Methods for controlling hardness of styrene-butadiene block copolymers

Patent metadata

Field	Value
Publication number	US-2016264759-A1
Application number	US-201514645841-A
Country	US
Kind code	A1
Filing date	Mar 12, 2015
Priority date	Mar 12, 2015
Publication date	Sep 15, 2016
Grant date	—

Abstract

Methods for controlling properties of a conjugated diene monovinylarene block copolymer using a modifier during polymerization are disclosed. For instance, the Shore A hardness of the copolymer can be decreased via the addition of the modifier compound.

First claim

1 . A method of controlling a conjugated diene monovinylarene copolymerization reaction, the method comprising:
(i) contacting a monovinylarene monomer, a conjugated diene monomer, and an initiator in a predetermined sequence under polymerization conditions in a polymerization reactor system, and thereafter coupling and/or terminating to form a conjugated diene monovinylarene block copolymer; wherein the predetermined sequence comprises a dual charge of the monovinylarene monomer and the conjugated diene monomer; and (ii) introducing a modifier into the polymerization reactor system before the dual charge to control hardness of the copolymer, wherein the hardness of the copolymer decreases as an amount of the modifier introduced into the polymerization reactor system increases.

2 . The method of claim 1 , wherein the modifier comprises an amine, a metal phenolate, a metal sulfonate, an ether, an alkali metal alkoxide, or a combination thereof.

3 . The method of claim 1 , wherein the modifier comprises tetrahydrofuran (THF).

4 . The method of claim 1 , wherein the modifier comprises potassium tert-amylate (KTA).

5 . The method of claim 1 , wherein an amount of the modifier introduced into the polymerization reactor system is in a range from about 1:250 to about 1:10,000, based on the total moles of the modifier to the total moles of the monovinylarene monomer and the conjugated diene monomer.

6 . The method of claim 1 , wherein:
the monovinylarene monomer is styrene; and the conjugated diene monomer is a butadiene.

7 . The method of claim 6 , wherein a kink resistance of tubing produced from the copolymer of step (ii) and tested in accordance with DIN EN 13868 is in a range from about 10 to about 32 mm.

8 . (canceled)

9 . The method of claim 8 , wherein:
the conjugated diene monovinylarene block copolymer is a styrene butadiene block copolymer; a Shore A hardness of the copolymer is in a range from about 20 to about 95; and an amount of the modifier introduced into the polymerization reactor system is in a range from about 1:500 to about 1:5,000, based on the total moles of the modifier to the total moles of the monovinylarene monomer and the conjugated diene monomer.

10 . The method of claim 9 , wherein:
a pellet blocking force of the copolymer increases as the amount of the modifier introduced into the polymerization reactor system increases; the copolymer has from about 55 to about 85 wt. % monovinylarene monomer content, based on the total weight of the copolymer; and the conjugated diene monovinylarene block copolymer contains from 3 to 8 blocks.

11 . The method of claim 1 , further comprising measuring the hardness, and adjusting an amount of the modifier introduced into the polymerization reactor system based on a difference between the measured hardness and a target hardness.

12 . The method of claim 1 , wherein the predetermined sequence comprises two or more dual charges, and the modifier is introduced into the polymerization reactor system before each dual charge.

13 . The method of claim 1 , wherein the block copolymer comprises from about 35 phm to about 80 phm monovinylarene monomer, and comprises polymer chains containing a block structure having formula (1):
S 1 —(SB) 1   (1); wherein:
S 1 is a monoblock of the monovinylarene monomer, wherein S 1 is from about 10 phm to about 45 phm of the copolymer; and (SB) 1 is a mixed block of the conjugated diene monomer and the monovinylarene monomer, wherein the monovinylarene monomer content is from 20 wt. % to 80 wt. %, based on the total weight of (SB) 1 .

14 . A process for producing a conjugated diene monovinylarene block copolymer with a target hardness, the process comprising:
(a) contacting a monovinylarene monomer, a conjugated diene monomer, and an initiator in a predetermined sequence under polymerization conditions in a polymerization reactor system, and thereafter coupling and/or terminating to form the copolymer; wherein the predetermined sequence comprises a dual charge of the monovinylarene monomer and the conjugated diene monomer; and (b) controlling an amount of a modifier introduced into the polymerization reactor system to produce the copolymer with the target hardness.

15 . The process of claim 14 , wherein:
a Shore A hardness of the copolymer decreases as the amount of the modifier introduced into the polymerization reactor system increases; and a target Shore A hardness is in a range from about 20 to about 95.

16 . The process of claim 14 , wherein the copolymer is a styrene butadiene block copolymer.

17 . The process of claim 16 , wherein the copolymer has a Mn in a range from about 10,000 to about 500,000 g/mol and a MFR in a range from about 1 to about 30 g/10 min; and a target Shore A hardness is in a range from about 35 to about 90.

18 . The process of claim 17 , wherein the copolymer has from about 55 to about 85 wt. % monovinylarene monomer content, based on the total weight of the copolymer.

19 . The process of claim 14 , wherein:
the monovinylarene monomer is styrene; the conjugated diene monomer is a butadiene; and a target Shore A hardness is in a range from about 40 to about 95.

20 . The process of claim 19 , wherein:
the copolymer has from about 50 to about 95 wt. % monovinylarene monomer content, based on the total weight of the copolymer; and a pellet blocking force of the copolymer decreases as the amount of the modifier introduced into the polymerization reactor system decreases.

21 . The method of claim 1 , wherein a Shore A hardness of the copolymer is in a range from about 35 to about 90.

Assignees

• Chevron Phillips Chemical Co Lp

Inventors

• Zhou Jinping Joe

Classifications

• C08K5/1535 Primary

  Five-membered rings · CPC title

• C08K5/057

  Metal alcoholates {(metal enolates C08K5/0091)} · CPC title

• C08F297/044 Primary

  using a coupling agent · CPC title