Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
1999-10-19
2002-07-09
Lovering, Richard D. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
C523S410000, C523S428000, C525S526000, C525S939000, C528S088000
Reexamination Certificate
active
06417316
ABSTRACT:
The present invention relates to curable epoxy resin compositions, which are obtainable by heating a composition containing at least one epoxy compound, which contains on average at least one, preferably more than one, 1,2-epoxy group and optionally also one or several hydroxyl groups in the molecule, in the presence of at least one specific Lewis acid as catalyst. Such an epoxy resin composition mixture contains both the monomeric starting compound and high molecular weight epoxy compounds formed from the starting compound during heating.
Mixtures which are curable by thermosetting, for example two-component systems, and which contain an epoxy resin, i.e. an epoxy compound, which preferably contains on average more than one 1,2-epoxy group in the molecule, as well as a suitable hardener, are known. Thus, for example, epoxy resins containing on average two or more epoxy groups in the molecule are reacted or crosslinked with amino group-containing compounds (hardeners) in the absence or presence of suitable catalysts. After crosslinking or curing, such mixtures (EP-resins) yield cured products having different properties depending on the amount of the individual components used. Casting compositions, primary adhesives and thin coatings prepared from such per se known epoxy resins generally have the disadvantage that they are attacked within a short time by weathering and light. Coatings produced from such products usually turn dull, yellow and chalky very quickly.
Surprisingly, it has now been found that the performance properties of fully cured EP-resins are markedly improved if the epoxy compound is heated in the presence of a specific Lewis acid prior to being mixed with the hardener, the epoxy compound polymerising in part in an addition reaction, an epoxy resin composition being thus obtained which contains both the monomeric starting compound and the high molecular weight epoxy compounds formed during heating. It has also been found that the epoxy resin composition thus obtained can also be fully cured without any hardener being added, and that identically improved product properties can be obtained. In addition, it has been found that according to this invention the epoxy resins used can be epoxy compounds which contain in the same molecule at least one 1,2-epoxy group as well as one or several hydroxyl groups.
The present invention is defined in the patent claims. This invention relates in particular to curable epoxy resin compositions which are obtainable by heating a composition containing at least one epoxy compound, which contains on average at least one 1,2-epoxy group and optionally also one or several hydroxyl groups in the molecule, in the presence of at least one specific Lewis acid until the epoxy resin content, measured in equivalent epoxy/kg (Eq/kg) of the starting material, has been reduced by 1 to 60 percent, preferably by 5 to 50 percent. The Lewis acid is then preferably deactivated with a deactivator (quencher) in order to increase the storability of the epoxy resin composition obtained. The epoxy compound preferably contains at least two 1,2-epoxy groups.
This invention also relates to a process for the preparation of the novel curable epoxy resin compositions, which comprises heating a composition containing at least one epoxy compound which contains on average at least one or several 1,2-epoxy groups and optionally also one or several hydroxyl groups in the molecule, in the presence of at least one specific Lewis acid until the epoxy resin content has been reduced by 1 to 60 percent, preferably by 5 to 50 percent, and deactivating the Lewis acid with a deactivator, if required.
This invention furthermore relates to the use of the novel curable epoxy resin compositions for the preparation of fully cured moulded compositions or coatings (i) singly (homopolymerisation) or (ii) in admixture with at least one hardener in a heat-curable thermoset multicomponent system. This invention also relates to moulded compositions and coatings prepared in this manner.
In another of its aspects, this invention relates to heat-curable thermoset multicomponent systems comprising an epoxy resin composition curable in accordance with this invention.
This invention also relates to a divided package, the one part of which contains the epoxy resin composition curable according to this invention and the other part contains a suitable hardener.
This invention furthermore relates to the novel high molecular weight epoxy compounds which are formed while the epoxy compounds used as starting product are being heated.
Epoxy resins suitable for use in the process for obtaining the curable mixtures are the epoxy resins conventionally used in the epoxy resin technology. Examples of epoxy resins are:
I) Polyglycidyl- and poly(&bgr;-methylglycidyl)esters, obtainable by reacting a compound containing at least two carboxyl groups in the molecule with epichlorohydrin or &bgr;3-methylepichlorohydrin. Possible compounds containing at least two carboxyl groups in the molecule may be aliphatic polycarboxylic acids. Examples of such polycarboxylic acids are oxalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, sebacic acid, subaric acid, azelaic acid or dimerised or trimerised linoleic acid. It is also possible to use cycloaliphatic polycarboxylic acids, for example tetrahydrophthalic acid, 4-methyltetrahydrophthalic acid, hexahydrophthalic acid or 4-methylhexahydrophthalic acid. Aromatic polycarboxylic acids may also be used, for example phthalic acid, isophthalic acid, terephthalic acid, trimellitic or pyromellitic acid. It is preferred to use reaction products of acids containing two carboxyl groups in the molecule with epichlorohydrin and/or &bgr;-methylepichlorohydrin.
II) Polyglycidyl- or poly(&bgr;-methylglycidyl)ethers, obtainable by reacting a compound containing at least two free alcoholic hydroxyl groups and/or phenolic hydroxyl groups under alkaline conditions or in the presence of an acid catalyst with subsequent treatment with alkali. The glycidyl ethers of this type are derived, for example, from acyclic alcohols, such as from ethylene glycol, diethylene glycol and higher poly(oxyethylene)glycols, propane-1,2-diol or poly(oxypropylene)glycols, propane-1,3-diol, butane-1,4-diol, poly(oxytetramethylene)-glycols, pentane-1,5-diol, hexane-1,6-diol, hexane-2,4,6-triol, glycerol, 1,1,1-trimethylolpro-pane, pentaerythritol, sorbitol, and from polyepichlorohydrins. They are also derived, for example, from cycloaliphatic alcohols, such as 1,4-cyclohexanedimethanol, bis(4-hydroxy-cyclohexyl)methane or 2,2-bis(4-hydroxycyclohexyl)propane. The glycidyl ethers can also be derived from mononuclear phenols, for example from resorcinol or hydroquioone, or they are based on polynuclear phenols, such as bis(4-hydroxyphenyl)methane, 4,4′-dihydroxy-biphenyl, bis(4-hydroxyphenyl)sulfone, 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane and on novolaks, obtainable by condensation of aldehydes, such as formaldehyde, acetaldehyde, chloral or furfuraldehyde, with phenols, such as phenol, or with phenols which are substituted in the nucleus by chlorine atoms or C
1
-C
9
alkyl groups, for example 4-chlorophenol, 2-methylphenol, or 4-tert-butylphenol, or by condensation with bisphenols, such as those of the type mentioned above. It is preferred to use reaction products of compounds containing two free alcoholic hydroxyl groups and/or phenolic hydroxyl groups with epichlorohydrin and/or &bgr;-methylepichlorohydrin.
III) Poly(N-glycidyl)compounds, obtainable by dehydrochlorination of the reaction products of epichlorohydrin with amides or imides, which contain at least two amide or imide hydrogen atoms. These amides or imides are, for example, triglycidylisocyanurate, N,N′-diglycidyl derivatives of cycloalkylene ureas, such as ethylene urea or 1,3-propylenurea, and diglycidyl derivatives of hydantoins, such as of 5,5-dimethylhydantoin. It is preferred to use reaction products of amides or imides containing two re
Fischer Walter
Wiesendanger Rolf
Lovering Richard D.
Lyon & Lyon LLP
Vantico Inc.
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