Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1998-01-05
2004-03-23
Wilson, Donald R. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C523S443000
Reexamination Certificate
active
06710105
ABSTRACT:
The present invention relates to a curable epoxy resin composition comprising wollastonite and a quartz/kaolinite mixture, which is suitable for the production of mouldings having high-gloss surfaces.
It is known to add fillers to curable epoxy resin compositions in order to obtain moulded materials therefrom which have improved mechanical properties. For production of mouldings with high-gloss properties from synthetic resin compositions, it is desirable for the mouldings also to have good mechanical and good thermal properties, in addition to a high-gloss surface.
To increase the surface gloss of mouldings, epoxy resins have hitherto merely been applied in the form of powder coatings to existing surfaces, onto which a metal has then been vapour-deposited Such a process is described, for example, in EP-A-0 244996.
It has now been found that if curable epoxy resin compositions filled with wollastonite and a quartz/kaolinite mixture are used, moulded materials or coatings having both good mechanical properties and high-gloss surfaces onto which metals can be vapour-deposited directly are obtained by curing.
The present invention thus relates to a curable epoxy resin composition comprising
(a) an epoxy resin having on average more than one epoxide group in the molecule,
(b) an epoxy resin curing agent in an amount sufficient for full curing of the epoxy resin,
(c) wollastonite having an average particle size of less than 100 &mgr;m in an amount of 10 to 350 parts by weight per 100 parts by weight of the sum of components (a) and (b),
(d) a quartz/kaolinite mixture having an average particle size of less than 100 &mgr;m in an amount of 10 to 350 parts by weight per 100 parts by weight of the sum of components (a) and (b), the content of components (c) and (d) together not being greater than 360 parts by weight, and, if appropriate,
(e) customary additives.
The epoxy resins customary in the epoxy resin industry can be used as epoxy resin (a) for the preparation of the epoxy resin compositions according to the invention. Examples of epoxy resins are:
I) Polyglycidyl and poly(&bgr;-methylglycidyl)esters obtainable by reaction of a compound having at least two carboxyl groups in the molecule and epichlorohydrin or &bgr;-methylepichlorohydrin. The reaction is advantageously carried out in the presence of bases.
Aliphatic polycarboxylic acids can be used as the compound having at least two carboxyl groups in the molecule. Examples of such polycarboxylic acids are oxalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid or dimerized or trimerized linoleic acid. However, it is also possible to employ cycloaliphatic polycarboxylic acids, for example tetrahydrophthalic acid, 4-methyltetrahydrophthalic acid, hexahydrophthalic acid or 4-methylhexahydrophthalic acid. Aromatic polycarboxylic acids, for example phthalic acid, isophthalic acid or terephthalic acid, can furthermore be used.
II) Polyglycidyl or poly(&bgr;-methylglycidyl)ethers obtainable by reaction of a compound having at least two free alcoholic hydroxyl groups and/or phenolic hydroxyl groups and epichlorohydrin or &bgr;-methylepichlorohydrin under alkaline conditions or in the presence of an acid catalyst with subsequent treatment with an 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-1,4diol, poly(oxytetramethylene) glycols, pentane-1,5-diol, hexane-1,6-diol, hexane-2,4,6-triol, glycerol, 1,1,1-trimethylolpropane, pentaerythritol or sorbitol and from polyepichlorohydrins. However, they are also derived, for example, from cycloaliphatic alcohols, such as 1,4-cyclohexanedimethanol, bis(4-hydroxycyclohexyl)methane or 2,2-bis(4-hydroxycyclohexyl)propane, or they have aromatic nuclei, such as N,N-bis(2-hydroxyethyl)aniline or p,p′-bis(2-hydroxyethylamino)diphenylmethane. The glycidyl ethers can also be derived from mononuclear phenols, for example from resorcinol or hydroquinone, or they are based on polynuclear phenols, such as, for example, bis(4-hydroxyphenyl)methane, 4,4′-dihydroxybiphenyl, bis(4-hydroxyphenyl) sulfone, 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane and 2,2-bis(3,5)bromo-4-hydroxyphenyl)propane, and from 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, such as, for example, 4-chlorophenol, 2-methylphenol or 4-tert-butylphenol, or by condensation with bisphenols such as those of the type as defined above.
III) Poly(N-glycidyl) compounds obtainable by dehydrochlorination of the reaction products of epichlorohydrin with amines which have at least two amine hydrogen atoms. These amines are, for example, aniline, n-butylamine, bis(4-aminophenyl)methane, m-xylylenediamine or bis(4-methylaminophenyl)methane.
However, the poly(N-glycidyl) compounds also include triglycidyl isocyanurate, N,N′-diglycidyl derivatives of cycloalkyleneureas, such as ethyleneurea or 1,3-propyleneurea, and diglycidyl derivatives of hydantoins, such as of 5,5-dimethylhydantoin.
IV) Cycloaliphatic epoxy resins, for example bis(2,3-epoxycyclopentyl) ether, 2,3-epoxy-cyclopentyl glycidyl ether, 1,2-bis(2,3-epoxycyclopentyloxy)ethane or 3,4-epoxy-cyclohexylmethyl 3′,4′-epoxycyclohexanecarboxylate.
However, epoxy resins in which the 1,2-epoxide groups are bonded to different heteroatoms or functional groups can also be used; these compounds include, for example, the N,N,O-triglycidyl derivative of 4-aminophenol, the glycidyl ether-glycidyl ester of salicylic acid, N-glycidyl-N′-(2-glycidyloxypropyl)-5,5-dimethylhydantoin or 2-glycidyloxy-1,3-bis(5,5-dimethyl-1-glycidylhydantoin-3-yl)propane.
An aromatic epoxy resin, i.e. an epoxy compound which contains one or more aromatic rings in the molecule, is preferably used for the preparation of the epoxy resin compositions according to the invention.
In particular, a bisphenol diglycidyl ether or an epoxy-novolak resin, particularly preferably an epoxyphenol- or an epoxycresol-novolak resin, is used for the preparation of the epoxy resin compositions according to the invention.
The curing agents customary in the epoxy resin industry, for example polycarboxylic acids and anhydrides thereof, dicyandiamide, polyamines, polyaminoamides, adducts containing amino groups, aliphatic or aromatic polyols or curing agents having a catalytic action, can be employed as the epoxy resin curing agent (b) for the epoxy resin compositions according to the invention.
Suitable polycarboxylic acids for curing the epoxy resin compositions according to the invention are, for example, aliphatic polycarboxylic acids, such as maleic acid, oxalic acid, succinic acid, nonyl- or dodecylsuccinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid or dimerized or trimerized linoleic acid, cycloaliphatic polycarboxylic acids, such as, for example, tetrahydrophthalic acid, methylendomethylenetetrahydrophthalic acid, hexachloroendomethylenetetrahydrophthalic acid, 4-methyltetrahydrophthalic acid, hexahydrophthalic acid or 4-methylhexahydrophthalic acid, or aromatic polycarboxylic acids, such as, for example, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid or benzophenone-3,3′,4,4′-tetracarboxylic acid, and the anhydrides of the polycarboxylic acids mentioned.
Polyamines which can be employed for curing the abovementioned epoxy resin compositions are aliphatic, cycloaliphatic, aromatic or heterocyclic amines, such as, for example, ethylenediamine, propane-1,2-diamine, propane-1,3-diamine, N,N-diethylethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, N-(2-hydroxyethyl)-, N-(2-hydroxypropyl)- and N-(2-cyanoethyl)diethyltriamine,
Awe Jens
Beer Helmut
Endlich Wilhelm
LandOfFree
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