KR102557040B1 - Acrylate compound-vinyl aromatic compound-vinylcyan compound copolymer and method for preparing the same copolymer - Google Patents

Abstract

The present invention relates to an acrylate compound-vinyl aromatic compound-vinyl cyan compound copolymer and a method for producing the same, and more particularly, to a vinyl acrylate-based rubber core containing two alkyl (meth)acrylate compounds under specific conditions. As a copolymer grafted with an aromatic compound and a vinyl cyan compound, it not only has excellent weather resistance, but also has a refractive index equal to or better than the conventional acrylic graft copolymer, but has a low glass transition temperature, which greatly improves the low-temperature impact strength of the product. It relates to an acrylate compound-vinyl aromatic compound-vinyl cyan compound copolymer and a method for preparing the same.

Description

Acrylate compound-vinyl aromatic compound-vinyl cyan compound copolymer and its preparation method

The present invention relates to an acrylate compound-vinyl aromatic compound-vinyl cyan compound copolymer and a method for producing the same, and more particularly, not only has excellent weather resistance, but also has a refractive index equivalent to or superior to conventional acrylic graft copolymers, and has a glass It relates to an acrylate compound-vinyl aromatic compound-vinyl cyan compound copolymer that can significantly improve the low-temperature impact strength of a product due to its low transition temperature.

In general, ABS-based resins obtained by graft copolymerization of aromatic vinyl monomers and vinyl cyan monomers to diene-based rubber polymers prepared by polymerization of conjugated diene-based monomers have excellent impact resistance and processability, excellent mechanical strength, heat distortion temperature, etc., and good colorability. Therefore, it is widely used in electrical and electronic products, automobile parts, and office equipment. However, since the rubber polymer used to manufacture the ABS-based resin contains chemically unstable unsaturated bonds, the rubber polymer is easily aged by ultraviolet rays and has a very poor weather resistance.

In order to improve these disadvantages, a method of using a chemically more stable acrylic rubber polymer instead of a conjugated diene-based rubber polymer containing a double bond has been proposed.

As described above, a representative example of a weather resistant thermoplastic resin using an acrylic rubber polymer not containing an unstable double bond is an acrylate compound-styrene-acrylonitrile (ASA) copolymer, which has an unstable double bond in the polymer. As it is not included, it has excellent weather resistance and is widely applied to various fields such as electrical and electronic parts, building materials (vinyl siding, etc.), profile extrusion, and automobile parts.

Conventional ASA-based resins exhibit poor low-temperature impact strength compared to ABS-based resins. This is because the glass transition temperature of the ABS-based resin is -80 ° C, whereas the glass transition temperature of the ASA-based resin is -50 ° C, which is relatively high. In order to overcome this, the monomer composition may be changed, but this is directly related to the refractive index of the material, causing another problem of lowering the refractive index.

Therefore, there is a need to develop an ASA-based resin having excellent low-temperature impact strength while maintaining high weather resistance and maintaining a refractive index equal to or higher than that of conventional acrylic graft copolymers.

Korean Patent Publication No. 2013-0001353 A

In order to solve the problems of the prior art as described above, the present invention maintains high weather resistance and lowers the glass transition temperature while maintaining the refractive index at a level equal to or higher than that of the conventional acrylic graft copolymer, ultimately significantly improving low-temperature impact strength. It is an object of the present invention to provide an acrylate compound-vinyl aromatic compound-vinyl cyan compound copolymer and a method for preparing the same.

Furthermore, another object of the present invention is to contribute to improving the quality of a specific product by utilizing the above-described acrylate compound-vinyl aromatic compound-vinyl cyan compound copolymer as an automobile exterior material or a building material.

The above and other objects of the present invention can all be achieved by the present invention described below.

In order to achieve the above object, the present invention seed; a rubber core surrounding the seed and including a first alkyl (meth)acrylate compound and a second alkyl (meth)acrylate compound; a rubber shell surrounding the rubber core and including a first alkyl (meth)acrylate compound; and a graft shell surrounding the rubber shell and including a vinyl aromatic compound and a vinyl cyan compound, wherein the first alkyl (meth) acrylate compound and the second alkyl (meth) acrylate compound are different, The alkyl group of the first alkyl (meth) acrylate compound is linear, the alkyl group of the second alkyl (meth) acrylate compound is linear or branched, and the alkyl group of the second alkyl (meth) acrylate compound accepts oxygen. Acrylic rubber-vinylaromatic compound-vinyl A cyanide compound copolymer is provided.

[Equation 1]

Y-X ≥ 2

[Equation 2]

Y-X ≥ 0

(In Equations 1 and 2, Y is the number of carbon atoms of the alkyl group of the second alkyl (meth) acrylate compound, and X is the number of carbon atoms of the alkyl group of the first alkyl (meth) acrylate compound.)

In addition, the present invention comprises a first step of preparing a seed by polymerizing a vinyl aromatic compound and a vinyl cyan compound; a second step of preparing a rubber core by polymerizing a first alkyl (meth)acrylate and a second alkyl (meth)acrylate compound in the presence of the seed; a third step of preparing a rubber shell by polymerizing a first alkyl (meth)acrylate in the presence of the rubber core; and a fourth step of preparing a graft shell by polymerizing an aromatic vinyl compound and a vinyl cyan compound in the presence of the rubber shell, wherein the first alkyl (meth) acrylate compound and the second alkyl (meth) The acrylate compound is different, the alkyl group of the first alkyl (meth) acrylate compound is linear, the alkyl group of the second alkyl (meth) acrylate compound is linear or branched, and the second alkyl (meth) acrylate When the alkyl group of the rate compound does not contain oxygen and has a linear structure, Equation 1 is satisfied, and when the alkyl group contains oxygen and has a linear structure, or when the alkyl group is branched, Equation 2 is satisfied. A method for producing a late compound-vinyl aromatic compound-vinyl cyan compound copolymer is provided.

According to the present invention, it has excellent weather resistance, a refractive index equal to or better than that of the conventional acrylic graft copolymer, and a low glass transition temperature, so that the low temperature impact strength of the product is greatly improved.

Hereinafter, the acrylate compound-vinylaromatic compound-vinyl cyan compound copolymer of the present disclosure and its preparation method will be described in detail.

For example, the acrylate compound-vinylaromatic compound-vinyl cyan compound copolymer of the present disclosure may include a seed; a rubber core surrounding the seed and including a first alkyl (meth)acrylate compound and a second alkyl (meth)acrylate compound; a rubber shell surrounding the rubber core and including a first alkyl (meth)acrylate compound; and a graft shell surrounding the rubber shell and including a vinyl aromatic compound and a vinyl cyan compound, wherein the first alkyl (meth) acrylate compound and the second alkyl (meth) acrylate compound are different, The alkyl group of the first alkyl (meth) acrylate compound is linear, the alkyl group of the second alkyl (meth) acrylate compound is linear or branched, and the alkyl group of the second alkyl (meth) acrylate compound accepts oxygen. When it does not contain and has a linear structure, the following Equation 1 is satisfied, and when the alkyl group contains oxygen and has a linear structure, or when the alkyl group is branched, Equation 2 below is satisfied.

[Equation 1]

Y-X ≥ 2

[Equation 2]

Y-X ≥ 0

(In Equations 1 and 2, Y is the number of carbon atoms of the alkyl group of the second alkyl (meth) acrylate compound, and X is the number of carbon atoms of the alkyl group of the first alkyl (meth) acrylate compound.)

The acrylate compound-vinyl aromatic compound-vinyl cyan compound copolymer of the present disclosure as described above is composed of a rubber core and a rubber shell of a specific composition, and in particular, first and second alkyl (meth) so as to satisfy Equation 1 or 2 above. Including an acrylate compound, it not only has excellent weather resistance, but also has a refractive index equal to or better than that of the conventional acrylic graft copolymer, and has a low glass transition temperature, thereby providing an effect of improving the low temperature impact strength of the product.

For example, the copolymer of the present substrate has a high refractive index of 1.4 to 1.6 or 1.40 to 1.55, preferably 1.40 to 1.50 or 1.42 to 1.46, and a glass transition temperature of -90 ° C to -50 ° C, -90 ° C to -54 ° C. °C, preferably -70 °C to -55 °C or -65 °C to -54 °C, providing excellent color and excellent impact strength, especially low-temperature impact strength.

The refractive index was measured by the method of JIS-K-7142 (23° C., wavelength 589 nm) using an Abbe refractometer on a specimen having a thickness of 1/8 inch (3.2 mm) unless otherwise specified.

The glass transition temperature was measured using TA instrument's DSC equipment (device name: DSC 2920) unless otherwise specified.

For example, the copolymer of the present substrate has an excellent low-temperature (-30 ° C) Izod impact strength of 6 J / m or more, 6 to 15 J / m, and preferably 8.5 to 15 J / m, so that the low temperature of the product when used as an automobile or building exterior material Impact resistance can be improved.

Unless otherwise specified, the low-temperature Izod impact strength was measured according to the ISO 180A method using a specimen having a thickness of 6.4 mm, and measured at a low temperature (-30 ° C) after notching the specimen.

Hereinafter, each component constituting the acrylate compound-vinyl aromatic compound-vinyl cyan compound copolymer of the present description will be described in detail.

seed

The seed may include, for example, a vinyl aromatic compound-vinyl cyan compound copolymer. In this case, the refractive index of the copolymer is maintained high, and the appearance quality of the final product, such as colorability, is excellent.

The vinyl aromatic compound may be, for example, at least one selected from styrene, α-methylstyrene, p-methylstyrene, t-butyl styrene, halogen-substituted styrene, dimethylstyrene, and ethyl styrene, and preferably styrene.

The vinyl cyanide compound may be, for example, at least one selected from acrylonitrile, methacrylonitrile, ethacrylonitrile, and the like, preferably acrylonitrile.

The seed may be preferably in the range of 3 to 20 parts by weight or 4 to 10 parts by weight based on the total of 100 parts by weight of the monomers constituting the rubber core, rubber shell and graft shell of the present substrate, and more preferably It may be within the range of 10 parts by weight, and in this case, the impact resistance and refractive index of the copolymer are maintained high.

The weight ratio of the vinyl aromatic compound and the vinyl cyan compound constituting the seed may be, for example, 3.5: 1 to 5: 1 or 3.5: 1 to 4.5: 1, and within this range, the refractive index of the copolymer is maintained high without deterioration. It can be.

rubber core and rubber shell

The rubber core and the rubber shell may be preferably within the range of 20 to 60% by weight or 30 to 55% by weight, for example, based on the total weight of the copolymer of the present substrate. In this case, the copolymer has excellent impact resistance, weather resistance, and the like, and a refractive index can be kept high.

Unless otherwise defined, the total weight of the copolymer of the present description means the total weight of the monomers constituting the seed, rubber core, rubber shell, and graft shell, which may be replaced by the total weight of the prepared copolymer.

As another example, the rubber core and the rubber shell have a total weight of 40 to 70 parts by weight or 50 to 65 parts by weight based on 100 parts by weight of the total monomers constituting the rubber core, rubber shell and graft shell of the present description. It may be preferable, and more preferably within the range of 55 to 65 parts by weight, in this case, the low-temperature impact resistance and refractive index of the copolymer are maintained high.

The copolymer of the present substrate may be characterized in that the rubber core and the rubber shell contain two specific alkyl (meth)acrylate compounds so as to lower the glass transition temperature of the material and ultimately improve low-temperature impact resistance.

The two types of alkyl (meth) acrylates are named as a first alkyl (meth) acrylate compound and a second alkyl (meth) acrylate, respectively, and it is specified that they are not the same.

The alkyl group of the first alkyl (meth) acrylate compound may be linear, the alkyl group of the second alkyl (meth) acrylate compound may be linear or branched, and to achieve the objects and effects of the present invention, the first and The second alkyl (meth)acrylate compound is characterized by satisfying Equation 1 or Equation 2 below.

For example, when the alkyl group of the second alkyl (meth)acrylate compound does not contain oxygen and has a linear structure and satisfies Equation 1 below, the glass transition temperature is lowered while the refractive index of the copolymer is maintained high within a specific range. As a result, the low temperature impact strength is improved.

[Equation 1]

Y-X ≥ 2

(In Equation 1, Y is the number of carbon atoms of the alkyl group of the second alkyl (meth) acrylate compound, and X is the number of carbon atoms of the alkyl group of the first alkyl (meth) acrylate compound.)

As a preferred example, Y-X in Equation 1 may be 2 or more, 4 or more, or 4 to 15, and in this case, the low-temperature impact strength is further improved while the refractive index of the copolymer is maintained high.

A specific example corresponding to this is that the first alkyl (meth) acrylate compound is n-butyl (meth) acrylate, and the second alkyl (meth) acrylate compound is n-hexyl (meth) acrylate, n-heptyl (meth) acrylate. )Acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, n-decyl (meth)acrylate, n-undecyl (meth)acrylate, n-dodecyl (meth)acrylate The case of at least one selected from the like is exemplified.

As another example, when the alkyl group of the second alkyl (meth)acrylate compound is an alkyl of a linear structure containing oxygen and satisfies Equation 2 below, the glass transition temperature is lowered while the refractive index of the copolymer is maintained high, resulting in low-temperature impact strength can be greatly improved.

A specific example corresponding to this is that the first alkyl (meth) acrylate compound is n-butyl (meth) acrylate, and the second alkyl (meth) acrylate compound is 2-ethoxyethyl (meth) acrylate, 3- A case of at least one selected from oxypropyl (meth)acrylate and the like may be exemplified.

As another example, when the alkyl group of the second alkyl (meth)acrylate compound has a branched structure and satisfies Equation 2, the glass transition temperature is lowered while the refractive index of the copolymer is maintained high, thereby improving low-temperature impact strength. provides

As a preferred example, in Equation 2, Y-X may be 0 or more, 2 or more, or 4 to 15, in which case the low-temperature impact strength may be further improved while the refractive index of the copolymer is maintained high.

A specific example corresponding to this is that the first alkyl (meth) acrylate compound is n-butyl (meth) acrylate, and the second alkyl (meth) acrylate compound is tert-butyl (meth) acrylate, branched hexyl (meth) ) A case in which at least one selected from acrylates and the like is exemplified.

In a preferred example, the alkyl group of the first alkyl (meth)acrylate compound is linear, and the alkyl group of the second alkyl (meth)acrylate compound is branched, and may satisfy Equation 3 below. In this case, the copolymer While the refractive index is maintained high, low-temperature impact strength can be greatly improved.

[Equation 3]

Y-X ≥ 3

A corresponding specific example thereof is a case in which the first alkyl (meth)acrylate compound is n-butyl acrylate and the second alkyl (meth)acrylate compound is 2-ethylhexyl acrylate. In the case of the copolymer, the refractive index of the copolymer is not lowered, the weather resistance is excellent, and the low-temperature impact resistance can be further improved by lowering the glass transition temperature.

For example, based on the total weight of the rubber core and the rubber shell, the first alkyl (meth)acrylate compound is included in 60 to 85% by weight, and the second alkyl (meth)acrylate compound is 15 to 40% by weight Within this range, low-temperature impact strength can be improved by lowering the glass transition temperature while maintaining a high refractive index of the copolymer.

In another example, based on the total weight of the rubber core and the rubber shell, the first alkyl (meth)acrylate compound is included in 70 to 85% by weight and the second alkyl (meth)acrylate compound is 15 to 30% by weight It may be included, and provides an advantage of further improving low-temperature impact strength while maintaining a high refractive index of the copolymer within this range.

In a preferred example, based on the total weight of the rubber core and the rubber shell, the first alkyl (meth)acrylate compound is included in 75 to 85% by weight and the second alkyl (meth)acrylate compound is 15 to 25% by weight Within this range, the weather resistance of the copolymer is excellent, the refractive index is maintained high, and the low-temperature impact strength is greatly improved.

The weight ratio of the first alkyl (meth)acrylate compound and the second alkyl (meth)acrylate compound included in the rubber core and the rubber shell is, for example, 1:5 to 2:1, 1:4 to 2:1, preferably Preferably it may be 1:5 to 1:1 or 2:1 to 1:1, preferably 3:1 to 2:1, and within this range, the copolymer has excellent weatherability and a high refractive index The glass transition temperature can be lowered while maintaining, and as a result, the low-temperature impact strength can be greatly improved.

Hereinafter, each of the rubber core and rubber shell will be described in detail.

rubber core

The rubber core surrounds the seed and includes a first alkyl (meth)acrylate compound and a second alkyl (meth)acrylate compound, thereby lowering the glass transition temperature while maintaining a high refractive index of the copolymer, thereby improving low-temperature impact strength. can provide an improving effect.

The first alkyl (meth)acrylate compound and the second alkyl (meth)acrylate compound included in the rubber core may be included in a weight ratio of, for example, 1:0.5 to 1:20, preferably 1:1 to 1 : It may be included in a weight ratio of 10, more preferably in a weight ratio of 1:1 to 1:3 or 1:3 to 1:10, while maintaining a high refractive index of the copolymer within this range, the glass transition temperature It is possible to provide an effect of improving low-temperature impact strength by lowering.

rubber shell

The rubber shell surrounds the rubber core and includes a first alkyl (meth)acrylate compound, and in this case, the transparency of the copolymer prepared by minimizing the change in refractive index by the rubber core, that is, increasing the refractive index, and There is an advantage of improving colorability and the like.

graft shell

The graft shell surrounds the rubber shell and includes a vinyl aromatic compound and a vinyl cyan compound.

The graft shell may preferably be in the range of 20 to 60% by weight or 30 to 50% by weight, for example, based on the total weight of the copolymer of the present substrate, and in this case, the weather resistance, impact resistance, and refractive index of the copolymer can be satisfied at the same time .

As another example, the graft shell may preferably be in the range of 30 to 60 parts by weight or 35 to 50 parts by weight based on the total of 100 parts by weight of the rubber core, rubber shell, and monomers constituting the graft shell of the present description, More preferably, it may be within the range of 35 to 45 parts by weight, and in this case, the advantage of maintaining high low-temperature impact resistance and refractive index of the copolymer is provided.

The vinyl aromatic compound may be, for example, at least one selected from styrene, α-methylstyrene, p-methylstyrene, t-butyl styrene, halogen-substituted styrene, dimethylstyrene, and ethyl styrene, and preferably styrene.

The vinyl cyanide compound may be, for example, at least one selected from acrylonitrile, methacrylonitrile, ethacrylonitrile, and the like, preferably acrylonitrile.

The weight ratio of the vinyl aromatic compound and the vinyl cyan compound constituting the graft shell may be, for example, 4:1 to 2.5:1 or 3.5:1 to 2.8:1, and the refractive index of the copolymer does not decrease within this range. can be kept high.

The copolymer of the present description composed of the seed, the rubber core, the rubber shell, and the graft shell includes, for example, 40 to 70% by weight of the first and second alkyl (meth)acrylate compounds based on the total weight thereof; 20 to 40% by weight of a vinyl aromatic compound; And 10 to 30% by weight of a vinyl cyan compound; in this case, the refractive index of the copolymer is maintained high while providing excellent weather resistance and low-temperature impact strength.

As another example, the copolymer of the present disclosure composed of the seed, the rubber core, the rubber shell, and the graft shell contains 55 to 65% by weight of the first and second alkyl (meth)acrylate compounds based on the total weight thereof; 25 to 35% by weight of a vinyl aromatic compound; And 10 to 20% by weight of a vinyl cyan compound; in this case, the refractive index of the copolymer is maintained high while providing excellent weather resistance and low-temperature impact strength.

Hereinafter, a method for preparing the above-described acrylate-vinylaromatic compound-vinylcyanide compound copolymer of the present description will be described in detail, which shares technical characteristics with the above-described acrylate-vinylaromatic compound-vinylcyanate copolymer. As such, descriptions overlapping with the above will be omitted.

The method for preparing the acrylate compound-vinyl aromatic compound-vinyl cyan compound copolymer of the present disclosure includes, for example, a first step of preparing a seed by polymerizing a vinyl aromatic compound and a vinyl cyan compound; a second step of preparing a rubber core by polymerizing a first alkyl (meth)acrylate and a second alkyl (meth)acrylate compound in the presence of the seed; a third step of preparing a rubber shell by polymerizing a first alkyl (meth)acrylate in the presence of the rubber core; A fourth step of preparing a graft shell by polymerizing an aromatic vinyl compound and a vinyl cyan compound in the presence of the rubber shell; including, the first alkyl (meth) acrylate compound and the second alkyl (meth) acryl The rate compound is different, the alkyl group of the first alkyl (meth) acrylate compound is linear, the alkyl group of the second alkyl (meth) acrylate compound is linear or branched, and the second alkyl (meth) acrylate compound When the alkyl group of the compound does not contain oxygen and has a linear structure, Equation 1 is satisfied, and when the alkyl group contains oxygen and has a linear structure, or when the alkyl group is branched, Equation 2 is satisfied. , The copolymer prepared in this way has excellent weatherability and maintains a high refractive index, but has a low glass transition temperature, ultimately providing an advantage of improving low-temperature impact strength.

The first to fourth steps may be prepared according to a polymerization method well known in the art, for example, emulsion polymerization.

In the detailed description of the manufacturing method of the present substrate below, unless otherwise specified, the weight parts of each material added to the reaction are the first and second alkyl (meth)acrylate compounds and vinyl aromatic compounds introduced during the copolymer production. and vinyl cyan compounds based on a total of 100 parts by weight.

As a preferred example, in the first step, a seed may be prepared by polymerizing 4 to 10 parts by weight of a monomer mixture containing a vinyl aromatic compound and a vinyl cyan compound, wherein 0.05 to 0.8 parts by weight of an electrolyte, 0.01 to 0.8 parts by weight of a crosslinking agent, It may include 0.01 to 3 parts by weight of an initiator and 0.03 to 0.25 parts by weight of an emulsifier.

In a preferred example, the second step includes 40 to 55 parts by weight of a monomer mixture including a first alkyl (meth)acrylate and a second alkyl (meth)acrylate compound and 0.02 to 0.8 parts by weight of a crosslinking agent in the presence of the seed. A rubber core may be prepared by polymerization, and in this case, 0.01 to 0.09 parts by weight of an initiator and 0.2 to 0.9 parts by weight of an emulsifier may be included.

As a preferred example, in the third step, a rubber shell may be prepared by polymerization by adding 5 to 20 parts by weight of the first alkyl (meth)acrylate in the presence of the rubber core.

As a preferred example, in the fourth step, a graft shell may be prepared by polymerizing 40 to 50 parts by weight of a monomer mixture including an aromatic vinyl compound and a vinyl cyan compound in the presence of the rubber shell, wherein 0.05 to 2.5 parts by weight of an initiator , 0.01 to 0.8 parts by weight of a molecular weight modifier and 0.2 to 2.8 parts by weight of an emulsifier.

The acrylate compound-vinyl aromatic compound-vinyl cyan compound copolymer of the present description prepared as an example as described above provides excellent weather resistance and low-temperature impact resistance, and, if necessary, such as a vinyl aromatic compound-vinyl cyan compound copolymer, etc. The hard matrix copolymer may be included within the range of 30 to 70% by weight, preferably 50 to 60% by weight, and more preferably 55 to 60% by weight based on the total weight of the resin composition, and thereby utilized as an automobile or building exterior material. It can contribute to improving product quality.

In describing the copolymer of the present description and its manufacturing method, other additives or manufacturing conditions not specifically specified are not particularly limited and may be appropriately selected as long as they are within the range commonly practiced in the art.

Hereinafter, preferred embodiments are presented to aid understanding of the present invention, but the following examples are merely illustrative of the present invention, and various changes and modifications are possible within the scope and spirit of the present invention. It is obvious to those skilled in the art, It goes without saying that these variations and modifications fall within the scope of the appended claims.

[Example]

The parts by weight of each material added to the reaction below are based on 100 parts by weight of the total of monomers constituting the rubber core, rubber shell, and graft shell.

Example 1

<Preparation of seed>

In a nitrogen-purged reactor, 4.8 parts by weight of styrene, 1.2 parts by weight of acrylonitrile, 0.1 part by weight of sodium dicyclohexyl selphosuccinate (trade name: A196, manufacturer: SOLVAY, critical micelle concentration: 3% by weight) as an emulsifier, and a crosslinking agent 0.03 parts by weight of ethylene glycol dimethacrylate, 0.02 parts by weight of allyl methacrylate as a grafting agent, 0.025 parts by weight of KOH and 53.32 parts by weight of distilled water as electrolytes were collectively added, heated to 70 ° C, and 0.03 parts by weight of potassium persulfate as an initiator The portion was added at once to initiate polymerization. After polymerization for 1 hour, the polymerization was terminated to obtain seeds.

<Manufacture of rubber core and shell>

20 parts by weight of butyl acrylate, 20 parts by weight of 2-ethylhexyl acrylate, 0.6 parts by weight of sodium dodecyl sulfate as an emulsifier, 0.1 part by weight of ethylene glycol dimethacrylate as a crosslinking agent, grafting A mixture of 0.04 parts by weight of zero allyl methacrylate, 30 parts by weight of distilled water, and 0.05 parts by weight of potassium persulfate as an initiator was polymerized while being continuously added at a constant rate at 70 ° C. for 3 hours, and then 20 parts by weight of butyl acrylate as a rubber shell After adding the part for 1 hour, the polymerization was further conducted for 1 hour, and then the mixture was terminated to obtain a core-shell structured rubber covering the seed.

<Manufacture of graft shell>

32 parts by weight of styrene, 12 parts by weight of acrylonitrile, and 39 parts by weight of distilled water were added to the reactor in which the rubber was obtained, 1.9 parts by weight of sodium rosinate as an emulsifier, and 0.19 part by weight of t-butylperoxyethylhexyl carbonate as an initiator. and a second mixture containing 0.16 parts by weight of sodium pyrophosphate, 0.24 parts by weight of dextrose, and 0.004 parts by weight of ferrous sulfide as activators, respectively, at 75 ° C. for 2.5 hours at a constant rate while polymerizing. After the continuous addition was completed, the reaction was further conducted at 75° C. for 1 hour and cooled to 60° C. to terminate the polymerization reaction to prepare a graft copolymer latex including a graft shell.

<Manufacture of Graft Copolymer Powder>

0.8 parts by weight of an aqueous solution of calcium chloride (concentration: 23% by weight) was applied to the graft copolymer latex, coagulated at 70 ° C. for 7 minutes under normal pressure, aged at 93 ° C. for 7 minutes, dehydrated and washed, and then 90 ° C. It was dried with hot air for 30 minutes to prepare a graft copolymer powder.

<Preparation of thermoplastic resin composition>

A thermoplastic resin composition containing 44% by weight of the graft copolymer powder and 56% by weight of a hard matrix copolymer (trade name: 90HR, manufacturer: LG Chem) was prepared.

Example 2

As shown in Table 1 below, in <Preparation of rubber core and shell> of Example 1, the input amount of 2-ethylhexyl acrylate was changed to 30 parts by weight and the input amount of butyl acrylate to 10 parts by weight when preparing the rubber core. It was carried out in the same manner as in Example 1 except for the above.

Example 3

As shown in Table 1 below, the amount of 2-ethylhexyl acrylate added to 50 parts by weight and the amount of butyl acrylate changed to 5 parts by weight when preparing the rubber core in <Preparation of rubber core and shell> of Example 1, In addition, the same procedure as in Example 1 was carried out except that the amount of butyl acrylate was changed to 5 parts by weight when preparing a rubber shell.

Comparative Example 1

As shown in Table 1 below, 2-ethylhexyl acrylate was omitted and n-butyl acrylate was changed to 60 parts by weight when preparing the rubber core in <Preparation of rubber core and shell> of Example 1, and rubber It was carried out in the same manner as in Example 1, except that butyl acrylate was omitted when preparing the shell.

Comparative Example 2

As shown in Table 1 below, the addition of 2-ethylhexyl acrylate was omitted during the preparation of the rubber core in <Preparation of the rubber core and shell> of Example 1, and the graft shell was prepared in <Manufacture of the graft shell> It was carried out in the same manner as in Example 1, except that 20 parts by weight of 2-ethylhexyl acrylate was further added.

Comparative Example 3

As shown in Table 1 below, 2-ethylhexyl acrylate was omitted when preparing the rubber core in <Preparation of the rubber core and shell> of Example 1, and 20 parts by weight of 2-ethylhexyl acrylate was added when preparing the rubber shell. It was carried out in the same manner as in Example 1 except that additional input was added.

[Test Example]

The properties of the ASA copolymers prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were measured by the following method, and the results are shown in Table 1 below.

* Refractive index:

It was measured by the method of JIS-K-7142 (23 ° C, wavelength 589 nm) using an Abbe refractometer for a 1/8 inch (3.2 mm) thick specimen.

* Glass transition temperature (Tg, unit: ℃):

It was measured using TA instrument's DSC equipment (device name: DSC 2920).

* Low temperature Izod impact strength (unit: J/m):

It was measured according to the ISO 180A method using a specimen of 1/4 inch (6.4 mm) in thickness, and measured at a low temperature (-30 ° C) after notching the specimen.

(unit: parts by weight) Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 seed ST 4.8 4.8 4.8 4.8 4.8 4.8 AN 1.2 1.2 1.2 1.2 1.2 1.2 rubber core BA 20 10 5 60 40 20 2-EHA 20 30 50 - - - rubber shell BA 20 20 5 - - 20 2-EHA - - - - - 20 graft shell ST 30 30 30 30 30 30 AN 10 10 10 10 10 10 2-EHA - - - - 20 - refractive index 1.46 1.46 1.42 1.46 1.43 1.42 Tg (℃) -54 -60 -65 -50 -50 -53 Low temperature Izod impact strength (J/m) 8.4 10.8 12.9 5.0 5.2 8.2

(In the above table, the total weight of each monomer component constituting the rubber core, rubber shell, and graft shell is based on 100 parts by weight, BA is n-butyl acrylate, 2-EHA is 2-ethylhexyl acrylate, ST is Styrene, AN stands for acrylonitrile.)

As shown in Table 1, the ASA copolymers of Examples 1 to 3 prepared according to the present invention have an equivalent refractive index compared to the copolymer of Comparative Example 1 in which butyl acrylate was applied alone as a monomer when preparing a rubber core. It can be seen that the glass transition temperature is lowered while maintaining, and accordingly, it can be confirmed that the low temperature impact strength is greatly improved.

In particular, in the case of Examples 2 and 3 in which the content of the 2-ethylhexyl acrylate monomer contained in the rubber core is 30 to 50 parts by weight, it can be seen that the low-temperature impact strength is improved by more than two times compared to Comparative Example 1.

In addition, referring to Comparative Example 2, when 2-ethylhexyl acrylate is added during the manufacture of a graft shell rather than a rubber core, the glass transition temperature is not lowered even though the same amount of 2-ethylhexyl acrylate as in Example 1 is included. However, it was confirmed that the effect of improving the low-temperature impact strength was very weak.

In addition, referring to Comparative Example 3, when 2-ethylhexyl acrylate is added during the manufacture of a rubber shell rather than a rubber core, the refractive index drops significantly even though the same amount of 2-ethylhexyl acrylate as in Example 1 is included. It could be easily expected that the colorability and transparency would be greatly reduced.

Claims (11)

seed; a rubber core surrounding the seed and including a first alkyl (meth)acrylate compound, a second alkyl (meth)acrylate compound, and a crosslinking agent; a rubber shell surrounding the rubber core and including a first alkyl (meth)acrylate compound; And a graft shell surrounding the rubber shell and containing a vinyl aromatic compound and a vinyl cyan compound;
The first alkyl (meth) acrylate compound and the second alkyl (meth) acrylate compound are different,
The alkyl group of the first alkyl (meth) acrylate compound is linear, the alkyl group of the second alkyl (meth) acrylate compound is linear or branched,
When the alkyl group of the second alkyl (meth)acrylate compound has a linear structure containing no oxygen, Equation 1 is satisfied, and when the alkyl group has a linear structure containing oxygen or when the alkyl group is branched, Equation 2 below is satisfied,
The seed includes an aromatic compound and a vinyl cyan compound, and the weight ratio of the vinyl aromatic compound and the vinyl cyan compound is 3.5: 1 to 4.5: 1,
The first alkyl (meth) acrylate compound and the second alkyl (meth) acrylate compound included in the rubber core are included in a weight ratio of 1: 3 to 1: 10, characterized in that
An acrylate compound-vinyl aromatic compound-vinyl cyan compound copolymer.
[Equation 1]
YX ≥ 2
[Equation 2]
YX ≥ 0
(In Equations 1 and 2, Y is the number of carbon atoms of the alkyl group of the second alkyl (meth) acrylate compound, and X is the number of carbon atoms of the alkyl group of the first alkyl (meth) acrylate compound.) According to claim 1,
The copolymer is characterized in that the glass transition temperature is -90 ℃ to -50 ℃
An acrylate compound-vinyl aromatic compound-vinyl cyan compound copolymer. According to claim 1,
The copolymer is characterized in that the refractive index is 1.4 to 1.6
An acrylate compound-vinyl aromatic compound-vinyl cyan compound copolymer. According to claim 1,
The copolymer comprises 40 to 70% by weight of the first and second alkyl (meth)acrylate compounds based on the total weight of the seed, rubber core, rubber shell and graft shell; 20 to 40% by weight of a vinyl aromatic compound; And 10 to 30% by weight of a vinyl cyan compound; characterized in that it comprises
An acrylate compound-vinyl aromatic compound-vinyl cyan compound copolymer. According to claim 1,
The alkyl group of the first alkyl (meth) acrylate compound is linear, the alkyl group of the second alkyl (meth) acrylate compound is branched, Equation 3
[Equation 3]
YX ≥ 3
characterized in that it satisfies
An acrylate compound-vinyl aromatic compound-vinyl cyan compound copolymer. According to claim 1,
The first alkyl (meth) acrylate compound is n-butyl (meth) acrylate, and the second alkyl (meth) acrylate compound is tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, Characterized in that at least one selected from 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, and 2-ethoxyethyl acrylate
An acrylate compound-vinyl aromatic compound-vinyl cyan compound copolymer. delete According to claim 1,
The rubber core and the rubber shell, based on the total weight of the first alkyl (meth) acrylate compound 60 to 85% by weight; And a second alkyl (meth) acrylate compound 15 to 40% by weight; characterized in that it comprises a
An acrylate compound-vinyl aromatic compound-vinyl cyan compound copolymer. According to claim 1,
The weight ratio of the first alkyl (meth) acrylate compound and the second alkyl (meth) acrylate compound contained in the rubber core and the rubber shell is 1: 5 to 2: 1, characterized in that
An acrylate compound-vinyl aromatic compound-vinyl cyan compound copolymer. According to claim 1,
The copolymer is characterized in that the low temperature (-30 ℃) Izod impact strength of 6 J / m or more
An acrylate compound-vinyl aromatic compound-vinyl cyan compound copolymer. A first step of preparing a seed by polymerizing a vinyl aromatic compound and a vinyl cyan compound;
A second step of preparing a rubber core by polymerizing a first alkyl (meth)acrylate, a second alkyl (meth)acrylate compound, and a crosslinking agent in the presence of the seed;
a third step of preparing a rubber shell by polymerizing a first alkyl (meth)acrylate in the presence of the rubber core;
A fourth step of preparing a graft shell by polymerizing an aromatic vinyl compound and a vinyl cyan compound in the presence of the rubber shell;
The first alkyl (meth) acrylate compound and the second alkyl (meth) acrylate compound are different,
The alkyl group of the first alkyl (meth) acrylate compound is linear, the alkyl group of the second alkyl (meth) acrylate compound is linear or branched,
When the alkyl group of the second alkyl (meth)acrylate compound does not contain oxygen and has a linear structure, Equation 1 below is satisfied, and when the alkyl group contains oxygen and has a linear structure or when the alkyl group has a branched structure, Equation 2 below is satisfied,
The seed has a weight ratio of a vinyl aromatic compound and a vinyl cyan compound of 3.5: 1 to 4.5: 1,
The first alkyl (meth) acrylate compound and the second alkyl (meth) acrylate compound included in the rubber core are included in a weight ratio of 1: 3 to 1: 10, characterized in that
Method for producing an acrylate compound-vinyl aromatic compound-vinyl cyan compound copolymer.
[Equation 1]
YX ≥ 2
[Equation 2]
YX ≥ 0
(In Equations 1 and 2, Y is the number of carbon atoms of the alkyl group of the second alkyl (meth) acrylate compound, and X is the number of carbon atoms of the alkyl group of the first alkyl (meth) acrylate compound.)