CA2083225C - Hard, flexible and durable architectural coating - Google Patents
Hard, flexible and durable architectural coatingInfo
- Publication number
- CA2083225C CA2083225C CA 2083225 CA2083225A CA2083225C CA 2083225 C CA2083225 C CA 2083225C CA 2083225 CA2083225 CA 2083225 CA 2083225 A CA2083225 A CA 2083225A CA 2083225 C CA2083225 C CA 2083225C
- Authority
- CA
- Canada
- Prior art keywords
- polyol
- composition
- mole percent
- acyclic
- mixture
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D167/00—Coating compositions based on polyesters obtained by reactions forming a carboxylic ester link in the main chain; Coating compositions based on derivatives of such polymers
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
- C08G63/12—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from polycarboxylic acids and polyhydroxy compounds
- C08G63/16—Dicarboxylic acids and dihydroxy compounds
- C08G63/18—Dicarboxylic acids and dihydroxy compounds the acids or hydroxy compounds containing carbocyclic rings
- C08G63/199—Acids or hydroxy compounds containing cycloaliphatic rings
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D167/00—Coating compositions based on polyesters obtained by reactions forming a carboxylic ester link in the main chain; Coating compositions based on derivatives of such polymers
- C09D167/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/31504—Composite [nonstructural laminate]
- Y10T428/31678—Of metal
- Y10T428/31681—Next to polyester, polyamide or polyimide [e.g., alkyd, glue, or nylon, etc.]
Abstract
A low cost, high performance coating for sheet metal which is to be formed into siding for houses and automobile panels is made from a polyester prepared by the condensation of hexahydrophthalic acid and a mixture of 1,4-cyclohexanedimethanol and an acyclic polyol wherein the mole percent of acyclic polyol is from 50 to 60; and a crosslinking agent containing the -N-CH2-OR moiety wherein R is hydrogen or an alkyl group having from 1 to 4 carbon atoms and the unsatisfied valence is attached to an organic group capable of incorporation into a film.
Description
HARD, FLEXIBLE, AND DURABLE ARCHITECTURAL COATING
BACKGROUND OF THE INVENTION
This invention relates to coating compositions comprising a crosslinking agent containing N-methylol and/or N-methylol ether groups and linear polyesters having free hydroxyl groups and free carboxylic groups made from a cyclo- aliphatic dicarboxylic acid and a mixture of cycloaliphatic and acyclic polyols in which the latter predominate. It relates more particularly to coatings which because of their superior flexibility, hardness, and weatherability are especially useful on architectural siding and on automobiles.
Coatings said to have the somewhat mutually antagonistic properties of a high degree of elasticity and a high degree of hardness, as well as high gloss and resistance to weathering are taught in U.S. Patent No. 3,668,275. These coatings are made from linear polyesters wherein at least 70 and preferably 80 mole percent of the dihydric alcohol moiety is derived from 1,4-bis-(hydroxymethyl)-cyclohexane and as much as gl mole percent, preferably at least 50 mole percent, of the dicarboxylic acid moiety is derived from an aromatic or cycloaliphatic dicarboxylic acid. A preference for aromatic acids is shown in the working examples of the polyester and coatings therefrom.
In U.S. Patent No. 2,901,466, Eastman Kodak Company discloses highly polymeric linear polyesters which because of their surprisingly high melting points are especially advantageous in the formation of fibers and films. Such polyesters are prepared by condensing 1,4-bis-(hydroxymethyl) cyclohexane, also known as 1,4-cyclohexane dimethanol or CHDM, with a hexacarbocyclic dicarboxylic acid. The highest melting ~i~
polyesters are preferably prepared from a diol composition containing at least 50 mole percent of the CHDM and up to 50 mole percent of another diol and an acid composition containing at least 50 mole percent of a hexacarbocyclic dicarboxylic compound and up to about 50 mole percent of another bifunc-tional dicarboxylic compound.
State of the art architectural coatings, however, still rely on silicone protected polyester backbones to boost their exterior durability to acceptable levels. Such state of the art coatings, however, are characterized by high cost, poor hardness and poor flexibility.
SUMMARY OF THE INVENTION
It is an object of this invention, therefore, to provide a low cost, high performance coating for metal substrates which are subjected to sharp bending operations, such as architectural siding and sheet metal for automobiles, and then must withstand prolonged exposure to strong ultraviolet light.
It is a related object of this invention to provide such a coating wherein at least half of the polyol moiety of the polyester backbone is derived from an acyclic polyol.
It is another object of this invention to provide a coating which because of its excellent hardness and formability is particularly adapted to the coil coating technique.
These and other objects which will become apparent from the following disclosure are attained by a coating composition consisting essentially of:
a polyester prepared by the condensation of hexahydro-phthalic acid and a mixture of 1,4-cyclohexanedimethanol and an acyclic polyol wherein the mole percent of the acyclic polyol is from 50 to 60; and a crosslinking agent containing the -N-CH2-OR moiety wherein R is hydrogen or an alkyl group having from 1 to 4 carbon atoms and the PATENT
2ù83225 unsatisfied valence is attached to an organic group capable of incorporation into a film.
DETAILED DESCRIPTION OF THE INVENTION
The hexahydrophthalic acid may be the 1,2-, 1,3- or 1,4-isomer. The 1,4- isomer is often called 1,4-cyclohexane-dicarboxylic acid. In place of the free dicarboxylic acid, the esters thereof with short chain alkanols, e.g., dimethyl, diethyl, or dipropyl esters, can also be employed. Hexahydro-phthalic anhydride is preferable in many instances. Also contemplated as the acid in the condensation re~ction are the alkyl hexahydrophthalic acids and anhydrides wherein an alkyl group having up to about seven carbon atoms is bound to the cycloaliphatic ring. For the purposes of this invention, therefore, the term hexahydrophthalic acid shall include in its meaning the esters, the anhydride, and the ring-alkylated derivatives of each.
Suitable acyclic polyols are exemplified by 1,6-hexane-diol; pentaerythritol; trimethylolpropane; 2-methyl-1,3-pro-panediol; neopentyl glycol; 2-butyl- 2-ethyl-1,3-propanediol;
ethylene glycol; 1,4-butanediol; 1,3-butanediol; 1,5-pentane-diol; and trimethylolethane. The polyols having more than two hydroxy groups are used to provide a branched structure which imparts some degree of chemical resistance, durability and stain resistance, depending on the relative amounts used, but at the expense of flexibility and solution viscosity. Whereas the total amount of acyclic polyols is, as aforesaid, 50 mole percent or more of the polyol mixture, the portion having more than two hydroxy groups is suitably from about 4 to about 20 mole percent of the acyclic total. It is preferred to use from about 5 to about 15 mole percent of tri- or tetrahydric alcohols in the polyol mixture.
The N-methylol- and N-methylol ether groups represented by the -N-CH2-OR formula given above are found in the polymers and oligomers commonly known as aminoplasts and are the reaction products of aldehydes, particularly formaldehyde, with amino-or amido-group-carrying substances exemplified by melamine, urea, dicyanodiamide, and benzoguanamine. Other polymers having such groups may be obtained following the methods described in U.S. Patent No. 2,940,944 and German patent applications 1,060,596; 1,083,548; and 1,089, 549. Especially advantageous are the aminoplasts which are modified with alkanols having from one to four carbon atoms. It is preferable in many instances to employ precursors of aminoplasts such as hexa-methylol melamine, dimethylol urea, hexamethoxymethyl melamine, and the etherified forms of the others, all of which are repre-sented by the formula given above. Thus a wide variety of commercially available aminoplasts and their precursors can be used for combining with the linear polyesters of this inven-tion. Particularly preferred are the amino crosslinking agents sold by American Cyanamid under the trademark Cymel. In particular, the Cymel 301, Cymel 303, and Cymel 385 alkylated melamine-formaldehyde resins are useful. Of course, it is possible to use mixtures of all of the above N-methylol pro-ducts.
The amine-aldehyde materials function as a crosslinking agent in the composition by reacting with the hydroxyl functionality of the polyester. In order to achieve the outstanding properties which make these coatings particularly useful, it is essential that the amount of crosslinking agent be sufficient to substantially completely react with the hydroxyl functionality present. Therefore, the amount of crosslinking agent should be sufficient to provide from about 2 to about 12 equivalents of nitrogen crosslinking functionality for each equivalent of hydroxyl functionality in the polyester.
The linear polyesters of this invention generally have an acid number of from about 1 to about 12, preferably from about 5 to about 10, and a hydroxyl number of from about 10 to about 120, preferably from about 20 to about 50. They may be produced by any of the conventional processes at temperatures up to about 250C or higher. The use of a catalyst is preferred as is the passage of an inert gas through the reaction mixture to protect against discoloration and to aid in the liberation of water from the mixture as it is produced by the condensation. The esterification takes place almost quantitatively and may be monitored by determining the acid and hydroxyl numbers or by monitoring the Gardner-Holt viscosity of the product.
For producing the coating composition, the polyester and the crosslinking agent are suitably first dissolved in a conventional solvent such as toluene, xylene, butanol, butyl acetate, ethylene glycol, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and mixtures thereof. The weight ratio of the polyester to the aminoplast may be from 90:10 to 60:40.
The binder, i.e., polyester plus crosslinker, constitutes from about 30 to about 50 percent of the composition by weight.
Additives and auxiliary substances such as pigments, flow modifiers, viscosity modifiers, and other binders may be dispersed in the coating composition. A catalytic amount of a strong acid such as p-toluenesulfonic acid may be added to the composition just before it is applied to a substrate to hasten the crosslinking reaction.
The composition thus obtained may be applied to sheet metal such as is used for automobile and airplane bodies;
architectural metal skins, e.g., siding and window frames; and the like by spraying, dipping, or brushing but it is particu-larly suited for a coil coating operation wherein the compos-ition is wiped onto the sheet as it unwinds from a coil and then baked as the sheet travels toward an uptake coil winder.
It is also contemplated for use in the so-called "plate coater", available from Alcan Aluminum, whereby the composition is extruded as a thin coating onto the sheet metal and then smoothed by a doctor blade. The baking temperature in any event may be from about 100C to about 300C.
PREPARATION OF POLYESTERS
A B C D
In~redients qrams moles qrams moles ~rams moles qrams moles HHPA 770.2 5.00 514.0 3.33 636.2 4.13 514.0 3.33 NPG 381.5 3.67 338.8 3.26 235.8 2.27 381.5 3.67 1,4-CHDA 286.6 1.67 573.6 3.33 --- --- 573.7 3.33 1,4-CHDM, 90% 588.6 3.67 521.2 3.26 363.1 2.27 587.7 3.67 Trimethylolethane --- --- 65.9 0.55 --- --- --- ---Butylstannoic acid2.0 2.0 1.1 2.0 Acid Value A Acid Value A Acid Value A Acid Value A
10.1 Viscosity A Viscosity A Viscocity A Viscosity A
H P G-H L+
qrams ~rams qrams qrams Aromatic Naptha915.5 915.5 640.0 1066.7 Xylene 52.1 52.1 40.0 66.7 Isobutyl alcohol171.1 171.1 120.00 200.0 Solids (% wt) 61.0 61.0 60.5 60.6 Acid value B 6.9 8.8 3.9 4.6 Density 1.059 1.058 --- ---Viscosity B Z1-Z2 Z4- Z1 Z2 HHPA is hexahydrophthalic anhydride NPG is neopentyl glycol 1,4-CHDA is 1,4-cyclohexanedicarboxylic acid 1,4-CHDM is 1,4-cyclohexane dimethanol The reactants shown in Table 1 were charged to a reactor equipped with an agitator, inert gas inlet, packed column, condenser, and thermometer. The reactor was flushed with inert gas and the reactants were heated to about 232C (360F) in about 2 hours while removing water. After an additional 3.5 hours, approximately, at 230C, the acid value A and the Gardner Bubble viscosity A of a sample at 60% by weight solids in xylene were as shown in Table 1. After about another 20 minutes, the batch was cooled and reduced with the solvents as shown in Table 1. The solids content, acid value B, density, and viscosity B of the resulting solutions are as shown in Table 1.
The following specific embodiments are illustrative of the invention described and claimed herein. All parts are by weight unless otherwise stated.
Coating compositions 1 and 2 were made from polyester A
and B, respectively, by first dispersing 118.2 parts of TiO2 and 47.3 parts of Cr20~ in 259.7 parts of the polyester solution and 38.6 parts of dipropylene glycol monomethyl ether until a Hegman reading of 7+ was obtained. Subsequently, 44.9 parts of Cymel 303, 31.7 parts of Cymel 385, 20.0 parts of dipropylene glycol monomethyl ether, 12.0 parts of 2-ethyl-hexanol, 12.0 parts of l-butanol, 7.1 parts of a flow additive, and 15.9 parts of a 10% p-toluenesulfonic acid solution were added and mixed. The coating compositions were then adjusted to 25-30 seconds on a #4 Zahn cup with dipropylene glycol mono-methyl ether. The coating compositions of Examples 3 and 4 were made according to this general procedure from Polyesters C and D, respectively.
The coating compositions were applied to aluminum panels and baked for 21 seconds at 560F (293C) to yield coatings having a thickness of about 0.76-0.78 mil. All four coatings had an H pencil hardness and were resistant to MEK. The coatings of Examples 1 and 2 had a 1-2T flexibility and the coatings of Examples 3 and 4 had a flexibility of 2T as measured by the ASTM D4145-83 procedure. The coated panels were each placed in a QW cabinet and after 1000 hours of exposure to the test conditions prescribed in the ASTM G53-88 procedure the coating from Example 1 retained 46.5 % of its original gloss; that from Example 2 retained 39.6 % ; that from Example 3 retained 31.9%; and that from Example 4 retained 37.670. A commercial coating made from a silicone-protected polyester retained but 25 % of its original gloss after 1000 hours and a coating based on a conventional orthophthalate/iso-phthalate polyester retained only 2 % after 618 hours of exposure in the QW test.
BACKGROUND OF THE INVENTION
This invention relates to coating compositions comprising a crosslinking agent containing N-methylol and/or N-methylol ether groups and linear polyesters having free hydroxyl groups and free carboxylic groups made from a cyclo- aliphatic dicarboxylic acid and a mixture of cycloaliphatic and acyclic polyols in which the latter predominate. It relates more particularly to coatings which because of their superior flexibility, hardness, and weatherability are especially useful on architectural siding and on automobiles.
Coatings said to have the somewhat mutually antagonistic properties of a high degree of elasticity and a high degree of hardness, as well as high gloss and resistance to weathering are taught in U.S. Patent No. 3,668,275. These coatings are made from linear polyesters wherein at least 70 and preferably 80 mole percent of the dihydric alcohol moiety is derived from 1,4-bis-(hydroxymethyl)-cyclohexane and as much as gl mole percent, preferably at least 50 mole percent, of the dicarboxylic acid moiety is derived from an aromatic or cycloaliphatic dicarboxylic acid. A preference for aromatic acids is shown in the working examples of the polyester and coatings therefrom.
In U.S. Patent No. 2,901,466, Eastman Kodak Company discloses highly polymeric linear polyesters which because of their surprisingly high melting points are especially advantageous in the formation of fibers and films. Such polyesters are prepared by condensing 1,4-bis-(hydroxymethyl) cyclohexane, also known as 1,4-cyclohexane dimethanol or CHDM, with a hexacarbocyclic dicarboxylic acid. The highest melting ~i~
polyesters are preferably prepared from a diol composition containing at least 50 mole percent of the CHDM and up to 50 mole percent of another diol and an acid composition containing at least 50 mole percent of a hexacarbocyclic dicarboxylic compound and up to about 50 mole percent of another bifunc-tional dicarboxylic compound.
State of the art architectural coatings, however, still rely on silicone protected polyester backbones to boost their exterior durability to acceptable levels. Such state of the art coatings, however, are characterized by high cost, poor hardness and poor flexibility.
SUMMARY OF THE INVENTION
It is an object of this invention, therefore, to provide a low cost, high performance coating for metal substrates which are subjected to sharp bending operations, such as architectural siding and sheet metal for automobiles, and then must withstand prolonged exposure to strong ultraviolet light.
It is a related object of this invention to provide such a coating wherein at least half of the polyol moiety of the polyester backbone is derived from an acyclic polyol.
It is another object of this invention to provide a coating which because of its excellent hardness and formability is particularly adapted to the coil coating technique.
These and other objects which will become apparent from the following disclosure are attained by a coating composition consisting essentially of:
a polyester prepared by the condensation of hexahydro-phthalic acid and a mixture of 1,4-cyclohexanedimethanol and an acyclic polyol wherein the mole percent of the acyclic polyol is from 50 to 60; and a crosslinking agent containing the -N-CH2-OR moiety wherein R is hydrogen or an alkyl group having from 1 to 4 carbon atoms and the PATENT
2ù83225 unsatisfied valence is attached to an organic group capable of incorporation into a film.
DETAILED DESCRIPTION OF THE INVENTION
The hexahydrophthalic acid may be the 1,2-, 1,3- or 1,4-isomer. The 1,4- isomer is often called 1,4-cyclohexane-dicarboxylic acid. In place of the free dicarboxylic acid, the esters thereof with short chain alkanols, e.g., dimethyl, diethyl, or dipropyl esters, can also be employed. Hexahydro-phthalic anhydride is preferable in many instances. Also contemplated as the acid in the condensation re~ction are the alkyl hexahydrophthalic acids and anhydrides wherein an alkyl group having up to about seven carbon atoms is bound to the cycloaliphatic ring. For the purposes of this invention, therefore, the term hexahydrophthalic acid shall include in its meaning the esters, the anhydride, and the ring-alkylated derivatives of each.
Suitable acyclic polyols are exemplified by 1,6-hexane-diol; pentaerythritol; trimethylolpropane; 2-methyl-1,3-pro-panediol; neopentyl glycol; 2-butyl- 2-ethyl-1,3-propanediol;
ethylene glycol; 1,4-butanediol; 1,3-butanediol; 1,5-pentane-diol; and trimethylolethane. The polyols having more than two hydroxy groups are used to provide a branched structure which imparts some degree of chemical resistance, durability and stain resistance, depending on the relative amounts used, but at the expense of flexibility and solution viscosity. Whereas the total amount of acyclic polyols is, as aforesaid, 50 mole percent or more of the polyol mixture, the portion having more than two hydroxy groups is suitably from about 4 to about 20 mole percent of the acyclic total. It is preferred to use from about 5 to about 15 mole percent of tri- or tetrahydric alcohols in the polyol mixture.
The N-methylol- and N-methylol ether groups represented by the -N-CH2-OR formula given above are found in the polymers and oligomers commonly known as aminoplasts and are the reaction products of aldehydes, particularly formaldehyde, with amino-or amido-group-carrying substances exemplified by melamine, urea, dicyanodiamide, and benzoguanamine. Other polymers having such groups may be obtained following the methods described in U.S. Patent No. 2,940,944 and German patent applications 1,060,596; 1,083,548; and 1,089, 549. Especially advantageous are the aminoplasts which are modified with alkanols having from one to four carbon atoms. It is preferable in many instances to employ precursors of aminoplasts such as hexa-methylol melamine, dimethylol urea, hexamethoxymethyl melamine, and the etherified forms of the others, all of which are repre-sented by the formula given above. Thus a wide variety of commercially available aminoplasts and their precursors can be used for combining with the linear polyesters of this inven-tion. Particularly preferred are the amino crosslinking agents sold by American Cyanamid under the trademark Cymel. In particular, the Cymel 301, Cymel 303, and Cymel 385 alkylated melamine-formaldehyde resins are useful. Of course, it is possible to use mixtures of all of the above N-methylol pro-ducts.
The amine-aldehyde materials function as a crosslinking agent in the composition by reacting with the hydroxyl functionality of the polyester. In order to achieve the outstanding properties which make these coatings particularly useful, it is essential that the amount of crosslinking agent be sufficient to substantially completely react with the hydroxyl functionality present. Therefore, the amount of crosslinking agent should be sufficient to provide from about 2 to about 12 equivalents of nitrogen crosslinking functionality for each equivalent of hydroxyl functionality in the polyester.
The linear polyesters of this invention generally have an acid number of from about 1 to about 12, preferably from about 5 to about 10, and a hydroxyl number of from about 10 to about 120, preferably from about 20 to about 50. They may be produced by any of the conventional processes at temperatures up to about 250C or higher. The use of a catalyst is preferred as is the passage of an inert gas through the reaction mixture to protect against discoloration and to aid in the liberation of water from the mixture as it is produced by the condensation. The esterification takes place almost quantitatively and may be monitored by determining the acid and hydroxyl numbers or by monitoring the Gardner-Holt viscosity of the product.
For producing the coating composition, the polyester and the crosslinking agent are suitably first dissolved in a conventional solvent such as toluene, xylene, butanol, butyl acetate, ethylene glycol, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and mixtures thereof. The weight ratio of the polyester to the aminoplast may be from 90:10 to 60:40.
The binder, i.e., polyester plus crosslinker, constitutes from about 30 to about 50 percent of the composition by weight.
Additives and auxiliary substances such as pigments, flow modifiers, viscosity modifiers, and other binders may be dispersed in the coating composition. A catalytic amount of a strong acid such as p-toluenesulfonic acid may be added to the composition just before it is applied to a substrate to hasten the crosslinking reaction.
The composition thus obtained may be applied to sheet metal such as is used for automobile and airplane bodies;
architectural metal skins, e.g., siding and window frames; and the like by spraying, dipping, or brushing but it is particu-larly suited for a coil coating operation wherein the compos-ition is wiped onto the sheet as it unwinds from a coil and then baked as the sheet travels toward an uptake coil winder.
It is also contemplated for use in the so-called "plate coater", available from Alcan Aluminum, whereby the composition is extruded as a thin coating onto the sheet metal and then smoothed by a doctor blade. The baking temperature in any event may be from about 100C to about 300C.
PREPARATION OF POLYESTERS
A B C D
In~redients qrams moles qrams moles ~rams moles qrams moles HHPA 770.2 5.00 514.0 3.33 636.2 4.13 514.0 3.33 NPG 381.5 3.67 338.8 3.26 235.8 2.27 381.5 3.67 1,4-CHDA 286.6 1.67 573.6 3.33 --- --- 573.7 3.33 1,4-CHDM, 90% 588.6 3.67 521.2 3.26 363.1 2.27 587.7 3.67 Trimethylolethane --- --- 65.9 0.55 --- --- --- ---Butylstannoic acid2.0 2.0 1.1 2.0 Acid Value A Acid Value A Acid Value A Acid Value A
10.1 Viscosity A Viscosity A Viscocity A Viscosity A
H P G-H L+
qrams ~rams qrams qrams Aromatic Naptha915.5 915.5 640.0 1066.7 Xylene 52.1 52.1 40.0 66.7 Isobutyl alcohol171.1 171.1 120.00 200.0 Solids (% wt) 61.0 61.0 60.5 60.6 Acid value B 6.9 8.8 3.9 4.6 Density 1.059 1.058 --- ---Viscosity B Z1-Z2 Z4- Z1 Z2 HHPA is hexahydrophthalic anhydride NPG is neopentyl glycol 1,4-CHDA is 1,4-cyclohexanedicarboxylic acid 1,4-CHDM is 1,4-cyclohexane dimethanol The reactants shown in Table 1 were charged to a reactor equipped with an agitator, inert gas inlet, packed column, condenser, and thermometer. The reactor was flushed with inert gas and the reactants were heated to about 232C (360F) in about 2 hours while removing water. After an additional 3.5 hours, approximately, at 230C, the acid value A and the Gardner Bubble viscosity A of a sample at 60% by weight solids in xylene were as shown in Table 1. After about another 20 minutes, the batch was cooled and reduced with the solvents as shown in Table 1. The solids content, acid value B, density, and viscosity B of the resulting solutions are as shown in Table 1.
The following specific embodiments are illustrative of the invention described and claimed herein. All parts are by weight unless otherwise stated.
Coating compositions 1 and 2 were made from polyester A
and B, respectively, by first dispersing 118.2 parts of TiO2 and 47.3 parts of Cr20~ in 259.7 parts of the polyester solution and 38.6 parts of dipropylene glycol monomethyl ether until a Hegman reading of 7+ was obtained. Subsequently, 44.9 parts of Cymel 303, 31.7 parts of Cymel 385, 20.0 parts of dipropylene glycol monomethyl ether, 12.0 parts of 2-ethyl-hexanol, 12.0 parts of l-butanol, 7.1 parts of a flow additive, and 15.9 parts of a 10% p-toluenesulfonic acid solution were added and mixed. The coating compositions were then adjusted to 25-30 seconds on a #4 Zahn cup with dipropylene glycol mono-methyl ether. The coating compositions of Examples 3 and 4 were made according to this general procedure from Polyesters C and D, respectively.
The coating compositions were applied to aluminum panels and baked for 21 seconds at 560F (293C) to yield coatings having a thickness of about 0.76-0.78 mil. All four coatings had an H pencil hardness and were resistant to MEK. The coatings of Examples 1 and 2 had a 1-2T flexibility and the coatings of Examples 3 and 4 had a flexibility of 2T as measured by the ASTM D4145-83 procedure. The coated panels were each placed in a QW cabinet and after 1000 hours of exposure to the test conditions prescribed in the ASTM G53-88 procedure the coating from Example 1 retained 46.5 % of its original gloss; that from Example 2 retained 39.6 % ; that from Example 3 retained 31.9%; and that from Example 4 retained 37.670. A commercial coating made from a silicone-protected polyester retained but 25 % of its original gloss after 1000 hours and a coating based on a conventional orthophthalate/iso-phthalate polyester retained only 2 % after 618 hours of exposure in the QW test.
Claims (5)
1. A coating composition consisting essentially of a polyester prepared by the condensation of hexahydrophthalic acid and a mixture of 1,4-cyclohexanedimethanol and an acyclic polyol wherein the mole percent of the acyclic polyol is from 50 to 60; and a crosslinking agent containing the -N-CH2-OR moiety wherein R is hydrogen or an alkyl group having from one to four carbon atoms and the unsatisfied valence is attached to an organic group capable of incorporation into a film.
2. The composition of claim 1 wherein the acyclic polyol has three hydroxyl groups.
3. The composition of claim 2 wherein the tri-hydroxy polyol constitutes about eight mole percent of the weight of the polyol mixture.
4. The composition of claim 1 wherein the acyclic polyol constitutes about 56 mole percent of the polyol mixture.
5. A sheet metal panel coated with the composition of claim 1 and heated to cure the composition.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
USS.N.07/813,221 | 1991-12-23 | ||
US07/813,221 US5262494A (en) | 1991-12-23 | 1991-12-23 | Hard, flexible, and durable architectural coating |
Publications (2)
Publication Number | Publication Date |
---|---|
CA2083225A1 CA2083225A1 (en) | 1993-06-24 |
CA2083225C true CA2083225C (en) | 1995-11-07 |
Family
ID=25211803
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA 2083225 Expired - Lifetime CA2083225C (en) | 1991-12-23 | 1992-11-18 | Hard, flexible and durable architectural coating |
Country Status (9)
Country | Link |
---|---|
US (1) | US5262494A (en) |
EP (1) | EP0552540A1 (en) |
JP (1) | JPH05310901A (en) |
AU (1) | AU645445B2 (en) |
CA (1) | CA2083225C (en) |
FI (1) | FI925478A (en) |
MX (1) | MX9207124A (en) |
NO (1) | NO924718L (en) |
NZ (1) | NZ245115A (en) |
Families Citing this family (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19544737C1 (en) * | 1995-12-01 | 1996-12-12 | Synthopol Chemie Dr Koch | Binder for use in coatings, contg. di- and or poly-isocyanate, as crosslinking agent or hardener |
ES2136469T3 (en) * | 1996-02-29 | 1999-11-16 | Synthopol Chemie Dr Koch | NEW POLYESTER-POLYOLES AND THEIR USE AS POLYOL COMPONENTS IN POLYURETHANE VARNISHES OF TWO COMPONENTS. |
US6294619B1 (en) | 1999-11-02 | 2001-09-25 | Ppg Industries Ohio, Inc. | Stable powder coating compositions which produce consistent finishes |
US6284846B1 (en) | 1999-11-02 | 2001-09-04 | Ppg Industries Ohio, Inc. | Stable powder coating compositions |
AU7834300A (en) * | 1999-11-02 | 2001-05-14 | Ppg Industries Ohio, Inc. | Liquid coating compositions and coated substrates made therewith |
US6288199B1 (en) | 1999-11-02 | 2001-09-11 | Ppg Industries Ohio, Inc. | Blocked isocyanate-based compounds and compositions containing the same |
US6974631B2 (en) * | 2002-03-04 | 2005-12-13 | Valspar Sourcing, Inc. | High-reflectivity polyester coating |
US20070260012A1 (en) * | 2006-05-05 | 2007-11-08 | Algrim Danald J | HAPs free coating composition and film thereof |
US20090191407A1 (en) * | 2008-01-18 | 2009-07-30 | Lewarchik Ronald J | Coatings providing low surface emissivity |
JP5572000B2 (en) * | 2010-04-06 | 2014-08-13 | 互応化学工業株式会社 | Polyester resin composition |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
BE592181A (en) * | 1955-12-22 | |||
US3033822A (en) * | 1959-06-29 | 1962-05-08 | Eastman Kodak Co | Linear polyesters of 1, 4-cyclohexane-dimethanol and hydroxycarboxylic acids |
US2891930A (en) * | 1957-03-25 | 1959-06-23 | Eastman Kodak Co | Fiber-forming polyesters from trans-1, 4-cyclohexanedicarboxylic compounds and 1, 1-cyclohexane dimethanol |
FR1574618A (en) * | 1967-08-10 | 1969-07-11 | ||
FR2022310A1 (en) * | 1968-10-25 | 1970-07-31 | Huels Chemische Werke Ag | |
FR2021528A1 (en) * | 1968-10-25 | 1970-07-24 | Huels Chemische Werke Ag | |
DE1805190B2 (en) * | 1968-10-25 | 1976-12-23 | Chemische Werke Hüls AG, 4370 Mari | COATING AGENTS |
US3974115A (en) * | 1972-12-07 | 1976-08-10 | Schenectady Chemicals, Inc. | Water-soluble wire enamel |
US4535132A (en) * | 1983-12-12 | 1985-08-13 | Ppg Industries, Inc. | Thermosetting high solids solvent-based polyester polyol coating compositions |
US5097006A (en) * | 1990-11-21 | 1992-03-17 | U C B S.A. | Weatherable powder coating compositions |
-
1991
- 1991-12-23 US US07/813,221 patent/US5262494A/en not_active Expired - Lifetime
-
1992
- 1992-11-12 AU AU28288/92A patent/AU645445B2/en not_active Expired
- 1992-11-13 NZ NZ245115A patent/NZ245115A/en unknown
- 1992-11-18 CA CA 2083225 patent/CA2083225C/en not_active Expired - Lifetime
- 1992-11-24 EP EP19920310732 patent/EP0552540A1/en not_active Withdrawn
- 1992-12-02 FI FI925478A patent/FI925478A/en unknown
- 1992-12-07 NO NO92924718A patent/NO924718L/en unknown
- 1992-12-09 MX MX9207124A patent/MX9207124A/en unknown
- 1992-12-09 JP JP32918692A patent/JPH05310901A/en active Pending
Also Published As
Publication number | Publication date |
---|---|
EP0552540A1 (en) | 1993-07-28 |
AU2828892A (en) | 1993-07-29 |
AU645445B2 (en) | 1994-01-13 |
NO924718L (en) | 1993-06-24 |
US5262494A (en) | 1993-11-16 |
NZ245115A (en) | 1994-12-22 |
NO924718D0 (en) | 1992-12-07 |
JPH05310901A (en) | 1993-11-22 |
CA2083225A1 (en) | 1993-06-24 |
FI925478A0 (en) | 1992-12-02 |
FI925478A (en) | 1993-06-24 |
MX9207124A (en) | 1993-08-01 |
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