JP2709710B2 - Radical curable water-soluble polymer - Google Patents

Description

The present invention relates to a novel and useful water-soluble polymer containing an ethylenically unsaturated double bond, and more particularly to a water-soluble polymer cured by a redox initiator or a light irradiation method. The present invention relates to a radical-curable water-soluble polymer which can be a main component or a cross-linking agent component such as a water stopping agent, an enzyme fixing agent, a binder and an image forming material.

[Conventional technology]

Some of the radically curable water-soluble polymers are
In combination with a water-soluble monomer and a radical generator, it is used in the fields of various binders, soil hardeners, waterstopping agents, enzyme fixing agents, and the like.

In addition, oil-based radical-curable compositions have been widely used in various coating agents, image forming materials, inks, etc. In view of this, in recent years, conversion to an aqueous composition has been desired.

In the radical curable composition, in order to form a network of molecules, it is necessary to blend a polyfunctional compound having two or more ethylenically unsaturated double bonds in one molecule.

As such a polyfunctional compound, a low-molecular compound called a cross-linking agent is often often used, but a polyfunctional oligomer having a molecular weight of several thousand or a polyfunctional polymer having a higher molecular weight is particularly useful. That is, compared to the low molecular weight crosslinking agent, a polyfunctional compound having a large molecular weight is
The film itself has characteristics such as film forming property and high curing speed.

However, there are surprisingly few polyfunctional water-soluble polymers that are industrially practically used. Specifically, polyethylene glycol diacrylates and polyethylene glycol dimethacrylates are commercially available, and are used as a main component of immobilizing enzymes and water-stopping agents for infiltration into sewer pipes. Not used for image formation. Also, the price is expensive.

Polyvinyl alcohol (PVA) in which various photosensitive groups are introduced is well known, but most of them are photodimerized photosensitive groups, and are not of the type that performs a normal radical chain reaction. Various introduction of acrylic group, methacrylic group, etc. into PVA is also known, but it is necessary to carry out the introduction reaction in an organic solvent such as DMF, and the production cost is not low.
Few are practically used.

[Problems to be solved by the invention]

As described above, a few water-soluble polyfunctional polymers have been known, but the double bond introduction reaction is carried out in an organic solvent, despite being used after being dissolved in water. The film cannot be produced in any way, or has poor physical properties as a film because it does not have a sufficient molecular weight.

The present inventors have eagerly aimed at solving the above problems by synthesizing a polymer having a wide range of arbitrary molecular weights and a sufficient double bond content by a reaction in an aqueous medium at a relatively low cost. The present inventors have conducted studies and completed the present invention.

[Means for solving the problem]

That is, the present invention relates to 99 to 70 mol% of acrylamide or methacrylamide in an aqueous medium and dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, diethylaminopropyl (meth) acrylate, Tertiary copolymer salt formed by reacting 1 to 30 mol% of a cationic vinyl monomer having a tertiary amino group selected from the group consisting of dimethylaminopropyl (meth) acrylamide and diethylaminopropyl (meth) acrylamide Molecular weight obtained by reacting glycidyl group-containing vinyl monomer with amino group in aqueous medium
Five to one million radical-curable water-soluble polymers.

The main chain of the polymer of the present invention is formed by a copolymer of acrylamide or methacrylamide (hereinafter abbreviated as (meth) acrylamide) and a cationic vinyl monomer having a tertiary amino group. When a polymer containing (meth) acrylamide as a main component is a crosslinked gel, a gel having good mechanical strength is formed due to the hydrogen bonding ability of the amide group. When a polymer aqueous solution is applied, dried, and cured, a strong film is formed.

Examples of the cationic vinyl monomer having a tertiary amino group include dimethylaminoethyl (meth) acrylate,
Examples thereof include diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, diethylaminopropyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide, and diethylaminopropyl (meth) acrylamide.

The copolymerization ratio of the cationic vinyl monomer and (meth) acrylamide governs the double bond content of the final product.
The cationic vinyl monomer unit in the copolymer has 1 to 30 units.
Mol%, preferably 2 to 10 mol%. At the time of polymerization, another vinyl monomer copolymerizable with these monomers may be added and used.

The copolymerization reaction is carried out by a method using an appropriate initiator in an aqueous medium or by a light irradiation method. The aqueous medium is
Usually, it is water, but depending on the purpose of use of the product, even an aqueous solution containing an organic solvent such as alcohol, which can be mixed with water, can be used in a range in which the monomer and the produced polymer are soluble.

A polymer having a desired molecular weight can be obtained by selecting the type and amount of the initiator used for the polymerization and, if necessary, using a chain transfer agent. Acrylamide easily gives a high molecular weight polymer by polymerization in water, but as a polyfunctional polymer used for a radical curing reaction, it has an appropriate molecular weight of several thousand to tens of thousands in general called an oligomer in terms of workability and the like. Things are often desirable. In this case, a polymer having a desired molecular weight can be obtained by performing polymerization using a chain transfer agent such as thioglycolic acid or β-mercaptopropionic acid.

It is desirable that the concentration of the monomer in the polymerization is as high as 5% or more from the viewpoint of productivity and the cost of transporting the product, but it becomes difficult to stir due to an increase in the viscosity of the polymer solution, and it becomes difficult to remove the heat of polymerization. Therefore, the content is limited to 5 to 50% by weight, preferably about 10 to 30% by weight.

Next, in order to introduce a double bond into the copolymer, a reaction with a glycidyl group-containing vinyl monomer is performed. In this reaction, the aqueous copolymer solution can be used as it is.

As the glycidyl group-containing vinyl monomer, for example,
Glycidyl (meth) acrylate, N-glycidyl (meth) acrylamide, or the like can be used.

The glycidyl group referred to here is Which includes those in which a part of the hydrogen is substituted by a lower alkyl group or the like.

The amount of the glycidyl group-containing vinyl monomer to be used is determined based on the amino group in the copolymer, and is usually in the range of 0.5 to 5 moles per mole of the amino group.

The content of the ethylenically unsaturated double bond in the radical-curable water-soluble polymer of the present invention is determined depending on the content of the copolymerized cationic vinyl monomer and the amount of the glycidyl group-containing vinyl monomer, and is selected according to the purpose of use. But
As a double bond mole number per unit polymer weight, 0.2 to 1.5
About meq / g is appropriate.

The glycidyl group-containing vinyl monomer is introduced into the copolymer by a reaction between an amino group of a cationic vinyl monomer having a tertiary amino group in the copolymer and a glycidyl group. It is necessary to keep the cationic vinyl monomer component in a salt form by adding hydrochloric acid or the like.

The reaction is usually carried out at a temperature of 40 to 100 ° C. with stirring for several hours. The pH of the solution is set to 3 because significant acidity or alkalinity may cause hydrolysis of the amide group and ester group.
A range of ~ 10 is good.

The molecular weight of the polymer of the present invention depends on the molecular weight of the copolymer which is substantially the main chain, and can be arbitrarily selected within a wide range according to the purpose. For example, when injected into soil as a water-stopping agent, a lower viscosity is suitable for improving permeability into the soil, and is in a range of about 500 to 50,000. On the other hand, when a dried and cured film is formed, a film having a molecular weight of about 10,000 to 100,000 is desirable in order to obtain good film properties. Further, depending on the application, it can be used up to a molecular weight of about 1,000,000. However, if the molecular weight is too large, the workability at the time of mixing or coating with other monomer components is deteriorated.

The radical-curable polymer of the present invention can be purified and used by reprecipitation with methanol for special uses, but for most uses, the reaction with the glycidyl group-containing vinyl monomer is followed by the reaction. Other components such as a radical generator can be directly added to the liquid and used for the curing reaction.

This radical-curable polymer can be cured with only its aqueous solution and a radical-generating agent, for example, a redox initiator, but can be more easily cured by being mixed with another water-soluble vinyl monomer. .

The monomer used for this purpose may be any monomer that can be mixed with the radical-curable polymer of the present invention dissolved in an aqueous medium, and specifically includes (meth) acrylic acid and a salt thereof, (meth) acrylamide, hydroxy Examples thereof include N-vinyl-substituted nitrogen-containing heterocyclic compounds such as ethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and N-vinylpyrrolidone. Also, N, N
-Dialkylaminoethyl (meth) acrylate and its tertiary salt and quaternary compound, and N, N-dialkylaminopropyl (meth) acrylamide and its tertiary salt and quaternary compound can also be used. Naturally, these monomers can be used in combination of several types if they can enhance the function of the cured product.

As a radical generation source of the curing reaction, various compounds that generate a radical by heat, light, an oxidation-reduction reaction, or the like are used. When heat is used, heat energy and time are required to raise the entire system to be cured to a certain temperature, and the advantage of the radical curing reaction is often lost, but in special cases 2,2 ' -Can be cured using a thermal initiator such as azobis (2-amidinopropane) hydrochloride or peracetic acid.

Curing by light irradiation can be advantageously used for curing a dried film of the composition containing the polymer of the present invention, and also for curing in an aqueous solution. In this case, various compounds generally called a photoinitiator or a sensitizer are used. Many benzoin ethers and benzophenones known as photoinitiators are hardly soluble in water, but can be dissolved and used to some extent in the presence of an organic substance such as the polymer of the present invention. In addition, water-soluble photoinitiators such as anthraquinone-β-sulfonate and 4-carboxybenzophenone can be advantageously used.

An oxidation-reduction system, that is, a redox initiator can be used mainly when gelation is performed in an aqueous solution. Various known redox systems, for example, a combination of various reducing agents such as persulfate and sodium bisulfite, ferrous salt, sodium formaldehyde sulfoxylate, or a combination of hydroperoxide and amine can be used. .

The radical-curable polymer of the present invention can be used by mixing with other general-purpose water-soluble resins, for example, polyvinyl alcohol, polyacrylic acid, polyvinylpyrrolidone, carboxymethyl cellulose, gelatin, and the like, if necessary. Further, it can be used by mixing with a water-dispersible resin such as a polyvinyl acetate resin emulsion or a styrene-butadiene copolymer emulsion.

〔The invention's effect〕

The radical-curable polymer of the present invention can have a desired structure from a wide range of molecular weight and double bond content according to the intended use, and is useful as a component of the curable composition for a wide range of applications. It is.

In addition, as described above, all of the production is performed in an aqueous medium, and can be used without isolation as it is, which is economically advantageous.
There is no worry about air pollution.

This curable polymer is used by mixing monomers and other various additives according to the purpose in addition to the radical generating source, but it is used for stabilization by hardening the soil, penetration of sewer pipes, etc. There is hardening based on formation of hydrogel, such as water stoppage and immobilization of enzymes and cells. Examples of the scene where the film is cured as a dry film include a coating of paper, a wooden product, a metal plate, and the like, a printing ink, a photoresist, and the like. In addition, it is useful as a component for various binder adhesives and pastes.

(Experimental example)

In the following experimental examples, the percentages of the concentration and the amount of addition relate to weight unless otherwise specified.

Examples 1 to 6 288 g of a 50% aqueous solution of commercially available acrylamide (AAm), 16 g of dimethylaminopropylmethacrylamide (DMAPMA) and 1.6 g of 2,2'-azobis (2-amidinopropane) hydrochloride
g was dissolved in 1 pure water, the pH of the solution was adjusted to 3.5 with dilute hydrochloric acid, and then pure water was further added to adjust the total amount to 1,600 g.

Three monomer solutions were prepared, and the amount of β-mercaptopropionic acid (MPA) shown in Table 1 was added to each of them. The mixture was transferred to a UV reaction vessel equipped with a 100 W high-pressure mercury lamp (UVL-100HA manufactured by Riko Kagaku Sangyo Co., Ltd.) having a capacity of 1,800 ml, and subjected to enzyme replacement by nitrogen aeration, followed by UV irradiation for 6 hours to polymerize.

After the reaction, the viscosity of the reaction solution (solid content: 10%) was measured with a B-type viscometer (using a BL adapter). Unreacted monomers were quantified by high performance liquid chromatography to calculate the conversion. The molecular weight of the produced polymer was determined by the GPC method and calculated as a value in terms of polyethylene oxide. Table 1 shows the results.

Next, 500 g of each of the above polymerization solutions was taken, and the reaction was carried out while changing the amount of reagent glycidyl methacrylate (GMA) as shown in Table 2. Before the addition of GMA, the pH of the polymerization solution was adjusted to about 7.5 with an aqueous sodium hydroxide solution. The reaction with GMA was performed at 70 ° C. for 3 hours. After leaving one reaction solution, colloid titration was performed to quantify amino groups in the polymer. Table 2 shows the results. The colloid titration value is the number of moles of amino groups per unit weight of polymer (meq /
g). The titration results at pH 4 indicate all amino groups in the polymer, and the values at pH 11 indicate amino groups quaternized by GMA. Thus, the ratio of the value at pH 11 to the value at pH 4 indicates the percentage of amino groups derived from the cationic vinyl monomer that have reacted with GMA. The value at pH 11 is the double bond content in the polymer.

Examples 7 to 12 Acrylamide (50% aqueous solution) and dimethylaminoethyl methacrylate (DMAEMA) were mixed with 90/10 to 7 as shown in Table 3.
After mixing at a ratio of 0/30 (weight) and adjusting the pH to 2.5 with dilute sulfuric acid, 2,2'-azobis (2-amidinopropane) hydrochloride
50 ml of a liquid containing 0.1% was prepared. The total monomer concentration was set to 5% only when the amount of the chain transfer agent was small, and 20 to 25 for the others.
%.

The amount of mercaptoacetic acid (MA
C) was added as a chain transfer agent, and after aeration with nitrogen in a 100 ml test tube, polymerization was carried out for 2 hours by immersion in a water bath at 80 ° C.

After the polymerization, the conversion of the monomer and the molecular weight of the produced polymer were determined in the same manner as in Example 1.

Next, the pH of this polymerization solution was adjusted to 7.5 with sodium hydroxide solution, and a 2-fold molar amount of GMA was added per amino group contained, followed by stirring at 50 ° C. for 4 hours. After standing overnight at room temperature, amino groups were quantified by colloid titration. From the ratio of the colloid titration values of pH 11 and 4, it is considered that about 80% of the amino groups reacted with GMA.
Molecular weights of about 2,000 to 1 million were obtained.

Examples 13 to 16 and Comparative Example 1 In order to test the performance as a water stopping agent or a soil stabilizer,
Using a curable composition comprising the curable polymer of the present application, sodium acrylate and a redox initiator, sand was cured and a compression test of the cured product (sand gel) was performed.

First, the curable polymer solutions of Examples 2 to 5 and an aqueous solution of sodium acrylate (AA-Na) were mixed in the proportions shown in Table 4, and the reducing agent triethylamine (TEA) and pure water were added thereto to adjust the total amount. It was 19.2 ml.

On the other hand, a 25 mmφ × 100 mmH PVC pipe whose bottom was sealed with a rubber stopper and in which 70 g of Toyoura standard sand was put was prepared.

Further, 0.8 ml of a 25% ammonium persulfate (APS) solution was quickly mixed with 19.2 ml of the above-mentioned curing agent composition, and the mixture was transferred to a polyvinyl chloride pipe and permeated into sand. The whole cured in 1-2 minutes. After curing overnight, extrude the sand gel produced with a rod slightly smaller in diameter than the PVC pipe and use Toyo Baldwin's Tensilon at 5 mm / min.
The compression test was performed at the following speed.

The effective component (monomer + curable polymer) in a total of 20 ml of the gelling agent is about 10%. The ratio of monomer / curable polymer therein is 50/50 (weight) (however, GMA in the curable polymer is calculated on the monomer side).

For comparison, NK ester 23G [polyethylene glycol (# 1000) dimethacrylate, double bond content
1.8 meq / g, manufactured by Shin-Nakamura Chemical Co., Ltd.].

Table 4 shows the results of the compression test. From this, expensive polyethylene glycol dimethacrylate (NK ester 23
It can be seen that a sand gel having a strength equivalent to or better than that obtained by using G) can be obtained by the curable polymer of the present invention. Although the double bond content of the polymers of Examples 2 to 4 is lower than that of Comparative Example 1 (NK ester 23G),
It is considered that the mechanical strength is not inferior due to the effect of secondary cross-linking due to hydrogen bonding of the amide group and the molecular weight. In addition, the gelling agent composition of Comparative Example 1 is similar to a commercially available one as a sewer pipe penetration waterproofing agent.

Examples 17 to 19 and Comparative Examples 2 to 4 The photocuring properties of the dried film of the polymer of the present invention were examined as follows.

The polymer solution of Example 11 (effective content: 21.3%), hydroxyethyl methacrylate (HEMA) and 27% PVA solution (polymerization degree: 500, saponification degree: 86.5%) were mixed, and a photoinitiator benzyl ketal (BK) was added. Thus, a solution having the composition shown in Table 5 was prepared. This was applied to a grained aluminum plate with a spinner and dried at 80 ° C for 2 hours (film thickness of about 20).
μ).

This dried film was exposed stepwise at a position 15 cm below a 500 W ultra-high pressure mercury lamp, and then developed with ion-exchanged water. Also,
For comparison, NK ester 23G and NK ester A-200
[Polyethylene glycol (# 200) diacrylate,
Double bond content 6.5 meq / g, manufactured by Shin-Nakamura Chemical Co., Ltd.]. From the pattern obtained in the stepwise exposure, the time at which curing started and the time at which it was completed (the time at which there was no longer any change after further irradiation) were recorded and are shown in Table 5.

The polymer of the present invention has a high curing rate despite a low double bond content. In addition, unless the polyethylene glycol-based curable polymer is used in combination with another resin such as PVA, a good dry film is not formed.

Claims (1)

(57) [Claims] 1. An aqueous medium comprising 99 to 70 mol% of acrylamide or methacrylamide and dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, diethylaminopropyl (meth) acrylate, dimethyl Tertiary amino of a salt of a copolymer obtained by reacting 1 to 30 mol% of a cationic vinyl monomer having a tertiary amino group selected from the group consisting of aminopropyl (meth) acrylamide and diethylaminopropyl (meth) acrylamide A radical-curable water-soluble polymer having a molecular weight of 500 to 1,000,000, obtained by reacting a glycidyl group-containing vinyl monomer with a vinyl group in an aqueous medium.