JP5076323B2 - Method for producing cyclic ether structure-containing (co) polymer and use thereof - Google Patents

Description

The present invention relates to a method capable of efficiently producing a cyclic ether structure-containing (co) polymer while suppressing the formation of gel and the use of the (co) polymer obtained by the method.

Conventionally, various proposals have been made on methods for producing vinyl polymers by polymerizing vinyl monomers such as styrene and acrylic acid esters. Among them, the high-temperature continuous polymerization method in which a vinyl monomer is continuously supplied into a reaction vessel kept at a high temperature to perform radical polymerization can obtain a vinyl polymer in a short time, and can be used as an initiator and chain transfer. It is known as an efficient production method in which a desired molecular weight can be adjusted even with a small amount of the agent (Patent Document 1, Patent Document 2, Patent Document 3).
However, homopolymerization or copolymerization of a vinyl monomer containing a cyclic ether group (hereinafter, homopolymerization and copolymerization are collectively referred to as (co) polymerization, and the homopolymer and copolymer are combined into (co) polymerization. When a high temperature continuous polymerization method is used as described above, a gel-like material is formed on the inner wall and bottom surface of the reactor, and the piping, valves, etc. are closed during long-time production. There is a problem that it becomes impossible to form a gel, and a gel is mixed in the (co) polymer.

Regarding a method for preventing gelation by a high-temperature continuous polymerization method, Patent Document 4 discloses a method for selecting an optimum polymerization solvent. However, in this method, even if it is effective for a hydroxyl group-containing monomer, the (co) polymerization of a cyclic ether group-containing vinyl monomer reacts with the cyclic ether group to form a gel. However, it is possible to increase the compatibility of the polymerization solvent with the (co) polymer and reduce the gel component deposited in the reactor, but the fundamental problem of gel formation has not been solved.

Patent Documents 5 and 6 attempt to reduce gel components by controlling various operating conditions in high-temperature continuous polymerization of epoxy functional acrylic polymers. However, the gel adhesion to the reactor wall and the gelled product in the polymer were not reduced to a satisfactory level, and the effect was still insufficient.

Special Table Sho 57-502171 JP 59-6207 JP 60-215007 Special table hei 10-511992 Special table 2003-505540 Special table 2003-524683

  The problem to be solved by the present invention is that, in the radical high temperature polymerization of a cyclic ether structure-containing (co) polymer, as the proportion of the cyclic ether structure-containing monomer in the total monomer increases, the gel content in the (co) polymer increases. It is to solve the problem that the gel component increases or the gel component adheres to the reactor wall after washing, and to find a polymerization method in which the gel content is difficult to be generated.

As a result of intensive studies in order to solve the above problems, the inventors have made a hydrolysable ester compound in a high-temperature polymerization of a radical polymerizable monomer having a cyclic ether structure-containing vinyl monomer as an essential component. By coexisting, it was found that gel formed in the reactor wall and (co) polymer could be prevented, and the present invention was completed.

That is, the present invention is described below.
[1] A mixture having at least 100 parts by mass of a radical polymerizable monomer having a cyclic ether structure-containing vinyl monomer as an essential component and 1 to 50 parts by mass of trialkyl orthoformate or trialkyl orthoacetate is 150 ° C. to 350 ° C. A method for producing a cyclic ether structure-containing (co) polymer, characterized by polymerizing at a temperature of ° C.
[2] The method for producing a cyclic ether structure-containing copolymer according to [1], wherein the cyclic ether structure-containing vinyl monomer is 5 to 90 parts by mass per 100 parts by mass of the total radical polymerizable monomer.
[ 3 ] The cyclic ether structure-containing (co) polymer according to any one of [1] to [ 2 ], wherein the polymerization method at a temperature of 150 ° C to 350 ° C is a continuous polymerization process using a continuous stirred tank reactor. Manufacturing method.
[ 4 ] The method for producing a cyclic ether structure-containing (co) polymer according to any one of [1] to [ 3 ], wherein the cyclic ether structure-containing vinyl monomer is glycidyl methacrylate.
[ 5 ] A powder coating composition containing the glycidyl methacrylate (co) polymer according to [ 4 ].

According to the production method of the present invention, when a radical polymerizable monomer containing a cyclic ether structure-containing vinyl monomer as an essential component is polymerized at a high temperature of 150 ° C. to 350 ° C., the production of gel is small and The quality of the (co) polymer containing the cyclic ether structure is improved, and the amount of gel adhering to the reaction vessel wall is small, so that the number of washings of the vessel can be reduced, and the productivity of the (co) polymer is improved. Can do.
Moreover, the composition excellent in physical properties, such as surface glossiness, smoothness, and adhesiveness, can be provided by using the (co) polymer of this invention.

The cyclic ether structure-containing vinyl monomer in the present invention is a glycidyl (meth) acrylate having a three-membered ether group, an alkyl glycidyl (meth) acrylate, an epoxycyclohexylmethyl (meth) acrylate, or a four-membered ether. (Meth) acrylic acid esters such as (meth) acrylic acid oxetanyl and 5-membered ring ether (meth) acrylic acid tetrahydrofurfuryl (hereinafter referred to as (meth) acrylic acid in combination with acrylic acid ester and methacrylic acid ester) Non- (meth) acrylic acid esters such as vinyl cyclohexene monooxide and vinyl styrene oxide. (Meth) acrylic acid esters are preferable from the viewpoint of easiness of radical polymerization, and (meth) acrylic acid esters having a three-membered ether group are more preferable in that the cyclic ether structure works as a highly active reactive group. It is most preferable to use glycidyl methacrylate which is inexpensive and easily available (in this application, acrylic and methacryl are referred to as (meth) acrylic).

The monomer in the present invention may be only a cyclic ether structure-containing vinyl monomer, but other monomers capable of radical copolymerization with the monomer may be used in combination. When only the cyclic ether structure-containing vinyl monomer is used, homopolymerization occurs and a cyclic ether structure-containing polymer is produced. When the monomer and another monomer are used in combination, copolymerization is performed, and a cyclic ether structure-containing copolymer is generated.

The other monomer used in the present invention is not particularly limited as long as it has radical polymerizability. For example, styrene, α-methylstyrene, p-methylstyrene, α-methyl-p-methylstyrene, p-methoxystyrene. , O-methoxystyrene, 2,4-dimethylstyrene, chlorostyrene, bromostyrene and other aromatic vinyl monomers, alkyl (meth) acrylates having an alkyl group having 1 to 20 carbon atoms (the alkyl group is (May be linear or branched), polyalkylene glycol (meth) acrylate, alkoxyalkyl (meth) acrylate, hydroxyalkyl (meth) acrylate, dialkylaminoalkyl (meth) acrylate, benzyl (meth) acrylate, Phenoxyalkyl (meth) acrylate, cyclohexyl (meth) acrylate, (meth) acrylic (Meth) acrylic acid esters such as isobornyl acid, alkoxysilylalkyl (meth) acrylate, unsaturated 1,2-substituted carboxylic acid esters such as maleic acid ester, fumaric acid ester, (meth) acrylamide, (meth) acrylic Examples thereof include amides such as dialkylamide, vinyl esters such as vinyl acetate, vinyl ethers, vinyl pyrrolidone and (meth) allyl ethers.

In the present invention, the ratio of the cyclic ether structure-containing vinyl monomer to other vinyl monomers is 1 to 100 parts by mass (100 parts by mass) when the total monomer is 100 parts by mass. In the case of part, it is preferably a homopolymer), more preferably 5 to 90 parts by weight. When the cyclic ether structure-containing vinyl monomer is glycidyl methacrylate, if the monomer exceeds 90 parts by mass, the polymerization reaction rate may decrease due to depolymerization, which may cause problems in productivity. In addition, there is a concern that the amount of gel formation will increase. If it is less than 5 parts by mass, the proportion of the cyclic ether structure-containing vinyl monomer component in the copolymer is small, and the function as a reactive group becomes insufficient. More preferably, it is 10-75 mass parts, More preferably, it is 15-60 mass parts.

The hydrolyzable ester compound in the present invention has a function of reacting with moisture in the reaction system to reduce the moisture concentration. The formation mechanism of the gel generated in the present invention is such that the water taken in from the raw material reacts with the cyclic ether structure in the (co) polymer at a high temperature, the epoxy group opens, and a hydroxyl group appears. It is presumed that the cyclic ether group reacts again to form a crosslinked structure, which accumulates to generate a gel. Since the hydrolyzable ester compound can maintain the moisture in the system at a low concentration, it suppresses the formation of gel.
Examples of the hydrolyzable ester group include orthosilicate ester, orthophosphate ester and orthocarboxylic acid ester. Ortho-carboxylic acid esters are preferred from the standpoint of stability of the compound after hydrolysis and polymerization.

Specific examples of such orthocarboxylic acid esters include trimethyl orthoformate, triethyl orthoformate, tri-n-butyl orthoformate, trimethyl orthoacetate, triethyl orthoacetate, trimethyl orthopropionate, triethyl orthopropionate, trimethyl ortho-n-butyrate. And trimethyl orthoisobutyrate. Dewatering capacity it is necessary to use a trialkyl orthoformate or orthoacetate trialkyl, from the point is large, the speed of the easy availability and dehydration reaction, and more preferably trimethyl orthoformate and trimethyl orthoacetate.

In the present invention, the amount of trialkyl orthoformate or trialkyl orthoacetate should be 1 to 50 parts by mass with respect to 100 parts by mass of the total monomers. When the amount is more than 50 parts by mass, the ratio of the (co) polymer in the polymerization system is lowered and the productivity is deteriorated. When the amount is less than 1 part by mass, the water concentration in the system cannot be reduced, and a gel is easily generated. More preferably, it is 5-30 mass parts.

Further, the amount of trialkyl orthoformate or trialkyl orthoacetate in the present invention protects not only the cyclic ether structure of the monomer but also the cyclic ether structure of the (co) polymer formed during the polymerization from the influence of moisture. There is a need. Therefore, as in high-temperature continuous polymerization, polymerization is performed while continuously supplying the monomer, and the resulting polymer is recovered, and at the same time, the unreacted monomer and hydrolyzed ester compound recovered are added to the polymerization system. In the polymerization method to be recycled, it is necessary to control the total amount of monomer units and monomer units containing a cyclic ether structure contained in the (co) polymer. In such a case, when the total amount is 100 parts by mass, the trialkyl orthoformate or the trialkyl orthoacetate is preferably 1 to 50 parts by mass. When it exceeds 50 parts by mass, the cost is increased. If it is less than 1 part by mass, the moisture concentration cannot be kept low, and gel is generated.

  The molecular weight of the cyclic ether structure-containing (co) weight body of the present invention is preferably 1000 to 100,000 in terms of polystyrene-reduced weight average molecular weight (Mw) by gel permeation chromatography (GPC). If it is less than 1000, the number of cyclic ether structures per molecule decreases, and if it exceeds 100,000, a gel is likely to be generated. From the production and physical properties of various compositions containing a (co) polymer, the preferred Mw is 3000 to 50000, more preferably 5000 to 20000.

In the production method of the present invention, a polymerization solvent may be used. Such a polymerization solvent is not particularly limited, but ketone solvents such as acetone and methyl ethyl ketone, ester solvents such as ethyl acetate and butyl ester, aromatic solvents such as xylene and toluene, hexane, cyclohexane, and liquid paraffin An aliphatic solvent such as
When using said polymerization solvent, 0.1-100 mass parts can be used per 100 mass parts of total monomers. Use of such a polymerization solvent is preferable in that the molecular weight of the (co) polymer can be controlled.

In the present invention, a radical polymerization initiator may be used. Such a polymerization initiator may be any initiator that generates radicals at a predetermined reaction temperature. For example, a peroxide initiator and an azo initiator can be used.
Further, a thermally initiated radical generated from styrene or the like, or dicumyl which decomposes at 210 ° C. to generate a radical may be used. Preferred polymerization initiators include ditertiary butyl peroxide, ditertiary mil peroxide, and ditertiary hexyl peroxide. Azo initiators are more preferred because they are inexpensive and the initiator radicals are less likely to cause hydrogen abstraction.
The amount of the radical polymerization initiator is adjusted according to the molecular weight of the desired (co) polymer, but is preferably 0.001 to 10.0 parts by mass with respect to 100 parts by mass of the total monomers.

The (co) polymerization of the present invention can be any process used in the radical polymerization process. Examples thereof include a batch polymerization method, a semi-batch polymerization method in which raw materials are continuously fed, a tubular continuous polymerization method, and a continuous stirred tank polymerization method (CSTR method). A continuous stirred tank polymerization method (CSTR method) is preferred. This method is excellent in that temperature control can be kept constant and a uniform polymer having a narrow composition distribution and molecular weight distribution can be produced. Specifically, a publicly known method disclosed in Japanese Patent Publication No. 57-502171 (Patent Document 1), Japanese Patent Application Laid-Open Nos. 59-6207 (Patent Document 2), and 60-21.5007 (Patent Document 3) may be used. .

For example, after setting a reactor capable of pressurization to a predetermined temperature under pressure, a monomer mixture consisting of each monomer and, if necessary, a polymerization solvent is supplied to the reactor at a constant supply rate, The method of extracting the polymerization liquid of the quantity corresponding to the supply quantity of a monomer mixture is mentioned. Moreover, a polymerization initiator can also be mix | blended with a monomer mixture as needed. As the compounding quantity in the case of mix | blending, it is preferable that it is 0.001-5 mass parts with respect to 100 mass parts of monomer mixtures. The pressure depends on the reaction temperature, the monomer mixture used and the boiling point of the solvent, and does not affect the reaction, but may be any pressure that can maintain the reaction temperature.

The polymerization temperature for (co) polymerizing the cyclic ether structure-containing vinyl monomer used in the present invention needs to be 150 to 350 ° C. If it exceeds 350 ° C., the (co) polymer may have a problem of coloring or heat deterioration, and a gel is likely to be formed. It becomes wider and requires a large amount of initiator and chain transfer agent to lower the molecular weight, which adversely affects physical properties such as weather resistance, heat resistance and durability. In addition, production problems such as heat removal may occur. Preferably it is 160 to 250 ° C., more preferably 170 to 230 ° C.

In the polymerization carried out at a high temperature, it is preferable to complete the reaction in a relatively short time, and as a process for that purpose, a continuous polymerization process is preferable because it is easier to control.
Therefore, the average residence time in the reactor of the monomer mixture in the continuous polymerization method is preferably 1 to 300 minutes, more preferably 5 to 120 minutes, and most preferably 10 to 40 minutes. If the residence time is less than 1 minute, the monomer may not react sufficiently. If the residence time exceeds 300 minutes, the productivity is poor and the product is exposed to a high temperature for a long time, so coloring and heat deterioration may occur. It can happen and at the same time it is easy to form a gel.

Since the (co) polymer produced by the production method of the present invention has a reactive group introduced, it is useful for various industrial applications. Specific examples include powder paints, compatibilizers, polyester modifiers, chain extenders, adhesion improvers, and adhesives.
In particular, glycidyl methacrylate (co) polymer is suitable for the above applications.

The glycidyl methacrylate (co) polymer obtained by the production method of the present invention has a gel fraction (ratio of gelled product contained in (co) polymer (mass basis)) of 30 ppm or less. Since the conventional manufacturing method is 60 ppm or more, it can reduce to half or less.

The powder coating containing the above glycidyl methacrylate (co) polymer has few gel particles, few defects in the cured coating film, and excellent mechanical properties and durability. Good smoothness of film and high gloss.
The powder coating of the present invention includes the (co) polymer, a curing agent such as dodecanedioic acid, a pigment such as titanium oxide, carbon black, and a petal, a filler such as calcium carbonate, a leveling agent, and fluidity. A well-known thing, such as a regulator and a sclerosing | hardenable regulator, can be mix | blended.
The (co) polymer of the present invention is also suitable for other uses such as polyester chain extenders, polymer alloy compatibilizers, and adhesives.

Examples of the present invention will be described below together with comparative examples, but it goes without saying that the scope of the present invention is not limited to these examples. In the following, “part” is based on mass unless otherwise specified.

<Example 1>
The temperature of the oil jacket of a 1000 mL capacity pressurized stirred tank reactor equipped with an oil jacket was kept at 205 ° C.
72.0 parts of styrene (hereinafter referred to as St) as a monomer, 19.5 parts of glycidyl methacrylate (hereinafter referred to as GMA), 5.8 parts of butyl acrylate (hereinafter referred to as BA), trimethyl orthoacetate (as hydrolyzed ester compound) Hereinafter, a monomer adjusted by a ratio of 1.2 parts of MOA, 1.0 part of methyl ethyl ketone (hereinafter, MEK) as a polymerization solvent, and 0.45 part of ditertiary butyl peroxide (hereinafter, DTBP) as a polymerization initiator. The mixed solution was charged into the raw material tank. The recycle tank was filled with a monomer mixed liquid adjusted at a ratio of 35 parts St, 5 parts GMA, 3 parts BA, 25 parts MOA, and 32 parts MEK.
Supply to the reactor was started simultaneously at a flow rate of 375 g / min for the mixed solution in the raw material tank and 10.5 g / min for the mixed solution in the recycle tank. The reaction mixture was continuously withdrawn from the outlet at a flow rate of 48 g / min corresponding to the supply amount of the monomer mixture while keeping the weight in the reactor at 580 g. The internal temperature of the reactor at that time was maintained at 210 ° C., and the internal pressure was adjusted to 1.2 MPa. Further, the extracted reaction product is continuously supplied to a thin film evaporator maintained at 250 ° C. under reduced pressure of 20 kPa, and the monomer and solvent are distilled off, and about 90% by mass of the distillate recovered by the condenser is obtained. Then, it was continuously returned to the recycling tank and 10% of the distillate was discarded. The average residence time of the reaction solution was 12 minutes.
60 minutes after the temperature became stable after the start of the monomer mixture supply, the reaction liquid collection start point was used, and as a result of continuing the reaction for 1140 minutes, the polymer was obtained at a flow rate of 36 g / min. A polymer was obtained. Moreover, about 90% of the distillate was returned to the recycle tank at a flow rate of 10.5 g / min, and the distillate was discarded at a flow rate of 1.5 g / min. Finally, after the polymerization was completed, N-methylpyrrolidone was flowed into the reactor at a flow rate of 48 g / min for about 36 minutes, and the reactor was washed.

When the distillate was collected after the polymerization and analyzed by gas chromatography, St35.2 parts, GMA 5.2 parts, BA 3.1 parts, MOA 25.4 parts, MEK 22.4 parts, There were 3.4 parts of acetone, 1.8 parts of tertiary butanol, 2.3 parts of methyl acetate, and 1.0 part of methanol. From this result, the total feed composition supplied to the reactor was 7.6 parts MOA, 6.6 parts MEK, 100 parts monomer (St 74.1 parts, GMA 19.2 parts, BA 6.1 parts), It was confirmed that the other components were 2.3 parts and tertiary butanol was 0.4 parts.
From the supplied amount, copolymer acquisition amount, distillate amount and composition, the polymerization rate was 87%, and the composition of the obtained copolymer was St: GMA: BA = 73.8: 19.2: 6 (mass ratio). The weight average molecular weight (Mw) obtained from GPC was 11000, and the number average molecular weight was 4500.
When the reactor was disassembled after washing, no gel-like material was found on the wall. Further, 500 g of the copolymer was dissolved in 2 kg of acetone, filtered through a 0.45 um membrane filter, and the membrane filter was dried and weighed. As a result, the insoluble gel fraction contained in the copolymer was 10 ppm. It was.

<Example 2>
Polymerization was carried out for 20 hours in the same manner as in Example 1, except that the ratio of GMA in the total monomer was 30 parts. The feed composition, polymerization conditions, and results are shown in Table 1. In Example 2 where the amount of GMA was increased, there was no gel-like material on the wall, and the gel fraction in the copolymer was low.
The state of the inner wall of the reactor after polymerization in Example 2 is shown in FIG.

<Example 3>
Polymerization was carried out for 12 hours in the same manner as in Example 1, except that the ratio of GMA in the total monomer was 50 parts. The feed composition, polymerization conditions, and results are shown in Table 1. In Example 3 where the amount of GMA was increased, there was no gel-like material on the wall, and the gel fraction in the copolymer was also low.

<Comparative Example 1-3>
Polymerization was carried out under the same conditions except that MOA in Example 1-3 was replaced with MEK. In the comparative example in which MOA was not added, gel adhesion to the reactor wall was remarkable, and the gel fraction in the copolymer was also high. The results are shown in Table 1, and the inner wall of the reactor after polymerization in Comparative Example 2 is shown in FIG.

Various physical properties in Examples and Comparative Examples were measured by the following methods.
(1) Weight average molecular weight (Mw) and number average molecular weight (Mn) were measured in terms of tetrahydrofuran and polystyrene as an eluent using a gel permeation chromatograph (GPC).
(2) Gel fraction: 500 g of the copolymer was dissolved in 2 kg of acetone, filtered through a 0.45 μm membrane filter, the membrane filter was dried and weighed, and the gel fraction was calculated from the initial filter weight.

<Example 4, comparative example 4>
An acrylic powder coating was prepared using the copolymers produced in Example 2 and Comparative Example 2, and the coating film was evaluated. Table 2 shows an ingredient blending table of the acrylic powder coating.
All the components except the fluidity adjusting powder of Table 2 were blended, this was dry-mixed for 3 minutes with a Henschel mixer, then melt-kneaded at 110 ° C. using a BUSS extruder “PR46”, then cooled and coarsened. Crushed. A fluidity modifier was added to this, dry blended, ground at room temperature with a pin mill, and then classified with a 150 mesh wire mesh to prepare an acrylic powder coating composition.
Subsequently, the performance test of the powder coating was performed. The results are shown in the lower part of Table 2. In addition, the test coating plate to be coated was a 0.8T × 70 × 150 mm zinc phosphate-treated plate as an object to be coated. After coating the powder coating to a thickness of 45 to 55 μm, baking was performed at 180 ° C. for 20 minutes. .
The surface state of the coating film was evaluated by visual observation of smoothness. In Table 2, “◯” indicates good, “Δ” indicates slightly inferior, and “×” indicates inferior.
As shown in Comparative Example 4, small irregularities were observed on the surface of the coating film using the copolymer of Comparative Example 2. On the other hand, as shown in Example 4, no flaws could be visually confirmed in the coating film using the copolymer of Example 2 having a low gel fraction.
When the 60 ° gloss was also measured, the coating film of Example 4 had a higher gloss value than the coating film of Comparative Example 4.
When an accelerated weather resistance test was conducted for 1000 hours with a sunshine weather meter manufactured by Suga Test Instruments Co., Ltd., the 60 ° gloss retention rate of the coating film of Example 4 was higher than that of the coating film of Comparative Example 4.

Details of each component in Table 2 are as follows.
Dodecanedioic acid: DuPont, trade name “Dodecanedioic acid”
Leveling regulator: BASF Corporation, trade name "Acronal 4F"
Calcium carbonate: manufactured by Maruo Calcium Co., Ltd.
Epoxy resin: manufactured by Toto Kasei Co., Ltd., trade name “Epototo YD012”
Carbon black: Product name “MA100” manufactured by Mitsubishi Chemical Corporation
Fluidity adjusting powder: “Aerosil 200” (manufactured by Nippon Aerosil Co., Ltd.)

According to the present invention, it is possible to perform polymerization for a long time without gelation of the total monomer having a cyclic ether structure-containing vinyl monomer as an essential component by a high-temperature continuous polymerization method with good productivity. The (co) polymer obtained by this method is easy to process with little mixing of gelled products. When used as a powder coating composition, it has excellent mechanical strength, durability, smoothness, gloss, and adhesiveness because there are few defects in the coating film. It can also be used for polyester modifiers and adhesives.

2 is a photograph of a reactor after polymerization in Example 2. 2 is a photograph of a reactor after polymerization in Comparative Example 2.

Claims (5)

A mixture having at least 100 parts by mass of a radically polymerizable monomer having a cyclic ether structure-containing vinyl monomer as an essential component and 1 to 50 parts by mass of trialkyl orthoformate or trialkyl orthoacetate is a temperature of 150 ° C. to 350 ° C. A method for producing a cyclic ether structure-containing (co) polymer, characterized in that the polymerization is carried out with The method for producing a cyclic ether structure-containing copolymer according to claim 1, wherein the cyclic ether structure-containing vinyl monomer is 5 to 90 parts by mass per 100 parts by mass of the total radical polymerizable monomer. The method for producing a cyclic ether structure-containing (co) polymer according to any one of claims 1 to 2 , wherein the method of polymerizing at a temperature of 150 ° C to 350 ° C is a continuous polymerization process using a continuous stirred tank reactor. The method for producing a cyclic ether structure-containing (co) polymer according to any one of claims 1 to 3 , wherein the cyclic ether structure-containing vinyl monomer is glycidyl methacrylate. A powder coating composition comprising the glycidyl methacrylate (co) polymer according to claim 4 .