1. An organopolysiloxane composition for magnesium alloy bonding, having improved chemical resistance, said composition comprising
(A) 100 parts by weight of an organopolysiloxane having the general formula (1):
wherein R is each independently a substituted or unsubstituted monovalent hydrocarbon radical of 1 to 10 carbon atoms, X is an oxygen atom or an alkylene radical of 2 to 5 carbon atoms, Me is methyl, n is an integer of at least 10, and m is each independently 0 or 1, or an organopolysiloxane having the general formula (2):
wherein R, Me, X and m are as defined above, p is an integer of at least 10, q is an integer of 1 to 5, and R1 is a branching chain containing hydrolyzable radicals of the formula (3):
wherein R, Me, X and m are as defined above, or a mixture thereof,
(B) 1 to 50 parts by weight of a non-reactive silicone oil,
(C) 20 to 100 parts by weight of zinc oxide which is surface treated with a silane or siloxane treating agent,
(D) 20 to 100 parts by weight of heavy calcium carbonate which is surface treated with a paraffin treating agent,
(E) 0.1 to 30 parts by weight of an organosilicon compound having at least three hydrolyzable radicals each bonded to a silicon atom in the molecule or a partial hydrolyzate thereof,
(F) 0.1 to 10 parts by weight of a silane coupling agent having at least one epoxy radical in the molecule, and
(G) an effective amount of a titanium chelate catalyst,
wherein components (C) and (D) are present in a weight ratio CD between 0.5 and 1.5.
2. The organopolysiloxane composition of claim 1, for use as automobile sealant.
3. A method for bonding a silicone rubber to magnesium alloy comprising the steps of supplying an organopolysiloxane composition for magnesium alloy bonding, having improved chemical resistance to the magnesium alloy, said composition comprising
(A) 100 parts by weight of an organopolysiloxane having the general formula (1):
wherein R is each independently a substituted or unsubstituted monovalent hydrocarbon radical of 1 to 10 carbon atoms, X is an oxygen atom or an alkylene radical of 2 to 5 carbon atoms, Me is methyl, n is an integer of at least 10, and m is each independently 0 or 1, or an organopolysiloxane having the general formula (2):
wherein R, Me, X and m are as defined above, p is an integer of at least 10, q is an integer of 1 to 5, and R1 is a branching chain containing hydrolyzable radicals of the formula (3):
wherein R, Me, X and m are as defined above, or a mixture thereof,
(B) 5 to 50 parts by weight of a non-reactive silicone oil,
(C) 20 to 100 parts by weight of zinc oxide which is surface treated with a silane or siloxane treating agent,
(D) 20 to 100 parts by weight of heavy calcium carbonate which is surface treated with a paraffin treating agent,
(E) 0.1 to 30 parts by weight of an organosilicon compound having at least three hydrolyzable radicals each bonded to a silicon atom in the molecule or a partial hydrolyzate thereof,
(F) 0.1 to 10 parts by weight of a silane coupling agent having at least one epoxy radical in the molecule, and
(G) an effective amount of a titanium chelate catalyst, wherein components (C) and (D) are present in a weight ratio CD between 0.5 and 1.5, and curing the composition, thereby the cured composition and the magnesium alloy are bonded.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A process for preparing a poly(1,4-(2,5-dihydroxy)phenylene-2,6-pyrido2,3-d:5,6-d\u2032bisimidazole polymer comprising:
contacting a molar excess of a 2,3,5,6-tetraamino pyridine free base in water with a 2,5-dihydroxy terephthalic acid salt to form an aqueous mixture,
adjusting the pH of the aqueous mixture to within the range of from about 3 to about 5 to precipitate a monomer complex composed of 2,3,5,6-tetraamino pyridine and 2,5-dihydroxy terephthalic acid monomers,
contacting, in polyphosphoric acid, the monomer complex with about 0.05 to about 0.9 weight percent metal powder based on the total weight of the monomers, and
polymerizing the monomer complex in polyphosphoric acid to form the polymer.
2. The process of claim 1 wherein the molar ratio of the 2,3,5,6-tetraamino pyridine to the 2,5-dihydroxy terephthalic acid monomers is in excess of about 1.05 to 1.
3. The process of claim 1 wherein the pH is adjusted by adding orthophosphoric acid to the aqueous mixture.
4. The process of claim 1 wherein the polyphosphoric acid has an equivalent P2O5 content of at least about 81 percent after polymerization.
5. The process of claim 1 wherein the metal powder comprises iron powder, tin powder, vanadium powder, chromium powder, or any combination thereof.
6. The process of claim 5, wherein the metal powder comprises iron.
7. The process of claim 1, wherein the 2,5-dihydroxy terephthalic acid salt is an alkaline salt or an ammonium salt of 2,5-dihydroxy terephthalic acid.
8. The process of claim 7, wherein the alkaline salt is 2,5-dihydroxy terephthalic acid dipotassium salt.
9. The process of claim 1 including the additional step of forming a fiber from the polymer.
10. The process of claim 1, wherein the poly(1,4-(2,5-dihydroxy)phenylene-2,6-pyrido2,3-d:5,6-d\u2032bisimidazole) is characterized as providing a polymer solution having an inherent viscosity of at least about 22 dlg at 30\xb0 C. at a polymer concentration of 0.05 gdl in methane sulfonic acid.
11. A process for preparing a poly(1,4-(2,5-dihydroxy)phenylene-2,6-pyrido2,3-d:5,6-d\u2032bisimidazole) polymer comprising:
contacting 2,3,5,6-tetraamino pyridine free base in water with 2,5-dihydroxy terephthalic acid dipotassium salt to form an aqueous mixture,
adjusting the pH of the aqueous mixture to within the range of from about 3 to about 5 to precipitate a monomer complex composed of 2,3,5,6-tetraamino pyridine and 2,5-dihydroxy terephthalic acid monomers,
contacting, in polyphosphoric acid, the monomer complex with about 0.05 to about 0.9 weight percent metal powder based on the total weight of the monomers, and
polymerizing the monomer complex in polyphosphoric acid to form the polymer.
12. The process of claim 11 wherein the molar ratio of the 2,3,5,6-tetraamino pyridine to the 2,5-dihydroxy terephthalic acid monomers is in excess of about 1 to 1.
13. The process of claim 12 wherein the molar ratio of the 2,3,5,6-tetraamino pyridine to the 2,5-dihydroxy terephthalic acid monomers is in excess of about 1.05 to 1.
14. The process of claim 11 wherein the pH is adjusted by adding orthophosphoric acid to the aqueous mixture.
15. The process of claim 11 wherein the polyphosphoric acid has an equivalent P2O5 content of at least about 81 percent after polymerization.
16. The process of claim 15 wherein the polyphosphoric acid has an equivalent P2O5 content of at least about 82 percent after polymerization.
17. The process of claim 11 wherein the metal powder comprises iron powder, tin powder, vanadium powder, chromium powder, or any combination thereof.
18. The process of claim 17 wherein the metal powder comprises iron.
19. The process of claim 11 including the additional step of forming a fiber from the polymer.
20. The process of claim 11, wherein the poly(1,4-(2,5-dihydroxy)phenylene-2,6-pyrido2,3-d:5,6-d\u2032bisimidazole) is characterized as providing a polymer solution having an inherent viscosity of at least about 22 dlg at 30\xb0 C. at a polymer concentration of 0.05 gdl in methane sulfonic acid.