JPS62106921A - Production of fine spherical particle of heat-resistant epoxy resin - Google Patents

Abstract

PURPOSE:To facilitate the formation of fine spherical particles of an epoxy resin improved in heat resistance and solvent resistance, by treating said particles cured with an amine curing agent with a polybasic acid. CONSTITUTION:Fine spherical particles of an epoxy resin, average particle diameter of 0.1-100mu, cured with an amine curing agent are treated with a polybasic acid. As processes for preparing said particles, (1) a process in which an uncured epoxy compound is cured after it is dispersed in an aqueous liquid and (2) a process in which an uncured epoxy compound and an amine curing agent are polymerized by static precipitation polymerization in a liquid polyol are particularly preferable from the viewpoint of the uniformity, sphericity, etc., of the particles. Above all, the process (1), especially, that in which an emulsion made by using a surfactant, etc., is used is preferable in respect of the rate of production. As the polybasic acids, mineral acids and compounds having carboxyl groups or sulfonic groups directly bonded to a benzene ring are used desirably.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing epoxy spherical fine particles having an average particle diameter of 0.1 to 1000 μm and having excellent heat resistance and solvent resistance.

The particles of the present invention can be used as a compounding agent for cosmetics, molding resins, etc., as a coating compounding agent for paper, films, non-woven fabrics, etc., and as a compounding agent for inks, paints, adhesives, etc. to improve flow characteristics, Used for purposes such as preventing blocking, improving friction properties, coloring, UV absorption, and reinforcement.

[Prior art] In Japanese Patent Publication No. 53-42360, a mixture of an epoxy compound and a curing agent is cured in water to form spherical particles in 1q.
A technology has been disclosed. Also, JP-A-53-73249
The publication discloses a technique for obtaining a fine powder from a mixture of an epoxy resin, a surfactant, a curing agent, and water.

Also, JP-A-59-170114. In the publication, the present inventor has already proposed a technique for obtaining spherical fine particles by adding a piperazine curing agent to an emulsion of an uncured epoxy compound.

In order to improve the heat resistance properties of these spherical epoxy particles, there is generally a method of at least partially using an epoxy compound having three or more epoxy groups in the molecule or a curing agent having three or more active hydrogens in the molecule. There is.

However, there are cases in which it is not possible to use them due to manufacturing technology, and the heat resistance and solvent resistance of the product are sometimes inferior.

[Problems to be Solved by the Invention] An object of the present invention is to provide a technique for further improving the heat resistance and solvent resistance properties of epoxy spherical fine particles cured with an amine curing agent by simple means. do.

[Means for solving problems] In order to achieve the above object, the present invention consists of the following configuration.

(1) The average particle diameter cured with an amine curing agent is 0.
．． A method for producing heat-resistant epoxy spherical fine particles, which comprises treating epoxy spherical fine particles with a size of 1 to 1000 μm with a polybasic acid.

The details of the present invention will be sequentially explained below.

The epoxy spherical fine particles having an average particle diameter of 0.1 to 1000 μm, which constitute the present invention, are generally prepared as follows.

Mechanically pulverized particles of an uncured epoxy compound that is solid at around room temperature, or an epoxy compound that has been partially or fully cured with an amine-based curing agent, are spheroidized by a method such as gravity falling through a heating cylinder, and then spheroidized with an amine-based curing agent. There is a method of completing curing by contacting with a system curing agent (referred to as the first method).

Another method is to suspend an uncured epoxy compound in water (the main liquid) and then cure it (this is the second method).

Another method is a method in which an uncured epoxy compound and an amine curing agent are subjected to static precipitation polymerization in a liquid polyol (referred to as the third method).

In the present invention, the above-mentioned first to third methods are not particularly limited, but the second method and the third method are particularly preferable in terms of particle uniformity, nacreousness, etc. Among these, the second method, particularly the method using an emulsion using a surfactant, is preferred from the viewpoint of productivity.

The epoxy compound used in the present invention preferably contains two or more epoxy groups in the molecule.

Examples include glycidyl etherified bisphenol A-type compounds at both ends, diglycidyl ethers of polyethylene glycol, polyglycidyl ethers of phenol novolac-type compounds, and N,N,N',No-tetraglycidyl m-xylene diamine. , used alone or in combination. Furthermore, if necessary, it is possible to add a small amount of a compound having one epoxy group in the molecule, such as glycidyl methacrylate. Furthermore, a modified epoxy compound in which a part of the epoxy group is bonded to a compound having an amino group or the like can also be used in the present invention.

In the first method, one of the above-mentioned epoxy compounds that is solid at around room temperature is mechanically pulverized, or the epoxy compound that is solid at around room temperature is partially or completely cured with an amine-based curing agent such as piperazine or metaxylylene diamine. Powder particles are first prepared by mechanically crushing the resinous material. Subsequently, these particles are charged from the top of a heating cylinder whose internal temperature is approximately 60 to 400°C, and spheroidized by a method such as gravity falling. After spheroidization, the particles are immersed in an aqueous solution containing an amine curing agent such as biperazine ethylene diamine or metaxylylene diamine, or in a solvent solution such as dioxane, or mixed directly with a curing agent, and processed as needed. By heating roughly, the amine curing agent is introduced into the particles and cured.

In these curing reactions, curing agents other than amine curing agents such as phthalic anhydride may coexist.

In a second method, particles of an epoxy compound suspended in an aqueous liquid are cured with an amine-based curing agent. In this method, the curing agent and curing method are not particularly limited, but (1) a method in which an epoxy compound to which a curing agent has been added in advance is suspended in an aqueous liquid and cured as it is; (2)
There is a method of curing by adding a water-soluble amine curing agent to an aqueous suspension of an epoxy compound.

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

Approximately 0.2 to 1.2 equivalents of these curing agents are added to the epoxy compound to form an aqueous suspension.

Examples of the method of curing an aqueous suspension of an epoxy compound by adding a water-soluble amine curing agent to it (the latter method) include the following.

(A> When adding a water-soluble curing agent to an emulsion of an epoxy compound and curing it into fine particles, piperazine or a piperazine derivative generally shown below is stoichiometrically calculated from the epoxy equivalent of the emulsion of an epoxy compound. A method using a water-soluble curing agent containing 0.15 equivalents or more.

(R, R' are hydrogen atoms or hydrocarbon residues having 1 to 4 carbon atoms) (B) When adding a water-soluble curing agent to an emulsion of an epoxy compound and curing it into fine particles, hydrazine or A method using a water-soluble curing agent containing 0.2 equivalents or more of a hydrazine derivative stoichiometrically calculated from the epoxy equivalent of an emulsion of an epoxy compound.

(R represents hydrogen, an alkyl group having 5 or less carbon atoms, a phenyl group, or a 2-hydroxyethyl group).

(C) A water-soluble curing agent is added to the emulsion of the epoxy compound and the mixture is hardened into particles with an average particle size of 0.5 to 50.
When manufacturing μm spherical epoxy particles, (I) the emulsion of the epoxy compound is prepared by adding 10% by weight or more of a surfactant of H1812 or higher to the epoxy compound, and (II) a water-soluble curing agent. is an amine compound whose Shore A hardness of the mixture obtained by mixing an equivalent amount with the above epoxy compound at room temperature and leaving it for 8 hours is 70 or more, and this amine compound is added in an amount of 0.5 equivalent or more to the epoxy compound. How to add.

In order to achieve the present invention, any of the above-mentioned methods may be used, and although there are no particular limitations, the above-mentioned (A),
Particularly preferred are those of (B) and (C).

The following compounds are generally mentioned as the amine curing agent used in the second method, but are not particularly limited thereto. These include piperazine, hydrazine, polyethylene polyamines such as ethylenediamine, diethylenetriamine, and triethylenetetramine, alcohol amines such as monoethanolamine, and N(2-aminoethyl)piperazine.

In the second method, an aqueous suspension of the epoxy compound is prepared, and an example of this method is given below.

(1) A method in which an epoxy compound or its solution is continuously discharged from a nozzle that moves in the air or in a liquid, cutting it into droplets and collecting the droplets in the liquid.

(2) A method in which an epoxy compound or its solution is ejected in pulses from a nozzle in the air or in a liquid, and then collected in the liquid.

(3) A method of emulsifying using a combination of an epoxy compound containing a surfactant and water.

(4) A method of emulsifying using a combination of a powder emulsifier, an epoxy compound, and water.

(5) A method of emulsifying using a combination of water containing a protective colloidal substance and an epoxy compound.

Among the above methods, methods (3) to (5) are preferably used in the present invention from the viewpoint of productivity, but a combination of methods (1) to (5) is also preferably used in the present invention.

The surfactant is not particularly limited in the methods (A> and (B)) for obtaining epoxy spherical particles, and may be a surfactant that is generally known as an emulsifier for uncured epoxy resins such as polyoxyethylene phenol-substituted ethers. If the HIB value does not satisfy this range, it can be used without any problem.As a surfactant used in the above method (C), a surfactant with an HLB f value of 12 or more is used in an amount of 10% or more based on the epoxy compound.If the HIB value does not satisfy this range, tends not to be cured into particles even when using the specific amine curing agent mentioned above.

・Generally, the types of surfactants preferably used in the second method include ether-type nonionic surfactants such as polyoxynyletine/phenol-substituted ether type and polyoxyethylene/polyoxypropylene block/polyether type;
There are ester-type nonionic surfactants such as high-strength fatty acid esters of polyethylene glycol and fatty acid esters of polyhydric alcohols.

When using a powder emulsifier such as crystalline fresh cellulose or barium chloride, this method is suitable for producing relatively large particles with an average particle diameter of 10 to 1000 μm.

It is also possible in the present invention to emulsify with a substance exhibiting a protective colloid action, such as polyvinyl alcohol, hydroxymethylcellulose, or sodium alginate, instead of a surfactant.

When emulsifying an epoxy compound using a surfactant, powder emulsifier, or protective colloid, use an epoxy compound containing them or water and gradually add water to the epoxy compound being stirred at high speed. is common. The concentration of the produced emulsion is usually 10 to 80% by weight.

The general method for adding an amine curing agent to a suspension of an epoxy compound is to add the curing agent directly or in the form of an aqueous solution. The curing agent may be a mixed system with other amine-based curing agents or different types of curing agents, but it is preferable that the curing agent satisfies the specific usage conditions of the specific curing agent mentioned above.

In the second method, (1) if the curing agent is added to the epoxy compound in advance and then made into an aqueous suspension, then (2) if the curing agent is added after the epoxy compound is made into an aqueous suspension; The curing agent additive causes a curing reaction when it is left standing or is gently stirred. When you want to obtain a sufficient hardening condition,
There is a way to heat the whole thing.

The third method is to dissolve an epoxy compound having 2 to 7 epoxy groups and an amine curing agent in a polyester polyol or polyalkylene polyether polyol, and leave it standing!
i Polymerize.

In the first and second methods, additives such as pigments may be added to the epoxy compound as a raw material if necessary, and ketones or other diluents for the epoxy compound may be used to lower the viscosity. It is no use even if it contains such things.

The epoxy-based spherical fine particles used in the present invention can be prepared by the method described above, but those used in the present invention have an average particle diameter of 0.1 to 1000 μm, preferably 0.5 to 500 μm.
They are micrometer particles. When the average particle diameter is less than 0.1 μm, it becomes difficult to collect the particles, and when it exceeds 1000 μm, it becomes unsuitable for use as a compounding agent in cosmetics, paints, etc. due to the feeling of foreign bodies and sedimentation.

Next, the polybasic Ill principle for achieving the present invention will be explained.

The polybasic acids used in the present invention include mineral acids such as sulfuric acid, phosphoric acid, and boric acid, and chain hydrocarbon polycarboxylic acids such as oxalic acid, maleic acid, itaconic acid, citric acid, and tributenecarphonic acid. i! Class 2, phthalic acid, trimellitic acid,
Examples include aromatic polycarboxylic acids such as pyromellitic acid, aliphatic and aromatic polysulfonic acid compounds, and compounds having one or more carboxylic acids and one or more sulfonic acids. Among them, compounds having a mineral acid and a carboxyl group or sulfone group directly bonded to a benzene ring are preferably used in the present invention.

The polybasic acid used in the present invention does not necessarily have to be in a free acid form, and can also be used in the form of a water-soluble salt such as a sodium salt or an ammonium salt.

A typical method for treating the above-mentioned epoxy-based spherical fine particles with the above-mentioned polybasic acid will be described below.

Generally, it is preferable that the epoxy spherical fine particles used in the treatment are dispersed in water or an organic solvent. The most preferred method is an aqueous liquid; in this case, it is possible to use a wide range of treatment conditions, such as using a wide variety of polybasic acids.

The polybasic acid used in the treatment is either directly dissolved in the dispersion of epoxy spherical particles, or a previously dissolved polybasic acid is added to the dispersion. It is preferable to stir during processing.
More favorable treatment effects can often be obtained by heat treatment than at room temperature.

As for the heat treatment conditions, generally a high temperature tends to give favorable results, and usually the temperature is 40° below the boiling point of the dispersion medium used.
It is preferable to use a temperature condition ranging from a low temperature to the boiling point. Although the treatment time is not particularly limited, it is usually preferable to carry out the treatment for 30 minutes or more.

In the case of polybasic acids that are soluble in organic solvents such as alcohols, such as some mineral acids, carboxylic acids, and sulfonic acid compounds, treatment in organic solvents is also possible, but this method is particularly suitable for dissolving them in aqueous liquids. This method is effective when using polybasic acids that do not

Even if a polybasic acid is difficult to dissolve in an aqueous liquid in its free acid form, the solubility improves when it is made into a salt form, such as an alkali metal salt. use In this case, it is often difficult to obtain a sufficient treatment effect with simple heating and stirring, so in addition to polybasic acid salts, compounds with stronger acidity such as hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, etc. together with
Good results are often obtained when heat treatment is performed under conditions of approximately pH 6 or lower.

The present invention tends to be efficiently achieved when the polybasic acid is used in an amount of 0.2 or more, preferably 0.3 or more per amino group contained in the epoxy spherical fine particles. When the amount of polybasic acid used is less than this, it is generally seen that the heat resistance and solvent resistance of the particles tend to be difficult to improve.

The amino groups contained in the epoxy spherical particles include all primary, secondary, tertiary, and quaternary amino groups, and the main part is the polymer main chain that is the reaction product of the epoxy group and the amine curing agent. Or it exists on the side chain as a constituent component. Their particulate abundance can be estimated from the amount of the amine curing agent used. However, in the second and third methods for producing epoxy-based spherical particles, not all of the amine-based curing agent used reacts with the epoxy group, so in this case, the remaining liquid after removing the particles The amount of the amine curing agent contained can be determined by a method such as titration, and the amount subtracted from the amount used can be determined as the amount in the particles.

In the present invention, when treating epoxy-based spherical particles with a polybasic acid, compounds having anionic groups such as sulfonic groups and carboxyl groups, such as acid dyes and some ultraviolet absorbers, are allowed to coexist. It is also possible to adsorb ions onto the particles.

The treated dispersion can be recovered as a powder of epoxy spherical particles by neutralizing the dispersion with an alkali, if necessary, filtering, washing and drying.

[Example] Example 1 A commercially available bisphenol A tricidyl ether type epoxy resin (Epicote 828, made by Yuka Shell Epoxy >10CJ) was placed in a 100cc polycup, and H
0.8 CI of Neugen EA-137 (manufactured by Dai-Kogyo Seiyaku), a commercially available polyoxyethylene/phenol-substituted ether surfactant of LB13, was added. The mixture was kneaded for 1 minute at 80 rpm using a stirring rod equipped with a Teflon plate blade at the tip. Subsequently, 5 cc of water in a syringe was added in 1.5 cc portions at 1 minute intervals while stirring at ao-o-rpm.

A milky white emulsion was obtained in the polycup.

To this uncured epoxy emulsion was added a hardening solution prepared by dissolving 0.6 g of piperazine in 8 cc of water, and the mixture was homogenized by gentle stirring.

This liquid was allowed to stand at 25°C for 5 days to harden into spherical particles with an average particle diameter of about 6 μm.

The hardened particles were suctioned using filter paper; they were separated by filtration, and after washing, the particles were redispersed in water to obtain 1 q of a dispersion containing 10% by weight of particles.

When the amount of piperazine remaining in the filtrate was determined by titration with 0.1N hydrochloric acid using methyl orange as an indicator, it was found that 85% by weight of the piperazine used (piperazine reaction rate) reacted with the epoxy group and was incorporated into the particles as a constituent component. It was found that

The above dispersion was treated with various polybasic acids corresponding to 2 equivalents of the amount of amine groups in the particles. The glass transition temperature (Tg) of the treated particles dried at 50°C was measured using Perkin-Elmer DS.
Table 1 shows the results measured using C-20.

Table 1 Example 2 10 g of a commercially available phenol novolac type epoxy resin (Epicoat 152, manufactured by Yuka Shell Epoxy) was mixed at 100C.
Add the surfactant Neugen EA to the polycup of C.
0.8g of -137 was added.

Emulsification was performed in the same manner as in Example 1, followed by 8CC
1 equivalent of piperazine dissolved in water was added, and 6
The mixture was allowed to stand for a day and was cured to obtain spherical fine particles with an average particle diameter of 6 μm.

The hardened particles were filtered, washed, and then redispersed in 190 q of water.

The piperazine reaction rate determined from the amount of piperazine remaining in the filtrate was 58%.

The above dispersion was heated at 98° with sulfuric acid equivalent to the amount of amino groups in the particles.
Treated for 11 hours. The treated dispersion was neutralized to pH 6.5 with a 1N aqueous sodium hydroxide solution. Table 2 shows the Tg of the particles dried at 50°C and the Soxhlet extraction rate (5 hours) at the boiling point of ethanol.

Table 2 [Effects of the Invention] According to the present invention, it has become possible to easily produce epoxy-based spherical fine particles having an average particle diameter of 0.1 to 1000 μm and having excellent heat resistance and solvent resistance properties.

As a result, cosmetics, plastics, coatings,
We are now able to provide excellent compounding agents for inks, adhesives, paints, etc.

Claims (4)

[Claims] (1) Average particle diameter cured with amine curing agent is 0.1
A method for producing heat-resistant epoxy-based spherical fine particles, which comprises treating epoxy-based spherical fine particles of ~1000 μm with a polybasic acid. (2) A method for producing heat-resistant epoxy spherical fine particles according to claim (1), which comprises adding a polybasic acid to epoxy spherical fine particles suspended in an aqueous liquid and heat-treating the mixture. (3) The method for producing heat-resistant epoxy spherical fine particles according to claim (1), wherein the polybasic acid is selected from mineral acids and aromatic polybasic acids. (4) Claim (1) characterized in that the epoxy spherical fine particles are obtained by curing fine particles of an epoxy compound suspended in an aqueous liquid with a water-soluble amine curing agent. The method for producing the heat-resistant epoxy spherical fine particles described above.