JPH09241349A - Water-based reactive resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-based reactive resin which has good storage stability, can give wet coating films having excellent driabilify, can give coating films having excellent transparency, gloss, water resistance and solvent resistance, and is desirable as a coating material base, an adhesive or an additive for modifying them. SOLUTION: A resin-forming polymer resin is chemically combined with reactive functional groups and ionic groups which can form a crosslinked structure when reacted with the resin. The formed product should contain 0.1-10wt.% (in terms of silicon), based on the resin, hydrolyzable silyl groups as the reactive functional groups and 0.01-1.1meq per gram of the resin, anionic groups as the ionic groups.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a base (binder) resin, an adhesive, or a modifier resin for a reaction-curable water-based coating.

[0002]

2. Description of the Related Art Polyurethane resin is a resin excellent in adhesion to various base materials and abrasion resistance, and when used as a paint, it gives a thick feeling and a high-grade feeling. It is widely used as a paint for wood, a base for paints for motorcycles and automobiles, an adhesive, a binder, a fiber treatment agent, or a modifier for these, but in recent years, solvent regulations have been adopted in consideration of the impact on the environment. It has been strengthened, and polyurethane paints and adhesives also need to be switched from solvent-based to water-based. However, conventional water-based urethane paints and adhesives are not only inferior in water resistance and solvent resistance as compared with solvent-based ones, but also very important as coating materials such as drying property and appearance (for example, transparency, In addition, it is not satisfactory in terms of water-resistant adhesive performance, which is important in adhesives, etc., and was adopted only in a limited number of applications in the market.

The following methods have been proposed in order to improve the drawbacks of water-based urethane paints, but they still have problems. i) A method of blending a silane coupling agent with an aqueous dispersion of a polyurethane resin (JP-A-4-338140,
JP-A-6-212119). The paints obtained by these methods not only have a problem of pot life, but also have poor appearance and dryness. ii) A method of condensing organosilane in the presence of an aqueous urethane resin (JP-A-6-172711). The paint obtained by this method has solved the problem of pot life, but the hydrolyzable silyl group has completed the reaction in water, and a crosslinked structure has already been formed in the resin particles, and between the resin particles. Since no cross-linking is formed, physical properties comparable to solvent-based paints cannot be obtained. iii) A water-based polyurethane resin composition having a property of introducing an alkoxysilyl group into a cation-modified polyurethane resin and cross-linking during film formation is disclosed (JP-A-1-141911). Aqueous urethane resins of this composition cannot be used in corrosive materials due to their cationic groups.

[0004]

The object of the present invention is to add water-based paint bases or water-based paint bases having improved water resistance, solvent resistance, appearance (particularly transparency and gloss), and also dryability. The present invention also provides an aqueous reactive resin that can be used as an additive for improving its properties, or as an adhesive or a modifier added thereto.

[0005]

The water-based reactive resin which can be used as the water-based paint base of the present invention or an additive to the water-based paint base, or an adhesive or a modifier added thereto, reacts to form a crosslinked structure. Is a water-based resin having a reactive functional group capable of forming a ionic group, wherein (1) a hydrolyzable silyl group is used as the reactive functional group;
0.1 to 10% by weight in the resin as (2) an anion group in the resin as 0.01 to
It contains 1.1 meq / g. The hydrolyzable silyl group reacts with water to become a hydroxysilyl group, which condenses upon drying to form a siloxane bond, and the resin particles crosslink and bond together to rapidly form a film with excellent solvent resistance. .

By adding an anion group to the resin, it becomes possible to make an aqueous resin that disperses or dissolves in water, and by using an anion group, a corrosive material unlike that using a cation The resin can be used for.

The aqueous reactive resin of the present invention is preferably one in which the pH value of the liquid is adjusted to 6-10. When the pH value of the liquid was set to 6 to 10, the reaction of the hydrolyzable silyl group was suppressed, and the aqueous reactive resin having excellent storage stability could be obtained.

The resin used as the water-based reactive resin in the present invention is preferably a polyurethane resin.
Polyurethane resin is a resin that is excellent in flexibility and toughness, and at the same time, a polyisocyanate compound is used in the synthesis stage. Since this isocyanate group (NCO) reacts with various functional groups, the polymer is modified. In addition, it is easy to introduce a special functional group into the molecular chain.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The aqueous solution or dispersion of polyurethane of the present invention comprises an organic diisocyanate, a polyol component and a compound having at least one active hydrogen and a functional group capable of dissociating into an anion in the molecule, in excess of NCO. And a compound having at least one active hydrogen and a hydrolyzable silyl group in the molecule is obtained by reacting a part or all of NCO of the obtained urethane prepolymer containing terminal NCO. Dissolving or dispersing the urethane prepolymer in an aqueous solution containing a basic substance,
It can be obtained by a chain extension reaction with a chain extender consisting of a low molecular weight compound having at least two active hydrogens in the molecule, if necessary. When NCO is dispersed or dissolved in water without using a chain extender, water acts as a chain extender.

Specific examples of the above organic diisocyanates include aliphatic diisocyanates such as ethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate and 1,6-hexamethylene diisocyanate, hydrogenated 4,4'-diphenylmethane diisocyanate. Alicyclic diisocyanates such as 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate and isophorone diisocyanate, 4,4 ′
-Aromatic diisocyanates such as diphenylmethane diisocyanate, xylylene diisocyanate, toluene diisocyanate and naphthalene diisocyanate. Of these, those used for applications in which discoloration over time is to be considered are preferably used alone or as a mixture of aliphatic or alicyclic diisocyanates. The use of methylene diisocyanate or isophorone diisocyanate is particularly preferred.

As the polyol component used in the present invention, those generally used in the production of polyurethane can be used. Such polyols include polyester polyols, polyether polyols, polycarbonate polyols, and the like, and as polyester polyols, succinic acid, glutaric acid, adipic acid, sebacic acid, azelaic acid, maleic acid, fumaric acid, phthalic acid,
One or more dicarboxylic acids such as terephthalic acid, ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,6-hexanediol, neopentyl glycol, 1,8-octanediol, 1 of polyhydric alcohols such as 1,10-decanediol, diethylene glycol and trimethylolpropane
Examples thereof include those obtained by polycondensation of one or more species, and those obtained by ring-opening polymerization of lactones. As the polyether polyol, other than the polyhydric alcohol used in the synthesis of water and the above polyester polyol, bisphenol-
A obtained by subjecting a phenol such as A or a primary or secondary amine to ring-opening addition polymerization of a cyclic ether such as ethylene oxide, propylene oxide, oxetane, or tetrahydrofuran can be used, and polyoxyethylene polyols and polyoxyethylene polyols can be used. Oxypropylene polyol, polyoxytetramethylene polyol, bisphenol A obtained by ring-opening addition polymerization of at least one of propylene oxide or ethylene oxide (in the case of a copolymer,
Either a block copolymer or a random copolymer may be used. ) Can be exemplified. As the polyol, other than this, polybutadiene polyol, polyisoprene polyol, polyolefin polyol, and polyacrylate polyol can be used alone or in combination.

The compound having at least one active hydrogen and a functional group capable of dissociating into anion in the molecule used in the present invention includes dimethylolpropionic acid, dimethylolbutanoic acid, polycaprolactone diol containing a carboxyl group, and sulfuric acid. Examples thereof include salt-containing polyester polyols and di (β-hydroxyethyl) isophthalic acid-5-sulfonic acid.

Of these, the carboxyl group (COOH) -containing compound is preferably used because of problems such as the stability of the final aqueous solution or dispersion and the colorability of the film formed therefrom. Regarding the amount to be used, there is no particular problem as long as these functional groups are incorporated in the resin in an amount of 0.01 meq / g (45 mg in 100 g of resin in the case of COOH) or more. When using a polyol such as a system, in the case of a carboxyl group, 200 mg (0.044 meq /
g) It is preferable that the resin 10 is incorporated in order to stably keep the particle diameter at 80 nm or less even if a highly hydrophobic polyol is used, although it depends on the basic skeleton of the resin.
It is more preferable that 1 g (0.22 meq / g) or more is incorporated with respect to 0 g. When the amount of the functional group is less than 0.01 meq / g in the resin, the particle size becomes large and the dispersion becomes extremely unstable, which is not suitable. Further, even if the amount of functional groups in the resin is 0.01 meq / g or more, if the final dispersion particle size exceeds 80 nm, not only the drying property during film formation becomes poor, but also the glossiness of the film Also, the transparency is lowered, which is not preferable. On the other hand, when the amount of the functional group is remarkably large with respect to the resin, the particle size becomes small and the drying property, glossiness and transparency are improved, but the water resistance and solvent resistance of the film deteriorate. For this reason, the amount of the functional group is within the range of 0.01 meq / g or more in the resin, and the particle size is 80 nm.
Below and so as not to adversely affect the water resistance of the film,
It is important to use the proper amount. When the content of the functional group capable of dissociating into anions is 1.1 meq / g or more, the hydrophilicity of the resin becomes too high, the water resistance of the film is lowered, and the viscosity of the aqueous resin solution (dispersion liquid) is increased. Occurs.

The content of the functional group capable of dissociating into anions is determined in consideration of the balance with the hydrophilicity of the polyol component and the like. For example, when polyoxyethylene glycol is used as the polyol, the content of the functional group should be set low because it itself has hydrophilicity, but when the polyol is hydrophobic, it is set high. There is a need.

Further, as the compound having at least one active hydrogen and a hydrolyzable silyl group in the molecule, the hydrolyzable silyl group is preferably an alkoxysilyl group, and mono-, di-, tri- Any of the alkoxysilyl compounds may be used. Examples of the alkoxysilyl group include a methoxysilyl group and an ethoxysilyl group. Typical compounds include γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropylmethyldiethoxysilane, and N-β (aminoethyl) γ-amino. Examples thereof include propyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane and N-phenyl-γ-aminopropyltrimethoxysilane. In the present invention, these can be used alone or in combination of two or more. The amount of the hydrolyzable silyl group is not particularly limited as long as the amount of the hydrolyzable silyl group is 10 mg (0.01 wt%) or more with respect to 100 g of the resin as Si, but preferably the effect of the cross-linking structure sufficiently appears. Similarly, it is better to use 200 mg (0.2 wt%) or more per 100 g of resin. If the amount is less than 10 mg based on 100 g of the resin, the crosslinking density is low and a sufficient effect cannot be obtained. On the other hand, if the amount used exceeds 10 wt%, the crosslink density in the coating becomes too high and the coating becomes too brittle.

In the present invention, the chain extender comprising a low molecular weight compound having at least two active hydrogens in the molecule is represented by ethylene glycol, propylene glycol, 1,4-butanediol, trimethylolpropane and the like. Low molecular weight glycols, ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, 2,2,4-trimethylhexamethylenediamine, isophoronediamine, dicyclohexylmethane-4,4'-diamine, bisaminodipropylamine, bis Examples include amines such as aminodiethylamine and piperazine, as well as diethanolamine, hydrazine and derivatives thereof. Of these, the chain extension reaction is usually carried out after dispersing the urethane prepolymer in water, so it is more effective to use one having a higher reactivity than water for isocyanates such as amines and hydrazine. A long extension reaction can be carried out, which is preferable.

As the basic compound used in the present invention, for example, triethylamine, triethanolamine, ammonia, sodium hydroxide, potassium hydroxide and the like can be used. At this time, it is important to determine the amount of the basic compound so that the pH of the finally obtained polyurethane aqueous solution or dispersion becomes 6 to 10. p
If the amount of H is 6 or less, the stability of the aqueous polyurethane solution or dispersion may be poor. On the other hand, pH
When it is 10 or more, the stability of the aqueous polyurethane solution or dispersion is good, but not only the polyurethane may be hydrolyzed but also the hydrolyzability incorporated in the side chain and / or the end of the polyurethane. The silyl groups may react with each other in water, which may cause a problem in storage stability. Further, in any of the steps of preparing the polyurethane aqueous solution or dispersion of the present invention, various stabilizers such as an antioxidant and a UV absorber which are added when synthesizing a normal urethane resin, if necessary,
Various surfactants may be added to improve the stability of the aqueous solution or dispersion. Further, when preparing a film from the aqueous polyurethane solution or dispersion of the present invention, if necessary, a crosslinking agent represented by a water-soluble isocyanate, a water-soluble epoxy resin, an aziridine compound, an oxazoline compound and the like may be used in combination. .

The resin of the present invention can be used as an adhesive or a modifier thereof, and in particular, it can be used in combination with another water-based resin adhesive. Examples of such water-based resin adhesives include vinyl acetate-based, acrylic-based, epoxy-based, polyester-based, EVA-based, polyurethane-based, and latex-based adhesives. In particular, many of these water-based resin adhesives are anionic, and the anion-based resin of the present invention has good compatibility and can be used in a wide range of combinations. Further, since the water-based reactive resin of the present invention has a hydrolyzable silyl group, it contributes to the improvement of the adhesiveness of inorganic materials such as glass.

[0019]

(Synthesis example)

(Example 1) 4 equipped with a stirrer, a thermometer, and a nitrogen introducing tube
In a two-necked glass flask, 100 g of isophorone diisocyanate (IPDI), 50 g of Newpol BP-3P (bisphenol A propylene oxide adduct),
Polyoxypropylene glycol 2000 (PPG-2
000) 60 g, and dimethylolpropionic acid (DM
PA) (20 g) was added, MEK (40 g) was added as a solvent, and the mixture was reacted at 80 ° C. for 24 hours using an oil bath. Thereafter, the temperature was lowered to 60 ° C., 10 g of γ-aminopropyltriethoxysilane was added, and the reaction was carried out for 20 minutes. The prepolymer with the remaining NCO groups was dispersed in 550 g of water containing 12 g of triethylamine,
In order to increase the molecular weight, a chain extension reaction was carried out for 3 hours. MEK was recovered from the liquid thus obtained to obtain a translucent resin dispersion liquid containing substantially no organic solvent.

(Example 2) In a 4-neck glass flask equipped with a stirrer, a thermometer, and a nitrogen inlet tube, 100 g of isophorone diisocyanate (IPDI) and Nipporan N- were added.
4073 (Nippon Polyurethane Co., Ltd.) 150 g, DMP
A15g was put, 60g of ethyl acetate was added as a solvent to this, and it was made to react at 80 degreeC for 4 hours using the oil bath. Thereafter, the temperature was lowered to 60 ° C., 20 g of γ-dibutylaminopropyltrimethoxysilane was added, and the reaction was carried out for 20 minutes. The obtained prepolymer was dispersed in 500 g of water containing 9 g of triethylamine, and chain length extension reaction was carried out at 50 ° C. for 3 hours to obtain a high molecular weight. MEK was recovered from the liquid thus obtained to obtain a translucent resin dispersion liquid containing substantially no organic solvent.

Comparative Example 1 A light white resin dispersion was obtained in the same manner as in Example 2 except that γ-dibutylaminopropyltrimethoxysilane was not reacted. This comparative example corresponds to a resin which does not have an alkoxysilyl group in the molecular chain and has no reaction curing ability.

(Comparative Example 2) A thin white resin dispersion was prepared in the same manner as in Example 2 except that γ-dibutylaminopropyltrimethoxysilane was not reacted, and γ-dibutylaminopropyltrimethoxy was added to the dispersion. Methoxysilane was added. This comparative example corresponds to the case where the alkoxysilyl group does not bond to the resin constituent molecule and exists separately in the dispersion liquid.

Comparative Example 3 A light white resin dispersion was obtained in the same manner as in Example 1 except that γ-aminopropyltriethoxysilane was not reacted. (Comparative Example 4) A light white resin dispersion was prepared in the same manner as in Example 1 except that γ-aminopropyltriethoxysilane was not reacted, and γ-aminopropyltriethoxysilane was added to the dispersion. .

[Performance Evaluation] (Evaluation of Storage Stability) The resin dispersion liquid was subjected to 1
It was left for a month and the state of the liquid was observed. The evaluation was shown as ⊚: no change, x: viscosity increase, gelation. (Creation of coating film, performance evaluation) A resin dispersion liquid was applied onto a glass plate using an applicator to prepare. Regarding the drying property, the resin dispersion liquid film after coating was allowed to stand at 50 ° C. for 20 minutes, and the dried state of the film was observed. The evaluation results were displayed as follows. ◯: It is dry and has no stickiness. X: Not dried Regarding water resistance, toluene resistance, ethanol resistance, transparency, and gloss, the resin dispersion liquid film after coating with an applicator was left at room temperature for 5 days to form a film, and tests were conducted. The method of each performance evaluation and the display of the evaluation results are as follows. (Water resistance, toluene resistance, ethanol resistance)
Absorbent cotton moistened with water, toluene, or ethanol was woken up, and the state of each film after 24 hours was visually observed. ⊚: No change ◯: Almost no change Δ: Whitening and swelling are partially observed ×: Whole whitening and swelling (transparency) The transparency of the obtained film was visually observed. ⊚: Completely transparent ◯: Almost transparent Δ: Slightly opaque ×: Completely opaque (gloss) The gloss of the obtained film was visually observed. ◎: Very glossy ○: Glossy △: Not very glossy ×: No gloss at all

The above results are summarized in Table 1. From these results, the particle size of the resin in the dispersion is about 50 nm, the drying property and storage stability are excellent, and the transparency and gloss of the film obtained by drying are good, as well as the water resistance and solvent resistance. It turns out that it is also excellent.

[0026]

In the water-based paint base of the present invention, p
By controlling H to be 6 to 10, it is possible to stabilize the side chain and / or the terminally hydrolyzable silyl groups of the resin in water without condensing each other, and at the time of film formation, As the condensation reaction proceeds, a dense and highly crosslinked film is formed. Furthermore, the polyurethane aqueous solution or dispersion of the present invention has a small particle size of 80 nm or less, so that not only a uniform film is formed, but the condensation reaction proceeds only during film formation, so that the condensation reaction is performed only inside the particles. Since the condensation also occurs between the particles, the interface between the particles, which has been a weak point in the conventional water system, does not exist, and the water resistance and solvent resistance of the film are comparable to those of the conventional solvent system.

It can also be used as an adhesive having excellent water-resistant adhesive strength.

[0028]

[Table 1]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C09J 175/04 JFA C09J 175/04 JFA 201/10 JAQ 201/10 JAQ

Claims (3)

[Claims] 1. A water-based resin having a reactive functional group capable of reacting to form a crosslinked structure and an ionic group, comprising: (1) a hydrolyzable silyl group as a reactive functional group, Si
0.1 to 10% by weight in the resin as (2) an anion group in the resin as 0.01 to
An aqueous reactive resin containing 1.1 meq / g. 2. The aqueous reactive resin according to claim 1, wherein the pH value of the liquid is adjusted to 6 to 10. 3. The resin is a polyurethane resin.
Alternatively, the water-based reactive resin according to item 2.