Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
1999-07-13
2001-04-03
Hampton-Hightower, P. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
C528S045000, C528S172000, C528S173000, C528S183000, C528S188000, C528S220000, C528S228000, C528S229000, C528S288000, C528S310000, C528S317000, C528S322000, C525S437000, C525S453000, C524S538000, C524S539000, C524S541000, C524S600000, C524S602000, C427S118000, C427S120000
Reexamination Certificate
active
06211326
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a process for preparing carboxyl- and hydroxyl-containing polyesterimides, to their use as binders and to wire enamels comprising such binders.
BACKGROUND OF THE INVENTION
The wire enamels commonly employed today are in general solutions of the typical binders, for example polyesterimides, in solvents, alone or in combination with customary commercial hydrocarbon cuts.
Polyesterimide enamels are known, for example, from DE-A 1445263 and 1495100 and from WO 91/07469 (PCT-EP 90/01911). Because of their good mechanical, thermal and chemical properties they have found broad application in the wire-coating industry.
The preparation of these polyesterimides takes place in a known manner from polyols, polycarboxylic acids or derivatives thereof and from imide-forming components.
SUMMARY OF THE INVENTION
The wire enamels known from the prior art, based on polyesterimides, combine the proven good enamel properties with, however, only limited coating rates, which are critically dependent on the evaporation rate of the low molecular mass reaction produces in the course of curing of the wire enamels.
The object of the present invention, therefore, was to provide wire enamels which allow improved coating rates and at the same time lead to enamel films having particularly good properties, such as, in particular, good adhesion to the wires, high breakdown voltage, high softening temperature, sufficiently high thermal shock, and high outer-fiber extension. Moreover, the wire coating compositions should combine a solids content which is as high as possible with a viscosity favorable for processing.
It has surprisingly been found that wire enamels comprising hydroxyl- and carboxyl-containing polyesterimides as binders meet these objects outstandingly. In this case, the hydroxyl- and carboxyl-containing polyesterimides have acid numbers of at least 80 mg of KOH/g and are composed of the following monomeric components:
(A) imide-forming compounds having at least two primary amino groups and/or at least two isocyanate groups or imide-forming compounds having at least one primary amino group and/or at least one isocyanate group and at least one further functional group selected from hydroxyl, carboxyl and/or carboxylic anhydride,
(B) polycarboxylic acids and/or their anhydrides and/or their esters and
(C) polyols.
Also embraced by the invention is a process for preparing hydroxyl- and carboxyl-containing polyesterimide resins, comprising the monomeric components (A), (B) and (C), embracing the following individual steps (stages):
(I) the reaction of component (A) with part of component (B) to form a polyimide,
(II) the reaction of the polyimide obtained in accordance with stage (I) with component (C) to form a polyesterimide, and finally
(III) the reaction of the polyesterimide obtained in accordance with stage (II) with the remaining part of component (B) to form the hydroxyl- and carboxyl-containing polyesterimide,
and the use of the hydroxyl- and carboxyl-containing polyesterimides prepared in this way as binders in coating compositions.
DETAILED DESCRIPTION OF THE INVENTION
The Monomeric Components (A), (B) and (C) of the Hydroxyl- and Carboxyl-containing Polyesterimide According to the Invention
Monomeric components (A) having primary amino groups which may be mentioned in particular by way of example are diprimary diamines, for example ethylenediamine, tetramethylenediamine, hexamethylenediamine, nonamethylenediamine and other aliphatic diprimary diamines.
Also suitable as monomeric components (A) are aromatic diprimary diamines, such as benzidine, diaminodiphenylmethane, diaminodiphenyl sulfone, diaminodiphenyl sulfoxide, diaminodiphenyl ether, diaminodiphenyl tioether[sic], phenylenediamines, tolylenediamines, and diamines with three benzene rings in the molecule, for example 1,4-bis(4-aminophenoxy)benzene. Also suitable, finally, are cycloaliphatlc diamines, such as 4,4′,-dicyclohexylmethanediamine[sic], for example.
As amino-containing component (A) with a further functional group it is possible, for example, to use amino alcohols, for example monoethanolamine and monopropanolamines, and also aminocarboxylic acids, such as glycine, aminopropanoic acid, aminocaproic acids or aminobenzoic acids, and also their esters or anhydrides.
Examples of components (A) with isocyanate groups are, in particular, diprimary isocyanates, for example propylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, ethylethylene diisocyanate, 3,3,4-trimethylhexamethylene diisocyanate, 1,3-cyclopenthyl[sic]diisocyanate, 1,4,-cyclohexyl[sic]diisocyanate, 1,2-cyclohexyl diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,5-tolylene diisocyanate, 2,6,-tolylene[sic]diisocyanate, 4,4′-biphenylene diisocyanate, 1,5-naphthylene diisocyanate, 1,4-naphthylene diisocyanate, 1-isocyanatomethyl-5-isocyanato-1,3,3-trimethylcyclohexane, bis(4-isocyanatocyclohexyl)methane, bis(4-isocyanatophenyl)methane, 4,4′-diisocyanatodiphenyl ether and 2,3-bis(8-isocyanatooctyl)-4-octyl-5-hexylcyclohexene. It is possible, furthermore, to employ industrially available distillation cuts, for example Desmodur VL® or Voranate M590®. It is preferred to employ Desmodur VL®, Voranate M590®, an isomer mixture comprising the tolylene diisocyanates, and bis(4-isocyanatophenyl)methane.
Examples of polycarboxylic acids suitable as component (B) are phthalic acid, isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, and esterifiable derivatives thereof, for example anhydrides and the lower alkyl esters of said acids, for example methyl, ethyl, propyl, butyl, amyl, hexyl and octyl esters. It is also possible here to employ the monoesters, the diacyl esters and the mixtures of these compounds. Likewise suitable are the acid halides. Preferred components (B) are compounds having a cyclic carboxylic anhydride group and further functional groups, such as, with particular preference, pyromellitic dianhydride and trimellitic anhydride. However, other aromatic carboxylic anhydrides are also suitable as component (B), examples being the naphthalenetetracarboxylic dianhydrides or dianhydrides of tetracarboxylic acids having two benzene rings in the molecule where the carboxyl groups are in 3,3′4- and 4′-position[sic].
Also coming into consideration as component (B) are aliphatic dicarboxylic acids, for example oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, acelaic acid, sebacic acid, maleic acid, fumaric acid or sorbic acid, and their esterifiable or transesterifiable derivatives.
Alcohols suitable as component (C) are, in particular, diols and triols. Examples are ethylene glycol, 1,2- and 1,3-propylene glycol, 1,2-, 1,3- and 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, diethylene glycol, triethylene glycol, glycerol, trimethylolethane, trimethylolpropane and tris-2-hydroxyethyl isocyanurate. The latter trial is employed preferentially for the polyesterimide resins. Its use leads to particularly high softening temperatures of the wire coating composition.
Particular preference is given, as component (C), to the use of a mixture of dials and trials. Mixtures of ethylene glycol and tris-2-hydroxyethyl isocyanurate are employed especially in this case.
The Process According to the Invention for Preparing the Hydroxyl- and Carboxyl-containing Polyesterides, and the Hydroxyl- and Carboxyl-containing Polyesterimides Thus Prepared
The process according to the invention for preparing the hydroxyl- and carboxyl-containing polyesterimide is conducted in three stages:
(I) component (A) is reacted with a part, preferably from 50 to 90% by weight, based on (B), of component (B) to form a polyimide,
(II) the polyimide obtained in accordance with stage (I) is reacted with component (C) to form a polyesterimide, and finally
(III) the polyesterimide obtained in accordance with stage (II)
Glasper Brian W.
Lienert Klaus-Wilhelm
Rix Geoffrey C.
Hampton-Hightower P.
Pillsbury & Winthrop LLP
Schenectady International Inc.
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