KR0167706B1 - Paint compositions - Google Patents

Abstract

The present invention relates to a coating composition based on a silicone-modified polyester resin and an epoxy group-containing acrylic resin, wherein 5 to 85% by weight of aliphatic glycol having three or more reactors and less than 20% by weight of aliphatic glycol having two reactors is reactive. Silicon modified by preparing an intermediate resin by mixing and reacting 1 to 30% by weight of a silicon compound and 1 to 3% by weight of a titanium catalyst, and adding an acid anhydride such that the molar ratio of acid to its residual glycol content is 0.8 to 1. Polyester resin; Epoxy group-containing acrylic resin having an epoxy group equivalent of 150 to 1000, wherein the acid composition of the silicone-modified polyester resin and the epoxy group equivalent ratio in the acrylic resin are 1: 0.5 to 0.5: 1, and the coating composition is particularly excellent in acid resistance compared to conventional paints. There is an advantage.

Description

Paint composition based on silicone-modified polyester resin and epoxy-containing acrylic resin

The present invention can be used as general industrial and PCM (PCM) paints, and in particular, it is excellent in acid resistance, fouling resistance and weather resistance, and is a coating composition suitable for automotive top coatings based on thermosetting silicone-modified polyester resins and epoxy-containing acrylic resins. It relates to a paint composition.

Conventional paints for automotive top coats are acrylic or polyester paints, and in particular, acrylic melamine resins and polyester melamine resin type thermosetting solvent paints have been used.

However, such thermosetting solvent-based paints have significant problems such as acid resistance weakness and poor durability, such as corrosion against acid rain and corrosion of paint due to acidic environment in the industrial area, which are now a serious problem in the world.

Therefore, as a countermeasure, a 2-pack type using polyols such as acrylic polyols or polyester polyols and a polyisocyanate curing agent instead of melamine resins that weaken acid resistance, and a 1-pack type automotive clear and industrial coatings using blocky isocyanate curing agents Is the trend being used.

However, such paints have some improvements in acid resistance, gloss and durability, but the polyisocyanate reacts strongly with moisture, requiring modification of existing coating line equipment, and toxic and poor workability and poor weatherability. In addition, the coating film has a problem of yellowing.

Most of these coatings for automotive topcoats are manufactured as a technique for synthesizing low molecular weight polyester for improving weather resistance and then reacting with a hydroxyl group at the end or simultaneously with a raw material used for polyester production. As disclosed in Patent Publications Nos. 56-157462 and 56-567481, US Pat. Nos. 4, 289, 677 and German Patent Nos. 2, 949, 725.

This is used for a kind of methoxy or butoxy type amino formaldehyde hybrid paint such as aminoplasts by inducing hydroxyl groups at the end of the final resin, and has a characteristic of improving weather resistance. The ether bonds induced after this curing did not completely solve the problem of acid resistance.

An object of the present invention is to solve the problems of the conventional automotive coating paints as described above, while solving the problems of the polyisocyanate curing agent has a good film stiffness and acid resistance, excellent silicone weathering, acid resistance and other physical properties modified silicone resin And a coating composition based on an epoxy-containing acrylic resin.

The silicone-modified polyester resin and the epoxy-containing paint composition of the present invention for achieving the above object is 5 to 85% by weight of aliphatic glycol having three or more reactors, less than 20% by weight of aliphatic glycol having two reactors, Or 1 to 30% by weight of a reactive silicone compound represented by 2 and 1 to 3% by weight of a titanium catalyst to prepare an intermediate resin, and an acid anhydride is added so that the molar ratio of acid to its residual glycol content is 0.8 to 1. Silicone-modified polyester resin prepared by addition; And an epoxy group-containing acrylic resin having an epoxy group equivalent of 150 to 1000, such that the acid group of the silicone-modified polyester resin and the epoxy group equivalent ratio in the acrylic resin are 1: 0.5 to 0.5: 1.

In the above formula, R ₁ is an alkyl group having 1 to 12 carbon atoms or an aryl group, and R is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

In the above formula, R ₃ is an alkyl or aryl group having 1 to 6 carbon atoms, and R ₄ is a methoxy group or an ethoxy group.

The present invention will be described in more detail as follows.

In the present invention, the paint composition reacts a reactive silicone compound with one or more glycols having a bifunctional or higher functionality to produce a polyfunctional polyol in which a silicone compound is modified in the resin skeleton, and then ring-opens the reaction with an acid anhydride to form a polyester resin. It is characterized by using a thermosetting silicone-modified polyester resin having a carboxyl group at the terminal of the modified polyfunctional resin which is a silicone compound.

That is, by inducing the characteristics of the silicone compound excellent in weather resistance, chemical resistance and heat resistance and imparting it in the resin skeleton, it solves the problem of acid resistance of the cured coating film, which is a conventional problem, and has excellent durability, excellent screening properties, It is made to have a carboxyl group in the terminal of resin which has scratch resistance and acid resistance.

Here, look at the method of manufacturing the silicone-modified polyester resin in detail.

First, trimethylol propane, triethylol propane, di-trimethylol propane, glycerin 5 to 85% by weight as aliphatic glycols having three or more reactors, neopentyl glycol, hydroxy pivalyl hydroxy as aliphatic glycols having two reactors An intermediate resin was prepared using less than 20% by weight of pipalate (Eastman, trade name: HPHP), 1-30% by weight of a reactive silicone compound, and 1-2% by weight of a titanium-based catalyst, and the intermediate resin contained a large amount of residual hydroxyl groups. Add raw materials with reactable acid anhydrides. At this time, the acid anhydride has an acid molar ratio of 1.0 or less, preferably 0.8 to 1.0, an acid value of 400 mg KOH / g or less, an equivalent of carboxylic acid of 700 or less, and a number average molecular weight relative to the residual glycol equivalent. 500-3000, preferably 800-2000 (wherein the number average molecular weight is determined by gel permeation chromatography using polystyrene as a standard, the molecular weight obtained in this way is not the actual molecular weight but the molecular weight compared to polystyrene) ) Anhydride is slowly added to the intermediate resin at 1 to 4 hours at the reaction temperature of 100 ~ 120 ℃. And after adding all the anhydrides, it keeps for 2 to 4 hours, and dilutes and cools. The semi-ester product is then ring-opened to produce a silicone-modified polyester resin in which the polyvalent carboxyl group remains at the resin end.

The raw material component used for manufacture of a silicone modified polyester resin is demonstrated.

Glycols are aliphatic and cycloaliphatic glycols having 2 to 20 carbon atoms that are bifunctional or higher. Specific examples include ethylene glycol, 1, 2-propane diol, neopentyl glycol, diethylene glycol, 1, 4-butanediol, and trimethylol propane. , Pentaerythritol, dipenta, erythritol, ditrimethylol propane, hydroxy pivalyl hydroxy pivalate (Eastman, trade name HPHP), aliphatic polyols or aromatic polyols can be used.

In order to manufacture a polyester resin having a polyvalent carboxyl group remaining at the end of the resin, it is reacted under appropriate reaction conditions using a 1,2-dicarboxylic acid anhydride capable of reacting with glycol to ring-open the ring of anhydride and the carboxyl group at the end of the resin. It must remain.

Acid anhydrides that can be used here include cyclic and aromatic phthalic anhydrides having 4 to 12 carbon atoms, succinic anhydrides, methyl succinic anhydrides, octadecanyl succinic anhydrides, and tetrahydro phthalic anhydrides. Hydrides, octadecanyl succinic unhydrides, tetrahydro phthalic unhydrides, methyl tetra phthalic unhydrides, hexahydro phthalic unhydrides, alkyl hexahydro phthalic unhydrides, itaconic unhydrides, Citaconic anhydride, crorendic anhydride and the like.

Reactive silicone compounds have unique properties such as high heat resistance, weather resistance and low surface tension, which are not found in other polymers. The molecular skeleton of silicon consists of Si-O.

Such silicon compound is inherently different from general synthetic polymer made of CC skeleton, and Si-O bond is close to ionic bond because it has a large difference in electronegativity of Si- and -O. Excellent flexibility at low temperatures, low surface tension, high water repellency, strong weather resistance, inert, high electrical insulation, insoluble, insoluble in oil, and has good compressibility.

In particular, the reactive silicone compound used in the present invention is preferably a compound represented by the formula (1) or (2).

The reaction between the glycol and the reactive silicone compound is shown in Chemical Formula 1.

The content of the reactive silicone compound is 1 to 30% by weight, more preferably 5 to 15% by weight. If the content of the reactive silicone compound in the polyester resin is more than 30% by weight, the site of the acid-curing reaction with the epoxy-containing acrylic resin is too small, the hardness is lowered, and also the water resistance, weather resistance and resistance to chemicals is lowered.

Catalysts used to promote the reaction between the reactive silicone compound and glycol are titanium-based compounds, such as titanium alkoxides, titanium chelate compounds, or aluminum chelate-based catalysts, and tetraisopropyl titanate, tetrabutyl titanate, and the like. It is more preferable to use.

In the use of a catalyst, when a triphenyl phosphate, tributyl borate or octate catalyst other than the titanium catalyst is used, a silicone compound cannot be denatured to the polyester resin skeleton and a problem occurs that the silicon compounds react. Careful selection must be made.

Solvents used in the production of silicone-modified polyester resins are those which impart viscosity, ease of handling of resins, and stability in paint workability, appearance, and curing reaction, and are normally propyl alcohol, isopropyl alcohol, normal butanol, and isobutanol. Alcohols having 3 to 6 carbon atoms such as methyl isobutyl carbinol and cyclohexanol; Glycol esters such as methyl glycol acetate, ethylene glycol acetate, butyl glycol acetate, ethyl diglycol acetate, butyl diglycol acetate and the like; Hydroxy ethers such as methyl glycol, ethyl glycol, isopropyl glycol, butyl glycol, isobutyl glycol, methyl diglycol, ethyl diglycol, butyl diglycol and the like; Ketones such as methyl isobutyl ketone, diisobutyl ketone, ethyl butyl ketone, cyclohexanone and the like; And aromatic systems such as xylene, toluene and the like can be used by mixing one or two or more thereof.

On the other hand, in the coating composition of the present invention, the epoxy group-containing acrylic resin blended with the silicone-modified polyester resin is obtained through the following method.

The epoxy group-containing acrylic resin, that is, the acrylic copolymer resin having an epoxy group is an epoxy group such as glycidyl methacrylate, glycidyl acrylate, methyl glycidyl methacrylate, methyl glycidyl acrylate or aryl glycidyl ether. Using one or more monomers having a must be adjusted to the amount of epoxy equivalent 150 ~ 1000.

If the epoxy equivalent is more than 1000, the curability of the paint is insufficient, and the pencil hardness and solvent resistance are poor, and if the epoxy equivalent is less than 150, the appearance of the coating is poor.

In addition, monomers include methyl methacrylate, methyl acrylate, ethyl methacrylate, ethyl acrylate, propyl methacrylate, propyl acrylate, n-butyl methacrylate, n-butyl acrylate, isobutyl methacrylate, Isobutyl acrylate, t-butyl methacrylate, t-butyl acrylate, 2-ethylhexyl methacrylate, 2-ethylhexyl acrylate, stearyl methacrylate, stearyl acrylate, cyclohexyl methacrylate, Cyclohexyl acrylate, benzyl methacrylate, benzyl acrylate, hydroxy ethyl methacrylate, hydroxy ethyl acrylate, hydroxy propyl methacrylate, hydroxy propyl acrylate, methyl methacrylate, acrylic acid, styrene monomer, Butyl acrylate, ethyl hexyl acrylate, etc. It can be used as a solution polymerization method of the phase, and as the polymerization initiator, peroxides such as benzyl peroxide, di-t-butyl peroxide, di-cumyl peroxide, cumene hydroperoxide, t-amyl peroxide and azo initiators Bar, the content thereof is preferably 2 to 15% by weight based on the total weight of the acrylic monomer. In addition, 2-mercapto ethanol, benzene thioethanol, butyl mercaptan and the like may be used within 10% by weight of the total weight as a chain stopper for controlling the molecular weight of the acrylic resin.

Solvents that can be used in the production of epoxy-containing acrylic resins include methyl amyl ketone, xylene, toluene, helpless PMA, etapro EEP, cellosolbu acetate, cocosol 100, cocosol 150 and the like.

On the other hand, the paint composition of the present invention is the epoxy group equivalent of (b) to the acid value of (a) from the silicone-modified polyester resin (a) and the epoxy-containing acrylic resin (b) as described above is 1: 0.5 to 0.5: 1 If necessary, melamine is used as a modifier for the addition of metal salts, amines and Lewis acids as catalysts and small amounts of external appearance regulators, UV absorbers, hardness enhancement, and other physical properties of the final paint, for the purpose of controlling the baking temperature during curing. It is prepared by adding a resin and a resin having an amino group, and mixing a small amount of the aromatic and aliphatic hydrocarbon solvents to adjust the viscosity. In this case, melamine resin is used in 20 weight% or less with respect to the whole paint.

Such paints can be used on basecoats made of acrylic melamine resins, polyester melamine-based metal pigments and colorants which are commonly applied to automotive paints for crees, and conventional basecoats (metallic or solid colors) can be used. After 1-10 minutes at room temperature, apply a cree coat by wet-on-wet method and leave it for 5-20 minutes, then apply the coated object at 80 ~ 180 ℃. Drying for 60 minutes completes the desired painting.

Hereinafter, the present invention will be described in detail through examples. These examples show preferred embodiments of silicone modified polyester resins, epoxy-containing acrylic resins, and automotive topcoat compositions containing these two materials, and are not intended to limit the scope of the invention.

[Production Example 1]

250 g of ditrimethylol propane, 0.15 g of tetra isopropyl titanate, 26 g of DC-3037 (manufactured by Dow Corning, Inc.) and 300 g of EEP were added to a reaction tank, heated to 140 ° C. under a nitrogen atmosphere, and held for 2 hours. Cool to 110 ° C. and add 650 g of methyl hexahydro phthalic anhydride dropwise over 2 hours.

And it heated up to 120 degreeC, confirmed by IR, it reacted until anhydride was removed, and cooled.

After the reaction was completed, 190 g of eta pro EEP solvent (manufactured by Eastman Co., Ltd.) was added thereto, and the mixture was diluted. The mixture was cooled to room temperature to obtain a resin (PE-1) having a solid content of 65.5%, an acid value of 230, and a number average molecular weight of 1800.

[Production Example 2]

250 g of ditrimethylol propane, 0.15 g of tetra isopropyl titanate, 30 g of Z6018 (manufactured by Dow Corning Co., Ltd.), and 300 g of EEP were placed in a reaction tank and heated to 140 ° C. under a nitrogen atmosphere.

The temperature was then cooled to 110 ° C. and 640 g of methyl hexahydro phthalic anhydride was added dropwise over 4 hours.

Then, it heated up to 120 degreeC, confirmed by IR, it reacted until anhydride was removed, and cooled.

After completion of the reaction, 200 g of the eta pro EEP solvent was added and diluted, followed by cooling to room temperature to obtain a resin (PE-2) having a solid content of 65.2%, an acid value of 210 and a number average molecular weight of 2540.

[Manufacture example 3]

After adding 520 g of xylene to a clean reaction tank, the mixture was gradually heated to reflux, and in a separate acrylic synthesis monomer tank, 296.4 g of glycidyl methacrylate, 195 g of butyl acrylate, and 140.4 g of normal-butyl methacrylate. , 117 g of methyl methacrylate, 31.2 g of styrene monomer, and 46.8 g of t-butyl peroxy benzoate were added thereto, mixed uniformly, and reacted dropwise into the reactor uniformly over 3 hours.

Then, the reaction was carried out for 4 hours and then cooled to room temperature to obtain a resin (EP-1) having a solid content of 59.8%, an epoxy equivalent of 374, a glass transition temperature of 14.7 ° C, and a number average molecular weight of 1350.

[Production Example 4]

327.6 g glycidyl methacrylate, 78.0 g butyl acrylate, 156.0 g normal-butyl methacrylate, 156.0 g methyl methacrylate, 62.4 g styrene monomer and 54.5 g t-butyl peroxy benzoate A resin (EP-2) having a solids content of 60.4%, an epoxy equivalent of 338, a glass transition temperature of 37.3 ° C., and a number average molecular weight of 1150 was prepared under the same conditions and methods as in Preparation Example 3, except that the reaction mixture was added dropwise to the reaction vessel containing xylene. It was.

Production Example 5

273.0 g glycidyl methacrylate, 78.0 g butyl acrylate, 156.0 g normal-butyl methacrylate, 156.0 g methyl methacrylate, 117 g 2-ethylhexyl acrylate, 40.5 g t-butyl peroxy benzoate Resin with a solid content of 60.1%, an epoxy equivalent of 406, a glass transition temperature of 6.41 ° C., and a number average molecular weight of 1590, under the same conditions and methods as in Preparation Example 3, except that the mixture was mixed dropwise and reacted in a reaction tank containing xylene in a dropwise manner (EP-3 ) Was prepared.

EXAMPLES 1-4

Next, the raw material was mixed with the composition as shown in Table 1 to prepare a coating for automotive topcoat, and the results of the physical property test were shown in Table 2 below.

As a comparative example of the paint composition according to the present invention, an acrylic + melamine type paint (commercially available) was purchased and used.

As described in detail above, according to the present invention, an intermediate resin is prepared by mixing and reacting an aliphatic glycol having three or more reactors, an aliphatic glycol having two reactors, a reactive silicone compound 1-30 wt%, and a titanium catalyst. Silicone modified polyester resin manufactured by adding an acid anhydride here; The paint composition obtained by blending an epoxy group-containing acrylic resin in a constant equivalent ratio is particularly excellent in acid resistance compared to conventional paints and is suitable for automotive top coats.

Claims (6)

5 to 85% by weight of fatty acid glycol having three or more reactors, 0 to 20% by weight of aliphatic glycol having two reactors, 1 to 30% by weight of a reactive silicone compound represented by the following Chemical Formula 1 or 2 and 1 to 3 titanium catalyst A silicone-modified polyester resin prepared by adding an acid anhydride such that the weight ratio is mixed to prepare an intermediate resin, and an acid molar ratio of the acid to its residual glycol content is 0.8 to 1; And a silicone-modified polyester resin and an epoxy-containing acrylic, wherein an epoxy group-containing acrylic resin having an epoxy group equivalent of 150 to 1000 is blended with the silicone-modified polyester resin such that an acid group and an epoxy group in the acrylic resin have an equivalent ratio of 1: 0.5 to 0.5: 1 equivalent ratio. Resin-based paint composition. In the above formula, R ₁ is an alkyl group having 1 to 12 carbon atoms or an aryl group, and R is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. In the above formula, R ₃ is an alkyl or aryl group having 1 to 6 carbon atoms, and R ₄ is a methoxy group or an ethoxy group. The method of claim 1, wherein the acid anhydride includes cyclic and aromatic phthalic anhydrides having 4 to 12 carbon atoms, succinic anhydride, methyl succinic anhydride, octadecanyl succinic anhydride, and tetrahydroprop. Thalic unhydride, octadecanyl succinic anhydride, tetrahydro phthalic unhydride, methyl tetra phthalic unhydride, hexahydro phthalic unhydride, alkyl hexahydro phthalic unhydride, hexahydroprop Silicone modified poly, characterized in that one or more selected from the group consisting of talc unhydride, alkyl hexahydro phthalic unhydride, itaconic unhydride, citaconic unhydride, and crorendic unhydride Coating composition based on ester resin and epoxy-containing acrylic resin. The method of claim 1, wherein the titanium-based catalyst is at least one selected from the group consisting of tetra isopropyl titanate, tetrabutyl titanate, titanium chelate compound, aluminum chelate compound and silicone-modified polyester resin containing epoxy Paint composition based on acrylic resin. According to claim 1, wherein the epoxy group-containing acrylic resin is an epoxy group consisting of glycidyl methacrylate, glycidyl acrylate, methyl glycidyl methacrylate, methyl glycidyl acrylate, arylglycidyl ether Branches have at least one acrylic monomer, methyl methacrylate, methyl acrylate, ethyl methacrylate, methyl acrylate, propyl methacrylate, propyl acrylate, n-butyl methacrylate, n-butyl acrylate, isobutyl meta Acrylate, isobutyl acrylate, t-butyl methacrylate, t-butyl acrylate, 2-ethyl hexyl methacrylate, 2-ethyl hexyl acrylate, stearin methacrylate, stearin acrylate, cyclohexyl methacrylate Cyclohexyl acrylate, benzyl methacrylate, benzyl acrylate, hydroxy ethyl With methacrylate, hydroxy ethyl acrylate, hydroxy propyl methacrylate, hydroxy ethyl acrylate, hydroxy propyl methacrylate, hydroxy propyl acrylate, methyl methacrylate, acrylic acid, styrene monomer, butyl acrylate A coating composition based on a silicone-modified polyester resin and an epoxy-containing acrylic resin, characterized in that one or more acrylic monomers containing no epoxy composition are mixed to produce a solution polymerization method in the presence of a polymerization initiator and a chainporter. The method of claim 4, wherein the polymerization initiator is selected from benzyl peroxide, di-t-butyl peroxide, di-cumyl peroxide, cumene hydroperoxide, t-amyl peroxide, and azoge initiator. A coating composition based on a silicone-modified polyester resin and an epoxy-containing acrylic resin, characterized by being at least one species. The coating composition according to claim 4, wherein the chain stopper is at least one selected from 2-mercapto ethanol, benzenethioethanol, and butyl mercaptan.