JPS6187761A - Paint containing spherical epoxy particle - Google Patents

Abstract

PURPOSE:To provide the titled paint which hardly causes precipitation of fine particles and has a matte effect exhibiting transparent appearance, containing fine spherical epoxy particles which have been cured by an amine hardener. CONSTITUTION:4-30wt% nonionic surfactant having an HLB of 10 or above (e.g. polyoxyethylene phenol-substd. ether surfactant) is added to an epoxy compd. contg. at least two epoxy groups per molecule (e.g. bisphenol A glycidyl ether epoxy resin). The mixture is heated at room temp. to 95 deg.C and water is added thereto with rapidly stirring to obtain an epoxy emulsion. 0.2-1.2 equivalents of an amine hardener (e.g. ethylenediamine) is added to the emulsion to cure the epoxy compd., thus containing fine spherical epoxy particles. The epoxy particles are then dispersed in a soln. of a paint resin such as alkyd resin or acrylic resin in an org. solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a paint containing epoxy spherical particles.

[Conventional technology]

Japanese Patent Publication No. 55-42360 discloses a technique for obtaining bispherical particles by curing a mixture of an epoxy compound and a curing agent in water. Further, JP-A-53-73249 discloses a technique for obtaining fine powder from a mixture of an epoxy resin, an interfacial thickening agent, a curing agent, and water.

[Problem that the invention seeks to solve]

Paints contain inorganic pigments for the purpose of matting or coloring, but these generally have a large specific gravity and tend to settle. Therefore, during use, it is necessary to stir well to disperse the blended particles. Furthermore, since inorganic particles generally have a large refractive index, they are convenient for creating a sense of opacity, but it is difficult to achieve a special paint finish such as a transparent matte effect.

The present invention aims to solve the drawbacks of these inorganic particles.

Measures to solve problem C] The present invention is configured as follows.

A paint containing epoxy spherical particles obtained by curing an epoxy compound emulsion into particles with an amine curing agent.

The details of the present invention will be sequentially explained below. First, the method for producing 9 epoxy spherical particles and particles used in the present invention will be explained.

The epoxy compound used to produce the epoxy spherical particles is preferably one containing two or more epoxy groups in nine molecules. Examples include glycidyl etherified bisphenol A type compounds at both ends, diglycidyl ethers of polyethylene glycol, polyglycidyl ethers of phenol novolak type compounds, N, M, N/
, N/-tetraglycidyl m-xylene diamine, etc., which can be used alone or in combination.

Furthermore, if necessary, it is possible to add a small amount of a compound 1 having one epoxy group in the molecule, such as glycidyl methacrylate. Also used in the present invention is a modified epoxy compound in which a part of the epoxy group is bonded to a compound having an amide 7 group or the like.

In the present invention, an epoxy compound emulsion as described above is formed.

The surfactant used in the present invention preferably has an HLB value of 10 or more. When the HLB value is lower than this, the stability of the emulsion is impaired when the emulsified epoxy particles are cured into particles with a curing agent, and a good particulate cured product tends not to be obtained. Types of emulsifiers that can be particularly preferably used in the present invention include ether-type nonionic surfactants such as polyoxyethylene/phenol-substituted ether type and polyoxyethylene-based polyoxypropylene block O polyether type. These include ester-type nonionic surfactants such as higher fatty acid esters of polyethylene glycol and fatty acid esters of polyhydric alcohols, and alkoxylated rosins. Also.

Examples include those that are self-emulsifying and act as curing agents for epoxy compounds, such as polyamide amines, which are reaction products of timer acid and polyether diamine or aliphatic polyamine.
When its HLB value is 10 or more, it is preferably used in the present invention.

The amount of emulsifier used is also important in the present invention. The emulsifier is preferably added in an amount of 4 weight percent or more based on the uncured epoxy compound. When the amount of emulsifier is less than this, the stability of the uncured epoxy emulsion tends to decrease, making it difficult to obtain a good particulate cured product. The upper limit of the amount of emulsifier to be used is not particularly limited, but it is generally preferably 60% by weight or less relative to the uncured epoxy compound in order to prevent deterioration of the physical properties of each particle.

The uncured epoxy emulsion particles of the present invention may contain other additives as long as they do not impair the present invention. The most typical additives are organic and inorganic pigments and dyes used to color or opacify epoxy particles.

Antistatic agents, conductive agents, ultraviolet absorbers, etc. can also be added depending on the purpose. These additives are usually added before emulsifying the uncured epoxy compound and are incorporated by thorough mixing or dissolution.

Generally, the difficulty of emulsifying a compound is affected by its viscosity. When the epoxy compound has a high viscosity or is a type of epoxy compound that solidifies at room temperature.

It is difficult to emulsify sufficiently using mechanical force alone. In such cases, an epoxy compound diluent is used along with an emulsifier.

Diluents include ketones, alcohols, cellosolves,
Examples include dioxane, aromatic hydrocarbons, and esters such as ethyl acetate.

As described above, the epoxy composition prepared using the epoxy compound and the emulsifier as its basic composition is then emulsified according to a conventional method to form an uncured epoxy emulsion. Although the emulsification method is not particularly limited, two representative methods are shown below.

The above epoxy composition containing an emulsifier is heated to room temperature to 95°C, and water in the above temperature range is gradually added thereto while stirring at high speed. It is generally preferable to add water intermittently rather than continuously, and a method in which addition periods and periods in which only stirring is performed is alternated is recommended.

Epoxy emulsions are given stability in water by the action of emulsifiers, such as hydroxyethyl cellulose and carboxymethyl cellulose.

It is also effective to add a substance exhibiting protective colloidal action to water in advance, such as gum arabic or polyvinyl alcohol, to increase the stability of the emulsion.

The method for curing the emulsion particles of the epoxy compound obtained as described above into particles is as follows.

There are two methods: (1) a method in which an amine curing agent is added to an epoxy compound in advance and then emulsified; and (2) a method in which a water-soluble amine curing agent is added to an emulsion.

For the former method, ethylenediamine, diethylenetriamine, N(2-aminoethyl)piperazine, and the like, which are liquid at room temperature, are suitable as curing agents.

Approximately 0.2 to 1.2 equivalents of these curing agents are added to an epoxy compound containing a surfactant and emulsified.

In the latter method, a water-soluble amine curing agent is added to the uncured epoxy emulsion obtained as described above to harden the emulsion particles into particles to prepare epoxy fine particles.

The latter method will be explained in detail below.

The amine curing agent used in the present invention is prepared by mixing a stoichiometrically calculated amount of amine with an uncured epoxy compound at room temperature, and after leaving it at room temperature for 8 hours, the Shore A hardness of the mixture is 5.
It is preferable that the amine compound is an amine compound characterized in that it is 0 or more.

If the Shore A hardness is less than this value, the curability of the uncured epoxy emulsion will decrease.

There is a tendency that a good particulate cured product cannot be obtained.

Note that the normal temperature here refers to 20°C.

Examples of the curing agent that can be used in the present invention include the following compounds, but are not particularly limited thereto. These include polyethylene polyamines such as piperazine, hydrazine, ethylenediamine, diethylenetriamine, and triethylenetetramine, alcohol amines such as monoethanolamine, and N(2-aminoethyl)piperazine.

The present invention is achieved by adding an amine curing agent that satisfies the Shore A hardness conditions described above to the uncured epoxy compound emulsion, and the amount of the curing agent used is important in the invention. In the present invention, the amine compound is preferably 0.3 equivalent or more as calculated stoichiometrically from the epoxy value of the uncured epoxy compound emulsion. When the amount of the curing agent used is less than this, the curability of the uncured epoxy emulsion tends to decrease, making it difficult to obtain a good particulate cured product.

The upper limit of the use of the above curing agent is not particularly limited, but as the stability of the emulsion decreases as the amount used increases, it is generally calculated stoichiometrically from the epoxy value of the uncured epoxy compound emulsion. 4 equivalents or less of amine is preferred.

In the present invention, it is also possible to use one or more amine curing agents as the curing agent added to the uncured epoxy compound emulsion. In particular, when used in combination with piperazines and hydrazines, good particulate cured products are often obtained.

After adding the water-soluble amine curing agent, the curing reaction proceeds while the whole is left standing or gently stirred.

If necessary, the particles after curing can be subjected to heat treatment to post-cure residual epoxy groups, acid treatment to neutralize amino groups in the particles, or dyeing treatment.

A typical method for producing a paint containing the epoxy-based Kyuhorihoko obtained as described above will now be described.

If the paint is based on an organic solvent, the epoxy-based spherical particles are added to a solution of an organic solvent such as toluene, ethyl acetate, or butyl acetate in which a paint resin such as alkyd resin, acrylic resin, polyurethane resin, or epoxy resin is dissolved. If so, it is also possible to add it directly. When epoxy spherical particles are substituted with a dispersion medium from an aqueous slurry and previously dispersed in an organic solvent and then blended into a coating material, a product with particularly good dispersibility can be obtained.

The following methods can be used to replace the water slurry of epoxy spherical particles with a dispersion medium.

(1) Filter the water slurry and redisperse it in a highly hydrophilic organic solvent such as alcohols or acetones while it is still dry. For redispersion, it is preferable to use a stirrer such as a homogenizer or mixer. Alternatively, instead of filtration, it is possible to centrifuge, discard the supernatant, and add an organic solvent.

(2) Repeat the above operation until the water component is virtually eliminated. In this process, drying of the particles is avoided as much as possible, and the particles are redispersed in an organic solvent while still in a wet state.

(3) For strongly lipophilic solvents such as benzene and liquid paraffin, the solvent is replaced with a lipophilic solvent via a hydrophilic solvent. In this case, the hydrophilic solvent must be mutually miscible with the lipophilic solvent.

When the paint is water-based, an aqueous slurry or dry powder of epoxy spherical particles is added and dispersed in a resin emulsion such as an acrylic resin emulsion, an epoxy resin emulsion, or a polyurethane resin emulsion.

The preferred blending amount of epoxy spherical particles is about 0.5 to 150% by weight relative to the resin content in the paint; if it is less than this, the effect of blending will be small, and if it is more than this, the strength of the coating will decrease. There is a tendency to

The average particle size of the epoxy spherical particles suitable for the present invention is about 1 to 500 μm, and the optimum particle size varies depending on the application.

Note that the paint containing the epoxy-based fine particles can contain inorganic pigments such as titanium oxide and calcium carbonate, organic pigments, etc. within a range that does not impair the present invention.

〔Example〕

Example 1 10 g of a commercially available Nobisphenol A glycidyl ether type epoxy resin (Epicoat 828, manufactured by Yuka Shell Epoxy) was placed in a 100 cc polycup, and HLB was added to the cup.
0.8 g of Neugen KA-137 (manufactured by Dai-Kogyo Co., Ltd.), which is a commercially available polyoxyethylene phenol-substituted ether emulsifier of No. 13, was added. The mixture was kneaded at 800 rpm for 1 minute using a stirring rod equipped with a Teflon plate blade at the tip. Subsequently, 1.5 cc of water in a syringe was sequentially added at 1 minute intervals while stirring at 800 rpm to form an emulsion.

8 cc of water containing 0.8 equivalents of piperazine was added to this epoxy emulsion and stirred uniformly. A curing reaction was carried out for 5 days at 25° C. to form particles. The obtained particles were perfectly spherical with an average particle diameter of 6.5 μm.

After filtering and washing the slurry of epoxy spherical particles containing the curing liquid, the filter cake was heated to 300W bee power and heated to 200C.
C water and 41 H, 5o410 oc were added and heat treated at 90° C. for 2 hours while stirring to eliminate unreacted epoxy groups remaining in 1 particle and improve the solvent resistance of 9 particles.

Slurry of epoxy spherical particles after the above treatment! After filtering and washing, the filter cake was taken in a 300cc peaker. Add 100 countries of ethyl alcohol to this.

The mixture was well dispersed using a mixer to complete the first stage of dispersion medium replacement. Subsequently, this dispersion was filtered, redispersed in ethyl alcohol, and filtered twice to obtain a slurry (concentration: 25% by weight) of epoxy spherical particles well dispersed in toluene.

A polyester resin for paint was manufactured using the following recipe.

Flaxseed oil fatty acid 536 parts Maleic anhydride 72.5 parts Phthalic anhydride 87 parts Glycerin 92 parts Ethylene glycol monoethyl ether 300 parts 20
Heat at 0°C for 2 hours.

A paint was produced by mixing the above slurry of epoxy spherical particles, a polyester resin for paint, and a metal dryer (cobalt naphthenate) according to the following formulation.

Epoxy spherical particles 2-0 parts Polyester resin 40 parts Cobalt naphthenate 0.008 parts Toluene 40 parts Epoxy spherical particles have little sedimentation over time.

The epoxy spherical particles were well dispersed throughout even without mixing for several days.

When this paint was applied to an iron plate and allowed to dry, it created a warm white finish.

Example 2 10 g of a commercially available 7-enol novolak epoxy resin (Epicoat 154, manufactured by Yuka Shell Epoxy) was heated at 100o.
c Put it in a polycup and add 0 of Neugen HA-137 to it.
．． Add 8g and emulsify at 80℃.

Subsequently, 8α water containing 1.2 equivalents of piperazine was added as a hardening liquid. The mixture was left standing at 25° C. for 6 days to obtain spherical particles with an average particle diameter of about 8 μm.

After heat treatment was performed in the same manner as in Example 1, nine particles were filtered, washed, and dried.

A lacquer containing the above epoxy spherical particles was prepared with the following formulation.

1/2 second nitrocellulose (wet with 35 thiol) 20 parts dibutyl phthalate 5 parts epoxy spherical particles
5 parts butyl acetate 30 parts butanol 10 parts toluene
There was almost no sedimentation of the 30 parts epoxy particles over time.

When applied on a brass plate and dried, a beautiful white finish was obtained.

〔Effect of the invention〕

According to the present invention, a paint can be produced in which the matting agent added for matting does not settle during storage and has a unique finish.

Procedural amendment 60.11. -6 Showa year month day

Claims (1)

[Claims] A paint containing epoxy spherical particles obtained by curing an epoxy compound emulsion into particles with an amine curing agent.