JPH07258599A - Composition for highly weather-resistant acrylic resin coating material - Google Patents

Abstract

PURPOSE:To obtain the title composition for a coating material which can give a film having good weather resistance, good scratch resistance and marked durability to especially long-term thermal deterioration. CONSTITUTION:The title composition comprises at least one binder selected from among an acrylic polyol resin, an isocyanate compound having at least two functional groups, a blocked isocyanate compound and a melamine compound, at least one inorganic organosol selected from among a metal oxide in which the metal is selected from the group II metals (Mg, Ca, Sr and Ba), in the long-form periodic table of elements, the group III metals (B, Al, Ga, In, Tl, Sc, Y, La and Ac), the group IV metals (Si, Ge, Sn, Pb, Ti Zr and Hf), the group V metals (As, Sb, Bi, V, Nb and Ta), the group VI metals (Te, Po, Cr, Mo and W), the group VII metals (At, Mn, Tc and Re) and the group VIII metals (Fe, Co, Ni, Ru, Rh, Pd, Os, Ir and Pt), a salt thereof, a siloxane, a metallosiloxane, a silazane, a metallosilazane and a mixture thereof and a solvent, optionally containing a reaction acceleration catalyst and containing 0.001-3wt.%, based on the solid matter, hindered phenol antioxidant and 0.001-3wt.%, based on the solid matter, thioether autoixidant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating composition which is inexpensive and has excellent weather resistance and scratch resistance. In particular, it relates to a coating composition having excellent durability when exposed to heat for a long time.

The paint composition of the present invention is a paint or coating agent for the surface of inorganic substances (steel plate, aluminum plate, glass, roof tile, slate plate, etc.) and organic substances (wood, paper, cellophane, plastics, coating films of organic paints, etc.). Is useful as

The steel sheet to be used in the present invention is, for example, a hot rolled steel sheet, a cold rolled steel sheet, an electrogalvanized steel sheet, a hot dip galvanized steel sheet, an alloy plated steel sheet, or a chemical conversion treatment of chromic acid, phosphoric acid or the like on these. The applied products are tinplate, chin-free steel, stainless steel plate, and the like.

Since it is excellent in weather resistance and scratch resistance, particularly in durability when it is heated for a long time, it is used in the fields of transportation vehicles (automobiles, train cars, aircrafts, etc.), construction materials (roofs, rain doys, windows). It is useful for frames etc.)

[0005]

2. Description of the Related Art JP-A-4-173882 discloses a coating composition having excellent weather resistance and scratch resistance. The coating composition is an acrylic polyol resin, an isocyanate compound having two or more functional groups, one or more binders selected from blocked isocyanate compounds and melamine compounds, and the metal is a group II metal ( Mg, Ca, Sr, Ba), Group III metals (B, Al, Ga, In, Tl, Sc, Y, L)
a, Ac), Group IV metals (Si, Ge, Sn, Pb, Ti, Zr, Hf), Group V metals (As, Sb, Bi, V, Nb, Ta), Group VI metals (Te, Po, Cr) , Mo, W), V
Group II metals (At, Mn, Tc, Re) and Group VIII metals (Fe, Co, Ni,
Ru, Rh, Pd, Os, Ir, Pt) and at least one inorganic organosol selected from metal oxide sols and salts of metal oxide sols, siloxanes, metallosiloxanes, silazanes, metallosilazanes, and mixtures thereof. , And a solvent, and optionally a reaction accelerating catalyst.

The coating composition described in JP-A-4-173882 has both weather resistance and hardness.

[0007]

However, although the weather resistance of the coating film of the coating composition is generally excellent, there is a problem in its durability when it is exposed to heat for a long time. For example, when a building material in which such a coating composition is applied on a metal material is used around a roof that is easily exposed to direct sunlight, it is gradually applied by being exposed to a considerably high temperature (60 to 90 ° C) for a long time, especially in summer. Heat deterioration of the film occurs,
The coating film turns yellow over time, and cracks and peeling occur.

[0008]

As a result of intensive studies to solve the above problems, the inventors of the present invention have included an acrylic polyol resin, a binder, an inorganic organosol, and a solvent. It has been found that when a coating composition optionally containing a reaction promoting catalyst contains a hindered phenolic antioxidant and a thioether antioxidant, the durability of the coating film is excellent even when subjected to heat for a long time. The present invention has been completed. The improvement of the durability of this coating film is remarkably large as compared with the case where each of the hindered phenol-based antioxidant or the thioether-based antioxidant is used alone, and it is shown that a synergistic effect is obtained when the both are used in combination. There is.

That is, the present invention relates to an acrylic polyol resin, one or more binders selected from isocyanates having two or more functional groups, blocked isocyanates and melamine, and the metal is a Group II metal (Mg , Ca, Sr, Ba), Group III metals (B, Al, Ga, In, Tl, Sc, Y, L)
a, Ac), Group IV metals (Si, Ge, Sn, Pb, Ti, Zr, Hf), Group V metals (As, Sb, Bi, V, Nb, Ta), Group VI metals (Te, Po, Cr) , Mo, W),
Group VII metals (At, Mn, Tc, Re) and Group VIII metals (Fe, Co, N)
i, Ru, Rh, Pd, Os, Ir, Pt) and one or more inorganic substances selected from metal oxide sols and salts of metal oxide sols, siloxanes, metallosiloxanes, silazanes, metallosilazanes and mixtures thereof. A coating composition containing the organosol and the solvent, and optionally a reaction-promoting catalyst, which contains a hindered phenol-based antioxidant and a thioether-based antioxidant.

The hindered phenolic antioxidant used in the present invention is a compound having a phenol skeleton, and one or both of the phenolic hydroxyl groups has an ortho position of te.
Those substituted with an rt-butyl group are preferred. Examples of compounds that can be used among commercially available products are compound (1) (eg Sumitizer Chemical Co., Ltd. "Sumilyzer GA-80"), compound
(2) (eg "Sumilyzer GM"), compound (3)
(Example: “Irganox MD-1” manufactured by Ciba Geigy)
024 ”), compound (4) (eg, the same“ Irganox 10 ”
10 "), compound (5) (eg," Nogard XL-1 "manufactured by Uniroyal Co., Ltd.) and the like. Compound (1) ~
The structure of (5) is shown below.

[0011]

[Chemical 1]

[0012]

[Chemical 2]

[0013]

[Chemical 3]

[0014]

[Chemical 4]

[0015]

[Chemical 5]

The thioether type antioxidant used in the present invention is also generally called a sulfur type secondary antioxidant, and among them, a thioether having two or more long chain alkyl groups (having 6 or more carbon atoms) in the molecule. Compounds are preferred. Examples of the compound that can be used among commercially available products include compound (6) (eg, “Adeka Stab AO-2” manufactured by Asahi Denka Co., Ltd.).
3 ”), compound (7) (eg,“ IRGANOX 1520 ”manufactured by Ciba-Geigy Co., Ltd.), compound (8) (eg,“ TPM ”manufactured by Sumitomo Chemical Co., Ltd.), compound (9) (eg,“ the same ”). TP-
D ") etc. The structures of compounds (6) to (9) are shown below.

[0017]

[Chemical 6]

[0018]

[Chemical 7]

[0019]

[Chemical 8]

[0020]

[Chemical 9]

If the amount of each antioxidant added is too small, the effect will be lost. Therefore, the lower limit is 0.001% by weight, preferably 0.03% by weight. Therefore, the upper limit is 3% by weight, preferably 1
% By weight.

Examples of the acrylic polyol resin used in the present invention include (1) 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and methacrylic acid.
2-hydroxyethyl, 2-hydroxypropyl methacrylate, allyl alcohol, cinnamic alcohol, crotonyl alcohol, or unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid and ethylene. A hydroxyl group-containing monomer which is a reaction product of glycol, ethylene oxide, propylene glycol, propylene oxide, butylene glycol, 1,4-cyclohexyldimethanol, phenylglycidyl ether, glycidyl decanoate, and (2) acrylic acid Methyl, ethyl acrylate, n-propyl acrylate, isopropyl acrylate,
Acrylic esters such as n-butyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate, such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, methacrylic acid Methacrylic acid esters such as tert-butyl acid and 2-ethylhexyl methacrylate, for example, styrene monomers such as styrene, vinyltoluene, α-methylstyrene; other acrylic acid, methacrylic acid, vinyl acetate, vinyl propionate, acrylonitrile , Vinyl stearate, allyl acetate,
Diallyl adipate, dimethyl itaconate, diethyl maleate, vinyl chloride, vinylidene chloride, ethylene, glycidyl methacrylate, N-methylol acrylamide,
Examples thereof include those obtained by copolymerizing one or two or more copolymerizable α, β-ethylenically unsaturated monomers such as N-butoxymethyl acrylamide, acrylamide, and diacetone acrylamide.

The acrylic polyol resin obtained by combining the above raw materials has a molecular weight of about 1,000 to 500,000,
Preferably about 5,000-100,000, hydroxyl value about 5-300,
Preferably about 10 to 200 are preferably used.

Commercially available acrylic polyol resins include, for example, "Arotane UW2818" manufactured by Nippon Shokubai Kagaku Kogyo Co., Ltd., "Acridic A801, A811, A808" manufactured by Dainippon Ink and Chemicals Co., Ltd., Hitachi Chemical. (stock)
"Hitaroid 2462A, 2405" made by Sumitomo Bayer Urethane Co., Ltd. "Desmophen A160, A165, A260"
Etc.

The binder is selected from isocyanate compounds having two or more functional groups, blocked isocyanate compounds and melamine compounds. These can be added to the acrylic polyol resin either individually or in combination of two or more.

As the isocyanate compound, aliphatic compounds,
Alicyclic, aromatic and other polyisocyanate compounds and their modified products can be used. However, the weather resistance of the coating,
Particularly, in order to prevent yellowing, a so-called non-yellowing polyisocyanate compound containing no isocyanate group directly bonded to the aromatic nucleus is preferable. Examples of the non-yellowing polyisocyanate compound include hexamethylene diisocyanate, 1,4-cyclohexanebis (methylisocyanate), methylenebis (cyclohexylisocyanate), cyclohexylmethane diisocyanate, isophorone diisocyanate, 2-isocyanatoethyl 2,6-diisocyanate hexano Ate, 2,6-diisocyanate methylcaproate, dimeryl diisocyanate, dianisidine diisocyanate, cyanuric acid, isocyanuric acid, and modified products thereof. Examples of the modified product include trimer type, dimer type, prepolymer type, buret type, urea type, and other modified types, and particularly, trimer type, trimethylolpropane-modified prepolymer type, buret type, etc. Modified products are suitable. In some cases, an aromatic yellow modified polyisocyanate compound may be used in place of or together with these yellow-free modified polyisocyanate compounds.

In the present specification, the blocked isocyanate compound means a blocked isocyanate compound which is deblocked under the following curing conditions to generate an isocyanate group, and is produced by blocking the above polyisocyanate compound. You can The blocking agent used for this blocking can be appropriately selected from various known blocking agents depending on the application and curing conditions. For example, lactam-based blocking agents such as ε-caprolactam, acetoxime, methylethylketoxime, methylisoamylketoxime, methylisobutylketoxime, other oxime-based blocking agents, phenol, cresol, catechol, nitrophenol, and other phenolic blocks Agents, isopropanol, trimethylolpropane, other alcohol-based blocking agents, malonic acid esters,
Examples thereof include acetoacetic acid ester and other active methylene-based blocking agents, but are not limited thereto. Preferred blocking agents are, for example, lactam blocking agents and oxime blocking agents.

In general, it is preferable to include an isocyanate compound when used as a room temperature curing type hard coat composition and a blocked isocyanate compound when used as a baking type hard coat composition. However, it may contain a combination of two or more binders.

Examples of commercially available isocyanate type binders include "Coronate 2515" manufactured by Nippon Polyurethane Industry Co., Ltd., "Desmodur BL3175" manufactured by Sumitomo Bayer Urethane Co., Ltd., and the like.

Examples of the melamine compound include dimethylol melamine, trimethylol melamine, tetramethylol melamine, pentamethylol melamine, hexamethylol melamine, isobutyl ether type melamine, n-butyl ether type melamine and butylated benzoguanamine.

As the inorganic organosol, metals are group II (Mg, Ca, Sr, Ba) and III in the periodic table of the periodic elements.
Group (B, Al, Ga, In, Tl, Sc, Y, La, Ac), Group IV (Si, Ge, Sn, Pb,
Ti, Zr, Hf), V group (As, Sb, Bi, V, Nb, Ta), VI group (Te, Po,
Cr, Mo, W), Group VII (At, Mn, Tc, Re) and Group VIII (Fe, C)
o, Ni, Ru, Rh, Pd, Os, Ir, Pt) metal oxide sol selected from metals and salts of metal oxide sols, siloxanes, metallosiloxanes, silazanes, metallosilazanes, and mixtures thereof The above inorganic organosols are used. A preferred inorganic organosol is a group III (B, Al, Ga, In, Tl, Sc,
Y, La, Ac), Group IV (Si, Ge, Sn, Pb, Ti, Zr, Hf) and Group V (A
s, Sb, Bi, V, Nb, Ta) metal oxide sol, particularly preferably metal oxide sol selected from Si, Al, Sn, Ti and Zn. The metal oxide salt means the metal oxide sol and cations (Li ⁺ , K ⁺ , N
^{a +, Mg 2+, Zn 2+} , Al 3+, salts with Ca ^2+, etc.) or an anion _{^{(S 2-, PO 4 3-,}} SO 4 2-, CH 3 COO, -, NO 3 - ， Cl
^-, F ^- refers to a salt with, etc.).

The proportions of the acrylic polyol resin (A), the binder (B), and the inorganic organosol (C) are, by weight percent, (A) 10 to 80%, (B) 2 to 50%, and (C). It is preferably 5 to 60%, more preferably (A) 30 to 65%, (B) 5 to 30%, and (C) 10 to
40%.

As the solvent, an appropriate amount of a solvent capable of dissolving the above-mentioned respective components can be used. In particular, an organic solvent having a high solubility in the acrylic polyol resin and the inorganic organosol is suitable, for example, xylene, toluene,
Other aromatic hydrocarbon solvents, butyl acetate, other ester solvents, methyl isobutyl ketone, cyclohexanone, other ketone solvents, ethyl cellosolve, other glycol ether solvents, carbitol acetate, other diethylene glycol ester solvents ,
There are various thinners. Of course, the present invention is not limited to these, other hydrocarbon type, halogenated hydrocarbon type,
Alcohol-based, phenol-based, acetal-based, ester-based, ether-based, ketone-based and other solvents can be used. These solvents can be appropriately selected in consideration of the type and state of the article to be coated, the evaporation rate, the working environment, and other conditions, but a ketone solvent is preferable in that a particularly good coating film can be obtained.

The composition of the present invention preferably contains a catalyst for accelerating the reaction from the viewpoint of promoting the curing and improving the workability.

As the reaction accelerating catalyst, a basic or acidic curing catalyst can be used. Examples of the basic catalyst include dibutyltin dilaurate, dibutyltin diacetate, stannas octoate, other organic tin compounds and methylimidazole, acridine, triethylamine,
Hexadecyltrimethylammonium stearate and other amine catalysts are typical compounds. Typical examples of the acidic catalyst are organic sulfonic acids such as methanesulfonic acid, dodecylbenzenesulfonic acid and toluenesulfonic acid. As the catalyst, at least one of these basic catalysts or acidic catalysts is used, but a cocatalyst or the like may be used in combination.

The coating composition of the present invention may optionally further contain other components in addition to the above-mentioned essential and optional catalysts, depending on the purpose. For example, when used as a paint, a pigment can be added as needed.

Examples of pigments include yellow lead, molybdate orange, navy blue, cadmium-based pigments, white titanium, complex oxide pigments, inorganic pigments such as transparent iron oxide, cyclic high-grade pigments, soluble azo pigments, insoluble azo pigments, and copper. Examples of organic pigments include phthalocyanine pigments, dyed pigments, and pigment intermediates.

Further, a colorant, a thixotropic agent, a filler, a thickener, a leveling agent, an antifoaming agent, a stabilizer, and other additives may be added.

The coating composition of the present invention can be produced by mixing the above components by a conventional method.

The coating composition of the present invention is spray coated,
It is coated on a substrate by a known and commonly used method such as brush coating or roll coater, and left to cure at room temperature for about 1 to 10 days, or by baking at 60 to 250 ° C. for 1 to 30 minutes to cure.

The preferred embodiments of the present invention are listed below.

(1) Acrylic polyol resin, one or more binders selected from isocyanate compounds having two or more functional groups, blocked isocyanate compounds and melamine compounds, and the metal is a group II metal ( Mg, Ca, Sr, Ba), Group III metals (B, Al, Ga, In, Tl, S)
c, Y, La, Ac), Group IV metals (Si, Ge, Sn, Pb, Ti, Zr, Hf), V
Group metals (As, Sb, Bi, V, Nb, Ta), Group VI metals (Te, Po, Cr, Mo,
W), Group VII metals (At, Mn, Tc, Re) and Group VIII metals (F
e, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt) selected from metal oxide sols and salts of metal oxide sols, siloxanes, metallosiloxanes, silazanes, metallosilazanes and mixtures thereof. What is claimed is: 1. A coating composition comprising at least one inorganic organosol, and a solvent, and optionally a reaction-promoting catalyst, wherein a hindered phenolic antioxidant is contained in an amount of 0.001 to 3% by weight of solid content and a thioether type. A composition comprising an antioxidant in an amount of 0.001 to 3% by weight based on solid content.

(2) The hindered phenolic antioxidant is a compound having a phenol skeleton, wherein one or both ortho positions of the phenolic hydroxyl group is substituted with a tert-butyl group. Composition.

(3) The composition of (1), wherein the thioether antioxidant is a thioether compound and has two or more long-chain alkyl groups having 6 or more carbon atoms in the molecule.

(4) A hindered phenol-based antioxidant is contained in an amount of 0.03 to 1% by weight based on the solid content, and a thioether-based antioxidant is contained in an amount of 0.03 to 1% by weight based on the solid content (1). )-(3) composition.

EFFECTS OF THE INVENTION The coating composition of the present invention has good weather resistance and also has improved surface hardness as compared with conventional acrylic resin coatings, and therefore also in terms of scratch resistance and antifouling property. It is excellent and can be used in the field of transportation vehicles such as automobiles and train cars. In particular, since it shows remarkable durability against heat deterioration over time, it is suitable for use in parts exposed to high temperatures in summer, such as vehicles, roof parts of building materials, and the like.

[0047]

Examples and Comparative Examples A coating composition was prepared by mixing the following compositions in the compositions shown in Table 1. The blending amount is indicated by parts by weight based on 100 parts by weight of the acrylic polyol resin. About 0.3 mm thick stainless steel plate (SUS 304) after baking the above coating composition
It was applied so as to have a thickness of 20 μm, and treated at a baking temperature of 160 ° C. for 20 minutes to be cured. The physical properties of the obtained coating film were measured, and the results are shown in Table 1.

(1) Acrylic polyol resin Arotan UW2818 (nonvolatile content 60 wt%) (2) Isocyanate coronate 2515 (nonvolatile content 80 wt%) (3) Organosilica sol (4) Solvent cyclohexanone solvent (5) Curing catalyst butyl Tin dilaurate (6) Hindered phenolic antioxidant "Sumilyzer GA-80" manufactured by Sumitomo Chemical Co., Ltd .: in the case of (a) Ciba Geigy Co., Ltd. "Irganox 1010": in the case of (b) in the table "No Guard XL-1" manufactured by Uniroyal Co., Ltd .: In the case of (c) in the table (7) Thioether-based antioxidant "TP-D" manufactured by Sumitomo Chemical Co., Ltd .: In the case of (d) Asahi Denka ( KK "Adeka Stab AO-23": In the case of (e) in the table Test method for coating film physical properties (a) Mitsuzawa: 60 ° reflectance of JIS K 5400 (b) Hardness: JIS K 5400 pencil hardness (C) Bending: Bending Testing machine φ2mm "○" indicates passing "△" indicates almost passing (D) Xylene: Xylene wiping test (E) Weather resistance: Sunshine weatherometer: Accelerated weathering test 3000 hours ○ Initial gloss retention rate 85% (F) Thermal yellowing: Two bake-hardened coated plates are prepared, and one of them is heated in air at 150 ° C for 2 weeks. Two
The color difference between the coating films is measured with a color difference meter and is represented by ΔE. △ E is a Lab color system (JIS Z 8729)
In this case, it can be said that the larger ΔE is, the larger the thermal yellowing is (see below).

This test is an accelerated test simulating the conditions of a roofing material or the like that actually receives heat of 60 to 90 ° C. in the summer.

[0050]

[Table 1]

[0051]

[Table 2]

From Table 1, it can be seen that the coating composition of the present invention containing both the hindered phenol antioxidant and the thioether antioxidant is a coating composition not containing the antioxidant and the antioxidant. It can be seen that the composition exhibits significantly improved thermal yellowing as compared with the coating composition containing either one of the agents.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display area C08G 18/80 NFM

Claims (1)

[Claims] 1. An acrylic polyol resin, at least one binder selected from an isocyanate compound having two or more functional groups, a blocked isocyanate compound and a melamine compound, and the metal is a Group II metal (Mg , Ca, Sr, Ba), Group III metals (B, Al, Ga, In, Tl, Sc, Y, L)
a, Ac), Group IV metals (Si, Ge, Sn, Pb, Ti, Zr, Hf), Group V metals (As, Sb, Bi, V, Nb, Ta), Group VI metals (Te, Po, Cr) , Mo, W),
Group VII metals (At, Mn, Tc, Re) and Group VIII metals (Fe, Co, N)
i, Ru, Rh, Pd, Os, Ir, Pt) and one or more inorganic substances selected from metal oxide sols and salts of metal oxide sols, siloxanes, metallosiloxanes, silazanes, metallosilazanes and mixtures thereof. An organosol, and a coating composition containing a solvent, and optionally a reaction-promoting catalyst, wherein a hindered phenolic antioxidant is added in an amount of 0.001 to 3% by weight of solid content and a thioether antioxidant. A composition containing 0.001 to 3% by weight of solid content.