Silicone hybrid pressure sensitive adhesive and methods for its preparation and use on uneven surfaces

A silicone hybrid pressure sensitive adhesive composition comprises:

• 100 parts by weight of (A) a linear, or substantially linear, polydiorganosiloxane having reactive groups comprising a silicon bonded (meth)acryloxyalkyl-functional group in a pendant position and optionally a silicon bonded aliphatically unsaturated hydrocarbon group in a terminal position, wherein starting material (A) comprises unit formula
• MpM″qDmD′nD″oT″rQs, where
• M represents a unit of formula (R13SiO1/2),
• M″ represents a unit of formula (R12R3SiO1/2),
• D represents a unit of formula (R12SiO2/2),
• D′ represents a unit of formula (R1R2SiO2/2),
• D″ represents a unit of formula (R1R3SiO2/2),
• T′″ represents a unit of formula (R5SiO3/2), and
• Q represents a unit of formula (SiO4/2), where
• each R1 is a monovalent hydrocarbon group free of aliphatic unsaturation,
• each R2 is the (meth)acryloxyalkyl functional group,
• each R3 is the aliphatically unsaturated monovalent hydrocarbon group,
• each R5 is independently selected from the group consisting of R1, R2, and R3, and
• subscripts p, q, m, n, o, r, and s have values such that
• 0≤p, 0≤q, 0≤o, a quantity (p+q)≥2, a quantity (q+o)≥2
• 0<m<10,000, 2<n≤10,000, o≥0, a quantity (m+n+0) is 100 to 10,000,
• a ratio (m+o)/n is 1/1 to 500/1,
• a ratio (q+o)/(m+n) is 0≤ to 1/5,
• 0≤ r≤100, and
• 0≤ s≤100,
• a ratio (m+n+o)/(r+s) is 50/1 to 10,000/1 if 0<r or if 0<s;
• (B) a polyorganosilicate resin in an amount sufficient to provide a weight ratio of the polyorganosilicate resin to (A) the polydiorganosiloxane (Resin/Polymer Ratio) of 0.15/1 to 4/1, where the polyorganosilicate resin comprises unit formula MaM″bM′″cDdD′eT′″fQhXi, where M″, D, D′, T, and Q are as described above, M′″ represents a unit of formula (R12R2SiO1/2), where R1 and R2 are as described above, X represents a hydroxyl group, and subscripts a, b, c, d, e, f, h, and i, have values such that
• a≥0, b≥0, c≥0 and a quantity (a+b+c)>10 mole %;
• d≥0, e≥0, and a quantity (d+e) is 0 to a number sufficient to provide 30 mole % of D units and D′ units combined to the resin;
• f≥0, with the proviso that subscript f has a maximum value sufficient to provide 40 mole % of T′″ units to the resin;
• h>0, with the proviso that subscript h has a value sufficient to provide 30 mole % to 70 mole % of Q units to the resin;
• a+b+c+d+e+f+h=100 mole %;
• i≥0 is not included in the molar ratio, with the proviso that subscript i has a maximum value sufficient to provide 5 mole % of hydroxyl groups to the resin
• (C) a polyorganohydrogensiloxane comprising unit formula MtMHuDvDHwTxTHyQz,
• where M, D, T, and Q represent units of the formulas shown above, and
• MH represents a unit of formula (HR12SiO1/2),
• DH represents a unit of formula (HR1SiO2/2),
• T represents a unit of formula (R1SiO3/2),
• TH represents a unit of formula (HSiO3/2), and
• subscripts t, u, v, w, x, y, and z have values such that t≥0, u≥0, v≥0, w≥0, x≥0, y≥0, z≥ 0, a quantity (u+w+y)≥2, and a quantity (t+u+V+W+x+y+z) is sufficient to give the polyorganohydrogensiloxane a viscosity of 3 mPa·s to 1,000 mPa·s at 25° C.;
• with the provisos that starting materials (A), (B), and (C), and amounts of each, are sufficient to provide:
• i) a molar ratio of silicon bonded hydrogen atoms in starting material (C) to aliphatically unsaturated monovalent hydrocarbon groups R3 in starting materials (A) and/or (B) (SiH/Vi ratio) of >0.2/1,
• ii) a molar ratio of silicon bonded hydrogen atoms in starting material (C) to reactive groups in starting materials (A) and/or (B) (SiH/reactive group ratio) of <0.34, where the reactive groups are R2 and R3 combined;
• (D) a hydrosilylation reaction catalyst in an amount sufficient to provide 2 ppm to 500 ppm of platinum based on combined weights of starting materials (A), (B), and (C);
• 0.1 weight % to 10 weight %, based on combined weights of starting materials (A), (B), and (C), of (E) a photoradical initiator;
• 10 ppm to 5,000 ppm, based on combined weights of starting materials (A), (B), and (C), of (F) a hydrosilylation reaction inhibitor;
• 5 ppm to 2,000 ppm, based on combined weights of starting materials (A) and (B), of (G) a free radical scavenger;
• 0 to 90 weight %, based on combined amounts of all starting materials in the composition, of (H) a solvent;
• 0 to 5 weight % based on combined weights of starting materials (A) and (B), of (I) an additive selected from the group consisting of a sensitizer and a synergist;
• and
• 0 to 30 weight % based on combined weights of starting materials (A) and (B), of (J) filler selected from the group consisting of a fumed silica or participated silica.