JPH02185578A - Cellulose derivative-containing aqueous coating resin composition and method for producing the same - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to an aqueous coating resin composition and a method thereof, and more particularly to an aqueous coating resin composition containing a cellulose derivative and a method for producing the same. Regarding.

[Conventional technology]

Lacquer-type paints containing cellulose derivatives.

Used for woodworking because it has excellent drying properties, solvent resistance, gloss, and mechanical strength, and is easy to handle with paint.

It is used as a base material for paints and metals.

However, since conventional lacquer-type paints containing cellulose derivatives are made by dissolving a film-forming resin in an organic solvent such as toluene, ethyl acetate, or methyl ethyl ketone, the solvent is likely to be dispersed into the work atmosphere of the cabinet making work. As a result, the working environment not only deteriorates and human safety is impaired, such as solvent poisoning of workers, but also it pollutes the atmosphere, and because organic solvents are flammable, there is a risk of fire and explosion. was always present.

[Problem to be solved by the invention]

In order to avoid these problems, particularly air pollution, deterioration of the working environment, and the risk of fire and explosion, attempts have been made to make lacquer-type paints containing cellulose derivatives water-based.

For example, JP-A No. 51-28188 discloses a method of dispersing a polymer containing a cellulose derivative in water using a large amount of 1%' special emulsifier.

However, the aqueous dispersion obtained by the above method has poor dispersion stability, tends to aggregate and separate during blending or storage, and furthermore, the resulting coating film also tends to separate.

Compared to coating films obtained from lacquer-type coatings containing cellulose derivatives, these had problems such as significantly inferior gloss, 1 liter durability, and mechanical strength.

The present invention seeks to solve y! The title is: 1) Water-based coatings containing cellulose derivatives with excellent dispersion stability that can form coatings with low tackiness, oil resistance, and excellent solvent resistance, abrasion resistance, and mechanical strength. An object of the present invention is to provide a resin composition and a method for producing the same.

[+ step to solve the problem] The present invention aims to solve the above problems.

(]] Hal hydroxyl group-containing cellulose derivative 9000-9
9.95% by weight and (bl acrylic anhydride and/or methacrylic anhydride 0.95% by weight)
and 5 to 95 parts by weight of a vinyl group-containing reactant obtained by reacting 0.05 to 10.00 x 1%.

(2) An aqueous coating resin composition comprising a copolymer with 95 to 5 parts by weight of a polymerizable vinyl monomer containing at least 2% by weight of a carboxyl group-containing vinyl monomer dispersed in an aqueous medium (hereinafter referred to as the present invention). (referred to as a coating composition).

The coating composition of the present invention can be produced, for example, by the following method.

That is, ti) (a + hydroxyl group-containing cellulose derivative 90
．． 00 to 99.95 parts by weight (bl acrylic anhydride and/or methacrylic anhydride 0.00 to 99.95 parts by weight)
Polymerizable vinyl containing 5 to 95 x Ji parts of a vinyl group-containing reactant obtained by reacting 05 to 10.00 wt. A first step of producing a carboxyl group-containing modified polymer by copolymerizing 95 to 5 parts by weight of monomers in the presence of a polymerization initiator; The second step consists of neutralizing at least a portion with a basic compound, then finely dispersing the neutralized product in water, and using the basic compound in an amount such that the dispersion has a voice of 5 or more. This is the manufacturing method.

The hydroxyl group-containing cellulose derivative used in the present invention uses cellulose as a raw material, and the resulting aqueous coating resin composition is applied to a substrate and dried, and the surface of the coating film obtained does not exhibit tackiness and has a pleasant texture. Those that can form a coating film with excellent abrasive properties are preferred.

As such a hydroxyl group-containing cellulose derivative.

One example is one commonly used for paints.

Examples include ester-modified hydroxyl group-containing cellulose derivatives and ether-modified hydroxyl group-containing cellulose derivatives.

Examples of ester-modified hydroxyl group-containing cellulose derivatives include cellulose nitrocellulose, cellulose acetate butyrate, cellulose acetate propionate), cellulose acetate phthalate, cellulose acetate, and cellulose propionate.

Examples include cellulose butyrate, cellulose phosphate, cellulose sulfate, and the like.

Examples of the ether-modified hydroxyl group-containing cellulose visiting conductor include methyl cellulose, ethyl cellulose, butyl cellulose, and benzyl cellulose.

Carboxymethyl cellulose, carboxyethyl cellulose, aminoethyl cellulose, oxyethyl cellulose, hydroxyethyl cellulose.

Examples include hydroxynorobilcellulose, hydroxypropylmethylcellulose, and the like.

Among these hydroxyl group-containing cellulose derivatives, cellulose acetate butyrate (hereinafter referred to as CAD) obtained by further butyl esterification of partially acetylated cellulose is
That's what it means. ) is particularly preferred.

The number average molecular weight of the hydroxyl group-containing cellulose derivative used in the present invention is preferably in the range of 3,000 to 300,000, particularly preferably in the range of 5,000 to 150,000.

The content of hydroxyl groups in the hydroxyl group-containing cellulose crocodile conductor used in the present invention is preferably 0.4% or more9). When the content of hydroxyl groups is less than 0.4%.

As the number of (meth)acryloyl groups that can be introduced into the hydroxyl group-containing cellulose derivative decreases, the grafting rate decreases,
This is not preferred because the carboxyl group-containing modified polymer tends to be difficult to self-emulsify.

Examples of commercially available hydroxyl group-containing cellulose enzyme conductors used in the present invention include ``CAB J series'', ``CAP J series'', and ``C
Examples include the AJ series.

The vinyl group-containing reactant according to the present invention is obtained by mixing the above-mentioned hydroxyl group-containing cellulose derivative with acrylic anhydride and/or methacrylic anhydride in an inert organic solvent at 50 to 120°C.
It can be produced by reacting for 0 minutes to 8 hours. Although this reaction proceeds even without a catalyst, the reaction is further promoted in the presence of an esterification catalyst. As described above, it is difficult to introduce a (meth)acryloyl group into a hydroxyl group-containing cellulose derivative without a catalyst using a conventional method.

This became possible for the first time using highly reactive acrylic anhydride and methacrylic anhydride. The reaction rate of this nistylation reaction is determined by the acid value or the Fourier transform infrared spectrophotometer (FT
-IR), etc.

Examples of the esterification catalyst include amines, alkali metal hydroxides, mineral acids, and the like. Preferred half-esterification catalysts include trialkylamines such as trimethylamine, triethylamine, and tripropylamine; N-alkylmorpholine; triethylenediamine, N,N'-dimethylpyrazine, hexamethylenetetramine, pyridine,
Examples include pyrazine, quinoline, benzyldimethylamine, α-methylbenzyldimethylamine, N-furkylimidacilline, triphenylphosphine, tricyclohexylhonuphine, and the like.

The ratio of the hydroxyl group-containing cellulose derivative to acrylic anhydride and/or methacrylic anhydride is 90:10 by weight.
The range of 99.95:0.05 is preferable.

A range of 95:5 to 99.9:0.1 is particularly preferred.

If the proportion of acrylic anhydride and/or methacrylic anhydride used is less than 0.05 weight, it is not preferred because the dispersion stability of the carboxyl group-containing modified polymer in an aqueous medium tends to be poor.

The usage ratio of acrylic anhydride or methacrylic anhydride is 10
If it is more than % by weight, the carboxyl group-containing modified polymer tends to have a high molecular weight during polymerization.

This is not desirable because it tends to form a group.

Acetone is used as an inert organic solvent when producing the vinyl group-containing reactant used in the present invention.

Methyl ethyl ketone, methyl isobutyl ketone.

Ketone solvents such as F-/l/globyl ketone and ethyl butyl ketone are preferred.

The polymerizable vinyl monomer used in the copolymerization reaction with the vinyl group-containing reactant is a polymerizable vinyl monomer containing at least 2% by weight of a carboxyl-containing vinyl monomer.

The amount of carboxyl group-containing vinyl monomer used is 2% by weight.
In case of less.

The dispersion stability of the resin in an aqueous medium, the adhesion and solvent resistance of the painted film to metals, and when used for the interior of cans, the flavor suitability, etc. all tend to deteriorate, so they are not preferred.

As a carboxyl group-containing vinyl monomer.

Examples include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, and the like.

Examples of polymerizable vinyl monomers other than carboxyl group-containing vinyl monomers include styrene.

Vinyltoluene, 2-methylnutile7. Styrenic heptamers such as t-butylnutylene and chlorstyrene; methyl acrylate, ethyl acrylate, impropyl acrylate, and n-butyl acrylate.

Isobutyl acrylate, n-amyl acrylate.

Isoamyl acrylate, n-hexyl acrylate.

Acrylic acid esters such as 2-ethylhexyl acrylate, n-octyl acrylate, decyl acrylate, dodecyl acrylate; methyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-amyl methacrylate, Methacrylic acid esters such as n-hexyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, gasyl methacrylate, dodecyl methacrylate; hydroxyethyl acrylate, hydroxyglobil acrylate.

Hydroxyl group-containing monomers such as hydroxyethyl methacrylate and hydroxyglobyl methacrylate; Monoacrylic acid or monomethacrylic acid ester monomers of alkylene glycols such as polyethylene glycol and polyethylene glycol or their monoalkyl ethers; glycidyl Glycidyl group-containing polymers such as acrylate and glycidyl methacrylate; N-methylol (
Examples include N-substituted (meth)acrylic monomers such as meth)acrylamide and N-butoxymethyl(meth)acrylamide.

The carboxyl group-containing modified polymer of the present invention is produced by solution polymerizing the vinyl group-containing reactant and the polymerizable vinyl monomer.

The ratio of the vinyl group-containing reactant to the polymerizable vinyl monomer is preferably in the range of 5:95 to 95:5 by weight. If the proportion of the vinyl group-containing reactant used is less than 5% by weight, it is not preferable because the various properties of the hydroxyl group-containing cellulose derivative may not be utilized. If the proportion of the vinyl group-containing reactant used is more than 95% by weight, the carboxyl group-containing modified polymer tends to be difficult to self-emulsify, which is not preferred.

In particular, those with a low proportion of polymerizable vinyl monomer are
Since the proportion of cellulose derivatives in the carboxyl group-containing modified polymer is high, the characteristics of cellulose derivatives can be brought out by adding it to other water-based acrylic resins, polyester resins, and urethane resins. In this case, there may be used a method in which the coating composition of the present invention is added to the aqueous resin, or a method in which the coating composition of the present invention is mixed with the aqueous resin at the stage of forming a carboxyl group-containing modified polymer and then dispersed in water.

Examples of the polymerization initiator used in the copolymerization reaction between the vinyl group-containing reactant and the polymerizable vinyl monomer include azobinisobutyronitrile, penzoylno, monooxide, t-
Butirno! -Usual radical polymerization initiators such as -oxy-2-ethylhexanate can be mentioned.

Examples of the organic solvent used in the copolymerization reaction include 1.

Alcohols such as methanol, ethanol, noro/9-ol, butatol; ether alcohols such as methyl cellosolve, ethyl cellosolve, flovir cellosolve, butyl cellosolve, methyl calpitol, ethyl calpitol; ketones such as methyl ethyl ketone, diisobutyl ketone, and toluene Examples include aromatic hydrocarbons such as

The coating composition of the present invention is prepared by adding a basic compound to the carboxyl group-containing modified polymer obtained by the polymerization reaction in an amount such that the dispersion has a voice of 5 or more.

It is obtained by dispersing the modified polymer in an aqueous medium.

The basic compound used here is preferably ammonia or a volatile amine, and inorganic bases are not preferred because they tend to remain in the coating and impair water resistance.

The above amine is, for example, trimethylamine.

Alkylamines such as triethylamine and butylamine; alcohol amines such as dimethylamine ethanol, jetanolamine and aminomethylgropanol; morpholine and the like can be used. Polyvalent amines such as ethylenediamine and diethylenetriamine can also be used.

In the present invention, the aqueous medium means water alone or in a mixture with a hydrophilic organic solvent, in which at least 10% by weight is water. As a hydrophilic organic solvent.

For example, methanol, ethanol, n-gulononol, isoprotyanol, n-butanol, 11@e-
Alkyl alcohols such as butanol, tert-butanol, isobutanol; methyl cellosolve.

Glycol ethers such as ethyl cellosolve, norovir cellosolve, butyl cellosolve, hexyl cellosolve, methyl calpitol, ethyl carpitol; glycol ether esters such as methyl cellosolve acetate, ethyl cellosolve acetate; others, dioxane, dimethylformamide, diaheptone alcohol , tetrahydrofuran, etc. can be used.

The coating composition of the present invention has very good dispersion stability, and when it is necessary to reduce the amount of organic solvent contained, it is possible to use a low boiling point solvent such as acetone or methyl ethyl ketone, or a solvent such as butanol or butyl cellosolve. If a solvent that is azeotropic with water is used as a reaction solvent or dispersion aid, it can be dispersed in an aqueous medium and then distilled at normal pressure or reduced pressure.
A nucleated composition with a low organic solvent content can be stably and easily obtained.

A solvent, a surfactant, an antifoaming agent, a matting agent for improving paintability and physical properties of the coating film as necessary in the coating composition of the present invention,
Anti-settling agent, anti-sagging agent, anti-corrosion agent.

It is also possible to add thickeners, leveling agents, ultraviolet absorbers, antioxidants, etc. It is also possible to add an amine resin or a phenol resin to the coating composition of the present invention as a curing agent. Furthermore, various pigments can be added as necessary.

Painting methods include conventionally known paulownia coat, roll coating,
Electrodeposition coating and spray coating at the anode.

Flow coating is preferred.

The coating composition of the present invention is usually used as a lacquer type paint, but it can also be used as a baking paint.
In that case, baking conditions of 2 seconds to 30 minutes at 100 to 250°C are preferred.

The characteristics of the coating composition of the present invention are as follows. That is, (1) the carboxyl group-containing modified polymer of the present invention uses a cellulose derivative with different compatibility and a xyl group-containing vinyl group-containing polymer, but these are chemically bonded together. Because it is a polyester, it does not cause phase separation, and because it has a carboxyl group, it has self-emulsifying properties in an aqueous medium, and therefore has very good dispersion stability.

(2) Because it is possible to produce an aqueous coating resin composition due to the ratio of cellulose derivatives, by adding this composition to other aqueous coating resin compositions, it has the extreme characteristics of cellulose derivatives. A wide variety of aqueous coating resin compositions can be obtained.

Due to these characteristics, the coating composition of the present invention is useful for coating materials such as plastics, wood, and metals. The most preferred use of the coating composition of the invention is as a lacquer-type coating on plastics.

〔Example〕

The present invention will be explained below with reference to examples. In addition.

In the examples, "part" and "%" are 1 part by weight and 1 part by weight, respectively.
”.

Example 1 [Production of vinyl group-containing reactant] (1) [CAB-553J 12
5 parts (2) 0.5 parts of methacrylic anhydride (3) 250 parts of methyl ethyl ketone ("CAB-553J" in (1) above is cellulose acetate butyrate manufactured by E. Toman Co., Ltd. in the United States,
It has 4.3% hydroxyl groups in the molecule. ) After charging the above (1) and (3) into a 40 flask purged with nitrogen gas and dissolving them completely, add the above (2), heat the contents to 80°C while stirring, and stir at the same temperature for 5 hours. By doing so, a vinyl group-containing reactant was obtained.

[Preparation of water-based resin composition]

(4) Reaction mixture containing 200 parts of the vinyl group-containing reactant 5) 100 parts of methyl ethyl keto 7 G) n
-Butanol 100 parts Methacrylic acid 0 parts 8) Methyl methacrylate 160 parts 9) Butyl acrylate
70 parts (10r perbutyl 0)
6 parts ("Perbutyl 0" in α0 above is t-butyl peroxy-2-ethylhexanate (radical polymerization initiator) manufactured by NOF Corporation.) (1st step) (4) above, ( 5), (6j, (7), (
8), (9) & U (1t1k After uniformly mixing, 200 parts of the mixed solution was replaced with nitrogen gas, charged into a 'fL40 Flanuco, and heated to 80°C.

While maintaining the temperature, the remaining mixture was gradually added dropwise over 4 hours, and the mixture was further stirred at the same temperature for 4 hours to obtain 4fc of the caroxyl group-containing modified polymer.

(Second step) After adding 7 parts of ammonia water (containing 28%) and 60 parts of butyl cellosolve to the reaction solution containing the modified polymer obtained in the first step and mixing uniformly, 500 parts of ion-exchanged water was added for 30 minutes. I applied it and dripped it.

A milky blue-white aqueous coating resin composition having a solid content of 24.9% and a pH of 7.5 was obtained.

The viscosity of this composition did not change even after this composition f: was left at room temperature for one week. Furthermore, when the organic solvent in this composition was distilled off under reduced pressure to remove methyl ethyl ketone, n-butanol, and some butyl cellosolve, the solid content was 40.
．． A good aqueous dispersion of 1% was obtained.

Example 2 An aqueous coating resin composition was prepared in the same manner as in Example 1, except that the following composition was used.

(4) Reaction mixture containing 200 parts of the vinyl group-containing reactant used in Example 1 (5)' Methyl ethyl ketone 2
0 parts (6)' n-butanol 40
parts (10 parts of methacrylic acid)
8)' Methyl methacrylate 5 parts (9)
'Butyl acrylate 5 parts (10)'
2 parts of r.zo-butyl OJ (first step) In the same manner as in Example 1, a carboxylic group-containing modified 1 compound was obtained.

(Second step) After adding 7 parts of ammonia water (containing 28%) and 30 parts of butyl cellosolve to the reaction solution containing the modified polymer obtained in the first step and mixing uniformly, 250 parts of ion-exchanged water was added for 30 minutes. When added dropwise, the solid content was 15.0% pl (7.6
A milky blue-white aqueous coating resin composition was obtained, the viscosity of which did not change even after the composition was left at room temperature for one week. or.

When the organic solvent in this composition was distilled off under reduced pressure to remove methyl ethyl ketone, butanol, and a portion of butyl cellosolve, a good aqueous dispersion with a solid content of 42.1% was obtained.

Comparative Example 1 In Example 2, "CA" which had not been treated with methacrylic anhydride was substituted for the reaction mixture containing the vinyl group-containing reactant.
The reaction was carried out in the same manner as in Example 2, except that a solution containing B-s 53 J was used.

It was not possible to make it water-based.

The coating composition of the present invention obtained in each example was coated onto an iron plate and a glass plate using a doctor blade so that the dry film thickness was 20 μm, and dried at room temperature for 7 days. Each glass plate was obtained.

Table 1 shows the results of tests conducted using painted iron plates and glass plates for testing according to the test method for coating film performance shown below.

Test method for paint film performance Pencil hardness: Measure the pencil hardness of a paint film painted on an iron plate.

Bending test: Mandrel diameter 1 for coating film painted on iron plate
cI! Observe the state when bent 180° with L bending tester.

Water was placed on the painted surface of a water-resistant steel plate and the change in the paint film was observed after 2 hours.

Gasoline was placed on the painted surface of a gasoline-resistant glass plate and the condition was observed after it evaporated.

Gloss T-observation with two eyes.

Place the test piece horizontally with the painted surface facing upward in an indirect hot air oven adjusted to 0°C, and apply 5011N to the center of the painted surface.
Stack 5 square pieces of gauze and place a 40mm diameter, 500g weight in the center. After 1 hour, take it out and pull the gauze away from the painted surface.

Check the degree of adhesion between the painted surface and the gauze and the traces of the texture on the painted surface.

Texture: 2. Touch the painted surface with your finger at a temperature of 20°C and a relative humidity of 75% to examine the surface's scratchiness.

Abrasiveness: After polishing the painted surface 10 times with No. 400 water-resistant abrasive paper, examine the abrasive paper to see if it has any blemishes.

The coating film performance test results were evaluated in four stages: ◎, ○, △, and ×. ○～◎ are practical.

Δ to × are impractical.

Table 1 [Effects of the Invention] The aqueous coating resin composition containing the cellulose derivative of the present invention is sticky because it does not contain an emulsifier.

Solvent resistance and abrasion resistance (1) It is possible to form a coating film with excellent mechanical strength, and (1) it has excellent dispersion stability, so it has the advantage of being able to significantly reduce the organic solvent content by removing the solvent.

Agent Patent Attorney Katsutoshi Takahashi

Claims (1)

[Claims] 1. (1) (a) Hydroxyl group-containing cellulose derivative 90.0
0 to 99.95% by weight and (b) 0.0 to 99.95% by weight of acrylic anhydride and/or methacrylic anhydride.
(2) 95 to 5 parts by weight of a polymerizable vinyl monomer containing at least 2% by weight of a carboxyl group-containing vinyl monomer; An aqueous coating resin composition comprising a copolymer of the above dispersed in an aqueous medium. 2. The aqueous coating resin composition according to claim 1, wherein the hydroxyl group-containing cellulose derivative is an ester-modified hydroxyl group-containing cellulose derivative or an ether-modified hydroxyl group-containing cellulose derivative. 3. The aqueous coating resin composition according to claim 1, wherein the hydroxyl group-containing cellulose derivative is cellulose acetate butyrate. 4. The number average molecular weight of the hydroxyl group-containing cellulose derivative is 3,
The aqueous coating resin composition according to claim 1, 2 or 3, which has a molecular weight in the range of 000 to 300,000. 5. The aqueous coating resin composition according to claim 1, 2, 3 or 4, wherein the content of hydroxyl groups in the hydroxyl group-containing cellulose derivative is 0.4% by weight or more. 6. The aqueous coating resin composition according to claim 1, wherein the carboxyl group-containing vinyl monomer is selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid. 7, (1) (a) Hydroxyl group-containing cellulose derivative 90.0
0 to 99.95 parts by weight and (b) 0.0 to 99.95 parts by weight of acrylic anhydride and/or methacrylic anhydride.
(2) a polymerizable vinyl monomer containing at least 2% by weight of a vinyl monomer containing a carboxyl group; A first step of producing a carboxyl group-containing modified polymer by copolymerizing 95 to 5 parts by weight in the presence of a polymerization initiator, and at least one of the carboxyl groups contained in the carboxyl group-containing modified polymer. It consists of a second step of neutralizing a portion with a basic compound and then finely dispersing the neutralized product in water, at which time the amount of the basic compound used is such that the pH of the dispersion becomes 5 or more. A method for producing a resin composition for aqueous coating, characterized by: 8. The method for producing an aqueous coating resin composition according to claim 7, wherein the hydroxyl group-containing cellulose derivative is an ester-modified hydroxyl group-containing cellulose derivative or an ether-modified hydroxyl group-containing cellulose derivative. 9. The method for producing an aqueous coating resin composition according to claim 7, wherein the hydroxyl group-containing cellulose derivative is cellulose acetate butyrate. 10, the number average molecular weight of the hydroxyl group-containing cellulose derivative is 3
10. The method for producing an aqueous coating resin composition according to claim 7, 8 or 9, wherein the aqueous coating resin composition is in the range of ,000 to 300,000. 11. Claim 7, 8, 9 or 10, wherein the content of hydroxyl groups in the hydroxyl group-containing cellulose derivative is 0.4% by weight or more.
The method for producing the aqueous coating resin composition described above. 12. The method for producing an aqueous coating resin composition according to claim 7, wherein the carboxyl group-containing vinyl monomer is selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid. 13. A paint comprising the aqueous coating resin composition according to claim 1.