JPH03182543A - Aqueous resin composition - Google Patents

Abstract

PURPOSE:To improve the curability, resistance to water and chemicals, and gloss by co-condensing an alkyl-etherified benzoguanamine resin with a hydrophilicity imparting compd. and then making the resulting product soluble or dispersible in water. CONSTITUTION:100 pts.wt. (solid base) alkyl-etherified benzoguanamine resin is co-condensed with 10-100 pts.wt. (solid based) hydrophilicity imparting compd. comprising a compd. contg. both a hydroxyl group and a polyoxyethylene part or a compd. or resin contg. both a hydroxyl group and an acidic group such as a carboxyl, sulfoxyl, or phosphoric group in the molecule, if necessary in an org. solvent contg. water, at 60-100 deg.C. An aq. medium comprising water and, if necessary, contg. is added to the compound and org. solvent, the org. solvent is removed from the product in a vacuum to make the co-condensate soluble or dispersible in water, thus giving the title compsn. contg. a crosslinker and comprising an alkyl-etherified benzoguanamine resin soluble or dispersible in water. The compsn, if necessary, is compounded with a film-forming resin soluble and/or dispersible in water.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a new and useful aqueous resin composition.

More specifically, the present invention provides an aqueous aqueous resin containing an alkyl etherified penzoguanamine IFM resin, particularly a crosslinking agent obtained by cocondensing the penzoguanamine resin with a specific compound to make it water-solubilized or water-dispersed. The present invention relates to a resin composition.

The aqueous resin composition of the present invention can be used for paints, etc.
It can be used in a wide range of applications, including water-based inks, adhesives, and sealants.

(Prior art) In recent years, from the perspective of environmental protection, there has been a demand for reducing the amount of organic solvents emitted during the painting process, and for this reason, it has been necessary to convert conventional solvent-based paints to water-based paints. is being accomplished at a rapid pace.

By the way, methyl etherified melamine resin is generally used as a crosslinking agent for such water-based paints.

However, as long as this type of crosslinking agent is used, a film with satisfactory performance cannot be obtained because the cured film has insufficient water resistance, chemical resistance and gloss.

[Problems to be Solved by the Invention] As described above, as long as the conventional techniques are followed, water-based paints are inferior, and there are limits to the development of water-based resin compositions.

Therefore, the present inventors have keenly realized that in order to improve the coating performance required for such water-based resin compositions, especially water-based paints, an alkyl etherified benzoguanamine resin should be used as a crosslinking agent. So, I started research on a single series.

However, since this alkyl etherified benzoguanamine resin itself is insoluble in water, the development of the aqueous resin and the compound acid has been difficult.

Therefore, the problem to be solved by the present invention is basically an extremely useful alkyl etherified benzoguanamine resin that has excellent curability, water resistance, chemical resistance, and gloss. An object of the present invention is to provide an aqueous resin composition containing a water-solubilized or water-dispersed product.

[Means to solve the problem]

The present inventors therefore took drastic measures to solve the unresolved problems in the prior art as described above, and at the same time, focused on the problems to be solved by the invention as described above, and conducted repeated studies. As a result, a specific compound that has a reactive group and also has the ability to dissolve in water was co-condensed with an alkyl etherified benzoguanamine resin by heating in an organic solvent, and then water was added and hand,
The present invention was completed by discovering that a water-solubilized or water-dispersed product of the benzoguanamine resin can be easily obtained by removing the solvent.

That is, the present invention basically provides an aqueous resin composition containing a water-soluble or water-dispersed alkyl etherified benzoguanamine resin.

Specifically, the alkyl etherified benzoguanamine resin is treated with a compound having a reactive group and also having the ability to dissolve water (hereinafter also referred to as a hydrophilicity-imparting compound).

) and water-solubilized or water-dispersed.

Here, the water-solubilized product or water-dispersed product of the alkyl etherified benzoguanamine resin mentioned above refers to various alkyl etherified benzoguanamine resins (b-1) as listed below, which have various hydrophilic properties as listed below. It refers to a product obtained by cocondensing with compound (b-2) by the method described below, and then making it water-solubilized or water-dispersed by a conventional method.

That is, such a cocondensation reaction is usually carried out in an organic solvent such as a ketone solvent such as methyl ethyl ketone or methyl isobutyl ketone; or a lower C4 or lower alcohol solvent such as methanol, ethanol, isopropanol or n-butanol. Alternatively, if necessary, in a system that also contains water, under heating, usually 60
~100°C, preferably 80-100°C
It is carried out by heating within a range of °C.

The alkyl etherified benzoguanamine resin (b
-1) Examples include methyl etherified penzoguanamine, n-butyl etherified penzoguanamine, isobutyl etherified benzoguanamine, and n-butyl/methyl co-etherified penzoguana straw. These are methylolbenzoguanamines etherified with lower alcohols CI to C4, which are insoluble in water.

On the other hand, only typical examples of the hydrophilicity-imparting compound (b-2) include compounds having both a hydroxyl group and a polyoxyethylene moiety in the molecule, or a hydroxyl group and a carboxyl group or a sulfoxyl group. and compounds or resins having an acid group such as a phosphoric acid group in the molecule.

Among them, first, to mention only the most representative compounds having both a hydroxyl group and a polyoxyethylene moiety, various aliphatic glycol ethers such as ethylene glycol, diethylene glycol, triethylene glycol, or polyethylene glycol; or various aromatic glycol ethers such as ethylene oxide adducts of bisphenol A, which are themselves readily soluble in water.

Next, to mention only typical compounds having both a hydroxyl group and an acid group, (various oxyacids such as citric acid, malic acid, tartaric acid, lactic acid, or dimethylolpropionic acid; Polyesters obtained by condensation polymerization using oxyacids such as
Various hydroxyl group-containing (meth)acrylic acid esters such as meth)acrylates, hydroxyl group-containing vinyl ethers such as 2-hydroxyethyl vinyl ether, or groups that can be converted to hydroxyl groups by hydrolysis, such as vinyltrimethoxysilane. on the other hand, carboxyl group-containing vinyl monomers such as (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid or fumaric acid; (meth)acrylic anhydride, itaconic anhydride or maleic anhydride; Vinyl monomers containing an acid anhydride group such as; vinyl monomers containing a sulfoxy group (sulfonic acid group) such as 2-acrylamido-2-methylpropanesulfonic acid; or vinyl monomers containing a phosphoric acid group such as methacryloyloxyethyl acid phosphate. various acid group-containing monomers,
Further, resins such as vinyl copolymers can be obtained by addition polymerization using other known and commonly used copolymerizable monomers in a conventional manner.

Thus, when the resulting co-condensation reaction product is obtained from a compound or resin having an acid group such as a carboxyl group, various known and commonly used basic compounds such as ammonia, triethylamine or dimethylaminoethanol may be used. After neutralization, on the other hand, in the case of a compound or resin having a polyoxyethylene moiety, after the co-condensation reaction, water or water and ketones are added as necessary. Alternatively, a so-called aqueous medium consisting of an organic solvent such as an alcohol may be added, and the organic solvent may be removed from the system under reduced pressure to make the crosslinking agent of the present invention water-soluble or water-dispersible. (B) will be prepared.

In this case, the water-insoluble alkyl etherified benzoguana fruit resin (b-1) has the above-mentioned reactive group as a hydrophilicity-imparting compound, such as a carboxyl group or a hydroxyl group, and has a water solubility. Compounds that also have (
The ratio of the latter compound (b-2) to 100 parts by weight of the former resin (b-1) in terms of solid content weight ratio is as follows:
b-2) is within a suitable range of about 10 to 100 parts by weight.

If the amount of the hydrophilicity-imparting compound (b-2) used is much less than about 10 parts by weight, it becomes difficult to make the hydrophobic alkyl etherified penzoguana resin (b-1) water-soluble. Therefore, during water dispersion, two-layer separation may occur over time, or
The average particle size tends to increase, and as a result, the storage stability of the resulting aqueous resin composition cannot be ensured, and -
On the other hand, if the amount exceeds about 100 parts by weight,
Inevitably, the curability of the resulting aqueous resin composition tends to decrease, and in extreme cases, when using a compound (b-2) with an average molecular weight of less than 4.000, unreacted components may be removed. Either case is unfavorable, since this tends to increase the amount of water, which ultimately has an adverse effect on the film performance of the resulting aqueous resin composition.

On the other hand, a water-soluble and/or water-dispersible film-forming resin (A ) can, of course, be used as long as it reacts with the crosslinking agent (B) to form a crosslinked cured film and can itself be water-solubilized or water-dispersible. To exemplify only particularly representative examples, polyesters having acid groups such as carboxyl groups, sulfoxyl groups or phosphoric acid groups, preferably carboxyl groups, vinyl resins, vinyl-modified polyesters, A so-called acid group-containing resin such as a vinyl-modified alkyd is neutralized with a basic substance to make it water-soluble; the degree of neutralization is appropriately adjusted to make it water-dispersed; or polyoxyethylene nonylphenyl Including nonionic surfactants such as ethers and anionic surfactants such as polyoxyethylene alkyl allyl ether sulfate salts, polyether side chains having a number average molecular weight of 1.000 to 4.000, Alternatively, in the presence of various known and commonly used dispersion stabilizers such as water-soluble resins such as vinyl resins having an acid value of about 50 to 150, vinyl monomers and other copolymerizable monomers are added, if necessary, to divinyl The average particle diameter is 0.0, which is obtained by polymerizing various known and commonly used crosslinking monomers such as benzene, allyl methacrylate or ethylene glycol di(meth)acrylate.
These include water dispersions of about 5 to 1 μm, and further include water-soluble melamine resins such as hexamethoxymethylolmelamine.

The aqueous resin composition of the present invention comprises a cross-linked water-soluble and/or water-dispersible film-forming resin (A) and a water-solubilized or water-dispersed product of an alkyl etherified benzoguanamine resin, respectively, as described above. agent (B) and
It is advisable to include it as an essential ingredient, and if necessary,
It is made by adding various known and commonly used additives such as a surface smoothing agent, a dispersant, a tackifying agent, an antifoaming agent, or a pigment, and the film-forming resin (A) and the crosslinking agent (B) are combined with each other. The usage ratio of (A)/(B'') = 40 to 90
/60 to 10 (weight part ratio), preferably (A)/(B
) -50 to 80150 to 20 (weight part ratio) is appropriate.

If the amount of component (A) is less than 40 parts by weight, it is impossible to improve processability, and if it exceeds 90 parts by weight, the water resistance of the film will inevitably deteriorate. Both cases are undesirable because they tend to become .

The aqueous resin composition of the present invention thus obtained can be used in a wide range of applications such as paints, water-based inks, adhesives, and sealants, among others.
It can be used as a top coating paint for the outside surface of a can, or in a form mixed with pigment, as a base material for the outside surface of a can, or as a general baking paint.

The coating method is most preferably a roll coating method, but it is also possible to use an air spray coating method, an airless spray coating method, an electrostatic spray coating method, a dipping coating method, an electrodeposition coating method, or the like.

The aqueous resin composition of the present invention usually has a temperature of 150 to 250''C.
By baking at a temperature of 5 seconds to 20 minutes, a cured coating film with excellent performance is formed.

〔Effect of the invention〕

The aqueous resin composition of the present invention obtained as described above has excellent curability, as well as excellent water resistance, chemical resistance, and gloss, and is extremely useful.

In addition, the composition of the present invention itself has good dispersion stability and storage stability.

As described above, the present invention has established a technology for water-solubilizing or water-dispersing alkyl etherified benzoguanamine resin, which is in itself water-insoluble, and has been considered difficult to apply to water-based paints. The effect is great.

〔Example〕

Next, the present invention will be explained by reference examples, examples, and comparative examples.
- Layers, specifically explained. In the following, all parts and percentages are based on weight unless otherwise specified.

Reference Example 1 [Preparation example of water-soluble film-forming resin (A)] 4i! equipped with a stirrer, a temperature control device, a nitrogen gas introduction tube, a condenser, and a pressure reduction device. , were charged with 500 parts of isopropanol (IPA) and 500 parts of methyl ethyl ketone (MEK) and heated to 80°C, and then added thereto with 100 parts of styrene, 390 parts of methyl methacrylate, and n-butyl. A mixture consisting of 200 parts of acrylate, 130 parts of β-hydroxyethyl methacrylate, 80 parts of methacrylic acid, and 20 parts of t-butyl peroxyoctoate was added dropwise over 4 hours, and the temperature was maintained at the same temperature even after the addition was completed. The reaction was allowed to continue for 8 hours.

80 parts of dimethylethanolamine and 100 parts of deionized water are then added, followed by removal of the IPA and MEK under reduced pressure while heating to 60-80°C to obtain a 50% non-volatile and aqueous medium. The composition of water/IPA/MEK
= 89/615, and the weight average molecular weight is 18.0
An aqueous solution of vinyl copolymer resin 00 was obtained. Hereinafter, this will be abbreviated as resin (A-1).

Reference Example 2 [Preparation example of water-dispersible film-forming resin (A)] In a reaction vessel similar to Reference Example 1, methanol (MeOH) was added.
500 parts of MEK, 500 parts of MEK, and 70 parts of a compound represented by the formula % (1) whose polyoxyethylene moiety has an average molecular weight of 4,000, and 8
The temperature was raised to 0°C, and 30% of n-butyl acrylate was added thereto.
0 parts, 300 parts of styrene, 2 parts of methyl methacrylate
70 parts, 130 parts of β-hydroxyethyl methacrylate
A mixture of 1.5 parts and 20 parts of azobisisobutylnitrile was added dropwise over 4 hours, and even after the addition was completed, the reaction was continued by maintaining the same temperature for 8 hours.

Next, deionized water was gradually added, thoroughly stirred, and MeOH and MEK were removed under reduced pressure until the nonvolatile content was 41%.
．． An aqueous dispersion of a vinyl copolymer resin having a concentration of 4% and a viscosity of 22,000 at 25° C. was obtained. Hereinafter, this will be abbreviated as resin (A-2).

Reference Example 3 [Preparation example of alkyl etherified benzoguanamine resin (b-1)] Equipped with a thermometer, a stirrer, and a cooling pipe for removing water 27
! Add butyl alcohol (BuOH) to the four-eye flask.
370 parts (5 moles) of 80% rose formaldehyde, 112.5 parts (3 moles) of 80% rose formaldehyde, 187 parts (1 mole) of penzoquanamine, and 0.3 parts of formic acid were charged, and the temperature was raised over 1 hour. A reflux condition was established.

Next, the reaction was carried out under this reflux condition for 4 hours, and then excess BuOH was distilled off at 70 to 80°C under reduced pressure to make the nonvolatile content 60%.

The aqueous dispersion of alkyl etherified benzoguanamine resin thus obtained had a nonvolatile content of 60.2% and 2%
Gardner viscosity at 5°C was H. Hereinafter, this will be abbreviated as resin (b-1-1).

Reference Example 4 [Preparation example of water dispersion (B) of alkyl etherified benzoguanamine resin] In the same reaction vessel as in Reference Example 1, 500 parts of IPA and 500 parts of MEK were charged, and the temperature was raised to 80 ° C. from,
100 parts of styrene, 390 parts of methyl methacrylate, 300 parts of n-butyl acrylate, 130 parts of β-hydroxyethyl methacrylate, 80 parts of methacrylic acid.
and t-butyl peroxydioquatate were added dropwise over 4 hours, and after the dropwise addition was completed, the same temperature was maintained for 8 hours to continue the reaction, resulting in a non-volatile content of 50.4%. Then, the Gardner viscosity at 25°C is Z
An aqueous solution of a dispersing vinyl copolymer resin having a weight average molecular weight of 17.000 was obtained.

Next, 40 parts of this dispersion resin and resin (b-1-1
) was charged into a 11-size colben equipped with a stirrer, a temperature control device, a decanter, and a nitrogen gas inlet tube, and heated and stirred at 80"C for 2 hours, and the viscosity was Z. It rose from Z to -Z.

Thereafter, a solution consisting of 8 parts of dimethylethanolamine, 66 parts of deionized water, and 26 parts of IPA was added to 15
After dripping for several minutes, remove the IPA using a decanter.
and MEK removed, the non-volatile content was 50.0% and the Gardner viscosity at 25°C was 2. The desired water dispersion was obtained. Hereinafter, this will be abbreviated as resin dispersion (B-1).

Reference Example 5 (same as above) In a glass reaction vessel 21 having the same structure as Reference Example 4, 69 parts of trimethylolpropane, 297 parts of neopentyl glycol, 91 parts of hydrogenated bisphenol A, and 201 parts of isophthalic acid were added. , 1 of tetrahydrophthalic anhydride
86 parts of trimellitic anhydride, 155 parts of xylene, and 10 parts of xylene were charged, the temperature was raised with stirring, the reaction temperature was maintained at 180 to 210"C, and while removing the water produced from the system, The reaction was allowed to continue for a period of time until the acid value reached 55.
, the hydroxyl value is 100, and the number average molecular weight is 1.5
A polyester resin named 00 was obtained.

Next, in a reaction vessel similar to Reference Example 4, 20 parts of this polyester resin and 133.34 parts of resin (b-1-1) were added.
1, 50 parts of MEK, and 50 parts of IPA were charged, and the temperature was raised to 80°C with stirring, and the reaction was carried out by maintaining the same temperature for 2 hours.

Then, after cooling to 50'C, 1.5 parts of dimethylethanolamine, 66.7 parts of deionized water and 31.8 parts of IPA were added dropwise over 15 minutes.
MEK and IPA were removed and the non-volatile content was reduced to 50.
3% and Gardner viscosity at 25°C is 2. The desired water dispersion was obtained. Hereinafter, this resin dispersion (B
-2).

Examples 1 to 4 and Comparative Examples 1 to 3 Water-based varnishes were prepared by blending and mixing at the blending ratios shown in Table 1.

Next, each water-based varnish was applied wet-on-wet to a tin plate with a thickness of 0.24 mm, which had been previously printed with an oil-based alkyd resin printing ink, until the dry film thickness was determined. After coating to a thickness of 10 μm,
Each cured coating was obtained by baking at 180''C for 10 minutes.

Various performance evaluations were performed on the water-based varnish and cured coating film thus obtained. The results are shown in Table 1.

The evaluation criteria for each performance are as follows.

◎...No abnormalities △...Abnormalities observed, questionable for practical use ×・
As is clear from Table 1, the aqueous resin composition of the present invention is obtained using a specific crosslinking agent called a water-solubilized or water-dispersed alkyl etherified penzoguan ξane resin. It is known that it has excellent curability, and the coating film has excellent gloss, water resistance, and chemical resistance, and is extremely useful.

Claims (1)

[Scope of Claims] 1. An aqueous resin composition comprising a water-soluble or water-dispersed alkyl etherified benzoguanamine resin. 2. An aqueous resin comprising a crosslinking agent obtained by co-condensing an alkyl etherified benzoguanamine resin with a compound having a reactive group and also having water solubility to make it water-solubilized or water-dispersed. Composition. 3. Water-soluble and/or water-dispersible film-forming resin (
A) and alkyl etherified benzoguanamine resin (b)
A crosslinking agent (B) obtained by co-condensing -1) with a compound (b-2) having a reactive group and also having water solubility to make it water-solubilized or water-dispersible. An aqueous resin composition comprising: 4. Water-soluble and/or water-dispersible film-forming resin (
40 to 90 parts by weight of A) and the alkyl etherified benzoguanamine resin (b-1), having a reactive group, and
An aqueous resin composition comprising 60 to 10 parts by weight of a crosslinking agent (B) obtained by cocondensing with a compound (b-2) that also has water solubility to make it water-soluble or water-dispersible. . 5. The aqueous resin according to claim 2, 3 or 4, wherein the compound having the above-mentioned reactive group and also having water solubility is a compound having a reactive group such as a hydroxyl group or a carboxyl group. Composition.