Claims
- 1. A process for producing a solvent resistant block copolymer comprising (a) reacting in an anhydrous system a trimer of the formula,
- [(R) (R' CH.sub.2 CH.sub.2) SiO].sub.3
- in the presence of a solvent promoter selected from the class consisting of tetrahydrofuran, dioxane, dimethylformamide, dimethylsulfoxide, tetramethyl urea, and a catalyst which is a dilithium compound selected from the class of compounds of the formula, ##STR6## and compounds of the formula, ##STR7## where R.sup.2 and R.sup.3 are selected from the class consisting of hydrogen and lower alkyl radicals of 1 to 8 carbon atoms, and then adding a trimer of the formula,
- [(C.sub.6 H.sub.5).sub.2 SiO].sub.3
- and completing the reaction.
- 2. The process of claim 1 wherein the reaction is carried out in two reaction periods wherein the first reaction period comprises reacting the fluorosilicone trimer at a temperature in the range of 55.degree. C to 85.degree. C for a period of time varying from 0.5 to 4 hours and then adding the diphenyl trimer in a second reaction period comprising reacting the trimers at a temperature in the range of 85.degree. to 180.degree. C for a period of time varying from 1 to 8 hours.
- 3. The process of claim 2 wherein in said second reaction period the solvent promoter is removed and there is added a high boiling solvent to complete the polymerization in said second reaction period.
- 4. The process of claim 3 wherein said high boiling solvent is selected from the class consisting of dichlorobenzene and the dimethoxyether of diethylene glycol and phenylether.
- 5. The process of claim 1 wherein after said second reaction period further comprising neutralizing said catalyst with a neutralizing agent selected from the class consisting of water, acetic acid, and an aliphatic alcohol and stripping off the solvent.
- 6. The process of claim 1 wherein the catalyst is utilized at a concentration of 0.7 to 8.0 millimoles, per mole of trimer reactants.
- 7. The process of claim 1 wherein the promoter solvent utilized is at least of sufficient quantity of dissolve the reactants.
- 8. The process of claim 1 wherein in step (a) there is also reacted a cyclictrisiloxane of the formula,
- [R Vi SiO].sub.3
- where R is an alkyl radical of 1 to 8 carbon atoms and Vi is vinyl.
Parent Case Info
This application is a continuation of parent application Ser. No. 621,032 filed Oct. 9, 1975 now U.S. Pat. No. 4,028,338.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
3337497 |
Bostick |
Aug 1967 |
|
3503926 |
Saylor |
Mar 1970 |
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Continuations (1)
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Number |
Date |
Country |
Parent |
621032 |
Oct 1975 |
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