JP4597493B2 - Undercoat material composition and coating method using the same - Google Patents

Description

  The present invention relates to an undercoat material composition that can be preferably applied to an inorganic base material surface or an old paint film surface, and a coating method using the same.

Conventionally, inorganic base materials such as concrete, mortar, slate plates, calcium silicate plates and the like are often used as base materials constituting buildings, civil engineering structures, and the like. When coating these surfaces, an undercoat material is usually applied to ensure adhesion and to prevent the coating film from swelling, peeling, floating, etc. over time. In addition, in the case where the coating is applied to the old paint film surface that has deteriorated over time, a primer material is also required. Such undercoat materials are mainly classified into solvent-based undercoat materials and aqueous-based undercoat materials.
Among these, particularly when the surface to be coated is fragile, a solvent-based primer is preferably used. This is because the solvent-based undercoat material is excellent in permeability to the coated surface and has a function of reinforcing the surface layer portion of the coated surface.

However, many of such penetrating solvent-based primer materials are strong solvent-type paints using aromatic hydrocarbon solvents such as toluene and xylene as a medium. Strong solvent type paints have excellent performance in terms of their physical properties, but considering the toxicity to the human body, operational safety, and the effects on air pollution, it is not so much. It is not preferable. In addition, when a strong solvent paint is applied to the old coating surface, there is a risk of lifting.
Recently, there is an increasing trend to suppress the use of such aromatic hydrocarbon solvents.

In order to cope with such a movement, there has been a demand for switching to a weak solvent-type paint containing an aliphatic hydrocarbon solvent as a main solvent. This weak solvent paint is less toxic than the strong solvent paint and has the advantages of high work safety and less influence on air pollution, so it is preferable as an environmentally friendly paint. .
Patent Document 1 describes a weak solvent-type undercoat material containing a specific hydroxyl group-containing resin and an isocyanate compound. However, the undercoat material described in the publication does not have a sufficient film forming performance, and when applied to a surface to be coated with a large amount of suction, a problem that a sealing property cannot be secured unless it is applied many times. There is.

JP 2001-355317 A

  The present invention has been made in view of these points, and provides an undercoat material composition capable of forming a coating film that has both impregnation reinforcement properties and sealing properties, and also has excellent topcoat compatibility. It is the purpose.

  In order to solve such problems, the present inventors have conducted extensive research, and as a result, undercoat materials containing a hydroxyl group-containing non-aqueous dispersion resin, a hydroxyl group-containing soluble modified epoxy resin, and an isocyanate compound as essential components. The composition was conceived. That is, when this primer composition is used, it exhibits excellent impregnation and reinforcement on the surface to be coated, and can form a primer film with high sealing properties with a small number of coatings. It was found that if a material was formed, a coating film excellent in adhesion, finish and the like was obtained, and the present invention was completed.

The present invention has the following characteristics.

1. (A) hydroxyl group-containing non-aqueous dispersion resin, (B) a hydroxyl group-containing soluble modified epoxy resin that is a reaction product of an epoxy resin and an amine compound, (C) an isocyanate compound, and (A) component / (B ) The undercoat material composition characterized in that the solid content weight ratio of the component is 65/35 to 35/65, and 50% by weight or more of the total solvent is an aliphatic hydrocarbon.
2. Further , it contains a dehydrating agent. The primer composition as described.
3. 1. For inorganic substrate surface or old coating surface Or 2. A coating method comprising: applying a primer material composition after applying the primer composition described above.

  According to the present invention, it is possible to obtain an undercoat material composition that can form a coating film that has both impregnation reinforcement properties and sealing properties, and also has excellent topcoat compatibility.

Hereinafter, the present invention will be described in detail based on the embodiments.
The primer composition of the present invention comprises (A) a hydroxyl group-containing non-aqueous dispersion resin and (B) a hydroxyl group-containing soluble modified epoxy resin as a binder, and (C) an isocyanate compound as a curing agent. It is.

[(A) Hydroxyl-containing non-aqueous dispersion type resin]
The component (A) in the present invention is a hydroxyl group-containing non-aqueous dispersion resin (hereinafter referred to as “component (A)”). This (A) component has both the resin part which can be melt | dissolved in a non-aqueous solvent, and the resin part which does not melt | dissolve, and is disperse | distributing to the non-aqueous solvent. The component (A) can be usually obtained by polymerizing various radically polymerizable unsaturated monomers by a conventional method in the presence of a resin soluble in a non-aqueous solvent.
In the composition of the present invention, when the component (A) is contained as an essential component, it is possible to exhibit excellent sealing properties.
The component (A) can be obtained by copolymerizing a hydroxyl group-containing monomer with another copolymerizable monomer. Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 3-hydroxybutyl. (Meth) acrylate, 4-hydroxybutyl (meth) acrylate, di-2-hydroxyethyl fumarate, mono-2-hydroxyethyl-monobutyl fumarate, ethylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate , Polypropylene glycol mono (meth) acrylate, or adducts of these with lactones such as ε-caprolactone and γ-valerolactone, and the like, and by copolymerizing one or more selected from these Can be obtained.
Examples of monomers copolymerizable with a hydroxyl group-containing monomer include (meth) acrylic acid alkyl esters, (meth) acrylamides and derivatives thereof, styrene derivatives, vinyl chloride, vinyl acetate, maleic acid dialkyl esters, fluoroolefins, and reactive silyls. And group-containing vinyl compounds.

As the component (A), those having a weight average molecular weight of 10,000 to 300,000, preferably 50,000 to 150,000 can be used. When the weight average molecular weight is less than 10,000, it is difficult to form a coating film with good sealing properties with a small number of coatings. Moreover, there exists a possibility that coating film physical properties, such as water resistance, may fall. When the weight average molecular weight is larger than 300,000, sufficient film forming performance may not be obtained.
The hydroxyl value of (A) component is 10-100 KOHmg / g normally, Preferably it is 15-80 KOHmg / g. When the hydroxyl value is less than 10 KOHmg / g, sufficient crosslinking density cannot be obtained, and various coating film properties are inferior. When the hydroxyl value is more than 100 KOHmg / g, the pot life is shortened or the adhesion is lowered. It becomes a trend.
The glass transition point of (A) component is -50-100 degreeC normally, Preferably it is -30-80 degreeC.

[(B) Hydroxyl-containing soluble modified epoxy resin]
In the present invention, in addition to the above-mentioned component (A), (B) a hydroxyl group-containing soluble modified epoxy resin (hereinafter referred to as “component (B)”) is used as a binder. In this invention composition, by including this (B) component, the permeability to a to-be-coated surface increases and it becomes possible to fully reinforce the to-be-coated surface layer part.
(B) component produces | generates a hydroxyl group by opening the epoxy group of an epoxy resin. The hydroxyl value of (B) component is 10-300 KOHmg / g normally, Preferably it is 20-200 KOHmg / g.

Examples of the component (B) include a reaction product of an epoxy resin and an amine compound, a reaction product of an epoxy resin and a fatty acid, and the like. Among these, in the present invention, a reaction product of an epoxy resin and an amine compound is particularly preferable.
Examples of the epoxy resin include bisphenol type epoxy resins such as bisphenol A type epoxy resin and bisphenol F type epoxy resin, novolac type epoxy resins such as phenol novolac type epoxy resin, cresol novolak type epoxy resin, bisphenol A novolak type epoxy resin, Copolymerized epoxy resin of bisphenol A type epoxy resin and phenol novolak resin, diglycidyl ether of dihydroxynaphthalene, polyglycidyl ether of mono (di) hydroxynaphthalene novolak, polyglycidyl ether of phenol-divinylbenzene cross-linked phenol resin, bisphenol Polyglycidyl ether of A-divinylbenzene crosslinked phenolic resin, mono (di) hydroxynaphthalene-divinylbenzene bridge Polyglycidyl ethers of type phenol resin. The epoxy equivalent of the epoxy resin is usually about 100 to 10,000.
As the amine compound, a secondary amino group-containing compound is suitable, for example, dialkylamines such as diethylamine, dipropylamine, dibutylamine, N-methylethanolamine, N-butylethanolamine, diethanolamine, dipropanolamine. And alkanolamines. Of these, alkanolamines are preferred as the amine compound.
As a method of reacting the epoxy resin and the amine compound, a known method can be employed. As for the reaction ratio of an epoxy resin and an amine compound, an amino group is about 0.5-2.0 normally with respect to 1 equivalent of epoxy groups.

  In the present invention, the solid content weight ratio of component (A) / component (B) is desirably 95/5 to 5/95, more desirably 85/15 to 15/85, and even more desirably 65/35 to 35/65. Thereby, the coating film excellent in the balance of impregnation reinforcement | strengthening property, sealing performance, and topcoat compatibility can be formed. When the weight ratio of the component (A) is small, the sealing property may be insufficient. Further, when a glossy paint is applied as a top coating material, the glossiness tends to decrease. When the weight ratio of the component (B) is small, the impregnation reinforcement property may be insufficient.

[(C) Isocyanate compound]
In this invention, (C) isocyanate compound is mixed as a hardening | curing agent of (A) component and (B) component. As such a curing agent, for example, Bernock DN-990, DN-991, DN-992 (both manufactured by Dainippon Ink and Chemicals), Duranate TSA (manufactured by Asahi Kasei Kogyo Co., Ltd.), Takenate D-177N (Mitsui Takeda Chemical Co., Ltd.) etc. can be illustrated. Since these hardening | curing agents melt | dissolve in the solvent with weak dissolving power, they can be used conveniently.

In addition, toluene diisocyanate (TDI), 4,4-diphenylmethane diisocyanate (pure-MDI), polymeric MDI, xylylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI), hydrogenated XDI, hydrogenated MDI A derivative of isocyanate monomer such as allophanate, biuret, dimerization (uretidione), trimerization (isocyanurate), adduct formation, carbodiimide reaction, etc., and a mixture thereof are dissolved in a solvent having a strong dissolving power. It is also possible to use it.
In addition, as (C) component in this invention, the polyisocyanate compound which has a 2 or more isocyanate group in 1 molecule normally is used.

  Component (C) has an NCO / OH equivalent ratio of 0.1 to 2.0 (preferably 0.2 to 1.0, more preferably 0.2 to the total amount of component (A) and component (B). It is desirable to mix so that it may become -0.95). At this time, when the NCO / OH equivalent ratio is larger than such a value, the adhesion with the top coating material may be lowered. When the NCO / OH equivalent ratio is small, the crosslinking rate of the coating film becomes low, and the curability and durability tend to be inferior.

[solvent]
The undercoat material composition of the present invention uses a non-aqueous solvent as a solvent, and 50% by weight or more (preferably 60% by weight or more, more preferably 70% by weight or more) of all solvents is aliphatic hydrocarbon. It is a so-called weak solvent type coating composition. Such an aliphatic hydrocarbon solvent has characteristics that it is less toxic than an aromatic hydrocarbon solvent, has high safety in operation, and has little influence on air pollution. Furthermore, since the aliphatic hydrocarbon solvent has an appropriate evaporation rate, it also has an advantageous effect on the impregnation reinforcing property of the primer composition of the present invention.

Examples of the aliphatic hydrocarbon solvent include n-hexane, n-pentane, n-octane, n-nonane, n-decane, n-undecane, n-dodecane, terpin oil, mineral spirit, and the like. .
In addition to such aliphatic hydrocarbon solvents, it is possible to use non-aqueous solvents usually used in paints, but the ratio is less than 50% by weight (preferably less than 40% by weight, more preferably Less than 30% by weight). Examples of such non-aqueous solvents include aromatic hydrocarbon solvents such as toluene, xylene, and solvent naphtha, ethyl acetate, butyl acetate, methyl ethyl ketone, and methyl isobutyl ketone.

  In the present invention, among these non-aqueous solvents, one or two or more kinds are used in combination so that 50% by weight or more becomes an aliphatic hydrocarbon. In particular, those which do not contain toluene and xylene and correspond to the second petroleum having a flash point of 21 ° C. or higher are preferable in terms of safety and health. When the amount of the aliphatic hydrocarbon is less than 50% by weight, the odor becomes strong and the work safety may be lowered, or lifting may occur when coating is performed on an existing coating film. Furthermore, the impregnation reinforcing property may be insufficient.

[Dehydrating agent]
In the primer composition of the present invention, a dehydrating agent can be mixed. By mixing the dehydrating agent, even if the coated surface contains moisture, excellent impregnation reinforcement can be exhibited.

  Examples of the dehydrating agent include trialkyl orthoformate, trialkyl orthoacetate, trialkyl orthoborate, and a monoisocyanate compound. Among these, trialkyl orthoformate includes trimethyl orthoformate, triethyl orthoformate, tributyl orthoformate, and the like. Examples of trialkyl orthoacetate include trimethyl orthoacetate, triethyl orthoacetate, tributyl orthoacetate and the like. Examples of the trialkyl orthoborate include trimethyl orthoborate, triethyl orthoborate, tributyl orthoborate and the like. Examples of the monoisocyanate compound include phenyl isocyanate, p-chlorophenyl isocyanate, benzenesulfonyl isocyanate, p-toluenesulfonyl isocyanate, and isocyanate ethyl methacrylate.

As the dehydrating agent in the composition of the present invention, at least one selected from trimethyl orthoformate, triethyl orthoformate, tributyl orthoformate, trimethyl orthoacetate, triethyl orthoacetate and tributyl orthoacetate is particularly suitable. Such a compound generates an ester and an alcohol by a chemical reaction with water remaining on the coated surface. For example, trimethyl orthoacetate yields methyl acetate and methanol.
When the above-mentioned compound is used as a dehydrating agent, the compound itself is volatile, and the reaction product (ester and alcohol) with remaining water is also volatile and easily volatilizes in the atmosphere. Therefore, it is preferable in that the physical properties of the formed coating film are not adversely affected.

  The content of the dehydrating agent in the composition of the present invention is usually 0.5 to 50 parts by weight, preferably 5 to 5 parts by weight based on 100 parts by weight of the resin solids (total solids of the components (A) and (B)). 40 parts by weight, more preferably 10 to 30 parts by weight. If it is such content, the impregnation reinforcement | strengthening property with respect to a water-containing base | substrate can fully be improved.

[Other ingredients]
In the composition of the present invention, an organic metal compound can be mixed in addition to the above components. Examples of such organometallic compounds include organic tin compounds such as dibutyltin dilaurate, dibutyltin dimaleate, dioctyltin dilaurate, dioctyltin dimaleate, dibutyltin acetate, and tin octylate; aluminum tris (acetylacetonate), titanium bis ( Metal chelate compounds such as acetylacetonate) and zirconium bis (butoxy) bis (acetylacetonate).

  In the composition of the present invention, a color pigment can also be blended. Examples of such color pigments include titanium oxide, zinc oxide, carbon black, ferric oxide (Bengara), lead chromate (molybdate orange), chrome lead, yellow iron oxide, ocher, ultramarine blue, cobalt green and the like. Inorganic pigments such as azo, naphthol, pyrazolone, anthraquinone, perylene, quinacridone, disazo, isoindolinone, benzimidazole, phthalocyanine, and quinophthalone can be used. It is also possible to use extender pigments such as heavy calcium carbonate, clay, kaolin, talc, precipitated barium sulfate, barium carbonate, white carbon, diatomaceous earth.

  In addition to the primer composition of the present invention, various additives that can be usually blended in paints can be blended to such an extent that the effects of the present invention are not affected. Examples of such additives include plasticizers, antiseptics, antifungal agents, algae inhibitors, antifoaming agents, leveling agents, pigment dispersants, anti-settling agents, anti-sagging agents, matting agents, and UV absorbers. can give.

  The solid content of the composition of the present invention is usually 5 to 60% by weight, preferably 10 to 50% by weight. If the solid content is set within such a range, the balance between the impregnation reinforcing property and the sealing property is improved, and the coating workability can be further improved.

[Applicable surface / painting method]
The composition of the present invention is used as an undercoating material at the time of new construction or refurbishment in buildings, civil engineering structures and the like. Applicable coated surfaces include, for example, concrete, mortar, slate plate, calcium silicate plate, ALC plate, extruded plate, slate roof tile, cement roof tile, new roof tile and other inorganic substrate surfaces, and metal bases made of various metals. Various substrate surfaces such as organic substrate surfaces made of materials, plastics, etc., or alkyd resin paints, acrylic resin paints, urethane resin paints, acrylic silicon resin paints, fluororesin systems on these substrate surfaces Examples include the old paint film surface on which various paint films are formed by a paint or the like.
Among these, the composition of the present invention can be particularly preferably applied to an inorganic base material surface or an old coating film surface on these inorganic base materials. In addition, a metal base material is not included in the inorganic base material said here.

In the present invention, the surface of the surface to be coated can be washed as a pretreatment for coating the undercoat material. That is, the undercoat material may be applied after cleaning the surface of the surface to be coated.
In particular, if an undercoating material containing a dehydrating agent is used, even if moisture remains in such a cleaning process, it is possible to sufficiently suppress a decrease in impregnation reinforcement in the undercoating material. Therefore, it is possible to enter the coating process without waiting for the coated surface after washing to dry completely, which is advantageous in terms of shortening the construction period.
In the cleaning step, a method capable of removing contaminants and the like attached to the surface of the surface to be coated may be appropriately employed. Examples of the washing method include high-pressure water washing with water.

Various methods such as brush coating, roller coating, spray coating, roll coater, flow coater and the like can be used as a method for coating the undercoat material. The coating amount at the time of coating is usually 50 to 500 g / m ² , preferably 100 to 300 g / m ² .
The number of times of applying the undercoat material may be appropriately set depending on the surface state of the surface to be coated, but is usually 1 to 2 times. With the undercoat material of the present invention, a coating film having both impregnation reinforcing property and sealing property can be formed even with such a small number of coatings.
The drying time of the primer is usually 3 hours or longer.

After the primer is dried, various topcoats can be applied.
The top coating material is not particularly limited as long as it has a cosmetic property, and various materials can be used. Specific examples include alkyd resin paints, acrylic resin paints, urethane resin paints, acrylic silicon resin paints, fluororesin paints, and the like. These topcoat materials are preferably weak solvent paints or water-based paints.
The top coating material may be finished with one layer, or two or more layers may be laminated and finished.

  Examples and Comparative Examples are shown below to clarify the features of the present invention.

(Manufacture of primer materials)
Undercoat materials 1 to 10 were produced with the formulations shown in Table 1, and the following tests were performed. In addition, the following were used as a raw material at the time of manufacturing a primer.

Resin 1: Hydroxyl-containing non-aqueous dispersion type resin (monomer composition: MMA, EA, St, 2-EHA, i-BMA, 2-HEMA, solid content: 50% by weight, hydroxyl value: 20 KOHmg / g, weight average molecular weight : 80000, glass transition temperature: 35 ° C, solvent: mineral spirit)
Resin 2: Hydroxyl-containing soluble resin (monomer composition: St, 2-EHA, i-BMA, 2-HEMA, solid content: 50% by weight, hydroxyl value: 20 KOH mg / g, weight average molecular weight: 20000, glass transition (Temperature: 35 ° C, solvent: mineral spirit)
Resin 3: hydroxyl group-containing soluble resin (monomer composition: MMA, St, n-BA, 2-HEMA, solid content: 50% by weight, hydroxyl value: 20 KOHmg / g, weight average molecular weight: 40000, glass transition temperature: 50 ℃, solvent: xylene, butyl acetate)
Resin 4: Hydroxyl-containing soluble modified epoxy resin (dialkanolamine adduct of phenol novolac epoxy resin, solid content: 50 wt%, hydroxyl value: 105 KOH mg / g, weight average molecular weight: 2000, solvent: mineral spirit)
Curing agent: isocyanate compound (solid content: 80% by weight, NCO content: 15% by weight)
・ Dehydrating agent: trimethyl orthoacetate However, MMA: methyl methacrylate, EA: ethyl acrylate, St: styrene, 2-EHA: 2-ethylhexyl acrylate, n-BA: n-butyl acrylate, i-BMA: i-butyl methacrylate, 2-HEMA: 2-hydroxyethyl methacrylate

(Test method)
(1) Impregnation reinforcing property The half coat of the calcium silicate plate was brush-coated with a coating amount of 150 g / m ² , and the other half was brush-coated with a coating amount of 300 g / m ² . After curing for 7 days in a standard state (temperature 23 ° C., humidity 50%), the impregnation reinforcement was evaluated by a cross-cut tape method (4 × 4 mm · 25 mass). Evaluation,
A: No peeling B: Break in substrate is less than 2/25 B: Break in substrate is 2/25 or more and less than 5/25 X: Break in substrate is 5/25 or more
In addition, the surface of the calcium silicate plate was washed thoroughly with water, allowed to stand for 2 hours in a standard state, and then the test specimen obtained by brushing the undercoat material at a coating amount of 300 g / m ² was similarly impregnated and reinforcing. evaluated.

(2) Water permeability On one side of the calcium silicate plate, the primer was brushed at a coating amount of 150 g / m ² , and the remaining half was brushed at a coating amount of 300 g / m ² . After curing for 7 days in the standard state, 1 ml of water was spotted on the surface of the test specimen, and the portion was covered with a watch glass, and the state until standing for 24 hours was confirmed. Evaluation,
A: The amount of water did not decrease even after 24 hours. B: Spots remained even after 24 hours. Δ: Spot disappeared after 24 hours. X: Spot disappeared after 3 hours.

(3) Alkali sealing property A primer was applied to the half surface of the calcium silicate plate with a coating amount of 150 g / m ² , and the remaining half surface was brush-coated with a coating amount of 300 g / m ² . After curing for 7 days in the standard state, 1 ml of phenolphthalein aqueous solution was spotted on the surface of the test specimen, and the portion was covered with a watch glass, and the state until standing for 24 hours was confirmed. Evaluation,
A: No change in hue even after 24 hours. O: Change to red-purple after 24 hours. Δ: Change to red-purple after 16 hours. X: Change to red-purple immediately after the spot.

(4) Lifting resistance Two-component weak solvent soluble acrylic urethane resin paint (trade name “Clean Mild Urethane”; manufactured by SK Kaken Co., Ltd.) was applied to a tin plate by spraying as a test substrate. . The test substrate was cut with a 5 × 4 cm cut (X cut) using a cutter, and the presence or absence of lifting when the test paint was brushed on the X cut portion was visually confirmed. Evaluation,
A: No lifting occurred. O: Slight lifting occurred in the X-cut portion. Δ: Lifting occurred in the X-cut portion. X: Lifting occurred in the plane portion other than the X-cut portion.

(5) Top coat compatibility A primer was applied to the calcium silicate plate with a coating amount of 300 g / m ² . After curing for 3 hours in the standard state, a top coating material (trade name “Clean Mild Urethane”; manufactured by SK Kaken Co., Ltd.) was applied with a brush at a coating amount of 200 g / m ² . After curing for 7 days in the standard state, the top coat compatibility was evaluated by measuring the specular gloss (measurement angle: 60 degrees) of the coating film surface. Evaluation,
A: Specular gloss of 70 or more ◯: Specular gloss of 65 or more and less than 70 Δ: Specular gloss of 60 or more and less than 65 ×: Specular gloss of less than 60

(Test results)
As the test results are shown in Table 2, in Examples 1 and 2 , good results could be obtained in any test.
On the other hand, Comparative Example 1 and Comparative Example 3 were inferior in sealing properties. In Comparative Example 2, the impregnation reinforcing property was inferior. In Comparative Example 4, the sealing performance and the lifting resistance were inferior.

Claims (3)

(A) hydroxyl group-containing non-aqueous dispersion resin, (B) a hydroxyl group-containing soluble modified epoxy resin that is a reaction product of an epoxy resin and an amine compound, (C) an isocyanate compound, and (A) component / (B ) The undercoat material composition characterized in that the solid content weight ratio of the component is 65/35 to 35/65, and 50% by weight or more of the total solvent is an aliphatic hydrocarbon. The primer composition according to claim 1, further comprising a dehydrating agent. A coating method, comprising: applying an undercoat material composition to an inorganic base material surface or an old coating film surface, and then applying an overcoat material.