KR100409077B1 - Method for continuous preparation of rubber-modified styrene resin having superior environmental stress cracking resistance - Google Patents

Abstract

The present invention relates to a method for producing a rubber-modified styrene resin, and more particularly to a continuous method for producing a rubber-modified styrene resin excellent in ESCR (Environmental stress cracking resistance).

The present invention provides a continuous process for producing a rubber-modified styrene resin having excellent ESCR properties by reacting a rubbery polymer with a vinyl monomer, a) i) 4 to 20 parts by weight of a rubbery polymer ii) vinyl monomer 60 To 96 parts by weight, and iii) adding 0.1 to 0.1 parts by weight of a silicone oil having a viscosity of 10 to 20 cst to the solution to prepare a rubber solution; b) the rubber solution is continuously supplied to the first reactor, and the rubber-like polymer and vinyl monomer of the rubber solution are converted into monomer to polymer at a reaction temperature of 120 to 140 ° C. until 10 to 40% by weight. Polymerizing and phase shifting the rubbery polymer to prepare a rubbery polymer mixed reactant; c) continuously supplying the mixed reactants produced in the first reactor to the second, third, and fourth reactors connected in turn from the first reactor, and converting monomer to polymer under reaction temperature conditions of 120 to 140 ° C. Polymerizing to 70 to 90% by weight to prepare a polymer reactant including the rubber component; And d) continuously supplying the reactant produced in the fourth reactor to the devolatilization apparatus and volatilizing the liquid component to separate the polymer including the rubber component from the unreacted monomer. It provides a continuous method of preparation.

The rubber modified styrene resin produced by the manufacturing method of this invention is excellent in ESCR property, excellent in molecular weight, and has the outstanding processing characteristic. In addition, it is possible to manufacture continuously, high production efficiency

Description

METHODS FOR CONTINUOUS PREPARATION OF RUBBER-MODIFIED STYRENE RESIN HAVING SUPERIOR ENVIRONMENTAL STRESS CRACKING RESISTANCE}

[Industrial use]

The present invention relates to a method for producing a rubber-modified styrene resin, and more particularly to a continuous method for producing a rubber-modified styrene resin excellent in ESCR (Environmental stress cracking resistance).

ESCR is known as one of the very important properties in the thermoplastic resin used for food containers. Particularly, when used in food containers or refrigerator wall surfaces, when the resin is extruded in a sheet state, a substance such as a blowing agent or an oil may be cracked or cracked when the residual stress remains. In this case, there is a difference in the degree of occurrence of the break caused by the ESCR property. The material used here is milk fat or oil in the case of food, and is a material used as a foaming agent of polyurethane which is used for insulation of refrigerators, such as halohydrocarbon, chlorofluorocarbon, and cyclopentane.

In preparing rubber modified styrene resins, various methods have been studied to improve ESCR properties. In order to improve the ESCR properties of the moldings, a method of increasing the content of rubbery polymers has been disclosed. US Pat. No. 4,144,204 discloses that the amount of gel produced as a result of controlling the amount of rubber added to the monomer to improve ESCR properties It was said that ESCR property was improved between 28 weight part and 38 weight part. However, when the resin is produced by the above methods, there is a problem in that the tensile strength and the flexural strength of the resin composition are lowered.

In order to solve this problem, U.S. Patent No. 4,777,210 said that increasing the particle size of the polymer can improve ESCR properties without increasing the content of the rubbery polymer. This method is to control the particle size of the rubbery polymer by installing a pre-inversion reactor in a continuous polymerization process.

Alternatively, in order to improve the ESCR properties of such rubber-modified styrenic resins, British Patent Publication No. 2153379A discloses a method of using polyethylene wax as an additive while using polybutadiene having a high molecular weight and at the same time, European Patent Publication US Pat. No. 7,70632A2 discloses a method for simultaneously adding polyisobutylene with mineral oil as an additive, and US Pat. No. 5,543,461 discloses a method for improving ESCR properties using polybutene as an additive. No. 1322399 discloses a method of adding 0.2 to 5 parts by weight of a liquid hydrocarbon telomer having an unsaturated carbon chain. US Pat. No. 3,506,740 uses polypropylene or polybutylene having a molecular weight of 800 to 1600. To improve the ESCR.

However, the above methods are not satisfactory in terms of application of the rubber modified styrene resin, and in particular, it is not possible to produce a rubber modified styrene resin having excellent molecular weight and excellent processing characteristics in continuous production.

In view of the problems of the prior art, an object of the present invention is to provide a continuous production method of a rubber-modified styrene resin having excellent ESCR properties, excellent molecular weight, and excellent processing characteristics.

In the present invention, in order to achieve the above object, in the continuous production method of a rubber-modified styrene resin having excellent ESCR properties produced by reacting a rubber polymer with a vinyl monomer,

a) 4 to 20 parts by weight of a rubbery polymer

Ii) dissolved in 60 to 96 parts by weight of the vinyl monomer,

V) 0.01 to 0.1 parts by weight of a silicone oil having a viscosity of 10 to 20 cst

Adding a to prepare a rubber solution;

b) continuously supplying the rubber solution to the first reactor,

Under the reaction temperature conditions, the rubber polymer and the vinyl monomer in the rubber solution

To the polymer until the conversion rate is 10 to 40% by weight, and the rubber

Phase-transferring the phase polymer to produce a rubbery polymer mixed reactant;

c) the mixed reactants produced in the first reactor are sequentially connected from the first reactor.

Supply continuously to the 2nd, 3rd, and 4th reaction tank, and reaction of 120-140 degreeC

When the monomer-to-polymer conversion is 70 to 90% by weight under temperature conditions

Polymerizing to produce a polymer reactant including the rubber component; And

d) continuously supplying the reactants produced in the fourth reactor to the devolatilization device and

Volatilizing the liquid components to remove polymers containing rubber components from unreacted monomers.

Separating step

It provides a continuous production method of a rubber-modified styrene resin having excellent ESCR properties including.

Hereinafter, the present invention will be described in detail.

The present invention is to include a low viscosity silicone oil in the rubber-modified styrenic resin to be produced, to include large diameter rubber particles in a dispersed phase to have a synergistic effect of ESCR (Environmental stress cracking resistancy), and at the same time excellent It is a continuous manufacturing method of rubber modified styrene resin which made molecular weight and processing characteristics remain as it is.

In the rubber-modified styrene resin produced by the method of the present invention, the rubber particles may contain at least 4% by weight or more in the rubber-modified styrene resin, the size is 10 to 40% by weight of the average particle diameter of 5 to 8 ㎛, An average particle diameter of 3 to 4 μm represents 1 to 50% by weight, and the structure has a cell form. The size of the rubber particles is determined in the first reactor.

As a raw material of the vinyl monomer used in the present invention, at least one monomer selected from styrene, methyl styrene, ethyl styrene, isopropyl styrene, alkyl styrene such as butyl styrene, halogenated styrene such as bromostyrene, and halogenated styrene can be used. , Preferably styrene, α-methylstyrene and Ρ-methylstyrene. The dosage is preferably 60 to 96 parts by weight.

The rubbery polymer which is another raw material is, for example, among polybutadiene, polybutadiene-styrene block copolymer rubber, ethylene-propylene copolymer, ethylene-propylene-terpolymer copolymer rubber, butadiene-acrylonitrile copolymer rubber One or more polymers selected can be used, with the preferred polymer being poly butadiene.

The content of the rubbery polymer in the rubber solution of the present invention is 4 to 20 parts by weight, preferably 6 to 12 parts by weight, and the viscosity of the 5% by weight styrene solution of the polymer used is about 240 cst.

The rubber solution of the present invention is prepared by dissolving a polybutadiene as a rubbery polymer in a styrene monomer, but may further contain other solvents as necessary. The solvent used is, for example, toluene, ethylbenzene, diethylbenzene, ethyl xylene, and the like, preferably ethylbenzene. The input amount may be used in a large amount or a small amount depending on the process conditions, but 0 to 50 parts by weight is preferable in the conventional production with respect to 100 parts by weight of the rubber solution of the vinyl monomer and the rubber polymer.

The additive of the present invention uses a silicone oil, which preferably has a low viscosity of 10 to 20 cst, in particular diphenylsilicone oil. The amount of the silicone oil added in the rubber solution is preferably 0.01 to 0.1 parts by weight based on 100 parts by weight of the rubber solution of the vinyl monomer and the rubber polymer.

Another additive of the present invention may use tertiary dodecyl mercaptan, endodecyl mercaptan, alpha methyl styrene dimer and the like as the molecular weight modifier, preferably tertiary dodecyl mercaptan. The amount of the silicone oil added in the rubber solution is preferably 0.01 to 0.1 parts by weight based on 100 parts by weight of the rubber solution of the vinyl monomer and the rubber polymer.

The present invention will be described in more detail with reference to the following examples and comparative examples. However, an Example is for illustrating this invention and is not limited only to these.

EXAMPLE

Example 1

10 parts by weight of poly butadiene (viscosity 240 cst of 5% styrene solution) was dissolved in 18 parts by weight of ethylbenzene and 72 parts by weight of styrene to prepare a raw rubber solution. The additive was added 0.01 parts by weight of tertiary dodecyl mercaptan, which is a molecular weight regulator, and 0.01 parts by weight of silicone oil (diphenyl silicone oil from Dow Corning, viscosity 20 cst).

In each of the first to fourth reactors, the reaction temperature of each reactor was set to 130 ° C. 135 ° C. 140 ° C. and 145 ° C., and the polymerization solution was continuously supplied from the first reactor to the fourth reactor so that the polymerization solution was continuously supplied.

Finally, in the fourth reactor, the reaction solution is continuously sent to a conventional devolatilization apparatus, and the unreacted monomer and the solvent are separated from the polymer solution at a high temperature of 220 to 240 ° C. and a reduced pressure of 10 to 20 torr, followed by using a gear pump. It discharged, it pelletized, and obtained the rubber modified styrene resin.

Example 2

A rubber modified styrene resin was obtained in the same manner as in Example 1 except that 0.01 parts by weight of diphenyl silicone oil having a viscosity of 10 cst was added as the silicone oil as an additive.

Example 3

A rubber modified styrene resin was obtained in the same manner as in Example 1 except that 0.05 parts by weight of diphenyl silicone oil having a viscosity of 10 cst was added as the silicone oil as an additive.

Example 4

A rubber-modified styrene resin was obtained in the same manner as in Example 1 except that 0.1 part by weight of diphenyl silicone oil having a viscosity of 20 cst was added as the silicone oil as an additive.

Comparative Example 1

A rubber modified styrene resin was obtained in the same manner as in Example 1 except that 0.5 parts by weight of diphenyl silicone oil having a viscosity of 20 cst was added as the silicone oil as an additive.

Comparative Example 2

A rubber modified styrene resin was obtained in the same manner as in Example 1 except that 0.01 parts by weight of diphenyl silicone oil having a viscosity of 1000 cst was added as the silicone oil as an additive.

Comparative Example 3

A rubber modified styrene resin was obtained in the same manner as in Example 1 except that 0.1 part by weight of diphenyl silicone oil having a viscosity of 1000 cst was added as the silicone oil as an additive.

Comparative Example 4

A rubber modified styrene resin was obtained in the same manner as in Example 1 except that 0.1 parts by weight of diphenyl silicone oil having a viscosity of 5000 cst was added as the silicone oil as an additive.

Comparative Example 5

A rubber modified styrene resin was obtained in the same manner as in Example 1 except that 0.1 part by weight of diphenyl silicone oil having a viscosity of 10,000 cst was added as the silicone oil as an additive.

In order to determine the ESCR property, the rubber modified styrene resins of Examples 1 to 4 and Comparative Examples 1 to 5 were each sealed in a sealed container at a temperature of 25 ° C., an exposure time of 1 hour, and a temperature of −20 ° C. After exposure to saturated cyclopentane under temperature conditions and exposure conditions of 24 hours, elongation was measured according to the method of ASTM D-256, and the results are shown in Tables 1 to 2 below. Elongation 1 is measured at 0.5% strain and elongation 2 is measured at 0.7% strain.

TABLE 1

Change in elongation at 25 ° C and 1 hour of cyclopentane exposure

division(%) Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Elongation before exposure 100 102 101 102 102 100 102 101 102 Elongation after exposure 1 98 94 96 97 85 82 85 83 86 Elongation after exposure 2 95 90 93 94 80 78 79 75 78

TABLE 2

Change in elongation at -20 ° C and cyclopentane exposure at 24 hours

division(%) Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Elongation before exposure 103 104 103 102 102 101 100 104 102 Elongation after exposure 1 82 87 83 88 62 65 69 66 68 Elongation after exposure 2 75 79 75 73 58 57 58 60 62

The rubber modified styrene resin produced by the manufacturing method of this invention is excellent in ESCR property, excellent in molecular weight, and has the outstanding processing characteristic. In addition, it is possible to manufacture continuously, high production efficiency

Claims (7)

(correction) In the continuous production method of a rubber-modified styrene resin having excellent ESCR properties produced by reacting a rubbery polymer with a vinyl monomer, a) 4 to 20 parts by weight of a rubbery polymer Ii) dissolved in 60 to 96 parts by weight of the vinyl monomer, V) 0.01 to 0.1 parts by weight of polyorganosiloxane having a viscosity of 10 to 20 cst Adding a to prepare a rubber solution; b) the rubber solution is continuously supplied to the first reactor, and the rubber-like polymer and vinyl monomer of the rubber solution are converted into monomer to polymer at a reaction temperature of 120 to 140 ° C. until 10 to 40% by weight. Polymerizing and phase shifting the rubbery polymer to prepare a rubbery polymer mixed reactant; c) continuously supplying the mixed reactants produced in the first reactor to the second, third, and fourth reactors connected in turn from the first reactor, and converting monomer to polymer under reaction temperature conditions of 120 to 140 ° C. Polymerizing to 70 to 90% by weight to prepare a polymer reactant including the rubber component; And d) continuously supplying the reactants produced in the fourth reactor to the devolatilization device and volatilizing the liquid component to separate the polymer including the rubber component from the unreacted monomer Continuous production method of a rubber-modified styrene resin having excellent ESCR properties comprising a. The method of claim 1, The rubber solution of step a) Iii) continuous of rubber-modified styrene resin having excellent ESCR properties, prepared by further adding 0.01 to 0.04 parts by weight of a molecular weight modifier selected from the group consisting of tertiary dodecyl mercaptan, endodecyl mercaptan, and alpha methyl styrene dimer. Manufacturing method. The method according to claim 1 or 2, The rubber solution of step a) Iii) A continuous process for producing a rubber-modified styrene resin having excellent ESCR properties, which is prepared by further adding 50 parts by weight or less of a solvent selected from the group consisting of toluene, ethylbenzene, diethylbenzene, and ethyl xylene. The method of claim 1, The rubber group of a) step iii) wherein the rubbery polymer is made of polybutadiene, polybutadiene-styrene block copolymer, ethylene-propylene copolymer, ethylene-propylene-terpolymer copolymer, and butadiene- atrylonitrile copolymer A continuous production method of a rubber-modified styrene resin having excellent ESCR properties selected from at least one kind. The method of claim 1, ESCR property wherein at least one vinyl monomer of step a) is selected from the group consisting of styrene, methyl styrene, ethyl styrene, isopropyl styrene, butyl styrene, chloro styrene, bromo styrene, and p-methyl styrene. Excellent process for producing a rubber modified styrene resin. (correction) The method of claim 1, A process for producing a rubber-modified styrene resin having excellent ESCR property, wherein the polyorganosiloxane of step a) is a polydiphenylsiloxane. The method of claim 1, The polymerization of step b) is a continuous production method of a rubber-modified styrene resin having excellent ESCR properties initiated by heating.