TWI555759B - Rubber-modified styrene-based resin - Google Patents

Description

Rubber modified styrene resin

The present disclosure relates to a rubber-modified styrene-based resin, and more particularly to a rubber-modified styrene-based resin having both good fluidity and impact resistance.

The invention relates to a material suitable for preparing plastic molded articles such as electrical equipment, office equipment, automobile parts and household articles, in particular to a rubber modified styrene resin. The present invention also provides a method of preparing the rubber-modified styrene-based resin, and a molded article comprising the rubber-modified styrene-based resin.

Most of the components contained in plastic molded articles for electrical equipment, household goods, and the like are rubber-modified styrene resins, polycarbonate resins (Polycarbonate Resin), and the like. Among them, the rubber modified styrene resin, such as Acrylonitrile-Butadiene-Styrene Resin (ABS), is widely used in electrical appliances, electronic and automotive parts, mainly Good processing, physical and mechanical properties are well evaluated.

However, as the quality requirements of users continue to increase, there is still a need for improvement in impact strength of rubber-modified styrene resins. Wherein, the rubbery graft copolymer is dispersed in the styrene copolymer, and the punching resistance can be obtained. A styrene resin composition. Such a resin composition can be formed into a molded product through various processing and molding methods (for example, one-time processing: injection molding, extrusion molding, and secondary processing: vacuum molding, etc.).

In order to improve the appearance of the gate of injection molded products and to adopt fully automated production, the processing and molding industry is gradually adopting a pin gate for injection molding. This pinhole gate has a very small pore size and viscosity. The higher resin melt does not easily flow through the pores to form, so in order to improve the fluidity requirements of the rubber-modified styrene resin, the injection molding temperature should be relatively increased to avoid reducing the efficiency of production; in addition, due to the increasing emphasis on molding by the processing plant The ease of processing, good physical properties and better impact resistance. Therefore, how to make the rubber-modified styrene-based resin have a good balance of physical properties such as impact strength and fluidity is an urgent problem to be solved in this field.

The first object of the present disclosure relates to a rubber-modified styrene-based resin which has the characteristics of high fluidity and high impact resistance at the same time, and can maintain other physical properties, and can meet the needs of the industry.

According to an embodiment of the present disclosure, there is provided a rubber-modified styrenic resin comprising 72% by weight to 88% by weight of a styrenic copolymer and 12% by weight to 28% by weight of rubber particles. The styrene-based copolymer comprises a first styrene-acrylonitrile copolymer and a second styrene-acrylonitrile copolymer, and the first styrene-acrylonitrile copolymer has a weight average molecular weight of 50,000 to 100,000. The ratio of the weight average molecular weight of the second styrene-acrylonitrile-based copolymer to the weight average molecular weight of the first styrene-acrylonitrile-based copolymer is from 1.4 to 3.5.

A second object of the present invention is to provide a molded article. This molded article was obtained by molding a rubber-modified styrene resin as described above.

A third object of the present invention is to provide a method for producing a rubber-modified styrene-based resin comprising mixing 72% by weight to 88% by weight of a styrene-based copolymer and 12% by weight to 28% by weight of rubber particles. The refining treatment further comprises an extrusion granulation treatment after the kneading, wherein the styrene copolymer comprises a first styrene-acrylonitrile copolymer and a second styrene-acrylonitrile copolymer, The weight average molecular weight of the first styrene-acrylonitrile copolymer is from 50,000 to 100,000, and the weight average molecular weight of the second styrene-acrylonitrile copolymer is relative to the weight of the first styrene-acrylonitrile copolymer. The average molecular weight ratio is 1.4 to 3.5.

In order to better understand the above and other aspects of the present disclosure, the following specific embodiments are described in detail below:

The present disclosure relates to a rubber-modified styrene-based resin which has characteristics of high fluidity and high impact resistance, and can maintain other physical properties, and can meet the needs of the industry.

The contents of the present invention will be described in detail below:

"Rubber modified styrene resin"

According to an embodiment of the present disclosure, a rubber-modified styrenic resin includes 72% by weight to 88% by weight of a styrene-based copolymer and 12% by weight to 28% by weight of rubber particles. Preferably, the content of the rubber particles ranges from 14% by weight to 25% by weight; more preferably, the content of the rubber particles ranges from 18% by weight to 23% by weight; optimally, the content of the rubber particles ranges from 19% by weight to 22% by weight. When the content of the styrene-based copolymer component is less than 72% by weight, there is a lack of fluidity When the content of the styrene-based copolymer component is more than 88% by weight, there is a disadvantage that the impact strength is insufficient.

The rubber-modified styrene-based resin includes a dispersed phase formed of a rubber polymer (rubber particles) to be modified and a continuous phase formed of a styrene-based polymer in which rubber particles are dispersed in a styrene-based polymer. . The method for producing the rubber-modified styrene-based resin is, for example, but not limited to, a bulk polymerization method, a solution polymerization method, a bulk suspension polymerization method, or the like. For example, a rubber-modified styrenic resin can be copolymerized with an aromatic vinyl monomer via an aromatic vinyl monomer such as styrene, α -methylstyrene or p-methylstyrene, and optionally added. The polymerized comonomer is obtained by graft polymerization on a rubber polymer by a conventional method (for example, emulsion polymerization).

In detail, the rubber-modified styrene-based resin can be obtained by graft polymerization of a monomer component of a rubber polymer (solid content, for example, rubber particles) and a styrene-based polymer, wherein styrene polymerization is carried out. The monomer component of the material may comprise a styrene monomer and an acrylonitrile monomer. In the graft polymerization reaction, an emulsifier, a polymerization initiator or a chain transfer agent or the like may be optionally added.

The rubber particles are obtained by an emulsion polymerization method from the rubber component, and optionally other copolymerizable monomers are added to the emulsion polymerization reaction, and are further subjected to a hypertrophy treatment after the emulsion polymerization reaction. Other copolymerizable monomers include, but are not limited to, styrene, acrylonitrile, (meth) acrylate, and the like. The rubber particles include a diene rubber, a polyacrylate rubber, or a polyoxyalkylene rubber.

The diene rubber may be used singly or in combination, and the diene rubber includes, but not limited to, butadiene rubber, isoprene rubber, chloroprene rubber, styrene-diene rubber, acrylonitrile rubber, and the like.

Styrene monomer can be used singly or in combination, and styrene monomer Including but not limited to styrene, α-methylstyrene, α-chlorostyrene, p-tert-butylstyrene, p-methylstyrene, o-chlorostyrene, p-chlorostyrene, 2, 5-Dichlorostyrene, 3,4-dichlorostyrene, 2,4,6-trichlorostyrene or 2,5-dibromostyrene, etc., wherein the styrene monomer is preferably styrene or α. -methylstyrene or a combination of these.

The acrylonitrile-based monomer may be used singly or in combination, and the acrylonitrile-based monomer includes, but not limited to, acrylonitrile, α-methacrylonitrile, or the like, and the acrylonitrile-based monomer is preferably acrylonitrile.

The rubber particles in the rubber-modified styrenic resin preferably have an average diameter of from 0.1 μm to 2.0 μm, more preferably from 0.1 μm to 1.0 μm, still more preferably from 0.2 μm to 0.6 μm. When the average diameter of the rubber particles is less than 0.1 μm, the improvement in impact resistance of the rubber-modified styrene-based resin may be unsatisfactory. When the average diameter of the rubber particles exceeds 2.0 μm, the melt flowability of the rubber-modified styrene-based resin and the appearance of the final molded article made of the rubber-modified styrene-based resin may become poor.

Examples of the rubber-modified styrene-based resin include High Impact Polystyrene (HIPS) resin, acrylonitrile-butadiene-styrene copolymer (ABS), and acrylonitrile. - Acrylonitrile-acrylate-styrene copolymer (AAS), emulsion polymerized rubber graft copolymer (BP), acrylonitrile-ethylene-propylene rubber-styrene copolymer (AES) or methacrylic acid Methyl ester-butadiene-styrene copolymer (MS).

In the present embodiment, specific examples of the rubber-modified styrene-based resin include an acrylonitrile-butadiene-styrene copolymer or an emulsion polymerized rubber graft copolymer.

The rubber modified styrene resin of the present invention can be selectively added with an additive or other polymer to obtain the rubber modified styrene resin of the present invention. Wherein, the additive is, for example but not limited to, an antioxidant, a plasticizer, a processing aid, an ultraviolet stabilizer, a UV absorber, a filler, a strengthening agent, a coloring agent, a lubricant, a charging inhibitor, a flame retardant, and a flame retardant , heat stabilizers, coupling agents, etc. The additive may be added during the above-mentioned polymerization reaction, after the polymerization reaction, before the coagulation, or during the process of preparing the rubber-modified styrene resin by performing the extrusion kneading treatment.

The antioxidant may be used singly or in combination, and the antioxidant is, for example but not limited to, a phenol-based antioxidant, a thioether-based antioxidant, or a phosphorus-based antioxidant. Preferably, the antioxidant is used in an amount of 2 parts by weight or less based on 100 parts by weight of the total of the rubber-modified styrene resin.

The phenolic antioxidant may be used singly or in combination, and the phenolic antioxidant is, for example but not limited to, octadecyl 3,5-bis(1,1-dimethylethyl)-4-hydroxyphenylpropionate ( 3,5-bis(1,1-dimethylethyl)-4-hydroxybenzenepropanoic acid octadecyl ester, model: antioxidant IX-1076), triethylene glycol bis[3-(3-tert-butyl-5-methyl- 4-hydroxyphenyl)propionate], tetrakis[methylene-3-(3,5-bis-tert-butyl-4-hydroxyphenyl)propionate]methane, 2-tert-butyl-6 -(3-t-butyl-2-hydroxy-6-methylbenzyl)-4-methylphenyl acrylate, 2,2'-methylene-bis(4-methyl-6- Tributylphenol) (2,2'-methylenebis(4-methyl-6-tert-butylphenol), type: antioxidant 2246), 2,2'-thiobis(4-methyl-6-t-butyl Phenol), 2,2'-thio-diethylene-bis[3-(3,5-bis-tert-butyl-4-hydroxyphenyl)propionate], or 2,2'-ethane Indoleamine-bis[ethyl-3-(3,5-bis-tert-butyl-4-hydroxyphenyl)propionate].

The thioether-based antioxidant may be used singly or in combination, and the thioether-based antioxidant is, for example but not limited to, distearyl thiodipropionate, dipalmitosulfur dipropionate, pentaerythritol-tetra-( β - dodecamethyl-thiopropionate), or dioctadecyl sulfide, and the like.

The phosphorus-based antioxidant may be used singly or in combination, and the phosphorus-based antioxidant is selected from a phosphite-containing phosphorus-based antioxidant or a phosphate-containing phosphorus-based antioxidant or a combination thereof. The phosphite-containing phosphorus-based antioxidants such as, but not limited to, tris(nonylphenyl) phosphite, dodecyl phosphite, 4,4'-butylene bis(3-methyl-6- Tributylphenyl-bistridecylphosphite), tris(2,4-t-butylphenyl)phosphite, and the like. The phosphate-containing phosphorus-based antioxidant such as, but not limited to, tetrakis(2,4-t-butylphenyl)-4,4'-extended biphenyl phosphate, or 9,10-dihydro-9-oxygen -10-phosphate phenoxy-10-oxygen and the like.

The slip agent may be used singly or in combination, and the slip agent is, for example, but not limited to, metal soap such as calcium stearate, magnesium stearate, lithium stearate, or ethylene bis-stearamide (EBA). ), methylene distearylamine, palmitic acid decylamine, butyl stearate, palmitate stearate, pentaerythritol tetra-fatty acid ester, polypropionic acid tristearate, n-docosanoic acid, hard A compound such as a fatty acid, a polyethylene wax, a octadecanoic acid wax, a carnuba wax, a petroleum wax or the like. Preferably, the amount of the slip agent is in the range of 2 parts by weight or less based on 100 parts by weight of the total of the rubber-modified styrene resin.

The other polymer is, for example but not limited to, polycarbonate, polyamine, polyethylene terephthalate, polybutylene terephthalate, polyphenylene ether, polyvinyl chloride, polymethyl methacrylate , ethylene-methyl methacrylate copolymer, polypropylene, styrene-butadiene block copolymer, hydrogenated acrylonitrile-butadiene copolymer, hydrogenated styrene-butadiene block copolymer, and the like. Preferably, the polymer is used in an amount ranging from 5 parts by weight to 200 parts by weight based on 100 parts by weight of the total of the rubber-modified styrene resin. Parts by weight. The molded article of the rubber-modified styrene-based resin of the present invention is obtained by subjecting a rubber-modified styrene-based resin as described above to a processing and molding process. This processing and molding process can be carried out in a conventional manner and will not be described again.

Hereinafter, the styrene-based copolymer and the rubber particles in the rubber-modified styrene-based resin of the present invention will be further described:

<styrene copolymer>

The styrene-based copolymer comprises a first styrene-acrylonitrile copolymer and a second styrene-acrylonitrile copolymer, and the first styrene-acrylonitrile copolymer has a weight average molecular weight of 50,000 to 100,000. The ratio of the weight average molecular weight of the second styrene-acrylonitrile-based copolymer to the weight average molecular weight of the first styrene-acrylonitrile-based copolymer is from 1.4 to 3.5.

The first styrene-acrylonitrile copolymer and the second styrene-acrylonitrile copolymer of the styrene copolymer each include a styrene monomer unit and an acrylonitrile monomer unit, and are selectively added to other monomers. A mixture of copolymerizable vinyl monomers is formed by polymerization.

In one embodiment, the ratio of the weight average molecular weight of the second styrene-acrylonitrile-based copolymer to the weight average molecular weight of the first styrene-acrylonitrile-based copolymer is, for example, 1.5 to 2.5.

In another embodiment, the ratio of the weight average molecular weight of the second styrene-acrylonitrile-based copolymer to the weight average molecular weight of the first styrene-acrylonitrile-based copolymer is, for example, 1.5 to 2.0.

In one embodiment, the weight ratio of the second styrene-acrylonitrile-based copolymer to the first styrene-acrylonitrile-based copolymer is, for example, 10/90 to 17/83.

In another embodiment, the second styrene-acrylonitrile copolymer is relatively The weight ratio of the first styrene-acrylonitrile-based copolymer is, for example, 10/90 to 15/85.

In one embodiment, the first styrene-acrylonitrile-based copolymer may include, for example, 20% by weight to 38% by weight of the acrylic monomer unit, and the second styrene-acrylonitrile-based copolymer may include, for example, 20% by weight. Up to 38% by weight of an acrylic monomer unit.

In another embodiment, the first styrene-acrylonitrile-based copolymer may include, for example, 25% by weight to 35% by weight of the acrylic monomer unit, and the second styrene-acrylonitrile-based copolymer may include, for example, 25 parts by weight. % to 35% by weight of an acrylic monomer unit.

<Rubber Particles>

The rubber-modified styrenic resin comprises 72% by weight to 88% by weight of a styrene-based copolymer and 12% by weight to 28% by weight of rubber particles; preferably, the content of the rubber particles ranges from 14% by weight to 25% More preferably, the content of the rubber particles ranges from 18% by weight to 23% by weight; optimally, the content of the gel particles ranges from 19% by weight to 22% by weight.

The rubber particles preferably have an average diameter of from 0.1 μm to 2.0 μm, more preferably from 0.1 μm to 1.0 μm, still more preferably from 0.2 μm to 0.6 μm.

"Method for preparing rubber modified styrene resin"

The method for preparing the rubber-modified styrene resin composition in the present embodiment is not particularly limited, and a general mixing method such as uniform mixing of the styrene-based copolymer and rubber particles may be employed, or The first styrene-acrylonitrile-based copolymer is obtained by uniformly mixing the second styrene-acrylonitrile-based copolymer and the rubber particles. The general mixing method includes: dry mixing with a commonly used Hanschel mixer, and then, for example, an extrusion mixer, a kneading machine, or a Banbury mixer. The mixer melts and mixes.

The contents of the relevant components in the examples and the applicable preparation methods are described in detail below. However, it should be noted that the contents of the embodiments are for illustrative purposes only, and the scope of the disclosure is not limited to the described aspects. This disclosure does not show all possible embodiments. Other variations and modifications may be made to the structure without departing from the spirit and scope of the disclosure, so that other embodiments not disclosed in the present disclosure may be applied. Therefore, the description of the specification is for illustrative purposes only and is not intended to limit the scope of the disclosure.

The following describes the preparation method of the rubber particles.

(1) 150.00 parts by weight of 1,3-butadiene, 15.00 parts by weight of potassium persulfate solution (concentration: 1% by weight), 2.00 parts by weight of potassium oleate, 0.13 parts by weight of ethylene glycol dimethacrylate And 190.00 parts by weight of distilled water was reacted at a reaction temperature of 65 ° C for 14 hours to obtain a diene rubber emulsion having a weight average particle diameter of 0.1 μm (conversion ratio of about 94%, solid content of about 36%).

(2) 90.00 parts by weight of n-butyl acrylate, 10.00 parts by weight of methacrylic acid, 0.50 parts by weight of potassium persulfate solution (concentration: 1% by weight), 0.50 parts by weight of sodium lauryl sulfate solution (concentration: 10% by weight) 1.00 parts by weight of n-dodecyl mercaptan and 200.00 parts by weight of distilled water were reacted at a reaction temperature of 75 ° C for 5 hours to obtain a carboxylic acid group-containing polymer flocculant having a conversion of about 95% and a pH of 6.0. Emulsion.

(3) Thereafter, by using 3 parts by weight (dry weight) of a carboxylic acid group-containing polymer flocculant to 100 parts by weight of the diene rubber latex, the obtained rubber emulsion has a pH of 8.5 and its rubber weight The average particle size is about 0.3 micrometers (μm).

(4) further 300.0 parts by weight of the aforementioned hyperplasticized rubber emulsion (dry Heavy), 75.0 parts by weight of styrene, 25.0 parts by weight of acrylonitrile, 2.0 parts by weight of tert-dodecyl mercaptan, 3.0 parts by weight of cumene hydroperoxide, 3.0 parts by weight of ferrous sulfate solution (concentration: 0.2 wt%), 0.9 parts by weight of a sodium formaldehyde sulfoxylate solution (concentration: 10% by weight), and 3.0 parts by weight of an ethylenediaminetetraacetic acid solution (concentration: 0.25 wt%), and the above-mentioned hypertrophized rubber emulsion was styrene. The acrylonitrile copolymer is subjected to graft polymerization to produce a diene rubber graft copolymer. The prepared diene rubber graft copolymer emulsion is coagulated with calcium chloride, and then dehydrated and dried to less than 2% to obtain desired rubber particles (the composition of which is a diene rubber graft copolymer) The weight average particle diameter was 0.31 micrometer (μm) and the rubber content was 75% by weight.

Table 1 below lists the code of the styrene-acrylonitrile-based copolymer used in the examples and the comparative examples, the weight percentage (AN/AS) of the acrylonitrile-based monomer unit to the styrene-acrylonitrile-based copolymer, and the weight. Average molecular weight.

Hereinafter, the preparation method of each styrene-acrylonitrile-based copolymer of Table 1 will be described.

<PN-127-04>

68 parts by weight of styrene, 32 parts by weight of acrylonitrile, and 8 parts by weight of ethylbenzene were mixed, and then mixed with 0.01 part by weight of the third-dodecylmercaptan, and continuously flowed at a flow rate of 35 kg/hr. It was supplied to a fully mixed continuous reactor in which the volume of the reactor was 40 liters, the internal temperature was maintained at 145 ° C, the pressure was maintained at 4 kg/cm ² , and the overall conversion rate was about 55%. After the completion of the polymerization, the obtained copolymer solution was heated by a preheater, and volatile substances such as unreacted monomers and solvents were removed in a vacuum degassing tank. Next, the obtained polymer melt was subjected to granulation to obtain a styrene-acrylonitrile-based copolymer code-named PN-127-04 having a weight average molecular weight of 210,000 and a styrene monomer unit content of 72%. The acrylonitrile monomer unit content was 28%.

The remaining styrene-acrylonitrile-based copolymer is prepared in the same manner as described above, wherein each raw material feed ratio and post-reaction monomer unit content are listed.

<Making rubber modified styrene resin>

The following series discloses several sets of related experiments (including comparative examples and examples) and carries out related physical property tests for illustration. The composition contents and physical property test results of the examples and comparative examples of each group of experiments are recorded in Table 1.

The embodiment 1-1 is taken as an example for illustration.

In the embodiment 1-1, the rubber particles, the first styrene-acrylonitrile copolymer and the second styrene-acrylonitrile copolymer are mixed to form a resin mixture according to the amounts of the components listed in Table 3. The total amount of the resin mixture is 100 weight 2 parts by weight of vinylbisstearylamine, and 1.5 parts by weight of octadecyl 3,5-bis(1,1-dimethylethyl)-4-hydroxyphenylpropionate (3,5-bis(1,1-dimethylethyl)-4-hydroxybenzenepropanoic acid octadecyl ester, model: IX-1076), forming a copolymer mixture. Further, the copolymer mixture was mixed and granulated at 235 ° C by an extruder (manufacturer model: Werner & Pfleidrer ZSK 35) to obtain a rubber-modified styrene-based resin of the present invention. Next, the rubber-modified styrene-based resin was extruded into a test piece at 230 ° C in an injection molding machine (manufacturer model: Zhenxiong SM-90) to obtain a molded article of the rubber-modified styrene-based resin of the present invention, and the analysis thereof was carried out. The results of the physical property evaluation are shown in Table 3.

For the rest of the comparative examples and examples, please refer to the above, and details are not described herein.

<Physical property test of rubber modified styrene resin>

In the experiment, various physical properties of the resins of the comparative examples and the examples were tested, and the contents are as follows.

(1) Melt Flow Index (MVR): Tested at 220 ° C × 10 kg (unit: cm ³ /10 min) in accordance with ASTM D-1238.

(2) Impact resistance test (Charpy): measured by ISO 180 method, using a notched (Notched, opening depth of 2 mm (mm)) 80 mm × 10 mm × 4 mm test piece at 23 ° C (unit , kJ/m ² ). In this test, the higher the measured value, the better the evaluation. The impact strength is preferably >20 kJ/m ² depending on the requirements of the application product.

(3) Tensile strength (Tsy): Tested according to ASTM D-638 standard method, measured at a speed of 50 mm/min, and the unit is MPa.

(4) Tensile strength at break (Tsb): Tested according to ASTM D-638 standard method, measured at a speed of 50 mm/min, and the unit is MPa.

(5) Elongation (EL): Tested in accordance with ASTM D-638, measured at a speed of 50 mm/min, in %.

(6) SP_50 ° C / hr 10 N: measured by the standard method of ASTM-D1525.

For the results of the respective comparative examples and examples, please refer to Tables 3 to 8. Wherein AS1 represents a first styrene-acrylonitrile copolymer, AS2 represents a second styrene-acrylonitrile copolymer, and AS2/AS1 represents a second styrene-acrylonitrile copolymer relative to the first styrene-propylene. The weight ratio of the nitrile copolymer, AS2/AS1 (molecular weight), represents the ratio of the weight average molecular weight of the second styrene-acrylonitrile copolymer to the weight average molecular weight of the first styrene-acrylonitrile copolymer, and RC represents The rubber particles account for the content of the overall rubber modified styrene resin.

as shown in Table 3. When the content of the rubber-modified styrene resin is from 12% by weight to 28% by weight, the impact resistance index and the melt flow index are both greater than 20, and the sum of the two is greater than 55, and other physical properties are consistent. According to the industry demand, the rubber-modified styrene-based resins of Examples 1-1 to 1-5 have characteristics of high fluidity and high impact resistance.

As shown in Tables 4 to 5, the weight average of the second styrene-acrylonitrile copolymer (AS2) in the samples of Comparative Examples 2-1 to 2-2 compared with Examples 2-1 to 2-5. The ratio of the molecular weight to the weight average molecular weight of the first styrene-acrylonitrile-based copolymer (AS1) was less than 1.4 or more than 3.5, while Comparative Example 2-3 did not have the second styrene-acrylonitrile-based copolymer at all ( AS 2), Comparative Example 2-4 did not have the first styrene-acrylonitrile copolymer (AS1) at all. When the weight average molecular weight ratio of AS2/AS1 is less than 1.4, the melt flow index is less than 20, indicating that the fluidity is not good; and when the weight average molecular weight ratio of AS2/AS1 is more than 3.5, the impact resistance is not good. When the weight average molecular weight ratio of AS2/AS1 is, for example, 1.4 to 3.5, the impact resistance index and the melt flow index are both greater than 20, and the sum of the two is greater than 55, and other physical properties are in line with the needs of the industry. The rubber modified styrene resin of 1~2-5 has the characteristics of high fluidity and high impact resistance at the same time.

As shown in Table 6, when the content ratio of AS2/AS1 is, for example, 10/90 to 17/83, the impact resistance index and the melt flow index are both greater than 20, and The sum of the two is greater than 55, and other physical properties are in line with the needs of the industry. The rubber modified styrene resin of Examples 3-1 to 3-4 has the characteristics of high fluidity and high impact resistance.

As shown in Tables 7 to 8, when AN/AS (the weight percentage of the acrylonitrile-based monomer unit to the styrene-acrylonitrile-based copolymer) is, for example, 26% by weight to 35% by weight, the impact resistance index and melting The flow index is greater than 20, and the sum of the two is greater than 55, and other physical properties are in line with the needs of the industry. It is shown that the rubber modified styrene resin of Examples 4-1 to 4-6 has high fluidity and high resistance at the same time. Impact characteristics.

In conclusion, the present invention has been disclosed in the above embodiments, but it is not intended to limit the present invention. A person skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

Claims (10)

A rubber modified styrene resin comprising: 72% by weight to 88% by weight of a styrene copolymer, comprising a first styrene-acrylonitrile copolymer and a second styrene-acrylonitrile copolymer; And 12% by weight to 28% by weight of the rubber particles; wherein the first styrene-acrylonitrile copolymer has a weight average molecular weight of 50,000 to 100,000, and the weight average molecular weight of the second styrene-acrylonitrile copolymer is relatively The ratio of the weight average molecular weight of the first styrene-acrylonitrile copolymer is from 1.4 to 3.5. The rubber-modified styrene resin according to claim 1, wherein the weight average molecular weight of the second styrene-acrylonitrile copolymer is relative to the weight average of the first styrene-acrylonitrile copolymer. The molecular weight ratio is 1.5 to 2.5. The rubber-modified styrene resin according to claim 1, wherein the weight average molecular weight of the second styrene-acrylonitrile copolymer is relative to the weight average of the first styrene-acrylonitrile copolymer. The molecular weight ratio is 1.5 to 2.0. The rubber-modified styrene-based resin according to claim 1, wherein the weight ratio of the second styrene-acrylonitrile-based copolymer to the first styrene-acrylonitrile-based copolymer is 10/ 90~17/83. The rubber-modified styrene-based resin according to claim 1, wherein the weight ratio of the second styrene-acrylonitrile-based copolymer to the first styrene-acrylonitrile-based copolymer is 10/ 90~15/85. The rubber-modified styrene-based resin according to claim 1, wherein the first styrene-acrylonitrile-based copolymer comprises 20% by weight to 38% by weight of an acrylic monomer unit, the second benzene The ethylene-acrylonitrile-based copolymer includes 20% by weight to 38% by weight of an acrylic monomer unit. The rubber-modified styrene-based resin according to claim 1, wherein the first styrene-acrylonitrile-based copolymer comprises 25% by weight to 35% by weight of an acrylic monomer unit, the second benzene The ethylene-acrylonitrile-based copolymer includes 25% by weight to 35% by weight of an acrylic monomer unit. A molded article obtained by subjecting a rubber-modified styrene-based resin according to any one of claims 1 to 7 to a molding process. A method for producing a rubber-modified styrene-based resin according to any one of claims 1 to 7, which comprises from 72% by weight to 88% by weight of a styrene-based copolymer and from 12% by weight to 28% by weight. % of the rubber particles are subjected to a kneading process, wherein the styrene-based copolymer comprises a first styrene-acrylonitrile copolymer and a second styrene-acrylonitrile copolymer, the first styrene-acrylonitrile The weight average molecular weight of the copolymer is from 50,000 to 100,000, and the weight average molecular weight of the second styrene-acrylonitrile copolymer is relative to the weight of the first styrene-acrylonitrile copolymer. The ratio of the average molecular weight is 1.4 to 3.5. The preparation method according to claim 9, further comprising an extrusion granulation treatment after the kneading.