JP2643343B2 - Method for producing thermoplastic resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION a. Industrial Field of the Invention The present invention relates to a method for producing a thermoplastic resin having excellent transparency, heat resistance, weather resistance and impact resistance, and a method for producing a thermoplastic resin containing the thermoplastic resin. The present invention relates to a plastic resin composition. More specifically, in the presence of a hydrogenated diene rubbery polymer,
A polymer having a refractive index substantially equal to that of the rubbery polymer is obtained by mixing a monomer mixture composed of a (meth) acrylate, an N-substituted maleimide compound, and another vinyl monomer copolymerizable therewith. The present invention relates to a method for producing a thermoplastic resin, the composition of which is selected and graft-polymerized.

b. Conventional technology In general, polymethyl methacrylate resin or resin containing methyl methacrylate as a main component has excellent properties such as transparency, gloss, and weather resistance.
It is used in a wide range of fields such as displays, but has the disadvantage of low impact strength. As a method of improving the impact strength, a vinyl monomer mixture composed of methyl methacrylate, styrene and acrylonitrile in the presence of a diene rubber such as polybutadiene is used. There is known a method in which the composition of a vinyl-based monomer mixture is selected and polymerized so that the refractive index of a polymer obtained by polymerizing the monomer alone substantially matches. Methyl methacrylate-butadiene-styrene copolymer resin and methyl methacrylate-butadiene-styrene-acrylonitrile copolymer resin obtained by this method are used in various fields. However, since these resins contain unsaturated double bonds in the molecular main chain, they are deteriorated by ultraviolet rays or oxygen in the air, causing discoloration and reduced impact resistance. Disadvantages.

As a method for improving the weather resistance, a method has been proposed in which, instead of the diene rubber, a rubbery polymer having a substantially saturated molecular main chain is used, and various vinyl monomers are graft-polymerized thereto. I have. However, since this rubber-like polymer does not have a double bond like a diene rubber and has low radical activity, a vinyl monomer is not graft-polymerized on the rubber-like polymer. Often becomes a blend with. For this reason, when the obtained resin is injection-molded, the surface has irregularities, gloss and transparency are extremely low, and various properties such as impact resistance and tensile strength are poor.

Furthermore, since these resins have low heat resistance, their action is required in fields requiring so-called semi-engineering plastic performance, such as high-end household goods, materials for light electricity, precision industrial materials, and automobile durable materials. At present it is severely restricted.

Eliminate the disadvantages of such methyl methacrylate resin,
In order to improve heat resistance, there is a method in which a monomer such as α-methylstyrene-methacrylic acid, maleic anhydride, or the like is copolymerized with these resins.

However, a methyl methacrylate resin obtained by copolymerizing these monomers has improved heat resistance, but has problems in heat stability, moldability, and the like.

c. Problems to be Solved by the Present Invention The inventors of the present invention have conducted intensive studies on these problems, and as a result, have found that (meth) acrylic acid ester and N-substituted maleimide The present inventors have found that a thermoplastic resin capable of solving the above-mentioned problems can be obtained by graft-polymerizing a compound and another vinyl monomer copolymerizable therewith, and have reached the present invention.

d. Means for Solving the Problems That is, the present invention comprises a polymer obtained by hydrogenating a random copolymer consisting of an aromatic vinyl compound and a conjugated diene compound, or the polymer, and an aromatic vinyl compound and a conjugated diene compound. The glass transition temperature of a homopolymer in the presence of 5 to 70% by weight of a hydrogenated diene rubbery polymer (I) comprising a mixture of a polymer obtained by hydrogenating a block copolymer is 50 ° C. (Meth) acrylic acid ester compound (a) 45 to 96% by weight, N-substituted maleimide compound (b) 2 to 50% by weight, and another vinyl monomer copolymerizable therewith (c) 53 to 2% by weight % Of a monomer mixture (II), which is graft copolymerized with 95 to 30% by weight of a monomer mixture (II), the refractive index of the polymer (I) and the monomer mixture (II) ) When copolymerized only) As the difference between the rate becomes 0.01 or less, the monomer (a), there is provided a (b) and method for producing a thermoplastic resin, characterized by selecting the composition of (c).

 Hereinafter, the present invention will be described in detail.

Examples of the hydrogenated diene rubbery polymer (I) of the random (and block) copolymer comprising an aromatic vinyl compound and a conjugated diene compound used in the present invention include a random (and block) copolymer of styrene and butadiene. It is obtained by hydrogenating a polymer, thereby saturating an aliphatic double bond based on a conjugated diene compound and converting it into an olefinic polymer.

Examples of the aromatic vinyl compound include styrene, α-methylenestyrene, vinyltoluene and the like, and among them, styrene is preferred. Examples of the conjugated diene compound include butadiene, isoprene, 1,3-pentadiene, 2,3
-Dimethyl-1,3-butadiene and the like, among which butadiene, isoprene and a combination thereof are preferred.

The mixing ratio of the aromatic vinyl compound and the conjugated diene compound is not particularly limited, but the aromatic vinyl compound / conjugated diene compound is 5-60 / 95- It is preferably 40% by weight, particularly preferably 10-50 / 90-50.

The molecular structure of this block and random copolymer is
Any of linear, branched, radial or a combination thereof may be used.
Any of a triblock, a multiblock, and a combination thereof may be used. The hydrogenation rate of these random (and block) copolymers is not particularly limited, but is preferably 50% or more, more preferably
It is at least 65%, particularly preferably at least 80%. If it is less than 50%, the weather resistance tends to decrease, which is not preferable.

As a method for producing these hydrogenated block copolymers, a general method can be used, and typical methods are described in, for example, JP-B-42-8704 and JP-B-43-6636. There is a way. As such a hydrogenated block copolymer, a commercially available polymer, KRATON-G
(A product name of Shell Chemical Co., Ltd.) can also be used.

As a method for producing a hydrogenated random copolymer, a method proposed in Japanese Patent Application No. 63-104256 can be used. Compared to using a hydrogenated block copolymer,
The use of a hydrogenated random copolymer is preferred because a resin having excellent weather resistance can be obtained.

In the present invention, a monomer mixture (I) graft-polymerized to a hydrogenated random (and block) copolymer rubber is used.
As (I), it is necessary to use (meth) acrylic acid ester, N-substituted maleimide and another vinyl monomer copolymerizable therewith.

The above (meth) acrylic acid ester compound (a) has a glass transition temperature (measured by a differential scanning calorimeter (DSC)) of 50 ° C. or higher when the polymer alone is used as a polymer, The alkyl preferably has 1 to 10 carbon atoms, more preferably 1 to 6, particularly preferably 1 to 6.
4 things. Of the methacrylates and acrylates, methacrylates are preferred.
Examples of these include methyl methacrylate, ethyl methacrylate, cyclohexyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate,
T-butylcyclohexyl methacrylate, butyl methacrylate, hexyl methacrylate, (meth) acrylic ester represented by the following formula (N is 0 to 3, R hydrogen atom or alkyl group, m is 3
To 4), and one or more of these can be used. Of these, methyl methacrylate and ethyl methacrylate are preferred, and methyl methacrylate is more preferred.

Examples of the N-substituted maleimide compound (b) include N-cyclohexylmaleimide, N-methylmaleimide, N-ethylmaleimide, Nn-propylmaleimide, N-isopropylmaleimide, Nn-butylmaleimide,
-Sec-butylmaleimide, N-tert-butylmaleimide, N-octylmaleimide and the like can be used. These maleimide monomers have no coloration in the monomer itself, and the present invention obtained by using them. The resin also gives a molded article with less coloring, and the use of the resin is not limited.

On the other hand, in addition to the above monomers, N-phenylmaleimide, No-methylphenylmaleimide, Nm-
Methylphenylmaleimide, Np-methylphenylmaleimide, No-methoxyphenylmaleimide, N-
Aromatic substituted maleimides such as m-methoxyphenylmaleimide, Np-methoxyphenylmaleimide, No-chlorophenylmaleimide, Nm-chlorophenylmaleimide and Np-chlorophenylmaleimide can also be used. However, these aromatic-substituted maleimide compounds are colored yellow, and the copolymers obtained by using them are also colored yellow. You.

Among these N-substituted maleimide compounds (b), preferred are N-cyclohexylmaleimide, N-methylmaleimide, N-octylmaleimide, and N-isopropylmaleimide in consideration of the improvement in heat resistance. And the like.

Examples of other copolymerizable vinyl monomers (c) include aromatic vinyl monomers such as styrene, α-methylstyrene, and vinyl toluene; vinyl cyanide monomers such as acrylonitrile and methacrylonitrile The alkyl (meth) acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate, cyclohexyl acrylate, and cyclohexyl methacrylate; (Meth) acrylic acid alkyl ester monomers other than those used in (1); unsaturated acid anhydrides such as maleic anhydride and itaconic anhydride; and unsaturated acids such as acrylic acid and methacrylic acid.

When using the (meth) acrylate compound (a), the N-substituted maleimide compound (b) and the monomer (c) copolymerizable therewith, the hydrogenated diene rubbery polymer (I) The graft polymerization is carried out by appropriately selecting the composition of the monomer mixture (II) such that the difference between the refractive index of the copolymer and the refractive index of the copolymer of the monomer mixture (II) is 0.01 or less, preferably 0.005 or less. Here, if the difference between the two refractive indexes exceeds 0.01, the transparency of the thermoplastic resin is reduced. The refractive index of the copolymer composed of only the monomer mixture (II) can be calculated from the theoretical formula or measured in advance by measuring the refractive index of the copolymer obtained by polymerizing the monomer mixture composed of the composition in advance. You can know

The action ratio of the (meth) acrylate compound (a), the N-substituted maleimide compound (b) and the other vinyl monomer (c) is 45 to 96/2 to 50/53 to 2% by weight. The content is more preferably 55 to 95/3 to 40/42 to 3% by weight, and particularly preferably 65 to 90/5 to 30/30 to 4% by weight. If it deviates from the above range, it is not preferable because excellent physical properties such as weather resistance, heat resistance and moldability cannot be obtained. Within the above monomer range, the proportion of each monomer used can be appropriately determined according to the refractive index of the hydrogenated diene rubbery polymer (I).

The content of the hydrogenated diene-based rubbery polymer (I) in producing the thermoplastic resin of the present invention can be arbitrarily selected according to the purpose, but the impact resistance, heat resistance, and moldability of the resin can be selected. In order to satisfy transparency and transparency, the range is 5 to 70% by weight,
Preferably it is 10 to 65% by weight. More preferably 10 to
60% by weight. If the rubber content is less than 5% by weight, only a resin having insufficient impact resistance can be obtained, and if it exceeds 70% by weight, the graft ratio of the rubbery polymer is insufficient, and the transparency, moldability, heat resistance and Poor impact strength. The blending ratio of the monomer mixture (II) to be graft-copolymerized is 95 to 30 parts by weight, preferably 90 to 35 parts by weight, more preferably 90 to 60 parts by weight.

In the method for producing the thermoplastic resin of the present invention, known polymerization methods such as a solution polymerization method, a suspension polymerization method, a bulk polymerization method and an emulsion polymerization method can be employed. Legit is preferred.

The thermoplastic resin obtained by the method of the present invention thus obtained is
Excellent transparency, weather resistance, heat resistance and impact resistance,
It can be widely used for various applications utilizing these characteristics.

Further, this thermoplastic resin (A) can be blended with another transparent thermoplastic resin (B) according to the purpose to obtain the thermoplastic resin composition intended for the present invention. As other transparent thermoplastic resin (B), for example, methyl methacrylate-
N-cyclohexylmaleimide-styrene copolymer, methyl methacrylate-N-methylmaleimide-styrene copolymer, methyl methacrylate-N-cyclohexylmaleimide-styrene-acrylonitrile copolymer, polymethyl methacrylate, transparent ABS resin, MBS resin , Transparent AAS
Resin and polyvinyl chloride resin. However, this transparent thermoplastic resin (B) has a refractive index difference of 0.01 or less from the thermoplastic resin (A) obtained by the production method of the present invention,
It is preferably in the range of 0.05 or less, and if this condition is not satisfied, a transparent composition cannot be obtained.

The transparency of the transparent thermoplastic resin means that the total light transmittance in ASTM D1003 is preferably 50% or more, and the haze value in the same test method is preferably 20% or less.

The content of the hydrogenated diene rubbery polymer (I) in the composition comprising the thermoplastic resin (A) and the other transparent thermoplastic resin (B) is 5 to 35% by weight, preferably 10 to 30% by weight. If it is less than 5% by weight, the impact resistance is poor, and
Exceeding the weight% is not preferable because the moldability, heat resistance and transparency are inferior.

In addition, the thermoplastic resin produced by the method of the present invention, and a composition using the same, a hindered phenol-based, phosphorus-based, and sulfur-based antioxidants, light stabilizers, ultraviolet absorbers, lubricants Additives commonly used, such as a colorant, a flame retardant, and a reinforcing agent, can be added within a range that does not impair the transparency.

e. Examples Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto. In the following examples, “parts” and “%” are “parts by weight”,
It represents "% by weight".

Various physical properties in the following examples were measured according to the following procedures.

(1) Refractive index: measured at 25 ° C. using an Abbe refractometer.

(2) Izod impact strength: ASTM D-256 (1/4 × 1 cross section)
(3) Total light transmittance, cloudiness value: ASTM D-1003 (3.2mm thickness) (4) Weather resistance: Exposure to a sunshine weatherometer using a carbon arc light source for 1000 hours, Izod Measure impact strength. The black panel temperature was 63 ± 3 ° C., and the water showering was 18 minutes every 2 hours.

(5) Heat deformation temperature: ASTM D-648 Example-1 A hydrogenated styrene-butadiene random copolymer was prepared by the following methods (1) and (2).

(1) Five autoclaves were charged with 2500 g of degassed and dehydrated cyclohexane, 150 g of styrene and 350 g of 1,3-butadiene, and then 2.5 g of tetrahydrofuran and 0.34 g of n-butyllithium were added, and the polymerization temperature was raised from 30 ° C to 80 ° C. Was carried out. After the conversion reached almost 100%, 0.14 g of SiCl ₄ was added. Then, 2,6-di-tert-
Butyl catechol was added, and the solvent was removed by a steam stripping method, followed by drying with a hot roll at 120 ° C. to obtain a polymer. The styrene-butadiene copolymer thus obtained had a vinyl bond content of 30%, a styrene content (Bd-ST) of 30% by weight, and a tri- or more branched polymer of 56% by weight. GCP
The number average molecular weight by analysis was 120,000, and Mw / Mn was 1.5.

(2) The conjugated diene polymer polymerized in (1) was charged into 3 autoclaves to obtain a 15% cyclohexane solution. After replacing the system with nitrogen, a catalyst solution of nickel naphthenate: n-butyllithium: tetrahydrofuran = 1: 8: 20 (molar ratio) prepared in a separate container in advance was added to the olefin portion 20.
The nickel was charged so as to be 1 mol with respect to 00 mol. Thereafter, hydrogen was introduced into the reaction system, and a hydrogenation reaction was performed at 70 ° C. After controlling the hydrogenation rate based on hydrogen and absorption consumption, replace the hydrogen in the system with nitrogen, and add the anti-aging agent 2,6-di-tert-butylparacresol to 1PHR.
Was added. After repeated contact and coagulation, roll drying was performed by a conventional method to obtain a hydrogenated diene-based random copolymer having a hydrogenation ratio of 95% (hereinafter referred to as base rubber No. 1).

(3) A hydrogenated random copolymer 2 having a refractive index of 1.507 obtained in (2) and previously prepared in a homogeneous solution in a stainless steel autoclave having an internal volume of 15 liters equipped with a paddle type stirring device 2
5 parts, styrene 7.8 parts, N-cyclohexylmaleimide 10
Part, toluene 130 parts and t-dodecyl mercaptan 0.1
Then, the mixture was heated while stirring, and 57.2 parts of methyl methacrylate and 0.5 part of benzoyl peroxide were added at 50 ° C. After the inside of the system was replaced with nitrogen, the temperature was further raised to 85 ° C., and the polymerization was continued under stirring at this temperature until the polymerization conversion rate became 95% or more. When the polymerization conversion reached 95% or more, the polymerization was stopped. After adding an antioxidant, the polymerization reaction was taken out of the autoclave, and the unreacted monomer and the solvent were removed by steam distillation. The product was finely pulverized and dried, and then pelletized with a 40 mmφ vented extruder.

The graft copolymer pellets obtained by the above method were molded into test pieces using an injection molding machine, and the physical properties were measured. The results are shown in Table 1. The refractive index of the copolymer resin composed of only the monomer mixture was 1.5065.

Comparative Example-1 Hydrogenated block copolymer KRATONG-16 having a refractive index of 1.507
Using 50 25 parts, the composition of the monomer mixture was
Parts, N-cyclohexylmaleimide 10 parts and methyl methacrylate 45.5 parts, and polymerization and post-treatment were carried out in the same manner as in Example 1 to evaluate. Table 1 shows the results.
It was shown to. The refractive index of the copolymer resin composed of only the monomer mixture was 1.5200.

Comparative Example 2 8.9 parts of styrene as the monomer mixture in Comparative Example 1,
Polymerization and post-treatment were carried out and evaluated in the same manner as in Comparative Example 1, except that 1 part of N-cyclohexylmaleimide and 65.1 parts of methyl methacrylate were used. The results are shown in Table 1. The refractive index of the copolymer resin composed of only the monomer mixture was 1.5049.

Comparative Example-3 The composition of the monomer mixture in Comparative Column-1 was styrene 6.
Polymerization and post-treatment were performed in the same manner as in Comparative Example 1, except that 0 part, 55 parts of N-cyclohexylmaleimide and 24.0 parts of methyl methacrylate were evaluated. Table-Results
1 is shown. The refractive index of the copolymer resin composed of only the monomer mixture was 1.5227.

Comparative Example-4 Hydrogenated diene rubber-like polymer having a refractive index of 1.507 KRATONG
Using -1650 3 parts, the composition of the monomer mixture was
Parts, N-cyclohexylmaleimide 15 parts and methyl methacrylate 72.2 parts, polymerization and post-treatment were performed in the same manner as in Comparative Example 1 to evaluate. Table 1 shows the results.
It was shown to. The refractive index of the copolymer resin composed of only the monomer mixture was 1.5074.

Comparative Example-5 Hydrogenated diene rubbery polymer having a refractive index of 1.507 KRATONG
-1650 Using 35 parts, the composition of the monomer mixture was
Parts, N-cyclohexylmaleimide 10 parts and methyl methacrylate 33 parts, polymerization and post-treatment were performed in the same manner as in Comparative Example 1 to evaluate. The results are shown in Table 1. The refractive index of the copolymer resin composed of only the monomer mixture was 1.5312.

Comparative Example-6 Hydrogenated block copolymer KRATONG-1 having a refractive index of 1.5105
Using 20 parts of 701X, the composition of the monomer mixture was
Parts, N-cyclohexylmaleimide 15 parts and methyl methacrylate 45.5 parts, polymerization and post-treatment were performed in the same manner as in Comparative Example 1 to evaluate.

Comparative Example-7 Hydrogenated block copolymer KRATONG-16 having a refractive index of 1.507
Using 50 80 parts, the composition of the monomer mixture was 2.2 parts of styrene,
Polymerization and post-treatment were carried out in the same manner as in Example 6 except that 2 parts of N-cyclohexylmaleimide and 15.8 parts of methyl methacrylate were used, and a graft copolymer resin (1)
I got

Next, a monomer mixture having the same composition as (2) of Example-6 was polymerized and post-treated in the same manner as in Example-6 to obtain a transparent thermoplastic resin (2) product.

The above graft copolymerized copolymer resin (1) and the transparent thermoplastic resin (2) are mixed with each other so that the actual rubber amount of the graft copolymerized copolymer (1) is 25.
%, And evaluated in the same manner as in Example-6. The results are shown in Table 1. The refractive index of the copolymer resin (1) composed of only the monomer mixture was 1.5072, and the refractive index of the copolymer resin (2) was 1.5074.

Example 2 Hydrogenated Block Copolymer KRATONG-16 with Refractive Index 1.507
50 (manufactured by Shell Chemical Co., Ltd.) and 25 parts of a copolymer obtained by blending two kinds of base rubber No. 1 obtained in (1) of Example 1 at a ratio of 50:50 were used. Styrene 7.8 parts, N-cyclohexylmaleimide 10 parts,
Polymerization and post-treatment were performed in the same manner as in Example 1 except that 57.2 parts of methyl methacrylate was used, and evaluation was performed. The results are shown in Table 1. The refractive index of the copolymer resin from the monomer mixture alone was 1.5065.

From the results shown in Table 1, in Examples 1 and 2, SE
It can be seen that the use of a hydrogenated random (and block) copolymer such as BS or SEP can provide a thermoplastic resin or composition excellent in transparency, heat resistance, weather resistance and impact resistance.

On the other hand, in Comparative Examples 1 to 7, the effects of the present invention were not obtained.

e. Effects of the Invention The present invention relates to a method for producing a (meth) allylic acid ester compound, an N-methacrylate compound, in the presence of a hydrogenated random copolymer or a rubbery polymer comprising a mixture of a hydrogenated random copolymer and a hydrogenated block copolymer. The present invention provides a method for producing a novel thermoplastic resin obtained by graft polymerization of a substituted maleimide compound and other copolymerizable monomers under specific conditions. A thermoplastic resin and a thermoplastic resin composition having excellent heat resistance, weather resistance, impact resistance and moldability can be obtained.

Conventional transparent thermoplastic resins are inferior in physical property balance, and have been restricted for use outdoors and in applications where functions are required, but thermoplastic resins and thermoplastic resins obtained by the production method of the present invention. The composition has an excellent balance of physical properties, and can be developed for applications that have been restricted in conventional transparent thermoplastic resins, and has extremely high industrial value.

Continued on the front page (51) Int.Cl. ⁶ Identification number Reference number in the agency FI Technical indication (C08F 291/02 220: 18)

Claims (1)

(57) [Claims] A polymer obtained by hydrogenating a random copolymer consisting of an aromatic vinyl compound and a conjugated diene compound, or a block copolymer consisting of the polymer and an aromatic vinyl compound and a conjugated diene compound is hydrogenated. (Meth) acrylic ester compound having a glass transition temperature of 50 ° C. or higher when homopolymerized in the presence of 5 to 70% by weight of a hydrogenated diene rubbery polymer (I) comprising a mixture of polymers (A) 45 to 96% by weight of an N-substituted maleimide compound (b)
A monomer mixture (II) comprising 2 to 50% by weight and 53 to 2% by weight of another vinyl monomer (c) copolymerizable therewith;
A method for producing a thermoplastic resin by graft copolymerization of 95 to 30% by weight, wherein the copolymer is obtained by polymerizing only the refractive index of the polymer (I) and the monomer mixture (II). Monomer (a), so that the difference from the refractive index of the
A method for producing a thermoplastic resin, comprising selecting the compositions of (b) and (c).