JPH01301761A - Aqueous coating agent composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition, consisting of a specific aqueous polyurethane resin and aqueous dispersion of an acrylic copolymer and having elasticity and abrasion resistance of the urethane resin functionally combined with weather resistance and toughness of the acrylic resin. CONSTITUTION:The objective composition, consisting of (A) an aqueous polyurethane resin prepared by reacting diisocyanates with glycols containing carboxylic acid group-containing glycols, neutralizing the resultant urethane prepolymr and extending the chain with a hydrazine derivative and (B) an aqueous dispersion of an acrylic copolymer containing a carbonyl group- or amide group- containing monomer in an amount of >=0.5pt.wt. based on 100pts.wt. total polymerizable monomers in constituent monomers of the acrylic copolymer and using the components (A) and (B) at 100/5-5/100 weight ratio of the components (A)/(B).

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to aqueous coating compositions. For more details,
This relates to an aqueous coating composition consisting of an aqueous polyurethane resin and an aqueous acrylic copolymer dispersion, which functionally combines the elasticity and abrasion resistance of the urethane resin with the weather resistance and toughness of the acrylic resin. It is a composition that can be widely used as a coating for cement, concrete, metal, paper, leather, wood, etc.

[Prior art and its problems] Aqueous acrylic copolymer dispersions have traditionally been used as coatings for interior and exterior buildings, leather, metals, wooden floors, etc. due to their excellent weather resistance and toughness. It has been used in a wide variety of applications such as impregnating fibers or as a binder, adhesives, and glues.

However, in recent years, quality has improved, coating base materials have changed,
As they are used in new applications, the performance requirements for coating compositions are becoming more sophisticated, and in addition to conventional weather resistance, the number of applications that require film elasticity and abrasion resistance comparable to that of urethane resins is increasing. It's coming.

In order to obtain such physical properties, as a method for improving the aqueous acrylic copolymer dispersion, various acrylic functional groups are added.
Since it is difficult to obtain an acrylic resin with elasticity comparable to that of urethane resin, it has been desired to investigate the problem.

On the other hand, water-based polyurethane resin as a water-based coating composition is developed by focusing on the elasticity and abrasion resistance that are the characteristics of this resin.
Traditionally, it has been used to coat textiles, paper, leather, plastics, wooden floors, etc., or when used dry, it has water resistance, alkali resistance, which is thought to be due to the water-soluble substances used to make it water-soluble. Due to poor weather resistance and, in the case of urethane dispersions, poor film-forming properties between particles, which is thought to be caused by the strength of the cohesive force within the particles, their use was mostly limited to indoor environments. In addition, in practice, the resin is often used in combination with a crosslinking agent and subjected to high-temperature heating and drying, and only under these conditions can the elasticity unique to urethane resins be obtained.

In order to develop an aqueous coating composition that has the weather resistance and toughness of an acrylic resin in addition to the elasticity and abrasion resistance of a urethane resin, we developed an aqueous dispersion of an aqueous polyurethane resin and an acrylic copolymer. Mixing etc. of
Mere mixing will only increase the disadvantages of each resin.
In other words, in many cases, only properties that combine the weak elasticity of aqueous acrylic copolymer dispersions and the poor weather resistance of water-based polyurethane resins can be obtained, and there is a strong desire to develop a resin that combines the characteristics of both. It had been.

Means for Solving Problem 1] The present inventors have conducted research in order to develop an aqueous coating composition that has both the elasticity and abrasion resistance of urethane resins, as well as the weather resistance and toughness of acrylic resins. As a result of repeated research, it was discovered that the above problems could be solved by not simply mixing the aqueous polyurethane resin and the aqueous acrylic copolymer dispersion, but by functionally linking the two, and the present invention was developed. I have finally completed the .

That is, the present invention provides an aqueous urethane prepolymer obtained by neutralizing a urethane prepolymer obtained by reacting a cyisocyanate 1- with a glycol containing a carboxylic acid group-containing glycol, and extending the chain with a hydrazine derivative. Polyurethane resin (A) and a carbonyl group-containing monomer or an amide group-containing monomer in the constituent monomers of the acrylic copolymer are at least 0.5 parts by weight based on 100 parts by weight of the total polymerizable monomers. acrylic copolymer aqueous dispersion (B), the solid content weight ratio (A)/(B) -100
15 to 5/100.

The present invention will be described in detail below.

The aqueous polyurethane resin used in the present invention is produced, for example, as follows. That is, first, a diisocyanate, a glycol, and a glycol having a carboxylic acid group are subjected to a urethanization reaction to form a urethane prepolymer (
qru.

The diisocyanates used at this time include aliphatic, alicyclic or aromatic diisocyanates, such as 2,4-tolylene diisocyanate, 2,4-tolylene diisocyanate,
．． 6-tolylene diisocyanate, 4.4°-diphenylmethane diisocyanate, m-)technyl diisocyanate, xylylene diisocyanate, tetramethylene diisocyanate, lysine diisocyanate, 1,4-
Cyclohexylene diisocyanate. 4,4°-dicyclohexylmethane diisocyanate, 3.3°-dimethyl-4,4′-diphenylene diisocyanate, 3,3
"-dimethoxy-4,4'-biphenylene diisocyanate, 3,3'-dichloro-4,4"-biphenylene diisocyanate, 1,5-naphthalene diisocyanate-1
-, 1.5-te1-lahydronaphthalene diisocyanate, isophorone diisocyanate i, etc.

Glycols used in preparing urethane prepolymers include low molecular weight glycols, high molecular weight glycols,
Polyester polyols, polycarbonate polyols, etc. may be used alone, or, as is well known in urethane technology, low molecular weight glycols may be used in combination with polyester polyols and high molecular weight glycols.

Examples of low molecular weight glycols include ethylene glycol,
Diethylene glycol, triethylene glycol, 1,
2-propylene glycol, 1,3-butylene gelicol, 1-ramethylene glycol, hex]namedylene glycol, dicamedylene glycol, octanediol, tricyclodecane dimedylol, hydrogenated bisphenol△, Examples include cyclohexane dimetatool, and two or more of these may be mixed.

Examples of high molecular weight glycols include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

The polyester polyols may be those obtained by reacting a glycol component and a dicarboxylic acid component, and can be easily produced by a known method. That is, the reaction is not limited to esterification reaction, but may also be transesterification reaction. That is, the bo-1-noester botuol of the present invention can also be produced by transesterification using lower alkyl esters of glycol dicarboxylic acids.

As glycols having a carboxylic acid group, 2.2-
Dimethylolpropionic acid, 2,2-dimethylolacetic acid, ? , 2-dimethylolvaleric acid and the like.

The reaction involves dioxane, acetone, methyl ethyl ketone,
It is preferable to carry out the reaction in an organic solvent that is inert to isocyanate groups and has a high affinity for water, such as N-methylpyrrolidone or tetrahydrofuran.

The prepolymer is then neutralized and chain extended, and distilled water is added to obtain a water-based polyurethane resin.

The organic solvent used in the reaction may be removed by a known method if necessary.

As a neutralizing agent, tolylene diamine, triethylamine, 1-n-propylamine, 1-1 butylamine,
Amines such as triethanolamine; examples include sodium hydroxide, potassium hydroxide, ammonia, and the like.

In the present invention, it is necessary to use a hydrazine derivative as a chain extender. Hydrazine derivatives include hydrazine, ethylene-1,2-dihydrazine, propylene-
Examples include 1,3-dihydrazine and butylene-1,4-dihydrazine.

Chain extenders for urethane prepolymers generally include polyols such as ethylene glycol and propylene glycol; ethylene diamine, propylene diamine, hexamethylene diamine, tolylene diamine, xylylene diamine, diphenyl diamine, diaminodiphenylmethane, diamincyclohexylmethane, Aliphatic, cycloaliphatic and aromatic diamines such as piperazine, 2-methylpiperazine, isophorone diamine are well known or in the present invention such compounds are used for functional combination with aqueous acrylic copolymer dispersions. No effect has been found on ties.

That is, it is necessary that the polymer molecule end of the aqueous polyurethane resin obtained when chain elongation of the urethane prepolymer is carried out has a chemical structure of -NHN H2, and this chemical structure must be maintained. Only then can the aqueous urethane resin and the aqueous acrylic copolymer dispersion be functionally linked.

In the present invention, the acid value in the aqueous polyurethane resin is preferably 10 to 200 per resin solid content. If the acid value is less than 10, aggregates are likely to form when the urethane prepolymer reacted in an organic solvent is made aqueous using a neutralizing agent, a chain extender, and distilled water, and the storage stability of the resulting aqueous polyurethane resin is reduced. Sometimes the sex is also bad. On the other hand, if the acid value exceeds 200, desirable physical properties such as durability and water resistance may not be obtained when the aqueous acrylic copolymer dispersion is functionally combined.

The acrylic monomers used to obtain the aqueous acrylic copolymer dispersion of the present invention include carbonyl group-containing monomers or amide group-containing monomers in a total amount of 10% of the total polymerizable monomer.
The requirement is to contain at least 0.5 parts by weight compared to 0 parts by weight, but conventionally known surfactants, protective colloids, and polymerization initiators used in emulsion polymerization are used. be able to.

The carbonyl group-containing monomer is a monomer containing an aldo group or a keto group, and has a nistyl bond (-C
-O-) or a compound having only a carboxyl group (-C-DH) is not included in this monomer.

Examples of carbonyl group-containing monomers applicable to the present invention include acrolein, diacetate acrylamide, vinyl ethyl ketone, vinyl ethyl ketone, vinyl butyl ketone, diacetone acrylate, acetonitrile acrylate-1, etc. .

Examples of the amide group-containing monomer include monoolefinically unsaturated carboxylic acid amides, N-alkyl derivatives of monoolefinically unsaturated carboxylic acid amides, and N-alkylol derivatives of monoolefinically unsaturated carboxylic acid amides. . Examples of suitable monomers include acrylic acid,
Amides of methacrylic acid, itaconic acid or maleic acid; N-methylacrylamide, N-isobutylacrylamide, N-methylmethacrylamide, N-medyrollacrylamide, N-methylolmethacrylamide, N
Examples thereof include hexymethylacrylamide, n-butoxymethylacrylamide, and N-isopropoxymethacrylamide.

These carbonyl group-containing monomers or amide group-containing monomers may be used alone or in combination, but
At least 0.5 parts per 100 parts of total polymerizable monomers
Parts by weight are necessary, and a particularly preferable range is 1.0 to 10
．． Required at 0 parts by weight. If it is less than 0.5 parts by weight, the functional effects of the aqueous polyurethane resin and the aqueous 1-nor copolymer dispersion will not be observed, and the weather resistance, water resistance, alkali resistance, elasticity, abrasion resistance, etc. It is difficult to obtain significant improvements in physical properties.

Acrylic monomers other than those mentioned above that can be used in the emulsion polymerization in the present invention include acrylic esters such as methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate; methyl methacrylate, and methacrylate. Examples include methacrylic acid esters such as ethyl acid.

In the present invention, other polymerizable unsaturated monomers that can be copolymerized with the above-mentioned acrylic monomers can also be used.

Examples of such polymerizable unsaturated monomers include maleic acid,
Esters of fumaric acid and itaconic acid: vinyl acetate,
Vinyl esters such as vinyl propionate and vinyl tertiary carboxylate; Aromatic vinyl esters such as styrene and vinyltoluene; Heterocyclic vinyl compounds such as vinylpyrrolidone; Vinyl chloride, acrylonitrile, vinyl ether, vinyl ketone, vinyl amide etc.; halogenated vinylidene compounds such as vinylidene chloride and vinylidene fluoride; α-olefins such as ethylene and propylene; and dienes such as butadiene.

In addition, as the polymerizable unsaturated monomer having a reactive polar group, glycidyl acrylate, glycidyl methacrylate-1
~, glycidyl compounds such as allyl glycidyl ether; vinyl trichlorosilane, vinyl 1-ethoxysilane, vinyl tris(β-methoxyethoxy)silane, T
- Silane compounds such as methacryloxypropyltrimethoxysilane, nialic acid, methacrylic acid, maleic acid or its half ester, fumaric acid or its half ester,
Carboxyl compounds such as itaconic acid or its half ester, chloric acid; β-didroxyethyl acrylate
Examples include hydroxyl compounds such as 1 to β-hydroxyethyl methacrylate-13; amine compounds such as alkylamino acrylate and alkylamino methacrylate 1 to 1.

In the present invention, conventionally known surfactants (emulsifiers) used in emulsion polymerization can be used. Anionic emulsifiers such as sodium dodecylbenhine sulfate, sodium dodecylbenzene sulfonate, alkylaryl polyether sulfate, etc.; polyoxyethylene lauryl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene-polyoxypropylene block Nonionic emulsifiers such as copolymers; cationic emulsifiers such as cetyl l to rimedyl ammonium bromide, laurylpyridinium chloride, etc. can be appropriately selected and used. Also, instead of the emulsifier as mentioned above,
Alternatively, it is also possible to use a water-soluble oligomer as a dispersant in combination with an emulsifier. In addition, water-soluble polymeric substances such as polyvinyl alcohol, bitroxyethyl cellulose, etc. may be used in combination with the above emulsifier, or =
14- It is also effective to add it to the emulsion after polymerization.

Synthesis of emulsifiers, water-soluble oligomers, and water-soluble polymer substances
1 amount used is 100 parts by weight of acrylic monomer (
), preferably used in a range of 5 to 10 parts by weight. If the amount is more than this, the water resistance of the final acrylic copolymer aqueous dispersion may be significantly reduced, and if the amount is less than this, the stability during emulsion polymerization and the stability of the resulting emulsion polymer may be affected. There will always be cases where this decreases.

The radical polymerization initiator used in the emulsion polymerization to obtain the aqueous acrylic copolymer dispersion of the present invention includes:
Is it used in normal emulsion polymerization?
Examples of these include potassium persulfate, ammonium persulfate, azobisisobutyronitrile and its salt V salt, and also cumene hydroperoxide, te
Organic peroxides such as rt-butyl hydroperoxide can also be used if desired. Furthermore, known redox initiators are used in combination with these persulfates or peroxides, metal ions such as iron ions, and reducing agents such as sodium sulfooxylate formaldehyde, sodium pyrosulfite, and 1-ascorbic acid. can also be used.

From a practical standpoint, the concentration during emulsion polymerization is preferably such that the final composition has a solid content concentration of 25 to 65% by weight, and the concentration of ethylenically unsaturated monomers and radical polymerization in the reaction system is preferably 25 to 65% by weight. The initiator can be added by any known method such as batch charging, continuous dropwise addition, and divided addition.

The temperature during the emulsion polymerization may be within the range used in known emulsion polymerizations, and the emulsion polymerization is carried out under normal pressure, or under pressure when a dregs-like ethylenically unsaturated monomer is used.

In the present invention, the aqueous dispersion of the carbonyl group- or amide group-containing acrylic copolymer thus obtained is mixed with an aqueous polyurethane resin whose chain has been extended with a hydrazine derivative, thereby forming a functional bond. Strongly expressed. This bond is caused by an organic reaction between the -NHN H2 group at the end of the polymer molecule of the aqueous polyurethane resin and the carbonyl group or amide group of the aqueous acrylic copolymer dispersion during coating. It is an aqueous coating composition that organically combines the functions of a condensation resin and a radical polymerization resin.

Furthermore, the aqueous coating composition of the present invention not only has the elasticity and abrasion resistance of urethane resins and the weather resistance and toughness of acrylic resins, but also has excellent solvent resistance and other properties. Each resin is significantly improved compared to the resin alone. For example, a coating film obtained from an aqueous urethane resin is easily dissolved in ketones such as methyl ethyl ketone, and a coating film obtained from an aqueous acrylic copolymer dispersion is easily dissolved in toluene and the like. However, an aqueous coating composition that meets the requirements of the present invention is insoluble in both methyl ethyl ketone and toluene solvents.

Furthermore, the heat softening temperature of the aqueous coating composition-17= which met the requirements of the present invention exceeds the heat softening temperatures of the aqueous polyurethane resin, the aqueous acrylic copolymer dispersion, and each individual. Then, it develops characteristics that cannot be obtained at all.

On the other hand, in a mixed system of an aqueous polyurethane resin and an aqueous acrylic copolymer dispersion that lacks even one of the requirements of the present invention, the functional bond obtained in the present invention cannot be obtained.
It is impossible to combine the elasticity and abrasion resistance of urethane resin with the weather resistance of acrylic resin. Further, regarding solvent resistance, no compounding effect was observed, nor was a significant increase in the thermal softening temperature observed.

The mixing ratio of aqueous polyurethane resin and aqueous acrylic copolymer dispersion is 10015 to 5/1 in terms of solid content weight ratio.
It is a requirement of the present invention that it be in the range of 00, and 100/
It is more preferably in the range of 10 to 10/100.

If it deviates from this range, it becomes difficult to combine the properties of the aqueous polyurethane resin and the acrylic copolymer dispersion, making it difficult to obtain a coating film with the characteristics described above. The blending ratio of the water-based polyurethane resin and the acrylic copolymer dispersion can be adjusted within the scope of the present invention to match the required performance, thereby emphasizing the characteristics of the urethane resin or improving the characteristics of the acrylic resin. can be emphasized.

The aqueous coating composition of the present invention uses a composition comprising the aqueous polyurethane resin specified above and an aqueous acrylic copolymer dispersion as a vehicle, and a conventional aqueous coating using an aqueous acrylic copolymer dispersion. It is manufactured in exactly the same manner as the preparation of the drug composition.

That is, pigments, fillers, aggregates, dispersants, wetting agents, thickeners and/or rheology control agents, antifoaming agents, plasticizers, coating aids, organic solvents, preservatives, and antifungal agents. , pH adjusters, rust preventives, etc., are selected and combined according to their respective purposes, and made into paints using conventional methods.

Examples will be given below to explain the present invention in more detail,
The present invention is not limited only to the following examples.

In addition, in the following, both parts and % are values based on weight.

Production Example 1 Production of water-based polyurethane resin (A) 1.6-
Hexanediol 1780 C1, Adipic acid 2545
Ω and 567 g of 2,2-dimethylolpropionic acid were mixed, heated to 170° C., and reacted at this temperature for 23 hours to obtain a polyester polyol with an acid value of 60 and an acid (I) of 160.

This polyester polyol was diluted by adding 1815C1 methyl ethyl ketone. 240 g of this polyester polyol solution (I), 220 g of methyl ethyl ketone, and 30 g of 2,2-dimethylolpropionic acid (J
After thoroughly stirring and mixing cyclohexane dimetatool 27C1 at 70°C, 236 g of 4,4"-dicyclohexylmethane diisocyanate was added, the temperature was raised to 80°C, reacted for 6 hours, and then heated to 30°C. It was cooled to obtain a urethane prepolymer solution.

This polyurethane prepolymer solution was prepared in advance at 21°C.
C] 80% aqueous hydrazine solution and 1 to riedylamine 4
0Cl was gradually poured into an aqueous amine solution in 1500 g of ion-exchanged water under stirring to obtain a viscous, translucent product. After removing the solvent at 55°○ under reduced pressure, ion-exchanged water was added to adjust the concentration.
C) A semi-transparent aqueous polyurethane resin (A-1) having a pH of 8.4 and 23 cPs was obtained.

Using the same method as above and using the raw materials shown in Table 1,
Aqueous polyurethane resin (A-
2) to (A-4) were prepared respectively.

(Margin below) 1 22 - Production Example 2 Production of acrylic copolymer aqueous dispersion (B) The following materials were prepared as raw materials.

■Polymerizable monomers acrylic acid? -Ethylhexyl 265g Styrene 165g Acrylonitrile
50g acrylic acid
10g diacetone acrylamide 1
0g ■Surfactants Nucor 7073F (solid content 30%) Wood 1) 50Ω
■Ion exchange water 360 Cl■
Polymerization initiator Ammonium persulfate 2.5g What) Special anion emulsifier manufactured by Nippon Nyukazai 30g of surfactant and 210g of ion-exchanged water were placed in a four-bottle flask, stirring was started, and the temperature was raised to 80°C in a nitrogen stream. , then a polymerization initiator was added. Next, 500 g of polymerizable monomers, 20 q of surfactant, and 150 Ω of ion-exchanged water were mixed to prepare a monomer pre-emulsion, and this monomer pre-emulsion was dropped into the above-mentioned flask over 3 hours.

The reaction temperature at this time was maintained at 80±3°C. After completion of the dropwise addition, the reaction was continued under stirring while maintaining the same temperature range for 2 hours, then cooled and adjusted to pH 3~ with 14% aqueous ammonia.
9, non-volatile content is 55.1%, viscosity is 3000cP
s, aqueous acrylic copolymer dispersion with pH 8.5 (
B-1) was obtained.

Using the same method as above and using the raw materials shown in Table 2,
Acrylic copolymer aqueous dispersions (B-2) to (B-4) having properties shown in Table 2 were obtained.

(Left below) = 24 = -25 Examples 1 to 6, Comparative Examples 1 to 9 Table 3 shows the aqueous polyurethane resin (A) and acrylic copolymer aqueous dispersion (B) obtained in each production example. Aqueous coating compositions (Examples 1 to 6, Comparative Examples 1 to 6) were prepared by blending as shown in
9) was obtained.

(Hereinafter referred to as blank space) Each of the obtained aqueous coating compositions was used alone to test the physical properties of the film. Table 4 shows the results.

(Left below) Test method (1) Water resistance: A sample was applied to a glass plate using a 3 mil applicator to create a film. After drying at room temperature for 3 days, the film was immersed in water.

After soaking at room temperature for 7 days, the film condition was visually judged.

(○...good, △...fair, ×...poor, the same applies hereafter) (2) Alkali resistance: A film prepared in the same manner as in (1) was heated in a 2% hydroxide solution of After 7 days of immersion, the condition of the film was visually judged.

(3) Solvent resistance; a film prepared in the same manner as (1),
The film was immersed in toluene and methyl ethyl ketone for one day, and the film condition was visually determined.

(4) Abrasion resistance: 1 per square meter of standard tile for JFPA standard testing (vinyl asbeth 1 to tile)
Apply the sample to a volume of 0±2 ml.

A test piece coated five times in the same manner was dried for 7 days at room temperature, and then the degree of wear was measured and evaluated using a taper tester (wearing wheel C8-17, load 10,000).

(5) Film strength and elongation: The sample was poured onto a glass plate and dried for 7 days before use. The sample has a film thickness of 0 after drying.
．． Take a sample so that it is 2 mm.

(6) Flow start temperature; 1.5 to 2.0 g of a film dried on a glass plate is used as a sample.

Temperature increase rate 3°C/min, load 30kgf, die 1
Measure the flow start temperature at mmφX 1 mm and Q.

As can be seen from Test Results Table 4, the aqueous coating composition of the present invention has a lower
The solvent resistance and film strength and elongation are much better.

Furthermore, the flow initiation temperature is also characterized by being significantly high, indicating that there is a functional bond between the aqueous urethane resin and the aqueous acrylic copolymer dispersion.

Next, the following coating formulations were carried out using each aqueous coating material-31= composition obtained with the formulations shown in Table 3 to prepare elastic coating agents.

(Composition) Tybake R-930 Ning 4] 100.0 Old-Metrose 90SH-15000 *5) 0.6 Primal 850 *6) 1.05% KT
PP (potassium tripolyphosphate) 2.0 Neugen EA-1
20*7) 1,07tejJ/-/L7SX-568*8)2.5 Ethylene glycol 10.0 Water
35.228% ammonia water 1. Disperse the above formulation in a high speed disperser and add the following formulation.

39% emulsion loquat of each aqueous coating composition) 391.0 Texanol 26.4 Xylene
6.6 Adekanol [Kawa-420
Size 0) / Water -172 (adjusted by paint viscosity) -32 ~ Total 57
7.3N, V (%)
43.7pvc (%)
15.2PWC (%)
39.6*4) Rutile type titanium oxide; 6 Hara Sangyo (*
5) Methyl cellulose; Shin-Etsu Chemical Division *6) Polycarboxylic acid type dispersant; Rohm & Haas Company (USA) *7) Surfactant; Daiichi Kogyo Seiyaku NX *8) Antifoaming agent; Asahi Denka Min*9 )Adjust according to the non-volatile content of the emulsion (%)10
) Thickener: Asahi Denka Hashi The applied physical properties of the aqueous coating compositions of Examples 1 to 6 and Comparative Examples 1 to 9 were tested using the above coating formulations.

Table 5 shows the results.

(Left below) Test method Paint viscosity: B1 type 4 ppm paint viscosity (cPs) Paint film gloss: Coated on a glass plate with a 3 mil applicator, 1
After drying in the sun, measure the 60° reversal rate (%).

JIS A6910: Elongation rate: A test piece was prepared so that the coating film thickness would be about 1 mm on trial, and then cured according to the JIS elongation test method and punched out using a No. 2 dumbbell.

(Coating → Curing for 7 days → Curing for 7 days on the back side → Punching) Deterioration during elongation: The above specimen was punched out using a No. 1 dumbbell.

Adhesion strength: Acrydic 53-4 as a primer
After drying for 3 hours, the sample was applied according to the test method, and after 14 days of curing, the four sides of the test specimen used to test the adhesion strength after being submerged in water were painted with vinyl chloride resin paint 3 days before the end of curing. It was crowded. A two-component poxy adhesive was used as the adhesive.

Resistance to repeated heating and cooling: (18t in 20±2°C water (rs→-20±3°○×3
Hrs-+50± 3°CX3HrS) XIO
Recycle water permeability...according to JIS extensibility test method Impact resistance...
・Weather resistance... Coating film strength: Displays the coating film strength at the time of measuring the JIS A6910 elongation rate.

Accelerated weather resistance: Measure the elongation of a coating film at 20°C and -10°C after subjecting the same coating film to the one whose elongation rate was measured to a standard weather meter for 500 hours.

As can be seen from Test Results Table 5, the aqueous coating composition of the present invention exhibits good weather resistance even when pigments are added, and exhibits properties that do not cause deterioration in coating film strength even after immersion in water.

Representative patent attorney Chieko Tateno

Claims (1)

[Claims] (1) Water-based polyurethane resin (A ) and all the carbonyl group-containing monomers or amide group-containing monomers in the constituent monomers of the acrylic copolymer.
0 parts by weight, an aqueous acrylic copolymer dispersion (B) containing at least 0.5 parts by weight, and the solid content weight ratio is (A)/(B) = 100/5 to 5/100. An aqueous coating composition characterized in that: