JP2003055594A - Water-based top coating material composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a top coating material composition which has remarkably more excellent weather resistance than those of conventional water-based top coating materials. SOLUTION: This water-based top coating material composition comprises a water-based fluororesin emulsion and a urethane dispersion in amounts of 50 to 95 wt.% and 50 to 5 wt.% respectively based on the total amount (solid content) of the water-based fluororesin emulsion and the urethane dispersion.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a water-based top coating composition, and more particularly to a water-based top coating composition for urethane waterproof materials.

[0002]

2. Description of the Related Art Conventionally, for the purpose of protecting the waterproof material and making it beautiful, it has been practiced to coat the surface of the waterproof material with, for example, urethane paint. However, organic solvent-based paints are generally used as urethane paints used for such purposes, and in recent years, water-based paints have been strongly demanded from the viewpoint of ensuring the safety of the global environment and work environment.

[0003]

In order to meet the above demands, therefore, research and development of water-based topcoat paints have been advanced, and for example, a water-based resin composition comprising an aqueous solution or dispersion of an acrylic copolymer and a urethane dispersion. The applicant of the present invention has proposed a two-component water-based top coating composition in which a self-emulsifying polyisocyanate is blended as the main agent of the above. Such a two-component water-based top coating composition has good adhesion to a waterproof material as a base material as compared with a conventional water-based top coating composition, and further has sufficient extensibility as a coating film. It is an excellent product that does not cause problems such as cracking when it is turned into

By the way, the topcoat paint for waterproof material always needs to be repainted in order to always exhibit the weather resistance as a topcoat film, but in places where the coating work is difficult, the topcoat paint composition is used. It is desirable to make the repainting interval as long as possible, and it is advantageous in terms of cost that the repainting frequency is small. Therefore, as described above, the main component of the water-based resin composition consisting of the aqueous solution or water dispersion of the acrylic copolymer and the urethane dispersion, the two-component water-based top coating composition containing a self-emulsifying polyisocyanate as a curing agent Further improvement in weather resistance is desired.

[0005]

Means for Solving the Problems As a result of intensive studies conducted by the present inventors in view of such a point, an aqueous topcoat coating composition containing a specific amount of a specific aqueous fluororesin emulsion and urethane dispersion is used. Then, it was found that the weather resistance of the coating film can be remarkably improved without impairing the adhesion and extensibility of the coating film with respect to the waterproof material as the base material, and the present invention has been completed.

That is, the present invention contains an aqueous fluororesin emulsion and a urethane dispersion, and the aqueous fluororesin emulsion is contained in an amount of 50 to 9 relative to the total amount of the aqueous fluororesin emulsion and the urethane dispersion.
5% by weight, urethane dispersion 50 to 5% by weight
Which is a water-based top coating composition.

The water-based top coating composition of the present invention also comprises
In addition to the aqueous fluororesin emulsion and the urethane dispersion, a self-emulsifying polyisocyanate may be further contained.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, the water-based top coating composition of the present invention contains an aqueous fluororesin emulsion and a urethane dispersion. Hereinafter, each component used in the coating composition of the present invention will be described in detail.

First, the aqueous fluororesin emulsion of the present invention is not particularly limited, and any emulsion may be used as long as the object of the present invention is not impaired. However, weather resistance, pigment dispersibility and coating film physical properties are not limited. From the viewpoint, it is preferable to use a copolymer of a fluoroolefin and a hydrocarbon monomer having a hydroxyl group as the aqueous fluororesin.

Here, as the fluoroolefin, a fluoroolefin having about 2 to 4 carbon atoms such as vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene, tetrafluoroethylene, pentafluoropropylene and hexafluoropropylene is preferably adopted. It Perhalo olefins are particularly preferred.

As the hydrocarbon monomer having a hydroxyl group, a vinyl ether monomer or an acrylic monomer can be used. Specific examples thereof include hydroxymethyl vinyl ether, hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, 4-hydroxycyclohexyl vinyl ether, ethylene glycol monoallyl ether, hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate. . Among these, 4-hydroxycyclohexyl vinyl ether is preferably used from the viewpoints of weather resistance, copolymerizability, and the like.

The hydrocarbon monomer having a hydroxyl group preferably has a hydroxyl value of 10 to 100 mgKOH / g, more preferably 15 to 60 mgKOH / g.
Is.

Further, the fluorine-containing copolymer of the present invention is preferably produced by emulsion polymerization because it is excellent in mechanical stability and chemical stability and a uniform dispersion can be obtained. In addition, at the time of emulsion polymerization, from the viewpoint of stability, it is preferable to perform the polymerization in the presence of a monomer having a hydrophilic site. The hydrophilic portion of the monomer having the hydrophilic portion may be ionic, nonionic, amphoteric or a combination thereof. For example, as a nonionic one, Bremmer PE-200 (manufactured by NOF CORPORATION) or Blemmer PME-200 (manufactured by NOF CORPORATION), and as a cationic one, light ester DQ-100 (manufactured by Kyoeisha Chemical Co., Ltd.) and an anionic one As a thing, Eleminor RS-
30 (manufactured by Sanyo Kasei), Antox MS-2N (manufactured by Nippon Emulsifier) and the like can be mentioned.

Examples of the monomer having a hydrophilic moiety include polyethers and polyesters having a radically polymerizable unsaturated group at one end. Among them, those having a vinyl ether type structure at one end are excellent in copolymerizability with the fluoroolefin and are preferably used. In particular, the polyether chain portion is an oxyethylene unit,
Alternatively, it is preferably composed of an oxyethylene unit and an oxypropylene unit, and has an oxyethylene unit in such a proportion that it becomes hydrophilic.

The monomer having such a hydrophilic moiety can be produced by a method such as ring-opening polymerization of a compound having an alkylene oxide or a lactone ring, or reaction of a diol with vinyl ether or allyl ether having a hydroxyl group.

The monomer having a hydrophilic portion is a macromonomer having a hydrophilic chain obtained by radically polymerizing an ethylenically unsaturated monomer and having a radically polymerizable unsaturated group such as vinyl ether or allyl ether at the terminal. It may be. Such a macromonomer is described in Yamashita et al. In Polym. Bull. , 5.335 (1981).

In addition to these, as a copolymerizable monomer,
Acrylamide and its derivative, methacrylamide and its derivative, N-methylolacrylamide derivative, ethyl carbitol acrylate, acrylic acid ester of triethylene glycol monomethyl ether, 2-hydroxyethyl acryloyl phosphate, butoxyethyl acrylate and the like.

The aqueous fluororesin in the present invention may contain, in addition to the above units, units based on a monomer copolymerizable therewith. Examples of such monomers include olefins such as ethylene and propylene, vinyl ethers such as ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether and cyclohexyl vinyl ether, vinyl esters such as butanoic acid vinyl ester and octanoic acid vinyl ester, styrene and vinyltoluene. Vinyl compounds such as aromatic vinyl compounds,
Examples thereof include allyl compounds such as ethyl allyl ether, acryloyl compounds such as butyl acrylate, methacryloyl compounds such as ethyl methacrylate, isopropenyl ethers, unsaturated fatty acids and the like. In particular, olefins, vinyl ethers, vinyl esters, allyl ethers and allyl esters are preferably used. In such a monomer, at least part of hydrogen bonded to carbon may be replaced with fluorine.

In the aqueous fluororesin of the present invention, the polymerized units based on fluoroolefin are 20 to 80.
Polymer units based on a hydrocarbon monomer having a hydroxyl group (in the case of using a monomer having a hydrophilic portion, the total amount of the hydrocarbon monomer having a hydroxyl portion and the monomer having a hydrophilic portion) are 0 at a molar ratio of 0. It is preferably present in a proportion of 1 to 25 mol%.

If the amount of the polymerized units based on the fluoroolefin is too small, the weather resistance will not be sufficiently exhibited, and if it is too large, the water dispersibility will be extremely deteriorated, which is not preferable. Especially 3
It is preferably from 0 to 70 mol%. Further, if the number of polymerized units based on a hydrocarbon monomer having a hydroxyl group (when a monomer having a hydrophilic portion is used, the total of a hydrocarbon monomer having a hydroxyl portion and a monomer having a hydrophilic portion) is too small, water Dispersibility is extremely poor,
On the other hand, if the amount is too large, the weather resistance and water resistance of the coating film deteriorate, which is not preferable. The polymerized unit based on the hydrocarbon-based monomer having a hydroxyl group is particularly preferably 1 to 15 mol%.

The units other than the polymer units based on the fluoroolefin and the monomer having a hydroxyl group are preferably 0 to 70 mol%. If the amount of this unit is too large, the weather resistance is deteriorated, which is not preferable.

The initiation of emulsion polymerization is carried out by adding a polymerization initiator in the same manner as the usual initiation of emulsion polymerization. As such a polymerization initiator, an ordinary radical initiator can be used, and a water-soluble initiator is preferably adopted. Specific examples include persulfates such as ammonium persulfate, redox initiators, and organic initiators such as azobisisobutyronitrile. The amount of the polymerization initiator used can be appropriately changed depending on the type, emulsion polymerization conditions, etc., but normally 0.005 to 0.5 parts by weight is preferably employed per 100 parts by weight of the monomer to be emulsion polymerized. . Further, these polymerization initiators may be added all at once, or may be added in portions if necessary.

For the purpose of raising the pH of the emulsion, p
An H modifier may be used. The addition amount of the pH adjuster is usually about 0.05 to 2 parts by weight, preferably about 0.1 to 2 parts by weight, per 100 parts by weight of the emulsion polymerization medium. The optimum value of the emulsion polymerization initiation temperature is appropriately selected according to the type of the polymerization initiator, but is usually 0 to 100 ° C, particularly 10 to 90 ° C.
C. is preferably adopted. The reaction pressure can be appropriately selected, and is usually 9.8 × 10 ^{-2 to} 9.8 MPa,
Particularly, it is desirable to adopt a pressure of about 1.96 × 10 ^{-1 to} 4.9 MPa.

The aqueous fluororesin emulsion used in the present invention is described in, for example, JP-A 61-26136.
7, JP-A-61-231044, JP-A-62-24
3603, JP-A-63-314202, JP-A-2-
147601, JP-A-3-33148, JP-A-3-
181540, JP-A-3-199179, JP-A-4
It is also described in each publication such as JP-A-33941 and JP-A-4-33942.

Next, the urethane dispersion of the present invention is obtained by reacting a polyol component, an isocyanate component and a polyhydroxycarboxylic acid. In addition, in the present invention, by adding urethane dispersion to the coating composition, it is possible to improve the crack resistance of the coating film during drying and to impart elasticity to the coating film.

The adhesion, extensibility, stain resistance of the coating film,
From the viewpoint of alkali resistance, acid resistance, abrasion resistance and the like, it is preferable to use a polyether polyol as the polyol component. As the polyether polyol, for example, a homopolymer such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol,
A block copolymer, a random copolymer, etc. are mentioned. The weight average molecular weight (Mw) of the polyether polyol is preferably 400 to 5,000, more preferably 700 to 3,000, from the viewpoint of the hydrolysis resistance of the top coating composition and the conformability to the elongation of the waterproof material. is there.

On the other hand, the isocyanate component is preferably a non-yellowing type of aliphatic or alicyclic diisocyanate. Examples of these include hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, lysine diisocyanate, isopropylidene bis (4-cyclohexyl isocyanate), hydrogenated xylylene diisocyanate, dicyclohexyl diisocyanate and the like. Among these, hexamethylene diisocyanate, isophorone diisocyanate, and hydrogenated xylylene diisocyanate are particularly preferable.

The polyhydroxycarboxylic acid used here is introduced to improve the dispersibility of polyurethane in water. Specifically, dimethylolpropionic acid, dimethylolbutanoic acid, 2,2-dimethylol butyric acid, 2,2-dimethylol valeric acid, etc. can be mentioned. Among these, it is particularly preferable to use dimethylolbutanoic acid in consideration of the compatibility with the acrylic copolymer.

As a specific method for producing the urethane dispersion of the present invention, first, an organic solvent which is inert to isocyanate groups such as dioxane, acetone, methyl ethyl ketone, N-methylpyrrolidone, and tetrahydrofuran and has a high affinity with water. In this, a polyol component, an isocyanate component and a polyhydroxycarboxylic acid are reacted, then a neutralizing agent / chain extender is appropriately added to the obtained prepolymer, and distilled water is further added to obtain a urethane dispersion.

As the chain extender, polyols such as ethylene glycol and propylene glycol, ethylenediamine, propylenediamine, hexamethylenediamine, tolylenediamine, xylylenediamine, diphenyldiamine, diaminodiphenylmethane, diaminocyclohexylmethane, piperazine, There are aliphatic, alicyclic and aromatic diamines such as 2-methylpiperazine and isophoronediamine, and water, and as the neutralizing agent,
Amines such as trimethylamine, triethylamine, tri-n-propylamine, tributylamine, triethanolamine, sodium hydroxide, potassium hydroxide,
Examples include ammonia.

The urethane dispersion of the present invention preferably has a solid content of 20 to 60% and a pH of 7 to 10. Further, the acid value in the urethane resin is preferably 5 to 50 mgKOH / g per resin solid content, and the hydroxyl value in the urethane resin is preferably 1 to 20 mgKOH / g per resin solid content. Furthermore, the weight average molecular weight of the urethane resin is preferably 1 to 200,000 (in terms of polystyrene).

The amount ratio of the aqueous fluororesin emulsion to the urethane dispersion in the coating composition of the present invention is 50 to 50% for the total amount (solid content) of the aqueous fluororesin emulsion and the urethane dispersion. 95% by weight and 50 to 5% by weight of urethane dispersion. The aqueous fluororesin emulsion is preferably 60 to 90% by weight, the urethane dispersion is 40 to 10% by weight, more preferably the aqueous fluororesin emulsion is 60 to 80% by weight,
Urethane dispersion is 40 to 20% by weight.
If the amount of the aqueous fluororesin emulsion is too small, the weather resistance of the coating film deteriorates, while if the amount of the aqueous fluororesin emulsion is too large, the adhesion of the coating film deteriorates.

The coating composition of the present invention can be used as a one-pack type coating composition comprising the above-mentioned aqueous fluororesin emulsion and urethane dispersion.
Furthermore, a self-emulsifying polyisocyanate may be used as a curing agent, and a two-pack type coating composition may be prepared by blending this with a main component composed of an aqueous fluororesin emulsion and urethane dispersion. In the case of a two-pack type coating composition, the weather resistance, stain resistance and adhesion of the coating film can be further improved.

Here, the self-emulsifying type polyisocyanate is an unreacted monomer obtained by adding an isocyanurate-forming catalyst to an NCO group-terminated prepolymer obtained by adding a polyol to an organic polyisocyanate and introducing an isocyanurate ring structure. It is a self-emulsifying polyisocyanate having hydrophilicity, which is obtained by reacting a hydrophilic surfactant having an active hydrogen group capable of reacting with an NCO group. The self-emulsifying polyisocyanate of the present invention is prepared by adding a polyol and a hydrophilic surfactant having an active hydrogen group capable of reacting with an NCO group to an organic polyisocyanate and then adding an isocyanurate-forming catalyst to the isocyanurate ring. The structure may be introduced and unreacted monomers may be removed.

Specific examples of the organic polyisocyanate used in the present invention include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,
4'-diphenylmethane diisocyanate, 2,4'-
Diphenylmethane diisocyanate, 4,4'-diphenyl ether diisocyanate, 2-nitrodiphenyl-4,4'-diisocyanate, 2,2'-diphenylpropane-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4 , 4'-diisocyanate,
4,4'-diphenylpropane diisocyanate, m-
Aromatic isocyanates such as phenylene diisocyanate, p-phenylene diisocyanate, naphthylene-1,4-diisocyanate, naphthylene-1,5-diisocyanate, 3,3'-dimethoxydiphenyl-4,4'-diisocyanate; 1,6-hexamethylene Aliphatic isocyanates such as diisocyanate, 1,4-tetramethylene diisocyanate, lysine diisocyanate; araliphatic diisocyanates such as xylylene-1,4-diisocyanate, xylylene-1,3-diisocyanate; isophorone diisocyanate, water-added tolylene diisocyanate, water Alicyclic diisocyanates such as added xylene diisocyanate, water-added diphenylmethane diisocyanate, and water-added tetramethyl xylene diisocyanate; and this Like compounds and NCO-terminated compounds by reaction with an active hydrogen group-containing compound.

Further, instead of the above-mentioned polyisocyanate obtained by adding a polyol to an organic isocyanate and further adding an isocyanurate-forming catalyst to introduce an isocyanurate ring structure, a polymer of the diisocyanate or a bifunctional or higher functional polyol is used. You may use the polyisocyanate obtained by reaction with the diisocyanate or polymeric body of. That is, any of the polymer of polyisocyanate and the polyol adduct of polyisocyanate can be used in the present invention. Further, it may contain an isocyanate modified product by a reaction of these compounds, for example, a uretdione formation reaction, a carbodiimidization reaction, a uretonimine formation reaction, a buret reaction and the like. These polyisocyanates can be used alone or as a mixture of two or more kinds.

Among these polyisocyanates, aliphatic or alicyclic polyisocyanates are preferable in view of water dispersion stability, stability of NCO group after water dispersion, and non-yellowing property.

Total NCO of Organic Polyisocyanates of the Invention
Examples of the polyol having reactivity with an isocyanate group for urethanizing a part of the groups (0.5 to 15% by weight) include ethylene glycol, 1,3-butanediol, neopentyl glycol and 2,2-diethyl- 1,3-propanediol, 2-n-butyl-2-ethyl-1,3
-Propanediol, 2,2,4-trimethyl-1,3
-Pentanediol, 2-ethyl-1,3-hexanediol, 2-n-hexadecane-1,2-ethylene glycol, 2-n-eicosane-1,2-ethylene glycol, 2-n-octacosane-1,2. -Ethylene glycol, water-added bisphenol A, dipropylene glycol, 3-hydroxy-2,2-dimethylpropyl-3-
Hydroxy-2,2-dimethylpropionate and the like can be mentioned. The molecular weight of these is preferably 62 to 3,000, more preferably 100 to 1,000. By introducing these polyols, the compatibility with the aqueous solution or dispersion of the acrylic copolymer can be improved.

The method for producing the self-emulsifying polyisocyanate of the present invention may be carried out according to a known method, generally in the absence of a solvent. If necessary, a conventional inert solvent, a catalyst, etc. may be used. Can also be used, generally 50-1
It is carried out at a moderately elevated temperature of 00 ° C.

In the present invention, in addition to the above components,
Ingredients required for paint, such as pigments, dyes, dispersants,
Leveling agents (surfactants), ultraviolet absorbers, antioxidants, film-forming aids, preservatives, fungicides, defoamers, pH adjusters, light stabilizers, inorganic and organic fillers, plasticizers, lubricants ,
An antistatic agent, a reinforcing material and the like may be appropriately contained within a range that does not impair the object of the present invention.

If necessary, other substances such as a viscosity modifier, an anti-gelling agent and an organic solvent may be added to the curing agent comprising the self-emulsifying polyisocyanate (C) of the present invention. it can.

The coating composition of the present invention can be produced by adding urethane dispersion to an aqueous fluororesin emulsion and stirring and mixing at 500 to 1000 rpm for 5 to 10 minutes using a dissolver.

When a self-emulsifying polyisocyanate, which is a curing agent, is added to the main component of an aqueous resin composition containing an aqueous fluororesin emulsion and a urethane dispersion, the pot life is It is preferable to mix both of them just before use as a paint.

When the self-emulsifying polyisocyanate is blended in the main agent, the NCO content in the self-emulsifying polyisocyanate is determined by the concentration ratio of the base fluorocarbon resin emulsion and the hydroxyl group in the urethane dispersion. That is, in the present invention, the ratio of the hydroxyl groups derived from the aqueous fluororesin emulsion and the urethane dispersion to the NCO in the self-emulsifying polyisocyanate is [NCO] / [OH] = 2/1 to 1/2. Is preferred. If the blending amount of the self-emulsifying polyisocyanate, which is the curing agent, is too large, the weather resistance of the resulting coating film may deteriorate.

The self-emulsifying polyisocyanate may be diluted with an organic solvent before use. The content of the organic solvent is preferably in the range of 0 to 30% by weight. When workability and finish as a water-based paint are emphasized, propylene glycol methyl ether acetate, diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, dimethyl ester mixture of glutaric acid / succinic acid / adipic acid as the organic solvent (trade name) It is preferable to use a high boiling point organic solvent such as: DBE, manufactured by DuPont). Among them, it is particularly preferable to use propylene glycol methyl ether acetate because it facilitates mixing of the curing agent with the main component and facilitates water dispersion of the curing agent itself.

Since the coating composition of the present invention is excellent in adhesion and extensibility (prevention of cracking), which has been difficult to achieve with conventional water-based resins, it is mainly necessary to protect the waterproof material and impart cosmetic properties. It can be used as a top coat paint for waterproof materials such as balconies and rooftops, especially urethane waterproof materials. Further, since the coating composition of the present invention has remarkably excellent weather resistance, it can be used for building exteriors, bridges, vehicles and the like.

[0047]

The present invention will be described in more detail below, but the present invention is not limited to these examples.

<Aqueous Fluorine Resin Emulsion> Fluorine resin emulsion A (trifluoroethylene-vinyl ether copolymer); trade name: FE-3000 (manufactured by Asahi Glass Co., Ltd.), solid content: 50%, viscosity: 5 to 30 mPa. s (20 ° C.) or less, hydroxyl value: 15 mg KOH / g (solid content), pH: 9.

Fluorine resin emulsion B (trifluoroethylene-vinyl ether copolymer); trade name: FE-4200 (manufactured by Asahi Glass Co., Ltd.), solid content: 50%, viscosity: 50 mPa · s (20 ° C.) or less, hydroxyl group Value: 55 mg KOH / g (solid content), pH: 8.

<Acrylic resin> Synthesis method: To 500 g of methyl ethyl ketone, 235 g of methyl methacrylate, 170 g of ethyl acrylate, 25 g of acrylic acid and 70 g of hydroxyethyl methacrylate were sequentially added, and 5 g of azobisisobutyronitrile was used as an initiator. 80 ° C
The solution radical polymerization was carried out for 6 hours. After completion of the reaction, the carboxylic acid present in the obtained polymer was neutralized with dimethylmonoethanolamine. Further, the polymer solution was dispersed in pure water and uniformly dispersed, and then methyl ethyl ketone was removed by distillation under reduced pressure to obtain a water dispersion of an acrylic copolymer. Solid content: 40%, Mw: 45000 (GPC: standard polystyrene conversion), pH: 9, hydroxyl value: 60 mmKOH / g (solid content).

<Urethane Dispersion> Synthesis Method: Isophorone diisocyanate 72.3 g and glycol component 214.8 in a solvent methyl ethyl ketone.
was reacted with g to synthesize a urethane prepolymer having a terminal isocyanate. It was then neutralized with 10.1 g of triethylamine, where isophorone diisocyanate 2
0.2 g and monoethanolamine 0.8 g were added to water 709.
An aqueous solution dissolved in g was added dropwise to carry out a chain extension reaction and water dispersion. When a uniform dispersion liquid was formed, methyl ethyl ketone was removed by distillation under reduced pressure to obtain a urethane dispersion. Solid content: 30%, Mw: 50000 (GPC: standard polystyrene conversion), viscosity: 100 to 200 mPa · s (20 ° C.) or less, hydroxyl value: 2.3 mgKOH / g (solid content), pH: 7 to 9.

<Self-emulsifying polyisocyanate (curing agent)> Trade name: AQ-200 (manufactured by Nippon Polyurethane Co., Ltd.).

<Production of Topcoat Coating Composition> (Examples 1 to 7, Comparative Examples 1 to 5) Using the above components, aqueous topcoat coating compositions were produced according to the formulations shown in Table 1. The performance of the obtained topcoat paint,
It measured according to the following method. The measurement results are also shown in Table 1.

[Working time] As used herein, the "working time" means the time after the curing agent is added to the water-based resin composition (main component) until it cannot be applied as a paint, and the physical properties of the coating film. The pot life was calculated from the relationship with. That is, when a coating material that has exceeded the pot life is used, the physical properties of the coating film obtained will deteriorate.Therefore, after mixing the main agent with the curing agent, a coating film is prepared at regular intervals, and the coating film is applied by a tensile test. The time when the elongation / strength of the film decreased was defined as the pot life.

[Dry to touch (tack free time)] 2
At 0 ° C., a topcoat paint was applied onto the urethane waterproof material, and a fingertip was brought into contact with the surface of the paint film at regular intervals immediately after the application. Then, the time (minutes) from the time immediately after the application until the fingertip did not adhere to the coating film was determined.

[Adhesive Strength] A urethane waterproof material, which was aged at 20 ° C. and 65% RH for 3 days, was topped with a top coat paint.
It was applied in an amount of 15 kg / m ² and cured at 20 ° C. and 65% RH for 1 week. A non-woven fabric impregnated with the top-coat paint is further laminated on the top-coat paint after curing to form three layers, and 20
It was aged at 65 ° C. and 65% RH for 1 week. After curing, JIS
A peeling test was performed according to K6301 to determine the adhesion strength (N / mm ² ) of the topcoat paint to the urethane waterproof material.

[Elongation rate] A release paper is laid on a synthetic resin bottom plate, and a waterproof material is poured onto the bottom plate at 1.5 kg / m ² , and 2
It was aged at 0 ° C. and 65% RH for 3 days. Furthermore, apply a top coat paint on this waterproof material, and at 20 ° C, 65% R
After curing and hardening with H for 1 week, it was die-cut into a dumbbell-shaped No. 2 shape to obtain a test piece. Using a tensile tester (Autograph, Shimadzu (manufactured)), the marked line 2 on the obtained test piece
The elongation rate between cm was measured.

[Deterioration during elongation] A release paper was laid on a bottom plate made of a synthetic resin, a waterproof material was poured onto the bottom plate at 1.5 kg / m ² , and cured at 20 ° C. and 65% RH for 3 days. Furthermore, apply a top coat paint on this waterproof material, and
After curing and hardening at 5% RH for 1 week, it was die-cut into a dumbbell-shaped No. 1 to obtain a test piece. The deterioration test of the test piece during elongation was measured according to JIS A6909 7.32. That is, the marked line 40 mm in the test piece is 60 mm
Stretch the test piece until
The sample was left to stand in the curing room for an hour, and was then left to stand vertically for 7 days under the condition of 80 ° C ± 2 ° C. The test piece after being left for 7 days was visually observed for peeling, warpage and twist of the top coating film,
The evaluation was made in the following three grades of ○, Δ and ×. ◯: No cracks are observed in the top coating film Δ: Small cracks are slightly observed ×: Cracks are noticeable

[Initial gloss] JIS K5400 7.6
The initial gloss value (60 ° gloss) of the coating film surface was determined according to the specular gloss measurement method described in 1. A gloss meter manufactured by Nippon Denshoku Industries Co., Ltd. was used to measure the initial gloss value.

[Accelerated weathering resistance] A urethane waterproofing material was applied on a slate plate and aged for a certain period of time, and then an overcoat paint was applied and cured by curing at 20 ° C. and 65% RH for 14 days. The accelerated deterioration test of the obtained test body was performed according to JIS
According to K5400, the measurement was performed using a sunshine weather meter (SWOM). As the test conditions for accelerated deterioration, the temperature inside the tank was adjusted to 63 ± 3 ° C. using a black panel thermometer, and the water injection time during one cycle (120 minutes) was 18 minutes. Irradiation time 1000
The gloss value (60 °) of the coating film after hours, 2000 hours and 3000 hours was measured using a gloss meter of Nippon Denshoku Industries Co., Ltd., and the gloss retention rate with respect to the initial gloss value of the coating film was measured. I asked. It can be said that the higher the gloss retention rate, the better the weather resistance.

[Water resistance] Urethane waterproof material test piece (150
(× 70 × 2 mm) was prepared, and after sufficient curing, an overcoat paint was applied, and cured by curing for 14 days in a standard state of 20 ° C. and 65% RH to obtain a test piece. The obtained test piece was immersed in water at 20 ° C. for 7 days. Immediately after the immersion, the test piece was observed immediately after being taken out and after being left for 2 hours after being taken out. The presence or absence of whitening, swelling, cracking, cloudiness, wrinkles and the like in the coating film after immersion was compared with that of the test piece coating film before immersion. In addition, the thing which does not show a big change in the coating film state of a test piece before and after immersion was set as "no abnormality."

[Acid resistance] A test piece identical to the one used for evaluation of water resistance was prepared, and sulfuric acid was added at 5 w / v% with deionized water.
The test piece was dipped in the liquid prepared in step 7 for 7 days. Immediately after the immersion, and immediately after taking out and after leaving for 2 hours after taking out, the presence or absence of swelling, cracking, peeling and holes of the coating film was visually observed. In addition, the thing which does not show a big change in the coating film state of a test piece before and after immersion was set as "no abnormality."

[Alkali resistance] A test piece identical to the one used for the evaluation of water resistance was prepared, and this test piece was dipped in a solution of sodium carbonate adjusted to 5 w / v% with deionized water for 7 days. It was Swelling, cracking of the coating film on the test piece immediately after being taken out and after being left for 2 hours after being taken out,
Peeling and the presence or absence of holes were visually observed. In addition, the thing which does not show a big change in the coating film state of a test piece before and after immersion was set as "no abnormality."

[0064]

[Table 1]

[0065]

EFFECTS OF THE INVENTION The top coating composition of the present invention is water-based and, therefore, in terms of protecting the global environment and ensuring work safety as compared with the organic solvent-based top coatings that have been generally used conventionally. It's very good. Further, the coating film made of the top coating composition of the present invention has excellent adhesion to the waterproof material as a base material, and further has sufficient extensibility as a coating film, so that the coating film does not crack.

Furthermore, the coating film made of the top coating composition of the present invention is remarkably excellent in weather resistance as compared with the conventional water-based top coating composition. Therefore, when the water-based top coating composition of the present invention is used, the waterproof material can be protected sufficiently and for a long time.

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[Procedure amendment]

[Submission date] September 18, 2001 (2001.9.1)
8)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0035

[Correction method] Change

[Correction content]

Specific examples of the organic polyisocyanate used in the present invention include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,
4'-diphenylmethane diisocyanate, 2,4'-
Diphenylmethane diisocyanate, 4,4'-diphenyl ether diisocyanate, 2-nitrodiphenyl-4,4'-diisocyanate, 2,2'-diphenylpropane-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4 ' -Diisocyanate, 4,4'-diphenylpropane diisocyanate,
m-phenylene diisocyanate, p-phenylene diisocyanate, naphthylene-1,4-diisocyanate, naphthylene-1,5-diisocyanate, 3,3 ′
-Dimethoxydiphenyl-4,4'-diisocyanate and other aromatic isocyanates; 1,6-hexamethylene diisocyanate, 1,4-tetramethylene diisocyanate, lysine diisocyanate and other aliphatic isocyanates; xylylene-1,4-diisocyanate, xylylene- Aroaliphatic diisocyanates such as 1,3-diisocyanate; isophorone diisocyanate, water-added tolylene diisocyanate, water-added xylene diisocyanate, water-added diphenylmethane diisocyanate, water-added alicyclic diisocyanate and the like; and these compounds and activity Examples thereof include NCO group terminal compounds obtained by reaction with a hydrogen group-containing compound.

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[Correction target item name] 0051

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<Urethane Dispersion> Synthesis Method: Isophorone diisocyanate 72.3 g and glycol component 214.8 in a solvent methyl ethyl ketone.
was reacted with g to synthesize a urethane prepolymer having a terminal isocyanate. Then, the mixture was neutralized with 10.1 g of triethylamine, and an aqueous solution of 20.2 g of isophoronediamine and 0.8 g of monoethanolamine dissolved in 709 g of water was added dropwise thereto to carry out a chain extension reaction and water dispersion. When a uniform dispersion liquid was formed, methyl ethyl ketone was removed by distillation under reduced pressure to obtain a urethane dispersion. Solid content: 30%, Mw: 50000 (GPC: standard polystyrene conversion), viscosity: 100 to 200 mPa · s (20 ° C.) or less, hydroxyl value: 2.3 mgKOH / g (solid content), pH: 7 to 9.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Noriyuki Shimura             4-3-1-15 Sakurada, Washinomiya-cho, Kitakatsushika-gun, Saitama Prefecture             −401 (72) Inventor Hiroyuki Kato             1369-1 Minota, Konosu, Saitama Prefecture F-term (reference) 4J038 CD091 CD092 CD111 CD112                       CD121 CD122 CD131 CD132                       DG051 DG052 DG131 DG132                       DG271 DG272 DG321 DG322                       GA03 GA06 LA02 MA08 MA10                       MA12 MA14 NA01 NA03 NA04                       NA12 NA27 PA07 PA18 PB05                       PB07

Claims (2)

[Claims] 1. An aqueous fluororesin emulsion and a urethane dispersion are contained, wherein the aqueous fluororesin emulsion is 50 to 95% by weight and the urethane dispersion is relative to the total amount (solid content) of the aqueous fluororesin emulsion and the urethane dispersion. A water-based top coating composition, which is 50 to 5% by weight. 2. The water-based topcoat coating composition according to claim 1, further comprising a self-emulsifying polyisocyanate.