Intrinsically non-blocking shrink sleeve material

Patent metadata

Field	Value
Publication number	US-11879059-B2
Application number	US-201816487211-A
Country	US
Kind code	B2
Filing date	Feb 19, 2018
Priority date	Feb 21, 2017
Publication date	Jan 23, 2024
Grant date	Jan 23, 2024

Abstract

Polymer compositions comprising stiff and tough star shaped styrene butadiene block-copolymers A1 and A2 can be used for making shrink films. Block copolymer A2 preferably has the structurewith hard blocks Se and Si, hard random copolymer blocks (B/S)Ae, soft random copolymer blocks (B/S)B coupled by a coupling agent X.

First claim

The invention claimed is:

1. A polymer composition comprising components (a), (b), and (c):
a) 45 to 100 wt.-% of component a) consisting of:
a1) 20 to 80 wt.-% of at least one star-shaped block copolymer A1 having:
two short branches consisting of a single copolymer block (B/S) Ai made from 65 to 95 wt.-% vinylaromatic monomers and 35 to 5 wt.-% dienes and having a glass transition temperature Tg A in the range from 40 to 90° C., and two long branches of the structure S t —[(B/S) A ] n -(B/S) Ai or [(B/S) A ] n -(B/S) Ai , linked (to one another via a coupling agent) by way of the inner blocks (B/S) Ai , where the block S t is made from 95 to 100 wt.-% of vinylaromatic monomers and 0 to 5 wt.-% of dienes; the block [(B/S) A ] n , consists of one or more different or identical copolymer blocks (B/S) A , each made from 65 to 95 wt.-% vinylaromatic monomers and 35 to 5 wt.-% dienes and have a glass transition temperature Tg A in the range from 40 to 90° C.; n is a regular number of at least 1, and the block (B/S) Ai is as defined above, wherein the block (B/S) Ai has a number average molar mass M n in the range of from 5000 to 15000 g/mol and the entire block [(B/S) A ] n has a number average molar mass M n of 50000 to 150000 g/mol; and

a2) 80 to 20 wt.-% of at least one star-shaped block copolymer A2, which has in essence two short branches of structure S e —(B/S) B and two long branches of structure (B/S) Ae —S i —(B/S) B , linked (to one another via a coupling agent) by way of the blocks (B/S) B ,
wherein the polymer blocks S e and S i are identical; the polymer blocks S e and S i are made from 95 to 100 wt.-% of vinylaromatic monomers and of from 0 to 5 wt.-% of dienes; the copolymer block (B/S) Ae is made from 65 to 95 wt.-% vinylaromatic monomers and 35 to 5 wt.-% dienes and has a glass transition temperature Tg A in the range from 40 to 90° C.; and the homo- or copolymer blocks (B/S) B are each made from 0 to 25 wt.-%, vinylaromatic monomers, and 100 to 75 wt.-%, dienes and have a glass transition temperature Tg B in the range from −90° to −60° C.;

b) 0 to 55 wt.-% of at least one further thermoplastic polymer TP other than block copolymers A1 and A2; and
c) 0 to 5 wt.-% of at least one additive or processing aid;
where the total amount of components (a) and, if present, (b) and/or (c) is 100% by weight, based on the entire polymer composition, and the glass transition temperature Tg is determined by DSC based on DIN EN ISO 11357-2:2014-07.

2. The polymer composition according to claim 1 , wherein component a) consists of a1) 25 to 50 wt.-%, block copolymer A1 and a2) 50 to 75 wt.-%, block copolymer A2.

3. The polymer composition according to claim 1 , wherein block copolymer A2 has a melt mass flow index (measured on a polymer melt at 220° C. and 5 kg load according to ISO 1133-1:2011) in the range of from 8 to 15 ml/10 min.

4. The polymer composition according to claim 1 , wherein the proportion of the entirety of all of the blocks (B/S) B (=soft phase) of block copolymer A2 is from 30 to 37 wt.-%.

5. The polymer composition according to claim 1 , wherein the block (B/S) B of block copolymer A2 is a copolymer block made from 1 to 25 wt.-%, vinylaromatic monomers and 99 to 75 wt.-% dienes.

6. The polymer composition according to claim 1 , wherein in block copolymer A2 the number average molar mass Mn of the block (B/S) B is 5000 to 50000 g/mol; Mn of the block (B/S) Ae is 30000 to 100000 g/mol; and Mn of the polymer blocks S e or S i is in the range from 5000 to 30000 g/mol.

7. The polymer composition according to claim 1 , wherein star shaped block copolymer A2 has the following structure:

where S e , S i , (B/S) Ae and (B/S) B are as defined above and X is a coupling center, which is formed by reaction of the living anionic polymer chain ends with a polyfunctional coupling agent.

8. The polymer composition according to claim 1 , wherein the copolymer blocks (B/S) A , (B/S) Ai , (B/S) Ae and (B/S) B of block copolymers A1 and A2 are composed of polymerized vinylaromatic monomers and of dienes with random distribution.

9. The polymer composition according to claim 1 , wherein the number-average molar mass Mn of the block S t of block copolymer A1 is in the range from 3000 to 8000 g/mol.

10. The polymer composition according to claim 1 , wherein the block [(B/S) A ] n of block copolymer A1 consists of 2 to 10 different copolymer blocks (B/S) A , where the blocks (B/S) A differ in their molar masses and/or in their vinylaromatic/diene ratio.

11. The polymer composition according to claim 1 , wherein the copolymer blocks (B/S) A , and/or (B/S) Ai of block copolymer A1 are made from 85 to 93 wt.-% of a vinylaromatic monomer and from 7 to 15 wt.-% of a diene.

12. The polymer composition according to claim 1 , wherein star shaped block copolymer A1 has the following structure:

where S t , and (B/S) Ai are as defined in claim 1 , (B/S) A1 and (B/S) A2 are two different copolymer blocks (B/S) A as defined in claim 1 , and X is a coupling center, which is formed by reaction of the living anionic polymer chain with a polyfunctional coupling agent.

13. A process for the preparation of the polymer composition according to claim 1 , comprising the step of melt mixing of component a) and optional components b) and/or c) by aid of a mixing apparatus at a temperature in the range of from 160° C. to 300° C.

14. A method of using the polymer composition according to claim 1 for the production of films.

15. Shrink film, produced from the polymer composition according to claim 1 .

16. Star-shaped block copolymer A2 according to claim 1 , wherein the star shaped block copolymer A2 has the following structure:

where S e , S i , (B/S) Ae and (B/S) B are as defined in claim 1 and X is a coupling center, which is formed by reaction of the living anionic polymer chain ends with a polyfunctional coupling agent, and the proportion of the entirety of all of the blocks (B/S) B (=soft phase) of block copolymer A2 is from 31 to 35 wt.-%.

17. A process for the preparation of block copolymer A2 according to claim 16 characterized by:
a) a double initiation,
b) a coupling step after the addition and polymerization of a diene and optionally a vinylaromatic monomer used for the preparation of homo- or copolymer block (B/S) B , and
c) the second initiation process placed before the addition and polymerization of the vinylaromatic monomer used for the preparation blocks S i and S e , wherein the molar ratio of the first and the second initiation is from 0.9:1 to 1.5:1.

Assignees

• Ineos Styrolution Group Gmbh

Inventors

• Verswyvel Michiel
• Niessner Norbert
• Wagner Daniel
• Schuster Michael
• Verlinden Geert
• Van-Den-Bossche Bart
• Knoll Konrad

Classifications

• C08L53/02 Primary

  of vinyl-aromatic monomers and conjugated dienes · CPC title

• C08J5/18

  Manufacture of films or sheets · CPC title

• C08J2353/02

  of vinyl aromatic monomers and conjugated dienes · CPC title

• C08J2453/02

  of vinyl aromatic monomers and conjugated dienes · CPC title

• C08L2203/162

  sealable films · CPC title