KR100464697B1 - Process of High Flow Thermoplastic Resin Having Good Moldability - Google Patents

Abstract

In the high flow thermoplastic resin of the present invention, the total flow rate of the styrene monomer to the first and second reactors in the first reactor is F, the total flow rate to the first reactor is F ₁ , and the total flow rate to the second reactor. F ₂ , when the reactor volume of the first reactor is V ₁ and the volume of the reaction solution in the first reactor is V ₁ ′, F = F ₁ + F _2, 6.2 ≤ F ₁ / F ₂ ≤ 7.2, 2.4 Continuous bulk polymerization under the condition of? V ₁ / V ₁ '? 3.0; When the contents of the reactor of the second reactor in the second reactor is V ₂ , and the contents of the reaction solution in the second reactor are V ₂ ′, 2.4 ≤ V ₂ / V ₂ '≤ 4.8, F = F ₁ + F ₂ Continuous bulk polymerization by continuously adding 2.0 to 2.5% by weight of a hydrocarbon compound on a final pellet basis under the condition of; The unreacted monomer is separated from the polymer produced from the second reactor and then cut into pellets. The average molecular weight is 18 to 250,000, the fluidity is 9.5 to 12.0, and the yellowness is 1.0 or less.

Description

Process of High Flow Thermoplastic Resin Having Good Moldability

Field of invention

The present invention relates to a method for producing a high flow thermoplastic resin having excellent release properties. More specifically, the present invention controls the residence time by adjusting the reaction conditions in the first reactor, the reaction conditions to adjust the reaction conditions to reduce the high temperature maintenance and reaction time in the second reactor and solids (polystyrene) content by continuous bulk polymerization By producing a thermoplastic resin having a certain range and a molecular weight in a specific range, not only the yellowness is good and the fluidity is excellent, but also the releasability is greatly improved, thereby manufacturing food and beverage containers, audio product cases, refrigerator internal parts, and general merchandise containers. A method for producing a high flow thermoplastic resin useful in the present invention.

Background of the Invention

In general, high-flow polystyrene has been used to manufacture food and beverage containers, audio product cases, refrigerator internal parts, and general merchandise containers. Conventional techniques for producing such high-flow polystyrene, using a plurality of reactors, the production process proceeds to solution polymerization, there is a method of polymerizing all the raw material solution to the first reactor, the methods are Japan and the United States Many are known through patent documents.

However, according to the above method, it is possible to obtain polystyrene having good fluidity, but there are disadvantages in that the number of reactors not only decreases productivity, but also increases the amount of defects when breeding. In addition, since the reaction is carried out by solution polymerization using solvents (EB, MEK), polystyrene, which has transparency as the best condition, brings about lowering of the product.

In order to solve the problems of the prior art, the present inventors have developed a method for producing a polystyrene resin having good yellowness and excellent fluidity by continuous bulk polymerization in two reactors.

An object of the present invention is to provide a method for producing a thermoplastic resin excellent in fluidity.

Another object of the present invention is to provide a method of producing a high flow thermoplastic resin useful in the manufacture of food and beverage containers, audio product cases, refrigerator internal parts, general merchandise containers, etc., as well as good yellowness and excellent fluidity. It is for.

Both the above and other objects of the present invention can be achieved by the present invention described below. Hereinafter, the content of the present invention will be described in detail.

1 is a schematic diagram schematically showing a continuous block polymerization apparatus for producing a high flow thermoplastic resin having excellent release properties according to the present invention.

Brief description of the main symbols in the drawing

1: total flow rate (F) in which styrene monomer is introduced into the first and second reactors

2: total flow rate of the styrene monomer to the first reactor (F ₁ )

3: total flow rate of the styrene monomer to the second reactor (F ₂ )

4: reactor content of the first reactor (V ₁ )

5: the volume of the reaction solution in the first reactor (V ₁ ')

6: reactor volume of the second reactor (V ₂ )

7: Content (V ₂ ') of the reaction solution in the second reactor

Summary of the Invention

In the high flow thermoplastic resin of the present invention, in the production of polystyrene by continuously bulk polymerizing a styrene monomer (a raw material solution) in a first reactor and a second reactor, the ratio of the total input flow rate of the styrene monomer is adjusted to It is prepared by separating the second reactor.

In the first reactor, a core reaction for producing polystyrene having an appropriate molecular weight, which is a condition for producing styrene monomer into a high flow resin, is performed. In order to give additional reaction to increase the ratio of the final solid content, an appropriate amount of hydrocarbon compound extracted from petroleum is added in order to give the resin excellent flow characteristics and release property.

The high flow thermoplastic resin according to the present invention is subjected to continuous bulk polymerization while maintaining the styrene monomer input flow rate and reaction time in the first reactor under the conditions of the following formulas (A) to (C); Continuous block polymerization while maintaining the reaction conditions in the second reactor under the conditions of the following formula (D); And by separating the unreacted monomer from the polymer (solids) produced in the second reactor:

F = F ₁ + F ₂ (A)

6.2 ≤ F ₁ / F ₂ ≤ 7.2 (B)

2.4 ≤ V ₁ / V ₁ '≤ 3.0 (C)

2.4 ≤ V ₂ / V ₂ '≤ 4.8 (D)

In the above formula, F is the total flow rate of the styrene monomer to the first, second reactor, F ₁ is the total flow rate of the styrene monomer to the first reactor, F ₂ is the total flow rate of the styrene monomer to the second reactor. Flow rate, V ₁ is the reactor content of the first reactor, V ₁ ′ is the content of the reaction liquid in the first reactor, V ₂ is the reactor content of the second reactor, and V ₂ ′ is the reaction in the second reactor. It is the amount that the amount occupies.

In the production method according to the present invention, the continuous block polymerization is performed at 130 to 140 ° C. in the first reactor, and the continuous block polymerization is performed at 170 to 190 ° C. in the second reactor. The content of polystyrene obtained by the above method is 60 to 75% by weight in the second reactor on a solids basis, the average molecular weight of the final pellet resin is 18 to 250,000, the fluidity is 9.5 to 12.0, the yellowness is 1.0 or less .

Detailed Description of the Invention

Hereinafter, a method of manufacturing the high heat resistant thermoplastic resin of the present invention will be described in more detail.

First, in the first reactor and the second reactor, the styrene monomer is continuously supplied from the tank in which the styrene monomer is stored. Styrene monomers that can be used in the present invention include styrene; side chain alkyl-substituted styrenes such as α-ethylstyrene and α-methylstyrene; Nuclear alkyl substituted styrenes such as vinyl xylene, O-t-butylstyrene, P-t-butylstyrene and P-methyl styrene; Halogenated styrenes such as monochloro styrene, dichloro styrene, tribromo styrene and tetrahydro styrene; P-hydroxy styrene; And O-methoxy styrene. Of these, styrene is most commonly used.

(1) Polymerization in the first reactor

The total flow rate of the raw material solution (styrene monomer) to the first and second reactors is F, the total flow rate of the raw material solution to the first reactor is F ₁ , and the total flow rate of the raw material solution to the second reactor is F _2. When the reactor content of the first reactor is V ₁ , and the content of the reaction solution in the first reactor is V ₁ ′, F = F ₁ + F _2, 6.2 ≤ F ₁ / F ₂ ≤ 7.2, 2.4 ≤ V _Under the condition of ₁ / V ₁ '≤ 3.0, the stirrer rotational speed of the first reactor was adjusted to 30 times / min to continuously bulk polymerize at 130 to 140 ° C.

In the case of F ₁ / F ₂ > 7.2, polystyrene of the appropriate molecular weight cannot be formed, and in the case of F ₁ / F ₂ <6.2, the viscosity of the reactants becomes too high, resulting in poor transport, making it difficult to control the temperature of the second reactor. However, a large amount of low molecular weight polystyrene is generated in the second reactor, so that a desired high flow resin cannot be obtained. In addition, the reason for maintaining the condition of 6.2 ≤ F ₁ / F ₂ ≤ 7.2, F = F ₁ + F _{2 in} the _first reactor is to effectively control the viscosity using the two reactors, to facilitate the transfer of the reactants, It is for making styrene resin of moderate molecular weight excellent in mold release property, and having high fluidity.

In the case of V ₁ / V ₁ '> 3.0, the viscosity becomes too high to increase the load of the stirrer, making it difficult to operate and endangering the lack of time to cope with emergencies. On the other hand, in the case of V ₁ / V ₁ '<2.4, the solid content of the desired content cannot be obtained, and the molecular weight is lowered to obtain the desired resin.

As a result, by maintaining the reaction conditions in the first reactor, it is possible to smoothly transfer the reactants in the continuous bulk polymerization without using a solvent, thereby obtaining a high flow cationic resin having an average molecular weight of 18 to 250,000.

The polymerized product in the first reactor is continuously supplied to the second reactor and subjected to continuous bulk polymerization.

(2) Polymerization in Second Reactor

The total flow rate of the raw material solution (styrene monomer) to the first and second reactors is F, the total flow rate of the raw material solution to the first reactor is F ₁ , and the total flow rate of the raw material solution to the second reactor is F _2. When the content of the reactor in the second reactor is V ₂ , and the content of the reaction solution in the second reactor is V ₂ ′, the conditions of 2.4 ≤ V ₂ / V ₂ '≤ 4.8, F = F ₁ + F ₂ The reactor is fixed at 20 revolutions per minute, and subjected to continuous bulk polymerization at 170 to 190 占 폚 so that the solid content is 65 to 75% by weight. In addition, 2.0 to 2.5% by weight of the hydrocarbon compound is continuously added to the final pellets.

Hydrocarbon compounds usable in the present invention are generally referred to as white oil.

The 2 V in the reactor ₂ / V ₂ For "For a> 4.8, the content of solid matter is reduced drop in _{productivity, V 2 / V 2 '<} 2.4 is turned more low molecular weight generated can not be obtained the specific consent resin, It is difficult to control the polymerization temperature due to the increase in calorific value.

Maintaining the temperature below 170 ° C. in the second reactor results in a decrease in productivity. If the temperature is maintained above 191 ° C., a high molecular weight production rate is low to obtain a desired high flow resin.

Therefore, the reaction conditions of the second reactor are maintained at 2.4 ≤ V ₂ / V ₂ '≤ 4.8, F = F ₁ + F ₂ , 170 to 190 ° C, and 2.0 to 2.5% by weight of the hydrocarbon compound is continuously added. It is possible to obtain a high flow polystyrene with excellent release properties while maintaining productivity.

Other additives, such as molecular weight modifiers, may be added to the first reactor or the second reactor, which can be readily performed by one skilled in the art. For example, an antistatic agent, antioxidant, etc. can be added and used suitably according to each use.

After the polymerization reaction is completed in the second reactor, an unreacted monomer is separated through a temperature riser, a volatilization tank, and the like, and is then cut into pellets. The average molecular weight of the final resin in pellet form was 18 to 250,000, the fluidity was 9.5 to 12.0, and the yellowness was 1.0 or less.

According to the preparation method of the present invention, polystyrene having good transparency and excellent releasability to maintain high flow characteristics is efficiently manufactured using two reactors without additional solvent addition.

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

Example

Example 1

In the first reactor, the polymerization is carried out in which the total flow rate of the raw material solution (styrene monomer) into the first and second reactors is F, the total flow rate of the raw material solution into the first reactor is F ₁ , and the raw material solution is introduced into the second reactor. F = F ₁ + F _2, F ₁ / F ₂ = 6.7 when the total flow rate is F ₂ , the content of the reactor in the first reactor is V ₁ , and the content of the reaction solution in the first reactor is V ₁ ′. , V ₁ / V ₁ '= 2.82 under the reaction conditions. Continuous block polymerization was performed at an agitator speed of 30 times / min and a polymerization temperature of 135 ° C.

The polymer of the first reactor is continuously supplied to the second reactor in the same manner as the supply flow rate of the first reactor, so that the total flow rate of the raw material solution (styrene monomer) into the first and second reactors is F, and the raw material solution is the first reactor. The total flow rate introduced into the reactor F ₁ , the total flow rate of the raw material solution into the second reactor, F ₂ , the reactor volume of the second reactor V ₂ , and the volume of the reaction solution in the second reactor V ₂ ′. At that time, V ₂ / V ₂ ′ = 3.7, F = F ₁ + F ₂ was maintained. The rotation speed of the reactor was fixed at 20 times / minute, and the reaction temperature was maintained at 182 ° C.

In the second reactor, white oil, a hydrocarbon compound extracted from petroleum, was continuously added in a separate storage tank so as to be 2.0% by weight in the final pellet.

The final polymer obtained in the second reactor was continuously sent to a devolatilization step and heated up to 245 ° C. to remove volatile components such as unreacted monomers. Molecular weight, yellowness, and fluidity were measured about the obtained resin on pellets, and mold release property was evaluated using the lattice mold of the injection machine.

Flowability was measured by ASTM D1238 (200 ° C., 5 kg).

Yellowness was measured by JIS K7105.

Molecular weight is 5 mg of the sample in the final pellet, 5 ml of THF is mixed in a shaker and shaken for 30 minutes to completely dissolve the solution, and then the solution is subjected to gel permeation chromatography of SPECTRA-PHYSICS ANALYTICAL. Measured.

The release cracking rate was calculated by converting 20 crack generation rates into a 5.3 OZ injection machine manufactured by Venus Cable using a lattice mold for evaluation of release property.

Example 2

F ₁ / F ₂ = 7.0 and was carried out in the same manner as in Example 1 except that the white oil continuously added to the second reactor was changed to 2.3% by weight.

Example 3

The residence time of the first reactor was adjusted to V ₁ / V ₁ ′ = 2.95, and the same procedure as in Example 1 was carried out except that the white oil continuously added to the second reactor was changed to 2.3 wt%.

Example 4

The same procedure as in Example 1 was conducted except that the residence time of the second reactor was adjusted to V ₂ / V ₂ ′ = 4.3.

Example 5

The same process as in Example 1 was conducted except that the temperature of the second reactor was changed to 188 ° C.

Example 6

The same procedure as in Example 1 was conducted except that the white oil continuously added to the second reactor was changed to 2.5 wt%.

Comparative Example 1

The reaction was carried out in the same manner as in Example 1 except for changing the reactor input ratio of the raw material solution (styrene monomer) to F ₂ = 0.

Comparative Example 2

The same procedure as in Example 1 was carried out except that the residence time of the first reactor was adjusted to V ₁ / V ₁ ′ = 3.25.

Comparative Example 3

The same procedure as in Example 1 was carried out except that the residence time of the second reactor was adjusted to V ₂ / V ₂ ′ = 2.1.

Comparative Example 4

The same process as in Example 1 was conducted except that the temperature of the second reactor was changed to 195 ° C.

Comparative Example 5

The same process as in Example 1 was carried out except that the white oil was changed to 2.9 wt% in the second reactor.

Comparative Example 6

The same procedure as in Example 1 was conducted except that the white oil continuously added to the second reactor was adjusted to 3.5 wt%.

Tables 1 and 2 show the measurement results of the physical properties of the resins prepared according to the examples and the reaction conditions used in Examples 1 to 6 and Comparative Examples 1 to 6, respectively.

Example One 2 3 4 5 6 Reaction condition F ₁ / F ₂ 6.7 7.0 6.7 6.7 6.7 6.7 V ₁ / V ₁ '' 2.82 2.82 2.95 2.82 2.82 2.82 V ₂ / V ₂ '' 3.7 3.7 3.7 4.3 3.7 3.7 Hydrocarbon compound (wt%) 2.0 2.3 2.3 2.0 2.0 2.5 Second reactor temperature (℃) 182 182 182 182 188 182 Properties Average molecular weight (Mw x 1,000) 200 220 190 230 240 200 Yellow Degree (YI) 0.9 0.8 0.9 0.7 0.9 0.9 Fluidity (g / 10 min) 9.9 11.2 12.0 10.0 9.6 10.8 Release Breakage Rate (%) 2.0 1.2 2.1 2.5 1.0 2.3

Comparative Example One 2 3 4 5 6 Reaction condition F ₁ / F ₂ F ₂ = 0 6.7 6.7 6.7 6.7 6.7 V ₁ / V ₁ '' 2.82 3.25 2.82 2.82 2.82 2.82 V ₂ / V ₂ '' 3.7 3.7 2.1 3.7 3.7 3.7 Hydrocarbon compound (wt%) 2.0 2.0 2.0 2.0 2.9 3.5 Second reactor temperature (℃) 182 182 182 195 182 182 Properties Average molecular weight (Mw x 1,000) 150 155 165 160 170 171 Yellow Degree (YI) 1.3 0.9 0.7 1.5 0.9 0.9 Fluidity (g / 10 min) 15.5 15.0 14.6 14.0 13.5 14.5 Release Breakage Rate (%) 10 12 11 13 6 5

From the results of Tables 1 and 2, it can be seen that polystyrene resin having excellent yellowness, mold release property and fluidity can be obtained by continuous bulk polymerization under the reaction conditions according to the present invention.

The present invention has the effect of providing a high-flow thermoplastic resin, which is useful for the production of food and beverage containers, audio product cases, refrigerator internal parts, general merchandise containers, etc., as well as good yellowness and excellent fluidity. .

Simple modifications or changes of the present invention can be easily carried out 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 (4)

The total flow rate of the styrene monomer to the first and second reactors in the first reactor is F, the total flow rate to the first reactor is F ₁ , the total flow rate to the second reactor is F ₂ , and the reactor of the first reactor "when _{called, F = F 1 + F 2} , 6.2 ≤ F 1 / F 2 ≤ 7.2, 2.4 ≤ V 1 / V 1 ' contents information fewer reaction solution points in V _1, a first reactor enemy V ₁ ≤ Continuous block polymerization under the condition of 3.0; When the contents of the reactor of the second reactor in the second reactor is V ₂ , and the contents of the reaction solution in the second reactor are V ₂ ′, 2.4 ≤ V ₂ / V ₂ '≤ 4.8, F = F ₁ + F ₂ Continuous bulk polymerization by continuously adding 2.0 to 2.5% by weight of a hydrocarbon compound on a final pellet basis under the condition of; And Separating the unreacted monomer from the polymer produced from the second reactor and then cutting into pellets; A method for producing a high flow thermoplastic resin having an average molecular weight of 18 to 250,000, characterized by being prepared by the step. The method of manufacturing a high flow thermoplastic resin according to claim 1, wherein the temperature of the first reactor is maintained at 130 to 140 ° C and the temperature of the second reactor is maintained at 170 to 190 ° C. The method of claim 1, wherein the polystyrene solids content in the second reactor is 65 to 75% by weight. The method of producing a high flow thermoplastic resin according to claim 1, wherein the hydrocarbon compound is a white oil.