Flame retardant resins comprising phosphorus containing flame retardants

1. A flame retardant resin composition comprising

a) a cyanate resin, bismaleimide resin, polyimide resin, phenolic resin, furan resin, xylene formaldehyde resin, ketone formaldehyde resin, urea resin, melamine resin, aniline resin, alkyd resin, unsaturated polyester resin, diallyl phthalate resin, triallyl cyanate resin, triazine resin, polyphenylene ether resin, benzocyclobutene resin, or benzooxazine resin,

b) from 1% to 60%, by weight based on the total weight of the flame retardant resin composition, of a flame retardant material comprising products of thermal conversion of one or more than one compound of formula (I) before incorporation into the resin of component a), said products being obtained by a process comprising heating at temperatures of about 200° C. or higher from about 0.01 hour to about 20 hours one or more than one compound of formula (I)

wherein

R is C 1-12 alkyl, C 6-10 aryl, C 7-18 alkylaryl, or C 7-18 arylalkyl, wherein said alkyl, aryl, alkylaryl, or arylalkyl are unsubstituted or are substituted by halogen, hydroxyl, amino, C 1-4 alkylamino, di-C 1-4 alkylamino, C 1-4 alkoxy, carboxy or C 2-5 alkoxycarbonyl;

M is a metal,

y is a number of from 1 to 4 so that M (+)y is a metal cation where (+)y represents the charge formally assigned to the cation, and p is a number of from 1 to 4, and

c) a curing agent,

wherein the flame retardant resin exhibits a V-1 or V-0 rating using the “Underwriters Laboratory” test method UL 94.

2. The flame retardant resin composition according to claim 1 wherein the flame retardant material (b) comprises at least one compound corresponding to formula (IV) having more than one than one R group and/or more than one M group,

wherein R is as defined above, q is 1, 2 or 3, r is 0, 1 or 2, y is 1, 2, 3, or 4, and n is 1 or 2, provided that 2(q)+r=n(y),

and is obtained by a process comprising:

i) preparing an intermediate salt complex by treating one or more phosphonic acid compound with one or more appropriate metal compound to give an intermediate salt complex corresponding to formula (I) comprising multiple values for R and/or M, and then heating the intermediate salt complex at temperatures of about 200° C. or higher for about 0.01 hour to about 20 hours;

or

ii) preparing an intimate salt mixture by combining two or more individual metal phosphonic acid salts of formula (I) which have differing values for R and/or M, and then heating the intimate salt mixture at temperatures of about 200° C. or higher for about 0.01 hour to about 20 hours.

3. The flame retardant resin composition according to claim 1 wherein M in formula (I) is Li, K, Na, Mg, Ca, Ba, Zn, Zr, B, Al, Si, Ti, Sn or Sb.

4. The flame retardant resin composition according to claim 1 wherein M in formula (I) is Al or Ca.

5. The flame retardant resin composition according to claim 1 wherein in formula (I) R is unsubstituted C 1-6 alkyl, C 6 aryl, C 7-10 alkylaryl, or C 7-12 arylalkyl.

6. The flame retardant resin composition according to claim 1 further comprising d) one or more compounds selected from the group consisting of additional flame retardants, synergists and flame retardant adjuvants.

7. The flame retardant resin composition according to claim 1 wherein the curing agent comprises a phenolic cross linker, a diamine, a polyamine, a dicyandiamide or a substituted dicyandiamide.

8. The flame retardant resin composition according to claim 1 further comprising one or more epoxy resins.

9. The flame retardant resin composition according to claim 8 wherein the one or more epoxy resins comprise an epoxy novolac resin.

10. A laminate comprising a cured flame retardant resin composition according to claim 1 .