JPS5865703A - Production of polymer particle - Google Patents

Abstract

PURPOSE:To facilitate the production of filled vinyl polymer particles having a uniform and small particle diameter, by mixing a filler pretreated to impart oleophilicity to its surfaces with a vinyl monomer and suspension-polymerizing the mixture in water. CONSTITUTION:A filler such as iron oxide or calcium carbonate is dispersed in water, and an aliphatic-based surfactant is added to form a bimolecular adsorption layer of surfactant on the surface of the filler. Then, by washing the filler with an acidic solution, a monomolecular layer is formed. In this way, in order to prevent agglomeration in an oily vinyl monomer, the surfaces of the filler are rendered oleophilic. The purpose filled polymer particles are prepared by mixing an oleophilicity-imparted filler with an oily vinyl monomer such as styrene or methyl acrylate and suspension-polymerizing the mixture in water in the presence of an initiator (e.g., benzoyl peroxide) and a suspension-protecting agent (e.g., polyvinyl alcohol).

Description

[Detailed description of the invention] The present invention relates to a method for producing polymer particles.

Polymer particles containing fillers are electrophotographic.

Such as paints, inks, ion exchange resins, resin products, biological carriers, immobilized enzyme carriers, immunoserological diagnostic drug carriers, and pharmaceutical administration carriers.

Used in many fields.

Traditionally, filler-containing polymer particles are produced by mixing fillers with polymers produced by conventional polymerization methods. For example, a filler is mixed into a solution of a polymer in an organic solvent, the solution is thoroughly stirred to make it homogeneous, and then spray-dried, or a polymer solution is mechanically dispersed in water containing a filler, and then an organic There is a method of recovering the solvent or a method of mixing the polymer and filler and then pulverizing them. These methods require equipment to remove the solvent, energy to remove the solvent, and the dispersion state of the filler in the polymer particles is not uniform, resulting in irregular morphology and particle size of the polymer particles. It has disadvantages such as:

To avoid these drawbacks, it has been proposed to add fillers to the monomers and prepare polymers by suspension polymerization.
However, the surface of ordinary fillers is often hydrophilic;
In the case of water-soluble monomers, the filler is well dispersed in the monomer, but in oil-based monomers, the filler is dispersed uniformly and separated. phase, so that polymer particles with satisfactory filler content cannot be obtained. For this reason,
A method for producing polymer particles containing a filler is to prepare a high viscosity monomer solution in which a polymer is dissolved in a monomer, add a filler to this monomer solution, and carry out suspension polymerization. It is known (Japanese Unexamined Patent Publication No. I8!16-65406).

However, in the filler-containing polymer particles obtained by this method, the dispersibility of the filler is poor and the distribution of the filler in the polymer particles is non-uniform.

Furthermore, in this method, it is difficult to obtain single integrated particles containing a filler with a small particle size due to the high viscosity of the monomer solution;
Obtained as polymer particles with a particle size of 0 μm or more, and
In many cases, the particle size is also non-uniform.

As a result of intensive research on the method for producing polymer particles containing fillers, the present inventors found that the various problems mentioned above were solved by carrying out suspension polymerization using a filler treated to impart oil-producing properties to the surface. The present invention has been accomplished by discovering that polymer particles containing fillers can be obtained.

That is, an object of the present invention is to provide a method for producing polymer particles containing fillers.

In carrying out suspension polymerization of a vinyl monomer containing a filler in water in the presence of a polymerization initiator and a suspension preservative according to the present invention, the filler is treated to impart lipophilicity to the surface. It is characterized by using a filler that does not aggregate in the oil-based vinyl monomer.

A method for producing vinyl polymer particles containing fillers is provided.

Next, the present invention will be explained in detail.

Oil-based vinyl monomers used in the present invention include aromatic vinyl compounds such as styrene, α-methylstyrene, ethylstyrene, vinyltoluene, and chlorostyrene; Unsaturated carboxylic acid ester compound, methacryloethryl,
Examples include α,β-unsaturated nitrile compounds such as acrylonitrile and halogenated vinyl compounds such as vinyl chloride and vinyl bromide.

It is also possible to mix and copolymerize divinylbenzene, vinyl methacrylate, and polyfunctional monomers such as acrylic acid polyesters or methacrylic polyesters of polyols such as ethylene glycol or polyethylene glycol. The preferred mixing amount is less than 10 lbs. Also acrylic acid and methacrylic acid.

Water-soluble monomers such as itaconic acid, acrylic acid, and methacrylic acid amide may be mixed and copolymerized to the extent that they do not inhibit suspension polymerization, and conjugated diene compounds such as butadiene, isoprene, piperylene, etc. can be obtained. The polymer particles containing the agent may be mixed and copolymerized to the extent that they do not aggregate or stick to each other.

The filler used in the present invention is treated to impart lipophilicity to the surface, for example, metals such as iron, cobalt, nickel, copper, and aluminum, and lanthanum series such as lanthanum and gadolinium. Alloys with other metals such as oxidation, iron oxide, cobalt oxide, lead oxide, aluminum oxide, zinc oxide.

Silicon oxide, 1! Metal oxides such as titanium chloride, magnesium carbonate, calcium carbonate, silicon range aluminum, barium sulfate, lead carbonate, zinc sulfide, cadmium sulfide, and
Metal salts such as lead aluminate, cobalt aluminate, and 1st water pot chloride.

Nickel Meta 2 Is Doazo Yellow Lutz Drake R, Permanent Red, 2B, 2G.

Pigments such as copper phthalocyanine blue and copper 7 thalocyanine green, or fillers such as metal chelate compounds.

The surface of these fillers before treatment is hydrophilic;
Up to d1, fillers often aggregate together in the oil-based vinyl monomer, making it difficult to uniformly disperse them in the oil-based vinyl monomer.

In the present invention, the filler is uniformly dispersed in the oil-based vinyl monomer and left for a long time. The filled filler is then used. The particle size of the filler needs to be smaller than the target polymer particles containing the filler, and is preferably about 30~5000~.
7. Any method may be used to impart lipophilicity to the surface of the filler, but 1.
The particles are washed with an acidic solution containing excess fatty acids as the main component in a medium such as pH 7, preferably at temperatures above 7°C and below 7°C to form a monomolecular layer on the surface of the filler. One example is a method of poisoning the plant (Japanese Unexamined Patent Publication No. 51-22688). In this case, examples of surfactants that produce fatty acids include alkali metal salts of unsaturated fatty acids such as rosin acid, dodecenoic acid, tetradecenoic acid, and hexadecenic acid.

Examples include alkali metal salts of saturated fatty acids such as listic acid, pallic acid, stearic acid, and laginic acid, and alkaline earth metal salts of rosin acid.

Examples of acidic solutions with a pH of less than 7 include lower alcohols such as methanol and ethanol, lower ketones such as aton and methyl ethyl ketone, and solutions prepared by adjusting water with mineral acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid. .

The degree of treatment to form a layer of two molecules of a surfactant containing fatty acids as a main component on the surface of the filler is usually 30 to 160°C.
, preferably 70 to 110, and the processing time is usually α
I) ~2 hours, preferably ah~1 hour. In addition, the degree of surfactant containing fatty acids as a main component in the dispersion medium is not particularly limited, but is usually 1-2 weight or more,
Preferably the amount is 1 to 20.

Fillers treated by this method form a monomolecular layer of fatty acids on the surface as described above, and the hydrophilic groups of the fatty acids are adsorbed onto the filler surface, with the lipophilic groups facing outward. It is thought that lipophilicity is imparted to the surface of

Another treatment method for imparting lipophilicity to a filler is to bring into contact with the filler a compound that has a part with extremely high affinity for the filler and a lipophilic part in its molecule. One example is a method in which the filler is treated so that the lipophilic portions are bound to the filler by adsorption or chemical bonding, and the lipophilic portions are aligned outward. Examples of such compounds include silane coupling agents such as trialcoxin diamine compounds as shown in formula (I) below.

(RO)s 81 M-...(I) (R is an alkyl group having 1 to 3 carbon atoms, R' is an alkyl group, alkenyl group, or allyl group with or without a substituent; .

For example, -(C1%+)s NHm, -(eHs)m
8B.

(CHm)m NHC*Hs, -(CHs)sNl
l-(CHs)mNHs-CHmCHs, -(CH
s)m0-C-C(CHs)=CHs, 1) Furthermore, titanium coupling agents such as alkoxytitanium compounds as shown in the following formula (6) can be mentioned.

(R') BIT s R'4-II ・== (If
) (i is an alkoxy group or a carboxy group with or without a substituent, such as CH, -0/, etc., and ar is an alkylcarboxy group, a substituted benzenesulfoxy group, a substituted phenoxy group, an unsubstituted (Saturated carboxy group, 0 0, etc., m is 1..2t?, : is 3.) As a method for bonding a silane coupling agent or a titanium coupling agent with a filler, for example, using a filler and a silane coupling agent or a titanium coupling agent in an inorganic medium such as water or an organic medium such as alcohol, ether, ketone, ester, etc., heated while stirring, and after heating, the filler is decanted with a decantation cylinder or the like. Examples include a method of separating and removing an inorganic medium or an organic medium by drying under reduced pressure or the like.

Alternatively, the silane coupling agent or titanium coupling agent can be bonded to the filler by directly mixing the filler and the silane coupling agent or titanium coupling agent without using an inorganic or organic medium and heating the mixture. good.

The heating temperature in these methods is usually 30 to 100°C, and the heating time is about 30 minutes to 2 hours. The amount of silane coupling agent or titanium coupling agent to be used for the filler is determined appropriately depending on the surface area of the filler, but is usually 1 to 60 parts by weight, preferably 2 to 30 parts by weight, per 100 parts by weight of the filler. Department.

When an inorganic medium or an organic medium is used, the concentration of the silane coupling agent or titanium coupling agent in the medium is not particularly limited, but is usually 1 weight or more of #k.
It is f.

Yet another method for imparting lipophilic properties to fillers is to process the fillers in a hydrophobic medium containing compounds with surfactant effects such as fatty acids, alkyl sulfur I11 alkylaryl sulfonic acids, etc. using a crusher machine such as a ball mill. A method in which an aqueous dispersion of fine filler powder produced by a wet method is added to a hydrophobic medium containing the surfactant and emulsified. A method of imparting lipophilicity to the filler by distilling off water by post-heating, or an aqueous dispersion of fine filler powder produced by a wet method etc. by preheating the hydrophobic medium containing the surfactant. There is a method of imparting lipophilicity to the filler by adding and mixing and simultaneously distilling off water.

There are various methods for separating the lipophilic filler obtained by these methods from the hydrophobic medium. Fillers can be precipitated by mixing alcohol with a hydrophobic medium containing lipophilic fillers! ! The filler can be collected, such as by filtration or decanting.

Fillers treated to impart lipophilic properties by these methods are extremely easily and stably dispersed in oil-based vinyl monomers, and cannot undergo solid-liquid separation such as precipitation or aggregation by gravity, magnetic force, centrifugal force, etc. It doesn't happen. Fillers treated to impart lipophilic properties are preferably present in the vinyl monomer.
-50% by weight Lfb, particularly preferably 5-30% by weight.

The filler-containing polymer particles of the present invention are prepared by suspending a mixture of the above-mentioned oil-based vinyl monomer and a filler treated to impart lipophilicity in an aqueous phase in the presence of a polymerization initiator and a suspension preservative. It is produced by turbid polymerization, and a chain transfer agent is used if necessary. The polymerization initiator is selected from organic solvent soluble polymerization initiators commonly used in the radical polymerization of vinyl monomers. For example, benzoyl peroxide, acyloyl peroxide such as lauyl peroxide, and cumene hydroperoxide.

Aralkyl hydroperoxides such as paramenthane hydroperoxide, t-butyl perbenzoate,
Examples include alkyl peracid esters such as 1-propyl peracetate, dialkyl peroxides such as di-1-butyl peroxide, and azobisacylonitrile such as azobisisobutyronitrile and azobiscyclohexanecarbonitrile. These polymerization initiators are generally used in an amount of 01 to 5 parts by weight, preferably 05 to 3 parts by weight, per 100 parts by weight of the vinyl monomer. As a chain transfer agent.

For example, straight-chain or branched alkyl mercaptans, halogenated hydrocarbons, etc. may be mentioned.1 Usually, if necessary, up to 5 parts by weight of vinyl monomers are added.

The #1 turbidity protectant is used to protect the suspended state of the vinyl monomer in the aqueous phase. Examples of organic suspending agents include polyvinyl alcohol and polyvinylpyrrolidone.

Hydrophilic synthetic polymer substances such as polyethylene glycol,
Natural hydrophilic polymeric substances such as gelatin and water-soluble starch, hydrophilic semi-synthetic polymeric substances such as carboxymethylcellulose, etc. can be mentioned, and inorganic suspension protectants include, for example, magnesium, barium or calcium. Examples include phosphates, calcium carbonate, magnesium carbonate, zinc white, aluminum chloride, and aluminum hydroxide. Furthermore, these suspension protectants can be used in combination with nonionic, anionic, or cationic surfactants. These suspension protectants are usually used in an amount of 0.05 to 30 parts by weight per 100 parts by weight of the vinyl monomer, and when a surfactant is used in combination, an additional amount of 2 parts by weight or less is used per 100 parts by weight of the vinyl monomer. .

The suspension polymerization method is not particularly limited, but for example, a filler treated to impart lipophilicity to the surface of the vinyl monomer 1 cooled to a temperature at which polymerization does not start, a polymerization initiator, and as necessary. An organic phase consisting of a chain transfer agent used in the process and an aqueous phase consisting of water, a suspending protectant and a surfactant used as necessary are mixed and stirred at a temperature below the polymerization initiation temperature,
An example of this method is to suspend the organic phase in the form of fine droplets of uniform particle size in the aqueous phase, and then raise the temperature of the suspended system while stirring to initiate polymerization of the vinyl monomer. The particle size and particle size distribution of the filler-containing polymer particles obtained by this method depend on the stirring conditions before the start of polymerization, the type S of the suspension protectant and surfactant used as necessary, and the amount thereof. By appropriately combining them, it is possible to obtain filler-containing polymer particles having the desired particle size and particle size distribution.

The amount of the aqueous phase to be used relative to the organic phase is not particularly limited, but it is usually 100 to 200 parts by weight per 10 g of the organic phase.
0 parts by weight, preferably 200 to 1000 parts by weight. Stirring to suspend the organic phase as fine droplets in the aqueous phase is usually 300 to 20,000 r, p, m,
Preferably 5 minutes at 100 tons and 20,000 r-p, m
Stir for 30 minutes, preferably 10-25 minutes. The polymerization temperature when the vinyl monomer is polymerized by raising the temperature of the suspension system can be determined as appropriate depending on the vinyl monomer to be polymerized, the type and amount of the polymerization initiator used, but it is usually 50- 15
0°C, preferably 60-100°C.

After completion of polymerization, the filler-containing polymer particles can be separated by an operation such as centrifugation, and the separated polymer particles are washed with water, ethanol, acetic acid 1-2, etc. as necessary. Ru.

According to the production method of the present invention, the average particle size can be easily reduced to αl-5.
Polymer particles containing fillers with a very narrow particle size distribution of 0/Am can be obtained.

The preferred average particle size of the filler-containing polymer particles obtained according to the present invention is 01 to 80 μm, and an average particle size of this range is the easiest to use.

It is extremely useful because its properties can be utilized.

For example, when a colored filler is used, the filler is uniformly dispersed in the polymer particles, so when the polymer particles are molded, a product with no color unevenness can be obtained, which makes it possible to produce plastic products. Difficulties in the coloring process can be solved all at once. In addition, when extremely dense fillers are used, high-density polymer particles can be obtained, and one polymer particle can be easily separated from a liquid medium by gravity, centripetal force, etc. Become. It also has the advantage that uniform high-density molded products can be easily produced. Furthermore, when a magnetic filler is used, it becomes possible to move the polymer particles within a liquid medium, an organism, or a container by magnetic force. Further, polymer particles containing the filler of the present invention having a small particle size have an extremely large surface area per unit volume, and are therefore suitable as a carrier that utilizes the surface of one polymer particle.

As described above, the filler-containing polymer particles obtained by the present invention can be provided with various chemical or physical properties by combining the types of polymer and the type of filler, and are extremely useful. It is a polymer particle.

The present invention will be explained in more detail with reference to Examples below.

Example 1 Fa@ with an average particle diameter of 100A0 prepared by a wet method
2 of potassium oleate to 1 ton of water containing 04100 f.
Add 400% of the aqueous solution by weight and stir at 90°C for 30 minutes. After cooling, adjust the mixture to -6 using dilute hydrochloric acid.
FazQ4 particles aggregate, so V
Washed twice with 0- and twice with 30OssgK''C of ethanol and dried under reduced pressure.

1 G of polyvinyl alcohol aqueous solution was placed in a 4-day flask equipped with a stirrer, reflux condenser, dropping tube, and temperature needle.
, add water 11iI40 (Id. Separately add styrene ts
When treated with ot, benzoyl peroxide 3f, t-dodecyl mercaptan 15f, and potassium oleate obtained above, An04 particles 15 were made more lipophilic than Tok.
? The mixture was uniformly mixed by stirring at 3000 rpm under ice-cooling in advance, and the mixture was added dropwise to the four-row flask from the dropping port while stirring the polyvinyl alcohol aqueous solution inside the four-row flask. After the dropwise addition was completed, stirring was continued for 30 minutes, and when the particle size of the organic phase reached a uniform particle size of 25 μm, the temperature was raised to 75° C. for polymerization.

After 5 hours of polymerization, unreacted monomers were collected under reduced pressure, and polymer particles containing h@04 were separated by centrifugation.
By washing three times with hot water at 140 F, one coalesced particle can be obtained. As a result of determining the particle size using an electron microscope.

The particles had a diameter of 25±075 μm and were attracted by a magnet.

Example 2 In place of styrene 150 F as in Example 1, ;x,
A polymerization reaction was carried out in the same manner as in Example 1, except that a mixture of fvy147f and 3t of methacrylic acid was used. eFa@0
Polymer particles 142f containing 4 were obtained, the particle size was z2±06 μm, and they were attracted to a magnet.

Example 3 Ten weights of soluble starch were added to the four-hole flask in Example 1.
Add 400 - of aqueous solution. Styrene 120f, acrylonitrile 3Of.

Shibaazbisisobutyronitrile 25f, t-dodecyl mercaptan Lot, and average particle size 1 obtained by treating with potassium oleate in the same manner as in Example 1 to impart lipophilicity.
50 A of lead ironide 45f was stirred in advance at 8000 rpm for 30 minutes under ice-cooling, and mixed uniformly, and then added dropwise from a dropper to a four-ring flask under water-cooling at Looo rpm while stirring inside the four-ring flask. After the completion of the dropwise addition, stirring was continued for 30 minutes, and when the particle size of the organic phase reached a uniform particle size of L5 μm, the temperature was raised to 70° C. for polymerization. After polymerization for 5 hours, unreacted monomers were collected under reduced pressure (b), and polymer particles containing lead oxide were separated by centrifugation.

Polymer particles of 180f are obtained by washing three times with 500-m warm water.

As a result of determining the particle size using an optical microscope, the particle size was 165±
5.3, and the particle density was L362 (25°C).

Example 4 Styrene 120 instead of vinyl monomer in Example 3
f, acrylonitrile 281 and methacrylic acid 2t
was given hydrophilicity by treating it with potassium oleate in the same manner as in Example 1 instead of lead oxide, and the average particle size was 1.
A polymerization reaction was carried out in the same manner as in Example 3 except that oooj FazO@ (Red Garla) was used.

145 t of red polymer particles containing 20 g of Fa with a particle diameter of 215±72 μm were obtained.

Examples & Fa@O@1 with an average particle diameter of 80 μm prepared by a wet method
A solution of 30-ml of water was added to a pH 7 aqueous solution 600-ml containing 60% of fluorine at room temperature while stirring. The mixture was refluxed for 1 hour, cooled, centrifuged, washed twice with 20-g of ethanol, and dried under reduced pressure. Fa20B particles 30f styrene Zoo f
, benzoyl peroxide 3f.

t-dodecyl mercaptan LOP was cooled in advance at 50O
The mixture was mixed uniformly by stirring at rpm and added to an IL-capacity flask. Under water cooling, add 400% of a 3-fold 11% aqueous solution of polyvinyl alcohol, stir at 2000 rpm for 1 hour, and when the particle size of the cloudy droplets reaches a uniform particle size of 12 μm, raise the temperature to 75°C to polymerize. do. After polymerization for 5 hours, unreacted monomers are collected under reduced pressure, and the polymer particles are separated by centrifugation, and 100 fik4 of polymer particles containing Fa@03 are collected. The particle diameter was determined by optical microscopy and was 14±4 μm.

Comparative Example 1 Fa treated to impart stinging properties in Example 1
@ Particle size 1 prepared by wet method and dried instead of 04
A polymerization reaction was carried out in the same manner as in Example 1 except that 00A FA, O, was used.

However, JFn304 in this example precipitates in the dropping funnel, so it cannot be dropped from the dropping funnel in a uniformly dispersed state, so it is added to the four-ring flask all at once. . FaBO
After removing the precipitate from No. 4, polymer particles were recovered in the same manner as in Example 1, but these particles were not attracted to the magnet. That is, it can be seen that Fa@Q4 is not contained in the polymer particles.

l

Claims (1)

[Claims] A filler that has been treated as a filler to impart lipophilicity to its surface when a vinyl monomer containing a filler is subjected to suspension polymerization in water in the presence of a polymerization initiator and a suspension protectant. It is characterized by the use of a filler that does not aggregate in the oil-based vinyl monomer. A method for producing vinyl polymer particles containing a filler.