Curable silicone pressure-sensitive adhesive emulsion and preparation method thereof

Abstract

The present invention provides a method for preparing a curable silicone pressure sensitive adhesive emulsion, the method comprising preparing a dispersion of benzoyl peroxide and a phenoxy functional alcohol, and thereafter combining the dispersion with other starting materials for the emulsion.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] none. Technical Field

[0003] The present invention relates to a curable silicone pressure-sensitive adhesive emulsion and a method for preparing the same. The curable pressure-sensitive adhesive emulsion contains a peroxide initiator and can be cured to form a pressure-sensitive adhesive having good adhesion and leaving no or little residue after removal from a stainless steel substrate after exposure to high temperatures. Background Art

[0004] Silicone pressure-sensitive adhesive emulsions can be cured by platinum-catalyzed addition reactions, peroxide-initiated free radical reactions, or aminosilane-catalyzed condensation reactions. However, platinum-catalyzed systems can be expensive, while aminosilane-catalyzed systems can have unstable adhesion or poor cohesion. For solvent-based PSAs, benzoyl peroxide can be used. However, benzoyl peroxide is a crystalline solid that is difficult to dissolve or disperse in water and is therefore difficult to use in waterborne silicone pressure-sensitive adhesives. Summary of the invention

[0005] The present invention discloses a method for preparing a curable silicone pressure-sensitive adhesive emulsion. The method comprises:

[0006] 1) preparing a dispersion comprising

[0007] A) >0 wt. % to <55 wt. % benzoyl peroxide;

[0008] B) 0% to ≤ 25% by weight of water; and

[0009] C) >20 wt% of a phenoxy-functionalized alcohol selected from the group consisting of 1-phenoxy-2-propanol and 2-phenoxyethan-1-ol; and

[0010] 2) combining the dispersion with a starting material comprising

[0011] D) a dihydroxy-terminated polydiorganosiloxane gum;

[0012] E) polyorganosilicate resin;

[0013] F) alcohol ethoxylate surfactants; and

[0014] G) Additional water. DETAILED DESCRIPTION

[0015] The curable silicone pressure sensitive adhesive emulsion described herein can be prepared using a benzoyl peroxide dispersion comprising A) benzoyl peroxide, optionally B) water, and C) a phenoxy functional alcohol selected from the group consisting of 1-phenoxy-2-propanol and 2-phenoxyethan-1-ol.

[0016] A) Benzoyl peroxide

[0017] The starting material A), benzoyl peroxide, has the formula Benzoyl peroxide is available, for example, under the trade name LUPEROX TM Purchased from Millipore Sigma (St. Louis, Missouri, USA). LUPEROX TM The product may contain 75% to 98% benzoyl peroxide and 2% to 25% B) water. The amount of benzoyl peroxide used to prepare the dispersion is sufficient to provide <55%, alternatively ≤50%, and alternatively ≤38%, based on the weight of the dispersion. At the same time, the concentration of benzoyl peroxide is sufficient to provide ≥15%, alternatively ≥±20%, and alternatively ≥37%, based on the weight of the dispersion. Alternatively, the amount of benzoyl peroxide can be >0% to <55%, alternatively 15% to <55%, alternatively 20% to 50%, and alternatively 37% to 50% benzoyl peroxide solids, based on the weight of the dispersion. The balance of the dispersion may include B) water (which may be introduced with the benzoyl peroxide solids or added separately, or both) and C) a phenoxy-functional alcohol.

[0018] B) Water

[0019] Starting material B) is water. Water is optional and is generally unrestricted, and can be used in a clean form (i.e., without any carrier medium / solvent) and / or a pure form (i.e., without or substantially without minerals and / or other impurities). For example, water may be treated or not treated before being added to the above-mentioned dispersion. Examples of methods that can be used to purify water include distillation, filtration, deionization, and a combination of two or more thereof, so that water can be deionized, distilled, and / or filtered. Alternatively, water can be untreated (e.g., tap water, i.e., provided by a municipal water supply system or well water, and used without further purification). When present, all or a portion of water can be introduced together with benzoyl peroxide solid.

[0020] Water can be used in any amount from 0% to 40% based on the weight of the dispersion, and the exact amount can be selected by those skilled in the art based on various factors, such as the equipment and scale used to prepare the curable silicone pressure-sensitive adhesive emulsion. Alternatively, water can be present in an amount from 2% to 25% based on the weight of the dispersion.

[0021] C) Phenoxy functional alcohol

[0022] The starting substance C) in the dispersion is a phenoxy-functional alcohol selected from the group consisting of 1-phenoxy-2-propanol and 2-phenoxyethan-1-ol.

[0023] 1-Phenoxy-2-propanol has the formula and CAS#770-35-4. 2-Phenoxyethanol-1-ol has the formula and CAS#122-99-6. Both 1-phenoxy-2-propanol and 2-phenoxyethanol are available from, for example, Sigma-Aldrich (St. Louis, Missouri, USA.). The phenoxy-functionalized alcohol can be the balance of the above dispersion, for example, the amount of phenoxy-functionalized alcohol in the dispersion can be >20% to 78% based on the weight of the dispersion; alternatively, the amount of phenoxy-functionalized alcohol can be 25% to 78%, alternatively 25% to 70%, and alternatively 37% to 50% based on the weight of the dispersion.

[0024] The above dispersion comprises starting materials A) and C). Alternatively, the dispersion may comprise starting materials A), B) and C); alternatively the dispersion may consist essentially of starting materials A), B) and C); and alternatively the dispersion may consist of starting materials A), B) and C). Prior to combining the dispersion with any other starting materials used to prepare the curable silicone pressure sensitive adhesive emulsion, the dispersion may be free of polyorganosiloxane components, e.g. silicone oils, such as trimethylsiloxy-terminated polydimethylsiloxane. Without wishing to be bound by theory, it is believed that silicone oils may be detrimental to the activity of benzoyl peroxide.

[0025] The dispersion may be formed in any convenient manner such as by mixing. Starting materials A), B) and C) may be combined in any order, under ambient conditions or with heating using any convenient equipment such as a batch reactor equipped with an agitator or a continuous mixing equipment such as a twin screw extruder.

[0026] To form a curable silicone pressure-sensitive adhesive emulsion, the above benzoyl peroxide dispersion can be combined with a starting material comprising: D) a polydiorganosiloxane gum; E) a polyorganosilicate resin; F) an alcohol ethoxylate surfactant; and G) additional water. The curable silicone pressure-sensitive adhesive emulsion can optionally further comprise one or more of H) a polydiorganosiloxane polymer, I) a solvent, and J) a biocide.

[0027] D) Gum

[0028] The starting material D) in the curable silicone pressure-sensitive adhesive emulsion is a bishydroxy-terminated polydiorganosiloxane gum (gum). The gum may have an Mn of ≥ 300,000 g / mol. The gum may have the following formula: Each R 1 is an independently selected monovalent hydrocarbon group; and the value of subscript a is sufficient to give the gum a number average molecular weight (Mn) of ≥ 300,000 g / mol, alternatively 300,000 g / mol to 1,000,000 g / mol, alternatively 300,000 g / mol to 400,000 g / mol, and alternatively 500,000 g / mol to 800,000 g / mol. The Mn of the gum is measured by GPC according to the techniques described herein.

[0029] In the formula of gum, each R 1 is an independently selected monovalent hydrocarbon group. The monovalent hydrocarbon group may have 1 to 18 carbon atoms. The monovalent hydrocarbon group may not contain aliphatic unsaturated groups. Alternatively, each R 1 R may have from 1 to 12 carbon atoms, and alternatively from 1 to 6 carbon atoms. 1 Examples of suitable monovalent hydrocarbon groups include alkyl groups and aromatic groups, such as aryl groups and aralkyl groups. Examples of alkyl groups include, but are not limited to, methyl, ethyl, propyl (e.g., isopropyl and / or n-propyl), butyl (e.g., isobutyl, n-butyl, tert-butyl and / or sec-butyl), pentyl (e.g., isopentyl, neopentyl and / or tert-pentyl), hexyl, heptyl, octyl, nonyl and decyl, and branched alkyl groups with 6 or more carbon atoms; and cycloalkyl groups, such as cyclopentyl and cyclohexyl. Examples of aryl groups include, but are not limited to, cyclopentadienyl, phenyl, tolyl, xylyl, anthracenyl, benzyl, 1-phenylethyl, 2-phenylethyl and naphthyl. Alternatively, each R 1 Can be independently selected from the group consisting of alkyl and aryl. Alternatively, each R 1 Can be independently selected from methyl and phenyl. Alternatively, each R 1 Alternatively, each R 1 It may be methyl.

[0030] Gums are known in the art and can be prepared by processes such as hydrolysis and condensation of corresponding organohalosilanes or equilibration of cyclic polydiorganosiloxanes. Examples of suitable gums for use in curable silicone pressure sensitive adhesive emulsions are:

[0031] i) dihydroxy-terminated polydimethylsiloxane,

[0032] ii) bishydroxy-terminated poly(dimethylsiloxane / methylphenyl)siloxane,

[0033] iii) bishydroxy-terminated poly(dimethylsiloxane / diphenyl)siloxane,

[0034] iv) phenyl, methyl, hydroxy-siloxy terminated polydimethylsiloxane, and

[0035] v) A combination of two or more of i) to iv). Alternatively, the polydiorganosiloxane gum may be selected from the group consisting of i), ii) and iii). Alternatively, the polydiorganosiloxane gum may be i).

[0036] The amount of gum used in the emulsion depends on various factors, including the molecular weight of the gum selected. However, the gum can be added in an amount sufficient to provide at least 7% gum based on the weight of the emulsion. At the same time, the amount of gum can be up to 30% based on the weight of the emulsion. Alternatively, based on the same basis, the amount of gum can be 7.5% to 25%, alternatively 8% to 22%.

[0037] E) Resin

[0038] The starting material E) in the curable silicone pressure-sensitive adhesive emulsion is a polyorganosilicate resin. The polyorganosilicate resin comprises a M 3SiO 1 / 2 The monofunctional unit ("M" unit) and the formula SiO 4 / 2 A tetrafunctional unit ("Q" unit) wherein each R M is an independently selected monovalent hydrocarbon group. M The monovalent hydrocarbon group of may have 1 to 20 carbon atoms, or 1 to 12 carbon atoms, or 1 to 8 carbon atoms, or 1 to 4 carbon atoms, or 1 to 2 carbon atoms. M The hydrocarbyl group of R may be selected from alkyl groups, alkenyl groups and aryl groups; alternatively alkyl and aryl; alternatively alkyl and alkenyl; and alternatively alkyl. The alkyl groups and aryl groups are as described above for R 1 Alternatively, in the polyorganosilicate resin, each R M Can be independently selected from alkyl, alkenyl and aryl. Alternatively, each R M can be selected from methyl, vinyl and phenyl. Alternatively, at least one third, alternatively at least two thirds of R M The group is a methyl group. Alternatively, examples of M units may include (Me3SiO 1 / 2 )、(Me2PhSiO 1 / 2 ) and (Me2ViSiO 1 / 2The polyorganosilicate resins are soluble in solvents such as those described herein, exemplified by liquid hydrocarbons such as benzene, toluene, xylene, ethylbenzene, heptane, and combinations of two or more thereof; or liquid organosilicon compounds such as low viscosity linear and cyclic polydiorganosiloxanes.

[0039] When prepared, the polyorganosilicate resin comprises the above-mentioned M and Q units, and the polyorganosilicate resin also comprises units having silanol (silicon-bonded hydroxyl) groups and may comprise the formula Si(OSiR M 3)4 neopentamers, where R M As described above. As described in Reference Example 2, column 32, U.S. Pat. No. 9,593,209, Si 29 Nuclear magnetic resonance (NMR) spectroscopy can be used to measure the molar ratio of M and Q units, where the ratio is expressed as {M(resin)+(M(neopentamer)} / {Q(resin)+Q(neopentamer)} and represents the molar ratio of the total number of triorganosiloxy groups (M units) in the resin and neopentamer portions of the polyorganosilicate resin to the total number of silicate groups (Q units) in the resin and neopentamer portions.

[0040] The Mn of a polyorganosilicate resin depends on various factors, including the presence of M The type of hydrocarbon group represented by the polyorganosilicate resin. When the peak representing the neopentamer is excluded from the measurement, the Mn of the polyorganosilicate resin refers to the number average molecular weight measured using GPC according to the procedure in Reference Example 1 of column 31 of U.S. Patent 9,593,209. The Mn of the polyorganosilicate resin may be at least 1,500 g / mol. At the same time, the Mn of the polyorganosilicate may be up to 15,000 g / mol. Alternatively, the Mn of the polyorganosilicate resin may be >3,000 g / mol to 8,000 g / mol. Alternatively, the Mn of the polyorganosilicate resin may be 4,500 g / mol to 7,500 g / mol.

[0041] U.S. Patent 8,580,073, column 3, line 5 to column 4, line 31, is hereby incorporated by reference for the disclosure of silicone resins, which are suitable polyorganosilicate resins for use herein. The polyorganosilicate resins can be prepared by any suitable method such as co-hydrolysis of the corresponding silanes or by a silica hydrosol end-capping method. The polyorganosilicate resins can be prepared by a silica hydrosol end-capping method such as those disclosed in U.S. Patent 2,676,182 to Daudt et al.; U.S. Patent 4,611,042 to Rivers-Farrell et al.; and U.S. Patent 4,774,310 to Butler et al. The above-mentioned method of Daudt et al. involves reacting a silica hydrosol with a hydrolyzable triorganosilane (such as trimethylchlorosilane), a siloxane (such as hexamethyldisiloxane), or a mixture thereof under acidic conditions, and recovering a copolymer having M units and Q units. The resulting copolymer typically contains 2 to 5 weight percent hydroxyl groups.

[0042] The intermediates used to prepare the polyorganosilicate resins may be triorganosilanes and silanes having four hydrolyzable substituents or alkali metal silicates. The triorganosilanes may have the formula R M 3SiX 1 , where R M As mentioned above and X 1 = represents a hydrolyzable substituent. A silane having four hydrolyzable substituents may have the formula SiX 2 4, where each X 2 is halogen, alkoxy or hydroxy. Suitable alkali metal silicates include sodium silicate.

[0043] The polyorganosilicate resins prepared as described above are uncapped and generally contain silicon-bonded hydroxyl groups, i.e., having the formula HOSi 3 / 2 and / or (HO) x R M (3-x) SiO 1 / 2, wherein the subscript x is 1, 2 or 3. The polyorganosilicate resin may contain up to 2% silicon-bonded hydroxyl groups. The concentration of silicon-bonded hydroxyl groups present in the polyorganosilicate resin may be determined using FTIR spectroscopy according to ASTM Standard E-168-16. For certain applications, it may be desirable that the amount of silicon-bonded hydroxyl groups be less than 0.7%, alternatively less than 0.3%, alternatively less than 1%, and alternatively 0.3% to 0.8%. The silicon-bonded hydroxyl groups formed during the preparation of the polyorganosilicate resin may be converted to trihydrocarbylsiloxane groups or to different hydrolyzable groups by a process known as end-capping, such as reacting the polyorganosilicate resin with a silane, disiloxane or disilazane containing an appropriate end group. The silane containing the hydrolyzable group may be added in an excess molar amount of the amount required to react with the silicon-bonded hydroxyl groups on the polyorganosilicate resin to form an end-capped resin.

[0044] One or more polyorganosilicate resins can be combined and used in the curable silicone pressure-sensitive adhesive emulsion. For example, an uncapped resin having a relatively high amount of hydroxyl groups can be used in combination with a capped resin having a lower amount of hydroxyl groups than the uncapped resin. Alternatively, one or more resins used can be capped.

[0045] Thus, the polyorganosilicate resin may comprise (E-1) a capped resin as described above and (E-2) an uncapped resin as described above. The capped resin may have a unit formula: (R M 3SiO 1 / 2 ) z (SiO 4 / 2 ) o X 2 p , where R M and X 2 As described above, and the values ​​of subscripts z and o are such that o>1, and subscript z>4, the value of the amount (o+z) is sufficient to impart the above-described Mn to the end-capped resin (e.g., 1500 g / mol to 5,000 g / mol, alternatively 2,000 g / mol to 5,000 g / mol, alternatively 2,500 g / mol to 4,900 g / mol, and alternatively 2,500 g / mol to 4,700 g / mol, and alternatively 2,900 g / mol to 4,700 g / mol), and the value of subscript p is sufficient to impart the above-described hydrolyzable group content to the end-capped resin (e.g., 0% to <2%, alternatively 0% to 1.5%, and alternatively 0% to 1.0%). The starting material (E-2) uncapped resin may have a unit formula (R M 3SiO 1 / 2 ) z’ (SiO 4 / 2 ) o’ X 2p’ , where R M and X 2 As described above, and the values ​​of subscripts z' and o' are such that o'>1, and subscript z'>4, the value of the amount (o'+z') is sufficient to impart the above-described Mn to the capped resin (e.g., 1,500 g / mol to 5,000 g / mol, alternatively 2,000 g / mol to 5,000 g / mol, alternatively 2,500 g / mol to 4,900 g / mol, and alternatively 2,500 g / mol to 4,700 g / mol, and alternatively 2,700 g / mol to 4,700 g / mol), and the value of subscript p' is sufficient to impart the above-described hydrolyzable group content to the uncapped resin (e.g., ≥2% to 10%).

[0046] The amount of polyorganosilicate resin may be sufficient to provide a weight ratio of starting material D) / starting material E) (and starting material H when present). This is referred to as the [resin / (gum+polymer)] ratio, which may have a value of 0.2 to 2.0, alternatively 0.5 to 2.0. Alternatively, the amount of E) polyorganosilicate resin may be at least 20%, alternatively ≥ 24%, based on the weight of the curable silicone pressure-sensitive adhesive emulsion. At the same time, the amount may be sufficient to provide up to 30%, alternatively ≤ 27%, of polyorganosilicate resin based on the same basis.

[0047] F) Surfactants

[0048] The starting material F) in the curable silicone pressure-sensitive adhesive emulsion is an alcohol ethoxylate surfactant. The alcohol ethoxylate surfactant may be present in an amount of ≥5% based on the combined weight of all starting materials in the curable silicone pressure-sensitive adhesive emulsion. At the same time, the alcohol ethoxylate surfactant may be present in an amount of ≤±10% based on the combined weight of all starting materials in the curable silicone pressure-sensitive adhesive emulsion. Alternatively, the alcohol ethoxylate surfactant may be present in an amount of 5% to 7% based on the combined weight of all starting materials in the curable silicone pressure-sensitive adhesive emulsion.

[0049] The alcohol ethoxylate surfactant may be a polyether-modified polyorganosilicate (MQ) resin. Such resins may comprise a E 3SiO 1 / 2 The M unit and formula SiO 4 / 2 Q unit, where each R E independently selected from polyether groups and alkyl groups of 1 to 20 carbon atoms, such as those described above for R MThe alkyl group is described. Polyether-modified MQ resins are known and disclosed, for example, in PCT Publication WO 2015 / 196400 A1. Polyether-modified MQ resins can be prepared, for example, by capping the above-mentioned polyorganosilicate resin as starting material E) with polyether functional groups, as described in U.S. Pat. No. 9,732,191.

[0050] Alternatively, the alcohol ethoxylate surfactant may be an organic alcohol ethoxylate, which is nonionic. Examples include 2-ethylhexanol ethylene oxide propylene oxide, which is available under the trade name ECOSURF TM EH-6 is available from Dow Chemical Company. Alternatively, the alcohol ethoxylate surfactant comprises α-[3,5-dimethyl-1-(2-methylpropyl)hexyl]-ωhydroxy-poly(oxy-1,2-ethanediyl). The organic alcohol ethoxylate surfactant may be a mixture comprising water (up to 10%), an alcohol ethoxylate such as α-[3,5-dimethyl-1-(2-methylpropyl)hexyl]-ωhydroxy-poly(oxy-1,2-ethanediyl) (at least 87%), and poly(ethylene oxide) (up to 3%). The mixture may be TERGITOL TM TMN-6 is commercially available from Dow Chemical Company.

[0051] G) Additional water

[0052] Starting material G) is additional water, which may be as described above for starting material B). The amount of additional water may be added in one or more aliquots. When more than one aliquot is added, mixing may be performed between each addition. The total amount of water added may be sufficient to provide at least 20%, alternatively ≥24% water to the curable silicone pressure-sensitive adhesive emulsion, based on the weight of the emulsion. At the same time, the total amount of water added may be up to 40%, alternatively ≤35%. Alternatively, the total amount of water (B and G) in the emulsion may be >20% to <40%, alternatively 24% to 36%, based on the weight of the curable silicone pressure-sensitive adhesive.

[0053] H) Polymer

[0054] In addition to D) the gum, the curable silicone pressure-sensitive adhesive emulsion may optionally further comprise H) a bishydroxy-terminated polydiorganosiloxane polymer (polymer). The polymer may have the following formula:

[0055] Where R 1As described above and subscript b < subscript a. The value of subscript b is sufficient to impart a viscosity of ≤ 200,000 cst to the polymer, as measured as described below in Reference Example 15. Alternatively, the value of subscript b is sufficient to impart a viscosity of 10,000 cst to 100,000 cst, alternatively 20,000 cst to 95,000 cst, alternatively 30,000 cst to 90,000 cst, alternatively 40,000 cst to 85,000 cst, and alternatively 50,000 cst to 80,000 cst to the polymer.

[0056] Polymers suitable for use as starting materials H) are known in the art and can be prepared by processes such as hydrolysis and condensation of the corresponding organohalosilanes or equilibration of cyclic polydiorganosiloxanes. Examples of suitable polymers for use as starting materials H) are:

[0057] i) dihydroxy-terminated polydimethylsiloxane,

[0058] ii) bishydroxy-terminated poly(dimethylsiloxane / methylphenylsiloxane),

[0059] iii) bishydroxy-terminated poly(dimethylsiloxane / diphenylsiloxane),

[0060] iv) phenyl, methyl, hydroxy-siloxy terminated polydimethylsiloxane,

[0061] v) a combination of two or more of i) to iv). Alternatively, the starting material H) may be selected from the group consisting of i), ii) and iii). Alternatively, the starting material H) may be i).

[0062] The amount of the starting material H) can be 0 to 20%, alternatively 0 to <13%, based on the weight of the curable silicone pressure-sensitive adhesive emulsion. Alternatively, when used, the starting material H) can be added in an amount of 10% to 15%, alternatively 11% to 13%, based on the weight of the curable silicone pressure-sensitive adhesive emulsion.

[0063] I) Solvent

[0064] Starting material I) is an optional solvent. The solvent may be added during the preparation of the emulsion, for example to help mix and deliver one or more starting materials. For example, D) gum and / or E) resin may be dissolved in a solvent before being combined with other starting materials to prepare a curable silicone pressure-sensitive adhesive emulsion. The solvent may be an organic solvent, such as a hydrocarbon, a ketone, an acetate, an ether. Suitable hydrocarbons for the solvent may be aromatic hydrocarbons, such as ethylbenzene, benzene, toluene or xylene; aliphatic hydrocarbons, such as hexane, heptane, octane or isoparaffin; or a combination thereof. Alternatively, the solvent may be a glycol ether, such as propylene glycol methyl ether, dipropylene glycol methyl ether, propylene glycol n-butyl ether. Suitable ketones include acetone, methyl ethyl ketone or methyl isobutyl ketone. Suitable acetates include ethyl acetate or isobutyl acetate. Suitable ethers include diisopropyl ether or 1,4-dioxolane. Alternatively, the solvent may be selected from the group consisting of toluene, xylene, heptane, ethylbenzene and a combination of two or more thereof.

[0065] The amount of solvent will depend on a variety of factors, including the type of solvent selected and the amount and type of other starting materials. However, based on the combined weight of all starting materials in the emulsion, the amount of solvent can be 0% to 20%, alternatively 0% to 15%, alternatively 0% to 10%, alternatively 5% to 15%, and alternatively 5% to 10%. All or a portion of the solvent can be added together with one or more of the other starting materials. For example, the polyorganosilicate resin and / or the catalyst can be dissolved in the solvent before combining with the other starting materials in the curable silicone pressure-sensitive adhesive emulsion. After the starting materials for the oil phase of the emulsion are combined and before the starting materials that form the aqueous phase are combined, all or a portion of the solvent can be optionally removed.

[0066] J) Biocides

[0067] The starting material J) is a biocide which may be optionally added to the curable silicone pressure-sensitive adhesive emulsion. Biocides are known in the art and are commercially available. For example, the biocide may be a preservative such as BIOBAN TM Products or KATHON TM A product which is an aqueous preservative comprising 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one. Alternatively, the biocide may include an algaecide such as KLARIX TM Algaecides, such as BIOBAN TM 、KATHON TM 、KLARIX TMand other biocides are commercially available from Dow Chemical Company, Midland, Michigan, USA. The biocide may be added in an amount of 0% to 5%, alternatively 0.1% to 5%, based on the weight of the curable silicone pressure sensitive adhesive emulsion.

[0068] Method for preparing emulsion

[0069] The method for preparing the above-mentioned curable silicone pressure-sensitive adhesive emulsion comprises:

[0070] 1) preparing the above dispersion, which comprises

[0071] A) >0 wt. % to <55 wt. % benzoyl peroxide;

[0072] B) 0% to ≤ 25% by weight of water; and

[0073] C) >20 wt% of a phenoxy-functionalized alcohol selected from the group consisting of 1-phenoxy-2-propanol and 2-phenoxyethan-1-ol; and

[0074] 2) combining the dispersion with a starting material comprising

[0075] D) polydiorganosiloxane gum;

[0076] E) polyorganosilicate resin;

[0077] F) alcohol ethoxylate surfactant;

[0078] G) Additional water.

[0079] Optionally H) polydiorganosiloxane gum

[0080] Optionally 1) solvent

[0081] optionally J) a biocide; thereby forming an emulsion.

[0082] The curable silicone pressure-sensitive adhesive emulsion prepared by the method described herein is an oil-in-water (o / w) emulsion, that is, the emulsion comprises an oil phase dispersed in an aqueous phase. The oil phase will comprise starting materials containing D), E) and F) and, when present, H) and I). Two or more of the starting materials D), E), F), H) and I) may be combined with each other in any order before, during or after the preparation of the dispersion in step 1) and before the dispersion prepared in step 1) is combined with the starting materials in step 2).

[0083] For example, starting material D), E), F), H) and I) can be combined by mixing in any order and by any convenient way for mixing high viscosity materials. Mixing to form a uniform mixture is also referred to as homogenization. The method for combining starting materials can occur simultaneously or can be carried out in a multi-step process. For example, starting material D), E) and H) and I) (when present) can be combined, and subsequently mixed via any of the following techniques. Alternatively, starting material D) and / or E) can first be combined and mixed with I) solvent, and then in step 2) before the resulting solution is mixed with one or more other starting materials. Alternatively, starting material G) can be combined with starting material D), E) and F) and when present H) and / or I), and before adding the dispersion from step 1), emulsify the resulting mixture. Those skilled in the art will be able to select the starting material D), E), F), G), H) and I) parts for combination and mixing, depending on the selection of amount used and the specific mixing technique for combining the starting material comprising the emulsion oil phase.

[0084] In step 2), the dispersion prepared in step 1) is combined with the remaining starting materials under conditions that emulsify the starting materials. Starting materials G) Additional water may be added in one or more aliquots before and / or during step 2), and when more than one aliquot is used, the method may include mixing between additions.

[0085] Preparation of the dispersion in step 1) and combination of the dispersion and the starting material before and during step 2) can be carried out by mixing in an intermittent, semi-batch or continuous process. Mixing can be carried out, for example, using the following equipment: intermittent mixing equipment with medium / low shear, such as a can mixer, a double planetary mixer, a conical screw mixer, a ribbon blender, a double arm or a bow knife mixer. Alternatively, intermittent equipment with high shear and / or high-speed dispersers can be used in step 1) and / or step 2), and these devices include equipment such as those manufactured by Charles Ross & Sons, NY and Hockmeyer Equipment Corp., NJ; such as those manufactured under the trade name Speedmixer TMand intermittent mixing devices with high shear, including Banbury type (CW Brabender Instruments Inc., NJ) and Henschel type (Henschel mixers America, TX). Illustrative examples of continuous mixers / compounders include: single screw extruders, twin screw extruders and multi-screw extruders, co-rotating extruders, such as those manufactured by Krupp Werner & Pfleiderer Corp, Ramsey, NJ and Leistritz, NJ; extruders such as twin screw counter-rotating extruders, two-stage extruders, twin rotor continuous mixers, dynamic or static mixers, or combinations of these devices.

[0086] The method may optionally further comprise devolatilizing the curable silicone pressure sensitive adhesive emulsion. Devolatilization may be performed by any convenient means, such as heating the emulsion under vacuum. Devolatilization may be performed during water addition or before the last aliquot of water is added to compensate for any water that may be removed during devolatilization. Devolatilization may be performed, for example, with a devolatilization extruder.

[0087] How to use

[0088] The curable silicone pressure-sensitive adhesive emulsion prepared as described above can be used to form an adhesive article, such as a silicone pressure-sensitive adhesive prepared by coating the curable silicone pressure-sensitive adhesive emulsion on a substrate and curing it.

[0089] The curable silicone pressure-sensitive adhesive emulsion can be applied to the substrate by any convenient means. For example, the curable silicone pressure-sensitive adhesive emulsion can be applied to the substrate by a grooved roll coater, a notched wheel coater, a rubber roll coater, a rubber roll-groove roll coater, a roll coater, a reverse roll coater, an air knife coater, or a curtain coater.

[0090] Substrate can be any material that can withstand the curing conditions (described below) for curing the pressure-sensitive adhesive composition to form a pressure-sensitive adhesive on a substrate. For example, any substrate that can withstand heat treatment at a temperature equal to or greater than 180°C, alternatively 150°C is suitable. Examples of materials suitable for such substrates include polymer films such as polyimide (PI), polyetheretherketone (PEEK), polyethylene naphthalate (PEN), liquid crystal polyarylate, polyamideimide (PAI), polyether sulfide (PES), polyethylene terephthalate (PET), polycarbonate (PC), thermoplastic polyurethane (TPU), polyethylene (PE) or polypropylene (PP). Alternatively, the substrate can be glass. The thickness of the substrate is not critical, however, the thickness can be 5 μm to 300 μm, or 50 μm to 250 μm, or 100 μm to 300 μm, or 100 μm and or 50 μm. Alternatively, the substrate may be selected from the group consisting of PET, TPU, PC and glass. Alternatively, the substrate may be a polymer substrate, such as PET.

[0091] Adhesive articles (such as films or tapes) can be prepared by applying a curable silicone pressure-sensitive adhesive emulsion to a substrate and curing, as described above. The method for preparing an adhesive article may also include removing all or part of the water before and / or during curing. Removing the water solvent can be carried out by any convenient means, such as heating at a temperature that evaporates the water without completely curing, for example, heating at a temperature of 70°C to 90°C, alternatively 50°C to <100°C, and alternatively 70°C to 80°C for a time sufficient to remove all or part of the water (e.g., 30 seconds to 1 hour, alternatively 1 minute to 5 minutes).

[0092] Curing can be carried out by heating at a temperature of 80°C to 200°C, alternatively 90°C to 180°C, alternatively 100°C to 180°C, alternatively 110°C to 180°C for a time sufficient for curing (e.g., 30 seconds to one hour, alternatively 1 minute to 5 minutes). Curing can be carried out by placing the substrate in an oven. The amount of curable silicone pressure-sensitive adhesive emulsion to be applied to the substrate depends on the specific application, however, the amount can be sufficient to make the thickness of the pressure-sensitive adhesive after curing can be 5μm to 100μm, and for the protective film, the thickness can be 5μm to 50μm, alternatively 10μm to 40μm, and alternatively 15μm to 40μm.

[0093] The methods described herein may also optionally include applying a removable release liner to the silicone pressure sensitive adhesive opposite the substrate, for example to protect the silicone pressure sensitive adhesive prior to use of the adhesive article. The adhesive article may be a protective film for use in a display device. Alternatively, the adhesive article may be an industrial tape. Alternatively, the silicone pressure sensitive adhesive may be used in healthcare or personal care applications.

[0094] Example

[0095] The starting materials used in the following exemplary embodiments are described in Table 1.

[0096] Table 1 - Starting materials

[0097]

[0098] In this Reference Example 1, Emulsion 1 was prepared as follows. 8.5 parts of Gum 1 and 12.6 parts of Polymer 1 were mixed with 16.4 parts of Solvent-based Unblocked Resin 1 and 23.1 parts of Solvent-based Blocked Resin 1. The resulting mixture was mixed with 6 parts of OCS to obtain a uniform mixture. Then, 6 parts of

[0099] Water to form a thick O / W (oil in water) phase. 27.4 parts of water were added to dilute the phase to obtain Emulsion 1. The average particle size of Emulsion 1 was 0.3um-0.4um.

[0100] In this Reference Example 2, Emulsion 2 was prepared as follows. 21.1 parts of gum 1 were mixed with 16.4 parts of solvent-based unblocked resin 1 and 23.1 parts of solvent-based blocked resin 1. The resulting mixture was mixed with 6 parts of OCS to obtain a uniform mixture. Then 6 parts of water were added under high shear to form a thick O / W (oil in water) phase. 27.4 parts of water were added to dilute the phase and form Emulsion 2. The average particle size of Emulsion 2 was 1.5 um.

[0101] In this Reference Example 3, Emulsion 3 was prepared as follows. 21.1 parts of gum 1 were mixed with 42.1 parts of solvent-based end-capping resin 2. The resulting mixture was mixed with 6.4 parts of OCS to obtain a uniform mixture. Then 6.4 parts of water were added under high shear to form a thick O / W (oil in water) phase. 24 parts of water were added to dilute the phase to obtain Emulsion 3. The average particle size of Emulsion 3 was 1.3 um.

[0102] In this Reference Example 4, Emulsion 4 was prepared as follows. 21.1 parts of gum 1 were mixed with 17.7 parts of solvent-based unblocked resin 2 and 23.1 parts of solvent-based blocked resin 1. The resulting mixture was mixed with 6.2 parts of OCS to form a uniform mixture. Then 6.2 parts of water were added under high shear to form a thick O / W (oil in water) phase. 25.7 parts of water were added to dilute the phase to obtain Emulsion 4. The average particle size of Emulsion 4 was 1.5 um.

[0103] In this Reference Example 5, Emulsion 5 was prepared as follows. 21.1 parts of Gum 1 was mixed with 37.8 parts of Solvent-Based Capping Resin 1. The resulting mixture was mixed with 6 parts of OCS to obtain a uniform mixture. Then 6 parts of water were added under high shear to form a thick O / W (oil in water) phase. 29.1 parts of water were added to dilute the phase to obtain Emulsion 5. The average particle size of Emulsion 5 was 1.7 um.

[0104] In this Reference Example 6, Emulsion 6 was prepared as follows. 8.5 parts of gum 1 and 12.6 parts of polymer 1 were mixed with 16.4 parts of solvent-based unblocked resin 1 and 23.1 parts of solvent-based blocked resin 1. The resulting mixture was mixed with 6 parts of organic surfactant 1 to obtain a uniform mixture. Then 6 parts of water were added under high shear to form a thick O / W (oil in water) phase. 27.4 parts of water were added to dilute the phase to obtain Emulsion 6. The average particle size of Emulsion 6 was 0.2um-0.3um.

[0105] In this Reference Example 7, Emulsion 7 was prepared as follows. 8.5 parts of gum 1 and 12.6 parts of polymer 1 were mixed with 16.4 parts of solvent-based unblocked resin 1 and 23.1 parts of solvent-based blocked resin 1. The resulting mixture was mixed with 6 parts of organic surfactant 2 to obtain a uniform mixture. Then 6 parts of water were added under high shear to form a thick O / W (oil in water) phase. 27.4 parts of water were added to dilute the phase to obtain Emulsion 7. The average particle size of Emulsion 7 was 0.35 um.

[0106] In this Reference Example 8, BPO dispersion samples were prepared as follows: Catalyst 1 was added to Dispersion 1 or Dispersion 2, followed by mixing for 30 minutes. The BPO dispersion samples are summarized in the following Table 2. Amounts are expressed in parts by weight.

[0107] Table 2 - BPO dispersion samples

[0108] Dispersion I II III IV V Catalyst 1 50 50 50 50 50 Dispersion 1 50 25 18 137.5 0 Dispersion 2 0 0 0 0 50 Benzoyl peroxide content (weight %) 37.5 50 55 20 37.5

[0109] Dispersion III formed a paste that was too dry to be added to any of the emulsions 1-7 prepared as described above.

[0110] In this Example 8, 50 parts by weight of Emulsion 1 and 1.21 parts by weight of Catalyst 1 were mixed under high shear for 15 minutes. The resulting mixture was coated on a 50 um thick PET film and cured at 80°C for 2 minutes and at 180°C for 5 minutes. The resulting film had poor appearance and cohesion, and there was a large amount of residue on the steel plate after the cold peel test. The amount of each starting material and the results are summarized in Table 3 below.

[0111] In this Example 9, 50 parts by weight of Emulsion 1 was mixed with 0.61 parts by weight of aminoethylaminopropyltrimethoxysilane (curing agent 1) to form Sample 9. The mixture was coated on a PET film having a thickness of 50 um and cured at 150°C for 5 minutes. For a dry coating thickness of 25 um-30 um, the 180° peel adhesion was 500 g / inch, and for a 200°C cold peel, the heat resistance was unqualified. In addition, the film appearance was poor. The amount of each starting material and the results are summarized in Table 3 below.

[0112] In this Example 10, 50 parts by weight of Emulsion 1 was mixed with 1.82 BPO paste (Catalyst 2) from AkzoNobel to form Sample 10. Sample 10 was coated on a PET film having a thickness of 50 um and cured at 80°C for 2 minutes and at 180°C for 5 minutes. Sample 10 was not cured by the BPO paste. Without wishing to be bound by theory, it is believed that the silicone oil inhibited the curing process. The cohesion of the PSA was poor. In addition, the film appearance was poor. The amount of each starting material and the results are summarized in Table 3 below.

[0113] In this Reference Example 11, samples 11-14 were prepared by mixing 50 parts by weight of the emulsion 1 prepared as described in Reference Example 1 with the dispersion prepared as described in Reference Example 8. Each of the resulting samples was then coated on a PET film having a thickness of 50 μm and cured at 80° C. for 2 minutes and at 180° C. for 5 minutes. The 180° peel adhesion, 200° C. cold peel adhesion, and visual appearance of each sample were measured. The amount of each starting material and the results are shown in Table 3 below.

[0114] In this Reference Example 12, Sample 15 was prepared by mixing 50 parts by weight of Emulsion 1 prepared as described in Reference Example 1 with 0.05 parts by weight of KATHON LX-150 and 2.42 parts by weight of Dispersion I prepared as described in Reference Example 8. The resulting Sample 15 was then coated on a PET film having a thickness of 50 μm and cured at 80° C. for 2 minutes and at 180° C. for 5 minutes. 180° peel adhesion, 200° C. cold peel adhesion, and visual appearance were measured. The amount of each starting material and the results are shown in Table 3 below.

[0115] Table 3 - PSA emulsion samples prepared using emulsion 1

[0116]

[0117] Samples 11-15 demonstrate that the use of a dispersion of benzoyl peroxide with water and alcohol prepared according to Reference Example 8 can provide unexpected benefits of improved adhesion and cold peel results to PSA emulsions. Samples 11, 12, and 15 further demonstrate that excellent visual appearance can also be achieved when OCS is used in place of an organic surfactant.

[0118] In this reference example 13, samples 16-21 were prepared as follows. 50 parts by weight of an emulsion prepared according to one of the above reference examples 2-7 was combined with a certain amount of dispersion I prepared according to the above reference example 8 to form a curable PSA emulsion sample. Each sample was then coated on a PET film having a thickness of 50 um and cured at 80°C for 2 minutes and at 180°C for 5 minutes. The 180° peel adhesion, 200°C cold peel adhesion and visual appearance of each cured sample were measured. The amount and results of each starting material are shown in Table 4 below.

[0119] Table 4

[0120]

[0121] Reference Example 14 - Test method for gum viscosity

[0122] Standard method for measuring gum viscosity using the Alpha Technologies RAP 2000

[0123] 1) This is at 50°C using a 1 degree arc running at 100 rpm, 1 degree arc equals 13.96%

[0124] strain.

[0125] 2) Load between 5g and 5.5g of gum between 0.023mm polyester sheets.

[0126] The use of polyester sheet does have a big effect, especially at lower gum viscosities, but makes cleanup fairly easy.

[0127] 3) Analyze the sample for 6 minutes and record the data by the software after 2 minutes, 3 minutes, 4 minutes, 5 minutes and 6 minutes. These are averaged to give the reported value. In some cases,

[0128] The test time was reduced to 3 minutes and the average between 2 and 3 minutes was recorded.

[0129] Reference Example 15-Test Method for Polymer Viscosity

[0130] Brookfield Viscometer Procedure:

[0131] 1) Power up the RVDV-1prime Viscometer and zero the sensor. Clean the guard leg and attach it to the back of the viscometer pivot cup. Clean and inspect the spindle before use.

[0132] 2) Dispense the liquid sample into a 16 oz polypropylene jar. Insert the probe stem of a digital thermometer into the sample and use to stir the contents vigorously, but not to the extent of entraining new bubbles. The stirring is intended to disrupt the internal network of moderate thixotropy to minimize time dependence during measurement.

[0133] 3) Immerse the rotor at an angle so as not to entrain new bubbles. Then connect the rotor to the rotor coupling using the left stage thread. The rotor speed of the RVDV-IPrime viscometer is selected from fixed increments ranging from 0.3 rpm to 100 rpm. The applied resistance is displayed on the instrument.

[0134] 4) During these evaluations, the single point QC method was undergoing method development. The decision to use the RV4-spindle at 20 rpm was independent of the conditions employed by the guar gum industry for 1% solution QC testing. The full range of viscosities spanned by the RV4-spindle and 20 rpm speed combination is 1000 cst to 10000 cst. Therefore, the target range is a subset near the center of the full range. The instrument torque in the target viscosity range is approximately 50% of full scale (instrument tolerance decreases from 11% at 10% full scale torque to 3% at 50% full scale torque. Going from 50% to 100% full scale torque only yields an improvement in instrument tolerance of 2%)

[0135] Reference Example 16-Adhesion Test Method

[0136] Crepe paper was coated with a sample of the curable silicone pressure-sensitive adhesive composition prepared and cured as described above. The coated crepe paper was cut into 1 inch wide tapes and adhered to a clean standard steel plate. A 1 kg roller was applied twice. The resulting article was aged at room temperature for 30 minutes. Then, the pressure-sensitive adhesive was peeled off using an adhesion tester (ChemInstruments AR-1500) to test the peel force.

[0137] Reference Example 17 - 200°C Cold Peel Test Method. Crepe paper was coated with a sample of the curable silicone pressure sensitive adhesive composition prepared and cured as described above. The coated crepe paper was cut into 1 inch wide tape strips which were adhered to a clean standard steel plate. The resulting sample was aged at room temperature for 30 minutes. The sample was then placed in an oven at 200°C for 30 minutes. The sample was then placed outside the oven and cooled to room temperature under ambient conditions. The tape was peeled from the substrate and visually evaluated for residue and migration.

[0138] Reference Example 18 - The visual appearance of each sample was evaluated by the naked eye.

[0139] Use of terminology

[0140] Summary of the invention and description abstract are hereby incorporated by reference. Unless otherwise specified in the context of this specification, all amounts, ratios and percentages are by weight. Unless otherwise specified in the context of this specification, the articles "one", "a kind of" and "the" each refer to one (a kind) or more (multiple). The disclosure of a range includes the range itself and any values ​​and endpoints contained therein. For example, the disclosure of a range of 20 to 50 not only includes a range of 20 to 50, but also includes 20, 30, 37.5, 45 and 50 and any other number contained in the range individually. In addition, the disclosure of a range of, for example, 20 to 50 includes, for example, a subset of 20 to 37, 38 to 45 and 46 to 50, and any other subset contained in the range. Similarly, the disclosure of a Markush group includes the entire group and also includes any individual member and subgroup contained therein. For example, disclosure of the Markush groups alkyl, alkenyl, and aryl includes the individual member alkyl; the subgroups alkyl and aryl; and any other individual members and subgroups subsumed therein.

[0141] Abbreviations used in this application are as defined in Table 5 below.

[0142] Table 5

[0143]

[0144]

[0145] The Mn of gums and other starting materials (such as E) polyorganosilicate resins and H) polymers) can be measured by GPC according to the following technique. The chromatographic equipment is a Waters 2695 separation module equipped with a vacuum degasser and a Waters 2414 refractive index detector. Three Styragel TM HR column (300 mm × 7.8 mm) (molecular weight separation range is 100 to 4,000,000), and then through Styragel TMGuard column (30mm × 4.6mm) is separated. Use the certified toluene flowing with 1.0mL / min as eluent for analysis, and both post and detector are heated to 45 ℃. Prepare 0.5%wt. / v sample by weighing 0.025g pure sample in 12mL glass vial and diluting with 5ml toluene. After centrifugation or filtering by 0.45μm PTFE filter, the sample solution is transferred to a glass autosampler vial. Used the injection volume of 100μl, and collected data for 38 minutes. Use Waters Empower GPC software to collect data and analyze. Relative to the calibration curve (3rd order) created by the polystyrene standards using molecular weight range of 370g / mol-1,270,000g / mol, the molecular weight average is determined.

[0146] Embodiments of the present invention

[0147] In a first embodiment, a method for preparing a curable silicone pressure sensitive adhesive emulsion comprises:

[0148] 1) preparing a dispersion comprising

[0149] A) >0 wt. % to <55 wt. % benzoyl peroxide;

[0150] B) 0% to ≤ 25% by weight of water; and

[0151] C) >20 wt% of a phenoxy-functionalized alcohol selected from the group consisting of 1-phenoxy-2-propanol and 2-phenoxyethan-1-ol; and

[0152] 2) combining the dispersion with a starting material comprising

[0153] D) a dihydroxy-terminated polydiorganosiloxane gum;

[0154] E) polyorganosilicate resin;

[0155] F) alcohol ethoxylate surfactant;

[0156] G) additional water;

[0157] Optionally H) a bishydroxy-terminated polydiorganosiloxane polymer;

[0158] Optionally 1) a solvent; and

[0159] Optionally J) a biocide.

[0160] In a second embodiment, the method according to the first embodiment further comprises:

[0161] i) mixing starting materials comprising D) and E) and optionally H) and / or I);

[0162] ii) adding the starting material F) to the product of step i) and mixing;

[0163] iii) adding the starting material G) to the product of step ii) and emulsifying; and thereafter

[0164] iv) adding said dispersion from step 1) to the product of step iii).

[0165] In a third embodiment, in the method according to the first or second embodiment, the dispersion comprises 20% to 50% A) benzoyl peroxide, 2% to 25% B) water, and 25% to 78% 1-phenoxy-2-propanol.

[0166] In a fourth embodiment, in the method according to the first or second embodiment, the dispersion comprises 20% to 50% A) benzoyl peroxide, 2% to 25% B) water, and 25% to 78% 2-phenoxyethan-1-ol.

[0167] In a fifth embodiment, in the process according to any one of the preceding embodiments, the starting material D) is present in an amount of 7% to 30% by weight, based on the weight of the emulsion, and the starting material D) has the formula Each R 1 are independently selected monovalent hydrocarbon groups; and the value of subscript a is sufficient to impart to the gum a number average molecular weight of ≥ 300,000 g / mol.

[0168] In a sixth embodiment, in a process according to any one of the preceding embodiments, starting material E) is present in an amount sufficient to provide a weight ratio of starting material E) / [starting material D)+starting material H)][resin / (gum+polymer) ratio] of 0.5 to 2.0, and starting material E) is selected from the group consisting of:

[0169] E-1) Unit type (R M 3SiO 1 / 2 ) z (SiO 4 / 2 ) o X 2 p The end-capped resin, wherein each R M is an independently selected monovalent hydrocarbon group, each X 2is a hydrolyzable substituent, subscripts z and o have values ​​such that o>1 and subscript z>4, the amount (o+z) has a value sufficient to impart an Mn of 1500 g / mol to 5,000 g / mol to the end-capped resin; and subscript p has a value sufficient to impart a hydrolyzable group content of 0% to <2% to the end-capped resin;

[0170] E-2) Unit type (R M 3SiO 1 / 2 ) z’ (SiO 4 / 2 ) o’ X 2 p’ An uncapped resin wherein subscripts z' and o' have values ​​such that o'>1 and subscript z'>4, the amount (o'+z') has a value sufficient to impart an Mn of 1,500 g / mol to 5,000 g / mol to the uncapped resin; and the value of subscript p' is sufficient to impart a hydrolyzable group content of ≥2% to 10% to the uncapped resin.

[0171] In a seventh embodiment, in the method according to any one of the preceding embodiments, the starting material F) is present in an amount of 5% to 10% based on the weight of the curable silicone pressure-sensitive adhesive emulsion, and the starting material F) is selected from the group consisting of a polyether-modified polyorganosilicate (MQ) resin and an organic alcohol ethoxylate.

[0172] In an eighth embodiment, in the method according to any one of the preceding embodiments, the starting material G) is added in an amount of 20 to 40 wt % based on the weight of the curable silicone pressure-sensitive adhesive emulsion.

[0173] In a ninth embodiment, in the method according to any one of the preceding embodiments, the starting material H) the bishydroxyl-terminated polydiorganosiloxane polymer is present in an amount of 10% to 15% by weight of the curable silicone pressure sensitive adhesive emulsion, and the bishydroxyl-terminated polydiorganosiloxane polymer has the formula Each R 1 are independently selected monovalent hydrocarbon groups, and the value of subscript b is sufficient to impart a viscosity of ≤ 200,000 cs to the bishydroxy terminated polydiorganosiloxane polymer.

[0174] In a tenth embodiment, in the process according to any of the preceding embodiments, the starting material I) is present in an amount of >0 wt% to 20 wt% and comprises a mixture of aromatic hydrocarbons.

[0175] In an eleventh embodiment, in the process according to any one of the preceding embodiments, the starting material J) is present in an amount of 0.1% to 5%.

[0176] In a twelfth embodiment, the method according to any one of the preceding embodiments further comprises devolatilizing the curable silicone pressure sensitive adhesive emulsion during step 2) of the method and / or before completing adding G) the water in step 2).

[0177] In a thirteenth embodiment, the method according to any of the preceding embodiments further comprises forming an adhesive article by a technique comprising applying the curable silicone pressure sensitive adhesive emulsion to a substrate and curing.

[0178] In a fourteenth embodiment, the method according to the thirteenth embodiment further comprises using the adhesive article in an industrial tape.

[0179] In a fifteenth embodiment, the method according to the thirteenth embodiment further comprises using the adhesive article in a personal care product.

[0180] In a sixteenth embodiment, the method according to the thirteenth embodiment further comprises using the adhesive article in a healthcare product.

Claims

1. A method for preparing a curable silicone pressure-sensitive adhesive emulsion, the method comprising: 1) preparing a dispersion comprising A) >0 wt% and <55 wt% benzoyl peroxide; B) ≥ 0 wt. % and ≤ 25 wt. % water; as well as C) >20 wt% of a phenoxy-functional alcohol selected from the group consisting of 1-phenoxy-2-propanol and 2-phenoxyethanol; and 2) combining the dispersion with a starting material comprising D) a dihydroxy-terminated polydiorganosiloxane gum; E) polyorganosilicate resin; F) alcohol ethoxylate surfactant; G) additional water; Optionally H) a bishydroxy-terminated polydiorganosiloxane polymer; Optionally 1) a solvent; and Optionally J) a biocide.

2. The method according to claim 1, wherein the method further comprises: i) mixing starting materials comprising D) and E) and optionally H) and / or I); ii) adding the starting material F) to the product of step i) and mixing; iii) adding the starting material G) to the product of step ii) and emulsifying; and thereafter iv) adding said dispersion from step 1) to the product of step iii).

3. A method according to claim 1 or claim 2, wherein the dispersion comprises 20% to 50% A) benzoyl peroxide, 2% to 25% B) water and 25% to 78% 1-phenoxy-2-propanol.

4. The method of claim 1 or claim 2, wherein the dispersion comprises 20% to 50% A) benzoyl peroxide, 2% to 25% B) water, and 25% to 78% 2-phenoxyethanol.

5. The method according to claim 1 or claim 2, wherein the starting material D) is present in an amount of 7% to 30% by weight based on the weight of the emulsion, and the starting material D) has the formula Each R 1 are independently selected monovalent hydrocarbon groups; and the value of subscript a is sufficient to impart to the gum a number average molecular weight of ≥ 300,000 g / mol.

6. The process according to claim 1 or claim 2, wherein the starting material E) is present in an amount sufficient to provide a weight ratio of starting material E) / [starting material D)+starting material H)] of 0.5 to 2.0, and the starting material E) is selected from the group consisting of: E-1) Unit type (R M 3SiO 1 / 2 ) z (SiO 4 / 2 ) o X 2 p The end-capped resin, wherein each R M is an independently selected monovalent hydrocarbon group, each X 2 is a hydrolyzable substituent, subscripts z and o have values ​​such that o>1 and subscript z>4, the amount (o+z) has a value sufficient to impart an Mn of 1500 g / mol to 5,000 g / mol to the end-capped resin; and subscript p has a value sufficient to impart a hydrolyzable group content of ≥0% and <2% to the end-capped resin; E-2) Unit type (R M 3SiO 1 / 2 ) z’ (SiO 4 / 2 ) o’ X 2 p’ An uncapped resin wherein subscripts z' and o' have values ​​such that o'>1 and subscript z'>4, the amount (o'+z') has a value sufficient to impart an Mn of 1,500 g / mol to 5,000 g / mol to the uncapped resin; and the value of subscript p' is sufficient to impart a hydrolyzable group content of ≥2% to 10% to the uncapped resin.

7. The method according to claim 1 or claim 2, wherein the starting material F) is present in an amount of 5% to 10% based on the weight of the curable silicone pressure-sensitive adhesive emulsion, and the starting material F) is selected from the group consisting of polyether-modified polyorganosilicate resins and organic alcohol ethoxylates.

8. The method according to claim 1 or claim 2, wherein the starting material G) is added in an amount of 20 to 40 wt% based on the weight of the curable silicone pressure-sensitive adhesive emulsion.

9. The method of claim 1 or claim 2, wherein H) the bis-hydroxyl-terminated polydiorganosiloxane polymer is present in an amount of 10% to 15% by weight of the curable silicone pressure sensitive adhesive emulsion, and the bis-hydroxyl-terminated polydiorganosiloxane polymer has the formula Each R 1 are independently selected monovalent hydrocarbon groups, and the value of subscript b is sufficient to impart a viscosity of ≤ 200,000 cs to the bishydroxy terminated polydiorganosiloxane polymer.

10. The process according to claim 1 or claim 2, wherein the starting material I) is present in an amount of >0% to 20% by weight and comprises a mixture of aromatic hydrocarbons.

11. A process according to claim 1 or claim 2, wherein the starting material J) is present in an amount of 0.1% to 5%.

12. The method of claim 1 or claim 2, further comprising devolatilizing the curable silicone pressure sensitive adhesive emulsion during step 2) of the method and / or before completing adding G) the water in step 2).

13. The method of claim 1 or claim 2, further comprising forming an adhesive article by a technique comprising applying the curable silicone pressure sensitive adhesive emulsion to a substrate and curing.

14. The method of claim 13, further comprising using the adhesive article in an industrial tape or a personal care product.

15. The method of claim 13, further comprising using the adhesive article in a healthcare product.

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