JP2778124B2 - Aqueous resin composition - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a novel aqueous resin composition, and more particularly, to an aqueous resin having a core-shell structure having extremely good alkali resistance, solvent resistance, and water resistance. It relates to a composition.

[Conventional technology]

Since the aqueous polymer dispersion (emulsion, latex) does not contain an organic solvent, there is no danger of fire and there is little problem that the working environment is deteriorated, so that it is applied to various fields.

However, synthetic rubber-based latex such as styrene-butadiene copolymer latex, acrylonitrile-butadiene copolymer latex, and ethylene- (meth) acrylic acid copolymer emulsion are added to pulp, asbestos, etc. by wet part, beater addition or the like. When the fibers and similar substances were coated or impregnated, satisfactory solvent resistance and alkali resistance were not developed.

Various attempts have been made to solve such disadvantages of the synthetic rubber latex and the acrylic resin emulsion.

For example, JP-A-63-99363 discloses an epoxy resin containing a carboxyl group in a graft chain, which is obtained by polymerizing a monomer mixture containing (meth) acrylic acid in the presence of an epoxy resin. Conjugation of a salt or a resin obtained by esterifying a carboxyl group-containing acrylic resin with an epoxy resin in the presence of an amine esterification catalyst or a salt thereof (hereinafter collectively referred to as a modified epoxy resin having a carboxyl group) in an aqueous medium. Diene compounds and / or
Alternatively, an aqueous resin composition containing a resin obtained by polymerizing a monoethylenically unsaturated monomer is disclosed.

An aqueous resin composition containing a resin obtained by polymerizing a conjugated diene and / or a monoethylenically unsaturated monomer in an aqueous medium of an ethylene- (meth) acrylic acid copolymer is disclosed in 57-137339 and JP-A-61-268349.

[Problems to be solved by the invention]

However, JP-A-63-99363 and JP-A-57-1
The aqueous resin compositions described in JP-A-37339 and JP-A-61-268349 were still insufficient in alkali resistance, water resistance and solvent resistance.

[Means for solving the problem]

The present inventors have conducted intensive studies in view of the above circumstances,
Modified epoxy resin having carboxyl group and ethylene-
The aqueous resin composition containing a resin obtained by polymerizing a conjugated diene compound and / or a monoethylenically unsaturated monomer in an aqueous medium containing both (meth) acrylic acid copolymers is the above-mentioned 3). The inventors have found that the present invention is excellent in any of the two types of durability, and have completed the present invention.

That is, the present invention provides a method for preparing a conjugated diene compound (C) in an aqueous medium containing [I] an olefin-ethylenically unsaturated carboxylic acid copolymer (A) and a modified epoxy resin (B) having an anionic group. ) And / or a resin (I) obtained by polymerizing a monoethylenically unsaturated monomer (D).

Further, the present invention provides [II] a method wherein the modified epoxy resin (B) having an anionic group is in excess of the monoethylenically unsaturated carboxylic acid graft copolymer (B ₁ ) of the epoxy resin or the epoxy resin and its epoxy group. The present invention provides the aqueous resin composition according to the above [I], which is a reaction product (B ₂ ) with an acrylic resin having a carboxyl group.

Further, [III] the amount of the modified epoxy resin (B) having an anionic group used is such that the conjugated diene compound (C) and / or
Or 4 to 4 times the total weight of the monoethylenically unsaturated monomer (D)
An object of the present invention is to provide the aqueous resin composition according to the above [I] in an amount of 20% by weight.

[IV] The weight ratio of the conjugated diene compound (C) to the monoethylenically unsaturated monomer (D) [the compound (C) and the monomer (D)] is 95/5 to 20/80. It is intended to provide the aqueous resin composition according to the above [I].

The resin (I) according to the present invention is obtained by using a radical polymerization initiator in an aqueous medium containing the copolymer (A) and the resin (B), usually using the compound (C) and / or The resin (I) is obtained by polymerizing the monomer (D), and the resin (I) usually has a core of a polymer of the compound (C) and / or the monomer (D). (A) and particles having a two-layer structure covered by a shell of the resin (B).

The olefin-ethylenically unsaturated carboxylic acid copolymer (A) according to the present invention is a copolymer of an olefinic hydrocarbon and an ethylenically unsaturated carboxylic acid or a salt thereof,
It may be a copolymer containing another copolymerizable monoethylenically unsaturated monomer component or a salt thereof.

The copolymer (A) may be produced by any method. For example, an autoclave is charged with an olefin gas in the presence of an organic solvent, and a radical polymerization initiator and a monoethylenically unsaturated carboxylic acid are added. An olefin-monoethylenically unsaturated carboxylic acid copolymer obtained by injecting an acid together with an organic solvent into an autoclave and reacting the mixture for 30 minutes to 6 hours, and then distilling off the solvent is exemplified.

Usually, this olefin-monoethylenically unsaturated carboxylic acid copolymer is used as an aqueous dispersion of a copolymer salt by adding distilled water and sodium hydroxide while stirring at 40 to 150 ° C.

Although the copolymerization ratio of the olefinic hydrocarbon and the ethylenically unsaturated carboxylic acid of the copolymer (A) is not particularly limited, monoethylene is contained in the total weight of the monomers constituting the copolymer (A). Those containing 1 to 10 mol% of the unsaturated carboxylic acid or its salt are preferred.

The olefinic hydrocarbons constituting the copolymer (A) include, for example, ethylene, propylene, butene, and pentene, and the ethylenically unsaturated carboxylic acids include (meth) acrylic acid, fumaric acid, itaconic acid, and maleic acid. Acid, azelaic acid, etc., as an atomic group forming a salt thereof, sodium, potassium, other ammonium salts, etc. of metals such as lithium, as other copolymerizable monoethylenically unsaturated monomer components, For example, methyl acrylate,
Methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate,
Butyl acrylate, butyl methacrylate, pentyl acrylate, pentyl methacrylate, hexyl acrylate,
Alkyl acrylates and alkyl methacrylates exemplified by hexyl methacrylate, heptyl acrylate, heptyl methacrylate, octyl acrylate, octyl methacrylate, octadecyl acrylate, octadecyl methacrylate, and the like; styrene, α-methylstyrene, vinyl Ethylenically unsaturated aromatic monomers exemplified by toluene, chlorostyrene, 2,4-dibromostyrene and the like; acrylonitrile, unsaturated nitriles such as methacrylonitrile; acrylic acid, methacrylic acid, crotonic acid, maleic acid and Its anhydrides, fumaric acid, itaconic acid, and monoalkyl esters of unsaturated dicarboxylic acids,
Monoethylenically unsaturated carboxylic acids such as monomethyl maleate, monoethyl fumarate and mono-n-butyl itaconate; vinyl esters such as vinyl acetate and vinyl propionate; vinylidene halides such as vinylidene chloride and vinylidene bromide; acrylics Hydroxyalkyl esters of ethylenically unsaturated carboxylic acids, such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate; ethylenically unsaturated, such as glycidyl acrylate and glycidyl methacrylate Glycidyl esters of carboxylic acids; and radical polymerization of acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N-butoxymethylacrylamide, diacetoneacrylamide, etc. Such monomers.

As the copolymer (A), a copolymer of an ethylene-monoethylenically unsaturated carboxylic acid containing 1 to 15 mol% of a monoethylenically unsaturated carboxylic acid or a salt thereof is preferable. Those having a water solubility or water dispersibility of 150,000 are preferred.

The modified epoxy resin (B) having an anionic group according to the present invention is a modified epoxy resin having an anionic group represented by a carboxyl group, a sulfonic acid group, a sulfate group, and a phosphate group, or a salt thereof. Among them, an alkali metal salt or an ammonium salt of a modified epoxy resin having a carboxyl group has a self-dispersing property and a conjugated diene compound (C) and / or a monoethylenically unsaturated monomer (D) described later. It is preferable because it can be emulsified.

Such preferred resin (B) is, for example, a monoethylenically unsaturated carboxylic acid of 10 mol% or more of all monoethylenically unsaturated monomers at 60 to 150 ° C. in a hydrophilic organic solvent in the presence of an epoxy resin. An acid and, if necessary, another copolymerizable monoethylenically unsaturated monomer, a radical polymerization initiator such as benzoyl peroxide is used in an amount corresponding to 3 to 12% by weight of the total monomers. Tertiary amine salt or alkali metal salt of a monoethylenically unsaturated carboxylic acid graft copolymer of an epoxy resin produced by graft polymerization of an epoxy resin, and a monoethylenically unsaturated carboxylic acid containing at least 20% by weight of a monoethylenically unsaturated carboxylic acid. An acrylic resin having a carboxyl group and a number average molecular weight of 5,000 to 20,000 obtained by polymerizing an ethylenically unsaturated monomer in an organic solvent at 50 to 150 ° C., and a bisphenol having a number average molecular weight of 1500 to 6000 A tertiary amine salt of a reaction product obtained by reacting a phenol A type epoxy resin with an oxirane group / carboxyl group equivalent ratio of 1/2 to 1/20 at 50 to 150 ° C. Can be As such a commercially available product, there is Dick Fine GN-0280 (manufactured by Dainippon Ink and Chemicals, Inc.).

As the conjugated diene compound (C) according to the present invention, for example, butadiene-1,3,2-methyl-butadiene-1,3,2
Chlorobutadiene-1,3 and the like, but in consideration of copolymerizability with other monomers and economy, butadiene
It is preferred to use 1,3.

As the monoethylenically unsaturated monomer (D) according to the present invention, any other copolymerizable monoethylenically unsaturated monomer in the olefin-ethylenically unsaturated carboxylic acid copolymer (A) can be used. Can be used.

The compound (C) and / or the monomer (D) reacted with the copolymer (A) in the presence of the resin (B) may be any one of the compound (C) and the monomer (D). Although only one of them may be used, the compound (C) and the monomer (D) are usually used in combination. When the polymerization ratio of the compound (C) to the monomer (D) [(C) / (D)] is from 95/5 to 20/80, it is particularly preferable because the properties of the latex are exhibited.

Furthermore, the ratio of the weight of the resin (B) to the total weight of the compound (C) and the monomer (D) [(B) / (C) +
(D)] is excellent in polymerization stability during production of the resin (I), and a resin (I) having a high polymerization rate and excellent durability can be obtained, so that [(B) / (C) + (D)] = 4/96 to 20/80
It is preferred that

Further, the ratio of the total weight of the copolymer (A) and the resin (B) to the total weight of the compound (C) and the monomer (D) during the production of the resin (I) [(A) + (B) /
(C) + (D)] is not particularly limited, but [(A) +
(B) / (C) + (D)] = 70/30 to 30/70 is preferable for forming the core-shell structure of the resin (I).

The method for producing the resin (I) according to the present invention comprises the step of: reacting the compound (C) and / or the monomer (D) in an aqueous medium containing the copolymer (A) and the resin (B). Other reaction conditions and the like are not particularly limited as long as they are polymerized. For example, the compound (C) and / or the compound (C) are mixed in an aqueous medium in which the copolymer (A) and the resin (B) are mixed. Alternatively, the monomer (D) is dispersed in water, and a radical polymerization initiator such as an aqueous initiator such as potassium persulfate, sodium persulfate, ammonium persulfate, or hydrogen peroxide, benzoyl peroxide, methyl ethyl ketone peroxide, t -Butyl hydroperoxide, from an oily initiator such as cumene hydroperoxide, room temperature to 150 ° C., preferably 40
What is necessary is just to perform radical polymerization at -90 degreeC.

The resin (I) according to the present invention contains, as a main component, a resin having a structure in which the copolymer (A) and the resin (B) are graft-polymerized with the compound (C) and / or the monomer (D). Although it may be contained, the resin (I) containing, as a main component, a resin having no graft-polymerized structure in that alkali resistance, water resistance and solvent resistance are superior to resins having a graft-polymerized structure. Preferably, there is.

The amount of the radical polymerization initiator used at the time of the radical polymerization is usually the amount of the compound (C) and / or the monomer (D).
In order to make the resin (I) a resin not having a structure in which the main component is graft-polymerized, the initiator used and the amount of the initiator may be adjusted as required. It is preferable to select an appropriate one.

Further, at the time of producing the resin (I), an emulsifier is not used, and the radical polymerization is obtained by utilizing the stabilizing effect of the copolymer (A) and the resin (B) in an aqueous phase. I)
However, a known and commonly used emulsifier that is usually used when performing radical emulsion polymerization may be used as necessary.
The aqueous resin composition containing the resin (I) thus obtained has a pH of about 8 to 10, and a viscosity of about 30 to 1000 cps.

In the present invention, additives usually used in emulsion polymerization, such as a chain transfer agent, a polymerization stabilizer, and ethylenediaminetetraacetic acid for the purpose of buffering effect, may be used as required.

The aqueous resin composition containing the resin (I) of the present invention can be concentrated to a required solid content by, for example, a method such as stripping.

In the aqueous resin composition of the present invention, if necessary or necessary, a crosslinking agent such as a polyisocyanate compound, a urea resin, a melamine resin and an epoxy resin, a crosslinking catalyst such as ammonium chloride and ammonium paratoluenesulfonate, a surfactant Known additives such as colorants, preservatives, flame retardants, water / oil repellents, softeners, and fluorescent dyes can also be used in combination.

Since the aqueous resin composition of the present invention is further excellent in strength and stability of impregnation or spray application to various substrates, binders for various substrates such as paper, synthetic fibers, natural fibers, glass fibers and carbon fibers. Useful as a resin for applications.

For example, a binder for non-woven fabric processing can be blended based on the aqueous resin composition of the present invention, and the non-woven fabric processed with this binder is resistant to washing due to the alkalinity, water resistance and solvent resistance of the resin (I). Good dry cleaning resistance.

Next, the present invention will be described specifically with reference to examples. In addition,
The number of copies indicated in the text indicates parts by weight. Hereinafter, the “aqueous resin composition” is referred to as “latex”.

Example 1 Production of an Aqueous Dispersion of Ethylene-Methacrylic Acid Copolymer In a 5-volume autoclave purged with nitrogen, 1500 parts of t-butanol was charged, and ethylene was filled to 100 atm. Under stirring, 3 parts of azobisisobutyronitrile and 20 parts of methacrylic acid were fed into an autoclave together with 900 parts of t-butanol.

After stirring for about 4 hours, after the reaction, t-butyl alcohol was distilled off to obtain a copolymer (a). This copolymer (a) is mixed with 120
Water and sodium hydroxide with vigorous stirring at
An aqueous dispersion of a sodium salt of the ethylene-methacrylic acid copolymer (a) was produced. This aqueous dispersion has a solid content of 20%,
The viscosity was 1080 cps and the pH was 9.0.

Synthesis of modified epoxy resin having carboxyl group (1) n-butanol 120 parts (2) Epicoat 1010 150 parts (3) methacrylic acid 25 parts (4) styrene 10 parts (5) ethyl acrylate 2 parts (6) peroxide Benzoyl 3 parts (7) n-butanol 10 parts (1) and (2) were charged into a four-necked flask purged with nitrogen gas, and heated and dissolved. A solution obtained by uniformly mixing (3) to (7) was gradually dropped into this solution over 2 hours while stirring at 100 ° C. in the flask. After dropping,
The mixture was further stirred at the same temperature for 4 hours to obtain a solution of the modified epoxy resin (b) having a carboxyl group having a solid content of 58% in n-butanol.

Preparation of aqueous dispersion of modified epoxy resin having carboxyl group (8) 100 parts of n-butanol solution of modified epoxy resin (b) having carboxyl group (9) 4 parts of dimethylethanolamine (10) 260 parts of ion-exchanged water Nitrogen (8) was charged into a four-necked flask filled with gas, heated to 100 ° C., and a mixed solution of (9) and (10) was added dropwise over 30 minutes while stirring to obtain a modified epoxy resin having a carboxyl group. An aqueous dispersion of dimethylethanolamine salt (b) was obtained. Further, under reduced pressure, 130 parts of n-butanol and water were distilled off by azeotropic distillation, and the nonvolatile content was 25%.
The aqueous dispersion of dimethylethanolamine salt of the modified epoxy resin (b) having a carboxyl group not containing n-butanol was obtained.

Synthesis of latex In a nitrogen-substituted autoclave equipped with a stirrer, 5 parts of an aqueous dispersion of a dimethylethanolamine salt of a modified epoxy resin (b) having a carboxyl group as a solid content,
50 parts of an aqueous dispersion of the sodium salt of the methacrylic acid copolymer (a) as solids, 100 parts of ion-exchanged water, 50 parts of butadiene, 10 parts of methyl methacrylate, acrylonitrile
Forty parts and 0.5 part of potassium persulfate were charged and polymerization was carried out at 60 ° C. with stirring until the conversion reached 95% or more.

 The polymerization reaction proceeded smoothly without generation of aggregates.

Subsequently, unreacted monomers were removed and concentrated by steam distillation to obtain latex A having a pH of 8.1, a solid content of 50.0%, and a viscosity of 142 cps.

The particles of latex A were fixed in osmic acid and ruthenic acid while being dispersed in water, treated with polyvinyl alcohol, and stained with osmic acid to prepare a sample of ultrathin section.

Observation of this sample with a transmission electron microscope (magnification 100,000 times) revealed that the latex A particles consisted of a copolymer of butadiene, methyl methacrylate and acrylonitrile as the core, and a modified epoxy resin having a carboxyl group on the outside and ethylene-ethylene. It was found that the particles had a two-layer structure covered with the unsaturated unsaturated carboxylic acid copolymer.

Next, latex A is cast on a glass plate so that the dry film thickness becomes 0.1 to 0.2 mm, and the film obtained by natural drying at 20 ° C. for 48 hours is heated at 140 ° C. for 5 minutes. To make a test piece, and to pull it with Tensilon at a pulling speed of 500mm / mi
The strong elongation of the film was measured under the conditions of n. The film was rich in elasticity and toughness, and had a tensile strength of 250 kg / cm ² and an elongation of 700%.

Next, test specimens of 5 cm × 5 cm, 10 cm × 3 cm and 5 cm × 5 cm were prepared from the film, and each was immersed in a 0.05 N sodium hydroxide aqueous solution, distilled water, and perchren at 60 ° C. for 10 days, and 0.5 N hydroxylated respectively. The area swelling rate (%) (sodium resistance) by immersion in a sodium aqueous solution, the dimensional change rate (%) (water resistance) by immersion in water, and the area swelling rate (%) (solvent resistance) by immersion in perclene were measured. The results are shown in Table 1. As is clear from Table 1, latex A has extremely excellent alkali resistance, water resistance and solvent resistance.

Comparative Example 1 Dodecylbenzenesulfonic acid was used without using an aqueous dispersion of a dimethylethanolamine salt of a modified epoxy resin (b) having a carboxyl group and a sodium dispersion of a sodium salt of an ethylene-methacrylic acid copolymer (a). Emulsion polymerization was carried out in the same manner as in Example 1 except that one part of soda was used, and then unreacted monomers were removed and concentrated to obtain a pH of 8.
0, a latex a having a solid content of 50.0% and a viscosity of 500 cps was obtained.

Next, a film was prepared in the same manner as in Example 1, and the strength, alkali resistance, water resistance, and solvent resistance of the film were measured. The results are shown in Table 1.

Comparative Example 2 Aqueous dispersion of ethylene-methacrylic acid copolymer (a)
50 parts (solid content) and sodium dodecylbenzenesulfonate 5
The emulsion polymerization was carried out in the same manner as in Example 1 except that parts were used, and then unreacted monomers were removed and concentrated to obtain a latex a ′ having a pH of 9.5, a solid content of 50.0%, and a viscosity of 250 cps.
I got

Next, a film was prepared in the same manner as in Example 1, and the strength, alkali resistance, water resistance and solvent resistance of the film were measured. The results are shown in Table 1.

Comparative Example 3 Polymerization was carried out in the same manner as in Example 1 except that the aqueous dispersion of the ethylene-methacrylic acid copolymer (a) was not used, and then unreacted monomers were removed and concentrated to adjust the pH to 8.
0, a latex a ″ having a solid content of 50.0% and a viscosity of 200 cps was obtained.

Next, a film was prepared in the same manner as in Example 1, and the strength, alkali resistance, water resistance and solvent resistance of the film were measured.
The results are shown in Table 1.

Comparative Example 4 Aqueous dispersion of dimethylethanolamine salt of latex a modified epoxy resin (b) having carboxyl group obtained in Comparative Example 1 and ethylene-methacrylic acid copolymer (a) obtained in Comparative Example 1
The aqueous dispersion of sodium salt of
Latex A 'was obtained by mixing at a ratio of 100: 4: 50.

Next, a film was prepared in the same manner as in Example 1, and the elongation, water resistance and solvent resistance of the film were measured. The result is
It is shown in the table.

Example 2 A stainless steel reaction vessel equipped with a stirrer, condenser, thermometer and dropping funnel purged with nitrogen was charged with a starting material having the following composition.

Deionized water 140 parts Aqueous dispersion of dimethylethanolamine salt of modified epoxy resin (b) having a carboxyl group 10 parts (solid content) Aqueous dispersion of sodium salt of ethylene-methacrylic acid copolymer (a) 50 parts (Solid content) Then, while maintaining the liquid temperature in the container at 60 ± 2 ° C., 86 parts of n-butyl acrylate and acrylonitrile 10
Part, N-methylol acrylamide 2 parts, methacrylic acid 2 parts and a monomer mixture and a catalyst solution obtained by dissolving 0.3 parts of ammonium persulfate in 10 parts of deionized water are dropped and polymerized over 180 minutes. The stirring was continued at the same temperature for 60 minutes.

After stirring, cool the contents to 30 ° C.
%, PH 8.3 and viscosity 470 cps.

Next, a film was prepared in the same manner as in Example 1, and the elongation, water resistance and solvent resistance of the film were measured. The result is
It is shown in the table.

Application Example Latex A, a, a ', a ″ and latex B are each diluted with water to adjust the solid content to 10%, then impregnated into a 40 g / m ² basis weight polyethylene web and dried at 80 ° C for 5 minutes. After, 80 ℃
For 1 minute to obtain a nonwoven fabric of resin solid content / fiber = 25/100 (weight ratio). Next, according to the nonwoven fabric fabric test method (JIS L-1085), the morphological change of the nonwoven fabric in the dry cleaning strength and the washing strength test of the nonwoven fabric was evaluated. The results are shown in Table 2.

 The evaluation criteria are as follows.

[Effect of the Invention] The film obtained from the aqueous resin composition of the present invention is excellent in both alkali resistance, water resistance and solvent resistance as compared with that of the conventional aqueous resin composition, and Polyethylene which could not be expected to have high adhesiveness with resin,
It has surprising adhesion to non-polar substrates such as polypropylene.

Therefore, the aqueous resin composition of the present invention can be used in various fields such as a binder for a foam, a binder for a glass fiber, a primer coating agent, a coating agent, and a water-based paint, as well as a binder for a nonwoven fabric.

Claims (4)

(57) [Claims] A conjugated diene compound (C) and / or an olefin-ethylenically unsaturated carboxylic acid copolymer (A) and a modified epoxy resin (B) having an anionic group in an aqueous medium containing the modified epoxy resin (B). Or an aqueous resin composition comprising a resin (I) obtained by polymerizing a monoethylenically unsaturated monomer (D). 2. The modified epoxy resin (B) having an anionic group is characterized in that the epoxy resin is a monoethylenically unsaturated carboxylic acid graft copolymer (B ₁ ) or an epoxy resin and a carboxyl group in excess of the epoxy group. The composition according to claim 1, which is a reaction product (B ₂ ) with an acrylic resin. 3. The amount of the modified epoxy resin (B) having an anionic group used is from 4 to 20% by weight of the total weight of the conjugated diene compound (C) and / or the monoethylenically unsaturated monomer (D). The composition according to claim 1, wherein the amount is 4. The weight ratio of the conjugated diene compound (C) to the monoethylenically unsaturated monomer (D) [compound (C) / monomer (D)] is from 95/5 to 20/80. The composition according to claim 1, which is: