CA2261485A1 - Epoxy resin and hybrid powder coating compositions - Google Patents
Epoxy resin and hybrid powder coating compositions Download PDFInfo
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- CA2261485A1 CA2261485A1 CA002261485A CA2261485A CA2261485A1 CA 2261485 A1 CA2261485 A1 CA 2261485A1 CA 002261485 A CA002261485 A CA 002261485A CA 2261485 A CA2261485 A CA 2261485A CA 2261485 A1 CA2261485 A1 CA 2261485A1
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- polycarboxylic
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- 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
- C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
- C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
- C08G59/40—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the curing agents used
- C08G59/50—Amines
- C08G59/56—Amines together with other curing agents
- C08G59/58—Amines together with other curing agents with polycarboxylic acids or with anhydrides, halides, or low-molecular-weight esters thereof
-
- 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
- C09D163/00—Coating compositions based on epoxy resins; Coating compositions based on derivatives of epoxy resins
-
- 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
- C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
- C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
- C08G59/40—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the curing agents used
- C08G59/50—Amines
- C08G59/5093—Complexes of amines
-
- 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
- C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
- C09D5/03—Powdery paints
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Wood Science & Technology (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
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Abstract
Disclosed is an epoxy resin or hybrid resin-based powder coating composition, which comprises, as a hardener, a mixture of (a) a salt of a polycarboxylic acid (other than isophthalic acid, terephthalic acid and phthalic acid) and an amine or guanidine, such as the salt between pyromellitic acid and 2-phenylimidazoline, and (b) a polycarboxylic acid, preferably selected from the group consisting of cyanuric acid, ethylenediaminetetraacetic acid, isophthalic acid, terephthalic acid, 1,2,3,4-butanetetracarboxylic acid, trimellitic acid and trimesic acid. The coating composition is useful for producing a semi-gloss to matt coating layer.
Description
EPOXY RESIN AND HYBRID POWDER COATING COMPOSITIONS
The invention relates to epoxy (EP) resin or hybrid powder coating compositions.
DE-A 23 24 696 describes a process for producing matt coatings by curing epoxy resins with salts of aromatic poly-carboxylic acids, especially pyromellitic acid and cyclic amidines.
DE-A 44 00 931 describes salts of pyromel.litic acid and guanidines as hardeners for matt epoxy and hybrid coatings.
DE-A 44 03 225 describes salts of pyromellitic acid and tertiary amines which can be used to produce matt epoxy and hybrid coatings.
It is also known that only salts of cyclic amidines with trimell.itic and/or pyromellitic acid are suitable for producing matt EP powder coatings. In contrast, the corres-ponding salts of phthalic, isophthal.ic and terephthal.ic acid cure with EP resins to give glossy films.
An essential factor in the above prior art is that it is not the individual components but their reaction products, i. e., the salts, that are employed. Since the salts comprise pyromell.itic acid, hardeners of this type are relatively highly priced for high-quality epoxy and hybrid coatings. Another disadvantage is the yellowing of the coatings.
It is also known that by simultaneous use of the individual hardeners, namely the amine component and the pol.y-carboxylic acid, surfaces with the same degree of matting are O.Z. 5290 23443-671.
obtained as when the salt-form matt hardener consisting of the same individual components is employed. Since there is no need to prepare salts, these hardeners are less expensive.
However, surface texturing and poor physical properties are found in coatings produced with such hardeners, as well as poor reproducibility of the matt effect.
Such physical. mixtures of amine component and pol.y-carboxylic acid are described, for example, in EP-A 0 504 183.
Physical mixtures of salts and polycarboxylic acids were described for the first time in DE-A 44 00 929 and DE-A 44 03 129. The salts are reaction products of phthalic, isophthalic and terephthalic acids with guanidines or amines.
Pyromellitic and/or trimellitic acid are employed as the polycarboxyl.ic acids. The overtaking stability of coatings comprising such mixtures is disadvantageous.
To improve the yellowing resistance on overtaking of both glossy and matt EP powder coatings based on salts of cyclic amidines with aromatic polycarboxylic acids, DE 1.96 30 450 employs as its hardener component phosphoric acid salts in a mixture with the polycarboxylic acids. However, preparation of these complex hardeners is difficult. Fluctua-tions in the reaction conditions can lead to a different structure of the salt mixtures and hence to different coating results.
A major object of the present invention, therefore, is to provide a hardener essentially free from the disadvantages listed above and further provide a novel EP or hybrid powder O.Z. 5290 coating composition, which comprises the hardener, by a simple preparation process, and which is suitable for preparing semi-glossy to matt coatings with a high level. of quality.
Surprisingly, it has been found that, as the hardener component, a physical mixture of an aliphatic, cycloaliphatic, araliphatic or aromatic polycarboxyl.ic acid with a salt of an aliphatic, cycloaliphatic, aral.iphatic or aromatic poly-carboxylic acid and an amine is particularly effective for the above-mentioned purpose, provided that the pol.ycarboxylic acid of the salt is other than isophthalic acid, terephthalic acid and phthalic acid.
The present invention provides an epoxy resin or hybrid powder coating composition which comprises, as a hardener, a physical mixture of:
a) a salt of:
al) an aliphatic, cycloaliphatic, araliphatic or aromatic polycarboxylic acid other than isophthal.ic acid, terephthal.ic acid and phthalic acid, and a2) an amine of the formula:
(CH2 ) n Rl i iR3 R N~N
2 , o r HN / N
A) B) C) (wherein Rl, R2 and R3 are identical or different and are each 2,2,6,6-tetramethylpiperidin-4-yl or an aliphatic, cyclo-aliphatic, araliphatic or aromatic hydrocarbon radical. havingl -20 carbon atoms, in which one or more CH2 groups in the C chain O.Z. 5290 may be replaced by O, CH-OH or NR4 where R4 is Cl-6-alkyl or one or more terminal methyl. groups may be replaced by a dialkyl amino group having 1 to 6 carbon atoms in each alkyl. group or R1 and R2 together with the N atom to which they are attached form a ring in which one CH2 group may be replaced by O or NR4, Rl and R2 in the formula C) may be hydrogen or Rl, R2 and R3 in the formula A) are each -CH2-CH2- attached via a conjoint N
atom, and n is 3 - 11.) or a3) a guanidine compound of the formula:
R6 ~ N-- C-N~R8 R ~ NI \R9 \R5 D) (wherein R5, R6, R7, R8 and R9 independently of one another are identical or different and are an aliphatic, cycloaliphatic, araliphatic, aromatic hydrocarbon radical. having 1 - 9 C atoms or hydrogen, or R6 and R7 or R8 and R9 together with the N atom to which they are attached form a ring which may include an oxygen atom) and b) an aliphatic, cycloaliphatic, aral.iphatic or aromatic polycarboxylic acid, in a ratio a):b) of from 99:1 to 1:99.
The salts a) which can be employed in accordance with the invention comprise aliphatic, cycloal.iphatic, araliphatic or aromatic polycarboxylic acids. Isophthalic acid, terephthalic acid and phthalic acid are expressly excluded. In place of the acids, if desired, their anhydrides may be O.Z. 5290 employed for forming the salts (component al). Examples of the polycarboxylic acids are cyanuric acid, 2,2,4(2,4,4)-trimethyl-adipic acid, 1,2,3,4-butanetetracarboxylic acid, ethyl.ene-diaminetetraacetic acid, diethylenetriaminepentaacetic acid, nitrilotriacetic acid, hexahydrophthal.ic acid (i. e., cyclo-hexane-1,2-dicarboxyl.ic acid), hexahydroisophthalic acid (i. e., cyclohexane-1,3-dicarboxylic acid), hexahydroterephthalic acid (i. e., cyclohexane-1,4-dicarboxylic acid), pyromell.itic acid, trimellitic acid, trimesic acid, cycl.opentanetetracarboxyl.ic acid, citric acid, aconitic acid and 2,6-naphthalenedicarboxylic acid. When mixtures of the polycarboxylic acids are employed, any desired combinations are possible. One preferred group of the polycarboxylic acids are tri- and tetracarboxylic acids.
Another preferred group of the polycarboxyl.ic acids are aliphatic or cycl.oaliphatic polycarboxylic acids. Particularly preferred are tetracarboxylic acids, especially pyromellitic acid. Cyanuric acid may not be called as a polycarboxylic acid in a strict sense, but it can be used according to the invention just as a pol.ycarboxylic acid.
The salts of the polycarboxylic acids comprise, as their amine component a2) and/or a3), nitrogen compounds capable of forming salts, represented by the formulae A)-D).
Preferred are those amines of the formula C) in which R1 and R2 are each hydrogen, Cl-6-alkyl or phenyl. In the formula A), R1, R2 and R3 are preferably C1-20 alkyl, phenyl or cycl.ohexyl or two of them with the N atom to which they are attached form optionally substituted morphol.ine, piperazine or piperidine ring. Examples of specific compounds of the formulae A)-C) are O.Z. 5290 N,N-dimethylcyclohexylamine, N,N-dimethylaniline, N-methyl-morphol.ine, N,N'-dimethyl.piperazine, 2,2,6,6-tetramethyl-4-dimethylaminopiperidine, N,N-dimethyloctadecylamine, 1,8-diazabicyclo[5.4.0]undec-7-ene, N,N,N',N'-tetramethylhexa-methylenediamine, 1,4-diazabicyclo[2.2.2]octane, 2-phenyl-imidazoline, 2-methyl.imidazoline, 2,4-dimethylimidazoline and 2-ethyl.-4-methylimidazoline. Examples of specific compounds of the formula D) are tetramethylguanidine, tetramethylcyclo-hexyl.guanidine, N,N',N"-triphenylguanidine and N,N'-dicyclo-1.0 hexyl-4-morpholinecarboxamide. The basic N content of the salts may be generally 0.01 - 30 mmol/g and the carboxyl. group content may be generally 1 - 35 mmol/g.
The salts a) may be formed by reacting the pol.y-carboxylic acids or their anhydrides al) with 0.5 - 3 mols of the amines a2) or the guanidine compounds a2).
Components b) that are suitable for use are aliphatic, cycloaliphatic, aral.iphatic or aromatic polycarboxylic acids.
Examples that may be mentioned are cyanuric acid, 2,2,4(2,4,4)-trimethyladipic acid, 1,2,3,4-butanetetracarboxylic acid, 20 ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, nitril.otriacetic acid, hexahydrophthalic acid, hexahydro-isophthalic acid, hexahydroterephthalic acid, pyromellitic acid, trimel.litic acid, trimesic acid, cyclopentanetetra-carboxylic acid, citric acid and 2,6-naphthalenedicarboxylic acid. Isophthalic acid, terephthalic acid and phthalic acid may also be employed. When mixtures of the polycarboxylic acids are employed, any desired combinations are possible.
The invention relates to epoxy (EP) resin or hybrid powder coating compositions.
DE-A 23 24 696 describes a process for producing matt coatings by curing epoxy resins with salts of aromatic poly-carboxylic acids, especially pyromellitic acid and cyclic amidines.
DE-A 44 00 931 describes salts of pyromel.litic acid and guanidines as hardeners for matt epoxy and hybrid coatings.
DE-A 44 03 225 describes salts of pyromellitic acid and tertiary amines which can be used to produce matt epoxy and hybrid coatings.
It is also known that only salts of cyclic amidines with trimell.itic and/or pyromellitic acid are suitable for producing matt EP powder coatings. In contrast, the corres-ponding salts of phthalic, isophthal.ic and terephthal.ic acid cure with EP resins to give glossy films.
An essential factor in the above prior art is that it is not the individual components but their reaction products, i. e., the salts, that are employed. Since the salts comprise pyromell.itic acid, hardeners of this type are relatively highly priced for high-quality epoxy and hybrid coatings. Another disadvantage is the yellowing of the coatings.
It is also known that by simultaneous use of the individual hardeners, namely the amine component and the pol.y-carboxylic acid, surfaces with the same degree of matting are O.Z. 5290 23443-671.
obtained as when the salt-form matt hardener consisting of the same individual components is employed. Since there is no need to prepare salts, these hardeners are less expensive.
However, surface texturing and poor physical properties are found in coatings produced with such hardeners, as well as poor reproducibility of the matt effect.
Such physical. mixtures of amine component and pol.y-carboxylic acid are described, for example, in EP-A 0 504 183.
Physical mixtures of salts and polycarboxylic acids were described for the first time in DE-A 44 00 929 and DE-A 44 03 129. The salts are reaction products of phthalic, isophthalic and terephthalic acids with guanidines or amines.
Pyromellitic and/or trimellitic acid are employed as the polycarboxyl.ic acids. The overtaking stability of coatings comprising such mixtures is disadvantageous.
To improve the yellowing resistance on overtaking of both glossy and matt EP powder coatings based on salts of cyclic amidines with aromatic polycarboxylic acids, DE 1.96 30 450 employs as its hardener component phosphoric acid salts in a mixture with the polycarboxylic acids. However, preparation of these complex hardeners is difficult. Fluctua-tions in the reaction conditions can lead to a different structure of the salt mixtures and hence to different coating results.
A major object of the present invention, therefore, is to provide a hardener essentially free from the disadvantages listed above and further provide a novel EP or hybrid powder O.Z. 5290 coating composition, which comprises the hardener, by a simple preparation process, and which is suitable for preparing semi-glossy to matt coatings with a high level. of quality.
Surprisingly, it has been found that, as the hardener component, a physical mixture of an aliphatic, cycloaliphatic, araliphatic or aromatic polycarboxyl.ic acid with a salt of an aliphatic, cycloaliphatic, aral.iphatic or aromatic poly-carboxylic acid and an amine is particularly effective for the above-mentioned purpose, provided that the pol.ycarboxylic acid of the salt is other than isophthalic acid, terephthalic acid and phthalic acid.
The present invention provides an epoxy resin or hybrid powder coating composition which comprises, as a hardener, a physical mixture of:
a) a salt of:
al) an aliphatic, cycloaliphatic, araliphatic or aromatic polycarboxylic acid other than isophthal.ic acid, terephthal.ic acid and phthalic acid, and a2) an amine of the formula:
(CH2 ) n Rl i iR3 R N~N
2 , o r HN / N
A) B) C) (wherein Rl, R2 and R3 are identical or different and are each 2,2,6,6-tetramethylpiperidin-4-yl or an aliphatic, cyclo-aliphatic, araliphatic or aromatic hydrocarbon radical. havingl -20 carbon atoms, in which one or more CH2 groups in the C chain O.Z. 5290 may be replaced by O, CH-OH or NR4 where R4 is Cl-6-alkyl or one or more terminal methyl. groups may be replaced by a dialkyl amino group having 1 to 6 carbon atoms in each alkyl. group or R1 and R2 together with the N atom to which they are attached form a ring in which one CH2 group may be replaced by O or NR4, Rl and R2 in the formula C) may be hydrogen or Rl, R2 and R3 in the formula A) are each -CH2-CH2- attached via a conjoint N
atom, and n is 3 - 11.) or a3) a guanidine compound of the formula:
R6 ~ N-- C-N~R8 R ~ NI \R9 \R5 D) (wherein R5, R6, R7, R8 and R9 independently of one another are identical or different and are an aliphatic, cycloaliphatic, araliphatic, aromatic hydrocarbon radical. having 1 - 9 C atoms or hydrogen, or R6 and R7 or R8 and R9 together with the N atom to which they are attached form a ring which may include an oxygen atom) and b) an aliphatic, cycloaliphatic, aral.iphatic or aromatic polycarboxylic acid, in a ratio a):b) of from 99:1 to 1:99.
The salts a) which can be employed in accordance with the invention comprise aliphatic, cycloal.iphatic, araliphatic or aromatic polycarboxylic acids. Isophthalic acid, terephthalic acid and phthalic acid are expressly excluded. In place of the acids, if desired, their anhydrides may be O.Z. 5290 employed for forming the salts (component al). Examples of the polycarboxylic acids are cyanuric acid, 2,2,4(2,4,4)-trimethyl-adipic acid, 1,2,3,4-butanetetracarboxylic acid, ethyl.ene-diaminetetraacetic acid, diethylenetriaminepentaacetic acid, nitrilotriacetic acid, hexahydrophthal.ic acid (i. e., cyclo-hexane-1,2-dicarboxyl.ic acid), hexahydroisophthalic acid (i. e., cyclohexane-1,3-dicarboxylic acid), hexahydroterephthalic acid (i. e., cyclohexane-1,4-dicarboxylic acid), pyromell.itic acid, trimellitic acid, trimesic acid, cycl.opentanetetracarboxyl.ic acid, citric acid, aconitic acid and 2,6-naphthalenedicarboxylic acid. When mixtures of the polycarboxylic acids are employed, any desired combinations are possible. One preferred group of the polycarboxylic acids are tri- and tetracarboxylic acids.
Another preferred group of the polycarboxyl.ic acids are aliphatic or cycl.oaliphatic polycarboxylic acids. Particularly preferred are tetracarboxylic acids, especially pyromellitic acid. Cyanuric acid may not be called as a polycarboxylic acid in a strict sense, but it can be used according to the invention just as a pol.ycarboxylic acid.
The salts of the polycarboxylic acids comprise, as their amine component a2) and/or a3), nitrogen compounds capable of forming salts, represented by the formulae A)-D).
Preferred are those amines of the formula C) in which R1 and R2 are each hydrogen, Cl-6-alkyl or phenyl. In the formula A), R1, R2 and R3 are preferably C1-20 alkyl, phenyl or cycl.ohexyl or two of them with the N atom to which they are attached form optionally substituted morphol.ine, piperazine or piperidine ring. Examples of specific compounds of the formulae A)-C) are O.Z. 5290 N,N-dimethylcyclohexylamine, N,N-dimethylaniline, N-methyl-morphol.ine, N,N'-dimethyl.piperazine, 2,2,6,6-tetramethyl-4-dimethylaminopiperidine, N,N-dimethyloctadecylamine, 1,8-diazabicyclo[5.4.0]undec-7-ene, N,N,N',N'-tetramethylhexa-methylenediamine, 1,4-diazabicyclo[2.2.2]octane, 2-phenyl-imidazoline, 2-methyl.imidazoline, 2,4-dimethylimidazoline and 2-ethyl.-4-methylimidazoline. Examples of specific compounds of the formula D) are tetramethylguanidine, tetramethylcyclo-hexyl.guanidine, N,N',N"-triphenylguanidine and N,N'-dicyclo-1.0 hexyl-4-morpholinecarboxamide. The basic N content of the salts may be generally 0.01 - 30 mmol/g and the carboxyl. group content may be generally 1 - 35 mmol/g.
The salts a) may be formed by reacting the pol.y-carboxylic acids or their anhydrides al) with 0.5 - 3 mols of the amines a2) or the guanidine compounds a2).
Components b) that are suitable for use are aliphatic, cycloaliphatic, aral.iphatic or aromatic polycarboxylic acids.
Examples that may be mentioned are cyanuric acid, 2,2,4(2,4,4)-trimethyladipic acid, 1,2,3,4-butanetetracarboxylic acid, 20 ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, nitril.otriacetic acid, hexahydrophthalic acid, hexahydro-isophthalic acid, hexahydroterephthalic acid, pyromellitic acid, trimel.litic acid, trimesic acid, cyclopentanetetra-carboxylic acid, citric acid and 2,6-naphthalenedicarboxylic acid. Isophthalic acid, terephthalic acid and phthalic acid may also be employed. When mixtures of the polycarboxylic acids are employed, any desired combinations are possible.
O.Z. 5290 The hardeners of the invention comprising components a) and b) may be prepared in two stages, where in the first stage the salt is formed in a solvent and when this process has ended the solvent is removed. In a second step, one or more aliphatic, cycloaliphatic, araliphatic or aromatic poly-carboxylic acids are physically admixed.
Some of the salts a) are known. In addition, they are not a subject of the invention. They are prepared in a known manner, for example, by adding the amine/guanidine 1.0 component a2/a3, in portions, to the pol.ycarboxylic acid in a boiling solution in water or ethanol. After the end of this addition, heating is continued for about one hour or more.
Subsequently, the solvent is removed by distillation. For quantitative removal of the solvent the reaction mixture is dried in a vacuum drying oven at 60°C for about 1.0 h. Then the aliphatic, cycl.oal.iphatic, araliphatic or aromatic poly-carboxylic acids are admixed. The salts a) are composed of 1 mol of the polycarboxylic acid and 0.5 - 3 mol. of the compounds A)-D). The composition of the hardener mixture a) and b) of 20 the invention consists of 99 - l.s, preferably 90 - l0a by weight of the salt a) and 1 - 99~, preferably 10 - 90~ by weight of the polycarboxylic acid b).
The hardener mixture a) and b) of the invention is combined with epoxy resins or hybrid resins. Hybrids are carboxyl-functional polyester resins that have been mixed with epoxy resins.
To prepare the coating compositions of the invention, the hardeners are employed in amounts effective to work as - 7 _ O.Z. 5290 hardeners, for example, 2 - 14% by weight based on the sum of the starting resins. The polyepoxy resins used are well.-known in the art and are generally solid, resinous substances which melt in the range 60 - 150°C, preferably 70 - 110°C, and contain on average more than one 1.,2-epoxide group per molecule. In principle, suitable compounds are all those containing more than one 1.,2-epoxide group per molecule.
Examples are polyepoxides, such as polyglycidyl ethers of aromatic or aliphatic compounds containing two or more active hydrogen atoms. These include resorcinol., hydroquinone, pyrocatechol, bisphenol A, bisphenol. F, glycerol., pentaerythri-tol, mannitol, sorbitol and trimethylolpropane. Preference is given, however; to customary commercial EP resins, as are obtained by reacting bisphenol. A or bisphenol F with epichloro-hydrin. Very particular preference is given to EP resins based on the reaction between bisphenol A and epichlorohydrin and having an EP equivalent weight of 400 - 3,000, preferably 800 -1,000.
The carboxyl-functional polyester resins are polyester polycarboxylic acids which are prepared from polyols and polycarboxylic acids or derivatives thereof. The melting point of these acidic polyesters lies generally within the range of 60 - 160°C, preferably 80 - 120°C; their acid number varies from 10 - 150 mg of KOH/g, preferably 30 - 60 mg of KOH/g. The OH numbers are normally below 10 mg of KOH/g.
The polyester polycarboxylic acids that are to be employed may be prepared using polycarboxylic acids, such as oxalic, adipic, 2,2,4(2,4,4)-trimethyladipic, azelaic, sebacic, _ g -O.Z. 5290 decanedicarboxylic, dodecanedicarboxylic, fumaric, phthalic, isophthalic, terephthalic, trimel.litic and pyromel.litic acid, for example. Examples of pol.yols used for the acidic poly-esters are as follows: ethylene glycol, 1,2- and 1,3-propane-diol, 1,2-, 1,3-, 1-4- and 2,3-butanediol., 1,5-pentanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,12-dodecanediol, 2,2,4(2,4,4)-trimethyl.-1,6-hexanediol, trimethyl.olpropane, glycerol, pentaerythritol, 1.,4-bishydroxymethylcyclohexane, cyclohexane-1,4-diol, diethylene glycol, triethylene glycol and dipropylene glycol.. It is of course also possible to react hydroxyl.-containing polyesters, which are prepared by known methods from polycarboxylic acids and polyols, with poly-carboxylic acids and/or polycarboxylic anhydrides to give the polyester polycarboxylic acids.
In the case of the exclusive use of the customary commercial EP resins based on bisphenol A (+ epichlorohydrin), the amount of the hardener is usually 2 - 1.4% by weight. In the case where mixtures of the epoxy resins and the polyester pol.ycarboxylic acids are used, the proportion is guided by the acid number of the carboxyl polyester. For example, at an acid number of 30 - 50 mg of KOH/g, the weight ratio of EP
resin to carboxyl polyester is usually from 60 . 40 to 80 . 20, preferably 70 . 30. The amount of the hardener mixture a) + b) in these EP resin/carboxyl polyester mixtures is usually 2 - 14~ by weight. Before or after they are mixed, the hardener components are preferably ground to an average particle size of less than 100 um, preferably less than 40 um.
O.Z. 5290 To prepare the powder coating material, the binders may first of al.l be mixed with a leveling agent, pigment and/or filler and with W stabilizers and antioxidants and the mixture may be homogenized in an extruder at about 100°C. After the extruded mass has cooled to room temperature, it may be ground into a powder coating material. whose average particle size is normally about 30 - 100 um, preferably 40 - 80 um.
The coating compositions of the invention are suit-able for preparing coating materials, especially for powder 1.0 coatings having semi-glossy to matt surfaces. The amounts of the individual. powder coating binder components can be varied extensively.
The application of powder coatings based on the coating compositions of the invention to appropriate substrates can take place by the known methods, such as, for example, by electrostatic powder spraying, fluidized-bed sintering or electrostatic fluidized-bed sintering. Following the applica-tion of the powder coating by one of these techniques, the coated substrates are cured by heating at temperatures of 1.50 -20 220°C. The curing often takes about 30 - 8 minutes. The coating films produced in this way are notable for very good leveling, good to very good mechanical properties and a matt surface, it being possible to adjust the degree of gloss as desired within a wide range.
The examples which follow are intended to elucidate the invention further.
O.Z. 5290 A Preparing the hardener mixtures employed in the process of the invention General preparation procedure The amine (a2 and/or a3) is added in portions to the pol.ycarboxyl.ic acid al), which is heated with from 6 to 10 times the amount of ethanol and/or water to the boiling point of the solvent. After the end of the addition of amine, heating is continued for about 1 h more. Then the solvent is removed, generally by distillation. For quantitative removal.
of the solvent the reaction product is subsequently after-treated at about 60°C in a vacuum drying oven. The salt a) is then physically mixed with the polycarboxyl.ic acid b).
The hardeners listed in Table 1 below were prepared by the general. preparation procedure.
O.Z. 5290 Table 1 : Hardener mixtures ExampleHardener Characteristic mixture data com ition A Salt e) PolycyrboxylicN contentCOON
and b) content PolyutboxylfeAminel9uanidine( 3 by weightJmmoll9JJmmoUpJ
geld (!i based (! by weightlby weight) on salts 1 a) 16.5 PMA 53.5 PI 20 CYA 10.50 7.58 1 b) 46.5 PMA 53.5 PI 51 CYA 15.51 13.73 1 c 46.5 PMA 53.5 PI 63 CYA 17.33 15.97 2 a) 63.5 PMA 36.5 PI 10 CYA 6.82 9.07 2 b) 63.5 PMA 36.5 PI 20 CYA 8.65 10.64 2 c 63.5 PMA 36.5 PI 50 CYA 14.12 15.77 3 a) 46.5 PMA 53.5 PI 10 EDTA 7.27 4.66 3 b) 46.5 PMA 53.5 Pt 40 EDTA 7.13 7.67 3 c 46.5 PMA 53.5 PI 60 EDTA 7.03 9.68 4 s) 63.5 PMA 36.5 PI 10 EDTA 5.18 8.11 4 b) 63.5 PMA 36.5 PI 20 EOTA 5.37 8.73 4 c) 63.5 PMA 36.5 PI 30 EDTA 5.55 9.35 5 a) 46.5 PAAA 53.5 PI t 0 IA 6.59 4.50 5 b) 46.5 PMA 53.5 PI 30 IA 5.12 6.17 5 c! 46.5 PMA 53.5 Pt 80 IA 1 46 10.36 6 a) 63.5 PMA 36.5 PI 10 IA 4.50 7.95 6 b 63.5 PMA 36.5 PI 50 IA 2.50 9.77 7 a) 46.5 PMA 53.5 PI 20 TA 5.86 5.34 7 b 46.5 PMA 53.5 PI 55 TA 3.29 8.27 8 a) 63.5 PMA 36.5 PI 20 TA 4.00 8.40 8 b1 63.5 PMA 36.5 PI 50 TA 2.50 9.T7 9 a) 46.5 PMA 53.5 PI 10 BTA 6.59 5.0 9 b d6.5 PMA 53.5 PI 20 BTA 5.86 6.34 10 al 63.5 PMA 36.5 PI 10 ATA 4.50 8.45 10 b) 63.5 PMA 36.5 PI 20 8TA 4.00 9.41 10 c 63.5 PMA 36.5 PI 40 BTA 3.00 11.33 11 a) 46.5 PMA 53.5 P) 10 TMA 6.59 4 72 11 b) d6.5 PMA 53.5 PI 20 TMA 5.86 5 78 11 c) 46.5 PMA 53.5 PI 40 TMA 4.39 7 91 1 i 46.5 PMA 53.5 PI 70 TMA 2.20 11 09 12 a) 63.5 PMA 36.5 PI 10 TMA 4.50 8.17 12 b! 63.5 PMA 36.5 PI 50 TMA 2.50 10.89 13 a) 46.5 PMA 53.5 PI 10 TMSA 6.59 4.72 13 b) 46.5 PMA 53.5 PI 40 TMSA 4 39 7.91 13 c 46.5 PMA 53.5 PI 60 TMSA 2.93 10.03 I
I 14 63.5 PMA 36.5 P1 10 TMSA 4.50 8.17 a) 14 b) 63.5 PMA 36.5 PI 40 TMSA 3.00 10.21 14 c 63.5 PMA 36.5 P1 60 TMSA 2.00 11.56 O.Z. 5290 Key:
BTA: 1,2,3,4-butanetetracarboxylic acid CYA: cyanuric acid IA: isophthalic acid PI: 2-phenylimidazoline PMA: pyromellitic acid TMA: trimellitic acid TMSA: trimesic acid TA: terephthalic acid 1 o EDTA: ethylenediaminetetraacetic acid B Epox~,r resin Bisphenol A was the basis of the epoxy resin compound employed in the Use Examples. It has the following characteristic data:
Table 2: Characteristic data of the epoxy resin Example B 1 Characteristic data E uivalent wei ht 900 - 1000 j E oxide value 0.1 - 0.111 H drox I value 0.34 Meltin ran a 96 - 104C
C Epoxy resin powder coating composition To prepare the epoxy resin powder coating compositions of the invention the ground starting materials - hardener, epoxy resin and leveling agent masterbatch ( log by weight of leveling agent based on polymeric butyl 2 o acrylates is homogenized in the melt with the epoxy resins and the melt is O.Z. 5290 comminuted after it has so~dified) - were intimately mixed in an edge runner mill with the white pigment (Ti02) and the mixture was then homogenized in an extruder at from 90 to 110°C. After cooling, the extrudate was fractionated and ground in a pin mill to a particle size < 100 Nm (Coatings Examples).
The powder prepared as described above was applied to degreased and optionally pretreated steel panels using an electrostatic powder spraying unit at 60 kV and the panels were baked in a laboratory drying oven operating with air circulation.
The abbreviations in the tables below have the following meanings:
1o LT - Layer thickness in Nm CH - Crosshatch test (DIN 53 151 ) GG fi0°Q = Gardner gloss (ASTM-D 5233) EI - Erichsen indentation in mm (DIN 53 15fi) BI dir. - Ball impact direct in inch'Ib YI - Yellowness index The coating formulations were calculated in accordance with the following scheme:
by weight EP = epoxide B - C = EP B = % by weight of binder 20 C = % by weight of crosslinker B = 100 - A A = % by weight of adjuvants X40% by weight white pigment (Ti02 ) , 0 . 5~
by weight leveling agent]
O.Z. 5290 Table 3: Coatings Examples ExampleCrosslinkarCunn9 Mechanical ac- data cording to C ~' by 'CJmin LT CH GG 60'GEI BI YI
weight) dir.
1 3.5 A 200112 48 - 0 18 - 8.0-9.5>80 7.2 t a) 57 19 2 3.5 A 200H 60 - 0 19 - 9.0 50 8.0 t b) 2 76 20 3 3.5 A 200112 75 - 0 24 - 9.5 50 9.1 1 c 85 26 4 5.0 A 200115 69 - 1 9 7.0 >80 13.8 2 a) 71 5.0 A 200/15 89 - 0 12 - 7.0 >80 132 2 b) 104 13 6 5.0 A 200/15 64 - 0 25 - 8.5-9.5>80 8.9 2 a 82 26 7 3.5 A 200/15 76 - 1 15 - 7.5-9.5>80 18.4 3 a) 89 16 8 3.5 A 200!15 61 - 1 10 6.5-B.040 17.2 3 b 78 9 5.OA4a) 200115 84-99 0-1 6-7 7.0 >80 17.9 5.0 A 200/15 48 - 1 - 7 - 7.5 >80 15~
4 b) 61 2 8 11 5.0 A 20dt 53 - 1 7 - 7.0 >80 17.1 4 c 5 72 8 12 3.5 A 200/15 67 - 1 17 - 9.0 >80 17.4 5 a) 92 18 13 3.5 A 200115 57 - 0 19 8.5-9.060 14.8 5 b) 72 14 3.5 A 200!25 63 - 0 31 - 8.5 60 13 2 5 c) 77 32 t5 5.OA6a) 200115 59-72 0 5 8.0 >BO 15.1 16 5 0 A 200!15 77 - 1 25 - 9.0 >80 13.0 6 b) 103 26 17 3.5 A 200115 76 - 1 19 8Ø5 >80 12.8 7 a) 65 18 3.SA7b 200125 75-91 0-1 16-17 9.0 60 12.7 19 5.0 A 200115 10 - 1 8 8.0-0.5>80 11.6 8 a) 55 5.0 A 200115 50 - 1 31 - 9.0 >80 11.0 8 b 62 34 21 3.5 A 200115 76 - 0 14 8.0 60 18.0 9 a) 90 22 3.5 A 20W15 82 - 0 12 6.5-7.060 18.4 9 b 92 1 13 23 5.0 A 200/15 57 - 0 - 6 - 7.5-0.5>80 13.6 10 a) 64 1 7 24 5.0 A 200!15 78 - 1 7 - 6.5-7.0>80 16.2 10 b) 82 9 5.0 A 200115 36 . t 12 - 7.5-8.0>80 13.
10 c) 5p 15 t 26 3.5 A 200/15 47 - 0 16 - 8.0-8.5>80 13.9 11 a) 62 17 27 3.5 A 200115 67 - 1 14 - 6.0 >80 14.7 11 b) 80 15 28 3.5 A 200115 77 - 0 20 7.5 60 10.6 11 c 88 29 5.0 A 200/15 44 - 1 6 8.0 >80 12.5 12 a) 58 5 0 A 200/15 48 - 1 30 - 8.5-9.0>80 10.1 12 b) 68 31 31 3.5 A 200/15 58 - 0 - 17 8.0-8.580 16.3 13 a) 81 1 32 3.5 A 200125 72 - 1 11 4.0-7.040 15.0 13 c) 92 33 5.0 A 200115 77 - 0 5 7.0-7.5>80 14.5 14 a) 91 34 5.0 A 200r25 90 - 0 8 6.0 >80 13.1 14 b 105 1 D Carboxyl-containing pol~resters To prepare a hybrid powder coating composition the carboxyl-containing polyesters described below were employed, having the following characteri-O.Z. 5290 stic data:
Table 4: Characteristic data of the acidic polyester Example D 1 Characteristic data Acid number 30 mg of KOH/
Meltin ran a 78 - 81 C
Glass transition tem erature 64 C
E Hybrid powder coating examples The preparation of the raw materials, and also the preparation and ap-plication of the coatings, is as in C. The hybrid powder coatings comprise epoxy resin and polyesterpolycarboxylic acids in a ratio of 75 : 25, 40% by mass white pigment (Ti02) and 1 % by mass leveling agent.
Some of the salts a) are known. In addition, they are not a subject of the invention. They are prepared in a known manner, for example, by adding the amine/guanidine 1.0 component a2/a3, in portions, to the pol.ycarboxylic acid in a boiling solution in water or ethanol. After the end of this addition, heating is continued for about one hour or more.
Subsequently, the solvent is removed by distillation. For quantitative removal of the solvent the reaction mixture is dried in a vacuum drying oven at 60°C for about 1.0 h. Then the aliphatic, cycl.oal.iphatic, araliphatic or aromatic poly-carboxylic acids are admixed. The salts a) are composed of 1 mol of the polycarboxylic acid and 0.5 - 3 mol. of the compounds A)-D). The composition of the hardener mixture a) and b) of 20 the invention consists of 99 - l.s, preferably 90 - l0a by weight of the salt a) and 1 - 99~, preferably 10 - 90~ by weight of the polycarboxylic acid b).
The hardener mixture a) and b) of the invention is combined with epoxy resins or hybrid resins. Hybrids are carboxyl-functional polyester resins that have been mixed with epoxy resins.
To prepare the coating compositions of the invention, the hardeners are employed in amounts effective to work as - 7 _ O.Z. 5290 hardeners, for example, 2 - 14% by weight based on the sum of the starting resins. The polyepoxy resins used are well.-known in the art and are generally solid, resinous substances which melt in the range 60 - 150°C, preferably 70 - 110°C, and contain on average more than one 1.,2-epoxide group per molecule. In principle, suitable compounds are all those containing more than one 1.,2-epoxide group per molecule.
Examples are polyepoxides, such as polyglycidyl ethers of aromatic or aliphatic compounds containing two or more active hydrogen atoms. These include resorcinol., hydroquinone, pyrocatechol, bisphenol A, bisphenol. F, glycerol., pentaerythri-tol, mannitol, sorbitol and trimethylolpropane. Preference is given, however; to customary commercial EP resins, as are obtained by reacting bisphenol. A or bisphenol F with epichloro-hydrin. Very particular preference is given to EP resins based on the reaction between bisphenol A and epichlorohydrin and having an EP equivalent weight of 400 - 3,000, preferably 800 -1,000.
The carboxyl-functional polyester resins are polyester polycarboxylic acids which are prepared from polyols and polycarboxylic acids or derivatives thereof. The melting point of these acidic polyesters lies generally within the range of 60 - 160°C, preferably 80 - 120°C; their acid number varies from 10 - 150 mg of KOH/g, preferably 30 - 60 mg of KOH/g. The OH numbers are normally below 10 mg of KOH/g.
The polyester polycarboxylic acids that are to be employed may be prepared using polycarboxylic acids, such as oxalic, adipic, 2,2,4(2,4,4)-trimethyladipic, azelaic, sebacic, _ g -O.Z. 5290 decanedicarboxylic, dodecanedicarboxylic, fumaric, phthalic, isophthalic, terephthalic, trimel.litic and pyromel.litic acid, for example. Examples of pol.yols used for the acidic poly-esters are as follows: ethylene glycol, 1,2- and 1,3-propane-diol, 1,2-, 1,3-, 1-4- and 2,3-butanediol., 1,5-pentanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,12-dodecanediol, 2,2,4(2,4,4)-trimethyl.-1,6-hexanediol, trimethyl.olpropane, glycerol, pentaerythritol, 1.,4-bishydroxymethylcyclohexane, cyclohexane-1,4-diol, diethylene glycol, triethylene glycol and dipropylene glycol.. It is of course also possible to react hydroxyl.-containing polyesters, which are prepared by known methods from polycarboxylic acids and polyols, with poly-carboxylic acids and/or polycarboxylic anhydrides to give the polyester polycarboxylic acids.
In the case of the exclusive use of the customary commercial EP resins based on bisphenol A (+ epichlorohydrin), the amount of the hardener is usually 2 - 1.4% by weight. In the case where mixtures of the epoxy resins and the polyester pol.ycarboxylic acids are used, the proportion is guided by the acid number of the carboxyl polyester. For example, at an acid number of 30 - 50 mg of KOH/g, the weight ratio of EP
resin to carboxyl polyester is usually from 60 . 40 to 80 . 20, preferably 70 . 30. The amount of the hardener mixture a) + b) in these EP resin/carboxyl polyester mixtures is usually 2 - 14~ by weight. Before or after they are mixed, the hardener components are preferably ground to an average particle size of less than 100 um, preferably less than 40 um.
O.Z. 5290 To prepare the powder coating material, the binders may first of al.l be mixed with a leveling agent, pigment and/or filler and with W stabilizers and antioxidants and the mixture may be homogenized in an extruder at about 100°C. After the extruded mass has cooled to room temperature, it may be ground into a powder coating material. whose average particle size is normally about 30 - 100 um, preferably 40 - 80 um.
The coating compositions of the invention are suit-able for preparing coating materials, especially for powder 1.0 coatings having semi-glossy to matt surfaces. The amounts of the individual. powder coating binder components can be varied extensively.
The application of powder coatings based on the coating compositions of the invention to appropriate substrates can take place by the known methods, such as, for example, by electrostatic powder spraying, fluidized-bed sintering or electrostatic fluidized-bed sintering. Following the applica-tion of the powder coating by one of these techniques, the coated substrates are cured by heating at temperatures of 1.50 -20 220°C. The curing often takes about 30 - 8 minutes. The coating films produced in this way are notable for very good leveling, good to very good mechanical properties and a matt surface, it being possible to adjust the degree of gloss as desired within a wide range.
The examples which follow are intended to elucidate the invention further.
O.Z. 5290 A Preparing the hardener mixtures employed in the process of the invention General preparation procedure The amine (a2 and/or a3) is added in portions to the pol.ycarboxyl.ic acid al), which is heated with from 6 to 10 times the amount of ethanol and/or water to the boiling point of the solvent. After the end of the addition of amine, heating is continued for about 1 h more. Then the solvent is removed, generally by distillation. For quantitative removal.
of the solvent the reaction product is subsequently after-treated at about 60°C in a vacuum drying oven. The salt a) is then physically mixed with the polycarboxyl.ic acid b).
The hardeners listed in Table 1 below were prepared by the general. preparation procedure.
O.Z. 5290 Table 1 : Hardener mixtures ExampleHardener Characteristic mixture data com ition A Salt e) PolycyrboxylicN contentCOON
and b) content PolyutboxylfeAminel9uanidine( 3 by weightJmmoll9JJmmoUpJ
geld (!i based (! by weightlby weight) on salts 1 a) 16.5 PMA 53.5 PI 20 CYA 10.50 7.58 1 b) 46.5 PMA 53.5 PI 51 CYA 15.51 13.73 1 c 46.5 PMA 53.5 PI 63 CYA 17.33 15.97 2 a) 63.5 PMA 36.5 PI 10 CYA 6.82 9.07 2 b) 63.5 PMA 36.5 PI 20 CYA 8.65 10.64 2 c 63.5 PMA 36.5 PI 50 CYA 14.12 15.77 3 a) 46.5 PMA 53.5 PI 10 EDTA 7.27 4.66 3 b) 46.5 PMA 53.5 Pt 40 EDTA 7.13 7.67 3 c 46.5 PMA 53.5 PI 60 EDTA 7.03 9.68 4 s) 63.5 PMA 36.5 PI 10 EDTA 5.18 8.11 4 b) 63.5 PMA 36.5 PI 20 EOTA 5.37 8.73 4 c) 63.5 PMA 36.5 PI 30 EDTA 5.55 9.35 5 a) 46.5 PAAA 53.5 PI t 0 IA 6.59 4.50 5 b) 46.5 PMA 53.5 PI 30 IA 5.12 6.17 5 c! 46.5 PMA 53.5 Pt 80 IA 1 46 10.36 6 a) 63.5 PMA 36.5 PI 10 IA 4.50 7.95 6 b 63.5 PMA 36.5 PI 50 IA 2.50 9.77 7 a) 46.5 PMA 53.5 PI 20 TA 5.86 5.34 7 b 46.5 PMA 53.5 PI 55 TA 3.29 8.27 8 a) 63.5 PMA 36.5 PI 20 TA 4.00 8.40 8 b1 63.5 PMA 36.5 PI 50 TA 2.50 9.T7 9 a) 46.5 PMA 53.5 PI 10 BTA 6.59 5.0 9 b d6.5 PMA 53.5 PI 20 BTA 5.86 6.34 10 al 63.5 PMA 36.5 PI 10 ATA 4.50 8.45 10 b) 63.5 PMA 36.5 PI 20 8TA 4.00 9.41 10 c 63.5 PMA 36.5 PI 40 BTA 3.00 11.33 11 a) 46.5 PMA 53.5 P) 10 TMA 6.59 4 72 11 b) d6.5 PMA 53.5 PI 20 TMA 5.86 5 78 11 c) 46.5 PMA 53.5 PI 40 TMA 4.39 7 91 1 i 46.5 PMA 53.5 PI 70 TMA 2.20 11 09 12 a) 63.5 PMA 36.5 PI 10 TMA 4.50 8.17 12 b! 63.5 PMA 36.5 PI 50 TMA 2.50 10.89 13 a) 46.5 PMA 53.5 PI 10 TMSA 6.59 4.72 13 b) 46.5 PMA 53.5 PI 40 TMSA 4 39 7.91 13 c 46.5 PMA 53.5 PI 60 TMSA 2.93 10.03 I
I 14 63.5 PMA 36.5 P1 10 TMSA 4.50 8.17 a) 14 b) 63.5 PMA 36.5 PI 40 TMSA 3.00 10.21 14 c 63.5 PMA 36.5 P1 60 TMSA 2.00 11.56 O.Z. 5290 Key:
BTA: 1,2,3,4-butanetetracarboxylic acid CYA: cyanuric acid IA: isophthalic acid PI: 2-phenylimidazoline PMA: pyromellitic acid TMA: trimellitic acid TMSA: trimesic acid TA: terephthalic acid 1 o EDTA: ethylenediaminetetraacetic acid B Epox~,r resin Bisphenol A was the basis of the epoxy resin compound employed in the Use Examples. It has the following characteristic data:
Table 2: Characteristic data of the epoxy resin Example B 1 Characteristic data E uivalent wei ht 900 - 1000 j E oxide value 0.1 - 0.111 H drox I value 0.34 Meltin ran a 96 - 104C
C Epoxy resin powder coating composition To prepare the epoxy resin powder coating compositions of the invention the ground starting materials - hardener, epoxy resin and leveling agent masterbatch ( log by weight of leveling agent based on polymeric butyl 2 o acrylates is homogenized in the melt with the epoxy resins and the melt is O.Z. 5290 comminuted after it has so~dified) - were intimately mixed in an edge runner mill with the white pigment (Ti02) and the mixture was then homogenized in an extruder at from 90 to 110°C. After cooling, the extrudate was fractionated and ground in a pin mill to a particle size < 100 Nm (Coatings Examples).
The powder prepared as described above was applied to degreased and optionally pretreated steel panels using an electrostatic powder spraying unit at 60 kV and the panels were baked in a laboratory drying oven operating with air circulation.
The abbreviations in the tables below have the following meanings:
1o LT - Layer thickness in Nm CH - Crosshatch test (DIN 53 151 ) GG fi0°Q = Gardner gloss (ASTM-D 5233) EI - Erichsen indentation in mm (DIN 53 15fi) BI dir. - Ball impact direct in inch'Ib YI - Yellowness index The coating formulations were calculated in accordance with the following scheme:
by weight EP = epoxide B - C = EP B = % by weight of binder 20 C = % by weight of crosslinker B = 100 - A A = % by weight of adjuvants X40% by weight white pigment (Ti02 ) , 0 . 5~
by weight leveling agent]
O.Z. 5290 Table 3: Coatings Examples ExampleCrosslinkarCunn9 Mechanical ac- data cording to C ~' by 'CJmin LT CH GG 60'GEI BI YI
weight) dir.
1 3.5 A 200112 48 - 0 18 - 8.0-9.5>80 7.2 t a) 57 19 2 3.5 A 200H 60 - 0 19 - 9.0 50 8.0 t b) 2 76 20 3 3.5 A 200112 75 - 0 24 - 9.5 50 9.1 1 c 85 26 4 5.0 A 200115 69 - 1 9 7.0 >80 13.8 2 a) 71 5.0 A 200/15 89 - 0 12 - 7.0 >80 132 2 b) 104 13 6 5.0 A 200/15 64 - 0 25 - 8.5-9.5>80 8.9 2 a 82 26 7 3.5 A 200/15 76 - 1 15 - 7.5-9.5>80 18.4 3 a) 89 16 8 3.5 A 200!15 61 - 1 10 6.5-B.040 17.2 3 b 78 9 5.OA4a) 200115 84-99 0-1 6-7 7.0 >80 17.9 5.0 A 200/15 48 - 1 - 7 - 7.5 >80 15~
4 b) 61 2 8 11 5.0 A 20dt 53 - 1 7 - 7.0 >80 17.1 4 c 5 72 8 12 3.5 A 200/15 67 - 1 17 - 9.0 >80 17.4 5 a) 92 18 13 3.5 A 200115 57 - 0 19 8.5-9.060 14.8 5 b) 72 14 3.5 A 200!25 63 - 0 31 - 8.5 60 13 2 5 c) 77 32 t5 5.OA6a) 200115 59-72 0 5 8.0 >BO 15.1 16 5 0 A 200!15 77 - 1 25 - 9.0 >80 13.0 6 b) 103 26 17 3.5 A 200115 76 - 1 19 8Ø5 >80 12.8 7 a) 65 18 3.SA7b 200125 75-91 0-1 16-17 9.0 60 12.7 19 5.0 A 200115 10 - 1 8 8.0-0.5>80 11.6 8 a) 55 5.0 A 200115 50 - 1 31 - 9.0 >80 11.0 8 b 62 34 21 3.5 A 200115 76 - 0 14 8.0 60 18.0 9 a) 90 22 3.5 A 20W15 82 - 0 12 6.5-7.060 18.4 9 b 92 1 13 23 5.0 A 200/15 57 - 0 - 6 - 7.5-0.5>80 13.6 10 a) 64 1 7 24 5.0 A 200!15 78 - 1 7 - 6.5-7.0>80 16.2 10 b) 82 9 5.0 A 200115 36 . t 12 - 7.5-8.0>80 13.
10 c) 5p 15 t 26 3.5 A 200/15 47 - 0 16 - 8.0-8.5>80 13.9 11 a) 62 17 27 3.5 A 200115 67 - 1 14 - 6.0 >80 14.7 11 b) 80 15 28 3.5 A 200115 77 - 0 20 7.5 60 10.6 11 c 88 29 5.0 A 200/15 44 - 1 6 8.0 >80 12.5 12 a) 58 5 0 A 200/15 48 - 1 30 - 8.5-9.0>80 10.1 12 b) 68 31 31 3.5 A 200/15 58 - 0 - 17 8.0-8.580 16.3 13 a) 81 1 32 3.5 A 200125 72 - 1 11 4.0-7.040 15.0 13 c) 92 33 5.0 A 200115 77 - 0 5 7.0-7.5>80 14.5 14 a) 91 34 5.0 A 200r25 90 - 0 8 6.0 >80 13.1 14 b 105 1 D Carboxyl-containing pol~resters To prepare a hybrid powder coating composition the carboxyl-containing polyesters described below were employed, having the following characteri-O.Z. 5290 stic data:
Table 4: Characteristic data of the acidic polyester Example D 1 Characteristic data Acid number 30 mg of KOH/
Meltin ran a 78 - 81 C
Glass transition tem erature 64 C
E Hybrid powder coating examples The preparation of the raw materials, and also the preparation and ap-plication of the coatings, is as in C. The hybrid powder coatings comprise epoxy resin and polyesterpolycarboxylic acids in a ratio of 75 : 25, 40% by mass white pigment (Ti02) and 1 % by mass leveling agent.
O.Z. 5290 Table 5: Coatings Examples Example,CrossllnkerCuring Mechanical ac- data eordlnq to E f t by 'Gmin LT GG 60' EI 81 weight: 4 dir.
~
1 5.0 A 2 200115 60 16 7.07.5>60 b -2 7.5 A 3 20011 55 13 6.5-9.5>80 a) S -3 3.5 A 3 200115 59 12 6.57.040 b) -d J.5 A 3 200115 44 12 3.55.570 c 65 5 5.0 A 4 200V15 44 9 7.0-7.5>80 a) 84 6 5.0 A 4 200Y15 48 9 8.0 >60 b -7 5.0 A 6 200115 55 10 xØ8.5>60 a -6r!
8 5.0 A 8 20W15 81 18 7 5-8.0>80 s -9 3.5 A 11 200115 58 18 9.0 70 a) -10 J.5 A 11 20W 55 1 tl 9.5 70 b) 15 -11 3.5 A 11 200115 57 19 9.5 80 c .
t)D
12 3.5 A 17 200115 60 15 9Ø9.5>80 a) -13 3.5 A 13 200115 59 15 9.0 >80 b) -14 3.5 A 13 200!15 5 t 16 9 0.9.570 c -O.Z. 5290
~
1 5.0 A 2 200115 60 16 7.07.5>60 b -2 7.5 A 3 20011 55 13 6.5-9.5>80 a) S -3 3.5 A 3 200115 59 12 6.57.040 b) -d J.5 A 3 200115 44 12 3.55.570 c 65 5 5.0 A 4 200V15 44 9 7.0-7.5>80 a) 84 6 5.0 A 4 200Y15 48 9 8.0 >60 b -7 5.0 A 6 200115 55 10 xØ8.5>60 a -6r!
8 5.0 A 8 20W15 81 18 7 5-8.0>80 s -9 3.5 A 11 200115 58 18 9.0 70 a) -10 J.5 A 11 20W 55 1 tl 9.5 70 b) 15 -11 3.5 A 11 200115 57 19 9.5 80 c .
t)D
12 3.5 A 17 200115 60 15 9Ø9.5>80 a) -13 3.5 A 13 200115 59 15 9.0 >80 b) -14 3.5 A 13 200!15 5 t 16 9 0.9.570 c -O.Z. 5290
Claims (25)
1. A powder coating composition which comprises:
an epoxy resin or a carboxyl-functional polyester resin mixed with an epoxy resin, and as a hardener, a physical mixture consisting of:
a) a salt of:
a1) an aliphatic, cycloaliphatic, araliphatic or aromatic polycarboxylic acid other than isophthalic acid, terephthalic acid and phthalic acid, with a2) an amine of the formula:
~~~~ (wherein R1, R2 and R3 are identical or different and are each
an epoxy resin or a carboxyl-functional polyester resin mixed with an epoxy resin, and as a hardener, a physical mixture consisting of:
a) a salt of:
a1) an aliphatic, cycloaliphatic, araliphatic or aromatic polycarboxylic acid other than isophthalic acid, terephthalic acid and phthalic acid, with a2) an amine of the formula:
~~~~ (wherein R1, R2 and R3 are identical or different and are each
2,2,6,6-tetramethylpiperidin-4-yl or an aliphatic, cyclo-aliphatic, araliphatic or aromatic hydrocarbon radical having 1 - 20 carbon atoms, in which one or more CH2 groups in a C
chain may be replaced by O, CH-OH or NR4 where R4 is C1-6-alkyl or one or more terminal methyl groups may be replaced by a dialkylamino group having 1 to 6 carbon atoms in each alkyl.
group or R1 and R2 together with the N atom to which they are attached form a conjoint ring in which one CH2 group may be replaced by O, NR4, R1 and R2 in the formula C) may also be hydrogen or R1, R2 and R3 in the formula A) are each -CH2-CH2- attached via a conjoint N atom, and n is 3 - 11) or a3) a guanidine compound of the formula:
(wherein R5, R6, R7, R8 and R9 independently of one another are identical or different and are an aliphatic, cycloaliphatic, araliphatic or aromatic hydrocarbon radical having 1 - 9 carbon atoms or hydrogen or R6 and R7 together or R8 and R9 together with the N atom to which they are attached form a conjoint ring which may include an oxygen atom as heteroatom), and b) an aliphatic, cycloaliphatic, araliphatic or aromatic polycarboxylic acid, in a ratio a) : b) of from 99 : 1 to 1 : 99.
2. The powder coating composition as claimed in claim 1, wherein the polycarboxylic acid a1) is a tri- or tetracarboxylic acid.
chain may be replaced by O, CH-OH or NR4 where R4 is C1-6-alkyl or one or more terminal methyl groups may be replaced by a dialkylamino group having 1 to 6 carbon atoms in each alkyl.
group or R1 and R2 together with the N atom to which they are attached form a conjoint ring in which one CH2 group may be replaced by O, NR4, R1 and R2 in the formula C) may also be hydrogen or R1, R2 and R3 in the formula A) are each -CH2-CH2- attached via a conjoint N atom, and n is 3 - 11) or a3) a guanidine compound of the formula:
(wherein R5, R6, R7, R8 and R9 independently of one another are identical or different and are an aliphatic, cycloaliphatic, araliphatic or aromatic hydrocarbon radical having 1 - 9 carbon atoms or hydrogen or R6 and R7 together or R8 and R9 together with the N atom to which they are attached form a conjoint ring which may include an oxygen atom as heteroatom), and b) an aliphatic, cycloaliphatic, araliphatic or aromatic polycarboxylic acid, in a ratio a) : b) of from 99 : 1 to 1 : 99.
2. The powder coating composition as claimed in claim 1, wherein the polycarboxylic acid a1) is a tri- or tetracarboxylic acid.
3. The powder coating composition as claimed in claim 2, wherein the tri- or tetracarboxylic acid is aliphatic or cycloaliphatic.
4. The powder coating composition as claimed in claim 3, wherein the aliphatic or cycloaliphatic tri- or tetracarboxylic acid is 1,2,3,4-butanetetracarboxylic acid, ethylenediamine-tetraacetic acid, nitrilotriacetic acid, cyclopentanetetra-carboxylic acid, citric acid or aconitic acid.
5. The powder coating composition as claimed in claim 2, wherein the tri- or tetracarboxylic acid is aromatic.
6. The powder coating composition as claimed in claim 5, wherein the aromatic tri- or tetracarboxylic acid is cyanuric acid, trimellitic acid or trimesic acid.
7. The powder coating composition as claimed in claim 5, wherein the aromatic tri- or tetracarboxylic acid is pyro-mellitic acid.
8. The powder coating composition as claimed in claim 1, wherein the polycarboxylic acid a1) is an aliphatic or cyclo-aliphatic polycarboxylic acid.
9. The powder coating composition as claimed in claim 8, wherein the polycarboxylic acid a1) is an aliphatic or cyclo-aliphatic di-, tri- or tetracarboxylic acid.
10. The powder coating composition as claimed in claim 1, wherein the polycarboxylic acid a1) is cyanuric acid, 2,2,4-(2,4,4)-trimethyladipic acid, 1,2,3,4-butanetetracarboxylic acid, ethylenediaminetetraacetic acid, diethylenetriamine-pentaacetic acid, nitrilotriacetic acid, hexahydrophthalic acid, hexahydroisophthalic acid, hexahydroterephthalic acid, pyro-mellitic acid, trimellitic acid, trimesic acid, cyclopentane-tetracarboxylic acid, citric acid, aconitic acid or 2,6-naphthalenedicarboxylic acid.
11. The powder coating composition as claimed in any one of claims 1 to 10, wherein the salt a) is of the amine of the formula A), B) or C).
12. The powder coating composition as claimed in claim 11, wherein the amine has the formula A).
13. The powder coating composition as claimed in claim 12, wherein in the formula A), R1, R2 and R3 are each C1-20 alkyl, phenyl or cyclohexyl or the amine is N-methylmorpholine, N,N-dimethylpiperazine, 2,2,6,6-tetramethyl-4-dimethylamino-piperidine, N,N,N',N'-tetramethylhexamethylenediamine or 1,4-diazabicyclo[2.2.2]octane.
14. The powder coating composition as claimed in claim 11, wherein the amine has the formula C) in which R1 and R2 are each hydrogen, C1-6-alkyl, or phenyl.
15. The powder coating composition as claimed in any one of claims 1 to 10, wherein the salt a) is of the guanidine compound of the formula D).
16. The powder coating composition as claimed in any one of claims 1. to 10, wherein the salt a) is of N,N-dimethylcyclo-hexylamine, N,N-dimethylaniline, N-methylmorpholine, N,N'-dimethylpiperazine, 2,2,6,6-tetramethyl-4-dimethylamino-piperidine, N,N-dimethyloctadecylamine, 1,8-diazabicyclo[5.4.0]-undec-7-ene, N,N,N',N'-tetramethylhexamethylenediamine, 1,4-diazabicyclo[2.2.2]octane, 2-phenylimidazoline, 2-methyl-imidazoline, 2,4-dimethylimidazoline, 2-ethyl-4-methylimidazoline, tetramethylguanidine, tetramethylcyclohexylguanidine, N,N',N"-triphenylguanidine or N,N'-dicyclohexyl-4-morpholine-carboxamide.
17. The powder coating composition as claimed in claim 1, wherein the salt a) is of pyromellitic acid as the polycarboxylic acid a1) and 2-phenylimidazoline as the amine a2).
18. The powder coating composition as claimed in any one of claims 1 to 1.7, wherein the salt is formed with 0.5 - 3 mols of the amine a2) or the guanidine compound a3) per mol. of the polycarboxylic acid a1) or its anhydride.
19. The powder coating composition as claimed in any one of claims 1 to 1.8, wherein the polycarboxylic acid b) is cyanuric acid, 2,2,4(2,4,4)-trimethyladipic acid, 1,2,3,4-butanetetracarboxylic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, nitrilotriacetic acid, isophthalic acid, terephthalic acid, phthalic acid, hexahydrophthalic acid, hexahydroisophthalic acid, hexahydroterephthalic acid, pyromellitic acid, trimellitic acid, trimesic acid, cyclopentanetetracarboxylic acid, citric acid, aconitic acid or 2,6-naphthalenedicarboxylic acid.
20. The powder coating composition according to claim 1, wherein the hardener is a mixture of a salt of pyromellitic acid and 2-phenylimidazoline, and a polycarboxylic acid selected from the group consisting of cyanuric acid, ethylene-diaminetetraacetic acid, isophthalic acid, terephthalic acid, 1,2,3,4-butanetetracarboxylic acid, trimellitic acid and trimesic acid.
21. The powder coating composition as claimed in any one of claims 1. to 20, which comprises the hardener in an amount of 2 - 14% by weight based on the epoxy resin or the carboxyl-functional. polyester resin mixed with the epoxy resin.
22. The powder coating composition as claimed in any one of claims 1 to 21, wherein the epoxy resin has a melting point of 60 - 150°C and contains on average more than one 1,2-epoxide group per molecule.
23. The powder coating composition as claimed in any one of claims 1 to 22, wherein the epoxy resin is based on a reaction product of bisphenol A and epichlorohydrin and has an epoxide equivalent weight of 400 - 3,000.
24. The powder coating composition as claimed in any one of claims 1 to 23, which comprises the carboxyl-functional polyester resin mixed with the epoxy resin, wherein the carboxyl-functional polyester resin has a melting point of 60 - 160°C, an acid number of 10 - 150 mg of KOH/g and an OH
number of below 10 mg of KOH/g.
number of below 10 mg of KOH/g.
25. A method of forming a semi-glossy to matt coating layer on a substrate, which comprises:
applying the powder coating composition as defined in any one of claims 1 to 24 on the substrate, and curing the powder coating composition at a temperature of 150 - 220°C.
applying the powder coating composition as defined in any one of claims 1 to 24 on the substrate, and curing the powder coating composition at a temperature of 150 - 220°C.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19806225.7 | 1998-02-16 | ||
| DE19806225A DE19806225A1 (en) | 1998-02-16 | 1998-02-16 | Epoxy resin and hybrid powder coating compositions |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2261485A1 true CA2261485A1 (en) | 1999-08-16 |
Family
ID=7857821
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002261485A Abandoned CA2261485A1 (en) | 1998-02-16 | 1999-02-12 | Epoxy resin and hybrid powder coating compositions |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0936236A2 (en) |
| KR (1) | KR19990072673A (en) |
| CA (1) | CA2261485A1 (en) |
| DE (1) | DE19806225A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9751973B2 (en) | 2010-06-24 | 2017-09-05 | Hexion Inc. | Epoxy systems for composites |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103788735B (en) * | 2012-10-29 | 2017-09-05 | 中冶建筑研究总院有限公司 | A kind of solvent-free flexible corrosion protection epoxy coating and preparation method thereof and application method |
| DE102014210708A1 (en) * | 2014-06-05 | 2015-12-17 | Siemens Aktiengesellschaft | Process for corrosion protection treatment |
-
1998
- 1998-02-16 DE DE19806225A patent/DE19806225A1/en not_active Withdrawn
- 1998-12-21 EP EP98124385A patent/EP0936236A2/en not_active Withdrawn
-
1999
- 1999-02-12 CA CA002261485A patent/CA2261485A1/en not_active Abandoned
- 1999-02-13 KR KR1019990005192A patent/KR19990072673A/en not_active Application Discontinuation
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9751973B2 (en) | 2010-06-24 | 2017-09-05 | Hexion Inc. | Epoxy systems for composites |
| US9920161B2 (en) | 2010-06-24 | 2018-03-20 | Hexion Inc. | Epoxy systems for composites |
Also Published As
| Publication number | Publication date |
|---|---|
| DE19806225A1 (en) | 1999-08-19 |
| KR19990072673A (en) | 1999-09-27 |
| EP0936236A2 (en) | 1999-08-18 |
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