KR100387311B1 - Branched styrene-based thermoplastic resin and preparation method thereof - Google Patents

Abstract

PURPOSE: A branched styrene-based thermoplastic resin and its preparation method are provided, to obtain a nonlinear styrene-based resin which has an excellent processability even without affecting polymerization stability. CONSTITUTION: The branched styrene-based thermoplastic resin comprises 100 parts by weight of a linear styrene-based resin which comprises 50-100 wt% of an aromatic vinyl compound and 0-50 wt% of a cyano vinyl compound; and 0.05-50 parts by weight of an alkyl-based compound which has at least 4 carbons, comprises some branched chain, a hydroxyl group, an ester group, an ether group, a ketone group or an aromatic group such as a phenyl group, and contains a terminal chlorine or bromine atom. The resin is prepared by the Friedel-Craft alkylation of the linear styrene-based resin and the alkyl-based compound, and has a weight average molecular weight of 50,000-500,000.

Description

Styrene-based thermoplastic resin having a branched structure and a method of manufacturing the same

Field of invention

The present invention relates to a styrene-based thermoplastic resin and a method for producing the same. More specifically, the present invention relates to a styrene-based thermoplastic resin having a branched structure (branched) having excellent workability without affecting the polymerization stability and a method of manufacturing the same.

Background of the Invention and Prior Art

Styrene-based resins have been commercially produced a lot of excellent transparency, thermal stability and mechanical properties, and copolymers with vinyl cyanide compounds, acrylic compounds, or acid anhydride compounds for the improvement of their physical properties. As a method of improving the processability of such a styrene resin, a method of changing the rheological properties by transforming a styrene resin having a linear structure into a nonlinear structure using a polyfunctional compound has been widely used. In the case of the resin having a nonlinear structure, the processability can be increased while maintaining the overall physical properties of the resin, and the thermal stability at the time of processing the resin can be improved.

In order to prepare a styrene resin having a nonlinear structure as described above, US Pat. No. 5,191,040 used a polyfunctional initiator, and US Pat. No. 4,376,847 used a vinyl initiator. However, in the case of the above patents, since the resin is prepared by the bulk polymerization method, contamination occurs on the inner wall of the reactor by gelation during the reaction, and causes a fatal problem in the appearance of the resin after processing.

In order to improve this, two monomers reacting at a high temperature are additionally added during copolymerization of styrene and acrylonitrile, and US Pat. Although there is a method described in Japanese Patent Application Laid-Open No. 59-149912 using a compound, a specific method for preventing problems such as gelation that may occur when synthesizing a nonlinear structure styrene resin is not shown, and it is easy to control the resulting nonlinear structure. The disadvantage is not.

When a polyfunctional monomer is used to prepare a styrene resin having a nonlinear structure, it is difficult to precisely control the structure of the resin, thereby making it difficult to obtain a desired structure, and as a result, it is difficult to control the balance of physical properties of the final resin. In addition, gelation occurs due to the generation of the crosslinked structure, which causes contamination of the inner wall of the reactor, and causes surface defects of the final resin.

The present inventors have developed a styrene resin having a nonlinear structure by Friedel-Craft reaction between a styrene resin and an alkyl compound.

Purpose of the Invention

An object of the present invention is to provide a styrene resin having a non-linear structure that can solve the problems caused by the gelation that may occur when producing a styrene-based resin having a non-linear structure for improving the processability of the styrene resin.

Another object of the present invention is to provide a styrene resin having a nonlinear structure with good processability in which appearance defects of an injection molded product do not occur.

Still another object of the present invention is to provide a method for producing a styrene resin having a non-linear structure, which can easily adjust the branching structure such as the amount and length of branches of the styrene resin having a non-linear structure.

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

Summary of the Invention

The styrene-based thermoplastic resin having a branched structure of the present invention is prepared by a Friedel-Craft alkylation reaction of a linear styrene resin and an alkyl compound composed of 50 to 100% by weight of an aromatic vinyl compound and 0 to 50% by weight of a vinyl cyanide compound. That is, the alkyl compound is alkylated with the linear styrene resin to form a branch. The alkyl compound is used in an amount of 0.05 to 50 parts by weight based on 100 parts by weight of the linear styrene resin, and the branching structure can be adjusted by adjusting the amount of the alkyl compound.

The alkyl compound used in the present invention has 4, preferably 20 or more carbon atoms, and may include aromatic rings such as some branches, hydroxy groups, ester groups, ether groups, ketone groups, or phenyl groups in the compound. It is a substance containing chlorine or bromine atom.

Detailed Description of the Invention

The styrene-based thermoplastic resin having a branched structure of the present invention is prepared by a Friedel-Craft alkylation reaction of a linear styrene resin and an alkyl compound composed of 50 to 100% by weight of an aromatic vinyl compound and 0 to 50% by weight of a vinyl cyanide compound. That is, the alkyl compound is alkylated with the linear styrene resin to form a branch. The alkyl compound is used in an amount of 0.05 to 50 parts by weight based on 100 parts by weight of the linear styrene resin, and the branching structure can be adjusted by adjusting the amount of the alkyl compound.

The linear styrene resin that can be used in the present invention is a thermoplastic resin composed of an aromatic vinyl compound or a vinyl cyanide compound or another monomer copolymerizable with the aromatic vinyl compound is represented by the following structural formula.

In the above formula, R is hydrogen or a methyl group, Ar is a phenyl group, halophenyl group, alkylphenyl group, or alkyl halophenyl group, preferably a phenyl group. Halophenyl is substituted with one or two halogen compounds in the phenyl group, alkylphenyl group is substituted with one or two alkyl groups in the phenyl group, and alkylhalophenyl group is an alkyl group containing a halogen compound or a halogen and an alkyl group substituted together Say that. The vinyl cyanide compound may be one of acrylonitrile, methacrylonitrile, etaacrylonitrile, or a mixture thereof. Moreover, in order to modify the property of a copolymer, the ethylenically unsaturated monomer copolymerizable with the said monomer can be used in 0 to 20weight% of a range. Examples of these are monomers such as esters such as acrylic acid esters and methacrylic acid esters, imides such as maleimide and N-phenylmaleimide, and acid anhydrides such as maleic anhydride.

The alkyl compound used in the present invention has 4, preferably 20 or more carbon atoms, and may include aromatic rings such as some branches, hydroxy groups, ester groups, ether groups, ketone groups, or phenyl groups in the compound. It is a substance containing chlorine or bromine atom.

In the present invention, the linear styrene resin and the alkyl compound form a branched structure by Friedel-Crafts alkylation reaction. Friedel-Crafts alkylation reaction can be readily carried out by one of ordinary skill in the art. Reaction catalysts used for the Friedel-Crafts reaction include aluminum chloride, boron trifluoride, hydrofluoric acid and the like, and most preferably aluminum chloride. In addition, nitrobenzene is mentioned as a reaction solvent.

In the case of using the alkyl-based compound, which is a feature of the present invention, in the preparation of the non-linear styrene resin, it is possible to prevent degradation of the polymerization stability such as gel formation and reactor wall contamination, which may occur due to the use of the multifunctional monomer in the polymerization reaction. The structure can be easily controlled by controlling the amount of alkyl compounds in the synthesis of non-linear styrene resins, and the properties of the desired overall resin by controlling the amounts of non-linear styrene resins when compounding the non-linear styrene resins and the linear styrene resins. Easy to get balance That is, the method for obtaining the desired physical property balance is a method of controlling the amount of the alkyl compound in the synthesis of the non-linear styrene resin, or a method of adjusting the amount of the non-linear styrene resin when compounding with the linear styrene resin. The feature of the present invention is that it is easy to obtain a wide range of physical properties balance. However, when the amount of the alkyl compound is used in the synthesis of the non-linear styrene resin, the molecular weight of the resin may increase, which may lower the processability of the final resin. Therefore, the amount of the alkyl compound is preferably 50 parts by weight or less. Do. In addition, the results showed that the reactivity was greatly reduced when the amount of the alkyl compound is 70 parts by weight or more.

In general, the weight average molecular weight of the nonlinear styrene resin used to improve the processability of the styrene resin is 50,000 to 500,000, preferably 70,000 to 350,000. If the molecular weight of the nonlinear styrene resin synthesized by increasing the amount of the alkyl compound is excessively high, the physical properties of the final resin can be controlled by controlling the amount of each resin through compounding with the linear styrene resin, but the resin itself The high molecular weight of results in degrading the workability.

As described above, the nonlinear styrenic resin prepared according to the present invention has a characteristic of a nonlinear structure that is significantly different from that exhibited by the linear polymer by using an appropriate amount of an alkyl-based compound, especially when compared with a linear polymer having the same molecular weight. It is possible to produce a styrene resin having mechanical properties and showing excellent processability, stretching properties and thermal stability.

The nonlinear styrene-based thermoplastic resin having the branched structure of the present invention can be mixed with a styrene-based resin having a linear structure. At this time, the nonlinear styrene resin is used in the range of 0.1 to 80% by weight. In addition, the non-linear styrene-based thermoplastic resin of the present invention can be used in combination with resins such as ABS, HIPS, PC, PE, PP compatible with this resin. The nonlinear styrene resin of the present invention or a resin containing the same may be used in applications such as foamed resins, films, sheets, and the like.

The invention will be further elucidated by the following examples which are set forth only for the purpose of illustrating the invention and are not intended to limit the scope of the invention.

Examples 1-5

For the synthesis of the nonlinear styrene resin, a reactor equipped with a stirrer, a reflux cooling device, and a hydrochloric acid gas collector was used in a 10 L three-necked flask. After adding 800 parts by weight of nitrobenzene to the flask, 100 parts by weight of the styrene-based resin and the alkyl-based compound were slowly added while varying the content as shown in Table 1 while stirring, and completely dissolved. The alkyl compounds used in Examples 1 to 3 are eicosyl chloride, and the branching structure is the same as CH ₃ (CH ₂ ) ₁₉ Cl. The alkyl compound used in Examples 4 to 5 is CH _3- (CH ₂ ) ₃₀₀ -Cl, which is a chlorine atom introduced from Kraton Liquid L-1203 Polymer of Shell Oil Company. A solution in which 5 parts by weight of aluminum chloride was dissolved in 200 parts by weight of nitrobenzene was slowly added to the nitrobenzene solution over about 1 hour, and then heated to 70 ° C to react for 24 hours. After the reaction was completed, the reaction solution was added dropwise while stirring to a mixed solution of 30 parts by weight of hydrochloric acid and 800 parts by weight of ice water, and the solution was removed using a separatory funnel to remove the upper aqueous layer, and then nitrobenzene solution of nonlinear styrene resin Got it. The solution was washed again several times with distilled water or the like, followed by precipitation using methanol or the like to obtain a synthesized nonlinear styrene resin. Soxhlet extraction was performed for about 3 days using a suitable solvent to remove the unreacted alkyl compound remaining in the resin in the resin thus obtained to obtain a pure non-linear styrene resin, and completely dried at 80 ℃.

The weight average molecular weight and molecular weight distribution of the polymer were measured using gel chromatography. The fluidity index was measured at 200 ° C. and 5 kg, and the results are shown in Table 1. The impact resistance was measured 10 times using a notched specimen (thickness: 1/8 inch) and then averaged. The number of gels was made of a 1mm thick sheet of resin, and the number of gels having a diameter of 1 mm or more was measured in a sheet of 10 cm × 1 m.

Comparative Example 1-2

The same analysis was carried out using a linear styrenic resin having a weight average molecular weight similar to the above example. In Comparative Example 1, the melt index, impact strength, and gel number of the linear styrene resin having a molecular weight of 121,000 and a molecular weight distribution of 1.8 and a molecular weight of 155,000 and a molecular weight distribution of 1.8 were measured.

In Examples 1 to 5 using the nonlinear styrene resins of Table 1, Comparative Examples 1 to 2 of linear styrene resins having the same weight average molecular weight despite the increase in the weight average molecular weight according to the increase in the amount of the alkyl compound It can be seen that the melt index is high compared to the excellent workability. In addition, even in the number of gels showing the surface defect of the resin, the nonlinear styrene resin showed the same level as the linear styrene resin.

Simple modifications and variations of the present invention can be easily made by those skilled in the art, and all such modifications or changes can be seen to be included in the scope of the present invention.

Claims (2)

100 parts by weight of a linear styrene resin composed of 50 to 100% by weight of an aromatic vinyl compound and 0 to 50% by weight of a vinyl cyanide compound; And 0.05 to 50 parts by weight of an alkyl compound having 4 or more carbon atoms and containing an aromatic ring such as a branch, a hydroxy group, an ester group, an ether group, a ketone group or a phenyl group in the compound and containing a chlorine or bromine atom at the terminal; Styrene-based thermoplastic resin having a branched structure, characterized in that the component is Friedel-Crafts alkylation reaction, the weight average molecular weight is in the range of 50,000 to 500,000. The method of claim 1, further comprising 20 to 99.9 wt% of a linear styrene resin selected from the group consisting of ABS, HIPS, PC, PE and PP compatible with the resin based on 100 parts by weight of the total resin. Styrene-based thermoplastic resin.