KR100749665B1 - Branched Styrenic Thermoplastic Resin Having a Excellent Productivity and Preparation Method Thereof - Google Patents

Abstract

The present invention provides a branched styrene comprising polymerizing a mixture comprising (A) 100 parts by weight of an aromatic vinyl compound, (B) 0.001 to 3 parts by weight of a polyfunctional vinyl compound and (C) 0.001 to 0.3 parts by weight of a polyfunctional initiator. It relates to a method for producing a thermoplastic resin. According to the present invention, a styrene-based thermoplastic resin having a branched structure having excellent workability in which the chain entanglement effect is maximized is manufactured.

Styrene-based thermoplastic resin, branch structure, processability

Description

Branched Styrenic Thermoplastic Resin with Excellent Processability and Its Manufacturing Method {Branched Styrenic Thermoplastic Resin Having a Excellent Productivity and Preparation Method Thereof}

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 provides a method for producing a styrene-based thermoplastic resin, using a polyfunctional initiator and a polyfunctional vinyl compound at the same time does not generate a gel during the polymerization process, the melt viscosity and impact strength through the branched structure introduced The present invention relates to a branched styrenic thermoplastic resin having excellent processability and a method of manufacturing the same.

Background of the Invention

In general, styrene-based thermoplastic resins are commercially manufactured due to their excellent transparency, thermal stability, mechanical properties, etc., and have excellent mechanical properties and excellent appearance, so they can be processed alone or mixed with rubber-reinforced styrene-based resins. It is widely used in magnetic parts, office equipment and automobile parts. In general, when the molecular weight of the styrene-based thermoplastic resin is increased, mechanical properties such as impact strength are increased, but due to the increased molecular weight, the melt viscosity increases during processing of extrusion, injection, etc. I can't. Many ways to improve the processability while maintaining the mechanical properties such as impact strength of the styrene-based thermoplastic resin has been studied a lot, one of them is to produce a styrene-based thermoplastic resin having a branched structure to convert the rheological properties Many methods are used.

Styrene-based thermoplastic resins are not easy to introduce a branched structure for improving workability, such as reduced melt viscosity compared to other olefinic resins. JD Ferry's “Viscoelastic Properties of Polymers” (3rd ed., John wiley and Sons, New York, 1980) suggests the minimum molecular weight for entanglement of various types of polymer resins. The chain entanglement molecular weight of was about 18700. That is, in the case of styrene resin, since the chain molecular weight is relatively larger than other types of resins, it is not easy to form a branched structure having an appropriate molecular weight that is easy to be extruded and injected by a general method. For example, in the case of polyethylene, the chain entanglement molecular weight is about 1100, and it is possible to reach the chain entanglement molecular weight when about 40 ethylene units are bonded by polymerization, and in the case of polypropylene, about 70 propylene units are polymerized. When bound, it is possible to reach chained molecular weight. However, in the case of polystyrene, it is possible to reach chain entanglement molecular weight when about 180 styrene units are bonded by polymerization. However, in general, commercial radical polymerization methods of styrene resins, in general, chain entanglement occurs in a molecular weight region far higher than the minimum molecular weight at which styrenic chain entanglement can occur. Since the increase in melt viscosity is greater than the decrease in melt viscosity due to the branching structure, the effect of improving workability due to the branching structure is very small.

In order to manufacture a styrene resin having a branched structure as described above, US Pat. Nos. 6,608,141, 6,433,092, and 5,191,040, etc., use a multifunctional initiator, and US Pat. No. 4,376,847 uses a vinyl initiator. Presented. However, when preparing a styrene-based compound using a polyfunctional initiator or a vinyl-based initiator, the radical decomposition reactivity of each functional group due to the radical decomposition mechanism of the initiator causes the decomposition reaction of the other functional groups due to the decomposition reaction of other functional groups of the same molecule. Due to the drastic decrease in speed, the branching structure formation efficiency is drastically reduced, and the melt viscosity due to the branching structure is also exhibited from a very high molecular weight.

In addition, US Pat. Nos. 5,489,652, 5,059,667, and Republic of Korea Patent No. 10-0474830 are characterized by using a polyfunctional vinyl compound to achieve the above object. However, since polyfunctional vinyl compounds are mixed with styrene vinyl compounds and participate in a polymerization reaction at the same time, gelation may occur during resin production, and the gel may contaminate the inner wall of the reactor and adversely affect productivity. However, due to the local crosslinking structure inside the resin, the surface of the final product has a problem.

In order to improve the above problem, Korean Patent No. 10-0387311 discloses a method for producing a styrene-based thermoplastic resin having a branched structure by a Friedel-Craft alkylation reaction of an alkyl compound substituted with a linear styrene-based thermoplastic resin and a halogen compound. However, there is a disadvantage in that an additional process is required to recover / treat halogen gas generated by side reaction with the used catalyst.

On the other hand, when a branched structure having a sufficient length is introduced into the styrene-based thermoplastic resin, it is possible to improve workability while maintaining mechanical properties such as impact strength. In other words, if the chain entanglement of the branched chain is present at the same time in addition to the chain entanglement caused by the main chain, it is expected to improve the mechanical properties.As a high shear force is applied at the time of processing, the entangled chain is released to obtain a suitable viscosity for processing. This is because it has rheological properties. Since the linear styrene thermoplastic resin having a very high molecular weight has many chain entanglements due to the main chain, the impact strength is excellent, but the entangled main chain is hardly released to the extent that the workability is good, resulting in poor workability. In contrast, the branched styrene-based thermoplastic resin having the same molecular weight has an excellent impact strength because both the main chain and the branched chain have chain entanglement due to the branched chain despite the relatively low molecular weight of the main chain. The processability is improved due to the molecular weight of the main and branched chains sufficient to loosen the chain entanglement.

An object of the present invention is to provide a branched styrene-based thermoplastic resin composition excellent in workability having high fluidity.

Another object of the present invention is to provide a branched styrene-based thermoplastic resin composition excellent in workability having a high impact strength.

Still another object of the present invention is to provide a method for producing a branched styrene thermoplastic resin composition having excellent appearance by preventing gelation.

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

Summary of the Invention

The present invention provides a branched styrene comprising polymerizing a mixture comprising (A) 100 parts by weight of an aromatic vinyl compound, (B) 0.001 to 3 parts by weight of a polyfunctional vinyl compound and (C) 0.001 to 0.3 parts by weight of a polyfunctional initiator. The present invention relates to a thermoplastic resin and a method of manufacturing the same.

Hereinafter, specific contents of the present invention will be described in detail below.

Detailed Description of the Invention

The branched styrene resin having excellent processability of the present invention is charged with 0.001 to 3 parts by weight of a polyfunctional vinyl compound based on 100 parts by weight of a raw material consisting of 60 to 100 parts by weight of an aromatic vinyl compound and 0 to 40 parts by weight of a vinyl cyanide compound. And it can be prepared by further adding 0.01 to 0.3 parts by weight of the polyfunctional initiator after copolymerization.

As the aromatic vinyl compound which can be used in the present invention, styrene, α-methyl styrene, vinyl toluene, t-butyl styrene, chloro styrene and substituents thereof are preferable, more preferably styrene.

Vinyl cyanide compounds include acrylonitrile, methacrylonitrile, etaacrylonitrile, and the like, which may be used alone or in a mixture thereof, preferably acrylonitrile.

The aromatic vinyl compound and the vinyl cyanide compound may be suitably used in the range of 60 to 100 parts by weight and 0 to 40 parts by weight, respectively. The component ratio of the finally obtained polymer is greatly changed, making it difficult to achieve the desired physical properties.

Examples of the polyfunctional vinyl compound that can be used in the present invention include ethylene dimethacrylate, diethylene glycol methacrylate, triethylene glycol dimethacrylate, trimethylene propane trimethacrylate, trimethylene propane triacrylate, 1, 3-butanediol methacrylate, 1, 6- hexanediol dimethacrylate, allyl acrylate, etc. are mentioned.

The content of the polyfunctional vinyl compound is suitably 0.001 to 3 parts by weight, more preferably 0.003 to 1 part by weight based on 100 parts by weight of the mixture of the aromatic vinyl compound and the vinyl cyanide compound. When the total content of the multifunctional vinyl compound is less than 0.001 parts by weight, the chaining effect due to the branched structure does not appear sufficiently, and when it exceeds 3 parts by weight, the molecular weight rapidly increases or the crosslinking reaction proceeds to cause gelation. This leads to problems such as deterioration and contamination of the reactor inner wall and uneven surface of the final product.

Polyfunctional initiators that can be used in the present invention include 2,2-bis (4,4-di (t-butylperoxy) cyclohexyl) propane, tri (t-butylperoxy) triazine, tri (t-butyl Peroxycarbonate-based compounds such as peroxy) trimeliat or polyether poly-t-butylperoxy carbonate and alkylperoxy-alkylfumar such as t-butylperoxy methylfumarate and t-butylperoxy ethylfumarate The rate type compound etc. are mentioned. Moreover, as a multifunctional initiator used by this invention, brand name JWEB50, brand name Pertetra-A, etc. are mentioned.

The content of the multifunctional initiator is suitably 0.001 to 0.3 parts by weight, more preferably 0.03 to 0.1 parts by weight based on 100 parts by weight of the mixture of the aromatic vinyl compound and the vinyl cyanide compound. If the content of the polyfunctional initiator is less than 0.001 part by weight, it is not suitable for preventing gel generation due to its ineffective effect as an initiator. If the content of the polyfunctional initiator is more than 0.3 part by weight, there is a problem in controlling the degree of polymerization and controlling the molecular weight to exhibit the desired physical properties. There may be.

The weight average molecular weight of the branched styrene-based thermoplastic resin excellent in processability of the present invention is preferably about 80,000 to 300,000, more preferably 100,000 to 200,000. If the weight average molecular weight is less than 80,000, the molecular weight is too low, the mechanical properties are lowered. If the weight average molecular weight is more than 300,000, it is possible to produce a styrene-based thermoplastic resin having a branched structure, but the melt viscosity is rapidly increased to actually process It may be disadvantageous that it is difficult to do.

The present invention can be prepared by known polymerization methods such as bulk polymerization, solution polymerization and suspension polymerization. However, due to the characteristics of the multifunctional initiator, a multifunctional initiator which is started at a high temperature is common, and since the decomposition of each functional group occurs sequentially, the polymerization reaction is controlled to increase the initiation efficiency of the multifunctional initiator and to make the copolymerization of various components more effective. Relatively easy solution polymerization is most suitable.

Any organic solvent may be used as long as the organic solvent used for solution polymerization is inert to the reaction and can dissolve both the raw material monomer and the polymerization product. As such an organic solvent, aromatic hydrocarbons such as various alcohols, petroleum ethers and ethylbenzene, halides such as carbon tetrachloride and chloroform, and ketones such as methyl ethyl ketone are suitable. In addition, these can be used individually or in mixture of 2 or more types.

The amount of the organic solvent can be appropriately adjusted in consideration of the viscosity lowering effect in the reaction system, but the ratio of the organic solvent to the monomer and organic solvent mixture is in the range of 10 to 30% by weight. If it is less than 10% by weight, it is not preferable to increase the viscosity in the reactor sharply, and if it exceeds 30% by weight, it is not economical to reduce the effective reaction volume of the reactor or to complicate and enlarge the devolatilization mechanism and recovery apparatus.

The present invention can be better understood by the following examples, which are intended to illustrate the invention and are not intended to limit the scope of protection defined by the appended claims.

Example

Example  One

In a fully mixed stirred reactor in which two reactors having a reactor content of 2000 ml were connected in series, trimethylene propane triacrylate, which is a polyfunctional vinyl compound based on 75% by weight of styrene, 25% by weight of acrylonitrile and 100 parts by weight of the raw material ( TMPTA) 0.03 parts by weight, 0.03 parts by weight of multi-functional monoperoxycarbonate (JWEB50) and 0.2 parts by weight of the molecular weight regulator t-dodecylmercaptan in a feedstock tank to fully mix and stir these mixed liquids at 1.0 Kg / hr rate. Fed to the reactor continuously. A polymerization reaction solution was continuously made by advancing the polymerization conversion rate to 70% with the polymerization reaction temperature of the first reactor being 120 ° C and the polymerization reaction temperature of the second reactor being 140 ° C. Subsequently, a continuous polymerization reaction solution was continuously supplied to a devolatizer of 240 ° C. and 30 Torr to remove unreacted monomers and organic solvents, and then branched styrene having excellent workability in pellet form by using a gear pump. After preparing the thermoplastic resin and measuring the physical properties, the results are shown in Table 1 below.

Example  2

Branched styrene was prepared in the same manner as in Example 1, except that 0.03 parts by weight of trimethylene propane trimethacrylate (TMPTMA), a polyfunctional vinyl compound, was added to 100 parts by weight of the aromatic vinyl compound and the vinyl cyanide compound. The thermoplastic resin was prepared, and the results are shown in Table 1 below.

Example  3

A branched styrene-based compound was prepared in the same manner as in Example 1, except that 0.5 part by weight of trimethylene propane triacrylate (TMPTA), a polyfunctional vinyl compound, was added to 100 parts by weight of the aromatic vinyl compound and the vinyl cyanide compound. A thermoplastic resin was prepared, and the results are shown in Table 1 below by measuring physical properties.

Example  4

A branched styrene thermoplastic resin was prepared in the same manner as in Example 1, except that 0.05 part by weight of a multi-functional monoperoxycarbonate (JWEB50) was added to 100 parts by weight of the aromatic vinyl compound and the vinyl cyanide compound. It was measured, and the results are shown in Table 1 below.

Comparative Example  One

Styrene-based thermoplastics in the same manner as in Example 1, except that in Example 1, trimethylene propane triacrylate (TMPTA) and a multi-functional monoperoxycarbonate (JWEB50) were not used at all. Resin was prepared, and the physical properties were measured and the results are shown in Table 1 below.

Comparative Example  2

A styrene-based thermoplastic resin was prepared in the same manner as in Example 1, except that no multi-functional monoperoxycarbonate (JWEB50) was used in Example 1, and the physical properties thereof were measured and the results are shown in Table 1 below. Indicated.

Comparative Example  3

A styrene-based thermoplastic resin was prepared in the same manner as in Example 1, except that in Example 1, trimethylene propane triacrylate (TMPTA), a polyfunctional vinyl compound, was not used at all, and the physical properties thereof were measured. 1 shows the result.

Comparative Example  4

In Example 1, 0.01 parts by weight of trimethylene propane triacrylate (TMPTA), which is a polyfunctional vinyl compound, and 100 parts by weight of an aromatic vinyl compound and a vinyl cyanide compound, and a multi-functional monoperoxycarbonate (JWEB50) A branched styrene-based thermoplastic resin was prepared in the same manner as in Example 1 except that 0.40 parts by weight of the resin was added. The results are shown in Table 1 below.

Property measurement method

① Mw: Elution curve of the sample was obtained through normal temperature gel permeation chromatography (GPC), and the relative weight average molecular weight was calculated based on the standard polystyrene polymer.

② Impact strength: measured by the standard method of ASTM D256A.

③ Spiral Flow: After the mold was formed with a spiral flow path in a 75 ton, 3 ounce injection molding machine, the maximum injection pressure / speed was applied at a temperature of 210 ° C. and the sample was injected and cooled.

④ Gel%: After dissolving the sample in acetone and centrifuging to separate the insoluble content and weighed, the weight percent of the initial sample weight was calculated.

TABLE 1

Referring to Table 1, in Examples 1 to 4 using the polyfunctional initiator in copolymerizing the polyfunctional vinyl compound, it can be observed that it has a high fluidity and impact strength, and a low gel content.

On the other hand, Comparative Examples 1 to 3, which do not use the polyfunctional vinyl compound and the polyfunctional initiator at the same time, and Comparative Example 4 used beyond the preferred content of the present invention have relatively low fluidity and impact strength, and have a lot of gelation. You can see the progress.

The present invention provides a method for producing a branched styrene-based thermoplastic resin excellent in processability having high fluidity and impact strength, and preventing gelation by using a polyfunctional vinyl compound and a polyfunctional initiator at the same time. Produces the effect.

Simple modifications and variations of the present invention can be readily used by those skilled in the art, and all such variations or modifications can be considered to be included within the scope of the present invention.

Claims (7)

(A) 100 parts by weight of aromatic vinyl compound; (B) ethylene dimethacrylate, diethylene glycol methacrylate, triethylene glycol dimethacrylate, trimethylene propane trimethacrylate, trimethylene propane triacrylate, 1,3-butanediol methacrylate, 1, 0.001 to 3 parts by weight of a polyfunctional vinyl compound selected from the group consisting of 6-hexanediol dimethacrylate and allyl acrylate, and (C) 2,2-bis (4,4-di (t-butylperoxy) cyclohexyl) propane, tri (t-butylperoxy) triazine, tri (t-butylperoxy) trimeliat or poly 0.001 to 0.3 parts by weight of a polyfunctional initiator selected from the group consisting of ether poly-t-butylperoxy carbonate, t-butylperoxy methylfumarate and t-butylperoxy ethylfumarate; Method for producing a branched styrene-based thermoplastic resin, characterized in that for polymerizing the mixture consisting of. The method for producing a branched styrene thermoplastic resin according to claim 1, wherein the aromatic vinyl compound (A) further comprises 0 to 40% by weight of a vinyl cyanide compound. The branched styrenic thermoplastics according to claim 1, wherein the aromatic vinyl compound (A) is selected from the group consisting of styrene, α-methyl styrene, vinyl toluene, t-butyl styrene, chloro styrene, and substituents thereof. Method for producing a resin. The method of claim 2, wherein the vinyl cyanide compound is selected from the group consisting of acrylonitrile, methacrylonitrile, etaacrylonitrile, and mixtures thereof. delete delete The branched styrene-based thermoplastic resin produced by the manufacturing method according to any one of claims 1 to 4, wherein the weight average molecular weight is 80,000 to 300,000.