JPS5928212B2 - Method for producing polymer solution - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing high solids, low viscosity polymer solutions.

Recently, pollution control and resource management have become the most important issues facing the paint industry.

Among these, reducing the amount of organic solvent used is a major problem. Therefore, a high solid type paint was devised in which the solvent content of the conventional solution type paint, which contained a large amount of organic solvent, was significantly reduced. This high solid type paint has
It not only has the advantage of having a small content of organic solvents, but also has the great advantage that conventional solution-type coating technology and equipment can be used as is for coating or coating. Needless to say, in order to produce a high solids type coating material having various advantages as described above, a polymer solution with a high solids content and a low viscosity is required. As is well known, in order to obtain a polymer solution with a high solids content and a low viscosity, the molecular weight of the polymer used must be significantly lowered than in conventional solution-type solutions. However, since it is impossible to produce a high solids solution of such a low molecular weight polymer using conventional polymerization methods, it is necessary to use a large amount of polymerization initiator or chain transfer agent, polymerize at high temperature, or at extremely high temperature. This was carried out using a special method such as polymerization at a low monomer concentration and then removing the solvent.
However, in these methods, a large amount of polymerization initiator,
There were problems in terms of adverse effects on performance due to decomposition products of the chain transfer agent, odor, heat generation control, equipment, boiling point of the solvent used, and complicated operations. Moreover, as mentioned above, by significantly lowering the molecular weight of the polymer, there was a problem in that the resulting coating film was inferior in various properties across the board compared to the case of conventional solution-type coatings. Furthermore, although the technology is not so much related to high solid type paints, the technology related to the manufacturing method of copolymer materials containing this type of itaconic acid dialkyl ester has been known for a long time. No.) As disclosed in the specification etc.

However, in this patent No. 151564,
Although a method for producing a copolymer material comprising an itaconate ester is described, which comprises copolymerizing the itaconate ester and at least one other polymerizable compound containing a CH2=C group. This ethylenically unsaturated bond (CH2-C()) does not correspond to the "functional group" in the present invention, and in that sense, "allyl acrylate" and "Glycol dimethacrylate" and the like are merely examples of ethylenically unsaturated bond-bearing compounds.
In view of the above drawbacks, as a result of intensive research, the present inventor has developed a monomer mixture in which the weight ratio of itaconic acid dialkyl ester and styrene compound is 50 to 90% by weight.
(hereinafter referred to as %), for at least 55 parts by weight (hereinafter referred to as part) of a monomer composition consisting of 10 to 30% of functional group-containing monomer and 0 to 40% of other monomers, at most 4 parts by weight (hereinafter referred to as %),
The method comprises polymerizing the above monomer composition in the presence of 5 parts (100 parts in total) of an organic solvent.

/) According to the Yaru method, a low molecular weight polymer solution with high solid content and low viscosity can be produced without requiring any special operations or treatments, and surprisingly, by combining it with an appropriate curing agent. The solution produces coatings that are almost as good as those produced by conventional solution-based coatings. /
) This effect is achieved due to the use of a mixture of itaconic acid dialkyl ester and styrenic compound in a specific range. The itaconic acid dialkyl ester that can be used in this X is one obtained by reacting 1 mol of itaconic acid component with 2 mol of alcohol component, such as dimethyl itaconate, diethyl itaconate, di-n- Examples include butyl, diisobutyl itaconate, di-2-ethylhexyl itaconate, and these can be used alone or in combination.

Further, as the styrene compound, for example, styrene, alkylstyrene, halogenated styrene, etc. can be used. The amount of these styrene S/type compounds used with itaconic acid dialkyl ester is in a weight ratio of 4:1 to 1:3, more preferably 2:1 to 1:1.5. The amount of these monomer mixtures used is 50 to 90% of the total monomers. Functional group-containing monomers include hydroxyl groups, carboxyl groups,
Polymerizable monomers having functional groups such as epoxy groups, amide groups, isocyanate groups, methylol groups, and alkoxymethyl groups, such as (meth)acrylic acid-
2-hydroxyethyl, 2-hydroxypropyl (meth)acrylate, toluene diisocyanate adduct of these hydroxyl group-containing monomers, hexamethylene diisocyanate adduct, (meth)acrylic acid (methyl)glycidyl ester, (meth)acrylic acid, anhydride Maleic acid, fumaric acid, crotonic acid, itaconic acid, dodecynylsuccinic anhydride, monobutyl fumarate, (meth)acrylic acid amide, N-methylol (meth)acrylamide, N-methoxymethyl (meth)acrylamide, diacetone acrylic Amides, etc., and the amount of these functional group-containing monomers used is 10 to 30% of the total monomers.

Other monomers include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, (
Acrylic esters such as tert-butyl (meth)acrylate, Sec-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, benzyl (meth)acrylate, etc. )
Acrylonitrile, dibutyl fumarate, vinyl chloride, vinylidene chloride, vinyl acetate, vinyl propionate, etc., and the amount of these monomers used ranges from 0 to 40% of the total monomers.
is within the range of By dissolving the above monomer composition in an organic solvent to a monomer concentration of at least 55%, preferably from 60 to 85%, and subjecting it to solution polymerization, a polymer solution with a high solids content and low viscosity can be obtained.

For solution polymerization, no special operations or treatments are required, and conventional operations and treatments may be used as they are. Organic solvents that can be used include, for example, xylene,
Aromatic hydrocarbons such as toluene and ethylbenzene, alicyclic hydrocarbons such as cyclohexane and ethylcyclohexane, aliphatic hydrocarbons such as hexane, heptane, and octane, or mixtures of these hydrocarbons, methyl alcohol, ethyl alcohol, Alcohols such as n-butyl alcohol and IsO-butyl alcohol, acetone, methyl ethyl ketone, methyl isobutyl ketone,
These include ketones such as cyclohexanone, acetate esters such as ethyl acetate, butyl acetate, and butyl cellosolve acetate, and ether alcohols such as ethyl cellosolve and butyl cellosolve.

The amount of these organic solvents used is the total amount including the monomer composition 1
00 parts, preferably in the range of 40 to 15 parts. Initiators that can be used during polymerization include, for example, azo compounds such as azobisisobutyronitrile;
Examples include peroxides such as benzoyl peroxide, di-tert-butyl peroxide, cumene hydroperoxide, and hydrogen peroxide.

The amount used is usually 0.1 parts per 100 parts of the monomer composition.
~10 parts. If necessary, mercaptans such as n-octyl mercaptan and n-dodecyl mercaptan, thioglycolic acid esters such as butyl thioglycolate and 2-ethylhexyl thioglycolate, and allyl compounds such as allyl alcohol may be added. The transfer agent is added in an amount of 0.1 to 1 per 100 parts of the monomer composition.
Needless to say, it can be used within the range of 0 parts. The reaction conditions are usually room temperature to 150°C for 2 to 30 hours, preferably 3 to 20 hours.

In this way, high solids and low viscosity solutions of low molecular weight polymers are obtained.

By combining this solution with an appropriate curing agent, a cured coating film with extremely excellent performance that cannot be expected from its molecular weight can be obtained, making it truly useful for high-solids coatings. When the polymer has a hydroxyl group as a functional group, the curing agent to be combined is, for example, a butylated melamine resin, a partial alcohol adduct of a polyvalent isocyanate such as toluene diisocyanate or hexamethylene diisocyanate, or a curing agent using phenol, oxime, or alcohol thereof. Chemicals, etc. can be used. Further, when the functional group is a carboxyl group, for example, epoxy resin, methoxymethylated acrylamide resin, etc. can be used, and when the functional group is an epoxy group, for example, adipic acid, polyamide resin, carboxyl group-containing polyester resin, etc., and when the functional group is an amide group, for example, In the case of butylated melamine resins and isocyanate groups, for example, hydroxyl group-containing polyester resins, and in the case of methylol groups and alkoxymethyl groups, for example, butylated melamine resins, hydroxyl group-containing polyester resins, etc. can be used. The present invention will be explained below using examples.

In the text, parts refer to parts by weight. Example 1 A reactor equipped with a thermometer, a stirrer and a reflux condenser was
250 parts of butyl acetate, di-T.

Charge 3.25 parts of rt-butyl peroxide,
The mixture was heated to 0° C. and the mixture was added dropwise over 5 hours.

It was further kept at 120℃ for 5 hours, and the non-volatile content was 65.8%.
A solution having a Cardner-Volt viscosity Q was obtained. The number average molecular weight of the polymer was 2,000. Example 2 250 parts of butyl acetate and 3.25 parts of di-tert-butyl peroxide were charged into a reactor equipped with a thermometer, a stirrer, and a reflux condenser and heated to 120°C, and the mixture thereof was heated to 120°C. It dripped over time.

The solution was further maintained at 120° C. for 5 hours to obtain a solution with a nonvolatile content of 65.3% and a Cardner-Volt viscosity of M. The number average molecular weight of the polymer was 1,600. Example 3 250 parts of butyl acetate and 3.25 parts of di-tert-butyl peroxide were charged into a reactor equipped with a thermometer, a stirring device, and a reflux condenser, and the mixture was heated to 120°C. The mixture was added dropwise over 5 hours.

It was further kept at 120℃ for 5 hours, and the non-volatile content was 66.0%.
A solution with a Cardner Bolt viscosity of 1 was obtained. The number average molecular weight of the polymer was 1,900. Example 4 A reactor equipped with a thermometer, a stirrer and a reflux condenser was
250 parts of butyl acetate and 3.25 parts of di-tert-butyl peroxide were charged and heated to 120° C., and a mixed solution thereof was added dropwise over 5 hours.

After another 5 hours at 120'C, the non-volatile content was 65.6%.
, a solution with a Cardner-Volt viscosity G was obtained. The number average molecular weight of the polymer was 1,900. Comparative Example 1 250 parts of butyl acetate and 3.25 parts of di-tert-butyl peroxide were charged into a reactor equipped with a thermometer, a stirring device, and a reflux condenser, and the mixture was heated to 120°C. The mixture was added dropwise over 5 hours.

After keeping it at 120℃ for another 5 hours, the non-volatile content was 65.7%.
A solution with a Cardner Bolt viscosity of V-W was obtained. The number average molecular weight of the polymer was 3,700. Watersol S-616 (methylated melamine resin manufactured by Dainippon Ink & Chemicals Co., Ltd.) and Epiclon 1050 (bisphenol type manufactured by Dainippon Ink & Chemicals Co., Ltd.) were added to each polymer solution of Examples and Comparative Examples. epoxy resin) and P-toluenesulfonic acid 70/20/10/0.5 (solid ratio)
Test 5 of each coating film when mixed in the ratio of The test results are shown in Table 1.

In addition, in order to make a comparison with the invention described in the above-mentioned specification of Patent No. 151564, Comparative Example 2 as described below was prepared.
and Comparative Example 3. Of these, Comparative Example 2 uses ethyl acrylate, and Comparative Example 3 uses this ethyl acrylate and further ethylene glycol dimethacrylate. This is an example of using it instead of a monomer. Comparative Example 2 Except that the entire amount of 2-hydroxyethyl methacrylate, which is a functional group-containing monomer, was replaced with ethyl acrylate.
A control polymer solution was obtained in the same manner as in Example 1, but the nonvolatile content was 65.6%, the Cardner Bolt viscosity was K-L, and the number average molecular weight of this polymer was 1
It was 800.

Comparative example: Methacrylic acid-2-, a monomer containing 3 functional groups
An attempt was made to obtain a control polymer solution in the same manner as in Example 1 except that the entire amount of hydroxyethyl was replaced with ethylene glycol dimethacrylate, but during the dropping of these monomer polymerization initiator mixtures, clogging occurred. Thirty minutes after the start of dropping, the solution became a gel and lost fluidity.

Regarding the polymer solution obtained in Comparative Example 2 above, the coating film was prepared in the same manner as the coating, painting, and baking coating film preparation for each of the polymer solutions obtained in Examples 1 to 4 and Comparative Example 1. Tests were conducted and the results are shown in Table 1.

Claims (1)

[Claims] 1 Monomer mixture 50 in which the weight ratio of itaconic acid dialkyl ester and styrene compound is 4:1 to 1:3
~90% by weight, 10-30% by weight of functional group-containing monomers,
and 0 to 40% by weight of other monomers, in the presence of at most 45 parts by weight (100 parts by weight in total) of an organic solvent, based on at least 55 parts by weight of the monomer composition comprising 0 to 40% by weight of other monomers. A method for producing a polymer solution characterized by: