Halogen free benzoxazine based curable compositions for high T
A method for forming a halogen-free curable composition containing a benzoxazine monomer, at least one epoxy resin, a catalyst, a toughening agent and a solvent. The halogen-free curable composition is especially suited for use in automobile and aerospace applications since the composition, upon curing, produces a composite having a high glass transition temperature.
1. A method for producing a halogen-free curable composition comprising mixing together:
(a) a benzoxazine monomer of the formula (I)
wherein each R is, independently from one another, allyl, unsubstituted or substituted phenyl, unsubstituted or substituted C 1 -C 8 -alkyl or unsubstituted or substituted C 3 -C 8 cycloalkyl;
(b) at least one epoxy resin;
(c) 5.7-10 parts by weight per 100 parts by weight of the composition of a catalyst selected from tetraphenolethane;
(d) 5.7-10 parts by weight per 100 parts by weight of a toughening agent of the formula (II)
wherein m is 1 or 2, n is 2 to 6, R 0 is an n-valent radical of an elastomeric prepolymer after the removal of the terminal isocyanate, amino or hydroxyl groups, the elastomeric prepolymer being soluble or dispersible in epoxy resin, X and Y independently of one another are —O— or —NR 3 —, at least one X or Y being —NR 3 —, R 2 is an m+1-valent radical of polyphenol or aminophenol after the removal of the phenolic hydroxyl group(s) and optionally of the amino group, and R 3 is hydrogen, C 1 -C 6 alkyl or phenol; and
(e) a solvent
to produce the halogen-free curable composition.
2. The method of claim 1 further comprising mixing in at least one of reinforcement fibers, micro or hollow spheres, plasticizers, carbon black, graphite, dyestuffs, or metal powders.
3. A halogen-free curable composition produced according to the method of claim 1 .
4. A method of forming an article comprising:
(a) applying on a first substrate a halogen-free curable composition comprising
(i) a benzoxazine monomer of the formula (I)
wherein each R is, independently from one another, allyl, unsubstituted or substituted phenyl, unsubstituted or substituted C 1 -C 8 -alkyl or unsubstituted or substituted C 3 -C 8 cycloalkyl;
(ii) at least one epoxy resin;
(iii) 5.7-10 parts by weight per 100 parts by weight of the composition of a catalyst selected from tetraphenolethane;
(iv) 5.7-10 parts by weight per 100 parts by weight of a toughening agent of the formula (II)
wherein m is 1 or 2, n is 2 to 6, R 0 is an n-valent radical of an elastomeric prepolymer after the removal of the terminal isocyanate, amino or hydroxyl groups, the elastomeric prepolymer being soluble or dispersible in epoxy resin, X and Y independently of one another are —O— or —NR 3 —, at least one X or Y being —NR 3 —, R 2 is an m+1-valent radical of polyphenol or aminophenol after the removal of the phenolic hydroxyl group(s) and optionally of the amino group, and R 3 is hydrogen, C 1 -C 6 alkyl or phenol; and
(v) a solvent;
(b) adjoining a second substrate to the first substrate; and
(c) heating the halogen-free curable composition and substrates at a temperature greater than 150° C. to adhere the substrates together and form the article.
5. A container comprising a halogen-free curable composition wherein the halogen-free curable composition comprises
(a) a benzoxazine monomer of the formula (I)
wherein each R is, independently from one another, allyl, unsubstituted or substituted phenyl, unsubstituted or substituted C 1 -C 8 -alkyl or unsubstituted or substituted C 3 -C 8 cycloalkyl;
(b) at least one epoxy resin;
(c) 5.7-10 parts by weight per 100 parts by weight of the composition of a catalyst selected from tetraphenolethane;
(d) 5.7-10 parts by weight per 100 parts by weight of a toughening agent of the formula
wherein m is 1 or 2, n is 2 to 6, R 0 is an n-valent radical of an elastomeric prepolymer after the removal of the terminal isocyanate, amino or hydroxyl groups, the elastomeric prepolymer being soluble or dispersible in epoxy resin, X and Y independently of one another are —O— or —NR 3 —, at least one X or Y being —NR 3 —, R 2 is an m+1-valent radical of polyphenol or aminophenol after the removal of the phenolic hydroxyl group(s) and optionally of the amino group, and R 3 is hydrogen, C 1 -C 6 alkyl or phenol; and
(e) a solvent.