JPS5952186B2 - Water-soluble paint composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water-soluble coating composition mainly containing an imide and an esterified derivative of a copolymer of α-olefin and maleic anhydride, to which a reactive modifier is added. .

Most of the paints currently in common use contain an organic solvent as a component, no matter what kind of resin they are made of.

Moreover, the amount used is relatively large, and the organic solvent used is dissipated into the atmosphere during the drying process, resulting in deterioration of the working environment and a source of oxidants. Therefore, a solution to this problem is strongly desired. One method is to use water-soluble paints.

Such water-soluble paints need to be pollution-free and resource-saving paints that do not use photochemically reactive organic solvents and contain low amounts of organic solvents. Electrodeposition paints, which are a typical type of water-soluble paint, require an electrodeposition device to apply the paint, which requires a large amount of equipment costs, and the equipment must be operated under close supervision. Otherwise, the incidence of defective products will increase.
Furthermore, since the paint is applied to the object based on electrophoresis, the object to be coated is limited to electrically conductive metals and cannot be overcoated. There are other water-soluble paints besides electrodeposition paints,
Whether it is made mainly of alkyd resin or acrylic resin, it is necessary to dry it at a relatively high temperature, and if it is dried naturally, there will be disadvantages such as the coating being too soft. Therefore, there is a problem in that the objects to be coated are limited to those that can withstand high temperatures. In addition, defects may appear, for example, in terms of gloss or fading of pigments. As mentioned above, the current situation is that the various physical properties of coating films, including water resistance, are generally inferior to those of conventional organic solvent systems. Also, although it cannot be called a water-soluble paint, there is also an emulsion paint that uses water as a medium, but this paint has the problem of film-forming properties, so it is mainly applied only to interior and exterior wall paints. do not have.

In other words, in order for resin dispersed as extremely fine particles in water to form a continuous film, a temperature above the so-called glass transition point is required. It will be under a temperature of
In the end, in extreme cases, the film will be so flexible that it will feel sticky, so at room temperature it will not be possible to create a film that is transparent but has sufficient hardness; It is only applied to wall paints that can compensate for hardness. The inventors of the present invention took the above-mentioned circumstances into account, and as a result of repeated studies, they found that it can be diluted infinitely with water without using almost any organic solvent, and can be dried either naturally or forcedly. As a paint that can be applied to an extremely wide range of applications such as metal, wood, plastics, cement, etc.
It has been found that a composition containing an imide and an esterified derivative of a copolymer of α-olefin and maleic anhydride as a main ingredient and an appropriate reactive modifier added thereto satisfies the above requirements.

That is, a coating composition with good water resistance, alkali resistance, adhesion, strength, gloss, etc. was discovered. In the present invention, the purpose is achieved by adding a reactive modifier to a water-soluble imidized derivative of the copolymer, diluting it with a diluent, and applying it to the object to be coated as a coating composition. Achieve it.

In the present invention, α-olefin refers to a linear or branched chain having 2 to 8 carbon atoms, preferably 2 to 6 carbon atoms.
For example, ethylene, propylene, n-butene, isobutylene, n-benzene, isoprene, 2-methyl-1-butene, n-hexene, 2-methyl-1-benzene, 3-
Methyl-1-penane, 4-methyl-1-benzene, 2
-ethyl-1-butene, etc.

Among these, isobutylene is particularly preferred. In addition, isobutylene here refers to return B- containing isobutylene.
It also means B. Therefore, the copolymer used in the present invention is represented by the following formula.

R,,R2 represents H or an alkyl group The copolymer is polymerized using a suitable solvent in the presence of a conventional radical initiator, and from the results of compositional analysis, it is found that in the case of a binary copolymer, that is, [ I]-[], the molar ratio is approximately 1:1
I admit that it is.

On the other hand, the imide and esterified derivative of the copolymer is an esterified product of an alcohol and a monoepoxy compound, and is represented as follows. P. ,, R,,R,:H or an alkyl group (R is an alkyl group, other aliphatic residue, aromatic residue or cyclic residue) R,:H or an alkyl group, another aliphatic residue, The aromatic residues or cyclic residues A, b, c, and d are the composition ratios of the constituent units of the copolymer derivative expressed in mol%.

a+b+c+d=100 aξb+c+d bow 50 5≦bku40 10kudku40 c can be freely changed within the range subject to the above.

The type of imidization is not particularly limited, and maleic acid imide and N
Refers to monosubstituted maleic acid imide type derivatives. The type of esterification is partial diesterification with alcohols and monoepoxy compounds. The derivative can be obtained as follows.

That is, an α-olefin-maleic anhydride copolymer (hereinafter abbreviated as MA) is mixed with a suitable nitrogen compound that provides the desired maleic acid and N-substituted maleic acid imide (hereinafter abbreviated as M) structure. can be obtained by heating these nitrogen compounds at 150° C. or higher in a vapor atmosphere or in a medium. Such nitrogen compounds include ammonia,
Examples include primary aliphatic amines, aromatic amines, hydroxyalkylamines, and the like. The imidized derivative obtained in this way is first monoesterified with alcohol by a normal esterification method, and then a predetermined amount of a monoepoxy compound is added to easily achieve the predetermined partial diesterization without removing condensed water. A derivative is obtained. Since the imidized and esterified derivatives of the copolymer are soluble in aqueous alkaline solutions, they can be used by dissolving them in an aqueous solution containing an appropriate amount of an alkaline substance such as caustic alkali, alkali carbonate, ammonia, or organic amines. is preferred.

If the value of b is small (1), the acid value will be small, and although it cannot be completely water-solubilized with an alkaline substance, a small amount of organic solvent (for example, non-photochemically reactive butanol, butyl cellosolve, etc.) may be used in combination. This will give you a cloudy dispersion, so this is fine. When b is less than 5, the system is unstable and may separate, and the dried coating film may become uneven, which is disadvantageous. If b is 40 or more, the water resistance of the air-dried coating film may be reduced or the coating film may become hard. The purpose of imidization is to improve water resistance and alkali resistance, and to improve the softening of the coating film through esterification.

In other words, it maintains the coating film at an appropriate level of hardness and provides water resistance and alkali resistance. Another advantage is that the paint film naturally dries quickly and the painted surface becomes non-sticky. Therefore, when d is in the range of 10 or less, it becomes difficult to obtain alkali resistance and water resistance unless the degree of esterification is increased, resulting in the disadvantage that the coating film becomes soft. Moreover, if it is 40 or more, the coating film will be too hard and the viscosity of the alkaline aqueous solution will become high, resulting in the inconvenience that the solid content of the coating must be lowered. The reactive modifier referred to in the present invention refers to carboxyl groups, 0H groups,
It acts on functional groups such as imide groups to harden the resin, and includes alcohols, compounds containing epoxy groups, compounds containing amino groups, melamine resins, hexamine, aldehyde compounds such as paraformaldehyde, metal complexes,
There are metal compounds, etc.

Hereinafter, these reactive modifiers will be explained in detail. (1) Alcohols include aliphatic or aromatic monovalent to tetravalent alcohols that are soluble or partially soluble in water, and polyvalent alcohols such as polyvinyl alcohol, polysaccharides, dextrin, and starch. Alcohol can be given.

Also included are ether type alcohols such as polyethylene glycol and polypropylene glycol. These alcohols may be used alone or in combination of two or more. (2) Compounds containing epoxy groups include diglycidyl ether, bisphenol A1 glycerin, diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, and polypropylene glycol diglycidyl ether. Examples thereof include glycidyl ether type compounds such as, glycidyl ester type compounds such as diglycidyl phthalate and diglycidyl maleate, and alicyclic oxides such as vinyl cyclohexene dioxide.

These epoxy group-containing compounds may be used alone or as a mixture of two or more. (3) Compounds containing amino groups include aliphatic or aromatic primary to tertiary amines that are as soluble in water as possible and have a high boiling point; examples of polyvalent amines include ethylenediamine, propylenediamine, and triethylene. Examples include aliphatic or aromatic amines such as tetramine, tetraethylenepentamine supermine, m-tolylenediamine, and polyethyleneimine.

In addition to these amines, alicyclic amines can also be used. These amine group-containing compounds may be used alone or as a mixture of two or more. (4) Area melamine resin is a condensation product of urea and/or melamine with formaldehyde, and/or an etherification product of the above condensate with alcohol, in which the type of urea, type of melamine, or type of alcohol is changed. It is a resin that is as easily soluble in water as possible.

(5) Aldehyde compounds are compounds such as formaldehyde, paraformaldehyde, hexamine, etc. that are used in an aqueous system and react with imide groups during drying to form methylene crosslinks. (6) Metal complexes include complex salts of silicon, calcium, or first transition metals such as titanium, manganese, iron, cobalt, and nickel with anionic ligands such as acetate, cyano, nitro, hydrooxo, or glycinate; Ako, Anmin,
Examples include complex salts with neutral molecules such as ethylenediamine and pyridine, and complex salts with cationic ligands such as hydrazinium and 2-aminoethylammonium.

These metal complex salts containing two or more types of ligands in the complex molecule may also be used. Further, these metal complexes may be used alone or as a mixture of two or more. (
7) Metal compounds include calcium, magnesium,
Zinc, barium, cadmium, lead, copper, aluminum,
These include oxides or hydroxides of iron, and these oxides or hydroxides are constituents of bentonite, clay, and talc, as well as aluminum sulfate commonly used in the paper industry. A complex of calcium hydroxide and calcium hydroxide, such as "Satin Shiro", is also cited as similar to these.Among these oxides or hydroxides, oxides or hydroxides of zinc, calcium, and aluminum are particularly preferred.

These metal oxides and hydroxides may be used alone or in combination of two or more.

(8) Other reactive modifiers include compounds containing hydroxyl groups and amino groups in the molecule, such as ethanolamine;
Compounds having two or more different functional groups within the same molecule, such as compounds containing a glycidyl group and an unsaturated group within the molecule, such as glycidyl methacrylate, may also be used.

Other examples of such compounds include 2-hydroxyethyl methacrylate, N-methylol acrylamide, dimethylaminoethyl methacrylate, and epichlorohydrin ricinoleate. In addition, hydroxyl group,
Polymers or copolymers containing one or more functional groups such as amino groups and epoxy groups in the molecule can also be used as the reactive modifier of the present invention. Such polymers or copolymers include methyl methacrylate-2-hydroxyethyl methacrylate-acrylic acid copolymer;
Styrene-N-methylol. Examples include acrylamide-2-hydroxyethyl methacrylate-ethyl acrylate copolymer, glycidyl methacrylate-ethel acrylate-acrylic acid copolymer, and the like. (1)～(
The reactive modifiers listed in 8) may be used alone or in combination of two or more.

These reactive modifiers do not necessarily have to be soluble in water to be used. However, it is necessary to dissolve the imidized and esterified derivatives of copolymers of maleic anhydride and olefin. Therefore, the coating composition of the present invention may be an opaque aqueous dispersion solution in the case of a coating liquid containing only the main copolymer and a curing agent without adding additives such as pigments. However, when formed into a coating, it becomes a transparent film. Among (1) to (8), those particularly suitable as the coating composition of the present invention are alcohols (1), (2)
) is a compound containing an epoxy group, and (4) is an area melamine resin.

The amount of these reactive modifiers to be used with respect to the main ingredient is 5 to 10
It is 0% by weight. Of these, the particularly appropriate amount to use is 10 to 6
It is 0% by weight. This usage amount is (1), (2), (4)
Both are common. Aged 7P as a reactive modifier of the present invention
−(J, (2), cause 3 other than (4)), (5), (6),
Since (7) and (8) also have distinctive effects in addition to the original hardening effect, they are often used in combination with (1), (2), (4), etc. For example, the compound (3) containing an amino group exhibits the effect of promoting the solubility of the main ingredient in water, and the metal complex salt (6) and the metal compound (7) exhibit the effect of promoting the solubility of the base ingredient in water, as described above, and the metal complex salt (6) and the metal compound (7) exhibit the effect of promoting the solubility of the main ingredient in water. This is because it exhibits a catalytic action that promotes the curing of compounds such as ) and (4). In addition, due to its polyfunctionality, the other reactive modifiers (8) can improve the physical and chemical properties of the coating film even in small amounts when used in combination with other reactive modifiers. It shows the function of These (3χ(6),
The amount of reactive modifier used in (7) is from 0.1 to 0.1 due to the above-mentioned properties.
It is 80% by weight. Especially when used in combination, 0.
1 to 20% by weight is suitable. When these reactive modifiers are used, they are used as they are or dissolved in water.

If it does not dissolve in water, it can be dissolved in water using a suitable medium that dissolves in water, or it can be used as a stable aqueous dispersion by using a surfactant or the like. The aqueous solution of the base agent composed of the imidized and esterified derivatives of the copolymer and the reactive modifier prepared as described above are mixed in advance to accelerate curing and used as a one-component product. However, it is also used as a two-part or multi-part form that is mixed immediately before use. When actually painting the above paint composition, it may be necessary to add color or increase the thickness of the paint film depending on the intended use, but in that case, it may be necessary to add pigments or dyes. It is possible to add color, or add an extender or filler to increase the film thickness.

In addition, if it is necessary to change the properties of the coating film such as gloss, flexibility, etc., it is possible to adjust it by adding substances such as matting agents, emulsions, latexes, or plasticizers. It is also possible to add surfactants, diluents, moisturizers, sensitizers, etc. in order to improve the overall efficiency of coating operations such as coating properties, coating properties, polishing properties, and drying properties. Among these, the diluent is indispensable for adjusting the viscosity during coating work, so it will be explained in detail. Clean water with a pH of 6 to 9 is usually sufficient as a diluent, but if necessary, diluents containing alcohols, amines, etc. can also be used. The amount of alcohols, amines, etc. to be added may be as small as 20% by weight or less based on water. Diluents are also used as cleaning agents for equipment, utensils, etc., but in this case, almost exclusively water is used. Various additives other than the diluent are mainly added to the aqueous solution of the imidized and esterified derivatives of the copolymer, but they may also be added to the reactive modifier. Therefore, the same additive and reactive modifier added to both may be used. The concentration of the water-soluble coating composition as described above, which is composed of the base reactive modifier and/or various additives, is 20 to 60% by weight. However, since the viscosity may be adjusted with a diluent during coating, it is sometimes used at a concentration lower than the above. The characteristics of the coating composition of the present invention produced as described above are as follows. (1) Since it is water-soluble, the working environment is significantly improved and environmental pollution can be prevented. In addition, cleaning can be performed easily with water. Furthermore, since there is no need to dissipate expensive organic solvents, costs can be reduced. (2) Since the viscosity can be easily adjusted, various painting methods such as spray gun, brush, roll coater, flow coater, and date coating can be used, making painting work easy.
Therefore, there is no need to prepare special coating tools for the water-soluble coating composition of the present invention. (3) It can be dried quickly even if it is applied and left at normal temperature and humidity (10-40℃, RH4O-80%), and it can be dried quickly in hot air drying ovens, infrared drying ovens,
It can also be dried by forced drying using a gas infrared drying oven. The drying time is from several tens of minutes to several hours for natural drying, and from several minutes to several tens of minutes for forced drying, which is almost the same as conventional organic solvent paints. can do. It is possible to further streamline the process by taking advantage of the above-mentioned features regarding painting and this feature regarding drying. (4) The water-soluble coating composition of the present invention has excellent adhesion so that it can be used as an adhesive, so it can be applied to a wide range of objects such as wood, metals, plastics, mortar, etc. I can do it. Furthermore, since there are a wide variety of reactive modifiers, it is advantageous in obtaining adhesion properties suitable for various materials. (5)
It has excellent physical properties such as hardness, gloss, and flexibility, as well as excellent chemical properties such as acid resistance, light resistance, and weather resistance. Furthermore, by adjusting the imidization rate and esterification degree, the hardness of the coating film with good water resistance can be selected. (6) It has almost no solubility in organic solvents, and especially if forced drying is performed, the alkali resistance, which is a drawback of esterified products, is greatly improved. (7) Since the coating compositions obtained according to the present invention can be coated in layers, a consistent coating finish can be achieved from undercoating to intermediate coating to topcoating. It is also possible to overcoat with conventional coating compositions such as lacquer, melamine alkyd, urethane, acrylic, amino alkyd, oil-based, epoxy, and the like. Next, the present invention will be specifically explained using examples.

Needless to say, the present invention is not limited to these examples. Reference example Isobutylene-maleic anhydride copolymer (mole ratio 1:1
) (Invan-04 manufactured by Kuraray Co., Ltd.) was reacted for 20 minutes at 30° C. in an ammonia gas stream (forced to flow with N2 gas, ammonia concentration 35%).

(This product is called an ammonia-modified product.) Since this reaction is exothermic and easily proceeds, it is necessary to carry out the reaction while cooling. The degree of ammonia modification was 50m01% based on the weight increase of the copolymer. (When one carboxyl group in Inban is modified to an amide or ammonium salt, the degree of modification is 50m01%) This ammonia-modified Inban 20
09 was heated to 180° C. under a N2 gas stream to perform a dehydration reaction. By changing the reaction time while checking the amount of dehydration, the imidization ratios shown in Table 1 were obtained. Example 1 The isobutylene-maleic anhydride imidized derivative 2009 of /F6l~Taki5 obtained in Reference Example 1 was mixed with n-butanol 550
9 to 16 three-bottle flasks, equipped with a stirrer, thermometer, and reflux condenser, and heated at 118°C in an oil bath for 6 hours.
The degree of esterification is shown in Table 2 (the degree of esterification is expressed as the mol% of ester groups relative to the carboxyl groups of the original maleic anhydride copolymer).

) butyl monoester was obtained. The butyl esterification reaction reaches equilibrium in 5 to 6 hours, and the reaction will not proceed unless the condensed water is removed from the reaction system. That is, it is completely monoesterified. Next, to the butanol solution of this monoesterified product, monoglycidyl monoglycidyl ester of versatility (Cardilla E manufactured by Shell Co., Ltd., abbreviated as CDE) was added in varying amounts and reacted at 118°C for 6 hours to obtain a diesterified product. The degree of esterification is shown in Table 2. show. A water-soluble paint was prepared in the following manner using the butanol solution of the imidized and esterified derivative obtained as described above.

That is, after removing excess unreacted butanol from the butanol solution under reduced pressure so that a predetermined amount of butanol remains, aqueous ammonia (28%) was added in an amount equivalent to the remaining carboxyl groups (with a degree of neutralization of 1.0). ) and then the solid content is 3
Water was added to give a concentration of 8%, and the mixture was stirred at 80°C for 2 hours to obtain an aqueous solution. Table 3 shows the physical properties of this aqueous solution. This aqueous solution 1
00g was diluted twice with water, and glycerin type diglycidyl ether (NER-010 manufactured by Nagase Sangyo) was diluted with 20Cfb/
Add the solid content, add a few drops of an antifoaming agent mainly composed of silicone resin, mix well, and use a spray gun (caliber 1.31, air pressure 4.
It was applied to glass plates and rosewood veneers at ~°.

For items that cannot be applied by spray, apply with an applicator bar, leave for 15 minutes, defoaming, and then dry in a hot air dryer at 50℃ for 2 hours.
．． Dry. The physical properties of this low-temperature-dried coating were excellent. Measurement method 1 Dryness: The time (minutes) at which the coating solution stops sticking to the fingers at a hot air drying speed of 50°C is the drying time to the touch, and the time (minutes) until no finger squeezing remains after pressing the coated surface with the finger is the shiatsu drying. That's what it means.

2. Transparency: Light transmittance of 420 mμ (an uncoated glass plate is used as a control) 3. Surface hardness: Pencil hardness that does not scratch when the lead is held flat and applied to the painted surface at a 45° angle 4. Water resistance: 20℃ water drip test Drop water on the painted surface and see how long it takes for a change to appear.

5 Alkali resistance: 20℃, 5% NaOH water drip test 6
Solvent resistance: Place a drop of Ratsuker Thinner on the paint film and observe the time until there is any change.

7 Cold check - 20℃ x 2hr → 50℃ x 2hr
Let r be one cycle, and check whether there is any abnormality in the coating film every cycle.

8 Adhesion: Draw 11 lines on the coating film at 1n intervals with a sharp knife, then draw 11 lines perpendicular to the lines, and judge by how many of the lines are peeled off (100 indicates perfect adhesion) Example 2 Aqueous solution (38%) of samples 3 and 8 obtained in Example 1
1009, hexamethylenetetramine 8%/solid content and melamine resin (Sumitex Resin 613 manufactured by Sumitomo Chemical)
) with 20% solid content/solid content added (1
Baking at 50°C for 30 minutes) is shown in Table 5.

Claims (1)

[Claims] 1 Consists of a copolymer of α-olefin and maleic anhydride, and has a general formula ▲ Numerical formula, chemical formula, table, etc. ▼ R_1, R_2: H or alkyl group R_3: Alkyl group, other fat Group residue, aromatic residue, or cyclic residue R_4: ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (R is an alkyl group, other aliphatic residue, aromatic group residue or cyclic residue) R_5: H or an alkyl group or other aliphatic residue, aromatic residue or cyclic residue a, b, c, d of the copolymer derivative expressed in mol% This is the composition ratio of the constituent units. a+b+c+d=100 a≒b+c+d≒50 5≦b<40 10<d<40 c can be freely changed within the ranges dependent on the above. A water-soluble coating composition mainly consisting of an imide and an esterified derivative represented by the following formula, to which a reactive modifier is added.