KR100193393B1 - Coating composition containing thermosetting modified polyester resin - Google Patents

Abstract

The present invention relates to a method for producing a thermosetting modified polyester resin for paints and to a coating composition containing the same, and more specifically, to at least one alkylene glycol component having 2 to 20 carbon atoms and at least 6 to 8 carbon atoms. Lactonic group containing a long chain aliphatic linear structure in the resin through ring opening reaction by applying lactone compound having 2 ring carbon atoms to 1-40% by weight of lactone-modified polyester resin solids Preparing an ester-formulated derivative A having a resin; And ring-opening the semi-ester product by using an acid anhydride capable of reacting with a large amount of residual hydroxyl groups of the derivative A resin prepared above to leave a polyvalent carboxyl group at the end of the resin, thereby deriving the carboxyl group thereof from the curing agent resin. The present invention relates to a method for preparing a lactone-modified polyester resin comprising a manufacturing step of a lactone-modified polyester resin to be used as a functional group, and a coating composition containing an acrylic copolymer resin and other additives having the resin and an epoxy group. Silver is excellent in screening and scratch resistance, and has excellent durability and acid resistance.

Description

Coating composition containing thermosetting modified polyester resin

The present invention relates to a method for preparing a thermosetting modified polyester resin for paints and to a coating composition containing the same, and more specifically, to a pigment containing a pigment to give a coloring or to give a metallic feeling using a flake. Heat for the manufacture of paints that require pollution, weather resistance, especially acid resistance due to external influences when exposed to the exterior of automotive top coatings and general industrial and P.M. paint compositions coated with wet on wet method A method for producing a curable modified polyester resin and a coating composition containing the same.

Conventional acrylic or polyester top coat paints have been frequently used as acrylic melamine resins or polyester melamine resin type thermosetting solvent paints, but these acrylic melamine resin paints or polyester melamine resin type thermosetting solvent paints are currently used worldwide. As a serious problem, there is a significant problem in corrosion resistance and poor durability of paint due to acid rain or acid environment of the industrial area.

As a countermeasure against this, two-pack type using polyols such as acrylic polyol or polyester polyol and polyisocyanate curing agent and one pack type car block using isocyanate curing agent Solvent acid and gloss and durability have been solved through the development of paints and industrial paints.However, due to the strong reactivity of polyisocyanate with moisture, it is not only necessary to change the existing paint line equipment but also to avoid workers' work due to toxicity problems. In terms of problems and physical properties, there are drawbacks such as weather resistance and yellowing, which do not satisfy the needs of buyers.

On the other hand, as a linear patent related to the present invention, U.S. Pat. Nos. 4,727,518,4681811,4732790,4755582,476.440, and Japanese Patent Laid-Open Nos. 62-87288, 63-175076, and Japanese Patent Laid-Open Nos. 1-165670, but the resin composition according to the patent has a high crystallinity due to the strong water-binding group due to the polyhydric carboxylic acid compound having a molecular weight distribution of less than 1000, and due to the limitation of the solvent solubility of the general non-polar solvents and the solid content There is a problem with anger.

In order to solve the above-mentioned problems, the present invention imparts a long-chain aliphatic linear structure through lactone modification to one or more various glycol raw materials having at least two functionalities, thereby forming a -CH ₂ -repeating structure in the skeleton. As a result, the molecular weight of the resin composition can be adjusted to 1000 or more when producing the final curing agent, thereby improving the dissolving power of the non-polar solvents and obtaining the advantage of high solidification.Because of the small molecular weight of conventional resins, The problems of scratching, chipping resistance, proing and poor storage stability of the cured coating due to the proper arrangement of the properties of the lactone raw material in the resin skeleton to improve the disadvantages of the cured coating film, based on this, the present invention was completed.

Accordingly, an object of the present invention is to provide a method for preparing a thermosetting resin for a topcoat, which has excellent durability, excellent clarity and acid resistance, and excellent resistance to weatherability, acid resistance and other chemical and mechanical properties related to the environment of a paint coating to be prepared as a topcoat and It is to provide a coating composition containing.

The method for producing a thermosetting resin of the present invention for achieving the above object is a ring-opening polymerization of a lactone compound having at least one C2-20 alkylene glycol component having 2 or more carbon atoms and a ring carbon atom having 6 to 8 carbon atoms in the resin. To prepare a lactone-modified polyester resin by preparing an ester-forming derivative A resin, and then ring-opening the semi-ester product using an acid stormwater capable of reacting with a large amount of residual hydroxyl groups of the prepared derivative A resin. The coating composition of the present invention is prepared by blending the lactone-modified polyester resin, an acrylic copolymer resin having an epoxy group, and other additives.

Hereinafter, the present invention will be described in more detail.

(A) Production of lactone modified polyester resin

A lactone compound having at least one bifunctional or higher alkylene glycol component having 2 to 20 carbon atoms and a ring carbon atom having 6 to 8 carbon atoms is ring-open-polymerized by using 1 to 40% by weight of the lactone-modified polyester resin in a chain opening polymerization. An ester-forming derivative A resin having a polyfunctional hydroxyl group containing the long aliphatic linear structure was prepared, and then an acid anhydride capable of reacting with a large amount of remaining hydroxyl groups of the prepared derivative A resin was used. The semi-ester product is ring-opened to prepare a lactone-modified polyester resin having a polyvalent carboxyl group at the resin end.

Alkylene glycols containing about 2-20 carbon atoms which can be used in the present invention are preferably divalent, trivalent, tetravalent and hexavalent glycols, for example ethylene glycol, 1, 2-propane diol, Neopentyl glycol, diethylene glycol, 1, 4-butanediol, trimethylol propane, pentaerythritol, di-pentaerytriol, di-trimethylol propane, hydroxy pivalyl hydroxy pivalate (isotman : HPHP), aliphatic polyols or aromatic polyols.

Examples of the lactone compound include ε-caprolactone, β-methyl-ζ-valerolactone, δ-caprolactone, γ-caprolactone, or γ-butyrolactone, and the carboxyl group which is multivalent to the resin terminal group. The content of the lactone compound in the lactone-modified polyester resin contained is preferably 1 to 40% by weight, more preferably 5 to 25% by weight, if it exceeds 40% by weight, the hardness is lowered and the main resin Too few sites capable of an acid curing reaction with the (epoxy-containing acrylic resin) have disadvantages such as low moisture resistance, weather resistance and resistance to chemicals.

In the present invention, it is preferable to use a catalyst for the ring opening reaction between lactones and glycols, and tin catalysts, organic lead or manganese compounds are suitable as the catalyst used, and specific examples thereof include tetraphenyltin and tetraoctyltin. , Diphenyl tin laurate, dimethyl tin oxad, dibutyl tin oxide, lead acetate or magnesium acetate and the like.

Further, in order to leave a carboxyl group at the terminal of the resin, glycol and a reactable acid anhydride are reacted to open the ring of the anhydride. Acid anhydrides that may be used here include cyclic and aromatic carbons having 4-12 carbon atoms, for example phthalic anhydride, succinic anhydride, methyl succinic anhydride, octadecanylsuccinic anhydride, tetra Hydrophthalic unhydride, tetrahydro phthalic octadecanylsuccinic anhydride, tetrahydro phthalic unhydride, methyl, tetra phthalic unhydride, hexa hydro phthalic unhydride, alkylhexa hydro phthalic Unhydrides, itaconic unhydrides, citaconic unhydrides or crorendic unhydrides, the amount of which is used such that the molar ratio of acid to residual glycol equivalents is 1.0 or less and more preferably 0.8-0.95. The final resin prepared according to this method has an acid value of 400 mgKOH / g or less, an equivalent of carboxylic acid at the end of the resin of 700 or less, a number average molecular weight of about 1000-5000, preferably 100-3000. The molecular weight is determined by gel permeation chromatography using polystyrene as a standard and the molecular weight obtained in this way is not a substantial molecular weight but a molecular weight compared to polystyrene.

I. Preparation of Acrylic Copolymer Resin with Epoxy Group

The monomer having an epoxy group and other mixed monomers and polymerization initiators are uniformly mixed to polymerize the acrylic copolymer resin having an epoxy group.

Looking at the specific conditions of the production method, the monomer having an epoxy group glycidyl methacrylate, glycidyl acrylate, methyl glycidyl methacrylate, methyl glycidyl acrylate, aryl glycidyl ether is 1 The amount of the acrylic monomer having the epoxy group should be adjusted so that the epoxy equivalent is 150-1000, and when the epoxy equivalent is 1000 or more, the curing property of the paint is insufficient and the pencil hardness and solvent resistance are poor. In the case where the epoxy equivalent is less than or equal to 150, the appearance of poor physical properties of the coating film can be obtained.

And other monomers that can be used include methyl methacrylate, methyl acrylate, ethyl methacrylate, ethyl acrylate, propyl methacrylate, methyl acrylate, ethyl methacrylate, ethyl acrylate, propyl methacrylate, propyl acryl Rate, n-butyl methacrylate, n-butyl acrylate, isobutyl methacrylate, isobutyl acrylate, t-butyl methacrylate, t-butyl acrylate, 2-ethylhexyl methacrylate, 2-ethyl Hexyl acrylate, stearyl methacrylate, 2-ethylhexyl methacrylate, 2-ethylhexyl acrylate, stearyl methacrylate, stearyl acrylate, cyclohexyl methacrylate, cyclohexyl acrylate, benzyl Methacrylate, benzyl acrylate, hydroxye Methacrylate, hydroxy ethyl acrylate, hydroxy propyl methacrylate, hydroxy propyl acrylate, methyl methacrylate, acryloxide, styrene monomer, butyl acrylate or ethyl hexyl acrylate, etc. It can be used as a solution polymerization method.

The polymerization initiators include peroxides such as benzyl peroxide, di-butyl butyl peroxide, di-cumyl peroxide, Q-man hydro peroxide, and tertiary amyl peroxide and azo initiators. 2-15% by weight is suitable for the total weight of the equivalents.

In addition, 2-mercapto ethanol, benzene thioethanol or butyl mercaptan can be used as a chain transfer agent for molecular weight control of the acrylic polymer within 10% by weight based on the total weight, and the thermosetting solvent type of the present invention. Solvents used in paints include methyl amyl ketone, xylene, toluene, dodolol P.M., etapro E.P, cellulose part acetate, cocosol 100 or cocosol 150.

All. Preparation of Paint Composition

The coating composition of the present invention is prepared by blending the acid group of the lactone-modified polyester resin (A) and the epoxy group in the acrylic polymer resin (B) in an equivalent ratio of 1: 0.5-0.5: 1. If necessary in the formulation, a catalyst of a metal salt, an amine, or a leunic acid may be used to control the baking temperature at the time of curing. The amount of the compound may vary depending on the type of catalyst, but may be 3% by weight or less based on the total solids. Preferably it is 2 weight% or less. In addition, as the modifier for improving the hardness and UV absorber, and improving the physical properties of the paint as necessary, a melamine resin or an amino group-containing resin is blended, and aromatic and aliphatic hydrocarbon solvents are used for thinners. Although it can be adjusted, the amount of the melamine resin used is preferably 20% by weight or less, and more preferably 10% by weight or less.

On the other hand, the base coat paint to be used is prepared using an acrylic melamine resin-based polyester melamine-based metal pigments and colorants usually applied to automotive paints.

la. Application system of paint

The coating composition of the present invention relates to a cree coat for automobiles, the use system of which is wet-on-wet after leaving a fresh base at room temperature for 1-10 minutes after application of a conventional base coat (metallic or solid color). Apply the CREE coat with (WET-ON-WET) and leave for 5 to 20 minutes, then bake the applied coating at about 80-180 ° C for about 5-60 minutes.

Hereinafter, the present invention will be described in more detail with reference to Preparation Examples, Examples, and Comparative Examples, but the present invention is not limited thereto.

[Production Example 1]

[Lactone Modified Polyester Resin Manufacture (P / E-1)]

250 g of ditrimethyrol propane, 25 g of TONE MONOMER EC (trade name of UCC) and 0.1 g of pesket (catalyst, MT CHEM) were added to a reaction tank, and the reaction was maintained for about 4 hours after the temperature was raised to 150 ° C. under a nitrogen atmosphere.

The temperature was cooled to 110 ° C. and 350 g of Actapro E. solvent was added and 670 g of methyl hexa hydrophthalic anhydride was dropped over 2 hours.

After heating up to 130 ° C., the reaction was cooled after the reaction until the anhydride was removed. After completion of the reaction, 150 g of the etapro E. p. Solvent was diluted and cooled to room temperature. At this time, the resin having a solid content of 65.5%, an acid value of 240, and a number average molecular weight of 1050 were obtained.

[Production Example 2]

[Lactone Modified Polyester Resin Manufacture (P / E-2)]

295 g of ditrimethyrol propane, 16 g of glycerin, 31 g of TONE MONOMER EC, and 0.1 g of pesket were added to a reaction tank, and the reaction was maintained for about 4 hours after the temperature was raised to 150 ° C. under a nitrogen atmosphere.

The temperature was cooled to 110 ° C., 400 g of etapro E.P solvent was added, and 640 g of methyl hexa hydrophthalic anhydride was dropped over 2 hours.

Thereafter, the temperature was raised to 130 ° C. and reacted until the anhydride was removed. After completion of the reaction, 230 g of etapro E. p. Solution was diluted and cooled to room temperature. In this case, a resin having a solid content of resin of 65.4% of 235 and a number average molecular weight of 950 was obtained.

[Manufacture example 3]

[Lactone Modified Polyester Resin Manufacture (P / E-3)]

250 g of ditrimethyrol propane, 50 g of TONE MONOMER EC, and 0.1 g of pesket were placed in a reaction tank, and the reaction was maintained for about 4 hours after the temperature was raised to 150 ° C. under a nitrogen atmosphere.

The temperature was cooled to 110 ° C., 300 g of etapro E. solvent was added, and 670 g of methyl hexa hydrophthalic anhydride was dropped over 2 hours.

Thereafter, the temperature was raised to 130 ° C. and reacted until the anhydride was removed. After completion of the reaction, 220 g of the etapro E. solvent was diluted and cooled to room temperature. At this time, resin of 65.1% of solid content of resin, the acid value of 230, and the number average molecular weight was 1100 was obtained.

[Production Example 4]

[Lactone Modified Polyester Resin Manufacture (P / E-4)]

260 g of ditrimethyrol propane, 55 g of neopentyl glycol, 47 g of TONE MONOMER EC, and 0.1 g of pesket were added to the reactor, cooled to 150 ° C. under a nitrogen atmosphere, 400 g of etapro E.P. solvent, and then methyl hexahydropropane. 840 g of talylic hydride was dropped over 2 hours.

Thereafter, the temperature was raised to 130 ° C. and reacted and cooled until the anhydride was removed upon confirmation of I.R. After completion of the reaction, 250 g of the etapro E. solvent was diluted and cooled to room temperature. At this time, the resin whose solid content was 65.5%, the acid value was 230, and the number average molecular weight was 1000.

Production Example 5

[Polyester Resin Synthesis (Comparative 1)]

After adding 125 g of ditrimethyrol propane, 68 g of TMP, and 326 g of etapro E.P solvent, the temperature was raised to 110 ° C, and 672 g of methyl hexa hydrophthalic anhydride was dropped over 2 hours. Thereafter, the temperature was raised to 130 ° C. and reacted until the anhydride was removed. After completion of the reaction, 140 g of Acti E. solution was diluted and cooled to room temperature. In this case, a resin having a solid content of resin of 65.4%, an acid value of 255, and a number average molecular weight of 850 was obtained.

[Manufacture example 6]

[Polyester Resin Synthesis (Comparative 2)]

135 g of TMP and 300 g of etapro E.P solvent were added, and the temperature was raised to 110 ° C., and 672 g of methyl hexa hydrophthalic anhydride was dropped over 2 hours. Thereafter, the reaction mixture was heated up to 130 ° C. and reacted until the anhydride was removed. After the reaction was completed, 135 g of the etapro E. p. Solvent was diluted and cooled to room temperature. At this time, the solid content of resin was 65.2%, the acid value was 270, and the resin of number average molecular weight was 700 was obtained.

[Manufacture example 7]

[Polyester Resin Synthesis (Comparative 3)]

After adding 94 g of glycerin and 300 g of etapro E.P. solvent, the temperature was raised to 110 ° C. and 672 g of methyl hexa hydrophthalic anhydride was dropped over 2 hours. Thereafter, the temperature was raised to 130 ° C. and reacted until the anhydride was removed. After completion of the reaction, 110 g of the etapro E. solvent was diluted and cooled to room temperature. In this case, a resin having a solid content of resin of 65.2%, an acid value of 290, and a number average molecular weight of 650 was obtained.

[Manufacture example 8]

[Epoxy-containing acrylic copolymer resin (EP-1)]

520 g of xylene was added to a clean reaction tank, and the temperature was slowly raised to reflux. In separate monomer tank for acrylic synthesis, 296.4 g glycidyl methacrylate, 195 g butyl acrylate, 140.4 g normal-butyleta acrylate, 117 g methyl methacrylate, 31.2 g styrene monomer, tertiary butyl peroxy benzoate 46.8 The g was uniformly mixed well, then uniformly dropping over 3 hours, held for 4 hours, and cooled to room temperature. At this time, resin of 59.8% of solid content of resin, epoxy equivalent of 374, glass transition temperature of 14.7 degreeC, and number average molecular weight of 1350 was obtained.

[Manufacture example 9]

[Epoxy-containing acrylic copolymer resin (EP-2)]

520 g of xylene was added to a clean reaction tank, and the temperature was slowly raised to reflux. In a separate acrylic tank for molding acrylic, glycidyl methacrylate 327.6 g butyl acrylate 78.0 g, normal- butyl methacrylate 156.0 g, methyl methacrylate 156.0 g, styrene monomer 62.4 g, butyl butyl peroxy benzoate After mixing 54.5g well and uniformly dropping reaction over 3 hours and maintained for 4 hours and then cooled to room temperature. At this time, the resin which is about 60.4% of solid content of resin, epoxy equivalent 338, glass transition temperature of 37.3 degreeC, and number average molecular weight 1150 was obtained.

[Production Example 10]

[Epoxy-containing acrylic copolymer resin (EP-3)]

520 g of xylene was added to a clean reaction tank, and the temperature was slowly raised to reflux. Separate monomer tank for acrylic synthesis: 273.0 g glycidyl methacrylate, 78.0 g butyl acrylate, 156.0 g normal-butylmethacrylate, 156.0 g methyl methacrylate, 117 g 2-ethylhexyl acrylate, tertiary butyl After mixing 40.5 g of peroxy benzoate uniformly well, it was uniformly dropped over 3 hours, held for 4 hours, and then cooled to room temperature. In this case, a resin having a solid content of 60.1%, an epoxy equivalent of 406, a glass transition temperature of 6.1 ° C, and a number average molecular weight of 1590 was obtained.

[Production Example 11]

[Epoxy-containing acrylic copolymer resin (EP-4)]

520 g of xylene was added to a clean reaction tank, and the temperature was slowly raised to reflux. 351.0 g glycidyl methacrylate, 78.0 butyl acrylate, 117.0 g normal-butyl methacrylate, 78.0 g 2-methylhexyl acrylate, 78.0 g 2-butylhexyl acrylate in separate monoder tanks for acrylic synthesis After mixing 50.2 g of peroxy benzoate uniformly well, it was uniformly dropped over 3 hours, held for 4 hours, and cooled to room temperature. In this case, a resin having a solid content of 59.4%, an epoxy equivalent of 315, a glass transition temperature of 15.6 ° C, and a number average molecular weight of 1280 was obtained.

Example 1-4 Comparative Example 1-3

The lactone-modified polyester resin according to Preparation Example 1-4 and the acrylic copolymer resin having an epoxy group according to Preparation Example 8-11 were combined with other additives in the same ratio as in Table 3 to prepare a paint composition according to the present invention. (Example 1-4), and a conventional polyester resin according to Preparation Example 5-7 and an acrylic copolymer resin having an epoxy group according to Preparation Example 8-10 together with other additives in a proportion as shown in Table 3 below. To prepare a paint composition (Comparative Examples 1-3).

Physical properties of the paint compositions according to the Examples and Comparative Examples were shown in Table 4 below.

The lactone-modified polyester resin prepared by the present invention provides a long chain aliphatic linear structure in the polyester resin through modification of the lactone raw material to one or more various glycol raw materials having bifunctional or more than two functionalities, so that the molecular weight is controlled to 1000 or more. It is possible to select various solvents because it has good dissolving power in non-polar solvents, and it has the advantage of high solidification, and it gives the properties of lactone raw material to give the good filminess and scratch property of coating film and acid curing reaction with epoxy group. It has excellent durability and excellent acid resistance related to the environment of the coating film.

Claims (2)

1-40% by weight of a lactone compound having at least one bifunctional or higher alkylene glycol component having 2 to 20 carbon atoms and a ring carbon atom having 6 to 8 carbon atoms to the lactone-modified polyether resin solid to undergo a ring-opening reaction. Preparing an ester-forming derivative A resin having a large amount of polyfunctional hydroxyl groups containing a long aliphatic linear structure in the resin; And ring-opening the semi-ester product using an acid anhydride capable of reacting with a large amount of residual hydroxyl groups of the derivative A resin to leave a polyvalent carboxyl group at the end of the resin so that the induced carboxyl group is a functional group of the curing agent resin. Acid containing 400 mgKOH / g or less, 700 or less equivalent of carboxylic acid at the end of resin, Lactone-modified polyester resin having an average number of molecular weight of about 1000-5000 and acrylic group containing epoxy group A coating composition containing a copolymer resin and other additives, wherein an acid group of the lactone-modified polyester resin and an epoxy group in an acrylic copolymer resin are blended in an equivalent ratio of 1: 0.5-0.5: 1. The paint composition of claim 1, wherein the other additives are catalysts, appearance modifiers, ultraviolet absorbers, and modifiers.