Classifications

• • 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
• • 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
  • C08G59/02—Polycondensates containing more than one epoxy group per molecule
  • C08G59/12—Polycondensates containing more than one epoxy group per molecule of polycarboxylic acids with epihalohydrins or precursors thereof
• • 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
  • C08G63/60—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from the reaction of a mixture of hydroxy carboxylic acids, polycarboxylic acids and polyhydroxy compounds
• • 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
  • 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

Definitions

• the present invention relates to carboxyl functional polyester resins, to a process for the preparation of the resins, to polyglycidylester resins obtainable by glycidating said carboxyl functional polyester resins, to coating compositions, and in particular powder coating compositions or liquid coating compositions comprising said carboxyl functional polyester resins or said polyglycidylester resins, and to cured products obtained by using the indicated coating compositions.
• Powder coating compositions based on the solid reaction products of 2, 2-bis- ( 4-hydroxyphenyl) propane and epichlorohydrin are known already for a long time.
• the cured products prepared on the basis of these compositions are resistant against hydrolysis, however, they show a low ultraviolet resistance and are therefore not suitable for applications requiring a high degree of outdoor durability such as building parts or automotive topcoats.
• Triglycidylesters which can be used in good quality outdoor durable coatings and in moulding compositions are disclosed in European Patent Application No. 447360A (EP-A-447 , 360 ) .
• the triglycidylester produced will contain a relatively high level of hydrolizable chlorine and/or will contain low molecular weight hydrolysis products which might cause toxicity problems, as may be derived from "Water based coatings with excellent saponification stability Xlllth Int. Conf. 1987, Athens, Greece, p. 175.
• the high level of hydrolizable chlorine is reflected in example 2 of EP-A-447,360 which relates to the glycidation of the 2:1 adduct of hexahydrophthalic anhydride and dimethylolpropionic acid.
• the product obtained has a chlorine content of 1.5%.
• Such a high level of residual chlorine is generally undesirable in coating compositions.
• the triglycidylesters reported in EP-A-447,360 are liquid, they can not be applied in powder coating compositions .
• polyglycidylester resins obtainable by reacting said linear tertiary aliphatic carboxyl functional polyesters with an excess epihalohydrin in the presence of a suitable base and optional catalyst.
• the polyesters were reacted with epichlorohydrin .
• Both the specified linear polyesters and the corresponding polyglycidylesters derived therefrom were used with a cross-linking agent for powder coating compositions.
• polyester resins were obtainable by reaction of: a) at least one aromatic and/or cycloaliphatic carboxylic acid compound A comprising two aromatic- and/or secondary aliphatic carboxyl groups or the anhydride thereof, b) at least one hydroxyl compound B comprising two aliphatic hydroxyl groups, which groups each independently may be primary or secondary hydroxyl groups, c) at least one hydroxyl substituted carboxylic acid compound C comprising at least one tertiary aliphatic carboxyl group and two aliphatic hydroxyl groups, which groups each independently may be primary or secondary hydroxyl groups, and d) optionally one carboxylic acid compound D comprising one carboxyl group, the molar ratio of compounds A:B:C:D being
• polyester resins could be used together with a suitable curing agent for the production of powder coatings, or could be converted into the corresponding glycidylesters, which in combination with a suitable curing agent could be used for the production of powder coatings .
• linear tertiary aliphatic carboxyl functional polyester resins and the polyglycidylesters thereof enabled a certain progress as to the requirements of excellent outdoor durability (UV stability) and resistance against hydrolysis in the cured state, with reference to their use in modern economically applied powder coatings, there is still a need for further improvement of this combination of properties .
• the invention provides carboxyl functional polyester resins obtainable by reaction of: a) at least a compound of the formula 0 0
• Dl trihydroxyalkane
• D2 tetrahydroxy- alkane
• the optional component A2 are meant amounts of from 0 to 10 mole%, relative to the total molar amount of Al and A2.
• the aliphatic carboxyl functional polyester resins thus produced may only contain tertiary carboxyl groups pendant of the main chain, whereas only at each end of the main chain secondary carboxyl groups originating from 1,4-cyclo- hexane dicarboxylic acid, are present.
• Dependent on the actual presence of components (Dl) or ( D2 ) the main chain will be linear (components D are absent) or branched (component Dl and/or D2 is present) .
• glycidation of these non-terminal tertiary aliphatic carboxyl groups and the terminal secondary carboxyl groups with epihalohydrin can be performed under standard alkaline conditions, whereby a polyglycidylester resin can be obtained which contains a low hydrolizable halogen content, usually lower than 1% by weight and preferably lower than 0.7% by weight, based on the total weight of the composition.
• the process for preparation of the aliphatic carboxyl functional polyester may in general be carried out according to conventional esterification methods, preferably by azeotropic condensation, taking care that the terminal secondary carboxyl groups are only originating from 1, 4-cyclohexane dicarboxylic acid.
• the condensation is carried out by charging the compounds A, B, optionally C and optionally Dl or D2 , simultaneously to the reactor whereafter the temperature is increased from room temperature to a temperature in the range of from 180 to 240 °C, preferably from 180 to 210 °C in the presence of any compound B, during a period of 3 to 8 hours, thus allowing the reaction to initiate and to proceed under continuous azeotropic removal of water.
• esterification catalyst such as for example dibutyltinoxide, paratoluenesulphonic acid, tinoctoate, zincoctoate and lithium ricinoleate may be used in the esterification process, but is in general not required.
• a part of the total batch of e.g. 1 , 4-cyclohexane dicarboxylic acid to be included may be added during the reaction and more preferably in its last stage.
• Suitable compounds B for use in the process of the present invention include branched aliphatic-, cyclo- aliphatic-, or araliphatic compounds, containing two aliphatic hydroxyl groups, each individually being either a primary or a secondary hydroxyl group, such as for example propylene glycol, neopentyl glycol, hydrogenated diphenylolpropane (HDPP) , hydrogenated 4,4' -dihydroxydiphenyl, 1, 4-cyclohexanedimethylol, 1, -dihydroxycyclohexane, hydroxypivalylhydroxypivalate and 2-butyl-2-ethyl-l , 3-propanediol or mixtures thereof; of which HDPP is particularly preferred.
• HDPP hydrogenated diphenylolpropane
• a typical example of a suitable compound C for use in the process of the present invention is dimethylol propionic acid.
• a typical and preferred example of compound Dl to be used for the preparation of the branched carboxyl functional polyesters of the present invention is trimethylol propane and a preferred example of compound D2 is pentaerythritol .
• the aliphatic carboxyl functional polyester resin obtainable according to the process of the present invention can be easily converted to a polyglycidylester resin according to methods known in the art i.e. by reaction with an excess epihalohydrin in the presence of a suitable base and optionally a catalyst. Most conveniently epichlorohydrin is used.
• the curable powder coating compositions of the invention may be prepared by addition of a cross- linking resin to either the hereinbefore specified linear or branched or star shaped aliphatic carboxyl functional polyester resins of the present invention or to the polyglycidylester resin obtainable by glycidating said linear or branched aliphatic carboxyl functional polyester resin.
• the amount of cross-linking compound used in the powder coating compositions of the invention will normally be such so as to provide about equal amounts of reactive groups of the cross-linking compound and of the aliphatic carboxyl groups present in the linear or branched aliphatic carboxyl functional polyester resin or of the epoxy groups present in the polyglycidylester resin .
• Suitable cross-linking resins for use in combination with the aliphatic carboxyl functional polyester resins of the present invention are for example outdoor durable epoxy resins, such as for example the polyglycidylester resins according to the present invention, the diglycidylesters of alpha, alpha ' -dibranched dicarboxylic acids as disclosed in
• Suitable cross-linking resins for use in combination with the polyglycidylester resins of the present invention are for example the (corresponding) acid functional polyester resin of the present invention; solid polyacids such as sebacic acid,
• 1, 12-dodecanedioic acid 1, 12-dodecanedioic acid
• anhydrides such as polyazeleic polyanhydride
• acid functional polyesters such as the reaction product of one mole of trimethylolpropane
• the powder coating compositions of the present invention may further comprise a catalyst and optionally other additives, as known in the art to be suitable for use in powder coating compositions.
• Suitable catalysts are for example quaternary ammonium and phosphonium salts; metal salts/compounds such as for example stannous (II ) octoate; basic compounds such as for example the imidazoles; and tertiary amines such as for example diazabi- cycloundecene .
• the amount of catalyst used will usually be somewhere in the range of from 0.1 to 2% by weight based on the weight of the total powder coating composition .
• Suitable cure times and cure temperatures of the powder coating compositions of the invention are those conventionally applied in connection with powder coating systems.
• Example 1 The invention is illustrated by the following examples, however without restricting its scope to these specific embodiments.
• Example 1 The invention is illustrated by the following examples, however without restricting its scope to these specific embodiments.
• the mixture was then heated to 150 °C in 30 minutes.
• the temperature of the reaction mixture was increased in two hours to 210 °C and kept at 210 °C until at least 94% of the original hydroxyl groups have reacted.
• the acid functional polyester thus formed was discharged and allowed to cool down to room temperature .
• Numbers given represent the amount of moles of a particular compound charged to the reactor in the process of example 1 for the preparation of the linear tertiary carboxyl functional polyester resins 1 to 5.
• 1,4-CHCA 1 , 4-cyclohexanedicarboxylic acid
• HHPA hexahydrophthalic anhydride
• HDPP hydrogenated diphenylolpropane
• PENTA pentaerythritol
• MIBK methyl isobutyl ketone
• Modaflow III is an acrylic based flow aid available from Monsanto Co.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Polymers & Plastics (AREA)
• Health & Medical Sciences (AREA)
• Medicinal Chemistry (AREA)
• Wood Science & Technology (AREA)
• Materials Engineering (AREA)
• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Paints Or Removers (AREA)
• Epoxy Resins (AREA)
• Polyesters Or Polycarbonates (AREA)

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• 1998
  • 1998-03-24 EP EP98920497A patent/EP0971968A2/de not_active Withdrawn
  • 1998-03-24 WO PCT/EP1998/001903 patent/WO1998042768A2/en not_active Application Discontinuation
  • 1998-03-24 BR BR9808045-8A patent/BR9808045A/pt active Search and Examination

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