KR101988293B1 - A method for preparing rubber polymer latex - Google Patents

Abstract

Provided by the present invention is a rubber polymer latex producing method which includes: a step (a) of producing a polymer seed by polymerizing 5 to 15 parts by weight of an aromatic vinyl monomer, 0.2 to 1.0 parts by weight of a polymerization initiator, and 0.01 to 0.2 parts by weight of a first emulsifier; a step (b) of polymerizing 85 to 95 parts by weight of the conjugated diene monomer and the polymer seed in the presence of 0.1 to 1.0 parts by weight of a molecular weight modifier, 0.1 to 1.0 part by weight of an electrolyte, and 1.5 to 2.5 parts by weight of a second emulsifier so that the conversion ratio of the conjugated diene monomer is 65 to 85%; and a step (c) of making the product of the step (b) react so that the conversion ratio of the conjugated diene monomer is 90% or more in the presence of 0.1 to 1.0 parts by weight of a third emulsifier and thereby producing polymer latex. The rubber polymer latex produced by the present invention has high productivity and excellent appearance quality.

Description

TECHNICAL FIELD [0001] The present invention relates to a rubber latex polymer latex,

The present invention relates to a method for producing a rubbery polymer latex which improves the appearance when applied to a resin by increasing the total refractive index of the rubber.

ABS (acrylonitrile-butadiene-styrene) resin is excellent in mechanical properties, colorability, and moldability, and is widely used for housings, toys, office equipment, automobiles, and the like of various electronic products including home appliances such as refrigerators and washing machines.

The conjugated diene rubber polymer latex has a low glass transition temperature (Tg) and therefore has excellent rubber properties and is widely used for improving the impact strength of ABS resin. Particularly, the fracture behavior can be changed depending on the particle diameter and the dispersibility of the rubbery polymer latex contained in the ABS resin. Thus, a rubbery polymer latex is usually produced by an emulsion polymerization method having advantageous grain size control.

Specifically, in order to impart impact resistance in the production of ABS resin, a large-volume rubbery polymer latex having an average particle diameter of 3,000 Å is used, which is prepared by enlarging a rubbery polymer latex having a particle size of 1,500 Å or less or by emulsion polymerization Can be manufactured.

Of these, the rubbery polymer latex having a large particle diameter of 3,000 ANGSTROM or more, which is directly produced through emulsion polymerization, has a narrow particle size distribution and a low gel content, which is advantageous in impact resistance. However, a polymerization time of 30 hours or more is required. The time is prolonged and the polymerization conversion rate tends to decrease.

On the other hand, when a rubbery polymer latex having a particle size of less than 1,500 Å is enlarged to produce a rubbery polymer latex having a particle size of 3,000 Å or more, particle size control is relatively easy and a wide particle size distribution is exhibited. The presence of small particle size particles in a wide particle size distribution is advantageous for improving the surface gloss and sharpness of the ABS resin.

In addition, it takes a relatively short reaction time of usually 15 to 20 hours, which is advantageous from the viewpoint of productivity. However, there is a problem that the polymerization stability is lowered due to an increase in viscosity due to small particle diameters. In addition, There is a limit.

In order to solve this problem, there have been proposed a method in which the reaction time is shortened by using a high temperature in order to increase the productivity of the rubbery polymer having a small particle size, a method in which the conjugated diene monomer is divided or continuously injected to increase the volume ratio of the reaction tank, And a method of accelerating the initial particle generation rate according to polymerization has been proposed.

However, when the reaction time is shortened by using the high temperature, it is necessary to use an expensive refrigerant for the control of the reaction heat and to increase the gel content due to the excessive production of 1,2-butadiene isomer, which is advantageous for crosslinking at high temperature, There is a problem that the impact resistance is lowered.

In addition, the method of preparing a conjugated diene monomer by dividing or continuously injecting the monomer causes a delay in the polymerization time with the decrease of the reaction rate, and the low temperature polymerization method using the redox initiator and the oxidizing / reducing agent causes a low reaction rate of the conjugated diene monomer There is a limitation in shortening the particle generation rate, and there is a problem that the polymerization stability of the water-soluble initiator is lowered and the thermal stability of the ABS resin as the final product is lowered due to by-products such as an oxidizing agent and a reducing agent.

Therefore, there is a continuing need for research on rubbery polymer latexes having not only excellent mechanical strength but also excellent appearance properties.

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a method for producing a rubbery polymer latex which shortens the reactivity to improve productivity,

In one aspect of the present invention, there is provided a process for producing a polymer composition, comprising: (a) polymerizing 5 to 15 parts by weight of an aromatic vinyl monomer, 0.2 to 1.0 part by weight of a polymerization initiator, and 0.01 to 0.2 part by weight of a first emulsifier to prepare a polymer seed; (b) 85 to 95 parts by weight of the polymer seed and the conjugated diene monomer in the presence of 0.1 to 1.0 part by weight of the molecular weight modifier, 0.1 to 1.0 part by weight of the electrolyte and 1.5 to 2.5 parts by weight of the second emulsifier, %; And (c) reacting the product of the step (b) with the conjugated diene monomer in the presence of 0.1 to 1.0 part by weight of the third emulsifier so that the conversion ratio of the conjugated diene monomer is 90% or more. Of the present invention.

In one embodiment, the aromatic vinyl monomer may be selected from the group consisting of styrene, alpha methyl styrene, alpha ethyl styrene, paramethyl styrene, and mixtures of two or more thereof.

In one embodiment, the polymerization initiator may be a persulfate-based initiator.

In one embodiment, the persulfate-based initiator may be selected from the group consisting of sodium persulfate, potassium persulfate, ammonium persulfate, and mixtures of two or more thereof.

In one embodiment, the first, second and third emulsifiers are selected from the group consisting of fatty acid soaps, alkali salts of rosin acid, alkylaryl sulfonates, alkaline methyl alkyl sulfates, sulfonated alkyl esters, and mixtures of two or more thereof ≪ / RTI >

In one embodiment, the molecular weight modifier may be selected from the group consisting of tert-butyl mercaptan, tert-dodecyl mercaptan, methyl mercaptan, and mixtures of two or more thereof.

In one embodiment, the electrolyte is selected from the group consisting of Na ₂ SO ₄ , K ₂ SO ₄ , KCl, NaCl, KHCO ₃ , NaHCO ₃ , K ₂ CO ₃ , Na ₂ CO ₃ , KHSO ₃ , NaHSO ₃ , K ₄ P ₂ O ₇ , K ₃ PO ₄ , Na ₃ PO ₄ , Na ₂ HPO _4, and mixtures of two or more thereof.

In one embodiment, the conjugated diene monomer is selected from the group consisting of 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, piperylene, 3-butyl- , 3-butadiene, and mixtures of two or more thereof.

In one embodiment, the relationship between Ta, Tb and Tc and Ta < Tb < Tc can be satisfied in the steps (a) to (c).

In one embodiment, the Ta may be between 45 and 55 &lt; 0 &gt; C.

In one embodiment, the Tb may be 60-70 &lt; 0 &gt; C.

In one embodiment, the Tc may be 70-80 &lt; 0 &gt; C.

In one embodiment, the average particle size of the polymer seed may be between 2,000 and 2,500 Angstroms.

In one embodiment, the average particle size of the polymer latex may range from 2,700 to 3,300 A.

In one embodiment, the gel content of the polymer latex can be 75-90%.

The method of producing a rubbery polymer latex according to one aspect of the present invention includes a step of preparing a polymer seed from which the entire polymerization reaction time can be shortened and the particle size of the rubbery polymer latex can be precisely controlled.

In addition, when the rubber polymer latex having an increased total refractive index of rubber is applied to an ABS resin, the impact strength can be maintained at a similar level, but the coloring property and appearance characteristics can be improved.

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.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to the accompanying drawings. 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 a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "indirectly connected" . Also, 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.

According to an aspect of the present invention, there is provided a process for producing a polymer composition, comprising: (a) polymerizing 5 to 15 parts by weight of an aromatic vinyl monomer, 0.2 to 1.0 part by weight of a polymerization initiator, and 0.01 to 0.2 part by weight of a first emulsifier to prepare a polymer seed; (b) 85 to 95 parts by weight of the polymer seed and the conjugated diene monomer in the presence of 0.1 to 1.0 part by weight of the molecular weight modifier, 0.1 to 1.0 part by weight of the electrolyte and 1.5 to 2.5 parts by weight of the second emulsifier, %; And (c) the conversion of the conjugated diene monomer is 90% or more, preferably 90 to 98%, more preferably 90 to 95% in the presence of 0.1 to 1.0 part by weight of the third emulsifier. And reacting the product to prepare a polymer latex. The present invention also provides a method for producing a rubbery polymer latex.

The step (a) is a step of preparing a polymeric seed to shorten the reaction time in the production of the rubbery polymer latex. The presence of the polymeric seed may increase the rate of polymerization proceeding in the subsequent step, The reaction time can be shortened and the productivity can be improved. In addition, the particle size distribution of the rubbery polymer latex as the final product can be controlled, and the impact resistance can be improved when blended with the ABS resin.

The aromatic vinyl monomer may be selected from the group consisting of styrene, alpha methyl styrene, alpha ethyl styrene, paramethyl styrene, and mixtures of two or more thereof, preferably styrene, but is not limited thereto.

The aromatic vinyl monomer may be included in an amount of 5 to 15 parts by weight. If the content of the aromatic vinyl monomer is less than 5 parts by weight, the number of molecules may be too small to increase the productivity due to the improvement in the polymerization reaction rate. If the content of the aromatic vinyl monomer is more than 15 parts by weight, the coloring property may be improved. Tg) is increased and the impact resistance may be lowered.

The polymerization initiator may be a persulfate-based initiator and the persulfate-based initiator may be selected from the group consisting of sodium persulfate, potassium persulfate, ammonium persulfate, and mixtures of two or more thereof, but is not limited thereto .

The polymerization initiator may be included in an amount of 0.2 to 1.0 part by weight. If the amount of the polymerization initiator is less than 0.2 parts by weight, the polymerization rate may be lowered and the productivity may be lowered. If the amount is more than 1.0 part by weight, the average particle diameter of the polymer seed may decrease.

Wherein the first, second and third emulsifiers are each selected from the group consisting of fatty acid soaps, alkali salts of rosin acid, alkylaryl sulfonates, alkaline methyl alkyl sulfates, sulfonated alkyl esters, and mixtures of two or more thereof But is not limited thereto.

The first emulsifier may be included in an amount of 0.01 to 0.2 part by weight. If the amount of the first emulsifier is less than 0.01 part by weight, the polymerization reaction may not occur. If the amount of the first emulsifier is more than 0.2 parts by weight, the average particle diameter of the polymer seed may be less than 2000 Å, and the mechanical properties of the rubber polymer latex as a subsequent product may be deteriorated.

The molecular weight modifier may be selected from the group consisting of tert-butyl mercaptan, tert-dodecyl mercaptan, methyl mercaptan, and mixtures of two or more thereof, preferably tert-dodecyl mercaptan, But is not limited thereto.

The molecular weight adjuster may be included in an amount of 0.1 to 1.0 part by weight. If the molecular weight regulator is less than 0.1 part by weight, the gel content of the rubbery polymer latex may be excessively increased, and if the molecular weight regulator is more than 1.0 part by weight, the gel content may be significantly decreased and the mechanical properties of the ABS resin may be deteriorated .

The electrolyte is a _{Na 2 SO 4, K 2 SO} 4, KCl, NaCl, KHCO 3, NaHCO 3, K 2 CO 3, Na 2 CO 3, KHSO 3, NaHSO 3, K 4 P 2 O 7, K 3 PO 4 , Na ₃ PO ₄ , Na ₂ HPO ₄ and mixtures of two or more thereof, preferably Na ₂ SO ₄ , K ₂ SO ₄ , KCl NaCl and mixtures of two or more thereof , But is not limited thereto.

The electrolyte may be contained in an amount of 0.1 to 1.0 part by weight. If the amount of the electrolyte is less than 0.1 part by weight, the average particle diameter of the polymer latex may be decreased and the viscosity of the ABS resin may increase. If the amount of the electrolyte is more than 1.0 part by weight, the polymerization stability may remarkably decrease.

The kind of the second emulsifier is the same as that described above for the first emulsifier, and may be included in an amount of 1.5 to 2.5 parts by weight. If the amount of the second emulsifier is less than 1.5 parts by weight, polymerization stability may be deteriorated. If the amount of the second emulsifier is more than 2.5 parts by weight, new particles may be formed during the polymerization reaction, which may make it difficult to control the average particle diameter of the polymer latex.

Wherein the conjugated diene monomer is at least one selected from the group consisting of 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, piperylene, 3 -butyl-1,3-octadiene, isoprene, And a mixture of two or more of them. Preferably, it may be 1,3-butadiene or 2,3-dimethyl-1,3-butadiene, but is not limited thereto.

The aromatic vinyl monomer may have a refractive index higher than that of the conjugated diene monomer. The refractive index of the aromatic vinyl monomer is 1.5 or more, and the refractive index of the conjugated diene monomer is 1.4 or more. The polymer latex polymerized by using a polymer seed having a high refractive index can improve the coloring property in the production of ABS resin.

The step (b) is a step of polymerizing the conjugated diene monomer so that the conversion of the conjugated diene monomer is 65 to 85% in the presence of the molecular weight modifier, the electrolyte and the second emulsifier. In the section where the polymerization conversion rate of the conjugated diene monomer is 65 to 85%, the polymerization reaction speed is high, so that excessive reaction heat is generated, and the viscosity may greatly increase, which may correspond to a period in which the polymerization stability may deteriorate. Therefore, by controlling the third emulsifier in the step (c), the reaction heat can be controlled and polymerization stability can be secured at the same time.

The kind of the third emulsifier is the same as that described above with respect to the kind of the first emulsifier, and may be included in the range of 0.1 to 1.0 part by weight. If the amount of the third emulsifier is less than 0.1 parts by weight, the polymerization stability may deteriorate and the amount of the coagulated material may increase. When the amount of the third emulsifier is more than 1.0 parts by weight, May occur.

Wherein Ta, Tb and Tc are in the range of 45 to 55 占 폚, 60 to 70 占 폚 and 70 to 80 占 폚, respectively, and Ta <Tb <Tc The relationship can be satisfied.

In the step (a), the temperature Ta may be maintained at 45 to 55 캜 through a heat exchanger. If the Ta is less than 45 ° C, the reaction time may be long due to the low temperature. If the Ta is more than 55 ° C, the average particle diameter of the polymer seed may become larger than necessary due to excessive reaction.

In the step (b), the temperature (Tb) may be maintained at 60 to 70 ° C through a heat exchanger. If the Tb is less than 60 ° C, the polymerization reaction of the polymer seed and the conjugated diene monomer is difficult to start within a relatively short period of time (10 to 60 minutes) due to a low reaction temperature. If the Tb is more than 70 ° C, Can be difficult to control.

In the step (c), the temperature Tc may be maintained at 70 to 80 캜 through a heat exchanger. If the Tc is less than 70 캜, the polymerization reaction between the polymer seed and the conjugated diene monomer is difficult to continue due to a low reaction temperature, and if the T c is higher than 80 캜, it may be difficult to control the process due to excessive reaction heat.

The polymer seed may have an average particle diameter of 2,000 to 2,500 angstroms. If the average particle diameter of the polymer seed is less than 2,000 ANGSTROM, the average particle diameter of the rubbery polymer latex may be less than 2,700 ANGSTROM and the impact resistance may be deteriorated when applied to the final ABS resin. If the average particle diameter is more than 2,500 ANGSTROM, When the polymer seed is further added in order not to lower the reaction rate, the mechanical properties and impact resistance of the ABS resin may be lowered.

The polymer latex may have an average particle diameter of 2,700 to 3,300 Å. If the average particle diameter of the polymer latex is less than 2,700 ANGSTROM, the mechanical properties of the ABS resin may be deteriorated. If the average particle diameter of the polymer latex is more than 3,300 ANGSTROM, .

The gel content of the polymer latex may be 75-90%. If the gel content is less than 75% or more than 90%, the mechanical properties of the ABS resin, particularly impact resistance, may be reduced.

Hereinafter, embodiments of the present invention will be described in detail.

Example 1

(1) Preparation of polymer seed

100 parts by weight of ion-exchanged water, 10 parts by weight of styrene (SM) as an aromatic vinyl monomer, 0.5 parts by weight of potassium persulfate (K ₂ S ₂ O ₈ ) as a polymerization initiator, 0.5 part by weight of rosin acid alkali And 0.1 part by weight of a salt were administered in a batch, followed by reaction at 50 DEG C for 2 hours to prepare a polymer seed.

(2) Production of rubbery polymer latex

90 parts by weight of 1,3-butadiene (BD), 0.5 part by weight of tert-dodecyl mercaptan as a molecular weight modifier, 0.5 part by weight of sodium sulfate (Na ₂ SO ₄ ) as an electrolyte, 2 as an emulsifier and 2.0 parts by weight of an alkali salt of rosin as starting materials were reacted at a temperature of 70 캜 until the polymerization conversion rate of 1,3-butadiene reached 75%.

Thereafter, 10 parts by weight of ion-exchanged water and 0.5 part by weight of an alkali salt of rosin as a third emulsifier were added, and the reaction temperature was gradually raised to 80 DEG C, and the reaction was terminated at a polymerization conversion rate of 92% to obtain a rubbery polymer latex Respectively.

Example 2

(1) Preparation of polymer seed

100 parts by weight of ion-exchanged water, 15 parts by weight of styrene as an aromatic vinyl monomer, 1.0 part by weight of potassium persulfate (K ₂ S ₂ O ₈ ) as a polymerization initiator, 0.02 parts by weight of a rosin acid alkali salt as a first emulsifier And the mixture was reacted at 50 DEG C for 2 hours to prepare a polymer seed.

(2) Production of rubbery polymer latex

85 parts by weight of 1,3-butadiene, 0.5 part by weight of tert-dodecyl mercaptan as a molecular weight modifier, 0.5 part by weight of sodium sulfate (Na ₂ SO ₄ ) as an electrolyte, and 0.5 part by weight of a second emulsifier And 2.5 parts by weight of an alkali salt of rosin were added to the mixture at a temperature of 70 캜 until the conversion of 1,3-butadiene was 85%.

Thereafter, 10 parts by weight of ion-exchanged water and 0.1 part by weight of an alkali salt of rosin as a third emulsifier were added, and the reaction temperature was gradually raised to 80 DEG C, and the reaction was terminated at a polymerization conversion rate of 92% to obtain a rubbery polymer latex Respectively.

Example 3

(1) Preparation of polymer seed

100 parts by weight of ion-exchanged water, 5 parts by weight of styrene as an aromatic vinyl monomer, 0.2 parts by weight of potassium persulfate (K ₂ S ₂ O ₈ ) as a polymerization initiator, 0.2 parts by weight of a rosin acid alkali salt as a first emulsifier And the mixture was reacted at 50 DEG C for 2 hours to prepare a polymer seed.

(2) Production of rubbery polymer latex

95 parts by weight of 1,3-butadiene, 0.5 part by weight of tert-dodecylmercaptan as a molecular weight modifier, 0.5 part by weight of sodium sulfate (Na ₂ SO ₄ ) as an electrolyte, and 0.5 part by weight of a second emulsifier And 1.5 parts by weight of an alkali salt of rosin were added to the reaction mixture at a temperature of 70 캜 until the polymerization conversion of 1,3-butadiene reached 65%.

Thereafter, 10 parts by weight of ion-exchanged water and 1.0 part by weight of an alkali salt of rosin as a third emulsifier were added, and the reaction temperature was gradually raised to 80 DEG C, and the reaction was terminated at a polymerization conversion rate of 92% to obtain a rubbery polymer latex Respectively.

Comparative Example 1

Except that (1) 100 parts by weight of 1,3-butadiene and ( ₂ ) 0.5 parts by weight of potassium persulfate (K ₂ S ₂ O ₈ ) as a polymerization initiator were collectively administered in the preparation of the rubbery polymer latex, , A rubbery polymer latex was obtained in the same manner as in Example 1 above.

Comparative Example 2

(1) Preparation of polymer seed

A polymer seed was prepared in the same manner as in Example 1 except that 20 parts by weight of styrene was used as an aromatic vinyl monomer.

(2) Production of rubbery polymer latex

A rubbery polymer latex was obtained in the same manner as in Example 1 except that 80 parts by weight of 1,3-butadiene was used as a conjugated diene monomer.

Comparative Example 3

(1) A rubbery polymer latex was obtained in the same manner as in Example 1, except that 10 parts by weight of methyl-methacrylate (MMA) as an aromatic vinyl monomer was collectively administered in the preparation of the polymer seed to prepare a polymer seed.

Comparative Example 4

(2) Rubber Polymer A polymeric seed was prepared in the same manner as in Example 1 except that 3.0 parts by weight of a rosin acid alkali salt was added as a second emulsifier in the preparation of the latex and the third emulsifier was not added, to obtain a rubbery polymer Respectively.

Comparative Example 5

(1) A polymer seed was prepared in the same manner as in Example 1, except that 0.1 part by weight of potassium persulfate as a polymerization initiator and 0.01 part by weight of an alkali salt of rosin as a first emulsifier were used as a polymerization initiator in the preparation of a polymer seed, .

The dose, the average particle diameter, the reaction time, the gel content, and the solid content of the polymer seed and the rubbery polymer latex according to Examples 1 to 3 and Comparative Examples 1 to 5 are shown in Table 1 below. Units of the dose of each component are parts by weight unless otherwise specified.

The rubbery polymer latex was solidified by using a 1% sulfuric acid solution, washed and dried in a vacuum oven at 50 DEG C for 24 hours. Then, 1 g of the obtained solidified product was placed in 100 g of toluene and stored in a dark room at room temperature for 48 hours. And gel, and the gel content of the rubbery polymer latex was calculated according to the following formula (1).

[Equation 1]

Gel content (%) = [(weight of insoluble matter (gel)) / (weight of sample)] * 100

Further, the average particle size of the rubbery polymer latex was measured using Nanotrac 150 by dynamic laser light scattering method.

step division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 (One) SM 10 15 5 - 20 - 10 10 (One) MMA - - - - - 10 - - (One) Polymerization initiator 0.5 1.0 0.2 - 0.5 0.5 0.5 0.1 (One) The first emulsifier 0.1 0.02 0.2 - 0.1 0.1 0.1 0.01 (One) Average particle diameter
(A) 2,200 2,450 2,020 - 2,380 2,040 2,200 2,850 (2) BD 90 85 95 100 80 90 90 90 (2) The second emulsifier 2.0 2.5 1.5 2.0 2.0 2.0 3.0 2.0 (2) The third emulsifier 0.5 0.1 1.0 0.5 0.5 0.5 0 0.5 (2) Gel content (%) 82 78 86 87 77 83 87 76 (2) Average particle diameter
(A) 2,950 3,250 2,750 3,050 2,880 2,820 2,490 3,680 (2) Coagulation product (%) 0.005 0.003 0.005 0.01 0.005 0.008 0.03 0.03 (2) Reaction time (hr) 20 21 21 32 17 20 19 27

As shown in Table 1, the rubbery polymer latexes of Examples 1 to 3 prepared according to the present invention had excellent productivity in a short reaction time as compared with Comparative Examples 1 to 5, and significantly decreased the solidification content, Can be improved. In contrast to the Comparative Examples 2, 4 and 5 in which the dosage of the emulsifier, the polymerization initiator or the conjugated diene monomer deviates from the range of the present invention, the solid content of the rubbery polymer latex is decreased, Can be produced. Compared with Comparative Example 3 using a methyl-methacrylate having a lower refractive index than 1,3-butadiene, which is a conjugated diene monomer, as an aromatic vinyl monomer, it can be confirmed that the solidified water content is decreased.

It can be seen that the rubbery polymer latexes of Examples 1 to 3 are easier to control the particle diameter when the rubbery polymer latex is produced in view of the narrower particle diameter distribution than the rubbery polymer latexes of Comparative Examples 1 to 5.

The graft copolymer latex prepared according to the methods of Examples 1 to 3 and Comparative Examples 1 to 5 was prepared by the method disclosed in Korean Patent No. 10-1094181, and each graft copolymer latex 30 , 70 parts by weight of a SAN resin having a weight average molecular weight (Mw) of 100,000 and an acrylonitrile content of 25%, 0.75 part by weight of a lubricant and 0.25 part by weight of a heat stabilizer were mixed and extruded, To prepare 15 wt% of each thermoplastic resin specimen.

The impact strength, surface gloss, colorability (L) and injection stability of the thermosetting resin were measured by the following methods. The results are shown in Table 2 below.

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Izod impact strength
(1/4 ", Kg · cm / cm) 25 24 25 26 18 21 19 27 Surface gloss (60 °) 96 97 97 93. 97 96 97 91 Colorability (L) 25.3 25.0 25.4 27.5 25.0 27.2 25.0 25.8 Injection stay thermal stability 2.8 2.7 2.9 3.8 2.5 2.9 2.9 2.7

Izod Impact Strength: Measured according to ASTM D256 method. At this time, the thickness of the specimen was 1/4 inch.

- Surface gloss: measured with a Micro Haze Plus at 60 degrees.

Colorability (L): 0.5 parts by weight of a black coloring agent which is easy to identify was added to 100 parts by weight of the thermoplastic resin, and the L value was measured by using a spectral colorimeter (Datacolor 650). When the L value was low, it was judged that the coloring property was good.

- Injection retention thermal stability: The thermoplastic resin was retained in the screw of the extruder set at 240 캜 for 10 minutes, and then the degree of discoloration (? E) was shown by the following formula (2) , a and b values (measured values of a spectral colorimeter), and a value closer to 0 indicates an excellent thermal stability.

&Quot; (2) &quot;

? E = {(L-L ') ² + (a-a') ² + (b-b ') ² } ^1/2

As shown in Table 2, the rubbery polymer latexes of Examples 1 to 3 prepared according to the present invention had surface gloss and coloring similar to those of Comparative Example 1 in which polymer seeds were not used, but the Izod impact strength and injection stove thermal stability Is superior. Comparing Example 1 with Examples 1 to 3 and Comparative Example 3 using methyl-methacrylate having a lower refractive index than 1,3-butadiene as the conjugated diene monomer as the aromatic vinyl monomer, the Izod impact strength was remarkably improved, , Coloring property, and injection stability, and thermal stability.

In other words, referring to Tables 1 and 2, the rubbery polymer latexes of Examples 1 to 3 prepared according to the present invention had excellent productivity in a short reaction time as compared with Comparative Examples 1 to 5, And it is seen that the appearance quality is improved while maintaining the impact strength as compared with Comparative Examples 2 to 4. In addition, it was experimentally confirmed that the use of an aromatic vinyl monomer having a high refractive index as a polymer seed was effective for improving the appearance quality as compared with Comparative Example 3.

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 (15)

(a) 5 to 15 parts by weight of an aromatic vinyl monomer, 0.2 to 1.0 part by weight of a polymerization initiator, and 0.01 to 0.2 parts by weight of a first emulsifier to prepare a polymer seed having an average particle diameter of 2,000 to 2,500 angstroms;
(b) 85 to 95 parts by weight of the polymer seed and the conjugated diene monomer in the presence of 0.1 to 1.0 part by weight of the molecular weight modifier, 0.1 to 1.0 part by weight of the electrolyte and 1.5 to 2.5 parts by weight of the second emulsifier, %; And
(c) reacting the product of step (b) with the conjugated diene monomer in the presence of 0.1 to 1.0 part by weight of the third emulsifier so that the conversion ratio of the conjugated diene monomer is 90% or more, thereby preparing a polymer latex having an average particle size of 2,700 to 3,300 Å; &Lt; / RTI &gt; The method according to claim 1,
Wherein the aromatic vinyl monomer is one selected from the group consisting of styrene, alpha methyl styrene, alpha ethyl styrene, para methyl styrene, and a mixture of two or more thereof. The method according to claim 1,
Wherein the polymerization initiator is a persulfate-based initiator. The method of claim 3,
Wherein the persulfate-based initiator is one selected from the group consisting of sodium persulfate, potassium persulfate, ammonium persulfate, and a mixture of two or more thereof. The method according to claim 1,
Wherein the first, second and third emulsifiers are each selected from the group consisting of fatty acid soaps, alkali salts of rosin acid, alkylaryl sulfonates, alkaline methyl alkyl sulfates, sulfonated alkyl esters, and mixtures of two or more thereof By weight of the rubber latex. The method according to claim 1,
Wherein the molecular weight modifier is one selected from the group consisting of tert-butyl mercaptan, tert-dodecyl mercaptan, methyl mercaptan, and a mixture of two or more thereof. The method according to claim 1,
The electrolyte is a _{Na 2 SO 4, K 2 SO} 4, KCl, NaCl, KHCO 3, NaHCO 3, K 2 CO 3, Na 2 CO 3, KHSO 3, NaHSO 3, K 4 P 2 O 7, K 3 PO 4 , Na ₃ PO ₄ , Na ₂ HPO _4, and mixtures of two or more thereof. The method according to claim 1,
Wherein the conjugated diene monomer is at least one selected from the group consisting of 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, piperylene, 3 -butyl-1,3-octadiene, isoprene, Wherein the rubber latex is one selected from the group consisting of a mixture of two or more thereof. The method according to claim 1,
Wherein the temperatures in the steps (a) to (c) are Ta, Tb, and Tc,
Ta < Tb < Tc. 10. The method of claim 9,
Wherein the Ta is 45 to 55 占 폚. 10. The method of claim 9,
Wherein the Tb is 60 to 70 占 폚. 10. The method of claim 9,
Wherein the Tc is 70 to 80 占 폚. delete delete The method according to claim 1,
Wherein the polymer latex has a gel content of 75 to 90%.