JP2008031237A - Inorganic paint rich in zinc and method of forming multiple layer coated film using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inorganic paint rich in zinc forming a coated film which can inhibit formation of bubbles without performing a mist coating step and a method of forming the coated film. <P>SOLUTION: The inorganic paint rich in zinc comprises a silicon-based inorganic binder (A), a polyvinyl butyral resin (B), an organic boron compound (C), and a zinc powder (D), and as the compounding ratio of (A) to (B), the SiO<SB>2</SB>component in the component (A):the component (B) is 85:15 to 15:85 (by weight ratio) and the content of the component (C) is 5-30 wt.% based on the total weight of the components (A) and (B), and the component (D) is composed of a zinc powder (d1) having an average particle diameter of 10-50 μm and a zinc powder (d2) having an average particle diameter of less than 10 μm and the compounding ratio of both of (d1) to (d2) is 5:95 to 70:30 (by weight ratio), and furthermore the inorganic paint rich in zinc comprises the component (D) in such a manner that the dried coated film solid content comes to 60-90 wt.%. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an inorganic zinc rich paint capable of forming a coating film capable of suppressing the generation of bubbles without performing a mist coating step, and a multilayer coating film forming method using the same.

  Conventionally, inorganic zinc rich paint has been widely used for heavy anticorrosion coating of steel structures such as ships, bridges, tanks and plants. Since a coating film made of the inorganic zinc rich paint usually has a large number of voids, forming an undercoating film or a topcoating film thereon causes foaming of the coating film or pinholes due to air in the voids. Defects occur. Conventionally, in order to prevent this, before forming the undercoat film, a low-viscosity liquid obtained by diluting the undercoat paint with a large amount of solvent is applied to expel air in the voids of the inorganic zinc rich paint film. The “mist coating process” was performed. However, the mist coat does not completely eliminate the defects, and it has been demanded to suppress generation of bubbles without mist coat from the viewpoint of man-hour reduction.

  For example, Patent Document 1 discloses an inorganic zinc coating composition in which a flake pigment is blended with a silicate color developer and zinc powder. According to this, flake pigments are unevenly distributed on the surface of the coating film, preventing the penetration of the solvent into the gap and preventing the air from being substituted with the air in the gap. is there.

  However, in this method, flake pigments are hardly unevenly distributed on the surface of the coating film in the vertical surface coating, and bubbles are generated in the coating film formed on the upper layer of the coating film. Further, in spray coating, airless chips, filters, strainers, etc. There was a problem that the flake pigments were interrupted in the coating machine.

  Therefore, the present applicant has proposed an inorganic zinc rich paint in Patent Document 2 in which a specific fine powder is used in combination with zinc powder having a specific particle size. According to this, by using a specific fine powder, the inside of the coating film is made dense, so that the porosity in the coating film can be lowered, and the generation of bubbles can be suppressed without performing the mist coating process, and at the time of joint application It is possible to secure a slip coefficient above a certain level.

JP 59-51951 A JP 2002-194284 A

  However, in this method, there is a risk that the coating cracks due to the curing shrinkage of the binder when the coating interval until the next process is long, or bubbles are generated when the paint of the next process is coated with a thick film. It was.

  The objective of this invention is providing the inorganic zinc rich paint which can form the coating film which can suppress generation | occurrence | production of a bubble, without performing a mist coating process, even when the coating material of the next process is applied with a thick film.

  As a result of intensive research to achieve the above object, the present inventors have used zinc powder having different particle diameters, and also used polyvinyl butyral resin in a specific ratio with respect to the inorganic binder, and additionally specified the organoboron compound. By compounding in an amount, an inorganic zinc-rich paint capable of producing a dense coating film with little curing shrinkage was found, and the present invention was completed.

That is, the present invention is an inorganic zinc-rich paint containing (A) a silicon-based inorganic binder, (B) a polyvinyl butyral resin, (C) an organic boron compound, and (D) zinc dust, wherein (A) and (B ) Is a SiO ₂ component in the component (A): (B) component = 85: 15 to 15:85 (weight ratio), and the content of the component (C) is (A) and (B) 5 to 30% by weight based on the total weight of the components, and (D) component consists of (d1) zinc powder having an average particle size of 10 to 50 μm and (d2) zinc powder having an average particle size of less than 10 μm. The ratio is (d1) :( d2) = 5: 95 to 70:30 (weight ratio), and the content of the component (D) is 60 to 90% by weight in the dry coating film solid content. Inorganic zinc rich paint, and based on the inorganic zinc rich paint The present invention relates to a method for forming a multilayer coating film, which comprises coating a material surface, and then applying a coating material for the next step without performing a mist coating step on the material surface.

  According to the inorganic zinc rich paint of the present invention, it is possible to form a coating film that suppresses the generation of bubbles without performing a mist coating process even when the paint of the next process is coated with a thick film.

  In the present invention, the silicon-based inorganic binder (A) is subjected to a condensation reaction in the presence of water and an acid catalyst, such as tetraalkoxysilane, alkyltrialkoxysilane, dialkyldialkoxysilane, partial condensates thereof and / or them. Hydrolyzed initial condensate can be used, and examples of tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetrabutoxysilane, tetraisobutoxysilane, and the like. Examples of the body include silicate 40, M silicate 51 (all manufactured by Tama Chemical Co., Ltd.), methyl silicate 51, ethyl silicate 40, ethyl silicate 48 (all manufactured by Colcoat Co., Ltd.), and alkyltrialkoxysilane. Examples include trimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, ethyltrimethoxysilane, and ethyltriethoxysilane. Examples of the dialkyl dialkoxysilane include dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, and diethyl. Examples include diethoxysilane. These can be used alone or in admixture of two or more. Further, water-dispersed colloidal silica and solvent-dispersed colloidal silica may be used in combination with the alkoxysilanes.

  As the polyvinyl butyral resin (B), conventionally known resins can be used without particular limitation, and in particular, the degree of butyralization is 58 to 77 mol%, preferably 58 to 71 mol%, from the viewpoint of solvent resistance and storage properties. The weight average molecular weight is preferably 30,000 to 300,000, preferably 30,000 to 200,000. Specifically, for example, ESREC BL-1, BL-2, BL-3, BL-S, BX-L, BM-1, BM-2, BM-5, BM-S , BH-3, BX-1, and BX-7 (all manufactured by Sekisui Chemical Co., Ltd.), Denkabutyral # 3000, # 4000, and # 5000 (all manufactured by Denki Kagaku Kogyo Co., Ltd.) Although it is mentioned, it is not limited to these. These polyvinyl butyral resins can be used alone or in admixture of two or more.

  Here, the weight average molecular weight is a value obtained by converting the weight average molecular weight measured with a gel permeation chromatograph (“HLC8120GPC” manufactured by Tosoh Corporation) based on the weight average molecular weight of polystyrene. The columns are “TSKgel G-4000H × L”, “TSKgel G-3000H × L”, “TSKgel G-2500H × L”, “TSKgel G-2000H × L” (both manufactured by Tosoh Corporation, trade name). These were carried out under the conditions of mobile phase: tetrahydrofuran, measurement temperature: 40 ° C., flow rate: 1 cc / min, detector: RI.

The compounding ratio of the silicon-based inorganic binder (A) and the polyvinyl butyral resin (B) is in the range of SiO ₂ component in the component (A): component (B) = 85: 15 to 15:85 (weight ratio). The range is preferably 70:30 to 30:70, more preferably 60:40 to 40:60. In the above blending ratio, if the ratio of the SiO ₂ component is smaller than 15:85, the solvent resistance of the resulting coating film is inferior, and if the ratio of the SiO ₂ component is larger than 85:15, the voids in the coating film increase, which is preferable. Absent.

  In addition to the silicon-based inorganic binder (A) and the polyvinyl butyral resin (B), as a binder component, a metal alkoxide other than silicon-based and boron-based, metal colloid, polyvinyl alcohol resin, polyvinyl acetoacetal as necessary You may mix and use resin etc.

  As the organoboron compound (C), alkyl borate can be applied, and examples thereof include trimethyl borate, triethyl borate, tripropyl borate, tributyl borate, triamyl borate, trihexyl borate, tridecyl borate and the like. Of these, trimethyl borate, triethyl borate, and tributyl borate are particularly preferable. The compounding amount of the organoboron compound (C) is in the range of 5 to 30% by weight, preferably 5 to 20% by weight, more preferably 10 to 15% by weight with respect to the total weight of (A) and (B). If it is less than 5% by weight, the solvent resistance of the resulting coating film is inferior, which is not preferable. If it exceeds 30% by weight, the solvent resistance does not change any more.

  The zinc powder (D) comprises (d1) zinc powder having an average particle diameter of 10 to 50 μm, preferably 10 to 30 μm and (d2) zinc powder having an average particle diameter of less than 10 μm, preferably 1 to 5 μm. Any zinc powder having the above particle diameter can be used without particular limitation, but spherical particles are particularly preferred. The blending ratio of (d1) to (d2) is (d1) :( d2) = 5: 95 to 70:30 (weight ratio), preferably 20:80 to 60:40. . If the weight ratio of (d1) is less than 5:95 in the blending ratio, sufficient friction resistance at the time of coating the joint cannot be obtained, and if the weight ratio of (d1) is greater than 70:30, the coating film Since there are many voids inside, it is not preferable. The zinc powder (D) is preferably contained in the dry coating film in the range of 60 to 90% by weight, preferably 75 to 85% by weight. If the content of the zinc powder (D) is less than 60% by weight, the resulting coating film is inferior in rust resistance, and if it exceeds 90% by weight, the coating film becomes brittle.

  The inorganic zinc rich paint of the present invention contains the components (A), (B), (C) and (D), and may further contain a pigment dispersant (E) as necessary. The pigment dispersant (E) may be solid or liquid at room temperature. As the pigment dispersant (E), an anionic pigment dispersant (for example, aliphatic alcohol sulfate; sulfonated product; alkyl sulfonate; lignin sulfonic acid compound; polycarboxylic acid compound; acrylic acid group, sulfonic acid group or High molecular weight compounds containing phosphate groups), nonionic pigment dispersants (eg oleylaminooleate; high molecular weight compounds containing polyethylene glycol chains or polypropylene glycol chains), amphoteric pigment dispersants (eg amino acids; betaines) ) Etc. can be used. Examples of commercially available products include Disperbyk-102, Disperbyk-110, Disperbyk-111, BYK-P104, BYK-P104S (all manufactured by BYK), Disparon 2150, 1210, DA-1200, DA-375 (both manufactured by Enomoto Kasei Co., Ltd.). Examples of nonionic compounds include Disperbyk-103, Disperbyk-170, Disperbyk-171 (all manufactured by BYK), Disparon DN-900, and DA-550 (all manufactured by Enomoto Kasei Co., Ltd.). The pigment dispersant (E) is 0.01 to 10% by weight, preferably 0.05 to 8% by weight, more preferably based on the total weight of the components (A), (B), (C) and (D). Is preferably contained in the range of 0.1 to 5% by weight from the viewpoint of reducing the viscosity of the paint.

  In the present invention, if necessary, extender pigments, rust preventive pigments and colored pigments can be used as pigment components to the extent that the denseness of the coating film is not impaired. Examples of extender pigments, rust preventive pigments and colored pigments include silica powder, barium sulfate, calcium carbonate, talc, kaolin, clay, titanium oxide, iron phosphide, MIO, lead cyanamide, zinc chromate, zinc phosphate, calcium phosphate, Examples thereof include barium metaborate, zinc molybdate, aluminum molybdate, bengara, cyanine color pigments, carbon black, rutile powder, and zircon powder.

  The inorganic zinc-rich paint of the present invention may be appropriately blended with usual paint additives such as organic solvents, anti-settling agents, anti-sagging agents, and adhesion-imparting agents, if necessary.

  The inorganic zinc rich paint of the present invention can be prepared according to a conventional method. For example, a liquid component containing a binder component and a powder component containing zinc dust are stored in separate containers and mixed together immediately before use. Can be used in The pigment dispersant (E) may be added to the liquid component, or may be added after mixing the liquid component and the powder component.

  The inorganic zinc rich paint of the present invention can be usually applied to the surface of a substrate so that the dry film thickness is 50 μm or more. The coating can be performed by conventionally known means such as air spray, airless spray, and brush.

  In the present invention, the porosity of the coating film obtained as described above is preferably 10% or less, preferably 5% or less from the viewpoint of maintaining the denseness of the coating film and suppressing the generation of bubbles. Here, the porosity is the ratio of the volume of the void portion to the coating film volume, and is a value obtained by the following measurement method.

An inorganic zinc rich paint was applied on the steel plate by spraying to a dry film thickness of 75 μm, dried at room temperature (20 ° C.) for 7 days, and the weight (W 0) of the obtained coated steel plate was measured. Is immersed in liquid paraffin for 1 minute and then pulled up, the liquid paraffin on the surface is immediately wiped off, the weight (W) of the coated steel plate is measured, and the following formula (1) is calculated. The coating volume is the product of the coating area and the dry film thickness.
Porosity (%) = {(W−W0) / specific gravity of liquid paraffin} / coating film volume × 100 (1)

  Moreover, the multilayer coating film formation method of this invention is a method of coating the coating material of the following process, without performing the mist coating process after the process of coating the said inorganic zinc rich paint with respect to the base-material surface. The base material used here is not particularly limited, and can include, for example, iron and an alloy containing iron. The inorganic zinc rich paint can be applied by the above method. The paint for the next step is not particularly limited, and for example, a known undercoat such as an epoxy resin paint can be used.

  A top coat may be further applied on the multilayer coating film thus obtained. The top coating is not particularly limited, and a coating known per se can be used. For example, alkyd resin, acrylic resin, chlorinated rubber, epoxy resin, silicon alkyd resin, urethane resin, Silicon acrylic resin-based or fluororesin-based paints can be used.

Hereinafter, the present invention will be described in more detail with reference to examples. “Parts” and “%” mean “parts by weight” and “% by weight”, respectively.

Production example 1: Production of binder solution 100 parts of ethyl silicate 40 ( manufactured by Colcoat Co.), 72.5 parts of ethanol, 10 parts of water and 5 parts of 2% hydrochloric acid are placed in a reaction vessel at 40C. And stirring was continued for 2 hours to obtain a binder solution (solid content 40%).

Production Example 2: Production of liquid component B-1 To 187.5 parts of the binder liquid, 10 parts of Esrec BM-1 (Note 1) diluted with 15 parts of isopropanol were added, and trimethylborate was further added to 13 parts. .2 parts were added and mixed to obtain liquid component B-1 (solid content 43.5%).

Production Examples 3 to 12: Production of liquid components B- 2 to B-11 According to the formulations shown in Table 1, liquid components B-2 to B-11 were produced in the same manner as in Production Example 2. (Note 1) to (Note 5) in Table 1 are as follows. The liquid components B-1 to B-11 were subjected to the following performance test. The performance test results are also shown in Table 1.
(Note 1) ESREC BM-1: manufactured by Sekisui Chemical Co., Ltd., polyvinyl butyral resin, degree of butyral 65 ± 3%, solid content 100%, weight average molecular weight of about 160,000 (Note 2) ESREC BL-1: Sekisui Chemical Manufactured by Kogyo Co., Ltd., polyvinyl butyral resin, degree of butyral 63 ± 3%, solid content 100%, weight average molecular weight of about 150,000 (Note 3) ESREC BL-10: manufactured by Sekisui Chemical Co., Ltd., polyvinyl butyral resin, butyralized 71 ± 3%, solid content 100%, weight average molecular weight of about 170,000 (Note 4) Disperbyk-110: manufactured by BYK, anionic pigment dispersant, solid content 52%
(Note 5) Disperbyk-170: manufactured by BYK, nonionic pigment dispersant, solid content 30%

Test method for liquid component Crack evaluation 1.0 × 70 × 150mm glass plate, each liquid component prepared to 25% solid content by adding isopropanol was coated with an applicator, and after coating 23 ° C, relative humidity 50 % Of the film was dried for one day to obtain a coating film having a thickness of 15 μm. The surface state of the obtained coating film was evaluated by visual observation (◯: normal, Δ: crack in part of the coating film, x: crack in the entire coating film).
Solvent resistance test Each liquid component prepared to a solid content of 25% by adding isopropanol to a glass plate of 1.0 x 70 x 150 mm was coated with an applicator, and after coating, in an atmosphere of 23 ° C and 50% relative humidity for 1 day. It dried and the coating film with a film thickness of 15 micrometers was obtained. 1 ml of butyl cellosolve was dropped on the coating film, and the state of the coating film after reciprocating 10 times with gauze was evaluated (◯: normal, Δ: surface dissolved, ×: coating film completely dissolved).

Creation of inorganic zinc rich paint
Examples 1-9 and Comparative Examples 1-5
Each component shown in Table 2 was added to the liquid components B-1 to B-11 obtained above and stirred and mixed to obtain each inorganic zinc rich paint. (Note 6) to (Note 9) in Table 2 are as follows. Each inorganic zinc rich paint obtained was subjected to the following performance test. The performance test results are also shown in Table 2.
(Note 6) Zinc powder Special 2: Made by Sakai Chemical Industry Co., Ltd., zinc powder, average particle size 15.5 μm
(Note 7) Zinc powder MCS: Nippon Paint Anticorrosion Coating Co., Ltd., zinc powder, average particle size 8.1 μm
(Note 8) Zinc powder LS-2: Nippon Paint Anticorrosion Coating Co., Ltd., zinc powder, average particle size 3.5 μm
(Note 9) Benton 27: manufactured by Wilber Ells, sagging inhibitor, solid content 100%

Test method for inorganic zinc rich paint Solvent resistance test 3.2 × 70 × 150mm sandblasted steel sheet was coated to a dry film thickness of 75μm, and after coating in an atmosphere of 23 ° C and relative humidity of 50% 1 ml of butyl cellosolve was dropped on the coating film dried for one day, and the state of the coating film after 10 reciprocations with gauze was evaluated (◯: normal, Δ: surface dissolved, x: completely coated film) Dissolves).
Measurement of porosity After spray coating on a sandblasted steel plate of 1.0 x 70 x 150 mm to a dry film thickness of 75 µm, after drying for 7 days in an atmosphere of 23 ° C and 50% relative humidity The porosity was measured according to the above-described porosity measurement method.
Bubble deterrence test 3.2 x 500 x 500 mm sandblasted steel plate Each inorganic zinc rich paint diluted 5% with isopropanol was sprayed to a dry film thickness of 75 μm and dried at room temperature for 7 days. After that, an epoxy resin paint having a viscosity of 10 poise and a non-volatile content of 60% was applied on the obtained coating film by spraying to a dry film thickness of 60 μm or 120 μm and dried at room temperature for 1 day for testing. I got a plate. The number of bubbles (bubbles) and pinholes (per 50 cm ² ) generated on this epoxy coating was visually examined and evaluated according to the following criteria (◯: 0, Δ: 1-3, x: 4 or more) ).

Claims (4)

(A) An inorganic zinc rich paint containing a silicon-based inorganic binder, (B) polyvinyl butyral resin, (C) an organoboron compound and (D) zinc dust, wherein the blending ratio of (A) and (B) is (A) SiO ₂ component in component: (B) component = 85: 15-15: 85 (weight ratio), and the content of (C) component is the total weight of (A) and (B) components The component (D) is composed of (d1) zinc powder having an average particle diameter of 10 to 50 μm and (d2) zinc powder having an average particle diameter of less than 10 μm, and the blending ratio of both is (d1) : (D2) = 5: 95 to 70:30 (weight ratio), and the content of the component (D) is 60 to 90% by weight in the solid content of the dried coating film. paint. The inorganic zinc-rich paint according to claim 1, wherein the pigment dispersant (E) is contained in an amount of 0.01 to 10% by weight based on the total weight of the components (A), (B), (C) and (D). The inorganic zinc rich paint according to claim 1 or 2, wherein the porosity of the obtained coating film is 10% or less. After applying the inorganic zinc rich paint according to any one of claims 1 to 3 on the substrate surface, the paint of the next process is applied on the substrate without performing the mist coating process. Coating film forming method.