JPH0465871B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a new aqueous aerosol coating.
More specifically, the present invention relates to a new water-based aerosol paint that is mildly flammable and does not fall under the category of hazardous materials under the Fire Service Act. In general, solvent-based aerosol paints dissolve natural or synthetic resins as vehicle components in a solvent.
A propellant is mixed with this, pigments and additives are added, and these are placed in a spray container, but a large amount of organic solvents such as toluene, ethyl acetate, and methyl ethyl ketone are used to dissolve the resin. There is. However, these solvents are extremely flammable, with both flame length and explosive limit (according to Ministry of International Trade and Industry Notification No. 557), making them not only dangerous to handle, but also harmful to the human body, and are often used during manufacturing. Solvent-based aerosol paints have had many drawbacks in handling and use, such as being a source of pollution. In addition, there are some aerosol paints that use chlorinated solvents such as trichloride and perchlorene as solvents and fluorocarbons as propellants to make them less flammable, but both the solvent and propellant are toxic. However, it has problems such as ozone destruction and ozone destruction, and is therefore unsatisfactory as a low-flammability aerosol paint. Focusing on these points, various attempts have been made to use water-based resins as vehicles in order to make aerosol paints less flammable or non-flammable. For example, JP 54-31445, 54-32540, 54-
As seen in 32541, 54-33545, 54-33546, etc.
Various water-based aerosol paints have been considered. However, the vehicles considered for use in these applications are, for example, emulsion resins or water-dispersed resins that thicken upon contact with water-soluble propellants, or water-soluble acrylic resins, alkyd resins, and modified alkyd resins. , melamine-modified alkyd resins, amino resins, emulsion-polymerized vinyl acetate emulsions, acrylic emulsions, etc., each of which has its own drawbacks. For example, in the case of emulsion resins or water-dispersed resins that thicken when they come into contact with water-soluble propellants, the resin composition is extremely limited in the solvents that can be used, and the paint viscosity also depends on the ratio of resin and solvent. It has the disadvantage that good results can only be obtained with a very limited range of paint formulations because the paint composition changes easily. Also,
For water-soluble acrylic resins, modified alkyd resins, melamine modified alkyd resins, amino resins, etc., in order to make the paint less flammable, it is necessary to increase the amount of water as a diluent, but this may result in poor atomization. Therefore, pinholes, sagging, etc. are likely to occur due to foaming of the coating film, which is undesirable. In addition, emulsion-polymerized vinyl acetate emulsions, acrylic emulsions, and the like tend to settle, gel, thicken, etc. in containers during storage, and have drawbacks such as significant foaming immediately after coating. For this reason, when using such water-soluble resins or emulsions produced by emulsion polymerization, the mixed solvent used as a diluent can only have a very limited composition, and the composition of the resin also changes accordingly. Therefore, it has been extremely difficult to produce a practically useful low-flammability aerosol paint that is applicable to a wide range of resin compositions and paint compositions. The present inventors conducted intensive research to solve these problems, and found that the composition by weight is 5 to 30% of an aqueous acrylic dispersion as a vehicle component, 30% or less of water as a solvent, and a water-soluble organic In an aqueous aerosol paint comprising a component consisting of 40% or less of a solvent and 30 to 70% of a propellant as 100, and a pigment of 0.1 to 25%, the acrylic resin aqueous dispersion contains 1
~15% by weight of a hydrophilic monomer A having a polyoxyethylene chain having a molecular weight of 1,500 to 15,000 and having one polymerizable vinyl group in the molecule and whose terminal group is H or a C _1-4 alkyl group. , characterized in that it is formed by dispersing in water a resin solution obtained by polymerizing 99 to 85% by weight of other polymerizable vinyl monomers in a water-soluble organic solvent solution. Provided herein is a novel water-based aerosol paint that does the following: The aqueous acrylic resin dispersion used in the present invention does not use commonly used emulsifiers or protective colloids, but is made by stably dispersing polymers polymerized by solution polymerization in water through the action of water-soluble solvents and new water groups. It is an aqueous dispersion. The aqueous aerosol paint using the aqueous acrylic resin dispersion obtained according to the present invention has disadvantages of water-soluble resins, namely, foaming of the coating film due to poor atomization when the amount of water as a diluent is increased. There are no problems such as pinholes or dripping, and when using emulsion-polymerized vinyl acetate emulsion or acrylic emulsion, sedimentation, gelation, thickening, etc. may occur in the container during storage, or immediately after painting. The occurrence of foaming and the like is also improved, and a wide range of monomer compositions and solvent compositions can be applied, which is extremely advantageous in practice. The aqueous acrylic resin dispersion used in the present invention has a molecular weight in which the molecule has one polymerizable vinyl group and the terminal group is H or a C _1-4 alkyl group.
A hydrophilic monomer A having a polyoxyethylene chain of 1500 to 15000 and another polymerizable vinyl monomer are polymerized in a water-soluble organic solvent solution at a ratio of 1 to 15% by weight of the former and 99 to 85% by weight of the latter, It is then obtained by dispersing it in water. Examples of the hydrophilic monomer A having a polyoxyethylene chain having a molecular weight of 1500 to 15000 and having one polymerizable vinyl group in the molecule and a terminal group being H or a _C1-4 alkyl group include, for example, β- A compound whose polyoxyethylene chain has a molecular weight of 1500 to 15000, produced by adding ethylene oxide to a vinyl monomer containing a hydroxy group such as hydroxyethyl acrylate, β-hydroxypropyl acrylate, and β-hydroxyethyl methacrylate; molecular weight 1500 -15,000 polyoxyethylene glycol in which one end group is H or a C _1-4 alkyl group and the other end group is a hydroxy group containing vinyl groups such as acrylic acid, methacrylic acid, itaconic acid, and cinnamic acid. A compound produced by esterification reaction with a carboxylic acid monomer; the above polyoxyethylene glycol is combined with a vinyl group-containing ester monomer such as methyl acrylate, ethyl acrylate, methyl methacrylate, propyl acrylate, or butyl acrylate. Examples include compounds produced by transesterification. In the thus obtained hydrophilic monomer A having a polyoxyethylene chain having a molecular weight of 1500 to 15000 and having one vinyl group in the molecule and the terminal group being H or a C _1-4 alkyl group, The molecular weight of the polyoxyethylene moiety is from 1,500 to 15,000. If the molecular weight of the polyoxyethylene part is less than 1500, sufficient effect of water dispersion of the acrylic resin solution obtained by copolymerization will not be observed, and if the molecular weight of the polyoxyethylene part is less than 1500,
When it exceeds 15,000, the number of vinyl groups that can be copolymerized per unit molecular weight of the monomer becomes extremely small, and in this case also, the water dispersion effect of the acrylic resin solution obtained by copolymerization is significantly reduced. The molecular weight of the polyoxyethylene portion of the hydrophilic monomer is preferably 2,000 to 10,000, more preferably 3,000 to 8,000. The amount of the hydrophilic monomer A used is 1 to 15% by weight based on 99 to 85% by weight of other polymerizable monomers to be copolymerized. If the amount of hydrophilic monomer A used is less than 1% by weight, the resulting acrylic resin solution will not have a sufficient water dispersion effect, making it difficult to obtain a stable aqueous dispersion. Furthermore, even if the amount of hydrophilic monomer A exceeds 15% by weight, it is uneconomical because the water dispersing power of the resulting acrylic resin solution no longer increases significantly, and moreover, the water resistance etc. of the resulting polymer decreases. do.
A particularly preferred amount of hydrophilic monomer A is 2 to 10% by weight based on 98 to 90% by weight of other polymerizable monomers to be copolymerized. Other polymerizable vinyl monomers copolymerized with the hydrophilic monomer A include ethylenically unsaturated monomers. For example, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, lauryl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, (meth)acrylate.
2-hydroxypropyl acrylate, 2-hydroxy-3-chloropropyl (meth)acrylate,
Acrylic acid esters and methacrylic acid esters such as (meth)acrylic acid glycidyl ether;
α- such as acrylic acid, methacrylic acid, crotonic acid, etc.
or β-unsaturated carboxylic acids or salts thereof; α- or β-unsaturated amides such as acrylamide, methacrylamide, N-methylacrylamide, N-methylolacrylamide; unsaturated nitriles such as acrylonitrile and methacrylonitrile; It will be done. In addition, vinyl chloride, vinylidene chloride, halogenated vinyl such as fluorine-containing monomers used in various water and oil repellents, etc.; styrene, Styrene derivatives such as α-methylstyrene and vinyltoluene; Vinyl esters such as vinyl acetate and vinyl propionate; Conjugated dienes such as α-olefin and butadiene; Copolymerization of maleic anhydride, maleic esters, and ethylene, etc. can be done. Further examples include cationic monomers such as dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate. In the present invention, hydrophilic monomer A is copolymerized with one or more of these. Copolymerization of hydrophilic monomer A and other polymerizable vinyl monomers is carried out in a water-soluble organic solvent solution,
An acrylic copolymer resin solution is created. Examples of the water-soluble organic solvent used include isopropyl alcohol, n-propoxypropanol,
diacetone alcohol, isobutyl alcohol,
Alcohols such as n-butyl alcohol; propylene glycol monomethyl ether, methyl cellosolve, ethyl cellosolve, ethylene glycol monoisopropyl ether, butyl cellosolve, diethylene glycol monomethyl ether,
Examples include ether alcohols and ethers such as dioxane. The amount of the above water-soluble organic solvent used is not particularly limited, but usually
It is used in an amount of 10 to 100 parts by weight per 100 parts by weight of the vinyl monomer to be copolymerized. In any case, when obtaining an acrylic copolymer resin solution, benzoyl peroxide, lauroyl peroxide, di-
Organic peroxides such as tert-butyl peroxide, tert-butyl perbenzoate, tert-butyl peroctoate acetyl peroxide, or 2,2'-azobisisobutyronitrile, 2,2'-azo So-called radical initiators such as nitrile-based initiators such as bisvaleronitrile can be used. The method for preparing the acrylic copolymer resin solution is not particularly limited, and a radical initiator is The monomer to be copolymerized may be added dropwise, or the monomer to be copolymerized in which the radical initiator and hydrophilic monomer A are dissolved may be added dropwise while heating and stirring a water-soluble organic solvent. The monomer to be copolymerized with the organic solvent and the radical initiator may be added simultaneously with the hydrophilic monomer A, or the monomer to be copolymerized with the radical initiator may be added dropwise in the latter half of the polymerization with the radical initiator in the water-soluble organic solvent. It is also possible to add monomer A to the mixture. The aqueous acrylic resin dispersion used in the present invention is prepared by mixing the acrylic copolymer resin solution prepared as described above and water. Dispersion of acrylic copolymer resin solution in water is as follows:
Either of the methods of gradually adding and dispersing the resin solution into water while stirring, or conversely, the method of gradually adding water to the acrylic copolymer resin solution and performing phase inversion emulsification are possible. In general, a method of heating an acrylic copolymer resin solution to about 50 to 100°C and gradually adding water dropwise while stirring well to effect phase inversion emulsification is
This is a preferred method because a stable aqueous acrylic resin dispersion having a fine particle size can be easily obtained. The aqueous acrylic resin dispersion used in the present invention has a non-volatile content of 20-60% by weight, preferably 30-50% by weight, and a viscosity (cps) of less than 3000. If necessary, part or all of the acid component of the aqueous acrylic resin dispersion can be neutralized with a volatile alkali such as ammonia or morpholine. Neutralization can be carried out by dissolving an alkali in the water added during the preparation of the aqueous dispersion, or by
This is done by adding an alkali after the preparation of the aqueous dispersion. The aqueous aerosol paint of the present invention contains 5 to 30% by weight of the thus obtained aqueous acrylic resin dispersion and 30% by weight of water.
Weight% or less, water-soluble organic solvent 40% or less and propellant
The component consisting of 30 to 70% is set as 100, and pigment is added to this.
It is created by blending 0.1 to 25% by weight.
Examples of the water-soluble organic solvents used as diluting solvents for water-based aerosol paints include methanol, ethanol,
Alcohols such as butanol, propanol, isopropanol; Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone; Esters such as methyl acetate, ethyl acetate; methyl cellosolve, ethyl cellosolve, butyl cellosolve,
Examples include ethers such as methyl cellosolve acetate alone or in mixtures. The above-mentioned propellant is selected from one that is a gas at room temperature, satisfies properties such as spray suitability and stability, and has good compatibility with the acrylic resin aqueous dispersion and diluting solvent. Typical examples are trichloromonofluoromethane, dichloromonofluoromethane,
Halogenated hydrocarbons such as dichlorofluoroethane. In addition, dimethyl ether, liquefied petroleum gas (LPG), a mixture of dimethyl ether and liquefied petroleum gas, in an amount that maintains weak flammability when combined with the aqueous acrylic resin dispersion and diluting solvent during aerosol paint injection. etc. can also be used. In order to improve the quality stability and long-term storage properties of water-based aerosol paints, known additives such as matting agents, anti-settling agents, defoaming agents, anti-sagging agents, and rust preventive agents are added. is also possible. In the aqueous aerosol paint of the present invention, the composition ratio of the acrylic resin aqueous dispersion, water, water-soluble organic solvent, and propellant is determined to meet the properties required for an aqueous aerosol paint, that is, the above-mentioned mist forming property, good sprayability, In order to satisfy the compatibility with the propellant, etc., and to make the water-based aerosol paint weakly flammable and not similar to dangerous substances under the Fire Service Act, the weight composition of the aqueous acrylic resin dispersion is 5 to 30%.
%, water 30% or less, water-soluble organic solvent 40% or less, propellant 30-70%. Particularly preferred ranges are 10 to 25% acrylic resin aqueous dispersion and 5 to 25% water.
20%, water-soluble organic solvent 5-35%, propellant 40-60%
It is. If the amount of water added exceeds 30%, it is not preferable because not only the drying speed of the sprayed coating film is slow, but also corrosion of the spray container is accelerated. If the amount of the water-soluble organic solvent added exceeds 40%, it is not preferable because it becomes a dangerous substance under the Fire Service Act when spraying the paint, and the slightly flammable aerosol paint that is the object of the present invention cannot be obtained. The amount of color pigment added varies depending on the type of pigment, such as white pigment, yellow pigment, blue pigment, etc.
Taking the above composition as 100, it can be blended arbitrarily in a range of 0.1 to 25% by weight, preferably 1 to 10%. Next, Examples will be given to specifically explain the present invention, but the present invention is not limited only to these Examples. Note that all parts and percentages in each example are based on weight. Synthesis Example 1 Into a second flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel, and an inert gas inlet, 300 parts of ethyl cellosolve as a solvent and 300 parts of ethyl cellosolve with a methoxy terminal group and a polyoxyethylene moiety having a molecular weight of
6000 methacrylic acid methyl ester derivative 35
The temperature was raised to 130°C in a nitrogen gas stream. Separately, 476 parts of metal acrylate, 210 parts of butyl acrylate, and 14 parts of methacrylic acid were weighed and mixed in advance as vinyl monomers, and tertiary butyl methacrylate was added.
Weigh out 14 parts and inject each from a separate dripping port to make 3 parts.
Polymerize dropwise uniformly over time. After completion of the dropwise addition, the temperature was further maintained at 130°C for 6 hours to complete the polymerization. The obtained solution was cooled to 80°C, and 615 parts of water was added dropwise at the same temperature over a period of about 2 hours. then 25
By cooling to .degree. C., a uniform aqueous acrylic resin dispersion with a slight bluish tinge was obtained. This aqueous acrylic resin dispersion was adjusted to be alkaline with 5% aqueous ammonia. This dispersion has a non-volatile content
45.1%, viscosity 1150cpsPH8.2, and average particle size 0.2μ or less. Synthesis Examples 2 to 6 The solvent used, the type and amount of the hydrophilic monomer A containing one vinyl group in the molecule whose polyoxyethylene moiety has a molecular weight of 1500 to 15000, and the polymerizable vinyl monomer to be copolymerized. Synthesis Example 1 was repeated except that the type and amount were varied. The results were as shown in Table 1.

【table】

[Table] Comparative Synthesis Example 1 In order to perform a performance comparison with an acrylic emulsion polymer obtained by emulsion polymerization, an emulsion polymer having the following composition was prepared by a conventional emulsion polymerization method. Methyl methacrylate 476 parts Butyl acrylate 210 Methacrylic acid 14 Sodium dodecylbenzenesulfonate 28 Ammonium persulfate 2.1 Ion exchange water 1094.8 total 1824.9 parts The obtained emulsion has properties of nonvolatile content 40.2%, viscosity 215 cps, and pH 3.6. Was. Comparative Synthesis Example 2 In order to perform a performance comparison with an acrylic water-soluble resin, the following composition was polymerized in a solvent by a conventional method, and then neutralized and diluted with water. Methyl methacrylate 350 parts Butyl acrylate 280 Methacrylic acid 70 Butyl cellosolve 490 Tert-Butyl peroxybenzoate 7 Triethylamine 84 Ion exchange water 490 total 1771 parts The obtained water-soluble resin had a non-volatile content of 40.5% and a viscosity of
Its properties were 23,000 cps and PH of 9.4. Examples 1 to 7 and Comparative Examples 1 to 4 Water, a water-soluble organic solvent, and a pigment were added to the acrylic resin aqueous dispersion obtained in the synthesis example and the emulsion polymer and water-soluble resin obtained in the comparative synthesis example, respectively. The aqueous aerosol paints listed in Table 2 were prepared by adding and mixing uniformly to obtain a solution of a specified resin viscosity, charging it into a spray container, and filling it with a propellant. Their performance is shown in the same table. Reference Example Conventional solvent-based aerosol paints having the following composition were tested, and the results are also listed in Table 2. Solvent type acrylic resin 7.6% CAB resin 12.5% Organic mixed solvent 21.9% Plasticizer 0.2% Titanium white 2.7% Propellant (LPG) 55.1% Total 100%

【table】

[Table] The water-based aerosol paints of the present invention of Examples 1 to 7 are as follows:
All of them are mildly flammable, and their sprayability, foaming properties, and other properties are equivalent to or better than those of solvent-based aerosol paints. Excessive dilution (water or water-soluble organic solvent) as in Comparative Examples 1 and 2 is unfavorable in terms of anti-sag properties and strong flammability during spraying. In addition, when using an acrylic resin emulsion obtained by emulsion polymerization as in Comparative Example 3, the stability of the paint becomes extremely poor due to the addition of a water-soluble organic solvent, and it also has foaming properties when sprayed. This is not desirable as it is significant. Aerosol paints made using water-soluble acrylic resins such as Comparative Example 4 are not preferred because they cause significant sagging of the paint film when sprayed. The solvent-based aerosol paint shown as a reference example is highly flammable and therefore poses many problems in handling. The water-based aerosol paint of the present invention is a water-based aerosol paint that has a quality equal to or higher than that of conventional solvent-based aerosol paints and is easy to handle. Also,
According to the present invention, even when an aqueous acrylic resin dispersion, various water-soluble organic solvents, and water are mixed in a wide range of composition ratios, which was previously difficult, it is relatively safe to handle and use due to its low flammability. A water-based aerosol paint is provided which has the great advantage of not requiring special facilities even when stored in large quantities.

Claims (1)

[Claims] 1 Weight composition: 5 to 30% of an aqueous acrylic dispersion as a vehicle component, 30% or less of water as a solvent, 40% or less of a water-soluble organic solvent, and 30 to 70% of a propellant.
The component consisting of is 100, and the pigment is 0.1 to 25.
% of the aqueous aerosol paint, the acrylic resin aqueous dispersion contains 1 to 15% by weight of alkyl having one polymerizable vinyl group in the molecule and having H or C _{1 to 4} alkyl terminal groups. The molecular weight of the base is 1500~
Dispersing in water a resin solution obtained by polymerizing hydrophilic monomer A having 15,000 polyoxyethylene chains and 99 to 85% by weight of other polymerizable vinyl monomers in a water-soluble organic solvent solution. A novel water-based aerosol paint characterized in that it is formed by.