JPS60168705A - Temperature-sensitive polymer - Google Patents

Abstract

PURPOSE:A temperature-sensitive polymer whose cloud point can be set over a wide range of temperature, comprising a (co)polymer of a specified unsaturated amide compound. CONSTITUTION:An unsaturated amide compound of the formula (wherein R is H or methyl, and n is 4-10), e.g., N-acryloylpyrrolidine or N-acryloylhexahydroazepine, is homopolymerized or copolymerized with other monomers (e.g., acrylamide, acrylic acid, or N,N-diethylmethacrylamide). By suitably selecting the monomer, it is possible to control the cloud point (a temperature at which an aqueous solution of the polymer becomes turbid when heated) of the obtained temperature-sensitive copolymer arbitrarily within the range of about -10- 110 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to temperature-sensitive polymers. More specifically, the present invention relates to a temperature-sensitive polymer comprising a polymer of an unsaturated amide compound.

Conventionally, temperature-sensitive polymers that become insolubilized in water by heating in an aqueous solution, that is, specifically, become cloudy and opaque, include polyethylene oxide or a copolymer of ethylene oxide and propylene oxide, methyl cellulose, Polymethylvinyl cellulose and the like are known. However, when producing these polymers, there are various problems such as the need for special equipment or technology for handling and polymerization of raw monomers, and the need for reactions under harsher conditions. there were.

In recent years, it has been reported that certain polymers of acrylamide or methacrylamide derivatives (hereinafter abbreviated as (meth)acrylamide derivatives), such as N-propylacrylamide, can be whitened and insolubilized by heating in an aqueous solution. , 84ACROMOL, SC1,-
CHE)/L, Volume A2, 1441-. 1455 pages (19
(published in 1968), and similar technology has recently been disclosed in Japanese Patent Application Laid-Open Nos. 58-174408 and 58-20665.
4, and diethylacrylamide is disclosed in JP-A-58-206655.

Since these (meth)acrylamide derivatives are generally in the form of powder or liquid with a high boiling point, they are easy to handle and have the advantage of being easily polymerized by methods such as radical polymerization. However, according to the disclosed technology, the temperature at which a (meth)acrylamide derivative polymer becomes insoluble in water and becomes cloudy (hereinafter abbreviated as clouding point) by heating it in water is about 20 to 40°C. Since it is unevenly distributed in the range of , it has become a practical problem.

As a result of intensive studies in view of the above circumstances, we found that unsaturated amide compounds represented by the general formula below, either alone or as copolymers, or other copolymers (R is hydrogen or a methyl group; (This is an integer of 10.) The present invention was achieved by discovering that a temperature-sensitive polymer made of a copolymer with a monomer can solve these problems.

In the present invention described above, as other copolymerizable monomers, one or more of hydrophilic monomers, ionic monomers, and lipophilic monomers can be used. The above hydrophilic monomers include:
For example, acrylamide, methacrylamide, N-methylacrylamide, N,N-dimethylacrylamide,
N,N-dimethylmethacrylamide, N-ethylacrylamide, N,N-diethylacrylamide, N-n-
Propylacrylamide, N-n-propylmethacrylamide, N-isopropylacrylamide, N-inpropylmethacrylamide, diacetone acrylamide,
Hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, various methoxypolyethylene glycol methacrylates, various methoxypolyethylene glycol acrylate-1-, N-vinyl-2-
Examples include pyrrolidone, and vinyl acetate, glycidyl methacrylate, etc. can also be introduced by copolymerization and hydrolyzed to impart hydrophilicity. Examples of the ionic monomer include acrylic acid, methacrylic acid, vinylsulfonic acid, allylsulfonic acid, methallylsulfonic acid, styrenesulfonic acid, 2-acrylamido-2-phenylpropanesulfonic acid, and 2-acrylamido-2 -'f Acids such as propanesulfonic acid and their salts, N,N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl methacrylate, N
, N-dimethylaminoethyl acrylate, N,N-dimethylaminopropylmethacrylamide, N,N-dimethylaminepropylacrylamide, 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-diethylmethacrylamide, N,N-di-n-propylacrylamide,
N-n-butylacrylamide, N-n-butylmethacrylamide, N-tert,-butylacrylamide,
N-tert, -butyl methacrylamide, N-n-hexyl acrylamide, I'J-n-hexyl methacrylamide, N-n-octylacrylamide, N-n-
5N-alkyl (meth)acrylamide derivatives such as octyl methacrylamide, N-te, -octylacrylamide, N -+1-dodecyl acrylamide, N-n-dodecyl methacrylamide, ethyl methacrylate, methyl methacrylate-1, , (meth)acrylate derivatives such as butyl methacrylate, butyl acrylate, lauryl acrylate, 2-ethylhexyl methacrylate-1, glycidyl methacrylate, acrylonitrile,
Examples include vinyl acetate, vinyl chloride, styrene, and α-methylstyrene.

Specific methods for producing a temperature-sensitive polymer by polymerizing the above-mentioned unsaturated amide compound include (1) a method of producing a polymer block by directly polymerizing the monomer without diluting it with a solvent; (2) In the method of obtaining a polymer by polymerizing in a solvent, there are cases in which the solvent is distilled off from the polymer solution or the precipitated polymer is separated in a furnace, and cases in which the polymer is obtained as is, and cases in which the polymer solution is used as it is (3). A method of obtaining a particulate polymer by suspension polymerization, a method of (4) obtaining a polymer latex by emulsion polymerization, etc. can be adopted. In this case, the polymerization mode can be radical polymerization or anionic polymerization as in the case of ordinary N-substituted (meth)acrylamide.

Among these, radical polymerization is preferable because polymerization methods in various forms can be easily employed.

As a method for initiating polymerization, a method using a polymerization initiator, a method using light or heat, or a method of irradiating high energy rays such as radiation, electron beam, plasma, etc. can be adopted. Among the above methods, the method using a polymerization initiator is particularly preferable because it not only simplifies the monopolymerization process but also facilitates the control of the polymerization. The polymerization initiator is not limited as long as it has the ability to initiate radical polymerization, and includes, for example, inorganic peroxides, organic peroxides, combinations of these peroxides and reducing agents, and azo compounds. . Specifically, ammonium persulfate, potassium persulfate, hydrogen peroxide, tert, -butyl peroxide, benzoyl peroxide, cumene hydroxy peroxide, tert, -butyl peroxy-2-ethylhexanoate, butyl perbenzoate. Reducing agents that can be combined with these include sulfites, hydrogen sulfites, salts with low ionic valences such as iron, copper, and cobalt, organic amines such as aniline, and reducing sugars such as aldoses and ketoses. be able to. Examples of the azo compound include azobisisobutyronitrinope 2,2'-azobis-2-amidinoglopane hydrochloride, 2,2'-azobis-
2+4-dimethylvaleroni l-IJ /lz, 4-4'
-Azobis-4-cyatubaleic acid and the like can be used. It is also possible to use two or more of the above polymerization initiators in combination. In this case, the amount of the polymerization initiator to be added is sufficient to be within a commonly employed quantitative range, for example, from 0.01 to 5% by weight, preferably from 0.05 to 2% by weight, based on the monomer.

Among the polymers obtained in this way, polymers in the form of prongs and those obtained by distilling off the solvent or separating the precipitated polymers are crushed into powder or melted into granules, flakes, fibers, or films. Particulate polymers can be used as they are, latex polymers can be impregnated onto fibrous materials such as cloth and paper, or made into films, and liquid products can be obtained by dissolving the above polymers in an aqueous solution. It can be provided as a temperature-sensitive polymer in the form of

When the temperature-sensitive polymer produced as described above is in the solid state σ5, it is stored in an aqueous solution, and when it is dissolved in an aqueous solution, it is used as it is.

The temperature-sensitive polymer of the present invention becomes insolubilized by heating while dissolved in an aqueous solution, and the temperature at which it becomes insolubilized is expressed as a dot. The specific method of insolubilization by heating varies depending on the type of polymer and cannot be described uniformly, but in general, upon heating, the entire solution first becomes white and translucent, and then becomes cloudy. At that time, the temperature range from translucency to cloudiness varies depending on the concentration and type of polymer, but is generally below 5.6°C. This cloudy liquid generally has the same appearance as an aqueous emulsion solution, is white and opaque, and exists stably without phase separation if the temperature is kept above the image point. However, depending on the concentration and type of polymer, after the white cloudiness, the white cloudy substances may associate with each other over time, forming spherical or string-shaped precipitates, or even adhere to the vessel wall, etc., resulting in phase separation. There is. Naturally, the higher the concentration, the higher the opacity, and depending on the type of polymer, phase separation becomes easier.

On the other hand, when the solution that has become white and opaque due to heating as described above is cooled, it becomes transparent near the image point. This process can be repeated any number of times.

Next, the concentration of the polymer in an aqueous solution at which the above phenomenon occurs varies depending on the type of polymer and its molecular weight and cannot be stated unconditionally, but it is generally a concentration of several hundred yen) 11 or more.

As a matter of course, as the concentration of the polymer becomes dilute, the turbidity upon heating decreases, the polymer becomes translucent, and the opacity increases.

On the other hand, the upper limit of the polymer concentration may be in a state where fluidity is lost as long as it is in a water-containing state, and is approximately 70% solubility.

Further, the aqueous solution or liquid in which the above polymer is dissolved may be any medium containing water, and water itself is most preferable. Various types of water can be used, such as tap water, industrial water, ion exchange water, and distilled water. Any solvent that can be used miscibly with water may be used as long as it is miscible with water, such as methanol,
Alcohols such as ethanol, ketones such as acetone,
glycols such as ethylene glycol and propylene glycol; cyclic ethers such as dioxane and tetrahydrofuran; N,N-dimethylformamide;

These include amide solvents such as N-dimethylacetamide, nitriles such as acetonitrile, glymes such as tetraglyme, and dimethyl sulfoxide.

Methods for observing the above-mentioned phenomenon of insolubilization due to heating include direct visual observation, a method of detecting cloudiness due to insolubilization using a turbidity meter, an ultraviolet or visible absorption photometer, or the like. On the other hand, indirect methods include methods of measuring the solution viscosity of an aqueous polymer solution by changing the temperature, and methods of detecting changes in other physical properties due to insolubilization, such as measuring the spread of molecules by changing the temperature using a light scattering method. It can also be done by

By employing the polymer of the present invention, the problem of the aqueous polymer solution measured in this manner can be controlled between -10°C and 110°C, preferably between 0°C and 100°C. That is, by employing the polymer of the present invention, -10
It is possible to provide polymers having a temperature of 0.degree. C. to 110.degree. C., preferably 0.degree. C. to 100.degree.

As a specific method for controlling the issue, if the set temperature and the issue of the homopolymer match, the polymer may be used as is. However, if the set temperature and the issue do not match, or if you want to subtly change the issue, the issue can be changed by copolymerization.

In the case of copolymerization, two or more types of monomers that are in dispute are copolymerized, and one or more types of monomers that are in dispute are copolymerized with one or more other monomers that can be copolymerized. may be copolymerized. In the former case, acidification properties often exist between the copolymer composition and the issues of each homopolymer, so if the set temperature is between the two issues, each monomer By determining the ratio of , it is possible to tentatively determine the issue of the copolymer, but since there are many cases that deviate from this general rule, it is preferable to confirm by experimenting with various combinations. Furthermore, by slightly changing the ratio of each monomer, it is possible to change the issue. Examples of monomers in which the polymer is controversial include the unsaturated Amita F-do compound represented by the general formula in the present invention, N-inglovir acrylamide, N-isopropyl methacrylamide, N-n
Examples include nipropylacrylamide, N-n-propylmethacrylamide, N,N-diethylacrylamide, and the like, which are applicable.

In the latter case, one or more of the above-mentioned hydrophilic monomers, ionic monomers, and lipophilic monomers can be employed as other copolymerizable monomers. In that case, the points at issue regarding the copolymer will change due to the introduction of those monomers, but it is difficult to predict the changes in the points at issue depending on the type of copolymer, the amount added, and the differences in the polymerization method. They are different and difficult to achieve uniformly.

However, it is preferable to introduce a hydrophilic monomer into Y in general.

Next, a specific method for making the above temperature-sensitive polymer insolubilized in water by heating basically involves dissolving the above polymer in water and bringing it into contact with a heating medium having a temperature higher than the temperature at issue. Bye. Due to this contact, the solution becomes cloudy and the polymer becomes insolubilized. More specifically, the polymer aqueous solution may be placed in an ordinary container, sandwiched between plate-like or membrane-like bodies such as plates, sheets, or films, placed in a tube, sandwiched between double tubes, or beaded. Fix the microspheres by a method such as making them into microspheres, and expose them to sunlight, ultraviolet rays, visible light, infrared rays, far infrared rays, laser beams, etc.; Contact them with a heating medium such as hot water or steam; or The polymer can be insolubilized by heating by blowing into the solution, and as a result, the aqueous solution becomes cloudy and becomes white and opaque.

Specific application examples of the temperature-sensitive polymer of the present invention include greenhouses,
Light-shielding materials that block light at a certain temperature for greenhouses, residential window glass, solar water heater lids, etc.; reproducible recording materials; reproducible display materials; temperature-sensitive switches; temperature-sensitive sensors; Possible examples include temperature-sensitive adhesives, dehydration improvers for polymer flocculants, polymer raw materials for tertiary oil recovery, adsorption components, release resin raw materials, antifogging agents, wall materials, and oil separators.

The temperature-sensitive polymer of the present invention has the effect that it can be set at any temperature at which it becomes insolubilized by heating, that is, by polymerizing it with the above-mentioned monomer.

thousand The present invention will be explained in more detail by way of examples.

Example 1 45.09 g of distilled water and 5.0 g of N-acryloylpyrrolidine were added to a 100 rnl four-tube round bottom flask while stirring under nitrogen gas flow. Then 0.50y of ammonium persulfate and 0.2y of sodium bisulfite. M was added and polymerized at 15 to 30°C for 4 hours.

The above aqueous polymer solution was placed in a test tube with an inner diameter of 15 mm, a standard thermometer was inserted into it, and the mixture was gradually heated in constant temperature water while stirring with the thermometer. It started to become cloudy at 48.5℃, 51
At ℃, the water in the thermometer became cloudy to the point that the silver bulb could no longer be seen. Even when this aqueous solution was further heated, it maintained a stable cloudy state. On the other hand, as the aqueous solution was cooled, it became transparent below the cloudy temperature.

Examples 2 to 28 Polymerization was carried out in exactly the same manner as in Example 1, except that the monomer combinations shown in Tables 1, 2, and 3 were used. However, in Examples 2, 3, 5, 16, 20 to 28, the amounts of ammonium persulfate and sodium bisulfite added were halved. Using the polymer aqueous solution obtained in this way,
The clouding onset temperature and the clouding temperature were measured in exactly the same manner as in Example 1, and the results are shown in Tables 1, 2, and 3. However, the cloudiness starting temperature is the temperature at which the cloudiness starts to occur due to heating.
The cloudy temperature is the temperature at which the mercury bulb on the thermometer becomes invisible due to cloudiness.

In all cases, the cloudy liquid became colorless and transparent upon cooling.

Example 29 In Example 1, ammonium persulfate and sodium bisulfite were added at 0.05f and 0.023! Polymerization was carried out in exactly the same manner as in Example 1, except that the following was added. When the white turbidity onset temperature and the white turbidity temperature were measured in the same manner as in Example 1, results of 55°C and 58°C were obtained.

Example 30 Polymerization was carried out in the same manner as in Example 1, except that 0.0 IP and 0.0046 g of ammonium persulfate and sodium hydrogen sulfite were added in Example 1. /piJ was measured, and results of 55°C and 58°C were obtained.

Example 31 The poly N-acryloylpyrrolidine aqueous solution obtained in Example 1 was diluted with distilled water and the clouding onset temperature was measured in the same manner as in Example 1. At 5.0% a, it was 51°C, 2. 9
The results were 52℃ for % and 59℃ for 0.3%.
It was.

Example 32 4.5 g of N-acryloylpyrrolidine and t-butyloxy(2-ethylhexano, ?? = 1-)io■ were added to 70% benzene under a nitrogen gas flow, and the mixture was heated to 40-65°C. The reaction was carried out for 10 hours.

The above benzene solution 1o- was collected and benzene was distilled off from it to obtain a film of N-'acryloylpyrrolidine 0.6f.

Distilled water was added thereto to dissolve N-acryloylpyrrolidine, and the temperature at which cloudiness started was measured in the same manner as in Example 1, and a result of 54°C was obtained.

Example 33 2 cc of ethanol was added to 23 cc of the aqueous solution of polyN-ac and lyloylpyrrolidine obtained in Example 1, and the temperature at which cloudiness started was measured, and a result of 80'C was obtained.

patent applicant Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] General formula (where R is hydrogen or a methyl group, and 1 is 4 to 1
is a positive integer of O. ) A temperature-sensitive polymer consisting of an unsaturated amide compound alone or a copolymer, or a copolymer with other copolymerizable monomers, which becomes insoluble in water by heating.