Silicone release coating emulsion, method for preparation thereof, and use on bakery paper - Patents.com

Abstract

The silicone release coating emulsion comprises a curable silicone release coating composition dispersed in an aqueous phase. The silicone release coating emulsion can be coated onto a substrate (such as paper) to form a wet deposit, dried to form a layer of the silicone release coating composition on the substrate, and cured to form a silicone release coating on the surface of the substrate. The coated substrate is useful in food contact applications such as bakery release.

Description

[Technical field]

[0001] Cross-references to related applications and statements regarding federally funded research This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 63 / 304,004, filed January 28, 2022. U.S. Provisional Patent Application No. 63 / 304,004 is incorporated herein by reference.

[0002] The present invention relates to silicone release coating emulsions and their preparation and use. More specifically, the silicone release coating emulsions are aqueous emulsions that include an aqueous continuous phase having a silicone release coating composition dispersed therein, and are curable to form silicone release coatings suitable for use on a variety of substrates, including paper for food contact applications.

[0003] Introduction The curable silicone composition can be coated on a substrate and cured to form a coating that improves or changes various properties of the substrate. The substrate to which the composition is applied can include one or more materials. Such materials can be fibrous or cellulosic, for example, paper substrates such as paper or cardboard. The paper can be polished or unpolished, calendered or uncalendered. Alternatively, instead of a paper substrate, the substrate can be a plastic substrate, including, for example, acrylic, polycarbonate, or polyethylene terephthalate materials, or the substrate can be a laminate including paper and plastic.

[0004] Curable silicone compositions can be water-based, solvent-based, or solventless compositions.Solventless compositions, such as SYL-OFF 7000 Coating from Dow Silicones Corporation (Midland, Michigan, USA), can be applied at relatively high thicknesses (≧1 μm) and have the disadvantage that they cannot be coated at reduced thicknesses using existing coating machines.Furthermore, due to the relatively high viscosity of solventless compositions, undesirable misting during processing and surface defects in the resulting coating can occur, especially at high production speeds.

[0005] Thus, aqueous compositions may be desirable in some applications, such as those requiring a well-controlled low thickness deposition and those bound by indirect food regulations (e.g. food contact applications). Coated papers suitable for food contact applications can be obtained by treating the paper substrate with a compound or composition to form a layer on the paper. Known treatments are based on fluorinated compounds that can provide non-stick properties by forming a film with low surface energy, which is resistant to chemicals, thereby providing the treated paper with oil, grease and water repellency. However, environmental and health concerns have been raised about fluorinated compounds, which tend to limit or prohibit their use by various regulations in the food packaging industry.

[0006] Another approach has been to treat paper substrates with a mixture of polyvinyl alcohol and chromate-fatty acid complexes. However, the use of heavy metals such as chromium has also raised environmental and health concerns in food packaging related applications. Other treatments can impart some oleophobicity to paper, but often require relatively large amounts of material to be effective and form thick coatings on the paper that can be detrimental to mechanical properties and durability when the paper is creased or folded. Furthermore, using large amounts of material may not be cost-effective. Summary of the Invention

[0007] The silicone release coating emulsion comprises (A) an aliphatically unsaturated polyorganosiloxane, (B) a polyorganohydrogensiloxane, (C) a hydrosilylation reaction catalyst, (D) a hydrosilylation reaction inhibitor, (E) water, (F) a buffer solution, and (G) an alkenyloxy polyether. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The silicone release coating emulsion (emulsion) may optionally further comprise an additional starting material selected from the group consisting of (H) a polyvinyl alcohol compound, (I) a biocide, (J) an antifoaming agent, (K) a non-functional polyorganosiloxane, and (L) a combination of two or more of the starting materials (H)-(K). Alternatively, the emulsion may consist essentially of (A) an aliphatically unsaturated polyorganosiloxane, (B) a polyorganohydrogensiloxane, (C) a hydrosilylation reaction catalyst, (D) a hydrosilylation reaction inhibitor, (E) water, (F) a buffer, and (G) an alkenyloxy polyether, and optionally an additional starting material selected from the group consisting of (H) a polyvinyl alcohol compound, (I) a biocide, (J) an antifoaming agent, (K) a non-functional polyorganosiloxane, and (L) a combination of two or more of (H)-(K). Alternatively, the emulsion may be comprised of (A) an aliphatically unsaturated polyorganosiloxane, (B) a polyorganohydrogensiloxane, (C) a hydrosilylation reaction catalyst, (D) a hydrosilylation reaction inhibitor, (E) water, (F) a buffer, (G) an alkenyloxy polyether, and optionally, additional starting materials selected from the group consisting of (H) a polyvinyl alcohol compound, (I) a biocide, (J) an antifoam agent, (K) a non-functional polyorganosiloxane, and (L) a combination of two or more of (H)-(K).

[0009] (A) Aliphatic unsaturated polyorganosiloxane The starting material (A) in the above emulsion is an aliphatically unsaturated polyorganosiloxane. The aliphatically unsaturated polyorganosiloxane of the starting material (A) has the unit formula (AI): (R1 3SiO 1 / 2 ) i (R 1 2R 3 SiO 1 / 2 ) f (R 1 2SiO 2 / 2 ) g (R 1 R 3 SiO 2 / 2 ) h (SiO 4 / 2 ) j wherein each R 1 are independently selected alkyl or aryl groups, and each R 3 are independently selected alkenyl groups, and the subscripts i, f, g, h, and j represent the average number of each siloxane unit in formula (AI), with the subscript i having a value from 0 to 4, the subscript f from 0 to 4, the subscript g from 0 to 1400, the subscript h from 0 to 200, and the subscript j from 0 or 1, with the proviso that when the amount (i+f)=2 to 4, the amount (f+h)≧2, and the amount (i+f+g+h) is 15 to 1400. Alternatively, the subscript g may be 0 to 1200. The aliphatically unsaturated polyorganosiloxane may be linear (when j=0) or branched (when j>0).

[0010] R 1 Suitable alkyl groups for R may have 1 to 8 carbon atoms, such as methyl, ethyl, propyl (including isopropyl and n-propyl), butyl (including n-butyl, t-butyl, sec-butyl, and isobutyl), pentyl (including linear, branched, and cyclic saturated hydrocarbon groups having 5 carbon atoms), hexyl (including linear, branched, and cyclic saturated hydrocarbon groups having 6 carbon atoms), heptyl (including linear, branched, and cyclic saturated hydrocarbon groups having 7 carbon atoms), and octyl (including linear, branched, and cyclic saturated hydrocarbon groups having 8 carbon atoms). 1 Suitable aryl groups within R may have 6 to 20 carbon atoms, such as phenyl, tolyl, xylyl, naphthyl, and styryl. Alternatively, the aryl group may be phenyl. Alternatively, each R 1may be methyl or ethyl. Alternatively, each R 1 may be methyl or phenyl. Alternatively, each R 1 can be methyl.

[0011] R 3 Suitable alkenyl groups for R are vinyl, allyl, and hexenyl. 3 may be selected from the group consisting of vinyl and allyl. 3 may be selected from the group consisting of vinyl and hexenyl. Alternatively, each R 3 may be vinyl.

[0012] Alternatively, when the subscript j=0, the aliphatically unsaturated polyorganosiloxane may be linear. The linear aliphatically unsaturated polyorganosiloxane has the unit formula (A-II): (R 1 3SiO 1 / 2 ) i (R 1 2R 3 SiO 1 / 2 ) f (R 1 2SiO 2 / 2 ) g (R 1 R 3 SiO 2 / 2 ) h wherein R 1 are independently selected alkyl or aryl groups as defined above, and R 3 are independently selected alkenyl groups as defined above, the subscript i is 0, 1, or 2, the subscript f is 0, 1, or 2, the subscript g is 0 to 1200, and the subscript h is 0 to 200, with the proviso that when the amount (i+f)=2, the amount (f+h)≧2 and the amount (i+f+g+h) is 15 to 1200.

[0013] Alternatively, the linear aliphatically unsaturated polyorganosiloxane may comprise a bis-alkenyl endblocked polydialkylsiloxane, where i=0, f=2, and h=0. The bis-alkenyl endblocked polydialkylsiloxane has the unit formula (A-III): (R 1 2R3 SiO 1 / 2 )2(R 1 2SiO 2 / 2 ) g wherein each R 1 is an alkyl group, and each R 3 is an alkenyl group, and the subscript g is 15 to 1200.

[0014] Alternatively, the linear aliphatically unsaturated polyorganosiloxane may include a poly(dialkyl / alkylvinyl)siloxane (where g>0 and h>0). The poly(dialkyl / alkylvinyl)siloxane has the unit formula (A-IV): (R 3 R 1 2SiO 1 / 2 )2(R 1 2SiO 2 / 2 ) g (R 1 R 3 SiO 2 / 2 ) h wherein each R 1 is an alkyl group, and each R 3 is an alkenyl group, the subscript g is greater than 0 and is 1200, and the subscript h is 2 to 200.

[0015] Alternatively, the starting material (A) may comprise a linear aliphatically unsaturated polyorganosiloxane such as: i) α,ω-dimethylvinylsiloxy-terminated polydimethylsiloxane, ii) α,ω-dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylvinylsiloxane); iii) α,ω-dimethylvinylsiloxy-terminated polymethylvinylsiloxane; iv) α,ω-trimethylsiloxy-terminated poly(dimethylsiloxane / methylvinylsiloxane); v) α,ω-trimethylsiloxy-terminated polymethylvinylsiloxane, vi) α,ω-dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylphenylsiloxane / methylvinylsiloxane); vii) α,ω-dimethylvinylsiloxy terminated poly(dimethylsiloxane / methylphenylsiloxane); viii) α,ω-dimethylvinylsiloxy-terminated poly(dimethylsiloxane / diphenylsiloxane); ix) α,ω-phenyl, methyl, vinyl-siloxy terminated polydimethylsiloxane; x) may include a combination of two or more of i) to ix).

[0016] Methods for preparing the linear aliphatically unsaturated polydiorganosiloxanes described above for starting material (A), such as the hydrolysis and condensation of the corresponding organohalosilanes and oligomers, or the equilibration of cyclic polydiorganosiloxanes, are known in the art, see, for example, U.S. Pat. Nos. 3,284,406, 4,772,515, 5,169,920, 5,317,072, and 6,956,087.

[0017] In addition to (or instead of) the linear aliphatically unsaturated polydiorganosiloxane described above, the starting material (A) may include a branched aliphatically unsaturated polyorganosiloxane. The branched aliphatically unsaturated polyorganosiloxane may have from greater than 0 to 5 mole percent of tetrafunctional units relative to the branched aliphatically unsaturated polyorganosiloxane. For example, the branched aliphatically unsaturated polyorganosiloxane may have a unit formula (AV): (R 1 3SiO 1 / 2 ) i (R 1 2R 3 SiO 1 / 2 ) f (R 1 2SiO 2 / 2 ) g (SiO 4 / 2 ) j wherein R 1 and R 3is as above, and the subscripts i, f, g, and j have average values ​​such that 2≧i≧0, 4≧f≧0, 995≧g≧4, j=1, (i+f)=4, and (i+f+g+j)>50. Alternatively, the amount (i+f+g+j) may have a value sufficient to impart a viscosity, as measured by a rotational viscometer (described below along with the test method), of >170 mPa·s. Alternatively, the viscosity may be >170 mPa·s to 1000 mPa·s, alternatively >170 to 500 mPa·s, alternatively 180 mPa·s to 450 mPa·s, alternatively 190 mPa·s to 420 mPa·s. Suitable branched, aliphatically unsaturated polyorganosiloxanes for starting material (A) are known in the art and can be made by known methods, exemplified by those disclosed in U.S. Pat. No. 6,806,339 and U.S. Patent Application Publication No. 2007 / 0289495.

[0018] (B) Polyorganohydrogensiloxane The starting material (B) in the emulsion is a polyorganohydrogensiloxane. The polyorganohydrogensiloxane has the unit formula (BI): (R 1 3SiO 1 / 2 ) w (R 1 2HSiO 1 / 2 ) x (R 1 2SiO 2 / 2 ) y (R 1 HSiO 2 / 2 ) z wherein R 1are as above, and the subscripts w, x, y, and z represent the average number of each siloxane per molecule, with values ​​such that w is 0, 1, or 2, subscript x is 0, 1, or 2, subscript y is 0 to 250, and subscript z is 1 to 250, with the proviso that the amount (w+x)=2, the amount (x+z)≧2, and the amount (w+x+y+z) is 10 to 300. Alternatively, the subscript w may be 2 and the subscript x may be 0. Alternatively, the subscript y may be greater than 0 to 250. Alternatively, the amount (x+z)≧3 when the aliphatically unsaturated polyorganosiloxane (A) has two silicon-bonded alkenyl groups per molecule, for example when (A) is i) an α,ω-dimethylvinylsiloxy-terminated polydimethylsiloxane.

[0019] Alternatively, when x=y=0 and w=2, (B) polyorganohydrogensiloxane has the unit formula (B-II): (R 1 3SiO 1 / 2 )2(R 1 HSiO 2 / 2 ) z wherein R 1 is as defined above, and z is an integer from 3 to 250.

[0020] Polyorganohydrogensiloxanes suitable for use herein are exemplified by the following: (i) α,ω-dimethylhydrogensiloxy-terminated poly(dimethylsiloxane / methylhydrogensiloxane), (ii) α,ω-dimethylhydrogensiloxy-terminated polymethylhydrogensiloxane, (iii) α,ω-trimethylsiloxy-terminated poly(dimethylsiloxane / methylhydrogensiloxane); (iv) α,ω-trimethylsiloxy-terminated polymethylhydrogensiloxane, and (v) α-dimethylhydrogensiloxy, ω-trimethylsiloxy terminated poly(dimethylsiloxane / methylhydrogensiloxane); (vi) α-dimethylhydrogensiloxy, ω-trimethylsiloxy terminated polymethylhydrogensiloxane, (vii) α,ω-dimethylhydrogensiloxy-terminated polydimethylsiloxane, and (viii) A combination of two or more of these.

[0021] Polyorganohydrogensiloxanes are also commercially available, such as those available from Gelest, Inc. (Morrisville, Pennsylvania, USA), including, for example, HMS-H271, HMS-071, HMS-993, HMS-301, HMS-301 R, HMS-031, HMS-991, HMS-992, HMS-993, HMS-082, HMS-151, HMS-013, HMS-053, and HMS-HM271. Methods for preparing linear and branched polyorganohydrogensiloxanes suitable for use herein, such as the hydrolysis and condensation of organohalosilanes, are well known in the art, as exemplified by U.S. Pat. Nos. 2,823,218 to Speier, 3,957,713 to Jeram et al., and 4,329,273 to Hardman et al.

[0022] The polyorganohydrogensiloxane starting material (B) is used in the emulsion in an amount sufficient to provide a molar ratio of silicon-bonded hydrogen atoms in starting material (B) to the amount of alkenyl groups in starting material (A) (i.e., the SiH:SiVi ratio) of from 1.2:1 to 3.0:1, alternatively from 1.4:1 to 2.5:1.

[0023] (C) Hydrosilylation reaction catalyst The starting material (C) in the emulsion is a hydrosilylation reaction catalyst. The catalyst promotes the reaction between the alkenyl groups in the starting material (A) and the silicon-bonded hydrogen atoms in the starting material (B). The catalyst may comprise a metal selected from Fe, Ni, Co, Zr, Ti, or a platinum group metal. Alternatively, the metal may comprise a platinum group metal. The platinum group metal may be selected from the group consisting of platinum, rhodium, ruthenium, palladium, osmium, and iridium. Alternatively, the platinum group metal may be platinum. The hydrosilylation reaction catalyst may be (CI) a radiation-activated catalyst, i.e., capable of catalyzing the hydrosilylation reaction after irradiation (such as exposure to actinic radiation, e.g., exposure to visible or ultraviolet light), (C-II) a hydrosilylation catalyst that is activatable by means other than irradiation, e.g., capable of catalyzing the hydrosilylation reaction without irradiation, such as heating, or (C-III) a combination of both (CI) and (C-II).

[0024] Suitable radiation-activatable catalysts for use as starting materials (CI) can be activated by exposure to radiation having a wavelength between 200 nm and 500 nm. Suitable radiation-activated hydrosilylation reaction catalysts include cyclopentadienyl platinum complexes (e.g., η5-cyclopentadienyl)tri(α-alkyl)platinum(IV)), cyclopentadienyltrimethylplatinum and trimethyl(methylcyclopentadienyl)platinum(IV), cyclooctadienyl platinum complexes (e.g., η4-1,5-cyclooctadiene diaryl platinum complexes), and Pt(II)-β-diketonate complexes (e.g., bis(acetylacetonato)platinum(II)). Examples of cyclopentadienyl platinum complexes are known in the art and are disclosed, for example, in U.S. Patent No. 4,510,094 to Drahnak, U.S. Patent No. 4,600,484 to Drahnak, U.S. Patent No. 4,916,169 to Boardman et al., U.S. Patent No. 6,127,446 to Butts, U.S. Patent No. 6,451,869 to Butts, U.S. Patent No. 6,376,569 to Oxman et al., U.S. Patent No. 8,088,878 to Koellnberger, and Chinese Patent No. 101925608(B).Cyclooctadienyl platinum complexes are disclosed, for example, in U.S. Patent No. 6,046,250 to Boardman et al. Platinum(II) β-diketonate catalysts are disclosed, for example, in European Patent No. 0398701 (B1) to Oxman et al., U.S. Patent No. 8,642,674 to Ikeno, and Chinese Patent No. 10403160 (2A). U.S. Patent Application Publication Nos. 2005 / 0154079 to Walker et al., 2011 / 0171400 (A1) to Thompson et al., and 03865638 (B2) to Ikeno each similarly disclose various radiation-activated hydrosilylation reaction catalysts.

[0025] Alternatively, the hydrosilylation reaction catalyst may be (C-II) a hydrosilylation catalyst that can be activated by means other than irradiation. For example, (C-II) may be (C-II-1) the platinum group metals mentioned above, (C-II-2) compounds of such metals, such as chlorotris(triphenylphosphine)rhodium(I) (Wilkinson's catalyst), rhodium diphosphine chelates, such as [1,2-bis(diphenylphosphino)ethane]dichlorodirhodium or [1,2-bis(diethylphospino)ethane]dichlorodirhodium, chloroplatinic acid (Speier's catalyst), chloroplatinic acid hexahydrate, platinum dichloride, and (C-II-3) complexes of compounds, (C-II-2) alkenyl-functional organopolysiloxane oligomers, such as alkenyl-functional polydialkylsiloxanes, or (C-II-4) platinum group metal compounds microencapsulated in matrices or core-shell structures. Complexes of platinum with alkenyl-functional organopolysiloxane oligomers include the complex of platinum with 1,3-diethyl-1,1,3,3-tetramethyldisiloxane (Karstedt's catalyst) and the Pt(0) complex in tetramethyltetravinylcyclotetrasiloxane (Ashby's complex). Alternatively, the hydrosilylation reaction catalyst may be a compound or complex as described above (C-II-5) microencapsulated in a resin matrix. Specific examples of suitable platinum-containing catalysts in (C-II) include chloroplatinic acid, either in hexahydrate form or in anhydrous form, and / or platinum-containing catalysts obtained by a process comprising reacting chloroplatinic acid with an aliphatically unsaturated organosilicon compound such as divinyltetramethyldisiloxane, or the alkene-platinum-silyl complexes described in Roy's U.S. Pat. No. 6,605,734. An alkene-platinum-silyl complex can be prepared, for example, by mixing 0.015 moles of (COD)PtCl2 with 0.045 moles of COD and 0.0612 moles of HMeSiCl2 (where COD represents cyclooctadienyl and Me represents methyl).Other exemplary hydrosilylation reaction catalysts are disclosed in U.S. Pat. Nos. 2,823,218 to Speier, 3,159,601 to Ashby, 3,220,972 to Lamoreaux, 3,296,291 to Chalk et al., 3,419,593 to Willing, 3,516,946 to Modic, 3,814,730 to Karstedt, 3,928,629 to Chandra, 3,989,668 to Lee et al., and 4,766,176 to Lee et al. Nos. 4,784,879 to Lee et al., 5,017,654 to Togashi, 5,036,117 to Chung et al., and 5,175,325 to Brown et al., and European Patent No. EP 0347895(A) to Togashi et al., and U.S. Patent Application No. 2019 / 0367744 to Chevalier et al. disclose both (C-II) radiation activatable catalysts and (C-II) catalysts activatable by means other than radiation (e.g., thermally activatable catalysts). Other hydrosilylation reaction catalysts that can be used herein are as disclosed in "Hydrosilylation reaction of olefins: recent advances and perspectives" by Y. Nakajima and S. Shimada, RSC Adv., 2015, 5, 20603-20616, and "Hydrosilylation, Advances in Silicon Science", Chapter 1, Hydrosilylation of Alkenes and Their Derivatives, B. Marciniec (ed.). DOI 10.1007 / 978-1-4020-8172-9 1, (Copyright) Springer Science+Business Media BV2009 (pp.2-49). Suitable platinum hydrosilylation catalysts for the starting material (C-II) are commercially available, for example, SYL-OFF™ 4000 catalyst and SYL-OFF™ 2700 are available from Dow Silicones Corporation (Midland, Michigan, USA).

[0026] The starting material (C) may be one hydrosilylation catalyst or a combination of two or more of the above hydrosilylation catalysts. For example, the starting material (C) may be a combination of (CI) and (C-II), for example, when both exposure to radiation and heating are used in the hydrosilylation reaction. Alternatively, the starting material (C) may be a combination of two or more radiation-activatable catalysts, such as a combination of a cyclopentadienyl platinum complex and a Pt(II)-β-diketonate complex. Those skilled in the art will recognize that a particular catalyst species may be activated by either irradiation or heating, as described herein, and that when a combination of two or more catalysts is used, the selected catalyst species will differ from each other.

[0027] The amount of (C) hydrosilylation reaction catalyst in the emulsion will depend on a variety of factors, including the selection of starting materials (A) and (B), the respective contents of alkenyl groups and silicon-bonded hydrogen atoms, and the amount of (D) hydrosilylation reaction inhibitor in the composition. However, the amount of catalyst will be sufficient to catalyze the hydrosilylation reaction of SiH groups and alkenyl groups, or the amount of catalyst will be sufficient to provide at least 10 ppm, alternatively at least 15 ppm, alternatively at least 20 ppm, alternatively at least 50 ppm, and alternatively at least 100 ppm, by weight of platinum group metal, based on the combined amount of starting materials (A), (B), (C), (D), (E), (F), and (G) in the emulsion. At the same time, the amount of catalyst is sufficient to provide up to 1,000 ppm, alternatively up to 800 ppm, alternatively up to 500 ppm, alternatively up to 100 ppm, of platinum group metal on a weight basis based on the combined weight of starting materials (A) and (B) in the emulsion.

[0028] (D) Hydrosilylation Reaction Inhibitors The starting material (D) in the emulsion is a hydrosilylation reaction inhibitor (inhibitor). Inhibitors can be used to change the hydrosilylation reaction compared to silicone release coating compositions containing the same starting materials except for the inhibitor. Starting material (D) can be, for example, (D1) acetylenic alcohols, (D2) silylated acetylenic alcohols, (D3) ene-yne ​​compounds, (D4) triazoles, (D5) phosphines, (D6) mercaptans, (D7) hydrazines, (D8) amines, (D9) fumarates, (D10) maleates, (D11) ethers, (D12) carbon monoxide, (D13) alkenyl-functional siloxane oligomers, and (D14) combinations of two or more thereof. Alternatively, the hydrosilylation reaction inhibitor may be selected from the group consisting of (D1) acetylenic alcohols, (D2) silylated acetylenic alcohols, (D9) fumarates, (D10) maleates, (D13) combinations of two or more thereof. Alternatively, the hydrosilylation reaction inhibitor may be selected from the group consisting of (D1) acetylenic alcohols, (D2) silylated acetylenic compounds, (D9) fumarates, (D10) maleates, (D13) carbon monoxide, and (D14) combinations of two or more thereof. Alternatively, the hydrosilylation reaction inhibitor may be an acetylenic alcohol.

[0029] The acetylenic alcohol is exemplified by 3,5-dimethyl-1-hexyn-3-ol, 1-butyn-3-ol, 1-propyn-3-ol, 2-methyl-3-butyn-2-ol, 3-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol, 3-phenyl-1-butyn-3-ol, 4-ethyl-1-octyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, and 1-ethynyl-1-cyclohexanol, and combinations thereof. Alternatively, the inhibitor may be a silylated acetylenic compound. Without being bound by theory, it is believed that the addition of a silylated acetylenic compound reduces the yellowing of the reaction product prepared from the hydrosilylation reaction compared to the reaction product from the hydrosilylation of a starting material that does not contain a silylated acetylenic compound or that contains an organic acetylenic alcohol inhibitor such as those described above.The silylated acetylene compounds are (3-methyl-1-butyne-3-oxy)trimethylsilane, ((1,1-dimethyl-2-propynyl)oxy)trimethylsilane, bis(3-methyl-1-butyne-3-oxy)dimethylsilane, bis(3-methyl-1-butyne-3-oxy)silanemethylvinylsilane, bis((1,1-dimethyl-2-propynyl)oxy)dimethylsilane, methyl(tris(1,1-dimethyl-2-propynyloxy))silane, methyl(tris(3-methyl-1-butyne-3-oxy))silane, (3-methyl-1-butyne-3-oxy)dimethylphenylsilane, (3-methyl-1-butyne-3-oxy)dimethylhexenylsilane, (3-methyl-1-butyne-3-oxy)triethylsilane, bis(3-methyl-1- silane, (3,5-dimethyl-1-hexyne-3-oxy)trimethylsilane, (3-phenyl-1-butyne-3-oxy)diphenylmethylsilane, (3-phenyl-1-butyne-3-oxy)dimethylphenylsilane, (3-phenyl-1-butyne-3-oxy)dimethylvinylsilane, (3-phenyl-1-butyne-3-oxy)dimethylhexenylsilane, (cyclohexyl-1-ethyne-1-oxy)dimethylhexenylsilane, (cyclohexyl-1-ethyne-1-oxy)dimethylvinylsilane, (cyclohexyl-1-ethyne-1-oxy)diphenylmethylsilane, (cyclohexyl-1-ethyne-1-oxy)trimethylsilane, and combinations thereof. The silylated acetylenic compounds useful as inhibitors herein can be prepared by methods known in the art, for example, U.S. Pat. No. 6,677,407 to Bilgrien et al. discloses silylation of the above acetylenic alcohols by reaction with chlorosilanes in the presence of an acid acceptor.

[0030] Alternatively, the inhibitor may be an ene-yne ​​compound such as 3-methyl-3-penten-1-yne, 3,5-dimethyl-3-hexen-1-yne, and combinations thereof. Alternatively, the inhibitor may include a triazole, exemplified by benzotriazole. Alternatively, the inhibitor may include a phosphine. Alternatively, the inhibitor may include a mercaptan. Alternatively, the inhibitor may include a hydrazine. Alternatively, the inhibitor may include an amine. The amine is exemplified by tetramethylethylenediamine, 3-dimethylamino-1-propyne, n-methylpropargylamine, propargylamine, 1-ethynylcyclohexylamine, or combinations thereof. Alternatively, the inhibitor may include a fumarate. Fumarates include dialkyl fumarates such as diethyl fumarate, dialkenyl fumarates such as diallyl fumarate, and dialkoxyalkyl fumarates such as bis-(methoxymethyl)ethyl fumarate. Alternatively, the inhibitor may include a maleate. Maleates include dialkyl maleates such as diethyl maleate, dialkenyl maleates such as diallyl maleate, and dialkoxyalkyl maleates such as bis-(methoxymethyl)ethyl maleate. Alternatively, the inhibitor may comprise an ether.

[0031] Alternatively, the inhibitor may include carbon monoxide. Alternatively, the inhibitor may include an alkenyl-functional siloxane oligomer, which may be cyclic or linear, such as methylvinylcyclosiloxane, exemplified by 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane, 1,3-divinyl-1,3-diphenyl-1,3-dimethyldisiloxane, 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, and combinations of two or more thereof. Compounds useful as the inhibitors described above are commercially available, for example, from Sigma-Aldrich Inc. or Gelest, Inc., and suitable inhibitors for use herein are exemplified by those described as Stabilizer E in paragraphs

[0148] to

[0165] of U.S. Patent Application Publication No. 2007 / 0099007.

[0032] Starting material (D) may be a hydrosilylation reaction inhibitor or a combination of two or more of the above hydrosilylation reaction inhibitors. The amount of inhibitor used herein will vary depending on a variety of factors, including the desired reaction rate, the particular inhibitor used, and the selection and amount of each of starting materials (A) and (C). However, when present, the amount of inhibitor may be greater than 0, or alternatively, from 0.02 to 0.8 parts by weight per 100 parts by weight of starting material (A).

[0033] (E)Water The starting material (E) is water, which is generally not limited and may be utilized undiluted (without carrier vehicle / solvent) and / or pure (i.e., without mineral and / or other impurities). For example, the water may be treated or untreated prior to combining with other starting materials in the emulsion. Examples of processes that may be used to purify the water include distillation, filtration, deionization, and combinations of two or more thereof, whereby the water may be deionized, distilled, and / or filtered. Alternatively, the water may be untreated (e.g., tap water, i.e., well water provided by a municipal water system or used without further purification). The water may be utilized in any amount selected by one of skill in the art, depending on various factors, including the desired dilution of the emulsion. However, the amount of water may be 30% to 99%, or 50% to 99%, or 50% to 95%, based on the total weight of all starting materials in the emulsion.

[0034] (F) Buffer system The buffer system (buffer solution) for maintaining the desired pH of the emulsion can be any suitable buffer solution that may contain a monobasic or polybasic acid and its conjugate base. For example, HCO3, which is listed as Agent F in paragraphs

[0145] to

[0147] of U.S. Patent Application Publication No. 2007 / 0099007, can be used. - / CO3 2- and H2PO4 - / HPO4 2- Buffers comprising can be used herein. The buffer may comprise NaCO3 and NaHCO3, and / or citric acid and citrates, such as potassium citrate or sodium citrate. The amount of buffer may be greater than 0, alternatively at least 0.2 parts by weight, alternatively at least 0.4 parts by weight per 100 parts by weight of starting material (A). At the same time, the amount of buffer may be up to 1.6 parts by weight, alternatively up to 1.5 parts by weight, alternatively up to 1.25 parts by weight per 100 parts by weight of starting material (A).

[0035] (G) Reactive olefin surfactants The starting material (G) is an alkenyloxy polyether, which is used to emulsify the silicone release coating composition in water and is also reactive. The alkenyloxy polyether may be substantially linear or linear. The linear alkenyloxy polyether has the formula (GI):

[0036] [ka] wherein D 1 is a divalent hydrocarbon radical of 1 to 30 carbon atoms, and each D 2 are independently selected divalent hydrocarbon radicals of 2 to 10 carbon atoms, where the subscript a is ≧2. Alternatively, the subscript a may be at least 2, alternatively at least 4, alternatively at least 6, alternatively at least 8, alternatively at least 10, while the subscript a may be up to 150, alternatively up to 70, alternatively up to 30, alternatively up to 24, alternatively up to 20, alternatively up to 18, alternatively up to 16. 1 and / or D. 2 The divalent hydrocarbon group may be free of aliphatic unsaturation. 1 (D 1 has 2 or more carbon atoms) and / or D 2 may be linear or branched. 2 Examples of divalent hydrocarbon radicals of the empirical formula -C d H 2d -alkane-diyl groups, where the subscript d is 2 to 10, alternatively 2 to 8, alternatively 2 to 6, alternatively 2 to 4. 1 is the empirical formula -C e H 2e -, where the subscript e is 1 to 30, alternatively 1 to 20, alternatively 1 to 10, alternatively 1 to 4. 1 and / or D. 2 The alkane-diyl group in the formula (I) is a linear alkane-diyl, such as -CH-CH-, -CH-CH-CH-, -CH-CH-CH-CH-, or -CH-CH-CH-CH-CH-CH-CH-, or a branched alkane-diyl, such as

[0037] [ka] Alternatively, each D 2 may be an alkane-diyl group of at least 2, alternatively at least 3, alternatively at least 4 carbon atoms, while at the same time D 2 may be an alkane-diyl group of up to 6, alternatively up to 5, alternatively up to 46 carbon atoms. 2 may have 2, 3, or 4 carbon atoms. Alternatively, each D 1 may have 1 carbon atom. Alternatively, D 1 has 1 carbon atom, D 2 When has two carbon atoms, the alkenyloxy polyether has the formula (G-II):

[0038] [ka] where the index a is as defined above. Alternatively, the index a may be at least 2, alternatively at least 4, alternatively at least 6, alternatively at least 8, alternatively at least 10, while the index a may be up to 30, alternatively up to 24, alternatively up to 20, alternatively up to 18, alternatively up to 16.

[0039] Suitable alkenyloxy polyethers are known in the art and commercially available, such as allyloxy polyoxyethylene having 10 ethylene oxide units per molecule sold under the trade name PLURIOL™ 10R (i.e., Formula G-II, where a=10) or allyloxy polyoxyethylene having 16 ethylene oxide units per molecule sold under the trade name PLURIOL™ 750 R, both from BASF. Other commercially available alkenyloxy polyethers include PLURIOL™ A 300 V, PLURIOL™ A 3090 V, PLURIOL™ A 5890 V, PLURIOL™ A 1190 I, and PLURIOL™ A 700 VP, also available from BASF.

[0040] The amount of (G) alkenyloxy polyether will depend on various factors including whether or not the starting material (H), a polyvinyl alcohol compound, is present, but the amount of (G) alkenyloxy polyether is sufficient to provide a molar ratio of silicon-bonded hydrogen atoms in (B) polyorganohydrogensiloxane to alkenyl groups in (G) alkenyloxy polyether (SiH:alkenyl ratio) of from 2:1 to 25:1, alternatively from 2:1 to 12:1.

[0041] (H) Polyvinyl alcohol The starting material (H) in the emulsion is a polyvinyl alcohol compound. Polyvinyl alcohol compounds are known in the art and are disclosed, for example, in paragraphs

[0172] and

[0173] of US Patent Application Publication No. 2007 / 0099007. The polyvinyl alcohol compound may be made by saponification of polyvinyl acetate, so that up to 65 mol% of the polyvinyl acetate may remain in the polyvinyl alcohol compound used herein. Alternatively, the polyvinyl alcohol compound may be 35 mol% to 99 mol% polyvinyl alcohol (in equilibrium with 65 mol% to 1 mol% polyvinyl acetate). Alternatively, the polyvinyl alcohol compound may be 80% to 98% hydrolyzed. The polyvinyl alcohol compound may have a minimum viscosity of 5 cP in a 4% aqueous solution at 20° C., or a maximum of 200 cSt. Alternatively, the polyvinyl alcohol may have a viscosity of 15 cSt to 55 cSt. The amount of polyvinyl alcohol compound will depend on a variety of factors including the type and amount of (G) alkenyloxy polyether present, but the amount of polyvinyl alcohol compound may be 0 to 10 parts by weight, alternatively 0 to 5 parts by weight, alternatively 0 to 3 parts by weight per 100 parts by weight of starting material (A). Alternatively, the polyvinyl alcohol compound may be present in an amount of 1.5 parts by weight to 10 parts by weight per 100 parts by weight of starting material (A). However, the combined amount of (G) alkenyloxy polyether and (H) polyvinyl alcohol compound may be at least 3.0 parts by weight per 100 parts by weight of starting material (A). Alternatively, when (G) alkenyloxy polyether is present in an amount less than 3 parts by weight per 100 parts by weight of starting material (A), the remainder of (H) polyvinyl alcohol compound is present up to at least 3 parts by weight per 100 parts by weight of starting material (A).

[0042] (I) Biocides Starting material (I) is an optional biocide that can be added to the emulsion. Biocides are known in the art, and for example, biocides are exemplified by (I1) fungicides, (I2) herbicides, (I3) pesticides, (I4) antimicrobials, and combinations of two or more thereof. Exemplary biocides are disclosed, for example, in U.S. Patent No. 9,221,041 to Brandstadt et al. The biocide is optional. However, if used, the biocide may be present in an amount of up to 1.0 part by weight per 100 parts by weight of starting material (A).

[0043] (J) Defoaming agent The emulsion may optionally further comprise starting material (J) anti-foam. The amount of (J) anti-foam may be up to 0.3 parts by weight per 100 parts by weight of starting material (A). Suitable anti-foam agents are exemplified by emulsions containing silica and polydimethylsiloxane. Such anti-foam agents are commercially available from Dow Silicones Corporation (Midland, Michigan, USA), for example, under the trade names DOWSIL™ AFE-1520, DOWSIL™ 7989, SYL-OFF™ EM 7989 ANTIFOAM, XIAMETER™ AFE-0100, XIAMETER™ AFE-1510, XIAMETER™ AFE-1520, or XIAMETER™ AFE-1530.

[0044] (K) Non-functional polyorganosiloxane The emulsion may optionally further comprise a starting material (K), a non-functional polyorganosiloxane. As used herein, "non-functional organopolysiloxane" refers to a polymer having a backbone consisting of alternating silicon and oxygen atoms with organic groups bonded to the other valences of the silicon atoms, such organic groups not undergoing hydrosilylation reactions with the starting materials (A) and (B). Such non-functional organopolysiloxanes are represented by the formula (R 1 3SiO 1 / 2 )2(R 1 2SiO 2 / 2 )c wherein R 1 is as above, and subscript c has a value sufficient to provide a non-functional organopolysiloxane having a viscosity of from 5 cSt to 60,000 cSt as measured according to the test method in Reference Example B below. Examples of non-functional organopolysiloxanes are α,ω-trialkylsiloxy-terminated polydialkylsiloxanes, such as α,ω-trimethylsiloxy-terminated polydimethylsiloxane. Starting material (K) is optional and may be present in an amount of 0 to 15 parts by weight per 100 parts by weight of starting material (A).

[0045] Additional Starting Materials One or more additional starting materials may be added to the emulsions described herein. The one or more additional starting materials may be selected from the group consisting of bactericides (e.g., sorbic acid), colorants (e.g., dyes or pigments), fillers (e.g., silica), and wetting agents (e.g., glycols such as propylene glycol or ethylene glycol). Additional starting materials suitable for use herein are exemplified by the additives described in U.S. Patent Application Publication No. 2007 / 0099007, paragraphs

[0177] to

[0190] , and U.S. Patent Application Publication No. 2002 / 0061365, paragraphs

[0055] to

[0056] .

[0046] Manufacturing method The emulsion can be prepared by combining the starting materials in the amounts described above, in any order, optionally with a masterbatch, and optionally under shear. Alternatively, the emulsion can be formed by subjecting the starting materials to high shear, for example in a rotor and stator type mixer, or in a device that applies increased shear, such as a high pressure homogenizer, microfluidizer, colloid mill, or sonolator (ultrasonic mixer). To avoid premature reactions during the formation of the emulsion, some of the starting materials can be emulsified separately. For example, all or part of starting material (A) can be emulsified in the absence of starting material (B), and then starting material (B) can be added. Alternatively, starting materials (A), (B), and (G) can be emulsified in the absence of a catalyst, which is emulsified and added separately.

[0047] Alternatively, the emulsion may be provided in the form of a kit, for example having two or more separate parts that can be mixed together to form the emulsion. The kit may inhibit the hydrosilylation reaction of the starting materials (A), (B), and (G) prior to use of the emulsion (e.g., prior to coating the emulsion on the surface of a substrate). Typically, this is accomplished by storing the (B) polyorganohydrogensiloxane in a separate portion from the (C) hydrosilylation reaction catalyst. The kit for preparing the release coating emulsion may include: (I) a base emulsion comprising (A) an aliphatically unsaturated polyorganosiloxane, (B) a polyorganohydrogensiloxane, (D) an inhibitor, (E) water, (F) a buffer solution, (G) an alkenyloxy polyether, and, if present, one or more of (H) a polyvinyl alcohol compound, (I) a biocide, and (K) a non-functional polyorganosiloxane; (II) a curing agent emulsion comprising (A) an aliphatically unsaturated polyorganosiloxane, (C) a catalyst for a hydrosilylation reaction, (G) an alkenyloxy polyether, (E) water, and (F) a buffer solution; and optionally, (III)(J) an antifoaming agent. The base emulsion and hardener emulsion (and antifoaming agent, if present) may be combined to form the above emulsion, for example, by mixing at ambient temperature immediately prior to use. The relative amounts of base emulsion and hardener emulsion (weight ratio of base:hardener) may be from 50:1 to 1:1, alternatively from 35:1 to 1:1.

[0048] The emulsion comprises a silicone release coating composition (silicone phase) dispersed in an aqueous phase. The method of preparing the emulsion may optionally further comprise diluting the emulsion to a desired concentration of the silicone phase. The method may optionally further comprise diluting the silicone release coating emulsion with 60 parts by weight to 900 parts by weight of additional water, the additional water being as described above as starting material (E).

[0049] How to use The present invention also provides a process for preparing a coated substrate with the emulsion. The method includes disposing the emulsion on the surface of the substrate. The method further includes heating the coated substrate, i.e., exposing it to an elevated temperature, such as 50°C to 120°C, to remove water (dry) and cure the silicone release coating composition by hydrosilylation reaction of the starting materials (A), (B), and (G), thereby obtaining a coated substrate.

[0050] The emulsion can be placed or distributed on the surface of the substrate in any suitable manner. Typically, the emulsion is applied in wet form by wet coating techniques. In certain embodiments, the emulsion is applied by i) spin coating, ii) brush coating, iii) drop coating, iv) spray coating, v) dip coating, vi) roll coating, vii) flow coating, viii) slot coating, ix) gravure coating, x) size press coating, xi) film press coating, xii) curtain coating, or xiii) any combination of i)-xii). Typically, the emulsion is placed on the substrate, resulting in a wet deposit on the substrate, which is then dried and cured to obtain a coated substrate comprising a cured silicone release coating on the surface of the substrate.

[0051] The substrate is not limited and may be any substrate. The substrate may be subjected to an integrated hot plate or an integrated or stand-alone oven for drying and curing the deposit. The substrate may optionally have continuous or non-continuous shapes, sizes, dimensions, surface roughness, and other characteristics. In certain embodiments, the substrate has a softening point temperature at an elevated temperature.

[0052] The substrate may comprise a plastic, which may be thermosetting and / or thermoplastic. Alternatively, the substrate may comprise a paper, which may be suitable for food contact applications. Specific examples of suitable substrates include polyamide (PA); polyesters, such as polyethylene terephthalate (PET), polybutylene terephthalate (PET), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), liquid crystal polyester; polyolefins, such as polyethylene (PE), polypropylene (PP), polybutylene; styrene resins; polyoxymethylene (POM); polycarbonate (PC); polymethylenemethacrylate (PMMA); polyvinyl chloride (PVC); polyphenylene sulfide (PPS); polyphenylene ether (polyphenylene ether); ether, PPE); polyimide (polyimide, PI); polyamideimide (polyamideimide, PAI); polyetherimide (polyetherimide, PEI); polysulfone (polysulfone, PSU); polyethersulfone; polyketone (polyketone, PK); polyetherketone (PEK); polyvinyl alcohol (polyvinyl alcohol, PVA); polyetheretherketone (polyetheretherketone, PEEK); polyetherketoneketone (polyetherketoneketone, PEKK); polyarylate (polyarylate, PAR); polyethernitrile (polyethernitrile, PEN); celluloses such as triacetyl cellulose, diacetyl cellulose, cellophane, etc.; and papers such as kraft paper.

[0053] The emulsion, or wet deposit, is typically dried and cured at elevated temperature for a period of time. This period is typically sufficient to effect curing, i.e., crosslinking, of the starting materials, including (A), (B), and (G). In certain embodiments, the period is from greater than 0 to 8 hours, alternatively from greater than 0 to 2 hours, alternatively from greater than 0 to 1 hour, alternatively from greater than 0 to 30 minutes, alternatively from greater than 0 to 10 minutes, alternatively from greater than 0 to 2 minutes, alternatively from greater than 0 to 1 minute, alternatively from greater than 0 to 30 seconds. The period of time depends on a variety of factors, including the elevated temperature selected, the desired film thickness, and the amount of water.

[0054] The cure typically has a residence time of 0.5 to 50 seconds, alternatively 1 second to 10 seconds. Residence time, as used herein, refers to the time that the starting materials, including (A), (B), (C) and (G), are subjected to elevated temperatures. Residence time is distinct from cure time, since there may be ongoing cure even after the wet deposit, or a partially cured reaction intermediate thereof, is no longer exposed to the elevated temperatures that typically initiate cure. Alternatively, the coated article may be prepared on a conveyor belt in an oven, and the residence time may be calculated by dividing the length of the oven (e.g., in meters) by the line speed of the conveyor belt (e.g., meters / second).

[0055] This time can be subdivided into iterations of cure, e.g., a first cure and a post cure, e.g., 1 hour for the first cure and 3 hours for the post cure. The elevated temperature can be independently selected in such iterations from any temperature above room temperature and can be the same in each iteration.

[0056] Depending on the thickness and other dimensions of the film and the coating substrate, the coating substrate can be formed through an iterative process. For example, a first deposit can be formed and exposed to a first elevated temperature for a first time to obtain a partially cured deposit. A second deposit can then be placed on the partially cured deposit and exposed to a second elevated temperature for a second time to obtain a second partially cured deposit. This partially cured deposit also further cures while exposed to the second elevated temperature for a second time. A third deposit can be placed on the second partially cured deposit and exposed to a third elevated temperature for a third time to obtain a third partially cured deposit. The second partially cured deposit also further cures while exposed to the second elevated temperature for a second time. This process can be repeated, for example, 1 to 50 times, to build up the coated article as desired. The composite of partially cured layers is typically subjected to a final post-cure, for example, at the elevated temperature and time described above. Each elevated temperature and time may be selected independently and may be the same or different from each other. When the article is formed via an iterative process, each deposit may also be independently selected, and the components and / or their amounts selected in the composition may vary, or even each repeating layer may be fully cured rather than only partially cured in such an iterative process.

[0057] The deposition includes a wet film and the iterative process may be wet-on-wet depending on the curing state of the partially cured layer. Alternatively, the iterative process may be wet-on-dry. The coated substrate, comprising a film formed from the emulsion on the substrate, may have a variety of dimensions, including the relative thickness of the film and the substrate. Once cured, the resulting silicone release coating has a thickness that may vary depending on its end use application. Typically, the silicone release coating may have a thickness of greater than 0 to less than 1 μm, alternatively greater than 0 to 0.9 μm, alternatively greater than 0 to 0.75 μm, alternatively greater than 0 to 0.5 μm, alternatively greater than 0 to 0.25 μm, alternatively greater than 0 to 0.2 μm. However, other thicknesses are contemplated, for example, 0.05 μm to 0.2 μm. For example, the thickness of the film may be 0.1 μm to 10 μm, alternatively 0.15 μm to 5 μm, alternatively 0.2 μm to 2 μm, and alternatively 0.2 μm to 0.6 μm. Alternatively, when the substrate is plastic or the substrate surface having the film is plastic-coated paper containing plastic, the film may have a thickness of 0.05 to less than 1 μm, alternatively 0.05 to 0.9 μm, alternatively 0.05 to 0.8 μm. Alternatively, when the substrate is paper, the film may have a thickness of 0.2 to less than 1 μm, alternatively 0.2 to 0.9 μm, alternatively 0.2 to 0.8 μm, alternatively 0.2 μm to 0.7 μm, alternatively 0.2 μm to 0.6 μm, alternatively 0.2 μm to 0.5 μm, alternatively 0.2 μm to 0.3 μm.

[0058] The coated substrates can be utilized in food contact applications, such as bakery release papers. When the coated substrates are utilized in food contact applications, it is desirable for the silicone release coating to have low extractables, high adhesion to the substrate, and low water absorption. For example, the emulsions described herein may be used in a method for forming bakery papers, the method comprising: (1) On paper substrate, 0.2 to 1.0 g / m2 after curing of silicone release coating 2 coating the emulsion of any one of claims 1 to 10 in an amount sufficient to provide a coating weight of (2) drying the paper substrate; and (3) curing the silicone release coating. EXAMPLES

[0059] These examples are intended to illustrate the invention to one of ordinary skill in the art and should not be construed as limiting the invention as claimed. The starting materials used in these examples are listed in Table 1 below.

[0060] [Table 1]

[0061] DOWSIL™ and SYL-OFF brand starting materials are commercially available from DSC, which stands for Dow Silicones Corporation, Midland, Michigan, USA.

[0062] Reference Example A - Vi / Hexenyl content and SiH content measured by NMR Using NMR spectroscopy, the vinyl and SiH contents of the starting materials in Table 1 were determined as follows: Nuclear magnetic resonance (NMR) spectra were obtained on an NMR BRUKER AVIII (400 MHz) using silicon-free 10 mm tubes and CDCl3 / Cr(AcAc)3 solvent. 29 Chemical shifts for Si-NMR spectra are referenced to the internal solvent resonance and reported relative to tetramethylsilane.

[0063] Reference example B-Dynamic viscosity (cSt) The kinematic viscosities of the starting materials in Table 1 were measured as follows: Dynamic viscosity (DV) was measured using a Brookfield Viscometer DV-I Prime equipped with spindles 2-4 at speeds of 20-100 rpm and a temperature of 25°C.

[0064] In this Reference Example 1, a sample of base emulsion was prepared by combining the starting materials and their amounts as shown in Table 2 below. The amount of each starting material is shown in weight %. The preparation of the base emulsion was done in the laboratory. pH buffered water (containing water, citric acid monohydrate and sodium hydroxide) was first weighed and blended. Polymers (A-1), (B-1) and (K-1) were weighed and blended separately, and surfactants (G) and (H) were added with mixing. Then, buffered water was poured and stirred for 5 minutes. The resulting premix was then emulsified using a High Pressure Sonolator at 100 bar until the target particle size (dv0.9 1 micrometer to 2 micrometer) was reached. The collected amount was blended with (D-1) hydrosilylation inhibitor and biocide package (commercially available and used in the same amount for each base emulsion).

[0065] [Table 2]

[0066] In this Reference Example 2, an emulsion (bath / emulsion) sample was prepared as follows: A base emulsion prepared as in Reference Example 1 was blended with the catalyst emulsion (C-1), water, and an antifoaming agent shown in Table 1. The amounts in parts by weight are shown in Table 3.

[0067] [Table 3]

[0068] In this Reference Example 3, the bakery paper base material is 0.4 g / m 2 The treated surfaces were treated with an emulsion prepared as described in Reference Example 2 having an average silicon coat weight of 100%. Silicon coat weight (CW), immediate extractables, post-cure extractables, water absorption (Cobb), and retention were evaluated as follows:

[0069] Silicon coat weight was measured by X-ray fluorescence using an Oxford lab-x3500 XRF Analyzer after calibration of elemental silicon with sample standards. XRF measurements of blank substrates were performed before triplicate measurements of coated paper samples and reported in g / m 2 The average silicon coat weight or thickness was obtained, expressed as:

[0070] The water resistance of paper substrates was tested by a conventional absorption test known as the Cobb test, e.g. as described in TAPPI 441 om-04 test method. The sample was exposed to water for 45 seconds and the amount of water absorbed after a total of 60 seconds was measured by weight. The "Cobb value" is expressed in g / m 2 The Cobb value represents the mass of absorbed water. The lower the Cobb value, the more water resistant the substrate is. 2 Cobb values ​​of less than 15 g / m are desired by some customers. 2 Cobb values ​​less than 0.01 were desired by other customers.

[0071] The retention test provided a quantification of the rub-off resistance of the silicone release coating retained on the substrate after the abrasion test. The silicon content of the coated substrate was measured by XRF before and after rub-off with the abrasion tester and expressed as the % of Si remaining after rub-off compared to 100% originally coated. The higher the % of Si remaining after rub-off, the better the retention or rub-off resistance.

[0072] The silicone extractables in % of coated paper was measured by its silicone CW before versus after immersion in MIBK (20 min). The solvent dissolves the uncured silicone and the percentage loss is measured. This test was performed immediately after coating the paper and after aging at room temperature for 24 hours and is referred to as immediate extractability ("IM Ext") and post cure extractability ("PC Ext"). The results are reported in Table 4.

[0073] [Table 4]

[0074] Table 4 showed that the comparative silicone release coating emulsions (C1, C2) containing non-reactive Lutensol XP100 produced silicone release coatings with significantly higher levels of immediate extractables compared to the silicone release coating emulsions (1, 2, 3, 4) containing alkenyloxy polyether (reactive surfactant). This indicated that Comparative Examples C1 and C2 had a slower and more incomplete cure than Examples 1, 2, 3, and 4. Examples 1-4 resulted in immediately fully cured silicone release coatings, thus demonstrating that the present invention allows for the rapid manufacturing, cutting, shipping, and loading of newly manufactured silicone-treated bakery paper rolls for distribution.

[0075] Additionally, the adhesion and abrasion resistance of the silicone release coatings prepared in Examples 1-4 were improved over Comparative Examples C1 and C2. Relative to Comparative Examples C1 and C2, Examples 1-3 showed significant improvement, and Example 4 showed improvement even at a relatively low coating weight.

[0076] Water absorption showed a beneficial and significant reduction for Examples 1-3 compared to C1 and C2, and even at a 40% lower coating weight in Example 4, water absorption was reduced compared to C1 and C2. Without being bound by theory, it is believed that this may allow food packaging manufacturers to envision access to new food paper packaging applications such as frozen food packaging, steam cooking, and oven or microwave paper pouch cooking using coated papers prepared with the silicone release coating emulsions of the present invention.

[0077] Anti-adhesion performance (lower is better) as measured by bake residue test is also improved even at lower coating weights with the silicone release coating emulsions containing alkenyloxy polyethers of each of Examples 1-4 compared to the comparative coating emulsions containing the non-reactive surfactants of C1 and C2, facilitating improved recyclability and compostability as well as thinner coating weights for lower cost and improved production.

[0078] Industrial Applicability Problem to be solved: The use of silicone release coating emulsions to coat paper substrates for food contact applications, such as bakery paper, with release performance and water resistance is desirable as an attractive alternative to the health concerns associated with fluorinated and chromium-containing materials for the same applications.However, paper machine in-line runnability issues such as dust formation have been a major difficulty for the use of silicone emulsions.

[0079] Solution: The silicone release coating emulsions described herein can be used to prepare silicone release coatings on paper substrates suitable for food contact applications. The silicone release coating emulsions can be applied to a paper substrate and allowed to dry and cure to form a silicone release coating thereon (as shown in the examples above, the retention test method described above indicates that a high percentage of the silicone release coating remains on the substrate after testing). Additionally, the emulsions described herein can produce silicone release coatings that have other advantages, such as lower extractables (compared to coatings produced with silicone release coating emulsions containing non-reactive surfactants), thereby minimizing the possibility of migration into food. Other advantages are as described above for the data in Table 4.

[0080] Definitions and Use of Terms In this application, all amounts, ratios, and percentages are by weight unless otherwise indicated. The amounts of all starting materials in the emulsion or composition total 100% by weight. The Summary and Abstract are incorporated herein by reference. The articles "a," "an," and "the" each refer to one or more, unless otherwise indicated by the context of the specification. The singular includes the plural unless otherwise indicated. The transitional phrases "comprising," "consisting essentially of," and "consisting of" are used as set forth in Sections §2111.03 I., II., and III of the Manual of Patent Examining Procedure Ninth Edition, Revision 08.2017, Last Revised January 2018. Abbreviations used herein have the definitions in Table 11. The disclosure of a range includes the range itself and any subsumed within the range, as well as the endpoints. Further, for example, disclosure of a range of 15 to 400 includes the subsets of 15 to 137, 138 to 265, and 266 to 400, as well as any other subset subsumed within that range. Similarly, disclosure of a Markush group includes the group as a whole, as well as any individual members and subgroups subsumed therein.For example, the Markush group (i) α,ω-dimethylhydrogensiloxy terminated poly(dimethylsiloxane / methylhydrogensiloxane), (ii) α,ω-dimethylhydrogensiloxy terminated polymethylhydrogensiloxane, (iii) α,ω-trimethylsiloxy terminated poly(dimethylsiloxane / methylhydrogensiloxane), (iv) α,ω-trimethylsiloxy terminated polymethylhydrogensiloxane, (v) α-dimethylhydrogensiloxy-ω-trimethylsiloxy terminated poly(dimethylsiloxane / methylhydrogensiloxane), (vi) Disclosure of α,ω-trimethylsiloxy-α,ω-trimethylsiloxy-terminated polymethylhydrogensiloxane, and (vii) combinations of two or more thereof includes individually the member (iii) α,ω-trimethylsiloxy-terminated poly(dimethylsiloxane / methylhydrogensiloxane); the subgroup (iii) α,ω-trimethylsiloxy-terminated poly(dimethylsiloxane / methylhydrogensiloxane) and (iv) α,ω-trimethylsiloxy-terminated polymethylhydrogensiloxane, and any other individual members and subgroups subsumed therein.

[0081] The following abbreviations used in this application have the definitions set out in Table 7 below.

[0082] [Table 5]

[0083] EMBODIMENTS OF THE PRESENT DISCLOSURE In a first embodiment, a bakery paper suitable for food contact applications comprises a substrate comprising paper and a silicone release coating coated on a surface of the substrate, the silicone release coating comprising: (1) applying a silicone release coating emulsion onto a surface of a substrate, the silicone release coating emulsion comprising: (A) Unit formula (R 1 3SiO 1 / 2 ) i (R 1 2R3 SiO 1 / 2 ) f (R 1 2SiO 2 / 2 ) g (R 1 R 3 SiO 2 / 2 ) h (SiO 4 / 2 ) j In an aliphatic unsaturated polyorganosiloxane of the formula: 1 are independently selected alkyl groups, and each R 3 are independently selected alkenyl groups, and the subscripts i, f, g, h, and j represent the average number of each siloxane unit per molecule, and the subscripts i, f, g, h, and j have values ​​such that 0≦i≦4, f is 0 to 4, 0≦g≦1400, 0≦h≦200, and j is 0 or 1, with the proviso that when the amount (i+f)=2 to 4, the amount (f+h)≧2, and the amount (i+f+g+h) is 15 to 1400; (B) a polyorganohydrogensiloxane in an amount sufficient to provide a molar ratio of silicon-bonded hydrogen atoms in the polyorganohydrogensiloxane (B) to silicon-bonded alkenyl groups in the aliphatic unsaturated polyorganosiloxane (A) (SiH:SiVi ratio) of 1.2:1 to 3.0:1; (C) a hydrosilylation catalyst in an amount sufficient to provide from 10 ppm to 1000 ppm of platinum group metal based on the combined amount of (A) the aliphatically unsaturated polyorganosiloxane and (B) the polyorganohydrogensiloxane; and (D) a hydrosilylation reaction inhibitor, the hydrosilylation reaction inhibitor being present in an amount of 0.02 parts by weight to 0.8 parts by weight per 100 parts by weight of (A) the aliphatic unsaturated polyorganosiloxane; (E) water; (F) a buffer solution, the buffer solution being 0.4 parts by weight to 1.6 parts by weight per 100 parts by weight of the (A) aliphatic unsaturated polyorganosiloxane; an alkenyloxy polyether (G) which is 0.05 parts by weight to 10 parts by weight per 100 parts by weight of the aliphatic unsaturated polyorganosiloxane (A), and the amounts of the polyorganohydrogensiloxane (B) and the alkenyloxy polyether (G) are sufficient to provide a molar ratio of silicon-bonded hydrogen atoms in the polyorganohydrogensiloxane (B) to alkenyl groups in the alkenyloxy polyether (G) (SiH:alkenyl ratio) of 2:1 to 25:1; (H) a polyvinyl alcohol compound, comprising 0 to 10 parts by weight of a polyvinyl alcohol compound per 100 parts by weight of (A) an aliphatic unsaturated polyorganosiloxane; Optionally, (I) a biocide; and (J) a defoaming agent, comprising 0 to 0.3 parts by weight of the defoaming agent per 100 parts by weight of the (A) aliphatic unsaturated polyorganosiloxane; (K) Unit formula (R 1 3SiO 1 / 2 )2(R 1 2SiO 2 / 2 ) c (A) is a non-functional polyorganosiloxane having a functional group of 0 to 15 parts by weight per 100 parts by weight of the aliphatic unsaturated polyorganosiloxane, wherein R 1 is as defined above, and the subscript c has a value sufficient to impart to the non-functional polyorganosiloxane a viscosity of 5 to 60,000 cSt when tested at 25° C. by a rotational viscometer, and a viscosity of 0.2 to 1.0 g / m after cure. 2 a non-functional polyorganosiloxane in an amount sufficient to provide a coating weight of about 100% to form a silicone release coating; (2) drying the substrate; and (3) curing the silicone release coating.

[0084] In a second embodiment, in the method of the first embodiment, the (A) aliphatically unsaturated polyorganosiloxane is represented by the unit formula (R 1 2R 3 SiO 1 / 2 )2(R 1 2SiO2 / 2 ) g wherein each R 1 is methyl, and each R 3 is vinyl and the subscript g is 15 to 1200.

[0085] In a third embodiment, in the method of the first embodiment or the second embodiment, the (B) polyorganohydrogensiloxane is represented by the unit formula (R 1 3SiO 1 / 2 )2(R 1 HSiO 2 / 2 ) z wherein R 1 is methyl and 3≦z≦250.

[0086] In a fourth embodiment, in the method of any one of the first to third embodiments, the polyvinyl alcohol compound is present in an amount of 2.5 parts by weight to 10 parts by weight per 100 parts by weight of starting material (A), and the polyvinyl alcohol compound has a viscosity of 5 cSt to 200 cSt.

[0087] In a fifth embodiment, in the method of any one of the first to fourth embodiments, the alkenyloxy polyether is linear.

[0088] In a sixth embodiment, in the method according to any one of the first to fifth embodiments, the alkenyloxy polyether has the formula:

[0089] [ka] where the subscript a is 10-16.

[0090] In a seventh embodiment, in the method of the sixth embodiment, the amounts of (B) polyorganohydrogensiloxane and (G) alkenyloxy polyether are sufficient to provide a SiH:alkenyl ratio of from 2:1 to 12:1.

Claims

1. 1. A silicone release coating emulsion comprising: (A) Unit formula (R １ ３ SiO １／２ ) ｉ (R １ ２ R ３ SiO １／２ ) ｆ (R １ ２ SiO ２／２ ) ｇ (R １ R ３ SiO ２／２ ) ｈ (SiO ４／２ ) ｊ In an aliphatically unsaturated polyorganosiloxane of the formula: １ is an independently selected alkyl group, and each R ３ are independently selected alkenyl groups, and the subscripts i, f, g, h, and j represent the average number of each siloxane unit per molecule, with the subscripts i, f, g, h, and j having values ​​such that 0≦i≦4, f is 0 to 4, 0≦g≦1400, 0≦h≦200, and j is 0 or 1, with the proviso that when the amount (i+f)=2 to 4, the amount (f+h)≧2, and the amount (i+f+g+h) is 15 to 1400; (B) a polyorganohydrogensiloxane in an amount sufficient to provide a molar ratio of silicon-bonded hydrogen atoms in the polyorganohydrogensiloxane to silicon-bonded alkenyl groups in the aliphatic unsaturated polyorganosiloxane (A) (SiH:SiVi ratio) of 1.2:1 to 3.0:1; (C) a hydrosilylation catalyst in an amount sufficient to provide from 10 ppm to 1000 ppm of platinum group metal based on the combined amount of (A) the aliphatically unsaturated polyorganosiloxane and (B) the polyorganohydrogensiloxane; and (D) a hydrosilylation reaction inhibitor, comprising: (A) 0.02 parts by weight to 0.8 parts by weight of a hydrosilylation reaction inhibitor per 100 parts by weight of the aliphatic unsaturated polyorganosiloxane; (E) water; (F) a buffer solution, comprising: (A) 0.4 parts by weight to 1.6 parts by weight of a buffer solution per 100 parts by weight of the aliphatically unsaturated polyorganosiloxane; (G) an alkenyloxy polyether, (A) from 0.05 parts by weight to 10 parts by weight per 100 parts by weight of said aliphatically unsaturated polyorganosiloxane, and the amounts of (B) said polyorganohydrogensiloxane and (G) said alkenyloxy polyether are sufficient to provide a molar ratio of silicon-bonded hydrogen atoms in (B) said polyorganohydrogensiloxane to alkenyl groups in (G) said alkenyloxy polyether (SiH:alkenyl ratio) of 2:1 to 25:1; (H) a polyvinyl alcohol compound, comprising: (A) 0 to 10 parts by weight of a polyvinyl alcohol compound per 100 parts by weight of the aliphatic unsaturated polyorganosiloxane; Optionally, (I) a biocide; and (J) a defoaming agent, comprising: (A) 0 to 0.3 parts by weight of the defoaming agent per 100 parts by weight of the aliphatic unsaturated polyorganosiloxane; (K) Unit formula (R １ ３ SiO １／２ ) ２ (R １ ２ SiO ２／２ ) ｃ (A) from 0 to 15 parts by weight per 100 parts by weight of said aliphatically unsaturated polyorganosiloxane, １ wherein the subscript c is as defined above and the subscript c is sufficient to impart to said non-functional polyorganosiloxane a viscosity of from 5 to 60,000 cSt when tested at 25° C. by a rotational viscometer using a Brookfield Viscometer DV-I Prime equipped with spindles 2-4 and measuring at speeds of from 20 to 100 rpm.

2. (A) In the unit formula of the aliphatic unsaturated polyorganosiloxane, i = j = h = 0, and the subscript f = 2, and the aliphatic unsaturated polyorganosiloxane has the unit formula (R １ ２ R ３ SiO １／２ ) ２ (R １ ２ SiO ２／２ ) ｇ wherein each R １ is methyl, and each R ３ 2. The emulsion of claim 1, wherein: is vinyl; and the subscript g is 15 to 1200.

3. (B) The polyorganohydrogensiloxane is represented by the unit formula (R １ ３ SiO １／２ ) ２ (R １ HSiO ２／２ ) ｚ wherein R １ 3. The emulsion of claim 1, wherein z is methyl and 3≦z≦250.

4. 4. The emulsion of claim 1, wherein (C) the hydrosilylation reaction catalyst comprises a complex of an alkenyl-functional polydialkylsiloxane and platinum.

5. 5. The emulsion according to claim 1, wherein the hydrosilylation reaction inhibitor comprises an acetylenic alcohol.

6. (F) The emulsion according to any one of claims 1 to 5, wherein the buffer comprises citric acid and sodium hydroxide.

7. 7. The emulsion of any one of claims 1 to 6, wherein (H) the polyvinyl alcohol compound is present in an amount of 1.5 parts by weight to 10 parts by weight per 100 parts by weight of starting material (A), and the polyvinyl alcohol compound has a viscosity of 5 cSt to 200 cSt measured using a Brookfield Viscometer DV-I Prime equipped with spindle 2-4 at a speed of 20 to 100 rpm and a temperature of 25°C.

8. 8. The emulsion of any one of claims 1 to 7, wherein (K) the polyorganosiloxane is present and comprises an α,ω-trimethylsiloxy-terminated polydimethylsiloxane.

9. (G) the alkenyloxy polyether has the formula: 【Chemistry 1】 9. The emulsion of claim 1, having the formula:

10. 10. The emulsion of claim 9, wherein the amount of (B) said polyorganohydrogensiloxane and (G) said alkenyloxypolyether is sufficient to provide a SiH: / alkenyl ratio of from 2:1 to 12:

1.

11. A kit for preparing a release coating emulsion according to any one of claims 1 to 10, comprising: (I) a base emulsion comprising (A) the aliphatically unsaturated polyorganosiloxane, (B) the polyorganohydrogensiloxane, (D) the inhibitor, (E) water, (F) the buffer, (G) the alkenyloxy polyether, and, if present, one or more of (H) the polyvinyl alcohol, (I) the biocide, and (K) the polyorganosiloxane; (II) a curing agent emulsion comprising (A) the aliphatically unsaturated polyorganosiloxane, (C) the hydrosilylation reaction catalyst, (G) the alkenyloxy polyether, (E) water, (F) the buffer, if present, and one or more of (H) the polyvinyl alcohol compound, (I) the biocide, and (K) the non-functional polyorganosiloxane; and optionally, (III)(J) a third part comprising said antifoam agent.

12. A method of forming the emulsion of any one of claims 1 to 10, comprising the steps of: (1) emulsifying starting materials including (A) the aliphatically unsaturated polyorganosiloxane, (B) the polyorganohydrogensiloxane, (D) the inhibitor, (E) water, (F) the buffer, (G) the alkenyloxy polyether, and, if present, one or more of (H) the polyvinyl alcohol, (I) the biocide, and (K) the polyorganosiloxane, thereby forming a base; (2) combining 1 to 50 parts by weight of a base per part by weight of a curing agent emulsion, the curing agent emulsion including (A) the aliphatically unsaturated polyorganosiloxane, (C) the catalyst for a hydrosilylation reaction, (G) the alkenyloxy polyether, (E) water, and (F) the buffer solution; Optionally, (3)(J) combining said antifoam agent, thereby forming said silicone release coating emulsion; Optionally, (4) diluting the silicone release coating emulsion with 60 to 900 parts by weight of additional water.

13. 13. The process of claim 12, wherein step (2), and, if present, step (3), are carried out at a temperature of less than 50°C.

14. 1. A method of forming a bakery paper, comprising: (1) On a substrate including paper, the silicone release coating has a coating weight of 0.2 to 1.0 g / m2 after curing. ２ applying an amount of the emulsion of any one of claims 1 to 10 sufficient to provide a coating weight of (2) drying the substrate; and (3) curing the silicone release coating.

15. 12. Use of the emulsion according to claim 11 on a substrate comprising plastic.

Images