Moisture curable polysiloxane release coating compositions

• US 5,286,815 A
• Filed: 02/07/1992
• Issued: 02/15/1994
• Est. Priority Date: 02/07/1992
• Status: Expired due to Term

• Current Assignee: Minnesota Mining and Manufacturing Co (3M Company)
• Original Assignee: Minnesota Mining and Manufacturing Co (3M Company)
• Inventors: Leir, Charles M., Sherman, Audrey A., Sarkar, Manisha
• Primary Examiner(s): Bleutge, John C.
• Assistant Examiner(s): Glass, M. W.
• Application Number:
  US07/832,270
• Time in Patent Office: 739 Days
• Field of Search: 525/477, 528/12, 528/21, 528/34, 528/39, 528/41, 528/33, 524/863
• US Class Current: 525/477
• CPC Class Codes: C08K 5/09 Carboxylic acids; Metal salts thereof; Anhydrides thereof
• CPC Class Codes: C08L 2666/14 Macromolecular compounds according to C08L59/00 - C08L87/00; Derivatives thereof
• CPC Class Codes: C08L 2666/28 Non-macromolecular organic substances
• CPC Class Codes: C08L 83/14 in which at least two but not all the silicon atoms are connected by linkages other than oxygen atoms C08L83/10 takes precedence
• CPC Class Codes: C09D 183/14 in which at least two but not all the silicon atoms are connected by linkages other than oxygen atoms C09D183/10 takes precedence
• CPC Class Codes: C09J 2483/005 in the release coating
• CPC Class Codes: C09J 7/401 characterised by the release coating composition

Abstract

The present invention relates to a release coating composition comprising (a) about 1 to about 100 percent by weight of a particular polysiloxane polymer (I), (b) about 0 to about 99 percent by weight of a silane of a particular formula (II) or hydrolyzates thereof, and (c) about 1 to about 15 percent by weight of a component selected from the group consisting of acids, anhydrides of acids, ammonium and lower alkyl salts of acids and mixtures thereof wherein the acids each have pKas of less than about 3.

Claims

1. A release coating composition comprising:

(a) about 1 to about 100 percent by weight of polymer selected from the group consisting of polymers of the general Formula;

##STR11## and mixtures thereof;

wherein n and m each represent integers, wherein the sum of n plus m is an integer of about 20 to about 5000;

m has a value ranging from about 0 to about 0.1(n+m);

R¹ are monovalent moieties which can be the same or different selected from the group consisting of alkyl, substituted alkyl, aryl, and substituted aryl;

R² are monovalent moieties which can be the same or different selected from the group consisting of alkyl, substituted alkyl, aryl, and substituted aryl;

W are monovalent moieties which can be the same or different selected from the group consisting of alkyl, substituted alkyl, aryl, substituted aryl, and reactive hydrolyzable group ##STR12## wherein at least about 50% of the total number of silicon atoms excluding those in said reactive hydrolyzable group(s) have two methyl groups bonded thereto, and wherein at least one reactive hydrolyzable group ##STR13## appears on each polymer of Formula I and further wherein at least about 25% of the polymers of Formula I in the release coating composition have at least two reactive hydrolyzable groups ##STR14## wherein X are divalent linking groups which can be the same or different selected from the group consisting of alkylene groups comprising about 1 to about 12 carbon atoms;

Q are divalent linking groups which can be the same or different selected from the group consisting of urea, amide, urethane, thiourethane, ether, and thioether groups;

Y are divalent linking groups which can be the same or different selected from the group consisting of alkylene groups comprising about 1 to about 12 carbon atoms;

t is an integer of 0 to 10;

Z are monovalent moieties which can be the same or different selected from the group consisting of --OR and --R wherein R is an alkyl group comprising about 1 to about 3 carbon atoms; and

R³ is a monovalent alkyl group comprising about 1 to about 3 carbon atoms;

(b) about 0 to about 99 percent by weight of a component selected from the group consisting of compounds and polymers of the general Formula;

space="preserve" listing-type="equation">(R.sup.3 O).sub.3 --Si--A (ii)

hydrolysates thereof, and mixtures thereof, wherein

R³ is as previously defined;

A is a monovalent moiety selected from the group consisting of --OR³, monovalent alkyl groups comprising about 1 to about 20 carbon atoms, and --X--(Q)_p --[D--Q]_t --(Y)_b --Si(OR³)₃, wherein

X, Q, t, Y and R³ are as previously defined;

D is a divalent group which can be the same or different selected from the group consisting of alkylene groups comprising from about 2 to about 30 carbon atoms;

aralkylene groups comprising from about 6 to about 30 carbon atoms;

arylene groups comprising from about 6 to about 30 carbon atoms; and

divalent polymeric segments having a number average molecular weight of about 500 to about 10,000 selected from the group consisting of polyether, polyolefin, polyester, polydiene, and mixtures thereof;

p is an integer of from 0 to 1;

b is an integer of from 0 to 1;

wherein when t is an integer of 1 to 10, b must equal 1 and p must equal 1;

wherein when t=0 and b=0, p must also equal 0;

wherein the weight percentages of (a) and (b) are based upon the total weight of (a) plus (b); and

(c) about 1 to about 15 percent by weight based upon the total weight of (a) plus (b) of a component selected from the group consisting of acids having pKas of less than about 3, anhydrides of acids having pKas of less than about 3, ammonium salts of acids having pKas of less than about 3, lower alkyl ammonium salts of acids having pKas of less than about 3, and mixtures thereof.

2. The release coating composition of claim 1 wherein R¹ and R² each comprise methyl groups, X and Y each comprise --CH₂ CH₂ CH₂ --, t equals 1, and Q is independently selected from the group consisting of urea and thioether groups.

3. The release coating composition of claim 1 wherein the sum of n plus m is an integer of about 70 to about 1000.

4. The release coating composition of claim 1 wherein the sum of n plus m is an integer of about 70 to about 500.

5. The release coating composition of claim 1 wherein the release coating composition comprises about 3 to about 10 percent by weight of component (c) based on the total weight of (a) plus (b).

6. The release coating composition of claim 1 wherein each Z moiety comprises --OCH₃ and each R³ group comprises --CH₃.

7. The release coating composition of claim 1 wherein the release coating composition comprises from about 5 to about 30 percent by weight of polymer of Formula I, based on the total weight of (a) plus (b).

8. The release coating composition of claim 1 wherein the release coating composition comprises from about 50 to about 90 percent by weight of polymer of Formula I, based on the total weight of (a) plus (b).

9. The release coating composition of claim 1 wherein the component of Formula II is selected from the group consisting of alkoxysilyl terminated polypropylene oxide, alkoxysilyl terminated polyethylene oxide, alkoxysilyl terminated polycaprolactone, alkoxy silyl terminated polytetramethylene oxide, alkoxysilyl terminated alkanes, alkoxysilane terminated ethers, alkoxy terminated thioethers, tetraalkoxy silyl compounds, and mixtures thereof.

10. The release coating composition of claim 1 wherein component (b) comprises about 1 to about 15 percent by weight of colloidal silica based upon the total weight of (a) plus (b).

11. The release coating composition of claim 1 wherein the component of element (c) is selected from the group consisting of trichloroacetic acid, cyanoacetic acid, malonic acid, nitroacetic acid, dichloroacetic acid, difluoroacetic acid, trichloroacetic anhydride, dichloroacetic anhydride, difluoroacetic anhydride, triethylammonium trichloroacetate, trimethylammonium trichloroacetate, and mixtures thereof.

14. A release coating formed from curing the composition of claim 1.

17. A substrate coated with the release coating of claim 14.

12. A release coating composition comprising:

(a) about 1 to about 100 percent by weight of polymer selected from the group consisting of polymers of the general Formula;

##STR15## and mixtures thereof;

wherein n and m each represent integers, wherein the sum of n plus m is an integer of about 70 to about 1000;

m has a value ranging from about 0 to about 0.1(n+m)

R¹ are monovalent moieties which can be the same or different selected from the group consisting of alkyl, substituted alkyl, aryl, and substituted aryl;

R² are monovalent moieties which can be the same or different selected from the group consisting of alkyl, substituted alkyl, aryl, and substituted aryl;

W are monovalent moieties which can be the same or different selected from the group consisting of alkyl, substituted alkyl, aryl, substituted aryl, and reactive hydrolyzable group ##STR16## wherein at least about 50% of the total number of silicon atoms excluding those in said reactive hydrolyzable group(s) have two methyl groups bonded thereto, and wherein at least one reactive hydrolyzable group ##STR17## appears on each polymer of Formula I and further wherein at least about 25% of the polymers of Formula I in the release coating composition have at least two reactive hydrolyzable groups ##STR18## wherein X are divalent linking groups which can be the same or different selected from the group consisting of alkylene groups comprising about 1 to about 12 carbon atoms;

Q are divalent linking groups which can be the same or different selected from the group consisting of urea, amide, urethane, thiourethane, ether, and thioether groups;

Y are divalent linking groups which can be the same or different selected from the group consisting of alkylene groups comprising about 1 to about 12 carbon atoms;

t is an integer of 0 to 10;

Z are monovalent moieties which can be the same or different selected from the group consisting of --OR and --R wherein R is an alkyl group comprising about 1 to about 3 carbon atoms; and

R³ is a monovalent alkyl group comprising about 1 to about 3 carbon atoms;

(b) about 0 to about 99 percent by weight of a component selected from the group consisting of compounds and polymers of the general Formula;

space="preserve" listing-type="equation">(R.sup.3 O).sub.3 --Si--A (II)

hydrolysates thereof, and mixtures thereof, wherein

R³ is as previously defined;

A is a monovalent moiety selected from the group consisting of --OR³, monovalent alkyl groups comprising about 1 to about 20 carbon atoms, and --X--(Q)_p --[D--Q]_t --(Y)_b --Si(OR³)₃ wherein

X, Q, t, Y and R³ are as previously defined;

D is a divalent group which can be the same or different selected from the group consisting of alkylene groups comprising from about 2 to about 30 carbon atoms;

aralkylene groups comprising from about 6 to about 30 carbon atoms;

arylene groups comprising from about 6 to about 30 carbon atoms; and

divalent polymeric segments having a number average molecular weight of about 500 to about 10,000 selected from the group consisting of polyether, polyolefin, polyester, polydiene, and mixtures thereof;

p is an integer of from 0 to 1;

b is an integer of from 0 to 1;

wherein when t is an integer of 1 to 10, b must equal 1 and p must equal 1;

wherein when t=0 and b=0, p must also equal 0;

wherein the weight percentages of (a) and (b) are based upon the total weight of (a) plus (b); and

(c) about 3 to about 10 percent by weight based upon the total weight of (a) plus (b) of a component selected from the group consisting of acids having pKas of less than about 3, anhydrides of acids having pKas of less than about 3, ammonium salts of acids having pKas of less than about 3, lower alkyl ammonium salts of acids having pKas of less than about 3, and mixtures thereof.

15. A release coating formed from curing the release coating composition of claim 12.

18. A substrate coated with the release coating of claim 15.

13. A release coating composition comprising:

(a) about 1 to about 99 percent by weight of polymer selected from the group consisting of polymers of the general Formula;

##STR19## and mixtures thereof;

wherein n and m each represent integers, wherein the sum of n plus m is an integer of about 70 to about 500;

m has a value ranging from about 0 to about 0.1(n+m);

R¹ are monovalent moieties which can be the same or different selected from the group consisting of alkyl, substituted alkyl, aryl, and substituted aryl;

R² are monovalent moieties which can be the same or different selected from the group consisting of alkyl, substituted alkyl, aryl, and substituted aryl;

W are monovalent moieties which can be the same or different selected from the group consisting of alkyl, substituted alkyl, aryl, substituted aryl, and reactive hydrolyzable group ##STR20## wherein at least about 50% of the total number of silicon atoms excluding those in said reactive hydrolyzable group(s) have two methyl groups bonded thereto, and wherein at least one reactive hydrolyzable group ##STR21## appears on each polymer of Formula I and further wherein at least about 25% of the polymers of Formula I in the release coating composition have at least two reactive hydrolyzable groups ##STR22## wherein X are divalent linking groups which can be the same or different selected from the group consisting of alkylene groups comprising about 1 to about 12 carbon atoms;

Q are divalent linking groups which can be the same or different selected from the group consisting of urea, amide, urethane, thiourethane, ether, and thioether groups;

Y are divalent linking groups which can be the same or different selected from the group consisting of alkylene groups comprising about 1 to about 12 carbon atoms;

t is an integer of 0 to 10;

Z are monovalent moieties which can be the same or different selected from the group consisting of --OR and --R wherein R is an alkyl group comprising about 1 to about 3 carbon atoms; and

R³ is a monovalent alkyl group comprising about 1 to about 3 carbon atoms;

(b) about 1 to about 99 percent by weight of a component selected from the group consisting of compounds and polymers of the general Formula;

space="preserve" listing-type="equation">(R.sup.3 O).sub.3 --Si--A (II)

hydrolysates thereof, and mixtures thereof, wherein

R³ is as previously defined;

A is a monovalent moiety selected from the group consisting of --OR³, monovalent alkyl groups comprising about 1 to about 20 carbon atoms, and --X--(Q)_p --[D--Q]_t --(Y)_b --Si(OR³)₃, wherein

X, Q, t, Y and R³ are as previously defined;

D is a divalent group which can be the same or different selected from the group consisting of alkylene groups comprising from about 2 to about 30 carbon atoms;

aralkylene groups comprising from about 6 to about 30 carbon atoms;

arylene groups comprising from about 6 to about 30 carbon atoms;

divalent polymeric segments having a number average molecular weight of about 500 to about 10,000 selected from the group consisting of polyether, polyolefin, polyester, polydiene, and mixtures thereof;

p is an integer of from 0 to 1;

b is an integer of from 0 to 1;

wherein when t is an integer of 1 to 10, b must equal 1 and p must equal 1;

wherein when t=0 and b=0, p must also equal 0;

wherein the weight percentages of (a) and (b) are based upon the total weight of (a) plus (b); and

(c) about 3 to about 10 percent by weight based upon the total weight of (a) plus (b) of a component selected from the group consisting of acids having pKas of about 0.1 to about 1.5, anhydrides of acids having pKas of about 0.1 to about 1.5, ammonium salts of acids having pKas of about 0.1 to about 1.5, lower alkyl ammonium salts of acids having pKas of about 0.1 to about 1.5, and mixtures thereof.

16. A release coating formed from curing the release coating composition of claim 13.

19. A substrate coated with the release coating of claim 16.

20. A method of forming a release coating coated substrate comprising the steps of:

(a) applying to a substrate a layer of a release coating composition, wherein said release coating composition comprises;

(i) about 1 to about 100 percent by weight of polymer selected from the group consisting of polymers of the general Formula;

##STR23## and mixtures thereof;

wherein n and m each represent integers, wherein the sum of n plus m is an integer of about 20 to about 5000;

m has a value ranging from about 0 to about 0.1(n+m);

R¹ are monovalent moieties which can be the same or different selected from the group consisting of alkyl, substituted alkyl, aryl, and substituted aryl;

R² are monovalent moieties which can be the same or different selected from the group consisting of alkyl, substituted alkyl, aryl, and substituted aryl;

W are monovalent moieties which can be the same or different selected from the group consisting of alkyl, substituted alkyl, aryl, substituted aryl, and reactive hydrolyzable group ##STR24## wherein at least about 50% of the total number of silicon atoms excluding those in said reactive hydrolyzable group(s) have two methyl groups bonded thereto, and wherein at least one reactive hydrolyzable group ##STR25## appears on each polymer of Formula I and further wherein at least about 25% of the polymers of Formula I in the release coating composition have at least two reactive hydrolyzable groups ##STR26## wherein X are divalent linking groups which can be the same or different selected from the group consisting of alkylene groups comprising about 1 to about 12 carbon atoms;

Q are divalent linking groups which can be the same or different selected from the group consisting of urea, amide, urethane, thiourethane, ether, and thioether groups;

Y are divalent linking groups which can be the same or different selected from the group consisting of alkylene groups comprising about 1 to about 12 carbon atoms;

t is an integer of 0 to 10;

Z are monovalent moieties which can be the same or different selected from the group consisting of --OR and --R wherein R is an alkyl group comprising about 1 to about 3 carbon atoms; and

R³ is a monovalent alkyl group comprising about 1 to about 3 carbon atoms;

(ii) about 0 to about 99 percent by weight of a component selected from the group consisting of compounds and polymers of the general Formula;

space="preserve" listing-type="equation">(R.sup.3 O).sub.3 --Si--A (II)

hydrolysates thereof, and mixtures thereof, wherein

R³ is as previously defined;

A is a monovalent moiety selected from the group consisting of --OR³, monovalent alkyl groups comprising about 1 to about 20 carbon atoms, and --X--(Q)_p --[D--Q]_t --(Y)_b --Si(OR³)₃ wherein

X, Q, t, Y and R³ are as previously defined;

D is a divalent group which can be the same or different selected from the group consisting of alkylene groups comprising from about 2 to about 30 carbon atoms;

aralkylene groups comprising from about 6 to about 30 carbon atoms;

arylene groups comprising from about 6 to about 30 carbon atoms; and

divalent polymeric segments having a number average molecular weight of about 500 to about 10,000 selected from the group consisting of polyether, polyolefin, polyester, polydiene, and mixtures thereof;

p is an integer of from 0 to 1;

b is an integer of from 0 to 1;

wherein when t is an integer of 1 to 10, b must equal 1 and p must equal 1;

wherein when t=0 and b=0, p must also equal 0;

wherein the weight percentages of (i) and (ii) are based upon the total weight of (i) plus (ii); and

(iii) about 1 to about 15 percent by weight based upon the total weight of (i) plus (ii) of a component selected from the group consisting of ammonium salts of acids having pKas of less than about 3, lower alkyl ammonium salts of acids having pKas of less than about 3, and mixtures thereof;

(b) heating said release coating composition sufficiently to dissociate the component selected from the group consisting of ammonium salts of acids having pKas of less than about 3, lower alkyl ammonium salts of acids having pKas of less than about 3, and mixtures thereof, in order to evaporate ammonia, amine(s), or both, and yield acid(s) having pKas of less than 3; and

,

(c) exposing said release coating composition to atmospheric moisture sufficient to cure said reactive hydrolyzable groups to form Si--O--Si crosslinks.

21. A method of forming a release coating coated substrate comprising the steps of:

(a) applying to a substrate a layer of a release coating composition, wherein said release coating composition comprises;

(i) about 1 to about 100 percent by weight of polymer selected from the group consisting of polymers of the general Formula;

##STR27## and mixtures thereof;

wherein n and m each represent integers, wherein the sum of n plus m is an integer of about 20 to about 5000;

m has a value ranging from about 0 to about 0.1(n+m);

R¹ are monovalent moieties which can be the same or different selected from the group consisting of alkyl, substituted alkyl, aryl, and substituted aryl;

R² are monovalent moieties which can be the same or different selected from the group consisting of alkyl, substituted alkyl, aryl, and substituted aryl;

W are monovalent moieties which can be the same or different selected from the group consisting of alkyl, substituted alkyl, aryl, substituted aryl, and reactive hydrolyzable group ##STR28## wherein at least about 50% of the total number of silicon atoms excluding those in said reactive hydrolyzable group(s) have two methyl groups bonded thereto, and wherein at least one reactive hydrolyzable group ##STR29## appears on each polymer of Formula I and further wherein at least about 25% of the polymers of Formula I in the release coating composition have at least two reactive hydrolyzable groups ##STR30## wherein X are divalent linking groups which can be the same or different selected from the group consisting of alkylene groups comprising about 1 to about 12 carbon atoms;

Q are divalent linking groups which can be the same or different selected from the group consisting of urea, amide, urethane, thiourethane, ether, and thioether groups;

Y are divalent linking groups which can be the same or different selected from the group consisting of alkylene groups comprising about 1 to about 12 carbon atoms;

t is an integer of 0 to 10;

Z are monovalent moieties which can be the same or different selected from the group consisting of --OR and --R wherein R is an alkyl group comprising about 1 to about 3 carbon atoms; and

R³ is a monovalent alkyl group comprising about 1 to about 3 carbon atoms;

(ii) about 0 to about 99 percent by weight of a component selected from the group consisting of compounds and polymers of the general Formula;

space="preserve" listing-type="equation">(R.sup.3 O).sub.3 --Si--A (II)

hydrolysates thereof, and mixtures thereof, wherein

R³ is as previously defined;

A is a monovalent moiety selected from the group consisting of --OR³, monovalent alkyl groups comprising about 1 to about 20 carbon atoms, and --X--(Q)_p --[D--Q]_t --(Y)_b --Si(OR³)₃ wherein

X, Q, t, Y and R³ are as previously defined;

D is a divalent group which can be the same or different selected from the group consisting of alkylene groups comprising from about 2 to about 30 carbon atoms;

aralkylene groups comprising from about 6 to about 30 carbon atoms;

arylene groups comprising from about 6 to about 30 carbon atoms; and

divalent polymeric segments having a number average molecular weight of about 500 to about 10,000 selected from the group consisting of polyether, polyolefin, polyester, polydiene, and mixtures thereof;

p is an integer of from 0 to 1;

b is an integer of from 0 to 1;

wherein when t is an integer of 1 to 10, b must equal 1 and p must equal 1;

wherein when t=0 and b=0, p must also equal 0;

wherein the weight percentages of (i) and (ii) are based upon the total weight of (i) plus (ii); and

(iii) about 1 to about 15 percent by weight based upon the total weight of (i) plus (ii) of a component selected from the group consisting of acids having pKas of less than about 3, anhydrides of acids having pKas of less than about 3, and mixtures thereof; and

(b) exposing said relese coating composition to atmospheric moisture sufficient to cure said reactive hydrolyzable groups to form Si--O--Si crosslinks.