Process for preparing a waterborne dispersion of solvent-free polyorganosiloxane pellets and silicone pressure sensitive adhesive base

Abstract

A method for preparing an aqueous dispersion of a silicone pressure sensitive adhesive base includes using solvent-free polyorganosiloxane pellets containing a polyorganosilicate resin and a polyorganosiloxane gum. The aqueous dispersion of the silicone pressure sensitive adhesive base can be combined with a free radical initiator and dried and cured to form a silicone pressure sensitive adhesive.

Description

[0001] Cross-references to related applications

[0002] none. Technical Field

[0003] This invention relates to a method for preparing an aqueous dispersion of a silicone pressure-sensitive adhesive base material. More specifically, this invention relates to a method for preparing an aqueous dispersion of a silicone pressure-sensitive adhesive base material, which may be combined with a free radical initiator and dried and cured to form a silicone pressure-sensitive adhesive. The method for preparing the aqueous dispersion includes using solvent-free polysiloxane granules composed of a polysilicate resin and a polysiloxane resin. Background Technology

[0004] Silicone pressure-sensitive adhesives (PSAs) have a variety of end-use applications, such as mica tapes and / or masking tapes with excellent heat resistance, stable adhesion, and wetting properties. However, most silicone PSA products on the market are used in BTX (benzene, toluene, and xylene) solvents. There is an industrial need for PSA products that can be used with low- or no organic solvents (such as BTX). The silicone compositions that cure to form silicone PSAs typically contain polysiloxane resins and polysilicate resins.

[0005] Polysiloxane resins are typically produced in aromatic solvents because they are solid at room temperature (RT). Without solvents, the resins are usually in powder or flake form, with very low bulk density, and can be difficult to store and transport. Powders may be inconvenient to handle and transport during the manufacture of silicone compositions, such as silicone-curable pressure-sensitive adhesive compositions. Furthermore, flake resins typically have high glass transition temperatures and high melting temperatures, making it difficult to uniformly blend with other components, especially polysiloxane resins, during the preparation of silicone compositions.

[0006] Granules are a widely used form of starting material delivery in the plastics industry. Densely packaged granules can be easily stored, transported, and conveyed using common machinery such as belt or screw feeders. However, the use of granules is limited in the silicone industry.

[0007] Past attempts to manufacture granules comprising siloxane resins and polydiorganosiloxane polymers involved dissolving the resin in a solvent or combining the resin and polymer in a solvent, followed by solvent removal. The resulting combination itself contained residual solvent.

[0008] Problems to be solved

[0009] Therefore, the silicone industry, particularly the silicone pressure-sensitive adhesive industry, requires granular forms of polyorganosilicate resins that are easy to transport and store in order to improve manufacturing and mixing efficiency when combining polyorganosilicate resins with other starting materials used in products such as silicone curable pressure-sensitive adhesive compositions. A method is needed to manufacture such granules and to use them to form aqueous dispersions of silicone pressure-sensitive adhesive base materials that contain little or no organic solvents such as BTX. Summary of the Invention

[0010] A method for preparing solvent-free polyorganosiloxane granules and an aqueous dispersion of an organosilicon pressure-sensitive adhesive base material prepared from the solvent-free polyorganosiloxane granules is disclosed. The method includes:

[0011] 1) An extruder is provided, the extruder including a barrel having a first feed port, a second feed port and an outlet having a die; a heating device configured to heat the barrel; and a screw mechanism housed within the barrel, wherein the first feed port and the second feed port are configured to introduce starting materials into the extruder, the screw mechanism being capable of mixing the starting materials from the first feed port and the second feed port and conveying the starting materials to the outlet, the first feed port being located upstream of the second feed port and the second feed port being located upstream of the outlet;

[0012] 2) At least a portion of i) solvent-free polydiorganosiloxane resin is added to the extruder through the first feed port, and ii) solvent-free polyorganosilicate resin is added to the extruder through the second feed port, wherein the resin and the resin are added in a certain amount such that the weight ratio of resin to resin is 2.1:1 to 5:1.

[0013] 3) The solvent-free polydiorganosiloxane resin and the solvent-free polyorganosilicate resin are mixed in the barrel, and the barrel is heated to a temperature of 200°C to 250°C to form a mixture;

[0014] 4) The mixture is conveyed through the mold at the outlet to form a wire;

[0015] 5) Cool the wire material leaving the mold, and

[0016] 6) The wire is crushed to prepare these solvent-free polyorganosiloxane granules;

[0017] 7) Feed the following starting materials into the dispersing apparatus: the granules prepared in step 6); surfactant; water; and optionally additional polydiorganosiloxane resin, the amount of which is sufficient to adjust the resin:resin ratio to 0.4:1 to 3:1; and

[0018] 8) The starting materials from step 7) are mixed and heated in the dispersion apparatus to produce the aqueous dispersion of the silicone pressure-sensitive adhesive base.

[0019] A method for preparing an aqueous dispersion of a silicone pressure-sensitive adhesive composition includes: performing the method for preparing the aqueous dispersion of the silicone pressure-sensitive adhesive base material, and combining the aqueous dispersion of the silicone pressure-sensitive adhesive base material with an additional starting material including an initiator. The aqueous dispersion of the silicone pressure-sensitive adhesive composition can be used in methods including coating the aqueous dispersion of the silicone pressure-sensitive adhesive composition onto a surface substrate and curing it to form an adhesive article. Attached Figure Description

[0020] Figure 1(A) shows a schematic diagram of an apparatus suitable for preparing granules applicable to the present invention.

[0021] Figure 1(B) shows a schematic diagram of an apparatus for preparing granules according to the following comparative example 2.

[0022] Figure 1(C) shows a schematic diagram of an alternative apparatus suitable for preparing pellets applicable to the present invention.

[0023] Figure 2 The pellets prepared according to the example section of this article are shown. Figure 2 (A) shows the pellets prepared according to Example 1 below. Figure 2 (B) shows the pellets prepared according to the following comparative example 2. Figure 2 (C) shows the pellets prepared according to Example 3 below.

[0024] Figure 3 A partial cross-section of the adhesive article 400 is shown. The adhesive article includes a pressure-sensitive adhesive 401 prepared by curing the pressure-sensitive adhesive composition described herein onto a first surface 402 of a membrane substrate 103. The article 400 also includes a second substrate 404 mounted to an opposing surface 405 of the membrane substrate 403. Detailed Implementation

[0025] The solvent-free polyorganosiloxane granules (granules) prepared in the above method comprise polydiorganosiloxane resin (resin) and polyorganosilicate resin (resin). Alternatively, the granules may consist essentially of resin and resin. Alternatively, the granules may consist of resin and resin. The amount of resin and resin in the granules is sufficient to provide a resin:resin weight ratio (R:G ratio) of 2.1:1 to 5:1. Alternatively, the R:G ratio may be 2.1:1 to 4.5:1, alternatively 2.4:1 to 4.0:1, alternatively 3.0:1 to 4.0:1, alternatively 2.1:1 to 3.5:1, alternatively 2.4:1 to 3.0:1, alternatively 2.4:1 to 2.9:1, alternatively 2.7:1 to 2.9:1, and alternatively 2.4:1 to 2.5:1.

[0026] gum

[0027] The resin in the granules may be a polydiorganosiloxane resin capped with aliphatic unsaturated groups or hydroxyl groups. As measured by GPC according to the test method in Reference Example 1, beginning in column 31 of U.S. Patent 9,593,209, the resin has a number-average molecular weight (Mn) of ≥ 150,000 g / mol, alternatively 200,000 g / mol to 1,000,000 g / mol, alternatively 300,000 g / mol to 800,000 g / mol, and alternatively 500,000 g / mol to 1,000,000 g / mol.

[0028] Gum can have a unit formula (G-1): (R 3 R 2 2SiO 1 / 2 ) a (R 2 2SiO 2 / 2 ) b (R 2 SiO 3 / 2 ) c , where each R 2 Independently selected from the group consisting of alkyl groups having 1 to 18 carbon atoms and aryl groups having 6 to 18 carbon atoms, and each R 3 The curable group is an independently chosen group, with subscript a ≥ 2, subscript b > 1500, and subscript c ≥ 0, provided that the amount (a + b + c) is sufficient to give the resin the aforementioned Mn. Alternatively, subscript a can be 2. Alternatively, subscript b can be 2500 to 8000, alternatively 4000 to 6000, alternatively 5300 to 6000, and alternatively 5400 to 5900. Alternatively, subscript c can be 0.

[0029] In the unitary form (G-1), R 2 It can be an alkyl group having 1 to 18 carbon atoms. Alternatively, each R 2 It can have 1 to 12 carbon atoms, and alternatively 1 to 6 carbon atoms. "alkyl" means a cyclic, branched, or unbranched saturated monovalent hydrocarbon group. 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, as well as branched alkyl groups having 6 to 18 carbon atoms; and cyclic alkyl groups such as cyclopentyl and cyclohexyl. Alternatively, R 2 One or more instances of aryl groups can be aryl groups. "Aryl" means a cyclic, fully unsaturated hydrocarbon group. Examples of aryl groups include, but are not limited to, cyclopentadienyl, phenyl, anthraceneyl, and naphthyl. Monocyclic aryl groups may have 5 to 9 carbon atoms, alternatively 6 to 7 carbon atoms, and alternatively 5 to 6 carbon atoms. Polycyclic aryl groups may have 10 to 17 carbon atoms, alternatively 10 to 14 carbon atoms, and alternatively 12 to 14 carbon atoms. Alternatively, each R 2 It can be independently selected from methyl and phenyl. Alternatively, each R 2 It can be an alkyl group. Alternatively, each R 2 It can be methyl.

[0030] In the unitary form (G-1), each R 3 It is a curable group. Each R 3 It can be independently selected from the group consisting of OH and monovalent aliphatic unsaturated hydrocarbon groups having 2 to 18 carbon atoms. Alternatively, R 3 The aliphatic unsaturated hydrocarbon group can have 2 to 12 carbon atoms, and alternatively 2 to 6 carbon atoms. Suitable monovalent aliphatic unsaturated hydrocarbon groups include alkenyl and ynyl groups. "Alkenyl" means a monovalent hydrocarbon group having one or more carbon-carbon double bonds. Alkenyl groups can be straight-chain, branched, or cyclic. Examples of suitable alkenyl groups are vinyl; allyl; propenyl (e.g., isopropenyl and / or n-propenyl); and butenyl, pentenyl, hexenyl, and heptenyl (including branched isomers having 4 to 7 carbon atoms); and cyclohexenyl. "Yynyl" means a monovalent hydrocarbon group having one or more carbon-carbon triple bonds. Yynyl groups can be branched, unbranched, or cyclic. Suitable ynyl groups are exemplified by ethynyl, propynyl, and butynyl (also including branched isomers having 2 to 4 carbon atoms). Alternatively, R 3 The aliphatic unsaturated group can be alkenyl, such as vinyl, allyl or hexenyl.

[0031] Alternatively, each R2 It can be an alkyl group, each R 3 It can be independently selected from the group consisting of OH and alkenyl groups having 2 to 18 carbon atoms, where subscript a can be 2, subscript c can be 0, and subscript b can be 5300 to 6000. Alternatively, each R 2 It can be methyl; each R 3 It can be independently selected from the group consisting of OH, vinyl, allyl and hexenyl; subscript a can be 2; subscript c can be 0; and subscript b can be from 5400 to 5900.

[0032] Alternatively, the resin can be a dihydroxyl-terminated polydiorganosiloxane. Hydroxyl-functionalized polydiorganosiloxanes can have the unit formula (G-2): [R 2 2(HO)SiO 1 / 2 ]2(R 2 2SiO 2 / 2 ) d , where each R 2 As described above; the subscript d ≥ 0, provided that the subscript d has a value sufficient to give the resin the aforementioned Mn. Alternatively, the resin can be a dienyl-terminated polydiorganosiloxane. Dienyl-terminated polydiorganosiloxanes can have the unit formula (G-3): (R 2 2R 3’ SiO 1 / 2 )2(R 2 2SiO 2 / 2 ) d , where each R 2 As mentioned above; R 3' The subscript d is an alkenyl group as described above, and the subscript d ≥ 0, provided that the subscript d has a value sufficient to give the resin the aforementioned Mn value. Alternatively, the resin may be a combination of dihydroxyl-terminated polydiorganosiloxane and dienyl-terminated polydiorganosiloxane.

[0033] Gum is known in the art and can be prepared by methods such as the hydrolysis and condensation of corresponding organohalosilanes or the equilibrium of cyclic polydiorganosiloxanes. Gum is commercially available, for example, SILASTIC. ™SGM-36 is commercially available from Dow Silicones Corporation of Midland, Michigan, USA. Examples of resins applicable to this article include: i) dimethylvinylsiloxy-terminated polydimethylsiloxane, ii) dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylphenyl)siloxane, iii) dimethylvinylsiloxy-terminated poly(dimethylsiloxane / diphenyl)siloxane, iv) phenyl, methyl, vinyl-siloxy-terminated polydimethylsiloxane, v) dimethylhexenylsiloxy-terminated polydimethylsiloxane, vi) dimethylhexenyl-siloxy-terminated poly(dimethylsiloxane / methylphenyl)siloxane, vii) dimethylhexenylsiloxy-terminated poly(dimethylsiloxane / diphenyl)siloxane, vii) dimethylhexenylsiloxy-terminated poly(dimethylsiloxane / diphenyl)siloxane, viii) hydroxyl-terminated polydimethylsiloxane, ix) hydroxyl-terminated poly(dimethylsiloxane / methylphenyl)siloxane, x) hydroxyl-terminated poly(dimethylsiloxane / diphenyl)siloxane, xi) Combinations of two or more of i) to x). Alternatively, the resin may be selected from the group consisting of: i) dimethylvinylsiloxy-terminated polydimethylsiloxane, v) dimethylhexenylsiloxy-terminated polydimethylsiloxane, and combinations of i) and v). Alternatively, the resin may be selected from the group consisting of viii), ix), and x). Alternatively, the resin may be selected from the group consisting of i) and viii).

[0034] Polyorganosilicate resin

[0035] Polyorganosilicate resins (resins) include those of formula R M 3SiO 1 / 2 The single functional unit and the formula SiO 4 / 2 The four functional units (“Q units”), where each R M It is an independently selected monovalent hydrocarbon group. Applicable to R M The monovalent hydrocarbon group can have 1 to 20 carbon atoms, alternatively 1 to 12 carbon atoms, alternatively 1 to 8 carbon atoms, alternatively 1 to 4 carbon atoms, and alternatively 1 to 2 carbon atoms. Alternatively, R M The hydrocarbon group can be selected from the group consisting of: alkyl, alkenyl, and aryl groups; alternatively alkyl and aryl groups; alternatively alkyl and alkenyl groups; and alternatively alkyl groups. Alkyl and aryl groups are as described above for R. 2 As described above, and the alkenyl group is as described above for R 3 The alkenyl group. Alternatively, in the resin, each R M It can be independently selected from the group consisting of alkyl, alkenyl, and aryl groups. Alternatively, each R...M It may be selected from methyl, vinyl, and phenyl. Alternatively, at least one-third, or at least two-thirds, of the R... M The functional group is a methyl group. Alternatively, an example of a monofunctional unit could be (Me3SiO2). 1 / 2 (Me2PhSiO) 1 / 2 ) and (Me2ViSiO 1 / 2 The resin can be used as a starting material (H) and dissolved in solvents such as those described herein, exemplified by liquid hydrocarbons such as benzene, toluene, xylene, and heptane, or dissolved in liquid organosilicon compounds such as low-viscosity linear and cyclic polydiorganosiloxanes.

[0036] During preparation, the resin comprises the aforementioned monofunctional and tetrafunctional units, and the polyorganosiloxane further comprises units having silanol (silicon-bonded hydroxyl) groups and may include formula Si(OSiR) M 3)4 new pentamer, in which R M As described above. As in Example 2, paragraph 32 of U.S. Patent 9,593,209, Si 29 Nuclear magnetic resonance (NMR) spectroscopy can be used to measure the molar ratio of M units to Q units, where the ratio is expressed as {M(resin) + (M(new pentamer)} / {Q(resin) + Q(new pentamer)}, and represents the molar ratio of the total number of triorganosylsiloxy groups (monofunctional units) in the resin and new pentamer portions of the polyorganosilicate resin to the total number of silicate groups (Q units) in the resin and new pentamer portions.

[0037] The Mn content of the resin depends on various factors, including the presence of Mn derived from R. M The type of hydrocarbon group indicated. When the peak representing the new pentamer is excluded from the measurement, the Mn of the resin refers to the number-average molecular weight measured using GPC according to the procedure in Reference Example 1, Column 31 of U.S. Patent 9,593,209. The Mn of the resin can be greater than 2,000 g / mol, alternatively from 2,500 g / mol to 15,000 g / mol. Alternatively, the Mn of the resin can be from 2,000 g / mol to 8,000 g / mol, alternatively from 2,900 g / mol to 6,000 g / mol, and alternatively from 2,900 g / mol to 5,000 g / mol.

[0038] The resin can be prepared by any suitable method, such as co-hydrolysis of the corresponding silane or by a silica hydrosol end-capping method. The resin can be prepared by silica hydrosol end-capping methods, 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 aforementioned method by Daudt et al. involves reacting a silica hydrosol under acidic conditions with a hydrolyzable triorganosilane (such as trimethylchlorosilane), a siloxane (such as hexamethyldisiloxane), or a mixture thereof, and recovering copolymers having monofunctional and tetrafunctional units. The resulting copolymers typically contain 2% to 5% by weight of hydroxyl groups.

[0039] Intermediates used in resin preparation can be triorganosilanes and silanes having four hydrolyzable substituents or alkali metal silicates. Triorganosilanes may have the formula R M 3SiX 1 , where R M As mentioned above and X 1 This indicates a hydrolyzable substituent. Silanes with four hydrolyzable substituents can have the formula SiX. 2 4, where each X 2 It can be halogenated, alkoxylated, or hydroxylated. Suitable alkali metal silicates include sodium silicate.

[0040] The resins prepared as described above typically contain, for example, the formula HOSi. 3 / 2 and / or HOR M 2SiO 1 / 2 Silicon-bonded hydroxyl groups. Polyorganosilicate resins may include up to 5% by weight of silicon-bonded hydroxyl groups, or alternatively up to 2% by weight, on the same basis. The concentration of silicon-bonded hydroxyl groups present in the resin can be determined using Fourier transform infrared (FTIR) spectroscopy according to ASTM standard E-168-16. For some applications, it may be desirable for the amount of silicon-bonded hydroxyl groups to be less than 0.7%, or alternatively less than 0.3%, or alternatively less than 1%, and alternatively from 0.3% to 0.8%. Silicon-bonded hydroxyl groups formed during resin preparation can be converted into trialkylsiloxane groups or different hydrolyzable groups by reacting the resin with a silane, disiloxane, or disilazane containing appropriate terminal groups. Silanes containing hydrolyzable groups can be added in amounts exceeding the molar amount required to react with the silicon-bonded hydroxyl groups on the resin.

[0041] Alternatively, the resin may also include 2% or less, alternatively 0.7% or less, alternatively 0.3% or less, and alternatively 0.3% to 0.8% of XSiO₂. 3 / 2 and / or XRM 2SiO 1 / 2 The unit represented, where R M As mentioned above, and X represents a hydrolyzable substituent, as stated above regarding X. 1 As stated above.

[0042] Alternatively, the resin may have terminal aliphatic unsaturated groups. Resins having terminal aliphatic unsaturated groups can be prepared by reacting the product of Daudt et al. with a capping agent containing unsaturated organic groups and a capping agent without aliphatic unsaturation in sufficient amounts to provide 3 to 30 mol% of unsaturated organic groups in the final product. Examples of capping agents include, but are not limited to, silazanes, siloxanes, and silanes. Suitable capping agents are known in the art and are exemplified in U.S. Patents 4,584,355, 4,591,622, and 4,585,836. A single capping agent or a mixture of such agents can be used to prepare such resins.

[0043] Alternatively, the resin may comprise the unitary formula (R-1): (R 1 R 2 2SiO 1 / 2 ) w (R 2 3SiO 1 / 2 ) x (SiO 4 / 2 ) y X z , where R 2 And X as described above, each R 1 It is an independently chosen aliphatic unsaturated group with 2 to 18 carbon atoms (such as the one mentioned above for R). 3 The groups are defined such that the subscripts w, x, y, and z have average values ​​such that w ≥ 0, x ≥ 0, y > 1, z ≥ 0, and the amount (w + x) > 4. Alternatively, each R in the unit formula (R-1) 2 It can be alkyl, or alternatively methyl. The amount (w + x + y + z) is sufficient to give the resin a weight-average molecular weight of 2,000 g / mol to 15,000 g / mol, or alternatively 8,000 to 10,000, or alternatively 9,000 to 9,500. Alternatively, each R 1The resin can be independently selected from the group consisting of vinyl, allyl, and hexenyl. Alternatively, each X can be OH. Alternatively, the subscript x can be 40 to 55, or alternatively 43 to 50. Alternatively, the subscript y can be 45 to 65, or alternatively 50 to 57. Alternatively, the subscript z can be 0 to a value sufficient to provide the resin with up to 5% by weight of OH groups, or alternatively up to 2% by weight and alternatively up to 0.7% by weight of OH groups. Alternatively, the resin can comprise the unit formula (R-2): (R 2 3SiO 1 / 2 ) v (SiO 4 / 2 ) y X z , where R 2 X, subscript y, and subscript z are as described above, and subscript v > 4.

[0044] The resins described above can be prepared in a solvent, but then volatile substances are removed. For example, the resin can be dried by heating to a temperature up to 150°C to remove the solvent without degrading the resin. For example, the resin can be heated, optionally under reduced pressure, to remove the solvent. Solvent-free polysilicate resins contain undetectable or 0 to 2%, alternatively 0% to 1%, alternatively 0 ppm to 100 ppm of residual solvent, such as residual solvent from the resin manufacturing process. In methods for preparing granules, the solvent-free polysilicate resin used can be in powder or flake form.

[0045] Method for preparing solvent-free polyorganosiloxane granules

[0046] Solvent-free polysiloxane granules (granules) comprise the aforementioned resin and gum. The granules are solvent-free, and as used herein, the term "solvent-free" means that no solvent was intentionally added during the manufacture of the granules. Those skilled in the art will recognize that polysiloxane resins can be prepared using solvents; however, the solvent-free polysiloxane resins used in this method have had volatile substances removed as described above to remove the solvent, and no solvent is added during the preparation of the granules. Solvent-free polysiloxane resins can be fed into an extruder in flake or powder form.

[0047] Methods for preparing the above-mentioned granules include:

[0048] 1) An extruder is provided, the extruder including a barrel having a first feed port, a second feed port and an outlet having a die; a heating device configured to heat the barrel; and a screw mechanism housed within the barrel, wherein the first feed port and the second feed port are configured to introduce starting materials into the extruder, the screw mechanism being capable of mixing the starting materials from the first feed port and the second feed port and conveying the starting materials to the outlet, the first feed port being located upstream of the second feed port and the second feed port being located upstream of the outlet;

[0049] 2) Adding at least a portion of the resin as described above to the extruder through the first feed port, and adding the resin as described above to the extruder through the second feed port, wherein the resin and the resin are added in a certain amount such that the weight ratio of resin to resin is 2.1:1 to 5:1.

[0050] 3) Mix the gum and resin in the barrel while heating the barrel at a temperature of 200°C to 250°C to form a mixture;

[0051] 4) The mixture is conveyed through the mold at the outlet to form a wire;

[0052] 5) Cool the wire material leaving the mold, and

[0053] 6) Crush the wire material to prepare the granules.

[0054] The above method may optionally include preparing a solvent-based polyorganosilicate resin before step 2) and removing volatile substances from the solvent-based polyorganosilicate resin to form a solvent-free polyorganosilicate resin.

[0055] In the method described above, all the resin can be added to the first feed inlet. Alternatively, up to 15% of the resin (e.g., blended with resin) can be added to the second feed inlet.

[0056] Steps 5) and 6) can be performed sequentially or simultaneously. For example, steps 5) and 6) can be performed simultaneously (i.e., in one piece of equipment), such as an underwater granulator. Alternatively, steps 5) and 6) can be performed sequentially using separate equipment components (such as a water bath for cooling the filament in step 5) and a separate granulator in step 6). Commercially available equipment can be used to perform the above methods. Extruders (e.g., twin-screw extruders) and granulation equipment are known in the art and are commercially available. The resulting granules prepared as described above can be used to prepare aqueous dispersions of silicone pressure-sensitive adhesive base materials.

[0057] Method for preparing aqueous dispersions of organosilicon pressure-sensitive adhesive base materials

[0058] The above-mentioned granules can be used in a method for preparing an aqueous dispersion of an organosilicon pressure-sensitive adhesive base. This method includes:

[0059] The method comprising steps 1) to 6) above is used to prepare granules;

[0060] 7) Feed the following starting materials into the dispersion device: the granules prepared in step 6), an additional amount of polydiorganosiloxane resin sufficient to adjust the resin:resin ratio to 0.4:1 to 2:1, a surfactant, and water; and

[0061] 8) The starting materials from step 7) are mixed and heated in the dispersion apparatus to produce the aqueous dispersion of the silicone pressure-sensitive adhesive base material. The method may further include collecting the aqueous dispersion as it exits the dispersion apparatus.

[0062] Step 7) can be performed in conventional continuous process equipment used to prepare aqueous siloxane dispersions. Exemplary examples of continuous mixers / compounders include extruders, such as single-screw extruders, twin-screw extruders, and multi-screw extruders, and co-rotating extruders, such as those manufactured by Krupp Werner & Pfleiderer Corp. (Ramsey, NJ) and Leistritz (NJ); as well as twin-screw counter-rotating extruders, two-stage extruders, twin-rotor continuous mixers, dynamic or static mixers, or combinations of these types of equipment. Alternatively, the dispersing device used in step 7) can be an extruder; alternatively, a twin-screw extruder.

[0063] When an extruder is used in step 7) of the method for preparing an aqueous dispersion of a silicone pressure-sensitive adhesive base material, the extruder can be the same as the extruder used to prepare the granules as described above. Alternatively, a different extruder can be used in step 7) of the method for preparing an aqueous dispersion of a silicone pressure-sensitive adhesive base material. The extruder for preparing an aqueous dispersion of a silicone pressure-sensitive adhesive base material may include a barrel having one or more feed ports spaced apart along the barrel; a screw mechanism housed within the barrel; and optionally an outlet, which is optionally fitted with a back pressure regulator. The screw mechanism is capable of mixing the starting material and conveying the starting material from the feed ports to the outlet. The extruder may also include a heating device configured to heat the barrel. The feed ports are configured to introduce the starting material into the extruder. The extruder may also optionally include a back pressure regulator located at the outlet to control the pressure inside the extruder. Steps 7) and / or 8) can be performed at temperatures from 50°C to 200°C, or alternatively from 70°C to 150°C.

[0064] Other resins

[0065] Additional polydiorganosiloxane resin may be added in step 7) to adjust the resin:resin ratio from the granules to a value suitable for the silicone pressure-sensitive adhesive composition. The additional polydiorganosiloxane resin is as described above, and the selected additional polydiorganosiloxane resin may be the same as or different from the polydiorganosiloxane resin used to prepare the granules. The amount of additional polydiorganosiloxane resin added is sufficient to provide an aqueous dispersion of the silicone pressure-sensitive adhesive base material with a resin:resin ratio of 0.4:1 to 3:1, alternatively 0.4:1 to 2:1, alternatively 0.5:1 to 1.9:1, alternatively 0.7:1 to 1.8:1, alternatively 0.9:1 to 1.7:1, and alternatively 1:1 to 1.5:1.

[0066] surfactants

[0067] Aqueous dispersions of silicone pressure-sensitive adhesive base materials include surfactants. Surfactants can be solid or liquid. Solid surfactants can be delivered as aqueous dispersions containing 25% to 75% solid surfactant (active substance). Surfactants can be fed into the dispersion unit together with the granules. Alternatively, surfactants can be fed into the dispersion unit together with water. Alternatively, surfactants can be fed into the dispersion unit separately from other starting materials. Surfactants are selected from the group consisting of anionic surfactants, nonionic surfactants, and combinations of both anionic and nonionic surfactants, provided that the surfactants do not include sulfonic acids and their salt derivatives, long-chain carboxylic acid surfactants and their salts, fatty acid amines and amides and their salts and derivatives, alkyl glucosides, and linear siloxane polyethers.

[0068] Anionic surfactants include alkyl sulfates having at least six carbon atoms in the alkyl substituent, such as sodium lauryl sulfate; and sulfates of polyoxyethylene monoalkyl ethers. Some other examples of anionic surfactants are: alkali metal sulfosuccinates; sulfonated glycerol esters of fatty acids, such as sulfonated monoglycerides of coconut oil acid; salts of sulfonated monohydric alcohol esters, such as sodium oleoyl isothiosulfate; sulfonated products of fatty acid nitriles, such as palmitonitrile sulfonate; sulfonated aromatic hydrocarbons, such as sodium α-naphthalene monosulfonate; condensation products of naphthalene sulfonic acid and formaldehyde; sodium octahydroanthracene sulfonate; alkali metal alkyl sulfates; ether sulfates having eight or more carbon atoms in the alkyl group, such as sodium lauryl ether sulfate; and alkyl aryl sulfonates having eight or more carbon atoms in one or more alkyl groups.

[0069] Commercially available anionic surfactants include those produced by The Dow Chemical Company of Midland, Michigan, USA, under the trademark DOWFAX. ™ AS-801 is a sodium salt of alkyl alkoxylate sulfates sold by Dow Chemical Company, Midland, Michigan, under the trademark DOWFAX. ™ Sodium hexadecyl diphenyl ether disulfonate sold by 8390; and under the trademark HOSTAPUR by Clariant Corporation, Charlotte, North Carolina. ™ Sodium salts of secondary alkyl sulfonates sold by SAS 60.

[0070] Some suitable nonionic surfactants that can be used include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene fatty acid esters, sorbitol fatty acid esters, and polyoxyethylene sorbitol fatty acid esters. Commercially available nonionic surfactants include compositions, such as (i) those under the name TERGITOL. ™ (ii) 2,6,8-trimethyl-4-nonyl polyoxyethylene ether sold by TMN-10; and (ii) TERGITOL manufactured by Dow Chemical Company, Midland, Michigan, USA. ™ 15-S-9, TERGITOL ™ 15-S-15, TERGITOL ™ 15-S-30 and TERGITOL ™ C11-15 secondary alkyl polyoxyethylene ether sold under the name TRITON by Dow Chemical Company, 15-S-40. ™ (iii) Octylphenyl polyoxyethylene (40) ether sold by X405; and (iii) MAKON by Stepan Company under the name MAKON. ™ (iv) Nonylphenyl polyoxyethylene (10) ether sold by Henkel Corp. / Emery Group, Cincinnati, Ohio, USA under the name Trycol 5953; (v) Ethoxylated alcohol sold by Croda Inc., Edison, New Jersey, USA under the name BRIJ ™ L23 and BRIJ ™ L4 sells ethoxylated alcohols; (vi) alkyl-oxo alcohol polyethylene glycol ethers, such as GENAPOL. ™ UD 050 and GENAPOL ™ UD110; (vii) Alkyl polyethylene glycol ethers based on C10 Guerbert alcohol and ethylene oxides such as LUTENSOLS ™ XP 79.

[0071] Suitable nonionic surfactants also include poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymers. Poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymers are also commonly referred to as poloxamers. Poloxamers are nonionic triblock copolymers composed of a central hydrophobic poly(propylene oxide) chain and two flanking hydrophilic poly(ethylene oxide) chains. Poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymers are commercially available from BASF, Florham Park, New Jersey, USA, and are marketed under the trademark PLURONIC. ™ Such as PLURONIC™ L61, L62, L64, L81, and P84 are for sale.

[0072] Other suitable nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenol ethers, polyoxyethylene lauryl ethers, polyoxyethylene sorbitan monooleate, polyoxyethylene alkyl esters, polyoxyethylene sorbitan alkyl esters, polypropylene glycol, diethylene glycol, ethoxylated trimethylnonanol, and polyoxyalkylene glycol-modified polysiloxane surfactants. Commercially available nonionic surfactants that can be used include compositions, such as those marketed under the trademark TERGITOL. ™ TMN-10 is sold as 2,6,8-trimethyl-4-nonoxyvinyl alcohol; under the trademark TERGITOL. ™ 15-S-7, TERGITOL ™ 15-S-9, TERGITOL ™ 15-S-15 sells alkylene oxide polyvinyl alcohol (C 11-15 Secondary alcohol ethoxylates 7EO, 9EO and 15EO); under the trademark ECOSURF ™ EH-40 and TERGITOL ™ Other C sold under 15-S-12, 15-S-20, 15-S-30 and 15-S-40 11-15 Secondary alcohol ethoxylates; under the trademark TRITON ™ X-405 sells octylphenoxy polyethoxyethanol (40EO); and products under the trademark ECOSURF. ™ EH such as ECOSURF ™ EH-40 is an alcohol ethoxylated form. All of these surfactants are sold by Dow Chemical Company.

[0073] Other useful commercial nonionic surfactants are produced by Stepan Company under the trademark MAKON. ™ 10 Nonylphenoxy polyethoxyethanol (10EO) for sale; by ICI Surfactants, Wilmington, Delaware, USA under the trademark BRIJ ™ 35L commercially available polyoxyethylene 23 lauryl ether (Laureth-23); and RENEX, also sold by ICI Surfactants. ™ 30, a polyoxyethylene ether alcohol.

[0074] Suitable nonionic surfactants also include poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymers. Poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymers are also commonly referred to as poloxamers. Poloxamers are nonionic triblock copolymers composed of a central hydrophobic poly(propylene oxide) chain and two flanking hydrophilic poly(ethylene oxide) chains. Poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymers are commercially available from BASF (Florham Park, NJ) under the trade name PLURONIC. ™ Such as PLURONIC ™ L61, L62, L64, L81, and P84 are for sale.

[0075] Other available commercial nonionic surfactants are those produced by Stepan Company, Northfield, Illinois, under the trade name MAKON. ™ 10. Nonylphenoxy polyethoxyethanol (10EO) sold by ICI Surfactants, Wilmington, Delaware, under the trade name BRIJ. ™ 35L commercially available polyoxyethylene 23 lauryl ether (Laureth-23); and RENEX sold by ICI Surfactants (Wilmington, Delaware). ™ 30 Polyoxyethylene ether alcohol.

[0076] Nonionic surfactants can also be silicone polyethers (SPEs). SPEs can be polysiloxane resins having polyether groups bonded to silicon atoms. Suitable SPEs include DOWSIL from Dow Silicones Corporation of Midland, Michigan, USA. ™ 2-3216 INT.

[0077] Alternatively, nonionic surfactants may include polyvinyl alcohol (PVA) compounds. PVA compounds are known in the art and are disclosed, for example, in paragraphs

[0172] and

[0173] of U.S. Patent Application Publication 20007 / 0099007. PVA compounds can be prepared by saponification of polyvinyl acetate, thus up to 15% polyvinyl acetate can be retained in the PVA compound used herein. Alternatively, the PVA compound may be 88% to 92% PVA (the balance being 12% to 8% polyvinyl acetate). At 20°C, the PVA compound may have a minimum viscosity of 5 cP in a 4% aqueous solution.

[0078] The surfactant used in the methods described herein may be one surfactant or a combination of two or more surfactants. The amount of surfactant depends on various factors, including the type and amount of surfactant selected; however, based on the combined weight of the resin and gum, the amount of surfactant may be sufficient to provide 0.1% to 20%, or alternatively 0.5% to 10%.

[0079] water

[0080] Water is generally unrestricted and can be used in a net form (i.e., without any carrier medium / solvent) and / or a pure form (i.e., free of or substantially free of minerals and / or other impurities). For example, water may be treated or untreated prior to use in the methods described above. Examples of methods that can be used to purify water include distillation, filtration, deionization, and combinations of two or more of these, such that water can be deionized, distilled, and / or filtered. Alternatively, water may be untreated (e.g., tap water supplied by a municipal water supply system, or well water, which can be used without further purification). Alternatively, water may be purified prior to use in the method.

[0081] Water can be used in any amount, which will be selected by those skilled in the art based on various factors, such as the desired dilution of the silicone pressure-sensitive adhesive composition to be prepared. Alternatively, the amount of water in the aqueous dispersion of the silicone pressure-sensitive adhesive base material can be from 10% to 95%, or alternatively from 30% to 70%, based on the combined weight of all starting materials in the aqueous dispersion of the silicone pressure-sensitive adhesive base material.

[0082] Method for preparing aqueous dispersions of organosilicon pressure-sensitive adhesive compositions

[0083] An aqueous dispersion of a silicone pressure-sensitive adhesive base material can be used in a method for preparing an aqueous dispersion of a silicone pressure-sensitive adhesive composition. This method includes: performing steps 1) through 8) above to form an aqueous dispersion of the silicone pressure-sensitive adhesive base material; and 9) mixing the aqueous dispersion of the silicone pressure-sensitive adhesive base material with additional starting materials selected from the group consisting of: free radical initiators, solvents, coating additives, and combinations thereof; thereby forming an aqueous dispersion of the silicone pressure-sensitive adhesive composition. Step 9) can be performed in any convenient manner, using a batch, semi-continuous, or continuous process. The continuous process equipment discussed above with respect to step 7) can be used. Alternatively, the mixing in step 9) can be performed in a batch, semi-continuous, or continuous mode. Batch equipment with high shear and high-speed dispersers can be used, and such batch equipment is commercially available, such as equipment manufactured by Charles Ross & Sons (NY) and Hockmeyer Equipment Corp. (NJ); such as equipment under the trade name Speedmixer. ™ Those batch mixing devices for sale; and batch mixing devices with high shear, such as the Banbury type (CW Brabender Instruments Inc., NJ) and the Henschel type (Henschelmixers America, TX). Alternatively, the mixing in step 9) can be performed, for example, using batch mixing devices with medium / low shear, including change-can mixers, dual planetary mixers, conical screw mixers, bar mixers, sigma-blade mixers, or double-arm or bow-blade mixers. Examples of coating additives include defoamers, wetting agents, pH adjusting additives, and combinations of two or more of them.

[0084] Free radical initiators

[0085] Free radical initiators may include organic peroxide compounds, such as alkyl peroxides, diacyl peroxides, peroxide esters, and / or peroxide carbonates. Suitable organic peroxide compounds include benzoyl peroxide; 4-monochlorobenzoyl peroxide; dicumyl peroxide; tert-butyl peroxybenzoate; tert-butyl peroxide; 2,5-dimethyl-2,5-di-tert-butylperoxyhexane; 2,4-dichlorobenzoyl peroxide; di-tert-butylperoxy-diisopropylbenzene; 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane; 2,5-di-tert-butylperoxyhexane-3,2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane; or isopropylphenyl-tert-butyl peroxide. Suitable peroxide compounds are known in the art and are disclosed, for example, in paragraph

[0093] of U.S. Patent Application Publication 2018 / 0105692.

[0086] The amount of free radical initiator added in step 9) depends on various factors, including the type and amount of the initiator selected and the selection of other starting materials. However, based on the combined weight of the resin and gum, the initiator can be added in amounts of 1% to 10%, alternatively 2% to 6%, and alternatively 2% to 5%.

[0087] solvent

[0088] Solvents may optionally be added to the aqueous dispersion of the silicone pressure-sensitive adhesive composition in steps 7) and / or 9), as described below. It is not desirable to be bound by theory, but it is believed that solvents can facilitate the mixing and / or delivery of one or more starting materials. For example, an initiator may be dissolved or dispersed in a solvent to promote mixing. Suitable solvents include polyalkylsiloxanes and / or organic solvents such as alcohols, ketones, aromatics, aliphatic hydrocarbons, glycol ethers, tetrahydrofurans, mineral oils, naphtha, or combinations thereof. Polyalkylsiloxanes having suitable vapor pressures can be used as solvents, and these polyalkylsiloxanes include hexamethyldisiloxane, octamethyltrisiloxane, hexamethylcyclotrisiloxane, and other low molecular weight polyalkylsiloxanes, such as 0.5 to 1.5 cSt DOWSIL. ™ 200 fluid and DOWSIL ™ OSFLUIDS are commercially available from Dow Silicones in Midland, Michigan, USA.

[0089] Alternatively, organic solvents may be used. Organic solvents may be alcohols, such as methanol, ethanol, isopropanol, butanol, or n-propanol; ketones, such as acetone, methyl ethyl ketone, or methyl isobutyl ketone; aromatic hydrocarbons, such as benzene, toluene, or xylene; aliphatic hydrocarbons, such as heptane, hexane, or octane; glycol ethers, such as propylene glycol methyl ether, dipropylene glycol methyl ether, propylene glycol n-butyl ether, propylene glycol n-propyl ether, or ethylene glycol n-butyl ether, tetrahydrofuran; solvent oils; naphtha; or combinations thereof.

[0090] The amount of solvent will depend on various factors, including the type of solvent chosen and the amount and type of other starting materials selected for the aqueous dispersion of the silicone pressure-sensitive adhesive composition. However, based on the combined weight of all starting materials in the aqueous dispersion of the silicone pressure-sensitive adhesive composition, the amount of solvent can be 0% to <10%, alternatively 0% to <2%, alternatively 0% to <1%, and alternatively 0% to 0.5%. Alternatively, the solvent can be omitted.

[0091] Optional starting materials can also be added to the aqueous dispersion of the silicone pressure-sensitive adhesive composition prepared by the above method. Such optional starting materials include, for example, defoamers, wetting agents, pH adjusting additives, and combinations of two or more thereof. Other optional starting materials include, for example, reactive diluents, fragrances, preservatives, fillers (such as silica, quartz, or chalk), and combinations of two or more thereof.

[0092] Alternatively, the curable silicone pressure-sensitive adhesive composition may be filler-free or contain only a limited amount of filler, such as 0% to 30% by weight of the curable silicone pressure-sensitive adhesive composition. The filler may agglomerate or otherwise adhere to the coating equipment used to apply the curable silicone pressure-sensitive adhesive composition to a substrate. The filler may also impede the optical properties, such as transparency, of the silicone pressure-sensitive adhesive and / or any tape formed therefrom.

[0093] How to use

[0094] The aqueous dispersion of the silicone pressure-sensitive adhesive composition prepared as described above can be used to form adhesive articles, such as silicone pressure-sensitive adhesives (prepared by curing the above-described curable silicone pressure-sensitive adhesive composition), on a substrate. The adhesive article can be prepared by a method comprising: preparing an aqueous dispersion of the silicone pressure-sensitive adhesive composition by performing the above-described method; applying the aqueous dispersion of the silicone pressure-sensitive adhesive composition to the surface of a substrate; and curing the silicone pressure-sensitive adhesive composition to form a silicone pressure-sensitive adhesive. Before curing (and optionally during curing), the substrate can be dried to remove all or part of the water from the aqueous dispersion of the silicone pressure-sensitive adhesive composition, thereby leaving the silicone pressure-sensitive adhesive composition on the substrate.

[0095] To improve the adhesion between the silicone pressure-sensitive adhesive and the substrate, this method may optionally include treating the surface of the substrate before applying an aqueous dispersion of the silicone pressure-sensitive adhesive composition to the substrate. The substrate surface can be treated in any convenient manner, such as applying a primer or subjecting the substrate to corona discharge treatment, etching, or plasma treatment before applying the aqueous dispersion of the silicone pressure-sensitive adhesive composition to the substrate.

[0096] The silicone pressure-sensitive adhesive composition can be applied to the substrate surface by any convenient method. For example, the curable silicone pressure-sensitive adhesive composition can be applied to the substrate surface by a gravure coating machine, offset coating machine, offset gravure coating machine, roller coating machine, reverse roller coating machine, air knife coating machine, or curtain coating machine.

[0097] The substrate can be any material capable of withstanding the curing conditions (described herein) used to cure the silicone pressure-sensitive adhesive composition to form the silicone pressure-sensitive adhesive on the substrate. For example, any substrate capable of withstanding heat treatment at temperatures equal to or greater than 150°C, or alternatively 50°C to 120°C, is suitable. Examples of materials suitable for such substrates include plastic films such as polyimide (PI), polyetheretherketone (PEEK), polyethylene naphthalate (PEN), liquid crystal polyarylate, polyamide-imide (PAI), polyether sulfide (PES), or polyethylene terephthalate (PET), or polyethylene (PE), or polypropylene (PP). Alternatively, the substrate can be a metal foil, such as aluminum foil or copper foil. Alternatively, the substrate can also be paper, such as kraft paper. The thickness of the substrate is not critical; however, thicknesses can range from 5 micrometers to 300 micrometers.

[0098] Drying can be performed before and / or during curing. Drying can be performed by heating at temperatures sufficient to evaporate water (and, when solvents are present), such as 50°C to 120°C, to remove water and cure. Alternatively, drying can be performed by heating at temperatures of 50°C to 120°C, alternatively 50°C to 100°C, and alternatively 70°C to 80°C for a duration sufficient to remove all or part of the water (e.g., 30 seconds to 1 hour, alternatively 1 minute to 5 minutes). The method also includes curing the silicone pressure-sensitive adhesive composition at RT or by heating at temperatures of 80°C to 220°C, alternatively 140°C to 220°C, alternatively 150°C to 220°C, alternatively 160°C to 200°C, and alternatively 165°C to 180°C for a duration sufficient to cure the silicone pressure-sensitive adhesive composition (e.g., 30 seconds to 1 hour, alternatively 1 minute to 5 minutes). If it is necessary to increase the curing speed or reduce the process curing temperature, the initiator level can be increased. This forms a silicone pressure-sensitive adhesive on the substrate. Drying and / or curing can be performed by placing the substrate in an oven. The amount of silicone pressure-sensitive adhesive composition to be applied to the substrate depends on the specific application; however, this amount can be sufficient to result in a silicone pressure-sensitive adhesive thickness of 5 to 200 micrometers after curing.

[0099] The methods described herein may optionally include applying a removable release liner to a silicone pressure-sensitive adhesive opposite to the substrate, for example, to protect the silicone pressure-sensitive adhesive before use of the adhesive article. The release liner may be applied before, during, or after curing the curable silicone pressure-sensitive adhesive composition; alternatively, it may be applied after curing.

[0100] Example

[0101] These examples are intended to illustrate the invention to those skilled in the art and are not to be construed as limiting the scope of the invention as described in the claims. The materials in Table 1 are used in these examples.

[0102] Table 1 - Starting Materials

[0103]

[0104]

[0105] Example 1 - Apparatus and Procedure for Preparing Granules

[0106] Figure 1(A) illustrates an apparatus 110 (method A) for preparing granules. Apparatus 110 includes a twin-screw extruder (Leistritz ZSE27 MAXX, L / D = 48 and 12 stages) 100 upstream of an underwater granulator 108. The twin-screw extruder 100 has a barrel 101 having a first feed port 102, a second feed port 103, and an outlet 104 having a die (not shown); a heating device (not shown) configured to heat the barrel 101; and a screw mechanism (not shown) housed within the barrel 101. The first feed port 102 is configured to introduce resin into a fourth-stage extruder 105. The second feed port 103 is configured to introduce polysilicate resin into a fifth stage 106. The screw mechanism is configured to mix gum and resin from the first feed port 102 and the second feed port 103 and convey it through a die to the outlet 104 to form a filament 107 that enters the underwater pelletizer 108. The underwater pelletizer is configured to cool and pulverize the filament 107 to form pellets that exit the extruder at the outlet 109.

[0107] All or part of the resin is fed into the extruder 100 through the first feed port 102. All the resin is fed into the extruder 100 through the second feed port 103. For some samples, a portion of the resin is added through the first feed port 102, and the remainder is added together with the resin through the second feed port 103. The barrel is heated to 200°C to 250°C. The resin added through the first feed port 102 is fed at a rate of 2.5 kg / h, and the resin added through the second feed port 103 (optionally including a portion of the resin) is fed at a rate of 7.5 kg / h. The resin and resin are mixed and conveyed through a die (not shown) to the outlet 104 to form a filament 107. The filament enters an underwater granulator 108 and is pulverized into granules, which exit the apparatus 110 at the outlet 109. Table 2 below shows formulations of resin and resin used to form granules using this general procedure.

[0108] Table 2 below shows the composition of the granules prepared using the procedure of Reference Example 1. The types of resins and gums are as defined in Table 1. The amounts of resins and gums are in parts by weight.

[0109] Table 2 - Composition of Granular Materials

[0110]

[0111] Comparative Example 2

[0112] Figure 1(B) illustrates an apparatus 210 (Method B) for preparing granules. Apparatus 210 includes a twin-screw extruder (Leistritz ZSE27 MAXX, L / D = 48 and 12 stages) 200 upstream of an underwater granulator 208. The twin-screw extruder 200 has a barrel 201 with a first feed port 203, a second feed port 202, and an outlet 204 with a die (not shown); a heating device (not shown) configured to heat the barrel 201; and a screw mechanism (not shown) housed within the barrel 201. The first feed port 203 is configured to introduce resin into a fourth-stage extruder 206. The second feed port 202 is configured to introduce gum into a fourth stage 205. The screw mechanism is configured to mix resin and gum from the first feed port 203 and the second feed port 202 and convey it through a die to the outlet 204 to form a filament 207 that enters the underwater pelletizer 208. The underwater pelletizer is configured to cool and pulverize the filament 207 to form pellets that exit the extruder at the outlet 209.

[0113] All resin is fed into extruder 200 through first feed port 203. All or part of the resin is fed into extruder 200 through second feed port 202. For some samples, a portion of the resin is added together with the resin through first feed port 203, and the remainder is added through second feed port 202. The barrel is heated to 200°C to 250°C. The resin added through second feed port 202 is fed at 2.5 kg / h, and the resin added through first feed port 203 (optionally including a portion of the resin) is fed at 7.5 kg / h. The resin and resin are mixed and conveyed through a die (not shown) to outlet 204 to form filament 207. The filament enters underwater granulator 208 and is pulverized into granules, which exit device 210 at outlet 209. Composition 1 from Table 2 above is used.

[0114] Figure 2 (A) shows granules prepared using composition number 1 in Table 2 by the method of Example 1. Figure 2 (B) shows granules prepared using composition 1 in Table 2 by the method of Comparative Example 2. The granules prepared by the method of Comparative Example 2 are non-uniform in size, shape, and appearance. It is not intended to be theoretically rigorous, but it is believed that Example 1 and Comparative Example 2 demonstrate that the order of addition (i.e., adding at least 85% of the resin before adding the resin) provides benefit to the methods of granule preparation described herein, namely, that, using the claimed method, the granules have more uniform size and shape and an improved appearance.

[0115] Example 3

[0116] Figure 1(C) illustrates an apparatus 310 (method C) for preparing granules. Apparatus 310 includes a twin-screw extruder (Leistritz ZSE27 MAXX, L / D = 48 and 12 stages) 300 upstream of a water tank 311, the water tank being located upstream of a granulator 308. The twin-screw extruder 300 has a barrel 301 having a first feed port 302, a second feed port 303, and an outlet 304 having a die (not shown); a heating device (not shown) configured to heat the barrel 301; and a screw mechanism (not shown) housed within the barrel 301. The first feed port 302 is configured to introduce resin into a fourth-stage extruder 305. The second feed port 303 is configured to introduce polysilicate resin into a fifth stage 306. The screw mechanism is configured to mix gum and resin from the first feed port 302 and the second feed port 303 and convey it through a die to the outlet 304 to form filament 307, which enters a water tank 311 and then enters an underwater pelletizer 308. The underwater pelletizer 308 is configured to cool and pulverize the filament 307 to form pellets that exit the extruder at the outlet 309.

[0117] All or part of the resin is fed into the extruder 300 through the first feed port 302. All the resin is fed into the extruder 300 through the second feed port 303. For some samples, a portion of the resin is added through the first feed port 302, and the remainder is added together with the resin through the second feed port 303. The barrel is heated to 200°C to 250°C. The resin added through the first feed port 302 is fed at 2.5 kg / h, and the resin added through the second feed port 303 (optionally including a portion of the resin) is fed at 7.5 kg / h. The resin and resin are mixed and conveyed through a die (not shown) to the outlet 304 to form a filament 307. The filament enters an underwater granulator 308 and is pulverized into granules, which exit the device 310 at the outlet 309. As in Example 1 and Comparative Example 2, Composition 1 from Table 2 above is used to prepare the granules. The granules are described below. Figure 2 As shown in (C). Example 3 demonstrates that, as long as the order of addition of the gum and resin is used, granules of acceptable quality can be prepared using the methods described herein with different granulation equipment.

[0118] The silicone pressure-sensitive adhesive was prepared using the granules prepared according to the method in Example 1 using composition number 4 and composition number 3 in Table 2 above.

[0119] Example 4

[0120] Using the starting materials shown in Table 3, prepare additional granules using the method of Example 1. Feed resin 4 into the first port of the extruder and feed resin or a blend of resin and resin into the second port.

[0121] Table 3 - Composition of Granular Materials

[0122]

[0123] Example 5

[0124] An aqueous dispersion of an organosilicon pressure-sensitive adhesive base material is prepared as follows.

[0125] The granules prepared as described in Example 4 are fed through a loss-in-weight screw feeder into the first barrel of a 25 mm twin-screw extruder (Coperion ZSK26, L / D = 48 and 12 stages), followed by resin feeding through a gear pump into the second or third barrel. Surfactant is injected with 5% to 25% (by weight of silicone solids, i.e., the combination of resin and resin) of water into the fourth (or fifth or sixth) barrel using a piston pump (ISCO 1000D). The remaining water is injected into more downstream barrels (e.g., the eighth to twelfth). All barrels are set to 80°C to 120°C, and the extruder is operated at 300 RPM to 900 RPM. The aqueous dispersion of the silicone pressure-sensitive adhesive base material is collected at the extruder outlet.

[0126] The amount of each starting material is shown in Table 4 below.

[0127] Table 4 - Composition of aqueous dispersions of silicone pressure-sensitive adhesive base materials

[0128]

[0129] Example 6

[0130] The aqueous dispersion of the silicone pressure-sensitive adhesive composition is prepared as follows:

[0131] 10 grams of the prepared dispersion and a certain weight of initiator (PERKADOX) were added. ™ L-40 RPS (Noryon) and optionally some additives are added directly together and processed by SpeedMixer. ™ Mix at 2000 RPM for 1 minute.

[0132] The amount of each starting material is shown in Table 5 below.

[0133] Table 5 - Composition of aqueous dispersions of silicone pressure-sensitive adhesive compositions

[0134]

[0135] In Inv8, the pH was adjusted from 7.6 to 11.2 using KOH.

[0136] Example 7

[0137] The adhesion of the sample prepared in Example 6 to SUS was tested according to the following test method. The results are given in Table 6.

[0138] Table 6 - PSA performance on PET film

[0139]

[0140] The testing methods used in this article include the following:

[0141] Particle size was measured using a Beckman Coulter LS230 laser diffraction particle size analyzer.

[0142] Adhesion to stainless steel (SUS) was tested according to the following procedure. An aqueous dispersion of the silicone pressure-sensitive adhesive composition was pulled down onto two PET substrates using a four-bird stick. The coated substrates were heated at 80°C for 2 minutes and then at 180°C for 3 minutes. The coated substrates were then cooled and cut into 1-inch wide strips. The 1-inch strips were applied to a clean stainless steel panel / glass. The samples were tested the following day by pulling them at 180° and 12 inches / minute on a TMI peel and adhesion tester. Units are grams per inch (g / inch).

[0143] The weight-average molecular weight and number-average molecular weight of the starting materials, including the above-mentioned gums and resins, can be measured by gel permeation chromatography (GPC) according to the test method in Reference Example 1, beginning in column 31 of U.S. Patent 9,593,209.

[0144] Industrial applicability

[0145] The examples above demonstrate that silicone pressure-sensitive adhesives with good adhesion to stainless steel can be prepared using the methods described herein. Inv7 and Inv8 show that the samples may include additives (equivalent to Inv2 and Inv3, respectively), and these additives can improve adhesion.

[0146] Definition and use of terms

[0147] Unless the context otherwise indicates, all quantities, ratios, and percentages herein are by weight; the articles “an,” “a,” and “the” each mean one (a kind) or a plurality (multiples); and the singular includes the plural. The summary of the invention and the abstract of the specification are incorporated herein by reference. The transitional phrases “comprising,” “consisting essentially of,” and “consisting of” are used as described in Chapters 2111.03 I, II, and III of the Patent Examining Procedure Ninth Edition, last revised January 2018, Amendment 08.2017. The use of “for example,” “for instance,” “such as,” and “including” to list exemplary examples does not imply limitation to the listed examples. Therefore, “for example” or “such as” means “for example, but not limited to” or “such as, but not limited to” and covers other similar or equivalent examples. DOWSIL ™ SILASTIC ™ and SYL-OFF ™ The branded materials are commercially available from Dow Silicones, Midland, Michigan, USA. The abbreviations used herein have their definitions in Table 8.

[0148] Table 8 - Abbreviations

[0149]

[0150] Embodiments of the present invention

[0151] In a first embodiment, a method for preparing an aqueous dispersion of an organosilicon pressure-sensitive adhesive base material from solvent-free polyorganosiloxane granules includes:

[0152] 1) An extruder is provided, the extruder including a barrel having a first feed port, a second feed port, and an outlet having a die; a heating device configured to heat the barrel; and a screw mechanism housed within the barrel, wherein the first feed port and the second feed port are configured to introduce starting material into the extruder, the screw mechanism being capable of mixing the starting material from the first feed port and the second feed port and conveying the starting material to the outlet, the first feed port being located upstream of the second feed port, and the second feed port being located upstream of the outlet;

[0153] 2) At least a portion of i) solvent-free polydiorganosiloxane resin is added to the extruder through the first feed port, and ii) solvent-free polyorganosilicate resin is added to the extruder through the second feed port, wherein the resin and the resin are added in a certain amount such that the weight ratio of resin to resin is 2.1:1 to 5:1.

[0154] 3) The solvent-free polydiorganosiloxane resin and the solvent-free polyorganosilicate resin are mixed in the barrel, and the barrel is heated to a temperature of 200°C to 250°C to form a mixture;

[0155] 4) The mixture is conveyed through the mold at the outlet to form a wire;

[0156] 5) Cool the wire material leaving the mold, and

[0157] 6) Crush the wire material to prepare the solvent-free polyorganosiloxane granules;

[0158] 7) Feed the starting material comprising the following into the dispersing apparatus: the granules prepared in step 6); a surfactant selected from the group consisting of anionic surfactants, nonionic surfactants, and combinations thereof; and water; and optionally additional polydiorganosiloxane resin, the amount of which is sufficient to adjust the resin:resin ratio to 0.4:1 to 3:1; provided that the surfactant does not contain sulfonic acids and their salt derivatives, long-chain carboxylic acid surfactants and their salts, fatty acid amines and amides and their salts and derivatives, alkyl glucosides, and linear organosilicon polyethers; and

[0159] 8) The starting material from step 7) is mixed and heated in the dispersion apparatus to produce the aqueous dispersion of the silicone pressure-sensitive adhesive base.

[0160] In a second embodiment, the method according to the first embodiment further includes: preparing a solvent-based polyorganosilicate resin prior to step 2) and removing volatile substances from the solvent-based polyorganosilicate resin to form the solvent-free polyorganosilicate resin.

[0161] In a third embodiment, in the method according to the first or second embodiment, the solvent-free polyorganosilicate resin comprises a unitary formula (R... 1 R 2 2SiO 1 / 2 ) w (R 2 3SiO 1 / 2 ) x (SiO 4 / 2) y X z , where each R 2 Independently selected from the group consisting of alkyl groups having 1 to 18 carbon atoms and aryl groups having 6 to 18 carbon atoms; each R 2 It is an independently selected alkenyl group having 2 to 18 carbon atoms; X represents a hydrolyzable substituent; subscript w ≥ 0, subscript x > 4, subscript y > 1, subscript z ≥ 0, provided that the amount (w + x + y + z) is sufficient to make the number average molecular weight of the resin from 2,000 g / mol to 15,000 g / mol.

[0162] In the fourth embodiment, in the method according to any one of the first to third embodiments, the solvent-free polydiorganosiloxane resin comprises a unitary formula (R... 3 R 2 2SiO 1 / 2 ) a (R 2 2SiO 2 / 2 ) b (R 2 SiO 3 / 2 ) c , where each R 2 Independently selected from the group consisting of alkyl groups having 1 to 18 carbon atoms and aryl groups having 6 to 18 carbon atoms, and each R 3 It is a curable group, with subscript a ≥ 2, subscript b > 5000, and subscript c ≥ 0, provided that the amount (a + b + c) is sufficient to provide the resin with a number average molecular weight of 150,000 g / mol to 1,000,000 g / mol.

[0163] In the fifth embodiment, in the method according to any one of the first to fourth embodiments, all of the resin is added to the first feed inlet.

[0164] In the sixth embodiment, in the method according to any one of the first to fifth embodiments, 0 to 15% of the resin is added to the second feed inlet.

[0165] In the seventh embodiment, in the method according to any one of the first to sixth embodiments, steps 5) and 6) are performed using an underwater granulator.

[0166] In the eighth embodiment, in the method according to any one of the first to seventh embodiments, the dispersing device in step 7) is an additional extruder.

[0167] In a ninth embodiment, a method for preparing an aqueous dispersion of an organosilicon pressure-sensitive adhesive composition includes:

[0168] 1) An extruder is provided, the extruder including a barrel having a first feed port, a second feed port, and an outlet having a die; a heating device configured to heat the barrel; and a screw mechanism housed within the barrel, wherein the first feed port and the second feed port are configured to introduce starting material into the extruder, the screw mechanism being capable of mixing the starting material from the first feed port and the second feed port and conveying the starting material to the outlet, the first feed port being located upstream of the second feed port, and the second feed port being located upstream of the outlet;

[0169] 2) At least a portion of i) solvent-free polydiorganosiloxane resin is added to the extruder through the first feed port, and ii) solvent-free polyorganosilicate resin is added to the extruder through the second feed port, wherein the resin and the resin are added in a certain amount such that the weight ratio of resin to resin is 2.1:1 to 5:1.

[0170] 3) The solvent-free polydiorganosiloxane resin and the solvent-free polyorganosilicate resin are mixed in the barrel, and the barrel is heated to a temperature of 200°C to 250°C to form a mixture;

[0171] 4) The mixture is conveyed through the mold at the outlet to form a wire;

[0172] 5) Cool the wire material leaving the mold;

[0173] 6) Crush the wire material to prepare the solvent-free polyorganosiloxane granules;

[0174] 7) Feed the starting material comprising the following into the dispersion device: the granules prepared in step 6); a surfactant selected from the group consisting of anionic surfactants, nonionic surfactants, and combinations thereof; and water; and optionally additional polydiorganosiloxane resin, the amount of which is sufficient to adjust the resin:resin ratio to 0.4:1 to 2:1, provided that the surfactant does not contain sulfonic acids and their salt derivatives, long-chain carboxylic acid surfactants and their salts, fatty acid amines and amides and their salts and derivatives, alkyl glucosides, and linear organosilicon polyethers; and

[0175] 8) The starting material from step 7) is mixed and heated in the dispersion apparatus to produce the aqueous dispersion of the silicone pressure-sensitive adhesive base; and

[0176] 9) Adding additional starting materials to the aqueous dispersion of the silicone pressure-sensitive adhesive base, wherein the additional starting materials are selected from the group consisting of free radical initiators, solvents, coating additives and combinations thereof; thereby forming the aqueous dispersion of the silicone pressure-sensitive adhesive composition.

[0177] In the tenth embodiment, the coating additive is present in the method according to the ninth embodiment, and the coating additive is selected from the group consisting of defoamers, wetting agents and pH adjusting additives.

[0178] In the eleventh embodiment, a method for preparing an adhesive article includes:

[0179] 11. A method for preparing an adhesive article, the method comprising:

[0180] 1) An extruder is provided, the extruder including a barrel having a first feed port, a second feed port, and an outlet having a die; a heating device configured to heat the barrel; and a screw mechanism housed within the barrel, wherein the first feed port and the second feed port are configured to introduce starting material into the extruder, the screw mechanism being capable of mixing the starting material from the first feed port and the second feed port and conveying the starting material to the outlet, the first feed port being located upstream of the second feed port, and the second feed port being located upstream of the outlet;

[0181] 2) At least a portion of i) solvent-free polydiorganosiloxane resin is added to the extruder through the first feed port, and ii) solvent-free polyorganosilicate resin is added to the extruder through the second feed port, wherein the resin and the resin are added in a certain amount such that the weight ratio of resin to resin is 2.1:1 to 5:1.

[0182] 3) The solvent-free polydiorganosiloxane resin and the solvent-free polyorganosilicate resin are mixed in the barrel, and the barrel is heated to a temperature of 200°C to 250°C to form a mixture;

[0183] 4) The mixture is conveyed through the mold at the outlet to form a wire;

[0184] 5) Cool the wire material leaving the mold;

[0185] 6) Crush the wire material to prepare the solvent-free polyorganosiloxane granules;

[0186] 7) Feed the starting material comprising the following into the dispersion apparatus: the granules prepared in step 6); a surfactant, wherein the surfactant does not include sulfonic acids and their salt derivatives, long-chain carboxylic acid surfactants and their salts, quaternary ammonium salts, fatty acid amines and amides and their salts and derivatives, betaine, alkyl glucosides and linear organosilicon polyethers; and water; and optionally additional polydiorganosiloxane resin, the amount of which is sufficient to adjust the resin:resin ratio to 0.4:1 to 2:1; and

[0187] 8) The starting material from step 7) is mixed and heated in the dispersion apparatus to produce the aqueous dispersion of the silicone pressure-sensitive adhesive base; and

[0188] 9) Adding additional starting materials to the aqueous dispersion of the silicone pressure-sensitive adhesive base, wherein the additional starting materials are selected from the group consisting of free radical initiators, solvents, coating additives and combinations thereof; thereby forming the aqueous dispersion of the silicone pressure-sensitive adhesive composition;

[0189] Optionally 10) Treat the surface of the substrate;

[0190] 11) Apply the aqueous dispersion of the silicone pressure-sensitive adhesive composition to the surface of the substrate.

[0191] Optionally 12) removing all or part of the water and solvent (if present) to form the pressure-sensitive adhesive composition layer on the surface of the substrate, and

[0192] 13) Curing the silicone pressure-sensitive adhesive composition to form a silicone pressure-sensitive adhesive.

Claims

1. A method for preparing an aqueous dispersion of an organosilicon pressure-sensitive adhesive base material from solvent-free polyorganosiloxane granules, the method comprising: 1) Provide an extruder, the extruder including a barrel having a first feed port, a second feed port and an outlet having a die; A heating device configured to heat the barrel; and a screw mechanism housed within the barrel, wherein a first feed port and a second feed port are configured to introduce starting material into the extruder, the screw mechanism being capable of mixing the starting material from the first feed port and the second feed port and conveying the starting material to the outlet, the first feed port being located upstream of the second feed port and the second feed port being located upstream of the outlet; 2) At least a portion of i) solvent-free polydiorganosiloxane resin is added to the extruder through the first feed port, and ii) solvent-free polyorganosilicate resin is added to the extruder through the second feed port, wherein the resin and the resin are added in a certain amount such that the weight ratio of resin to resin is 2.1:1 to 5:

1. 3) The solvent-free polydiorganosiloxane resin and the solvent-free polyorganosilicate resin are mixed in the barrel, and the barrel is heated to a temperature of 200°C to 250°C to form a mixture; 4) The mixture is conveyed through the mold at the outlet to form a wire; 5) Cool the wire material leaving the mold, and 6) Crush the wire material to prepare the solvent-free polyorganosiloxane granules; 7) Feed the starting material comprising the following into the dispersing apparatus: the granules prepared in step 6); optionally additional polydiorganosiloxane resin, the amount of which is sufficient to adjust the resin:resin ratio to 0.4:1 to 3:1; a surfactant selected from the group consisting of anionic surfactants, nonionic surfactants, and combinations thereof; and water; provided that the surfactant does not contain sulfonic acids and their salt derivatives, long-chain carboxylic acid surfactants and their salts, fatty acid amines and amides and their salts and derivatives, alkyl glucosides, and linear organosilicon polyethers; and 8) The starting material from step 7) is mixed and heated in the dispersion apparatus to produce the aqueous dispersion of the silicone pressure-sensitive adhesive base.

2. The method according to claim 1, further comprising: Before step 2), a solvent-based polyorganosilicate resin is prepared and volatile substances are removed from the solvent-based polyorganosilicate resin to form the solvent-free polyorganosilicate resin.

3. The method according to claim 1, wherein the solvent-free polyorganosilicate resin comprises a unitary formula (R... 1 R 2 2SiO 1 / 2 ) w (R 2 3SiO 1 / 2 ) x (SiO 4 / 2 ) y X z , where each R 2 Independently selected from the group consisting of alkyl groups having 1 to 18 carbon atoms and aryl groups having 6 to 18 carbon atoms; each R 1 It is an independently selected alkenyl group having 2 to 18 carbon atoms; X represents a hydrolyzable substituent; subscript w ≥ 0, subscript x > 4, subscript y > 1, subscript z ≥ 0, provided that the amount (w + x + y + z) is sufficient to make the number average molecular weight of the resin from 2,000 g / mol to 15,000 g / mol.

4. The method according to claim 1, wherein the solvent-free polydiorganosiloxane resin comprises a unitary formula (R... 3 R 2 2SiO 1 / 2 ) a (R 2 2SiO 2 / 2 ) b (R 2 SiO 3 / 2 ) c , where each R 2 Independently selected from the group consisting of alkyl groups having 1 to 18 carbon atoms and aryl groups having 6 to 18 carbon atoms, and each R 3 It is a curable group, with subscript a ≥ 2, subscript b > 5000, and subscript c ≥ 0, provided that the amount (a + b + c) is sufficient to provide the resin with a number average molecular weight of 150,000 g / mol to 1,000,000 g / mol.

5. The method of claim 1, wherein all of the resin is added to the first feed inlet.

6. The method of claim 1, wherein 0 to 15% of the resin is added to the second feed inlet.

7. The method according to claim 1, wherein steps 5) and 6) are performed using an underwater granulator.

8. The method of claim 1, wherein the dispersing device in step 7) is an additional extruder.

9. A method for preparing an aqueous dispersion of an organosilicon pressure-sensitive adhesive composition, wherein the method comprises: I) Implementing the method according to any one of claims 1 to 8 to form the aqueous dispersion of the organosilicon pressure-sensitive adhesive base, and II) Adding additional starting materials to the aqueous dispersion of the silicone pressure-sensitive adhesive base, wherein the additional starting materials are selected from the group consisting of free radical initiators, solvents, coating additives and combinations thereof; thereby forming the aqueous dispersion of the silicone pressure-sensitive adhesive composition.

10. The method of claim 9, wherein the coating additive is present, and the coating additive is selected from the group consisting of defoamers, wetting agents and pH adjusting additives.

11. A method for preparing an adhesive article, the method comprising: Optionally 1) Treat the surface of the substrate; 2) Perform the method according to claim 9 to form the aqueous dispersion of the silicone pressure-sensitive adhesive composition, and apply the aqueous dispersion of the silicone pressure-sensitive adhesive composition to the surface of the substrate. Optionally 3) Remove all or part of the water and the solvent, if the solvent is present, to form the pressure-sensitive adhesive composition layer on the surface of the substrate, and 4) Curing the silicone pressure-sensitive adhesive composition to form a silicone pressure-sensitive adhesive.

12. A method for preparing solvent-free polyorganosiloxane granules, the method comprising: 1) Provide an extruder, the extruder including a barrel having a first feed port, a second feed port and an outlet having a die; A heating device configured to heat the barrel; and a screw mechanism housed within the barrel, wherein a first feed port and a second feed port are configured to introduce starting material into the extruder, the screw mechanism being capable of mixing the starting material from the first feed port and the second feed port and conveying the starting material to the outlet, the first feed port being located upstream of the second feed port and the second feed port being located upstream of the outlet; 2) At least a portion of i) solvent-free polydiorganosiloxane resin is added to the extruder through the first feed port, and ii) solvent-free polyorganosilicate resin is added to the extruder through the second feed port, wherein the resin and the resin are added in a certain amount such that the weight ratio of resin to resin is 2.1:1 to 5:

1. 3) The solvent-free polydiorganosiloxane resin and the solvent-free polyorganosilicate resin are mixed in the barrel, and the barrel is heated to a temperature of 200°C to 250°C to form a mixture; 4) The mixture is conveyed through the mold at the outlet to form a wire; 5) Cool the wire material leaving the mold, and 6) Crush the wire material to prepare the solvent-free polyorganosiloxane granules.

13. The method of claim 12, wherein the solvent-free polyorganosilicate resin comprises a unitary formula (R... 1 R 2 2SiO 1 / 2 ) w (R 2 3SiO 1 / 2 ) x (SiO 4 / 2 ) y X z , where each R 2 Independently selected from the group consisting of alkyl groups having 1 to 18 carbon atoms and aryl groups having 6 to 18 carbon atoms; each R 1 It is an independently selected alkenyl group having 2 to 18 carbon atoms; X represents a hydrolyzable substituent; subscript w ≥ 0, subscript x > 4, subscript y > 1, subscript z ≥ 0, provided that the amount (w + x + y + z) is sufficient to make the number average molecular weight of the resin from 2,000 g / mol to 15,000 g / mol.

14. The method of claim 12, wherein the solvent-free polydiorganosiloxane resin comprises a unitary formula (R... 3 R 2 2SiO 1 / 2 ) a (R 2 2SiO 2 / 2 ) b (R 2 SiO 3 / 2 ) c , where each R 2 Independently selected from the group consisting of alkyl groups having 1 to 18 carbon atoms and aryl groups having 6 to 18 carbon atoms, and each R 3 It is a curable group, with subscript a ≥ 2, subscript b > 5000, and subscript c ≥ 0, provided that the amount (a + b + c) is sufficient to provide the resin with a number average molecular weight of 150,000 g / mol to 1,000,000 g / mol.

15. The method of claim 14, wherein the weight ratio of resin to gum is 2.1:1 to 3.5:1.

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