JPS6017367B2 - 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-dispersible resin having the property of being soluble in water or easily dispersible in water.

Water-dispersed resins have been widely used in paints, adhesives, etc. in recent years because they are more favorable in terms of environmental protection, working environment, and resource saving, but they still have various performance issues. At present, it is difficult to say that they are comparable to solvent-based resins.

In particular, in water-dispersed resins obtained by polymerizing a single shot in the presence of an emulsifier, the molecular weight of the polymer is generally extremely large, resulting in poor wetting of the coated surface and coating defects such as pinholes. Therefore, corrosion resistance is not sufficient, and when a low molecular weight emulsifier is used, the emulsifier remains in the film formed by the water-dispersed resin, resulting in poor water resistance, inertia resistance, etc. There is a problem. The present invention has been made in view of the above, and has excellent pigment miscibility, storage stability, and coating workability, as well as a high drying speed and a dry film that has excellent water resistance, corrosion resistance, etc. The purpose is to provide several resins.

The method for producing a water-dispersed resin of the present invention involves polymerizing a radically polymerizable monomer in an organic solvent in the presence of a substrate polymer having at least one group selected from a hydroxyl group, an epoxy group, and an amino group. The resulting functional polymer has the general formula (wherein R represents hydrogen or a methyl group.

) is characterized in that it is esterified and/or amidated with a tetrahydrophthalic anhydride compound, and the modified polymer thus obtained is neutralized with a basic substance. Examples of the substrate polymer having at least one group selected from a hydroxyl group, an epoxy group, and an amino group include hydroxyalkyl (meth)acrylates such as hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylate, diethylene glycol mono(meth)acrylate, etc. ) acrylate, polypropylene glycol mono(meth)acrylate, etc.
One or two functional monomers such as meth)acrylate, N-methylol(meth)acrylamide, allyl alcohol, glycidyl(meth)acrylate, 2-aminoethyl(meth)acrylate, t-butylaminoethyl(meth)acrylate, diallylamine, etc. Polymers containing more than one species as structural units can be mentioned, and preferably,
The above-mentioned functional monomers and ordinary vinyl monomers, that is, monomers and copolymers that do not have a functional group that reacts with the tetrahydrophthalic anhydride compound, are used.

Such ordinary vinyl monomers are not particularly limited, but are preferably methyl (meth)acrylatebutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc.
(meth)acrylic acid alkyl esters such as acrylate, alkenylbenzenes such as styrene, Q-methylstyrene, and vinyltoluene, as well as vinyl acetate, butadiene, acrylonitrile, etc. are used, and (meth)acrylic acid, (meth)acrylic acid, and (meth)acrylic acid are used as necessary. Water-soluble monomers such as acrylamide are also used. Furthermore, polyvinyl alcohol and polyvinyl butyral can also be used as the substrate polymer.

The substrate polymer as described above has a weight average molecular weight of 50
It is preferably in the range of 0 to 100,000, particularly preferably 1,000 to 50,000.

If the weight average molecular weight is less than 500, the resulting water-dispersed resin will have poor water resistance;
If it exceeds 0, when the radically polymerizable monomer is solution-polymerized in the presence of this substrate polymer, or when the functional polymer thus obtained is esterified and/or amidated with a tetrahydrophthalic anhydride compound. This is because the viscosity of the solution is sometimes too high, limiting the amount used, and as a result, the resulting water-dispersed resin lacks stability. To solution polymerize a radically polymerizable monomer in the presence of a substrate polymer,
Any conventionally known method can be adopted. For example, a radically polymerizable monomer and a radical polymerization initiator are added to a solution of an organic solvent containing a substrate polymer, and
All you have to do is heat it to a temperature of 140 qo and roast it.

If necessary, a chain transfer agent may be used in combination. Radically polymerizable monomers are not particularly limited, but examples of odorants include:
(meth)acrylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, glycidyl (meth)acrylate, styrene/Q
-In addition to alkenibenzenes such as methylstyrene and pinyltoluene, vinyl acetate, pinylpyridine, butadiene,
Isoprene, chloroprene, acrylonitrile, etc. can be mentioned, and these can be used alone or as a mixture of two or more.

If necessary, small amounts of (meth)acrylic acid, itaconic acid, (meth)acrylamide, dimethylaminoethyl (meth)acrylate, N-methylol (meth)acrylamide, N-butoxymethyl (meth)acrylate, etc. ) Hydrophilic monomers such as acrylamide, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-acrylamido-2-methylpropanesulfonic acid, and styrenesulfonic acid may be used in combination; , small amounts of ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, neobentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentalythritol A poly(meth)acrylate such as tri(meth)acrylate or a polyfunctional crosslinking agent such as diallyl phthalate may be used in combination. The polymerization solvent for such radically polymerizable monomers may be any organic solvent as long as the polymerization reaction proceeds uniformly in the presence of the substrate polymer, but preferably propanol, butane/- One or a mixture of two or more of water-soluble organic solvents such as cellulose, methyl cellosolve, butyl cellosolve, butyl cellosolve acetate, ethyl carbitol, acetone/methyl ethyl ketone, and ethyl acetate are used. It may contain a small amount of water.

In addition, the radical polymerization initiator is not particularly limited and may be conventionally known such as penzoyl peroxide, t-butyl barpenzoate, di-t-butyl peroxide, cumene hydroperoxide, azobisisobutyronitrile, etc. Any one that exists can be used arbitrarily. If necessary, a chain transfer agent may be used in combination. In the polymerization of the radically polymerizable monomer, the substrate polymer is used in an amount of 5 to 95% by weight, preferably 5 to 6% by weight of the total amount of this polymer and the radically polymerizable monomer.

In this way, the present invention involves polymerizing a radically polymerizable monomer in the presence of a substrate polymer, and modifying the resulting functional polymer by esterifying and/or amidating it with a tetrahydrophthalic anhydride compound. This is a polymer that is neutralized to obtain a water-dispersed resin. Therefore, when the amount of the substrate polymer having hydroxyl groups, etc. is used is too small during the polymerization of radically polymerizable monomers, the obtained water The dispersion resin lacks stability and does not have sufficient air curability based on the tetrahydrophthalic acid ring introduced into the polymer by esterification and/or amidation, while the amount of substrate polymer used is large. If it is too high, the resulting water-dispersed resin will have an excessive amount of hydrophilic groups, which is undesirable because the formed film will have poor water resistance. The functional polymer thus obtained has a weight average molecular weight of 2,000 to 200,000.
It is good that it is within the range of .

When the weight average molecular weight is less than 2,000, the air curing rate of the water-dispersed resin obtained is 4.5 cm, and the film formed by it does not have sufficient initial water resistance; In some cases, the viscosity is too high and painting workability is poor. The functional polymer as described above is reacted with a tetrahydrophthalic anhydride-based compound such as cis-△4-tetrahydro-bran water phthalic acid or cis-3-methyl-△4-tetrahydrophthalic anhydride, and is esterified and/or amidated. Obtain a modified polymer. This esterification and/or amidation can be carried out by conventional methods. For example, the esterification reaction can be carried out by mixing the two and heating to a temperature of 50 to 120°C, if necessary in combination with a solvent, a common esterification catalyst such as benzoic acid or triethylamine, or a polymerization inhibitor such as hydroquinone. , progresses easily. When using a solvent, any solvent can be used, except that solvents having hydroxyl groups or amino groups should be avoided, but the use of water-soluble organic solvents is convenient for operation. In the present invention, as mentioned above, the modified polymer has very active hydrogen at the allylic position of the tetrahydrophthalic acid ring in the side chain, so the film formed by the water-dispersed resin has excellent air-curing properties. In addition, the carboxy group contributes to stabilizing the water-dispersed resin.

From this point of view, tetrahydrophthalic anhydride compounds are
100 parts by weight of polymer (hereinafter, all parts are by weight).
It is preferred to use about 5 to 5 parts of eaves for ) If less than about 5 parts, the resulting water-dispersed resin will not have sufficient air curability, whereas if more than about 5 parts of water-dispersed resin will be used. This is because it lacks stability and has an excessive amount of hydrophilic groups, resulting in a film formed by the water-dispersed resin having poor water resistance after drying. Furthermore, the modified polymer thus obtained preferably has an acid value in the range of about 15 to 120. This acid value is determined by the acid value of the polymer and the amount of tetrahydrophthalic anhydride compound reacted with the polymer, but if the acid value of the modified polymer is less than 5, the resulting water The stability of the dispersion resin is poor, and if it is greater than 100, the hydrophilic groups will be excessive, resulting in poor water resistance of the film formed by the resulting water-dispersed resin. When such a modified polymer is neutralized and diluted with a base and water, a water-dispersed resin according to the present invention is obtained.

Various basic substances can be used without particular limitation, and specific examples include alkali metal hydroxides and carbonates such as lithium hydroxide, potassium hydroxide, sodium hydroxide, and sodium carbonate. , ammonia, triethylamine; good.

The water-retaining resin obtained by the method of the present invention has excellent storage stability, mechanical stability, and pigment miscibility due to the dispersion stability of the polymer modified with the tetrahydrophthalic anhydride compound as described above. This is not only because the hydrogen at the allylic position of the tetrahydrophthalic acid ring in the polymer side chain is extremely active. It has excellent air curing properties and forms a dry film with high water resistance and corrosion resistance.

In addition, when the water-dispersed resin produced by the method of the present invention is used as a paint for room temperature or forced drying, cobalt naphthenate, cobalt naphthenate,
Of course, a metal drying agent such as lead naphthenate may be used, and it may also be used in combination with an amine resin, epoxy resin, etc. as a hardening agent in the baking paint.

The present invention will be explained below with reference to Examples, and the acid value and molecular weight of the polymer, as well as various physical properties of the obtained water-dispersed resin, were evaluated as follows.

'1} Acid value: sample toluenol (9/1)
It was determined by dissolving it in a mixed solvent and performing neutralization titration with a potassium hydroxide ethanol solution for 0.1 day using phenolphthalein as an indicator.

[21 Weight average molecular weight: Determined using a gel permeation chromatography method for a 5% tetrahydrofuran solution of the sample using a GPC-20 mallet machine manufactured by Waters.

t3' Storage stability of water-dispersed resin: After putting a water-dispersed resin with a solid content of 40% in a sample bottle similar to 100 and sealing it, it was left for 7 days at a temperature of 500°C, and no changes in viscosity, phase separation, etc. Observed changes.

■ Physical properties of coating film: 4 pieces of titanium oxide, 0.1 g of cobalt naphthenate, and 0.1 g of lead naphthenate were added to 10 pieces of water-resin with a mass content of 40%, and a paint was prepared by high-speed rotting.

This paint was applied to a zinc-treated steel plate to a film thickness of 40 W, and left to dry at room temperature for one day. Soak the coating in pure water at room temperature for one day and observe whether there are any abnormalities such as rust or blistering. If no abnormalities are observed, the initial water resistance is good. I suppose there is. Further, after coating the paint, it was left alone for 5 days in the same manner as above, and further immersed in pure water for 10 days, and if no abnormality was found, the water resistance was determined to be good. In addition, in the following, when simply mentioning water resistance, initial water resistance shall be included. Next, after applying the paint, it was left at room temperature for 5 days, the dried paint film was cut with cross-cuts that reached the substrate, and left to stand for 7 days in a device that was exposed to 5% saline at a temperature of 35q○. The presence or absence of abnormalities occurring in the coated hardness was observed, and if there were no abnormalities, the corrosion resistance was determined to be good.

Example 1 125 g of butyl cellosolve acetate was placed in a separable flask equipped with a thermometer, a cold tube, and a nitrogen introduction tube.
After purging the inside of the flask with nitrogen, the temperature was raised to 120 qo, and 60 g of butyl methacrylate with dissolved azobisisobutyronitrile spots, 2 females of butyl acrylate and 2 females of 2-hydroxyethyl acrylate were added. A mixed solution of the above was added dropwise over a period of 2 hours, and the mixture was stirred at the same temperature for 3 hours to obtain a butyl cellosolve acetate solution of a substrate polymer having a hydroxyl group.

Next, 9 ml of this solution was put into a 1 x removable flask similar to the above, and after purging the inside of the flask with nitrogen, 12 ml of this solution was added.
The temperature was raised to , and butyl methacrylate 16 in which azopisisobutyronitrile was dissolved was added dropwise over a period of 2 hours, followed by solution polymerization for an additional 3 hours at the same temperature.

After lowering the temperature of the polymer solution thus obtained to 90%, cis-3-methyl-△4-tetrahydrophthalic anhydride 11. Add 0.3 g of triethylamine and 9
The esterification reaction was carried out at a temperature of 0 qo for 3 hours to obtain a colorless and transparent butyl cellosolve acetate solution of the modified polymer.

This polymer had an acid value of 18 and a weight average molecular weight of 8,200. This modified polymer solution contains 10 parts and 0.0 parts of triethylamine. Hammer and pure water99. A male was added and the mixture was neutralized and diluted by high-speed fertilization to obtain a milky white resin with good storage stability.

The paint film prepared from this water-dispersed resin as described above had good water resistance and corrosion resistance. Example 2 In a solution of the substrate polymer obtained in Example 1 in butyl cellosolve acetate, 96 g of styrene and 6 grams of butyl acrylate were polymerized in the same manner as in Example 1.

In the same manner as in Example 1, cis-3-
Methyl-Δ4-tetrahydrophthalic anhydride 11. Tsuru was added and an esterification reaction was carried out to obtain a modified polymer solution, and in the same manner, a water-dispersed resin with good storage stability was obtained. The paint prepared from this water-dispersed resin also formed a film with good water resistance and insect resistance. Example 3 In the same manner as in Example 1, azopisisobutyronitrile 3
Using 4 g of styrene, 2 g of butyl acrylate, and 30 g of diethyl glycol monomethacrylate, 3-
Copolymerization was carried out in 125 g of methoxybutyl acetate to obtain a substrate polymer solution.

Styrene (9) and 2-ethylhexyl acrylate (6) were polymerized using azobisisobutyronitrile in this polymer solution. Cis-3-methyl-A4-tetrahydrophthalic anhydride 1 was added to the thus obtained polymer solution to carry out an esterification reaction to obtain a colorless and transparent modified polymer solution. The solvent was distilled off under reduced pressure, and the residue was dried under reduced pressure at room temperature for 24 hours to obtain a modified polymer having an acid value of 21 and a weight average molecular weight of 12,000. This modified polymer was mixed with 10% dimethylaminoethanol so that the solid content was 40%. The resin was neutralized and diluted with an aqueous solution containing the base material to obtain a water-dispersed resin with good storage stability.

The paint prepared from this moisture-friendly resin also formed a film with good water resistance and insect resistance.

Claims (1)

[Claims] 1. Functionality obtained by polymerizing a radically polymerizable monomer in an organic solvent in the presence of a substrate polymer having at least one group selected from a hydroxyl group, an epoxy group, and an amino group. The polymer is esterified and/or amidated with a tetrahydrophthalic anhydride compound represented by the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R represents hydrogen or a methyl group.) A method for producing a water-dispersed resin, which comprises neutralizing a modified polymer with a basic substance. 2. The method for producing a water-dispersed resin according to claim 1, wherein the substrate polymer contains hydroxyalkyl (meth)acrylate as a structural unit. 3. The method for producing a water-dispersed resin according to claim 1 or 2, wherein the substrate polymer has a weight average molecular weight of 500 to 100,000. 4. The method for producing a water-dispersed resin according to any one of claims 1 to 3, wherein the functional polymer has a weight average molecular weight of 2,000 to 200,000. 5 100 parts by weight of a functional polymer is esterified and/or amidated with about 5 to 50 parts by weight of a tetrahydrophthalic anhydride compound, and the resulting modified polymer has an acid value of about 15 to 120. A method for producing a water-dispersed resin according to any one of claims 1 to 4.