JP6076809B2 - Water-based paint composition and refurbishing method using the same - Google Patents

Description

  The present invention is a one-component water-based paint composition that mainly imparts design properties to the inner and outer walls of a building. Specifically, the inner and outer walls of the building have already been finished with an uneven painted wall by a plasterer or the like. The present invention relates to a water-based coating composition that can be applied on a finishing coating material having design properties for the purpose of repairing and a repairing method using the same.

  Conventionally, a sand-wall-like coating composition has been proposed in which a unique sand-wall-like texture is not spoiled by applying it onto an existing design finish with an uneven feeling (Patent Document 1).

  The sand wall coating composition is a coating composition containing a synthetic resin emulsion, a filler, a pigment, and a film-forming aid, and the weight blending part of the filler having an average particle diameter of 1.0 to 40 μm among the fillers. The sand wall paint composition is characterized in that the value obtained by dividing the weight blended part of the filler having an average particle diameter of 70 to 500 μm is 0.1 to 5.0. When the dry state after painting is insufficient, if there is rain or water droplets adhere to the surface of the coating film due to condensation, white streaks may appear when the water droplets subsequently dry out.

  On the other hand, the present applicant has conducted extensive research and has proposed a coating composition that does not produce white streaks based on the results (Patent Document 2). The coating composition is a coating composition in which a synthetic resin emulsion is a binder and includes a filler, a thickener, and a pigment, and the thickener has a carboxymethyl substitution degree of 0.2 to 0.3. This is a coating composition containing water-swellable carboxymethyl cellulose which is water-insoluble.

  However, the coating material composition of Patent Document 2 may cause cracks in portions where the coating film thickness is partially thick, even if the white streaks are not generated, and the thickener When the swellable clay mineral is included, there is a problem that the coating composition may rot if stored for a certain period.

JP 2010-248304 A Japanese Patent Application No. 2012-88929

  The problem to be solved by the present invention is that, when the dry state after painting is insufficient, water droplets adhere to the surface of the coating film due to condensation, and even if the water droplets subsequently dry and disappear, the coating film surface is white. To provide a water-based coating composition that does not cause streak marks, does not crack even at a thick coating, and does not rot even after being stored for a certain period of time. It is in.

The invention described in claim 1 is a coating composition containing a synthetic resin emulsion, a filler, a pigment, a thickener, an anti-corruption agent, and a film-forming aid. The thickener is a water-soluble cellulose ether and carboxymethyl-substituted. Water-insoluble and water-swellable carboxymethylcellulose having a degree of 0.2 to 0.3, hydrophobic fumed silica, free of swellable clay mineral, and water-soluble cellulose ether Provided is an aqueous coating composition characterized by containing 0.05 to 0.15% by weight based on the total amount .

The invention described in claim 2 provides a refurbishing method characterized in that the water-based coating composition according to claim 1 is applied onto an existing finish coating material .

  The water-based paint composition of the present invention and the refurbishing method using the water-based paint composition are such that when there is insufficient dryness after coating, there is rain or water droplets adhere to the coating surface due to condensation, and then the water droplets dry and disappear. However, no white streak marks appear on the surface of the coating film, no cracks occur even in the thick part of the coating film, and it does not rot even if stored for a certain period of time. effective.

  In addition, even if the existing painted wall substrate is uneven due to plastering etc., it adheres along the unevenness, and even if the aqueous coating material composition of the present invention is diluted with water depending on the temperature during construction, Similarly, there is an effect that it adheres along the unevenness and does not sag.

The present invention will be described in detail below.
The aqueous coating composition of the present invention is a coating composition containing a synthetic resin emulsion, a filler, a pigment, a thickening agent, an anti-corrosion agent, and a film-forming auxiliary, and the thickening agent includes water-soluble cellulose ether, carboxymethyl A water-based paint composition comprising a water-insoluble, water-swellable carboxymethyl cellulose having a degree of substitution of 0.2 to 0.3 and hydrophobic fumed silica, and containing no swellable clay mineral, dispersed as required Agent and antifoaming agent are added.

  As the synthetic resin emulsion, acrylic resin emulsion, acrylic urethane resin emulsion, vinyl acetate emulsion, vinyl acetate-acrylic resin emulsion, ethylene-vinyl acetate emulsion, silicon acrylic emulsion, and the like can be used. The number of parts by weight of the synthetic resin emulsion is 5 to 25% by weight, preferably 8 to 18% by weight in terms of resin solid content of the synthetic resin emulsion, based on the entire aqueous coating material composition, and less than 5% by weight is a coating film. The strength is insufficient, and at 25% by weight, the storage stability becomes poor and the drying time becomes long. If it is less than 8% by weight, the coating strength tends to decrease, and if it exceeds 18% by weight, the drying time tends to be delayed.

  As the filler, calcium carbonate and cinnabar sand represented by heavy calcium carbonate can be used, but clay, kaolin, talc, precipitated barium sulfate, barium carbonate and the like can also be used. Among these fillers, the value obtained by dividing the weight blending part of the filler having an average particle diameter of 1.0 to 40 μm by dividing the weight blending part of the filler having an average particle diameter of 70 to 500 μm is 0.1 to 5.0. , More preferably, it is 1.0 to 3.0. If it is less than 0.1, the finish has no unevenness, and if it exceeds 5.0, the concealability is insufficient. If it is less than 1.0, the unevenness tends to decrease, and if it exceeds 3.0, the concealing property tends to decrease. The blending ratio of the filler to the entire coating composition is 20 to 70% by weight, preferably 40 to 60% by weight. If it is less than 20% by weight, the sand wall-like texture is lost and the vapor permeability is lowered. If it exceeds 70% by weight, the coating film strength is insufficient. If it is less than 40% by weight, the vapor permeability tends to decrease, and if it exceeds 60% by weight, the coating strength tends to decrease.

  For pigments, inorganic pigments such as titanium oxide, zinc oxide, carbon black, ferric oxide (valve), lead chromate, yellow lead, yellow iron oxide, etc. can be used. It has excellent properties and is white, so it can be used as the main pigment. The amount of the pigment blended with respect to the entire aqueous coating composition is 0.5 to 20% by weight, preferably 2 to 10% by weight. If it is less than 0.5% by weight, the concealability is insufficient and more than 20% by weight. Then, the storage stability becomes poor. If it is less than 2% by weight, the hiding property tends to be lowered, and if it exceeds 20% by weight, the storage stability tends to be lowered.

  The film formation aid is formulated to promote the fusion of the polymer particles in the emulsion and form a uniform film with the polymer. Ethylene glycol diethyl ether, benzyl alcohol, butyl cellosolve, ester alcohol, and texanol are used. The The number of parts by weight with respect to 100 parts by weight of the resin solid content of the synthetic resin emulsion of the film forming aid is 0.2 to 10.0% by weight, preferably 1.0 to 6.0% by weight, 0.2% by weight. If it is less than%, the curing time will be long, and if it exceeds 10.0% by weight, the pot life will be short and the workability of coating will be hindered. If it is less than 1.0% by weight, the curing time tends to be delayed, and if it exceeds 6.0% by weight, the pot life tends to be short.

  The thickener comprises water-soluble cellulose ether, water-insoluble and water-swellable carboxymethyl cellulose having a carboxymethyl substitution degree of 0.2 to 0.3, hydrophobic fumed silica, and swellable clay. Minerals are not used.

  Water-soluble cellulose ether is obtained by treating cellulose with caustic soda and then reacting with an etherifying agent such as methyl chloride, propylene oxide or ethylene oxide, and is added to prevent cracking of the coating film. In particular, hydroxypropyl methylcellulose having an average number of hydroxyl groups substituted with methoxyl groups per glucose ring unit of 1.4 and an average number of moles of hydroxypropoxyl groups added per glucose ring unit of cellulose of 0.20 is preferred. used. The commercially available hydroxypropyl methylcellulose includes hi-Metroise 90SH (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.).

  The blending amount of the water-soluble cellulose ether with respect to the entire aqueous coating composition is preferably 0.05 to 0.15% by weight, more preferably 0.08 to 0.13% by weight. If it is less than 0.05% by weight, the coating film is cracked, and if it exceeds 0.15% by weight, when the coating film is not sufficiently dried, if water droplets come into contact with it and then dry, white streak marks are generated. If it is less than 0.08% by weight, the coating tends to crack, and if it exceeds 0.13% by weight, when the film is insufficiently dried, water droplets come into contact with it and then dry, leaving white streaks. Tend to.

  Water-insoluble and water-swellable carboxymethylcellulose having a degree of carboxymethyl substitution of 0.2 to 0.3 is a thickener that is insoluble but swells in water, swells in cold and hot water, and does not dissolve . The adjustment method is described in Japanese Patent Application Laid-Open No. 2010-57393, and a commercially available product is Sunrose SLD series (trade name, manufactured by Nippon Paper Chemicals Co., Ltd.).

  The blending amount of the carboxymethyl cellulose with respect to the entire aqueous coating composition is preferably 0.1 to 1.0% by weight, more preferably 0.3 to 0.5% by weight. If it is less than 0.1% by weight, sufficient viscosity cannot be obtained, and if it exceeds 1.0% by weight, the viscosity is too strong and the coating workability is poor. If it is less than 0.3% by weight, there is a tendency that sufficient viscosity cannot be obtained, and if it exceeds 0.5% by weight, the coating workability tends to be poor.

Hydrophobic fumed silica is obtained by chemically treating hydrophilic fumed silica with silane or siloxane, and a specific surface area by the BET method of 100 to 500 m ² / g is preferably used. To commercially available hydrophobic fumed silica, Leorosil PM-20L (trade name, BET specific surface area 100 ± 20 m ² / g, manufactured by Tokuyama Corporation), AEROSIL R972 (trade name, BET specific surface area 110 ± 20 m ² / g) AEROSIL R202 (trade name, BET specific surface area 100 ± 20 m ² / g, manufactured by Evonik).

  The blending amount of the hydrophobic fumed silica with respect to the entire aqueous coating composition is preferably 0.1 to 1.0% by weight, more preferably 0.3 to 0.5% by weight. If it is less than 0.1% by weight, sufficient viscosity cannot be obtained, and if it exceeds 1.0% by weight, the viscosity is too strong and the coating workability is poor. If it is less than 0.3% by weight, there is a tendency that sufficient viscosity cannot be obtained, and if it exceeds 0.5% by weight, coating workability tends to be poor.

  Organic anti-sulfur compounds and isothiazoline compounds are used as anti-corrosion agents, and ACTICIDE EPW (trade name, isothiazoline-based compounds, chemical name: 3- (3,4-dichlorophenyl) -1 is used as an anti-corrosion agent. , 1-dimethylurea (DCMU, Diuron), Methyl-N-benzimidazol-2-ylcarbamate (Carbendizim), 2-n-octyl-4-isothiazolin-3-one (OIT), THOR SPECIALITIES SRA N72 Product name, organic nitrogen-sulfur compound, manufactured by Nippon Enviro Chemicals Co., Ltd.).

  The blending amount of the antiseptic agent with respect to the entire aqueous coating composition is preferably 0.1 to 1.5% by weight, more preferably 0.5 to 1.0% by weight. If it is less than 0.1% by weight, the anti-corrosion effect is insufficient, and if it exceeds 1.5% by weight, discoloration of the coating film may occur. If it is less than 0.5% by weight, the anti-corrosion effect tends to be insufficient, and if it exceeds 1.0% by weight, discoloration of the coating film tends to occur.

  Swellable clay minerals that cannot be used in the present invention are layered silicates of bentonite, smectite, kaolin, sepiolite, and synthetic smectite, which are mainly composed of montmorillonite. The anti-corrosion effect of the inhibitor becomes insufficient, and the aqueous coating composition before application decays during storage.

  In addition to the above-described blending components, an antifoaming agent, a dispersing agent for uniformly dispersing fillers, pigments and the like may be blended in order to eliminate bubbles caused by entrainment in the coating material.

The aqueous coating composition of the present invention is applied onto an existing coating material by a commercially available roller brush, but 0.5 kg / m ^{2 to} 1.0 kg so as not to impair the texture and texture of the existing coating material. preferably it is applied in / m ^2, and as the proper viscosity of the aqueous coating composition, preferably 30~150Pa · s, to such a viscosity, be prepared by adding an appropriate amount of water I can do it.

  Examples and Comparative Examples are shown below, but the present invention is not limited to these Examples.

Examples and Comparative Examples Ultrazol D-22 (acrylic resin emulsion, solid content 55%, viscosity 500-2500 mPa · s / 25 ° C., trade name, manufactured by Gantz Kasei Co., Ltd.) was used as a film forming aid for synthetic resin emulsions. Texanol CS-12 (trade name, manufactured by Chisso Corporation), heavy calcium carbonate SFT-2000 (trade name, manufactured by Sankyo Flour Mills Co., Ltd.) with an average particle diameter D50 of 20 μm for filler A, and average particle diameter for filler B Heavy calcium carbonate K-250 (trade name, manufactured by Asahi Mizue Co., Ltd.) with a D50 of 200 μm, and heavy calcium carbonate BF-200 (trade name, Bihoku powdered) with an average particle diameter D50 of 10 μm in the filler C Manufactured by Kogyo Co., Ltd.), titanium oxide R-820 (trade name, average particle diameter D50; 0.26 μm, manufactured by Ishihara Sangyo Co., Ltd.) as the pigment, and hi-Metrouse 90SH-150 as the thickener A. 00 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), thickener B with Sunrose SLD-F1 (trade name, carboxymethyl substitution degree 0.2 to 0.3, average particle diameter D50; 50 to 60 μm) , Manufactured by Nippon Paper Chemical Co., Ltd.), Leorosil PM-20L (trade name, manufactured by Tokuyama Co., Ltd.) as the thickener C, and Miraclay LFC-25 (trade name, Omi Mining Co., Ltd.) as the swellable clay mineral. Sepiolite Co., Ltd., specific surface area of 122 m ² / g), ACTICIDE EPW and Suraoff 72N as anti-corrosion agents, SN deformer 393 (trade name, manufactured by San Nopco), SN Dispersant 5468 as other additives (Trade name, manufactured by San Nopco Co., Ltd.) were used and mixed uniformly according to the formulation shown in Table 1 to obtain aqueous coating compositions of Example 1 and Comparative Examples 1 to 8.

Evaluation items and evaluation methods

A flexible board (70 mm x 70 mm thickness 8 mm) specified in JISA 5430 is used as the water- strip appearance base, and 0.2 kg of solvent-type chlorinated rubber-based primer JS-410 (trade name, manufactured by Aika Industry Co., Ltd.) is used as the sealer. After coating for 4 hours / m ² and drying for 4 hours or more, each aqueous coating composition of Example 1 and Comparative Examples 1 to 8 was applied at a coating amount of 0.3 kg / m ² using a commercially available medium hair roller. Apply and cure at 23 ° C. and 50% RH for 12 hours. Thereafter, the same water-based coating composition was applied at a coating amount of 0.3 g / m ² in the same manner using a middle roller, and cured at 23 ° C. and 50% RH for 6 hours to obtain a test specimen. The test specimen was left horizontally and ion-exchanged water was dropped. Then, white stripes along the spread of the water drops were evaluated as x, and white stripes were not evaluated as ◯.

Use flexible board as defined in JISA 5430 as crazing base (70 mm × 70 mm thickness 8 mm), solvent-chlorinated rubber undercoat material JS-410 as sealer (tradename, Aica Kogyo Co., Ltd.) 0.2 kg / After applying m ² and drying for 4 hours or more, each aqueous coating composition of Example 1 and Comparative Examples 1 to 8 was applied at a coating amount of 0.4 g / m ² using a commercially available medium hair roller. And cured at 23 ° C. and 50% RH for 12 hours. Thereafter, the same water-based coating composition was similarly applied at a coating amount of 0.4 g / m ² using a middle roller, and cured at 23 ° C. and 50% RH for 6 hours to obtain a test specimen. The case where cracks occurred after drying the coating film was evaluated as x, and the case where cracks did not occur was evaluated as ○.

Storage stability 500 g of each of the aqueous coating compositions of Example 1 and Comparative Examples 1 to 8 were sealed in a 500 cc plastic container and stored for 3 months. It was evaluated.

The viscous aqueous coating composition of Example 1 and Comparative Examples 1 to 8 was adjusted to 23 ° C., the viscosity was measured for BH type viscometer, No. 6 rotor 2rpm and 20 rpm, a thixotropic index of defined JISA6024 Calculated, the thixotropic index is in the range of 3.0 to 6.0, and even when diluted 3% by weight with tap water, the thixotropic index is 3.0 to 6.0 and has the same viscosity. The ones holding the were evaluated as ○, and the others were evaluated as ×.

The evaluation results are shown in Table 2.

Claims (2)

It is a coating composition containing a synthetic resin emulsion, a filler, a pigment, a thickener, an anti-corruption agent, and a film-forming aid, and the thickener is a water-soluble cellulose ether and the degree of carboxymethyl substitution is 0.2 to 0. 3 water-insoluble and water-swellable carboxymethyl cellulose and hydrophobic fumed silica, and containing no swellable clay mineral, An aqueous coating composition containing 0.15% by weight . A water-repellent coating composition according to claim 1 is applied on an existing finish coating material.