Bulk polymerization of silicone-containing copolymers

Patent metadata

Field	Value
Publication number	US-10465017-B2
Application number	US-201815879575-A
Country	US
Kind code	B2
Filing date	Jan 25, 2018
Priority date	Dec 17, 2008
Publication date	Nov 5, 2019
Grant date	Nov 5, 2019

Abstract

Methods for preparing silicone-containing polymers by essentially adiabatic polymerization methods are disclosed. The polymerization system includes free radically polymerizable monomers. The monomers include ethylenically unsaturated silicone-containing monomers and/or mercapto-functional silicones as well as additional free radically polymerizable monomers. The silicone-containing polymers are useful as adhesives or release materials.

First claim

What is claimed is:

1. A method comprising:
providing a first reaction mixture comprising:
a mercapto-functional silicone;
at least one ethylenically unsaturated monomer;
a chain transfer agent separate from the mercapto-funcitonal silicone; and
a thermal initiator;

deoxygenating the first reaction mixture;
heating the first reaction mixture to a temperature above the activation temperature of the thermal initiator;
allowing the first reaction mixture to polymerize under essentially adiabatic conditions to yield an at least partially polymerized mixture;
cooling the at least partially polymerized mixture;
adding an additional thermal initiator to the partially polymerized mixture to form a second reaction mixture;
deoxygenating the second reaction mixture;
heating the second reaction mixture to a temperature above the activation temperature of the additional thermal initiator;
allowing the second reaction mixture to polymerize under essentially adiabatic conditions to form a polymer.

2. The method of claim 1 , wherein the mercapto-functional silicone has the structure:
(R 1 ) 3-x (HSR 2 ) x Si—(OSiR 5 R 6 ) y —OSi(R 3 ) 3-q (R 4 SH) q

wherein each R 1 is independently an alkyl, aryl, alkaryl, alkoxy, alkylamino, hydroxyl, hydrogen, or fluoroalkyl group;
each R 2 is a divalent linking group;
each R 3 is an alkyl, aryl, alkaryl, alkoxy, alkylamino, hydroxyl, hydrogen, or fluoroalkyl group;
each R 4 is a divalent linking group;
each R 5 is an alkyl, aryl, alkaryl, alkoxy, alkylamino, hydroxyl, fluoroalkyl, hydrogen, or —ZSH, wherein Z is a divalent linking group;
each R 6 is an alkyl, aryl, alkaryl, alkoxy, alkylamino, hydroxyl, fluoroalkyl, hydrogen, or —ZSH, wherein Z is a divalent linking group;
x is an integer of 0-3;
y is an integer of 10 or greater; and
q is an integer of 0-3.

3. The method of claim 1 , wherein the mercapto-functional silicone has a number average molecular weight of from 2,000-20,000 grams/mole and from 1-20 mole % —CH 2 CH 2 CH 2 SH groups.

4. The method of claim 1 , wherein the mercapto-functional silicone has a number average molecular weight of from 5,000-10,000 grams/mole and from 2-4 mole % —CH 2 CH 2 CH 2 SH groups.

5. The method of claim 1 , wherein the ethylenically unsaturated monomer comprises an alkyl (meth)acrylate which as a homopolymer has a Tg above about 30° C.

6. The method of claim 5 , wherein the alkyl (meth)acrylate monomer comprises an alkyl (meth)acrylate with an alkyl chain having from 1-20 carbon atoms.

7. The method of claim 1 , further comprising the steps of:
isolating the polymer; and
coating the polymer on a substrate.

8. The method of claim 7 , wherein the coating step comprises hot melt coating, solvent coating or coextrusion.

9. The method of claim 7 , wherein the polymer comprises a release material and the substrate comprises a film or a tape backing.

10. The method of claim 8 , wherein the coating method comprises hot melt coating and the coating thickness is in the range from about 0.01 to about 2.5 micrometers.

11. The method of claim 1 , further comprising the steps of:
isolating the polymer;
blending the isolated polymer with a thermoplastic resin; and
hot melt coating or coextruding the blend.

12. The method of claim 11 , wherein the coating method comprises hot melt coating and the coating thickness is in the range from about 0.01 to about 2.5 micrometers.

Assignees

• 3M Innovative Properties Co

Inventors

• Sherman Audrey A
• Ellis Mark F
• Kumar Ramesh C
• Mackey Sonja S
• Peloquin Richard L
• Emslander Jeffrey O

Classifications

• C09J2451/00

  Presence of graft polymer · CPC title

• C09J7/381

  based on macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds · CPC title

• C08F220/06

  Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof · CPC title

• C08G77/442

  containing vinyl polymer sequences · CPC title

• C08G77/20

  containing silicon bound to unsaturated aliphatic groups · CPC title