JPH0718008A - Production of fine spherical resin particles - Google Patents

Abstract

PURPOSE:To obtain the particles having a high hardness, solvent resistance, and relatively uniform particle sizes by polymerizing a monomer mixture mainly comprising a styrenic monomer and an isocyanurate in an aq. emulsion and then removing coarse particles from the resultant product. CONSTITUTION:A monomer mixture comprising 50-90 pts. wt. styrenic monomer selected from the group consisting of styrene, methylstyrene, and a halogenostyrene, 5-50 pts. wt. isocyanurate having an unsatd. hydrocarbon group, 0-15 pts. wt. (meth)acrylic ester, and 0-5 pts. wt. (meth)acrylic acid is dispersed in an aq. medium and polymerized in emulsion at 40-100 deg.C. Then, coarse particles with particle diameters of 10mum or greater are removed from the resultant product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a fine spherical resin. The fine spherical resin according to the present invention comprises a copolymer of a styrene monomer and isocyanurate having an average particle diameter of 0.05 to 10.0 μm as a basic component, and is a hard and solvent-resistant beautiful comparison. It is a product with uniform grain size, and the form that can be supplied as a product is
The primary particle powder, the secondary particle powder in a form in which they are aggregated, and the emulsified dispersion or emulsion paste in the form in which they are dispersed in an aqueous solution. The products of the present invention include paints, inks,
Adhesives, fillers, spacers, resin molded products, etc., and their applied products are widely used from daily necessities to electrical products, arts and crafts, vehicles, etc., due to their beautiful appearance and good surface properties. Is. Therefore, the industrial application field of the fine spherical resin of the present invention is extremely wide.

[0002]

2. Description of the Related Art Divinylbenzene has hitherto been used as a copolymerization type crosslinking agent in pearl polymerization or emulsion polymerization of styrene, and as a heating type crosslinking agent for vinyl polymer latex, hexa (methoxymethyl) melamine or tetra ( Methoxymethyl) urea is used. Recently, these techniques have been further developed, and studies on the synthesis of uniform-sized microgels have been conducted. (Fukutomi et al., "Polymer", Vol. 41, March issue, pp. 200-203, 1992.
Year)

[0003]

However, in the known method, a fine spherical resin having sufficient properties in terms of hardness, weather resistance, solvent resistance, light resistance, average particle size and photochemical properties is used. It was extremely difficult to synthesize. And when trying to get a good product,
There is a growing tendency to select condensation polymerization type resins rather than polymerization types.

For example, spherical products of phenol resin, urea resin or silicone resin have been produced and put on the market. Here, the inventors of the present invention have continued research for many years on the production of a polymerization type fine spherical resin mainly containing styrene, and the selection of a crosslinking agent for copolymerization is very important for achieving the purpose. It was found that it was a factor. It was confirmed that the physical properties of the product are greatly influenced by the structure of the cross-linking agent, and as a result of intensive efforts to solve this problem, the present invention that should be noted has been completed.

[0005]

The present inventors have selected at least one styrenic monomer selected from the group consisting of styrene, methyl styrene and halogeno styrene.
0 to 90 parts, 5 to 50 parts of isocyanurate having an unsaturated hydrocarbon group, and 0 to 1 of (meth) acrylic acid ester.
When 5 parts and 0 to 5 parts of (meth) acrylic acid are dispersed in an aqueous liquid and emulsion polymerization is carried out at 40 to 100 ° C. to separately remove coarse particles having an average particle size of 10 μm or more,
The inventors have invented that a very large amount of fine spherical resin can be produced very easily.

First, the operation and configuration of the present invention will be described. When a styrene-based monomer and an isocyanurate having an unsaturated hydrocarbon group are dispersed in water and copolymerized,
It is the acid amide atomic group (especially carbonyl group) of isocyanurate that has an affinity for water, and when the raw material mixture is spherically dispersed and emulsified in water, the atomic group is an oil group.
At the water interface, the hydrocarbon group portion or the compound is wrapped inside, and is present in the micelle in a relatively regular orientation. And (meth) acrylic acid ester and (meth) acrylic acid [this also includes (meth) acrylic acid salt and (meth) amide]. Of course, this auxiliary agent may or may not be present, but it is useful to use it in a small amount so as to facilitate the orientation of the isocyanurate and make the average particle diameter of the target substance constant. The present inventors have conducted a number of experiments in order to elucidate the quantitative relationship between these various raw materials, and have now determined this.

Further, the inventors of the present invention, when carrying out the above-mentioned special emulsion polymerization, have problems in the reaction system due to equipment, non-uniformity due to changes in the concentrations or viscosities of various raw materials, and destruction of micelles. I knew that the formation of coarse particles caused by a toe occurred together.

It is natural that the lower the total concentration of the monomer mixture added to the aqueous solution is, the easier it is to control the amount of the coarse particles. However, in order to ensure the method of the present invention, the aqueous solution is required. It is preferable to be performed in the range of 5 to 30%. Of course, maintaining a high concentration of the monomer during the reaction by using a surfactant and a dispersant is a usual means in emulsion polymerization and suspension polymerization, but the present invention does not aim at this.

The term "coarse particles" is a general term for coarse particles, aggregates thereof, or coarse lumps, and in order to achieve the present invention, coarse particles having an average particle size of 10 μm or more are separated and removed after the reaction. There is a need. This fractional removal should be carried out by either a wet method or a dry method by a filtration method, a centrifugal separation method, a classification method, or the like. Reduces resin purity.

That is, according to these rapid methods,
Amorphous (for example, glass shards or mud) powder is mixed in the product of fine spherical resin, and it becomes difficult to make the shape of each particle and its average particle diameter uniform. Such methods should be avoided as much as possible.

The above operations and methods are the basic requirements for constructing the method of the present invention, and must be maintained.

In the present invention, at least one styrenic monomer selected from the group consisting of styrene, methylstyrene and halogenostyrene means styrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, m- Fluorostyrene, p-fluorostyrene, m
-Chlorostyrene, p-chlorostyrene, p-bromostyrene, dimethylstyrene, difluorostyrene and dichlorostyrene alone or as a mixture of two or more, and in some cases divinylbenzene as an impurity,
Even if it contains o-methylstyrene, o-fluorostyrene, o-chlorostyrene, etc. in an amount of several% or less, it is acceptable as an industrial raw material.

The term “isocyanurate having an unsaturated hydrocarbon group” as used in the present invention means trivinyl isocyanurate,
Diallyl isocyanurate, triallyl isocyanurate, diallyl methyl isocyanurate, diallyl ethyl isocyanurate, diallyl propyl isocyanurate, diallyl benzyl isocyanurate, diallyl vinyl benzyl isocyanurate, trimetaallyl isocyanurate, tributenyl isocyanurate, tributadienyl isocyanate At least one compound selected from the group consisting of nurate, tripentenyl isocyanurate, tripentadienyl isocyanurate, tris (vinyloxyalkyl) isocyanurate and bis (diallyl isocyanurate) xylene, that is, the above compounds alone. Alternatively, it is a mixture of two or more kinds. Of course, when the above compound is industrially obtained, a small amount of cyanurate, carbonate, etc., as a secondary component, and a polymerization inhibitor or an antioxidant are contained, but isocyanurate is 50% by weight as a main component. If it is contained in the above, and the polymerization inhibitor does not affect the reaction,
It can be sufficiently used as the raw material of the present invention.

The term "(meth) acrylic acid ester" as used in the present invention means methyl acrylate, ethyl acrylate, propyl acrylate, isoprovir acrylate, allyl acrylate, butyl acrylate, isobutyl acrylate, sec-butyl acrylate, t-butyl acrylate, pentyl. Acrylate, isoamyl acrylate, hexyl acrylate, heptyl acrylate, 2-ethylbutyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate,
A polyol acrylate, a phenyl acrylate, a benzyl acrylate, a phenyl ethyl acrylate, and a methacrylate corresponding to the above-mentioned acrylates, alone or as a mixture of two or more kinds.

The term "(meth) acrylic acid" as used in the present invention means
Acrylic acid, methacrylic acid, sodium acrylate,
Sodium methacrylate, ammonium acrylate,
It is ammonium methacrylic acid, acrylic acid amide, methacrylic acid amide, acrylic acid amine salt, methacrylic acid amine salt or the like alone or as a mixture of two or more kinds.

Now, the above styrene-based monomers 50 to 9 are used.
0 part, isocyanurate having unsaturated hydrocarbon group 5
Dispersing 50 parts, 0 to 15 parts of (meth) acrylic acid ester and 0 to 5 parts of (meth) acrylic acid in an aqueous liquid is carried out in the presence or absence of a suitable interface modifier. That is, if there is a strong emulsifier (or dispersant) only with a mixture of a styrene monomer and isocyanurate, the method of the present invention can be achieved without adding (meth) acrylic acid ester or (meth) acrylic acid. However, if it is desired to use the emulsifier (or dispersant) in a minimum amount, it is convenient to use (meth) acrylic acid ester or (meth) acrylic acid. That is, when the above-mentioned weight part numerical value is 0, it means that these are not used, and even if the maximum amounts are compared, they are smaller than the amounts of the styrene-based monomer and isocyanurate used. You can use it.

Of course, these amounts should not exceed the amount of isocyanurate used. The usage ratio of each of these raw materials was determined through a large number of studies by the present inventors, and it is difficult from the current knowledge of polymer chemistry to make a scientific explanation that can define these. .
Of course, the synthesis and aggregation structure of microgels have been actively researched these days (Fukutomi et al., "Polymer", Vol. 41,
(March issue, pp. 200-203, 1992) No report has been made so far regarding the fine spherical resin containing styrene-based monomer and isocyanurate as main components, which was carried out by the present inventors. . As shown in the present invention, one of the difficulties in the synthesis is the problem of the amount ratio of each raw material, and under the conditions deviating from the conditions of the present invention, it is an object even if the polymerization method and the device are devised. This is because the product could not be obtained.

The above-mentioned raw materials are blended and emulsion polymerization is carried out under high-speed stirring. The rotation speed of the stirrer is often set to 300 to 3000 rpm. Of course, the shape of the stirring blade, the stirring method, the size and shape of the reaction vessel, the reaction temperature, and other factors do not always make the shape and average particle diameter of the spherical granular resin that is the reaction product constant. It was found that a small amount of coarse particles (including coarse lumps and deformed particles are also included in this), so the present inventors have found that the average particle diameter is 10 μm.
It was decided to incorporate into the method of the present invention a process for fractionally removing coarse particles of m or more.

This fractional removal method includes filtration, centrifugation,
The decantation method, the water sieving method or the sieving method may be used, but one of the most convenient methods is to perform the separation operation of the emulsion polymerization liquid by the water squeezing method.In some cases, a Millipore filter paper or a filter cloth is used. It is to pass.

The polymerization mode adopted in the method of the present invention is an emulsion polymerization method. This emulsion polymerization is carried out in the presence or absence of a surfactant. When the amount of the surfactant is small or when the surfactant is absent, it is preferable to use an appropriate dispersant or a water-soluble monomer. As a dispersant,
Polyvinyl alcohol, polyvinylpyrrolidone, poly (meth) acrylamide, poly (meth) acrylic acid (salt), hydroxy (meth) acrylate polymer, ethylene (meth) acrylic acid copolymer (salt), ethylene maleic acid copolymer (salt ), Styrene (meth) acrylic acid copolymer (salt), polyethyleneimine, polyalkylene glycol, polyalkylene oxide, methylolated polyamide, water-soluble melamine resin, water-soluble phenol resin, water-soluble urea resin, casein, gelatin, carboxy Methyl cellulose (salt), carboxymethyl starch (salt), methyl cellulose, hydroxyalkyl cellulose, dextrin, cationized starch, alginic acid (salt), carrageenan, gellan gum, locust bean gum, gum arabic, tiger Ntogamu, glucomannan, The rep mannan, guar gum, alone or as a mixture of two or more such plants mucus is used. Of course, when water-soluble (meth) acrylic acid (salt) is used as the component for the copolymer of the styrene-based monomer of the present invention, the produced copolymer itself (oligomer and polymer) is a self-dispersing agent. Or acts as a self-emulsifying agent.

The surfactant is not particularly limited as long as it does not adversely affect the polymerization reaction, and any of anionic surfactants, cationic surfactants, zwitterionic surfactants or nonionic surfactants can be used. . Since the present invention is usually carried out under high speed stirring, those which cause particularly remarkable foaming such as saponin are not preferable. The main surfactant used in the present invention is sodium alkylbenzene sulfonate, higher alcohol sulfate sodium salt, higher α-olefin sulfonate sodium salt, higher fatty acid salt, higher alkylphenol alkylene oxide sodium sulfonate, higher alkylamine salt, Higher alkyltrimethylammonium salt, higher alkylpyridinium salt, higher acylaminomethylpyridinium salt, higher acyloxymethylpyridinium salt, N, N
-Dipolyoxyethylene-N-higher alkylamine salt,
Higher alkyl polyethylene polyamine salt, trimethyl higher alkyl aniline sulfate, trimethyl higher alkyl benzyl ammonium salt, higher alcohol ethylene oxide adduct, higher alkyl phenol ethylene oxide adduct, higher fatty acid ethylene oxide adduct, higher alkyl amine ethylene oxide adduct, higher fatty acid amide ethylene oxide adduct , Higher fatty acid ester of glycerin, higher fatty acid ester of pentaerythritol, higher fatty acid ester of sorbitol or sorbitan (or ethylene oxide adduct thereof), higher fatty acid ester of sucrose, higher alkyl ether of polyol, higher fatty acid amide of alkanolamine, amphoteric amino acid type The activator, betaine-type amphoteric activator, etc. are used alone or as a mixture of two or more kinds.

The polymerization reaction is carried out in an aqueous solution containing the surfactant or dispersant described above in a small amount (0.05 to 5.00% by weight) in an amount of 50 to 90 parts by weight of the styrenic monomer and the isocyanurate referred to in the present invention. 5 to 50 parts, 0 to 15 parts of (meth) acrylic acid ester and 0 to 5 parts of (meth) acrylic acid are dispersed and carried out in the form of emulsion polymerization under stirring. This emulsion polymerization is preferably carried out in water as it is, with the fine spherical oily substance of the monomer being dispersed in the micelle formed by the surfactant or dispersant. If the micelles are largely destroyed and fluctuated, it becomes difficult to maintain the true spherical state throughout the polymerization process. In general emulsion polymerization, 0
It is carried out at a temperature of up to 150 ° C., but in the method of the present invention, it is necessary to carry out at 40 to 100 ° C., particularly preferably 50 to 90 ° C., in order to maintain the true spherical state. That is, at a temperature lower than 40 ° C, not only the reaction is slow, but also the monomer viscosity or the oligomer viscosity becomes large, and it becomes difficult to form fine spherical oil droplets (this deformation is particularly remarkable in the oligomer state). As described above, it was confirmed from many preliminary experiments that, for example, in emulsion polymerization at 120 ° C. under pressure, the micelles were largely destroyed and changed into an oligomer state, and the Weisenberg phenomenon occurred to produce a large amount of coarse particles. Therefore, in order to achieve the object of the present invention, the reaction must be carried out at a water temperature of 40 to 100 ° C.

Even if the emulsion polymerization is carried out with the above precautions, since some coarse particles are still mixed in the reaction mixture, they are separated and removed as described above. . If the reaction mixture is circulated through the ion exchange resin layer to remove the ionic surfactant, coarse particles are often separated and removed together with the surfactant.

The fine spherical resin produced by the method of the present invention is generally uniform and has a very small particle size distribution, and the spherical shape and the outer surface of the sphere are very beautiful according to electron microscope (SEM) observation. It is a thing. Then, if the particle diameter of the true spherical resin becomes a size that can correspond to the wavelength of light, it will interfere with light and exhibit a rainbow color. Of course, if it deviates from the wavelength of light, or if it coarsens due to secondary aggregation or multi-aggregation during watering, dehydration, or drying, it becomes colorless.

The fine spherical resin referred to in the present invention is usually highly crosslinked, insoluble in water and organic solvents, and excellent in heat resistance and weather resistance. The product of the present invention can be supplied as an emulsion dispersed in water or as an organic solvent dispersion obtained by substituting water with an organic solvent, but if necessary, the solvent is removed, and the product is provided in the form of an anhydrous white powder. You can also do it.

Incidentally, most of the emulsion polymerizations referred to in the present invention are
It is carried out in a radical reaction mode, and a peroxide, an azo compound or the like is used as a polymerization initiator. Further, redox system polymerization may be carried out by sharing a reducing agent with such a radical generator. Further, a combination of radical polymerization and oxidative thermal polymerization may be adopted. That is, while heating the reaction mixture in the presence of the transition metal catalyst, air or oxygen may be contacted, or a peroxide may be added to the reaction system under such an air stream. Peroxides often used in the present invention are ammonium persulfate, potassium persulfate, hydrogen peroxide, benzoyl peroxide, lauroyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, cumene hydroperoxide and the like. Air or oxygen may be blown into the reaction mixture or simply passed through the reaction mixture space. Among the transition metal catalysts, the most commonly used metals are chromium, manganese,
Iron, cobalt, nickel and the like, which are added to the reaction system in the form of either a water-soluble compound or an oil-soluble compound or a combination of both. The technique of carrying out emulsion polymerization using a transition metal catalyst in an oxidizing atmosphere is new.

Whichever emulsion polymerization reaction system is used,
The method of the present invention needs to be carried out at 50 to 100 ° C., and it goes without saying that it may be appropriately used as a pH buffering agent, an antifoaming agent and the like.

[0028]

EXAMPLES The present inventors have conducted a number of experiments on the above-mentioned method of the present invention to clarify the superiority of the present invention. In order to further explain the technical contents of the present invention, the following is given. An example will be given.

Example 1 To a flask equipped with a dropping funnel, a stirrer, a nitrogen introducing tube, a thermometer and a reflux condenser was added 260 g of distilled water, 3 g of a 1% neogen aqueous solution, and 1 g of 28% ammonia water. After stirring while blowing nitrogen gas and adding 0.1 g of the fluorine compound, a monomer mixture prepared beforehand by a dropping funnel (styrene 24.5 g, methyl methacrylate 8.
75 g, triallyl isocyanurate 1.75 g) was added dropwise. Rotate the stirrer to about 1000 rpm,
After stirring for a minute, the temperature was raised, and the catalyst was stirred at 90 to 100 ° C. for 4 hours and 30 minutes by dropping with a quantitative microtube pump. After completion of dropping, the mixture was stirred for 1 hour and 30 minutes. After completion of the reaction, the reaction solution is passed through a strongly acidic cation and weakly basic anion exchange resin to remove ammonia and catalyst, and concentrated under reduced pressure to give a pearly luster with a non-volatile content of 38.8% and a nitrogen content of 0.925%. A crosslinked fine particle dispersion was obtained.

Example 2 As in Example 1, except that p-vinylbenzyl diallyl isocyanurate was used in place of triallyl isocyanurate, and the reaction was carried out at a nonvolatile content of 40.1% and nitrogen content of 0.63%. A crosslinked fine particle water dispersion having a pearly luster was obtained.

Example 3 75 g of styrene monomer, 20 g of triallyl isocyanurate and 5 g of acrylic acid were mixed and added dropwise to 840 ml of distilled water containing 5 ml of 28% ammonia water while vigorously stirring. After completion of dropping, the temperature is gradually raised and stirred at 90 ° C. for 1 hour. Then, 45 ml of a 2.5% ammonium persulfate aqueous solution is added over 2 hours while maintaining the temperature. The system was kept at 90 ° C. for 1 hour, 15 ml of ammonium persulfate solution was added, and the mixture was stirred for 2 hours. After cooling, coarse particles were first removed with a 200-mesh wire mesh, and inorganic salts were removed through a column of strongly acidic ion exchange resin IR-120B and then a column of strong basic ion exchange resin IRA-410. One obtained by concentrating half of the produced aqueous solution under reduced pressure and distilling off 400 ml of water was a stable emulsion showing an interference color, and when observed by SEM, it was a true spherical particle having an average particle size of 0.2 to 0.5 μm. Was observed.

Example 4 22.5 g of styrene monomer, 6.0 g of triallyl isocyanurate, and 1.5 g of acrylic acid were used. Among the remaining 300 g that was not concentrated with the resulting emulsion of Example 1, Similarly, a 2.5% ammonium persulfate aqueous solution 24 m
1 was quantitatively added dropwise over 40 minutes for reaction. The product was the same as in Example 1, and a stable emulsion having a solid content concentration of 11% was obtained, and purification using an ion exchange resin was also performed. Observation of the product by SEM shows that the product is spherical and that the particles are not enlarged in the same manner as in Example 1.

Example 5 9.5 g of styrene monomer, 9.5 g of triallyl isocyanurate and 1.0 g of acrylic acid were added to 360 g of distilled water containing 2 ml of 28% ammonia water, and fluorinated alcohol (HCF ₂ CF ₂ CF) was added. ₂ OH ₂ OH) 0.
5 ml was added and the mixture was stirred at 1000 rpm and kept at 90 ° C. for 1 hour. Then, potassium persulfate 0.
6 g was made into a 20 ml aqueous solution and added dropwise over 2 hours. The monomer odor almost disappeared after 5 hours. The product had a solids concentration of about 5%. When this emulsion was passed through an ion exchange resin column in the same manner as in Example 1,
Particles having a particle size of 10 μm or more were removed, and a stable emulsion was obtained even when water was distilled to a solid concentration of 30% under reduced pressure.

Example 6 28% of 26.6 g of styrene monomer, 11.5 g of trimethallyl isocyanurate, and 4.4 g of methacrylic acid.
340 ml of ion-exchanged water containing 2 ml of ammonia water was mixed, and 0.6 g of potassium persulfate was polymerized with a catalyst prepared by dissolving 20 g of water in 90 ml at 90 ° C. The same treatment as in Example 1 was carried out to obtain a stable emulsion. Obtained. The solid content was 8%.

[0035]

[Effects of the Invention] 50 to 90 parts of at least one styrene monomer selected from the group consisting of styrene, methylstyrene and halogenostyrene, 5 to 50 parts of isocyanurate having an unsaturated hydrocarbon group, and (meth) acrylic acid ester. 0-15 parts and 0-5 parts of (meth) acrylic acid were polymerized in water to obtain a spherical and stable fine particle dispersion.
The fine particles have a relatively narrow particle size distribution and are crosslinked, and are sufficiently stable for a wide range of applications.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location C08F 226/06 MNL

Claims (2)

[Claims] 1. 50 to 90 parts of at least one styrenic monomer selected from the group consisting of styrene, methylstyrene and halogenostyrene, 5 to 50 parts of isocyanurate having an unsaturated hydrocarbon group, and (meth) acrylic acid ester. 0 to 15 parts and (meth) acrylic acid 0 to 5 parts are dispersed in an aqueous liquid, emulsion polymerization is carried out at 40 to 100 ° C., and coarse particles having an average particle diameter of 10 μm or more are fractionally removed. Manufacturing method of fine spherical resin. 2. An isocyanurate having an unsaturated hydrocarbon group is trivinyl isocyanurate, diallyl isocyanurate, triallyl isocyanurate, diallyl methyl isocyanurate, diallyl ethyl isocyanurate, diallyl propyl isocyanurate, diallyl benzyl isocyanurate, diallyl. Vinylbenzyl isocyanurate, trimetaallyl isocyanurate, tributenyl isocyanurate, tributadienyl isocyanurate, tripentenyl isocyanurate, tripentadienyl isocyanurate, tris (vinyloxyalkyl) isocyanurate and bis (diallyl isocyanurate) The method for producing a fine spherical resin according to claim 1, which is at least one compound selected from the group consisting of xylene.