Block copolymer, method of making the same, diamine precursors of the same, method of making such diamines and end products comprising the block copolymer

• US 5,512,650 A
• Filed: 07/21/1993
• Issued: 04/30/1996
• Est. Priority Date: 06/20/1986
• Status: Expired due to Term

• Current Assignee: 3M Company
• Original Assignee: 3M Company
• Inventors: Hoffman, Jerome J., Mazurek, Mjeczyslaw H., Wiederholt, Gary T., Tushaus, Leonard A., Leir, Charles M., Sherman, Audrey A., Bronn, William R.
• Primary Examiner(s): DEAN JR, RALPH H
• Application Number:
  US08/095,284
• Time in Patent Office: 1,014 Days
• Field of Search: 528/14, 528/22, 528/37, 528/38
• US Class Current: 528/14
• CPC Class Codes: C08G 18/61 Polysiloxanes
• CPC Class Codes: C08G 2170/40 Compositions for pressure-sensitive adhesives
• CPC Class Codes: C08G 77/26 nitrogen-containing groups
• CPC Class Codes: C08G 77/458 containing polyurethane sequences

Abstract

Block copolymers having a repeating unit comprised of polysiloxane and urea segments are prepared by copolymerizing certain diaminopolysiloxanes with diisocyanates. The invention also provides novel diaminopolysiloxanes useful as precursors in the preparation of the block copolymers and methods of making such diaminopolysiloxanes. Pressure sensitive adhesive compositions comprising the block copolymer are also provided as are sheet materials coated with the same.

Claims

1. A method of making an organopolysiloxane diamine having a number average molecular weight greater than 2000 and having less than or equal to about 0.010 weight % silanol impurities, comprising the steps of:

(a) forming a mixture consisting essentially of

(i) an amine functional endblocker represented by the formula IX ##STR11## wherein;

Y is selected from the group consisting of alkylene radicals comprising about 1 to about 10 carbon atoms, aralkyl radicals, and aryl radicals;

D is selected from the group consisting of hydrogen, an alkyl radical of about 1 to about 10 carbon atoms, and phenyl;

R is at least 50% methyl with a balance of the 100% of all R radicals being selected from the group consisting of a monovalent alkyl radical having 2 to 12 carbon atoms, substituted alkyl radical having from 1 to 12 carbon atoms, a vinyl radical, a phenyl radical, and a substituted phenyl radical; and

x represents an integer of about 1 to about 150; and

(ii) sufficient cyclic siloxane to obtain said organopolysiloxane diamine having a number average molecular weight greater than about 2000;

(b) removing any volatile contaminants from the mixture;

(c) heating the mixture to about 100°

to about 160°

C. under an inert atmosphere;

(d) adding a catalytic amount of a compound selected from the group consisting of cesium hydroxide, rubidium hydroxide, cesium silanolates, rubidium silanolates, cesium polysiloxanolates, rubidium polysiloxanolates, and mixtures thereof, to the mixture which has been heated;

(e) continuing the reaction until substantially all of said amine functional endblocker is consumed;

(f) terminating the reaction by the addition of a volatile organic acid to form a mixture of an organopolysiloxane diamine having greater than about 0.010 weight % silanol impurities and one or more of the following;

a cesium salt of the organic acid, a rubidium salt of the organic acid, both a cesium salt of the organic acid and a rubidium salt of the organic acid;

wherein a molar excess of organic acid is added in relation to the compound of element (d);

(g) condensing under reaction conditions a sufficient amount of said silanol impurities to form an organopolysiloxane diamine having less than or equal to about 0.010 weight % of silanol impurities; and

(h) optionally removing said salt.

2. The method of claim 1 wherein the endblocker has greater than about 0.010 weight % silanol impurities.

3. The method of claim 1 wherein the endblocker has less than or equal to about 0.010 weight % of silanol impurities.

4. The method of claim 1 wherein said organopolysiloxane diamine having a number average molecular weight greater than about 5000.

5. The method of claim 1 wherein x represents an integer of about 1 to about 70 and Y is selected from the group consisting of --CH₂ CH₂ CH₂ -- and --CH₂ CH₂ CH₂ CH₂ --.

6. The method of claim 1 wherein about 0.005 to about 0.3 weight percent of the compound of element (a)(iii) is used based upon the total weight of the endblocker and the cyclic siloxane, and wherein said compound is selected from the group consisting of cesium silanolates, rubidium silanolates, and mixtures thereof.

7. The method of claim 1 wherein about 0.005 to about 1 weight percent of the compound of element (a)(iii) is used based upon the total weight of the endblocker and cyclic siloxane, and wherein said compound is selected from the group consisting of cesium hydroxide, rubidium hydroxide, and mixtures thereof.

8. The method of claim 1 wherein said volatile organic acid is selected from the group consisting of acetic acid, trimethylacetic acid, trichloroacetic acid, trifluoroacetic acid, benzoic acid, and mixtures thereof.

9. The method of claim 1 wherein said reaction conditions of element (a) comprise a reaction temperature of about 150°

C. to about 160°

C. and a reaction time of about 0.5 to about 2 hours.

10. The method of claim 1 wherein said reaction conditions of element (d) comprise a reaction temperature of about 130°

C. to about 160°

C. and a reaction time of about 4 to about 8 hours and wherein the reaction is conducted under vacuum.

11. A method of making an organopolysiloxane diamine having a number average molecular weight of at least 5000 and being prepared by the steps of

(1) combining under reaction conditions:

(a) amine functional endblocker of the general formula wherein;

##STR12## Y is selected from the group consisting of alkylene radicals of about 1 to about 10 carbon atoms, aralkyl, and aryl radicals;

D is selected from the group consisting of hydrogen, an alkyl radical of 1 to 10 carbon atoms, and phenyl; and

R is each independently selected from the group consisting of a monovalent alkyl radical having from 1 to 12 carbon atoms, a substituted alkyl radical having from 1 to 12 carbon atoms, a phenyl radical, and a substituted phenyl radical;

(b) sufficient cyclic siloxane to react with said amine functional endblocker to form an intermediate organopolysiloxane diamine having a number average molecular weight less than about 2,000 and general formula ##STR13## where;

Y and D are as defined above;

R is at least 50% methyl with the balance of the 100% of all R radicals being selected from the group consisting of a monovalent alkyl radical having from 2 to 12 carbon atoms, a substituted alkyl radical having from 1 to 12 carbon atoms, a vinyl radical, a phenyl radical and a substituted phenyl radical; and

x is a number in the range of about 4 to about 40; and

(c) a catalytic amount of a compound characterized by having a molecular structure represented by the formula;

##STR14## where;

Y and D are as defined above;

R is each independently selected from the group consisting of a monovalent alkyl radical having from 1 to 12 carbon atoms, a substituted alkyl radical having from 2 to 12 carbon atoms, a phenyl radical, and a substituted phenyl radical; and

M⁺ is selected from the cations K⁺, Na⁺ and N(CH₃)₄⁺ ;

(2) continuing the reaction until substantially all of said amine functional endblocker is consumed; and

(3) adding additional cyclic siloxane until said organopolysiloxane diamine having a number average molecular weight of at least 5000 is formed.

12. A method of making an organopolysiloxane diamine having a number average molecular weight of at least about 2000 and having less than or equal to about 0.010 weight % silanol impurities, and being prepared by the steps of

(1) combining under reaction conditions:

(a) amine functional endblocker of the general formula ##STR15## where;

Y is selected from the group consisting of an alkylene radical of 1 to 10 carbon atoms, aralkyl, and aryl radicals;

D is selected from the group consisting of hydrogen, an alkyl radical of 1 to 10 carbon atoms, and phenyl; and

R is each independently selected from the group consisting of a monovalent alkyl radical having from 1 to 12 carbon atoms, a substituted alkyl radical having from 1 to 12 carbon atoms, a phenyl radical, and a substituted phenyl radical;

(b) sufficient cyclic siloxane to react with said amine functional endblocker to form an intermediate organopolysiloxane diamine having a number average molecular weight less than about 2000 and general formula ##STR16## where;

Y and D are as defined above;

R is at least 50% methyl with the balance of the 100% of all R radicals being selected from the group consisting of a monovalent alkyl radical having from 2 to 12 carbon atoms, a substituted alkyl radical having from 1 to 12 carbon atoms, a vinyl radical, a phenyl radical and a substituted phenyl radical; and

x is a number in the range of about 4 to about 40; and

(c) a catalytic amount of a compound characterized by having a molecular structure represented by the formula;

##STR17## where;

Y and D are as defined above;

R is each independently selected from the group consisting of a monovalent alkyl radical having from 1 to 12 carbon atoms, a substituted alkyl radical having from 2 to 12 carbon atoms, a phenyl radical, and a substituted phenyl radical; and

Q⁺ is selected from the cations Cs⁺ and Rb⁺ ;

(2) continuing the reaction until substantially all of said amine functional endblocker is consumed;

(3) adding additional cyclic siloxane in an amount required to obtain the organopolysiloxane diamine of the desired molecular weight;

(4) terminating the reaction by addition of a volatile organic acid to form the organopolysiloxane diamine of at least about 2000 number average molecular weight having less than or equal to about 0.010 weight percent silanol impurities; and

(5) removing any residual cyclic siloxanes and volatile impurities.

13. The method of claim 12 wherein said reaction conditions comprise a reaction temperature of about 150°

to about 160°

C. and a reaction time of about 0.5 to about 2 hours.

14. The method of claim 12 wherein the compound of element (1)(c) is used at less than about 0.025 weight percent based upon the total weight of the organopolysiloxane diamine.

15. The method of claim 12 wherein the compound of element (1)(c) is used at about 0.0025 to about 0.01 weight percent based upon the total weight of the organopolysiloxane diamine.

16. The method of claim 12 wherein the organopolysiloxane diamine has a number average molecular weight greater than about 5000.