阅读说明：本技术 接枝共聚物的制备方法和由此制备的接枝共聚物 (Method for preparing graft copolymer and graft copolymer prepared thereby ) 是由 徐在范 李大雨 朴晶台 金圭善 张志旭 于 2018-10-26 设计创作，主要内容包括：本发明提供一种接枝共聚物的制备方法和由此制备的接枝共聚物,所述制备方法包括：制备反应溶液,该反应溶液包含含有来自二烯类单体的单元和来自烯烃类单体的单元的共聚物、芳香族乙烯基类单体、乙烯基氰基类单体和反应溶剂；以及添加所述反应溶液以在100℃至110℃下进行第一本体聚合,其中,所述共聚物包含5重量％至10重量％的所述来自二烯类单体的单元,所述接枝共聚物的橡胶平均粒径为2μm至5μm。(The present invention provides a method for preparing a graft copolymer, the method comprising: preparing a reaction solution containing a copolymer containing a unit derived from a diene monomer and a unit derived from an olefin monomer, an aromatic vinyl monomer, a vinyl cyano monomer, and a reaction solvent; and adding the reaction solution to perform a first bulk polymerization at 100 ℃ to 110 ℃, wherein the copolymer comprises 5 wt% to 10 wt% of the units derived from the diene-based monomer, and the graft copolymer has a rubber average particle diameter of 2 μm to 5 μm.)

1. A method of making a graft copolymer comprising:

preparing a reaction solution comprising: a copolymer comprising a unit derived from a diene monomer and a unit derived from an olefin monomer, an aromatic vinyl monomer, a vinyl cyano monomer, and a reaction solvent; and

adding the reaction solution to perform a first bulk polymerization at 100 ℃ to 110 ℃,

wherein the copolymer comprises 5 to 10% by weight of the units derived from diene monomers,

the graft copolymer has a rubber average particle diameter of 2 to 5 μm.

2. The production method according to claim 1, wherein the graft copolymer has a rubber average particle diameter of 2.5 to 4.5 μm.

3. The production method according to claim 1, wherein the graft copolymer has a degree of grafting of 35 to 60%.

4. The production method according to claim 1, wherein the graft copolymer has a degree of grafting of 40 to 55%.

5. The production method according to claim 1, wherein the first bulk polymerization is performed by first bulk polymerizing the reaction solution at 100 ℃ to 110 ℃ while stirring at 50rpm to 90 rpm.

6. The production method according to claim 1, wherein the unit derived from a diene-based monomer comprises a unit derived from ethylidene norbornene.

7. The production method according to claim 1, wherein the units derived from an olefin-based monomer include units derived from ethylene and units derived from propylene.

8. The production method according to claim 1, wherein the mooney viscosity of the copolymer at ML (1+4) at 100 ℃ is 30 to 80.

9. The production method according to claim 1, wherein the weight average molecular weight of the copolymer is 110,000 to 250,000 g/mol.

10. The preparation process according to claim 1, wherein the reaction solution comprises, with respect to its total weight:

3 to 15 weight percent of the copolymer;

40 to 65 wt% of the aromatic vinyl monomer;

5 to 25 weight percent of the vinyl cyano-based monomer; and

as the balance of the reaction solvent.

11. The production method according to claim 1, wherein in the first bulk polymerization, an initiator and a molecular weight controlling agent are further added.

12. The production method according to claim 11, wherein, with respect to 100 parts by weight of the reaction solution, further added are:

0.02 to 0.2 parts by weight of the initiator; and

0.02 to 0.9 parts by weight of the molecular weight controlling agent.

13. The method of manufacturing according to claim 1, further comprising: after the first bulk polymerization, subjecting the reaction solution subjected to the first bulk polymerization to a second bulk polymerization at 130 ℃ to 150 ℃.

14. The production method according to claim 13, wherein the second bulk polymerization is carried out by second bulk polymerizing the reaction solution subjected to the first bulk polymerization at 130 ℃ to 150 ℃ while stirring at 30rpm to 70 rpm.

15. A graft copolymer prepared by the preparation method of any one of claims 1 to 14 and having a gloss of 22% or less measured according to ASTM 1003.

Technical Field

[ Cross-reference to related applications ]

The present application claims priority and benefit from korean patent application No.10-2017-0144958, filed on 11/01/2017, the disclosure of which is incorporated in its entirety by reference into the present specification.

Background

ABS graft copolymers prepared by graft polymerization of conjugated diene polymers with aromatic vinyl monomers and vinyl cyano monomers have been used in various fields due to their excellent strength, heat resistance, and molding processability. However, such ABS graft copolymer has a disadvantage in that weather resistance is lowered since hydrogen atoms of methyl groups adjacent to double bonds remaining in the molecule generated from the conjugated diene-based polymer serve as a starting point of oxidation by the action of light or oxygen to induce main chain reaction. In particular, this disadvantage causes not only whitening or cracking of the surface of the copolymer but also deterioration of various properties of a thermoplastic resin molded article comprising the graft copolymer. In order to prepare a copolymer having balanced properties by imparting weather resistance while maintaining excellent properties of the graft copolymer, conventional methods such as addition of UV stabilizers, coating, electroplating, and the like are employed. However, these methods do not substantially improve performance.

Therefore, various graft copolymers using a rubber having an unsaturated bond instead of a conjugated diene-based polymer causing deterioration of the graft copolymer have been developed, and an AES graft copolymer prepared using an ethylene-propylene copolymer is one of the developed graft copolymers. The AES graft copolymer is a graft copolymer containing substantially no unsaturated bond in the main chain, and is obtained by graft polymerization of an ethylene-propylene copolymer or an ethylene-propylene-diene terpolymer as a rubber component with styrene, acrylonitrile, or the like. The AES copolymer is known to have remarkable resistance to ultraviolet rays, oxygen and ozone and to be able to realize matte characteristics, compared with the ABS copolymer prepared using the conjugated diene-based rubber.

However, since ethylene-propylene-based rubbers and ethylene-propylene-diene-based terpolymers have few reactive moieties compared to butadiene-based rubbers, their graft polymerization with styrene and acrylonitrile is not easy to perform, often resulting in the formation of simple mixtures of rubber polymers and SAN copolymers. Therefore, when the AES graft copolymer thus obtained is subjected to injection molding, there are disadvantages such as surface contamination, reduction in impact strength, and the like, and in a serious case, a phenomenon that the injection surface is peeled off also occurs.

Therefore, improvement of the properties of AES graft copolymer is being continuously studied.

Disclosure of Invention

Technical problem

The present invention aims to provide a graft copolymer having an excellent injection surface while realizing matte characteristics, and a method for preparing the same.

Technical scheme

According to an embodiment of the present invention, there is provided a method for preparing a graft copolymer, the method comprising: preparing a reaction solution containing a copolymer containing a unit derived from a diene monomer and a unit derived from an olefin monomer, an aromatic vinyl monomer, a vinyl cyano monomer, and a reaction solvent; and adding the reaction solution to perform a first bulk polymerization at 100 ℃ to 110 ℃, wherein the copolymer comprises 5 wt% to 10 wt% of the units derived from the diene-based monomer, and the graft copolymer has a rubber average particle diameter of 2 μm to 5 μm.

In addition, according to another embodiment of the present invention, there is provided a graft copolymer prepared by the above preparation method, which has a gloss of 22% or less measured according to ASTM 1003.

Advantageous effects

The graft copolymer according to the present invention can realize matte characteristics and exhibit remarkably excellent injection surface characteristics due to its excellent degree of grafting.

Detailed Description

Hereinafter, the present invention will be described in more detail.

The terms and words used in the present specification and claims should not be construed as limited to general meanings or dictionary-defined meanings, and should be construed as meanings and principles consistent with the technical scope of the present invention on the basis of the principle that the inventor has appropriately defined the concept of the term to describe the invention in the best way.

In the present invention, the rubber average particle diameter of the graft copolymer may be defined as a particle diameter corresponding to cumulative 50 th percentile in a volume-based particle diameter distribution curve.

In the present invention, the rubber average particle diameter of the graft copolymer may be measured after dissolving a predetermined amount of the graft copolymer in a solvent. Specifically, the rubber average particle diameter of the graft copolymer can be measured using a Coulter counter (trade name: LS230, manufactured by Beckman Coulter Inc.) after 0.5g of the graft copolymer is dissolved in 100ml of methyl ethyl ketone.

In the present invention, the degree of grafting can be calculated by adding a predetermined amount of the graft copolymer to a solvent, followed by dissolution using a shaker, centrifugal separation using a centrifuge, and drying to obtain insoluble matter, and then using the insoluble matter and the following equation.

Specifically, the degree of grafting may be a predetermined amount of graft copolymer added to acetone; the graft copolymer dissociated by vibration was dissolved using a vibrator (trade name: SI-600R, manufactured by Lab.company) for 24 hours; the resulting solution was centrifuged at 14,000rpm for 1 hour using a centrifuge; and dried for 2 hours using a vacuum dryer (trade name: DRV320DB, manufactured by Advantec) at 140 deg.C to obtain insoluble, and then calculated using the insoluble and the following equation.

Degree of grafting (%) - (Y- (X × R))/(X × R) ] × 100

Y: weight of insoluble matter

X: weight of graft copolymer added to obtain insoluble matter

R: fraction of copolymer in the graft copolymer added in the case of obtaining insolubles

In the present invention, the Mooney viscosity (ML (1+4), 100 ℃) of the copolymer can be measured according to ASTM D1646.

In the present invention, the weight average molecular weight of the copolymer can be measured as a relative value with respect to a standard sample polystyrene by Gel Permeation Chromatography (GPC) using tetrahydrofuran as an elution solvent.

In the present invention, after the graft copolymer is injected to prepare a test specimen having a thickness of 3mm, the gloss can be measured according to ASTM 1003.

1. Process for preparing graft copolymers

The method for preparing a graft copolymer according to one embodiment of the present invention comprises: 1) preparing a reaction solution containing a copolymer containing a unit derived from a diene monomer and a unit derived from an olefin monomer, an aromatic vinyl monomer, a vinyl cyano monomer, and a reaction solvent; and 2) adding the reaction solution to perform a first bulk polymerization at 100 ℃ to 110 ℃, wherein the copolymer comprises 5 wt% to 10 wt% of the units derived from the diene-based monomer, and the graft copolymer has a rubber average particle diameter of 2 μm to 5 μm.

The preparation method of the graft copolymer according to one embodiment of the present invention may further include, after the first bulk polymerization, 3) performing a second bulk polymerization.

The preparation method of the graft copolymer according to one embodiment of the present invention may further include, after the second bulk polymerization, 4) recovering the unreacted monomer and the reaction solvent.

Hereinafter, each step of the preparation method of the graft copolymer according to one embodiment of the present invention will be described in detail.

1) Step of preparing reaction solution

First, a reaction solution is prepared, the reaction solution containing a copolymer containing a unit derived from a diene monomer and a unit derived from an olefin monomer, an aromatic vinyl monomer, a vinyl cyano monomer, and a reaction solvent.

The unit derived from the diene-based monomer may be a unit derived from one or more selected from dicyclopentadiene, ethylidene norbornene and vinyl norbornene, and, specifically, a unit derived from ethylidene norbornene is preferable.

The content of the units derived from diene-based monomers is from 5% to 10% by weight, preferably from 5% to 8% by weight, relative to the total weight of the copolymer.

The content of said units derived from olefinic monomers ranges from 90% to 95% by weight, preferably from 92% to 95% by weight, relative to the total weight of the copolymer.

When the content of the unit derived from the diene-based monomer and the unit derived from the vinyl-based monomer falls within the above range, graft polymerization with the aromatic vinyl-based monomer and the vinyl cyano-based monomer can be facilitated and is economical. Further, a synergistic effect is achieved due to the combination of the temperature of the first bulk polymerization and the content of the unit derived from the diene-based monomer described below, whereby the rubber average particle diameter of the graft copolymer can be appropriately obtained, and a graft copolymer having excellent matte characteristics and an excellent injection surface can be produced.

When the content of the unit derived from the diene-based monomer is less than the above range, graft polymerization cannot be sufficiently performed, and therefore, rubber particles of the graft copolymer are not uniformly formed. Therefore, the rubber average particle diameter thereof is even increased, and the connection between the copolymer-derived unit and the unit derived from the aromatic vinyl-based monomer or the unit derived from the vinyl cyano-based monomer becomes loose, causing a poor injection surface. When the content of the unit derived from the diene-based monomer is more than the above range, the production cost is significantly increased.

The units derived from olefinic monomers may be units derived from olefinic monomers of 2 to 4 carbon atoms.

The copolymer preferably comprises at least two types of units derived from olefinic monomers, more preferably comprises units derived from ethylene and units derived from propylene.

The units derived from ethylene may be included in an amount of 52 to 73 wt%, 55 to 70 wt%, 58 to 67 wt%, or 60 to 65 wt%, and preferably in an amount of 60 to 65 wt%, relative to the total weight of the copolymer.

When the content of the unit derived from ethylene falls within the above range, the properties of the graft copolymer as a final product are obtained in balance.

The units derived from propylene may be included in an amount of 20 to 40 wt%, 22 to 37 wt%, 25 to 35 wt%, or 27 to 32 wt%, and preferably in an amount of 27 to 32 wt%, relative to the total weight of the copolymer.

When the content of the unit derived from propylene falls within the above range, the properties of the graft copolymer as a final product are obtained in a balanced manner.

The mooney viscosity (ML (1+4), 100 ℃) of the copolymer may be 30 to 80 or 50 to 80, and the mooney viscosity is preferably 50 to 80.

When the mooney viscosity of the copolymer falls within the above range, a synergistic effect is achieved due to the combination of the temperature of the first bulk polymerization described below and the content of the unit derived from the diene-based monomer in the copolymer, and thereby, an appropriate average particle diameter of the copolymer-derived unit can be achieved, so that a graft copolymer having excellent matte characteristics and an excellent injection surface can be prepared.

The copolymer may have a weight average molecular weight of 110,000 to 250,000g/mol, 130,000 to 230,000g/mol, 150,000 to 210,000g/mol, or 170,000 to 190,000g/mol, and preferably has a weight average molecular weight of 170,000 to 190,000 g/mol.

When the weight average molecular weight of the copolymer falls within the above range, mechanical properties such as impact strength and the like can be excellent and an appropriate viscosity can be obtained, and thus, the process can be easily operated.

The copolymer may be included in an amount of 3 to 15 wt%, 5 to 12 wt%, or 7 to 10 wt%, and preferably in an amount of 7 to 10 wt%, with respect to the total weight of the reaction solution.

When the content of the copolymer falls within the above range, a graft copolymer which can obtain matte properties while achieving excellent weather resistance and has an excellent injection surface can be prepared.

The aromatic vinyl monomer may be one or more selected from styrene, α -methylstyrene, α -ethylstyrene, p-methylstyrene and 2, 4-dimethylstyrene, and particularly, styrene is preferable.

The aromatic vinyl monomer may be included in an amount of 40 to 65 wt%, 45 to 60 wt%, or 50 to 55 wt%, and preferably 50 to 55 wt%, with respect to the total weight of the reaction solution.

When the content of the aromatic vinyl-based monomer falls within the above range, a graft copolymer that can obtain matte properties while achieving excellent weather resistance and has an excellent injection surface can be prepared.

The vinyl cyanide-based monomer may be one or more selected from acrylonitrile, methacrylonitrile, ethacrylonitrile, phenylacrylonitrile, and α -chloroacrylonitrile, and particularly, acrylonitrile is preferred.

The vinyl cyanide-based monomer may be included in an amount of 5 to 25 wt%, 8 to 20 wt%, or 10 to 15 wt%, and preferably 10 to 15 wt%, with respect to the total weight of the reaction solution.

When the content of the vinyl cyanide-based monomer falls within the above range, a graft copolymer that can obtain matte characteristics while achieving excellent weather resistance and has an excellent injection surface can be prepared.

The reaction solvent may be one or more selected from the group consisting of toluene, ethylbenzene, xylene, and methyl ethyl ketone, and particularly, ethylbenzene is preferable.

The reaction solvent may be included as the balance so that the total content of the components of the reaction solution is 100% by weight. Due to the reaction solvent, the reaction solution can have an appropriate viscosity, the bulk polymerization described below can be promoted, and the amount of unreacted monomers and the like contained in the final product can be reduced.

2) Step of performing a first bulk polymerization

Subsequently, a first bulk polymerization of the reaction solution is carried out at 100 ℃ to 110 ℃.

The first bulk polymerization is a phase conversion step of the copolymer, the aromatic vinyl-based monomer and the vinyl cyanide-based monomer, and when the first bulk polymerization is performed at the above temperature, the phase conversion rate is increased. Further, a synergistic effect is achieved due to the combination of the temperature of the first bulk polymerization and the content of the unit derived from the diene-based monomer in the copolymer, whereby graft polymerization with the aromatic vinyl-based monomer and the vinyl cyano-based monomer can be promoted. Further, a graft copolymer having an appropriate rubber average particle diameter and an appropriate degree of grafting can be prepared, and a graft copolymer excellent not only in matte property but also in injection surface property can also be prepared.

When the temperature of the first bulk polymerization is lower than the above range, the phase conversion rate decreases. When the temperature of the first bulk polymerization is higher than the above range, the reaction rate of the graft polymerization is decreased, and therefore, the average rubber particle diameter is excessively increased, and a poor injection surface is exhibited.

The first bulk polymerization may be performed for 0.5 to 4 hours, 1.0 to 3.5 hours, 1.5 to 3.0 hours, or 1.5 to 2.5 hours, and is preferably performed for 1.5 to 2.5 hours.

When the duration of the first bulk polymerization falls within the above range, the phase conversion rate may be further improved.

The first bulk polymerization may be performed while stirring the reaction solution at 50 to 90rpm, 55 to 85rpm, 60 to 80rpm, or 65 to 75rpm, and preferably is performed while stirring at 65 to 75 rpm.

When the stirring speed falls within the above range, the matte property can be further improved.

In the first bulk polymerization, an initiator and a molecular weight controlling agent may also be added.

The initiator may be a free radical polymerization initiator having a 1 hour half-life temperature of 90 ℃ to 110 ℃. The initiator may be one or more selected from stearoyl peroxide, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, t-butylperoxy isobutyrate, and 1, 1-di (t-butylperoxy) -3,5, 5-trimethylcyclohexane, and, specifically, t-butylperoxy-2-ethylhexanoate is preferable.

The initiator may be added in an amount of 0.01 to 0.2 parts by weight, 0.02 to 0.1 parts by weight, 0.02 to 0.08 parts by weight, or 0.02 to 0.06 parts by weight, and preferably in an amount of 0.02 to 0.06 parts by weight, relative to 100 parts by weight of the reaction solution. When the addition amount of the initiator falls within the above range, graft polymerization can be easily performed, and polymer-derived units can be easily formed.

The molecular weight controlling agent may be one or more selected from t-dodecyl mercaptan and n-octyl mercaptan, and particularly, t-dodecyl mercaptan is preferable.

The molecular weight controlling agent may be added in an amount of 0.02 to 0.9 parts by weight, 0.02 to 0.8 parts by weight, or 0.03 to 0.7 parts by weight, and preferably in an amount of 0.03 to 0.7 parts by weight, relative to 100 parts by weight of the reaction solution.

When the amount of the molecular weight control agent added falls within the above range, not only graft polymerization can be easily performed, but also the copolymer derived units can have an appropriate average particle diameter. In addition, a graft copolymer having more excellent impact strength can be prepared.

The first bulk polymerization may be a continuous bulk polymerization which is performed by continuously adding the reaction solution, the initiator and the molecular weight controlling agent at a predetermined rate.

3) Step of conducting second bulk polymerization

Subsequently, the reaction solution subjected to the first bulk polymerization may also be subjected to a second bulk polymerization at 130 ℃ to 150 ℃.

The second bulk polymerization is performed to increase the polymerization conversion rate, and when the second bulk polymerization is performed at the above temperature, the polymerization conversion rate may be further increased.

The second bulk polymerization may be carried out in a different reactor than the reactor used for the first bulk polymerization. The reactors for the first bulk polymerization and the second bulk polymerization may be continuous reactors connected in series. The reactor for the second bulk polymerization may be a continuous reactor in which three or more reactors are connected in series.

The second bulk polymerization may be carried out while gradually increasing the temperature in the range of 130 ℃ to 150 ℃. In order to change the polymerization temperature, bulk polymerization may be performed after transferring the reaction solution to another reactor.

In addition, the second bulk polymerization may be performed by continuously adding the reaction solution.

The second bulk polymerization may be performed while stirring the reaction solution at 30 to 70rpm, 35 to 65rpm, 40 to 60rpm, or 45 to 55rpm, and preferably while stirring at 45 to 55 rpm.

When the stirring speed falls within the above range, the matte property can be further improved.

In the second bulk polymerization, a molecular weight controlling agent may also be added. The type of molecular weight controlling agent is the same as described above.

The molecular weight controlling agent may be added in an amount of 0.02 to 0.9 parts by weight, 0.02 to 0.8 parts by weight, or 0.03 to 0.7 parts by weight, and preferably in an amount of 0.03 to 0.7 parts by weight, relative to 100 parts by weight of the reaction solution.

When the amount of the molecular weight control agent added falls within the above range, not only graft polymerization can be easily performed, but also the copolymer derived units can have an appropriate average particle diameter. In addition, a graft copolymer having more excellent impact strength can be prepared.

4) Step of recovering unreacted monomer and reaction solvent

Subsequently, a step of recovering the unreacted monomer and the reaction solvent may also be performed.

The step of recovering unreacted monomer and reaction solvent may be performed in a devolatilizer. A devolatilizer equipped with a heat exchanger can maintain a vacuum at a temperature of 220 ℃ to 250 ℃ and a pressure of less than 25 torr, a temperature of 225 ℃ to 245 ℃ and a pressure of less than 20 torr, or a temperature of 230 ℃ to 240 ℃ and a pressure of less than 16 torr, preferably at a temperature of 230 ℃ to 240 ℃ and a pressure of less than 16 torr.

When the recovering step is carried out under the above-mentioned conditions, the unreacted monomer and the solvent contained in the polymerization product can be easily recovered.

The rubber average particle diameter of the graft copolymer prepared by the method for preparing a graft copolymer according to one embodiment of the present invention may be 2 μm to 5 μm, preferably 2.5 μm to 4.5 μm, and more preferably 3 μm to 4.2 μm.

When the rubber average particle diameter of the graft copolymer falls within the above range, a graft polymer having an excellent injection surface while obtaining matte characteristics can be prepared. When the rubber average particle diameter of the graft copolymer is less than the above range, matte properties cannot be obtained, and when the rubber average particle diameter of the graft copolymer is greater than the above range, a graft copolymer having a poor injection surface is obtained.

The graft copolymer prepared by the preparation method of the graft copolymer according to one embodiment of the present invention may have a degree of grafting of 35% to 60% or 40% to 55%, and preferably the degree of grafting is 40% to 55%.

When the graft degree of the graft copolymer falls within the above range, a graft polymer having an excellent injection surface while obtaining matte characteristics can be prepared.

2. Graft copolymers

The graft copolymer prepared by the preparation method of the graft copolymer according to one embodiment of the present invention may have a gloss of 22% or less measured according to ASTM 1003.

The graft copolymer may have a gloss measured according to ASTM1003 of 16% or less or 12% or less, and the gloss is preferably 12% or less. When the gloss of the graft copolymer falls within the above range, matte characteristics can be obtained. When the gloss of the graft copolymer is more than 22%, the graft copolymer cannot obtain matte properties.

In addition, the graft copolymer may have an excellent injection surface and may also exhibit excellent impact strength.

Hereinafter, the present invention will be described in detail with reference to embodiments so that those skilled in the art can easily implement the present invention. This invention may, however, be embodied in several different forms and should not be construed as limited to the embodiments set forth herein.