KR100785612B1 - Manufacturing method of Impact modifier for flame retardant styrenic resin - Google Patents

Abstract

The present invention relates to a method for preparing an impact modifier of a flame retardant styrene resin having excellent injection appearance characteristics. A) preparing a butadiene-based rubber polymer having an average particle diameter of 1000 to 3000 GPa, a gel content of 70 to 90%, and a swelling index of 12 to 40 step; And b) 40 to 70 parts by weight of the butadiene rubber polymer, and 0.1 to 1.0 parts by weight of a graft crosslinking agent and 30 to 60 parts by weight of a styrene monomer at 40 to 60 ° C. for 2 to 5 hours in a row, reacting, and graft copolymerization. It relates to a method for producing a styrene-containing graft copolymer of the core shell type consisting of.

When the graft copolymer prepared by the production method of the present invention is used as an impact modifier of a flame retardant styrene resin, it is possible to provide a flame retardant styrene resin that is excellent in impact resistance and can be molded without appearance defects under various molding conditions. .

Flame retardant styrene resin, appearance property, graft copolymer, core shell, impact modifier

Description

Manufacturing method of impact modifier for flame retardant styrenic resin having excellent appearance characteristics {Manufacturing method of Impact modifier for flame retardant styrenic resin}

The present invention relates to a method for producing an impact modifier of a flame retardant styrene resin having excellent injection appearance characteristics. Specifically, in the present invention, the styrene-based monomers 30 to 30 containing 0.1 to 1.0 parts by weight of a graft crosslinking agent in 40 to 70 parts by weight of the butadiene-based rubber polymer having an average particle diameter of 1000 to 3000 mm 3, a gel content of 70 to 90%, and a swelling index of 12 to 40 The present invention relates to a method for producing a core-shell type styrene-containing graft copolymer by continuously adding 60 parts by weight at 40 to 60 ° C for 2 to 5 hours to polymerize.

When the graft copolymer prepared by the production method of the present invention is used as an impact modifier of a flame retardant styrene resin, it is possible to provide a flame retardant styrene resin that is excellent in impact resistance and can be molded without appearance defects under various molding conditions. .

Styrene-based resins represented by impact-resistant polystyrene are used in various industrial fields including home appliances and office equipment parts because of their excellent moldability, rigidity, and electrical properties. In particular, recently, it is mainly used for a television housing.

Styrene-based resins have burned properties despite excellent processability and physical properties, and thus have raised safety issues. Thereby, flame retardant and flame retardant synergist are mix | blended with styrene resin, and flame retardance is provided. However, in general, in order to obtain sufficient flame retardancy, the flame retardant formulation has a problem in that the impact resistance is largely lowered and the high impact resistance originally provided by the impact resistant styrene resin is lowered.

The most common method of improving the impact resistance decrease by the addition of a flame retardant is the method of adding an impact modifier, but exhibits a phenomenon in which the main characteristics of the impact resistant polystyrene resin, such as rigidity, flowability, and thermal stability, are lowered. Block copolymers of styrene-butadiene, the most commonly used impact modifiers at present, have the effect of improving the Izod impact strength and the falling impact impact strength, but their stiffness and fluidity are weak, and their molecular structures such as linear, branched and radial As a result, a flow mark is generated on the surface of the injection molding, which causes a problem in implementing a beautiful appearance. Korean Laid-Open Patent Publication No. 2005-0011938 discloses a method in which an styrene-butadiene block copolymer having a fluidity of 1.5 to 15 times higher than that of an impact resistant polystyrene resin is added to improve the impact strength and improve the appearance of an injection molded product. However, this method does not compensate for the disadvantage that the rigidity is lowered. In addition, the superiority cannot be confirmed because the results of comparison with other impact modifiers are not presented.

In addition, Japanese Laid-Open Patent Publication No. 1999-29687 discloses a method of improving the flame retardancy and impact strength of a resin by adding an ethylene-methyl methacrylate copolymer as a method of improving impact resistance. It is lowered and its superiority cannot be confirmed because it does not present a comparison result with other impact modifiers.

In addition, Japanese Laid-Open Patent Publication No. 1999-343373 discloses a method of improving impact resistance by controlling the particle size distribution of rubber particles of the impact resistant polystyrene resin itself. The said method can maintain the outstanding impact resistance after flame retardation by using together the polystyrene resin which has large diameter rubber particle, and the polystyrene resin which has small diameter rubber particle. In addition, Japanese Laid-Open Patent Publication No. 1994-256618 discloses a method of adding polyphenylene ether as a method for improving the Izod impact strength and the falling impact impact strength of a flame retardant resin.

Conventional methods as described above were able to achieve a certain degree of improvement in Izod impact and falling impact of flame retardant styrenic resins, but do not compensate for the disadvantages of lowering rigidity and fluidity. In particular, when the injection molding material is enlarged and complicated, when the impact modifier is applied, the frequency of appearance defects such as a flow mark is high, and there is a need for a method of improving the defect.

Therefore, there is a need for further research on flame retardant high-impact styrene resins that can improve the appearance defects of the injection molding while maintaining the flowability and rigidity.

In order to solve the above problems, an object of the present invention is to provide a method for producing an impact modifier that can improve the impact resistance without maintaining the flowability and rigidity of the flame-retardant styrene resin at the same time without poor appearance.

The above and other objects of the present invention can be achieved by the present invention described below.

The present invention to achieve the above object,

a) preparing a butadiene-based rubber polymer having an average particle diameter of 1000 to 3000 Å, gel content of 70 to 90%, and swelling index of 12 to 40

b) graft copolymerization of 0.1 to 1.0 parts by weight of the graft crosslinking agent and 30 to 60 parts by weight of the styrene monomer in 40 to 70 parts by weight of the rubber polymer of step a).

It provides a manufacturing method comprising a.

When the styrene-containing graft copolymer of the core shell type prepared by the production method of the present invention is used as an impact modifier of a flame retardant styrene resin, it is excellent in impact resistance and can be molded without appearance defects under various molding conditions. Resin can be provided.

Hereinafter, the present invention will be described in detail.

a) Preparation of Butadiene Rubber Polymer

In the present invention, the particle diameter and the gel content of butadiene-based rubber polymer used in the manufacture of the graft copolymer greatly affect the physical properties such as impact strength, flowability, and rigidity of the product, so it is important to select an appropriate particle diameter and gel content. . That is, the smaller the rubber polymer particle diameter is, the better the stiffness and appearance characteristics are, but the impact strength and fluidity are lowered. In addition, when the gel content of the rubber polymer is low, the monomer is swelled in the rubber polymer during the graft reaction of the styrene monomer, and the rubber layer becomes too hard. Possibility to be eccentricity. In addition, if the gel content is too high, the swelling is less enough to cover the core layer of the rubber with a hard polymer, but the impact absorption is lowered when the external impact is lowered, so that the impact resistance is lowered, it is important to select the appropriate gel content.

Therefore, the butadiene-based rubber polymer produced in the present invention is preferably adjusted so that the particle size is 1000 to 3000 Pa, the gel content is 70 to 90%, and the swelling index is 12 to 40. This reaction was carried out by collectively administering 30 to 70 parts by weight of the total 100 parts by weight of the butadiene compound, 0.1 to 2.5 parts by weight of the emulsifier, 0.1 to 1.5 parts by weight of the polymerization initiator, 0.5 to 2 parts by weight of the electrolyte and 75 to 120 parts by weight of ion-exchanged water. In addition, the remaining butadiene compound may be reacted in a batch.

In the present invention, the polymerization temperature during the emulsion polymerization is very important to adjust the gel content and swelling index of the rubber polymer, so that after one step of reaction for 7 to 18 hours at a temperature of 40 to 55 ℃, 12 at a temperature of 55 to 70 ℃ It is preferably prepared by the method of two step reaction for 18 hours.

It is preferable that the butadiene monomer is 1,3-butadiene.

The emulsifier may be alkyl arylsulfonate, alkali methyl alkylsulfonate, sulfonated alkyl ester, fatty acid soap, alkali salt of rosin acid, etc. used in conventional emulsion polymerization. The amount of the emulsifier is preferably 0.1 to 4 parts by weight.

The polymerization initiator may be a water-soluble persulfate, a peroxy compound, an oxidation-reduction system and the like. Specifically, water-soluble persulfates such as sodium or potassium persulfate, cumene hydroperoxide, diisopropyl benzene hydroperoxide, azobis isobutyronitrile, t-butyl hydroperoxide, paramethane hydroperoxide, benzoyl per Fat-soluble polymerization initiators such as oxides, and mixtures of water-soluble radical initiators and oil-soluble radical initiators.

b) preparation of graft copolymers

40 to 70 parts by weight of the rubber polymer prepared above, 0.1 to 1.0 parts by weight of a graft crosslinking agent and 30 to 60 parts by weight of a styrene monomer at 40 to 60 ° C. for 2 to 5 hours in a continuous reaction to react the core shell type styrene-containing graphs To prepare a copolymer. The shell layer serves to impart miscibility with the impact resistant polystyrene resin to the graft copolymer, and allows the rubber polymer core layer to exhibit the impact strength well.

The content of the rubber polymer is preferably in the range of 40 to 70 parts by weight. When the content of the rubber polymer is less than 40 parts by weight, the impact reinforcing effect is insignificant. It cannot be increased, it becomes easy to agglomerate at the time of aggregation and drying after completion of the polymerization, and makes the rigidity of the resin weak.

The grafted styrene-based monomers include side chain alkyl substituted styrenes such as styrene, alpha ethyl styrene and alpha methyl styrene, and nuclear alkyl substituted styrenes such as p-methyl styrene and ot-butyl styrene. Do.

In addition, the graft crosslinking agent should be copolymerized with 0.1 to 1.0 parts by weight during the graft polymerization of the styrene-based monomer, and the usable graft crosslinking monomers include, in addition to divinylbenzene, trivinylbenzene, allyl methacrylate, and triallyl. Allyl esters such as sodium cyanurate, triallyl cyanurate, diallyl maleate, vinyl esters of dibasic acids such as divinyl adipate, vinyl ethers of polyhydric alcohols such as divinyl ether of ethylene glycol, ethylene glycol di Acrylic or methacrylate esters of polyhydric alcohols such as methacrylate, propylene glycol dimethacrylate, ethylene glycol diacrylate, trimerol propane trimethacrylate, and the like, and the like. Increasing the graft ratio by the graft crosslinking agent is advantageous to improve the impact strength, and when the powder is obtained from the latex, the cohesive property is improved, but the impact strength imparting effect is lowered when used at 1.0 parts by weight or more.

The emulsifier used in the graft polymerization is the same as that used when polymerizing the rubbery polymer, and may be selected from various kinds well known in the emulsion polymerization technique, but alkali metal salts of weak acids such as fatty acid salts are preferable. For example, fatty acid potassium salts, potassium oleate salts and the like can be used. As for the usage-amount of the said emulsifier, 0.3-1.0 weight part is preferable. If the amount of the emulsifier is used in a smaller amount than the above range, excessive coagulum is generated during polymerization, which is not productive.

The polymerization initiators used in the graft polymerization are peroxides such as t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide and sodium formaldehyde sulfoxylate, ethylenediamine tetrasodium acetate, ferrous sulfate Oxidation-reduction catalysts such as sodium pyrophosphate and dextrose can be used.

The method of adding the monomer minimizes the formation of coagulum, and a method of continuous administration for 2 to 5 hours is preferable in order to favor the graft reaction.

The graft polymerization is preferably carried out at a temperature of 40 to 60 degrees.

When the styrene-containing graft copolymer is applied to the flame retardant styrene resin, the total impact resistant polystyrene resin is preferably 0.1 to 15 parts by weight, and less than 0.1 parts by weight, when the styrene-containing graft copolymer is 100 parts by weight. If exceeded, the rigidity and flowability are deteriorated.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the examples.

Example 1

(Rubber polymer production)

150 parts by weight of ion-exchanged water, 0.5 parts by weight of buffer solution, 0.2 parts by weight of potassium oleate, 0.0055 parts by weight of ethylenediamine tetrasodium acetate, 0.003 parts by weight of ferrous sulfate, 0.02 weight of sodium formaldehyde sulfoxylate In addition, 0.11 parts by weight of diisopropylbenzene hydroperoxide and 50 parts by weight of monomer 1 and 3-butadiene were collectively administered and reacted at 45 ° C. for 10 hours. 50 parts by weight of the remaining monomers 1, 3-butadiene and 0.7 parts by weight of potassium oleate were collectively administered to polymerize at 55 ° C. for 8 hours to obtain a rubber latex having a particle size of 2000 mm 3, and the final polymerization conversion was 98% by weight.

Gel content and swelling index

The rubber latex was coagulated with dilute acid or metal salt, washed, dried in a vacuum oven at 60 ° C. for 24 hours, the obtained rubber mass was chopped with scissors, and then 1 g of rubber sections was placed in 100 g of toluene for 48 hours. After storage in the dark at room temperature, the sol and gel were separated, and the gel content and swelling index were measured. As a result, the gel content was 82% and the swelling index was 20.

(Manufacture of graft copolymer)

50 parts by weight (solid content) of the prepared rubber latex was introduced into a closed reactor, and the temperature was raised and maintained at 40 ° C. with nitrogen filling. In a separate mixing device, a monomer emulsion was prepared by mixing 50 parts by weight of styrene, 0.5 parts by weight of divinylbenzene, 0.5 parts by weight of potassium oleate, 0.12 parts by weight of t-butyl hydroperoxide, and 30 parts by weight of ion-exchanged water. The monomer emulsion was continuously added to the reactor over 3 hours. At the same time as the monomer emulsion was added, 0.024 parts by weight of ethylenediamine tetrasodium acetate, 0.00125 parts by weight of ferrous sulfate, and 0.125 parts by weight of sodium formaldehyde sulfoxylate were continuously added over 3 hours. 30 minutes after the addition was completed, 0.03 parts by weight of t-butyl hydroperoxide was added and aged at the same temperature for 1 hour to terminate the reaction. After the completion of the polymerization, the particle size was 2500 mm 3, the polymerization conversion was 98%, and the solid content was 40.6%. An antioxidant was added to this latex, coagulated with an aqueous sulfuric acid solution, and then dehydrated and dried to obtain an impact modifier resin powder.

In order to evaluate the prepared impact modifier resin powder 100 parts by weight of impact-resistant polystyrene resin (65IHE Co., Ltd. LG Chem), 3 parts by weight of impact modifier prepared in the present invention, brominated epoxy oligomer and trioxide as flame retardant / flame retardant After adding 27 parts by weight of antimony, 1 part by weight of antioxidant, 1 part by weight of light stabilizer and 1 part by weight of lubricant, a styrene resin composition in pellet form was prepared using a twin screw extruder.

The prepared pellets were injection molded to prepare specimens for physical property evaluation, and their physical properties were evaluated in the following manner.

Izod impact strength: evaluated for 1/8 inch notched specimens by ASTM D256 test method.

* Fluidity (MFR): It was evaluated under the condition of 200 ℃, 5kg load by ASTM D1238 test method.

* Tensile strength (TS): evaluated at a rate of 5 cm / min by the ASTM D638 test method.

* Flexural Strength (FS): evaluated at a rate of 1.5 cm / min by the ASTM D790 test method.

* Falling Impact Strength (FD): A specimen of 3.2 mm in thickness and 80 mm in width was used by ASTM D3763 test method. The weight of the dropping weight was 3.729kg and the hemisphere diameter of the falling weight was 12.5mm. . The dropping weight was dropped at a height of 30 cm to evaluate the impact energy up to the point where the first crack occurred.

* Appearance (FM): The resin was placed in an injection molding machine at 250 ° C. for 15 minutes, and then injected to evaluate the flow traces on the surface of the molding. Criteria are (excellent), ((normal), and Δ (bad).

Example 2

The same method as in Example 1 was carried out except that 0.5 parts by weight of allyl methacrylate was used instead of 0.5 parts by weight of divinylbenzene in preparing the graft copolymer.

Example 3

70 parts by weight of rubber latex, 30 parts by weight of styrene, and 0.3 parts by weight of divinylbenzene were prepared in the same manner as in Example 1.

[Comparative Example 1]

Except for using 2.5 parts by weight of divinylbenzene when preparing the graft copolymer in Example 1 was carried out the same method as in Example 1.

[Comparative Example 2]

The same method as in Example 1 was performed except that the polymerization reaction was performed at 70 ° C. in preparing the graft copolymer in Example 1.

[Comparative Example 3]

30 parts by weight of rubber latex, 70 parts by weight of styrene, and 0.7 parts by weight of divinylbenzene were prepared in the same manner as in Example 1.

[Comparative Example 4]

80 parts by weight of rubber latex, 20 parts by weight of styrene, and 0.2 parts by weight of divinylbenzene were prepared in the same manner as in Example 1.

[Comparative Examples 5 to 7]

In Comparative Example 5, an impact modifier is not applied during compounding, and in Comparative Example 6, instead of applying a styrene-containing graft copolymer of the core shell type provided in the present invention during compounding, a block made of styrene-based and olefin-based elastomers Japanese Asahisa Tuprene 125 (Ashahi, Tufprene 125) was added as a copolymer (SBS), and in Comparative Example 7, a block copolymer (SEBS) consisting of styrene-based and olefin-based elastomers in which the block copolymer was hydrogenated was used. The physical properties were evaluated by adding Asahi Tuptec H1031 (Ashahi, Tuftec H1031).

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Izod (1/8 '') 11.8 11.9 12.7 9.4 9.1 9.2 11.7 MFR 8.1 8.3 7.6 8.2 8.2 8.3 7.3 TS 291 290 282 294 289 305 264 FS 495 497 483 495 490 501 467 FD 8.9 8.9 9.8 7.4 7.2 7.1 8.9 Appearance (FM) ◎ ◎ ◎ ◎ ○ ◎ ○

As shown in Table 1, Examples 1 to 3 using the styrene-containing graft copolymer according to the proper use range and polymerization temperature of the rubber polymer and the graft crosslinking agent presented in the present invention has rigidity, flowability, and appearance of moldings. It can be seen that it is excellent and exhibits high impact characteristics.

division Example 1 Comparative Example 5 Comparative Example 6 Comparative Example 7 Izod (1/8 '') 9.8 7.2 9.7 9.8 MFR 8.1 8.4 8.3 7.4 TS 291 310 294 294 FS 495 511 494 495 FD 8.9 7.0 9.0 8.9 Appearance (FM) ◎ ◎ △ △

As shown in Table 2, Example 1 including the styrene-containing graft copolymer can be seen that the stiffness, flowability and appearance of the molded article is equivalent to Comparative Example 1 and exhibits high impact characteristics. Comparative Examples 6 and 7 showed high impact characteristics, but the appearance of the moldings was poor due to flow marks.

As described above, when the core shell type graft copolymer prepared by the production method of the present invention is used as an impact modifier of a flame retardant styrene resin, appearance defects are maintained even under various molding conditions while maintaining rigidity and flowability. It shows the effect of exerting high impact characteristics without.

While the invention has been described in detail above with reference to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the scope and spirit of the invention, and such modifications and variations are set forth in the appended claims. It is natural to belong.

Claims (6)

In the method for producing an impact modifier of a flame-retardant styrene resin having excellent appearance characteristics through emulsion polymerization, a) preparing a butadiene-based rubber polymer having an average particle diameter of 1000 to 3000 mm 3, a gel content of 70 to 90 wt%, and a swelling index of 12 to 40, and b) graft copolymerization of 0.1 to 1.0 parts by weight of the graft crosslinking agent and 30 to 60 parts by weight of the styrene monomer in 40 to 70 parts by weight of the rubber polymer of step a), Method for producing an impact reinforcing agent for flame retardant styrenic resin excellent in appearance characteristics comprising a The method of claim 1, The grafted styrenic monomers are selected from the group consisting of side chain alkyl substituted styrenes such as styrene, alpha ethyl styrene and alpha methyl styrene, and nuclear alkyl substituted styrenes such as p-methyl styrene and ot-butyl styrene. Manufacturing method of impact reinforcing agent for flame retardant styrene resin having excellent appearance characteristics The method of claim 1, The graft crosslinking agent is, in addition to divinylbenzene, trivinylbenzene, allyl methacrylate, allyl ester such as triallyl isocyanurate, triallyl cyanurate, and diallyl maleate, and dibases such as divinyl adipate. Such as vinyl ester of acid, vinyl ether of polyhydric alcohol such as divinyl ether of ethylene glycol, ethylene glycol dimethacrylate, propylene glycol dimethacrylate, ethylene glycol diacrylate, trimerol propane trimethacrylate A method for producing an impact modifier for a flame retardant styrene resin having excellent appearance characteristics, characterized in that it is selected from the group consisting of acrylic or methacrylic esters of polyhydric alcohols. The method of claim 1, The graft copolymerization is a method of producing an impact modifier for a flame retardant styrene resin having excellent appearance characteristics, characterized in that carried out at a temperature of 40 to 60 degrees. The method of claim 1, In the graft copolymerization step, a graft crosslinking agent and a styrene monomer mixture are continuously added for 2 to 5 hours. A flame retardant styrene resin comprising a core shell type styrene-containing graft copolymer prepared by the method according to claim 1 as an impact modifier.