JPS6017361B2 - Method for producing water-dispersed resin - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing a water-dispersed resin.

Moisture warfare resins are more preferable than solvent-based resins in terms of environmental protection, work environment, resource saving, etc., so in recent years they have come to be widely used in paints, adhesives, etc. However, there are still various differences in terms of performance. At present, it is difficult to say that they are comparable to solvent-based resins in this respect.

In particular, in water-dispersed resins obtained by polymerizing monomers in the presence of emulsifiers, the molecular weight of the polymer is generally extremely large, resulting in poor puddles on the surface to be coated, and coatings with pinholes etc. Defects often occur, and therefore, the shipboard resistance is not sufficient. In addition, when a low-molecular-weight emulsifier is used, the emulsifier remains in the film formed by the water-enhanced resin, resulting in poor water resistance. , there are problems with film resistance, etc. The present invention has been made in view of the above, and is an aqueous dispersion that has excellent storage stability and painting workability, has a high drying speed, and provides a dried film with excellent water resistance, corrosion resistance, pigment miscibility, etc. The purpose is to provide resins. In the method for producing a water-dispersed resin of the present invention, a functional vinyl polymer having at least one of a hydroxyl group, an epoxy group, and an amino group is prepared by the general formula (wherein R represents hydrogen or a methyl group).

) A radically polymerizable monoleather is polymerized in the presence of a modified pinyl polymer obtained by esterification and/or amidation with a tetrahydrokeywater phthalic acid compound represented by
This method is characterized by neutralizing this polymer with a base. The functional vinyl polymer is preferably hydroxyalkyl (meth)acrylate such as hydroxyethyl (meth)acrylate or hydroxypropyl (meth)acrylate, or diethylene glycol mono(meth)acrylate.
Acrylate, polypropylene glycol mono(meth)
Polymers containing polyalkylene glycol mo/(meth)acrylate such as acrylate, N-methylol (meth)acrylamide, allyl alcohol, glycidyl (meth)acrylate, aminoethyl (meth)acrylate, diallylamine, etc. as structural units are used. Especially preferably, a copolymer of the above functional vinyl monomer and a normal vinyl monomer is used.

Such vinyl monomers are preferably methyl (meth)acrylate, butyl (meth)acrylate,
(meth) such as 2-ethylhexyl (meth)acrylate
Acrylic acid alkyl esters, anikenylbenzenes such as styrene, Q-methylstyrene, and vinyltoluene, as well as vinyl acetate and acrylonitrile, are used, and if necessary, water-soluble substances such as (meth)acrylic acid and (meth)acrylamide are used. Monosexual abundance is used in combination. Furthermore, polyvinyl butyral and polyvinyl alcohol can also be used as the functional vinyl polymer.

The functional pinyl polymer as described above has a weight average molecular weight of 500 to 100,000, preferably 1,000 to 50,000.
It is good that it is within the range of .

If the weight average molecular weight is less than 500, the film formed by the resulting water-dispersed resin will have poor water resistance;
If it exceeds 000, the viscosity will be too high during esterification and/or amidation in a solvent using a tetrahydrophthalic anhydride compound, and its usage will be limited, and as a result, the resulting water-dispersed resin will become unstable. This is because it lacks sex. A modified vinyl polymer is produced by reacting the above-mentioned government-supplied vinyl polymer with a tetrahydrophthalic anhydride compound such as cis-△4-tetrahydrophthalic anhydride or cis-3-methyl-△4-tetrahydrophthalic anhydride. get. Esterification and/or amidation of the functional vinyl polymer with a tetrahydrophthalic acid compound can be carried out by a conventional method.

For example, the esterification reaction can be carried out by mixing the two, and if necessary using a solvent, a common esterification catalyst such as benzoic acid or triethylamine, or a polymerization inhibitor such as hydroquinone.
If heated to a temperature of 0 to 120°C, the process will proceed easily. It is operationally advantageous to use a water-soluble organic solvent, which will be described later, as the solvent. In the present invention, the modified vinyl polymer imparts air curability to the coating formed by the water-dispersed resin due to the unsaturated double bond of the tetrahydrophthalic acid ring it has in its side chain, and the carpoxylic acid possessed by the modified vinyl polymer The group stabilizes the water-dispersed resin.

From this point of view, tetrahydro-phthalic anhydride compounds are
It is preferred to use about 5 to 5 parts by weight per 10 parts by weight of the functional pinyl polymer. If it is less than about 5 parts, the resulting water-dispersed resin will not have sufficient air curability, while if it is more than about 5 parts, the water-dispersed resin will lack stability and have too many hydrophilic groups. This is because the film formed by the water-dispersed resin becomes inferior in water resistance after drying. Similarly, the modified pinyl polymer preferably has an acid value in the range of about 30-300. This acid value can be determined by selecting the type and quantitative ratio of the modified vinyl monomer and the monomer copolymerized therewith. In the present invention, a radically polymerizable monomer is polymerized by a conventional method in an organic solvent in the presence of such a modified vinyl polymer, and this polymer is neutralized with a base.

The above-mentioned radically polymerizable simple substance is not particularly limited, but specific examples include methyl (meth)acrylate, ethyl (
meth)acrylate, butyl(meth)acrylate, 2
- In addition to (meth)acrylic acid alkyl esters and glycidyl (meth)acrylate such as ethylhexyl (meth)acrylate, alkenylbenzenes such as styrene, Q-methylstyrene, and vinyltoluene, as well as pinyl acetate, vinylpyridine, butadiene, isoprene, Examples include chloroprene, acrylonitrile, methacrylonitrile, and the like. These may be used alone or as a mixture of two or more. If necessary, these monomers may be added with minor amounts of acrylic acid, methacrylic acid, itaconic acid, maleic anhydride, acrylamide, methacrylamide, dimethylaminoethyl methacrylate, N-methylolacrylamide, N-butoxymethylacrylamide, 2 -Hydroxyethyl (
meth)acrylate, 2-hydroxypropyl(meth)
Hydrophilic monomers such as acrylate, 2-acrylamido-2-methylpropanesulfonic acid, and styrene sulfonic acid may be used in combination, and small amounts of ethylene glycol dimethacrylate, tetraethylene glycol diacrylate, butylene glycol Polyacrylates such as dimethacrylate, neobentyl glycol dimethacrylate, trimethylolpropane tri(meth)acrylate, and bentaerythritol tri(meth)acrylate, and polyfunctional crosslinking agents such as diallyl phthalate may be used in combination. Further, the solvent for polymerizing the above radically polymerizable monomer in the presence of the modified pinyl polymer may be any solvent as long as the polymerization reaction proceeds smoothly, but preferably,
One or a mixture of two or more waterborne organic solvents such as propanol, methyl cellosonoleb, butyl cellosolp, butyl cello/rebu acetate, ethyl carbitol, acetone, methyl ethyl ketone, and ethyl acetate are used, and contain a small amount of water. Good too. In addition, the radical polymerization initiator is not particularly limited and may be conventionally known, such as benzoyl peroxide, t-butyl perbenzoate, di-t-butyl peroxide, cumene hydro/gu oxide, azobisisobutyronitrile, etc. The one listed can be used arbitrarily. The amount of the modified pinyl polymer used is about 5 to 95% by weight, preferably about 5 to 6% by weight, based on the total amount of this polymer and the radically polymerizable monomer. If the amount of modified vinyl polymer used is too small, the resulting water-dispersed resin obtained by neutralizing the polymer will lack stability and will not have sufficient air curability. This is because the film formed by this will lack water resistance. The polymer thus obtained has a weight average molecular weight of 2000 to
A value in the range of 100,000 is preferable.

If the weight average molecular weight is less than 2,000, the curing speed of the resulting water-retaining resin will be slow and the film will not have sufficient water resistance, while if it is greater than 100,000, the viscosity will be too high and painting workability will be poor. This is because there are inconveniences such as the need to reduce the resin concentration unnecessarily. The water-dispersed resin of the present invention can be obtained by neutralizing and diluting such a polymer with a base such as ammonia or amine and water.

As the amine, triethanolamine, diethanolamine, dimethylethanolamine, triethanolamine, morpholine, etc. can be used, but the present invention is not limited to these. Furthermore, if necessary, a devassing agent may be added to the water-dispersed resin obtained by the method of the present invention. It not only has storage stability, mechanical stability, and pigment compatibility, but also has air curability due to the air curability of the modified vinyl polymer, and the resulting coating has excellent water resistance.

On the other hand, since the modified vinyl polymer itself is water-repellent, the water-dispersed resin according to the present invention can be uniformly applied to the object to be coated, and the dried film has excellent water resistance as described above. , has no coating defects such as pinholes,
It exhibits excellent corrosion resistance and weather resistance. In addition,
When the water content resin produced by the method of the present invention is used as a paint for room temperature or forced drying, a metal desiccant such as cobalt naphthenate or lead naphthenate may be used, and an amino resin, eboxy resin, etc. may be used as a curing agent. Of course, you can also mix it up and respect it. The present invention will be explained below with reference to Examples.

In addition, in the following examples, the acid value and molecular weight of the polymer,
The various physical properties of the water-dispersed resin and the coating film obtained therefrom were evaluated as follows. '11 Acid value: Determined by dissolving a sample in a toluene/ethanol (9'1) mixed solvent and performing neutralization titration with a 0.1N potassium hydroxide ethanol solution using phenolphthalein as an indicator.

■ Weight average molecular weight: Regarding the 5% tetrahydrolane solution of the sample, it was measured using a Waters GPC-1200 machine.
Determined by gel permeation chromatography.

Storage stability of water-dispersed resin: Put a water resin with a solid content of 40% into a 100' sample bottle, seal it, and leave it for 7 days at a temperature of 500' to prevent viscosity changes, phase separation, etc. Observed changes.

'4) Paint film physical properties: solid content 40% water, 100% resin, 40% titanium oxide, 0.1% cobalt naphthenate, and 0.1% zinc naphthenate added, and coated by high-speed rotation. Prepared.

This coating film was applied to a zinc-treated steel plate to a film thickness of 40 mm, and was allowed to stand at room temperature for 5 days to dry. This coating film was immersed in pure water at room temperature for 10 days, and abnormalities such as rust and blistering were observed. If no abnormalities were observed, the water resistance was determined to be good. The corrosion resistance of the paint film is determined by carving a cross-cut in the paint film that reaches the base material and leaving it in a device that administers 5% saline solution at a temperature of 3 degrees for 7 days to prevent any abnormality that may occur in the paint film. was observed, and if there was no abnormality, the contact resistance was considered to be good. Furthermore, the coating was irradiated with a weatherometer for 250 hours, and abnormalities such as fading and discoloration were observed. If there were no abnormalities, the weather resistance was determined to be good. Example 1 Putyl cellosolve acetate 125 liters was charged into a separate flask equipped with a thermometer, a thermometer, a cooling tube, and a nitrogen introduction tube, and after purging the inside of the flask with nitrogen, the temperature was raised to 120 ° C. 60 parts of butyl methacrylate dissolved in 5 parts of azopisissoptilonitrile, 20 parts of butyl acrylate
A mixed solution of 20 ml and 2-hydroxyethyl acrylate was added dropwise over 2 hours, and the mixture was stirred at the same temperature for 3 hours to obtain a butyl cellosolve acetate solution of a functional vinyl polymer.

Next, after lowering the temperature of this solution to 9 and 0, cis-3-
The functional vinyl polymer was esterified by adding 28.5 parts of methyl-Δ4-tetrahydrophthalic anhydride and 0.3 parts of triethylamine to obtain a solution of the modified vinyl polymer in butyl cellosolve acetate. This polymer has an acid value of 91
, weight average molecular weight was 4,000. 101.4 hours of this modified vinyl polymer solution was charged into a separable flask similar to the above, and after purging the inside of the flask with nitrogen, 120qC
The temperature was raised to .

Next, 160 g of butyl methacrylate dissolved in 6 g of azopisisoptylonitrile was added dropwise over a period of 2 hours, and the mixture was kept at the same temperature for an additional 3 hours to polymerize. 50 g of the butyl cellosolve acetate solution of the polymer thus obtained, 0.4 g of triethylhumine and 49.6 g of pure water were added and heated at high speed to obtain a milky white water-soluble resin with a solid content of 40%.

This water-dispersed resin had good storage stability, and the paint film prepared as described above had good water resistance, corrosion resistance, and film resistance. Example 2 A mixed solution of 96 parts of styrene, 64 parts of butyl acrylate, and 5 parts of azobisisobutyronitrile was added to 101.4 parts of the modified pinyl polymer solution obtained in Example 1, and polymerization was carried out in the same manner as in Example 1. After that, the mixture was neutralized and diluted to obtain a water-dispersed resin with good storage stability.

The paint film prepared from this water-dispersed resin as described above also had good water resistance, corrosion resistance, and weather resistance.

Example 3 In the same manner as in Example 1, azobisisobutyronitrile 3
42 parts of styrene, 28 parts of butyl acrylate, and 30 parts of diethylene glycol monomethacrylate were polymerized in 125 parts of 3-methoxybutyl acetate, and this copolymer was mixed with cis-Δ4-tetrahydrophthalic anhydride. Esterification was carried out using 30 minutes of water to obtain a 3-methoxybutyl acetate solution of the modified vinyl polymer.

This modified pinyl polymer had an acid value of 102 and a weight average molecular weight of 7,800. 100 parts of this modified vinyl polymer solution, 96 parts of styrene, 6 parts of 2-ethylhexyl acrylate
After adding 400 g of azobisisobutyronitrile and 500 g of azobisisobutyronitrile and polymerizing in the same manner as in Example 1, the solid content of this solution was 400 g.
% and diluted with dimethylaminoethanol to obtain a water-dispersed resin with good storage stability. The coating paint prepared from this water-dispersed resin also had good water resistance, weather resistance, and corrosion resistance.

Example 4 In the same manner as in Example 1, styrene 502 and allyl alcohol were copolymerized in 100 g of acetone using 4 g of benzyl peroxide, and then cis-3-methyl was copolymerized using 0.1 g of triethylamine as a catalyst. −△
4-Tetrahydrohydrophthalic acid 10 was esterified.

The solvent was distilled off under reduced pressure, and the residue was dried under reduced pressure at room temperature for 2 hours to obtain a modified polymer with an acid value of 32. This modified polymer 1
60 g of butyl cellosolve was dissolved in 20 g of butyl cellosolve, 60 g of butyl methacrylate, 20 g of phthyl acrylate and 3 g of azobisisobutyronitrile were added thereto, and polymerization was carried out in the same manner as in Example 1.

Claims (1)

[Scope of Claims] 1. A functional vinyl polymer having at least one group among a hydroxyl group, an epoxy group, and an amino group is defined by the general formula ▲mathematical formula,
There are chemical formulas, tables, etc. ▼ (In the formula, R represents hydrogen or a methyl group.) In the presence of a modified vinyl polymer obtained by esterification and/or amidation with a tetrahydrophthalic anhydride compound represented by , polymerizing a radically polymerizable monomer,
A method for producing a water-dispersed resin, which comprises neutralizing this polymer with a base. 2. The method for producing a water-dispersed resin according to claim 1, wherein the functional vinyl polymer contains hydroxyalkyl (meth)acrylate as a structural unit. 3 100 parts by weight of a functional vinyl polymer is esterified and/or amidated with about 5 to 50 parts by weight of a tetrahydrophthalic anhydride compound, and the resulting modified vinyl polymer is about 3 parts by weight.
The method for producing a water-dispersed resin according to claim 1 or 2, wherein the resin has an acid value of 0 to 300. 4
4. The method for producing a water-dispersed resin according to any one of claims 1 to 3, wherein the modified vinyl polymer has a weight average molecular weight of 500 to 100,000.