JPS6172017A - Production of epoxy spherical particles - Google Patents

Abstract

PURPOSE:An epoxy compound emulsion which is obtained by emulsifying in the presence of a protective colloid is combined with a water-soluble amine and cured to give the particles which contain no surfactant and is used as a filler for rubber. CONSTITUTION:Emulsification is effected in the presence of (A) a protective colloid (preferably a water-soluble polymer, e.g., PVA) to give (B) an epoxy emulsion. The emulsion is combined with (C) a water-soluble amine such as piperazine and cured to give the objective particles. Component B is recommendably obtained by adding an epoxy compound such as bisphenol A glycidyl ether to the dispersant of component A gradually.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing fine spherical epoxy particles.The particles produced by the present invention are used in the following applications.

As a filler, reinforcing agent, and crosslinking agent for plastics and rubber.
Used as column packing material for chromatography. Particles colored by dyeing are used in color toners for electrostatic copying machines, colorants in cosmetics, detergents, toothpaste, hairspray, etc., and PH indicators. In addition, spherical particles can be used as spacers for liquid crystal display panels, spacers for uniform coating thickness of adhesives, abrasives for hard contact lenses, and microparticle diagnostic reagents. Particles encapsulating magnetic particles can be used as toner or carrier for electrostatic copiers, or as compounding agents for radio wave shielding paints such as carbon black, copper, nickel, etc.
Particles made conductive by enclosing silver or gold powder or by coating the surface with copper, nickel, silver, gold, etc. can be used as a compounding agent in radio wave shielding paints for plastics, rubber, paints, etc. It is used as a sex preparation.

[Conventional technology]

Japanese Patent Publication No. 53-42360 discloses a technique for obtaining spherical particles by curing a mixture of an epoxy compound and a curing agent in water. Furthermore, Japanese Patent Application Laid-Open No. 53-73249 discloses a technique for obtaining fine powder from a mixture of epoxy resin, surfactant, curing agent, and water.

[Problem that the invention seeks to solve]

The gist of the present invention is to harden an emulsion of an epoxy compound into particles. In the prior art, surfactants have generally been used to obtain emulsions of epoxy compounds. Therefore, there is a drawback that a part of the surfactant is incorporated into the particles after curing, which causes deterioration in the physical properties of the particles and changes in surface properties.

[Means for solving problems]

The present invention is configured as follows.

A method for producing epoxy-based spherical particles, which comprises adding and curing an emulsified epoxy compound in the presence of a protective colloidal substance. ! The details of the present invention will be sequentially explained below.

The epoxy compounds used in the present invention include:

Those containing two or more epoxy groups in the molecule are preferable, such as bisphenol A-type glycidyl ethers at both ends, diglycidyl ethers of polyethylene glycol, and polyglycidyl ethers of phenol novolac-type compounds. '-tetraglycidyl m-xylene diamine and the like, which can be used alone or in combination.

Furthermore, if necessary, it is possible to add a small amount of a compound 9 having one epoxy group in the molecule, such as glycidyl methacrylate. Also used in the present invention are modified epoxy compounds in which a part of the epoxy group is bonded to a compound having an amino group or the like.

In order to achieve the present invention, the above-mentioned epoxy compound is emulsified in water or an aqueous dispersion medium with the aid of a substance exhibiting a protective colloid action. The substance exhibiting a protective colloid effect used here is preferably a water-soluble polymer, such as polyvinyl alcohol, hydroxymethyl cellulose, carboxymethyl cellulose, gum arabic, and sodium polyacrylate.

A method for emulsifying the epoxy compound with the substance exhibiting protective colloid action is as follows.

Either water or an aqueous dispersion medium in which a protective colloid substance has been dissolved in advance is gradually added to a vigorously stirred epoxy compound, or conversely, an epoxy compound is added to a dispersion medium in which the above protective colloid substance has been dissolved and vigorously stirred. It is common to add compounds gradually.

The amount of the protective colloidal substance used in the present invention is 0.5% by weight or more, preferably 1% by weight or more based on the epoxy compound. If the amount used is less than this, the epoxy compound cannot be emulsified stably (it becomes impossible).As the amount of the protective colloid substance used increases, the average particle diameter of the spherical particles of the epoxy compound obtained tends to decrease. However, if the amount is too large, the viscosity of the dispersion medium increases, resulting in operational problems such as difficulty in handling.

Therefore, the amount of the protective colloid substance used is preferably 80% by weight or less based on the epoxy compound.

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 it sufficiently with just one mechanical force.

In such cases, an epoxy compound diluent is used together with an emulsifier.

Examples of the diluent 1 include ketones, alcohols, cellosolves, dioxane, aromatic hydrocarbons, and esters such as ethyl acetate.

Furthermore, emulsification can be carried out under elevated temperature conditions or cooling conditions for the purpose of increasing or decreasing the viscosity of the epoxy compound.

Further, in the present invention, it is also possible to use a surfactant or a powder emulsifier together with the protective colloidal substance. In this case, it is common to mix it with the epoxy compound in advance.

There is a close relationship between the concentration of an epoxy emulsion and the emulsion particle size and stability, and if the concentration is too low, aggregation tends to occur and stability deteriorates.

Generally, it is considered that a condition for obtaining a good emulsion is to adjust the emulsion concentration to about 10 to 80% by weight, but the present invention does not particularly limit this range. Furthermore, the emulsion of the epoxy compound of the present invention can also be dispersed in an aqueous dispersion medium outside of the wood assembly. The aqueous dispersion medium herein refers to an aqueous solution of an organic solvent that does not dissolve the epoxy compound used.

Next, the emulsion particles of the present invention can contain other additives within a range that does not impair the present invention.

The most typical additives are organic and inorganic pigments and dyes used to color epoxy particles. A blowing agent can also be used to make the fine particles porous and hollow. 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.

Also for some epoxy groups in epoxy compounds.

Compounds with reactive functional groups such as amino groups and phenolic OH groups such as epoxy groups 9 For example, P that exhibits ultraviolet absorbing ability
It is also possible to impart ultraviolet absorbing ability to the particles by using compounds to which -ami7benzoic acid or benzophenone compounds are chemically bonded in advance.

In order to achieve the present invention, an emulsion of an epoxy compound as described above is hardened into spherical particles using an amine compound.

The amine curing agent used in the present invention is prepared by mixing a stoichiometrically calculated equivalent amount of amine with an epoxy compound at room temperature,
Preferably, the amine compound is characterized in that the mixture has a Shore A hardness of 50 or more after being left at room temperature for 8 hours.

If the Shore A hardness is smaller than this value, the curability of the epoxy compound 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 preferably achieved by adding to the epoxy compound emulsion a water-soluble amine curing agent that satisfies the Shore A hardness conditions described above, but the amount of curing agent used is important in the invention. In the present invention, the amine compound is preferably used in an amount of 0.3 or more equivalents calculated stoichiometrically from the epoxy value of the epoxy compound emulsion.

When the amount of the curing agent used is less than this, the curability of the 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, the amine 4 is generally calculated stoichiometrically from the epoxy value of the epoxy compound emulsion. An equivalent amount or less is preferable.

Methods for curing emulsion particles of epoxy compounds into particles include (1) a method in which an amine curing agent is added to the epoxy compound in advance and then emulsified; a method in which a water-soluble amine curing agent is added to the +21 emulsion; There is.

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 the epoxy compound and emulsified. However, this method tends to result in poor emulsion stability.

In the latter method, a water-soluble amine curing agent is added to the epoxy compound 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.

In order to add the amine curing agent of the present invention to an epoxy compound emulsion, it is common to mix the curing agent directly into the emulsion, but it is added after being dissolved in a water-soluble organic solvent such as water or alcohol in advance. There is a way.

Another possible method for adding the curing agent is to add part or all of the curing agent in advance to the water used when emulsifying the epoxy compound, and then emulsifying the water using the same.

゛! The emulsion concentration during curing is not particularly limited, but is 5.
It is preferable that the amount is at least % by weight from the viewpoint of stability of the emulsion. However, if the emulsion concentration becomes too high, the chances of each particle coming into contact with each other will increase, making them more likely to aggregate during the curing reaction.

The emulsion concentration during curing is preferably 80% by weight or less. .

As a curing agent added to epoxy compound emulsion,
It is also possible to use one or more amine curing agents. In particular, when used in combination with piperazines and hydrazines, good particulate cured products are often obtained.

In the present invention, in order to obtain spherical particles by curing the epoxy compound emulsion with the above-mentioned amine curing agent, it is preferable to leave it stationary or to perform gentle stirring during the curing reaction. Moreover, it is also possible to heat or cool as necessary during curing.

After curing, the particles may be subjected to heat treatment to post-cure residual epoxy groups, acid treatment to eliminate unreacted epoxy groups remaining within the particles, neutralization of amino groups, or dyeing. It is also possible to do this.

The epoxy spherical particles are cured and prepared into spherical particles in one or more ways. If the hardened particles are separated from the water by filtration or centrifugation, they can be recovered in powder form. Epoxy-based spherical particles are prepared in a spherical form with a particle size of 0.1 to 1000 μm depending on manufacturing conditions, but if some aggregation occurs during curing, they may grow into non-spherical porous particles. Such non-spherical particles are often aggregates of millet-shaped spherical particles. Further, during static curing, the particles at the bottom may be crushed and change from an original spherical shape to a flattened spherical shape. Any shape with a force of 59 or more is characterized as unique to the present invention.

〔Example〕

Example 1 10 g of a commercially available bisphenol A diglycidyl ether type epoxy resin Epicoat 828 (manufactured by Yuka Shell Epoxy) was placed in a 100 cc polycup. Insert a stirring rod with a Teflon plate blade at the tip, and
Stirred at 0 rpm. Separately polyvinyl alcohol aa0
5 (Japanese synthetic chemical type.

10 g of an aqueous solution with saponification degree of 88%) was prepared and added to Epicote 828 in 2.5 g portions over 6 minutes.

As a result, Epicoat 828 was emulsified in the polycup to obtain a white emulsion.

Next, 8 g of water containing piperazine or N(2'-aminoethyl)piperazine as a hardening agent was added to this emulsion, and the emulsion was left to harden at 25 DEG C. for 5 days. As the results are shown in Table 1, fine spherical particles were obtained.

In addition, Epicote 82B, piperazine and N(2-7
The Shore A hardness of the equivalent mixture of (minoethyl)piperazine after being left at room temperature for 8 hours was 92 and 80, respectively. Since piperazine is a solid compound at room temperature, it was dissolved in acetone, mixed with Epicote 828, and uniformly mixed with Epicote 828 by deacetation/deacetation under reduced pressure at room temperature.

Example 2 10 g of Epicote 828 used in Example 1 was placed in a 100 country polycup, and while stirring in the same manner as in Example 1, 10 g of an aqueous solution of sodium alginate (manufactured by Hanui Chemicals, grade 300 cps) was added and emulsified. .

Diethylenetriamine dissolved in 8 g of water was added to the obtained emulsion, and the emulsion was left to harden for 6 days at 2.5°C. As shown in Table 2, fine spherical particles were obtained.

Note that the Shore A hardness of an equivalent mixture of Epicoat 828 and diethylenetriamine after being left at room temperature for 8 hours is 85.

Table 2 Example 3 Commercially available phenol/novolac type polyfunctional epoxy resin τ@j5) Epicor) 152 (manufactured by Yuka Shell Epoxy)
10 g was placed in a 100a polycup and emulsified in the same manner as in Example 1. In this case, the protective colloid substance is NL-05 instead of polyvinyl alcohol GL-05.
05 (Japanese synthetic character type.

Completely saponified type) was used.

Piperazine dissolved in 10 g of water was added to the obtained emulsion, and the emulsion was allowed to harden at 25° C. for 5 days. As shown in Table 3, fine spherical particles were obtained.

The Shore A hardness of an equivalent mixture of Epikote 152 and piperazine after being left at room temperature for 8 hours is 94.

Table 3 [Effect of beating] According to the present invention, epoxy-based spherical particles containing no surfactant within the particles could be produced.

Claims (1)

[Claims] A method for producing epoxy spherical particles, which comprises adding a water-soluble amine compound to an emulsion of an epoxy compound emulsified in the presence of a protective colloid and curing the mixture.