Solvent-free pressure-sensitive adhesive composition

Abstract

The process for preparing the solventless pressure-sensitive adhesive composition includes mixing (A) a solid polyorganosilicate resin component with (B) an aliphatic unsaturated polydiorganosiloxane (B-1), a branched polyorganosiloxane (B-2), or a mixture of (B-1) and (B-2) at a specific temperature, followed by cooling. The solventless pressure-sensitive adhesive composition prepared by this process has low viscosity and can be cured to form a pressure-sensitive adhesive. The pressure-sensitive adhesive is suitable for protective film applications.

Description

Technical Field

[0001] The present invention relates to a solvent-free pressure-sensitive adhesive composition and a process for preparing the pressure-sensitive adhesive composition.

Background Art

[0002] Introduction Polyorganosilicate resins are solids at room temperature. Without a solvent, polyorganosilicate resins typically have the form of powders or flakes, making it difficult to mix homogeneously with other components when preparing silicone pressure-sensitive adhesive (PSA) compositions. Attempts to prepare solvent-free PSA compositions typically involve dissolving the polyorganosilicate resin in a solvent or combining the polyorganosilicate resin and other silicone components in a solvent and then removing the solvent. The step of solvent removal (e.g., stripping) increases manufacturing and equipment costs, and the resulting composition typically contains residual solvents in amounts exceeding 1,000 ppm (parts per million). Further, for certain applications such as protective films, a relatively low viscosity, e.g., less than 5000 millipascal seconds (mPa·s) at room temperature, is desirable. However, commercially available solvent-free PSA compositions usually have a high viscosity, making it difficult to directly coat such solvent-free PSA compositions onto a substrate. In this case, customers still need to dilute the PSA composition with a solvent after receiving the PSA composition and before use.

[0003] It is desirable to discover a process for preparing a solvent-free PSA composition suitable for use in protective films for electronics applications that does not cause the aforementioned problems.

Summary of the Invention

[0004] The present invention solves the problem of discovering a solvent-free pressure-sensitive adhesive (PSA) composition that does not cause the aforementioned problems.

[0005] The present invention provides a novel process for preparing a solventless PSA composition, which process comprises preparing a silicone-based moiety having a viscosity of less than 5000 millipascal seconds (mPa·s) at room temperature. The resulting solventless PSA composition of the present invention can be applied directly to a substrate and can be cured to form a pressure-sensitive adhesive (PSA). The PSA can provide a desired coating appearance and adhesion strength particularly suitable for protective film applications, for example, a peel adhesion force of 20 grams per inch (g / in) or less. The viscosity and adhesion properties can be measured according to the test methods described in the following Examples section.

[0006] In a first aspect, the present invention provides a process for preparing a solventless pressure-sensitive adhesive composition. The process comprises (i) providing a starting material (A) a solid polyorganosilicate resin component, wherein the solid polyorganosilicate resin component comprises (A-1) a solid capped resin of unit formula (I-1) of more than 30% by weight to 100% by weight based on the weight of the starting material (A), (R M 3SiO 1 / 2 ) a (SiO 4 / 2 ) b Z c (wherein each R M is independently a monovalent hydrocarbon group of 1 to 20 carbon atoms, each Z is independently a hydrolyzable group selected from the group consisting of alkoxy, hydroxyl, or mixtures thereof, c is from 0 to a value sufficient such that the hydrolyzable group content of the capped resin is at most 2% by weight based on the weight of the capped resin, a and b have values such that a > 4, b > 0, and the value of (a + b) is sufficient for the number average molecular weight of the capped resin to be 500 to 8,000 g / mol) and (A-2) a solid uncapped resin of unit formula (I-2) of 0 to less than 70% by weight based on the weight of the starting material (A), (R M 3SiO 1 / 2 ) a’ (SiO 4 / 2 )b’ Z c’ (wherein R M and Z are as defined above, a' and b' have values such that a' > 4 and b' > 0, and the value of (a' + b') is sufficient for the number average molecular weight of the uncapped resin to be 500 to 8,000 g / mol, and c' has a value sufficient for the hydrolyzable group content of the uncapped resin to be more than 2% by weight to 10% by weight based on the weight of the uncapped resin), and, a step comprising: (ii) A step of mixing starting material (A) with starting material (B) and optionally starting material (C) at a temperature of 100°C or higher, wherein starting material (B) is an aliphatic unsaturated polydiorganosiloxane (B-1), a branched polyorganosiloxane (B-2), or a mixture of (B-1) and (B-2), the aliphatic unsaturated polydiorganosiloxane (B-1) has the unit formula (II-1), (R 1 2R 2 SiO 1 / 2 ) x (R 1 3SiO 1 / 2 ) y (R 1 R 2 SiO 2 / 2 ) z (R 1 2SiO 2 / 2 ) w (wherein each R 1 is independently a monovalent hydrocarbon group having 1 to 20 carbon atoms and containing no aliphatic unsaturation, and each R 2 is independently a monovalent aliphatic unsaturated hydrocarbon group having 2 to 20 carbon atoms, and x, y, z, and w have values such that x > 0, y ≧ 0, (x + y) = 2, z ≧ 0, w ≧ 0, and (w + z) > 0, and the value of (x + y + z + w) is sufficient for the number average molecular weight of the aliphatic unsaturated polydiorganosiloxane to be 5,000 to 50,000 g / mol), the branched polyorganosiloxane (B-2) has the unit formula (II-2), (R 1 3SiO 1 / 2 ) g(R 1 2R 2 SiO 1 / 2 ) h (R 1 2SiO 2 / 2 ) i (SiO 4 / 2 ) (wherein R 1 and R 2 are as described above, g, h, and i have values such that 2 ≥ g ≥ 0, 4 ≥ h ≥ 0, 995 ≥ i ≥ 4, and (g + h) = 4, and the value of (g + h + i) is sufficient for the number average molecular weight of the branched polyorganosiloxane to be 5,000 to 50,000 g / mol) and starting material (C) is a polydiorganosiloxane gum of unit formula (III), (R 1 2R G SiO 1 / 2 )2(R 1 2SiO 2 / 2 ) d (wherein R 1 is as described above, and each R G is independently a monovalent aliphatic unsaturated hydrocarbon group having 2 to 20 carbon atoms, hydroxyl, or a combination thereof, and d has a value sufficient for the number average molecular weight of the polydiorganosiloxane gum to be 300,000 g / mol or more) and starting materials (A), (B), and (C) are present in amounts such that the weight ratio of the amount of starting material (A) to the total amount of starting materials (B) and (C) (when present) is 0.1 to 1.2, a step, (iii) cooling the mixture obtained in step (ii) to form a silicone-based moiety having a viscosity of less than 5,000 mPa·s at room temperature, a step, (iv) mixing the silicone-based moiety obtained in step (iii) with starting material (D) polyorganohydrogensiloxane, starting material (E) hydrosilylation reaction catalyst, optionally starting material (F) hydrosilylation reaction inhibitor, and optionally starting material (G) fixing additive, thereby forming a solventless pressure-sensitive adhesive composition), including.

[0007] In a second aspect, the present invention provides a solvent-free pressure-sensitive adhesive composition prepared by the process of the first aspect.

[0008] In a third aspect, the present invention provides a method for manufacturing an adhered article, the manufacturing method comprising: optionally, (1) a step of treating the surface of a substrate; (2) a step of coating the surface of the substrate with the solvent-free pressure-sensitive adhesive composition of the second aspect; (3) a step of curing the solvent-free pressure-sensitive adhesive composition.

MODE FOR CARRYING OUT THE INVENTION

[0009] "Solid" means that the resin or polymer is solid at room temperature (23 ± 2 degrees Celsius (°C)).

[0010] As used herein, "alkyl" means a cyclic, branched or unbranched saturated monovalent hydrocarbon group. Examples of alkyl groups include 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, decyl, branched alkyl groups having 6 or more carbon atoms, and cyclic alkyl groups such as cyclopentyl and cyclohexyl.

[0011] As used herein, "aryl" means a cyclic, completely unsaturated hydrocarbon group. Examples of aryl include, but are not limited to, cyclopentadienyl, phenyl, anthracenyl, and naphthyl. The monocyclic aryl group may have 5 to 9 carbon atoms, 6 to 7 carbon atoms, or 5 to 6 carbon atoms. The polycyclic aryl group may have 10 to 17 carbon atoms, 10 to 14 carbon atoms, or 12 to 14 carbon atoms.

[0012] As used herein, "aralkyl" means an alkyl group having a pendant and / or terminal aryl group, or an aryl group having a pendant alkyl group. Exemplary aralkyl groups include tolyl, xylyl, benzyl, phenylethyl, phenylpropyl, and phenylbutyl.

[0013] As used herein, "alkenyl" means a branched or unbranched monovalent hydrocarbon group having one or more carbon-carbon double bonds.

[0014] The process for preparing the solvent-free PSA composition of the present invention includes the step of (i) providing starting material (A), starting material (B), and optionally starting material (C). The starting material (A) useful in the present invention is a solid polyorganosilicate resin component comprising, based on the weight of the starting material (A), more than 30% by weight to 100% by weight of a solid capped resin (A-1) and 0 to less than 70% by weight of a solid uncapped resin (A-2).

[0015] The solid capped resin (A-1) useful in the present invention has the unit formula (I-1), (R M 3SiO 1 / 2 ) a (SiO 4 / 2 ) b Z c (wherein each R M is independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, each Z is independently a hydrolyzable group selected from the group consisting of alkoxy, hydroxyl, or a mixture thereof, c is from 0 to a value sufficient such that the hydrolyzable group content of the capped resin is at most 2% by weight based on the weight of the capped resin, a and b have values such that a > 4, b > 0, preferably b > 1, and the value of (a + b) is sufficient such that the number average molecular weight (Mn) of the capped resin is 500 to 8,000 grams per mole (g / mol) as measured by gel permeation chromatography (GPC) analysis). The GPC analysis can be carried out according to the test method described in the following Examples section.)

[0016] R M The hydrocarbon group of R can be selected from the group consisting of an alkyl group, an alkenyl group, an aryl group, an aralkyl group, or a mixture thereof. R M The alkyl group represented by typically has 1 to 20 carbon atoms, 1 to 15 carbon atoms, 1 to 12 carbon atoms, 1 to 10 carbon atoms, 1 to 6 carbon atoms, 1 to 3 carbon atoms, or 1 to 2 carbon atoms. Examples of suitable alkyl groups include methyl, ethyl, propyl, pentyl, hexyl, and cyclohexyl. R M The alkenyl group represented by typically has 2 to 20 carbon atoms, 2 to 10 carbon atoms, 2 to 8 carbon atoms, or 2 to 6 carbon atoms. R M Examples of suitable alkenyl groups represented by include vinyl, allyl, butenyl, and hexenyl. Preferably, the alkyl group is methyl and the alkenyl group is vinyl. R M Examples of the aryl group represented by include cyclopentadienyl, phenyl, anthracenyl, and naphthyl. Each R M can be independently selected from methyl, vinyl, and phenyl. Preferably, at least one-third or at least two-thirds of the R M groups are alkyl groups (e.g., methyl groups). For example, each R M is independently an alkyl group having 1 to 6 carbon atoms, preferably methyl.

[0017] When the value of (a + b) in formula (I-1) is measured by GPC analysis, the Mn of the capped resin is 500 g / mol or more, 1,000 g / mol or more, 1,500 g / mol or more, 2,000 g / mol or more, 2,500 g / mol or more, or 2,700 g / mol or more, and at the same time 8,000 g / mol or less, 7,000 g / mol or less, 6,500 g / mol or less, 6,000 g / mol or less, 5,500 g / mol or less, 5,000 g / mol or less, or 4,700 g / mol or less, which is sufficient. For example, the value of a can be 40 to 55 or 43 to 50. The value of b can be 45 to 65 or 50 to 57.

[0018] The value of c in formula (I-1) ranges from 0 to a value sufficient for the hydrolyzable group content of the capped resin to be from 0 to a maximum of 2%. The hydrolyzable group is typically hydroxyl. For example, the solid capped resin (A-1) contains 2 wt% or less of silicon-bonded hydroxyl (OH) groups (also called "silanol groups"), based on the weight of the capped resin, for example, 1.9 wt% or less, 1.8 wt% or less, 1.7 wt% or less, 1.6 wt% or less, 1.5 wt% or less, 1.4 wt% or less, 1.3 wt% or less, 1.2 wt% or less, 1.1 wt% or less, or 1 wt% or less of silicon-bonded hydroxyl groups. The weight percentage of the silicon-bonded hydroxyl groups can be measured by nuclear magnetic resonance (NMR) spectroscopy. The NMR analysis can be carried out according to the test methods described in the following Examples section.

[0019] The solid uncapped resin (A-2) useful in the present invention has a unit formula (I-2), (R M 3SiO 1 / 2 ) a’ (SiO 4 / 2 ) b’ Z c’ (wherein each R MAnd Z is as described above in the part of the capped resin (A-1), c' has a value sufficient for the hydrolyzable group content of the uncapped resin to be more than 2% by weight and up to 10% by weight based on the weight of the uncapped resin, a' and b' have values such that a' > 4, b' > 0, preferably b' > 1, and the value of (a' + b') is such that when measured by GPC analysis, the Mn of the uncapped resin is 500 to 8,000 g / mol, for example, 1,000 g / mol or more, 1,500 g / mol or more, 2,000 g / mol or more, 2,500 g / mol or more, or 2,700 g / mol or more, and at the same time, 8,000 g / mol or less, 7,000 g / mol or less, 6,500 g / mol or less, 6,000 g / mol or less, 5,500 g / mol or less, 5,000 g / mol or less, or 4,700 g / mol or less). For example, the value of a' can be 40 to 55 or 43 to 50. The value of b' can be 45 to 65 or 50 to 57. The solid uncapped resin may contain silicon-bonded OH groups in an amount of more than 2%, more than 2.5%, or more than 3%. The weight percent of silicon-bonded OH groups can be measured by NMR spectroscopy. GPC analysis and NMR analysis can be carried out according to the test methods described in the following Examples section.

[0020] Solid polyorganosilicate resins useful in the present invention (e.g., the above (A-1) and (A-2)) contain monofunctional units of the formula R M 3SiO 1 / 2 ("M" units) and tetrafunctional silicate units of the formula SiO 4 / 2 ("Q" units). Examples of M units include (Me3SiO 1 / 2 ), (Me2PhSiO 1 / 2 ), or (Me2ViSiO 1 / 2 ), where Me represents methyl, Ph represents phenyl, and Vi represents vinyl. The polyorganosilicate resin contains, as a by-product during resin preparation, units of the formula (R MIt may contain a neopentamer organopolysiloxane having SiO)4Si, such as tetrakis(trimethylsiloxy)silane. The molar ratio of M units to Q units (the "M / Q ratio") in the polyorganosilicate resin, when measured by NMR analysis, is typically in the range of 0.5 to 1.5, 0.65 to 1.3, or 0.8 to 1.2. The M / Q ratio represents the total number of M units to the total number of Q units in the polyorganosilicate resin, and includes the contribution from the neopentamer when present. The polyorganosilicate resin may contain HOSiO 3 / 2 units (TOH units) and / or HOR M 2SiO 1 / 2 and these enter into the calculation of the silicon-bonded hydroxyl content of the polyorganosilicate resin.

[0021] Useful solid polyorganosilicate resins in the present invention (e.g., the above (A-1) and (A-2)) can be prepared by any suitable method such as co-hydrolysis of the corresponding silanes or the silica hydrosol capping method. The solid polyorganosilicate resin can be prepared by the silica hydrosol capping method such as those disclosed in U.S. Patent No. 2,676,182 to Daudt et al., U.S. Patent No. 4,611,042 to Rivers-Farrell et al., and U.S. Patent No. 4,774,310 to Butler et al. The above-mentioned method of 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 to recover a copolymer having monofunctional units and tetrafunctional units. The resulting copolymer generally contains 2 to 5 weight percent of hydroxyl groups. The silicon-bonded hydroxyl groups formed during the preparation of the polyorganosilicate resin can be converted to trihydrocarbon siloxane groups or different hydrolyzable groups by reacting the silicone resin with a silane, disiloxane, or disilazane containing appropriate end groups in a process called capping. The silane containing a hydrolyzable group may be added in a molar excess over the amount required to react with the silicon-bonded hydroxyl groups in the polyorganosilicate resin. The solid polyorganosilicate resin can be prepared as described in, for example, U.S. Patent No. 8,017,712 to Berry et al. and the references cited therein, and U.S. Patent No. 10,351,742 to Brown et al. and the references cited therein, and then the volatile matter can be removed. Solid polyorganosilicate resins (e.g., flake resins) are also commercially available from various suppliers such as Dow Silicones Corporation (Midland, Michigan, USA), Momentive Performance Materials (Albany, New York, USA), and Bluestar Silicones USA Corp. (East Brunswick, New Jersey, USA).

[0022] The starting material (A) may be a mixture of two or more solid polyorganosilicate resins having different structures, Mn, siloxane units, arrangements, and / or silicon-bonded OH contents. For example, the solid-capped resin (A-1) may be present in an amount of 50% by weight or more, 60% by weight or more, 70% by weight or more, 80% by weight or more, 90% by weight or more, 95% by weight or more, or 100% by weight, based on the weight of the starting material (A). The solid non-capped resin (A-2) may be present in an amount of 50% by weight or less, 40% by weight or less, 30% by weight or less, 20% by weight or less, 10% by weight or less, 5% by weight or less, or zero, based on the weight of the starting material (A). The solid polyorganosilicate resin component may consist of the above solid-capped resin (A-1) and solid non-capped resin (A-2), i.e., the total concentration of (A-1) and (A-2) may be equal to 100% by weight based on the weight of the starting material (A).

[0023] The process for preparing the solvent-free PSA composition of the present invention also includes the step of (ii) mixing the above starting material (A) with starting material (B) and optionally starting material (C). The resulting mixture is further cooled to form a silicone-based portion (e.g., step (iii) of the process).

[0024] The starting material (B) useful in the present invention is an aliphatic unsaturated polydiorganosiloxane (B-1), a branched polydiorganosiloxane (B-2), or a mixture of (B-1) and (B-2).

[0025] The aliphatic unsaturated polydiorganosiloxane (B-1) useful in the present invention has the unit formula (II-1), (R 1 2R 2 SiO 1 / 2 ) x (R 1 3SiO 1 / 2 ) y (R 1 R 2 SiO 2 / 2 ) z (R 1 2SiO 2 / 2 ) w (In the formula, each R 1 is independently a monovalent hydrocarbon group having 1 to 20 carbon atoms without aliphatic unsaturation, and each R 2 is independently a monovalent aliphatic unsaturated hydrocarbon group having 2 to 20 carbon atoms, x > 0, y ≥ 0, (x + y) = 2, z ≥ 0, w ≥ 0, (w + z) > 0, and the value of (x + y + z + w) is sufficient for the Mn of the aliphatic unsaturated polydiorganosiloxane to be 5,000 to 50,000 g / mol when measured by GPC analysis). For example, the Mn of the aliphatic unsaturated polydiorganosiloxane (B-1) is 5,200 g / mol or more, 5,500 g / mol or more, 5,800 g / mol or more, 6,000 g / mol or more, 6,200 g / mol or more, 6,500 g / mol or more, or 7,000 g / mol or more, and at the same time, 48,000 g / mol or less, 45,000 g / mol or less, 40,000 g / mol or less, 35,000 g / mol or less, 30,000 g / mol or less, 25,000 g / mol or less, 20,000 g / mol or less, or 18,000 g / mol or less. The GPC analysis can be carried out according to the test method described in the following Examples section. The value of (w + z) is 50 or more, 100 or more, 150 or more, 200 or more, or 300 or more, and at the same time, 600 or less, 500 or less, 450 or less, or 400 or less.

[0026] R 1 typically has 1 to 20 carbon atoms, 1 to 15 carbon atoms, 1 to 12 carbon atoms, 1 to 10 carbon atoms, 1 to 6 carbon atoms, 1 to 3 carbon atoms, or 1 to 2 carbon atoms. Examples of the monovalent hydrocarbon group suitable for R 1 include the above alkyl groups and aromatic groups such as aryl groups and aralkyl groups. Each R 1 may independently be an alkyl group having 1 to 6 carbon atoms. At least 50 mol%, 60 mol% or more, 70 mol% or more, or 80 mol% or more of the monovalent hydrocarbon group represented by R1 may be methyl. The mole percentage of methyl in this specification can be measured by NMR analysis. Preferably, each R 1 is methyl.

[0027] R 2 typically has 2 to 20 carbon atoms, 2 to 10 carbon atoms, 2 to 8 carbon atoms, or 2 to 6 carbon atoms. R 2 The monovalent aliphatic unsaturated hydrocarbon group of R may be an alkenyl group. R 2 Examples of suitable alkenyl groups for R include vinyl, allyl, propenyl (e.g., isopropenyl and / or n-propenyl); butenyl, pentenyl, hexenyl, heptenyl and their branched and straight-chain isomers; and cyclohexenyl. Preferably, the alkenyl group is vinyl. The alkenyl group in the aliphatic unsaturated polydiorganosiloxane may be located at a terminal position, a pendant position, or both a terminal position and a pendant position.

[0028] Examples of suitable aliphatic unsaturated polyorganosiloxanes (B-1) include b1) dimethylvinylsiloxy-terminated polydimethylsiloxane, b2) dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylvinylsiloxane), b3) dimethylvinylsiloxy-terminated polymethylvinylsiloxane, b4) trimethylsiloxy-terminated poly(dimethylsiloxane / methylvinylsiloxane), b5) trimethylsiloxy-terminated polymethylvinylsiloxane, b6) dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylvinylsiloxane), b7) dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylphenylsiloxane), b8) dimethylvinylsiloxy-terminated poly(dimethylsiloxane / diphenylsiloxane), b9) phenyl, methyl, vinylsiloxy-terminated polydimethylsiloxane, b10) dimethylhexenylsiloxy-terminated polydimethylsiloxane, b11) dimethylhexenylsiloxy-terminated poly(dimethylsiloxane / methylhexenylsiloxane), b12) dimethylhexenylsiloxy-terminated polymethylhexenylsiloxane, b13) trimethylsiloxy-terminated poly(dimethylsiloxane / methylhexenylsiloxane), b14) trimethylsiloxy-terminated polymethylhexenylsiloxane, b15) dimethylhexenylsiloxy-terminated poly(dimethylsiloxane / methylhexenylsiloxane), b16) dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylhexenylsiloxane), or combinations thereof. Preferably, the aliphatic unsaturated polyorganosiloxane (B-1) is selected from the group consisting of b1) dimethylvinylsiloxy-terminated polydimethylsiloxane, b2) dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylvinylsiloxane), or a combination of b1) and b2). Aliphatic unsaturated polyorganosiloxanes are well known in the art and may be prepared by methods such as hydrolysis and condensation of the corresponding organohalosilanes or equilibration of cyclic polyorganosiloxanes.

[0029] The branched polyorganosiloxane (B-2) useful in the present invention has the unit formula (II-2), (R 1 3SiO1 / 2 ) g (R 1 2R 2 SiO 1 / 2 ) h (R 1 2SiO 2 / 2 ) i (SiO 4 / 2 ) (In the formula, R 1 and R 2 are as described above, and g, h, and i have values such that 2 ≥ g ≥ 0, 4 ≥ h ≥ 0, 995 ≥ i ≥ 4, and (g + h) = 4, and the value of (g + h + i) is sufficient for the Mn of the branched polyorganosiloxane to be 5,000 to 50,000 g / mol when measured by GPC analysis). The GPC analysis can be carried out according to the test method described in the following Examples section. For example, the Mn of the branched polydiorganosiloxane (B-2) is 5,200 g / mol or more, 5,500 g / mol or more, 5,800 g / mol or more, 6,000 g / mol or more, 6,200 g / mol or more, 6,500 g / mol or more, or 7,000 g / mol or more, and at the same time, 48,000 g / mol or less, 45,000 g / mol or less, 40,000 g / mol or less, 35,000 g / mol or less, 30,000 g / mol or less, 25,000 g / mol or less, 20,000 g / mol or less, or 18,000 g / mol or less. The value of i can be 50 or more, 100 or more, 150 or more, 200 or more, or 250 or more, and at the same time, 600 or less, 500 or less, 400 or less, or 300 or less. The preparation method of the branched polyorganosiloxane (B-2) and examples of suitable branched polyorganosiloxanes (B-2) are disclosed, for example, in U.S. Patent No. 6,806,339 and U.S. Patent Application Publication No. 2007 / 0289495.

[0030] The starting material (B) can be a single aliphatic unsaturated polydiorganosiloxane (B-1), a mixture containing two or more aliphatic unsaturated polydiorganosiloxanes with at least one of the following properties different: structure, Mn, siloxane units, and arrangement, a single branched polydiorganosiloxane (B-2), a mixture of two or more branched polydiorganosiloxanes with at least one of the following properties different: structure, Mn, siloxane units, and arrangement, or a mixture thereof. (B-1) and / or (B-2) may be present in an amount such that when measured with a rotational viscometer, the viscosity of the starting material (B) is 4,000 mPa·s or less, 3,500 mPa·s or less, 3,000 mPa·s or less, 2,500 mPa·s or less, 2,000 mPa·s or less, or 1,500 mPa·s or less at room temperature, and simultaneously 200 mPa·s or more, 300 mPa·s or more, 400 mPa·s or more, or 500 mPa·s or more. The viscosity can be measured according to the test method described in the following Examples section.

[0031] The starting material (B) useful in the present invention may be present in an amount of 46% by weight or more, 47% by weight or more, 48% by weight or more, 49% by weight or more, 50% by weight or more, 51% by weight or more, 52% by weight or more, 53% by weight or more, 54% by weight or more, 55% by weight or more, 60% by weight or more, 62% by weight or more, or 65% by weight or more, and simultaneously 90% by weight or less, 85% by weight or less, 80% by weight or less, 75% by weight or less, 74% by weight or less, 73% by weight or less, or 70% by weight or less, based on the total weight of the starting materials in the solvent-free PSA composition. The total weight of the starting materials in the solvent-free PSA composition can be the combined weight of the starting materials (A) to (E) and, if present, the starting materials (F) and (G) as described later.

[0032] The starting material (C) useful in the present invention is a polydiorganosiloxane gum of unit formula (III), (R 1 2R G SiO 1 / 2 )2(R 1 2SiO 2 / 2 ) d (wherein R 1 is as described above, and each RG is independently a monovalent aliphatic unsaturated hydrocarbon group having 2 to 20 carbon atoms, a hydroxyl group, or a combination thereof, and d has a value sufficient for the Mn of the polydiorganosiloxane gum to be 300,000 g / mol or more, for example, 350,000 g / mol or more, 400,000 g / mol or more, 450,000 g / mol or more, 500,000 g / mol or more, and at the same time, 1,000,000 g / mol or less, 900,000 g / mol or less, 800,000 g / mol or less, 700,000 g / mol or less, or 600,000 g / mol or less when measured by GPC analysis. GPC analysis can be carried out according to the test method described in the following Examples section. For example, the value of d may be 4,000 or more, 4,500 or more, 5,000 or more, 5,500 or more, or 6,000 or more, and at the same time, 10,000 or less, 9,000 or less, 8,000 or less, or 7,000 or less.

[0033] R 1 is as described above in the part of the starting material (B). R G The aliphatic unsaturated hydrocarbon group represented by typically has 2 to 20 carbon atoms, 2 to 10 carbon atoms, 2 to 8 carbon atoms, or 2 to 6 carbon atoms. The aliphatic unsaturated hydrocarbon group may be alkenyl. R G Examples of suitable alkenyl groups represented by include vinyl, allyl, propenyl (for example, isopropenyl, and / or n-propenyl); butenyl, pentenyl, hexenyl, heptenyl and their branched and straight-chain isomers; and cyclohexenyl. Preferably, the alkenyl group is vinyl. The alkenyl group and / or hydroxyl group in the polydiorganosiloxane gum may be located at the terminal position. The starting material (C) can be a mixture of two or more different polydiorganosiloxane gums.

[0034] Examples of suitable polydiorganosiloxane gums include: C1) dimethylvinylsiloxy-terminated polydimethylsiloxane, C2) dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylphenyl)siloxane, C3) dimethylvinylsiloxy-terminated poly(dimethylsiloxane / diphenyl)siloxane, C4) phenyl, methyl, vinyl-siloxy-terminated polydimethylsiloxane, C5) dimethylhexenylsiloxy-terminated polydimethylsiloxane, C6) dimethylhexenyl-siloxy-terminated poly(dimethylsiloxane / methylphenyl)siloxane, C7) dimethylhexenylsiloxy-terminated poly(dimethylsiloxane / diphenyl)siloxane, C8) hydroxyl-terminated polydimethylsiloxane, C9) hydroxyl-terminated poly(dimethylsiloxane / methylphenyl)siloxane, C10) hydroxyl-terminated poly(dimethylsiloxane / diphenyl)siloxane, or mixtures thereof.

[0035] The starting material (C) useful in the present invention may be present in an amount of 0% by weight or more, 0.1% by weight or more, 0.2% by weight or more, 0.5% by weight or more, 0.8% by weight or more, 1% by weight or more, 1.5% by weight or more, or 2% by weight or more, and at the same time, 6% by weight or less, 5.5% by weight or less, 5% by weight or less, 4% by weight or less, 2.3% by weight or less, 2% by weight or less, or 1.6% by weight or less, based on the total weight of all starting materials in the solventless PSA composition.

[0036] The starting materials (A), (B), and (C) are present in amounts such that the weight ratio of (A):[(B)+(C)], i.e., the weight ratio of the amount of starting material (A) to the total amount of starting materials (B) and (C) (referred to as the R / P ratio), is in the range of 0.1 to 1.2, 0.15 to 1.1, 0.2 to 1.0, 0.25 to 0.9, or 0.3 to 0.8.

[0037] The process for preparing the solventless PSA composition of the present invention also includes the step of (iv) mixing the silicone-based portion obtained above with starting materials (D) and (E), and optionally other starting materials including starting materials (F) and / or (G) to form a solventless PSA composition.

[0038] The starting material (D) useful in the present invention is one or more polyorganohydrogensiloxanes. The starting material (D) functions as a crosslinking agent in the hydrosilylation reaction of the solvent-free PSA composition. The polyorganohydrogensiloxane typically has at least 2 or at least 3 silicon-bonded hydrogen atoms per molecule. The polyorganohydrogensiloxane has the unit formula (IV), (R 1 3SiO 1 / 2 )2(R 1 2SiO 2 / 2 ) e (HR 1 2SiO 2 / 2 ) f (wherein R 1 is as described above, e≧0, f≧3, and (e + f) is 4 to 500) may be included.

[0039] R 1 is as described in the part of the starting material (B) above. Preferably, each R 1 is independently an alkyl having 1 to 6 carbon atoms, more preferably methyl. The value of (e + f) may be 4 or more, 5 or more, 7 or more, 10 or more, 20 or more, 30 or more, 40 or more, or 50 or more, and at the same time 500 or less, 400 or less, 200 or less, 150 or less, 140 or less, 130 or less, 120 or less, 110 or less, or 100 or less.

[0040] The polyorganohydrogensiloxane useful in the present invention may contain silicon-bonded hydrogen atoms in an amount of 0.38% by weight or more, 0.5% by weight or more, 0.6% by weight or more, or 0.75% by weight or more, and at the same time 2% by weight or less, 1.9% by weight or less, 1.8% by weight or less, 1.75% by weight or less, 1.7% by weight or less, or 1.6% by weight or less, based on the weight of the polyorganohydrogensiloxane. The content of silicon-bonded hydrogen atoms can be measured by NMR analysis.

[0041] Methods for preparing polyorganohydrogensiloxanes, such as hydrolysis and condensation of organohydridohalosilanes, are well known in the art. Examples of suitable polyorganohydrogensiloxanes include D1) trimethylsiloxy-terminated poly(dimethyl / methylhydrogen)siloxane, D2) trimethylsiloxy-terminated polymethylhydrogensiloxane, D3) dimethylhydrogenoxysilyl-terminated polydimethylsiloxane, D4) dimethylhydrogenoxysilyl-terminated poly(dimethylsiloxane / methylhydrogensiloxane), D5) dimethylhydrogenoxysilyl-terminated polymethylhydrogensiloxane, or combinations thereof.

[0042] Starting material (B) is present in an amount sufficient for the molar ratio of silicon-bonded hydrogen atoms to aliphatic unsaturated hydrocarbon groups (referred to as the SiH / Vi ratio) in all starting materials containing aliphatic unsaturated hydrocarbon groups in the solvent-free PSA composition to be 1 to 10, 1.1 to 8, 1.2 to 7, 1.3 to 6, 1.4 to 5, or 1.5 to 4. Typically, starting material (B) is present in an amount of 0.1 wt% or more, 1 wt% or more, or 2 wt% or more, and at the same time 5 wt% or less, 4 wt% or less, or 3 wt% or less, based on the total weight of the starting materials containing aliphatic unsaturated hydrocarbon groups in the solvent-free PSA composition.

[0043] The starting material (E) useful in the present invention is a hydrosilylation reaction catalyst. The hydrosilylation reaction catalyst can promote the addition reaction between the starting material (B) and the starting material (D). Examples of the hydrosilylation reaction catalyst include platinum group metal catalysts. Such hydrosilylation reaction catalysts include (E1) metals selected from platinum, rhodium, ruthenium, palladium, osmium, and iridium, preferably platinum; (E2) compounds such as chlorotris(triphenylphosphine)rhodium(I) (Wilkinson catalyst), rhodium diphosphine chelates such as [1,2-bis(diphenylphosphino)ethane]dichlorodirhodium or [1,2-bis(diethylphosphino)ethane]dichlorodirhodium, chloroplatinic acid (Speier catalyst), chloroplatinic acid hexahydrate, or metals containing platinum dichloride; (E3) complexes of platinum group compounds and low molecular weight organopolysiloxanes; (E4) platinum group compounds microencapsulated in a matrix or core-shell type structure, or combinations thereof; (E5) complexes microencapsulated in a resin matrix, or combinations thereof. Examples of the complex of platinum and low molecular weight organopolysiloxane include the complex of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane and platinum (Karstedt catalyst). Exemplary hydrosilylation reaction catalysts are described in U.S. Patent No. 3,159,601 and U.S. Patent No. 3,220,972.

[0044] The concentration of the hydrosilylation reaction catalyst is a concentration sufficient to catalyze the hydrosilylation reaction between the silicon-bonded hydrogen atoms and the aliphatic unsaturated groups in the solvent-free PSA composition. Typically, the concentration of the hydrosilylation reaction catalyst is 1 weight ppm (part per million) or more, 5 weight ppm or more, 10 weight ppm or more, 20 weight ppm or more, or 30 weight ppm or more, and at the same time 6,000 weight ppm or less, 5,000 weight ppm or less, 4,000 weight ppm or less, 3,000 weight ppm or less, 2,000 weight ppm or less, 1,000 weight ppm or less, 500 weight ppm or less, 100 weight ppm or less, or 50 weight ppm or less of platinum group metal, based on the total weight of the starting materials in the solvent-free PSA composition, which is sufficient.

[0045] The starting material (F) useful in the present invention is a hydrosilylation reaction inhibitor, which can be optionally used to change the reaction rate between the silicon-bonded hydrogen atoms and the aliphatic unsaturated groups in the solvent-free PSA composition as compared with the reaction rate when the same starting material is used but the inhibitor is omitted. Examples of suitable hydrosilylation reaction inhibitors include acetylenic alcohols such as methylbutynol, ethynylcyclohexanol, dimethylhexynol, 3,5-dimethyl-1-hexyn-3-ol, 1-butyn-3-ol, 1-propyn-3-ol, 2-methyl-3-butyn-2-ol, 3-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol, 3-phenyl-1-butyn-3-ol, 4-ethyl-1-octyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, 1-ethynyl-1-cyclohexanol (ETCH), and combinations thereof; cycloalkenyl siloxanes such as methylvinylcyclosiloxanes exemplified by 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane, and combinations thereof; en-yne compounds such as 3-methyl-3-penten-1-yne, 3,5-dimethyl-3-hexen-1-yne, and combinations thereof; triazoles such as benzotriazole; phosphines; mercaptans; hydrazines; amines such as tetramethylethylenediamine, 3-dimethylamino-1-propene, n-methylpropargylamine, propargylamine, and 1-ethynylcyclohexylamine; dialkyl fumarates such as diethyl fumarate, diallyl fumarate, dialkoxyalkyl fumarates, diallyl maleate, diethyl maleate, and other maleates; nitriles; ethers; carbon monoxide; alkenes such as cyclooctadiene, divinyltetramethyldisiloxane; alcohols such as benzyl alcohol; or mixtures thereof.

[0046] The hydrosilylation reaction inhibitor useful in the present invention may be present in an amount of 0% by weight or more, 0.01% by weight or more, 0.1% by weight or more, 0.2% by weight or more, 0.3% by weight or more, or 1% by weight or more, and at the same time, 5% by weight or less, 4% by weight or less, 3% by weight or less, or 2% by weight or less, based on the total weight of the starting materials in the solvent-free PSA composition.

[0047] The starting material (G) useful in the present invention is a fixing additive. The fixing additive may include an alkoxysilane, a reaction product of vinylacetoxysilane and an epoxy-functional alkoxysilane, a blend and / or reaction product of an alkoxysilane, a polyorganosiloxane having at least one aliphatic unsaturated hydrocarbon group and at least one hydrolyzable group per molecule, and an epoxy-functional alkoxysilane (for example, a blend and / or reaction product of a hydroxy-terminated vinyl-functional polydimethylsiloxane and glycidoxypropyltrimethoxysilane), or a mixture thereof. The alkoxysilane may be an unsaturated or epoxy-functional alkoxysilane, methyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, bis(trimethoxysilyl)propane, and bis(trimethoxysilyl)hexane; tetramethoxysilane, tetraethoxysilane, dimethyldimethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, phenyltrimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, or a mixture thereof. Examples of suitable epoxy-functional alkoxysilanes include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, (epoxycyclohexyl)ethyldimethoxysilane, (epoxycyclohexyl)ethyldiethoxysilane, or a mixture thereof. Examples of suitable unsaturated alkoxysilanes include vinyltrimethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, hexenyltrimethoxysilane, undecylenyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3-acryloyloxypropyltriethoxysilane, or a mixture thereof.Suitable commercially available fixing additives include, for example, SYL-OFF (trademark) 297, SYL-OFF (trademark) 397, and SYL-OFF (trademark) SL9250, all available from Dow Silicones Corporation (Midland, Michigan, USA) (SYL-OFF is a trademark of Dow Silicones Corporation).

[0048] In particular, examples of fixing additives include (G1) vinyltriacetoxysilane, (G2) glycidoxypropyltrimethoxysilane, (G3) a blend or reaction product of (G1) and (G2), and (G4) a blend or reaction product of (G3) and polydimethylsiloxane terminated with a hydroxyl group, a methoxy group, or both a hydroxyl group and a methoxy group.

[0049] The fixing additive useful in the present invention may be present in an amount of 0% by weight or more, 0.01% by weight or more, 0.05% by weight or more, 0.1% or more, or 0.5% by weight or more, and at the same time, 5% by weight or less, 4.5% by weight or less, 4% by weight or less, 3.5% by weight or less, 3% by weight or less, 2.5% by weight or less, 2% by weight or less, 1.5% by weight or less, or 1% by weight or less, based on the total weight of the starting materials in the solventless PSA composition.

[0050] The preparation process of the solvent-free PSA composition of the present invention includes: (i) providing one or more of the above-mentioned other additional starting materials such as starting material (A), starting material (B), and optionally starting material (C); and (ii) simultaneously mixing starting materials (A) and (B), and optionally starting material (C), at a temperature of 100 °C or higher, for example, 110 °C or higher, 120 °C or higher, 130 °C or higher, 140 °C or higher, or 150 °C or higher, and at the same time, 230 °C or lower, 220 °C or lower, 210 °C or lower, 200 °C or lower, 190 °C or lower, or 180 °C or lower. The solid polyorganosilicate resin for starting material (A) (for example, (A-1) and (A-2)) may be in the form of flakes or powder when mixed with starting material (B) and optionally starting material (C). The mixing temperature in step (ii) can typically be selected to form a homogeneous mixture that is visually transparent. As used herein, "homogeneous mixture" refers to a mixture in which no phase separation or layering is observed when observed with the naked eye. The mixing of the starting materials can be achieved by any of the techniques well known in the art, such as grinding, blending, extrusion, and stirring, either in a batch process or a continuous process. The mixing time of the above-mentioned starting materials may vary depending on the molecular weights and concentrations of starting materials (A) and (B), and / or the mixing method, and is, for example, 10 minutes to 4 hours, 0.5 hours to 2 hours, or 1 hour to 2 hours.

[0051] The preparation process of the solvent-free PSA composition of the present invention further includes: (iii) cooling the mixture obtained in step (ii) to form a silicone-based part. The cooling temperature may be 60 °C or lower, 50 °C or lower, 40 °C or lower, 30 °C or lower, or even 25 °C or lower. The silicone-based part is liquid at room temperature and is typically a homogeneous mixture. The viscosity of the silicone-based part, when measured with a rotational viscometer, is less than 5,000 mPa·s at room temperature, for example, 4,950 mPa·s or lower, 4,900 mPa·s or lower, 4,800 mPa·s or lower, 4,500 mPa·s or lower, 4,000 mPa·s or lower, 3,500 mPa·s or lower, 3,000 mPa·s or lower, 2,500 mPa·s or lower, or 2,000 mPa·s or lower. The viscosity can be measured according to the test method described in the following Examples section.

[0052] The preparation process of the PSA composition of the present invention further includes the step of (iv) mixing the silicone-based part obtained in step (iii) with the starting materials (D) hydrosilylation reaction catalyst and (E) polyorganohydrogensiloxane, and optionally other additional starting materials including a hydrosilylation reaction inhibitor and / or a fixing additive. When a hydrosilylation reaction inhibitor is present, for example, when preparing a solventless PSA composition as a one-component composition, the hydrosilylation reaction inhibitor may be added to the silicone-based part before the hydrosilylation reaction catalyst. The preparation process of the solventless PSA composition can be used for the preparation of a multi-component composition including at least the silicone-based part and the curing agent part obtained in step (iii) of the above process. The curing agent part can be prepared by combining at least the starting materials containing a hydrosilylation reaction catalyst, polyorganohydrogensiloxane, and optionally the other additional starting materials described above. The hydrosilylation reaction inhibitor may be included in one or more of the silicone-based part, the curing agent part, or a separate additional part. The fixing additive may be added to the silicone-based part and / or the curing agent part, or added as a separate additional part. These parts are combined immediately before using the solventless PSA composition. When using a two-component composition, the weight ratio of the amount of the base part to the amount of the curing agent part can be in the range of 1:1 to 10:1.

[0053] The preparation process of the solvent-free PSA composition of the present invention can be carried out in a state where there is substantially no solvent, that is, without intentionally adding a solvent during the preparation of the solvent-free PSA composition. For example, the process of the present invention does not require adding a solvent to dissolve one or more of the starting materials such as the solid polyorganosilicate resin component in the solvent-free PSA composition, and / or adding a solvent to the silicone-based portion. "Substantially no solvent" means that based on the total weight of the starting materials in the solvent-free PSA composition, the solvent is 100 weight ppm or less, 80 weight ppm or less, 50 weight ppm or less, or even zero. The solvent content can be measured by gas chromatography (GC). As used herein, "solvent" refers to any compound that can dissolve the solid polyorganosilicate resin component (starting material (A)), that is, the polyorganosilicate resin component is soluble in the solvent. The solvent can be an organic solvent such as a saturated or unsaturated aliphatic or aromatic hydrocarbon, for example, a hydrocarbon compound having 8 to 18 carbon atoms per molecule and at least one aliphatic unsaturation such as benzene, toluene, xylene, hexane, heptane, octane, isoparaffin, tetradecene; a ketone such as acetone, methyl ethyl ketone, or methyl isobutyl ketone; an acetate such as ethyl acetate or isobutyl acetate; a glycol ether such as propylene glycol methyl ether, dipropylene glycol methyl ether, propylene glycol n-butyl ether, an ether such as diisopropyl ether, 1,4-dioxane; a cyclic siloxane having an average degree of polymerization of 3 to 10 such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, and / or decamethylcyclopentasiloxane; or a mixture thereof.

[0054] Since there is substantially no solvent, the process for preparing the solvent-free PSA composition does not involve (i.e., does not include) an extra stripping procedure for removing the solvent, such as stripping the solvent. By the process of the present invention, it is realized to prepare a solvent-free PSA composition without using a solvent, and at the same time, it is realized to provide a desired low viscosity as described below for the obtained solvent-free PSA composition. The PSA composition prepared by the process of the present invention is solvent-free. The solvent-free PSA composition either does not contain a solvent or may contain a trace amount of residual solvent due to the supply of starting materials in the PSA composition, for example, less than 100 weight ppm of solvent based on the total weight of the solvent-free PSA composition (e.g., based on the total weight of the starting materials in the solvent-free PSA composition). The content of the residual solvent in the solvent-free PSA composition can be measured by gas chromatography (GC). The solvent-free PSA composition prepared by the process of the present invention can provide a low viscosity that makes it applicable to directly coat the solvent-free PSA composition onto a substrate without the need to add a solvent to the solvent-free PSA composition before use. For example, the solvent-free PSA composition typically has a viscosity of less than 5,000 mPa·s at room temperature, such as 4,950 mPa·s or less, 4,900 mPa·s or less, 4,800 mPa·s or less, 4,500 mPa·s or less, 4,000 mPa·s or less, 3,500 mPa·s or less, 3,000 mPa·s or less, 2,500 mPa·s or less, or 2,000 mPa·s or less when measured by a rotational viscometer within 0.5 hours after mixing all the starting materials of the PSA composition together. The viscosity can be measured according to the test method described in the following Examples section.

[0055] The present invention also relates to a pressure-sensitive adhesive containing a cured product of a solvent-free PSA composition, that is, a pressure-sensitive adhesive formed by curing a solvent-free PSA composition by a hydrosilylation reaction. By applying the solvent-free PSA composition onto a substrate, adhesive articles such as films and tapes can be manufactured. The present invention also relates to a method for manufacturing an adhesive article such as a protective film, the manufacturing method including applying a solvent-free PSA composition onto a substrate and curing the solvent-free PSA composition. Applying the solvent-free PSA composition onto a substrate can be performed by various means including, for example, dispensing, spinning, thin-film coating, spraying, jetting, dipping, pouring, screen printing, or by using a brush, roller or coating bar such as a gravure coater, comma coater, offset coater, offset-gravure coater, roller coater, reverse roller coater, air knife coater, or curtain coater. The substrate can be any material that can withstand the following curing conditions used to cure the solvent-free PSA composition to form PSA on the substrate. Suitable substrates include, for example, 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); glass cloth, aluminum foil, titanium, copper foil, nickel, silver, or gold. The substrate may be a PET or PI film.

[0056] The method for manufacturing an article can optionally further include treating the substrate before applying the solvent-free PSA composition. The treatment of the substrate can be carried out by any suitable means such as applying a primer or subjecting the substrate to corona discharge treatment, etching, or plasma treatment before applying the solvent-free PSA composition to the substrate.

[0057] Since no solvent is present in the preparation process of the solvent-free PSA composition of the present invention, the method for manufacturing an adhered article does not include (i.e., does not have) steps of removing a solvent, for example, before and / or during the curing of the solvent-free PSA composition. The curing of the solvent-free PSA composition can be carried out at a high temperature of up to 200 °C, for example, 80 to 200 °C, 100 to 160 °C, or 110 to 150 °C, for a time sufficient to cure the solvent-free PSA composition, for example, 30 seconds to 1 hour, or 1 to 5 minutes. Thereby, a pressure-sensitive adhesive is formed on the substrate. The amount of the solvent-free PSA composition applied to the substrate varies depending on the specific application, and can be, for example, an amount sufficient for the film thickness of the pressure-sensitive adhesive after curing to be 5 microns (μm) to 100 μm, 6 μm to 50 μm, 8 μm to 40 μm, or 10 μm to 30 μm.

[0058] The method for manufacturing an adhered article of the present invention can optionally further include applying a removable release liner to the PSA on the opposite side of the substrate such that the PSA is present between the substrate and the release liner. The release liner can be applied before, during, or after the curing of the solvent-free PSA composition.

[0059] The adhesive article manufactured as described above is useful for electronic applications such as display devices. The solvent-free PSA composition of the present invention can be cured to form a PSA having a peel adhesion of 20 g / in (7.87 grams / cm) or less, for example, 0.5 g / in to 20 g / in, 1 g / in to 15 g / in, 3 g / in to 10 g / in, on glass or stainless steel. Since the PSA prepared from the solvent-free PSA composition has low adhesiveness to glass and stainless steel, the protective film is suitable for use in surface protection of electronic devices, for example, screen or other surface protection at the time of shipment of devices such as smartphones and tablets, or screen protection of such devices by end users. The adhesive article may be a protective film useful for protecting display glass.

Examples

[0060] Next, some embodiments of the present invention will be described in the following examples. Unless otherwise specified, all parts and percentages are by weight.

[0061] Except for ETCH (available from BASF) and tetradecene (available from BP), all of the following materials shown in Table 1 are available from Dow Silicones Corporation.

[0062]

Table 1

[0063] In the examples and when determining the properties and characteristics described herein, the following standard analytical instruments and methods are used.

[0064] NMR analysis described in column 32 of reference example 2 of U.S. Patent No. 9,593,209 29 Using Si NMR technology, the weight percentage of silicon-bonded hydroxyl groups, the molar percentage of methyl, the amount of M~Q units, the content of silicon-bonded hydrogen atoms, and the vinyl content were measured.

[0065] Gel permeation chromatography (GPC) analysis The number average molecular weight (Mn) of the starting material (A) was measured as follows using GPC analysis. The sample was diluted with high-performance liquid chromatography (HPLC) grade ethyl acetate (about 10 milligrams / milliliter (mg / mL)), filtered through a 0.45 μm polytetrafluoroethylene (PTFE) filter, and analyzed by GPC. The injection volume of the sample was 100 microliters (μL). The columns used in this analysis included one PLgel Mixed D, one PLgel Mixed E, and a guard column. The columns and all detectors were heated to 35°C. ASTM-certified polystyrene with a weight average molecular weight (Mw) of 113,500 was used for instrument calibration (100 μL injection). For data collection, a Viscotek TDA-305 triple detector array was used together with a Viscotek GPCmax autosampler. Omni Sec version 4.6 was utilized for data acquisition.

[0066] The Mn of starting materials (B) and (C) was measured as follows using GPC analysis. The chromatography apparatus consisted of a Waters 2695 separation module equipped with a vacuum degassing device and a Waters 2414 refractive index detector. Separation was carried out using three Styragel (trademark) HR columns (300 millimeters (mm) × 7.8 mm) (molecular weight separation range 100 to 4,000,000), followed by a Styragel (trademark) guard column (30 mm × 4.6 mm). Styragel is a trademark of Waters Technologies Corporation. Analysis was performed using certified grade tetrahydrofuran (THF) flowing at 1.0 milliliter per minute (mL / min) as the eluent, and both the column and the detector were heated to 35°C. 0.050 grams was weighed and placed in a glass vial (8 mL) and diluted with 5 mL of THF to prepare a 1.0 wt / v% sample. The sample solution was filtered through a 0.45 μm PTFE filter and then transferred to a glass autosampler vial. The injection volume used was 100 μL, and data was collected for 37 minutes (min). Data collection was performed using Waters Empower GPC software. Data analysis was performed using Agilent Cirrus software. The molecular weight was measured by comparison with a calibration curve (third order) created using polystyrene standards covering a molecular weight range of 474 to 1,270,000.

[0067] Adhesion test At least 50 grams of a silicone PSA composition sample was applied onto a polyethylene terephthalate (PET) film using four bird bars and then cured in an oven at 140°C for 2 minutes. After curing, the coating thickness of the obtained PSA was measured with a micrometer (micrometer) and shown in Table 2. The film with the obtained silicone PSA was cooled and cut into 1-inch wide tapes.

[0068] These tape samples were laminated onto clean substrates by reciprocating a 2-kilogram (kg) roller twice so that the silicone PSA contacted the substrates, and then held at 25 °C for 24 hours before testing. The substrates were stainless steel (SS) or glass. Next, the adhesion of each tape to the substrate was tested by peeling each tape from the substrate at an angle of 180 degrees (180°) at a speed of 12 inches per minute (0.3 meters per minute) using a TMI peel adhesion tester. The unit of adhesion on the substrate is reported in g / in. The results are shown in Table 2.

[0069] Viscosity The viscosity was measured at room temperature of 23 ± 2 °C at a speed of 10 revolutions per minute (rpm) using a rotational viscometer (Brookfield RVDV-I+PRO viscometer) equipped with spindle #6.

[0070] Gas chromatography (GC) Residual solvents were measured using GC. A sample (0.05 grams) was added to a 2 mL vial, and then treated with 1 mL of hexane to form a hexane solution (10 μL of dodecane was used as an internal standard). The hexane solution was analyzed using GC with flame ionization detection. The experimental relative response factor (RRF for xylene = 0.934) was used in the calculation. The conditions and parameters of the GC instrument used were as follows.

[0071] GC instrument: Agilent 6890N; oven: from 40 °C (3 minutes) to 310 °C (35 minutes) at 15 °C / min. Injector: 280 °C, 18.5 psi, split 20:1; column: DB-5 MS UI, 30 meters (m) × 0.25 mm × 0.25 μm; detector: FID, temperature: 300 °C, H2 flow rate: 40.0 mL / min, air flow rate: 450.0 mL / min, make-up flow rate: 45 mL / min; injection volume: 1.0 μL.

[0072] Examples 1 - 8 Based on the formulation shown in Table 2, the solid resin and vinyl polymer (and / or gum if present) were added to a flask equipped with a stirrer and mixed with stirring. The contents of the flask were heated and held at 150 °C for 2 hours with stirring, and a transparent and homogeneous mixture was obtained. Next, the mixture in the flask was cooled to room temperature to form a homogeneous liquid silicone-based part. The viscosity of the silicone-based part was measured according to the above test method, and the results are shown in Table 2.

[0073] Next, an ETCH inhibitor was added to the base part and mixed for 5 minutes. A crosslinking agent, a catalyst, and a fixing additive were further sequentially added, and after each starting material was mixed for at least 1 minute, another starting material was added. The adhesion properties of the obtained silicone PSA composition were evaluated according to the above adhesion test method.

[0074] As shown in Table 2, the base parts of the solvent-free PSA compositions of Examples 1 to 8 all showed viscosities of less than 5000 mPa·s. The base part of Example 1 had a residual solvent of less than 0.2 ppm when measured by the above GC. The solvent-free PSA compositions of Examples 1 to 8 were directly coated on a PET film and cured to form a PSA having an adhesive force of 20 g / in or less on stainless steel or glass, which is suitable for protective film applications.

[0075]

Table 2

[0076] Comparative Examples A and B Based on the formulations shown in Table 3, the base portions of Comparative Example A and Comparative Example B were each prepared according to the procedure described in Example 1. Next, the inhibitors, crosslinking agents, catalysts, and fixing additives shown in Table 3 were sequentially added to the obtained base portions. The mixtures of Comparative Example A and Comparative Example B obtained both gelled.

[0077]

Table 3

[10] The process according to any one of [1] to [9] above, wherein the hydrosilylation reaction catalyst contains platinum.

[11] The process according to any one of [1] to

[10] above, wherein the starting material (C) is present in an amount of 0 to 6% by weight based on the total weight of the starting materials in the solventless pressure-sensitive adhesive composition.

[12] The process according to any one of [1] to

[11] above, wherein the polyorganohydrogensiloxane contains the unit formula (IV): (R

[13] The process according to any one of [1] to

[12] above, wherein the process is carried out in a state where substantially no solvent is present. 1 3

[14] A solventless pressure-sensitive adhesive composition prepared by the process according to any one of [1] to

[13] above. 1 / 2 ) 2 (R 1 2

[15] A method for producing an adhered article, comprising: 2 / 2 ) e

[16] Optionally, (1) a step of treating the surface of a substrate; 1 2

[17] (2) a step of coating the surface of the substrate with the solventless pressure-sensitive adhesive composition according to

[14] above. 2 / 2 ) f ​ 1 ​ ​ ​ ​ ​ ​ (3) A step of curing the solvent-free pressure-sensitive adhesive composition, and a manufacturing method comprising the same.

Claims

1. A process for preparing a pressure-sensitive adhesive composition, comprising: (i) providing a starting material (A), a solid polyorganosilicate resin component, wherein the solid polyorganosilicate resin component comprises: (A-1) based on the weight of the starting material (A), more than 30% by weight to 100% by weight of a solid capped resin of unit formula (I-1), wherein R is an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a combination thereof; R' is an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a combination thereof; R'' is an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a combination thereof; X is a hydrolyzable group selected from the group consisting of alkoxy, hydroxyl, or a mixture thereof; c is from 0 to a value sufficient for the hydrolyzable group content of the capped resin to be at most 2% by weight based on the weight of the capped resin; a and b have values such that a>4, b>0, and the value of (a + b) is sufficient for the number average molecular weight of the capped resin to be 500 to 8,000 g / mol), (R Ｍ ３ SiO １／２ ) ａ (SiO ４／２ ) ｂ Z ｃ (In the formula, each R Ｍ is independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, and each Z is independent wherein X is a hydrolyzable group selected from the group consisting of alkoxy, hydroxyl, or a mixture thereof; and c is from 0 to a value sufficient for the hydrolyzable group content of the capped resin to be at most 2% by weight based on the weight of the capped resin; a and b have values such that a>4, b>0, and the value of (a + b) is sufficient for the number average molecular weight of the capped resin to be 500 to 8,000 g / mol; and (a + b) has a value such that a>4, b>0, and the value of (a + b) is sufficient for the number average molecular weight of the capped resin to be 500 to 8,000 g / mol), and (a + b) has a value such that a>4, b>0, and the value of (a + b) is sufficient for the number average molecular weight of the capped resin to be 500 to 8,000 g / mol), and (A-2) based on the weight of the starting material (A), 0 to less than 70% by weight of a solid uncapped resin of unit formula (I-2), wherein R is an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a combination thereof; R' is an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a combination thereof; R'' is an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a combination thereof; X is a hydrolyzable group selected from the group consisting of alkoxy, hydroxyl, or a mixture thereof; c' is a value sufficient for the hydrolyzable group content of the uncapped resin to be more than 2% by weight to 10% by weight based on the weight of the uncapped resin; a' and b' have values such that a'>4, b'>0, and the value of (a' + b') is sufficient for the number average molecular weight of the uncapped resin to be 500 to 8,000 g / mol), (R Ｍ ３ SiO １／２ ) ａ’ (SiO ４／２ ) ｂ’ Z ｃ’ (wherein R Ｍ and Z are as defined above, and a' and b' satisfy a' > 4 and b' > 0 wherein R is an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a combination thereof; R' is an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a combination thereof; R'' is an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a combination thereof; X is a hydrolyzable group selected from the group consisting of alkoxy, hydroxyl, or a mixture thereof; c' is a value sufficient for the hydrolyzable group content of the uncapped resin to be more than 2% by weight to 10% by weight based on the weight of the uncapped resin; and (a' + b') has a value such that a'>4, b'>0, and the value of (a' + b') is sufficient for the number average molecular weight of the uncapped resin to be 500 to 8,000 g / mol; and c' has a value sufficient for the hydrolyzable group content of the uncapped resin to be more than 2% by weight to 10% by weight based on the weight of the uncapped resin), and a step comprising: and (ii) mixing the starting material (A) with the starting material (B) and optionally the starting material (C) at a temperature of 100°C or higher, wherein the starting material (B) is an aliphatic unsaturated polyorganosiloxane (B-1), a branched polyorganosiloxane (B-2), or a mixture of (B-1) and (B-2), wherein the aliphatic unsaturated polyorganosiloxane (B-1) has a unit formula (II-1), wherein R is an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a combination thereof; R' is an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a combination thereof; R'' is an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a combination thereof; X is a hydrolyzable group selected from the group consisting of alkoxy, hydroxyl, or a mixture thereof; x, y, z, and w have values such that x>0, y≧0, (x + y)=2, z≧0, w≧0, (w + z)>0, and the value of (x + y + z + w) is sufficient for the number average molecular weight of the aliphatic unsaturated polyorganosiloxane to be 5,000 to 50,000 g / mol), wherein R is an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a combination thereof; R' is an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a combination thereof; R'' is an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a combination thereof; X is a hydrolyzable group selected from the group consisting of alkoxy, hydroxyl, or a mixture thereof; (R １ ２ R ２ SiO １／２ ) ｘ (R １ ３ SiO １／２ ) ｙ (R １ R ２ SiO ２／２ ) ｚ (R １ ２ SiO ２／２ ) ｗ (In the formula, each R １ is independently a monovalent hydrocarbon having 1 to 20 carbon atoms and not containing an aliphatic unsaturation is a hydrogen group, and each R ２ is independently a monovalent aliphatic unsaturated hydrocarbon having 2 to 20 carbon atoms x, y, z, and w have values such that x>0, y≧0, (x + y)=2, z≧0, w≧0, (w + z)>0, and the value of (x + y + z + w) is sufficient for the number average molecular weight of the aliphatic unsaturated polyorganosiloxane to be 5,000 to 50,000 g / mol; and (x + y + z + w) has a value such that x>0, y≧0, (x + y)=2, z≧0, w≧0, (w + z)>0, and the value of (x + y + z + w) is sufficient for the number average molecular weight of the aliphatic unsaturated polyorganosiloxane to be 5,000 to 50,000 g / mol), wherein R is an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a combination thereof; R' is an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a combination thereof; R'' is an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a combination thereof; X is a hydrolyzable group selected from the group consisting of alkoxy, hydroxyl, or a mixture thereof; and (x + y + z + w) has a value such that x>0, y≧0, (x + y)=2, z≧0, w≧0, (w + z)>0, and the value of (x + y + z + w) is sufficient for the number average molecular weight of the aliphatic unsaturated polyorganosiloxane to be 5,000 to 50,000 g / mol), wherein the branched polyorganosiloxane (B-2) has a unit formula (II-2), (R １ ３ SiO １／２ ) ｇ (R １ ２ R ２ SiO １／２ ) ｈ (R １ ２ SiO ２／２ ) ｉ ( SiO ４／２ ) (wherein, R １ and R ２ are as defined above, and g, h and i are such that 2 ≧ g ≧ 0, 4 ≧ h ≧ wherein R is an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a combination thereof; R' is an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a combination thereof; R'' is an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a combination thereof; X is a hydrolyzable group selected from the group consisting of alkoxy, hydroxyl, or a mixture thereof; g, h, and i have values such that 0.995≧i≧4, (g + h)=4, and the value of (g + h + i) is sufficient for the number average molecular weight of the branched polyorganosiloxane to be 5,000 to 50,000 g / mol), wherein R is an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a combination thereof; R' is an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a combination thereof; R'' is an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a combination thereof; X is a hydrolyzable group selected from the group consisting of alkoxy, hydroxyl, or a mixture thereof; g, h, and i have values such that 0.995≧i≧4, (g + h)=4, and the value of (g + h + i) is sufficient for the number average molecular weight of the branched polyorganosiloxane to be 5,000 to 50,000 g / mol; and (g + h + i) has a value such that 0.995≧i≧4, (g + h)=4, and the value of (g + h + i) is sufficient for the number average molecular weight of the branched polyorganosiloxane to be 5,000 to 50,000 g / mol), wherein the starting material (C) is a polydiorganosiloxane gum of unit formula (III), (R １ ２ R Ｇ SiO １／２ ) ２ (R １ ２ SiO ２／２ ) ｄ (In the formula, R １ is as described above, and each R Ｇ independently has 2 to 20 carbon atoms A monovalent aliphatic unsaturated hydrocarbon group, a hydroxyl group, or a combination thereof, and d has a value sufficient for the number average molecular weight of the said polydiorganosiloxane gum to be 300,000 g / mol or more), wherein the number average molecular weight of the polydiorganosiloxane gum is 300,000 g / mol or more and has a value sufficient for this). The starting materials (A), (B), and (C) are present in amounts such that the weight ratio of the amount of starting material (A) to the total amount of starting materials (B) and (C) (if present) is 0.1 to 1.

2. Step, and, (iii) cooling the mixture obtained in step (ii) to form a silicone-based portion having a viscosity of less than 5,000 mPa·s at room temperature; Step, (iv) mixing the silicone-based portion obtained in step (iii) with starting material (D) a polyorganohydrogensiloxane, starting material (E) a hydrosilylation reaction catalyst, optionally starting material (F) a hydrosilylation reaction inhibitor, and optionally starting material (G) a fixing additive, thereby forming the solventless pressure-sensitive adhesive composition. The process includes the step of forming the solventless pressure-sensitive adhesive composition by mixing them, and the process is carried out in a state where substantially no solvent is present.

2. The process according to claim 1, wherein the alkenyl group has a carbon atom as defined in claim 2. Each R １ is independently an alkyl group having 1 to 6 carbon atoms, and each R ２ is independently 2 to 6

3. The process according to claim 1, wherein the aliphatic unsaturated polydiorganosiloxane (B-1) and the branched polydiorganosiloxane (B-2) each independently have a number average molecular weight of 5,500 to 20,000 g / mol.

4. The process according to claim 1, wherein the mixing in step (ii) is carried out at a temperature of 120 to 230°C.

5. The process according to claim 1, wherein starting material (B) has a viscosity of 3,000 mPa·s or less at room temperature.

6.

7.

8. The starting materials are present in amounts such that the molar ratio of silicon-bonded hydrogen atoms to aliphatic unsaturated groups in the solventless pressure-sensitive adhesive composition is 1 to 10.

9. The process according to claim 1, wherein the weight ratio of the amount of starting material (A) to the total amount of starting materials (B) and (C) (if present) is in the range of 0.3 to 0.

8. Each R Ｍ which is independently an alkyl group having 1 to 6 carbon atoms, the pro according to claim 1

10.

11. The process according to claim 1, wherein the solventless pressure-sensitive adhesive composition has a viscosity of less than 5,000 mPa·s at room temperature.

12. The process according to claim 1, wherein the hydrosilylation reaction catalyst contains platinum.

13. Starting material (C) is 0 based on the total weight of the starting materials in the solventless pressure-sensitive adhesive composition.

14.

15.

16.

17.

18.

19.

20. The process according to claim 1, present in an amount of from 0 to 6% by weight.

12. wherein the polyorganohydrogensiloxane has the unit formula (IV): (R １ ３ SiO １／２ ) ２ (R １ ２ SiO ２／２ ) ｅ (HR １ ２ SiO ２／２ ) ｆ (In the formula, R １ is as described above where e ≧ 0, f ≧ 3, and (e + f) is from 4 to 500), comprising the process according to claim 1 as described.

13. The process according to claim 1, wherein the process is carried out using a solvent of 80 ppm by weight or less based on the total weight of the starting materials in the solventless pressure-sensitive adhesive composition.

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