KR20120042802A - Method for producing a thermoplastic having highly heat resistance and scratch resistance and its components - Google Patents

Abstract

PURPOSE: A thermal resistant block copolymer is provided to improve heat resistance, scratch resistance and weather resistance of a resin in case of mixing with an ABS resin, etc, without harming physical properties of existing methylmethacrylate-styrene- acrylonitrile terpolymer. CONSTITUTION: A thermal resistant block copolymer comprises 65-80 weight% of methylmethacrylate, 0.5-10 weight% of N-substituted maleimide monomer, 1-10 weight% of vinyl cyanide monomer, and 10-20 weight% of styrene based monomer. The weight average molecular weight of the 4-membered copolymer is 80,000-120,000. A manufacturing method of the copolymer comprises a step of continuous bulky polymerization of monomer mixture consisting of methylmethacrylate, N-phenylmaleimide, acrylonitrile and styrene.

Description

Thermoplastic resin composition and manufacturing method excellent in heat resistance and scratch resistance {Method for producing a thermoplastic having highly heat resistance and scratch resistance and its components}

The present invention relates to a thermoplastic resin composition having excellent scratch resistance and heat resistance, and more particularly, to improve scratch resistance without compromising the mechanical properties of a conventional methyl methacrylate-styrene-acrylonitrile terpolymer. The present invention relates to a 4-membered block copolymer composed of methyl methacrylate, N-substituted maleimide, vinyl cyanide monomer, and styrene-based monomers that overcome the heat resistance limit.

ABS resin has excellent properties such as styrene processability, moldability, colorability, acrylonitrile stiffness, chemical resistance, dimensional stability, butadiene impact resistance and physical properties, and electric and electronic products, toys, It is widely used for office equipment parts. However, ABS resin itself has limitations in use in parts such as automobiles and exterior materials requiring heat resistance, and display fields requiring weather resistance and scratch resistance. In addition, there is a disadvantage that the use is limited because of poor transparency.

In order to solve the transparency problem of ABS resin, transparent ABS having transparency was developed by matching the refractive index of rubber matrix with the refractive index of continuous phase matrix resin, wherein the resin used as matrix is methyl methacrylate-styrene-acrylonitrile copolymer. (Hereinafter "SAN") is commonly used. However, there is still a problem that such a transparent ABS is limited in applications requiring both scratch and heat resistance.

As a method for producing an ABS resin having excellent heat resistance, a method of introducing a monomer having excellent heat resistance or adding an inorganic material to a part of the composition has been developed. A common method for introducing a monomer having excellent heat resistance is a method of adding a maleimide-based or alphamethylstyrene-based monomer during the polymerization process or blending a heat-resistant copolymer resin containing the monomer with an ABS resin.

The heat-resistant copolymer resin used as the matrix resin of the ABS resin is generally made by copolymerizing or tertiary copolymerizing a maleimide monomer or an alphamethyl styrene monomer with a vinyl cyanide compound such as acrylonitrile or an aromatic vinyl monomer such as styrene. .

However, since the maleimide monomer has a very fast polymerization rate, it is very difficult to control the reaction temperature, and the alphamethylstyrene monomer has a very slow polymerization rate and thus requires a long reaction time. The disadvantage is low and pyrolysis can easily occur. Due to these characteristics, the production method is usually prepared by emulsion polymerization in a batch process that is easy to control the reaction time. Emulsion polymerization method is generally composed of polymerization, agglomeration, dehydration and drying process, and the process itself is complicated, and impurities such as water, flocculant, emulsifier, etc. can be contained in the resin itself, and the waste water treatment problem is expensive. . In addition, it may also cause problems of heat resistance and lowering due to the presence of residual monomers.

In addition, the production method using the maleimide monomer has a limitation in increasing the maleimide monomer in the resin because the reaction rate is very fast and the heat of reaction is also high, and the more the monomer is contained, the more compatibility and impact with the ABS resin There is also a problem of lowering strength.

On the other hand, a widely popular method for compensating the weather resistance and surface scratch resistance of acrylonitrile-butadiene-styrene resin is a method of blending polymethyl methacrylate (PMMA) resin to the ABS resin (US 7173093 B2, US 5489633) has been developed. Korean Patent Laid-Open Publication No. 10-2001-0063763 intends to improve thermal discoloration of PMMA using a polyfunctional high temperature initiator, and Korean Patent Laid-Open Publication No. 10-2004-0105464 discloses butadiene-styrene-methyl in an acrylate-styrene-acrylonitrile resin. By devising a method of blending methacrylate terpolymer and alkyl acrylate copolymer, acrylate-styrene-acrylonitrile has excellent basic properties and weather resistance and excellent appearance characteristics such as scratch resistance, color and gloss. An attempt was made to provide a thermoplastic resin composition.

However, the matrix resin prepared by the above technique has technical limitations and economic problems, and has a disadvantage in that it cannot simultaneously improve heat resistance, weather resistance, and scratch resistance. Accordingly, there is a continuing need for a heat resistant copolymer capable of simultaneously improving the heat resistance, weather resistance, and scratch resistance of the ABS resin.

An object of the present invention is to provide a novel methyl methacrylate based bulk copolymer.

Another object of the present invention is to provide a novel heat resistant block copolymer which can simultaneously improve scratch resistance, heat resistance and weather resistance of ABS resin.

Still another object of the present invention is to provide a method for producing a methylmethacrylate-based quaternary block copolymer.

In order to achieve the above object, the bulk copolymer according to the present invention is 65 to 80% by weight of methyl methacrylate, 0.5 to 10% by weight of N-substituted maleimide monomer, 1 to 10% by weight of vinyl cyanide monomer, and styrene It consists of a tetrapolymer of 10-20 weight% of a system monomer.

In the present invention, the methyl methacrylate is 65 to 80% by weight, preferably 66 to 75% by weight. When the amount of methyl methacrylate is 65% by weight or less, the scratch resistance and weather resistance is lowered, when the amount of methyl methacrylate is 80% by weight or more, the viscosity of the reactant rapidly rises due to rapid reaction, making it difficult to control the polymerization rate.

In the present invention, the N-substituted maleimide monomer is not limited in theory, but is used to prevent a decrease in the heat resistance and thermal stability of the quaternary copolymer in the quaternary block copolymer.

In the present invention, the N-substituted maleimide monomer is N-phenyl maleimide, maleimide, N-methyl maleimide, N-ethyl maleimide, N-propyl maleimide, N-isopropyl maleimide, N-butyl Maleimide, N-isobutylmaleimide, Nt-butylmaleimide, N-cyclohexylmaleimide, N-chlorophenylmaleimide, N-methylphenylmaleimide, N-bromophenylmaleimide, N-naphthylmaleimide Mead, N-laurylmaleimide, N-hydroxyphenylmaleimide, N-methoxyphenylmaleimide, N-carboxyphenylmaleimide, N-nitrophenylmaleimide, N-benzylmaleimide and small amounts copolymerizable with these Monomers, and mixtures thereof. In a preferred embodiment of the present invention, the N-substituted maleimide monomer is N-phenylmaleimide, and can be purchased commercially.

In a preferred embodiment of the present invention, the N-phenylmaleimide is preferably used in the range of 0.5-10% by weight in the bulk block copolymer, more preferably 0.5-9% by weight. When the amount of the maleimide monomer is 0.5% by weight or less, the increase in heat resistance of the resin is insignificant, and when the content is increased, it is very difficult to control the reaction rate in the bulk reaction. In general, since the maleimide monomer has a characteristic of having a very fast polymerization rate that makes it difficult to control the reaction temperature, there is a limit in increasing the maleimide monomer in the resin. There is also a problem of lower compatibility and impact strength with.

In the present invention, the vinyl cyanated monomer is not limited in theory and serves to exhibit chemical resistance and heat resistance, and more preferably, serves as a cross-linking agent to contribute to dimensional stability of the resin during molding.

In the present invention, the vinyl cyanated monomer may be acrylonitrile, methacrylonitrile, ethacrylonitrile, phenyl acrylonitrile, α-chloroacrylonitrile, and the like, preferably acrylonitrile.

In a preferred embodiment of the present invention, the acrylonitrile in the quaternary copolymer is 1 to 10% by weight, more preferably 3 to 10% by weight. When the content of the vinyl cyanated monomer is 1 wt% or less, a decrease in chemical resistance occurs, and when 10 wt% or more, there is a problem of thermal discoloration. In addition, in the present invention, the ratio of the styrene-based monomer and acrylonitrile is important, and the ratio of the two monomers is 4: 1. This is because haze may occur due to a difference in refractive index when using monomers other than styrene-based monomers and acrylonitrile.

In the present invention, the styrene monomers include styrene, α-methylstyrene vinyltoluene, t-butylstyrene, halogen-substituted styrene, 1,3-dimethylstyrene, 2,4-dimethylstyrene, ethyl styrene, or mixtures thereof. Etc. can be used.

In the practice of the invention, the styrene-based monomers are used for moldability and coexistence in the quaternary copolymer, and play an important role in the flowability of the resin and the colorability by pigments and dyes. Preferably it is 10-30 weight%, More preferably, it is good to use in the range of 10-20 weight%. If the content of the styrene monomer is less than 10% by weight, workability problems occur, and when using more than 30% by weight, the refractive index is not easily adjusted, resulting in a decrease in transparency of the resin.

In the present invention, the weight average molecular weight of the quaternary copolymer is preferably 8 to 150,000, more preferably 10 to 120,000. When the molecular weight of the quaternary copolymer is 80,000 or less, there is a problem in that the overall physical properties of the resin is lowered, and in the case of 150,000 or more, there is a problem in that workability is lowered due to a decrease in fluidity of the resin. In addition, the molecular weight distribution of the quaternary copolymer is preferably 2.0 or less, which means that when the molecular weight distribution defined by the ratio of the weight average molecular weight and the number average molecular weight is larger than 2.0, a lot of low molecular weight resins are made at the same weight average molecular weight. Impact resistance, scratch resistance and heat resistance may be lowered.

In a preferred embodiment of the present invention, the quaternary copolymer itself has excellent transparency, surface strength, heat resistance, chemical resistance characteristics, heat resistance temperature, that is, Tg is 105 ~ 115 ℃ high to act as a matrix when kneading with other products The scratch, weather and heat resistance of the final product can be improved at the same time, especially the heat resistance can be greatly improved.

In one aspect, the present invention is a monomer consisting of 65 to 80% by weight of methyl methacrylate, 0.5 to 10% by weight of N-substituted maleimide monomer, 1 to 10% by weight of vinyl cyanide monomer, and 10 to 20% by weight of styrene monomer. Provided is a method for bulk polymerizing a mixture to produce a four-membered bulk copolymer for heat resistance.

In the present invention, the bulk polymerization polymerizes the monomer mixture at a constant conversion rate in the polymerization tank, and then recovers the unreacted monomer from the polymer polymerized in the devolatilizer to produce a polymer, and the recovered unreacted monomer is added to the polymerization tank again. It can be made of a continuous polymerization process used.

In the present invention, the polymerization tank may be used by connecting one or a plurality of agitator reactor, each of the agitator reactor may be further connected to an additive or monomer input line to adjust the viscosity or the composition of the final product. .

In the present invention, the polymerization tank may be operated under a pressure or a reduced pressure therein, and the temperature of the polymer and monomer mixture of the polymerization tank in each polymerization tank during the polymerization process to maintain the polymerization rate sufficiently is 110 ~ 140 It is preferable to keep it at ° C.

In the present invention, it is preferable that the conversion rate of the monomer in the polymerization tank is about 50 to 60% by weight. When the conversion rate exceeds 60%, the composition of the polymer produced at the beginning and the composition of the polymer produced at the end are In other words, even if the average refractive index is the same, there is a partial difference can cause a decrease in transparency. If it is less than 50% by weight it may have a uniform composition but economic problems arise for commercial applications. In the devolatilization process, it is preferable to convert to 60 to 70% by weight to separate the unreacted monomer.

In the practice of the present invention, the devolatilization device may be operated under reduced pressure for easy separation of unreacted monomers, and may be further attached to an extruder for producing a product.

In the present invention, the quaternary copolymer prepared through the bulk polymerization is 65-75% by weight of methyl methacrylate, 0.5-15% by weight of N-substituted maleimide, 3-10% by weight of vinyl cyanide monomer, styrene monomer 10 It includes ~ 20% by weight, the weight average molecular weight (Mw) is 8-150,000, the glass transition temperature is 105 ~ 115 ℃, has a low melt viscosity, the residual monomer content of the four-membered block copolymer is less than 2500ppm Is characterized. In a preferred embodiment of the present invention, the monomer mixture may further comprise 10 to 30 parts by weight of an organic solvent and less than 5000 ppm of initiator with respect to 100 parts by weight. The solvent may be a single organic solvent having a boiling point of 60 ~ 200 ℃, for example toluene, the initiator may be azobisisobutyronitrile, benzoyl peroxide, t-butylperoxy-2-ethyl-hexanoate, Cumyl peroxide, t-butylperoxide, 1,1-di (t-butylperoxy) cyclohexane or mixtures thereof and the like can be used.

In the present invention, the monomer mixture may include a molecular weight regulator to adjust the molecular weight. As said molecular weight modifier, n-dodecyl mercaptan, n-amyl mercaptan, t-butyl mercaptan, t-dodecyl mercaptan, n-hexyl mercaptan, n-octyl mercaptan, n-nonyl mercaptan or these It is preferable to use a mixture of 0 to 5000 ppm of a molecular weight regulator for 100 parts by weight of the monomer mixture.

The production method according to the bulk polymerization method of the present invention will be described in more detail as a raw material metering step, a polymerization step, and an analysis step.

[Weighing step]

In preparing the N-phenylmaleimide copolymer resin of the present invention, 60-80 wt% of methyl methacrylate, 10-20 wt% of styrene, 0.5-15 wt% of N-phenylmaleimide, and 1-10 wt% of acrylonitrile It is preferable to add a monomer mixture of%, the quaternary copolymer resin prepared is 65-75% by weight of methyl methacrylate, 3-10% by weight of acrylonitrile, 0.5% of N-phenylmaleimide It is preferable that -10 weight% and styrene contain 10-20 weight%.

[Polymerization stage]

Initiators used in the invention having a di-end functional group - preferably a butyl peroxide (Di- tert -butylperoxide) - tert. Reaction temperature of the reactor is maintained at 110 to 140 ℃, polymerization time 1 hour to 3 hours to convert 50 to 65% by weight of the monomer introduced into the polymer. The solvent used in the present invention is used to control the polymerization rate and the reaction temperature, ethylbenzene, toluene and the like can be used.

[Analysis step]

The solution discharged by polymerization is introduced into a devolatilizer maintaining a temperature of 200 to 250 ° C. and a vacuum pressure of 50 torr or less to volatilize the unreacted monomer and the solvent. The polymerization product was measured by molecular weight using gel chromatography (Waters), and the glass transition temperature (Tg) was measured using DSC (PERKIN ELMER).

Hereinafter, the present invention will be described in detail with reference to the following Examples and Comparative Examples, but the present invention is not limited to the Examples.

According to the present invention, there is provided a quaternary copolymer composed of methyl methacrylate-N-substituted maleimide monomer-vinyl cyanide monomer-styrene monomer. Such a heat-resistant copolymer was mixed with an ABS resin to provide a resin having good heat resistance and good weather resistance and scratch resistance.

In addition, the present invention provides a bulk polymerization method capable of increasing heat resistance while solving problems such as the inclusion of impurities in the resin due to the conventional emulsion polymerization method, difficulty in obtaining a high molecular weight due to a low polymerization temperature, and an increase in cost.

Example  One

77 parts by weight of monomer methyl methacrylate, 4.7 parts by weight of acrylonitrile, 17.3 parts by weight of styrene, 1 part by weight of N-phenylmaleimide, 20 parts by weight of toluene solvent, and dibutyl butyl peroxide catalyst in a reactor having a capacity of 100 L After 0.015 parts by weight of the mixture was mixed uniformly, this mixture was added to the reactor. The volume of the reaction solution in the reactor was 30L. The polymerization was carried out for 2 hours while maintaining the reaction temperature at 135 ° C. After removing the unreacted monomer and the solvent while maintaining the polymerization solution at a temperature of 250 ° C. and a vacuum pressure of 20 torr at a polymerization rate of 55%, the molecular weight was determined using gel chromatography (Waters), and the glass transition temperature (Tg). Was measured using DSC (PERKIN ELMER).

Table 1 shows the properties of the copolymerized heat resistant resin.

Example  2

In the same manner as in Example 1, 75 parts by weight of methyl methacrylate and 3 parts by weight of N-phenylmaleimide were added to show the properties of the copolymerized heat resistant resin in Table 1.

Example  3

In the same manner as in Example 1, methylmethacrylate 73, 5 parts by weight of N-phenylmaleimide was added to 5 parts by weight of the copolymerized heat-resistant resin is shown in Table 1.

Example  4

In the same manner as in Example 1, 68 parts by weight of methyl methacrylate and 10 parts by weight of N-phenylmaleimide were added to show the properties of the copolymerized heat resistant resin in Table 1.

Comparative example  One

In the same manner as in Example 1, N-phenylmaleimide was added to 0 parts by weight to show the characteristics of the copolymerization heat resistant resin in Table 1.

Comparative example  2

In the same manner as in Example 1, N-phenylmaleimide was added to 0 parts by weight, and 0 parts by weight of determinator peroxide was added to show the properties of the copolymerization heat resistant resin in Table 1.

Item Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Raw material composition
(Parts by weight) Methyl methacrylate 77 75 73 68 78 78 Acrylonitrile 4.7 4.7 4.7 4.7 4.7 4.7 Styrene 17.3 17.3 17.3 17.3 17.3 17.3 N-phenylmaleimide One 3 5 10 0 0 Subsidiary Composition
(Parts by weight) toluene 20 20 20 20 20 20 DTBP 0.03 0.01 0 0 0.03 0 characteristic Tg (占 폚) 100 103 106 112.5 98.5 89.09 Weight average molecular weight 10.42 12.52 13.23 12.23 7.08 13.97

Claims (10)

65 to 80% by weight of methyl methacrylate, 0.5 to 10% by weight of N-substituted maleimide monomer, 1 to 10% by weight of vinyl cyanide monomer, and 10 to 20% by weight of styrene-based monomer, and are copolymerized heat-resistant air coalescence. The N-substituted maleimide monomer according to claim 1, wherein the N-substituted maleimide monomer is N-phenylmaleimide, maleimide, N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-isopropylmaleimide, N- Butyl maleimide, N-isobutyl maleimide, Nt-butyl maleimide, N-cyclohexyl maleimide, N-chlorophenyl maleimide, N-methylphenyl maleimide, N-bromophenyl maleimide, N-naphthyl Maleimide, N-laurylmaleimide, N-hydroxyphenylmaleimide, N-methoxyphenylmaleimide, N-carboxyphenylmaleimide, N-nitrophenylmaleimide, N-benzylmaleimide and one or more thereof A heat resistant copolymer selected from the group consisting of mixtures. The heat-resistant copolymer according to claim 1, wherein the weight average molecular weight of the quaternary copolymer is 8 to 120,000. The heat-resistant copolymer according to claim 1, wherein the Tg of the quaternary copolymer is 105 to 115 ° C. Continuous mass polymerization of the monomer mixture consisting of methyl methacrylate, N-phenylmaleimide, acrylonitrile and styrene yielded 65 to 80% by weight of methyl methacrylate, 0.5 to 10% by weight of N-substituted maleimide monomer, and vinyl 1 to 10% by weight of cyanide monomer, and 10 to 20% by weight of a styrene monomer. The method of claim 5, wherein the reaction mixture is reacted at 110 to 140 ° C. in a reaction tank and then devolatilized at 200 −250 ° C. in a devolatilizer. The method for producing a heat resistant copolymer according to claim 5 or 6, wherein the residual monomer content of the quaternary block copolymer is 2500 ppm or less. The method of claim 5 or 6, wherein the conversion rate of the monomer in the polymerization reactor is 50 to 60% by weight, the conversion rate of the devolatilizer is 60 to 70% by weight. The method for producing a heat-resistant copolymer according to claim 5, wherein 100 parts by weight of the monomer mixture is mixed with 10 to 30 parts by weight of the solvent. Heat-resistant ABS resin prepared using the copolymer according to any one of claims 1 to 3.