KR100215508B1 - The process for manufacturing of thermoplastic resins with high toughness properties - Google Patents

Abstract

The present invention relates to a method for producing a high-stiffness thermoplastic resin, and more particularly, to a method for producing a high-stiffness thermoplastic resin by adjusting the reaction conditions in the first reactor in the process of producing a thermoplastic resin, By controlling the reaction conditions so that the reaction conditions can be reduced. By producing a thermoplastic resin having a solid content of a certain range and a molecular weight falling within a specific range by the polymerization method, the yellowness of the resin is improved and the rigidity is greatly improved, A biaxially oriented polystyrene, a biaxially stretched polystyrene, a resin component of office equipment, and the like.

Description

Method for producing high rigidity thermoplastic resin

The present invention relates to a method for producing a thermosensitive thermosensitive resin, and more particularly, to a method for producing a thermosensitive thermosetting resin, which comprises the steps of adjusting the reaction conditions in the first reactor in the thermoplastic resin production process to significantly increase the residence time, By controlling the reaction conditions so that the reaction conditions can be reduced. By producing a thermoplastic resin having a solid content of a certain range and a molecular weight falling within a specific range by the polymerization method, the yellowness of the resin is improved and the rigidity is greatly improved, A biaxially oriented polystyrene, a biaxially stretched polystyrene, a resin component of office equipment, and the like.

In a general method for producing a highly rigid thermoplastic resin, a reaction is carried out by solution polymerization using a plurality of reactors, and most of the raw material solution is introduced into the first reactor. However, the high-molecular-weight polystyrene having high molecular weight can be obtained by such a production method. However, since a large number of reactors are used, not only the productivity is deteriorated but also the defect occurrence rate is high when the variety is changed. In the conventional solution polymerization method, ethylbenzene or methyl ethyl ketone is used as a solvent. When such an organic solvent is used, polystyrene whose transparency is the first condition due to solvent pollution, .

In the present invention, efforts have been made to produce a thermoplastic resin excellent in transparency (yellowing degree) and greatly improved in rigidity. As a result, a continuous bulk polymerization reaction is performed in the first reactor and the second reactor in place of the method of simultaneously feeding the reactants, and the amounts of the reactants, the residence time, and the polymerization temperature in each reactor are maintained at a certain level, The molecular weight and the yellowness of the thermoplastic resin are maintained at an appropriate level.

Accordingly, it is an object of the present invention to provide a novel production method which can be produced by continuous bulk polymerization of a high molecular weight thermoplastic resin having good yellowing property and excellent rigidity in two reactors.

Fig. 1 is a conceptual diagram of a continuous phase bulk polymerization apparatus used for producing a high-rigidity thermoplastic resin according to the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

1: first reaction vessel 2: second reaction vessel

3: raw material storage tank

The present invention relates to a method for producing a high-stiffness thermoplastic resin by continuous bulk polymerization using a styrene monomer as a raw material, wherein the styrene monomer is reacted in a first reactor and a second reactor And continuously mass-polymerizing the thermoplastic resin.

[Equation 1]

F = F ₁ + F ₂

&Quot; (2) "

1.5? F ₁ / F _2? 3.0

&Quot; (3) "

1.3≤V ₁₁ / V ₁₂ ≤2.3

&Quot; (4) "

2.0≤V ₂₁ / V ₂₂ ≤2.3

In the above equations,

F is the total flow rate of the styrene monomer introduced into the reaction,

F ₁ is the flow rate of the styrene monomer charged into the first reactor,

F ₂ is the flow rate of the styrene monomer charged into the second reactor,

V ₁₁ is the internal content of the first reactor,

V ₁₂ is the internal content of the reaction solution in the first reactor,

V ₂₁ is the content of the second reactor,

V ₂₂ is internal content of the reaction solution in the second reactor.

Hereinafter, the present invention will be described in detail.

The present invention relates to a method for producing a high molecular weight thermoplastic resin having good yellowing property and excellent rigidity by separately introducing a raw material solution into a first reactor and a second reactor at an appropriate ratio.

In the production method of the present invention, the polymerization reaction in the first reactor is a core reaction for polymerizing a high molecular weight thermoplastic resin for producing a high-rigidity resin, and the reaction in the second reactor is continuously transferred from the first reactor Thereby suppressing the production of low molecular weight thermoplastic resin in the reactants of the first reactor and giving an additional reaction to increase the ratio of the final solid content.

A method of manufacturing a high-stiffness thermoplastic resin according to the present invention will be described with reference to FIG. 1 attached hereto. In the following, as an example of the present invention, a method for producing a high-stiffness polystyrene resin by using a styrene monomer as a raw material and a continuous bulk polymerization method is specified.

The first reactor (1) and the second reactor (2) are connected to a raw material storage tank (3) storing a styrene monomer, and are continuously supplied with styrene monomer.

Styrene monomers that can be used in the present invention include side chain alkyl substituted styrenes such as styrene,? -Methyl styrene and? -Ethyl styrene; Nuclear alkyl substituted styrenes such as vinyl xylene, o-t-butyl styrene, p-t-butyl styrene and p-methyl styrene; Halogenated styrenes such as monochlorostyrene, dichlorostyrene, tribromostyrene and tetrachlorostyrene; p-hydroxystyrene; o-methoxystyrene, and the like. Preferably styrene is used.

In the first reactor, the conditions of the equations (1), (2) and (3) are maintained, and the mass rotation of the agitator in the first reactor is adjusted to 30 times / minute to perform continuous bulk polymerization at 110 to 130 ° C.

In the polymerization conditions in the first reactor, the flow rate of the styrene monomer injected into the first reactor and the flow rate (F ₁ + F ₂ ) of the styrene monomer injected into the second reactor are determined so that the total flow rate of the styrene monomer (F 1), and the ratio (F ₁ / F ₂ ) of the flow rate of the styrene monomer injected into the first reactor to the flow rate of the styrene monomer injected into the second reactor is maintained at 1.5 to 3.0. Thus, the two reactors were effectively used to adjust the viscosity to facilitate the transfer of the reactants, and to increase the molecular weight to the maximum. If F ₁ / F ₂ is less than 1.5, the viscosity of the reactant becomes excessively high to cause conveyance defects. As a result, temperature control of the second reactor is difficult, and a large amount of low molecular weight polystyrene is produced in the second reactor. Can not be obtained. If F ₁ / F ₂ exceeds 3.0, there is a problem that high molecular weight polystyrene can not be formed.

The ratio (V ₁₁ / V ₁₂ ) of the internal volume (V ₁₁ ) of the first reactor to the internal volume (V ₁₂ ) occupied by the reaction solution in the first reactor is maintained at 1.3 to 2.3. If V ₁₁ / V ₁₂ is less than 1.3, solid content can not be obtained and the molecular weight is lowered, and a desired resin can not be obtained. If the V ₁₁ / V ₁₂ is more than 2.3, the viscosity becomes excessively high and the load of the agitator is increased to make it difficult to operate. You are at risk because of lack of time to be able.

As a result of carrying out the polymerization reaction in the first reactor at the polymerization reaction temperatures of 110-130 ° C and the conditions of the equations (1), (2) and (3) as described above, A high-rigidity high molecular weight resin having a molecular weight of 30 to 40,000 was obtained.

The polymerized product which has undergone the reaction in the first reactor is continuously supplied to the second reactor to carry out continuous bulk polymerization. In the second reactor, the number of revolutions of the reactor was fixed at 20 times / minute while maintaining the conditions of the above-mentioned formulas (1), (2) and (4), and the continuous bulk polymerization was carried out so that the solid content became 50 to 70% I do.

In the condition of the second reactor, when the ratio (V ₂₁ / V ₂₂ ) of the internal volume (V ₂₁ ) of the second reactor to the internal volume (V ₂₂ ) occupied by the reaction solution is less than 2.0, It is impossible to obtain a resin having high rigidity and it is difficult to control the polymerization temperature due to an increase in calorific value. If V ₂₁ / V ₂₂ is more than 3.0, the content of solid content is decreased, resulting in a loss of productivity and a valuable operation. If the polymerization reaction temperature in the second reactor is maintained below 145 ° C, the productivity tends to decrease. If the polymerization reaction temperature exceeds 170 ° C, the production rate of the high molecular weight polystyrene is low and the desired high stiffness resin can not be obtained.

As described above, the polymerization reaction in the second reactor was carried out under the conditions of Equations 1, 2 and 4 and the polymerization reaction temperature of 145 to 170 ° C, and as a result, a high molecular weight polystyrene was obtained while maintaining a valuable productivity .

In the first reactor or the second reactor, other additives such as molecular weight regulators may be added, which can be easily carried out by those skilled in the art. For example, a release agent, an antistatic agent, an antioxidant and the like may be appropriately added according to the respective applications.

In the second reactor, the reacted reaction product is separated into pellets after separating unreacted monomers through a warmer, a volatilization tank and the like. The final resin product of this pallet type has an average molecular weight of 300,000 to 400,000.

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

The following abbreviations are used in the following embodiments.

F: total flow of styrene monomer injected into the reaction

F ₁ : Flow rate of styrene monomer injected into the first reactor

F ₂ : Flow rate of styrene monomer injected into the second reactor

V ₁₁ : Content of the first reactor

V ₁₂ : Content content of the reaction solution in the first reactor

V ₂₁ : Content of the second reactor

V ₂₂ is the internal content of the reaction solution in the second reactor

[Example 1]

The first reactor (1) and the second reactor (2) are connected to a raw material storage tank (3). The raw material storage tank 3 stores styrene monomer as a raw material.

In the first reactor, polymerization was carried out under the conditions of F = F ₁ + F ₂ , F ₁ / F ₂ = 1.7, and V ₁₁ / V ₁₂ = 1.72. At this time, the number of revolutions of the stirrer was fixed at 30 times / minute, and the polymerization temperature was maintained at 110 占 폚.

The polymerizations of the first reactor were continuously fed to the second reactor in the same manner as the feed rates of the first reactor to perform polymerization.

In the second reactor, polymerization was carried out under the conditions of F = F ₁ + F ₂ , F ₁ / F ₂ = 1.7, and V ₂₁ / V ₂₂ = 2.7. At this time, the number of revolutions of the agitator was fixed at 20 times / minute, and the polymerization temperature was maintained at 155 占 폚.

In the second reactor, a release agent (ZN-ST) was dissolved in a styrene monomer at a concentration of 5% by weight in a separate tank so as to have a final pellet concentration of 8,000 ppm.

The final polymer obtained in the second reactor was continuously sent to the devolatilization process and heated to 245 ° C to remove volatile components such as unreacted monomers, thereby preparing pellets.

[Example 2]

Except that the polymerization conditions in the first reactor were maintained at F = F ₁ + F ₂ , F ₁ / F ₂ = 2.0, and V ₁₁ / V ₁₂ = 1.72.

[Example 3]

Except that the polymerization conditions in the first reactor were maintained at F = F ₁ + F ₂ , F ₁ / F ₂ = 1.7, and V ₁₁ / V ₁₂ = 1.5.

[Example 4]

Except that the polymerization conditions in the second reactor were maintained at F = F ₁ + F ₂ , F ₁ / F ₂ = 1.7, and V ₂₁ / V ₂₂ = 2.9.

[Example 5]

The polymerization was conducted under the same conditions as in Example 1, except that the polymerization temperature of the second reactor was adjusted to 165 ° C.

[Comparative Example 1]

Except that the polymerization conditions in the second reactor were maintained at F = F ₁ + F ₂ , F ₁ / F ₂ = 0, and V ₁₁ / V ₁₂ = 2.7.

[Comparative Example 2]

Except that the polymerization conditions in the first reactor were maintained at F = F ₁ + F ₂ , F ₁ / F ₂ = 1.7, and V ₁₁ / V ₁₂ = 3.0.

[Comparative Example 3]

Except that the polymerization conditions in the second reactor were maintained at F = F ₁ + F ₂ , F ₁ / F ₂ = 1.7, and V ₂₁ / V ₂₂ = 1.5.

[Comparative Example 4]

The polymerization was carried out under the same conditions as in Example 1, except that the polymerization temperature of the second reactor was controlled at 180 캜.

[Experimental Example]

The properties of the thermoplastic resins obtained in Examples 1 to 5 and Comparative Examples 1 to 4 were measured in the following manner, and the results are shown in the following table.

Tensile strength: Measured according to ASTM D638 (speed: 20 mm / min)

· Yellow color: Measured according to JIS K7105

Molecular weight: 5 mg of the sample from the final pellet was sampled, mixed with 5 ml of tetrahydrofuran, placed in a shaker, and completely dissolved by shaking for 30 minutes. Then, it was measured by a gel permeation chromatograph (SPECTAR PHYSICS ANALYTICS).

[Table 1]

The present invention has the effect of efficiently producing a high molecular weight polystyrene having good transparency and high rigidity characteristics by using only two reactors without adding any organic solvent.

Claims (2)

A method for producing a high-stiffness thermoplastic resin by continuous bulk polymerization using a styrene monomer as a raw material, wherein the styrene monomer is continuously introduced into the first reactor and the second reactor under the following conditions (1), (2) The polymerization reaction in the first reactor is carried out at 110 to 130 ° C and the polymerization reaction in the second reactor is carried out at 145 to 170 ° C to obtain a thermoplastic resin having an average molecular weight (Mw) of 30 to 400,000 By weight based on the weight of the thermoplastic resin. [Equation 1] F = F ₁ + F ₂ &Quot; (2) " 1.5? F ₁ / F _2? 3.0 &Quot; (3) " 1.3≤V ₁₁ / V ₁₂ ≤2.3 &Quot; (4) " 2.0≤V ₂₁ / V ₂₂ ≤3.0 In the above equations, F is the total flow rate of the styrene monomer introduced into the reaction, F ₁ is the flow rate of the styrene monomer charged into the first reactor, F ₂ is the flow rate of the styrene monomer charged into the second reactor, V ₁₁ is the internal content of the first reactor, V ₁₂ is the internal content of the reaction solution in the first reactor, V ₂₁ is the content of the second reactor, V ₂₂ is internal content of the reaction solution in the second reactor. The method of producing a high-stiffness thermoplastic resin according to claim 1, wherein the thermoplastic resin has a yellowness index (YI) of 1.0 or less.