US 4,055,520 A · Polyphosphazene blends

Abstract

Polyphosphazene blends and foams thereof are described. The blends comprise of at least one polyphosphazene copolymer having a Young's Modulus of up to about 5.times.10.sup.8 dynes/cm.sup.2 and at least one polyphosphazene homopolymer or copolymer having a Young's Modulus of at least about 5.times.10.sup.8 dynes/cm.sup.2. The copolymers used to prepare the blends comprise randomly repeating units represented by the formulas ##STR1## wherein R.sub.1 and R.sub.2 are the same or different and are hydrogen, a C.sub.1 - C.sub.10 linear or branched alkyl radical, or a C.sub.1 - C.sub.4 linear or branched alkoxy radical substituted on any sterically permissible position on the phenoxy group, with the proviso that when R.sub.2 is alkoxy, R.sub.1 and R.sub.2 are different. The blends of this invention can be formed into sheets or films, or into flexible or semi-rigid foams. The blends are extremely fire retardant and produce low smoke loads, or essentially no smoke, when heated in an open flame.

Claims29

Dependent claims

The process of foaming a composition comprising a blend of at least one relatively elastomeric polyphosphazene copolymer having a Young's Storage Modulus in the range of 1.times.10.sup.6 to 5.times.10.sup.8 dynes/cm .sup.2 and having randomly repeating units represented by the formulas ##STR6## wherein R.sub.1 and R.sub.2 are the same or different and are hydrogen, a C.sub.1 -C.sub.10 linear or branched alkyl radical, or a C.sub.1 -C.sub.4 linear or branched alkoxy, with the proviso that when R.sub.2 is alkoxy, R.sub.1 and R.sub.2 are different;

with at least one relatively stiff or rigid polyphosphazene homopolymer or copolymer having a Young's Storage Modulus in the range of 5.times.10.sup.8 to 6.times.10.sup.10 dynes/cm.sup.2 and having randomly repeating units represented by the formulas ##STR7## wherein R.sub.1 and R.sub.2 are the same or different and are hydrogen, a C.sub.1 -C.sub.10 linear or branched alkyl radical, or a C.sub.1 -C.sub.4 linear or branched alkoxy, said relatively elastomeric copolymer:
relatively stiff or rigid homopolymer or copolymer in a ratio of from about 1:3 to about 3:1, wherein said blend is mixed with a chemical blowing agent and the mixture heated to a temperature sufficient to decompose said blowing agent.

A process of foaming a composition comprising a blend of a relatively elastomeric first polymer having the general formula

[NP(OC.sub.6 H.sub.4 -R.sub.1).sub.a (OC.sub.6 H.sub.4 -R.sub.2).sub.b (W).sub.c ].sub.n
wherein R.sub.1 and R.sub.2 are the same or different and are individually hydrogen, C.sub.1 -C.sub.10 linear or branched alkyl or C.sub.1 -C.sub.4 linear or branched alkoxy, with the proviso that when R.sub.2 is alkoxy, R.sub.1 and R.sub.2 are different;
W represents a monovalent radical containing a group capable of a crosslinking chemical reaction at moderate temperatures, said group being attached to a P atom by a -O- linkage;
n is from 20 to 2000;
c.gtoreq.o;
a+b+c=2;
the ratio of a:b is from about 1:6 to 6:1;
the ratio of c:(a+b) is less than about 1:5;
and the Young's Storage Modulus of said first polymer is in the range of 1.times.10.sup.6 to 5.times.10.sup.8 dynes/cm.sup.2 ;
with a relatively stiff or rigid second polymer having the general formula
[NP(OC.sub.6 H.sub.4 -R.sub.1).sub.a (OC.sub.6 H.sub.4 -R.sub.2).sub.b (W).sub.c ].sub.n
wherein R.sub.1 and R.sub.2 are the same or different and are individually hydrogen, C.sub.1 -C.sub.10 linear or branched alkyl or C.sub.1 -C.sub.4 linear or branched alkoxy;
W represents a monovalent radical containing a group capable of a crosslinking chemical reaction at moderate temperatures, said group being attached to a P atom by a -O- linkage;
n is from 20 to 2000;
c.gtoreq.o;
a+b+c=2;
the ratio of a:b is from about 1:6 to 6:1;
the ratio of c:(a+b) is less than about 1:5;
and the Young's Storage Modulus of said second polymer is in the range of 5.times.10.sup.8 to 6.times.10.sup.10 dynes/cm.sup.2 ;
the ratio of said first polymer to said second polymer ranging from about 1:3 to about 3:1, wherein said blend is mixed with a chemical blowing agent and the mixture heated to a temperature sufficient to decompose said blowing agent.

17 more elements

A foamed polymer blend comprised of a relatively elastomeric first polymer having the general formula

[NP(OC.sub.6 H.sub.4 -R.sub.1).sub.a (OC.sub.6 H.sub.4 -R.sub.2).sub.b (W).sub.c ].sub.n
wherein R.sub.1 and R.sub.2 are the same or different and are individually hydrogen, C.sub.1 -C.sub.10 linear or branched alkyl or C.sub.1 -C.sub.4 linear or branched alkoxy, with the proviso that when R.sub.2 is alkoxy, R.sub.1 and R.sub.2 are different;
W represents a monovalent radical containing a group capable of a crosslinking chemical reaction at moderate temperatures, said group being attached to a P atom by a -O- linkage;
n is from 20 to 2000;
c.gtoreq.o;
a+b+c=2;
the ratio of a:b is from about 1:6 to 6:1;
the ratio of c:(a+b) is less than about 1:5;
and the Young's Storage Modulus of said first polymer is in the range of 1.times.10.sup.6 to 5.times.10.sup.8 dynes/cm.sup.2 ;
and a second relatively stiff or rigid polymer having the general formula
[NP(OC.sub.6 H.sub.4 -R.sub.1).sub.a (OC.sub.6 H.sub.4 -R.sub.2).sub.b (W).sub.c ].sub.n
wherein R.sub.1 and R.sub.2 are the same or different and are individually hydrogen, C.sub.1 -C.sub.10 linear or branched alkyl or C.sub.1 -C.sub.4 linear or branched alkoxy;
W represents a monovalent radical containing a group capable of a crosslinking chemical reaction at moderate temperatures, said group being attached to a P atom by a -O- linkage;
n is from 20 to 2000;
c.gtoreq.o, a+b+c=2;
the ratio of a:b is from about 1:6 to 6:1;
the ratio of c:(a+b) is less than about 1:5;
and the Young's Storage Modulus of said second polymer is in the range of 5.times.10.sup.8 to 6.times.10.sup.10 dynes/cm.sup.2 ;
the ratio of said first polymer to said second polymer ranging from about 1:3 to about 3:1.

16 more elements

Dependencies are inferred from the claim text.

Polyphosphazene blends

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Polyphosphazene blends

Life of this patent

Abstract

Claims29