JP2802076B2 - Method for producing comb copolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a comb copolymer suitable as an acrylic elastomer material having excellent transparency, weather resistance and mechanical properties,
Comb-type copolymer as an acrylic resin excellent in impact-resistant acrylic resin composition, transparency, weather resistance, gloss, and light resistance obtained by blending this comb-type copolymer with a PMMA-based polymer,
And a method for producing a high molecular weight comb copolymer useful as a molding material containing these comb polymers.

[Conventional technology]

Methyl methacrylate-based polymers have been conventionally used as cast resins, injection-molded products, extruded products, and the like as resins having excellent transparency, gloss, and weather resistance. However, on the other hand, it is difficult to make it into a film or sheet, for example, due to its hard and brittle nature, and its use is currently limited. Various methods have been proposed as methods for improving the disadvantages of being hard and brittle, such as a method of blending an elastomer with a methyl methacrylate polymer and a method of graft-polymerizing methyl methacrylate to an elastomer. In particular, since the method of graft-polymerizing methyl methacrylate on an elastomer has a large effect, various types of elastomers to be used and various methods of graft polymerization have been proposed.For example, as an elastomer, a diene-based elastic material such as polybutadiene is used. There has been proposed a method of using the method, a method of using an acrylic ester-based elastic body, and the like. However, in the former method,
The weather resistance is greatly reduced due to the double bond present in the elastic body, and the latter method has a small improvement effect compared to the former method. An acid ester elastic body must be used,
There is a problem that the transparency and gloss are inevitably reduced.

On the other hand, as a thermoplastic elastomer material, a styrene-diene-based block copolymer, a polyester-polyether-based block copolymer, and the like have been developed. However, for acrylic materials, satisfactory materials have not yet been obtained, despite the fact that elastomer materials are expected due to their excellent transparency and weather resistance.

As an attempt to develop an acrylic elastomer, for example, as in the case of a styrene-diene-based block copolymer, a method using anionic living polymerization has been attempted. However, satisfactory results have not been obtained due to the difficulty of complete living polymerization of acrylates. Also, a method of graft polymerizing a methacrylic acid ester to a crosslinked acrylic rubber has been attempted,
As the ratio of the acrylic rubber component increases, the moldability and transparency decrease, and no satisfactory products have been developed.

In addition, block copolymers and graft copolymers have been developed for the purpose of increasing the functionality and performance of polymer materials. Recently, oligomers and polymers having a polymerizable functional group at one end have been developed. Due to the progress of the synthesis technology, interest has been attracted to the development and application of graft copolymers using the same. The most common method for synthesizing a comb copolymer of such an oligomer or polymer and a normal vinyl monomer is to dissolve both in a suitable solvent together with a polymerization initiator and copolymerize the solution. However, there is also a method in which the above oligomer or polymer and a polymerization initiator are dissolved in a vinyl monomer to perform bulk polymerization or suspension polymerization.

However, although the above solution polymerization method has an advantage that polymerization is easy, there is a problem that chain transfer to a solvent is apt to occur, so that it is difficult to produce a high-molecular-weight comb copolymer, and mechanical properties Is difficult to use for applications requiring, for example, elastomers and molding materials. In addition, a method of dissolving an oligomer or a polymer in a vinyl monomer to perform bulk polymerization or suspension polymerization has an advantage that a high-molecular-weight one is easily obtained as compared with a solution polymerization method.
Since the solubility of the oligomer or polymer in the vinyl monomer is limited, there is a problem that it is difficult to obtain a comb copolymer having a high ratio of the oligomer or polymer component. In this way, while aiming to produce an unusual copolymer, only low-molecular-weight ones or those with a high ratio of vinyl monomer components can be obtained due to restrictions on the production conditions. The desired properties could not be fully received.

[Problems to be solved by the invention]

In view of such a situation, the present inventors have made intensive studies and arrived at the present invention.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a comb copolymer in which the ratio of the macromonomer constituting the branch portion to the vinyl monomer constituting the backbone of the comb copolymer can be selected from a wide range.

It is another object of the present invention to provide a production method capable of producing a comb copolymer having a considerably large molecular weight.

Still another object of the present invention is to provide a novel acrylic elastomer having a comb-shaped copolymer structure which retains the properties of an acrylic elastomer having excellent transparency and weather resistance.

Still another object of the present invention is to provide a comb-shaped copolymer resin as an acrylic resin having excellent impact resistance while retaining excellent properties of the acrylic resin such as transparency, weather resistance, and gloss. It is in.

Still another object of the present invention is to provide a methacrylic resin composition having improved impact resistance.

[Means for solving the problem]

That is, the method for producing the comb copolymer of the present invention comprises a polymer having a vinyl group at one end and a number average molecular weight of 30,000 to 50,000 and a vinyl monomer, which is a good solvent for the polymer and water at 30 ° C. It is characterized in that a polymerization initiator is mixed together in a solvent in which 10% by weight or more is dissolved, and the resulting mixture is subjected to aqueous suspension polymerization.

[Action]

Hereinafter, the method for producing the comb copolymer of the present invention will be described first.

The number average molecular weight of the macromonomer having a vinyl group at one end used in the method of the present invention must be 3,000 to 50,000. Even if a macromonomer having a molecular weight of less than 3000 is used, a comb copolymer having sufficient properties cannot be obtained,
In addition, a macromonomer having a molecular weight of more than 50,000 is not preferable because reactivity becomes low.

The monomer unit constituting the main chain of this macromonomer may be a normal radical polymerizable vinyl monomer,
Various methacrylates, acrylates, styrene, acrylonitrile and the like can be exemplified. Such macromonomers include, for example, methyl methacrylate (MMA)
A method of conducting anionic living polymerization such as anionic polymerization and then reacting with a halogen-containing vinyl compound; performing a radical polymerization of a vinyl monomer in the presence of mercaptoacetic acid, and then reacting the resulting polymer or oligomer with a glycidyl group-containing monomer such as glycidyl methacrylate. A method of polymerizing a vinyl monomer such as MMA using vinyl phenyl ketene trimethylsilyl acetal as an initiator.

This macromonomer constitutes a branch in the comb copolymer produced by the method of the present invention.

On the other hand, as the vinyl monomer used in the method of the present invention, any one can be used as long as it is a normal radically polymerizable vinyl monomer, and acrylates, methacrylates, styrene, acrylonitrile and the like are typical. Can be exemplified. These vinyl monomers may be used as a mixture of two or more kinds. However, considering the purpose of forming the comb copolymer, it is preferable to use a monomer of a type different from the monomer component forming the main chain of the macromonomer as the vinyl monomer.

The solvent used in the method of the present invention needs to be a good solvent for the macromonomer and has a solubility in water at 30 ° C. of 10% by weight or more. If the solubility of the solvent in water is less than 10% by weight, the solvent does not diffuse and dissolve in water during the polymerization, so that a considerable amount of the solvent remains near the monomer being polymerized and causes chain transfer. It is not preferable because it is difficult to obtain a polymer having a high molecular weight, and a large amount of a solvent remains in the produced polymer, causing fusion of the polymer and the like, which makes handling difficult. Further, it is preferable to select and use a solvent in consideration of the chain transfer constant of the solvent to the growing radical. When a solvent having a large chain transfer constant is used, the formation of a high molecular weight polymer tends to be disadvantageous even if the invention is devised. For example, preferred examples of the solvent when the macromonomer is a methyl methacrylate-based macromonomer include:
Acetone, methyl ethyl ketone, tetrahydrofuran,
Examples thereof include, but are not limited to, dioxane, acetonitrile, 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,2-diacetoxyethane, methyl acetate, and γ-butyrolactone.

The ratio of the macromonomer and the vinyl monomer used in the method of the present invention can be set to an arbitrary range depending on the desired comb copolymer, but is 95/5 to 10/9.
It is preferably in the range of 0, and more preferably in the range of 90/10 to 30/70. When the proportion of the macromonomer exceeds 95% by weight, it becomes difficult to obtain a polymer having a high molecular weight by the method of the present invention. When the proportion is less than 10% by weight, the polymer can be suspended without using the method of the present invention in which a solvent is mixed. Advantages are reduced because polymerization is possible. Solvent is macromonomer 10
It is preferable to use 30 to 300 parts by weight with respect to 0 parts by weight.
If the amount of the solvent used is less than 30 parts by weight, a sufficient diluting effect cannot be obtained, and it is difficult to sufficiently dissolve the macromonomer in the vinyl monomer. Stability also decreases.

As the polymerization initiator, ordinary initiators for radical polymerization can be used. Preferred examples thereof include peroxide initiators such as benzoyl peroxide and lauroyl peroxide, and azo initiators such as azobisisobutyronitrile. it can.

In the method of the present invention, the macromonomer, the vinyl monomer, and the radical polymerization initiator are mixed in a good solvent of the macromonomer to form a uniform solution, and the mixed solution is poured into water together with the dispersion stabilizer. Then, the mixture is sufficiently stirred to form a suspension, and polymerization is performed in this state.

That is, in the method of the present invention, a uniform mixed solution of a macromonomer, a vinyl monomer and a radical polymerization initiator is prepared by using a solvent, and a suspension is formed using this solution. At the stage when the suspension is formed, each suspended particle is composed of the above-mentioned homogeneous mixed solution. Although the solvent used in the present invention has a solubility of 10% by weight or more in water, it is also a good solvent for the macromonomer. It migrates from the particles into the aqueous medium, but not completely into the aqueous medium. As the polymerization in the suspended particles progresses, the solvent moves into the aqueous medium, and when the polymerization is completed, the solvent hardly remains in the suspended particles.

The ratio of the amount of water, which is the sum of the amount of the macromonomer and the vinyl monomer, to water is sufficient so that the stability of the polymerization is not hindered and that the entire amount of the solvent used to form the monomer mixture is dissolved and transferred in water. Monomer / water =
It is preferably 1 / 1.5 to 1/6, more preferably 1/3 to 1/5. Other suspension polymerization conditions may be those employed in ordinary suspension polymerization.

As the polymerization initiator, ordinary initiators for radical polymerization can be used. Preferred examples thereof include peroxide initiators such as benzoyl peroxide and lauroyl peroxide, and azo initiators such as azobisisobutyronitrile. it can.

Further, if necessary, a chain transfer agent such as n-octyl mercaptan may be used, but it is preferable to limit the use amount to a range where the molecular weight does not decrease significantly.

According to the method of the present invention, the obtained copolymer is usually obtained as polymer particles having a particle size of 10 μm to 2 mm as in the case of ordinary suspension polymerization, so that the reaction system is cooled, filtered, dehydrated, and washed. And recover the polymer.

Next, the acrylic comb copolymer of the present invention will be described.

The acrylic comb copolymer of the present invention has a vinyl group at one end, has a number average molecular weight of 3,000 to 50,000, and has a homopolymer having a glass transition temperature of 40 ° C. or higher, a methacrylic acid ester polymer. It is obtained by copolymerizing 20 to 90 parts by weight of methacrylic macromonomer and 80 to 10 parts by weight of acrylate monomer. Thus, a comb copolymer having slightly different physical properties and applications can be obtained.

The acrylic comb copolymer obtained by copolymerizing 20 to 60 parts by weight of a methacrylic macromonomer and 80 to 40 parts by weight of an acrylate monomer has transparency, weather resistance,
It is useful as an elastomer having excellent mechanical properties, and is hereinafter abbreviated as "comb-shaped elastomer".

On the other hand, an acrylic comb copolymer obtained by copolymerizing 60 to 90 parts by weight of a methacrylic macromonomer and 40 to 10 parts by weight of an acrylate monomer has transparency, weather resistance, gloss and impact resistance. It is useful as an excellent acrylic resin, and is hereinafter abbreviated as "comb-shaped resin".

The methacrylic macromonomer used in the present invention has a number average molecular weight of 3,000 to 50,000, has a vinyl group at one end, and has a glass transition temperature of a homopolymer of 40 ° C.
The above is a methacrylic acid ester macromonomer.

Examples of such a methacrylic macromonomer include homopolymers such as methyl methacrylate, ethyl methacrylate, phenyl methacrylate, t-butyl methacrylate, and cyclohexyl methacrylate, and macromonomers of copolymers thereof. Can be.

When a methacrylic macromonomer having a number average molecular weight of less than 3000 is used, a comb copolymer having sufficient mechanical properties cannot be obtained. Conversely, the number average molecular weight is 50
When the amount exceeds 000, not only the synthesis of the comb copolymer becomes difficult due to the decrease in the reactivity, but also the transparency and impact resistance of the obtained comb copolymer decrease.
The more preferable range of the number average molecular weight of the methacrylic macromonomer is 4,000 to 30,000.

Further, if the glass transition temperature of the homopolymer of methacrylic acid ester constituting the methacrylic macromonomer is less than 40 ° C., it is not suitable because a comb copolymer excellent in mechanical properties and weather resistance cannot be obtained. .

Such a methacrylic macromonomer can be produced by various conventionally known methods. For example, a method in which anionic living polymerization of methacrylic acid ester is performed in a solvent that has been sufficiently dehydrated and purified under a low temperature and high vacuum, and then the living polymer is reacted with a halogen-containing vinyl compound to form a macromonomer; In the presence of a chain transfer agent having a carboxyl group such as acetic acid, by performing radical polymerization of methacrylic acid ester, by reacting the resulting oligomer of terminal carboxylic acid with a vinyl compound having a glycidyl group such as glycidyl methacrylate. how to macromonomer of, and compounds such as ketene trimethylsilyl acetal and initiator, an inert gas ^{_{atmosphere, HF 2 -, (CH 3}} ) SiF 2 -, F - the presence of the supply source to become the compounds of the anions such as Perform the living polymerization of methacrylic acid ester in a solvent that has been sufficiently dehydrated and purified. A method of reacting a living polymer with a halogen-containing vinyl compound such as p-vinylbenzyl bromide to form a macromonomer; and using a ketene silyl acetal having a styryl group such as vinylphenylketene trimethylsilyl acetal as an initiator in an inert gas atmosphere. below, HF ₂ ^-,
It can be produced by, for example, a method of polymerizing a methacrylic acid ester in a solvent which has been sufficiently dehydrated and purified in the presence of a compound serving as a source of an anion such as (CH ₃ ) SiF ₂ ⁻ and F ⁻ .

In the present invention, the acrylate ester used for copolymerization with the macromonomer has a glass transition temperature of a homopolymer of 0 ° C. or lower, and includes ethyl acrylate, n-butyl acrylate, and hexyl acrylate. , Octyl acrylate, 2,2,2-trifluoroethyl acrylate, 4,4,5,5-tetrafluoro-3-oxapentyl acrylate 2,2,3,3,5,5,5- Heptafluoro-4-oxapentyl and the like can be used alone or in combination of two or more. Among them, n-butyl acrylate is most preferred. When an acrylate ester having a glass transition temperature exceeding 0 ° C. is used, sufficient properties as a comb-type elastomer cannot be obtained, and a comb-shaped resin having excellent impact resistance cannot be obtained.

The composition ratio of the methacrylic macromonomer and the acrylate monomer in the comb elastomer of the present invention is 80 to 40 parts by weight of the acrylate monomer to 20 to 60 parts by weight of the macromonomer. If the proportion of the macromonomer exceeds 60 parts by weight, the flexibility required for the elastomer cannot be obtained, and if it is less than 20 parts by weight, sufficient mechanical strength cannot be obtained.

On the other hand, the composition ratio of the methacrylic macromonomer and the acrylate monomer in the comb resin of the present invention is 40 to 10 parts by weight of the acrylate monomer with respect to 60 to 90 parts by weight of the methacrylic macromonomer.
More preferably, the acrylate monomer is 35 to 10 parts by weight based on 65 to 90 parts by weight of the methacrylic macromonomer. If the proportion of the macromonomer is less than 10% by weight, sufficient impact resistance cannot be obtained, and if the proportion of the macromonomer exceeds the upper limit, the character of the elastomer becomes strong, and the hardness of the comb-type resin becomes high. , Elastic modulus and the like are not preferable.

The acrylic comb copolymer of the present invention can be produced by copolymerizing the methacrylic macromonomer with an acrylate ester. The copolymerization method is easiest and most preferred by radical polymerization. As the method and the polymerization conditions of the radical polymerization, if the method and the conditions are such that the molecular weight in terms of polystyrene corresponding to the peak top of the molecular weight distribution curve measured by the GPC method of the resulting comb copolymer is 50,000 or more. Anything can be adopted. As an example of a preferable polymerization method, a suspension polymerization method using the above-described solvent (the first invention) is mentioned, but is not necessarily limited to this method.

In addition, the polystyrene-equivalent molecular weight corresponding to the peak top of the molecular weight distribution curve of the comb copolymer according to the present invention refers to the reduced molecular weight corresponding to the peak-up of the GPC elution curve measured under the following conditions (in Examples). Will be abbreviated as peak top molecular weight). The value of the number average molecular weight shown in the examples is the number average molecular weight in terms of polystyrene measured under the same conditions.

GPC measurement conditions: Apparatus: 201D compact type (manufactured by Waters) Column: TSK gel GMHXL + 4000HXL + 2500HXL Solvent: tetrahydrofuran Temperature: 30 ° C. Flow rate: 0.7 ml / min Sample concentration: about 1% Detector: Differential refractometer Comb-shaped elastomer of the present invention By blending 5 to 50 parts by weight with respect to 100 parts by weight of the methyl methacrylate polymer, the impact resistance of the methyl methacrylate polymer can be greatly improved.

As used herein, the methyl methacrylate polymer refers to a methyl methacrylate homopolymer or a copolymer of methyl methacrylate and another methacrylate or acrylate, containing at least 70% by weight of methyl methacrylate units. And having a molecular weight comparable to that of a commercially available methacrylate-based molding material.

If the amount is less than 5 parts by weight per 100 parts by weight of the methyl methacrylate polymer, the impact resistance is not sufficiently improved. Also, when the amount is more than 50 parts by weight, heat resistance and the like are lowered, and the inherent characteristics of the methyl methacrylate copolymer are lost.

The mixing of the methyl methacrylate polymer and the comb-shaped elastomer of the present invention is carried out by melt kneading using a Banbury kneader, a roll kneader, a screw kneader, or the like, or after dissolving in a common solvent, and simultaneously precipitation in a poor solution. It can be easily carried out by a method used for mixing ordinary resins, such as a method for causing the resin to mix.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples.

 In the examples, "parts" means parts by weight.

The evaluation of various physical properties in the examples was performed by the following methods.

Tensile modulus, tensile strength at break, and elongation at break are based on JIS K-674.
Compliant with 5. However, the tensile breaking strength is a value divided by the initial sample cross-sectional area.

Light transmittance was based on ASTM D1003. However, the measurement was performed for a sheet having a thickness of 200 μm and a molded plate having a thickness of 3.2 mm.

The weather resistance was evaluated by elongation retention after exposure to a sunshine weatherometer for 2000 hours.

Izod impact strength was evaluated according to ASTM D256 with 1/4 'notch.

The heat distortion temperature was measured under a load of 18.56 kg in accordance with ASTM D648.

Synthesis Example 1 One reaction vessel equipped with an argon inlet, a stirrer, and an exhaust pipe was prepared, and the inside of the reaction vessel was sufficiently purged with argon, and then 300 ml of sufficiently dehydrated tetrahydrofuran and 0.2 ml of trisdimethylaminosulfonium bifluoride. (0.0
4 mol acetonitrile solution) and 5 mmol of vinylphenylketene trimethylsilyl acetal as an initiator were added, and the temperature of the reaction system was set to 0 ° C. with stirring. Next, 0.5 mol of methyl methacrylate was added to the reaction system at a temperature of 30.
The mixture was added dropwise over 20 minutes while being careful not to exceed ℃, and further reacted for 48 hours to complete the polymerization reaction. Then 0.
10 ml of a methanol solution containing 1 mol of hydrochloric acid was added, and the mixture was stirred for 10 minutes to inactivate the growth terminal of the polymer, thereby stopping the reaction.

Next, the macromonomer was recovered by precipitating in hexane and vacuum-dried at a temperature not exceeding 50 ° C. to obtain a white powdery macromonomer. The number average molecular weight of this macromonomer was 10,000 and the molecular weight distribution was 1.2.
In addition, it was confirmed by NMR that one styryl group was introduced per molecule.

Synthesis Examples 2 to 5 Macromonomers having number average molecular weights of 1,000, 5000, 20,000 and 30,000 were synthesized in exactly the same manner as in Synthesis Example 1 except that the amount of the initiator was changed.

Example 1 A powdery polymethyl methacrylate (PMMA) -based macromonomer (AA-6, manufactured by Toa Gosei Chemical Industry Co., Ltd., Mn = 60)
00) 40 parts of methyl ethyl ketone (solubility in water at 20 to 60 ° C. 20 to 30% by weight, hereinafter abbreviated as MEK) is added to a mixed solution of 40 parts of n-butyl acrylate and dissolved. Further, after adding 0.05 part of n-octyl mercaptan to make a uniform solution, 1 part of lauryl peroxide was added as a polymerization initiator, followed by stirring and mixing to prepare a uniform monomer / initiator solution.

A reaction vessel equipped with a stirrer, a cooling pipe and a nitrogen gas introduction pipe was charged with 400 parts of ion exchange, 1 part of a calcium phosphate dispersion stabilizer and 101.05 parts of the above monomer / initiator solution, and the system was sufficiently purged with nitrogen. The temperature of the reaction system was 70
The temperature was raised to ° C. to initiate polymerization. After polymerization at 70 ° C for 3 hours,
The temperature of the reaction system was raised to 90 ° C. over 1 hour, and further maintained at that temperature for 1 hour to complete the polymerization. After the temperature of the reaction system was cooled to 40 ° C., it was separated by filtration, washed, dehydrated, and dried at 70 ° C. overnight to obtain a beaded polymer. The average particle diameter of the obtained polymer was about 100 μm, there was no mutual adhesion of the particles, and the polymer was extremely good as a suspension polymerization particle. The number average molecular weight of this comb copolymer was 95,000, and the molecular weight distribution was 3.5.

Examples 2 to 7 and Comparative Examples 1 to 3 PMMA (branch) -PBuA was carried out in exactly the same manner as in Example 1 except that the solvent shown in Table 1 was used instead of MEK.
A (trunk) comb copolymer was synthesized. The result is first
As shown in the table, the solubility in water is as shown in the examples.
When 10% by weight or more of the solvent was used, good results were obtained, whereas the solubility in water was 10% by weight.
When the dissolution of less than 10% was used, the resulting comb copolymer had a low molecular weight, so that favorable physical properties could not be obtained, and adhesion occurred during polymerization or during drying, so that satisfactory results could not be obtained.

Example 8 Instead of the PMMA-based macromonomer, polystyrene (PS
t) A PSt (branch)-was obtained in exactly the same manner as in Example 1 except that a macromonomer (AS-6, manufactured by Toa Gosei Chemical Industry Co., Ltd., Mn = 6000, reactive group = methacryloyl group) was used. P
A comb copolymer of BuA (stem) was synthesized.

The comb copolymer was obtained in the form of beads having an average particle diameter of about 80 μm, and the molecular weight and the molecular weight distribution were as follows.

Mn = 80000 Mw / Mn = 3.0 Example 9 PMMA (branch) -P3FM was performed in exactly the same manner as in Example 1 except that 2,2,2-trifluorotyl methacrylate (3FM) was used instead of the BuA monomer. A (trunk) comb copolymer was synthesized.

The comb copolymer was obtained in the form of beads having an average particle diameter of about 120 μm, and the molecular weight and the molecular weight distribution were as follows.

Mn = 70000 Mw / Mn = 4.0 Example 10 Instead of a PMMA-based macromonomer, a PBuA-based macromonomer (AB-6, manufactured by Toa Gosei Chemical Industry Co., Ltd., Mn = 6000, reactive group = methacryloyl group) was used. Bu as monomer
A PBuA (branch) -PMMA (trunk) comb copolymer was synthesized in exactly the same manner as in Example 1 except that MMA was used instead of A.

The obtained comb copolymer was obtained in the form of beads having an average particle diameter of about 110 μm, and the molecular weight and the molecular weight distribution were as follows.

Mn = 45000 Mw / Mn = 15 Examples 11 to 13 Combination of PMMA (branch) -PBuA (trunk) was performed in exactly the same manner as in Example except that the amount of MEK used was changed as shown in Table 2. A polymer was synthesized.

The results of the synthesis are as shown in Table 2, and good results were obtained in each case.

Example 14 In the same manner as in Example 1 except that the macromonomer synthesized in Synthesis Example 1 was used instead of AA-6 as the PMMA-based macromonomer, and that n-octyl mercaptan was not used. A PMMA (branch) -PBuA (trunk) comb copolymer was synthesized.

The number average molecular weight of this comb copolymer was 110,000, and the molecular weight distribution was 2.0.

Example 15 PMMA was prepared in the same manner as in Example 1 except that the amount of n-octyl mercaptan used was 0.1 part, and 1 part of azobisibutyronitrile was used instead of lauryl peroxide as a polymerization initiator. A (branch) -PBuA (trunk) comb elastomer was synthesized.

The pick-top molecular weight of this comb elastomer is 25
It was 0000.

After the comb-shaped elastomer was sufficiently dried, it was extruded at a die temperature of 190 ° C. using a small kneading extruder to form a sheet having a thickness of about 0.2 mm, and various physical properties were measured. The measurement results were as follows, and had satisfactory physical properties as an acrylic comb elastomer.

Tensile modulus = 500 kg / cm ² Tensile breaking strength = 100 kg / cm ² Elongation at break = 500% Light transmittance = 95% Weather resistance (elongation retention) = 82% Examples 16 to 19 and Reference Examples 1 and 2 A comb-shaped elastomer was synthesized in the same manner as in Example 15 except that the usage ratio of macromonomer / monomer was changed as shown in Table 3, and a sheet-like material was formed.
Various physical properties were evaluated. When the ratio of the macromonomer / monomer was 30/70 or less, a solvent (MEK) for assisting the dissolution of the macromonomer was not used.

The evaluation results of the various properties are as shown in Table 3. In the case of the sheet of Examples 16 to 19, good results were obtained, whereas in the case of Reference Example 1, the results were as an elastomer. Were insufficient, and in the case of Reference Example 2, the mechanical properties were significantly inferior and were unsuitable as acrylic elastomers.

Examples 20 to 23 and Reference Example 3 A comb-shaped elastomer was synthesized in exactly the same manner as in Example 15 except that the macromonomers having different molecular weights synthesized in Synthesis Examples 1 to 5 were used. Molded,
Various physical properties were evaluated.

The evaluation results of the various properties are as shown in Table 4 and good results were obtained for the sheet-like materials of Examples 20 to 23, whereas in the case of Reference Example 3, the results were Fusing occurred during drying of the shaped elastomer and the sheet could not be evaluated.

Examples 24 to 25 and Reference Example 4 A comb-shaped elastomer was synthesized in exactly the same manner as in Example 15, except that the type of the acrylate monomer used was changed to that shown in Table 5. The sheet was molded and various physical properties were evaluated.

The evaluation results of various properties are as shown in Table 5, and in the case of Reference Example 4, good results were obtained for the sheet-like materials of Examples 24 to 26. Characteristics were insufficient.

Examples 27 to 30 and Reference Examples 5 to 6 Table 6 shows the comb-shaped elastomer synthesized in Example 15 in 100 parts of beaded PMMA resin (Acrypet VHK, trade name, manufactured by Mitsubishi Rayon Co., Ltd.). The mixture was mixed at a ratio and kneaded and extruded with a screw extruder to obtain a pellet-shaped acrylic resin composition. After sufficiently drying the obtained pellets, a test piece for measuring impact strength, a test piece for measuring heat deformation temperature and a thickness for measuring light transmittance by injection molding 3.
A 2 mm plate was formed and various physical properties were evaluated. The evaluation results are shown in Table 6.

Example 31 PMMA was performed in the same manner as in Example 1 except that the proportions of the PMMA-based macromonomer, MEK and n-butyl acrylate were changed to 80 parts, 80 parts and 20 parts, respectively.
A (branch) -PBuA (trunk) comb resin was synthesized.

The pick-top molecular weight of this comb resin was 130,000.

After the comb resin was sufficiently dried, it was pelletized using a screw extruder. Using the pellets, test pieces for measuring various physical properties were molded by injection molding, and the physical properties were evaluated. The results were as follows, and were satisfactory as impact-resistant acrylic resin.

Izod impact strength = 4.2 kg · cm / cm Heat deformation temperature = 91 ° C. Light transmittance = 93% Examples 32 to 34 and Reference Examples 7 to 8 The ratio of macromonomer / monomer used was changed as shown in Table 7. Except for this, a comb-shaped resin was synthesized in exactly the same manner as in Example 31, various test pieces were molded, and various physical properties were evaluated. The evaluation results of the various properties are as shown in Table 7. While good results were obtained for the resins of Examples 32 to 34, in the case of Reference Example 7, the impact resistance was low. In the case of Reference Example 8, the properties are insufficiently improved, and the properties as an elastomer are stronger than those as a hard resin, and the light transmittance is slightly lower.

(Effect of the Invention) According to the method for producing a comb copolymer of the present invention, the ratio of the macromonomer constituting the branch portion of the comb copolymer and the vinyl monomer constituting the trunk portion can be selected in a wide range,
In addition, it has become possible to produce a comb copolymer having a considerably high molecular weight. As a result, the structural range of the combi-formable copolymer can be greatly expanded, and the excellent properties of the comb-type copolymer can be sufficiently received.

According to the present invention, there is provided a novel acrylic elastomer having a comb-shaped copolymer structure which retains the properties of an acrylic elastomer having excellent transparency and weather resistance. This comb copolymer can also be used as an impact resistance modifier by blending it with a methacrylic resin.

Further, according to the present invention, there is provided an acrylic comb copolymer resin which is excellent in impact resistance while maintaining excellent properties of acrylic resin such as transparency, weather resistance and gloss.

Continuation of front page (56) References JP-A-51-125186 (JP, A) JP-A-62-121717 (JP, A) (58) Fields studied (Int. Cl. ⁶ , DB name) C08F 290 / 02 C08F 2/18 C08F 265/00

Claims (1)

(57) [Claims] 1. A number average molecular weight of 30 having a vinyl group at one end.
Mixing a polymer of 00 to 50,000 and a vinyl monomer together with a polymerization initiator in a solvent which is a good solvent for the polymer and is soluble in water at 30 ° C. at 10% by weight or more, and subjecting the mixture to aqueous suspension polymerization. A method for producing a comb copolymer.