JP3805721B2 - Paint composition - Google Patents

Description

【００６５】
（実施例１〜５及び比較例１〜３）
前述の有機無機複合樹脂溶液と硬化促進剤を、表２の上段に示す割合で、塗装直前に混合し、各々の塗料組成物を調製した。
【００６６】
得られた塗料組成物につき、以下の通り塗板を作製し、塗膜外観や硬度、耐汚染性、耐熱水性、耐候性、耐アルカリ性及び金属密着性の各塗膜性能試験を行い、その結果をそれぞれ表２の下段に示した。
【００６７】
＜塗板の作製＞
素材として石膏スラグパーライト板（厚さ１２ｍｍ）を用い、その表面にポリイソシアネートプレポリマー溶液シーラー「Ｖセラン♯１００シーラー」（大日本塗料株式会社製商品名）（酢酸ブチル：キシレン＝１：１の溶液で１００％希釈）を塗着量が９０〜１００ｇ／ｍ²（ｗｅｔ質量）となるように吹付塗装した。
【００６８】
これを１００℃で５分間乾燥した。次いで、ベース塗料として、アクリルシリコーン樹脂系塗料「Ｖセラン♯５００エナメル」（大日本塗料株式会社製商品名）（酢酸ブチル：キシレン＝１：１の溶液で４０％希釈）を塗着量が８０〜９０ｇ／ｍ²（ｗｅｔ質量）となるように吹付塗装した。これを１２０℃で１５分間乾燥した。次いで、表２に示す配合からなる塗料組成物を塗着量が１３０±１０ｇ／ｍ²（ｗｅｔ質量）となるように吹付塗装した。これを８０℃で１２分間乾燥した後、室温で更に３日間乾燥し、塗板を作製した。なお、試験方法及び評価は、以下に基づき行った。
【００６９】
但し、金属密着性の評価は、下記に示す通り、表２の塗料組成物をボンデ処理鋼板に、（ｗｅｔ）膜厚１００μｍとなるようにアプリケータで塗装した。乾燥条件は、上記と同様にした。
【００７０】
＜塗膜性能試験＞
塗膜外観：塗板に形成された塗膜外観を目視判定した。
鉛筆硬度：ＪＩＳ Ｋ ５４００（８．４．２）により測定した鉛筆硬度。
耐汚染性：赤、黒マジックインキを塗布してから２４時間後に、ｎ−ブタノールで濡らした布で拭き取り、除染性を目視で下記の様に評価した；
◎・・・完全除去
○・・・極く軽微な汚染
×・・・汚染著しい
耐熱水性：塗板を８０℃の熱水中に１時間・６時間浸漬した後、塗膜外観の異常を目視し、下記の様に評価した；
◎・・・変化なし
○・・・軽微な白化
△・・・光沢低下及び白化
×・・・光沢低下、白化等の変化大
耐候性：サンシャインウェザー−オーメーター３０００時間後の塗膜の光沢を、光沢計で測定し、下記の様に評価した；
○・・・塗膜外観に変化はなく、光沢保持率９５％以上
△・・・塗膜外観変化が軽微にあり、光沢保持率８０〜９４％
×・・・塗膜変化が著しい、光沢保持率８０％未満
耐アルカリ性：飽和消石灰アルカリ水溶液に各塗板を４０℃で１０日間浸漬後、塗膜表面を目視し、下記の様に評価した；
○・・・変化なし
×・・・塗膜表面白濁
金属密着性：ボンデ処理鋼板に、表２に示す塗料組成物を乾燥膜厚１００μｍとなるようにアプリケータで塗装し、８０℃で１２分間乾燥後、室温で更に３日間乾燥し、得られた塗膜について碁盤目テープ法（ＪＩＳ Ｋ５４００ ８．５．２）を実施して、１００個の升目中、塗膜の密着している升目の数を測定した。
【００７１】
【表２】

【００７２】
表２の評価結果から明らかな通り、本発明の塗料組成物である実施例１〜５は、優れた塗膜性能を有していた。
【００７３】
一方、シリル基を含まないウレタン樹脂を使用した比較例１、ウレタン樹脂を過剰に使用した比較例２、オルガノシラン加水分解縮合物を使用しない比較例３は、耐汚染性、耐熱水性、耐候性、耐アルカリ性及び金属密着性が劣っていた。
【００７４】
【発明の効果】
上述したように、本発明によって、基材密着性、耐熱水性、耐候性、耐汚染性及び耐アルカリ性等に優れた塗膜を形成させることのできる塗料組成物を提供することが可能となった。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a coating composition using as a binder an organic-inorganic composite resin capable of forming a coating film excellent in properties such as adhesion, hot water resistance, weather resistance, stain resistance, and alkali resistance.
[0002]
[Prior art]
A coating film using an organic-inorganic composite resin obtained by hydrolytic condensation reaction of organosilane and / or its partially hydrolyzed condensate and a silyl group-containing vinyl resin is excellent in weather resistance, stain resistance, etc. Further, cracks are unlikely to occur as in a coating film using an organopolysiloxane-based inorganic resin as a binder, and therefore, a coating composition using the organic-inorganic composite resin as a binder has been attracting attention.
[0003]
However, adhesion to substrates such as metals and urethane resin plastics is somewhat inferior, and there is room for improvement.
[0004]
[Problems to be solved by the invention]
The object of the present invention is to form a coating film excellent in substrate adhesion, hot water resistance, alkali resistance, weather resistance, stain resistance, etc. by using a specific organic-inorganic composite resin in solving the above problems. It is in providing the coating composition which can be performed.
[0005]
[Means for Solving the Problems]
In accordance with the present invention,
100 parts by mass consisting of organosilane and partial hydrolytic condensates thereof represented by the general formula (I) the following formula (1),
(II) An organic-inorganic composite resin obtained by hydrolytic condensation reaction of 5 to 200 parts by mass of a hydrolyzable silyl group or a urethane resin containing a silyl group having a silicon atom bonded to a hydroxyl group. A coating composition containing a binder and an organic solvent is provided.
[0006]
R ¹ _n Si (OR ² ) _4-n (1)
(Wherein R ¹ is an organic group having 1 to 8 carbon atoms, R ² is an alkyl group having 1 to 5 carbon atoms, and n is 1 or 2)
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
[0008]
Each component of the coating composition of the present invention will be described. First, each component and manufacturing method of organic-inorganic composite resin will be described.
[0009]
<(I) component>
Component (I)
R ¹ _n Si (OR ² ) _4-n (1)
(Wherein R ¹ is an organic group having 1 to 8 carbon atoms, R ² is an alkyl group having 1 to 5 carbon atoms, and n is 1 or 2)
In a partially hydrolyzed condensate of the organosilane及originator indicated.
[0010]
In the above formula (1), examples of the organic group having 1 to 8 carbon atoms as R ¹ include an alkyl group, a cycloalkyl group, an aryl group, and a vinyl group.
[0011]
Here, the alkyl group may be linear or branched. Examples of the alkyl group include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group, t-butyl group, pentyl group, hexyl group, heptyl. And alkyl groups such as an octyl group. Preferably, it has 1 to 4 carbon atoms.
[0012]
Preferred examples of the cycloalkyl group include a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the aryl group include a phenyl group.
[0013]
Each of the above functions may optionally have a substituent. Examples of such a substituent include halogen atoms such as chlorine atom, bromine atom and fluorine atom, (meth) acryloyl group, mercapto group and alicyclic group.
[0014]
The alkyl group as R ² may be linear or branched. Examples of the alkyl group include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group, t-butyl group and pentyl group. The number of carbon atoms is 1 or 2.
[0015]
Specific examples of the organosilane represented by the above formula (1) include, for example, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, and n-propyltriethoxy. Silane, i-propyltrimethoxysilane, i-propyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3,3,3-trifluoro Propyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxysilane, cyclohexyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-mercapto Propyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, Examples thereof include methylphenyldimethoxysilane and dimethyldipropoxysilane, and methyltrimethoxysilane, methyltriethoxysilane and dimethyldimethoxysilane are preferable.
[0016]
These organosilanes can be used singly or in combination of two or more.
[0017]
The component (I) may be the partially hydrolyzed condensate of organosilane described above. The polystyrene-converted weight average molecular weight of the condensate is preferably, for example, 300 to 5000, and more preferably 500 to 3000. By using a condensate having such a molecular weight, storage stability is deteriorated. And a coating film with good adhesion can be obtained. Further, the partially hydrolyzed condensate of organosilane preferably has at least one —OH group or —OR ² group bonded to a silicon atom in the molecule, and more preferably has 3 to 30 groups. .
[0018]
Specific examples of such condensates include commercially available products SH6018, SR2402, DC3037, DC3074 manufactured by Toray Dow Corning; KR-211, KR-212, KR-213, KR-214 manufactured by Shin-Etsu Chemical Co., Ltd. KR-216, KR-218; TSR-145, TSR-160, TSR-165, and YR-3187 manufactured by Toshiba Silicone Corporation.
[0019]
(I) component in the present invention, the n value is one of the organosilane及patron partially hydrolyzed condensate of (I-1), partial hydrolysis of the n value of 2 organosilanes及patron of formula (1) described above The mass ratio (I-1: I-2) to the decomposition condensate (I-2) is preferably (50:50 to 100: 0), more preferably a mixture of (60:40 to 95: 5), When carrying out the hydrolytic condensation reaction, it is desirable since it reacts stably and a coating film with good crack resistance is obtained.
[0020]
<(II) component>
The component (II) has at least one, preferably two or more silyl groups having a hydrolyzable silyl group or a silicon atom bonded to a hydroxyl group at the terminal or side chain of the urethane resin in one molecule of the resin. Is a urethane resin having a weight average molecular weight of, for example, about 1000 to 50000.
[0021]
The silyl group is
-SiX _P (R ³ ) _(3-P) (2)
(In the formula, X is an alkoxy group, a hydrolyzable group such as an acyloxy group, a halogen group or a ketoximate group or a hydroxyl group; R ³ is a monovalent group such as hydrogen or an alkyl group having 1 to 10 carbon atoms, an aryl group or an aralkyl group. And P is an integer of 1 to 3).
[0022]
The alkyl group in the alkoxy group preferably has, for example, 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms, which may be linear or branched. Specific examples of such an alkyl group include, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group, and t-butyl group. And a pentyl group can be preferably exemplified.
[0023]
Preferred examples of the acyloxy group include an acetoxy group and a benzoyloxy group.
[0024]
As a halogen group, a chlorine atom, a bromine atom, a fluorine atom, etc. can be mentioned suitably, for example.
[0025]
Preferred examples of the ketoximate group include an acetoxymate group and a dimethyl ketoximate group.
[0026]
The alkyl group having 1 to 10 carbon atoms as R ³ may be linear or branched. Specific examples of such an alkyl group include, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group, and t-butyl group. And a pentyl group can be preferably exemplified.
[0027]
Preferable examples of the aryl group include a phenyl group.
[0028]
The aralkyl group is a group having a structure in which a hydrogen atom of an alkyl group is substituted with an aryl group, and the ranges of the alkyl group and the aryl group are as described above.
[0029]
The silyl group-containing urethane resin is, for example,
(X) _P (R ³ ) _(3-P) Si—CH ₂ CH ₂ CH ₂ NCO (3)
[Wherein X, R ³ and p are the same as those in the above formula (2)]
Manufactured by using an isocyanato group-containing silane compound having an isocyanate group and a hydrolyzable group represented by the following, simultaneously with polyisocyanate at the time of urethane resin production, or at the time of urethanation reaction with a hydroxyl group-containing compound by a two-stage reaction Is done.
[0030]
Examples of the isocyanato group-containing silane compound include γ-isocyanatopropyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, γ-isocyanatopropylmethyldimethoxysilane, γ-isocyanatopropylmethyldiethoxysilane, Representative examples include γ-isocyanatopropylmethyldipropoxysilane, γ- (meth) acryloxypropyldimethylmethoxysilane, and γ-isocyanatopropyldiethylmethoxysilane.
[0031]
The amount of the isocyanato group-containing silane compound used is suitably 0.5 to 2 moles per mole of urethane resin.
[0032]
The hydroxyl group-containing compound used in the urethanization reaction is a compound having at least two or more hydroxyl groups in one molecule. Specifically, ethylene glycol, 1,2- and 1,3-propanediol, 1,3- And diol compounds such as 1,4-butanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, neopentyl glycol, triethylene glycol, tetraethylene glycol, tripropylene glycol and tetrapropylene glycol; glycerol, trimethylolpropane And polyhydric alcohol compounds such as pentaerythritol, polyester polyols having a hydroxyl value of 50 to 400 mgKOH / g, polycarbonate diols, polyether polyols, acrylic polyols, etc. It can be. The acrylic polyol may have a hydrolyzable silyl group or a silyl group having a silicon atom bonded to a hydroxyl group in the side chain.
[0033]
Next, as the polyisocyanate compound used in the urethanization reaction, linear aliphatic polyisocyanate compounds such as hexamethylene diisocyanate, 1,11-undecane diisocyanate, 1,12-dodecane diisocyanate; isophorone diisocyanate, 2,4- Cyclic polyisocyanate compounds such as diisocyanatotoluene; and known higher functional lacquer polyisocyanate compounds based on hexamethylene diisocyanate and having a maximum molecular weight of 1000 can be used.
[0034]
Typical examples of the catalyst used for the urethanization reaction include triethylamine, tin (II) octoate, dibutyltin oxide, and dibutyltin dilaurate.
[0035]
Next, the manufacturing method of the organic inorganic composite resin used as the binder of this invention is demonstrated.
[0036]
First, in the presence of component (I) and component (II), water, a catalyst, and, if necessary, an organic solvent, they are mixed and stirred to cause a hydrolytic condensation reaction.
[0037]
The mass ratio of the component (I) and the component (II) to be mixed is preferably 4: 6 to 8: 2, and particularly preferably 5: 5 to 6: 4.
[0038]
In addition, when the latter is less than the above range, the appearance, crack resistance, frost damage resistance, alkali resistance, etc. of the obtained coating film are likely to deteriorate, and conversely, when it is excessive, the weather resistance and stain resistance of the obtained coating film are deteriorated. It is not preferable because adhesion to metals and urethane resin-based plastics tends to decrease.
[0039]
The amount of water used for the hydrolysis and condensation reaction is 0.2 to 1. with respect to 1 equivalent of the hydrolyzable group that was initially present in the mixture of the component (I) and the component (II). 0 equivalent is preferred.
[0040]
Examples of the catalyst for the hydrolysis and condensation reaction include inorganic acids such as nitric acid and hydrochloric acid, and organic acids such as acetic acid, formic acid and propionic acid. The amount of the catalyst added is preferably such that the pH of the mixture of (I) and (II) is 3-6. In the hydrolysis condensation reaction, the mixture of the component (I) and the component (II) is preferably 40 to 80 ° C., more preferably 45 to 65 ° C. in the presence of water and a catalyst while stirring for 2 to 10 hours. Although the method of making it react is suitable, it is not limited to this method. The amount of water is 0.2 to 1.0 equivalent of 1 equivalent of the hydrolyzable group that was initially present in the mixture of the components (I) and (II). This is because the storage stability of the film becomes good, and a highly transparent film can be formed when used in a paint. In addition, although it is possible to carry out the hydrolysis condensation reaction of the component (I) and the component (II) in one step as described above, the reaction is performed in the following two steps from the viewpoint of the storage stability of the product. It is preferable to do.
[0041]
That is, in the presence of water and an acid catalyst as the first stage, preferably 40 to 80% by weight, more preferably of hydrolyzable groups that were initially present in the mixture of component (I) and component (II). Is preferably 40 to 80 ° C., more preferably 45 to 65 ° C. for 1 to 8 hours with stirring so that 45 to 70% by mass undergoes a hydrolytic condensation reaction.
[0042]
As the second stage, following the first stage, water and further trialkoxyboranes such as trimethoxyborane and triethoxyborane; tri-n-butoxyethyl acetoacetate zirconium, di-n-butoxydi (ethyl acetoacetate) zirconium, Zirconium chelate compounds such as tetrakis (ethyl acetoacetate) zirconium, titanium chelate compounds such as diisopropoxy bis (acetyl acetate) titanium, diisopropoxy bis (ethyl acetoacetate) titanium, monoacetyl acetate bis (ethyl acetoacetate) aluminum, An organometallic compound catalyst such as an aluminum chelate compound such as diisopropoxyethyl acetoacetate aluminum is added to cause hydrolysis and condensation reaction.
[0043]
The amount of water added in the second stage is preferably 45 to 100% by mass, more preferably 50 to 90% by weight of the hydrolyzable group that was initially present in the mixture of component (I) and component (II). % By mass is sufficient for hydrolysis and condensation reactions.
[0044]
The trialkoxyborane and the organometallic compound catalyst used in the second stage can accelerate the condensation reaction and improve the appearance of the coating film, weather resistance, stain resistance, hot water resistance, and the like. The amount of these catalysts is 0.001 to 5 parts by mass with respect to 100 parts by mass of the total amount of the component (I) and the component (II) remaining unreacted with the reaction product obtained in the first stage. 0.005 to 2 parts by mass is more preferable. The hydrolysis condensation reaction in the second stage is suitably performed at 40 to 80 ° C. for 2 to 5 hours as in the first stage.
[0045]
An organic solvent is used for dilution for adjusting the solid content of the composition of the present invention and at the same time for improving the coating workability and the like. Specific examples thereof include alcohols such as methanol, ethanol, propanol and butanol, alcohol ethers such as ethylene glycol monoethyl ether and ethylene glycol monobutyl ether, hydrophilic organic solvents such as ketones such as acetone and methyl ethyl ketone, toluene, Examples thereof include mixed organic solvents with various hydrophobic organic solvents for paints such as xylene, ethyl acetate and butyl acetate. Although the compounding quantity of the organic solvent is adjusted according to the intended purpose, 20-90 mass% is preferable in a coating composition, More preferably, it is 40-80 mass%.
[0046]
The coating composition of the present invention comprises the above-described organic-inorganic composite resin, organic solvent, and, if necessary, a filler and a dye for improving the storage stability and coating workability of the coating composition, and further curing acceleration. Composed of various additives such as an agent, a thickener, a pigment dispersant, a light stabilizer and an ultraviolet absorber.
[0047]
As the filler, various extender pigments and coloring pigments such as talc, barium carbonate, calcium carbonate, barium carbonate, bentonite, titanium oxide, carbon black, Bengala, and lithopone can be used. The blending amount of the filler is preferably 0 to 70 parts by mass, particularly preferably 0 to 50 parts by mass with respect to 100 parts by mass of the solid content of the coating composition.
[0048]
Examples of the curing accelerator include organic tin compounds such as tin octylate, dibutyltin dilaurate, dibutyltin dimaleate and tributyltin laurate, amine compounds such as ethylenediamine, diethylenetriamine, piperidine, phenylenediamine and triethylamine, sodium hydroxide, sodium carbonate, carbonic acid Representative examples include inorganic acid salts such as potassium, sodium hydrogen carbonate, and magnesium sulfate; organic acid salts such as lithium formate and magnesium acetate, and organic tin compounds are particularly effective.
[0049]
The coating composition of the present invention can form a cured coating film by coating the surface of an object to be coated with a coating means such as brush, spray, roll and dipping, and baking at room temperature or a temperature of 300 ° C. or lower. is there. In addition, as a to-be-coated object, it can use for various to-be-coated objects, such as inorganic ceramic industry base materials, various metal base materials, such as stainless steel and aluminum, a glass base material, a plastic base material, and a paper base material.
[0050]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. In the examples, “parts” and “%” are based on mass unless otherwise specified.
[0051]
<Preparation of polyester polyol solution (I)>
Into a 3 liter reactor equipped with a stirrer, a cooler, a heater, and a water separator, 564 parts of 1,6-hexanediol, 80 parts of neopentyl glycol, and 584 parts of adipic acid were added, and the temperature was 220 ° C. in a nitrogen stream. Slowly heated. The overhead temperature did not exceed 102 ° C. Condensation was continued while removing the produced water, and when the acid value reached 15 mgKOH / g, the mixture was cooled and diluted with methyl ethyl ketone to a non-volatile content of 70% to prepare a polyester polyol solution (I).
[0052]
The prepared polyester polyol (a) had a hydroxyl value of 175 mgKOH / g and a number average molecular weight of 590.
[0053]
<Preparation of polyester polyol solution (b)>
Into a 3 liter reactor equipped with a stirrer, a cooler, a heater and a water separator, 640 parts of 1,6-hexanediol, 25 parts of neopentyl glycol, and 594 parts of adipic acid were added, and the temperature was 220 ° C. in a nitrogen stream. Slowly heated. The overhead temperature did not exceed 102 ° C. Condensation was continued while removing the produced water, and when the acid value reached 10 mgKOH / g, the mixture was cooled and diluted with methyl ethyl ketone to a non-volatile content of 70% to prepare a polyester polyol solution (B).
[0054]
The prepared polyester polyol (b) had a hydroxyl value of 170 mgKOH / g and a number average molecular weight of 620.
[0055]
<Preparation of organic-inorganic composite resin solution A>
(1) In a reactor equipped with a stirrer, a reflux condenser and a heater, 267 parts of the above polyester polyol solution (ii), 57 parts of isophorone diisocyanate, 6 parts of γ-isocyanatopropyltrimethoxysilane, 0.06 of dibutyltin dilaurate After stirring for 1 hour at 75 ° C. with stirring, the mixture was cooled to room temperature to obtain a silyl group-containing polyurethane solution having a nonvolatile content of 76%. This polyurethane had an acid value of 11 mgKOH / g and a weight average molecular weight of 28,400.
[0056]
(2) In a reactor equipped with a stirrer, a reflux condenser and a heater, 330 parts of the silyl group-containing polyurethane solution prepared in (1) and a partial hydrolysis condensate of methyltrimethoxysilane (Toray Dow Corning Co., Ltd.) SR2402 (100% solids), 90 parts of methyltrimethoxysilane, 20 parts of dimethyldimethoxysilane, and 100 parts of isopropanol were added and mixed by stirring, followed by 30 parts of ion-exchanged water and 1N hydrochloric acid. 0.5 part was added and it was made to react at 60 degreeC for 3 hours. Next, 3 parts of monoacetylacetonate bis (ethylacetoacetate) aluminum and 8 parts of ion-exchanged water were added, and the mixture was further reacted at 60 ° C. for 3 hours. Next, 317 parts of isopropanol as a diluent solvent was added and stirred to obtain an organic-inorganic composite resin solution A having a solid concentration of 45%.
[0057]
<Preparation of organic-inorganic composite resin solution B>
(1) In a reactor equipped with a stirrer, a reflux condenser and a heater, 267 parts of the above polyester polyol solution (b), 57 parts of isophorone diisocyanate, 6 parts of γ-isocyanatopropyltrimethoxysilane, 0.06 of dibutyltin dilaurate After stirring for 1 hour at 75 ° C. with stirring, the mixture was cooled to room temperature to obtain a silyl group-containing polyurethane solution having a nonvolatile content of 76%. This polyurethane had an acid value of 8 mgKOH / g and a weight average molecular weight of 29,400.
[0058]
(2) According to the composition of Table 1, an organic-inorganic composite resin solution B was obtained in the same manner as in the preparation (2) of the organic-inorganic composite resin solution A described above.
[0059]
In the same manner, organic-inorganic composite resin solutions C 1 , D, and F were prepared under the same reaction conditions as those of organic-inorganic composite resin solution A according to the formulation in Table 1.
[0060]
<Preparation of organic-inorganic composite resin solution G>
An organic-inorganic composite resin solution G was obtained in the same manner as the organic-inorganic composite resin solution A except that in the preparation of the organic-inorganic composite resin solution A, all γ-isocyanatopropyltrimethoxysilane was replaced with isophorone diisocyanate. .
[0061]
<Preparation of organic-inorganic composite resin solution H>
According to the composition of Table 1, an organic-inorganic composite resin solution H was prepared under the same reaction conditions as the organic-inorganic composite resin solution A.
[0062]
<Preparation of organic-inorganic composite resin solution I>
To a reactor equipped with a stirrer, a reflux condenser and a heater, 267 parts of a polyester polyol solution (ii), 57 parts of isophorone diisocyanate, 6 parts of γ-isocyanatopropyltrimethoxysilane, and 0.06 part of dibutyltin dilaurate are added and stirred. However, after reacting at 75 ° C. for 1 hour, the mixture was cooled to room temperature to obtain a silyl group-containing polyester polyurethane solution having an acid value of 11 mgKOH / g, a weight average molecular weight of 28,400, and a nonvolatile content of 76%.
[0063]
To this, 225 parts of isopropanol as a diluent solvent was added and stirred to obtain an organic-inorganic composite resin solution I having a solid concentration of 45%.
[0064]
[Table 1]

[0065]
(Examples 1-5 and Comparative Examples 1-3)
The aforementioned organic-inorganic composite resin solution and the curing accelerator were mixed at the ratio shown in the upper part of Table 2 immediately before coating to prepare each coating composition.
[0066]
About the obtained coating composition, a coated plate was prepared as follows, and each coating film performance test of coating film appearance, hardness, stain resistance, hot water resistance, weather resistance, alkali resistance and metal adhesion was performed, and the result was Each is shown in the lower part of Table 2.
[0067]
<Preparation of coated plate>
A gypsum slag perlite plate (thickness 12 mm) is used as a material, and a polyisocyanate prepolymer solution sealer “V-Selan # 100 sealer” (trade name, manufactured by Dainippon Paint Co., Ltd.) (butyl acetate: xylene = 1: 1) The solution was spray-coated so that the coating amount was 90 to 100 g / m ² (wet mass).
[0068]
This was dried at 100 ° C. for 5 minutes. Next, as the base paint, an acrylic silicone resin paint “V-Selan # 500 Enamel” (trade name, manufactured by Dainippon Paint Co., Ltd.) (diluted 40% with a solution of butyl acetate: xylene = 1: 1) was applied in an amount of 80 It spray-coated so that it might become -90g / m < ² > (wet mass). This was dried at 120 ° C. for 15 minutes. Subsequently, the coating composition which consists of a mixing | blending shown in Table 2 was spray-coated so that the coating amount might be 130 +/- 10g / m < ² > (wet mass). This was dried at 80 ° C. for 12 minutes, and further dried at room temperature for 3 days to prepare a coated plate. In addition, the test method and evaluation were performed based on the following.
[0069]
However, as shown below, the metal adhesion was evaluated by applying the coating composition shown in Table 2 on a bond-treated steel sheet with an applicator so that the (wet) film thickness was 100 μm. The drying conditions were the same as described above.
[0070]
<Film performance test>
Coating film appearance: The coating film appearance formed on the coated plate was visually determined.
Pencil hardness: Pencil hardness measured according to JIS K 5400 (8.4.2).
Contamination resistance: 24 hours after application of red and black magic ink, wiped off with a cloth wetted with n-butanol, and decontamination was visually evaluated as follows:
◎ ... Complete removal ○ ... Extremely slight contamination ×… Contaminated hot water resistance: After immersing the coated plate in hot water at 80 ° C for 1 hour or 6 hours, visually check the appearance of the coating film Evaluated as follows:
◎ ・ ・ ・ No change ○ ・ ・ ・ Slight whitening △ ・ ・ ・ Gloss reduction and whitening × ・ ・ ・ Changes such as gloss reduction, whitening, etc. Large weather resistance: Sunshine weather-Gloss of coating after 3000 hours Measured with gloss meter and evaluated as follows:
○: No change in appearance of coating film, gloss retention of 95% or more Δ: Minor change in coating film appearance, gloss retention of 80-94%
X: Significant change in coating film, gloss retention of less than 80% Alkali resistance: Each coated plate was immersed in a saturated slaked lime alkaline aqueous solution at 40 ° C. for 10 days, and the coating film surface was visually observed and evaluated as follows:
○ ... No change x ... Coating surface white metal adhesion: The paint composition shown in Table 2 was applied to a bonde-treated steel sheet with an applicator so as to have a dry film thickness of 100 μm, and then at 80 ° C. for 12 minutes. After drying, the film is further dried at room temperature for 3 days, and the obtained coating film is subjected to a cross-cut tape method (JIS K5400 8.5.2), and 100 of the cells are in close contact with the coating. Number was measured.
[0071]
[Table 2]

[0072]
As is clear from the evaluation results in Table 2, Examples 1 to 5, which are the coating compositions of the present invention, had excellent coating performance.
[0073]
On the other hand, Comparative Example 1 using a urethane resin not containing a silyl group, Comparative Example 2 using an excessive amount of urethane resin, and Comparative Example 3 not using an organosilane hydrolysis condensate are stain resistance, hot water resistance, and weather resistance. The alkali resistance and metal adhesion were inferior.
[0074]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a coating composition that can form a coating film excellent in substrate adhesion, hot water resistance, weather resistance, stain resistance, alkali resistance, and the like. .

Claims (3)

(I) 100 parts by mass consisting of an organosilane represented by formula (1) and a partial hydrolysis-condensation product thereof;
R ¹ _n Si (OR ² ) _4-n (1)
(Wherein R ¹ is an organic group having 1 to 8 carbon atoms, R ² is an alkyl group having 1 to 5 carbon atoms, and n is 1 or 2)
(II) A binder composed of an organic-inorganic composite resin obtained by hydrolytic condensation reaction with 5 to 200 parts by mass of a hydrolyzable silyl group or a urethane resin containing a silyl group having a silicon atom bonded to a hydroxyl group, and an organic A coating composition comprising a solvent.   The coating composition of Claim 1 which has as a main component organic-inorganic composite resin whose mass ratio of component (I) and component (II) shown above is 4: 6-8: 2. The hydrolytic condensation reaction of component (I) and component (II) shown above is from the first stage reaction using water and an acid catalyst and the second stage reaction using water and an organometallic compound catalyst. The coating composition according to claim 1 or 2.