JPS63221116A - Method for producing particulate polymer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing particulate polymers. More specifically, a method for producing particulate polymers made of polymers of specific (meth)acrylamide derivatives will be described.

[Prior art and its problems]

A water-insolubilized polymer of a specific (meth)acrylamide derivative absorbs water in an aqueous solution and becomes a hydrogel. The water-containing gel has temperature sensitivity in that the amount of water absorbed changes depending on the temperature, and its use is being investigated in a variety of fields by taking advantage of this characteristic. In addition, the water-insolubilized polymer of the (meth)acrylamide derivative has the characteristic that in an aqueous solution, it becomes hydrophobic when heated, and becomes hydrophilic when cooled, changing from hydrophobic to hydrophilic depending on the temperature, and can be used as a separation functional material. Applications are also being considered.

However, in any case, it is necessary to shape the material according to the purpose, especially when applied to separation functional materials.
Particulate polymers are essential.

Conventionally, as a method for producing particulate polymers, there is a suspension polymerization method in which a continuous water layer is used when the polymer is hydrophobic, whereas a continuous oil layer is used when the polymer is hydrophilic. There is a so-called inverse layer suspension polymerization method.

G, L, 5ta are methods for producing particulate polymers by inverse suspension polymerization using (meth)acrylamide derivatives as one component.
hl etc., J, Aw, Chem, Soc, +10
1 +5383 to 5394 (I979) and,
Varadarajan et al., BjOpOl)llIer
s+η, 839-847 (I983).

However, in either case, the amount of crosslinking monomer added is as high as 5.4% or 9.0% by weight, and the produced polymer has a high degree of crosslinking, and the swelling degree of the polymer with water is extremely high. becomes smaller.

As mentioned above, the present inventors focused on the fact that the water-swollen gel of a water-insolubilized polymer of a specific (meth)acrylamide derivative changes its properties by changing the temperature. A study was conducted with the aim of producing particulate polymers with low swelling properties and high water swelling properties.

However, although a particulate polymer was produced by the method described above, it was not possible to produce a particulate polymer as shown in the comparative example described below.

[Means for solving problems]

As a result of intensive studies in view of the above points, the present inventors discovered that particulate polymers can be suitably produced by reverse phase suspension polymerization in the presence of a maleic anhydride polymer, and have thus arrived at the present invention. It was.

That is, the present invention relates to a general formula represented by the general formula (T) or the general formula (■) (in the above formula, R1 is a hydrogen atom or a methyl group, R: is a hydrogen atom, a methyl group or an ethyl group, and R1 is a methyl group). , represents an ethyl group or a propyl group, ) general formula (in the above formula, R9 is a hydrogen atom or a methyl group, A is -(CH
zh′7! n is 4 to 6 or -(CHz juice 0-(CHz)
r represents an aqueous solution consisting of one or more N-alkyl or N-alkylene substituted (meth)acrylamides and a crosslinkable monomer, or one or more of the above N-alkyl or N-alkylene substituted (meth)acrylamides, Polymerization in the presence of a maleic anhydride polymer in a method for producing particulate polymers by dispersing and polymerizing an aqueous solution of other electrically capable monomers and crosslinkable monomers in oil. A method for producing a particulate polymer characterized by the following.

The specific (meth)acrylamide derivatives used in the present invention are N-alkyl or N-alkylene substituted (meth)acrylamides represented by general formulas (I) and (II), and specifically, For example, N-ethylacrylamide, N,N-diethylacrylamide, N-ethylmethacrylamide, N,N-dimethylacrylamide, N
, N-dimethylmethacrylamide, N-isopropylacrylamide, N-n-propylacrylamide, N-
Isopropyl methacrylamide, N-n-propyl methacrylamide, N-acryloylpyrrolidine, N-methacryloylpyrrolidine, N-acryloylpiperidine,
Examples include N-methacryloylpiperidine, N-acryloylhexahydroazepine, and N-acryloylmorpholine.

Among the above-mentioned monomers, those which are liquid monomers and have high solubility in water are preferred for polymerization. Specifically, for example, N-ethylacrylamide, N,N-diethylacrylamide, N-ethylmethacrylamide,
N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N-n-propylacrylamide, N
-Acryloylpyrrolidine, N-methacryloylpyrrolidine, N-acryloylbiveridine, N-acryloylmorpholine, and the like.

In addition, monomers that can be copolymerized with the above monomers include:
Examples include hydrophilic monomers, ionic monomers, lipophilic monomers, etc., and one or more of these monomers can be applied. Specifically, as a hydrophilic monomer, for example, acrylamide, methacrylamide, diacetone acrylamide, hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, various methoxypolyethylene glycol (meth)acrylates, N-vinyl -2-pyrrolidone, etc. can be mentioned, and vinyl acetate, glycidyl methacrylate, etc. can also be introduced by copolymerization and hydrolyzed to impart hydrophilicity.

Examples of ionic monomers include acrylic acid, methacrylic acid, vinylsulfonic acid, allylsulfonic acid, methallylsulfonic acid, styrenesulfonic acid, 2-acrylamido-2-phenylpropanesulfonic acid, and 2-acrylamido-2-methyl. -Acids such as propanesulfonic acid and their salts, N,N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl methacrylate, N,
Examples include amines such as N-dimethylaminoethyl acrylate, N,N-dimethylaminopropylmethacrylamide, N,N-dimethylaminopropylacrylamide, and salts thereof. It is also possible to introduce various acrylates, methacrylates, acrylamide, methacrylamide, acrylonitrile, etc. by copolymerization and hydrolyze them to impart ionicity.

Examples of the lipophilic monomer include N,N-di-n-propylacrylamide, N-n-butylacrylamide,
N-n-hexyl acrylamide, N-n-hexyl methacrylamide, N-n-octylacrylamide, N
-n-octyl methacrylamide, N-tert-octylacrylamide, N-dodecyl acrylamide, N
N-alkyl (meth)acrylamide derivatives such as -n-dodecylmethacrylamide, N,l1l-diglycidyl acrylamide, N,N-diglycidylmethacrylamide, N-(4-glycidoxybutyl)acrylamide,
N-(4-glycidoxybutyl)methacrylamide, N
-(5-glycidoxypentyl)acrylamide, N-
N- such as (6-gelicidoxyhexyl)acrylamide
(ω-glycidoxyalkyl) (meth)acrylamide derivative, ethyl acrylate, methyl methacrylate,
(Meth)acrylate derivatives such as butyl methacrylate, butyl acrylate, lauryl acrylate, 2-ethylhexyl methacrylate, glycidyl methacrylate, olefins such as acrylonitrile, methacrylaterile, vinyl acetate, vinyl chloride, vinylidene chloride, ethylene, propylene, butene, Examples include styrene, divinylbenzene, α-methylstyrene, butadiene, and isoprene.

On the other hand, there are two types of crosslinkable monomers: monomers that have two or more polymerizable groups in their molecules, and monomers that have functional groups that induce crosslinking through post-treatments such as heating after polymerization. . As a monomer having two or more double bonds in one molecule of the former,
Specifically, alkylene bisacrylamides such as methylene bisacrylamide and ethylene bisacrylamide, alkylene di(meth)acrylates such as ethylene di(meth)acrylate, polyethylene glycol di(meth)acrylate, bisphenol A di(meth)acrylate, etc. Di(meth)acrylates of various bisphenol A derivatives, di-, tri-, or tetra(meth)acrylic acid esters of polyhydric alcohols such as glycerin and pentaerythritol, di- or tri(meth)acrylates of ethylene oxide-modified phosphoric acid, oligoesters (meth) )
Examples include di- or tri(meth)acrylic acid esters of acrylate, polyester (meth)acrylate, urethane acrylate, incyanurate, or derivatives thereof.

On the other hand, examples of post-crosslinkable monomers include N-methylol acrylamide, N-methylol methacrylamide,
N-methoxymethylacrylamide, N-ethoxymethylacrylamide, N-n-propoxymethylacrylamide, N-butoxymethylacrylamide, N-
Examples include N-alkoxymethyl (meth)acrylamide derivatives such as n-butoxymethylmethacrylamide, N-isobutoxymethylacrylamide, and Nt-octoxymethylacrylamide.

The quantitative ratio of the (meth)acrylamide derivative to the other copolymerizable monomers mentioned above varies depending on the combination of these monomers; Each monomer accounts for 80% by weight of the total amount of monomers.
or 40% by weight or less, preferably 60% by weight or 30% by weight or less, respectively. On the other hand, the lipophilic monomer accounts for 40% by weight or less, preferably 20% by weight or less, based on the total amount of monomers.

Next, in the conventional method, the quantitative ratio of the crosslinking monomer to the above-mentioned monomers was 5% by weight or more based on the total amount of monomers, but according to the method of the present invention, the quantitative ratio was 0. Particulate polymers can be suitably produced even with a degree of crosslinking as low as 0.05% by weight, preferably 0.1% by weight. That is, in the past, at such a low degree of crosslinking, particles coalesced, and particle dispersion during polymerization was not successful. However, by including the maleic anhydride polymer of the present invention in the polymerization mixture, the polymer particles can be suitably dispersed, making it possible to produce the above-mentioned particles with a low degree of crosslinking.

Furthermore, polymerization can be carried out in a well-dispersed state over a wide range of concentrations of the monomers mentioned above in the aqueous solution, from 5% by weight to 90% by weight, preferably from 10% to 85% by weight. The properties of the polymer obtained by polymerization over such a wide range of concentrations differ between those obtained at low concentrations and those obtained at high concentrations, and are Even if the ratio of polymerization is the same, a product polymerized at a low concentration will swell more with water than a product polymerized at a high concentration, and the swollen gel will be more elastic6. The polymerized product can be used as it is as a granular polymer without drying.

Next, it is essential that the components constituting the continuous layer, ie, the oil layer, in which the aqueous monomer solution described above is dispersed in the form of particles have properties that are incompatible with water.

Specific examples include aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbon compounds, and compounds in which these compounds are substituted with halogen atoms.

Examples of the aliphatic hydrocarbon compound include single compounds such as hexane, heptane, decane, and tetradecane, as well as petroleum ether consisting of mixed components, kerosene, light oil, lubricating oil, liquid paraffin, and the like. Examples of the alicyclic hydrocarbon compound include cyclopentane, cyclohexane, cyclohexene, dicyclopentadiene, and the like.

Examples of aromatic hydrocarbon compounds include benzene, toluene, xylene, ethylbenzene, and cumene. Further, halogen-substituted hydrocarbon compounds, which may be mixtures of the above-mentioned aromatic and non-aromatic hydrocarbons, are mainly aliphatic hydrocarbon compounds substituted with halogen atoms, and specifically include, for example, dichloromethane, chloroform, Examples include chlorinated paraffin, which is obtained by chlorinating a mixture of carbon tetrachloride, dichloroethane, trichloroethane, dichloroethylene, trichloroethylene, tetrachloroethylene, and aliphatic hydrocarbon compounds.

Among the above, aliphatic and alicyclic hydrocarbon compounds are preferred, as these compounds generally have a specific gravity of less than 1.
In order to better disperse the monomer aqueous solution, a halogen-substituted hydrocarbon compound is added to reduce the specific gravity of the oil layer to 1.
It is also possible to create a good dispersion state by approaching .

However, simply mixing the monomer aqueous solution and the above-mentioned hydrocarbon solvent does not maintain a good dispersion state.
It is necessary to add a dispersant. In the present invention, it is essential to use a maleic anhydride polymer as an additive.

Maleic anhydride polymers include maleic anhydride and butene, octene, decene, and dodecene5. It is an alternating copolymer with α-olefins such as octadecene, eicosene, and tetrachloro, or with styrene. It can be easily produced by radical polymerization, and is commercially available as a polymeric surfactant and paper sizing agent, with a molecular weight of several hundreds. ~ It's about the enemy side.

Among the above, maleic anhydride and long chain α-
Examples include copolymers with olefins.

Furthermore, other types of dispersants can also be used together with the maleic anhydride polymer. Specific examples include sorbitanic acid mono- or diester, fatty acid alkanolamide, cellulose ester, and polyester-ether-ester.

Next, the aqueous monomer solution is dispersed in the oil layer and polymerization is started to produce a granular polymer.First, the ratio of the aqueous monomer solution to the oil layer is such that production can be carried out more favorably if the ratio of the aqueous monomer solution to the oil layer is increased. Specifically, when the volume of the monomer aqueous solution is 1, the volume of the oil layer is approximately in the range of 1 to 25. If the volume of the oil layer is too small, polymer particles tend to coalesce, while if it is too large, the volume The production efficiency of per-particle particles decreases, which is inconvenient.

In addition, the amount of maleic anhydride polymer added is approximately 0.02 to 1.0% by weight based on the oil layer; if the amount added is too small, coalescence of the polymer particles will occur, while if it is too large, coalescence of the polymer particles will occur. The amount of maleic anhydride polymer incorporated into the polymer particles is large (which is disadvantageous).

Next, as mentioned above, the monomer aqueous solution is dispersed in the oil layer to initiate polymerization.The polymerization initiator used therein is preferably a water-soluble radical polymerization initiator, which is usually dissolved in the monomer aqueous solution. used. Specifically, peroxides include ammonium persulfate, potassium persulfate, hydrogen peroxide,
Examples include tart-butyl peroxide. In this case, it can be used alone, but it can also be used as a redox polymerization initiator in combination with a reducing agent. Examples of reducing agents include sulfites, hydrogen sulfites, salts with low ionic valences such as iron, copper, and cobalt, organic amines such as N, N, N', N'-tetramethylethylenediamine, and aldose. Examples include reducing sugars such as ketose.

Examples of azo compounds include 2,2'-azobis-2-amidinopropane hydrochloride, 2,2°-azobis-2,4-
Dimethylvaleronitrile, 4.4"-azobis-4-cyatubaleic acid and its salts, etc. can be used.

It is also possible to use two or more of the above polymerization initiators in combination. The amount of initiator added is from 0.1 to monomer.
10% by weight, preferably 0.2-8% by weight. Further, in the case of a redox system, the amount of reducing agent added to the initiator is 0.1 to 10.0%, preferably 0.1 to 10.0%, on a molar basis.
It is 2 to 8.0%.

Specifically, the method for producing a particulate polymer is to first dissolve or disperse a maleic anhydride-based polymer in an oil layer, add an aqueous monomer solution thereto, and disperse the aqueous monomer solution into particles in the oil. Disperse in a shape. The stirring speed at that time is 50-500 rpm.
m, and there is no need to keep it constant during polymerization, and it may be adjusted depending on the state of particle dispersion. At this time, it is preferable that the atmosphere in the reaction system be replaced with a reduced amount of oxygen, specifically, with an inert gas such as nitrogen gas.

Next, polymerization can be initiated by heating when a single polymerization initiator is used. Further, in the case of a redox polymerization initiator, either an oxidizing component or a reducing component may be used, but polymerization can usually be initiated by adding a reducing component later.

When using a single polymerization initiator, the polymerization temperature is approximately 30~30°C.
90″C, and in the case of a redox polymerization initiator,
The temperature is lower, approximately 5 to 50°C.

The polymerization time is not particularly limited, but it is generally 1 to 20 hours.During the polymerization, it is possible to enlarge the polymer particles, change the composition, etc. by adding an aqueous monomer solution of the same or different composition. can.

The state of polymerization can be monitored by sampling the polymer and measuring the presence or absence of polymer particles, the rate of decrease in monomers, etc.

Next, after polymerizing at a predetermined temperature and time as described above, a particulate polymer can be obtained by filtering the polymerization liquid. As a method for filtering, pressure filtration, reduced pressure filtration, natural filtration, centrifugation, etc. can be used.

The particulate polymer thus obtained can be put to practical use as it is if the water content is small. On the other hand, if the water content is high or if the particles are to be made into dry particles, it is sufficient to dry the particles. Furthermore, to obtain a particulate polymer with less adhesion of the maleic anhydride group polymer, alcohol such as methanol or acetone can be used. The particles may be washed with a polar solvent such as

The particulate polymer that can be produced by the above method has a particle size of 10
It is a spherical particle in the range of ~1000μ, and its particle size and particle size distribution are influenced by the stirring speed, the amount of maleic anhydride polymer added, and the ratio of the monomer aqueous solution to the oil layer.
At high speed, high addition amount, and high oil layer ratio, the particle size becomes smaller and the particle size distribution becomes narrower.

Further, the particulate polymer absorbs water and swells to form a gel, and in many cases, the amount of swelling of the gel changes depending on the temperature.

In other words, the amount of swelling increases at low temperatures, and as the gel contracts and the swelling decreases with heating, the amount of swelling changes depending on the polymer composition, but at 10"C, the maximum amount is approximately 10 of its own weight.
At 60° C., it is about 10 times its own weight or less, and the process can be repeated any number of times. Such high swelling is achieved by reducing the amount of crosslinking monomer added and by lowering the monomer concentration during polymerization.

〔Effect of the invention〕

By the method of the present invention, a particulate polymer whose water swelling amount changes depending on temperature can be produced, and has the following characteristics.

(I) Low degree of crosslinking spherical particles having very high water swelling ability can be produced.

(2) The monomer aqueous solution concentration during polymerization can be selected over a very wide range, and polymerization can be performed at almost any concentration.

(3) Since the aqueous monomer solution can be stably dispersed in oil, the stirring speed can be set arbitrarily, and the particle size of the particles can be easily controlled.

Since the particulate polymer produced by the method of the present invention has a spherical shape, it is much easier to handle than powdered products (and has the characteristic that the amount of water swelling changes depending on the temperature, so it can be used in many ways). Specifically, it can be applied to the concentration of various aqueous solutions, especially the concentration of aqueous solutions containing substances that are difficult to concentrate by evaporation, such as foods, amino acids, proteinaceous substances, class II proteins, enzymes, and emulsions that are easily altered by heat. It can also be used as a water retention agent for soil water retention and humidity control.

Furthermore, as a base for separation chromatography, for example, gel filtration agents,
It can also be used as an adsorbent or as a microcarrier for supporting cells. - It can also be used as a carrier for sustained-release drugs by utilizing its property of swelling not only in water but also in organic solvents such as alcohol, acetone, dimethylformamide, and dioxane.

[Example] Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples.

Example 1 52 m of n-hexane and 281 d of carbon tetrachloride were charged into a 3001 Idl round bottom flask equipped with a stirrer, a thermometer, a condenser, and a ball filter, and a copolymer of octadecene l and maleic anhydride was added as a dispersant. Coalescing linear polymer (PA-18, Gulf Oil Chewtc
alsCo, ) was added and stirred for over 15 minutes to swell the dispersant. Then, the mixed solution was gently purged with nitrogen for 30 minutes or more using a Pall filter.

N-acryloylpyrrolidine (hereinafter abbreviated as N-APR)
2.97g, methylenebisacrylamide (hereinafter referred to as MB
Dissolve 0.03 g of ammonium persulfate (hereinafter referred to as APS) in 17.00 g of distilled water and replace with nitrogen.
0.05g was added and completely dissolved.

The aqueous monomer solution was slowly poured into the organic solvent prepared above, and the stirring speed was gradually increased to 200 rpm. After stirring for 15 minutes to stabilize the particles, 0.101 d of N,N,N',N'-tetramethylethylenediamine (TMEDA) was added and polymerized for 1.5 hours. After polymerization, the aqueous solution proceeded in a uniformly dispersed state and the polymer was obtained as spherical particles.
The reaction mixture was poured into a glass filter to filter out the beads. The beads were thoroughly washed with acetone and then immersed in a large amount of distilled water.

The yield of the obtained pieces was 93% based on the amount charged. The dry particle size of pieces synthesized at a stirring speed of 200 rpm is 80 to 350 μ, and the effective particle size is 145 μ.
The uniformity factor was 1.31. The amount of water swelling per gram of dry particles at each temperature was measured and shown in Table 2.

Furthermore, when the dry particulate polymer was swollen in ethanol and the amount of swelling was measured, it was found to be 26.5 d/cm at 10°C.
g, 25.9d/g at 25℃, 25.6d at 50℃
/g.

Comparative Example 1 Polymerization was carried out in the same manner as in Example 1 except that 0.1 g of sorbitan sesquiolate was added instead of PA-18.

As the polymerization progressed, particles of the aqueous monomer solution began to coalesce and adhered to the stirrer, making it impossible to produce a particulate polymer.

Examples 2 to 9 Particulate polymers were produced in exactly the same manner as in Example 1 except for the polymerization conditions shown in Table 1. In either case, the polymerization proceeded in a state where the aqueous monomer solution was uniformly dispersed, and the polymer was obtained as spherical particles.

Next, the swelling amount of the particulate polymer in distilled water was adjusted to 10°C.
, 25°C, and 50°C, and the measurement results are shown in Table 2.

Table-2

Claims (1)

[Claims] General formula represented by general formula (I) or general formula (II) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (I) (In the above formula, R_1 is a hydrogen atom or a methyl group, R_2 is Hydrogen atom, methyl group or ethyl group, R_3 represents methyl group, ethyl group or propyl group.) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (II) (In the above formula, R_1 represents a hydrogen atom or methyl group, A is -(C
H_2)-_n, where n is 4 to 6 or -(CH_2)-_2
Represents O-(CH_2)-_2. ) An aqueous solution consisting of one or more N-alkyl- or N-alkylene-substituted (meth)acrylamides and a crosslinkable monomer, or copolymerization of one or more of the above N-alkyl- or N-alkylene-substituted (meth)acrylamides and other A method for producing a particulate polymer by dispersing and polymerizing an aqueous solution of a crosslinkable monomer and a crosslinkable monomer in oil, characterized in that the polymerization is carried out in the presence of a maleic anhydride polymer. Method for producing particulate polymer.