JPH0151490B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides paints and adhesives that have excellent adhesion and adhesion to the surface of a substrate wet with water or under a wet condition, especially in water. The present invention relates to a curable composition useful for lining, putty, sealing, etc. that can be easily applied over large areas.

[Conventional technology]

Currently, resins used for lining, putty, sealing, etc. include epoxy resin, vinyl ester resin, and polyurethane resin.
Each of these resins has its own characteristics and is widely used.

However, these existing resins do not have good adhesion to the base material when painted on a wet base material (for example, concrete), or when being immersed in seawater immediately after painting on the coast. The reality is that performance such as adhesiveness is not satisfactory and improvements are required.

Epoxy resins that use polyamide resin as a curing agent, which is obtained by condensation of xylylene diamine and dimer acid, are also known as underwater curable resins, but this resin actually has no adhesive properties on water surfaces. has the disadvantage of severe dispersion and poor reliability. Furthermore, in order to cure in water, the curing must be accelerated, and because of its rapid curing properties, the pot life is short at 20 to 30 minutes, making it unsuitable for large-area construction.

Generally, when applying protective lining to steel structures at work sites, it is often difficult to completely remove rust before painting. Therefore, in many cases, it is necessary to paint only to remove loose rust, and there are cases where sufficient adhesion and rust prevention properties are required even under such adverse conditions.

A method of mixing synthetic resin emulsion and cement has been known for a long time, but this method takes a long time to cure, and the film may come into contact with water in an uncured state after painting, or it may be exposed to high humidity. If placed in an environment of However, they have drawbacks such as slow curing, insufficient adhesion, and depending on the thickness of the film, hair cracks may occur and the film no longer functions as a film.

[Problem that the invention seeks to solve]

In view of the above-mentioned circumstances, the present inventors have developed paints and adhesives that have excellent adhesion and adhesion to the surface of a substrate wet with water or under a wet condition, particularly for lining, putty, sealing, etc. As a result of various studies on curable compositions useful for
The present inventors have also discovered that it has excellent adhesion and adhesion to the surface of a substrate wet with water or under a wet condition, and is also excellent in large-area construction under water, leading to the completion of the present invention.

[Means for solving problems]

That is, the curable composition of the present invention comprises (A) a side chain hydroxyl group of an acrylic rubber having a hydroxyl group in the side chain obtained by copolymerizing an acrylic ester, acrylonitrile, and a hydroxyl group-containing monomer; A urethane bond in the side chain obtained by reacting an isocyanate group of an unsaturated isocyanate having at least one isocyanate group and an acryloyl group or a methacryloyl group (hereinafter both are referred to as (meth)acryloyl group). It is characterized by comprising a side chain double bonding agent acrylic rubber having a (meth)acryloyl group via (B) a polymerizable monomer and (C) cement.

[Effect]

The side chain double bond type acrylic rubber used in the present invention has a side chain hydroxyl group of acrylic rubber, which has a hydroxyl group in the side chain obtained by copolymerizing an acrylic acid ester, acrylonitrile, and a hydroxyl group-containing monomer, and a side chain hydroxyl group in the molecule. Each is obtained by reacting at least one isocyanate group with the isocyanate group of an unsaturated isocyanate having a (meth)acryloyl group.

Acrylic acid esters used as monomer components of acrylic rubber having a hydroxyl group in the side chain include esters of acrylic acid such as methyl, ethyl, butyl, and 2-ethylhexyl. Among these, acrylic acid ethyl ester ,
Acrylic acid butyl ester is preferred. Also,
Examples of the hydroxyl group-containing monomer include hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and methylolacrylamide, among which hydroxyethyl acrylate and hydroxypropyl methacrylate are preferred examples.

Copolymerization of acrylic ester, acrylonitrile and hydroxyl group-containing monomers
Weight ratio of 90:5 to 25:1 to 15, preferably 75 to
It is carried out at a weight ratio of 85:10 to 20:5 to 10.

The copolymerization reaction can be carried out according to the method for producing acrylic rubber. For example, an acrylic rubber having a hydroxyl group in the side chain can be obtained by emulsion polymerizing a three-component monomer mixture within the above composition range using an anionic activator or by copolymerizing it in an organic solvent.

The unsaturated isocyanate used in the present invention is
They each have at least one isocyanate group and one (meth)acryloyl group in the molecule, and can be broadly classified into the following two types.

(b) Isocyanatoethyl methacrylate (hereinafter referred to as
(referred to as IEM).

(b) Addition product of diisocyanate and unsaturated monoalcohol containing (meth)acryloyl group Diisocyanate includes 2,4-tolylene diisocyanate, unsaturated monoalcohol containing (meth)acryloyl group (hereinafter simply An unsaturated isocyanate prepared using 2-hydroxyethyl methacrylate as an unsaturated monoalcohol (referred to as an unsaturated monoalcohol) is shown.

In principle, 1 mole of unsaturated monoalcohol is used for 1 mole of diisocyanate in the production of unsaturated isocyanate, but 2,4
- Even when there is a significant difference in reactivity between two isocyanate groups, such as tolylene diisocyanate, the unsaturated isocyanate depicted in the model cannot be obtained alone; types of diisocyanates, unsaturated isocyanates,
A mixture of oligoacrylates is formed.

Undesirable among these components are free diisocyanates, which can result in residual gelation or abnormally increased viscosity, making handling difficult.

When reacting with acrylic rubber having side chain hydroxyl groups, the residual amount of diisocyanate must be 0.1 (wt%) or less.

In order to remove free diisocyanate, it is necessary to increase the amount of the unsaturated monoalcohol component to more than the specified moles, or to remove the diisocyanate by distillation under reduced pressure after the reaction is completed.

In addition, since unsaturated monoalcohols have (meth)acryloyl groups, reduced pressure at high temperatures polymerizes the (meth)acryloyl groups and gels as bonds. Measures such as depressurization are necessary.

Oligoacrylates, which are another so-called by-product, do not impede the invention.

If its abundance is fixed, it will be useful for improving physical properties, for example, increasing heat distortion temperature.

Therefore, a practically easy method for producing unsaturated isocyanate is to use 1 mol or more of unsaturated monoalcohol per 1 mol of diisocyanate, and the most appropriate molar ratio is 1.2 mol or more and 1.5 mol or less. be.

For example, when 1.2 mol of unsaturated monoalcohol is used per 1 mol of diisocyanate, the following mixture is obtained.

(a) Unsaturated isocyanate (b) Oligoacrylate This can be used as it is for reaction with acrylic rubber having a hydroxyl group in the side chain.

Examples of diisocyanates for forming unsaturated isocyanates include the following types.

2,4-tolylene diisocyanate, 2,4-
Mixture of tolylene diisocyanate and 2,6-tolylene diisocyanate, paraphenylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate , hexamethylene diisocyanate, isophorone diisocyanate.

The preferred type is 2,4-tolylene diisocyanate, such as isophorone diisocyanate.
There are differences in the reactivity of individual isocyanate groups.

Furthermore, as the unsaturated monoalcohol used for the reaction with diisocyanate, the type having a (meth)acryloyl group and a hydroxyl group in one molecule obtained by reacting acrylic acid or methacrylic acid with an alkylene monoepoxide can be used. Things can be given. Hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylate are preferably used.

The reaction ratio of the acrylic rubber having a hydroxyl group in the side chain and the unsaturated isocyanate is 0.01 equivalent or more of isocyanate group (i.e. unsaturated isocyanate) per equivalent of hydroxyl group, but
The amount is preferably 0.1 equivalent or more and 1 equivalent or less.

If the amount of isocyanate groups is 0.01 equivalent or less, the physical properties of the curable composition, such as adhesiveness and hardness, will not be sufficiently exhibited.

In addition, when using more than 1 equivalent of isocyanate groups, the reacting hydroxyl groups disappear, and the isocyanate groups further react with the generated urethane bonds to form allophanate bonds, resulting in increased viscosity and strong thixotropy. It comes to show.

The most desirable range is from 0.1 equivalent to 1 equivalent of isocyanate group per equivalent of hydroxyl group.

During the reaction, it is necessary to use a polymerization inhibitor to prevent gelation, and it is advantageous to use a reaction accelerator such as a tertiary amine or an organic tin compound to shorten the reaction time.

The polymerizable monomer used in the present invention is one that dissolves the side chain double bond type acrylic rubber, and is selected from the viewpoint of improving the water resistance and adhesion of the coating film after curing. However, since the above-mentioned rubber is solid, it is inconvenient to mold and harden it as it is, so it is used for the purpose of dissolving it and making it easier to handle.

Examples of the polymerizable monomer used in the present invention include the following types.

(a) Methacrylic acid esters, such as methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, tertiary butyl methacrylate,
Butyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, benzyl methacrylate,
Trimethylolpropane methacrylate.

(b) Acrylic esters, such as methyl acrylate, ethyl acrylate, butyl acrylate,
Butanediol diacrylate, hexanediol diacrylate.

(c) Vinyl acetate, vinyl propionate.

(d) Although it does not have the power to dissolve side chain double bond type acrylic rubber alone, it can be dissolved in another solvent such as methyl ethyl ketone, then a polymerizable monomer is added as a diluent, and the unsaturated isocyanate is reacted. There is also a method of increasing the solubility in a solvent and monomer, and then distilling off methyl ethyl ketone as necessary to obtain a monomer solution.

Suitable monomers for this purpose include, for example, styrene, vinyl ketone, divinylbenzene, methacrylonitrile, and the like.

Of course, any of the above monomers can be used in combination. The polymerizable monomer of the present invention is used by being blended with the rubber, and is preferably blended by being used as a solvent during the production of the rubber.
The most preferred monomer is methyl methacrylate.

The amount of polymerizable monomer used must be at least the amount that dissolves the rubber, and although the amount varies depending on the type of individual monomer, it is usually in the range of 0.3 to 3 times the amount of the rubber. It is preferably used in

The cement used in the present invention is necessary for accelerating hardening in water or under wet conditions, particularly in water, and for developing hardness of the cured product. As the cement, a commonly available commercially available type called Portland cement or alumina cement is sufficient, although white cement can also be used.

The amount of cement used is 50 to 250 parts by weight, preferably 100 to 160 parts by weight, based on 100 parts by weight of the total amount of the rubber and polymerizable monomer.

Peroxides are used to cure the curable compositions of the present invention. In the absence of peroxide, it takes a long time to develop final hardness, which considerably impairs practicality.

Peroxides include ketone peroxides such as methyl ethyl ketone peroxide, cyclohexanone peroxide, acetylacetone peroxide, and ethyl acetoacetate peroxide, acyl peroxides such as lauroyl peroxide and benzoyl peroxide, cumene hydroperoxide, and t. - Examples include organic peroxides such as hydroperoxides such as butyl hydroperoxide, and peroxy esters such as tert-butylperoxybenzocoat.

The amount of peroxide blended is 0.5 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the total amount of the rubber and polymerizable monomer. If the amount of peroxide added is less than 0.5 parts by weight, the curing properties at room temperature will be insufficient. On the other hand, if the amount of peroxide added is more than 10 parts by weight, the effect of increasing the amount will not be observed. However, it has disadvantages of high cost and deterioration of the physical properties of the cured product.

In order to accelerate the curing of peroxide, it is preferable to use peroxide and a curing accelerator together. Examples of hardening accelerators include cobalt organic acid salts,
Examples include panadium acetylacetonate and dimethylaniline.

The amount of the curing accelerator is 0.01 to 10 parts by weight based on 100 parts by weight of the total amount of the rubber and polymerizable monomer.
Preferably, it is within the range of 0.1 to 5 parts by weight.

The curable composition of the present invention is prepared by uniformly mixing a side chain double bond type acrylic rubber, a polymerizable monomer, cement, and, if necessary, a peroxide and a curing accelerator. However, if necessary, other fillers, reinforcing materials, colorants, radical curing resins such as unsaturated polyester resins and vinyl ester resins, and other additives may be added.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Synthesis of side chain double bond type acrylic rubber (A) Anionic monomer mixture with the composition of butyl acrylate 75 mol (%), acrylonitrile 20 mol (%), and 2-hydroxyethyl acrylate 5 mol (%) 200 parts of acrylic rubber having a hydroxyl group in the side chain obtained by emulsion polymerization using an activator, salting out, washing with water, and drying was dissolved in 300 parts of methyl methacrylate to form a viscous solution, and 1 part of hydroxyethyl methacrylate was added. 35 g of unsaturated isocyanate, which is an adduct of 1.2 moles of isophorone diisocyanate, 0.02 g of hydroquinone, and 0.3 parts of dibutyltin dilaurate were added, and the mixture was heated and stirred at approximately 70°C for 5 hours in a stream of air, resulting in infrared analysis. As a result, most of the free isocyanate groups disappeared, and a methyl methacrylate solution of the side chain double bond type acrylic rubber (A) was obtained.

performance test An adhesive was manufactured with the following formulation.

Side chain double bond type acrylic rubber (A) 50 parts Alumina cement 60 parts Paramenthane hydroperoxide 2 parts Dimethylaniline 0.2 parts Cobalt naphthenate (6% Co) 1 part It takes about 2 days to complete curing in water. It took.
Putty was applied to a steel plate in water to a thickness of about 2 mm, and after it had hardened for a week, an adhesion test using an elcometer showed an adhesive strength of 40 to 60 kg, confirming that the adhesive was extremely good. Ta.

Example 2 Production of side chain double bond agent acrylic rubber (B) Into a separable flask equipped with a stirrer, a turbid flow condenser, a thermometer, and a gas inlet tube, 80 mol (%) of ethyl acrylate and 15 mol (%) of acrylonitrile were added. %), 300 g of mixed monomers of 5 moles (%) of 2-hydroxyethyl methacrylate, and 200 g of acetone.
g, prepare 3 g of azobisisobutyronitrile,
Polymerization was carried out at the boiling point of acetone in a nitrogen stream for 10 hours.

The polymerization rate reached 98 (%).

Add 0.1g of hydroquinone to stop polymerization, lower the temperature to 60℃, and switch to dry air. Isocyanate ethyl methacrylate 20 from Dow Chemical Company, USA.
After adding 1 g of dibutyltin dilaurate and reacting at the same temperature for 3 hours, it was determined that the isocyanate groups had completely disappeared as a result of infrared analysis.

Add 200g of methyl methacrylate and under reduced pressure (≒
Acetone was removed at 200 mmHg), and a total of 500 g of methyl methacrylate was added in two portions. The end point was determined from the measurement of the refractive index and was stopped when it coincided with that of methyl methacrylate.

After monomer replacement, the solid content was determined by measuring the total weight.
A side chain double bond type acrylic rubber (B) (methyl methacrylate solution) containing 290 g of methyl methacrylate and 580 g of methyl methacrylate was obtained with a viscosity of about 130 poise.

The following formulation was kneaded to produce a putty-like material.

Side chain double bond type acrylic rubber (B) 100 parts (methyl methacrylate solution) Portland cement 150 parts Cumene hydroperoxide 3 parts Cobalt naphthenate 1 part The putty was stable at room temperature for about 12 hours, but in water about 2 Lost liquidity after hours.

The adhesive strength by tensile shear when steel plate to steel plate is cured in water is 103 to 141 Kg/cm ² , about 2 mm thick.
A tensile adhesion test using an Elcometer when the coating film on a steel plate was cured in water showed 50 to 70 kg,
It showed very good adhesion.

〔Effect of the invention〕

The curable composition of the present invention cures in water, has excellent adhesion and adhesion to the surface of a desired substrate even in water or under wet conditions, and has excellent water resistance and chemical resistance. Because of the paint,
Useful as an adhesive. In particular, it is suitable for lining and casting over a wide area underwater, and is therefore useful for repairing drain pits, etc. as protective linings under water for marine structures.

Claims (1)

[Scope of Claims] 1 (A) A side chain hydroxyl group of an acrylic rubber having a hydroxyl group in the side chain obtained by copolymerizing an acrylic acid ester, acrylonitrile, and a hydroxyl group-containing monomer, and at least one hydroxyl group in each molecule. Side chain double bond type having an acryloyl group or methacryloyl group in the side chain via a urethane bond, obtained by reacting an isocyanate group with an isocyanate group of an unsaturated isocyanate having an acryloyl group or methacryloyl group. A curable composition consisting of acrylic rubber, (B) a polymerizable monomer, and (C) cement.