JPH0892455A - Aqueous polymer emulsion - Google Patents

Abstract

(57) Abstract: An object of the present invention is to provide a one-pack type aqueous polymer emulsion excellent in coating film performance and storage stability, a method for producing the same, and the aqueous polymer emulsion. It is to provide a coating composition. SOLUTION: Isocyanate functional type α, β-unsaturated ester represented by the general formula (I), or isocyanate functional group α, having an isocyanate group protected by a protecting group, represented by the general formula (II), Aqueous Polymers Containing Isocyanate Functional Copolymers Comprising Units Derived From One or More .beta.-Unsaturated Esters and Units Derivable from Free Radical Polymerization Polymerizable Vinyl, Acrylate, and / or Methacrylate Monomers The above problems can be solved by using an emulsion and an aqueous polymer emulsion comprising a self-crosslinking isocyanate functional group-type core / shell copolymer using the isocyanate functional group-type copolymer.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an aqueous polymer emulsion, a method for producing the same, and a coating composition containing the polymer emulsion.

[0002]

Reaction of polyisocyanates with low molecular weight and polymeric compounds containing hydroxyl, carboxyl and / or amine groups and having at least one active hydrogen atom in the molecule is used for preparing polyurethanes. It is an important synthetic reaction and can be used in a wide variety of industrial applications.

These reactions are also very important for the preparation of crosslinkable coating compositions containing, for example, a polymer having hydroxyl functional groups and polyfunctional isocyanates in an organic solvent mixture. The great advantage of these coating compositions lies in the low crosslinking temperature range of 20-100 ° C. At this temperature, these coating compositions very rapidly form coatings with excellent chemical and mechanical resistance.

However, since the polyisocyanate shows high reactivity to a compound containing a hydroxyl group, a carboxyl group and / or an amino group and moisture in the atmosphere, these coating compositions are used as a two-component paint. Only used. However, one of the polyisocyanates, diisocyanate, is hygienic because of the fact that it is volatile, toxic to the lungs, irritating the mucous membranes and in some cases carcinogenic.

On the other hand, polyisocyanates such as dimerization and trimerization reaction products of diisocyanates containing isocyanate groups are also not preferable when the diisocyanate monomer remains. For hygiene and environmental protection, prepare a coating composition in which the isocyanate groups are present in a polymer-bonded form so that the isocyanate can lose its volatility and reduce the lung toxicity of the coating composition. There is also a desire to do so, and due to the environment and cost, attempts have been made to replace the organic solvent in the paint as much as possible with water.

At first glance, the high reactivity of isocyanate compounds with water makes it impossible to formulate aqueous polyurethane coatings. Nevertheless, attempts have been made to produce polyurethane paints with very good properties which are produced by carbamate groups even in water systems.

Aqueous polyurethane dispersions have been successfully prepared, for example, by dispersing in water a polyurethane having a hydrophilic group or an ionic group prepared in a solution of an organic solvent or a melt thereof and removing the organic solvent. it can. However, such products are no longer free of N
No CO group is included.

[0008] Such dispersions find numerous applications in the finishing of paper, fibers and leather, but suffer from a lack of solvent resistance due to inadequate cross-linking. It can also crosslink with melamine or epoxy resins at high temperatures above 120 ° C, but such coatings are only suitable for limited applications. A survey of such dispersions can be found in "Progress of Organic Coatin
gs, vol. 9, pp. 281-340, 1981 ".

Certain unsaturated monoisocyanates, which can be polymerized by free radical polymerization, can also be incorporated into the aqueous polymer emulsion. For example, RWDext
er, R. Saxon and DEFiori, "J. Coatings Techno
logy, vol. 58, no. 737, pp. 43-47, 1986 ", m
It describes the formation of a copolymer emulsion consisting of isopropenyl-α, α-dimethylbenzyl isocyanate (m-TMI) and acrylic and methacrylic acid esters.

Such aqueous emulsions containing 10 to 20 mol% m-TMI have good storage stability and only a slight decrease in NCO content over the course of weeks. After the addition of the organotin catalyst, the aqueous emulsion crosslinks with low molecular weight polyols such as trimethylolpropane to give solvent resistant coatings.

[0011]

The problem to be solved by the invention is to provide a one-pack type aqueous polymer emulsion excellent in coating film performance and storage stability, a method for producing the same, and the aqueous polymer emulsion. Another object of the present invention is to provide a coating composition containing

[0012]

[Means for Solving the Problems] In order to solve the above-mentioned problems, as a result of diligent research conducted by the present inventors, general formula (I)

[0013]

[Chemical 13] (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄
May be the same or different, and in each case, it is an alkyl group having 1 to 4 carbon atoms. ) Α, β
It has been found that unsaturated isocyanate functional type esters are capable of forming stable aqueous copolymer emulsions.

That is, the present invention has the general formula (I)

[0015]

Embedded image (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄ may be the same or different, In any case, it is an alkyl group having 1 to 4 carbon atoms.)

Units 1-9 derived from one or more isocyanate-functionalized α, β-unsaturated esters of
9% by weight, one or more vinyl monomers that can be polymerized by free radical polymerization and do not react with isocyanate groups,
An isocyanate functional group-type copolymer comprising 99 to 1% by weight of a unit derived from an acrylate monomer and / or a methacrylate monomer, wherein the solid content of the polymer emulsion is 5 to 50% by weight. Is an aqueous polymer emulsion.

The present invention also has the general formula (II)

[0018]

[Chemical 15] (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄ may be the same or different, In any case, it is an alkyl group having 1 to 4 carbon atoms, and X is a protonic acid compound residue that reacts with an isocyanate group.)

1 to 99% by weight of a unit derived from one or more α, β-unsaturated ester having an isocyanate group protected by a thermally reversible protecting group represented by Polymer emulsion containing a polymerisable, isocyanate-functional copolymer of 99 to 1% by weight of units which are not reactive with isocyanate groups and are derived from one or more vinyl, acrylate and / or methacrylate monomers. It is an aqueous polymer emulsion characterized by having a solid content of 5 to 50% by weight.

The present invention further relates to the general formula (I)

[0021]

[Chemical 16] (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄ may be the same or different, 1 to 50% by weight of a unit derived from one or more isocyanate functional type α, β-unsaturated ester represented by (C 1 to C 4 alkyl group). A core (A) consisting of 99-50% by weight of units derived from one or more vinyl monomers, acrylate monomers and / or methacrylate monomers, which are polymerizable with

Units derived from one or more vinyl, acrylate and / or methacrylate monomers having active hydrogen atoms in the molecule 5 to 35% by weight
And a shell (B) consisting of 95-65% by weight of units free of isocyanate groups and polymerizable by free-radical polymerization derived from one or more vinyl, acrylate and / or methacrylate monomers
Consists of and

The equivalent ratio of active hydrogen atoms to isocyanate groups is 0.5 to 2, and the core / shell weight ratio is 2.
An aqueous polymer emulsion containing a self-crosslinking isocyanate functional core / shell copolymer having a solid content of 0:80 to 70:30 and a solid content of 5 to 50% by weight. is there.

The present invention also has the general formula (II)

[0025]

[Chemical 17] (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄ may be the same or different, In any case, it is an alkyl group having 1 to 4 carbon atoms, and X is a protonic acid compound residue that reacts with an isocyanate group.)

1 to 50% by weight of a unit derived from one or more α, β-unsaturated ester having an isocyanate group protected by a thermally reversible protecting group represented by Self-comprising of 95 to 30% by weight of units derived from one or more vinyl monomers, acrylate monomers and / or methacrylate monomers, which are polymerizable by free radical polymerization, and one or more monomers having active hydrogen atoms. A cross-linkable isocyanate functional group type copolymer is included, the equivalent ratio of active hydrogen atoms to isocyanate groups is 0.5 to 2, and the solid content of the polymer emulsion is 5 to 50% by weight. It is an aqueous polymer emulsion.

The present invention also has the general formula (II)

[0028]

[Chemical 18] (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄ may be the same or different, In any case, it is an alkyl group having 1 to 4 carbon atoms, and X is a protonic acid compound residue that reacts with isocyanate.)

1 to 50% by weight of a unit derived from one or more α, β-unsaturated ester having an isocyanate group protected by a thermally reversible protecting group represented by A core (A) consisting of 99-50% by weight of units derived from one or more vinyl, acrylate and / or methacrylate monomers which are free radically polymerizable.

Units derived from one or more vinyl, acrylate and / or methacrylate monomers having active hydrogen atoms in the molecule 5 to 35% by weight
And a shell (B) consisting of 95-65% by weight of units free of isocyanate groups and polymerizable by free-radical polymerization derived from one or more vinyl, acrylate and / or methacrylate monomers
Consists of and

The equivalent ratio of active hydrogen atoms to isocyanate groups is 0.5 to 2, and the core / shell weight ratio is 2.
An aqueous polymer emulsion containing a self-crosslinking isocyanate functional core / shell copolymer having a solid content of 0:80 to 70:30 and a solid content of 5 to 50% by weight. is there.

The present invention further provides that the units derived from one or more vinyl, acrylate and / or methacrylate monomers having one or more active hydrogen atoms in the molecule do not react with 5 to 35% by weight of isocyanate groups.
A core (A) consisting of 95-65% by weight of units derived from one or more vinyl monomers, acrylate monomers and / or methacrylate monomers, polymerisable by free radical polymerization, and a general formula (II)

[0033]

[Chemical 19] (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄ may be the same or different, In any case, it is an alkyl group having 1 to 4 carbon atoms, and X is a protonic acid compound residue that reacts with isocyanate.)

One or more different α, β having an isocyanate group protected by a thermally reversible protecting group represented by
1-50% by weight of units derived from unsaturated esters
And a shell (B) consisting of 99-50% by weight of units derived from one or more vinyl monomers, acrylate monomers and / or methacrylate monomers, polymerisable by free radical polymerization,

The equivalent ratio of active hydrogen atoms to isocyanate groups is 0.5 to 2, and the core / shell weight ratio is 1:
An aqueous polymer emulsion containing a self-crosslinking isocyanate functional core / shell copolymer having a solid content of 10 to 10: 1 and a solid content of 5 to 50% by weight.

The present invention is preferably an aqueous polymer emulsion in which the isocyanate-functional α, β-unsaturated ester of the general formula (I) is in particular 2-methyl-2-isocyanatopropyl methacrylate.

The present invention also relates to an α, β-unsaturated ester represented by the general formula (II) having an isocyanate group protected by a thermally reversible protecting group, particularly 2-methyl-2.
-Isocyanatopropyl methacrylate, alcohol, phenol, ketoxime, ε-caprolactam,
Dialkyl malonate, alkyl acetoacetate and / or 2,2-dimethyl-1,3-dioxane-4,6
An aqueous polymer emulsion characterized in that it is a reaction product with at least one dione.

The present invention further relates to general formula (I)

[0039]

Embedded image (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄ may be the same or different, In any case, it is an alkyl group having 1 to 4 carbon atoms.)

1 to 99% by weight of one or more isocyanate functional type α, β-unsaturated ester represented by the formula (1) and one or more vinyl monomers and acrylates which are polymerizable by free radical polymerization and do not react with isocyanate groups. A monomer mixture consisting of 99-1% by weight of monomers and / or methacrylate monomers is emulsified in water in the presence of an emulsifier to form a pre-emulsion, which is then water-soluble at a temperature of 0-100 ° C. A method for producing an aqueous polymer emulsion, which comprises polymerizing in the presence of an initiator.

The present invention also has the general formula (II)

[0042]

[Chemical 21] (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄ may be the same or different, In any case, it is an alkyl group having 1 to 4 carbon atoms, and X is a protonic acid compound residue that reacts with isocyanate.)

1 to 99% by weight of one or more α, β-unsaturated ester having an isocyanate group protected by a thermally reversible protecting group represented by A monomer mixture consisting of 99-1% by weight of one or more vinyl monomers, acrylate monomers and / or methacrylate monomers is emulsified in water in the presence of an emulsifier to form a pre-emulsion, which pre-emulsion is then formed at a temperature of 0- A method for producing an aqueous polymer emulsion, which comprises polymerizing at 100 ° C. in the presence of a water-soluble initiator.

The present invention further relates to general formula (I)

[0045]

[Chemical formula 22] (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄ may be the same or different, In any case, it is an alkyl group having 1 to 4 carbon atoms.)

1-50% by weight of one or more isocyanate functional α, β-unsaturated ester represented by: and one or more vinyl monomer, acrylate monomer and / or methacrylate monomer polymerizable by free radical polymerization Of 50% by weight of a first monomer mixture in water in the presence of an emulsifier to form a pre-emulsion, which pre-emulsion is then formed at a temperature of 0-100 ° C. Completely polymerize in the presence of

Next, 5 to 35% by weight of at least one vinyl monomer, acrylate monomer and / or methacrylate monomer having an active hydrogen atom in the molecule, and one polymerizable by free radical polymerization which does not react with an isocyanate group. A second monomer mixture consisting of 95 to 65% by weight of the above vinyl monomer, acrylate monomer and / or methacrylate monomer is further added together with an initiator and an emulsifier to completely polymerize the second monomer mixture. A method of making a featured aqueous polymer emulsion is included.

The present invention also has the general formula (II)

[0049]

[Chemical formula 23] (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄ may be the same or different, In any case, it is an alkyl group having 1 to 4 carbon atoms, and X is a protonic acid compound residue that reacts with isocyanate.)

1-50% by weight of one or more isocyanate functional α, β-unsaturated ester having an isocyanate group protected by a thermally reversible protecting group represented by:
95-30% by weight of one or more vinyl monomers, acrylate monomers and / or methacrylate monomers, which do not react with isocyanate and can be polymerized by free radical polymerization, and one or more monomers 5-3 having active hydrogen atoms.
5% by weight of the monomer mixture is emulsified in water in the presence of an emulsifier to form a pre-emulsion and then the pre-emulsion is polymerized at a temperature of 0-100 ° C. in the presence of a water-soluble initiator. A method of making an aqueous polymer emulsion is characterized.

The present invention also has the general formula (II)

[0052]

[Chemical formula 24] (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄ may be the same or different, In any case, it is an alkyl group having 1 to 4 carbon atoms, and X is a protonic acid compound residue that reacts with isocyanate.)

1-50% by weight of one or more α, β-unsaturated ester having an isocyanate group protected by a thermally reversible protecting group represented by A first monomer mixture consisting of 99-50% by weight of the above vinyl monomers, acrylate monomers and / or methacrylate monomers is emulsified in water in the presence of an emulsifier to form a pre-emulsion and then the formed pre-emulsion. The temperature 0 to 100 ℃
Completely polymerize in the presence of a water-soluble initiator,

Next, 5 to 35% by weight of one or more vinyl monomers, acrylate monomers and / or methacrylate monomers having active hydrogen atoms in the molecule, and one which can be polymerized by free radical polymerization without reacting with isocyanate groups. A second monomer mixture consisting of 95 to 65% by weight of the above vinyl monomers, acrylate monomers and / or methacrylate monomers is further added together with an initiator and an emulsifier and the second monomer mixture is heated to a temperature of 0 to
Including a method for producing an aqueous polymer emulsion, which comprises completely polymerizing at 100 ° C.

One or more vinyl monomers having an active hydrogen atom in the molecule, 5 to 35% by weight of an acrylate monomer and / or a methacrylate monomer, and one or more vinyls which do not react with an isocyanate group and can be polymerized by free radical polymerization. A first monomer mixture consisting of monomers, acrylate monomers and / or methacrylate monomers 95-65% by weight is emulsified in water in the presence of an emulsifier to form a pre-emulsion, the pre-emulsion being formed at a temperature of 0-100 ° C. Completely polymerized in the presence of a water-soluble initiator, and then the general formula (II)

[0056]

[Chemical 25] (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄ may be the same or different, In any case, it is an alkyl group having 1 to 4 carbon atoms, and X is a protonic acid compound residue that reacts with isocyanate.)

1-50% by weight of one or more α, β-unsaturated ester having an isocyanate group protected by a thermally reversible protective group represented by A second monomer mixture consisting of 99-50% by weight of one or more vinyl monomers, acrylate monomers and / or methacrylate monomers is further added together with an emulsifier and an initiator, the second monomer mixture at a temperature of 0-100 ° C. Characterized by complete polymerization,
A method of making an aqueous polymer emulsion is included.

The present invention also contains the aqueous polymer emulsion of the present invention, a crosslinking agent having at least two or more active hydrogen atoms in the molecule, a crosslinking catalyst, and a solvent,
It includes a crosslinkable composition characterized by being crosslinked at a temperature of 100 to 180 ° C. to give a coating film having solvent resistance and acid resistance.

The present invention further contains the aqueous polymer emulsion of the present invention, a crosslinking catalyst, and a solvent at a temperature of 100.
It comprises a self-crosslinking composition characterized by being crosslinked at 180 ° C to give a solvent resistant and acid resistant coating.

The present invention will be described in more detail below. First, the essential structural features of the copolymerizable compound of the present invention are:
An isocyanate group bonded to a quaternary carbon atom, a method for synthesizing such a monomer is described in German Patent No. 4,320,084.

The present invention, as defined in the claims, is capable of polymerizing by α, β-unsaturated ester represented by the general formula (I) and free radical polymerization and reacting with an isocyanate group. The present invention provides an aqueous polymer emulsion containing an isocyanate functional group-type copolymer composed of a vinyl monomer, an acrylate monomer and / or a methacrylate monomer, a method for producing the same, and a cross-linking coating composition containing the emulsion. . here,

Chemical formula (Ia):

[Chemical formula 26]

2-Methyl-2-isocyanatopropyl methacrylate (hereinafter abbreviated as MIPMA), which is an unsaturated monoisocyanate represented by, is particularly preferable among the above-mentioned monomers. This monomer can be copolymerized in the emulsion state with an acrylate monomer, a methacrylate monomer and / or a vinyl monomer. The resulting isocyanate functional copolymer-based aqueous polymer emulsion retains the NCO content for many months without significant loss.

The stability of the isocyanate-functional copolymers used according to the invention against hydrolysis is notable for polyisocyanates in the absence of catalyst, the steric shielding of the NCO groups by the methyl groups in the α-position. Is considered to be the cause. As already mentioned above, essentially any unsaturated isocyanate of the general formula (I) is capable of forming isocyanate-functional copolymers contained in the aqueous polymer emulsion according to the invention. it can.

Examples of the unsaturated isocyanate represented by the general formula (I) which constitutes the first component of the copolymer include 2-
Methyl-2-isocyanatopropyl methacrylate (M
IPMA), 2-methyl-2-isocyanatopropyl acrylate, 3-methyl-3-isocyanatopropyl methacrylate, 2-methyl-2-isocyanatobutyl methacrylate, 2-methyl-2-isocyanatopentyl methacrylate,

Examples thereof include 3-methyl-3-isocyanatopentyl methacrylate, 4-methyl-4-isocyanatopentyl methacrylate and acrylates corresponding to these compounds. Among them, 2-methyl-2-isocyanatopropyl methacrylate (MIPMA ) Is preferred.

Compared to m-TMI, the unsaturated isocyanates of the general formula (I) used according to the invention have the particular advantage that homopolymers and conventional vinyl monomers, acrylate monomers and / or methacrylates are particularly advantageous. There is the advantage that both copolymers with monomers can be prepared.

The mixing range is not particularly limited, but the isocyanate functional group type α, β-unsaturated ester represented by the general formula (I) is 1 to 99% by weight, preferably 5 to 75% by weight, And 99% to 1% by weight, preferably 95% by weight, of vinyl monomers, acrylate monomers and / or methacrylate monomers which can be polymerized by free radical polymerization.
~ 25% by weight.

A further advantage is that the homopolymer of the compound of formula (I) has a high ceiling temperature (which corresponds to the ceiling temperatures of other methacrylates) and has a favorable glass transition temperature. is there. MIPMA
In the case of the homopolymer of 1., the glass transition temperature is 95 ° C. For this reason, the unsaturated isocyanates of the general formula (I) used according to the invention are advantageous compared to commercially available m-TMI.

As an α-methylstyrene derivative, m-TMI is subject to the same limitations as this monomer in terms of copolymerizability with other monomers and maximum polymerization temperature. A further disadvantage of commercially available m-TMI is that the glass transition temperature of the homopolymer is calculated from the copolymer:
146 ° C. (determined by the method of Dexter et al.). This has a certain isocyanate monomer content and is an attendant drawback with respect to the selection and composition of the monomers to achieve a particular glass transition range.

Other components of the isocyanate functional group-type copolymer contained in the polymer emulsion according to the present invention include vinyl monomers, acrylate monomers and / or vinyl monomers which are polymerizable by free radical polymerization and do not react with isocyanate groups. Or there is a methacrylate monomer.

Specific examples thereof include styrene, vinyltoluene, methyl acrylate, ethyl acrylate, n
-Butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, stearyl acrylate,
Methyl methacrylate, ethyl methacrylate, n- and iso-butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate,

Mention may be made of acrylates and methacrylates having alkoxypolyethylene glycol side chains with 2 to 12 ethylene oxide repeating units, and N-vinylpyrrolidone. These can be used alone or as a mixture with isocyanate-functional monomers.

The present invention containing an unsaturated isocyanate represented by the above-mentioned general formula (I) and a copolymer of a vinyl monomer which does not react with an isocyanate group, an acrylate monomer and a methacrylate monomer, which is polymerizable by free radical polymerization. Advantageously, the aqueous polymer emulsion of 5 has a solids content of 5 to 50% by weight, preferably 20 to 35% by weight.

The isocyanate functional group-type copolymer contained in the polymer emulsion of the present invention is basically capable of polymerizing the α, β-unsaturated ester represented by the general formula (I) by free radical polymerization. It is prepared by reacting with another monomer. The monomer mixture is an α, β-unsaturated ester represented by the general formula (I) in an amount of 1 to 99% by weight, preferably 5 to 75% by weight, a vinyl monomer which is polymerizable by free radical polymerization and does not react with an isocyanate group, It is composed of 99-1% by weight, preferably 95-25% by weight, of one or more monomers from the group consisting of acrylate and methacrylate monomers.

The above monomer mixture is emulsified in water in the presence of anionic and / or nonionic emulsifiers to form a pre-emulsion, then the pre-emulsion is polymerized in the presence of a free radical initiator and optionally a chain regulator. Let This pre-emulsion is prepared by using an aqueous emulsifier solution through which nitrogen gas is passed and increasing the stirring speed in a nitrogen atmosphere to stir, that is, disperse the monomer mixture in the solution.

After forming a stable oil-in-water (O / W) emulsion (pre-emulsion), the initiator and the chain regulator are added. The mixture is heated with stirring to a temperature of 40-100 ° C. under a nitrogen atmosphere. In this way, the polymerization starts immediately and is completed within 2 to 4 hours.

The solids content of the resulting polymer emulsion is 5 to 50% by weight, preferably 20 to 35% by weight. Using this procedure, the amount of aggregates is less than 1% by weight, typically less than 0.1% by weight. The choice and amount of emulsifier is important for the stability of the pre-emulsion and copolymer. Anionic emulsifiers have proven to be very suitable and can be used alone or in admixture with nonionic surfactants.

As an example, sodium dodecyl sulfate,
Sodium and ammonium salts of long chain fatty alcohol polyglycol ether sulphates and alkylphenol polyglycol ether sulphates (e.g. Henkel Disponil FES77 and Disponil).
AES 21), and dioctyl sodium sulfosuccinate and tetrasodium N- (1,2-dicarboxyethyl) -N-octadecyl sulfosuccinate (Americ)
There are sodium sulfosuccinates, such as Aerosol 22) from An Cyanamid.

The emulsifier is used in an amount of 0.1 to 5%, based on the monomer, in order to obtain a stable emulsion of the polymer. Nonionic emulsifiers such as fatty alcohol polyglycol ethers and alkylphenol polyethylene glycol ethers are added as stabilizers in an amount of 0.1 to 2% based on the total emulsion and are preferably added only after the completion of polymerization.

Specific examples of such emulsifiers include Tr
iton X-100 (made by Rohm & Haas),
Disponil NP 307 (manufactured by Henkel), decaethylene glycol hexadecyl ether (Brij 56, manufactured by Atlas Powder) and, for example, Pluronic L 61 and F 68.
There are polyethylene oxide / polypropylene oxide block copolymers such as (manufactured by BASF).

The choice and amount of emulsifier also depends on the polymerized NCO.
There is a considerable effect on the stability of the group against hydrolysis. This can be illustrated by using a MIPMA copolymer emulsion as a specific example. For example, with 3% by weight of the preferred sodium dodecyl sulfate, MIPMA14.
After emulsion polymerization of a monomer mixture containing 6% by weight, 93.4% by weight of the amount of isocyanate used can still be detected after polymerization by isocyanate titration according to DIN 53185, this value being obtained using 2% of said emulsifier. The hour is only 88.2%. Further, at 2.3% by weight, the amount of aggregates increased four times.

On the other hand, when 2% of Aerosol 22 was used, only 60% of the isocyanate content was still detected and the amount of aggregate was 0.7% by weight. This emulsifier has a much higher HLB value than sodium dodecyl sulphate (HLB = 40), so the MIP during polymerization
The hydrolysis of the MA monomer also depends on the HLB value of the emulsifier.

Further, the composition of the unreacted portion of the monomer also affects the stability of the polymerized NCO group against hydrolysis.
For example, the addition of 5 to 25% by weight of long chain acrylates or methacrylates such as lauryl or stearyl acrylates or methacrylates increases stability to hydrolysis due to hydrophobic interactions.

Suitable initiators for preparing the copolymers contained in the polymer emulsions of the present invention are inorganic and organic water-soluble per compounds and azo initiators. Initiators which are convenient to use are initiators which are already active at polymerization temperatures 0-70 ° C., such as redox systems consisting of one or more inorganic or organic per compounds and one or more inorganic or organic reducing agents. is there.

An inorganic per compound (eg ammonium or potassium peroxydisulfate) and an inorganic or organic reducing agent (eg Fe (II) or Ce (III) salt, sodium pyrosulfite, sodium pyrosulfate or ascorbic acid) The mixture of is particularly active. Combinations of organic hydroperoxides and peroxides (eg tert-butyl hydroperoxide, cumene hydroperoxide, benzoyl peroxide, cumene peroxide) with one or more reducing agents are also active.

Further, a water-soluble azo initiator (for example, 2,2 '
-Azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis (N, N'-dimethyleneisobutylamidine) dihydrochloride, or 2,2'-azobis (2-methylpropionamide) dihydrate) , Alone or in admixture with a redox initiator system, can initiate emulsion polymerization of the monomer mixture.

The amount of initiator required is, for example, from 0.05 to
It is 3% by weight, preferably 0.1 to 2% by weight. In order to adjust the average molecular weight of the copolymer, 0.5 to 5% by weight of a chain regulator based on the solid content may be additionally used. Suitable chain regulators are especially mercaptans, preferably tertiary SH groups, such as tert-dodecyl mercaptan.

The aqueous polymer emulsions according to the invention are suitable for preparing crosslinkable coating compositions. These compositions include the aqueous polymer emulsions of the present invention, small molecules having at least two or more active hydrogen atoms in the molecule, and / or
Or polymeric crosslinkers (eg polyols, polycarboxylic acids and polyamines), suitable crosslink catalysts and optionally other additives (eg paint pigments, UV and heat stabilizers, antiskin and antifoam agents, membranes) Formation improving solvents and organic co-solvents, and rheology modifiers).

These coating compositions have a solids content of 5-5.
It is convenient to formulate it to be 0% by weight, preferably 20-35% by weight. The proportion of the crosslinking catalyst is, for example, 0.0
It is 5 to 3% by weight. The coating composition can be formulated without the use of solvents, or one or more solvents can be added at 0.5%.
It may be contained in an amount of up to 15% by weight. These coating compositions crosslink at 100-180 ° C to form carbamate, urea and / or amide bonds to provide solvent and acid resistant coating layers.

Low molecular weight or polymeric crosslinkers having at least two active hydrogen atoms in the molecule include, for example, polyols, polycarboxylic acids and / or polyamines. Emulsions of OH-functional polyacrylate copolymers have been found to be particularly preferred crosslinkers.

The polyacrylate copolymer is a hydroxy functional type acrylic acid ester or methacrylic acid ester (eg, 2-hydroxyethyl acrylate, 2
-Hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroquinpropyl methacrylate,

Acrylic acid monoesters and methacrylic acid monoesters of 4-hydroxybutyl methacrylate and polyether glycols having 2 to 10 alkylene oxide repeating units in the side chain) and other vinyl monomers, acrylate monomers and / or methacrylate monomers. It was formed.

The OH number of these particularly preferred crosslinking agents is
The amount is 5 to 100 mgKOH, preferably 20 to 50 mgKOH, per 1 g of the emulsion. The solids content of these crosslinking agents is 5 to 50% by weight, preferably 20 to 35% by weight. OH of these crosslinking agents in the coating composition of the present invention
The content is 0.1 to 2 equivalents, preferably 0.8 to 1.2 equivalents, relative to the NCO of the isocyanate functional group type copolymer.

Other potential crosslinking agents are dispersions of OH-functional copolymers containing carboxy groups and / or tertiary amine groups which are wholly or partly neutralized. Suitable crosslinking catalysts for the coating compositions of the present invention include, for example, organotin compounds such as dimethyltin diacetate, dimethyltin dilaurate, dibutyltin diacetate and dimethyltin dilaurate, and tributylamine, 1,4-diazabicyclo, for example. [2.2.
0] octane or 1,8-diazabicyclo [5.4.
0] tertiary amines such as undeca-7-ene.

Mixtures of organotin compounds and tertiary amines are also suitable as crosslinking catalysts. The proportion of the crosslinking catalyst is preferably 0.05 to 3% by weight, based on the paint (lacquer) composition. Usable as organic solvents are preferably solvents which do not react with isocyanate groups, such as aromatic hydrocarbons, esters, ketones, glycol ethers, glycol ether esters and tertiary amides. These solvents can be present in the coating (lacquer) composition of the present invention in an amount of 0.5 to 15% by weight in order to improve film formation.

Depending on its application to metallic or non-metallic substrates, the coating compositions according to the invention are crosslinked at temperatures from room temperature to 180 ° C., preferably at temperatures of 100 ° to 180 ° C., to obtain adhesion,
A solvent-resistant and acid-resistant coating film having good hardness and water resistance is obtained. Since these coating compositions have a short pot life, it is preferably used as a two-component coating composition (containing one component of an aqueous OH functional group type crosslinking agent containing an organic solvent, a crosslinking catalyst and other additives).

The emulsions according to the invention also comprise 0.5 to 3% by weight of one of the abovementioned crosslinking catalysts, 0.5 to 15% by weight of one or more organic solvents, and optionally other additives and auxiliary substances. In the presence of 80-180 without the addition of a crosslinking agent
It has been found that self-crosslinking occurs between 0 ° C and 110-160 ° C as a suitable temperature. The storage stability of these paints was 2-3 weeks at room temperature.

Further, the emulsion of the present invention can be applied to wood, paper,
It is also suitable as an adhesive for substrates containing hydroxy groups such as boards and leather. Further, the polymer of the emulsion of the present invention can be isolated as an anhydrous powder by a suitable drying method such as spray drying, vacuum drying, or freeze drying.

In a preferred embodiment of the present invention, the compound of general formula (II)

[Chemical 27] (However, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄ may be the same or different, and in each case An alkyl group having 1 to 4 carbon atoms, X is a protonic acid compound residue showing reactivity with isocyanate), and an isocyanate group having a protective group, and a vinyl monomer polymerizable by free radical polymerization. There is provided an aqueous polymer emulsion containing an isocyanate functional group-type copolymer composed of an acrylate monomer and / or a methacrylate monomer.

These aqueous polymer emulsions and the crosslinkable coating compositions prepared from them are characterized by a further increase in storage stability. When the isocyanate functional group-type copolymer contained in these polymer emulsions is prepared, the polymerizable isocyanate represented by the general formula (I) has a suitable content of one active hydrogen atom per molecule before the polymerization. Block with compound.

Suitable compounds for the thermally reversible protection of MIPMA and other unsaturated isocyanates of the general formula (I) are, for example, methylethylketoxime, phenol, ε-caprolactam, methanol, Ethanol, 2-ethoxyhexanol, dialkyl malonate, alkyl acetoacetate and 2,2-
Dimethyl-1,3-dioxane-4,6-dione may be mentioned.

Such compounds, which have active hydrogen atoms, are capable of reacting with isocyanate groups attached to quaternary carbon atoms under mild conditions to give stable polymerization to water and other nucleophiles. Giving a carbamate compound.

In the polymer, the isocyanate group protected by a protecting group depends on the protecting agent used, but is not limited to 80 to 80%.
Decomposes at 180 ° C into free NCO groups and protectants. An exception is MIPMA's methyl and ethyl carbamates, whose aqueous polymer emulsions are less volatile due to transesterification of carbamate groups and elimination of methanol or ethanol in the presence of 0.05-3% by weight of crosslinking catalyst. The OH functional group type compound is crosslinked at a low temperature of about 80 ° C. to give a coating film.

Preferred examples of the ethylenically unsaturated isocyanate having a protecting group are methyl ethyl ketoxime carbamate, and MIPMA methyl and ethyl carbamate.

Therefore, the present invention further relates to a unit 1 derived from an α, β-unsaturated ester having an isocyanate group protected by a thermally reversible protecting group represented by the general formula (II).
.About.99% by weight, preferably 5 to 75% by weight, and 99 to 1% by weight, preferably 95 to 25% by weight of a unit derived from a vinyl monomer, an acrylate monomer and / or a methacrylate monomer polymerizable by free radical polymerization.
There is provided an aqueous polymer emulsion containing an isocyanate functional group-type copolymer comprising 100% by weight.

These aqueous polymer emulsions are prepared in the same manner as described above, in combination with the copolymer derived from the α, β-unsaturated ester represented by the general formula (I). Also here, it is preferable to polymerize after forming the pre-emulsion by the above-mentioned method. As the emulsifier, the initiator, the chain regulator and the like, the same substances as described above can be used in combination with the polymer derived from the monomer represented by the general formula (I).

The polymer emulsions containing the copolymers derived from the monomers of the general formula (II) can also be used for the preparation of crosslinkable coating compositions. For example, the emulsions are polyfunctional compounds having active hydrogen atoms, such as polyols, polyamines, polyester diols and polyester polyols, and polycarbonate diols, which have active hydrogen atoms dissolved in water or dispersed in water, or dissolved in organic solvents. Can be mixed with to give a one-pack type coating composition and can be crosslinked at a temperature of 100 ° C. or higher.

Accordingly, the present invention also provides a crosslinkable coating composition containing the above-described aqueous polymer emulsion. Upon cross-linking, the isocyanate groups are reformed from the carbamate groups having polymerized protecting groups with the removal of the protecting agent, and these reformed isocyanate groups then react with the cross-linking agent containing active hydrogen atoms. It reacts to form a network structure with a carbamate bond, a urea bond or an amide bond.

Particularly preferred cross-linking agents are emulsions and dispersions of aqueous OH-functional acrylates formed from hydroxy-functional acrylates or methacrylates and other vinyl, acrylate and methacrylate monomers. And the OH number is 5 to 100 mgKOH / g of emulsion, preferably 20 to 50 mgKOH, and the solid content is 5 to 50% by weight, preferably 20 to 35% by weight.

The OH content of the cross-linking agent in these paints is based on the NCO equivalent of the protected MIPMA emulsion.
It is 0.1 to 2 equivalents, preferably 0.8 to 1.2 equivalents. As the protecting group leaving catalyst and the crosslinking catalyst, the above-mentioned organotin compounds, tertiary amines, and mixtures thereof can be used, and are used in a proportion of 0.05 to 3% by weight. The organic solvent is added in an amount of 0.5 to 1 to improve the film formation.
An amount of 5% by weight can be added to the coating composition.

Preferred organic solvents are solvents that do not react with isocyanate groups, and examples thereof include aromatics, esters, ketones, glycol ethers, glycol ether esters and amides. However, it is also possible to use highly volatile OH-functional solvents. Such solvent is evaporated off before deprotecting the carbamate.

The unsaturated isocyanate having a protecting group is
Such compounds, preferably methylethylketoxime carbamate of MIPMA in a proportion of 1 to 50% by weight, preferably 5 to 35% by weight, of vinyl monomers, acrylate monomers and methacrylate monomers which do not react with isocyanate, 95 to 30% by weight, preferably 90 ~
A mixture of 35% by weight and 5 to 35% by weight, preferably 10 to 30% by weight, of monomers containing groups with active OH groups (particularly useful compounds are compounds with OH and COOH groups). It can also be used for preparing a self-crosslinking emulsion by a method of copolymerizing in an aqueous emulsion.

Due to the inert nature of the isocyanate monomers having protecting groups, they can be polymerized from aqueous pre-emulsions with comonomers which react with isocyanates and comonomers which do not react with isocyanates, and the methods described for monomers having isocyanate functional groups. By using, it is possible to prepare a random emulsion copolymer having storage stability.

Suitable monomers having an active hydrogen atom capable of reacting with an isocyanate group formed by thermally removing a protecting group from a carbamate group include, for example,
2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, and 2-10 alkylene oxide repeating units in the side chain. OH such as acrylic and methacrylic acid monoesters of polyalkylene glycols
Functional group type acrylates and methacrylates may be mentioned.

Another embodiment of the present invention provides an aqueous polymer emulsion containing a self-crosslinking isocyanate functional core / shell copolymer. Either the core or the shell is represented by the general formula (II) containing an isocyanate functional type α, β-unsaturated ester represented by the general formula (I) or an isocyanate group protected by a protecting group. It comprises a copolymer obtained by polymerizing a monomer obtained by free radical polymerization with a vinyl monomer, an acrylate monomer and / or a methacrylate monomer.

These copolymers can be prepared by carrying out emulsion polymerization stepwise. For example, the general formula (I)
1 to 50% by weight, preferably 5 to 3
5% by weight and 99 to 50% by weight, preferably 95 to 50% by weight of vinyl monomer, acrylate monomer and / or methacrylate monomer polymerizable by free radical polymerization.
The first monomer mixture, consisting of 65% by weight, can be emulsified in water with an emulsifier to form a pre-emulsion, after which the pre-emulsion is heated to a temperature of 0-10.
It is completely polymerized in the presence of a water-soluble initiator at 0 ° C.

One or more vinyl monomers having at least one active hydrogen atom in the molecule, acrylate monomers and / or methacrylate monomers, preferably OH functional type acrylic acid ester or methacrylic acid ester polymerizable by free radical polymerization, and A second monomer mixture further comprising an unsaturated monocarboxylic acid or dicarboxylic acid, and one or more vinyl monomers, acrylate monomers and / or methacrylate monomers, which do not react with isocyanate groups and can be polymerized by free radical polymerization, is further used as an initiator. This second monomer mixture, which is added together with the emulsifier and forms a shell, is completely polymerized.

By this procedure a so-called core / shell emulsion polymer is formed and each latex particle is NCO
It consists of a core containing groups and an outer layer containing OH groups. Thus, both reactive groups are present in one latex particle, but they are spatially separated from each other.
The two groups can only react with each other at the interface between the core and the shell. In this way, both crosslinking components can be combined and present in one polymer and still achieve storage stability for several months.

Particularly in this method, the monomer represented by the general formula (I), preferably MIPMA, 1 to 50% by weight,
Preferably from 5 to 35% by weight and from 99 to 50% by weight, preferably from 95 to 65% by weight of other vinyl, acrylate and / or methacrylate monomers which are polymerizable by free radical polymerization and do not react with isocyanate groups. One monomer mixture together with 0.5 to 3% by weight of anionic or nonionic emulsifier and an initiator, preferably a redox initiator, at a temperature of 0 to 100 ° C., preferably 40 to 60 ° C., optionally the presence of a chain regulator. Polymerize underneath.

The above-mentioned substances are suitable as monomers, emulsifiers, chain regulators and initiators. The amount used should also correspond to the amount previously suggested. After the completion of the polymerization, the emulsion has a solid content of 10 to 40% by weight, preferably 15 to 30% by weight, 0.5 to 2% by weight of an emulsifier corresponding to the amount of the first stage is added, and then 5 to 30% by weight of free-radically polymerizable OH-functional monomers, preferably 10 to 25% by weight, free-radically polymerizable unsaturated acids such as acrylic acid,
Methacrylic acid or itaconic acid, 0.1-5% by weight, and vinyl monomers, acrylate monomers and methacrylate monomers 95-65 that do not react with isocyanate groups
A second monomer mixture consisting of wt.%, Preferably 85-70 wt.%, Further initiator and optionally chain regulator is added dropwise over 90 minutes.

The polymerization is carried out at the same temperature until the newly added monomer mixture has completely reacted. Suitable OH
Examples of the functional group-type monomer include acrylic acid monoesters and methacrylic acid monoesters of polyalkylene glycol having alkylene oxide repeating units 2 to 10 as side chains, as well as 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate. , 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate and the like.

OH-functional acrylates are preferred over methacrylates because they have a low polymerization rate constant and therefore slowly polymerize to the shell and accumulate in the outer layer of the shell. This increases the storage stability of the resulting emulsion and reduces the likelihood of premature reaction between the isocyanate groups in the core and the OH groups in the shell. Emulsion polymers prepared using 2-hydroxyethyl acrylate have greater stability with respect to NCO and OH groups than those polymerized using 2-hydroxyethyl methacrylate.

This procedure produces an aqueous polymer emulsion containing the core / shell emulsion polymer as previously described. The solids content of the polymer emulsion is 5 to 50% by weight, preferably 20 to 35% by weight. The weight ratio of isocyanate functional core to OH functional shell is from 20:80 to 70:30.
The range is up to. The range of this ratio is 40:60 to 6
Up to 0:40 is more advantageous. The equivalent ratio of active hydrogen atoms to NCO groups is 0.1 to 2, but 0.8 to
1.2 is more preferable.

In order to improve storage stability and film formation,
The glass transition point for the OH functional shell can be between -20 ° C and + 60 ° C. The T _g value for the core is +1
0- + 90 degreeC is preferable and + 25- + 50 degreeC is especially preferable. The T _g of the whole core / shell type emulsion copolymer of the present invention can be 0 to 60 ° C., preferably 10 to
40 ° C.

An isocyanate functional group-type copolymer core,
Active hydrogen atoms (for this purpose OH groups and COO
Such emulsion copolymers, which consist of a copolymer shell having H groups are preferred), have a wide variety of applications in water-based coatings, printing inks, adhesives and paper and fiber coatings and the like.

This emulsion copolymer comprises 0.05 or more of the above-mentioned organotin-based and tertiary amine-based crosslinking catalysts.
In the presence of ~ 3% by weight, optionally together with 0.1-15% by weight of one or more organic solvents as labeling agents, 0-1
Wide temperature range of 80 ° C, preferably 100-180
At a temperature of ° C, a film is formed and crosslinked to give a layer with good chemical, optical and mechanical properties.

In order to achieve good chemical durability,
For sufficient crosslinking, the number of NCO equivalents in the core can be matched to the number of active hydrogen equivalents in the shell,
A wide range can be tilted above or below this equivalence condition for many applications. The ratio of active hydrogen atoms to NCO groups is preferably 0.5 to 2, and particularly preferably 0.8 to 1.2.

Therefore, the present invention also provides a self-crosslinking paint (lacquer) composition containing the core / shell copolymer. These compositions may further comprise additives and auxiliary substances such as paint pigments, crosslinking catalysts, UV stabilizers, heat stabilizers and organic solvents, among others.

Thus, using the aqueous polymer emulsion containing the core / shell type copolymer of the present invention, the monomer represented by the general formula (I) or (II) and other vinyl monomer, acrylate monomer and / or Self-crosslinking emulsions can be prepared in the same manner as described above for aqueous polymer emulsions consisting of copolymers made from methacrylate monomers.

Isocyanate monomers protected with a protecting group of the general formula (II), preferably methylethylketoxime protected isocyanate monomers, are used for this purpose because they are stable to hydrolysis. In addition, it is possible to polymerize to the core as well as to polymerize to the shell. The OH content of the copolymer of such an emulsion is
0.1-2.0 equivalents relative to NCO, preferably 0.8
~ 1.2 equivalents. Further, in these copolymer emulsions, the core / shell weight ratio is 20:80 to 70: 3.
It can be 0, preferably 40:60 to 60:40.

The one-pack type baking paint contains 0.05 to 3% by weight of one or more of the above-mentioned protecting group-leaving catalyst and crosslinking catalyst, and 0.5 to 15% of one or more of the above-mentioned organic solvent, By adding pigments, other additives, and auxiliary substances,
It can be prepared from these emulsions. When applied to metal and non-metal substrates, 100-18
It crosslinks between 0 ° C, gives a glossy film, is excellent in adhesiveness, hardness and water resistance, is solvent resistant and acid resistant, and has excellent storage stability of several months at room temperature.

When MIPMA's methyl carbamates or ethyl carbamates are used as isocyanate monomers protected with protecting groups in emulsions of self-crosslinking random and core / shell copolymers, their mixture is 80%. It can be crosslinked at temperatures as low as ° C up to 180 ° C, preferably at temperatures of 100-160 ° C, without the formation of intermediates with free isocyanate groups.

Apart from the long-term stability, the advantage of the one-pack type coating composition of the present invention is that the content of volatile organic substances is small (even if the removal of the protective agent is taken into consideration), and in terms of coating technology. The property can be adjusted in a wide range (it can be realized by selecting the monomer composition and emulsion polymerization method). This allows high quality polyurethane baking coatings to be used as an aqueous one-part system, thereby providing environmental and economic advantages.

The copolymers can in all cases be removed as solids from the aqueous polymer emulsions according to the invention by drying methods such as, for example, spray drying or freeze drying. The invention is illustrated in the examples.

[0136]

EXAMPLES Example 1 In a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a gas suction tube and a thermometer, 2
Methyl-2-isocyanatopropyl methacrylate (M
IPMA) 7.3 parts, styrene 10 parts, methyl methacrylate 10 parts, 2-ethylhexyl methacrylate 6
A mixture of 2.7 parts and 10 parts 2-ethylhexyl acrylate was stirred vigorously in a solution of 214 parts deionized water, 2 g sodium dodecylsulfate, 0.6 g potassium peroxydisulfate and 0.6 g sodium metasulfite, with vigorous stirring. Further, it was dispersed while flushing with N ₂ .

The dispersion obtained is heated at 60 ° C. for 2 hours,
An emulsion having a solid content of 30.2% by weight was obtained. The NCO content determined by titration was 0.45% immediately after polymerization and 0.43% after 3 months.

Example 2 26 parts of 2-methyl-2-isocyanatopropyl methacrylate (MIPMA) and styrene were placed in a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a gas suction tube and a thermometer. 10 copies, 2-
A mixture of 54 parts ethylhexyl methacrylate and 10 parts 2-ethylhexyl acrylate was added to 21 parts deionized water.
4 parts, 2 g of sodium dodecylsulfate, 0.6 g of potassium peroxydisulfate and 0.6 g of sodium metasulfite were dispersed while flushing with N ₂ with vigorous stirring.

The dispersion obtained is heated at 60 ° C. for 2 hours,
An emulsion having a solid content of 30.1% by weight was obtained. The NCO content determined by titration was 1.52% immediately after polymerization and 1.48% after 3 months.

Example 3 26 parts of 2-methyl-2-isocyanatopropyl methacrylate (MIPMA) and styrene were placed in a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a gas suction tube and a thermometer. A mixture of 15 parts, 37 parts of methyl methacrylate, and 22 parts of n-butyl acrylate, 130 parts of deionized water, 1.8 parts of sodium dodecyl sulfate, 0.1 part of potassium peroxydisulfate.
Disperse in a solution of 7 parts and 0.17 part of sodium metasulfite with vigorous stirring while flushing with N ₂ .

The pre-emulsion obtained was heated at 60 ° C. for 2 hours. Next, to the core polymer prepared by this method,
A solution containing 1.2 parts of sodium dodecyl sulfate in 64 parts of water was added. After that, 18.7 parts of 2-hydroxyethyl methacrylate, 15 parts of styrene, 10 parts of methyl methacrylate, 27 parts of 2-ethylhexyl methacrylate, 2
An emulsion of 27.2 parts of ethylhexyl acrylate, 2 parts of acrylic acid, 0.1 g of potassium peroxydisulfate, 0.1 g of sodium metasulfite and 40 parts of deionized water was added dropwise at 60 ° C. over 20 minutes.

Subsequently, polymerization was carried out at the same temperature for another 2 hours until the solid content of the polymer emulsion reached 29.9% by weight. The NCO content was 0.84%. By this method, an aqueous polymer emulsion of core / shell type copolymer was obtained.

Example 4 8.2 parts of 2-methyl-2-isocyanatopropyl methacrylate (MIPMA) was placed in a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a gas suction tube and a thermometer. , Styrene 15 parts, methyl methacrylate 40 parts, and n-butyl acrylate 36.8 parts, a mixture of deionized water 130 parts, sodium dodecylsulfate 1.8 parts, potassium peroxydisulfate 0.17 parts and sodium metasulfite 0. Disperse in 17 parts of solution with vigorous stirring and flushing with N ₂ .

The resulting pre-emulsion was heated at 60 ° C. for 2 hours to form the core. This core polymer was then treated with 1.2 parts sodium dodecyl sulfate in 64 parts water.
A solution containing parts was added. Thereafter, 7.6 parts of 2-hydroxyethyl acrylate, 15 parts of styrene, 10 parts of methyl methacrylate, 30 parts of butyl methacrylate, 35.4 parts of butyl acrylate, 2 parts of acrylic acid, 0.1 g of potassium peroxydisulfate, 0.1 g of sodium metasulfite. 1 g
60 parts of an emulsion prepared from 40 parts of deionized water
It was added dropwise at 20 ° C. over 20 minutes.

Polymerization was subsequently carried out for 2 hours at the same temperature until the solids content of the emulsion reached 31.9% by weight to form a shell. NCO content is
It was 0.20%.

(Embodiment 5) The same apparatus as in Embodiment 1 was used, and N-
A mixture of 30 parts of (2-methacryloyloxy-1,1-dimethylethylethyl carbamate), 10 parts of styrene, 50 parts of 2-ethylhexyl methacrylate and 10 parts of 2-ethylhexyl acrylate, and 214 parts of deionized water.
Parts, 2 parts of sodium dodecyl sulfate, 0.6 parts of potassium peroxydisulfate and 0.6 parts of sodium metasulfite, with vigorous stirring and flushing with N ₂ , the dispersion is dispersed at 60 ° C. Heated for 2 hours. At that time, the solid content reached 30.2% by weight.

Example 6 (Preparation of Self-Crosslinking Aqueous Copolymer Emulsion Having Isocyanate Group Protected by Protecting Group) The same apparatus as in Example 1 was charged with N- (2-methacryloyloxy-1,1-). Dimethyl ethyl ethyl carbamate) 30 parts, styrene 10
Part, 2-ethylhexyl methacrylate 40 parts, 2-ethylhexyl acrylate 10 parts, 2-hydroxyethyl methacrylate 10 parts and tert-dodecyl mercaptan 1 part, a mixture of deionized water 214 parts, sodium dodecyl sulfate 2 parts and potassium peroxydisulfate. 0.6
Parts and 0.6 parts of sodium metasulfite, with vigorous stirring, with N ₂ flushing,
The dispersion was heated at 60 ° C. for 2 hours. The solid content at that time reached 30.8% by weight.

Example 7 (Preparation of Self-Crosslinking Core / Shell Copolymer Having Isocyanate Group Protected by Protecting Group) In the same apparatus as in Example 1, 12 parts of the reaction product of MIPMA and methylethylketoxime was used. , Styrene 15 parts, methyl methacrylate 36
Part, n-butyl acrylate 36 parts and tert-dodecyl mercaptan 1 part, deionized water 130 parts.
Parts, sodium dodecylsulfate 1.8 parts, potassium peroxydisulfate 0.17 parts and sodium metasulfite 0.1
Disperse in 7 parts of solution with vigorous stirring and flushing with N ₂ , and heat the dispersion at 60 ° C. for 2 hours.

Then, a solution containing 1.2 parts of sodium dodecyl sulfate in 64 parts of deionized water was added to the core polymer to give 7.6 parts of 2-hydroxyethyl acrylate, 15 parts of styrene, 10 parts of methyl methacrylate, 30 parts of n-butyl methacrylate, n-butyl acrylate 35.
4 parts, acrylic acid 2 parts, potassium peroxydisulfate 0.
1 part, sodium metasulfite 0.1 part and deionized water 4
The emulsion prepared from 0 part was added dropwise to the core polymer emulsion kept at 60 ° C. over 20 minutes, and polymerization was carried out at the same temperature for 2 hours. The solid content is
It was 30.9% by weight.

(Example 8) (Preparation of emulsion of OH functional group type copolymer) In a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, a gas suction pipe, a dropping funnel and a thermometer, water was added. 102
Part, 1.3 parts of sodium dodecyl sulphate and 0.7 parts of alkyl sulfonate of fatty alcohol were heated to 80 ° C. while flushing with N ₂ .

Next, a solution containing 0.25 part of potassium peroxydisulfate in 12.5 parts of water and 20 parts of styrene, 2
-Ethylhexyl methacrylate 46 parts, butyl acrylate 22 parts, 2-hydroxyethyl methacrylate 1
A reaction flask containing a mixture of 0 parts, 2 parts of acrylic acid, 0.1 part of ethylene glycol dimethacrylate, 20 parts of deionized water, 0.56 parts of alkylphenol polyethylene glycol sulfate and 0.5 parts of triethylamine all at once in a reaction flask. Was added to.

After 5 minutes, a solution containing 0.25 part of potassium peroxydisulfate in 12.5 parts of water was added, and the rest of the monomer mixture was added dropwise over 3.5 hours. Further, in order to complete the polymerization, a solution containing 0.05 part of potassium peroxydisulfate in 3.75 parts of water was added, and the polymerization was further carried out for 2 hours. The solid content of the OH functional group type copolymer emulsion was 40%.

(Examples 9 to 15) 200 parts of each emulsion of Examples 1 to 7 were mixed with 6 parts of dibutyltin dilaurate and 5.5 to 6 parts of N-methylpyrrolidone with vigorous stirring. In Examples 9 and 10, these components were codispersed with 100 parts and 85 parts of the OH functional copolymer emulsion of Example 8 respectively.

The completed transparent emulsion was applied to a clean glass plate using a helical doctor blade (Erichsen, Hemer) to obtain a wet film thickness of 110.
μm. Then, after exposing to air for 5 minutes, baking was performed at 140 ° C. for 25 minutes in a forced air dryer (manufactured by Heraeus). The coating film obtained had good gloss.

The coatings were polished 75 times with a piece of paper impregnated with methyl ethyl ketone. If no evidence of polishing or swelling was found, the solvent resistance was rated as very good. The lacquer was considered good if a slight trace was detected. After separating the membrane from the glass plate,
Soak in acetone for 24 hours, then reweigh at 50 ° C.
It can be dried with and can be accurately determined up to 3 digits after the decimal point 30
Gel contents were determined as a measure of cross-linking by membrane storage using 0-400 mg weights.

The conversion of isocyanate groups was determined by quantitative IR spectroscopy. The measurement results for the emulsion compositions and paints of Examples 9-15 are summarized in the table below.
MEK durability in the table is methyl ethyl ketone (MEK)
The appearance of the film after 75 reciprocating polishing with paper impregnated with was described as 1 for very good and 2 for good. NMP is N
-Methylpyrrolidone.

[0157]

[Table 1]

[0158]

INDUSTRIAL APPLICABILITY The invention can provide an aqueous polymer emulsion excellent in coating film performance and storage stability, a method for producing the same, and a coating composition containing the aqueous polymer emulsion.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location C09D 133/14 PFY 151/00 PGX

Claims (16)

[Claims] 1. A compound represented by the general formula (I): (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄ may be the same or different, 1 to 99% by weight of a unit derived from one or more isocyanate functional type α, β-unsaturated ester represented by (C 1 to C 4 alkyl group in any case), and free radical polymerization An isocyanate-functional copolymer consisting of 99 to 1% by weight of units derived from one or more vinyl monomers, acrylate monomers and / or methacrylate monomers, which are non-reactive with isocyanate groups, An aqueous polymer emulsion, characterized in that the solid content of the polymer emulsion is 5 to 50% by weight. 2. A compound represented by the general formula (II): (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄ may be the same or different, In any case, it is an alkyl group having 1 to 4 carbon atoms, and X is a residue of a protonic acid compound that reacts with an isocyanate group.), An isocyanate group protected by a thermally reversible protecting group 1 to 99% by weight of a unit derived from one or more α, β-unsaturated ester, and one or more vinyl monomer, acrylate monomer and / or which are polymerizable by free radical polymerization and do not react with an isocyanate group Or 99 to 1% by weight of a unit derived from a methacrylate monomer, containing an isocyanate functional type copolymer, wherein the solid content of the polymer emulsion is 5
Aqueous polymer emulsion, characterized in that it is ˜50% by weight. 3. The general formula (I): (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄ may be the same or different, 1 to 50% by weight of a unit derived from one or more isocyanate functional type α, β-unsaturated ester represented by (C 1 to C 4 alkyl group). (A) consisting of 99-50% by weight of units derived from one or more vinyl monomers, acrylate monomers and / or methacrylate monomers, which are polymerized with, and one or more vinyls having active hydrogen atoms in the molecule. 5 to 35% by weight of a unit derived from a monomer, an acrylate monomer and / or a methacrylate monomer, and a monomer which does not react with an isocyanate group and can be polymerized by free radical polymerization, A shell (B) comprising 95 to 65% by weight of a unit derived from the above vinyl monomer, acrylate monomer and / or methacrylate monomer, and the equivalent ratio of active hydrogen atoms to isocyanate groups is 0.5 to 2. A self-crosslinking isocyanate functional core / shell copolymer having a core / shell weight ratio of 20:80 to 70:30 and a solids content of the polymer emulsion of 5 to 50% by weight. Characterized aqueous polymer emulsion. 4. A compound represented by the general formula (II): (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄ may be the same or different, In any case, it is an alkyl group having 1 to 4 carbon atoms, and X is a residue of a protonic acid compound that reacts with an isocyanate group.), An isocyanate group protected by a thermally reversible protecting group 1 to 50% by weight of a unit derived from one or more α, β-unsaturated ester, and one or more vinyl monomer, acrylate monomer and / or which do not react with an isocyanate group and can be polymerized by free radical polymerization. Or 95 to 30% by weight of a unit derived from a methacrylate monomer, and a self-crosslinking isocyanate functional group type copolymer having one or more monomers having an active hydrogen atom. Aneto is equivalent ratio of active hydrogen atoms is from 0.5 to 2 for group, aqueous polymer emulsion, wherein the solids content of the polymer emulsion is from 5 to 50 wt%. 5. A compound represented by the general formula (II): (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄ may be the same or different, In any case, it is an alkyl group having 1 to 4 carbon atoms, and X is a residue of a protonic acid compound that reacts with isocyanate.) And has an isocyanate group protected by a thermally reversible protecting group. 1-50% by weight of units derived from one or more α, β-unsaturated esters, and one or more vinyl monomers, acrylate monomers and / or methacrylates, which do not react with isocyanate groups and are polymerizable by free radical polymerization Units derived from monomers 99
A core (A) consisting of about 50 to 50% by weight, a unit derived from one or more vinyl monomers having an active hydrogen atom in the molecule, an acrylate monomer and / or a methacrylate monomer, from 5 to 35% by weight, and an isocyanate group. A shell (B) consisting of 95-65% by weight of units which are non-reactive, polymerizable by free-radical polymerization, derived from one or more vinyl, acrylate and / or methacrylate monomers,
The equivalent ratio of active hydrogen atoms to isocyanate groups is 0.
5 to 2, and the core / shell weight ratio is 20:80 to 7
An aqueous polymer emulsion containing a self-crosslinking isocyanate functional core / shell copolymer having a solid content of 0:30 and a solid content of 5 to 50% by weight. 6. Free radical polymerization, in which 5 to 35% by weight of a unit derived from one or more vinyl monomers, acrylate monomers and / or methacrylate monomers having active hydrogen atoms in the molecule and free from isocyanate groups. Possible core (A) consisting of 95-65% by weight of units derived from one or more vinyl, acrylate and / or methacrylate monomers
And the general formula (II): (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄ may be the same or different, In any case, it is an alkyl group having 1 to 4 carbon atoms, and X is a residue of a protonic acid compound that reacts with isocyanate.), And has an isocyanate group protected by a thermally reversible protecting group. , 1 to 50% by weight of units derived from one or more different α, β-unsaturated esters and from one or more vinyl, acrylate and / or methacrylate monomers polymerizable by free radical polymerization A shell (B) composed of 99 to 50% by weight of the unit, and the equivalent ratio of active hydrogen atoms to isocyanate groups is 0.
5 to 2, and the core / shell weight ratio is 1:10 to 10 :.
1 and the solid content of the polymer emulsion is 5 to 5
An aqueous polymer emulsion, characterized in that it contains 0% by weight of a self-crosslinking isocyanate-functional core / shell copolymer. 7. The isocyanate functional type α, β-unsaturated ester represented by the general formula (I) is 2-methyl-2-
Isocyanate propyl methacrylate.
Or the aqueous polymer emulsion according to item 3. 8. An α, β-represented by the general formula (II) having an isocyanate group protected by a thermally reversible protecting group.
The unsaturated ester includes 2-methyl-2-isocyanatopropyl methacrylate, alcohol, phenol, ketoxime, ε-caprolactam, dialkyl malonate, alkyl acetoacetate and / or 2,2-dimethyl-1,3-dioxane-4, Aqueous polymer emulsion according to one of claims 2, 4, 5 or 6, characterized in that it is a reaction product with at least one 6-dione. 9. A compound represented by the general formula (I): (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄ may be the same or different, 1 to 99% by weight of one or more isocyanate functional type α, β-unsaturated ester represented by (C 1 to C 4 alkyl group) in any case). A monomer mixture consisting of 99-1% by weight of one or more vinyl monomers, acrylate monomers and / or methacrylate monomers which does not react with isocyanate groups is emulsified in water in the presence of an emulsifier to form a pre-emulsion and then formed. The method for producing an aqueous polymer emulsion according to claim 1, wherein the pre-emulsion thus obtained is polymerized at a temperature of 0 to 100 ° C in the presence of a water-soluble initiator. 10. A compound represented by the general formula (II): (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄ may be the same or different, In any case, it is an alkyl group having 1 to 4 carbon atoms, and X is a residue of a protonic acid compound that reacts with isocyanate.) And has an isocyanate group protected by a thermally reversible protecting group. A monomer comprising 1 to 99% by weight of one or more α, β-unsaturated esters and 99 to 1% by weight of one or more vinyl monomers, acrylate monomers and / or methacrylate monomers, which are polymerizable by free radical polymerization. The mixture is emulsified in water in the presence of an emulsifier to form a pre-emulsion and then the formed pre-emulsion is polymerized at a temperature of 0-100 ° C. in the presence of a water-soluble initiator. Method for producing an aqueous polymer emulsion of claim 2 wherein symptoms. 11. A compound represented by the general formula (I): (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄ may be the same or different, In any case, 1 to 50% by weight of one or more isocyanate functional type α, β-unsaturated ester represented by C1 to C4 alkyl group) is polymerizable by free radical polymerization, 99-5 of one or more vinyl, acrylate and / or methacrylate monomers
0% by weight of the first monomer mixture is emulsified in water in the presence of an emulsifier to form a pre-emulsion, which pre-emulsion is then formed at a temperature of 0-100 ° C.
Completely polymerizing in the presence of a water-soluble initiator, and then 5 to 35% by weight of one or more vinyl monomers, acrylate monomers and / or methacrylate monomers having active hydrogen atoms in the molecule, and an isocyanate group A second monomer mixture, which comprises 95 to 65% by weight of one or more free-radically polymerizable vinyl monomers, acrylate monomers and / or methacrylate monomers, which does not react with The method for producing an aqueous polymer emulsion according to claim 3, wherein the second monomer mixture is completely polymerized. 12. A compound represented by the general formula (II): (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄ may be the same or different, In any case, it is an alkyl group having 1 to 4 carbon atoms, and X is a residue of a protonic acid compound that reacts with isocyanate.) And has an isocyanate group protected by a thermally reversible protecting group. , 1 to 50% by weight of one or more isocyanate functional α, β-unsaturated ester, and one or more vinyl monomer, acrylate monomer and / or methacrylate monomer which does not react with isocyanate and is polymerizable by free radical polymerization 95-30% by weight
And 5 to 35% by weight of one or more monomers having active hydrogen atoms, the monomer mixture is emulsified in water in the presence of an emulsifier to form a preemulsion, which is then heated to a temperature of 0 to 100 ° C. 5. The method for producing an aqueous polymer emulsion according to claim 4, wherein the polymerization is performed in the presence of a water-soluble initiator. 13. A compound represented by the general formula (II): (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄ may be the same or different, In any case, it is an alkyl group having 1 to 4 carbon atoms, and X is a residue of a protonic acid compound that reacts with isocyanate.) And has an isocyanate group protected by a thermally reversible protecting group. 1-50% by weight of one or more α, β-unsaturated esters and 99-50% by weight of one or more vinyl, acrylate and / or methacrylate monomers polymerizable by free radical polymerization. One monomer mixture is emulsified in water in the presence of an emulsifier to form a pre-emulsion, then the formed pre-emulsion is completely heated in the presence of a water-soluble initiator at a temperature of 0-100 ° C. It engaged. Next, one or more vinyl monomers having an active hydrogen atom in the molecule, 5 to 35% by weight of an acrylate monomer and / or a methacrylate monomer, and one or more vinyls which do not react with an isocyanate group and can be polymerized by free radical polymerization. A second monomer mixture, consisting of 95 to 65% by weight of monomers, acrylate monomers and / or methacrylate monomers, is further added together with an initiator and an emulsifier, the second monomer mixture being completely polymerized at a temperature of 0 to 100 ° C. The method for producing an aqueous polymer emulsion according to claim 5, wherein 14. One or more vinyl monomers having an active hydrogen atom in a molecule, 5 to 35% by weight of an acrylate monomer and / or a methacrylate monomer, and one or more polymerizable by free radical polymerization which does not react with an isocyanate group. Vinyl monomer, acrylate monomer and / or
Alternatively, a first monomer mixture consisting of 95 to 65% by weight of a methacrylate monomer is emulsified in water in the presence of an emulsifier to form a pre-emulsion, and the formed pre-emulsion is heated at a temperature of 0 to 100 ° C. Completely polymerize in the presence of the following formula (II) (In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ₂ is an alkylene group having 1 to 18 carbon atoms, R ₃ and R ₄ may be the same or different, In any case, it is an alkyl group having 1 to 4 carbon atoms, and X is a residue of a protonic acid compound that reacts with isocyanate.) And has an isocyanate group protected by a thermally reversible protecting group. Comprising 1 to 50% by weight of one or more α, β-unsaturated esters and 99 to 50% by weight of one or more vinyl, acrylate and / or methacrylate monomers polymerizable by free radical polymerization. The second monomer mixture is further added together with the emulsifier and the initiator, and the second monomer mixture is added at a temperature of 0-
The method for producing an aqueous polymer emulsion according to claim 6, which comprises completely polymerizing at 100 ° C. 15. An aqueous polymer emulsion according to claim 1 or 2, containing a cross-linking agent having at least two or more active hydrogen atoms in the molecule, a cross-linking catalyst, and a solvent,
A crosslinkable composition, which is crosslinked at a temperature of 100 to 180 ° C to give a coating film having solvent resistance and acid resistance. 16. An aqueous polymer emulsion according to any one of claims 1 or 3 to 6, a cross-linking catalyst and a solvent, which are cross-linked at a temperature of 100 to 180 ° C. for solvent resistance and acid resistance. A self-crosslinking composition, which is characterized by providing a coating film of