JPS5833242B2 - Method for producing water-based film-forming substances - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for making butadiene oligomers or copolymers water-soluble, and in particular to a method for producing aqueous film-forming materials.

In recent years, maleated products obtained by addition-reacting maleic anhydride to butadiene low polymers have come into practical use as water-based paints and electrodeposition paints.

However, during the addition reaction of maleic anhydride adducts of butadiene low polymers or low copolymers, the reaction temperature is 150-150°C.
Because the temperature is as high as 250°C, side reactions such as intermolecular crosslinking reactions occur, resulting in a significant increase in viscosity compared to the raw material polymer, making water solubilization extremely difficult and sometimes developing into a gel. be.

This drawback can be prevented by adding an antioxidant, but if a large amount of antioxidant is added, the product will be markedly colored, and a considerable amount of maleic anhydride will remain unreacted, so this should be removed. This creates the problem of having to do something.

Furthermore, since maleic anhydride groups easily react with hydroxyl groups, easily available water-soluble alcoholic solvents cannot be used as maleation reaction solvents or as diluents in the water solubilization step.

Therefore, it is an object of the present invention to provide a method by which butadiene oligomers or copolymers can be made water-soluble without the drawbacks of the conventional methods.

Another object of the present invention is that the drying speed is fast at room temperature and by heating, and the resulting coating film has physical properties such as hardness, abrasion resistance, bending resistance, wearability, chemical resistance, solvent resistance, and surface smoothness. It is an object of the present invention to provide an aqueous coating film-forming material, particularly a coating film-forming material for electrodeposition coating, which has excellent strength and gloss.

The present inventors investigated various methods of introducing into polybutadiene, and found that a compound having a carboxyl group and a mercapto group represented by the general formula (where R represents an organic residue having 1 to 10 carbon atoms) was introduced into polybutadiene. When added, polybutadiene with acid groups that does not easily react with alcoholic solvents is obtained, and the inventors have discovered that this adduct can be made water-soluble with an alkali, and have thus arrived at the present invention.

That is, the present invention provides a butadiene low polymer having a number average molecular weight of 300 to 10,000, a low copolymer containing 50% by weight or less of a copolymer component, or a mixture thereof, with the general formula (wherein R is the above-mentioned An aqueous method characterized by reacting a compound having a carboxyl group and a mercapto group shown in This is a method for producing a coating film-forming substance.

The butadiene low polymer and low copolymer used in the present invention have a number average molecular weight of 300 to 10,000 and are liquid or semisolid at room temperature.

The low copolymer shall contain up to 50% by weight of copolymerized components.

Examples of copolymer components that can be used are isopropylene, 2.3
- Conjugated diolefins other than butadiene, such as dimethylbutadiene and piperylene, vinyl monomers with ethylenic unsaturation, especially aliphatic or aromatic, such as isophthylene, diynebutylene, styrene, alpha-methylstyrene, vinyltoluene, divinylbenzene. It is a vinyl monomer.

A mixture of two or more kinds of a butadiene low polymer and a low copolymer obtained by copolymerizing the above-mentioned copolymer components can also be used.

These low polymers or low copolymers are produced by conventionally known methods.

That is, a typical manufacturing method is anionic polymerization using an alkali metal or an organic alkali metal compound as a catalyst at a temperature of 0°C to 100°C.

The polymers obtained by these methods usually have about 25 to 80% of 1.2 double bonds and about 20 to 75% of 1.4 double bonds.

In this case, in order to control the molecular weight and obtain a light-colored low polymer or low copolymer with a low gel content, an organic alkali metal compound such as benzyl sodium is used as a catalyst, and a compound having an alkylaryl group, such as toluene, is used as a catalyst. Chain transfer polymerization method using as a chain transfer agent (The polymer obtained by this polymerization method usually has about 50 to 75% of 1.2 double bonds and about 20 to 40% of 1.4 double bonds.

) (U.S. Pat. No. 3,789,090) or a living polymerization method using a polycyclic aromatic compound such as naphthalene as an activator and an alkali metal such as sodium as a catalyst in a tetrahydrofuran solvent (Japanese Patent Publication No. 17485, No. 17485, No. 43-1989). No. 27432) (usually containing about 90% of 1.2 double bonds and 10% of .4 double bonds), or using an aromatic hydrocarbon such as toluene or xylene as a solvent, Polymerization method using a metal dispersion as a catalyst and controlling the molecular weight by adding an ether such as dioxane (Japanese Patent Publications No. 32-7446, No. 331245, No. 34-10188) (usually l.2
A suitable manufacturing method is one in which the double bonds are contained in a proportion of 50 to 75%, and the proportions of (1) and 4 double bonds are contained in 10 to 40%.

It is also produced by coordination anionic polymerization catalyzed by an acetylacetonate compound of a group 8 metal such as cobalt or nickel and an alkyl aluminum halide (usually 1.2 double bond traces, 1.4 double bond traces, about 10
Low polymers or low copolymers (contained at a ratio of 0%) (Japanese Patent Publication Nos. 45-507 and 4630300) can also be used.

It is also produced by cationic polymerization at a temperature of 0 to 100°C using a Friedel-Craft catalyst such as aluminum chloride, boron trifluoride, or a complex thereof (usually about 10 to 30% of 1 and 2 double bonds). , 1・
A butadiene-isobutylene low polymerization degree copolymer (containing about 20 to 70% of 4 double bonds) can also be used.

By the polymerization method as exemplified above, the low polymer or low copolymer can be produced by (1) rich in butadiene units with 2 double bonds, rich in butadiene units with 1/4 double bonds, or (2) rich in butadiene units with 1/4 double bonds.
- It is obtained as containing approximately the same amount of both butadiene with 2 double bonds and butadiene with 1.4 double bonds, and either of these can be used in the present invention.

In the present invention, it is also possible to use a polymer obtained by partially oxidizing and polymerizing the butadiene low polymer or low copolymer produced as exemplified above by blowing air into it in the presence of a desiccant such as a naphthenic acid metal salt.

In addition, when producing the above-mentioned low polymers or low copolymers, by adding oxygen-containing compounds such as carbon dioxide, water, alcohol, and organic acids before polymerization termination, it is possible to Polymers or copolymers into which functional groups such as hydroxyl groups and carboxyl groups have been introduced can also be used.

The preferred molecular weight range of the butadiene low polymer or low copolymer used in the present invention is 500 to 5000, more preferably 1000 to 3000, and the preferred range of the content of the copolymer component of the low copolymer is It is in the range of 5 to 30% by weight, more preferably 10 to 25% by weight.

General formula used in the present invention (R is as above.

) Examples of compounds having a carboxyl group and a mercapto group include thioglycolic acid (H8-CH2COOH
), 2-mercaptopropionic acid (H8CH2-CH2
-COOH), α-mercaptopropionic acid (CH3
-CH-CH2-COOH) and mercaptosuccinic acid (
H8-CH-COOH).

☆ In the present invention, the amount of the compound having a carboxyl group and a mercapto group used is not particularly limited, but the acid value of the addition reaction product is 200-20, preferably 100-20.
It is preferable to use it so that it becomes 50.

Generally, the higher the addition rate, the better the solubility of the product in water, but the higher the viscosity of the product.

The reaction between the above butadiene low polymer or low copolymer and the above compound 9 having a carboxyl group and a mercapto group is carried out at a temperature of 20 to 200°C, preferably 50 to 150°C.
The reaction can proceed by contacting at a temperature of .degree.

The reaction is promoted by the presence of oxygen or a radical initiator in the reaction system, but if peroxide 5 is generated in the butadiene polymer, the reaction does not proceed even if a radical initiator is added. Wake up quickly.

The general formula for this reaction is as follows.

Examples of radical initiators that can be used are benzoyl peroxide, cumene hydroperoxide, azobisisobutyronitrile, ditertiary-phthyl peroxide, dicumyl peroxide, and the like.

Although solvents such as benzene, toluene, xylene, cyclohexane, and methyl isobutyl ketone can be used to reduce the viscosity of the reaction system, it is preferable to carry out the reaction in a water-soluble solvent such as butyl cellosolve, isoprobyl cellosolve, diacetone alcohol, etc. This is preferred since it has the advantage that the bath agent can be dissolved in water without being removed after the reaction.

In order to water-solubilize the butadiene low polymer or low copolymer having a carboxyl group synthesized in the present invention, the amount is 0.2 to 2.0 molar equivalent, preferably 0.5 to 1.0 molar equivalent to the carboxyl group. A method of neutralizing with an equivalent amount of a basic compound such as ammonia, amine, or sodium hydroxide can be preferably used.

Water solubilization can be further facilitated by using a small amount of a water-soluble solvent capable of dissolving the resin, such as butyl cellosolve, isobrobyl cellosolve, diacetone alcohol, etc. during water solubilization.

The present invention will be explained in more detail with reference to Examples below.

In the examples, 1.2 and 1. contained in polybutadiene
The proportion of 4 double bonds and corrosion resistance were measured as follows.

(1) Ratio of double bonds Based on MOrerO method using infrared spectrum.

("Koubunshi" Vol. 13, p. 252, 1964) In this measurement method, the sum of both types of double bonds does not necessarily equal 100%.

(2) Corrosion resistance According to JIS-5400, 5% NaCl aqueous solution was sprayed on the cut coating film, and after 300 hours,
Measure the thickest rust width from the cut part.

Example l Number average molecular weight 2000, ■・2 double bonds 65%, ■・4
Polybutadiene 10001 with 30% double bonds, xylene 500P, thioglycolic acid 1751 and 5 g of di-t-butyl peroxide were charged into a 21 separable flask purged with nitrogen, and stirred at 120°C for 2 hours under a nitrogen stream. Heated.

Next, xylene and unreacted thioglycolic acid were distilled off under reduced pressure, and the thioglycolic acid-added polybutadiene 1
173f? I got one.

This produced polybutadienoic acid value is 89-0 (rvKO
H/P), had a hue with a Gardner index of 2, and was very light in color.

The addition reaction rate of thioglycolic acid to polybutadiene was 99% based on the acid value and the yield of the produced polymer, and it is clear that the addition is very easy and in high yield.

This produced polymer 2001 was dissolved in butyl cellosolve 401, and then dissolved in triethylamine 20P and water 5401 to prepare a 25% by weight aqueous solution.

This aqueous solution was milky white and translucent. 61g of titania and 2f of carbon black in the above aqueous solution? of pigment is rolled into three rolls, and then diluted with water to give a solid content concentration of 12% by weight.
An enamel for electrodeposition coating was prepared.

A 3114 treated steel plate manufactured by Japan Test Panel Co., Ltd. was used as a test panel, and a DC voltage of 300 V was applied for 3 minutes to perform electrodeposition coating, followed by baking at 160°C for 30 minutes.
A coating film with a film thickness of 0 micron was obtained.

This coating film had a pencil hardness of 3H, was very hard and had excellent gloss.

Example 2 Number average molecular weight 1020.1・2 double bonds 60%, ■・4
Polybutadiene 4001 with 30% double bonds, xylene 2
001, 6 oz of thioglycolic acid, and 6 g of benzoyl peroxide were placed in a nitrogen-substituted IJ triple flask, heated to 80° C. in a nitrogen stream, and stirred for 2 hours.

Next, unreacted thioglycolic acid and xylene were heated to 120°C.
, 5 mmHg.

The hue of the product is Gardner index 3, and the acid value is 77.0 (
9KOH/P).

Dissolving the above product 101 in butyl cellosolve 21',
After adding cobalt naphthenate tP (cobalt content 6%) to make the mixture uniform, triethylamine 8.5z and water were added to prepare an aqueous solution having a solid content of 30% by weight.

Titania 2 was added to 100S' of the above aqueous solution with a solid content of 30% by weight.
A white water-dispersible paint was prepared by dispersing 0g using a high-speed rotating mixer.

The above paint was applied to a dull steel plate (cold rolled steel plate) using a 5 mil applicator and baked at 120°C for 30 minutes to obtain a coating film with a thickness of 26 microns on the steel plate.

This coating had a pencil hardness of 2H and excellent gloss.

Example 3 Number average molecular weight 2000, ■・2 double bonds 65%, ■・4
Polybutadiene 3001 with 30% double bonds, butyl cellosolve 602, 55 g of thioglycolic acid, and 1.51 g of azobisisobutyronitrile were placed in a 2e separable flask and heated to 90° C. for 2 hours with vigorous stirring.

After cooling the reaction product, triethylamine 36S' and water were added to prepare an aqueous solution having a solid content of 20% by weight.

Titania 311, carbon black 11, and strontium chromate 1f to the above aqueous solution 50oz? The mixture was kneaded with three rolls to be well dispersed, and then diluted with water to have a solid content of 12% by weight to prepare an enamel for electrodeposition paint.

Using a steel plate treated with Bonderite 144 manufactured by Nippon Test Panel Co., Ltd. as an anode, a DC voltage of 320 V was applied for 3 minutes to perform electrodeposition coating, followed by washing with water and baking at 160° C. for 30 minutes.

The resulting coating film had a thickness of 20 μm, a pencil hardness of 3H, a DuPont impact test of 40 CwL, an elixir of 75.5, and a crosscut test, and had very excellent physical properties.

A corrosion resistance test of this coating film was conducted for 200 hours, but almost no rust erosion was observed from the cut portion.

Example 4 Number average molecular weight 1380, hydroxyl value 67.6, ■・2 vinyl content 92%, transt4 bond 8%, O at both ends.
Polybutadiene with H group (N5-PBG manufactured by Nippon Soda)
) 100f, butyl cellosolve 251.2-mercaptopropionic acid 20g, and azobisisobutyronitrile 0.55' were charged into a 1e separable flask,
The mixture was heated to 90° C. for 2 hours with vigorous stirring.

After cooling the reaction mixture, 13.65' of triethylamine and deionized water were added to prepare an aqueous solution having a solid content of 20% by weight.

The above aqueous solution 500P, titania 24.8P, Rikiichi pump rack 0.5? , fine powder aluminum silicate 6.0? 2.0 ml of strontium chromate was stirred vigorously with glass beads for 1 hour using a homomixer to uniformly disperse the mixture.

Next, deionized water was added so that the solid content was 12% by weight to prepare a gray electrodeposition paint.

Using a Bonderite 144 treated steel plate manufactured by Nippon Test Panel Co., Ltd. as an anode, a DC voltage of 270 V was applied for 3 minutes to perform electrodeposition coating, followed by washing with water and baking at 170° C. for 30 minutes.

The obtained coating film had a film thickness of 20 μm, a pencil hardness of 4H, a cross cut pass, a DuPont impact 50 crIL pass, and an Erichsen test of 5.0 mm, and had very excellent coating film physical properties.

Claims (1)

[Scope of Claims] 1. A butadiene low polymer having a number average molecular weight of 300 to 10,000, a low copolymer containing 50% by weight or less of a copolymer component, or a mixture thereof has the general formula (herein R is an organic residue having 1 to 10 carbon atoms) is reacted with a compound having a mercapto group, a carboxyl group is introduced into a part of the butadiene polymer or copolymer silver, and this is converted into a basic compound. A method for producing an aqueous coating film-forming substance, characterized by neutralizing it with