Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Patent
1999-09-16
2000-06-27
Powers, Fiona T.
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
528365, C07D49100
Patent
active
060808721
DESCRIPTION:
BRIEF SUMMARY
This invention relates to novel cycloaliphatic epoxy compounds. It further relates to a process for preparing such epoxy compounds, a cured epoxy resin derived therefrom, and a process for preparing such cured epoxy resin.
Cycloaliphatic epoxy resins are epoxy resins resulting from epoxidation of cycloaliphatic olefins. These resins usually exhibit better mechanical and electrical properties than the common glycidyl ether epoxy resins. Some of their properties, however, are not completely satisfactory. In particular they are very rigid and brittle and not as tough as one would wish.
It is a purpose of the present invention to provide cycloaliphatic epoxy resins which exhibit improved fracture-mechanical properties, in particular high toughness (as expressed by the critical stress intensity factor, K.sub.1C, and the specific fracture energy, G.sub.1C) as well as high strength.
According to the invention, this objective is accomplished by the cycloaliphatic epoxy compounds of the general formula ##STR2## wherein R.sup.1 and R.sup.2 are hydrogen atoms, or R.sup.1 and R.sup.2 taken together represent an epoxy group;
R.sup.3 and R.sup.4 are the same or different and each represents a hydrogen atom or a methyl group; and Q is a linear or branched alkanediyl group with 2 to 16 carbon atoms and with the proviso that the adjacent nitrogen and oxygen atoms are not attached to the same carbon atom.
Preferably, the residues R.sup.3 and R.sup.4 are hydrogen atoms.
According to the invention, the new cycloaliphatic epoxy compounds can be prepared by (i) reacting an acid or an ester of the general formula ##STR3## wherein R is hydrogen or a C.sub.1-6 -alkyl group, R.sup.1' and R.sup.2' are hydrogen atoms, or R.sup.1' and R.sup.2' taken together represent a direct bond between the adjacent carbon atoms, and R.sup.3 is a hydrogen atom or a methyl group, in the presence of a catalyst with a N-(hydroxyalkyl)-tetrahydrophthalimide of the general formula ##STR4## wherein R.sup.4 is hydrogen or a methyl group and Q is as described above, to form an unsaturated compound of the general formula ##STR5## wherein R.sup.1', R.sup.2', R.sup.3, R.sup.4 and Q are as defined above, and (ii) epoxidizing said unsaturated compound (IV) by reacting it with a peroxy compound.
The acids and esters (II) are known compounds. The tetrahydro- and hexahydrophthalic acids and anhydrides are commercially available. The esters are commercially available too or easily prepared from the corresponding acids or anhydrides.
Preferably the isobutyl esters are used as starting materials.
The N-(hydroxyalkyl)tetrahydrophthalimides (III) are known compounds and commercially available or easily prepared from the corresponding tetrahydrophthalic acids or anhydrides and the corresponding aminoalcohols H.sub.2 N--Q--OH. Preferably N-(hydroxyaLkyl)tetrahydrophthalimides (III) wherein Q is --(CH.sub.2).sub.n -- and n is a whole number from 2 to 16 are employed. Most preferably, Q is --(CH.sub.2).sub.2 --.
The first step, which is an esterification or a transesterification, may be performed in an inert solvent or, preferably, without solvent. Advantageously, the water or alcohol R--OH formed as a byproduct is distilled off during the reaction to shift the equilibrium in the desired direction. Standard catalysts (e. g. strong acids) may be used in this step.
As a peroxy compound, both organic and inorganic peroxy compounds may be used. Preferably peroxycarboxylic acids are used as peroxy compounds, monoperphthalic acid being especially preferred.
Hydrogen peroxide is also a preferred peroxy compound. When hydrogen peroxide is used, a phase transfer catalyst may be used. Examples of suitable phase transfer catalysts are described in: J Polym. Sci., Part A: Polym. Chem. 1993, 31, 1825-1938.
The epoxidation reaction is advantageously carried out in an inert solvent. Suitable inert solvents are, for example, alkyl esters, halogenated hydrocarbons, cycloaliphatic hydrocarbons, aromatic hydrocarbons or alcohols.
The cycloaliphatic epoxy compounds according to the invention
REFERENCES:
patent: 3369055 (1968-02-01), Salyer et al.
patent: 3450711 (1969-06-01), Megna et al.
Monte et al., Macromolecular Chemistry and Physics, vol. 196, No. 4, (1995), pp 1051-62.
Patent Abstracts Of Japan, vol. 4, No. 124, (C-023), (Sep. 2, 1980).
Storey et al., Journal of Polymer Science, Part A: Polymer Chemistry, vol. 31, No. 6, (1993), pp. 1825-1838.
Beisele Christian
Caramaschi Giuseppe
Fumagalli Carlo
Pirola Roberto
Lonza S.P.A.
Powers Fiona T.
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