JPS62270608A - Water-soluble acrylic copolymer - Google Patents

Abstract

PURPOSE:To obtain the title copolymer excellent in salt resistance and ion resistance and useful for pastes, latices, etc., by copolymerizing (meth)acrylic acid with a specified compound in the presence of, optionally, a crosslinking agent. CONSTITUTION:A mixture comprising 90.0-98.5wt% (meth)acrylic acid, 10.0-1.5wt% compound of formula I (wherein Y is a group of formula II or III, R is H or CH3, Y is a group of formula IV, R1 is a 6-30C alkyl or alkylphenyl, l, m and n are in the range of 2<l+m+n<100, provided that m or n is equal to or greater than 1), e.g., allyl polyoxyethylene, and, optionally, 10wt% or below other vinyl monomers copolymerizable therewith (e.g., ethyl acrylate) in the presence of, optionally, 5wt% or below, based on the mixture, crosslinking agent (e.g., allylpentaerythritol) which is a polyalcohol polyalkenyl ether having at least two alkenyl ether groups per molecule of a 2C or higher alcohol having at least two hydroxyl groups.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] This invention relates to a water-soluble acrylic copolymer, specifically a paste,
As a thickener for various aqueous solutions used in latex, raw materials for ceramic molding, cosmetics, pharmaceuticals, etc., as a water-breathing material for sanitary products, as a water-retaining material for agricultural and horticultural purposes, and as wall materials, and as a fire protection agent during firefighting. This invention relates to a water-soluble acrylic copolymer used as a water-absorbing agent or water-retaining agent useful for diffusion prevention and the like.

[Conventional technology]

Among homopolymers of acrylic acid and methacrylic acid and their salts, particularly those with a high degree of polymerization or slightly crosslinked polymers exhibit high viscosity in water due to the repulsion of their molecules by high-density anions. Therefore, these polymerized products are utilized in many ways as thickeners or water-absorbing polymers by taking advantage of their warm properties.

However, this polymer has the disadvantage that when it encounters opposing ions, electrical repulsion is lost and the viscosity is extremely reduced.

Namely, 1. For example, salts of polyacrylic acid such as sodium polyacrylate and salts of boe methacrylic acid such as sodium polymethacrylate can be excellent thickeners when dissolved in water, but they may be sensitive to certain electrolytes. Hold 1
For example, encountering an electrolyte such as sodium chloride in an aqueous system tends to reduce its viscosity rapidly.

The sodium ions (cations) in this electrolyte such as sodium chloride are opposed to the carboxyl anions (anions) of sodium polyacrylate, and the presence of this opposed ion electrically neutralizes the ions and causes repulsion. It is presumed that this loss causes the aforementioned viscosity reduction.

As a method to solve this problem, U.S. Patent No. 3,915,
No. 921, No. 4,509,949, etc., the carbon number is 1.
It is proposed to copolymerize esters of acrylic or methacrylic acid with 0 to 30 alkyl groups.

[Problem that the invention seeks to solve]

However, the higher fatty acid ester copolymers in the above-mentioned U.S. patents have the disadvantage that it takes a long time to dissolve the powder product in water, and when the copolymer content increases, a clear liquid cannot be obtained. Since it has properties such as turning into a milky white liquid without water, it has the disadvantage that its uses are naturally limited.

[Means for solving problems]

In view of the current situation, this invention has been developed by copolymerizing a water-soluble copolymer by combining two types of copolymer components, which are colorless and transparent, and have excellent salt resistance. Aqueous thickener.

It is an object of the present invention to provide an acrylic copolymer that can be used as a water absorbing agent, a water retaining agent, and the like.

That is, the water-soluble acrylic copolymer of the present invention can be obtained by copolymerizing a small amount of the compounds shown in (a) and (b) below with or without using a crosslinking agent. It is characterized by this.

(a) 90.0-98.5% by weight of acrylic acid or/and methacrylic acid.

(b) 10.0 to 1.5 IE amount% of the following general formula.

-0-X A compound represented by

However, Y.

(R is hydrogen or a methyl group).

X is.

(R2 in formula X is an alkyl group having 6 to 30 carbon atoms,
or alkylphenyl group.

1, m, n is 2m or n is ≧1. and 2<z+m+n<100. ) In the water-insoluble acrylic copolymer of the present invention, the monomer components are basically acrylic acid and/or methacrylic acid represented by compound (a), and the constituent proportions thereof are as follows: 90.0-98.5% (weight%; same below)
is within the range of

If the amount is less than 90.0%, the original performance as a thickener, water absorbing agent, or water retaining agent will decrease, and if it exceeds 98.5%, it will substantially exhibit salt resistance function.
(b) The amount of compound compounded is reduced.

As a result, the salt resistance of the resulting copolymer decreases, making it impossible to obtain a copolymer with desired performance.

The compound (a) has at least a portion of its carboxyl group 2, such as sodium hydroxide, potassium hydroxide,
It may be a neutralized monomer partially neutralized with a neutralizing agent such as an alkali metal hydroxide such as lithium hydroxide, or ammonia, or a volatile amine such as triethylamine or triethanolamine.

As one of the copolymerization components for acrylic acid and/or methacrylic acid, which is the compound (a).

-0-X In the compound (b) represented by oxyethylene unit! , m methyl group-substituted oxyethylene units, and n ethyl group-substituted oxyethylene positions, m and n are both 1 or more, and the sum of j, m, and n is 2.
The requirement is that it be greater than and less than 100.

R1 in X in compound (b) includes hexyl, heptyl, octyl, nonyl, decyl, lauryl, stearyl, octylphenyl, nonylphenyl, and the like.

In the formula of X, m or n≧1. and 2<J+m+n<100,
By satisfying this range, the water solubility and transparency of the resulting copolymer can be significantly improved.

(b) A typical compound among the compounds.

Allyl polyoxyethylene (β=10) polyoxypropylene (m=3) nonylphenol ether, allyl polyoxyethylene (A=7) polyoxypropylene (m=3) lauryl ether.

Allyl polyoxyethylene B = 14) polyoxypropylene (m = 3) stearyl ether, etc.

In addition, in this invention, the compound described below as a crosslinking agent may be copolymerized with the above-mentioned (a) compound and (b) compound to form a copolymer.

That is, a compound that is polymerizable with the compounds (a) and (b) and has two or more alkenyl ether groups per molecule of the parent polyhydric alcohol containing two or more carbon atoms and two or more hydroxyl groups. A polyalkenyl polyether of a polyhydric alcohol, specifically allylpentaerythritol.

Examples include trimethylolpropane diallyl ether and allyl saccharose.

The compound added as a crosslinking agent is desirably added in an amount of 5.0% or less based on the total monomer components.

Furthermore, in this invention, the compound (a), (
b) Other vinyl monomers having copolymerizability with these compounds may be blended and copolymerized with the compound and the above-mentioned crosslinking agent added as necessary.

The monomer as the fourth component is an alkyl acrylate or alkyl methacrylate in which the alkyl group has 1 to 4 carbon atoms, specifically ethyl acrylate or butyl acrylate.

Examples include methyl methacrylate.

It is preferable to use these in an amount of approximately 10% or less based on the total amount of monomers.

The water-soluble acrylic copolymer of the present invention can be easily obtained by copolymerizing the above-mentioned monomers by a conventional precipitation polymerization method or solution polymerization method, and the catalyst used is an azo-based copolymer. , peroxide type, redox type, and other radical polymerization initiators are suitable.

[For production]

The water-insoluble acrylic copolymer obtained by this invention is composed of (a) a compound of acrylic acid or/and methacrylic acid, and (b) a plurality of three different polyoxyethylene units represented by the compound. By copolymerizing long-chain vinyl monomers in a predetermined range, extremely high viscosity can be obtained at a certain concentration level, and even in thickened aqueous media, the salts therein can be copolymerized. It maintains stability without being influenced by

Therefore, when used as a viscoelastic modifier in latex coating compositions such as water-based coatings, it can impart excellent fluidity and homogeneity.

Also, when used to thicken printing paste for textiles etc.
Ease of formulation, compatibility with pigment dispersions.

It is possible to significantly improve the performance of printed materials in terms of gloss, etc.

Furthermore, in the present invention, a copolymer obtained by copolymerizing an arbitrary amount of 5% or less of the polyalkenyl ether of a polyhydric alcohol effective for crosslinking with the compounds (a) and (b) is used in an appropriate manner. It can be in the form of a three-dimensional network structure.

The thus obtained copolymer swells in an aqueous system to form a microgel, and exhibits superior effects in thickening, water absorption, water retention, etc.

〔Example〕

Hereinafter, this invention will be described in more detail with reference to Examples.

At the compounding ratio shown in Table 1 below, (a) acrylic acid as a compound, (b) allyl polyoxyethylene (A' = 10) and polyoxypropylene (m = 3) as a compound.
50 g of a monomer composition of nonylphenol ether was placed in a condenser-equipped flask (No. 11) with 450 g of benzene, and the atmosphere was replaced with nitrogen while stirring. Then, 3 g of penzole peroxide was added as a catalyst, and the temperature was kept at 70°C.
Allowed time to react.

After cooling, the precipitated copolymer powder was separated using a centrifuge and dried at a temperature of 55° C. to obtain a copolymer. (
Example 1) Similarly, as described in Table 1, (a) acrylic acid as a compound, (b) allyl polyoxyethylene (1=7) polyoxypropylene (m=
3) A copolymer was obtained by copolymerizing lauryl ether and tetraallyloxyethane as a crosslinking agent (C). (Example 2) Also, (a) methacrylic acid as a compound, (b)
Allyl polyoxyethylene (j!=14
) polyoxypropylene (ri=3) stearyl ether, allyl sucrose ether as crosslinker (c), and a fourth
A copolymer was obtained by blending ethyl acrylate as another copolymerizable monomer (d). (Example 3) 1.0 g of these copolymers was put into 200 ml of distilled water, 1 ml of 1ON NaOH was added to dissolve it, the appearance of the solution was observed, and then common salt was added to this solution. The viscosity was measured.

These results are shown in Table 1, and as a control, the performance of polyacrylic acid and crosslinked polyacrylic acid, which have been commonly used as thickeners, is also shown in Table 1.

Chapter 1 Table [Margin below] Note) The abbreviations for monomer compositions in Table 1 are as follows.

A A; acrylic acid MAA; methacrylic acid E Ai ethyl acrylate ENP: allyl polyoxyethylene (1=10) polyoxypropylene (m=3) nonylphenol ether E L, allyl polyoxyethylene (l=7) poly Oxypropylene (m=3) lauryl ether ES; allyl polyoxyethylene (l=14) polyoxypropylene (m=3) stearyl ether TAE; tetraallyloxyethane ASE, allyl shochu ether Note) 2 Table 1 The products marked with * are as follows.

*1: Julimar AC-10HP (polyacrylic acid manufactured by Nippon Tsumugi Pharmaceutical ■) *2: Shunron PW-110 (crosslinked polyacrylic acid manufactured by Nippon Tsumugi Pharmaceutical ■) Note) The results in the appearance column of Table 1 are 1 table salt. This is the appearance of the liquid before addition.

Note) 4 The viscosity measurements in Table 1 are measured values using a Brookfield B type viscometer (temperature 25°C, 12 PPM).

〔Effect of the invention〕

This invention mainly consists of at least the compound (a), acrylic acid and/or methacrylic acid, and the compound (b).
) A water-soluble acrylic copolymer with salt resistance and ion resistance can be easily and easily produced by copolymerizing compounds in a predetermined quantitative ratio.

Moreover, the salt-resistant water-soluble acrylic copolymer obtained thereby is economically obtainable.

It has many uses.

That is, it can be used as a printing paste having an excellent thickening effect, or as a latex for adhesives, paints, etc. by blending it into an aqueous system to be thickened, either in the form of an aqueous dispersion or in a dry form.

In addition, ceramics,
Modification of ceramics such as glazes, modification of cosmetics such as lotions and hair creams, modification of medicines such as ointments and poultices, and addition to detergents etc. to fully demonstrate their usefulness. It is.

On the other hand, the obtained salt-resistant water-soluble acrylic copolymer can be used as a water absorbing agent and water retaining agent in sanitary products such as disposable diapers and napkins, and as a water retaining agent for gardening, and as a retaining agent for pesticides and fertilizers for agricultural purposes.
It can be used in construction as a water-breathing wall material, and can also be used for firefighting to prevent the spread of fires, prevent water damage, and prevent the spread of forest fires.

Claims (4)

[Claims] (1) A water-soluble acrylic copolymer obtained by copolymerizing at least the compounds shown in (a) and (b) below with or without a crosslinking agent. (a) 90.0-98.5% by weight of acrylic acid or/and methacrylic acid. (b) 10.0 to 1.5% by weight of the following general formula, Y-O-
A compound represented by X. However, Y is ▲There is a mathematical formula, chemical formula, table, etc.▼ or CH_2=CH
-CH_2- (R is hydrogen or methyl group), and X is ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (R_1 in the formula , l, m, and n satisfy m or n≧1 and 2<l+m+n<100.) (2) The compound (a) is an alkali metal hydroxide,
The water-soluble acrylic copolymer according to claim 1, which is neutralized with one or more compounds selected from ammonia and amines. (3) The copolymer has two or more carbon atoms and two or more hydroxyl groups per molecule of the base polyhydric alcohol containing two or more carbon atoms and two or more hydroxyl groups as a crosslinking agent for the (a) compound and (b) compound. The water-soluble acrylic copolymer according to claim 1, which is a copolymer of a polyalkenyl polyether of a polyhydric alcohol having an alkenyl ether group in a proportion of 5% by weight or less. Combined. (4) The copolymer is composed of (a) compound, (b) compound, and a crosslinking agent that is added as necessary to these (a) compound and (b) compound. 4. The water-soluble acrylic copolymer according to any one of claims 1 to 3, which is obtained by copolymerizing monomers.