Method for vulcanizing a green tire using an organopolysiloxane-based mold release agent lubricant composition

Patent metadata

Field	Value
Publication number	US-12447704-B2
Application number	US-202017787574-A
Country	US
Kind code	B2
Filing date	Dec 18, 2020
Priority date	Dec 20, 2019
Publication date	Oct 21, 2025
Grant date	Oct 21, 2025

Abstract

A method is described for vulcanizing a green tire using an organopolysiloxane-based mold release agent lubricant composition. Also described, is an organopolysiloxane-based mold release agent lubricant composition.

First claim

The invention claimed is:

1. A colored lubricant mold-release composition (I) comprising:
a. at least one organopolysiloxane (A); selected from the group consisting of:
non-reactive organopolysiloxanes (E) which, per molecule, comprise monovalent organic substituents, that are identical or different, bonded to the silicon atoms, and that are selected from the group consisting of C 1 -C 40 alkyl, C 3 -C 8 cycloalkyl, C 6 -C 10 aryl and C 7 -C 50 alkylaryl radicals;
reactive organopolysiloxanes (F) including at least two ≡SiOH silanol groups per molecule;
and mixtures thereof,

b. at least one surfactant (B),
c. at least one non-fluorescent pigment (C) selected from the group consisting of, according to the color Index classification: monoazo, disazo, amino ketone, indigoid, phthalocyanine, oxazine, and mixtures thereof; and
d. water (D);
wherein amounts of the surfactant(s) and the water are sufficient to obtain an oil-in-water emulsion such that the colored lubricant mold-release composition (I) is in the form of an oil-in-water emulsion.

2. The composition (I) as claimed in claim 1 , wherein, the composition exhibits a loss of color (X) of between 85% and 100%, after the composition has been deposited on an expandable vulcanization bladder and/or on a green tire and heat-treated at 170° C. for 20 minutes, wherein the loss of color (X) is determined by spectrocolorimetry in the following manner:

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3. The composition (I) as claimed in claim 1 , wherein the composition comprises between 0.01% and 3% by weight of non-fluorescent pigment (C) relative to the total weight of composition (I).

4. The composition (I) as claimed in claim 1 , wherein the composition further comprises (i) at least one crosslinking agent (G) comprising, per molecule, at least three ≡SiH units, and/or (ii) a catalyst (H).

5. The composition (I) as claimed in claim 1 , wherein the composition further comprises an air scavenger (J).

6. The composition (I) as claimed in claim 1 , wherein the composition comprises
from 0.1 to 60 parts by weight of at least one polyorganosiloxane (A),
from 0.1 to 10 parts by weight of at least one surfactant (B),
from 0.01 to 3 parts by weight of at least one non-fluorescent pigment (C),
from 20 to 90 parts by weight of water (D),
from 0 to 20 parts by weight of at least one crosslinking agent (G),
from 0 to 5 parts by weight of at least one catalyst (H),
from 0 to 20 parts by weight of an air scavenger (J),
from 0 to 5 parts by weight of at least one additive (K),
per 100 parts by weight of the sum of the constituents (A), (B), (C), (D), (G), (H), (J), and (K).

7. The composition (I) as claimed in claim 1 , wherein the non-fluorescent pigment (C) is in the form of an aqueous dispersion.

8. The composition (I) as claimed in claim 3 , wherein the non-fluorescent pigment (C) is present in an amount of from about 0.1% to about 2.5% by weight.

9. The composition (I) as claimed in claim 6 , wherein the at least one polyorganopolysiloxane (A) is present in an amount of from about 0.1 parts by weight to about 30 parts by weight.

10. The composition (I) as claimed in claim 6 , wherein the water (D) is present in an amount of from about 30 parts by weight to about 80 parts by weight.

11. The composition (I) as claimed in claim 6 , wherein the air scavenger (J) is present in an amount of from about 0.1 parts by weight to about 15 parts by weight.

12. A process of lubricating (P1) an expandable rubber bladder that is useful in the vulcanization of a green tire in a metal press, the process comprising bringing the outer surface of the bladder into contact with an inner face of the green tire that is coated with the colored lubricant mold-release composition (I) as claimed in claim 1 , and wherein the process results in the expandable rubber bladder being lubricated on its outer surface.

13. A process of lubricating (P2) an expandable rubber bladder that is useful during the vulcanization of a green tire in a metal press, the process comprising in a first step outside the press, of coating the inner surface of the green tire with the colored lubricant mold-release composition (I) as claimed in claim 1 ; the step thus producing a green tire whose inner surface is coated with the composition (I); and in a subsequent step in the metal press, the green tire whose inner surface is coated with composition (I) is placed in contact with an expandable rubber bladder; the process thus producing by transfer an expandable rubber bladder that is lubricated on its outer face.

14. An expandable rubber bladder or green tire, coated with a colored lubricant mold-release composition (I) as claimed in claim 1 .

15. A process of vulcanizing a green tire in a metal press using an expandable rubber bladder, the process comprising the following steps:
1. coating an inside surface of the green tire and/or an outside surface of the expandable rubber bladder with a colored lubricant mold-release composition (I), in the form of an oil-in-water emulsion, to form a colored coating that is visible to the naked eye on the green tire and/or on the bladder, the lubricant composition (I) comprising:
a. at least one organopolysiloxane (A) selected from the group consisting of:
non-reactive organopolysiloxanes (E) which, per molecule, comprise monovalent organic substituents, that are identical or different, bonded to the silicon atoms,

Assignees

• Elkem Silicones France Sas

Inventors

• Feder Michel
• Breunig Stefan

Classifications

• C08L83/04

  Polysiloxanes · CPC title

• B29D2030/0659

  Details or accessories for the flexible cores not otherwise provided for · CPC title

• B29D30/0662

  Accessories, details or auxiliary operations · CPC title

• B29C33/64 Primary

  Silicone · CPC title

• B29C33/58

  Applying the releasing agents · CPC title