JPH06166863A - Thickener and method by using the same - Google Patents

Abstract

PURPOSE:To obtain a thickener whose viscosity reduction temperature can be changed by changing the constituent comonomer, by emulsifying an aqueous solution of a specified vinyl compound in an organic solvent in the presence of a hydrophobic surfactant and polymerizing the monomer to form an emulsion. CONSTITUTION:This invention thickener is a temperature-sensitive one for a water-based fluid and comprises a water-insoluble polymer emulsion obtained by emulsifying an aqueous solution of a vinyl compound which can give a thermoreversibly hydrophilic and hydrophobic polymer when homopolymerized or a mixture thereof with at most 10mol% other comonomers in an organic solvent in the presence of a hydrophobic surfactant and polymerizing the monomer mixture. Because this thickener comprises a water-in-oil emulsion and has a particle diameter of 10mum or below, desirably 3mum or below, it has the advantage of being rapidly and uniformly dispersed in a substance containing it. Examples of the hydrophobic surfactant include nonionic surfactants of an HLB of 3-6, and sorbitan monooleate is particularly desirable. The amount of the organic dispersion medium used is 20-50wt.% based on the emulsion to be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature-sensitive thickener for water-based fluids, and a method for transferring and printing solid matter using the thickener.

[0002]

BACKGROUND OF THE INVENTION Conventionally, as thickeners for aqueous fluids, polymer type thickeners such as hydroxyethyl cellulose, carboxymethyl cellulose, sodium alginate, guar gum and sodium polyacrylate and alkyl-modified polyether type are generally used. A thickener called associative thickener is used.

On the other hand, thickeners generally called heat-sensitive gelling agents such as polyalkylene oxides, polyvinyl methyl ethers, polyalkylene oxide-modified polysiloxanes, etc. are also known as proposed in JP-A-57-10665. ing.

On the other hand, a water-in-oil type polymer emulsion is known to be used as a raw material for paper processing agents, paints, and lubricants for the propulsion method.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have found that a polymer represented by N-isopropylacrylamide is a water-in-oil type polymer containing a vinyl compound which is a hydrophilic-hydrophobic thermoreversible polymer as a polymer component. When the emulsion is used as a thickener, it is found that the viscosity is rapidly reduced at a certain temperature or more, and a useful method of using the emulsion is found, and the present invention is proposed.

[0006]

Means for Solving the Problems The present invention includes (1) 10% by mole or less of a vinyl compound whose homopolymer is a hydrophilic-hydrophobic thermoreversible polymer or other copolymerizable monomer. An emulsion of a water-in-oil type polymer emulsion obtained by emulsifying an aqueous solution of a mixture of and with an organic solvent in the presence of a hydrophobic surfactant and then increasing the temperature sensitivity for an aqueous fluid. Sticky,

(2) The water-in-oil polymer emulsion contains 10 to 50% by weight of polymer, 20 to 50% by weight of organic solvent, and HLB 3 to 6 of hydrophobic surfactant 0. 5 to 5% by weight, average particle size 1
The thickener according to (1), which has a thickness of 0 μm or less,

(3) The thickener according to (1), wherein the homopolymer is a hydrophilic-hydrophobic thermoreversible polymer vinyl compound containing N-isopropylacrylamide alone or N-isopropylamide.

(4) The thickener according to (1), wherein the other copolymerizable monomer contains a crosslinking agent,

(5) After the mixture containing the thickener described in (1) is transferred to the aqueous fluid containing the solid, the solid is separated from the mixture by raising the temperature to the phase transition temperature or higher. A method of transferring a solid product using the thickener according to (1),

(6) It is characterized by facilitating the removal of the surplus mixture by printing the mixture obtained by adding the thickening agent described in (1) to the printing paste to a phase transition temperature or higher. ) A printing method using the thickener described above,

(7) An aqueous system in which a hydrophilic surfactant having an HLB of 10 or more is added to the water-in-oil type polymer emulsion described in (1) in an amount of 0.001 to 5% by weight based on the water-in-oil type polymer emulsion. A temperature-sensitive thickener for fluids,

(8) An aqueous system in which the water-in-oil type polymer emulsion described in (1) contains 0.001 to 5 parts by weight of a hydrophilic surfactant having an HLB of 10 or more relative to the water-in-oil type polymer emulsion. A temperature-sensitive thickener for fluids.

[0014]

The aqueous fluid of the present invention is typically various latex emulsions and aqueous dispersions used as raw materials for paper processing agents, paints, adhesives and the like.

It also includes an aqueous dispersion of bentonite used for civil engineering and muddy water.

Such a water-based fluid is appropriately thickened and used for convenience of use.

In the present invention, a so-called reverse-phase polymer emulsion of water-in-oil type is used as a thickening agent in this case in an apparent weight of about 0.001 to 5% by weight based on the additive. .

Since the thickener of the present invention uses a water-in-oil emulsion, it has a small particle size of 10 μm or less, preferably 3 μm or less, and has the advantage of being rapidly homogenized in the additive.

Next, the water-in-oil type polymer emulsion of the present invention will be described.

In this water-in-oil type polymer emulsion, a homopolymer thereof is a hydrophilic-hydrophobic thermoreversible polymer, a vinyl compound alone, or a mixture of the vinyl compound and another copolymerizable monomer. It is obtained by emulsifying in an organic solvent in the presence of a surface active agent and then polymerizing it.

As the vinyl compound whose homopolymer is a hydrophilic-hydrophobic thermoreversible polymer, an acrylamide vinyl compound whose homopolymer is a hydrophilic-hydrophobic thermoreversible polymer is used. And one or more of them can be used.

These specifically mean N-ethyl (meth) acrylamide [N-ethylacrylamide and / or N-ethylmethacrylamide. The same shall apply hereinafter], N-n-propyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-cyclopropyl (meth) acrylamide, N-methoxypropyl (meth) acrylamide, N-ethoxypropyl (meth) acrylamide And N-mono (alkoxy) alkyl-substituted (meth) acrylamides such as N-isopropoxypropyl (meth) acrylamide, N-ethoxyethyl (meth) acrylamide and N-methoxyethyl (meth) acrylamide.

These alkyl groups include straight chain alkyl groups, branched alkyl groups and alicyclic alkyl groups, but the number of carbon atoms is preferably 2-8, preferably 2-6.

When it is 1 or less, the homopolymer does not exhibit hydrophilic-hydrophobic thermoreversibility, and when it is 9 or more, the water solubility becomes too low, and the polymerization cannot be carried out at an economical concentration.

When an alkoxy group is included, the oxygen atom has hydrophilicity, so that even a substituent having a large number of carbon atoms is water-soluble and a relatively high concentration of polymerization is possible.

Specific examples of other monomers include N, N
-Diethyl (meth) acrylamide, N-methyl-N-
Ethyl (meth) acrylamide, N-methyl-N-n-
Propyl (meth) acrylamide, N-methyl-N-isopropyl (meth) acrylamide, N- (2,2-
Mention may be made of N- (alkoxy) alkyl-N-alkyl-substituted (meth) acrylamides such as dimethoxyethyl) -N-methylacrylamide.

These alkyl groups include a straight chain alkyl group and a branched alkyl group, and an alkyl group or an alkoxyalkyl group having 2 to 5 carbon atoms, preferably 2 to 3 carbon atoms is desirable.

Examples of other monomers include N-cyclic disubstituted acrylamides such as N-acryloylpyrrolidine and N-acryloylpiperidine.

Of these, representative ones are N-isopropylacrylamide, N, N-diethylacrylamide, N
-Acryloylpyrrolidine and the like.

Other copolymerizable monomers include
(Meth) acrylamide, (meth) acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, vinylsulfonic acid, styrenesulfonic acid, itaconic acid, maleic acid, fumaric acid, arylsulfonic acid and salts thereof,
Water-soluble vinyl monomers such as dimethylaminoethyl (meth) acrylate and methyl vinyl ether, and water-insoluble vinyl monomers such as various (meth) acrylic acid esters and styrene are typical, and their homopolymers are hydrophilic. The content may be 10 mol% or less with respect to the vinyl compound which is a polymer-hydrophobic thermoreversible polymer.

The other copolymerizable monomer may contain a crosslinking agent in an amount of 0.005 to 5% by weight, preferably 0.01 to 1% by weight, based on the water-soluble vinyl monomer. .

When a crosslinking agent is included, the polymer becomes water-swellable. In addition, when a cross-linking agent is included, a phase transition phenomenon occurs with a small particle size, and reversibility is also excellent.

As the cross-linking agent, one which can be copolymerized with a water-soluble vinyl monomer is used. Specific examples thereof include N,
Examples thereof include N'-methylenebisacrylamide, diallyl phthalate, divinylbenzene, (poly) ethylene glycol di (meth) acrylate and the like.

As the hydrophobic surfactant, nonionic surfactants such as sorbitan fatty acid ester of HLB 3 to 6, fatty acid ester of polyethylene glycol, ethylene oxide adduct of higher alcohol and glycerin fatty acid ester are used. Medium sorbitan monooleate is preferred.

The amount of addition was 0.
It is 5 to 5% by weight, preferably 1 to 3% by weight. 0.5
If it is less than wt%, the dispersibility of the emulsion is insufficient,
If it exceeds 5% by weight, a large amount of a hydrophilic surfactant is required when inversion of the obtained polymer into an oil-in-water type is not preferred.

As the organic dispersion medium, aliphatic, alicyclic and aromatic hydrocarbons may be used alone or in combination.

Specific examples include n-pentane, n-hexane, n-heptane, n-octane, 2,3-dimethylbutane, isooctane, cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, ligroin, toluene, benzene, Examples include xylene, mineral oil and kerosene.

The amount of addition thereof is 20 to 50% by weight, preferably 20 to 30% by weight, based on the obtained emulsion. If it is less than 20% by weight, the stability of the emulsion becomes poor, and if it exceeds 50% by weight, the polymer is added. Net content decreases, and the amount of surfactant added increases.

As the polymerization method, emulsion radical polymerization may be carried out in accordance with the method described in JP-A-63-90537 already filed by the present applicant.

For example, the above raw materials are added to an organic dispersion medium containing a hydrophobic surfactant with an aqueous solution containing a water-soluble vinyl monomer and other necessary monomers, and a known emulsification method, preferably a homogenizer is used. Emulsify by.

Next, while decompressing the emulsion emulsified by the above method, deoxidation harmful to polymerization is carried out under reduced pressure or normal pressure.

Usually, degassing is carried out by N ₂ purge degassing method, and radical polymerization catalyst is added to carry out polymerization. As the polymerization temperature,
Polymerization is carried out at a temperature lower than the phase transition temperature of the raw material monomer (the temperature at which the polymer becomes water-insoluble).

For example, the phase transition temperature is N-ethyl acrylamide 72 ° C., N-ethyl methacrylamide 50 ° C., N
-Isopropylacrylamide 31 ° C, N-isopropylmethacrylamide 44 ° C, N-acryloylpyrrolidine 56 ° C, N-acryloylpiperidine 6 ° C. If the polymerization is carried out at the phase transition temperature or higher, a good emulsion cannot be obtained.

As the radical polymerization catalyst, a general radical polymerization catalyst is used, and specific examples thereof include redox type, azo type, organic and inorganic peroxide type.

The polymerization time is usually 3 to 6 hours. The average particle size of the obtained polymer is 10 μm or less, preferably 3 μm.
m or less.

The resulting emulsion polymer is, after polymerization,
It is also possible to distill water out by heating under reduced pressure and increase the polymer concentration.

Next, when the water-in-oil type polymer emulsion is used as a thickener for the water-based fluid, the emulsion is phase-shifted from the water-in-oil type to the oil-in-water type, so that the apparent weight of the emulsion becomes hydrophilic. 0.001 to 5% by weight of a surface active agent
Use to some extent.

The hydrophilic surfactant may be added to the water-in-oil emulsion during the production thereof, or may be added to the water-in-oil polymer emulsion or the aqueous fluid or both in use. May be.

As the hydrophilic surfactant, nonionic surfactants such as polyoxyethylene alkyl ether and polyoxyethylene alkylphenol ether are mainly used. Among these, polyoxyethylene lauryl ether having HLB of 10 or more and polyoxyethylene Ethylene nonylphenol ether is preferred.

As will be described in the examples below, the thickener of the present invention sharply decreases in viscosity above a certain temperature (this temperature is called a phase transition temperature) depending on the copolymerization component.

By utilizing this phenomenon, the following useful applications can be developed, for example. For example,

(1) For example, as shown in FIG. 2, a solid substance 1 (stone or metal) having no fluidity is mixed with an aqueous fluid containing the thickener 2 of the present invention to transfer it through a pipe 3 or the like. Is possible.

When it is desired to take out the solid product, the viscosity can be reduced and the product can be easily separated (settled) by heating 6 to a predetermined temperature or higher. Moreover, the paste can be used repeatedly 5.

Contamination of wastewater can be reduced by repeated use.

(2) When it is used as a sizing agent in textile dyeing, the viscosity sharply decreases above a certain temperature, so that it can be easily removed from the dyed surface.

An example will be described below.

[0057]

Example 1 (A) Sorbitan monooleate 20 in 180 g of hexane
dissolve g. Meanwhile, N-isopropylacrylamide (NIPAM) 90 g, methylenebisacrylamide 0.018 g, and ammonium persulfate 0.009 g were added to water 5
It is dissolved in 10 g and mixed with the previously dissolved hexane solution with stirring to emulsify.

After deoxidizing the emulsion by introducing nitrogen, the temperature was kept at 20 ° C. and an aqueous sodium hydrogen sulfite solution was added dropwise to polymerize the emulsion.

After the polymerization, 25 g of polyoxyethylene lauryl ether (HLB12) was added.

The obtained emulsion is milky white and has a size of 20 to 20.
It has a viscosity of 30 cps (B type viscometer 30 rpm). The average particle size was 1.5 μm.

(B) NIPAM 90g is replaced with NI
PAM was produced in the same manner as in A except that 87 g and sodium acrylate 3 g were used.

(C) NIPAM 90 g is replaced with NI
It was produced in the same manner as in A, except that PAM was 85 g and sodium acrylate was 5 g.

(D) (Comparative Example 1) The same procedure as in A was carried out except that 90 g of NIPAM was changed to 90 g of acrylamide.

(E) (Comparative Example 2) NIPAM (50 g) and methylenebisacrylamide (0.01 g) were dissolved in distilled water (450 g) and purged with N ₂ for 30 minutes in a 1 l heat-insulated container.
Cool and maintain temperature at 0 ° C.

To this aqueous solution, 0.025 g of azobis (2-amidinopropane) hydrochloride and 3 parts of methanol were added, and ammonium persulfate 0.000 was added as an initiator.
4 parts, 0.003 parts ferrous ammonium sulfate were added,
The reaction was completed in about 5 hours by performing adiabatic polymerization at a reaction starting temperature of 0 ° C.

The polymer gel obtained was placed in hot water at 95 ° C. for 9 minutes.
After heat treatment for 0 minutes, the hydrous polymer gel was roughly pulverized and further made into a polymer gel having a particle size of 3 mm by a meat chopper. This was placed in a dryer at 70 ° C., dried for 2 hours and then crushed by a crusher to produce a polymer dry powder having a particle size of 0.15 to 1.0 mm.

[0067]

Example 2 90 g of N-isopropylacrylamide of (A) of Example 1 was mixed with 9% of N, N-diethylacrylamide
Polymerize in the same manner with 0 g, add a surfactant,
45 cps (B type viscometer 30 rpm), average particle size 1.8
A μm emulsion (F) was obtained.

[0068]

[Table 1]

Water-in-oil emulsion 4 of (A) to (F)
0 g was added to 60 g of water with stirring to thicken.
(E) 4.4 g was added to 95.6 g of water with stirring, and the mixture was stirred for 1 hour.

This thickened product was temperature-controlled in the range of 15 ° C. to 90 ° C., and its viscosity was continuously measured with a B type viscometer at 30 rpm. The results are shown in Fig. 1.

In (A), a remarkable change in viscosity occurs in the range of 32 to 33 ° C. (B) is 50-55 ° C, (C) is 70-
Changes occur at 80 ° C. The viscosity of (D) gradually decreases in the range of 15 to 90 ° C., but does not change significantly.
(E) has a small absolute value although its viscosity changes in the range of 32 to 33 ° C., and has little effect as a thickener. In (F), a remarkable change in viscosity occurs in the range of 36 to 38 ° C.

Any change in viscosity is reversible.

[0073]

[Table 2]

[0074]

[0075]

[Example 3] Example of printing paste agent Test method: 12,000 cps (B
Type viscometer, 25 ° C, 30 rpm)
A polyester cloth (polyester satin 78.6 g / m ² ) was printed with the color paste prepared by the following formulation, dried at 170 ° C. for 5 minutes, and fixed to obtain a 10 cm × 10 cm sample piece. Determine the absolute dry weight of the printed color paste, then soak the sample piece in a cold water bath at 20 ° C for 5 minutes while shaking, and blow dry the dyed sample piece to obtain the absolute dry weight of the residual color paste. The desizing rate was calculated from the following formula.

[0076]

[Equation 1]

As the original paste, the one shown in Table 3 was used.

[0078]

[Table 3]

The color paste prescription is 60 parts of original paste, disperse dye (Miketone Polyester Blue TGSF, Mitsui Toatsu Dye Co., Ltd.).
1 part), Na ₂ CO ₃ 1 part, malic acid 0.5 part, water 3
The desizing rate was measured as 7.5 parts, 100 parts in total (4th part).
table).

[0080]

[Table 4]

There was no particular visual difference in the color forming property among the four types, but a slight bleeding was observed in the crosslinked polyacrylic acid salt.

Desizing properties of A and C of the present invention are excellent,
Economical effect is high because the viscosity is good.

[0083]

The viscosity reduction temperature can be changed by changing the copolymerization component, which is useful for various industrial applications.

[Brief description of drawings]

FIG. 1 is a diagram showing changes in temperature and viscosity of various samples in Examples and Comparative Examples.

FIG. 2 is an explanatory view of a method for separating a solid material from an aqueous fluid containing the solid material.

[Explanation of symbols]

 1 Solid matter 2 Glue 3 Transfer tube 4 Decreased glue 5 Repeated use 6 Heating

Claims (8)

[Claims] 1. An aqueous solution of a mixture of a vinyl compound whose homopolymer is a hydrophilic-hydrophobic thermoreversible polymer or 10 mol% or less of another copolymerizable monomer is used as a hydrophobic surfactant. A temperature-sensitive thickener for water-based fluids, which comprises a water-in-oil type polymer emulsion obtained by emulsifying it in an organic solvent in the presence of the above. 2. A water-in-oil polymer emulsion comprising 10 to 50% by weight of polymer, 20 to 50% by weight of organic solvent and 0.5 to 0.5 of a hydrophobic surfactant of HLB 3 to 6, based on the total weight of the emulsion. ~ 5 wt%, average particle size 10
The thickener according to claim 1, which has a thickness of not more than μm. 3. The thickener according to claim 1, wherein the vinyl compound whose homopolymer is a hydrophilic-hydrophobic thermoreversible polymer contains N-isopropylacrylamide alone or N-isopropylamide. 4. The thickener according to claim 1, wherein the other copolymerizable monomer contains a crosslinking agent. 5. An aqueous fluid containing a solid product according to claim 1.
The transfer of a solid product using the thickener according to claim 1, wherein the solid product is separated from the mixture by raising the temperature to a phase transition temperature or higher after transferring the mixture containing the thickener. Method. 6. A printing paste comprising a thickening agent according to claim 1 added to the mixture, after printing, the mixture is heated to a phase transition temperature or higher to facilitate removal of the excess mixture. A printing method using the thickening agent described. 7. A water-based fluid obtained by adding 0.001 to 5% by weight of a hydrophilic surfactant having an HLB of 10 or more to the water-in-oil polymer emulsion according to claim 1. A temperature-sensitive thickener for the body. 8. A water-based fluid wherein the water-in-oil polymer emulsion according to claim 1 contains a hydrophilic surfactant having an HLB of 10 or more in an amount of 0.001 to 5 parts by weight based on the water-in-oil polymer emulsion. A temperature-sensitive thickener for the body.