KR100193023B1 - Process for production of thermoplastic styrene resins with high impact resistnace and high brilliance properties - Google Patents

Abstract

The present invention is to provide a thermoplastic styrene resin composition having a high impact, high gloss, the thermoplastic styrene resin composition of the present invention (i) polybutadiene rubber containing 10-95% by weight of the sheath content in the first reactor To the styrene-based monomer rubber-like solution having 3-20% by weight dissolved and having a viscosity of 25-150 cps at 25 ° C., 0.011-0.211% by weight of organic peroxide was added as an initiator, and the volume of the reactor in the first reactor was changed to V ₁ ,. when the volume of the reaction mixture that the flow rate per hour that is input from the V _2, the raw material solution in the first reactor F, maintain the condition _{1.8≤V 2 /F≤2.5, 1.5≤V 1 / V} 2 ≤2.5 Continuous bulk polymerization (ii) adding 0.01-0.70% by weight of polydimethylsiloxane to the polymer of the first reactor in the second reactor so that the solid component is 50-85% by weight, and (iii) From the polymer produced in the reactor Obtained by separating the corresponding monomers, characterized in that the ratio of the rubber component to the gel component of the final pellet is in the range of 1.9-3.4 and the average rubber particle size is 0.5-1.5㎛.

Description

Manufacturing method of thermoplastic styrene resin composition having high impact and high gloss

The present invention relates to a thermoplastic resin composition used for molding resin parts such as home appliances and office equipment, and more particularly, by adding an organic peroxide to a styrene-based solution in which polybutadiene rubber is dissolved in a first reactor. High-impact and high-gloss thermoplastics obtained by performing continuous bulk polymerization to complete this process and adding a polydimethylsiloxane to the polymer of the first reactor in the second reactor to carry out the continuous bulk polymerization so that the solid component content is 50-85% by weight. A styrene resin composition and its manufacturing method are related.

In general, molded articles such as home appliances and office equipment should have impact resistance and appearance gloss, so the resin composition used therein should have high impact strength and gloss.

Therefore, the development of a resin composition having the above-described physical properties and low cost is progressing smoothly. The rubber-modified styrene resin composition is being developed as a resin composition for this purpose, and this resin has a higher impact strength and gloss than other resins. It is excellent in terms of workability such as injection molding, extrusion sheet molding, extrusion vacuum molding, etc., and has an advantage of low cost.

In the rubber modified styrene resin, polybutadiene rubber and styrene / butadiene hybrid polymer rubber are generally used, and an important problem to be solved in order to give high impact and high gloss to such rubber modified styrene resin is to control the rubber particle size to the optimum value. Problem and narrowing the particle diameter distribution.

However, when polybutadiene rubber is used, it is very difficult to control the rubber particle size to an optimal value, and when styrene / butadiene hybrid polymer rubber is used, it is easy to control the rubber particle size to an optimum value, but it is difficult to obtain good impact resistance.

Rubber modified styrene resin is a form in which spherical rubber particles are distributed in various sizes on a polystyrene matrix, and the rubber particle size is generally in the range of 1.0-6.0 μm. The particles exhibit the effect of absorbing the impact.

The gloss of the resin molded article is also affected by the size of the rubber particles, the smaller the size of the rubber particles is excellent in gloss, but the smaller the size of the rubber particles in consideration of the glossiness, the lower the impact strength.

US Pat. No. 4,146,589 is a conventional technique for producing a high-impact, high-gloss resin composition, wherein (A) a styrene monomer first solution in which 2-15% by weight of polybutadiene rubber is dissolved has a rubber particle size of about Continuous mass polymerization in the first reactor to 0.5-1.0 μm, and (B) the second styrene monomer solution in which 2-15% by weight of polybutadiene rubber was dissolved in the second reactor so that the rubber particle size was about 2-3 μm. Continuous bulk polymerization (C) mixing the first polymerization solution and the second polymerization solution (D) continuously mixing the mixed solution in a third reactor and (E) heating the solution and (F) removing the solution from the solution. A method for producing a styrene-based rubber modified resin having a rubber phase dispersed by separating a polymer is disclosed.

U. S. Patent No. 4,214, 056 also discloses a method for preparing monoalkenyl aromatic polyblends. US Pat. No. 4,493,922 consists of polystyrene as a matrix and two elastomers or copolymers uniformly dispersed in the matrix, one of which has a particle size of 0.5-0.6 μm and a content of 60-95% by weight of polybutadiene. % And the other disclose a impact resistant thermoplastic molding having a particle size of 2-8 μm and a content of 40-5% by weight relative to polybutadiene.

In addition, Japanese Patent Application Laid-Open No. 57-170950 discloses a rubber comprising (a) a polybutadiene solution (b) methanol and (c) an organopolysiloxane with an average rubber particle size of 0.5-2.5 μm and a rubbery polymer of 1-15% by weight. A modified styrene resin composition is disclosed, and Japanese Patent Application Laid-Open No. 2-34615 discloses a resin composition composed of (a) butadiene rubber polymer (b) toluene and (c) organic polysiloxane.

Among the prior arts of Sykes, the method according to the US patented technologies has the disadvantage that effective impact strength and glossiness cannot be obtained, and the surface appearance of the molded article is not uniform when molded at low temperature. Although dimethylsiloxane is contained, the average rubber particle size, the ratio of the rubber component to the gel component is not constant, and has a disadvantage of not exhibiting good impact properties.

The present inventors have diligently studied to solve the problems of the prior arts, and found that the above problems can be solved by adjusting the ratio of the rubber component to the gel component as well as the average rubber particle size in the resin composition. The invention was completed.

An object of the present invention is to provide a rubber-modified styrene resin composition having high impact and high glossiness, and a method for producing the same.

That is, the resin composition of the present invention (i) 3-20% by weight of the polybutadiene rubber containing 10-95% by weight cis content in the first reactor is dissolved, 5% polybutadiene rubber dissolved at 25 ℃ To the styrene-based monomer rubber-like solution having a viscosity of 25-150 cps, 0.011-0.211% by weight of organic peroxide was added as an initiator, and the volume of the reactor V ₁ , the volume of the reaction solution in the first reactor was V ₂ , When the flow rate of the raw material solution to be fed into the first reactor is F, continuous bulk polymerization is carried out under the conditions of 1.8≤V ₂ /F≤2.5, 1.5≤V ₁ / V ₂ ≤2.5 (ii) In the reactor, 0.01-0.70% by weight of polydimethylsiloxane is added to the polymer of the first reactor to continuously bulk polymerize the solid component to 50-85% by weight, and (iii) the unreacted monomer from the polymer produced in the second reactor. Obtained by separating the The ratio of the non-content range of 1.9 to 3.4, and is characterized in that having an average rubber particle size 0.5-1.5㎛.

Hereinafter, the present invention will be described in detail.

First, in the first reactor, a rubbery solution of styrene monomer in which polybutadiene rubber is dissolved is continuously supplied from a storage tank, and styrene monomer is further supplied. Styrene-based monomers that can be used in the present invention include side-chain alkyl substituted styrenes such as styrene, α-ethylstyrene and α-methylstyrene; Nuclear alkyl substituted styrenes such as vinyltoluene, vinylxylene, o-t-butylstyrene, p-t-butylstyrene and p-methylstyrene; Halogenated styrene 'p-hydroxystyrenes such as monochlorostyrene, dichlorostyrene, tribromostyrene and tetrahydrostyrene; And o-methoxystyrene. Of these, styrene is most commonly used.

As the polybutadiene rubber dissolved in the solution of the styrene monomer, various polybutadiene rubbers can be used, but polybutadiene rubber having a solution polymerization by a lithium catalyst and having a cis form content of 10-95% by weight is preferable. The rubbery solution of styrene monomer in which 5% polybutadiene rubber is dissolved preferably has a viscosity of 25-150 cps at 25 ° C., more preferably 30-145 cps. . The viscosity of the rubbery solution of this styrene monomer is an important factor because it affects the average rubber particle size after the polymerization reaction and the rotation speed of the average shear rate controller during the polymerization reaction.

The concentration of the polybutadiene rubber component dissolved in the rubbery solution of the styrene monomer is preferably in the range of 3-20% by weight relative to the rubbery solution. If the concentration of the polybutadiene rubber component is outside the 3-20% by weight, The styrene-based monomer and the additionally supplied styrene-based monomer in the rubbery solution are not good because they cause phase unevenness, and power loss occurs when supplied into the first reactor. In addition, the required styrene monomer is supplied to the first reactor separately from the rubbery solution, and the amount of the styrene-based monomer is controlled so that the rubber component concentration of the first reactor is 3-10% by weight.

A flow regulator is used to supply the rubbery solution and the styrene monomer to the first reactor at a predetermined ratio, which can be easily carried out by those skilled in the art.

Polymerization in the first reactor is 1.8 ≦ V ₂ / F when the internal volume of the first reactor is V _1, the volume of the reaction solution is V ₂ , and the flow rate per hour at which the raw material solution is introduced into the first reactor is F. The reaction is carried out under the condition of ≤2.5, 1.5≤V ₁ / V ₂ ≤2.5, and the rotation speed of the average shear rate controller of the first reactor should be maintained at 20-40 times / minute. If the value of V ₁ / V ₂ exceeds the above range, the phase inversion is not completed and the rubber particles are unstable and the rubber particles are too small to reduce the impact strength, and the value of V ₁ / V ₂ is less than the above range. In the first reactor, the reason for maintaining 1.5 ≦ V ₁ / V ₂ ≦ 2.5 is to improve the mixing and to control the average rubber particle size.

If V ₂ / F is less than the above range, the molecular weight is too high, there is a problem that the fluidity and processability is lowered, if the above range exceeds the molecular weight is lowered, the problem that impact strength is lowered.

The number of revolutions of the average shear rate regulator of the first reactor shall be maintained at 20-40 revolutions per minute. If the rotation speed of the average shear speed controller is less than 20 times / min, it is difficult to uniformly mix, so there is a risk of runaway reaction, the average rubber particle size increases, and the gloss of resin decreases, and the rotation speed of the average shear speed controller When it exceeds 40 times / min, the load of a regulator increases and it becomes difficult to operate, an average rubber particle size becomes small, and the impact resistance of resin falls.

In addition, in the first reactor, an organic peroxide is used as the reaction initiator. In the present invention, the organic peroxide used in the first reactor affects the ratio of the rubber component to the gel component of the final resin composition. The ratio affects the properties such as high impact and glossiness. In the present invention, the gel component means a portion obtained by graft polymerization of a styrene-based monomer on polybutadiene rubber.

In the present invention, in order for the average rubber particle size of the resin composition to be 0.5-1.5 μm, the ratio of the rubber component to the gel component should be maintained in the range of 1.9-3.4. 0.011-0.211% by weight of organic tube oxide should be added, more preferably 0.013-0.200% by weight of organic peroxide should be added. If the amount of organic peroxide added exceeds 0.211% by weight, The proportion of the component exceeds 3.4, and excellent impact resistance cannot be obtained. As the organic peroxide used in the present invention, ketone peroxides, peroxy ketals, hydroperoxides, peroxy esters, and the like may be used. Preferably, peroxy esters are used.

The polymerized product in the first reactor is continuously supplied to the second reactor, and continuous bulk polymerization is continued. In the second reactor, the continuous bulk polymerization is carried out so that the solid component of the polymerized polymer is 50-85% by weight. The impact strength is lowered when the content of solid component weighted down in the second reactor exceeds 85% by weight.

In the second reactor, polydimethylsiloxane having a viscosity of 10-10,000 cps is added in an amount of 0.01-0.70% by weight based on the total reaction solution in the second reactor, wherein the polydimethylsiloxane is dissolved in a small amount of styrene monomer. do.

Polydimethylsiloxane is located between polystyrene molecules or between polybutadiene rubber particles and polystyrene molecules to buffer shocks to alleviate external impacts within the resin or to be dispersed between polybutadiene rubber components and polystyrene molecules to mitigate impacts. It seems to bring effect. In addition, the polydimethylsiloxane dispersed in the resin is partially bleeded between the polystyrene molecules to cover the resin surface, thereby reducing the stress of the molding when it is released from the mold during injection molding, thereby reducing the physical properties of the residual stress. It is thought to reduce change.

When the viscosity of the polydimethylsiloxane is less than 10 cps, the dispersion effect in the resin is reduced and the impact strength is lowered. When the viscosity of the polydimethylsiloxane exceeds 10,000 cps, a mechanical problem occurs due to the high viscosity when introduced into the second reactor.

In the first reactor or the second reactor, other additives such as chain transfer agents may be added, which can be easily carried out by those skilled in the art. For example, a releasing agent, an antistatic agent, a flow agent, an ultraviolet absorber, an antioxidant, and the like may be appropriately added according to the respective uses.

After the polymerization reaction is completed in the second reactor, an unreacted monomer is separated while passing through an evaporator, a temperature riser, and the like, and is cut into pellets. The final resin composition prepared in the pellet form has a ratio of the rubber component to the gel component in the range of 1.9-3.4 and the average rubber particle size in the range of 0.5-1.5 μm.

The rubber-modified styrene resin composition of the present invention has the effect of the invention having good gloss and impact strength and low manufacturing cost.

Hereinafter, the present invention will be described with reference to Examples and Comparative Examples. The present invention is not limited to these Examples and the like as follows.

Example 1

90 parts by weight of styrene monomer and 10 parts by weight of polybutadiene rubber were added to the polymerization raw material storage tank and dissolved for 3 hours. The viscosity of this rubbery solution was 80 cps. The rubbery solution of the styrene-based monomer and the styrene-based monomer were introduced into the first reactor, and the amount of the styrene-based monomer was controlled by controlling the concentration of the rubber component of the first reactor to maintain 8.0 wt%, as an organic peroxide as an initiator. 0.112 parts by weight of peroxyester was added to 100 parts by weight of the reactant of the first reactor, and polymerization was started at a polymerization temperature of 130 ° C.

In this case, when the volume of the reactor in the first reactor is V ₁ , the volume of the reaction solution is V ₂ , and the flow rate of the raw material solution in the first reactor is F, the rubbery solution and the styrene monomer are as described above. While maintaining the same ratio, the input amount was adjusted to be V ₂ /F=2.1, and the supply flow rate and discharge flow rate were adjusted to maintain V ₁ / V ₂ = 2.0, and the rotational speed of the shear rate controller was 28 times / Minutes.

The polymer of the first reactor was continuously supplied to the second reactor in the same manner as the first reactor feed flow rate, and 0.01 parts by weight of polydimethylsiloxane was added to the second reactor with respect to 100 parts by weight of the total reaction solution. The viscosity of the polydimethylsiloxane was 300 cps, and this polydimethylsiloxane was dissolved in the same amount of styrene monomer and added. IRGX-1076 from Ciba-Geigy Co., Ltd. as an antioxidant, and zinc stearate as a release agent were fed to 1000 ppm and 8000 ppm, respectively, in the final pellet. The solid component content of the polymer obtained in the second reactor was 80% by weight.

The final polymerization solution was sent to a devolatilization step and heated up to 240 ° C. to remove volatile components such as unreacted monomers and prepared in pellet form. Then, the average rubber particle size of the pelletized resin composition and the ratio of the rubber component to the gel component were measured. Glossiness, Izod impact strength and tensile strength were measured and the results are shown in Table 1 below.

Example 2

The viscosity of the rubbery solution was 130 cps, and the same procedure as in Example 1 was conducted except that the rotation speed of the shear rate controller of the first reactor was 40 / min. The results are shown in Table 1 below.

Example 3

The same procedure as in Example 1 was conducted except that the volume (V ₁ / V ₂ ) of the reactor volume / reaction liquid in the first reactor was adjusted to 2.3 by adjusting the retention period. The results are shown in the following table. 1 is shown.

Example 4

The same procedure as in Example 1 was conducted except that the rotation speed of the shear rate controller of the first reactor was 26 times / minute, and the results are shown in Table 1 below.

Example 5

Except that 0.150 parts by weight of peroxy ester in the first reactor was carried out in the same manner as in Example 1, the results are shown in Table 1 below.

Example 6

Except for adding 0.179 parts by weight of peroxy ester in the first reaction tank was carried out in the same manner as in Example 1, the results are shown in Table 1 below.

Example 7

The same procedure as in Example 1 was conducted except that the solid component content in the second reactor was adjusted to 60 wt% by adjusting the residence time, and the results are shown in Table 1 below.

Example 8

The same procedure as in Example 1 was carried out except that the solid component content in the second reactor was adjusted to 85 wt% by adjusting the residence time, and the results are shown in Table 1 below.

Example 9

Except that 0.3 parts by weight of polydimethylsiloxane was carried out in the same manner as in Example 1, the results are shown in Table 1 below.

Example 10

Except that 0.6 parts by weight of polydimethylsiloxane was carried out in the same manner as in Example 1, the results are shown in Table 1 below.

Example 11

Except that the viscosity of the polydimethylsiloxane is 1000cps was carried out in the same manner as in Example 1, the results are shown in Table 1 below.

Example 12

Except that the viscosity of the polydimethylsiloxane was 8000cps was carried out in the same manner as in Example 1, the results are shown in Table 1 below.

Comparative Example 1

Except that the viscosity of the rubber solution is 200cps and the rotation speed of the shear rate controller in the first reactor was 38 times / minute was carried out in the same manner as in Example 1, the results are shown in Table II.

Comparative Example 2

The same procedure as in Example 1 was conducted except that the volume (V ₁ / V ₂ ) of the reactor volume / reaction liquid in the first reactor was adjusted by adjusting the residence time, and the results are shown in Table II. Shown in

Comparative Example 3

Except that 0.313 parts by weight of peroxy ester in the first reactor was carried out in the same manner as in Example 1, the results are shown in Table 2 below.

[Comparative Example 4]

Except that 0.413 parts by weight of peroxy ester in the first reactor was carried out in the same manner as in Example 1, the results are shown in Table 2 below.

[Comparative Example 5]

The same procedure as in Example 1 was conducted except that the solid component content was 90 wt% in the second reactor by adjusting the residence time. The results are shown in Table 2 below.

Comparative Example 6

Except that 0.005 parts by weight of polydimethylsiloxane was carried out in the same manner as in Example 1, the results are shown in Table 2 below.

Comparative Example 7

Except that the viscosity of the polydimethylsiloxane is 15,000cps was carried out in the same manner as in Example 1, the results are shown in Table 2 below.

Comparative Example 8

The same procedure as in Example 1 was conducted except that the volume (V ₁ / V ₂ ) of the reactor volume / reaction liquid in the first reactor was adjusted to 2.9 by adjusting the residence time. Shown in

Physical properties shown in Tables 1 and 2 were measured by the following method.

(1) Gloss: It measured according to JIS K 7156 (60 °).

(2) Idose impact strength was measured according to ASTM D256. (1.8 notched)

(3) Tensile strength: measured according to ASTM D 638. (Speed: 20 mm / min).

(4) Average rubber particle size: 0.3 g of the sample was dissolved in 10 ml of a solvent (DMF), and then measured by an English Malburton machine.

(5) Gel content: 1 g of sample was accurately weighed and recorded in a Erlenmeyer flask (1), and it was dissolved in 20 ml MEK. The dissolved sample was transferred to an accurately weighed SUS tube (②), and 20 ml of MEK was added to an Erlenmeyer flask to transfer the remaining sample to reduce an analysis error. After separating with a centrifuge (condition: at least 15,000rpm at ± 50 ℃, 30 minutes or more), the supernatant was discarded and 10ml MEK was added to the precipitate and pulverized with a grinder. 30 ml of MEK was added and centrifuged. The supernatant was discarded and dried in a 105 ° C. convection oven for 4 hours, allowed to cool for 20 minutes in a desiccator, and weighed SUS tube after the cooling was completed. Gel content was calculated by the following equation.

Gel content (%) = [(③-②) ÷] × 100

(6) Rubber content: 0.4 g of the sample was placed in a 50 ml volumetric flask and weighed. For blank experiments, 30 ml of chloroform was added to the extra flask to dissolve the sample, and then 10 ml of ICI-CCI mixture was added and chloroform was added to make 50 ml. After leaving for 30 minutes, 20 ml of the flask was collected and mixed with about 60 ml of KI solution. After dropping 3-4 drops of starch, the titration was performed by titration with 0.04N NaSO, and the rubber component content was measured by the following formula.

f: Correction value for normal concentration of Na ₂ S ₂ O ₃ .

Claims (5)

In preparing a high impact, high gloss thermoplastic styrene resin composition, (i) when the solution is dissolved at 5% concentration in a styrene monomer in the first reactor, the viscosity of the solution is 25-150 cps polybutadiene rubber 3-20 at 25 ° C. The styrene-based monomer is added to the rubbery solution of the styrene-based monomer dissolved in the weight%, and the amount of the styrene-based monomer is controlled to maintain the concentration of the rubber component of the first reactor 3-10% by weight, and the organic peroxide as an initiator is added. The amount per hour of the reactor is added in the amount of 0.011-0.211% by weight relative to the reactants in the first reactor, the volume of the reactor in the first reactor V ₁ , the volume of the reaction solution V ₂ , and the raw material solution in the first reactor When F is set to a continuous bulk polymerization so that the conditions are 1.8≤V ₂ /F≤2.5, 1.5≤V ₁ / V ₂ ≤2.5 and (ii) the polydimethylsiloxane is added to the polymer of the first reactor in the second reactor. By adding siloxane, the solid content is 50- Continuous mass polymerization to reach 85% by weight and (iii) separating the unreacted monomer from the polymer produced in the second reactor, characterized in that the method for producing a thermoplastic styrene resin composition. The method for producing a thermoplastic styrene resin composition according to claim 1, wherein the content of polybutadiene rubber in the used rubbery solution is 3-20% by weight. The method for producing a thermoplastic styrene resin composition according to claim 1, wherein the organic peroxide is selected from the group consisting of ketone peroxides, peroxy ketals, high peroxides, and peroxy esters. The method of claim 1, wherein the polydimethylsiloxane has a viscosity of 10-10,000 cps and is introduced in an amount of 0.01-0.70% by weight based on the reactants of the second reactor. The method for producing a thermoplastic styrene resin composition according to claim 1, wherein the first reactor is operated by a shear rate controller having a speed of 20-40 times / minute.