JP5460752B2 - Paint composition - Google Patents

Description

  The present invention relates to a coating composition suitable for surface finishing of various substrates such as concrete, mortar, siding board, extruded board, metal, porcelain tile, plastic, wood, and plywood.

  Conventionally, buildings, civil engineering structures, etc. have been painted with various paints for the purpose of protecting the enclosure and improving aesthetics, and using aromatic hydrocarbon solvents such as toluene and xylene. Many strong solvent-type paints have been used as media. On the other hand, in recent years, awareness of the environment and health has increased, and the use of such aromatic hydrocarbon solvents is considered in consideration of safety during painting, occupational hygiene, and air pollution. There is an increasing movement to control

  In order to cope with such a movement, it has been demanded that the paint be changed to a weak solvent type paint using an aliphatic hydrocarbon solvent. Such weak-solvent paints are less toxic than strong-solvent paints, and have the advantages of high work safety and low impact on air pollution. It is.

  Such weak solvent type paints are roughly classified into a clear type and an enamel type. Among them, the enamel type is prepared by appropriately blending a white pigment such as titanium oxide and a color pigment such as a red pigment, a yellow pigment, a blue pigment, and a black pigment according to a desired hue. However, with a weak solvent paint, it is difficult to control the behavior when two or more of these pigments are mixed, and the pigment miscibility may be insufficient.

  As a resin used for the weak solvent type paint, for example, JP 2001-270972 A (Patent Document 1) includes a cycloalkyl group-containing polymerizable unsaturated monomer, a hydroxyl group-containing polymerizable unsaturated monomer, and Non-polymerized particles containing copolymer particles obtained by polymerizing a polymerizable unsaturated monomer in the presence of a copolymer obtained by polymerizing a tertiary amino group-containing polymerizable unsaturated monomer or the like. A water-dispersed resin composition is disclosed. Japanese Patent Application Laid-Open No. 2002-121468 (Patent Document 2) discloses a resin composition having a main chain made of a substantially vinyl polymer and having hydrolyzable silicon groups and tertiary amino groups in the molecule. Has been. In these patent documents, it is described that the pigment miscibility is increased by the action of the specific amino group of each resin.

JP 2001-270972 A JP 2002-121468 A

However, even if a resin having a specific functional group as described above is used, depending on various conditions during coating, for example, the coating environment such as temperature and humidity, the dilution ratio and the coating amount of the paint used for coating, etc. May be insufficient, and there is room for improvement in practice.
The present invention has been made in view of the above-described problems, and an object of the present invention is to improve pigment miscibility in an enamel type weak solvent paint.

  As a result of intensive studies in order to achieve the above object, the present inventor puts a reaction product of a specific isocyanate and an amine compound into a weak solvent-type paint in which two or more color pigments are mixed. The present inventors have found that this is an effective means and have completed the present invention.

That is, the present invention has the following characteristics.
(A) Solvent-soluble resin and / or non-aqueous dispersion resin,
(B) at least two kinds of coloring pigments,
(C) Reaction of isocyanate (p ′) having at least two isocyanate groups and having a weight average molecular weight of 600 or less and having a lysine skeleton with a primary amine compound (q) having one amino group The product is an essential component, and (B) component is included in an amount of 5 to 500 parts by weight and (C) component is included in an amount of 0.1 to 30 parts by weight with respect to 100 parts by weight of the solid content of the component (A). The coating composition is characterized in that the molar ratio (p ′) / (q) of the isocyanate group of the component ') and the amino group of the component (q) is 0.5 to 1.2.

  According to the present invention, a weak solvent paint having excellent pigment miscibility can be obtained. The coating composition of the present invention can exhibit stable pigment miscibility even when the conditions during coating vary.

  Hereinafter, modes for carrying out the present invention will be described.

  The coating composition of the present invention is a so-called weak solvent-type coating composition mainly composed of an aliphatic hydrocarbon solvent as a solvent component. 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. 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 that are usually used in paints, but the ratio is preferably less than 50% 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.

  As the solvent in the present invention, one or two or more types of aliphatic carbonization are used so that 50% by weight or more (preferably 60% by weight or more, more preferably 70% by weight or more) of all the solvents becomes an aliphatic hydrocarbon. It is desirable to use a combination of hydrogen. In particular, those which do not contain toluene and xylene and fall under the Fire Service Law Type 4 and Type 2 Petroleum with a flash point of 21 ° C. or higher are preferable in terms of health and safety. If the amount of the aliphatic hydrocarbon is too small, the odor becomes strong and the work safety may be lowered, or lifting may be induced when painting on the old paint film.

  In the coating composition of the present invention, (A) a solvent-soluble resin and / or a non-aqueous dispersion type resin (hereinafter also referred to as “component (A)”) is used as the resin component.

  Among these, the solvent-soluble resin is not particularly limited as long as it is soluble in the above-described aliphatic hydrocarbon solvent, and various resins such as acrylic resin, acrylic urethane resin, acrylic silicon resin, and fluororesin. , Alkyd resin, epoxy resin, etc., or composites thereof can be used.

  An example of a suitable solvent-soluble resin is an acrylic resin obtained by polymerizing a (meth) acrylic acid alkyl ester having 4 or more carbon atoms in the alkyl group and other ethylenically unsaturated monomers. . In such a resin, the solubility in an aliphatic hydrocarbon solvent can be increased by adjusting the copolymerization ratio of a (meth) acrylic acid ester having an alkyl group having 4 or more carbon atoms.

  Specifically, as the alkyl group monomer having 4 or more carbon atoms in the alkyl group, for example, n-butyl (meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, lauryl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, eicosyl (meth) acrylate, dicyclopentanyl (meth) ) (Meth) acrylic acid alkyl ester such as acrylate, (meth) acrylic acid cycloalkyl ester and the like.

  Other ethylenically unsaturated monomers include, for example, hydroxyl group-containing (meth) acrylic acid esters, styrene monomers, alkyl group (meth) acrylic acid alkyl esters having 3 or less carbon atoms, and epoxy group-containing ( (Meth) acrylic acid ester, amino group-containing (meth) acrylic acid ester, oxidation polymerizable group-containing (meth) acrylic acid ester, (meth) acrylonitrile, (meth) acrylamide, hindered amino group-containing (meth) acrylic acid ester, Examples include benzotriazole group-containing (meth) acrylic acid esters and vinyl compounds.

  As a method for producing the solvent-soluble resin, for example, a normal radical polymerization method can be used, and the method is not particularly limited. As a method of polymerizing using a radical polymerization method, a method of mixing the monomer and the polymerization initiator in the presence of a solvent and polymerizing at 50 to 200 ° C. for about 1 to 10 hours may be employed. it can. Examples of the polymerization initiator that can be used include organic peroxides and azo compounds.

  The weight average molecular weight of the solvent-soluble resin in the present invention is usually 10,000 to 400,000, preferably 20,000 to 200,000. When the weight average molecular weight is too small, coating properties such as weather resistance and chemical resistance are likely to be insufficient, and when the weight average molecular weight is too large, the resin becomes highly viscous and practically difficult to form a paint.

  Of the component (A) in the present invention, the non-aqueous dispersion type resin is dispersed as resin particles in the above-mentioned aliphatic hydrocarbon solvent, and has a resin portion that can be dissolved in the aliphatic hydrocarbon solvent; It has both the resin part which does not melt | dissolve.

  Such a non-aqueous dispersion type resin is formed, for example, by forming a polymer (m) insoluble in an aliphatic hydrocarbon solvent in the presence of the aliphatic hydrocarbon solvent and the solvent soluble resin. Can be manufactured. At this time, the same monomer as the solvent-soluble resin can be used in the polymer (m), but the type and ratio of the monomer are insoluble in the aliphatic hydrocarbon solvent. Is selected. Usually, it can be insolubilized by using a (meth) acrylic acid ester having an alkyl group having 2 or less carbon atoms as an essential monomer component and adjusting its copolymerization ratio.

  The weight average molecular weight of the non-aqueous dispersion resin is usually 20,000 to 500,000, preferably 30,000 to 300,000. The average particle size of the non-aqueous dispersion resin is about 100 to 2000 nm.

  In the present invention, any one or both of the above solvent-soluble resins and non-aqueous dispersion resins can be used as the component (A). When the component (A) has a crosslinking reactive group, a curing agent capable of reacting with the reactive group can also be used. For example, when the component (A) has a hydroxyl group, an isocyanate curing agent can be used.

  The glass transition point of (A) component is -5 degreeC-70 degreeC normally, Preferably it is 0 degreeC-50 degreeC. When the glass transition point is lower than −5 ° C., the stain resistance is insufficient, and when it is higher than 70 ° C., satisfactory physical properties such as flexibility and durability are hardly obtained.

The coating composition of the present invention contains at least two (B) color pigments (hereinafter referred to as “component (B)”). (B) As a component, the coloring pigment which can be normally used in a coating material is mentioned. Specifically, for example, titanium oxide, zinc oxide, carbon black, iron black, copper / chromium black, cobalt black, copper / manganese / iron black, molybdate orange, ferric oxide, yellow iron oxide, titanium Inorganic color pigments such as yellow, ultramarine blue, bitumen, cobalt / aluminum blue, chromium green, cobalt green, azo, naphthol, pyrazolone, anthraquinone, perylene, quinacridone, disazo, isoindolinone, benzimidazo Examples include organic coloring pigments such as ron-based, phthalocyanine-based, and quinophthalone-based pigments.
In the present invention, when at least one of the components (B) is titanium oxide and at least one is a color pigment other than titanium oxide, a remarkable effect can be obtained.

  The mixing ratio of the component (B) is usually 2 to 300 parts by weight, preferably 5 to 200 parts by weight with respect to 100 parts by weight of the solid content of the component (A). When titanium oxide is contained in the component (B), the weight ratio of titanium oxide to a color pigment other than titanium oxide is usually 99.5: 0.5 to 10:90, preferably 99.5: 0.5 to 50:50.

The component (C) in the first invention has at least two isocyanate groups, a weight average molecular weight of 600 or less, an isocyanate having a lysine skeleton (hereinafter referred to as “(p ′) component”), and one or more It is a reaction product with the amine compound (q component) which has an amino group.
In the present invention, by blending such a component (C), the pigment miscibility in a weak solvent paint in which two or more of the above-mentioned color pigments are mixed can be stabilized.

  In the component (C) in the first invention, the component (p ′) has a lysine skeleton and the weight average molecular weight is 600 or less, so that the affinity of the component (C) to the aliphatic hydrocarbon solvent is increased. The pigment miscibility improvement effect by (C) component is fully exhibited. When the weight average molecular weight is larger than 600 or when there is no lysine skeleton, the affinity of the component (C) to the aliphatic hydrocarbon solvent is lowered and the effect of improving the pigment miscibility is not sufficiently exhibited.

The component (p ′) is an isocyanate having at least two isocyanate groups (preferably three), a weight average molecular weight of 600 or less (preferably 400 or less, more preferably 300 or less), and having a lysine skeleton. .
Examples of the component (p ′) include isocyanate represented by Chemical Formula 1.
(Chemical formula 1)
_{OCN- (CH 2) 4 -CH-} NCO
│
CO ₂ -X
(X is an alkyl group having 1 to 6 carbon atoms, or -YNCO (Y is an alkylene chain having 1 to 6 carbon atoms))

  Examples of the (p ′) component include lysine diisocyanate and lysine triisocyanate. Specific examples include 2-isocyanatoethyl-2,6-diisocyanate caproate (LTI), 2-isocyanate butyl-2,6-diisocyanate caproate, ethyl-2,6-diisocyanate caproate, and the like. In particular, 2-isocyanatoethyl-2,6-diisocyanate caproate (LTI) as lysine triisocyanate is preferred.

  As the other component (q) constituting the component (C), a compound having one or more amino groups and capable of reacting with the component (p ′) can be used. Examples of the component (q) include primary amine compounds, secondary amine compounds, and tertiary amine compounds. Of these, primary amine compounds are preferred. Specific examples of the primary amine compound include, for example, benzylamine, ethylamine, n-propylamine, sec-propylamine, n-butylamine, sec-butylamine, tert-butylamine, n-pentylamine, α-methylbutylamine, Examples include α-ethylpropylamine, β-ethylbutylamine, hexylamine, octylamine, decylamine, laurylamine, stearylamine, cyclohexylamine, aniline, and hexamethylenediamine. Primary amine compounds include ethanolamine, 6-aminohexanol, p-methoxybenzylamine, methoxypropylamine, 3,4-dimethoxyphenylethylamine, 2,5-dimethoxyaniline, furfurylamine, tetrahydrofurfurylamine, bis It is also possible to use (3-aminopropyl) polytetrahydrofuran. In particular, the component (q) is preferably a primary alkylamine having 2 to 12 carbon atoms (particularly 3 to 10 carbon atoms).

The component (C) can be produced by mixing and reacting the component (p ′) and the component (q). The mixing ratio of the component (p ′) and the component (q) is such that the molar ratio of the isocyanate group of the component (p ′) to the amino group of the component (q) is 0.5 to 2.0 (preferably 0.7 to 1). .5, more preferably 0.8 to 1.2).
Although reaction temperature is not specifically limited, Usually, it is about 0-60 degreeC.

  This reaction can be carried out in the presence of a solvent. As such a solvent, the above-mentioned aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, etc. can be used, among which aliphatic hydrocarbon solvents are preferred. is there.

  Moreover, the said reaction can also be performed in a resin component. As the resin component, the above-described component (A) is preferable. When the component (C) is produced in the resin component, either the component (p ′) or the component (q) is mixed with the resin component in advance and the other is gradually added, or the component (p ′) , (Q) component can be separately mixed with the resin component, and then a method such as a method of mixing them can be employed.

  (C) The mixing ratio of a component is 0.1-30 weight part normally with respect to 100 weight part of solid content of (A) component, Preferably it is 0.2-10 weight part. If it is in such a range, sufficient improvement effect in pigment miscibility can be obtained.

  In addition to the above-mentioned components, various components that can be usually blended in the coating composition can be blended in the coating composition of the present invention to such an extent that the effects of the present invention are not affected. Such components include extender pigments, curing agents, thickeners, plasticizers, preservatives, antifungal agents, antialgae agents, antifoaming agents, leveling agents, pigment dispersants, antiskinning agents, dryers, glosses Examples include quenchers, ultraviolet absorbers, light stabilizers, antioxidants, low-contamination agents, and catalysts.

  Of these, examples of extender pigments include heavy calcium carbonate, clay, kaolin, talc, precipitated barium sulfate, barium carbonate, white carbon, and diatomaceous earth. By appropriately mixing such extender pigments, the glossiness and thickness of the formed coating film can be adjusted.

  A hardening | curing agent can be suitably selected according to the kind of (A) component in this invention. For example, when the component (A) has a hydroxyl group, a curing agent containing an isocyanate compound can be used.

  Examples of the thickener include hydrogenated castor oil, oxidized polyethylene, amide wax and the like. Such a thickener may adversely affect the pigment miscibility and coating film glossiness. However, even if such a thickener is contained in the present invention, it is favorable due to the action of the component (C). Physical properties can be secured. The mixing ratio of the thickener is usually 0.1 to 30 parts by weight, preferably 0.2 to 10 parts by weight, in terms of solid content, with respect to 100 parts by weight of the solid content of the component (A).

  The coating composition of the present invention can be produced by uniformly stirring and mixing the above-described components by a conventional method. When using a curing agent, it is possible to use a two-component form at the time of distribution, and to mix and use at the time of painting.

The coating composition of the present invention can be used for surface finishing of various base materials such as concrete, mortar, porcelain tile, siding board, extruded plate, metal, glass, plastic, wood, plywood and the like. The composition of the present invention can be used mainly for protecting buildings such as buildings and civil engineering structures, and is usually used as a coating material.
When the coating composition of the present invention is applied, it can be applied directly to the base material, or it can be applied after some surface treatment (such as a surface treatment with a sealer, surfacer, filler, putty, etc.). Is possible.

Moreover, the coating composition of this invention can also be diluted with an aliphatic hydrocarbon solvent at the time of coating. The dilution ratio is usually about 0 to 30% by weight. As the coating method, for example, various methods such as brush coating, roller coating, spray coating, roll coater, and flow coater can be used. The coating amount at the time of painting is usually about 0.1 to 0.5 kg / m ² .

  Since 50% by weight or more of the total composition of the present invention is aliphatic hydrocarbon, it can be suitably used for coating on a substrate having an old coating film. This is because when a paint using a solvent having a strong dissolving power is repainted, an aging phenomenon of an old paint film called lifting tends to occur, whereas when aliphatic hydrocarbons are contained in an amount of 50% or more by weight, This is because such a lifting phenomenon hardly occurs.

  Examples are given below to clarify the features of the present invention.

(Reference Example 1)
40 parts by weight of Resin A was charged in a container, 0.3 parts by weight of octylamine was mixed while stirring with a stirring blade, and then 0.4 parts by weight of polyisocyanate was mixed and stirred for 5 minutes. Furthermore, 80 parts by weight of titanium oxide, 160 parts by weight of resin A, 6 parts by weight of amide wax thickener (solid content 20% by weight), 2 parts by weight of silicone antifoaming agent (solid content 30% by weight), metal dryer (Co 8 parts by weight of 0.3% by weight and 3% by weight of Zr) and 10 parts by weight of a ferric oxide dispersion (pigment concentration: 40% by weight) were successively mixed in the usual manner to produce paint 1. The ratio of the aliphatic hydrocarbon in the total solvent of the paint 1 is 70% by weight.
As the resin A, a solvent-soluble acrylic resin (styrene oil fatty acid modified product of styrene / isobutyl methacrylate / 2-ethylhexyl acrylate / glycidyl methacrylate copolymer, modification rate 28 wt%, weight average molecular weight 40000, solid content 50 % By weight, mineral spirit solution). As the polyisocyanate, an isocyanurate structure / allophanate structure combined polyisocyanate (reaction product of hexamethylene diisocyanate and n-butyl alcohol, nonvolatile content: 100 wt%, NCO content: 21 wt%) was used.

・ Painting test 1
After 10% by weight of mineral spirit is added to the paint 1 and diluted, the paint is spray-coated at a coating amount of 0.15 kg / m ² on a slate plate (300 × 300 mm) previously coated with a white primer, After 2 hours, spray coating was performed again at a coating amount of 0.15 kg / m ² . When the appearance of the obtained coating film was confirmed after curing for 3 days, no abnormality was found. Note that the painting work and curing in the painting test 1 were all performed in an environment of a temperature of 23 ° C. and a relative humidity of 50%.
・ Painting test 2
After dilution by adding 25% by weight of mineral spirit to the paint 1, the paint was spray-coated at a coating amount of 0.30 kg / m ² on a slate plate (300 × 300 mm) previously coated with a white primer. When the appearance of the obtained coating film was confirmed after curing for 3 days, no abnormality was found. Note that the painting work and curing in the painting test 2 were all performed in an environment of a temperature of 23 ° C. and a relative humidity of 50%.

Example 1
40 parts by weight of Resin A was charged in a container, mixed with 0.3 parts by weight of octylamine while stirring with a stirring blade, and then mixed with 0.45 parts by weight of 2-isocyanatoethyl-2,6-diisocyanate caproate. Stir for 5 minutes. Furthermore, 80 parts by weight of titanium oxide, 160 parts by weight of resin A, 6 parts by weight of amide wax thickener (solid content 20% by weight), 2 parts by weight of silicone antifoaming agent (solid content 30% by weight), metal dryer (Co 8 parts by weight of 0.3% by weight and 3% by weight of Zr) and 10 parts by weight of a ferric oxide dispersion (pigment concentration 40% by weight) were successively mixed in the usual manner to produce paint 2. The ratio of the aliphatic hydrocarbon in the total solvent of the paint 2 is 70% by weight.
The obtained paint 2 was tested in the same manner as in Reference Example 1. In Example 1, no abnormality was observed in any test, and the glossiness was the same as in Reference Example 1.

(Comparative Example 1)
200 parts by weight of Resin A, 80 parts by weight of titanium oxide, 8 parts by weight of an amide wax thickener, 2 parts by weight of a silicone-based antifoaming agent, 8 parts by weight of a dryer, and 10 parts by weight of a ferric oxide dispersion are sequentially mixed in the usual manner. Thus, paint 3 was produced.
The coating 3 obtained by the above method was tested in the same manner as in Example 1. As a result, no particular abnormality was observed in the coating test 1, but in the coating test 2, floating mottle was generated, and the glossiness was lower than that in Reference Example 1.

Claims (1)

A coating composition mainly comprising an aliphatic hydrocarbon solvent as a solvent component,
(A) Solvent-soluble resin and / or non-aqueous dispersion resin,
(B) at least two kinds of coloring pigments,
(C) Reaction of isocyanate (p ′) having at least two isocyanate groups and having a weight average molecular weight of 600 or less and having a lysine skeleton with a primary amine compound (q) having one amino group The product is an essential component, and (B) component is included in an amount of 5 to 500 parts by weight and (C) component is included in an amount of 0.1 to 30 parts by weight with respect to 100 parts by weight of the solid content of the component (A). The coating composition is characterized in that the molar ratio (p ′) / (q) of the isocyanate group of the component ') and the amino group of the component (q) is 0.5 to 1.2.