TWI240740B - Styrenic resin for injection-molding - Google Patents

Abstract

The invention provides a styrenic resin for injection-molding. The ratio of Z average molecular weight (Mz) to the weight average molecular weight (Mw) of the resin is not less than 2.0. And more than 53 weight % of resins based on total resins have molecular weights of 50,000 to 300,000. The sum of the dimer and the trimer derived from the styrenic monomers is less than 8,000 ppm. In addition, the amount of the styrenic monomers in the resin is less than 1,000 ppm. The resin has a better fluidity and high strength of physical property equilibrium since its special distribution range of molecular weight, and less oligomers and residue monomers. Meanwhile, the resin has not the disadvantage of polluting the mold while molding, and is suitable for the injection-molding of thin articles at high temperature and operating velocity.

Description

Printed in the Ministry of Economic Affairs-y Bayong Consumer Cooperative 1240740 A-7 ------- V. Description of the Invention (1) ------- This invention relates to a polystyrene resin composition, especially a : Use a specific molecular weight distribution range and control the amount of oligomer and residual monomers to improve the resin's fluidity and high-strength physical properties' balance, making the resin suitable for high temperature and high speed thin parts. Polystyrene resin is a kind of non-crystalline molecular structure. It has ten years of processing and molding, and its price is comparable to other plastic materials. It is competitive and practical, so it is widely used in various industries. Packaging materials, food containers, toys, computer peripherals and other items; nevertheless, the higher the average molecular weight of polystyrene resins, the higher the tensile strength, but the lower the fluidity of the relative resin, However, if you want to improve the fluidity of the resin, you must add a large amount of wax oil or use a low average molecular weight polybenzyl. This will greatly reduce the tensile strength of the resin. When the resin is molded at high temperature and high speed It is also easy to form oil deposits on the mold surface, causing defects on the printed surface of the forming part, and the surface of the mold will rust. It is necessary to increase the frequency of maintenance and wiping, which affects the production efficiency. Obviously, the general polystyrene resin composition cannot be simultaneously Consider both fluidity and rigidity. In addition, with the advancement of technology, in addition to the need to reduce costs and improve competitiveness, it is a common trend for manufacturers to reduce the thickness of products and shorten the molding cycle. Based on the foregoing examinations 1, how to improve fluidity and strength is The subject of much improvement in the manufacture of polyethylene resin. In view of the fact that the polystyrene resin used in injection molding, the inventors of the present case: the aforementioned defects occurred. After intensive research, it was found that the molecular weight distribution range of the resin was adjusted and the stupid vinyl monomer derived in the resin was controlled. -______ Page 3 This paper rule applies the Chinese National Standard (CNS) Λ4 specification (210X29 * 7) while it is printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs 1240740 Λ7 ---------- ___ V. Description of the invention (3) Styrene, second butyl styrene, and styrene with halogen substituents such as dichlorostyrene and ethyl bromide, among which styrene and ^ -methylstyrene are Preferably, it can be used alone or in combination of two or more. The copolymerizable monomer of the present invention refers to the specificity of other monofunctional vinyl monomers or polyfunctional vinyl monomers that can be copolymerized with styrenic monomers, and the specific properties of monoethylenic monomers. Examples include: methyl methacrylate, methacrylic acid, maleic anhydride, acrylonitrile, and the like; and the polyfunctional vinyl monomer that can be used in the resin of the present invention is not particularly limited, as long as it can be performed What is necessary is a radically polymerized polyfunctional ethynyl compound. Specific examples of polyfunctional vinyl monomers: 1) di vinyl benzene, 1,2,4-trivinyl benzene, 1,3,5 -Divinyls such as trivinylbenzene (i, 3,5-tri vinyl benzene). 2) ethylene glycol dimethacrylate, di ethylene glycol dimethacrylate, tri ethylene glycol dimethacrylate, triethylene glycol dimethacrylate dimethacrylate), polyethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 1,3-propylene glycol dimethacrylate, 1,4-butanediol dipropylene 1,4-butylene glycol dimethacrylate, 1,6-hexanene glycol dimethacrylate, neopentyl dimethacrylate, neo pentyl glycol dimethacrylate '(referred to as PGDMA), dipropylene glycol dipropionic acid disulfide (dipropylene glycol page 5) This paper size applies the Chinese National Standard (CNS) Λ4 specification (2ί〇Χ 297 公 楚) Approval ------ T —1T ------ ^ (Please read the notes on the back before filling out this page) 1240740 Λ7 V. Description of the Invention (4) dimethacrylate), polypropylene glycol dimethacrylate, 2, 2-bis- (4-methylpropanoic acid oxydiethyl Phenyl) propan-burning [2,2_bis- (4-methacryloxy diethoxy phenyl) propane] methanesulfonic acid and the like vinegar dipropyl women. 3) Trimethylol propane trimethacrylate, triethylol ethane trimethacrylate and other trimethylol methyl esters. Printed by the Consumer Cooperatives of the Central Bureau of Standards of the Ministry of Economic Affairs (please read the notes on the back before filling out this page) 4) ethylene glycol diacrylate, diethylene glycol diacrylate glycol diacrylate), tri ethylene glycol diacrylate, polyethylene glycol diacrylate, 1,3-di-propylene glycol dipropionic acid (l, 3-di -propylene glycol diacrylate), 1,4-di-butylene glycol diacrylate, 1,6-di-butylene glycol diacrylate, 1,6-hexylene glycol diacrylate glycol diacrylate), neopentyl glycol diacrylate (PGDA), di propylene glycol diacrylate, polypropylene glycol diacrylate, 2, 2-bis (4-acryloxyphenyl) propane [2,2-bis (4-acryloxy propoxy phenyl) propane], 2,2-bis (4-acryloxydiethoxyphenyl) Propylene [2,2-bis (4-acryloxy di ethoxy phenyl) propane] and other diacrylates . 5) Triacrylates such as trimethylol propane triacrylate and triethylol ethane triacrylate. __The fi hundredth paper standard applies to the Chinese National Standard (CNS) Λ4 specification (210X 297). Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs 1240740 A7 B · ^ 5. Description of the invention (5) 6) Sijingjia Tetramethylol methane tetraacrylate and other tetramethylol g derivatives. Of these, methyl neopentyl alcohol diacrylate and neopentyl alcohol diacrylate are preferred. The above-mentioned polyfunctional vinyl monomers may be used singly or in combination of two or more kinds. Generally speaking, the amount used is 0 to 1.0% by weight of the overall resin, preferably 0.005 to 0.6% by weight, more It is preferably 〇1 ～ 0.4% by weight: When the amount of the polyfunctional vinyl monomer exceeds 1.0% by weight, the polymer I is liable to gel, which may result in a reaction tank and a devolatilizer. There is a phenomenon of blocking materials, even the occurrence of black spots; and by using an appropriate ratio between the styrene-based monomer and the polyfunctional vinyl monomer for the polymerization reaction, in addition to obtaining a polystyrene polymer with a divergent structure In addition, it also helps the present invention to achieve the purpose of proper molecular weight distribution. The starter that can be used in the production of the polystyrene resin of the present invention may be: a monofunctional starter or a polyfunctional starter, wherein the specific monofunctional starter is, for example, diphenyl peroxide Benzoyl peroxide, dicumyl peroxide, dibenzoyl peroxide, dibenzoyl peroxide, di benzoyl superoxide, tertiary butyl peroxide T-butyl hydroperoxide, cumene hydroperoxide, t-butyl-benzoate, di-2-peroxyhexyl dicarbonate (di- 2-ethylhexyl peroxy dicarbonate), tert-butyl peroxy isopropyl carbonate (BPIC), cycolhexanoe peroxide, 2,2'-azo-bis -Isobutyronitrile (2,2'-azo-bis-isobutyronitrile), 1,1 '-Azobis-1-cyclohexane compound Wei Nitrile _ page 7 _ This paper size applies to the Chinese National Standard (CNS) A4 specifications (210X297)

Approved clothing 1T line (please read the precautions on the back before filling in this hundred C 1240740 Λ7 Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs 5. Description of the invention (6) (1, Γ-azo-bis-l-cyclohexane carbonitrile) , 2,2'-azo-bis-2-methyl butyronitrile (2,2'-azo-bis-2-methyl butyronitrile), etc. Specific examples of the polyfunctional starter usable in the present invention are: 1,1-di-t-butyl peroxy cyclohexane (TX-22 for short), 1,1-di-t-butyl peroxy cyclohexane, 5-trimethylcyclohexane (l, l-di-t-butylperoxy-3,3,5-trimethyl cyclohexane, TX-29A for short), 2,5-dimethyl-2,5_bis- (2 -Ethylperoxyhexyl) hexane [2,5-dimethyl-2,5-bis- (2-ethylhexanoxy peroxy) hexane], 4- (peroxy third butylcarbonyl) -3-hexyl-6- [7- (Third-butyl peroxy) heptyl] cyclohexyl {4- (t-butyl peroxy carbonyl) -3-hexyl-6- [7- (t-butyl peroxy carbonyl) heptyl] cyclohexane}, Di-t-butyl-diperoxyazelate, 2,5-dimethyl-2,5-bis (benzidine peroxide) -hexane [2,5- dimethyl-2, 5-bis- (benzoyl peroxy) hexane], di-t-butyl peroxy-hexahydro-terephthalate (BPHTP), 2,2-bis ( 4,4-di-peroxy third butyl) cyclohexylpropane [2,2-bis- (4,4-di-t-butyl peroxy) cyclohexanyl propane], etc .; the above-mentioned initiators can be used alone or in combination For the purposes of the present invention, the use of a polyfunctional starter will facilitate proper molecular weight distribution, with di-peroxy third butyl-hexahydro-terephthalate and 1,1-di-peroxy Oxy third butyl-3,3,5-trimethylcyclohexane is preferred; the amount of the initiator used in the present invention is 0 to 0.5 parts by weight relative to 100 parts by weight of the styrene-based monomer, preferably 0.001 ~ 0.2 parts by weight, more preferably 0.005 ~ 0.1 parts by weight; when the amount of initiator used exceeds 0.5 parts by weight, polymerization ___ page 8 _ This paper size applies to the Chinese national ^^ (CNS) A4 size (210X 297mmt) (Please read the precautions on the back before filling this page)

1240740 Printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs Λ * B 'V. Description of the invention (7) The molecular weight control of the substance is not easy, and the polymerization rate is difficult to control; The monomers are added together or in the middle of the reaction. The method of addition can be one-time addition or batch addition. The chain transfer agent that can be used in the production of the polystyrene resin of the present invention can be a monofunctional chain transfer agent. Or polyfunctional chain transfer agents, and the specific monofunctional chain transfer agents are: 1 1) Mercaptans: methyl mercaptan, n-butyl mercaptan, cyclohexyl mercaptan, n- Dodecyl mercaptan, stearyl mercaptan, t-dodecyl mercaptan (TDM for short), n-propyl mercaptan, n-octyl mercaptan , Third-octyl mercaptan, third-nonyl mercaptan, and the like. 2) Alkylamines: monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, monobutylamine, di-n-butylamine, triamine N-butylamine. Other examples: pentaphenylethane, α-methyl 'styrene dimer (a-methyl styrene dimer), terpinolene 〇 polyfunctional chain transfer agent is for example: tetra ( 3-M-based propionic acid) pentaerythritol tetrakis (3-mercapto propionate)], tetrakis (2-mercaptoacetic acid) isopentaerythritol [pentaerythritol tetrakis (2-mercapto ethanate)], tetrakis (4-M-butyric acid) ) Isopentaerythritol [pentaerythritol tetrakis (4-mercapto butanate)], tetrakis (5-weiyl valerate) isopentatriol [pentaerythritol tetrakis (5-mercapto pentanate)], tetrakis (6-meryl Paper size applies Chinese National Standard (CNS) A4 specification (210X 297 cm) --------- Approved clothing ------ 1T ------ line (Please read the precautions on the back first (Fill in this page again) 1240740 Α: Β / V. Description of the invention (8) Hexaman) isopentaerythritol [pentaerythritol tetrakis (6-mercapto hexanate)], tris- (2-weiyl acetic acid) tris (methyl) propane [Trimethylolpropane tris (2-mercapto ethanate)], [trimethylolpropane tris (3-mercapto ethanate)] te), TMPT for short, trimethylolpropane tris (4-mercapto butanate), tri- (5-mercaptobutanate) trimethylol [trimethylolpropane tris (5-mercapto pentanate)], trimethylol-propane tris (6-mercapto pentanate)], etc .. Polymerization of the polystyrene resin of the present invention In terms of a monofunctional chain transfer agent or a polyfunctional chain transfer agent, on the other hand, in order to obtain an appropriate molecular weight distribution, it is better to use a polyfunctional chain transfer agent. The use amount of the transfer agent is 0 to 0.5 parts by weight, preferably 0.01 to 0.4 parts by weight relative to 100 parts by weight of the polystyrene-based monomer. When the use amount of the chain transfer agent exceeds 0.5 parts by weight, The molecular weight of the resin during molding will decrease, which will cause the mechanical strength of the molded product to deteriorate. Printed by the Consumers' Cooperative of the Central Bureau of Standards, Ministry of Economic Affairs (please read the precautions on the back before filling this page) The types of solvents that can be used in the polymerization of the polystyrene resin of the present invention are: aromatic hydrocarbons, ketones, Esters, among which the best aromatic hydrocarbons are, for example, toluene, ethylbenzene, and xylene, while ketones are preferably methyl ethyl ketone, and esters are preferably ethyl acetate; in addition, the present invention can also be used Aliphatic hydrocarbons such as n-ethane, cyclohexane, and n-heptane are part of the solvent. The polystyrene resin of the present invention can be added with a polyfunctional vinyl monomer, a polyfunctional starter or a polyfunctional chain transfer agent as required during manufacture. Page 10 This paper applies Chinese national standards (CNS) A4 specification (X 297 mm) 1240740 Printed by the Consumers Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs A7 B7 Invention description (9), one or two or more of the above ingredients can be selected and used in combination, for example, multifunctional ethyl ethyl It can be used in combination with various kinds of monomers, such as a combination of a polyfunctional vinyl monomer and a polyfunctional initiator, or a combination of a polyfunctional initiator and a polyfunctional chain transfer agent. The purpose of the present invention is further achieved. The polystyrene resin of the present invention refers to a polymer obtained by polymerizing a styrene monomer as a main component. The polystyrene resin can be: impact-resistant polystyrene resin, styrene-α-methylstyrene resin, and styrene-fluorene. Methyl acrylate resin, polystyrene resin, etc .; In terms of transparency, a styrene resin containing no rubber component is preferred. In addition, the present invention can also add appropriate amounts of antioxidants and lubricants during the polymerization process to achieve better physical properties, where the antioxidants can improve the oxidative cracking; the antioxidants that can be used in the present invention are, for example: 2, 6-di-t-butyl-4-methyl phenol, tri nonyl phenyl phosphite, stearyl -3- (3,5--mono-second butyl-4- via basic group) propionic acid S [octadecy 1 -3- (3,5-di-1_butyl-4-hydroxy-phenyl) propionate ], Thio-diethylidene-bis (3,5 · di-tert-butyl-4-meryl-cold-phenylpropionic acid) [thio diethylene bis (3,5- di-t-tert-4- hydroxy hydrocinnamate), Tetrakis [3,5-Di-Third-Butyl-4-Ethyl- / 3-Phenylpropanoic Acid]] T ^ {Tetrakis [methylene (3,5-di-t-tert -4-hydroxy hydrocirnamate)] methane}, 2,4-bis [(thio) octyl vinegar] {2,4-bis [(octyl thio) phosphite]}, Dilauryl thiodipropionate thio di propionate), di stearyl thio di propionate, triethylene glycol-bis-3- (3-third butyl-4- Paper size applies to China National Standard (CNS) A4 (210X 297 mm) --------- Approved clothing ------ 1T ------ ^ (Please read the precautions on the back first (Fill in this page again) 1240740 Printed by A7 B1, Consumer Cooperatives, Central Bureau of Standards, Ministry of Economic Affairs 5. Description of the Invention (1Q) Propyl-5-methylphenyl Propionate [Tri ethylene glycol-bis-3- (3 -t-buty 1-4-hydroxy-5-methylphenyl) propionate], 1,1-bis (2-methyl-4-hydroxy-5-third butylphenyl) butane [l, l-bis ( 2-methyl-4-hydroxy-5-t-butylphenyl) butane] ^ ° The lubricants that can be used in the present invention are representative of the following: metals such as stearic acid, magnesium stearate, zinc stearate, etc. Soap, ethylene bis stearyl amide (EBA), ammonium distearate, ammonium palmitate, butyl stearate, palmityl stearate, polyglycerol monostearate Compounds such as acid esters, n-docosalic acid, stearic acid, polyethylene wax, montan wax, etc. In addition, in the present invention, silicon oil, ultraviolet absorber, dye, and pigment can be added. Etc., and the polystyrene of the present invention The ratio of the average molecular weight Mz of the lipid to the weight average molecular weight Mw is greater than or equal to 2, that is, Mz / Mw > 2, preferably Mz / Mw-2.06 'wherein the ratio of 50,000 to 300,000 in the molecular weight distribution accounts for all More than 53% of the resin, preferably 55%, more preferably 57% or more, and the content of dimer and trimer in the bamboo organisms of the early body of the second woman is less than 8,000 ppm. It is preferably 7,500 ppm or less, and the residual styrene-based monomer is 1,000 ppm or less, and preferably 900 ppm or less. By the limitation of the foregoing conditions, less mold contamination can be obtained without air marks during processing ( Good appearance), and the fluidity and rigidity of the resin are well balanced; on the contrary, when the polystyrene resin of the present invention has a Mz / Mw < 2.0, or a molecular weight distribution ratio of 50,000 to 300,000 accounts for less than 53% of the total resin The content of oligomers such as dimers and trimers in derivatives of styrenic monomers is above 8,000 ppm, or the residual acetophenone monomers are at 1,000 ppm. Page 12 Paper size applies to China National Standard (CNS) A4 (210X297 mm) (please read first Note to fill out the back of this page) - · " Ministry of Economic Affairs Bureau of Standards employees consumer cooperatives printed 1240740 Λ7 ____ B7 V. invention is described in (11) 'is more than' that is unable to achieve the object of the present invention. The preferred method for preparing the polystyrene resin of the present invention is to continuously pump the polymerization reaction solution into the first polymerization tank, and the polymerization tank may be a continuous stirring reaction tank (CSTR) or a plug flow reaction tank (piUg η〇λν react〇). r), the reaction temperature is controlled at 80 ~ 150 ° C, the conversion rate is between 10 ~ 36%; then the solution is sent to the plug flow reaction zone, which can be two to three vertical towers The reaction tank, or horizontal tank reaction tank, has a reaction temperature of 100 ~ 23 ° C, and the final conversion rate can reach 50 ~ 95%, but 60 ~ 90% is preferred. Control of conditions (to avoid the formation of dimers and dimers derived from styrene monomers in large quantities; meticulous reaction temperature control in each reaction tank, reasonable conversion rate distribution, and additions to the polymerization reaction as needed Polyfunctional vinyl monomers or polyfunctional initiators or polyfunctional chain transfer agents to achieve polystyrene resins with a molecular weight of 50,000 to 300,000 and 53% by weight or more of the overall resin. Get good strength and flow Equilibrium, in addition to the adjustment of the initial and final reaction temperature, can produce appropriate high molecular weight polystyrene, by combining with the polyfunctional vinyl monomer or polyfunctional initiator or polyfunctional added in the polymerization reaction as needed The month-b chain transfer agent makes mz / Mw — 2.0, which can greatly improve the moldability and toughness of the product. The resin is also suitable for injection molding of large thin products. The aforementioned high conversion reaction solution is sent to a heating The polymer is dispersed through the heater and heated to 230 ~ 300. (3 high temperature to reduce its viscosity, and then introduced into a devolatilization tank with a vacuum of 5 ~ 200torr. 2. High-vacuum dimers and trimers derived from unreacted monomers and inert solvents and some styrenic monomers, low molecular weight white emu oil ____ page 13 This paper applies to household standards (CNS ) A4 specification (2Κ) × 297 male Chu) " '-Clothing ------ 1T ------ ^ (Please read the precautions on the back before filling this page) 1240740 Λ' B: V. Description of the invention (12) Volatilized, the monomer and inert solvent are separated and then cooled. The condenser is recycled. The molten polymer is continuously extruded by a gear pump at the bottom of the devolatilizing tank. After extruding 2 to 5 bands of rubber through a porous plate, it is cooled, pelletized, and dried to make the final product. Test 1. Tg point (° C) measurement: DSC (Differential Scanning Calorimeter), TA INTRUMENTS DSC-2910. 2. Residual styrene monomer and dimer and trimer derived from styrene monomer Test method: Dissolve the styrene resin in dichloromethane, extract with methanol, take the clear solution from the upper layer after precipitation, and then use Hewlett Packard Company No. 5890A gas analyzer with flame ion detector to analyze and measure the resin solution. . 3. Determination of average molecular weight and molecular weight distribution: According to the gel dialysis method GPC (No. 2487) supplied by Waters Company, and determined according to the following conditions: Column: KD-806M Detector: RI-410, UV-486 mobile phase : THF (flow rate l.Oc.c./min) Printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs (please read the precautions on the back before filling this page) The molecular weight distribution of the resin referred to in the present invention is 50,000 ~ 300,000. More than 53% of all resins are obtained by GPC measurement, that is, in the measurement range of GPC, the total integrated area of resin signals with a molecular weight of 2,000 to 12,000,000 is taken as 100%, of which 50,000 to 300,000 resin points account for the total area Get more than 53%. _Page 14_ This paper size is in accordance with Chinese National Standard (CNS) A4 (210X 297 mm) ί 240740 Λ: B- V. Description of the invention (13 456 mold pollution and appearance: 1/8 inch x 15 cm After continuously shooting 50 molds at 270 ° C on a χ 15 cm plate, observe whether the surface of the plate has oil stains and air marks', and wipe the surface of the mold with cotton to determine the situation of oil pollution. ◎ • Excellent, 0: Good, △: Yes, χ: Melt index (MI, melt index, 200 ° C, 5kg): Tested by ASTM D-1238. Tensile Strength (TSb, Tensile Strength): Tested by ASTM D-638, unit is kg / cm2. [Example] Printed by the Consumers' Cooperative of the Central Bureau of Standards of the Ministry of Economic Affairs [Example 1] In 100 parts by weight of styrene monomer and 3.7 parts by weight of ethylbenzene, 0.03 parts by weight of 2-peroxide is added. The third butyl-hexahydro · terephthalate (BPHTP) as the starter 'and 0.05 parts by weight of ethyiene bis stearyl amine (EBA for short), the above composition is based on 55 liters per hour continuous pumping of three plugs in series with a capacity of 100 liters In the reaction tank, the reaction inlet temperature is maintained at 110, 130 ° C, and 150 ° C. The conversion rate of the first reaction tank is 30%, and the final conversion rate is 76%. It is heated by a heater at 250 ° C and 15 torr. After removing unreacted monomers and inert solvents from the devolatilization equipment operated under vacuum, the measured physical properties are shown in Table 1 after being extruded from the extrusion equipment. [Example 2] Same as the manufacturing method of Example 1, but The feed composition was changed to 100 parts by weight of stupid ethyl monomer monomer, 3.7 parts by weight of ethylbenzene, and 0.016 parts by weight of neopentyl alcohol dipropanthol. 15 pages' Paper size applies to Chinese National Standard (CNS) A4 specifications (210 > < 297 mm) Suppression 1T ------ ^ (Please read the notes on the back before filling this page) Printed by the Staff Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs 1240740 Λ7-~ --- -B7 5 Description of the invention (14)-Methyl vinegar (PGDMA), and 016 parts by weight of u-diperoxy second butyl-3,3, fluorene trimethylcyclohexane (TX-29A) and .01 parts by weight of the third-dodecyl mercaptan (TDM) is a peroxide initiator and a chain transfer agent, and the temperature of the third reaction tank Heating from 15 (TC to 180. (:, conversion of the first reactor was 32%, the final conversion was 82%, the physical properties of the measured sample concentrically in Table I. [third embodiment]

\ J Same as the manufacturing method of Example 2, but the feed composition was changed to 0.03 parts by weight of neopentyl alcohol diacrylate, and the use of the third-dodecyl mercaptan was 1: ^ : It is 0.02 parts by weight, and its physical properties are also measured and listed in Table 1. [Example 4] The feed composition was the same as in Example 2, but the chain transfer agent was changed to 0.01 parts by weight of tris- (3-M-based propionate) trimethylolpropane (TMρτ). The physical properties of the resin are also shown in Table 1. [Example 5] The feed composition of Example 2 was the same, but the starting agent was changed to 025 parts by weight of a third butyl isopropylperoxy carbonate (BPIC). The physical properties were also measured and shown in Table 1. [Example 6] 3.7 parts by weight of ethylbenzene was added to 95 parts by weight of styrene monomer, 2.5 parts by weight of styrene monomer, and 2.5 parts by weight of ethyl methacrylate, and 0.03 parts by weight Di-peroxy third butyl_hexahydro-terephthalate (BPTP), and 0.05 parts by weight of ethylenebisstearylamine are peroxidized. ___ page 16 This paper size is applicable Chinese National Standard (CNS) Α4 specification (210 × 297 male) (Please read the precautions on the back before filling out this page} 、 11 Ϊ240740 V. Λ7 Description of the invention (15 / substance starter 'will form the feed composition to A flow rate of 55 liters / hour was pumped into the reaction tank. The remaining operating conditions are as in Example 1. The measured physical properties are shown in Table 1. [Comparative Example] [Comparative Example 1] 100 parts by weight of styrene monomer, 2 Parts by weight of ethylbenzene and 0.052 parts by weight of ethynylstearylamine as feedstock, in μL The feed composition is pumped into three plug-type reaction tanks (with a volume of 100 liters) connected in series at a flow rate per hour, and the reaction inlet temperatures are maintained at 120 ° C, 135 ° C, and 175C, respectively. It is 38%, and the final conversion rate is 800/0 ′. It is heated by a heater at 245 C and operated under a vacuum of 15 torr. After that, the unreacted monomer and the inert solvent are removed by a devolatilization device, and then extruded. The physical properties of the device after testing are shown in Table 1. [Comparative Example 2] The same manufacturing method as in Example 1, but the feed composition was changed to 100 weight parts of styrene monomer, 3.2 weight parts of ethyl acetate, and 0.02 weight parts. 1,1-di-peroxy first butyl-3,3,5-dimethylcyclohexane, and 0.02 parts by weight of ethylenebisstearylamine as the peroxide initiator In addition, the temperature of the third reaction tank was raised from 15 ° C to 185 ° C, the conversion rate of the first reactor was 30%, and the final conversion rate was 88%. The measured properties are also shown in Table 1. [Comparative Example 3] The same as in Example 1, but the feed composition was changed to 100 parts by weight of styrene monomer, page 17 ^ paper rule ~-a " --- --------- Batch of clothes ---- --1T ------ line (Please read the notes on the back before filling this page) Printed by the Consumers 'Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs 1240740 Printed by the Consumers' Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs A 7 B7 V. Invention Explanation (16) 6.5 weight of ethylbenzene, paraffin oil and 0 parts by weight, and the peroxidation initiator was changed to 002 heavy shame 1,1-mono-peroxide third butyl-cyclohexane (TX_22) and 0.05 parts by weight of ethylenebisstearylamine, in which the temperature of the third reactor is 18 ° C, the conversion rate of the first reactor is 30%, and the final conversion rate is 88%, The physical properties of the manufactured resin after extrusion are shown in Table 1. l *-.

[Comparative Example 4]. The composition was the same as that of Example 3, but the chain transfer agent, dodecanethiol, was changed from 0.02 parts by weight to 0.005 parts by weight. 220 ° C, and the vacuum degree of 25 torr through the devolatilization equipment, the remaining conditions remain unchanged. The physical properties of the resin produced after being extruded from the extrusion equipment are shown in the table. 〇 From the previous examples 1-6, In polystyrene resins, Z average molecular weight Mz and weight average molecular weight Mw, the above Mz / Mw 22.0, and a molecular weight between 50,000 and 300,000 account for more than 53% by weight of all resins, and the resin is derived from stupid vinyl monomers When the total content of dimer and trimer is below 8,000ppm, and the content of styrene-based monomer in the resin is below 1,000ppm, the resin has high fluidity, high tensile strength, and good appearance of the molded product, and The advantages of less mold contamination; and from the test results of Comparative Examples 1 to 4, it is known that when the polystyrene resin does not meet the following conditions: 1) MZ / MW ^ 2.0! 2) The molecular weight of the resin is 50,000 ~ 300,000. 53% by weight or more of all resins; 3) The total content of dimers and terpolymers derived from stupid vinyl monomers in the resin is less than 8,000 ppm; and _______ page 18 ________ This paper size applies to China National Standard (CNS) A4 (210 × 297 mm) Dream ·) (Please read the notes on the back before filling in this page}

1240740 Λ * Β; 5. Description of the invention (17 4) The content of styrenic monomer in the resin is below 10,000; the resin will produce defects such as poor appearance, poor strength and poor fluidity. However, the above are only a few of the preferred embodiments of the present invention. For those skilled in the art, any modifications or alterations made according to the spirit of the present invention should be included in the scope of patent application in this case. Gutter (please read the precautions on the back before filling out this page) A printed ruler from the Consumer Cooperatives of the Central Bureau of Standards of the Ministry of Economic Affairs-one country, one country-China, one suitable fresh S NM 124074α it-listen-TS bpg \ C mlw

MI 今 屮 t Current wife (wt%)

MZ \ M w

Mz (z card state now 屮 t)

Tg rc) S M (I) pm) Effective Daddy (ppm) 1 114 | * 麦 1 i Production per sheet ^^^-^-¾ tt

I 14 # 麦 α 丨 to do

MMA 565 ◎ ◎ 66.1 2.06 538, 500 262, 500 104 500 5000 EBA P05 0.03

BPHTP 3.7 100 580 4.0 ◎ ◎ 57.2 2.23 S5, 400 285, 000 105 600 5500 EBA 05 TDM 0.01 0.016

TX ^ 9A 0.016

PGDMA 3.7 100 590 4 · 1 〇 ◎ 6P3 2.56 7S, 200 298, 000 105 700 6600 EBA P05 TDM P02 0016

TX—29A

PS

PGDA 3.7 100 600

O ◎ ◎ 50 2.56 780,800 305,000 105 700 5500 EBA 0 · 05 TMPT plol 0.016

TX—29A P016

PGMA 3.100 570 4.4 〇 o 620 2.20 605, 000 275, 000

I 105 700 7000 EBA P05 TMPT plol 0025

BPIC 0.016

PGDMA 3.7 100 so 4.3 ◎ ◎ 60.0 2.25 618,700 275, 000 106 500 4200 s 0.05 0.03

BPHTP 3.7 2.5 2.5 95 520 4.0

X

X 58 · 0 1.80 459, 000 255,000 104 600 10500 EBA P05 2.0 100 530 2. > 〇 52.5 1001 547, 800 301,800 105 650 5500 EBA PI025 0.02

TX 丨 29A 3. 100

4100 W

X

X 60.4 2.15 623, 700 289, 600 EBA 1P105 JH SI2 500 i 9000 0.02 TX 丨 22 6.5 100 rrs only w 520 4.4

X 61.2 2C.0 778, 500 299, 500 104 1200 7600 EBA PI05 TDM Pol P016

TX—29A 0.03

PGDA 3.7 100

Claims (1)

0¾¾ Revised specification sheet of invention patent application ^ priced, ~ C8 '~ ^. ~~ --- ~~ 〇 8_____. KK', please patent booth ~-1. A polystyrene resin for injection molding, which It has Z average molecular weight Mζ and weight average molecular weight Mw, the above Mz / Mw ^ 2.〇 (please read the precautions on the back before filling this page), and the molecular weight in the resin is between 50,000 and 300,000. Resin 53 weight percentage or more, and the total content of dimer and dimer derived from styrene monomer in the resin is 8,000 ppm or less, and the content of styrene monomer in the resin is 1,000. ppm or less. 2. The polystyrene resin for injection molding according to item 1 of the scope of the patent application, wherein the polystyrene resin is obtained by polymerizing a styrene monomer as a main component and excluding a rubber component. 3. According to the polystyrene for injection molding described in item 1 of the scope of the patent application, the sassafras month said, ‘The polyethylene resin contains a copolymerization component of a polyfunctional ethylenic monomer. 4. The polystyrene resin for injection molding according to item 3 of the scope of the patent application, wherein the polyfunctional vinyl monomer is neopentyl alcohol diacrylate or neopentyl alcohol diacrylate. 5. The polystyrene resin for injection molding according to item 3 of the scope of the patent application, wherein the polyfunctional vinyl-based monomer accounts for 0.005 to 0.6% by weight of the entire resin. Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 6. According to the polystyrene resin for injection molding described in item 1 of the scope of patent application, where the polystyrene resin is polymerized with a polyfunctional initiator Got. 7. The polystyrene resin for injection molding according to item 1 of the scope of the patent application, wherein the polystyrene resin contains a copolymerization component of a polyfunctional chain transfer agent. Page 20 This paper size applies to China National Standard (CNS) A4 (21 × 297 mm)