JPH0716607B2 - Water separation and retention agent sticking prevention method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in improved water separation and retention agents. More specifically, it relates to a method for preventing sticking of a water separation / holding agent, which is obtained by integrating a polymer obtained by insolubilizing a specified (meth) acrylamide derivative in water and a fibrous substance.

Conventional technology and its problems; Conventionally, separation of water from an aqueous solution is a general method performed in steps such as concentration of the aqueous solution, crystallization from the aqueous solution, and production of pure water.

Specific methods used in those steps include:
(1) There is a method of separating by a membrane such as reverse osmosis membrane or ultra-permeation membrane, and (2) a method of separating by phase change of water such as multi-stage flash evaporation method, freezing method, etc., which are put to practical use. There is. However, none of these methods is sufficiently satisfactory, and various improvements have been tried.

Further, in recent years, a resin which absorbs and holds water several hundred times or more its own weight, which is a highly water-absorbent resin, has been developed, and its application to various uses has been attempted.

The present inventors have conducted investigations for the above purpose, and a polymer obtained by insolubilizing a specified (meth) acrylamide derivative polymer, which is also applied to the present invention, in water is used as a water separation and retention agent. We find it suitable and have already proposed its use. Specifically, the agent absorbs and retains water by contact with liquid or gaseous water, shrinks and releases water by heating even in the presence of a large excess of water, and further absorbs and retains this water. It has a very convenient property as a water separation and retention agent that the process can be repeated. However, one drawback is that if the agent is dried and then dried in a drier or the like, a part thereof will be solidified. Therefore, it may be used repeatedly without drying or in a form such as a film. Although it can be used without any problems in the intended use, it cannot sufficiently exhibit its function in applications such as powdered use, where drying is an essential condition when repeatedly used.

Means for Solving the Problems: The inventors of the present invention have made extensive studies in view of the above problems, and found that a polymer and a fibrous substance obtained by insolubilizing a specified polymer of a (meth) acrylamide derivative in water. When integrated, the agent does not solidify even after undergoing a drying process when repeatedly used, and the water absorption capacity is hardly reduced,
Rather, it was found that the amount increased based on the weight of only the polymer excluding the fibrous substance, and the present invention was reached.

That is, the present invention is represented by the general formula (I) or (II) (In the above formula, R ₁ is a hydrogen atom or a methyl group, R ₂ is a hydrogen atom,
A methyl group or an ethyl group, and R ₃ is a methyl group, an ethyl group or a propyl group. ) General formula (In the above formula, R ₁ is a hydrogen atom or a methyl group, A is CH _{2 n} and n is 4 to 6 or CH _{2 2} OCH _{2 2.} ) N-alkyl or N-alkylene-substituted (meth) acrylamide alone or A method for preventing sticking of a water separation and retention agent, characterized by integrating a fibrous substance with a polymer obtained by insolubilizing a copolymer or a copolymer with another copolymerizable monomer in water. Is.

Examples of the monomer used in the present invention include Nn-
Propyl acrylamide, N-n-propyl methacrylamide, N-isopropyl acrylamide, N-isopropyl methacrylamide, N-ethyl acrylamide,
N, N-diethylacrylamide, N-ethylmethacrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N-acryloylpyrrolidine, N-
Methacryloyl pyrrolidine, N-acryloyl piperidine, N-methacryloyl piperidine, N-acryloyl morpholine etc. can be mentioned.

Further, as the monomer copolymerizable with the above-mentioned monomer,
Examples thereof include hydrophilic monomers, ionic monomers, lipophilic monomers and the like, and one or more kinds of these monomers can be applied.

Specifically, examples of the hydrophilic monomer include acrylamide, methacrylamide, N-methylacrylamide,
Examples include diacetone acrylamide, hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, various methoxy polyethylene glycol methacrylates, various methoxy polyethylene glycol acrylates, and N-vinyl-2-pyrrolidone. , Vinyl acetate, glycidyl methacrylate, etc. may be introduced by copolymerization and hydrolyzed to impart hydrophilicity. Examples of the ionic monomer include acrylic acid, methacrylic acid, vinyl sulfonic acid,
Acids such as allylsulfonic acid, methallylsulfonic acid, styrenesulfonic acid, 2-acrylamido-2-phenylpropanesulfonic acid, 2-acrylamido-2-methyl-propanesulfonic acid and salts thereof, N, N-dimethylaminoethyl Amine such as methacrylate, N, N-diethylaminoethyl methacrylate, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminopropyl methacrylamide, N, N-dimethylaminopropyl acrylamide, and salts thereof can be mentioned. . Also,
Various acrylates, methacrylates, acrylamides,
It is also possible to introduce methacrylamide, acrylonitrile or the like by copolymerization and hydrolyze it to impart ionicity.

Examples of the lipophilic monomer include Nn-butylacrylamide, N-tert.-butylacrylamide, Nn
-N-alkyl (meth) acrylamide derivatives such as hexyl acrylamide and N-n-octyl methacrylamide, (meth) acrylate derivatives such as ethyl acrylate, methyl methacrylate and butyl acrylate, acrylonitrile, methacrylonitrile, vinyl acetate, styrene, α -Methylstyrene, butadiene, isoprene and the like can be mentioned.

As a method of insolubilizing the above-mentioned monomer polymer in water, there are a method of insolubilizing at the time of polymerization and a method of insolubilizing by treatment after the polymerization, but as a specific insolubilizing method, at least two or more in the molecule. A method of copolymerizing a crosslinkable monomer having a double bond with the (meth) acrylamide derivative described above, a method of copolymerizing an N-alkoxymethyl (meth) acrylamide derivative, and the above lipophilic monomer and a (meth) acrylamide derivative. A method of copolymerizing, a method of polymerizing in a lump form, a method of heat-treating the polymer, etc. can be adopted.

More specifically, in the first method, as the crosslinkable monomer,
For example, N, N'-methylenebisacrylamide, N, N-diallylacrylamide, triacrylformal, N, N
-Diacryloylimide, ethylene glycol acrylate, ethylene glycol dimethacrylate, propylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butylene glycol dimethacrylate, glycerol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane Triacrylate, divinylbenzene, diallyl phthalate and the like can be used.

The N-alkoxymethyl (meth) acrylamide derivative in the second method also includes N-hydroxymethyl (meth) acrylamide, for example N-methylol (meth).
Acrylamide, N-methoxymethyl (meth) acrylamide, N-ethoxymethyl (meth) acrylamide,
N-n-butoxymethyl (meth) acrylamide, N-
tert.-Butoxymethyl (meth) acrylamide and the like can be used.

The ratio of the lipophilic monomer to the (meth) acrylamide derivative having an amphiphilic property in the third method varies depending on the combination of the (meth) acrylamide derivative and the lipophilic monomer, and cannot be generally determined. It is 1% or more, preferably 3% or more. As the method of bulk polymerization according to the fourth method, a polymer block is obtained by polymerizing as it is without diluting with a solvent to obtain a polymer block, or by polymerizing in a monomer droplet while suspending in a solvent to obtain a particulate polymer. A method etc. can be adopted.

In the method of heat-treating the polymer which is the fifth method, the heating conditions vary depending on the polymer and are not uniform, but generally, at a temperature of 60 to 250 ° C., preferably 80 to 200 ° C., bulk polymerization, The polymer obtained by suspension polymerization, solution polymerization or the like is heat-treated. At that time, in the solution polymerization, drying or evaporation of the solvent and heat treatment may be combined.

The above five methods may be adopted individually or in combination. More effective results can be obtained when used in combination.

As a more specific method of polymerization that can be adopted in producing the water separating / holding agent according to the above-mentioned method, for example, (1) a monomer is not diluted with a solvent and polymerized as it is to produce a polymer block. Method, (2) polymerizing in a solvent and then drying or distilling off the solvent to obtain a polymer, (3) method of obtaining a particulate polymer by suspension polymerization, (4) polymer by emulsion polymerization A method of obtaining a latex can be adopted. At that time, as a method for initiating the polymerization, heating alone can be used, but normally, a better result is obtained by using a polymerization initiator. The polymerization initiator is not limited as long as it has the ability to initiate radical polymerization, for example, an inorganic peroxide, an organic peroxide,
Combinations of these peroxides with reducing agents, azo compounds and the like. Specifically, ammonium persulfate, potassium persulfate, hydrogen peroxide, tert-butyl peroxide, benzoyl peroxide, cumene hydroxyperoxide, tert.
-Butyl peroxy-2-ethylhexanoate, butyl perbenzoate and the like, and as a reducing agent to be combined with them, sulfite, bisulfite, iron, copper, salts of low ionic value such as cobalt, Examples thereof include organic amines such as aniline, and reducing sugars such as aldose and ketose. As the azo compound, azobisisobutyronitrile, 2,
2'-azobis-2-amidinopropane hydrochloride, 2,2'-
Azobis-2,4-dimethylvaleronitrile, 4,4'-azobis-4-cyanovaleic acid and the like can be used. It is also possible to use two or more of the above-mentioned polymerization initiators in combination. In this case, the addition amount of the polymerization initiator is sufficient in the normally employed quantitative range.
It is in the range of 0.01 to 5% by weight, preferably 0.05 to 2% by weight.

Among the polymers obtained in this manner, a block-shaped one, or a polymer obtained by distilling off the solvent, is pulverized into a powder, or melted into a granule, a flake, a fiber or a film. By molding, the particulate polymer can be provided as it is, and the latex polymer can be formed into a film to be provided as a water separation and retention agent.

On the other hand, the fibrous substance is not particularly limited as long as it is a fibrous substance, and may be an organic substance or an inorganic substance, or a natural substance or a synthetic substance. Specifically, asbestos, rock wool, slag wool, glass fibers, inorganic fibers such as ceramics fibers, cotton, hemp, natural fibers such as pulp, wool, silk fibers, recycled fibers such as viscose rayon, copper ammonia rayon, acetate. , Synthetic fibers such as acrylic, nylon, vinylon, polyethylene, polypropylene, polyurethane, polyester and fluorine fibers.
The thickness of these fibrous substances is not particularly limited and may be thick or thin. Regarding the length and the addition amount, the form of the agent,
Although it cannot be specified uniformly because it depends on the purpose of use, method of use, etc., if the length is short or the addition amount is small, the effect is not clear, and conversely, the length is long or the addition amount is too small. When the amount is large, it becomes difficult to uniformly integrate the polymer and the fibrous substance. Approximately 0.01 cm to 5 cm in length, preferably 0.0
5 cm to 1 cm, and the addition amount is 0.1 to 75% by weight, preferably 1 to 50% by weight in the composition of the agent.

Next, there is a method of integrating these fibrous substances into a polymer to produce a water separation / holding agent. A method of polymerizing and integrating these fibrous substances during the production of the polymer, a fibrous substance after polymerization. There are a method of integrating substances by kneading, a method of integrally molding a polymer and a fibrous substance, and the like.

More specifically, the method of integration is also related to the form of the polymer, and its form cannot be uniformly defined because it depends on what purpose and method the agent is used for. However, in general, the agent is often used in the form of powder or particles, and further in the form of film. When the polymer is obtained in the form of block, it can be integrated by dispersing the fibrous substance in the monomer for polymerization, or by melting the obtained polymer and mixing with the fibrous substance. When the polymer is obtained by a polymerization method using a solvent, it can be integrated by dispersing the fibrous substance in the polymerization liquid for polymerization, or by kneading the obtained polymer gel and the fibrous substance. . On the other hand, a granular product is generally easily produced by a suspension polymerization method, but since the (meth) acrylamide derivative used in the present invention is generally highly water-soluble, the suspension polymerization method is Reversed phase suspension polymerization in which the aqueous solution or the like is dispersed in oil, salting out suspension polymerization in which a large amount of electrolyte or the like is dissolved in the aqueous solution to suppress the solubility of the monomer, and more than the cloud point of the polymer. A method such as precipitation suspension polymerization in which the polymer is precipitated by performing the polymerization at a high temperature is adopted. In any case, it can be integrated by dispersing and polymerizing the fibrous substance in the polymerization system. When the polymer is obtained as a latex, it can be integrated by mixing the latex with a fibrous substance.

The water separating / holding agent produced as described above is in a solid state, absorbs and holds water by contact with liquid or gaseous water, and shrinks by heating even in the presence of a large excess of water. It has a very specific property of discharging water. More conveniently, the process of water absorption / retention and release can be repeated. In the case of liquid water,
The amount of water absorbed by the agent varies depending on the composition, temperature, water-soluble composition, etc. of the agent, but at room temperature (25 ° C), it can absorb about 2 to 100 times as much water as its own weight, and lowers the temperature. And the absorption of water can be increased.

When the temperature of the agent that has absorbed water is raised, the agent contracts and releases water. When the temperature is further raised, even if heated above a certain temperature, the contraction of the agent becomes extremely slow and a transition point may be observed. The transition temperature is determined by the composition of the agent and can be controlled in the range of approximately 10-100 ° C. The amount of shrinkage of the agent near the transition temperature varies depending on the composition of the agent, the composition of the aqueous solution and the like, but is generally about 1 to 20 times its own weight. On the other hand, in the case of gaseous water, the amount of moisture absorbed by the agent changes depending on the composition of the agent and the temperature / humidity conditions.
It can absorb about 5 times as much water vapor as 0.1 times. Further, the agent that has absorbed moisture or the agent that has absorbed liquid water can be quickly released by placing it in an environment with a higher temperature or a lower humidity. As described above, the agent can repeat absorption and release of liquid or gaseous water, but by integrating with a fibrous substance, even if an operation of drying the agent is included in the repeating process,
The agent does not solidify and separates water efficiently.
It has the characteristic that it can be held.

As a specific method of separating water, the agent is brought into contact with an aqueous solution from which water is to be separated to absorb water, the absorbed agent is separated from the aqueous solution, and the separated agent is removed under a higher temperature atmosphere. It is possible to perform this by discharging water, and a large amount of water can be separated by repeating this series of operations. Specific examples of application of the method for separating water include concentration of various aqueous solutions, particularly foods, amino acids, proteins, polysaccharides, etc.
Concentration of aqueous solution containing substances that are easily altered by heat such as enzymes and emulsions, low temperature crystallization, crystallization of substances that are easily altered by heat, and adjustment of concentration of aqueous solution by controlling resin water absorption by temperature Method, production of pure water from various aqueous solutions, particularly production of pure water from water containing microorganisms such as bacteria.

The method of retaining water is extremely simple, and the retaining agent may be brought into contact with liquid or gaseous water. that time,
By changing the ambient temperature, it is possible to release water from the holding agent that has absorbed water, or to further absorb water,
The water absorbed at that time may be liquid or gaseous. Also, the above process can be repeated any number of times.
Therefore, by using the water separating / holding agent of the present invention, it is possible to absorb and release water without evaporation of water due to a change in ambient temperature. A very wide range of applications can be realized. Specific applications include, for example, water retention in soil, humidity control, dehydration of gas or water contained in a solution, humidification of gas, dehumidification, moisturization, protein, base material for separation resins such as enzymes, crushing of concrete, etc. , Sanitary products such as napkins, polymeric water absorbent materials such as diapers, adsorbent materials for heavy metal ions, coagulation of sludge and liquid waste, prevention of dew condensation on wall materials, ceiling materials, etc., sealing material materials for water stoppage, construction It can be applied to various applications such as raw materials for flame-retardant / sound-insulating materials, and is less soluble in aqueous solutions containing giant substances such as proteins and emulsions, which were conventionally performed using dialysis membranes. It is also possible to apply to the field of purification of those giant substances, which has been conventionally difficult, such as removal of molecular substances such as desalting from those solutions.

The shape of the water separation and retention agent of the present invention is not particularly limited, and it is a powder, a particle, a flake, a fiber, a film, or a fiber material such as a cloth or a non-woven fabric, and heat-melts them. Those integrated by wearing, bonding, etc. can be used according to the application.

Action: As described above, the water-separating / holding agent of the present invention is easily integrated with a fibrous substance by utilizing the swelling / shrinking property due to temperature change, without causing the agent to congeal. Since it can be regenerated and has excellent properties such as good shape retention after absorbing water, it has the following effects. That is, first of all, since it is not water separation that utilizes phase changes such as evaporation and freezing, it is possible to separate water at low energy cost, and does not necessarily require a large-scale device and can be installed at any place. It can be installed. Secondly, since the separation capacity of water increases as the temperature decreases, it is extremely effective for concentrating or crystallizing an aqueous solution containing a substance that is likely to be altered by heating, and for dehumidifying at low temperature. Thirdly, since the amount of water retained can be set reversibly depending on the temperature, it is possible to control the water content of the surrounding environment depending on the temperature.

The present invention will be further described below with reference to examples.

Example 1 N-acryloylpyrrolidine (507.5 g) and N, N'-methylenebisacrylamide (2.6 g) were dissolved in distilled water (1.170 g).
N-containing 5 wt% N, N'-methylenebisacrylamide
An aqueous solution of acryloylpyrrolidine was prepared. 76.5 g of nylon fiber having a length of 1 mm and a thickness of 3 denier was added to the aqueous solution, cooled to 10 ° C., transferred to a 2 l stainless steel dewar, and nitrogen was applied using a ball filter at a flow rate of 1 / min. The gas was bubbled for 1 hour. Then, a solution prepared by dissolving 2.55 g of ammonium persulfate in 10 g of distilled water and a solution prepared by dissolving 1.16 g of sodium hydrogen sulfite in 10 g of distilled water were simultaneously added to the aqueous solution to polymerize the aqueous solution adiabatically. The obtained gale was chopped and dried, and then further pulverized to collect a 20-100 mesh fraction to obtain a sample powder. The sample powder
After immersing 5 g in distilled water at 10 ° C. for sufficient swelling, the swelling gel was collected by gently depressurizing with a glass filter, and the weight thereof was measured. When the swollen gel was dried at 60 ° C. for 2 hours with a hot air circulation dryer, the weight returned to the value before swelling,
Moreover, the individual powders separated immediately, and almost none remained on the 20-mesh sieve. Swelling and drying were repeated 10 times using the sample powder, but there was no change in the swelling ratio at any point, and a powder was obtained after drying. The sample powder before and after the test was observed with a microscope, but no crushing of particles occurred.

Comparative Example 1 A sample powder was obtained in the same manner as in Example 1 except that nylon fiber was not added. When a test was conducted in the same manner as in Example 1 using the sample powder, it was 10 ° C.
Although the swelling ratio in Example 2 was 20 times, the sample powder after drying was solidified, and a part of the solidified sample mass was solidified so as not to become powdery only by hand pressing.

Example 2 When 500 g of the polymerized gel obtained in Comparative Example 1 was shredded using a meat chopper, 30 g of polyester fiber having a length of 5 mm and a thickness of 5 denier was added, kneaded, shredded, and dried. Further, it was pulverized to obtain a sample powder. The sample powder
Disperse 1g uniformly on the surface of polypropylene-rayon non-woven fabric (weight 1.1g) of 10cm x 10cm size, overlay the same non-woven fabric on top, and heat-melt the upper and lower non-woven fabrics in a 1cm square grid pattern. By wearing, a non-woven fabric sample in which sample powder was sandwiched was prepared. When a test was conducted using the sample in the same manner as in Example 1, the sample absorbed 16 g of water at 10 ° C. Further, the sample after drying did not show any change in its shape, appearance, texture, etc. from that before the test.

Example 3 A sample powder was obtained in the same manner as in Example 1 except that 38.3 g of polyethylene fiber having a length of 2 mm and a thickness of 4 denier was used instead of the nylon fiber. 10 g of the sample powder was sprayed on a 200-mesh wire net and left in a constant temperature and humidity chamber adjusted to a temperature of 10 ° C. and a relative humidity of 98%. After 10 hours, 0.57 g of the sample powder was added per 1 g of the sample powder. It was absorbing moisture.
Then, the hygroscopic sample powder was subjected to a temperature of 40 ° C and a relative humidity of 40%.
When the sample was left to stand in a thermo-hygrostat adjusted to 1, the amount of moisture absorbed per 1 g of the sample powder was 0.08 g after 1 hour, and the individual powder was immediately separated into 20 mesh. Almost nothing remained on the sieve.

Claims (1)

[Claims] 1. Represented by the general formula (I) or (II) (In the above formula, R ₁ is a hydrogen atom or a methyl group, R ₂ is a hydrogen atom,
A methyl group or an ethyl group, and R ₃ is a methyl group, an ethyl group or a propyl group. ) (In the above formula, R ₁ is a hydrogen atom or a methyl group, A is CH _{2 n} and n is 4 to 6 or CH _{2 2} OCH _{2 2.} ) N-alkyl or N-alkylene-substituted (meth) acrylamide alone or Prevention of water separation and sticking of retention agent, characterized by integrating fibrous substance with a polymer obtained by insolubilizing a copolymer or a copolymer with other copolymerizable monomer in water Method.