styrene monomer (a2) with a melt mass flow rate (MFR) at 200 ° C. of 4.0 to 10.0 g / 10 min. object. In the logarithmic graph in which the styrene-based resin (A) has a molecular weight determined by the GPC-MALLS method on the horizontal axis and the inertial radius on the vertical axis, the slope in the region of the molecular weight of 250,000 to 10 million is 0.35 to 0 The styrenic resin composition according to claim 1, which is .45. The styrene resin composition according to claim 1 or 2, wherein the flame retardant (B) is a halogen flame retardant (b). The styrene resin composition according to claim 3, wherein the halogen flame retardant (b) is a bromine flame retardant.

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