JPH0481447A - Aqueous emulsion composition of crosslinkable polyurethane acrylic resin - Google Patents

Abstract

PURPOSE:To obtain the subject composition capable of forming a coating film having excellent alcohol resistance and high water resistance and hardness and suitable for the coating of a wood work by compounding a self-emulsifiable polyurethane with an aqueous emulsion of a cold-crosslinking acrylic resin. CONSTITUTION:The objective composition is produced by compounding (A) a self-emulsifiable polyurethane with (B) an aqueous emulsion of a cold- crosslinking acrylic resin having the lowest film-forming temperature of 0-70 deg.C and produced by compounding a polyhydrazine compound having >=2 hydrazine groups to an aqueous emulsion of a copolymer produced by the emulsion polymerization of 1-20wt.% of an ethylenic unsaturated monomer containing carbonyl group or aldehyde group, 25-75wt.% of a methacrylic acid l-4C alkyl ester and 10-55wt.% of an acrylic acid l-8C alkyl ester (the sum of the monomers is 100wt.%). The weight ratio of (A/B) is 1/(l.8-9) in terms of solid component.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The crosslinkable polyurethane/acrylic resin aqueous emulsion composition of the present invention is useful as a coating material for base materials such as wood, metal, leather, and paper.

(Prior art) Water-based polyurethane paints have been used in place of solvent-based polyurethane paints since the 1960s for environmental hygiene reasons.This water-based polyurethane paint can be coated either transparently or colored, and has excellent gloss and weather resistance. This water-based polyurethane paint is mainly used as a coating for wood products, paper, and steel.

However, improvements in water resistance and the balance between hardness and elasticity have been desired. As a method to improve this point, a method has been proposed in which an aqueous acrylic acid alkyl ester/styrene copolymer aqueous emulsion or an acrylic acid alkyl ester resin aqueous emulsion is blended with water-based polyurethane [Technical data from Gunze Sangyo Co., Ltd.]
Sheet “Polyurethane for sunker coating”.

This blending method uses the same data sheet and JP-A-59
As shown in Comparative Examples 1 and 2 of JP-A-138211, it has been pointed out that there is a drawback that the film becomes cloudy.

As a means for preventing fogging of such a film and improving the hardness of the film, JP-A-59-138211 discloses that a urethane prepolymer obtained from a diisocyanate and a polyol with a molecular weight of 200 to 4000 is used as a urethane chain with a molecular weight of 300 or less. 2 to 40 parts by weight of polyurethane crosslinked with an extender is mixed with 100 parts by weight of an ethylenically unsaturated monomer such as methyl methacrylate, butyl acrylate, or styrene, and this polymerizable solution is dispersed in water. A method for producing an aqueous polyurethane/acrylic resin emulsion by emulsion polymerization has been proposed.

According to this method, an aqueous emulsion coating material is obtained which provides a transparent film with excellent water resistance and hardness. but,
Alcohol resistance is insufficient.

[Problem to be solved by the invention]

Alcohol such as whiskey, sake, wine, and beer are drunk at banquets. If these spill on the desk,
If alcohol spills in the hallway, alcohol stains may remain on desks and hallways even after wiping it up with a cloth. An object of the present invention is to provide a polyurethane/acrylic resin aqueous emulsion composition that provides a film having good alcohol resistance as well as water resistance and hardness.

[Specific means to solve the problem]

A film that is free from alcohol stains is provided by a blend of self-emulsifying polyurethane and an aqueous emulsion of an acrylic resin that crosslinks at room temperature.

That is, in the present invention, the room temperature crosslinkable acrylic resin aqueous emulsion (B) is added to the self-emulsifying polyurethane (A) in a solid content weight ratio (A/B) of 1/1.8 to 1/9. The present invention provides a crosslinkable polyurethane/acrylic resin aqueous emulsion composition.

(Polyurethane resin) As a polyurethane resin, Journal ofCoa
tings Tecbr+ology) vol.
58. No. 738゜July 1986 49-51
Page and JP-A-59138211, Industrial Painting Nα
90. The molecular weight is 200 as described on pages 38-39.
~4.000 polyols with isocyanate groups (-NG
Polyurethane or urethane prepolymer (OCN-R- NH-Co--QC-NH-R-NCO
) and HOCHHzCHz N CHz・CH20HNH-
R-NHC-←0CHzCHz)X A polyurethane having a nonionic group represented by the following formula and having a high molecular weight with a chain extender having a polyether group represented by R can be used.

Polyisocyanates used as raw materials for polyurethane include aromatic, aliphatic, and alicyclic diisocyanates, such as 1
, 5-naphthene diisocyanate, 4.4'-diphenylmethane diisocyanate, 4.4 diphenyldimethylmethane diisocyanate, di- and tetraalkyldiphenylmethane diisocyanate, 4,4°-dihenzyl diisocyanate, 1.3-phenylene diisocyanate, 1,4 - phenylene diisocyanate, toluylene diisocyanate, chlorinated diisocyanates, brominated diisocyanates, 1,4-butylene diisocyanate, 16-hexane diisocyanate and xylylene diisocyanate, to name a few.

Further, as polyols, any of those used in general urethane products such as polyethers, polyesters, polyesteramides, polythioethers, polybutadiene glycols, etc. can be used. Polyethers are usually produced by ring-opening addition polymerization of ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, etc. using compounds with active hydrogen such as water, ethylene glycol, propylene glycol, gutsselin, and bisphenol A as initiator raw materials. It will be done.

Examples of polyesters include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, bentanediol, hexanediol, octanediol, 2-ethyl 1,3-hexanediol, bisphenol A, It is obtained by condensation of saturated and unsaturated low molecular weight glycols such as diethylene glycol and dipropylene glycol with tribasic acids.

Other polythioethers and polyacetals can also be used. To obtain these urethane polymers, the CPR of polyols is usually lowered to L (for CPR, JIS K
1557), synthesized at a reaction temperature of about 30 to 150°C, the molar ratio of polyisocyanate/polyol during synthesis is 0.5 to 2.5 moles of isocyanate group per hydroxyl group of polyols. be done.

As a chain extender, N-methyljetanolamine, N-
Ethylgetanolamine, N-oleylgetanolamine, dimethylolpropionic acid, ethylene glycol, diethylene glycol, triethylene glycol,
Propylene glycol, dipropylene glycol, 1,
3-butylene glycol, tetramethylene glycol,
hexamethylene glycol, 1,4-butanediol,
Neopentyl glycol, also diaminoethane, 1.6-
Diamithexane, piperazine, 2,5-dimethylpiperazine, 4,4'-diaminodicyclohexylmethane,
1.2-propylene diamine, hydrazine, etc.
Used alone or in combination.

(Room-temperature crosslinkable acrylic resin aqueous emulsion) A room-temperature crosslinkable acrylic resin aqueous emulsion is an acrylic copolymer resin aqueous emulsion having a carbonyl group (>C=O) or an aldehyde group (-CHO), and a polyhydrazine compound. The manufacturing method is disclosed in Japanese Patent Application Laid-open No. 5
No. 4-110248, No. 62-72742, Special Publication No. 6
No. 3-51180, Special Publication No. 1-13501, No. 1-4
It is described in Publication No. 5497 and the like.

Among these, room temperature crosslinkable acrylic resin aqueous emulsion, a) ethylenically unsaturated monomer containing carbonyl group or aldehyde group 1 to 20% by weight b) methacrylic acid alkyl ester (alkyl group has 1 to 4 carbon atoms) 2
5-75% by weightC) Acrylic acid alkyl ester (alkyl group has 1-8 carbon atoms) 10-55% by weightd
) Other ethylenically unsaturated monomers 0 to 40% by weight The sum of components (a), b), C) and d) is 100% by weight
It is. ] Hydrazine M (-N)l-N)I is added to the copolymer aqueous emulsion obtained by emulsion polymerization of the above components (a) to (d).
A film containing a polyhydrazine compound having two or more of 2) and having a minimum film forming temperature of 0 to 70°C is preferable in terms of blocking resistance and alcohol resistance.

Component a) is a vinyl monomer used to introduce a crosslinkable carbonyl group or aldehyde group into the copolymer obtained by emulsion polymerization, and has at least one aldehyde group or carbonyl group in the molecule. It is a monomer having a polymerizable double bond, ie a polymerizable monoolefinic aldo or keto compound. As a carbonyl group, an ester bond (-C-O-) and a carboxyl group O are not included in the monomer. The monomers include, for example, acrolein, diacetone acrylamide, formylstyrene, vinyl alkyl ketones having 4 to 7 carbon atoms (e.g. vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone), general formulas (wherein R1 is H or C)1. ．． 172 is H or 1~
An alkyl group having 3 carbon atoms, R3 is an alkyl group having 1 to 3 carbon atoms, and R4 is an alkyl group having 1 to 4 carbon atoms. ) Acrylic (or methacrylic) oxyalkylpropanal, acetonitrile acrylate, diacetone acrylate, diacetone methacrylate, 2-hydroxypropyl acrylate-acetylacetate,
Examples include butanediol-14 acrylate-acetylacetate. Particularly preferred are diacetone acrylamide, acrone and vinyl methyl ketone. Two or more types of these monomers may be contained in the copolymer.

Component b) methacrylic acid alkyl ester imparts hardness and toughness to the film, and includes methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, normapropyl methacrylate, t-butyl methacrylate, and n-methacrylate. Butyl is used.

Component C) acrylic acid alkyl ester, together with polyurethane resin, imparts flexibility and elasticity to the film, and includes methyl acrylate, ethyl acrylate, isopropyl acrylate, n-propyl acrylate, n-butyl acrylate, Monobutyl acrylate, 2-ethylhexyl acrylate, etc. are used.

d) Components include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid, and maleic acid; acrylonitrile, acrylamide, methacrylamide,
Examples include hexyl methacrylate, styrene, vinyl acetate, α-methylstyrene, ethylene, vinyl chloride, etc., and these are used to adjust the minimum film forming temperature of the resulting copolymer aqueous emulsion and to introduce functional groups into the copolymer. 0 to 40
Used in proportions by weight.

If the amount of the vinyl monomer having a carbonyl group or aldehyde group used as component a) is less than 1% by weight in the monomer mixture, the crosslinking density of the film will be low and the alcohol resistance will not be improved. On the other hand, if it exceeds 20% by weight, the coating will become too hard and its ability to follow the shrinkage of the substrate will deteriorate.

If the amount of the methacrylic acid alkyl ester used as component (b) is less than 25% by weight in the vinyl monomer mixture, no improvement in the hardness of the film can be expected and the film is easily damaged.

On the other hand, if it exceeds 75% by weight, the film tends to be brittle.

C) The amount of acrylic acid alkyl ester used as component is 10
If the amount is less than % by weight, the elasticity of the film will be impaired.

Vinyl acetate, butadiene, etc. may be used instead to impart elasticity to the film, but since the weather resistance, gloss, and transparency of the film will decrease, at least 10% by weight or more of acrylic acid alkyl ester in the monomer mixture should be used. . Conversely, 55% by weight
Exceeding this is not preferable because the hardness of the film decreases too much.

The crosslinking agent to be added to the emulsion of the copolymer having carbonyl groups and/or aldehyde groups in the molecular chain obtained by emulsion polymerization of components a) to d) includes at least two hydrazine groups ( -NH-Nl2), such as the following dicarboxylic acid dihydrazide containing 2 to 10 carbon atoms, particularly 4 to 6 carbon atoms.

Oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide and/or itaconic acid dihydrazide, aqueous aliphatic acids having 2 to 4 carbon atoms dihydrazines such as ethylene-1,2-dihydrazine, propylene-1,3-dihydrazine and butylene-1,3-dihydrazine
1,4-dihydrazine. and the general formula [wherein, and B is acrylamide, methacrylamide, acrylic ester, methacrylic ester, or other monomer copolymerizable with maleic anhydride. Also, 12. m and n represent numbers that satisfy the following conditions: 22 mol%<f<100 mol%, 0 mol%<m+n<98 mol%, 12, +m'-, n=100 mol%. ] A water-soluble acid hydrazide polymer represented by the following can be used.

The crosslinking agent is used in a proportion such that the -NH-NHz group is 0.01 to 2.5 equivalents per mole of the carbonyl group and/or aldehyde group of component a in the vinyl monomer mixture constituting the copolymer. It is blended.

(Blending) The blending ratio of polyurethane (A) and room-temperature crosslinkable acrylic resin aqueous emulsion (B) is based on the solid content weight ratio of the resin (
A/B) is 1/1.8 to 1/9. 1/1.8
If it is less than that, the effect of improving alcohol resistance will not be sufficient.

On the other hand, if it exceeds 1/9, the film will not have sufficient ability to follow the shrinkage (heat shrinkage, drying shrinkage) of the base, and will not have sufficient gloss, which is a characteristic of urethane emulsions. Also, the hardness of the film after initial coating and drying for -10 days is not sufficient.

(Room-temperature crosslinkable polyurethane/acrylic resin aqueous emulsion composition) The room-temperature crosslinkable resin aqueous emulsion composition of the present invention may optionally contain a film-forming agent, an antifoaming agent, a thickener, a dye, a pigment, a filler, and a freezing agent. It is used as a clear coat agent, top coat agent, paint, undercoat agent, and impregnating agent for cloth and paper.

[Examples, etc.]

Polyether BPX-3 Example 1 Inside the flask under a nitrogen seal,
3104gr, then xylylene diisocyanate 6
3 gr was charged and the temperature was raised to 75-80°C. The reaction was slightly exothermic. After confirming the completion of the reaction while measuring the NC0% of the reaction product, dimethylolpropionic acid 7.
4 gr and 10.9 gr of 1,4-butanediol were added, and the reaction temperature was maintained at 75° to 80° C. as in the previous step.

When the viscosity gradually increased and it became difficult to stir, 80g of dioxane was added, and the reaction was further continued.At the point when the viscosity increased, it was confirmed by infrared absorption spectrum that there was almost no remaining NGO group, and then 104g of ammonia water was added. The internal temperature was lowered to 35° C. over 30 minutes, and 160 g of pure water was added to obtain polyurethane with a solid content concentration of 35% by weight.

Example 2 SANNCOR Industries, Inc. (USA)
TNDUSTRIES INC.)'s water-soluble polyurethane "Thank You Waterborne #898'" (
(trade name; solid content concentration 35% by weight) was used.

Acrylic 1, Emulsion Example 1 After adding 68 parts of methyl methacrylate, 26 parts of n-butyl acrylate, 1 part of acrylic acid and 5 parts of diacetone acrylamide into a flask, 4 parts of polyethylene oxide nonylphenyl ether sulfate sodium salt were added. A solution obtained by dissolving 1 part in 20 parts of water was further added thereto, and the mixture was stirred and mixed to obtain an emulsion.

The temperature of this emulsion was raised to 80°C over 1 hour, and at the same temperature, 10 parts of a 2% aqueous solution of potassium persulfate was added to the flask over 2.5 hours, and the emulsion was further kept at the same temperature for 1 hour to induce emulsion polymerization. finished. An aqueous acrylic copolymer emulsion with a low film-forming temperature of 40°C was obtained.

After cooling this to 20℃, 2
12.5 gr of 0% aqueous solution was added to obtain a cold crosslinkable acrylic copolymer aqueous emulsion having a film forming temperature (MFT) of about 40° C., pH 7.9, and solid content of about 40.8%.

Examples 2 to 6 Emulsion polymerization was carried out in the same manner except that the vinyl monomer mixture shown in Table 1 was used to obtain an aqueous acrylic resin emulsion. In some cases, a crosslinking agent was added to create an aqueous resin emulsion that is crosslinkable at room temperature.

Example 1 30 parts of the polyurethane obtained in Example 1 and 70 parts of the room temperature crosslinkable acrylic copolymer aqueous emulsion obtained in Example 1 were mixed and stirred to form a room temperature crosslinkable polyurethane/acrylic resin composition. Obtained.

Comparative Example 1 Polyurethane and
An acrylic resin aqueous emulsion composition was obtained.

Examples 2-9. Comparative Examples 2-3 30 parts of SunCure Waterborn #89B (trade name) as a self-emulsifying polyurethane was placed in a flask, and then the acrylic resin aqueous emulsion obtained in Production Examples 1-6 was added in the amount shown in Table 2. In addition, the mixture was stirred and mixed to obtain a polyurethane/acrylic resin aqueous emulsion composition coating material.

Comparative Example 4 The room temperature crosslinkable acrylic resin aqueous emulsion obtained in Production Example 1 was used as a coating material.

Comparative Example 5 Sancor Industries, Inc. (SANNCORT)
A water-soluble polyurethane "SunCure Waterborn #898" (trade name) manufactured by NDUSTRIES INC. was used as the coating material.

[Evaluation Method] The coating materials obtained in Examples 1 to 9 and Comparative Examples 1 to 6 were evaluated by the following method. The results are shown in Table 2.

It was applied on alcohol Chinese plywood at 20°C to obtain a 100 micron thick film, and after drying for one day, the gloss and smoothness of the film was visually inspected, and the best one was ranked 1.2. It was set as .3.

In addition, 3 drops of a 50% ethanol aqueous solution was dropped onto the coating of this coated Chinese plywood using a dropper, and after 30 minutes, the alcohol solution was wiped off with a cloth to determine the degree of traces of alcohol from 0 (no) to slight traces. (Δ), X (diameter of 3 to 5 anus) was evaluated.

In addition, for another coated Chinese plywood, make squares (100 squares) on the film with a knife, apply adhesive tape "Cello Tape" (trade name) from Nichihan C Co., Ltd. on these squares, and after pressing the tape, A substrate peeling test was conducted in which the tape was peeled off and the number of squares in the film remaining on the Chinese plywood was determined.

A coating material was applied onto a glass plate to form a film of 100 microns, and the coating material was dried at 20° C. for one day to obtain a coated glass plate.

The transparency of this film (〇 - transparent, × - cloudy) was visually examined.

The pencil hardness of this coated glass plate was examined.

Furthermore, after immersing another coated glass plate in water for one day,
Wipe off the water with a cloth and check whether the film has whitened (○- none, ×-
There are only a few).

Furthermore, a bleached cloth was laid on the film of another coated glass plate, a 500g load was placed on it, and it was left in a constant temperature room at 40℃ for one day. When the load and the bleached cloth were removed, there were no traces of the exposed cloth on the film. Good anti-blocking properties (○
), and those that remained were classified as having poor anti-blocking properties (X).

A coating material was applied onto the four-track inspection board so as to obtain a film with a thickness of 100 microns, and the coating material was dried at 20° C. for 2 days to form a film.

This coated waste board was heated at -20°C for 1 hour, then at +50°C.
The act of storing for 1 hour was repeated 10 times, and it was investigated whether cracks or lifting of the film occurred (〇-No,
×-Yes).

Claims (1)

[Scope of Claims] 1) Self-emulsifying polyurethane (A) is mixed with room-temperature crosslinkable acrylic resin aqueous emulsion (B) at a solid content weight ratio (A).
/B) in a ratio of 1/1.8 to 1/9. 2) The room temperature crosslinkable acrylic resin aqueous emulsion contains: a) 1 to 20% by weight of an ethylenically unsaturated monomer containing a carbonyl group or an aldehyde group; b) an alkyl methacrylate ester (the number of carbon atoms in the alkyl group is 1 to 4)25 ~75% by weight c) Acrylic acid alkyl ester (alkyl group has 1 to 8 carbon atoms) 10 to 55% by weight d) Other ethylenically unsaturated monomers 0 to 40% by weight [However, a), b) , the sum of components c) and d) is 100
Weight%. ] A hydrazine group (-NH・NH_2) is added to the copolymer aqueous emulsion obtained by emulsion polymerization of the above components (a) to (d).
2. The composition according to claim 1, wherein the composition contains a polyhydrazine compound having two or more of which has a minimum film-forming temperature of 0 to 70[deg.]C.