Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1999-06-14
2001-07-10
Yoon, Tae H. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S591000, C525S107000, C525S208000, C427S386000, C427S407100
Reexamination Certificate
active
06258874
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to binder compositions having a very high working solids content which are suitable for the production of coating compositions which are stoved at elevated temperature and in particular are suitable for the production of multilayer lacquer coatings, for example in the automotive sector.
BACKGROUND OF THE INVENTION
DE-A-30 22 996 discloses a stoving lacquer, in which polymers containing carboxyl groups, such as for example acrylates based on acrylic acid or methacrylic acid, and acrylates containing glycidyl groups are mixed together to yield a curable composition.
WO 84/00771 describes a multicomponent system in which four types of binders are mixed together and then applied. The components comprise acrylate containing hydroxyl groups, acid anhydride, wherein at least 50% are alkylhexahydrophthalic anhydrides, epoxy resin and melamine resin. The systems have an elevated solids content.
DE-A-23 33 384 describes a binder based on acrylated polyesters, which are obtained by polymerising an acrylate containing hydroxyl groups in a polyester or alkyd resin containing hydroxyl groups. Crosslinking may be performed with melamine resins and simultaneously epoxy resins.
Some of the known coating compositions give rise to films having elevated hardness and good resistance to weathering. However, they do not satisfy the constantly increasing requirements for elevated resistance to acids and solvents. Moreover, they do not meet the requirement for a very high working solids content.
SUMMARY OF THE INVENTION
The object of the invention is to provide coating compositions having an elevated working solids content which are suitable for coatings having elevated hardness and improved resistance to weathering, acids and solvents.
It has been found that this object may be achieved by a binder composition, which is provided by the invention and contains:
A) 30 to 80 wt. % of one or more carboxy-functional polymers, the carboxyl functionality of which in each case corresponds to an acid value of 15 to 300 mg of KOH/g,
B) 3 to 30 wt. % of one or more compounds having an epoxide function in the molecule,
C) 0 to 60 wt. % of one or more polyols having at least two hydroxyl functions in the molecule, which differ from a component A) optionally containing hydroxyl functions,
D) 0 to 40 wt. % of components which crosslink with hydroxyl groups to form ethers and/or a triazine-based crosslinking agent,
E) 0 to 40 wt. % of one or more polyisocyanates, which may optionally be capped,
F) 0 to 60 wt. % of an anhydride component consisting of at least one organic polyanhydride having at least two cyclic carboxylic anhydride groups per molecule,
G) 0 to 10 wt. % of one or more catalysts for catalysing the reaction of carboxyl and epoxide groups,
wherein the sum of weight percentages of components A) to G) adds up to 100 wt. % and wherein at least 10 wt. % of the binder composition consists of one or more of components D), E) and/or F).
This invention also relates to coating compositions which may be produced from the binder compositions according to the invention. These coating compositions may comprise aqueous and/or solvent-containing coating compositions, which may optionally contain pigments, extenders and/or conventional lacquer auxiliary substances and additives; they may also be formulated as powder coatings containing neither solvent nor water.
Various compounds may be used as the carboxy-functional polymer A). These comprise the conventional resins having carboxyl groups which may be used in lacquers. For example, (meth)acrylic copolymers, polyesters, polyester/(meth)acrylic copolymers or mixtures thereof, which are carboxy-functional and optionally contain hydroxyl groups and optionally urethane groups, may be used. Poly(meth)acrylic polyols, polyester polyols, polyester/(meth)acrylic polyols, polyurethane polyols or mixtures thereof, which are carboxy-functional and optionally contain urethane groups, are, for example, suitable.
When producing (meth)acrylic copolymers or polyester/(meth)acrylic copolymers usable as component A) which contain carboxyl groups and optionally in each case contain urethane groups, the carboxyl groups may be introduced directly by using structural units containing carboxyl groups, for example during the synthesis of polymers, such as (meth)acrylic copolymers. Examples of monomers containing carboxyl groups suitable for this purpose are unsaturated carboxylic acids, such as for example acrylic, methacrylic, itaconic, crotonic, isocrotonic, aconitic, maleic and fumaric acid, semi-esters of maleic acid and fumaric acid, as well as carboxyalkyl esters of (meth)acrylic acid, for example &bgr;-carboxyethyl acrylate and addition products of hydroxyalkyl esters of acrylic acid and/or methacrylic acid with carboxylic anhydrides, such as for example phthalic acid mono-2-(meth)acryloyloxyethyl ester.
The term (meth)acrylic is used in the present description and the patent claims. The term means acrylic and/or methacrylic.
When producing (meth)acrylic copolymers or polyester/(meth)acrylic copolymers containing carboxyl groups and optionally containing urethane groups, it is, however, also possible initially to synthesise a polymer containing hydroxyl groups and optionally also already carboxyl groups having an OH value of 15 to 300 mg of KOH/g and to introduce the carboxyl groups wholly or in part in a second stage by reaction with carboxylic anhydrides. Using this method, it is possible to operate with quantity ratios such that sufficient OH groups optionally remain in order to be able to perform urethanisation or in order to allow crosslinking with components D) to F).
Carboxylic anhydrides suitable for addition onto the polymers which contain hydroxyl groups and may optionally also already contain carboxyl groups are the anhydrides of aliphatic, cycloaliphatic and aromatic saturated and/or unsaturated di- and polycarboxylic acids, such as for example the anhydrides of phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, succinic acid, maleic acid, itaconic acid, glutaric acid, trimellitic acid and pyromellitic acid, as well as the halogenated or alkylated derivatives thereof.
Anhydrides of phthalic acid, tetrahydro- and hexahydrophthalic acid as well as 5-methylhexahydrophthalic anhydride are preferably used.
Monomers suitable for introducing hydroxyl groups into the (meth)acrylic copolymers or polyester/(meth)acrylic copolymers optionally containing urethane groups are, for example, hydroxyalkyl esters of &agr;,&bgr;-unsaturated carboxylic acids, such as (meth)acrylic acid, for example having primary hydroxyl groups, such as for example hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyamyl acrylate, hydroxyhexyl acrylate, hydroxyoctyl acrylate and the corresponding methacrylates. Examples of usable hydroxyalkyl esters having a secondary hydroxyl group which may be mentioned are 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 3-hydroxybutyl acrylate and the corresponding methacrylates. These hydroxyalkyl esters are, for example, also suitable for the production of the addition products with carboxylic anhydrides described for the synthesis of component A).
The hydroxy-functionalised component may advantageously at least in part comprise a reaction product of 1 mol of hydroxyethyl acrylate and/or hydroxyethyl methacrylate and on average 2 mol of &agr;-caprolactone.
A reaction product prepared from acrylic acid and/or methacrylic acid with the glycidyl ester of a carboxylic acid having a tertiary &agr;-carbon atom may also be used at least in part as the hydroxy-functionalised component. Glycidyl esters of highly branched monocarboxylic acids are obtainable, for example, under the trade name “Cardura”. The acrylic acid or methacrylic acid may react with the glycidyl ester of a carboxylic acid having a tertiary &agr;carbon atom before, during or after the polymerisation reaction.
Apart from the above-stated monomers, further ethylenically unsaturated monomers may also be used for the production of
Duecoffre Volker
Schubert Walter
Herberts GmbH & Co. KG
Pillsbury & Winthrop LLP
Yoon Tae H.
LandOfFree
Binder agent composition, coating agents containing them,... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Binder agent composition, coating agents containing them,..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Binder agent composition, coating agents containing them,... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2508008