Monovinylarene conjugated diene block copolymer compositions for shrinkable films

1. A block copolymer comprising:

a monovinylarylene and a conjugated diene coupled block copolymer;

a random mixed block of monovinylarylene and conjugated diene, wherein the random mixed block comprises 4-9 times as much monovinylarylene as conjugated diene;

wherein a 2 mil film of the block copolymer oriented at 80° C. or less exhibits the following properties:

at least 50% shrinkage when immersed for 30 seconds in an oil bath at 80° C.; and

a natural shrinkage of no more than 5%;

wherein the block copolymer comprises an initially formed block which is a monovinylarylene block that is 15-30 wt % of the block copolymer; and

wherein the block copolymer comprises 20-30 wt % conjugated diene.

2. The block copolymer of claim 1 , wherein a 2 mil film of the block copolymer oriented at 80° C. or less has a haze of no more than 5%.

3. The block copolymer of claim 1 , wherein a 2 mil film of the block copolymer oriented at 80° C. or less has a shrinkage at 100° C. of at least 70%.

4. The block copolymer of claim 1 , wherein a 2 mil film of the block copolymer oriented at 80° C. or less has a shrinkage at 100° C. of at least 75%.

5. The block copolymer of claim 1 , wherein the block copolymer is oriented at a temperature of 75° C. or less.

6. The block copolymer of claim 1 , wherein the block copolymer is oriented at a temperature of 70° C. or less.

7. The block copolymer of claim 1 , wherein the monovinylarylene is styrene and the conjugated diene is 1,3-butadiene.

8. The block copolymer of claim 1 , wherein the block copolymer is formed through a charge order: i-A-B-C-CA, where

“i” is a polymerization initiator charge;

“A” is a monovinylarylene charge;

“B” is a conjugated diene charge;

“C” is a mixed charge of monovinylarylene and conjugated diene polymerized under polymerization conditions that result in the random mixed block of monovinylarylene and conjugated diene; and

“CA” is a coupling agent.

9. The block copolymer of claim 1 , wherein the block copolymer is formed through a charge order: i-A-C-B-CA, where

“i” is a polymerization initiator charge;

“A” is a monovinylarylene charge;

“B” is a conjugated diene charge;

“C” is a mixed charge of monovinylarylene and conjugated diene polymerized under polymerization conditions that result in the random mixed block of monovinylarylene and conjugated diene; and

“CA” is a coupling agent.

10. The block copolymer of claim 1 , wherein the block copolymer is formed through a charge order: i-A-i-C-B-CA, where

“i” is a polymerization initiator charge;

“A” is a monovinylarylene charge;

“B” is a conjugated diene charge;

“C” is a mixed charge of monovinylarylene and conjugated diene polymerized under polymerization conditions that result in the random mixed block of monovinylarylene and conjugated diene; and

“CA” is a coupling agent.

11. A block copolymer comprising:

a monovinylarylene and a conjugated diene coupled block copolymer;

a random mixed block of monovinylarylene and conjugated diene, wherein the mixed block comprises 4-9 times as much monovinylarylene as conjugated diene; and

an initially formed block which is a monovinylarylene block that is 15-30 wt % of the block copolymer;

wherein an oriented 2 mil film of the block copolymer oriented at 100° C. or less exhibits the following properties:

less than 10% shrinkage when immersed for 30 seconds in an oil bath at 70° C.; and

at least 70% shrinkage when immersed for 30 seconds in an oil bath at 100° C.; and

wherein the block copolymer comprises 20-30 wt % conjugated diene.

12. The block copolymer of claim 11 , wherein a 2 mil film of the block copolymer oriented at 100° C. or less has a haze of no more than 5%.

13. The block copolymer of claim 11 , wherein a 2 mil film of the block copolymer oriented at 100° C. or less has a natural shrinkage of no more than 5%.

14. The block copolymer of claim 11 , wherein the block copolymer is oriented at a temperature of 70° C. or less.

15. The block copolymer of claim 11 , wherein the monovinylarylene is styrene and the conjugated diene is 1,3-butadiene.

16. The shrink film of claim 11 , wherein the block copolymer is formed through a charge order: i-A-C-B-CA where

“i” is a polymerization initiator charge;

“A” is a monovinylarylene charge;

“B” is a conjugated diene charge;

“C” is a mixed charge of monovinylarylene and conjugated diene polymerized under polymerization conditions that result in the random mixed block of monovinylarylene and conjugated diene; and

“CA” is a coupling agent.

17. The shrink film of claim 11 , wherein the block copolymer is formed through a charge order: i-A-i-C-B-CA, where

“i” is a polymerization initiator charge;

“A” is a monovinylarylene charge;

“B” is a conjugated diene charge;

“C” is a mixed charge of monovinylarylene and conjugated diene polymerized under polymerization conditions that result in the random mixed block of monovinylarylene and conjugated diene; and

“CA” is a coupling agent.

18. A block copolymer comprising a monovinylarylene and a conjugated diene;

wherein the block copolymer comprises an initially formed block which is a monovinylarylene block that is 15-30 wt % of the block copolymer;

wherein the block copolymer comprises a random mixed block of monovinylarylene and conjugated diene, wherein the mixed block comprises 4-9 times as much monovinylarylene as conjugated diene;

wherein the block copolymer comprises 20-30 wt % conjugated diene;

wherein the block copolymer is coupled;

wherein a 2 mil film of the block copolymer oriented at a temperature of at least 80° C. exhibits the following properties:

less than 17% shrinkage when immersed for 30 seconds in an oil bath at 70° C.;

at least 42% shrinkage when immersed for 30 seconds in an oil bath at 80° C.; and

at least 73% shrinkage when immersed for 30 seconds in an oil bath at 100° C.