KR101856565B1 - Method for preparing thermoplastic resin powder having superior flocculation resistance and thermoplastic resin powder prepared therefrom - Google Patents

Abstract

According to an embodiment of the present invention, provided is a method for producing thermoplastic resin powder, comprising the following steps: (a) preparing a latex mixture composed of rubber modified copolymer latex, an adjuvant, and water; and (b) mixing the latex mixture with a latex coagulant to produce latex powder. In the step (b), at least some latex coagulants react with the adjuvant to produce an anti-blocking agent.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a thermoplastic resin powder having excellent cohesion resistance and a thermoplastic resin powder prepared from the thermoplastic resin powder,

The present invention relates to a method for producing a thermoplastic resin powder having excellent cohesion resistance and a thermoplastic resin powder produced therefrom.

Thermoplastic resin powder products whose glass transition temperature is lower than normal temperature have internal diffusion between particles due to the high pressure due to the weight of the product itself when storing or transporting the multi-layered product at a temperature higher than room temperature, Can occur, which is referred to as blocking or caking.

This aggregation phenomenon may cause serious problems in transfer, metering and kneading of the thermoplastic resin powder product. In addition, when the thermoplastic resin powder is extruded or extruded to form a product, the dispersion of the rubber in the matrix may be poor, Or the appearance quality such as coloring property and gloss property may be lowered.

In order to solve such a problem, conventionally, an anti-blocking agent in the form of fine particles such as EBS (ethylene bis stearamide), talc, calcium stearate and the like has been added to a powdered thermoplastic resin And then mixed with the powder to make the thermoplastic resin powder cohesive.

However, when such an antiblocking agent is mixed at the completion of the pulverization, it is difficult to uniformly mix it without the additional blending process. Therefore, the dispersion efficiency of the antiblocking agent is not good, and the amount of the antiblocking agent is increased Not only raises the cost, but also causes deterioration of appearance properties such as physical properties such as impact strength and tensile strength, transparency and gloss of the product.

In addition, since the anti-blocking agent must be added to a separate process through an additional storage tank and an input facility, the process unit price may increase.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the prior art, and it is an object of the present invention to provide an anti-blocking agent which can exhibit excellent cohesiveness even with a small amount of anti- Can be omitted, thereby improving the process efficiency and reducing the unit cost, and a thermoplastic resin powder produced therefrom.

In order to accomplish the above object, one aspect of the present invention provides a method for preparing a rubber latex, comprising: (a) preparing a latex mixture in which a rubber-modified copolymer latex, an adjuvant and water are mixed, and (b) mixing the latex mixture with a latex coagulant, Wherein at least a part of the latex coagulant reacts with the adjuvant in the step (b) to produce an antiblocking agent. The present invention also provides a method for producing a thermoplastic resin powder.

In one embodiment, the adjuvant may include a phosphate based compound.

In one embodiment, the adjuvant is selected from the group consisting of phosphoric acid (H ₃ PO ₄ ), sodium phosphate (Na ₃ PO ₄ ), sodium pyrophosphate (Na ₄ P ₂ O ₇ ) And may include one selected.

In one embodiment, the latex coagulant may comprise a metal salt.

In one embodiment, the latex coagulant is one selected from the group consisting of magnesium sulfate (MgSO ₄ ), magnesium chloride (MgCl ₂ ), calcium sulfate (CaSO ₄ ), calcium chloride (CaCl ₂ ) .

In one embodiment, the reaction of the latex coagulant and the adjuvant may be an ion exchange reaction.

In one embodiment, the anti-blocking agent may be produced at 400 to 600 ppm based on the total weight of the resultant latex powder.

In order to achieve the above object, another aspect of the present invention provides a thermoplastic resin powder comprising an anti-blocking agent produced by the above-described method.

In one embodiment, the weight-based content of the anti-blocking agent may range from 400 to 600 ppm.

In one embodiment, the glass transition temperature may be below 25 占 폚.

According to an aspect of the present invention, it is possible to uniformly mix the anti-blocking agent and the latex powder by simultaneously producing and mixing the anti-blocking agent in the coagulation step of the latex, thereby achieving excellent anti-cohesion property even with a small amount of the anti- And it is possible to omit a separate step of additionally mixing the anti-blocking agent after powdering the latex, thereby improving the process efficiency and reducing the unit cost.

It should be understood that the effects of the present invention are not limited to the effects described above, but include all effects that can be deduced from the description of the invention or the composition of the invention set forth in the claims.

1 is a flow chart of a method for producing a thermoplastic resin powder according to an embodiment of the present invention.
Fig. 2 is a schematic view showing a method of evaluating the coagulation property of the thermoplastic resin powder according to Experimental Example.

Hereinafter, embodiments of the present invention will be described in detail. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements, not excluding other elements unless specifically stated otherwise.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Method for producing thermoplastic resin powder

1 is a flow chart of a method for producing a thermoplastic resin powder according to an embodiment of the present invention.

Referring to FIG. 1, a method for producing a thermoplastic resin powder comprises the steps of (a) preparing a latex mixture in which a rubber-modified copolymer latex, an adjuvant and water are mixed, and (b) mixing a latex mixture and a latex coagulant to form a latex powder . In the step (b), at least a part of the latex coagulant reacts with the auxiliary agent to generate an anti-blocking agent.

Hereinafter, each step of the above-described method for producing a thermoplastic resin powder will be described in detail.

(a) preparing a latex mixture of rubber-modified copolymer latex, adjuvant and water,

The step (a) is a step of preparing an appropriate mixture for agglomeration of the rubber-modified copolymer latex and formation of an anti-blocking agent to be described later, before the rubber-modified copolymer latex is agglomerated and pulverized.

The rubber-modified copolymer latex may be one in which at least one of an aromatic vinyl compound and a vinyl cyan compound is graft-polymerized in an acrylic or conjugated diene rubber latex.

In one embodiment, the aromatic vinyl compound is selected from the group consisting of styrene, alpha methyl styrene, alpha ethyl styrene, vinyl toluene, para bromostyrene, para-chlorostyrene, tert-butyl styrene, dimethyl styrene and mixtures of two or more thereof But may include, but is not limited to, styrene.

In one embodiment, the vinyl cyanide compound may comprise one selected from the group consisting of acrylonitrile, methacrylonitrile, ethacrylonitrile, and mixtures of two or more thereof, preferably comprising acrylonitrile But is not limited thereto.

In one embodiment, the rubber modified copolymer latex may be an acrylonitrile-butadiene-styrene (ABS) latex or an acrylate-styrene-acrylonitrile (ASA) latex , But is not limited thereto.

The adjuvant is a precursor of an anti-blocking agent to be described later, specifically, an inorganic compound capable of reacting with the latex flocculant to generate an anti-blocking agent.

In one embodiment, the adjuvant may comprise a phosphate based compound, and specifically includes phosphoric acid (H ₃ PO ₄ ), sodium phosphate (Na ₃ PO ₄ ), sodium pyrophosphate (Na ₄ P ₂ O ₇ ), and mixtures of two or more thereof.

The latex mixture may be prepared by mixing the rubber-modified copolymer latex and water in a solution and then uniformly stirring the solution.

(b) mixing the latex mixture with a latex coagulant to produce a latex powder wherein at least a portion of the latex coagulant is reacted with the adjuvant Blocking  Generating agent)

In the step (b), a latex coagulant is added to the latex mixture to powder the rubber-modified copolymer latex, and the anti-blocking agent of the thermoplastic resin powder is produced through reaction of the latex coagulant and the auxiliary agent.

Specifically, when the latex coagulant is mixed with the latex mixture, the latex coagulant is a substance (anti-blocking agent) that prevents the thermoplastic resin powder from blocking or caking at least a part of the latex coagulant by causing the coagulation of the rubber- Can be generated.

Thus, by mixing the anti-blocking agent in the latex powder in the process of pulverizing the latex, the anti-blocking agent can be mixed more uniformly than the latex powder is separately mixed after the pulverization process of the latex, It can exhibit excellent cohesion resistance. In addition, since a separate step of additionally mixing the anti-blocking agent after powdering the latex can be omitted, it is possible to improve the process efficiency and reduce the unit cost.

The latex coagulant may be a material that coagulates the rubber-modified copolymer latex as described above and at the same time reacts with the adjuvant to generate an anti-blocking agent. The reaction of the latex flocculant with the adjuvant may be an ion exchange reaction.

In one embodiment, a latex coagulant may comprise a metal salt, specifically, magnesium sulfate (MgSO _4), magnesium chloride (MgCl _2), calcium sulfate (CaSO _4), calcium chloride (CaCl _2), and mixtures of two or more of these And the like.

The latex mixture and the latex coagulant may be mixed in a coagulation bath at 70 to 99 ° C while simultaneously injecting the latex mixture and the latex coagulant, but the method is not limited thereto.

The latex powder can be obtained by dewatering and drying the agglomerated latex mixture. The obtained latex powder may contain an anti-blocking agent produced by the reaction of the latex coagulant and the auxiliary agent in a uniform distribution.

The anti-blocking agent may be produced at 400 to 600 ppm based on the total weight of the resultant latex powder.

When the antiblocking agent is produced in an amount less than 400 ppm, the coagulation effect is insufficient compared with the separately added anti-blocking agent after powdering the latex. If the antiblocking agent is added in an amount exceeding 600 ppm, the coagulability increase rate is insufficient due to an increase in the content of the anti- .

Thermoplastic resin powder

The thermoplastic resin powder according to an embodiment of the present invention can be produced by the method for producing a thermoplastic resin powder as described above.

In particular, the thermoplastic resin powder may contain an anti-blocking agent produced by the reaction of the latex flocculant with the adjuvant in the flocculation step of the latex mixture as described above.

The weight-based content of the antiblocking agent may be 400 to 600 ppm based on the total weight of the thermoplastic resin powder.

When the antiblocking agent is less than 400 ppm, the flocculation effect is weak. When the antiblocking agent is more than 600 ppm, the flocculation increasing rate is insignificant and the efficiency can be lowered.

The glass transition temperature of the thermoplastic resin powder may be room temperature or lower than 25 ° C and thus may have a property that blocking is likely to occur during storage or transportation at a higher temperature than room temperature for a long time, no.

The method for producing the thermoplastic resin powder as described above and the thermoplastic resin powder produced therefrom have a uniform distribution of the antiblocking agent contained therein and can exhibit excellent cohesion resistance even with a small amount of the antiblocking agent so that the content of the antiblocking agent is minimized, And it is possible to omit a separate step of additionally mixing the anti-blocking agent after powdering the latex, thereby improving the efficiency of the process and reducing the unit cost.

Hereinafter, the present invention will be described in detail with reference to examples. It should be noted, however, that the following examples are intended to illustrate the invention and are not to be construed as limiting the scope of the invention in any way.

Example  1 to 6

Sodium pyrophosphate (Na ₄ P ₂ O ₇ ) was added to a solution prepared by mixing acrylonitrile-butadiene-styrene (ABS) latex and water in different amounts for each of Examples 1 to 6 and sufficiently stirred to prepare a latex mixture And the inside of the flocculation tank was stirred at a high speed while simultaneously introducing the latex mixture and magnesium sulfate (MgSO ₄ ) into a flocculation tank at 70 to 99 ° C. The agglomerated latex mixture was dehydrated and dried to obtain a latex powder to prepare a thermoplastic resin powder.

Sodium pyrophosphate was dosed so that the antiblocking agent was produced at 0, 200, 400, 600, 1000 and 2000 ppm in Examples 1 to 6, respectively, based on the total weight of the latex powder.

Comparative Example  1-1 to 1-6

Thermoplastic resin powder was prepared in the same manner as in Examples 1 to 6 except that EBS (Ethylene Bis Stearamide) was added as an anti-blocking agent separately to latex powder instead of sodium pyrophosphate.

Comparative Example  2-1 to 2-6

The thermoplastic resin powder was prepared in the same manner as in Comparative Examples 1-1 to 1-6, except that talc was used instead of EBS in the latex powder.

Comparative Example  3-1 to 3-6

The thermoplastic resin powders were prepared in the same manner as in Comparative Examples 1-1 to 1-6, except that calcium stearate was used instead of EBS in the latex powder.

Experimental Example

FIG. 2 is a schematic view showing a method of evaluating coagulation resistance of the thermoplastic resin powders prepared in Examples 1 to 6 and Comparative Examples 1 to 3.

2, a cylinder of 100 cc is filled with a thermoplastic resin powder, and a weight (A) is measured. A cylinder exactly matching the inner diameter of the cylinder is placed on the cylinder and placed in an oven at 70 ° C Then, a pressure of 1 kg / cm ² was applied to the top of the cylinder for 1 hour. Thereafter, the compressed thermoplastic resin powder was pushed up to 5 mesh, and 100 Hz vibration was transmitted for 100 seconds. Thereafter, the weight (B) of the thermoplastic resin powder mass left on the die was measured, and the caking rate of the thermoplastic resin powder was calculated through the following equation 1, and the calculated results were as shown in Table 1 below .

<Formula 1>

Anti-blocking agent content (ppm) 0 200 400 600 1,000 2,000 Caking rate (%) Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 43 30 10 5 One One Comparative Example 1-1 Comparative Example 1-2 Comparative Example 1-3 Comparative Example 1-4 Comparative Example 1-5 Comparative Example 1-6 43 38 33 25 20 2 Comparative Example 2-1 Comparative Example 2-2 Comparative Example 2-3 Comparative Example 2-4 Comparative Example 2-5 Comparative Example 2-6 43 37 29 18 10 2 Comparative Example 3-1 Comparative Example 3-2 Comparative Example 3-3 Comparative Example 3-4 Comparative Example 3-5 Comparative Example 3-6 43 37 29 18 10 2

In Examples 1 to 6, in which the generation and mixing of the anti-blocking agent were carried out in the coagulation step of the latex, the anti-cohesion was effective when the content of the anti-blocking agent was 400 ppm or more, In Comparative Examples 1 to 3 in which the antifoaming agent is mixed, it is understood that the anti-cohesion property can be exhibited only when the content of the antiblocking agent is at least 1,000 ppm or more.

On the other hand, in Examples 1 to 6, when the content of the antiblocking agent exceeds 600 ppm, the cohesive property increase rate is insignificant and the efficiency of the antiblocking agent is lowered.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

Claims (10)

(a) preparing a latex mixture comprising a rubber modified copolymer latex, a phosphate based compound and water; And
(b) mixing the latex mixture with a metal salt to produce a latex powder and an anti-blocking agent produced by ion-exchange reaction of at least a part of the metal salt with the phosphate compound,
The content of the anti-blocking agent is 400 to 600 ppm based on the total weight of the latex powder,
Wherein the anti-blocking agent is not mixed after the step (b). delete The method according to claim 1,
The phosphate compound may be one selected from the group consisting of phosphoric acid (H ₃ PO ₄ ), sodium phosphate (Na ₃ PO ₄ ), sodium pyrophosphate (Na ₄ P ₂ O ₇ ) By weight based on the total weight of the thermoplastic resin powder. delete The method according to claim 1,
Wherein the metal salt is at least one selected from the group consisting of magnesium sulfate (MgSO ₄ ), magnesium chloride (MgCl ₂ ), calcium sulfate (CaSO ₄ ), calcium chloride (CaCl ₂ ), and a mixture of two or more thereof Way. delete delete A thermoplastic resin powder comprising an antiblocking agent produced by the method of any one of claims 1, 3 and 5. delete 9. The method of claim 8,
Glass transition temperature A thermoplastic resin powder having a temperature of 25 ° C or lower.

Images