Polymer compositions and hot-melt adhesives formed therefrom
Predominately bio-sourced polymer compositions that may be used as hot-melt adhesives are disclosed herein. The polymer compositions may contain a polymer that has the following structure: G 1 and G 2 are independently (CH 2 ) x . Variable x is an integer ranging between 1 and 10. Variable y is an integer ranging between about 50 and about 500. Variable z is an integer ranging between about 100 and about 600. Variable n is an integer ranging between about 5 and about 10,000. X is H, a functionalized alkylene polymer block containing alcohol functional groups, or a mixture thereof. Y is H, an acyl group, a functionalized alkylene polymer containing carboxylic acid functional groups, or a mixture thereof.
1. A polymer composition comprising:
a polymer comprising a lactic acid block and an aliphatic polyester block, the polymer having a structure of:
wherein G 1 and G 2 are independently (CH R ) x , R is an alkyl group or H, and x is an integer ranging between 1 and 10;
wherein y is an integer ranging between 50 and 500;
wherein z is an integer ranging between 100 and 600;
wherein n is an integer ranging between 5 and 10,000;
wherein X is H, a functionalized alkylene polymer block containing alcohol functional groups, or a mixture thereof; and
wherein Y is H, an acyl group, a functionalized alkylene polymer containing carboxylic acid functional groups, or a mixture thereof.
2. The polymer composition of claim 1 , wherein the lactic acid block contains L-lactic acid.
3. A method comprising:
combining a lactic acid block and an aliphatic polyester block, the lactic acid block having a structure of
and the aliphatic polyester block having a structure of
and
reacting the lactic acid block and the aliphatic polyester block to form the polymer of claim 1 ;
wherein G 1 and G 2 are independently (CH R ) x , R is an alkyl group or H, and x is an integer ranging between 1 and 10;
wherein y is an integer ranging between about 50 and 500;
wherein z is an integer ranging between about 100 and 600;
wherein X is H, a functionalized alkylene polymer block containing alcohol functional groups, or a mixture thereof; and
wherein Y is H, an acyl group, a functionalized alkylene polymer containing carboxylic acid functional groups, or a mixture thereof.
4. A hot melt adhesive including:
a polymer comprising a lactic acid block and an aliphatic polyester block, the polymer having a structure of:
wherein G 1 and G 2 are independently (CH R ) x , R is an alkyl group or H, and x is an integer ranging between 1 and 10;
wherein y is an integer ranging between 50 and 500;
wherein z is an integer ranging between 100 and 600;
wherein n is an integer ranging between 5 and 10,000;
wherein X is H, a functionalized alkylene polymer block containing alcohol functional groups, or a mixture thereof; and
wherein Y is H, an acyl group, a functionalized alkylene polymer containing carboxylic acid functional groups, or a mixture thereof.
5. The hot melt adhesive of claim 4 , wherein the lactic acid block contains L-lactic acid.
6. The hot-melt adhesive of claim 4 consisting of the polymer and optionally one or more additives.
7. The hot melt adhesive of claim 4 having a viscosity of 800 to 3000 cPs at 290° F.
8. The hot melt adhesive of claim 4 having less than 10% drop in viscosity after storage for 24 hours at 290° F.
9. The hot melt adhesive of claim 4 having an open time of 5 seconds or more.
10. A package comprising two substrates bonded together by the hot melt adhesive of claim 4 .
11. The hot melt adhesive of claim 4 having a viscosity of 4000 to 5000 cPs at 290° F.
12. The hot melt adhesive of claim 4 having a drop in viscosity after storage for 24 hours at 290° F. from about 10% to about 30%.
13. The polymer composition of claim 1 , wherein Y is an acyl group having from 2 to 20 carbon atoms.
14. The polymer composition of claim 1 , wherein Y is a propionyl group.
15. The hot melt adhesive of claim 4 , wherein Y is an acyl group having from 2 to 20 carbon atoms.
16. The hot melt adhesive of claim 4 , wherein Y is a propionyl group.