KR101997520B1 - Methylmethacrylate-butadiene-styrene type graft copolymer and method for preparing the same - Google Patents

Abstract

The present invention relates to a methyl methacrylate-butadiene-styrene (MBS) graft copolymer having a core-shell-shell (CSS) structure and a method for producing the same. More specifically, the present invention relates to a butadiene rubber polymer core; And a dual graft shell coated on the surface of the rubber polymer core, wherein the dual graft shell comprises a first graft shell consisting of surface modified nanosilica; And a second graft shell consisting of a copolymer of an alkyl acrylate monomer and an ethylenically unsaturated aromatic monomer, and a process for producing the same.

Description

METHYL METHACRYLATE-BUTADIENE-STYRENE TYPE GRAFT COPOLYMER AND METHOD FOR PREPARING THE SAME [0001] The present invention relates to a methyl methacrylate-butadiene-styrene graft copolymer,

TECHNICAL FIELD The present invention relates to a methyl methacrylate-butadiene-styrene graft copolymer for an impact modifier, which can be used in the production of a thermoplastic resin, and a process for producing the same.

A vinyl chloride (PVC) resin is one of thermoplastic resins containing 50% or more of vinyl chloride and is a general-purpose resin widely used in various fields such as semiconductors or automobiles.

Since the vinyl chloride resin is very weak to the impact, the processing temperature is close to the thermal decomposition temperature, the temperature range in which the resin can be formed is narrow, the melt viscosity is high and the fluidity is low, It is known to cause problems such as deterioration of quality.

Methods for overcoming the disadvantages of such vinyl chloride resins have been studied for a long time.

For example, in order to improve the impact resistance of a vinyl chloride resin, methylmethacrylate-butadiene-styrene (hereinafter, abbreviated as "methylmethacrylate-butadiene-styrene") prepared by grafting a monomer such as styrene and methyl methacrylate to a rubber polymer containing butadiene as a substrate -styrene (hereinafter referred to as "MBS") based graft copolymer as an impact modifier.

However, it is known that the MBS-based graft copolymer differs in the physical properties of the vinyl chloride resin obtained depending on the content of the grafted monomer, the polymerization method, the content of the rubber polymer used as the substrate, the particle size, and the like.

For example, when the content and the particle size of the rubber polymer used as the substrate of the MBS-based graft copolymer are increased in order to improve the impact strength, the transparency of the resulting vinyl chloride resin is lowered due to light scattering or the like have. In addition, there is a large difference in refractive index between the particles of the vinyl chloride resin and the MBS-based graft copolymer, and the bonding strength between the MBS-based graft copolymer and the vinyl chloride resin is weakened at the time of deformation, , The impact strength and whitening characteristics are deteriorated. Therefore, when the particle size of the rubber polymer in the MBS-based graft copolymer is increased or the rubber content is increased in the general emulsion polymerization, the impact resistance of the thermoplastic resin is improved, but in the applications requiring high transparency, And it is difficult to secure the whiteness characteristics.

Therefore, it is urgently required to develop an impact modifier that improves the impact resistance which causes a problem in increasing the rubber polymer content while maintaining the transparency in the production of vinyl chloride resin, and the property of protrusion which causes a decrease in the surface condition of the product after processing.

Korean Patent Registration No. 10-0398737

Disclosure of Invention Technical Problem [8] The present invention has been conceived to solve the problems of the prior art, and provides MBS-based graft copolymer for impact modifier having improved impact properties by including a shell made of surface-modified nano silica.

In addition, the present invention provides a method for producing an MBS-based graft copolymer for the impact modifier.

In order to solve the above problems,

In one embodiment of the present invention

Butadiene-based rubber polymer core; And

A double graft shell coated on the surface of the rubber polymer core,

The double grafted shell

A first graft shell consisting of functionalized nanosilica; And

A second grafted shell made of a copolymer of an alkyl acrylate monomer and an ethylenically unsaturated aromatic monomer.

In the present invention,

(a) preparing a butadiene-based rubber polymer core by emulsion polymerization;

(b) preparing surface-modified nanosilica;

(c) preparing a copolymer of the butadiene-based rubber polymer core and the core-shell structure by first emulsion graft-polymerizing the surface-modified nanosilica; And

(d) preparing a graft copolymer of a core-shell-shell structure by secondary emulsion graft-polymerizing a copolymer of the core-shell structure prepared above with an alkyl acrylate monomer and an ethylenically unsaturated aromatic monomer, The present invention provides a method for producing an MBS-based graft copolymer for an impact modifier.

As described above, according to the present invention, MBS-based graft copolymers having improved physical properties such as impact strength and elongation by including a double grafted shell containing surface-modified nano silica on the surface of a butadiene- A manufacturing method can be provided.

Hereinafter, the present invention will be described in detail in order to facilitate understanding of the present invention.

The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms and the inventor may appropriately define the concept of the term in order to best describe its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.

The methyl methacrylate-butadiene-styrene (MBS) graft copolymer, which is conventionally used as an impact modifier of a vinyl chloride resin, is composed of a rubber polymer core and a shell surrounding the core surface, and improves the impact resistance There is a disadvantage in that transparency and whitening resistance, lowering of glass transition temperature, and change of refractive index occur when the rubber content in the impact modifier is increased. Accordingly, the inventors of the present invention have found that when graft copolymer used as an impact modifier in the production of vinyl chloride resin is introduced, functionalized nanosilica is introduced during the emulsion polymerization process, It is possible to improve transparency, impact properties and protrusion properties of vinyl chloride resin, and on the basis thereof, an impact modifier for vinyl chloride resin having excellent physical properties over conventional manufacturing methods and a manufacturing method thereof are completed.

That is, in the present invention, a butadiene-based rubber polymer core, a first graft shell made of surface-modified nanosilica that surrounds the rubber polymer core, and an alkyl acrylate monomer wrapped around the first graft shell surface and an ethylene- (MBS) graft copolymer for an impact modifier having a core-shell-shell structure and a second graft shell composed of a copolymer of an unsaturated aromatic monomer and a method for producing the same As a technical feature.

Hereinafter, the present invention will be described in detail.

(A) MBS-based graft copolymer for impact modifier of core-shell-shell structure

First, in an embodiment of the present invention

Butadiene-based rubber polymer core; And

A double graft shell coated on the surface of the rubber polymer core,

The double grafted shell

A first graft shell consisting of surface modified nanosilica; And

A second grafted shell made of a copolymer of an alkyl acrylate monomer and an ethylenically unsaturated aromatic monomer.

Specifically, the MBS-based graft copolymer of the present invention

i) from 55 to 65% by weight of a butadiene-based rubber polymer core;

ii) 5 to 15% by weight of a first graft shell consisting of a surface modified nanosilica coated on the surface of said rubber polymer core; And

iii) 25 to 30% by weight of a second graft shell consisting of a copolymer of an alkyl acrylate monomer and an ethylenically unsaturated aromatic monomer coated on the surface of the first graft shell.

At this time, in the MBS-based graft copolymer of the core-shell-shell structure of the present invention, when the content of the butadiene rubber polymer core (i) is less than 55% by weight, If it exceeds the weight%, the projecting property and elongation tend to be lowered, which is not preferable.

In the MBS-based graft copolymer of the core-shell-shell structure of the present invention, the double grafted shell imparts compatibility with the thermoplastic resin to the MBS-based graft copolymer, and the impact strength of the rubber polymer core To be able to exert a good effect. At this time, it is important to coat the shell well so that the rubber polymer core can be well dispersed. However, if the shell is coated too thickly, impact can not be transmitted to the core when an external impact is received.

In particular, the MBS-based graft copolymer of the core-shell-shell structure of the present invention can be obtained by coating a graft shell comprising a copolymer of an alkyl acrylate monomer and an ethylenically unsaturated aromatic monomer with a hydrophobic surface-modified nano- By introducing a first graft shell made of silica to form a dual graft shell, it is possible not only to improve the characteristics and elongation of the lowered butadiene core, but also to make it easier to form a second graft shell . As a result, it is possible to obtain an effect of improving the transparency of the vinyl chloride resin, as well as the impact property and the projection property.

The (ii) surface-modified nanosilica constituting the first graft shell may be prepared by reacting the nanosilica with an organosilane compound in an acid and an organic solvent. That is, the surface of the nanosilica is modified to be hydrophobic by coating the entire surface of the nanosilica with an organosilane compound capable of grafted polymerization. As a result, the grafting efficiency can be improved by improving the affinity between the nanosilica and the rubber polymer, so that the effect of easily forming a shell can be obtained.

A representative example of the organosilane compound may include methacryloxypropyltrimethoxysilane.

In addition, in the surface-modified nanosilica, the mixing ratio (weight ratio) of the nanosilica: organosilane compound is preferably 1: 0.5 to 1. If the content ratio of the organosilane compound is less than 0.5, there is a disadvantage that the surface modification is not easy. If the content is more than 1, the organosilane compound shows very low water solubility and the polymerization is not easy.

It is preferable that the first grafted shell made of the surface-modified nanosilica is contained in an amount of 5 to 15% by weight. When the first graft shell is less than 5% by weight, the effect of improving the projection characteristics is insignificant. %, There is a disadvantage that the impact strength is lowered.

Also, in the present invention, an MBS-based graft copolymer capable of raising the refractive index in order to improve the transparency of the vinyl chloride resin is required. To this end, the second grafted shell (iii) comprises an alkyl acrylate- And a copolymer of an unsaturated aromatic monomer.

At this time, the content ratio of the alkyl acrylate monomer and the ethylenically unsaturated aromatic monomer is preferably 1: 1 wt%. If the content ratio of the alkyl acrylate monomer or the ethylenically unsaturated aromatic monomer is less than 1 or more than 1, compatibility of the prepared MBS-based graft copolymer of the core-shell-shell structure with the vinyl chloride resin becomes large The problem of degradation occurs.

Here, the alkyl acrylate monomer constituting the second graft shell may be exemplified by methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, a single substance selected from the group consisting of n-butyl methacrylate, benzyl methacrylate, lauryl methacrylate, stearyl methacrylate, hexyl methacrylate and 2-ethylhexyl methacrylate, or a mixture of two or more thereof .

The ethylenically unsaturated aromatic monomer constituting the second graft shell serves to suppress the light scattering caused by the refractive index difference and to maintain transparency by making the refractive index of the rubber polymer the same as that of the thermoplastic polyester resin, Representative examples thereof may include a single substance selected from the group consisting of styrene,? -Methylstyrene, p-methylstyrene, vinyltoluene and 3,4-dichlorostyrene, or a mixture of two or more thereof.

 The second grafted shell composed of the copolymer of the alkyl acrylate monomer and the ethylenically unsaturated aromatic monomer is preferably contained in an amount of 25 to 30% by weight. If the content of the second graft shell is less than 25% by weight, The reinforcing effect is insignificant. When it exceeds 30% by weight, the grafting ratio can not be sufficiently increased due to the reduction of the graft monomer, and the lack of compatibility with the rubber polymer and the thermoplastic resin causes dispersion and mechanical properties, There is a problem of deterioration.

The glass transition temperature of the MBS-based graft copolymer of the present invention is preferably -30 캜 or lower.

(B) Method for producing MBS-based graft copolymer for impact modifier having a core-shell-shell structure

In an embodiment of the present invention,

(a) preparing a butadiene-based rubber polymer core by emulsion polymerization;

(b) preparing surface-modified nanosilica;

(c) preparing a copolymer of the core-first shell structure by primary emulsion graft-polymerizing the butadiene-based rubber polymer core and the surface-modified nanosilica; And

(d) preparing a graft copolymer of a core-shell-shell structure by secondary emulsion graft-polymerizing the copolymer of the core-first shell structure, the alkyl acrylate monomer and the ethylenically unsaturated aromatic monomer, Based graft copolymer for an impact modifier.

In addition, the method of the present invention can be carried out by preparing a graft copolymer of the above-mentioned core-shell-shell structure, if necessary, by mixing the prepared MBS-based graft copolymer with an antioxidant, To separate the polymer and water, and then dehydrating and drying the polymer to prepare a powder.

(a) Production of butadiene rubber polymer core

In the method of the present invention, the step of preparing the butadiene rubber polymer core (a) is formed into an emulsion by emulsion polymerization,

0.1 to 0.5 part by weight of an emulsifier (sodium formaldehyde sulfoxylate), 0.1 to 0.5 part by weight of a polymerization initiator, 0.1 to 0.3 part by weight of ethylenediaminetetra sodium acetate, 0.1 to 0.3 part by weight and 50 to 80 parts by weight of ion-exchanged water, and performing a first polymerization reaction; And 50 to 70 parts by weight of a butadiene compound at a (a ") polymerization conversion ratio of 90%, and performing a secondary polymerization reaction.

The butadiene compound may be any conventional butadiene compound, and is not particularly limited, but specifically 1,3-butadiene may be used.

The emulsifier preferably contains about 0.1 to 0.5 parts by weight based on 100 parts by weight of the butadiene compound to be used. If the amount of the emulsifier is less than the above range, an excessive amount of solidification product is generated during polymerization, Gas may be generated at the appearance of the molded article at the time of molding.

Examples of the emulsifier include sodium formaldehyde sulfoxylate, alkylaryl sulfonate, alkaline methyl alkyl sulfonate, sulfonated alkyl ester, fatty acid soap, and alkali salts of rosin acid, potassium oleate, and the like.

The polymerization initiator is preferably used in an amount of about 0.1 to 0.5 parts by weight, specifically 0.11 part by weight based on 100 parts by weight of the butadiene compound used. Typical examples thereof include t-butyl hydroperoxide (TBHP), cumene hydroperoxide Oxide, diisopropylbenzene hydroperoxide, and oxidation-reduction catalysts such as sodium formaldehyde sulfoxylate, ethylenediaminetetra sodium acetate, ferrous sulfate, sodium pyrophosphate, and dextrose can be used.

It is preferable that pure water having a metal ion concentration of 2 ppm or less through the ion exchanger is used as the ion exchange water. The amount of the ion exchange water used is preferably 50 parts by weight or more and 80 parts by weight or less, specifically 75 parts by weight. If the amount of the ion-exchanged water to be used is less than the above range, it is difficult to adjust the reaction heat during the polymerization reaction. If the amount exceeds the above range, excessive use of the ion-exchanged water results in a low slurry content.

The emulsion polymerization process for preparing the butadiene rubber polymer core (a) is preferably carried out at about 40 to 65 ° C. Specifically, the first polymerization reaction can be carried out at a temperature of 40 to 60 占 폚, preferably 50 to 60 占 폚, for 7 to 10 hours. The secondary polymerization may be carried out at 40 to 60 캜, preferably 40 to 55 캜, for 12 to 18 hours.

(b) Preparation of surface-modified nanosilica

In addition, in the method of the present invention, the step (b) of producing the surface-modified nanosilica may include: (b ') adding nanosilica to the reaction solvent and dispersing the nanosilica; (b ") a step of adding an organosilane compound to the reaction solution in which the nanosilica is dispersed to prepare a mixed solution, and (b" ') The method comprising the steps of:

At this time, the reaction solvent is not limited as long as it is a solvent having excellent property of mixing with an organic solvent, and may specifically include toluene and the like.

The above method can be carried out by adding toluene on nitrogen, then dissolving the nanosilica with mechanical stirring and ultrasonication, and further adding the organosilane dissolved in ethanol to the mixture.

The organosilane compound may include methacryloxypropyltrimethoxysilane.

The mixing ratio of the nano-silica: organosilane compound is preferably 1: 0.5 to 1. If the content ratio of the organosilane compound is less than 0.5, there is a disadvantage that the surface modification is not easy, and when the content is more than 1, the organosilane compound exhibits very low water solubility and is not easily polymerized.

The surface modification reaction step may be carried out by stirring at 45 캜 to 55 캜 for 1 to 2 hours.

Further, the method may further include the step of cooling the mixed solution (b "") after completion of the surface modification reaction, separating the mixture using a centrifuge, and then extracting and drying.

The extraction can be performed by extracting the dried sample in a vacuum state at 90 DEG C or below with toluene. Subsequently, it can be dried again in a vacuum state at 90 DEG C or lower.

(c) Preparation of Copolymer of Core-Shell Structure

The primary emulsion graft polymerization process may include the step of charging and reacting the butadiene rubber polymer core with an emulsifier, surface modified nanosilica, and a polymerization initiator.

At this time, the mixing ratio of the butadiene rubber polymer core and the surface modified nanosilica is 55 to 65% by weight based on 100% by weight of the final graft copolymer, and the surface modified nanosilica is 5% by weight By weight to 15% by weight. That is, when the amount is exceeded or less than the above range, the impact resistance is lowered.

The emulsifier preferably comprises about 0.1 to 0.3% by weight, based on the total amount of the butadiene rubber polymer to be added, and is selected from various types well known in emulsion polymerization techniques, But preferably sodium dodecyl sulfate (SDS) or the like can be used. If the amount of the emulsifier used in each step is smaller than the above range, an excessive amount of coagulated solid is formed, which is unreasonable and causes a decrease in productivity in the process.

In addition, the polymerization initiator preferably includes about 0.5% by weight to 0.1% by weight, based on the total amount of the butadiene rubber polymer added, and the same types as those used for polymerizing the rubber polymer core may be used. At this time, when the amount of the polymerization initiator used exceeds the above range, if it is used in excess, there is a problem that the surface structure of the particles can be changed. Especially, in the shell reaction, a large amount of the polymerization initiator should be avoided.

The amount of the ion exchanged water may be about 50 to 200 parts by weight based on 100 parts by weight of the butadiene polymer core. If the amount is less than the above range, It is difficult to adjust the amount of the slurry. If the amount of the slurry exceeds the above range, the slurry content is low, which causes a reduction in productivity in the process, which is unreasonable.

The primary emulsion graft polymerization is preferably carried out at a temperature in the range of about 40 to 65 ° C, more preferably 50 to 60 ° C.

(d) Preparation of Graft Copolymer of Core-Shell-Shell Structure

In the second emulsion graft polymerization reaction (d), an emulsifier is added to a solution containing the graft copolymer of the core-shell structure in the step (c), and an alkyl acrylate monomer, an ethylenically unsaturated aromatic monomer, And then reacting the resultant mixture.

At this time, the alkyl acrylate monomer and the ethylenically unsaturated aromatic monomer are preferably contained so that the content of the second graft shell prepared based on 100 wt% of the final graft copolymer is about 25 to 30 wt% The content ratio of the alkyl acrylate monomer and the ethylenically unsaturated aromatic monomer is preferably 1: 1. That is, when the refractive index is out of the above range, the refractive index is changed and transparency is lowered.

The emulsifier preferably contains about 0.1 to 0.3% by weight, based on the total amount of the butadiene rubber polymer, and is the same as that used when the rubber polymer core is polymerized. But it is preferable to use sodium dodecyl sulfate (SDS) or the like.

In addition, the polymerization initiator preferably contains about 0.1 to 0.3% by weight based on the total content of the butadiene rubber polymer, and the same one as used for polymerizing the rubber polymer core may be used.

The second emulsion graft polymerization reaction is preferably carried out at a temperature within a range of about 40 to 65 ° C, more preferably at a temperature of 50 to 60 ° C.

On the other hand, in the present invention, the method of introducing the monomers in each step is a combination of the temporary input method and the continuous input method. For example, the core polymerization step for preparing the rubber polymer core component may be carried out by continuously reacting the monomers with a continuous feed method without making the monomers into a pre-emulsion, thereby increasing the processability. The shell polymerization step is a step in which all the monomers The grafting reaction is induced by the injection method.

As a result of the polymerization according to the method of the present invention, 100 parts by weight of the MBS-based graft copolymer, which is the same as the sum of the charged monomers, could be obtained.

The prepared MBS-based graft copolymer was stirred with an antioxidant, salt, heat and acid were added to separate the polymer and water, followed by dehydration and drying to prepare a powder

The double shell serves to impart compatibility with the thermoplastic resin to the graft copolymer and allows the rubber polymer core to exert its impact strength well. It is important to wrap the shell well so that the rubber polymer of the core is dispersed well. However, if the shell is too thick, the impact received from the outside can not be transmitted to the inner core, and the impact resistance is lowered. Therefore, the content of the rubber polymer used is preferably in the range of 55 to 65 wt.%. If the content of the rubber polymer is less than 55 wt%, the impact reinforcing effect is insignificant. If the content of the rubber polymer is more than 65 wt% The grafting ratio can not be sufficiently increased, the dispersibility in the matrix resin is lowered, and the impact strength is lowered. Further, after the polymerization is completed, aggregation and drying tend to result in agglomeration.

The MBS-based graft copolymer prepared by the above method is conventionally melted and mixed with a thermoplastic resin through an extrusion process, and is processed into a pellet form to be made into a final rubber-reinforced thermoplastic resin. In this case, the conventional thermoplastic resin Such as acrylonitrile-styrene copolymer (SAN), acrylonitrile-styrene-methyl methacrylate (MS resin), polycarbonate (PC), polybutylene terephthalate (PBT), polyvinyl chloride Resins can be used, and there is no limitation on the resin used, and when the impact resistance is required, the resin can be used freely.

In addition, these graft copolymers can be used additionally for thermoplastic resins and lubricants, heat stabilizers and other processing additives in the process of melt molding through extrusion and extrusion processes, I do not.

As described above, the MBS-based graft copolymer of the core-shell-shell structure of the present invention comprises a surface-modified nanosilica and a double grafted shell composed of the alkyl acrylate monomer and the ethylenically unsaturated aromatic monomer, The condensation reaction of methacrylic acid does not occur, gel formation can be prevented, and transparency can be maintained.

Particularly, when the MBS graft copolymer of the present invention is used as an impact modifier in the production of a vinyl chloride resin, the binding force (compatibility) with the vinyl chloride resin is improved, and the grafting efficiency is increased and the graft polymer It is possible to improve the aggregation temperature drop phenomenon caused by the increase of the rubber content in the graft polymer due to the synergistic effect of the transition temperature (Tg), and it is possible to improve the stability on the polymer polymer surface depending on the carboxylic acid group of methacrylic acid, . ≪ / RTI > Therefore, the impact strength and the coagulation temperature can be improved without impairing the transparency and processability characteristics due to the difference in refractive index during the production of the vinyl chloride resin.

Hereinafter, the present invention will be described in more detail with reference to Examples and Experimental Examples. However, the following examples and experimental examples are provided to illustrate the present invention and are not intended to limit the scope of the present invention.

Example

(Example 1)

(a) a step of producing a butadiene-based rubber polymer

To a 120 L high-pressure polymerization vessel equipped with a stirrer, 30 parts by weight of 1,3-butadiene, 0.1 part by weight of sodium formaldehyde sulfoxylate, 0.11 part by weight of t-butyl hydroperoxide, 0.2147 part by weight of ethylenediaminetetra sodium acetate, 0.293 parts by weight of iron, and 75 parts by weight of ion-exchanged water, and then polymerization was carried out in one step at 40 ° C for 7 hours. The degree of polymerization conversion in the first step was 90%. After the first stage polymerization, 70 parts by weight of butadiene was added, and the mixture was polymerized in two stages at 55 DEG C for 12 hours to prepare a butadiene rubber polymer having a particle size of 0.1 mu m and a gel content of 70%.

(b) Step of preparing surface-modified nanosilica

In a 120 ml reactor equipped with a stirrer, 4 g of nano silica was stirred with toluene and dispersed through sonication.

Subsequently, 2 g of methacryloxypropyltrimethoxysilane (nano silica: organosilane weight ratio 1: 0.5) was dissolved in 10 ml of ethanol, and the solution was introduced into a flask containing nano silica, and reacted at 50 ° C. for 1 hour Then, it was cooled to room temperature.

Then, the phases were separated using a centrifugal separator, and then dried at 90 DEG C under vacuum. The mixture was extracted with toluene and then dried at 90 DEG C under vacuum for 24 hours.

(c) primary graft polymerization process

A stirrer, a thermometer, a nitrogen inlet, and a circulating condenser, was charged with 120 parts by weight of deionized water (DDI water), 120 parts by weight of a butadiene rubber polymer core prepared in the step (a) 65 wt% of the final MBS-based graft copolymer was charged into a closed polymerization reactor and charged with nitrogen. Then, 0.3 wt% of an emulsifier (SDS) was added thereto, and then, in step (b) 5% by weight of the prepared surface-modified nanosilica (based on the final MBS-based graft copolymer content) was added and then nitrogen was injected for 20 minutes.

0.1% by weight of t-butyl hydroperoxide as a polymerization initiator was added to the reaction solution, and the reaction was allowed to proceed for 2 hours.

(d) Second graft polymerization process

0.2 wt% of an emulsifier (ethylenediaminetetra sodium acetate) was added to the primary graft polymer solution prepared in the step (c), nitrogen was injected for 20 minutes, and methyl methacrylate (MMA) and styrene The monomer (SM) was added in an amount of 15% (based on the final MBS-based graft copolymer content). Subsequently, 0.1 wt% of t-butyl hydroperoxide as a polymerization initiator was added to the reaction solution, and the reaction was carried out for 3 hours.

(e) Preparation of graft copolymer powder

0.5 parts by weight of an antioxidant (Irganox-245) was added to 100 parts by weight of the rubbery graft copolymer prepared in the step (d), and the mixture was agitated with an aqueous sulfuric acid solution while stirring. Followed by dehydration and drying to obtain a graft copolymer powder. The physical properties of the resulting graft copolymer powder were evaluated and are shown in Table 1 below. At this time, the glass transition temperature of the graft rubber polymer was -35 占 폚.

[Example 2]

(C) 55% by weight of a butadiene rubber polymer core (based on the final MBS-based graft copolymer content), surface modified nanosilica in the first graft polymerization step, The graft copolymer powder was obtained in the same manner as in Example 1, except that 15 wt% of the final graft copolymer (based on the final MBS-based graft copolymer content) was added. The physical properties of the resulting graft copolymer powder were evaluated and are shown in Table 1 below. At this time, the glass transition temperature of the graft rubber polymer was -35 占 폚.

[Example 3]

(C) 60% by weight of a butadiene rubber polymer core (based on the final MBS-based graft copolymer content), 5% by weight of surface modified nanosilica in the first graft polymerization step, Graft copolymer powder was obtained in the same manner as in Example 1, except that 10 weight% of the final graft copolymer (based on the final MBS-based graft copolymer content) was added. The physical properties of the resulting graft copolymer powder were evaluated and are shown in Table 1 below. At this time, the glass transition temperature of the graft rubber polymer was -35 占 폚.

[Example 4]

The procedure of Example 1 was repeated except that 4 g of methacryloxypropyltrimethoxysilane was used in the preparation of the surface-modified nanosilica in the step (b) of preparing the surface-modified nanosilica, and the ratio of the nanosilica: organosilane was 1: 1, a graft copolymer powder was obtained in the same manner as in Example 1. The results are shown in Table 1. < tb > < TABLE > The physical properties of the resulting graft copolymer powder were evaluated and are shown in Table 1 below. At this time, the glass transition temperature of the graft rubber polymer was -35 占 폚.

[Comparative Example 1]

(C) 79% by weight of the butadiene rubber polymer core (based on the final MBS-based graft copolymer content), the surface-modified nanosilica in the first graft polymerization step, (Based on the final MBS-based graft copolymer content) of 1 wt% (nano silica: organosilane weight ratio 0.5: 1), (d) methyl methacrylate (MMA) in the second graft polymerization step, And styrene monomer (SM) were added in an amount of 10 wt%, respectively, to obtain a graft copolymer powder. The physical properties of the resulting graft copolymer powder were evaluated and are shown in Table 1 below.

[Comparative Example 2]

The procedure of Example 1 was repeated except that the surface-modified nanosilica was not included ((c) the first graft polymerization step was omitted), (d) the butadiene rubber polymer core was added to the second graft polymerization step Graft copolymer was added in an amount of 70% by weight based on the final MBS-based graft copolymer content, to obtain a graft copolymer powder having a core-shell structure. The physical properties of the resulting graft copolymer powder were evaluated and are shown in Table 1 below.

[Comparative Example 3]

(C) 50% by weight of the butadiene rubber polymer core (based on the final MBS-based graft copolymer content), the surface-modified nanosilica in the first graft polymerization step, (Based on the final MBS-based graft copolymer content) was added in an amount of 20% by weight based on the total amount of the graft copolymer. The physical properties of the resulting graft copolymer powder were evaluated and are shown in Table 1 below.

[Comparative Example 4]

(C) 35% by weight of a butadiene rubber polymer core (based on the final MBS-based graft copolymer content), a surface modified nanosilica in the first graft polymerization step, (Based on the final MBS-based graft copolymer content) was added in an amount of 35% by weight based on the total amount of the graft copolymer. The physical properties of the resulting graft copolymer powder were evaluated and are shown in Table 1 below.

[Comparative Example 5]

(C) 40% by weight of a butadiene rubber polymer core (based on the final MBS-based graft copolymer content), a surface modified nanosilica in the first graft polymerization step, (MMA) and styrene monomer (SM) were added in an amount of 10% by weight in the second graft polymerization step, (d) 40% by weight of methyl methacrylate (based on the final MBS-based graft copolymer content) The graft copolymer powder was obtained in the same manner as in Example 1, The physical properties of the resulting graft copolymer powder were evaluated and are shown in Table 1 below.

[Comparative Example 6]

(c) In the first graft polymerization step, the butadiene rubber polymer core was mixed with 79 wt% of the final MBS-based graft copolymer, 5 wt% of the surface-modified nanosilica (nano silica: organosilane weight ratio 1: 1.2) Except that 10 wt% of methyl methacrylate (MMA) and styrene monomer (SM) were added in the second graft polymerization step (d), respectively, in the same manner as in Example 1, Copolymer powder was obtained. The physical properties of the resulting graft copolymer powder were evaluated and are shown in Table 1 below.

Experimental Example

Experimental Example  One

, 0.5 parts by weight of an external lubricant (paraffin wax), 0.5 parts by weight of a processing aid (LG Chem, PA-910), 0.5 parts by weight of an antioxidant, And 0.3 parts by weight of a pigment were thoroughly mixed at a temperature of 130 캜 using a high-speed stirrer to prepare a masterbatch of vinyl chloride resin masterbatch. Then, in the above vinyl chloride resin masterbatch, in Examples 1 to 4 and Comparative Examples 1 to 6 7 parts by weight of each of the prepared MBS-based graft copolymer powder was injected and injected at a temperature of 200 ° C to prepare a sample for physical property evaluation. The physical properties of the sample were shown in Table 1.

Evaluation of Izod Impact Strength: The sheets prepared in Examples 1 to 4 and Comparative Examples 1 to 6 were cut to prepare specimens having a thickness of 0.5 mm and 10 cm x 14 cm (ASTM D-256 standard) and aged at 25 ° C for 2 hours After rotating the circular saw blade, the rpm was measured at 50% cracking of the specimen when it was applied to the saw blade at a speed of 15 mm / sec. The obtained results are summarized in Table 1 below.

* Projection characteristics: After 170-degree roll-mill processing, the projections counted on a certain area were compared and evaluated (out of 5 points). In this case, the case where the number of projections is low and the surface state is excellent is represented by 5, and the closer to 1 the surface condition is, the closer it is to 1.

* Elongation Evaluation: The samples processed for the dendritic layering were prepared as elongation evaluation samples using an extruder and evaluated using a tensile machine. Due to the program in the measuring device, it is represented numerically and the numerical value is expressed in proportion to the length of the existing specimen. At this time, the higher the numerical value, the better the physical properties.

As shown in Table 1, it was confirmed that when the composition and structure of the butadiene impact modifier were changed, the physical properties of the vinyl chloride resin were improved. Specifically, in the case of the impact modifiers (Examples 1 to 4) including the graft shell made of the surface-modified nanosilica according to the present invention, it was confirmed that the impact strength was all 11 or more and the elongation was evenly improved to 220 or more I could. It is also understood that the protruding property (5 out of 5 points) is 5 and the surface state is excellent.

On the other hand, in the case of Comparative Example 1 in which the content of the surface-modified nanosilica is 5 wt% or less and the content of the alkyl acrylate monomer and ethylenically unsaturated aromatic monomer constituting the second shell is 20 wt% or less, the impact strength is 10, The elongation was 205 and the projection property was 3, indicating that the physical properties were all low.

In addition, in Comparative Example 2, which does not include the surface-modified nanosilica, and Comparative Example 4, in which the surface-modified nanosilica content is higher than 35% by weight, the impact strength, elongation, and projection characteristics are all lower.

In the case of Comparative Example 3, it was confirmed that the elongation was increased, but the projection characteristic was low. The protrusion characteristics have a great influence on the workability. That is, if the elongation is high but the projection characteristic is low, the physical properties of the processed sample of the end user may be affected.

In the case of Comparative Example 5 in which the content of the surface-modified nanosilica was 40% by weight or more and the content of the second shell was reduced to 20% by weight or less, the compatibility with the vinyl chloride resin was lowered and the impact strength and tensile strength characteristics Which is the most deteriorated.

On the other hand, in the case of Comparative Example 6, since the content ratio of the organosilane compound in the surface-modified nanosilica exceeded 1 and showed extremely low water solubility, the polymerization for forming the shell was not easy, there was.

Claims (21)

Butadiene-based rubber polymer core;
A double graft shell coated on the surface of the rubber polymer core,
The double grafted shell
A first graft shell consisting of nanosilica coated on the surface of the rubber polymer core and surface modified; And
A second grafted shell coated on the surface of the first graft shell and consisting of a copolymer of an alkyl acrylate monomer and an ethylenically unsaturated aromatic monomer; and a second grafted shell coated on the surface of the first grafted shell and comprising a methyl methacrylate-butadiene-styrene graft for an impact modifier As a copolymer,
The graft copolymer
55 to 65 wt% of the butadiene-based rubber polymer core;
5 to 15% by weight of the first graft shell; And
And 25 to 30% by weight of the second graft shell; and a methyl methacrylate-butadiene-styrene graft copolymer.
delete The method according to claim 1,
Wherein the surface-modified nanosilica is an organosilane compound graft-polymerizable on the entire surface of the nanosilica.
The method according to claim 1,
Methylmethacrylate-butadiene-styrene graft copolymer wherein the surface-modified nanosilica surface is hydrophobic.
The method according to claim 1,
Wherein the surface-modified nanosilica is prepared by reacting nanosilica with an organosilane compound in an acid and an organic solvent.
The method of claim 5,
Methyl methacrylate-butadiene-styrene graft copolymer wherein the organosilane compound comprises methacryloxypropyltrimethoxysilane.
The method of claim 5,
Wherein the weight ratio of the nano-silica to the organosilane compound is 1: 0.5 to 1. 2. The methyl methacrylate-butadiene-styrene graft copolymer according to claim 1,
The method according to claim 1,
Methyl methacrylate-butadiene-styrene graft copolymer wherein the weight ratio of the alkyl acrylate monomer and the ethylenically unsaturated aromatic monomer in the second graft shell is 1: 1.
The method of claim 8,
Wherein the alkyl acrylate monomer is selected from the group consisting of methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, n-butyl methacrylate, Butadiene-styrene-based graft copolymer, which is a single substance selected from the group consisting of acrylic acid, methacrylic acid, lauryl methacrylate, stearyl methacrylate, hexyl methacrylate and 2-ethylhexyl methacrylate, or a mixture of two or more thereof Copolymer.
The method of claim 8,
Wherein the ethylenically unsaturated aromatic monomer is a single substance selected from the group consisting of styrene,? -Methylstyrene, p-methylstyrene, vinyltoluene and 3,4-dichlorostyrene, or a mixture of two or more thereof. - styrene-based graft copolymer.
The method according to claim 1,
Wherein the methyl methacrylate-butadiene-styrene graft copolymer has a glass transition temperature of -30 占 폚 or lower.
(a) preparing a butadiene-based rubber polymer core by emulsion polymerization;
(b) preparing surface-modified nanosilica;
(c) preparing a copolymer of the butadiene-based rubber polymer core and the core-shell structure by first emulsion graft-polymerizing the surface-modified nanosilica; And
(d) preparing a graft copolymer of a core-shell-shell structure by secondary emulsion graft-polymerizing a copolymer of the core-shell structure prepared above with an alkyl acrylate monomer and an ethylenically unsaturated aromatic monomer, By weight based on the total weight of the graft copolymer.
The method of claim 12,
The step of (a) preparing the butadiene rubber polymer core comprises
(a ') conducting a first polymerization reaction by collectively administering a butadiene compound, an emulsifier, a polymerization initiator, ethylenediaminetetra sodium acetate, ferrous sulfate, and ion exchange water; And
butadiene-styrene graft copolymer, wherein the step (a ") further comprises adding a butadiene compound at a polymerization conversion rate of 90% to carry out a secondary polymerization reaction.
14. The method of claim 13,
Wherein the butadiene compound is 1,3-butadiene. 2. A process for producing a methyl methacrylate-butadiene-styrene graft copolymer according to claim 1, wherein the butadiene compound is 1,3-butadiene.
The method of claim 12,
Wherein the emulsion polymerization process for producing the butadiene rubber polymer core (a) is carried out at a temperature in the range of 40 占 폚 to 65 占 폚.
The method of claim 12,
The step (b) of producing the surface-modified nanosilica comprises
(b ') adding nanosilica to the reaction solvent and dispersing the mixture;
(b ") adding an organosilane compound to the reaction solution in which the nanosilica is dispersed to prepare a mixed solution; and
(b "') a step of performing the surface modification reaction while stirring the mixed solution at 40 ° C to 60 ° C.
18. The method of claim 16,
Wherein the organosilane compound comprises methacryloxypropyltrimethoxysilane. 2. The method according to claim 1, wherein the organosilane compound is methacryloxypropyltrimethoxysilane.
18. The method of claim 16,
Wherein the weight ratio of the nano-silica to the organosilane compound is 1: 0.5 to 1.
18. The method of claim 16,
Said method further comprising, after completion of the surface modification reaction, (b ") cooling said mixed solution and then separating, extracting and drying said methyl methacrylate-butadiene-styrene graft copolymer Gt;
The method of claim 12,
Wherein the primary emulsion graft polymerization is carried out at a temperature in the range of 40 占 폚 to 65 占 폚.
The method of claim 12,
Wherein the second emulsion graft polymerization is carried out at a temperature in the range of 40 占 폚 to 65 占 폚.