JPS6337112A - Production of curable resin - Google Patents

Abstract

PURPOSE:To obtain the titled resin, capable of giving water- and impact-resistant cured articles without using a solvent and useful as coating materials, etc., by copolymerizing an esterification reactive group-containing monomer, etc., by a bulk polymerization method and reacting the resultant copolymer with an unsaturated compound having a functional group capable of esterification reaction with the reactive groups. CONSTITUTION:A mixture of vinyl based monomers containing an ethylenic monomer, e.g. acrylic acid, etc., having an esterification reactive group as at least one component is copolymerized to give a vinyl based copolymer having the reactive groups in the side chain, which is then reacted with an unsaturated compound, e.g. hydroxyethyl methacrylate, etc., having a functional group capable of forming ester bonds at a ratio to provide an amount of the reactive groups in the copolymer equivalent to the functional groups in the unsaturated compound. Thereby the aimed curable resin having unsaturated bonds through ester bonds in the side chain.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention provides a curable resin having an unsaturated group in the side chain via an ester bond, which is useful for various uses such as molding materials, FRP, adhesives, and paints. Relating to a manufacturing method.

[Prior Art] ' Unsaturated polyester resins and vinyl ester resins are typical examples of radical curable resins, and diallyl phthalate resins are also used in molding materials, decorative boards, and the like.

Each of these resins is used according to its features and physical properties and is extremely useful.

On the other hand, even in various applications and when new properties are required, there are many points in which existing drawbacks must be improved.

For example, vinyl ester resin exhibits excellent water resistance and chemical resistance, and is widely used as corrosion-resistant FRP and corrosion-resistant flake lining. It is difficult to obtain at this stage.

That is, depending on the application, if the molecular weight of an oligomer or prepolymer is from several hundred to 2,000, it is difficult to apply it to the production of a molding material or prepreg, and it is necessary to increase the molecular weight by some means.

Therefore, taking the above-mentioned vinyl ester resin as an example, in order to increase the viscosity, it is common practice to use diisocyanate together and react with the hydroxyl groups in the vinyl ester resin to increase the molecular weight. There is.

However, in this method, as a general tendency when using isocyanates, it is difficult to obtain constant viscosity, fluidity, and moldability, and there is considerable variation. Moreover, because it is chemically crosslinked, it tends to be difficult to mold, which is a strong factor preventing its widespread use.

In addition, although the increase in viscosity caused by the formation of metal crosslinks caused by the combination of the carboxyl group at the end of the molecule and the oxide of a divalent metal such as magnesia, which occurs in unsaturated polyester resins, has recently become controllable, the moldability Variations still remain, and the use of alkaline earth metal oxides may be discouraged in applications that require high electrical properties.

[Problem that the invention seeks to solve]

The present invention improves the various drawbacks of the existing resins described above and is one of the curable resins with expanded uses.The present invention is a curable resin that improves the various drawbacks of the existing resins and has expanded uses. Although the vinyl copolymer resin is a curable resin with excellent physical properties such as water resistance and impact resistance, organic solvents are used in part of the reaction process, making recovery and resin purification complicated. The present invention provides a method for producing a curable resin that solves the problems of requiring a large number of steps, inevitably resulting in high costs, and being unfavorable in terms of resin quality control.

[Means for solving problems]

The method for producing a curable resin of the present invention includes copolymerizing a mixture of vinyl monomers containing an ethylene monomer having an esterification reactive group as at least the l component to obtain a vinyl copolymer having the reactive group in the side chain. The resulting vinyl copolymer is then treated with the reaction group 3ψ7. The combination is raw and official.

In a method for producing a curable resin having an unsaturated bond in a side chain via an ester bond, by reacting an unsaturated compound having , the mixture of vinyl monomers has a weight average molecular weight of +i! The above problem was solved by carrying out copolymerization by bulk polymerization until a vinyl copolymer having a molecular weight of 5,000 to 200,000 was obtained.

[For production]

In the method of the present invention, the weight average By copolymerizing by bulk polymerization until a vinyl copolymer with molecules of 15,000 to 200,000 is produced, complicated steps associated with the use of solvents are unnecessary, and even though no solvent is used, We have arrived at a method that is easy to operate and does not cause gelation of the reactants.

Generally speaking, bulk polymerization is a well-known polymerization method for obtaining vinyl polymers. However, bulk polymerization has drawbacks such as the control of heat generation in vinyl polymerization and the inconvenience of handling when the product is a solid. When performing a chemical reaction, it is necessary to use a solvent in the first step in order to avoid the above-mentioned difficulties. Simply applying bulk polymerization to the first stage copolymerization does not solve the aforementioned problems such as difficulty in controlling the reaction, generation of gel, and inconvenience in handling the reaction product.

The method of the present invention produces a copolymer with a lower molecular weight than the molecular weight of the polymer produced in ordinary vinyl polymerization when carrying out bulk polymerization, making it convenient to handle the product, no gel is generated, and bulk polymerization is possible. This is based on the knowledge that it is easy to control the reaction heat and that it is possible to obtain a curable resin with good physical properties.

According to the method of the present invention, since the molecular weight of the vinyl copolymer produced is suppressed to a low molecular weight, the increase in viscosity accompanying an increase in the polymerization rate is small, and there are advantages that bulk polymerization can be carried out easily. The unreacted vinyl monomer can be used as it is as a solvent in the second step, and in the second step, it can be used as a crosslinking agent for the curable resin.
There are advantages.

The molecular weight (weight average) of the vinyl copolymer produced in the first step of the method of the present invention is 5.000 to 200,000.
is adjusted within the range of If the molecular weight is lower than 5,000, the physical properties of the cured resin, especially impact resistance, will be poor, and if the molecular weight is higher than 200,000, the reaction solution will have high viscosity and the product will be inconvenient to handle. This is not desirable.

A vinyl copolymer having such a molecular weight has a reaction temperature of 30 to 2
00°C for 1 to 10 hours, preferably in the presence of a molecular weight regulator.
It is obtained by copolymerizing a mixture of vinyl monomers. Molecular HJI moderating agents that can be used in the method of the present invention include, but are not limited to, methyl mercaptan, ethyl mercaptan, n- or i-pro and lumercabutan,
n-1Sec % or t-butyl mercaptan, n-
or alkyl mercaptans such as i-dodecyl mercaptan, adducts of alkylene oxide and hydrogen sulfide such as ethanethiol and propanethiol, and thiol-based fatty acids such as mercapto group-substituted fatty acids such as 2-mercaptoacetic acid and 2-mercaptopropionic acid. Molecular weight regulators of 0.1 to 5 parts by weight per 100 parts by weight of total monomers are particularly preferred.
It is added in parts by weight.

The copolymerization reaction can be carried out by adding a radical generator commonly used in radical polymerization, but it is better to carry out thermal polymerization without a catalyst by heating only, since there is no residual catalyst in the second step, so the polymerization inhibitor is added. This is advantageous because it acts extremely effectively and prevents gelation.

As the copolymerization reaction progresses, a sample of the reaction solution is taken periodically to measure the molecular weight, and when the desired molecular weight is reached, a polymerization inhibitor and a diluent monomer are added to stop the copolymerization reaction.

The mixture of vinyl monomers used to produce the vinyl copolymer of the present invention must contain an ethylene monomer having an esterification reactive group as at least one component. Here, the esterification reaction group means a functional group that generates an ester bond by reaction with other functional groups such as addition reaction or condensation reaction, and specifically, hydroxyl group, carboxyl group, acid anhydride group, epoxy group. Examples include.

Typical examples of ethylene monomers having esterified anti-tslI= include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, maleic anhydride, and their anhydrides, allyl Alcohol, hydroxyethyl (meth)acrylate,
Unsaturated alcohols such as hydroxypropyl (meth)acrylate, hydroxychloropropyl (meth)acrylate, hydroxyphenoxypropyl (meth)acrylate, hydroxymethylbenzyl (meth)acrylate, N-methylol (meth)acrylamide, allyl glycidyl ether, glycidyl ( meta) acrylate,
Glycidylethyl (meth)acrylate, glycidylpropyl (meth)acrylate, epoxy resin mono (
Examples include unsaturated epoxy compounds such as meth)acrylates.

As the vinyl hexamer to be copolymerized with the ethylene monomer having an esterification reaction group, any type can be used as long as it is copolymerizable with the ethylene monomer.

Typical examples of these include styrene, vinyltoluene, chlorostyrene, methyl acrylate, ethyl acrylate,
Tertiary butyl acrylate, isobutyl acrylate, tertiary butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, methacrylic acid n
-Butyl, isobutyl methacrylate, tertiary butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, tetrahydrofurfuryl methacrylate, acrylonitrile, vinyl acetate, vinyl propionate, vinylidene chloride and chloride Examples include vinyl.

Among these vinyl monomers, styrene, acrylonitrile, acrylic esters, and methacrylic esters are practical, and copolymers of these and mono(meth)acrylates of bisphenol-based epoxy resins have excellent curability to give cured products. It is particularly suitable because it produces resin.

The esterification reaction group introduced into the vinyl copolymer is 0.1 to 10 mol%, more preferably 1 to 5 mol% in the copolymer.
It is adjusted by mixing the ethylene monomer having an esterification reactive group in the vinyl monomer mixture so that the mol% is the same.

The vinyl copolymer obtained in the first step of the present invention is
In the second step, the esterification reaction group present in the side chain is reacted with an unsaturated compound having a functional group that forms an ester bond, thereby curing the side chain to have an unsaturated bond via an ester bond. It is modified into a synthetic resin.

The reaction that produces this ester bond (hereinafter referred to as esterification) is carried out in the presence of a polymerization inhibitor and an esterification catalyst.
It is carried out using conventional esterification operations at temperatures between 0 and 150°C.

It is essential that the unsaturated compound has an esterification reaction group present in the side chain of the vinyl copolymer and a functional group that forms an ester bond, and when a hydroxyl group or an epoxy group is present in the side chain, It is an unsaturated compound having a carboxyl group or an acid anhydride group, and when a carboxyl group or an acid anhydride group is present in the side chain, it has a hydroxyl group or an epoxy group. The unsaturated group of the unsaturated compound is itself or styrene,
Any material that reacts with a common crosslinking agent such as (meth)acrylic acid ester may be used.

Examples of unsaturated compounds that can be used in the method of the present invention include the monomers mentioned above as representative examples of the ethylene monomers, among which acrylic acid and methacrylic acid, which have a (meth)acryloyl group at the molecular end. , hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, glycidyl (meth)acrylate, mono(meth)acrylate of epoxy resin, etc. are particularly useful in terms of the physical properties of the cured product.

The reaction ratio between the vinyl copolymer and the unsaturated compound should be such that the esterification reaction group present in the copolymer and the esterification functional group in the unsaturated compound are substantially equivalent. is preferable, and it is practically acceptable to react in a range of 0.9 to 1.1 equivalents.

Polymerization inhibitors used in the second step include hydroquinone, hydroquinone monomethyl ether, t-butylcatechol, and phenothiazine, while esterification catalysts include tertiary amines, amine salts, quaternary ammonium salts, and metal salts. etc. are preferably used.

The curable resin according to the present invention can be cured by copolymerizing it with a monomer as a monomer solution, and it is also possible to crosslink it by polymerizing the unsaturated bonds of the polymer without using a copolymer.

Representative examples of the above monomers include styrene, vinyltoluene, chlorostyrene, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, tertiary butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, Ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tertiary butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, tetrahydrofurfuryl methacrylate, vinyl acetate and vinyl propionate etc.

Furthermore, the curable resin of the present invention can be used in combination with fillers, reinforcing materials, mold release agents, coloring agents, curing agents, accelerators, stabilizers, etc. as necessary to produce FRP, laminates, adhesives, molding materials, etc. can be widely used.

〔Example〕

Examples will be described below to further specifically explain the present invention. Descriptions in the text are expressed on a weight basis unless otherwise specified.

Example 1 Into 31 autoclaves capable of heating and cooling, butyl acrylate, acrylic acid, t-dodecyl mercaptan (abbreviated as t-DM), n-dodecyl mercaptan (abbreviated as n-DM) were added in the amounts listed in Table 1. (abbreviated)), 120
Copolymerization was carried out at ℃. To monitor the progress of copolymerization, approximately 5 g of sample was periodically taken and the molecular weight was measured. When a predetermined molecular weight was reached, ethylene glycol diacrylate 1- (abbreviated as EGDA) as a diluent monomer, phenothiazine as a polymerization inhibitor, and triphenylphosphine as a catalyst were added in the amounts listed in Table 1, respectively.

Next, an alicyclic epoxy resin having an epoxy equivalent of 142 (manufactured by Union Carbide, trade name ERL-4221) 39
An equivalent amount of an unsaturated epoxy resin that shares an acryloyl group and an epoxy group was added to the molecule obtained by reacting 4 parts with 160 parts of acrylic acid, and an esterification reaction was carried out at 100°C for about 6 hours. .

The viscosity of the resin liquid of the obtained curable resin was 23 voids (25
℃).

A cured product obtained by mixing 100 parts of the curable resin, 1.5 parts of Vercure SA (peroxide catalyst manufactured by NOF ■), and 0.5 parts of cobalt naphthenate (containing 6% cobalt), and curing at room temperature. The physical properties were as listed in Table 1.

Example 2 A curable resin was produced in the same manner as in Example 1, except that the amounts of t- and n-dodecyl mercaptan used as molecular weight regulators were changed as shown in Table 1.

The physical properties of the obtained cured resin were as shown in Table 1.

Comparative Example 1 For comparison with Examples 1 and 2, 5 g of 2,2'-azobisisobutyronitrile (abbreviated as AIBN) was used as a polymerization catalyst without using a molecular weight regulator, and at 70°C. Copolymerization and esterification were carried out in the same manner as in Example 1, except that a copolymer having a molecular weight of 220,000 was produced.

Approximately 50 minutes after starting esterification, the reaction solution turned into a gel, making it impossible to continue the reaction.

(Space below) Examples 3 to 4 and Comparative Example 2 Styrene and epoxy resin monomethacrylate (bisphenol A type epoxy resin with an epoxy equivalent of 185 (manufactured by Shell Chemical Co., Ltd., trade name Epicote 8) were used as copolymerization components.
27) By reaction between 462 parts and 43 parts of methacrylic acid)
Copolymerization was carried out in the same manner as described in Example 1.

Examples were prepared using the formulation and conditions listed in Table 2, except that when the predetermined molecular weight was reached, the copolymerization was stopped using styrene as a diluent, and then esterification was performed using methacrylic acid. Copolymerization and esterification were performed in the same manner as in Example 1.

The obtained resin liquid and its cured product are shown in Table 2.

In the table, the boiling resistance test was performed using a 50X50X2 (wm) plate.
This is the result of measuring the change in weight after boiling in water for 0 hours.

In addition, when copolymerized to a molecular weight of 240,000 using the same method, it gelled in about 20 minutes after starting esterification, making subsequent reactions impossible.

〔Effect of the invention〕

According to the method of the present invention, it is possible to produce a curable resin that does not cause gelation and has an unsaturated group in the side chain via an ester bond without using a solvent, and the resulting resin has water resistance and resistance. Provides a cured product with excellent impact resistance, etc., and can be used for adhesives, paints,
It is useful for various uses such as molded materials, laminates, and FRP.

Claims (3)

[Claims] (1) A mixture of vinyl monomers containing an ethylene monomer having an esterification reactive group as at least one component is copolymerized to produce a vinyl copolymer having the reactive group in the side chain, and then the resulting vinyl A system copolymer is reacted with an unsaturated compound having a functional group that forms an ester bond with the reactive group in a ratio such that the reactive group and the functional group are substantially equivalent, thereby forming an ester in the side chain. In the method for producing a curable resin having an unsaturated bond through a bond, the mixture of vinyl monomers is mixed with a weight average molecular weight of 5.0.
A method for producing a curable resin, characterized in that copolymerization is carried out by bulk polymerization until a vinyl copolymer of 0.00 to 200,000 is obtained. (2) The method for producing a curable resin according to claim 1, wherein the bulk polymerization is carried out in the presence of a molecular weight regulator. (3) The method for producing a curable resin according to claim 1 or 2, wherein the bulk polymerization is carried out without a catalyst.