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CN-117751174-B - Curable composition for silicone pressure sensitive adhesives

CN117751174BCN 117751174 BCN117751174 BCN 117751174BCN-117751174-B

Abstract

A curable composition comprising (A) a polydiorganosiloxane component comprising (A1) from greater than 3.1 to 20% by weight of an aliphatically unsaturated polydiorganosiloxane polymer and (A3) a hydroxy-terminated polydiorganosiloxane gum of the formula (A-III), (B) a polyorganosiloxane resin component comprising (B1) a blocked resin, (B2) from greater than 18.53 to 54.3% by weight of an unblocked resin, wherein the weight ratio of the unblocked resin (B2) to the blocked resin (B1) is from greater than 0.51 to 58.82, wherein component (A) and component (B) are present in an amount to provide a weight ratio of (B) from 1.2:1 to less than 1.62:1, (C) a polyorganosiloxane resin component providing the curable composition with 5 to 50 mole percent of silicon-bonded hydrogen alkenyl groups, (B2) from greater than 18.53 to 54.3% by weight of an unblocked resin, wherein the weight ratio of component (B2) to the blocked resin (B1) is from greater than 0.51 to 58.82, wherein the weight percent of the composition is present in an addition catalyst in an amount sufficient to provide an addition reaction of (E) to a molar ratio of (C) of hydrogen groups of from 1.017 to a total weight percent, and wherein the addition catalyst is present in an addition amount of (D) to a total weight percent of (D) of the silicon-containing platinum group is from 0.082, and the addition to a weight percent of an addition catalyst is from 0.082, wherein the addition to the weight of the catalyst is from 0.1000% by weight of the silicon-containing (A) to the silicon-containing an addition catalyst.

Inventors

  • CAO QING
  • ZHANG SHENGLAN
  • MA CHAO

Assignees

  • 美国陶氏有机硅公司

Dates

Publication Date
20260508
Application Date
20220330

Claims (10)

  1. 1. A curable composition, the curable composition comprising: (A) Polydiorganos a silicone component which is selected from the group consisting of, the polydiorganic the silicone component comprises: (A1) From greater than 3.1% to 20% by weight of an aliphatic unsaturated polydiorganosiloxane polymer of formula (a-I): R M (3-c) R U c SiO-(R U R M SiO) a -(R M 2 SiO) b -SiR U d R M (3-d) (A-I) Wherein each R M is independently selected from the group consisting of monovalent hydrocarbon groups of 1 to 30 carbon atoms free of aliphatic unsaturation and monovalent halogenated hydrocarbon groups free of aliphatic unsaturation, each R U is independently an alkenyl group, and the average of the subscripts a, b, c, and d is such that a≥0, b > 0, c is zero or 1, d is zero or 1, the number (a+b) is 100 to 2000, and the number (a+c+d) is≥2, and (A3) Hydroxyl-terminated polydiorganosiloxane gums of unit formula (a-III): {(HO)R M 2 SiO 1/2 } 2 (R M 2 SiO 2/2 ) e (A-III) wherein each R M is independently selected from the group consisting of monovalent hydrocarbon groups of 1 to 30 carbon atoms free of aliphatic unsaturation and monovalent halogenated hydrocarbon groups free of aliphatic unsaturation, and subscript e has a value sufficient to impart (A3) a plasticity of 20 mils (0.51 mm) to 80 mils (2.03 mm) to the hydroxy-terminated polydiorganosiloxane gum, wherein plasticity is measured by applying A1 kilogram (kg) load at 25 ℃ to a spherical sample weighing 4.2 grams (g) for 3 minutes based on ASTM D926 and the result is measured in thousandths of an inch (mil), and the procedure is based on ASTM D926, which is present in an amount that provides a weight ratio of the hydroxy-terminated polydiorganosiloxane gum (A3) to the aliphatic unsaturated polydiorganosiloxane polymer (A1) of 0.89:1; (B) A polymeric organosilicate resin component, the polyorganosilicate resin component comprises: (B1) A blocked resin of unit formula (B-I) (R M 3 SiO 1/2 ) z (SiO 4/2 ) o Z f wherein each R M is independently selected from the group consisting of a monovalent hydrocarbon group of 1 to 30 carbon atoms free of aliphatic unsaturation and a monovalent halogenated hydrocarbon group free of aliphatic unsaturation, each Z is independently a hydrolyzable group, subscript f is zero to a value sufficient to impart up to 2% hydrolyzable group content to the blocked resin, and subscripts Z and o have values such that o >1, Z > 4, and the amount (o+z) has a value sufficient to provide the blocked resin with a number average molecular weight of 500g/mol to < 7,000 g/mol; (B2) An unblocked resin of unit formula (B-II) from greater than 18.53 to 54.3 weight percent (R M 3 SiO 1/2 ) z' (SiO 4/2 ) o' Z f' ), wherein each R M is independently selected from the group consisting of monovalent hydrocarbon groups of 1 to 30 carbon atoms free of aliphatic unsaturation and monovalent halogenated hydrocarbon groups free of aliphatic unsaturation, each Z is independently a hydrolyzable group, subscript f ' has a value sufficient to impart a hydrolyzable group content of greater than 3 to 10% to the unblocked resin, and subscripts Z ' and o ' have values such that o ' >1, Z ' > 4, and the number (o ' +z ') has a value sufficient to provide the unblocked resin with a number average molecular weight of from 500g/mol to < 7,000 g/mol; Wherein the weight ratio of the unblocked resin (B2) to the blocked resin (B1) is greater than 0.51 to 58.82; Wherein (a) the polydiorganosiloxane component and (B) the polyorganosiloxane resin component are present in an amount to provide a weight ratio of the polyorganosiloxane resin component (B) to the polydiorganosiloxane component (a) of from 1.2:1 to less than 1.62:1; (C) Polyorganosiloxane of the unit formula (C-I): (R M 3 SiO 1/2 ) p (R M 2 SiO 2/2 ) q (R M SiO 3/2 ) r (SiO 4/2 ) s (R M HSiO 2/2 ) t (R M 2 HSiO 1/2 ) u (C-I), Wherein each R M is independently selected from the group consisting of monovalent hydrocarbon groups of 1 to 30 carbon atoms free of aliphatic unsaturation and monovalent halogenated hydrocarbon groups free of aliphatic unsaturation, and the values of subscripts p, q, R, s, t and u are such that p≥gtoreq.0, r≥0, s≥0, t≥0, u≥0, (t+u) gtoreq.2, and the amount (p+q+r+s+t+u) is sufficient to provide the polyorganosiloxane with a degree of polymerization of 5 to 100, present in an amount that provides the curable composition with a molar ratio of silicon-bonded hydrogen atoms to alkenyl groups of 5 to 50; (D) A hydrosilylation catalyst in an amount sufficient to provide 1ppm to 1000ppm of a platinum group metal, and (E) A condensation reaction catalyst; wherein the alkenyl group content in the curable composition is in the range of 0.017 wt% to 0.089 wt%; Wherein the weight percentages are relative to the combined weight of components (A), (B), (C), (D) and (E).
  2. 2. The curable composition of claim 1 further comprising (F) 0.001 to 5 wt.% of a hydrosilylation reaction inhibitor and (G) 0.01 to 5 wt.% of a fixing additive or mixtures thereof, wherein the weight percentages are based on the combined weight of components (a), (B), (C), (D) and (E).
  3. 3. The curable composition of claim 1 wherein in formula (A-I), each R M is independently selected from the group consisting of alkyl groups of 1 to 6 carbon atoms, each R U is independently selected from the group consisting of vinyl, allyl, and hexenyl, and the amount (a+b) is sufficient to impart 300 milliPa to the aliphatically unsaturated polydiorganosiloxane polymer Second to 100,000 mPa Values of viscosity in seconds.
  4. 4. The curable composition of claim 1 wherein in unit formula (A-III), each R M is independently an alkyl group of 1 to 6 carbon atoms and subscript e is sufficient to provide the hydroxyl-terminated polydiorganosiloxane gum with a plasticity of 30 mils (0.76 mm) to 70 mils (1.78 mm).
  5. 5. The curable composition of claim 1, wherein in unit formula (B-II), each R M is independently an alkyl group of 1 to 6 carbon atoms, each Z is OH, and the amount (Z '+o') has a value sufficient to provide the unblocked resin (B2) with a number average molecular weight of 2,900g/mol to 5,000 g/mol.
  6. 6. The curable composition of claim 1 wherein the hydroxyl terminated polydiorganosiloxane gum (A3) is present at a concentration of 17.67 to 36.2 weight percent based on the combined weight of components (a), (B), (C), (D), and (E).
  7. 7. The curable composition according to claim 1, wherein the polydiorganosiloxane component (a) comprises 5 to 16 wt% of the aliphatic unsaturated polydiorganosiloxane polymer (A1) and 20 to 30 wt% of the hydroxyl-terminated polydiorganosiloxane gum (A3), wherein the weight percentages are relative to the combined weight of components (a), (B), (C), (D) and (E), the content of vinyl groups in the curable composition is 0.03 to 0.08 wt%, the weight ratio of the unblocked resin (B2) to the blocked resin (B1) is 0.55 to 5, and the molar ratio of silicon-bonded hydrogen atoms to vinyl groups is 10 to 30.
  8. 8. A process for preparing the curable composition of any one of claims 1 to 7, the process comprising: i) Mixing the hydroxyl-terminated polydiorganosiloxane gum (A3), the uncapped resin (B2) and the condensation catalyst (E), and Ii) further mixing the resulting mixture obtained from step i) with the aliphatic unsaturated polydiorganosiloxane polymer (A1), the end-capping resin (B1), the polyorganosiloxane (C) and the hydrosilylation reaction catalyst (D), thereby forming the curable composition.
  9. 9. An adhesive article comprising a substrate and a silicone pressure sensitive adhesive on at least one surface of the substrate, wherein the silicone pressure sensitive adhesive is a cured product of the curable composition of any one of claims 1 to 7.
  10. 10. A method of making an adhesive article, the method comprising: Optionally (1) treating the surface of the substrate, (2) Applying a curable composition according to any one of claims 1 to 7 on at least one surface of the substrate, and (3) Curing the curable composition.

Description

Curable composition for silicone pressure sensitive adhesives Technical Field The present invention relates to curable compositions and methods of making the curable compositions. In particular, the present invention relates to hydrosilylation and condensation curable compositions that cure to form silicone pressure sensitive adhesives. Background Protective films and carrier tapes are two major applications of silicone pressure sensitive adhesives in the electronics manufacturing industry. In general, during the manufacture of electronic devices, various components of protective films and carrier tapes are laminated together with adherends to form a plurality of layers, and it is important that the layers adhere to each other and are not subject to damage leading to failure of the components. The plurality of layers typically include a protective film that adheres to an adherend (e.g., a graphite sheet, copper foil, or ultra-thin double-sided tape) used in the manufacture of the electronic device to protect the adherend from scratches and other damage during processing and/or transportation. Such protective films are expected to cleanly peel from the adherend, e.g., leaving no residue discernable to the end user of the electronic device, which typically requires the protective film to have low adhesion to the adherend, such as less than 10 grams per inch of adhesion to stainless steel according to ASTM D3330. However, such low adhesion silicone protective films may have the disadvantage of being difficult to form fast and strong adhesion to other layers when manufacturing consumer electronic devices. Accordingly, there is a need in the industry for a silicone pressure sensitive adhesive that is capable of adhering to a low adhesion silicone protective film with desirable adhesive properties. Disclosure of Invention The present invention provides a novel curable composition that cures into a cured product that achieves high adhesion (i.e.,. Gtoreq.400 grams per inch (g/in)) to low adhesion silicone protective films. "Low adhesion silicone protective film" refers to a protective film having a low adhesion silicone pressure sensitive adhesive that is different from the silicone pressure sensitive adhesive of the present invention and has an adhesion to stainless steel of <10g/in. Adhesion properties were measured according to ASTM D3330 using an adhesion/peel tester of AR 1500. The curable compositions of the present invention comprise a novel combination of aliphatic unsaturated polydiorganosiloxane polymers, hydroxyl terminated polydiorganosiloxane gums, terminated polyorganosiloxane resins, uncapped polyorganosiloxane resins, polyorganosiloxane, hydrosilylation catalysts, and condensation catalysts in specific concentrations. The curable compositions of the present invention are particularly suitable for forming silicone pressure sensitive adhesives. The curable composition may be cured via both hydrosilylation and condensation reactions (i.e., hydrosilylation and condensation reaction curable compositions) to produce pressure sensitive adhesives (also known as "hydrosilylation/condensation dual cure PSAs"). In a first aspect, the present invention is a curable composition comprising: (A) A polydiorganosiloxane component, the polydiorganosiloxane component, the polydiorganosiloxane component comprises: (A1) From greater than 3.1% to 20% by weight of an aliphatic unsaturated polydiorganosiloxane polymer of formula (a-I): RM(3-c)RUcSiO-(RURMSiO)a-(RM2SiO)b-SiRUdRM(3-d) (A-I) wherein each R M is independently selected from the group consisting of monovalent hydrocarbon groups of 1 to 30 carbon atoms free of aliphatic unsaturation and monovalent halogenated hydrocarbon groups free of aliphatic unsaturation, each R U is independently an alkenyl group, and the indices a, b, c, and d have an average value such that a≥0, b≥0, c is zero or 1, d is zero or 1, the number (a+b) is 100 to 2000, and the number (a+c+d) is≥2, and (A3) Hydroxyl-terminated polydiorganosiloxane gums of unit formula (a-III): {(HO)RM2SiO1/2}2(RM2SiO2/2)e (A-III) Wherein each R M is independently selected from the group consisting of a monovalent hydrocarbon group of 1 to 30 carbon atoms free of aliphatic unsaturation and a monovalent halogenated hydrocarbon group free of aliphatic unsaturation, and subscript e has a value sufficient to impart (A3) a plasticity of 20 mils (0.51 mm) to 80 mils (2.03 mm) to the hydroxy-terminated polydiorganosiloxane gum, wherein plasticity is measured by applying A1 kg load to a spherical sample having a weight of 4.2g at 25 ℃ for 3 minutes based on ASTM D926 and the results are measured in thousandths of an inch (mil) and the procedure is based on ASTM D926, which is present in an amount that provides a weight ratio of the hydroxy-terminated polydiorganosiloxane gum (A3) to the aliphatic unsaturated polydiorganosiloxane polymer (A1) of 0.89:1 to 9.33:1; (B) A component of a polymeric organosilicate resin, the p