JPS61275322A - Curable composition - Google Patents

Abstract

PURPOSE:The titled composition having a long pot life, excellent workability, excellent film hardness, etc., and being suitable for a paint, etc., obtained by mixing an aqueous emulsion with an oligomer having an isocyanate group and a (meth)acryloyl group and a peroxide. CONSTITUTION:The purpose curable composition is obtained by mixing an aqueous emulsion (A) (e.g., ethylene/vinyl acetate copolymer resin emulsion) with an isocyanate oligomer (B) containing 1 equivalent or below of isocyanate groups and 1 equivalent or above of (meth)acryloyl groups in the molecule [e.g., a compound of the formula (wherein n is 1-5)] and a peroxide (C) (e.g., t-butyl hydroperoxide). Component B can be synthesized by, for example, an addition reaction between a (meth)acryloyl group-containing unsaturated monoalcohol (e.g., 2-hydroxyethyl acrylate) and an oligomer having an isocyanate group on each end.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a water-based emulsion film that can be cured at room temperature, has a long pot life, is excellent in workability, and is improved. The present invention relates to a curable composition having a high adhesive strength.

[Conventional technology]

Currently, known methods for forming a film from an aqueous emulsion and curing it include a method of adding a polyvalent isocyanate compound to an aqueous emulsion, a method of adding a polyvalent aziridine compound to an aqueous emulsion, and the like. but,
The method of adding a polyvalent isocyanate compound to an aqueous emulsion has the disadvantage that the pot life of the aqueous emulsion is short, while the method of adding a polyvalent aziridine compound to an aqueous emulsion has the disadvantage of relatively high cost. have

It is extremely useful for expanding the uses of aqueous emulsions to cure adhesives and the like made of aqueous emulsions at room temperature and to improve their physical properties without significantly increasing costs.

[Problem that the invention seeks to solve]

As a result of intensive studies in view of the above-mentioned circumstances, the present inventors found that (1) an aqueous emulsion contains (2) an oligomer having a specific ratio of (meth)acryloyl groups and isocyanate groups in the molecule; ) A composition containing monomers copolymerizable with the oligomer and (4) peroxide as needed can cure an aqueous emulsion film at room temperature, is inexpensive, and has a long pot life. The present inventors have discovered that the adhesive is long, has excellent workability, and has improved adhesive strength, leading to the completion of the present invention.

[Means for solving problems]

That is, the present invention provides D(1) an aqueous emulsion, (2) an unsaturated isocyanate oligomer containing one equivalent or less of isocyanate group and one equivalent or more of acryloyl group or methacryloyl group in one molecule, and (3) peroxide, and 2) (1) an aqueous emulsion; (2) an unsaturated isocyanate oligomer containing one equivalent or less of isocyanate group and one equivalent or more of acryloyl group or meta(lyloyl group); (3) ) A curable composition comprising monomers copolymerizable with the above-mentioned unsaturated isocyanate, and (4) a peroxide.

[Effect]

In the composition of the present invention, the oligomer is grafted to a polymer constituting an aqueous emulsion using an isocyanate group in the oligomer, and then the (
It is presumed that the meth)acryloyl groups polymerize with each other or copolymerize with monomers, resulting in crosslinking of the polymers, resulting in curing.

The configuration of the present invention will be explained in detail below.

The aqueous emulsion used in the present invention refers to a commonly known aqueous dispersion of a polymer, and the monomers constituting the polymer component are not particularly limited, and include, for example, ethylene and vinyl acetate.

Vinyl propionate, methacrylic esters such as methyl methacrylate, acrylic esters such as ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, etc., acrylonitrile, styrene, chlorostyrene, vinyltoluene, vinyl chloride, hnylidene chloride, acrylamide. , methylol acrylamide, 2-hydroxyethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl acrylate, acrylic acid, methacrylic acid, itaconic acid, butadiene, chloroprene, isobutylene, isoprene, and the like.

Of the aqueous emulsions containing the above monomers as polymer components, in the present invention, functional groups reactive with the isocyanate groups of unsaturated isocyanates, such as hydroxyl groups, cartilage groups, etc. It is preferable to use an emulsion of a polymer having a functional group such as a xyl group or an acid amide group, or an emulsion using polyvinyl alcohol, water-soluble cellulose esters, or the like as a retention colloid.

The unsaturated isocyanate oligomer used in the present invention has 1 equivalent or less of isocyanate group and 1 equivalent of isocyanate group in one molecule.
It contains an equivalent or more of an acryloyl group or a methacryloyl group [hereinafter abbreviated as a (meth)acryloyl group], and one example thereof is the one represented by the following formula.

[However, n is 1 to 5] In the present invention, the unsaturated isocyanate olico-9mer has the role of increasing the adhesive strength of the composition and improving the water resistance and heat resistance of the film.

When using an oligomer containing more than 1 equivalent of isocyanate groups per molecule, or when using an oligomer containing less than 1 equivalent of (meth)acryloyl groups per molecule, a short time after mixing is used. There is a tendency to group together,
Storage stability may not be sufficient.

Various types of unsaturated isocyanate oligomers are known, but from a practical standpoint, an unsaturated monoalcohol containing a (meth)acryloyl group and an oligomer having an incyanate group at both ends (having a hydroxyl group at both ends) It is preferable to use one synthesized by an addition reaction between 1 mol of oligomer and 2 mol of polyvalent isocyanate (reaction product).

Examples of the unsaturated monoalcohol containing a (meth)acryloyl group include 2-hydroxyethyl acrylate, 2
-Hydroxyethyl acrylate, trimethylol diacrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, trimethylol dimethacrylate, and the like.

Examples of oligomers having isocyanate groups at both ends include polyether glycols such as I-lyethylene glycol, polypropylene glycol, and polybutylene glycol, polyester glycols having hydroxyl groups at both ends, and 1 mole of 2,4-tolylene diisocyanate. 2,6-tolylene diisocyanate, 2.4
-) Mixture of lylene diisocyanate and 2.6-) lylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, paraphenylene diisocyanate, xylylene diisocyanate, inholone diisocyanate , 1,6-hexamethylene diisocyanate, hydrogenated xylylene diisocyanate and the like.

The unsaturated isocyanate oligomer used in the present invention contains 1 to 1.8 mol, preferably 1 mol, of an unsaturated monoalcohol containing a (meth)acryloyl group per mol of the oligomer having isocyanate groups at both ends. ~1.
It is produced by reacting within the range of 4 moles.

Unsaturated isocyanate oligomers can be synthesized in monomers such as acrylic esters, methacrylic esters, styrene, aromatic vinyl compounds such as vinyltoluene, in solvents such as ethyl acetate, methyl ethyl ketone, dioxane, or in dibutyl phthalate, dioctyl phthalate,
A method in which an unsaturated monoalcohol containing a (meth)acryloyl group is added dropwise to an oligomer having an isocyanate group at both ends in a plasticizer such as diethyl acrylate phthalate, resulting in an addition reaction, can be used as is in a monomer solution, solvent solution, or plasticizer. Although it is convenient because it can be used as a solution, it is also possible to react an oligomer having an isocyanate group at both ends with an unsaturated monoalcohol having a (meth)acryloyl group without using a monomer, solvent, or plasticizer. . At this time, it is preferable to use a urethanization catalyst such as a tertiary amine or an organic compound of tin.

The unsaturated isocyanate oligomer used in the present invention does not necessarily have equimolar amounts of isocyanate groups and (meth)acryloyl groups. For example, 1 mol of an oligomer having isocyanate groups at both ends and 1 to 1.8 mol of an unsaturated monoalcohol having a (meth)acryloyl group.
Any compound containing 1 equivalent or less of isocyanate group and 1 equivalent or more of (meth)acryloyl group in one molecule may be used. For example, using 2-hydroxyethyl methacrylate as an unsaturated monoalcohol having a (meth)acryloyl group, the reaction product is produced by the reaction with 2 moles of polyethylene glycol 17-2,4-tolylene diisocyanate as an oligomer having isocyanate groups at both ends. For example, when a reaction is carried out using a compound, a mixture of monomethacrylate and dimethacrylate is produced, but this mixture may be used in the present invention.

^ Hee ↓ The above-mentioned mixture of unsaturated isocyanate oligomers containing dimethacrylate improves the curing speed of a film formed from an aqueous emulsion, and improves the hardness and adhesive strength of the cured film (especially water-resistant adhesive strength). ), etc., but also protects free isocyanate groups and increases the reaction between the isocyanate groups and the polymer constituting the aqueous emulsion.

The amount of unsaturated isocyanate oligomer to be added varies depending on the purpose of use of the composition, so it cannot be determined in general.
Generally, 3 to 200 parts by weight, preferably 5 to 150 parts by weight, per 100 parts by weight of the solid content (resin content) of the aqueous emulsion.
A range of parts by weight is appropriate. If the amount of unsaturated isocyanate is less than 3 parts by weight, the effect of the addition is small, and if the amount of unsaturated isocyanate is more than 200 parts by weight, no effect can be observed by increasing the amount.

The monomers copolymerizable with the unsaturated isocyanate used in the present invention are not particularly limited,
Depending on the type of aqueous emulsion used, either hard or soft emulsions can be used.

Practically preferred copolymerizable heptamers include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate), 1-butyl methacrylate, and 2-butyl methacrylate.
Ethylhexyl methacrylate, nonyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, phenoxyethyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, 2
-Ethylhexyl acrylate, hensyl acrylate, phenoxyethyl acrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, 1,6-hexanethiol dimethacrylate, trimethylolzoronoguntri Examples thereof include (meth)acrylic acid esters such as methacrylate and trimethylolpronoethylene acrylate, and aromatic vinyl compounds such as styrene and vinyltoluene. Two or more of these monobues may be used in combination. Further, as mentioned above, the monomers may be added in advance during the synthesis of the unsaturated isocyanate oligomer, or may be added during the preparation of the curable composition, but the monomers may be added during the synthesis of the unsaturated isocyanate oligomer. It is preferable to add it in advance during the synthesis of the unsaturated isocyanate oligomer because it facilitates the synthesis of the unsaturated isocyanate oligomer and improves its storage stability.

The combined use of monomers does not merely improve the storage stability of the unsaturated isocyanate oligomer, but has the advantage of improving physical properties such as adhesive strength.

The blending amount of the monomers is 0 to 150 parts by weight, or within the overlap of 0 to 100 parts by weight, based on 100 parts by weight of the unsaturated isocyanate oligomer.

When the amount of monomers is more than 150 parts by weight,
The effect of blending the unsaturated isocyanate is diminished, and it tends to be difficult to improve the physical properties of the cured product, such as the adhesion.

Peroxides used in the present invention include, apart from hydrogen peroxide, methyl ethyl methone oxide,
Cyclohexanone peroxide, methyl isobutyl ketone iJ? -Ketone iJ such as oxide? -Oxides,
Kymen Hydrono J? -oxide, hydro/# such as t-butyl hydroperoxide, t-
Butyl A? -oxido 2-ethylhexoate etc.
-oxyesters, penzoylno-oxide, lauroyl/goxyoxide, 2,5-dichlorobenzoyl A? Examples include organic peroxides such as acyl peroxides such as -oxide.

These peroxides exhibit sufficient curing action even when used alone; for example, acyl peroxides (benzoyl/gu-oxide) are used to add isocyanate groups to both ends during the synthesis of unsaturated isocyanate oligomers. When an aromatic isocyanate-containing oligomer is used as the oligomer, it cures relatively quickly without using a curing accelerator. It is preferable to use the agent together. For example, when using an organic peroxide, especially a hydroperoxide (cumene hydroperoxide) as the organic peroxide, using this in combination with a curing accelerator of cobalt naphthenate not only accelerates curing, but also It has a long pot life and is convenient to use.

The amount of peroxide added is 0.1 parts by weight per 100 parts by weight of the aqueous emulsion, the solid content (resin content) of the unsaturated isocyanate oligomer, and the total amount of copolymerizable monomers.
A suitable range is 10 parts by weight, preferably 0.5 to 5 parts by weight. If the amount of peroxide blended is less than 0.1 parts by weight, the curing properties at room temperature will be insufficient.On the other hand, if the amount of peroxide blended is more than 10 parts by weight, the effect of increasing the amount will be reduced. This method has the drawbacks of not only unnecessary joints but also high costs and deterioration of the physical properties of the cured product.

When a curing accelerator is used in combination with a peroxide, the amount of curing accelerator used is 100 parts by weight of the aqueous emulsion, the solid content (resin content) of the unsaturated isocyanate oligomer, and the total weight of the copolymerizable monomers. It is desirable that the amount is 0.01 to 10 parts by weight, preferably 0.1 to 2 parts by weight.

The curable composition of the present invention is prepared by uniformly mixing an aqueous emulsion, an unsaturated isocyanate oligomer, a copolymerizable monomer, a peroxide, and
There is no particular restriction on the order of addition of each component. When a peroxide is used together with a curing accelerator, the curing accelerator may be blended with the unsaturated isocyanate oligomer in advance.

If necessary, an extender may be added to the curable composition of the present invention. Wheat flour, starch, defatted soybean flour, etc. can be used as the bulking agent, but among these, wheat flour and starch are given hydrophobicity by isocyanate, and furthermore, they do not gelatinize in cold water but gelatinize by heating during bonding. It is more preferable because it becomes viscous. Further, fillers can also be blended into the curable composition of the present invention.

In addition to inorganic fillers such as clay, kaolin, Merck, and calcium carbonate, organic fillers such as wood flour and walnut shell powder can also be used.

The proportion of these extenders and/or fillers varies depending on the intended use of the curable composition, but is suitably 0 to 200% by weight, preferably 0 to 150% by weight, based on the aqueous emulsion. Further, these extenders and fillers may be used alone, or several types thereof may be used in combination.

Furthermore, a surfactant can be used at the same time in the curable composition of the present invention. The use of a surfactant is effective in preventing foaming of the curable composition, preventing settling of emulsion particles, and improving mold releasability during use. As the surfactant used, it is effective to use anionic surfactants, nonionic surfactants, or a suitable combination of both surfactants.

The amount of surfactant to be blended is 0.0% relative to unsaturated isocyanate.
1 to 15% by weight is suitable.

Furthermore, compounds of polyvalent metals can be used in the curable composition of the present invention. What are these polyvalent metal compounds?
It is a salt of a group metal cation oxide, hydroxide, or inorganic acid, and has the effect of improving the water resistance of the curable composition by causing an ion or chelate reaction with the polar group contained in the aqueous emulsion. are doing.

If a large amount of water-soluble compounds among these polyvalent metal compounds is added to the curable composition, the polymer in the aqueous emulsion will be salted out and the aqueous emulsion will easily break.

Therefore, the amount added must be kept small. on the other hand,
Those with low solubility in water can be added in large amounts to aqueous emulsions and are expected to improve the water resistance of the curable composition, and are also effective as fillers, so it is desirable to use them. The water-insoluble polyvalent metal compound is 1 to 4 parts by weight of the polymer constituting the aqueous emulsion.
00 parts by weight, preferably 5 to 200 parts by weight.

Furthermore, the curable composition of the present invention may contain an organic acid or an inorganic acid. As the organic acid or inorganic acid, in addition to ordinary acids, any one that lowers the - content of the system, such as salts that exhibit acidity when dissolved in water, are preferred, but among these, oxycarcinic acid is the most preferred.

By blending an organic acid or an inorganic acid into the curable composition of the present invention, the water resistance is improved, the water resistance changes little over time, the viscosity is stabilized, and no ruching occurs. It becomes difficult. Therefore, the usage time of the curable composition of the present invention can be extended. These can be used alone or in combination of two or more.

Although even a small amount of organic acid can produce a certain effect,
A particularly remarkable effect is that the pH of the curable composition is 2.0~
An amount of about 2.5 is obtained.

Furthermore, the curable composition of the present invention contains a highly hygroscopic compound,
For example, deliquescent inorganic salts, polyhydric alcohols, Cal? It is possible to incorporate salts such as salts. Among these, deliquescent inorganic salts and polyhydric alcohols are particularly suitable as hygroscopic compounds, and the amount added is such that the proportion of the curable composition including water is 0.
．． 1 to 10% by weight, but a particularly preferred range is 0.5 to 5% by weight.
Weight%.

By adding a highly hygroscopic compound to the curable composition as described above, when the curable composition of the present invention is used as an adhesive, the drying of the adhesive liquid after applying the adhesive to an adherend can be improved. This not only eliminates adhesion defects caused by delayed adhesion during on-site work, but also allows for measures beneficial to adhesion work, such as reducing the amount of adhesive applied, enabling high-temperature adhesion work, and increasing adhesive concentration. is possible.

Furthermore, other additives such as polymers, color formers, antifoaming agents, and fungicides may be added to the curable composition of the present invention, if necessary.

The curable composition of the present invention can be applied by means such as lining the substrate, spraying, and coating with a roll, but in actual use, it is preferably applied with a lining on the substrate.

Naturally, peroxide is added to the aqueous emulsion, curing accelerators are added as necessary to the mixture of unsaturated isocyanate and monomers, and each of these components is applied using a double-headed spray gun. You may.

〔Example〕

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

Example 1 Synthesis of (A) (unsaturated benzoaner) 11 7-9 rubble flasks equipped with a stirrer, a thermometer with a gas inlet tube, a dropping funnel, and a reflux condenser 2.4-
Tolylene diisocyanate 174!9 (1 mol), methyl methacrylate 100g, diptyltin dilaure) 0
．． 3.9, diethylene glycol 53g (0,
5 mol) was added dropwise. Subsequently, 79 g (0.55 mol) of 2-hydroxyzorobyl methacrylate in which 0.04 I of rosebenzoquinone was dissolved was added dropwise under a dry air atmosphere. Since the temperature rose with the dropwise addition, it was cooled once it reached 60°C, and the temperature was maintained thereafter.

After the dropwise addition was completed, the reaction was carried out at 60° C. for 3 hours, and as a result of infrared analysis, it was determined that the free hydroxyl groups had disappeared. Light yellowish brown, unsaturated isocyanate with a viscosity of 1.5 poise (
A solution containing 2466% by weight of methyl methacrylate was obtained.

Polyvinyl acetate emulsion containing polyvinyl alcohol (manufactured by Showa Kobunshi Co., Ltd., Polysol contact 1200, viscosity 200 days, Pl-14,O, MF'T 10°C,
3 parts by weight of benzoyl d'-oxide (50% DOP paste) was added to 100 parts by weight (solid content: 52% by weight), and the mixture was uniformly stirred and mixed to obtain a polyvinyl acetate emulsion 0).

200 parts by weight of polyvinyl acetate emulsion (A) and 50 parts by weight of unsaturated benzoanor (A) were mixed with stirring. No foaming was observed, and the surface of the mixture remained dry even after it was left overnight, but the inside was cream-like, with only a slight increase in viscosity.

In the adhesion test using birch material, the normal compressive shear force was 2
The adhesive showed an excellent adhesive strength of 30 kgf 7cm2, a wood breakage rate of 75 inches, and a compressive shearing force of 185 kgf 7cm2 after the water resistance test.

On the other hand, when unsaturated isocyanate (4) is not used and only polysol 1200 is used, the normal compressive shear force is 235
kgf 7cm2. The wood breakage rate was 40 inches, and the compressive shear force after the water resistance test was 125 kgf 7 cm2.

Example 2 Ethylene-vinyl acetate copolymer resin emulsion containing polyvinyl alcohol (manufactured by Showa Kobunshi @), EVA A
D-5, viscosity 30 $i, e, P)'14~6, MFT
0°C, solid content 56%) to 100 parts by weight of calcium carbonate (
Manufactured by Nitto Funka Co., Ltd., MS-100, average particle size 2.1
2μ), 55 parts by weight of water, and 3 parts by weight of cumene hydrochloride and monooxide were added and mixed uniformly to obtain an ethylene-vinyl acetate copolymer resin emulsion (b).

0.4 parts by weight of copal naphthenate was added to 100 parts by weight of unsaturated isocyanate (4), and 25 parts of saliva was added to 100 parts by weight of emulsion (2) and stirred uniformly.

In the adhesion test using birch material, the normal compressive shear force was 16
8 kgf 7cm2. The wood breakage rate was 25 cm, and the compressive shear force after the water resistance test was 125 kgf 7 cm2.

On the other hand, EVAA without using unsaturated isocyanate
In the case of D-5 only, the normal compressive shear force is 153 kgf
/crn2, the wood breakage rate was 0 cm, and the compressive shear force after the water resistance test was 51 k17 f 7 cm 2.

Example 3 Synthesis of unsaturated isocyanate (B) Inphoron diisocyanate 222! (1 mol), 100 # of trimethylol-trimethacrylate, and 0.3 g of dibutyltin dilaurate were added, and 45.9 (0.5 mol) of 1,4-butanediol was added dropwise. Subsequently, 2-hydroxyglobyl acrylate 789 (0.0
, 6 mol) was added dropwise. As the temperature rises as the dripping occurs,
Once the temperature reached 0°C, it was cooled and the temperature was maintained thereafter.

After the dropwise addition was completed, the reaction was carried out at 60° C. for 3 hours, and as a result of infrared analysis, it was determined that the free hydroxyl groups had disappeared. Unsaturated isocyanate CB, pale yellow, viscosity 1.8 poise)
() Rimethylol norono and Trimethacrylate) 22.
A solution containing 5% by weight) was obtained.

Modified styrene/butatsuene latex (Shiraki Zeon (
Co., Ltd. MNi pol LX 430, latex viscosity 110 centipoise, pH 6.0, average particle size 0915
μ, total solids content 49%) 100 parts by weight of benzoyl
3 parts by weight of oxide (50% by weight DOP paste) was added and mixed by stirring uniformly to obtain a modified styrene-butadiene latex C.

A liquid containing 0.1 part of accelerator D (manufactured by Showa Kobunshi (2) Co., Ltd., main component dimethylaniline) was added to 20 parts by weight of modified styrene-butadiene latex T9100 parts by weight and unsaturated benzoanor (B) was stirred. Mix evenly.

No foaming was observed in the mixture, and after one night, the water evaporated and the surface became dry, but the internal water-containing portion remained fluid with almost no increase in viscosity.

In the adhesion test using birch material, the normal compressive shear force was 14
5 kgf 7cm2, compression shear force after water resistance test is 8
It was 5kgf/crn2. On the other hand, when unsaturated isocyanate (B) was not used, the normal compressive shear force was 85 kg f 7 cm 2 and the compressive shear force after the water resistance test was 28 kg f 7 cm 2 .

*The test method for compressive shear force was conducted based on JIS K 6852.

〔Effect of the invention〕

The composition of the present invention hardly progresses in curing while water is present, and hardens only after the water is removed by dehydration or evaporation, so it has a long pot life and good workability. In addition, it increases the hardness of the film formed from the aqueous emulsion, improves solvent resistance and creep resistance, and has extremely good adhesion to substrates, making it useful as paints and adhesives.

Claims (1)

[Scope of Claims] 1) (1) an aqueous emulsion; (2) an unsaturated isocyanate oligomer containing 1 equivalent or less of isocyanate group and 1 equivalent or more of acryloyl or methacryloyl group in one molecule; and (3) ) A curable composition comprising peroxide. 2) (1) an aqueous emulsion, (2) an unsaturated isocyanate oligomer containing one equivalent or less of isocyanate group and one equivalent or more of acryloyl group or methacryloyl group in one molecule, (3) the above unsaturated isocyanate and A curable composition comprising copolymerizable monomers and (4) a peroxide.