WO2024091798A1 - Silicone coating composition with mica - Google Patents
Silicone coating composition with mica Download PDFInfo
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- WO2024091798A1 WO2024091798A1 PCT/US2023/076643 US2023076643W WO2024091798A1 WO 2024091798 A1 WO2024091798 A1 WO 2024091798A1 US 2023076643 W US2023076643 W US 2023076643W WO 2024091798 A1 WO2024091798 A1 WO 2024091798A1
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- WIPO (PCT)
- Prior art keywords
- mica
- composition
- resin
- dimethylsiloxane
- terminated poly
- Prior art date
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- 239000000203 mixture Substances 0.000 title claims abstract description 37
- 229910052618 mica group Inorganic materials 0.000 title claims abstract description 32
- 239000010445 mica Substances 0.000 title claims abstract description 30
- 239000004447 silicone coating Substances 0.000 title description 3
- 239000011347 resin Substances 0.000 claims abstract description 27
- 229920005989 resin Polymers 0.000 claims abstract description 27
- 229920000435 poly(dimethylsiloxane) Polymers 0.000 claims abstract description 22
- 238000000576 coating method Methods 0.000 claims abstract description 19
- -1 poly(dimethylsiloxane) Polymers 0.000 claims abstract description 18
- 239000011248 coating agent Substances 0.000 claims abstract description 10
- 239000000758 substrate Substances 0.000 claims abstract description 9
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical group CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 claims description 9
- 239000003054 catalyst Substances 0.000 claims description 9
- BFXIKLCIZHOAAZ-UHFFFAOYSA-N methyltrimethoxysilane Chemical group CO[Si](C)(OC)OC BFXIKLCIZHOAAZ-UHFFFAOYSA-N 0.000 claims description 6
- 238000013008 moisture curing Methods 0.000 claims description 6
- 239000003431 cross linking reagent Substances 0.000 claims description 5
- QYFRTHZXAGSYGT-UHFFFAOYSA-L hexaaluminum dipotassium dioxosilane oxygen(2-) difluoride hydrate Chemical compound O.[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[F-].[F-].[Al+3].[Al+3].[Al+3].[Al+3].[Al+3].[Al+3].[K+].[K+].O=[Si]=O.O=[Si]=O.O=[Si]=O.O=[Si]=O.O=[Si]=O.O=[Si]=O QYFRTHZXAGSYGT-UHFFFAOYSA-L 0.000 claims description 5
- UQEAIHBTYFGYIE-UHFFFAOYSA-N hexamethyldisiloxane Chemical compound C[Si](C)(C)O[Si](C)(C)C UQEAIHBTYFGYIE-UHFFFAOYSA-N 0.000 claims description 5
- 239000002904 solvent Substances 0.000 claims description 5
- UHOPWFKONJYLCF-UHFFFAOYSA-N 2-(2-sulfanylethyl)isoindole-1,3-dione Chemical compound C1=CC=C2C(=O)N(CCS)C(=O)C2=C1 UHOPWFKONJYLCF-UHFFFAOYSA-N 0.000 claims description 3
- DKPFZGUDAPQIHT-UHFFFAOYSA-N Butyl acetate Natural products CCCCOC(C)=O DKPFZGUDAPQIHT-UHFFFAOYSA-N 0.000 claims description 3
- 125000002777 acetyl group Chemical group [H]C([H])([H])C(*)=O 0.000 claims description 3
- FUZZWVXGSFPDMH-UHFFFAOYSA-N hexanoic acid Chemical compound CCCCCC(O)=O FUZZWVXGSFPDMH-UHFFFAOYSA-N 0.000 claims description 3
- YKYONYBAUNKHLG-UHFFFAOYSA-N n-Propyl acetate Natural products CCCOC(C)=O YKYONYBAUNKHLG-UHFFFAOYSA-N 0.000 claims description 3
- 229910052628 phlogopite Inorganic materials 0.000 claims description 3
- 229940090181 propyl acetate Drugs 0.000 claims description 3
- NQPDZGIKBAWPEJ-UHFFFAOYSA-N valeric acid Chemical compound CCCCC(O)=O NQPDZGIKBAWPEJ-UHFFFAOYSA-N 0.000 claims description 3
- 239000000919 ceramic Substances 0.000 claims description 2
- YGANSGVIUGARFR-UHFFFAOYSA-N dipotassium dioxosilane oxo(oxoalumanyloxy)alumane oxygen(2-) Chemical compound [O--].[K+].[K+].O=[Si]=O.O=[Al]O[Al]=O YGANSGVIUGARFR-UHFFFAOYSA-N 0.000 claims description 2
- 239000011521 glass Substances 0.000 claims description 2
- 229910052751 metal Inorganic materials 0.000 claims description 2
- 239000002184 metal Substances 0.000 claims description 2
- 229910044991 metal oxide Inorganic materials 0.000 claims description 2
- 150000004706 metal oxides Chemical class 0.000 claims description 2
- 229910052627 muscovite Inorganic materials 0.000 claims description 2
- 238000006116 polymerization reaction Methods 0.000 claims 1
- 238000005336 cracking Methods 0.000 description 8
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 239000004205 dimethyl polysiloxane Substances 0.000 description 5
- 238000004987 plasma desorption mass spectroscopy Methods 0.000 description 5
- 238000009472 formulation Methods 0.000 description 4
- 239000011253 protective coating Substances 0.000 description 4
- VXUYXOFXAQZZMF-UHFFFAOYSA-N titanium(IV) isopropoxide Chemical compound CC(C)O[Ti](OC(C)C)(OC(C)C)OC(C)C VXUYXOFXAQZZMF-UHFFFAOYSA-N 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 235000013870 dimethyl polysiloxane Nutrition 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- CXQXSVUQTKDNFP-UHFFFAOYSA-N octamethyltrisiloxane Chemical compound C[Si](C)(C)O[Si](C)(C)O[Si](C)(C)C CXQXSVUQTKDNFP-UHFFFAOYSA-N 0.000 description 3
- 230000035939 shock Effects 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 230000032798 delamination Effects 0.000 description 2
- 239000000945 filler Substances 0.000 description 2
- 230000007774 longterm Effects 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 229920001296 polysiloxane Polymers 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 238000003878 thermal aging Methods 0.000 description 2
- 241001595840 Margarites Species 0.000 description 1
- 229910020485 SiO4/2 Inorganic materials 0.000 description 1
- 229910020175 SiOH Inorganic materials 0.000 description 1
- YKTSYUJCYHOUJP-UHFFFAOYSA-N [O--].[Al+3].[Al+3].[O-][Si]([O-])([O-])[O-] Chemical compound [O--].[Al+3].[Al+3].[O-][Si]([O-])([O-])[O-] YKTSYUJCYHOUJP-UHFFFAOYSA-N 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000000010 aprotic solvent Substances 0.000 description 1
- 229910052626 biotite Inorganic materials 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 229910052918 calcium silicate Inorganic materials 0.000 description 1
- 239000000378 calcium silicate Substances 0.000 description 1
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 229910052681 coesite Inorganic materials 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 238000001723 curing Methods 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 229910052631 glauconite Inorganic materials 0.000 description 1
- 239000011256 inorganic filler Substances 0.000 description 1
- 229910003475 inorganic filler Inorganic materials 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 1
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 description 1
- 229910052629 lepidolite Inorganic materials 0.000 description 1
- 229910052630 margarite Inorganic materials 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- XZZXKVYTWCYOQX-UHFFFAOYSA-J octanoate;tin(4+) Chemical compound [Sn+4].CCCCCCCC([O-])=O.CCCCCCCC([O-])=O.CCCCCCCC([O-])=O.CCCCCCCC([O-])=O XZZXKVYTWCYOQX-UHFFFAOYSA-J 0.000 description 1
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000000565 sealant Substances 0.000 description 1
- 229910000077 silane Inorganic materials 0.000 description 1
- 229910052604 silicate mineral Inorganic materials 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 229920002379 silicone rubber Polymers 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- LSZKGNJKKQYFLR-UHFFFAOYSA-J tri(butanoyloxy)stannyl butanoate Chemical compound [Sn+4].CCCC([O-])=O.CCCC([O-])=O.CCCC([O-])=O.CCCC([O-])=O LSZKGNJKKQYFLR-UHFFFAOYSA-J 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
- 125000000026 trimethylsilyl group Chemical group [H]C([H])([H])[Si]([*])(C([H])([H])[H])C([H])([H])[H] 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/04—Polysiloxanes
- C08G77/14—Polysiloxanes containing silicon bound to oxygen-containing groups
- C08G77/16—Polysiloxanes containing silicon bound to oxygen-containing groups to hydroxyl groups
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/04—Polysiloxanes
- C08G77/14—Polysiloxanes containing silicon bound to oxygen-containing groups
- C08G77/18—Polysiloxanes containing silicon bound to oxygen-containing groups to alkoxy or aryloxy groups
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/70—Siloxanes defined by use of the MDTQ nomenclature
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L83/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
- C08L83/04—Polysiloxanes
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D183/00—Coating compositions based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon, with or without sulfur, nitrogen, oxygen, or carbon only; Coating compositions based on derivatives of such polymers
- C09D183/04—Polysiloxanes
Definitions
- the present invention relates to a silicone coating composition, more particularly a composition that is resistant to cracking and dielectric degradation at high temperatures, and a method for preparing the composition.
- High temperature protective coatings and insulating materials to protect a variety of equipment and devices against extremely high temperatures. Heater elements for electric vehicles, exhaust systems for automotive engines, power plants, and top coatings for stoves, for example, all benefit from such protective coatings.
- the coating layers must withstand temperatures exceeding 300 °C over several months without cracking or losing dielectric and insulating properties and must pass aggressive thermal shock tests over a broad temperature range.
- the present invention relates to a composition
- a composition comprising an MQ resin, a ZO-terminated poly(dimethylsiloxane), and mica, wherein the weight-to-weight ratio of the MQ resin to the ZO-terminated poly(dimethylsiloxane) is in the range of from 70:30 to 10:90, and the weight-to-weight ratio of the mica to the sum of the MQ resin and the ZO-terminated poly(dimethylsiloxane) is in the range of from 70:30 to 30:70, where each Z is independently H, Ci-C4-alkyl, or C(O)CH3.
- the composition of the present invention is useful as a coating for a substrate, wherein the coating, when cured, exhibits adhesion and crack-resistance when subjected to high temperatures for hundreds of hours.
- the present invention relates to a composition
- a composition comprising an MQ resin, a ZO-terminated poly (dimethylsiloxane-), and mica, wherein the weight-to- weight ratio of the MQ resin to the ZO-terminated poly(dimethylsiloxane) is in the range of from 70:30 to 10:90, and the weight-to- weight ratio of the mica to the sum of the MQ resin and the ZO-terminated poly(dimethylsiloxane) is in the range of from 70:30 to 30:70, where each Z is independently H, Ci-C 4 -alkyl, or C(O)CH 3 .
- MQ resiri refers to a kinetically stable three-dimensional polymer having repeat units of SiO 4 /2 (Q), and a plurality of tri-Ci-C 4 -alkylsilyl, preferably trimethylsilyl capping groups (M).
- the resin may include additional capping groups such as CiC 4 -alkyl, dimethylhydroxysilyl, and dimethylvinylsilyl capping groups.
- An example of commercially available MQ resins are DOWSILTM MQ-1600, MQ-1601, and MQ-1640 Resins (A Trademark of The Dow Chemical Company or its affiliates).
- ZO-PDMS-OZ The ZO-terminated poly(dimethylsiloxane) (ZO-PDMS-OZ) can be illustrated by the following structure: where n is preferably from 20 or from 40 or from 70 or from 100, to 300 or to 250 or to 200.
- the weight-to-weight ratio of the MQ resin to the ZO-terminated poly(dimethylsiloxane) is in the range of from 70:30 or from 50:50 or from 40:60 to 10:90 or to 20:80 or to 25:75.
- Micas are hydrated aluminum silicate minerals including muscovite, biotite, fuchsite, phlogopite, margarite, glauconite, and lepidolite micas, of which muscovite mica and phlogopite mica are predominant.
- Muscovite mica has a typical composition of K2Al 4 (AhSi602o)(OH) 4 .
- the w/w ratio of the mica to the sum of the of the MQ resin and the ZO-terminated poly(dimethylsiloxane) is in the range of from 70:30 or from 60:40, to 30:70 or 30:60.
- the composition of the present invention advantageously further comprises a crosslinking agent such as a Ci-C 4 -alkyl tri-Ci-C 4 -alkoxy silane, preferably methyltrimethoxysilane (MTMS), and a moisture cure catalyst to promote curing of the composition after it is applied as a coating onto a substrate.
- a crosslinking agent such as a Ci-C 4 -alkyl tri-Ci-C 4 -alkoxy silane, preferably methyltrimethoxysilane (MTMS)
- MTMS methyltrimethoxysilane
- moisture cure catalysts include organotin and organotitanate catalysts such as tin octanoate, tin butanoate, tetraisopropyl titanate, tetra-/?-butyl titanate, and tetra-z-butoxy titanate.
- This curable composition may be prepared by first blending the MQ resin, the ZO-PDMS-OZ, the crosslinking agent, and the moisture cure catalyst in the presence of a solvent to tune the viscosity to a desired level, preferably in the range of from 20 cP or from 50 cP or from 100 cP, to 20,000 cP or to 10,000 cP or to 5,000 cP, or to 1200 cP.
- suitable solvents include aprotic solvents such as ethyl acetate, propyl acetate, butyl acetate, propyl propionate, and hexamethyldisiloxane (HMDS).
- the blend is then advantageously contacted with the mica with additional blending, then applied to a substrate, such as a metal, metal oxide, ceramic, or glass substrate, at a desired coating thickness, typically in the range of from 10 pm or from 20 pm or from 50 pm to 200 pm or to 100 pm.
- a substrate such as a metal, metal oxide, ceramic, or glass substrate
- the coatings are then dried and subjected to thermal aging.
- the present invention is a substrate coated with a composition comprising an MQ-PDMS copolymer and mica.
- composition of the present invention provides a tack-free coating in minutes that is thermally stable to cracking for hundreds or even thousands of hours.
- DOWSILTM MQ-1600 resin Mo.45 Q0.55, 11.0 mole% SiOH
- methyltrimethoxysilane 10 wt %, based on the total weight of the MQ-1600 resin, the silanol-terminated PDMS, and methyltrimethoxy silane
- a sufficient amount of hexamethyldisiloxane to adjust the viscosity of the mixture to 500 cp to 2000 cp were added to a dry flask under nitrogen.
- Aluminum panels (3” x 6”) were washed with toluene and acetone, then dried. A portion of the composition was applied at a thickness of 50 pm to 100 pm using a 4-mil drawdown bar.
- the panels coated with the example formulations containing mica became tack free in 10 min at room temperature, while the panel coated with the mica-free formulation (Cl) became tack free in 1 h.
- Each sample was then heated in an oven at 300 °C. Film cracking time was recorded (in days) as the first instance of visible cracks in the coatings.
- Table 1 shows the thermal stability of coatings as measured by crack time.
- the mica weight percent is based on the sum of the weights of the MQ resin, the HO-PDMS-OH, and the mica.
- MQ resin and HO-PDMS-OH weight percentages are based on the sum of the MQ resin and HO-PDMS-OH.
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Wood Science & Technology (AREA)
- Paints Or Removers (AREA)
Abstract
The present invention relates to a composition comprising an MQ resin, a ZO-terminated poly(dimethylsiloxane), and mica. The composition is useful as a coating on a substrate, wherein the coating exhibits adhesion, uniformity, and crack resistance when subjected to high temperatures for hundreds or even thousands of hours.
Description
Silicone Coating Composition with Mica
Background of the Invention
The present invention relates to a silicone coating composition, more particularly a composition that is resistant to cracking and dielectric degradation at high temperatures, and a method for preparing the composition. High temperature protective coatings and insulating materials to protect a variety of equipment and devices against extremely high temperatures. Heater elements for electric vehicles, exhaust systems for automotive engines, power plants, and top coatings for stoves, for example, all benefit from such protective coatings. In many applications, the coating layers must withstand temperatures exceeding 300 °C over several months without cracking or losing dielectric and insulating properties and must pass aggressive thermal shock tests over a broad temperature range.
High temperature resistance of silicones ostensibly makes them promising candidates as high temperature protective coatings and sealants; nevertheless, silicone rubbers are not resistant to cracking above 250 °C beyond 3 weeks. The combination of silicone and inorganic filler such as SiO2, TiO2, and AI2O3 provides a composition with long term high temperature resistance; however, coatings prepared from such compositions require aging at temperatures exceeding 500 °C to form ceramic-like coatings. At such extreme temperatures, the coatings are likely to crack and suffer thermal shock failure; moreover, electronic elements beneath the surface of the coating are vulnerable to damage. It would therefore be an advance in the field of high temperature protective coatings to develop a composition that provides a coating that is resistant to cracking, delamination, and thermal shock failure, while maintaining acceptable dielectric properties at temperatures exceeding 300 °C for an extended period.
Summary of the Invention
In one aspect, the present invention relates to a composition comprising an MQ resin, a ZO-terminated poly(dimethylsiloxane), and mica, wherein the weight-to-weight ratio of the MQ resin to the ZO-terminated poly(dimethylsiloxane) is in the range of from 70:30 to 10:90, and the weight-to-weight ratio of the mica to the sum of the MQ resin and the ZO-terminated poly(dimethylsiloxane) is in the range of from 70:30 to 30:70, where each Z is independently H, Ci-C4-alkyl, or C(O)CH3. The composition of the present invention is useful as a coating for a substrate, wherein the coating, when cured, exhibits adhesion and crack-resistance when subjected to high temperatures for hundreds of hours.
Detailed Description of the Invention
The present invention relates to a composition comprising an MQ resin, a ZO-terminated poly (dimethylsiloxane-), and mica, wherein the weight-to- weight ratio of the MQ resin to the ZO-terminated poly(dimethylsiloxane) is in the range of from 70:30 to 10:90, and the weight-to- weight ratio of the mica to the sum of the MQ resin and the ZO-terminated poly(dimethylsiloxane) is in the range of from 70:30 to 30:70, where each Z is independently H, Ci-C4-alkyl, or C(O)CH3.
As used herein, the term “MQ resiri’ refers to a kinetically stable three-dimensional polymer having repeat units of SiO4/2 (Q), and a plurality of tri-Ci-C4-alkylsilyl, preferably trimethylsilyl capping groups (M). The resin may include additional capping groups such as CiC4-alkyl, dimethylhydroxysilyl, and dimethylvinylsilyl capping groups. An example of commercially available MQ resins are DOWSIL™ MQ-1600, MQ-1601, and MQ-1640 Resins (A Trademark of The Dow Chemical Company or its Affiliates).
The ZO-terminated poly(dimethylsiloxane) (ZO-PDMS-OZ) can be illustrated by the following structure:
where n is preferably from 20 or from 40 or from 70 or from 100, to 300 or to 250 or to 200.
The weight-to-weight ratio of the MQ resin to the ZO-terminated poly(dimethylsiloxane) is in the range of from 70:30 or from 50:50 or from 40:60 to 10:90 or to 20:80 or to 25:75.
Micas are hydrated aluminum silicate minerals including muscovite, biotite, fuchsite, phlogopite, margarite, glauconite, and lepidolite micas, of which muscovite mica and phlogopite mica are predominant. Muscovite mica has a typical composition of K2Al4(AhSi602o)(OH)4. The w/w ratio of the mica to the sum of the of the MQ resin and the ZO-terminated poly(dimethylsiloxane) is in the range of from 70:30 or from 60:40, to 30:70 or 30:60.
The composition of the present invention advantageously further comprises a crosslinking agent such as a Ci-C4-alkyl tri-Ci-C4-alkoxy silane, preferably methyltrimethoxysilane (MTMS), and a
moisture cure catalyst to promote curing of the composition after it is applied as a coating onto a substrate. Examples of moisture cure catalysts include organotin and organotitanate catalysts such as tin octanoate, tin butanoate, tetraisopropyl titanate, tetra-/?-butyl titanate, and tetra-z-butoxy titanate. This curable composition may be prepared by first blending the MQ resin, the ZO-PDMS-OZ, the crosslinking agent, and the moisture cure catalyst in the presence of a solvent to tune the viscosity to a desired level, preferably in the range of from 20 cP or from 50 cP or from 100 cP, to 20,000 cP or to 10,000 cP or to 5,000 cP, or to 1200 cP. Examples of suitable solvents include aprotic solvents such as ethyl acetate, propyl acetate, butyl acetate, propyl propionate, and hexamethyldisiloxane (HMDS). The blend is then advantageously contacted with the mica with additional blending, then applied to a substrate, such as a metal, metal oxide, ceramic, or glass substrate, at a desired coating thickness, typically in the range of from 10 pm or from 20 pm or from 50 pm to 200 pm or to 100 pm. The coatings are then dried and subjected to thermal aging.
During thermal aging, at least some portion of the MQ resin is observed to react with at least some portion of ZO-PDMS-OZ to form an MQ-PDMS copolymer. Thus, in another aspect, the present invention is a substrate coated with a composition comprising an MQ-PDMS copolymer and mica.
The composition of the present invention provides a tack-free coating in minutes that is thermally stable to cracking for hundreds or even thousands of hours.
Examples 1-5 - Preparation of Blend of MQ resin, Silanol-terminated PDMS, and Mica
DOWSIL™ MQ-1600 resin (Mo.45 Q0.55, 11.0 mole% SiOH), silanol-terminated PDMS (HO-PDMS-OH dp = 80), methyltrimethoxysilane (10 wt %, based on the total weight of the MQ-1600 resin, the silanol-terminated PDMS, and methyltrimethoxy silane), and a sufficient amount of hexamethyldisiloxane to adjust the viscosity of the mixture to 500 cp to 2000 cp were added to a dry flask under nitrogen. The mixture was stirred for 30 min, after which time mica, which had been dried in vacuo at 120 °C for 3 to 20 h then cooled to room temperature under nitrogen, was added to the mixture with stirring under nitrogen. MRX muscovite mica (MRX, median particle size 11.4 pm, obtained from Arctic Minerals) was used for Examples 1, 2, and 3, and C-4000 muscovite mica (C-4000, median particle size 10.8 pm, obtained from IMERYS) was used for examples 4 and 5. Tetraisopropyl titanate (1 wt% based on the weight of the formulation) was added to each sample with stirring. The comparative example formulation (Cl) did not include mica.
Long Term High Temperature Resistance Testing
Aluminum panels (3” x 6”) were washed with toluene and acetone, then dried. A portion of the composition was applied at a thickness of 50 pm to 100 pm using a 4-mil drawdown bar. The panels coated with the example formulations containing mica became tack free in 10 min at room temperature, while the panel coated with the mica-free formulation (Cl) became tack free in 1 h. Each sample was then heated in an oven at 300 °C. Film cracking time was recorded (in days) as the first instance of visible cracks in the coatings.
Table 1 shows the thermal stability of coatings as measured by crack time. The mica weight percent is based on the sum of the weights of the MQ resin, the HO-PDMS-OH, and the mica. MQ resin and HO-PDMS-OH weight percentages are based on the sum of the MQ resin and HO-PDMS-OH.
Table 1 - Thermal Stability of Coatings
The data show that the cured coatings containing mica exhibit a dramatic resistance to cracking and delamination. Also, samples containing mica cured much faster than the sample without mica. The combination of the MQ resin and mica alone was found to fail the cracking test within 2 d, while the combination of the HO-PDMS-OH and mica alone delaminated readily from the substrate at 300 °C. Moreover, of the fillers tested - silica, calcium carbonate, aluminum silicate, calcium silicate, alumina, ferric oxide, and mica - mica was found to be the only class of fillers to exhibit crack times beyond 120 h.
Claims
1. A composition comprising an MQ resin, a ZO-terminated poly (dimethylsiloxane), and mica, wherein the weight-to-weight ratio of the MQ resin to the ZO-terminated poly(dimethylsiloxane) is in the range of from 70:30 to 10:90, and the weight-to-weight ratio of the mica to the sum of the MQ resin and the ZO-terminated poly(dimethylsiloxane) is in the range of from 70:30 to 30:70, where each Z is independently H, Ci-C4-alkyl, or C(O)CH3.
2. The composition of Claim 1 wherein Z is H, and the ZO-terminated poly(dimethylsiloxane) has a degree of polymerization in the range of from 20 to 300.
3. The composition of Claim 2 wherein the mica is a muscovite or phlogopite mica, and wherein the weight-to-weight ratio of the mica to the sum of the MQ resin and the HO-terminated poly(dimethylsiloxane) is in the range of from 60:40 to 30:60.
4. The composition of Claim 3 wherein the weight-to-weight ratio of the MQ resin to the HO-terminated poly(dimethylsiloxane) is in the range of from 50:50 to 20:80.
5. The composition of Claim 3 wherein the mica is muscovite mica and the weight-to-weight ratio of the MQ resin to the ZO-terminated poly (dimethylsiloxane) is in the range of from 40:60 to 25:75.
6. The composition of any of Claims 1 to 5 which further comprises a crosslinking agent, a moisture cure catalyst, and a solvent.
7. The composition of Claim 6 wherein the crosslinking agent is methyltrimethoxysilane, the moisture cure catalyst is an organotin or an organotitanate catalyst, and the solvent is ethyl acetate, propyl acetate, butyl acetate, propyl propionate, or hexamethyldisiloxane.
8. An article comprising a substrate coated with the composition of Claim 6.
9. The article of Claim 8 wherein the substrate is a metal, a metal oxide, a ceramic, or glass.
10. The article of Claim 9 wherein the crosslinking agent is methyltrimethoxysilane, the moisture cure catalyst is an organotin or an organotitanate catalyst, and the solvent is ethyl acetate, propyl acetate, butyl acetate, propyl propionate, or hexamethyldisiloxane.
11. The article of Claim 10 wherein the coating is cured.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US202263419744P | 2022-10-27 | 2022-10-27 | |
| US63/419,744 | 2022-10-27 |
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| WO2024091798A1 true WO2024091798A1 (en) | 2024-05-02 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/US2023/076643 WO2024091798A1 (en) | 2022-10-27 | 2023-10-12 | Silicone coating composition with mica |
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| Country | Link |
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| WO (1) | WO2024091798A1 (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4800127A (en) * | 1987-03-26 | 1989-01-24 | General Electric Company | Thermal shock resistant silicone coating composition |
| US4929703A (en) * | 1989-03-30 | 1990-05-29 | Dow Corning Corporation | Solventless silicone coating composition |
| JP2020026492A (en) * | 2018-08-14 | 2020-02-20 | モメンティブ・パフォーマンス・マテリアルズ・ジャパン合同会社 | Room temperature curable polyorganosiloxane composition and cured product thereof |
-
2023
- 2023-10-12 WO PCT/US2023/076643 patent/WO2024091798A1/en unknown
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4800127A (en) * | 1987-03-26 | 1989-01-24 | General Electric Company | Thermal shock resistant silicone coating composition |
| US4929703A (en) * | 1989-03-30 | 1990-05-29 | Dow Corning Corporation | Solventless silicone coating composition |
| JP2020026492A (en) * | 2018-08-14 | 2020-02-20 | モメンティブ・パフォーマンス・マテリアルズ・ジャパン合同会社 | Room temperature curable polyorganosiloxane composition and cured product thereof |
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