Optically clear silicone acrylate adhesive composition

Abstract

The composition comprises: (a) 10 to 90 weight percent of an organopolysiloxane resin; and (b) 10 to 90 weight percent of a (meth)acrylate component consisting of (i) at least one monofunctional (meth)acrylate containing an ether group and / or a hydroxyl group, and optionally (ii) at least one monofunctional (meth)acrylate containing an alkyl group and free of ether groups and hydroxyl groups, wherein the molar ratio of (ii) to (i) is in the range of 0:1 to 22:1, and the (meth)acrylate component is free of hydroxyl groups. When the composition contains a monofunctional (meth)acrylate containing an ether group, it also contains, as part of component (i), at least one monofunctional (meth)acrylate containing an ether group, and / or component (ii) a (meth)acrylate component containing a monofunctional (meth)acrylate containing an alkyl group and not containing an ether group or a hydroxyl group, (c) 0.11 to 11 mass percent of a crosslinking agent, and (d) 0.1 to 10 mass percent of a photoradical initiator, wherein the mass percentages are based on the total mass of components (a) to (c).

Description

[Technical Field]

[0001] The present invention relates to curable silicone-based compositions that cure under exposure to ultraviolet light to form optically clear adhesive materials.

[0002] Introduction Light-curable optically clear adhesives, particularly light-curable liquid optically clear adhesives, have applications in optical bonding for electronic devices such as optical displays. The light-curable optically clear adhesives optically bond elements in display applications, and the optically bonded elements can include display panels, glass plates, touch panels, diffusers, stiffness compensation devices, heaters, and flexible films such as polarizers and retarders.

[0003] (Meth)acrylate materials are common in photocurable adhesives. However, (meth)acrylate compositions tend to shrink when they cure, especially when a large amount of acrylate monomer is present to keep the composition viscosity low enough to facilitate inkjet printing of the composition. Shrinkage corresponds to dimensional instability, which is undesirable in adhesives because it can lead to the adhesive pulling away from or delaminating the elements it is adhering to. Adding a plasticizer to a (meth)acrylate composition can reduce the shrinkage of the composition during curing, but it is known that the composition retains residual plasticizer, which is often undesirable. Therefore, it is desirable to avoid the use of plasticizers.

[0004] Identifying a (meth)acrylate composition that functions as a photocurable adhesive with a viscosity in the range of 10 to 100,000 millipascal-seconds (mPa·s) at 25 degrees Celsius (°C), preferably at least 10 mPa·s at 25°C, while simultaneously having a viscosity of 50 mPa·s or less at 60°C, making it suitable for inkjet applications, and that, after photocuring, has greater than 90% transparency at 550 nanometers through a 1-millimeter-thick film of the cured composition, a shear storage modulus in the range of 1 to 5,000 kilopascals (kPa) at 1 hertz and 1% shear rate over 25 to 80°C, a peel adhesion to polyethylene terephthalate (PET) of greater than 38.6 Newtons / meter (greater than 100 grams-force / inch), and undergoes less than 8% shrinkage upon cure as described herein below, would advance the art of photocurable optically clear adhesives. Achieving these properties without the use of plasticizers is particularly desirable. Summary of the Invention

[0005] The present invention solves the problem of providing a photocurable, optically clear adhesive in the form of a (meth)acrylate composition having a viscosity in the range of 10 to 100,000 millipascal-seconds (mPa·s) at 25 degrees Celsius (°C), and even a viscosity of at least 10 mPa·s at 25°C, while at the same time having a viscosity of 50 mPa·s or less at 60°C, and thus suitable for inkjet applications, which, after photocuring, has greater than 90% transparency at 550 nanometers through a 1-millimeter thick film of the cured composition, a storage modulus in the range of 1 to 5,000 kilopascals (kPa) at 1 hertz and 1% shear rate over a range of 25 to 80°C, a peel adhesion to PET greater than 38.6 Newtons / meter (greater than 100 grams-force / inch), and undergoes less than 8% shrinkage upon curing as described herein below. It has been discovered that the compositions of the present invention can achieve these properties without the use of plasticizers. It has also been discovered that the compositions of the present invention can be inkjet-jettable.

[0006] The present invention is the result of the surprising and unexpected discovery that the inclusion of an organopolysiloxane resin containing at least 50 mole percent (mol %) "T" siloxane units in the (meth)acrylate photocurable composition of the present invention, wherein the molar ratio of alkyl groups to aryl groups in the organopolysiloxane resin is in the range of 0:1 to 4:1, and the concentration of silicon-bonded hydroxyl and alkoxyl groups (collectively "OZ" groups) in the organopolysiloxane is in the range of 0 to 100 mole percent, based on moles of organopolysiloxane resin, functions as an adhesion promoter, enabling the aforementioned problems to be solved. Particularly surprising is the fact that the organopolysiloxane resin reduces shrinkage of the composition upon cure.

[0007] In a first aspect, the present invention provides a composition comprising the following components: (a) 10 to 90 weight percent organopolysiloxane resin containing at least 50 mole percent T siloxane units, wherein the molar ratio of alkyl groups to aryl groups in the organopolysiloxane resin is in the range of 0:1 to 4:1; and (b) 10 to 90 weight percent (meth)acrylate component consisting of (i) at least one monofunctional (meth)acrylate containing an ether group and / or a hydroxyl group, and optionally (ii) at least one monofunctional (meth)acrylate containing an alkyl group and free of ether groups and hydroxyl groups, wherein the molar ratio of (ii) to (i) is in the range of 0:1 to 22:1; When the meth)acrylate component contains a monofunctional (meth)acrylate containing a hydroxyl group, it also contains, as part of component (i), at least one monofunctional (meth)acrylate containing an ether group, and / or component (ii) a monofunctional (meth)acrylate containing an alkyl group and no ether group or hydroxyl group, (c) 0.1 to 11 mass percent of a crosslinking agent having an average of at least two ethylenically unsaturated double bonds per molecule, and (d) 0.1 to 10 mass percent of a photoradical initiator, wherein the mass percents are based on the total mass of components (a) to (c), and the mass percents of components (a) to (c) add up to 100 mass percent.

[0008] In a second aspect, the invention provides a process comprising using the composition of the first aspect as an adhesive, the process comprising applying the composition onto a first object and then applying a second object to the composition to sandwich the composition between the first and second objects in contact therewith.

[0009] The compositions of the present invention can be useful as optically clear adhesives. DETAILED DESCRIPTION OF THE INVENTION

[0010] Test methods, unless a date is given with the test method number, refer to the test method most recent as of the priority date of this document. Reference to a test method includes both a reference to the testing society and the test method number. The following test method abbreviations and designations apply herein: ASTM refers to the American Society for Testing and Materials, EN refers to European Norm, DIN refers to Deutsches Institut fur Normung, JIS refers to Japanese Industrial Standard, and ISO refers to the International Organization for Standards.

[0011] Products identified by trade names refer to compositions available under those trade names as of the priority date of this document.

[0012] "Plurality" means two or more. "And / or" means "and, or alternatively." All ranges are inclusive unless otherwise indicated. Identification of materials by trademark or trade name refers to materials having compositions sold under that trademark or trade name as of the priority date of this specification.

[0013] General term “C x-y "," "C x -C y "," "Cx-Cy," and "Cx-Cy" are interchangeable in the context of chemical structures and refer to having x to y carbon atoms in the chemical structure.

[0014] Molecular weights herein, when referring to polymers, refer to weight-average molecular weight (Mw). Polymer Mw was determined using gel permeation chromatography (GPC) using a Waters 2695 Separation Module equipped with a Waters 2487 ultraviolet (UV) detector, with three STYRAGEL™ HR columns (7.8 x 300 mm, molecular weight separation range 100-4,000,000) and a STYRAGEL™ guard column (7.8 x 200 mm) with THF. STYRAGEL is a trademark of Millipore Corporation. Samples were prepared as 0.5 weight percent (wt%) solutions in toluene and filtered through 0.45 micrometer polytetrafluoroethylene syringe filters. A flow rate of 1 milliliter per minute, column and detector temperatures of 35 degrees Celsius (°C), an injection volume of 100 microliters, and a run time of 60 minutes were used. Mw was calculated relative to linear polystyrene standards covering the molecular weight range of 580-2,610,000.

[0015] "(Meth)acryloyloxy group" refers to an acryloyloxy group and / or a methacryloyloxy group. An acryloyloxy group has the chemical structure: H2C=CH-C(O)O-. A methacryloyloxy group has the chemical structure: H2C=C(CH3)-C(O)O-.

[0016] "Siloxane" refers to a molecule containing at least one siloxane (Si-O-Si) bond. As used herein, "siloxane" may refer to a "polysiloxane" having multiple siloxane bonds or a siloxane having only one siloxane bond. The term "polysiloxane" is used to refer to a siloxane having two or more siloxane bonds. Polysiloxanes can have chain, ring, ladder, and three-dimensional network structures.

[0017] Polysiloxanes contain multiple siloxane units linked together through siloxane bonds. The siloxane units can be characterized by the designations M, D, T, or Q. There are two commonly accepted uses of the MDTQ nomenclature: the GE method and the NMR method. The use herein follows the NMR method. Unless otherwise specified, "M" represents R3SiO 1 / 2 It corresponds to the siloxane unit. "D" is R2SiO 2 / 2 and R2(OZ)SiO 1 / 2 It corresponds to the combination of siloxane units. "T" is RSiO 3 / 2 , R(OZ)SiO 2 / 2 , and R(OZ)2SiO 1 / 2 The "Q" corresponds to the combination of siloxane units. (OZ)3SiO 1 / 2 , (OZ)2SiO 2 / 2 , (OZ)SiO 3 / 2 , and SiO 4 / 2 corresponds to a combination of siloxane units. Each "R" is independently selected from hydrocarbyl groups and may be alkyl or aryl. Preferably, R is selected from the group consisting of C1-C8 alkyl (such as methyl, ethyl, propyl, methyl, butyl, pentyl, hexyl, heptyl, and octyl), and C6-C20 aryl (including phenyl and benzyl). "OZ" is -OH or -OR, where R is as defined above.

[0018] In particular, oxygen atoms with a multiple of the subscript "1 / 2" are siloxane-bonded oxygen atoms shared with the silicon atoms of two siloxane units that comprise one of the siloxane units of interest. The subscript numerator indicates how many shared oxygen atoms are bonded to the silicon atom. For example, SiO 3 / 2 has three siloxane-bonded oxygen atoms.

[0019] The M, D, and T designations can include a superscript to indicate which R group is attached to the silicon atom of the siloxane unit. If no superscript designation is used, the R groups are assumed to be all methyl groups. For example, T Pr refers to a T unit where the R group is an n-propyl group.Ph The unit refers to a T unit, where the R group is a phenyl group. MA The unit refers to a T unit in which the R group is a (meth)acryloyloxypropyl group. Me,Me and D Me Each 2 refers to a D unit having two methyl R groups on the silicon atom. Ph,Me and D Ph Both refer to a D unit having one phenyl R group and one methyl R group on the silicon atom. Ph、Ph and D Ph 2 both refer to D units with two phenyl R groups on the silicon atom. Me、Me、Me and M Me Both 3's refer to M units, which have three methyl R groups on the silicon atom.

[0020] Chemical formula representations of polysiloxanes using the M, D, T, and Q designations typically have subscripts associated with the unit identifiers that can refer to either the average molar ratio of that siloxane unit to all siloxane units in the molecule or the average number of related siloxane units in the molecule. When the subscript associated with a siloxane unit is 1 or greater, the subscript refers to the average number of those siloxane units in the molecule. When the subscript associated with a siloxane unit is less than 1, the subscript refers to the average molar ratio of that siloxane unit to the moles of all siloxane units in the molecule. The absence of a subscript means that the value of the subscript is 1.

[0021] "Organopolysiloxane" refers to a polysiloxane having at least one organic group bonded to a silicon atom of the polysiloxane.

[0022] "Optically transparent" or "optical clarity" refers to a material that has at least 90 percent transmittance at a wavelength of 550 nanometers when measured through a 1.0 millimeter thick film of the material. Transmittance is measured as described in the Examples section below.

[0023] The composition of the present invention includes (a) an organopolysiloxane resin, (b) a (meth)acrylate component, (c) a crosslinking agent, and (d) a photoradical initiator.

[0024] The organopolysiloxane resin contains at least 50 mole percent "T" siloxane units, and may contain 50 mole% or more, 60 mole% or more, 70 mole% or more, or even 80 mole% or more, based on all siloxane units in the organopolysiloxane resin, while at the same time typically contains no more than 100 mole%, no more than 90 mole%, no more than 80 mole%, no more than 75 mole%, no more than 70 mole%, or even no more than 60 mole% T siloxane units.

[0025] The molar ratio of alkyl groups to aryl groups in the organopolysiloxane resin may be 0:1 or greater, 0.1:1 or greater, 0.2:1 or greater, 0.4:21 or greater, 0.7:1 or greater, 1:1 or greater, 1.2:1 or greater, 1.5:1 or greater, 2.0:1 or greater, 2.5:1 or greater, 3.0:1 or greater, or even 3.5:1 or greater, while typically being 4.0:1 or less, 3.5:1 or less, 3.0:1 or less, 2.5:1 or less, 2:1 or less, 1.5:1 or less, 1.2:1 or less, 1.1:1 or less, 1.0:1 or less, 0.7:1 or less, 0.4:1 or less, 0.2:1 or less, or even 0.1:1 or less. Desirably, the alkyl groups are each independently selected from C1-C8 alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, and octyl groups. Preferably, the aryl group is selected from C6 to C20 aryl groups, including aryl and phenyl.

[0026] Desirably, the organopolysiloxane resin has an OZ concentration of 0 mol% or greater, and can be 5 mol% or greater, 10 mol% or greater, 20 mol% or greater, 30 mol% or greater, 40 mol% or greater, 50 mol% or greater, 50 mol% or greater, 60 mol% or greater, 70 mol% or greater, 80 mol% or greater, or even 90 mol% or greater, based on moles of organopolysiloxane resin, while at the same time typically being 100 mol% or less, and can be 90 mol% or less, 80 mol% or less, 70 mol% or less, 60 mol% or less, 50 mol% or less, 40 mol% or less, 30 mol% or less, 20 mol% or less, or even 10 mol% or less. Desirably, the OZ groups are hydroxyl groups.

[0027] 29 Si, 13 C, and 1 H nuclear magnetic resonance spectroscopy is used to measure the molar ratio of alkyl groups to aryl groups in organopolysiloxane resins and the OZ concentration (see, for example, The Analytical Chemistry of Silicones, Smith, A. Lee, ed., John Wiley & Sons: New York, 1991, p. 347ff.).

[0028] The organopolysiloxane resin may have the average chemical formula (I): M a D b T c Q d (I) During the ceremony, the subscript a is the molar ratio of M siloxane units to all siloxane units in the organopolysiloxane resin and has an average value of 0 or greater, and may have an average value of 0.10 or greater, 0.15 or greater, 0.20 or greater, or even 0.25 or greater, while simultaneously typically having an average value of 0.35 or less, and may be 0.30 or less, 0.28 or less, 0.25 or less, 0.20 or less, or even 0.15 or less; The subscript b is the molar ratio of D siloxane units to all siloxane units in the organopolysiloxane resin and has an average value of 0 or greater, and may have an average value of 0.10 or greater, 0.15 or greater, 0.20 or greater, or even 0.25 or greater, while at the same time typically has an average value of 0.35 or less, and may be 0.30 or less, 0.25 or less, 0.20 or less, or even 0.15 or less. the subscript c is the molar ratio of T siloxane units to total siloxane units in the organopolysiloxane resin, and has an average value of 0.50 or greater, and may have an average value of 0.60 or greater, 0.70 or greater, 0.80 or greater, or even 0.90 or greater, while simultaneously typically having an average value of 1.00 or less, or even 0.90 or less, 0.80 or less, 0.70 or less, or even 0.60 or less; the subscript d is the molar ratio of Q siloxane units to all siloxane units in the organopolysiloxane resin and has an average value of 0 or greater, and may have an average value of 0.10 or greater, 0.15 or greater, 0.20 or greater, 0.25 or greater, 0.30 or greater, or even 0.35 or greater, while simultaneously typically having an average value of 0.50 or less, 0.40 or less, 0.30 or less, 0.25 or less, 0.20 or less, or even 0.15 or less; The sum of the subscripts a+b+c+d is equal to 1.00, and The molar ratio of alkyl groups to aryl groups and the concentration of OZ are as described above for organopolysiloxane resin 8 / 6.

[0029] Preferably, the ratio of subscript a / c is in the range of 0 to 0.5, the ratio of subscript b / c is in the range of 0 to 0.5, and the ratio of subscript d / c is in the range of 0 to 0.8.

[0030] The organopolysiloxane resin typically has a Mw of 1,000 or greater, preferably 1200 or greater, and even more preferably 1500 or greater, while simultaneously typically having a Mw of 100,000 or less, preferably 10,000 or less, and more preferably 5,000 or less.

[0031] Methods for preparing suitable organopolysiloxane resins are well established in the art and generally involve hydrolyzing an organosilane having three hydrolyzable groups, such as halogen or alkoxy groups, on the silicone atom in an organic solvent. Suitable organopolysiloxane resins are also commercially available, including those available under the following trade names: DOWSIL® RSN-0233 flake resin, DOWSIL® RSN-0249 flake resin, DOWSIL® RSN-0255 flake resin, DOWSIL® RSN-6018 resin intermediate, DOWSIL® RSN-0805 resin, SILRES® SY300, SILRES® REN168, and SILRES®604. DOWSIL is a trademark of The Dow Chemical Company. SILRES® is a trademark of Wacker-Chemie AG.

[0032] Examples of suitable organopolysiloxane resins include any one or any combination of two or more selected from those generally having the following average chemical formula, recognizing that the subscripts ("Ph" refers to phenyl, "Me" refers to methyl, and "Pr" refers to n-propyl) are: T having an OZ content of 5.0 wt. % OH based on the weight of the organopolysiloxane resin (36 mol % relative to the molar resin), an average Mw of 2,900 g / mol, and a molar ratio of alkyl to aryl groups of 0.43:1. Ph 70 T Pr 30 ; D having an OZ content of 7.1 wt. % OH based on the weight of the organopolysiloxane resin (46 mol % relative to the molar resin), an average Mw of 2,500 g / mol, and a molar ratio of alkyl to aryl groups of 0.77:1 Ph、Me 0.05 D Ph、Ph 0.10 T Me 0.45 T Ph 0.40 and the ratio of the subscript b / c is 0.2; D having an OZ content of 6.5 wt. % OH based on the weight of the organopolysiloxane resin (38 mol % relative to the molar resin), an average Mw of 3,055 g / mol, and a molar ratio of alkyl to aryl groups of 1.6:1 Me、Me 0.15 T Me 0.40 T Ph 0.45 and the ratio of the subscript b / c is 0.2; T having an OZ content of 8.5 wt. % OH based on the weight of the organopolysiloxane resin (70 mol % relative to the molar resin), an average Mw of 2,660 g / mol, and a molar ratio of alkyl groups to aryl groups of 0:1. Ph 1.00 ; D having an OZ content of 6.0 wt. % OH based on the weight of the organopolysiloxane resin (49 mole % relative to mole resin), an average Mw of 3,294 g / mole, and a molar ratio of alkyl to aryl groups of 0.5:1 Me、Me 0.15 D Ph、Ph 0.05 T Me 0.10 T Ph 0.70 and the ratio of the subscript b / c is 0.3; An OZ content of 0.0 wt. % based on the weight of the organopolysiloxane resin, an average Mw of 3,719 / mol, and a molar ratio of alkyl to aryl groups of 2.3:1. Me,Me,Me 0.28 T Pr 0.25 T Ph 0.48 and the ratio of the subscript a / c is 0.4; T having an OZ content of 7.4 wt. % OH based on the weight of the organopolysiloxane resin (38 mol % relative to the molar resin), an average Mw of 1,614 g / mol, and a molar ratio of alkyl groups to aryl groups of 0:1. Ph 0.65 Q 0.35 where the ratio of the subscript d / c is 0.5; and An OZ content of 5.2 wt. % OH based on the weight of the organopolysiloxane resin (24 mol % relative to the moles of resin), an average Mw of 3,277 g / mol, and a molar ratio of alkyl to aryl groups of 0.68:1. Me,Me,Me 0.12 T Ph 0 .53 Q 0.35 where the ratio of subscript a / c is 0.2 and the ratio of subscript d / c is 0.7.

[0033] The concentration of organopolysiloxane resin in the composition can be 10% by weight or more, 20% by weight or more, 30% by weight or more, 40% by weight or more, 50% by weight or more, 60% by weight or more, 70% by weight or more, or even 80% by weight or more, while at the same time, it is typically 90% by weight or less, 80% by weight or less, 70% by weight or less, 60% by weight or less, 50% by weight or less, 40% by weight or less, 30% by weight or less, or even 20% by weight or less, based on the total weight of (a) organopolysiloxane resin, (b) (meth)acrylate component, and (c) crosslinker. If the concentration of organopolysiloxane resin is insufficient, the cured product will not have adequate adhesive strength and will shrink by more than 8%. If the concentration of organopolysiloxane is too high, the cured product will have undesirable hardness.

[0034] The composition of the present invention further comprises a (meth)acrylate component consisting of (i) at least one monofunctional (meth)acrylate containing an ether group and / or a hydroxyl group, and optionally (ii) at least one monofunctional (meth)acrylate containing an alkyl group and free of ether groups and hydroxyl groups. The molar ratio of (ii):(i) can be 0:1 or more, 0.2:1 or more, 0.5:1 or more, 1:1 or more, 2:1 or more, 3:1 or more, 4:1 or more, 5:1 or more, 6:1 or more, 7:1 or more, 8:1 or more, or even 9:1 or more, while typically being 22:1 or less, 21:1 or less, 20:1 or less, 19:1 or less, 15:1 or less, 10:1 or less, 9:1 or less, 8:1 or less, 7:1 or less, 6:1 or less, 5:1 or less, 4:1 or less, 3:1 or less, 2:1 or less, 1:1 or less, 0.5:1 or less, or even 0.2:1 or less.

[0035] It is desirable for the compositions of the present invention to cure into optically transparent materials. Monofunctional (meth)acrylates containing ether and / or hydroxyl groups are necessary to achieve high light transmittance through the cured composition. However, it has been surprisingly discovered that to achieve optical transparency when using a monofunctional (meth)acrylate containing a hydroxyl group in (i), the composition must also contain a monofunctional (meth)acrylate containing an ether group and / or an alkyl group, but not an ether or hydroxyl group. Nevertheless, the (meth)acrylate component may contain a monofunctional (meth)acrylate containing an ether group, either alone or in combination with a monofunctional (meth)acrylate containing a hydroxyl group and / or an alkyl group, but not an ether or hydroxyl group, and still achieve optical transparency.

[0036] Monofunctional (meth)acrylates containing ether groups and / or hydroxyl groups suitable for use in the (meth)acrylate component include any one, or any combination of two or more, of compounds selected from the group consisting of (meth)acrylate-functional ethylene glycol, (meth)acrylate-functional propylene glycol, (meth)acrylate-functional polyethers including poly(ethylene oxide) and / or poly(propylene oxide), and hydroxyl-functional (meth)acrylate-functional compounds.

[0037] Examples of suitable monofunctional (meth)acrylates containing an ether group include methoxyethoxyethyl acrylate, methoxypolyethylene glycol acrylate, methoxypolypropylene glycol acrylate, phenol ethylene glycol acrylate, phenol diethylene glycol acrylate, phenol tetraethylene glycol, nonylphenyl ethylene glycol acrylate, di(ethylene glycol) 2-ethylhexyl ether acrylate, and nonylphenol dipropylene glycol acrylate, 2-(2-ethoxyethoxy)ethyl acrylate; methoxypolyethene glycol 400 acrylate.

[0038] Examples of suitable monofunctional (meth)acrylates containing a hydroxyl group include hydroxyl-substituted (meth)acrylates, hydroxyethyl acrylate, hydroxypropyl acrylate, and hydroxybutyl acrylate.

[0039] The alkyl group-containing, ether group- and hydroxyl group-free monofunctional (meth)acrylates suitable for use in the (meth)acrylate component can be linear, branched, and / or cyclic.

[0040] Examples of linear alkyl (meth)acrylates containing an alkyl group and no ether group or hydroxyl group include any one or any combination of two or more compounds selected from the group consisting of hydroxypropyl butyl acrylate, butyl methacrylate, n-hexyl acrylate, n-hexyl methacrylate, ethylhexyl acrylate, n-heptyl acrylate, n-heptyl methacrylate, octyl acrylate, dodecyl acrylate, octyl methacrylate, nonyl acrylate, nonyl methacrylate, lauryl acrylate, lauryl methacrylate, cetyl acrylate, cetyl methacrylate, stearyl acrylate, and stearyl methacrylate.

[0041] Examples of branched (meth)acrylates containing an alkyl group and no ether group or hydroxyl group include any one or any combination of two or more of the compounds selected from the group consisting of isononyl acrylate, isooctyl acrylate, isooctyl methacrylate, ethylhexyl acrylate, ethylhexyl methacrylate, 2-methylheptyl acrylate, isononyl methacrylate, isobutyl acrylate, isobutyl methacrylate, and isostearyl acrylate.

[0042] Examples of cyclic (meth)acrylates containing an alkyl group and no ether group or hydroxyl group include any one or any combination of two or more compounds selected from the group consisting of isobornyl acrylate, isobornyl methacrylate, cyclohexyl acrylate, dicyclopentanyl acrylate, 2-norbornyl acrylate, and 2-norbornyl methacrylate.

[0043] The concentration of the (meth)acrylate component in the composition may be 10% by weight or more, 20% by weight or more, 30% by weight or more, 40% by weight or more, 50% by weight or more, 60% by weight or more, 70% by weight or more, or even 80% by weight or more, while at the same time typically is 90% by weight or less, 80% by weight or less, 70% by weight or less, 60% by weight or less, 50% by weight or less, 40% by weight or less, 30% by weight or less, or even 20% by weight or less, based on the combined weight of (a) organopolysiloxane resin, (b) (meth)acrylate component, and (c) crosslinker.

[0044] The compositions of the present invention are desirably inkjet printable, meaning that they can be printed onto a substrate using inkjet printing equipment. To be inkjet printable, the viscosity of the composition must be low enough to function in the inkjet equipment. To function in the inkjet equipment, the composition desirably has a viscosity in the range of at least 10 mPa·s at 25°C, while simultaneously having a viscosity of 50 mPa·s or less at 60°C. A discovery as part of the present invention is that to be inkjet printable, the concentration of the organopolysiloxane resin should be in the range of 10 to 60 wt% of the composition, and simultaneously, the concentration of the (meth)acrylate component should be in the range of 40 to 90 wt% of the composition.

[0045] The composition of the present invention further comprises a crosslinker. The crosslinker has an average of at least two ethylenically unsaturated double bonds per molecule. Desirably, at least one of the ethylenically unsaturated double bonds is part of a (meth)acryloyloxy group. The crosslinker can contain a blend of unsaturated double bonds that are part of a (meth)acryloyloxy group and unsaturated double bonds that are not part of a (meth)acryloyloxy group. Alternatively, all of the ethylenically unsaturated double bonds can be part of a (meth)acryloyloxy group. The crosslinker provides high temperature stability to the cured composition by crosslinking the composition.

[0046] Suitable crosslinking agents include 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, 1,10-decanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, 2-hydroxy 3-methacrylpropyl acrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, pentaerythritol triacrylate, and ethoxylated trimethylolpropane triacrylate. and ethoxylated allyl acrylate.

[0047] The concentration of the crosslinker component in the composition is 0.1% by weight or more, and may be 0.5% by weight or more, 1.0% by weight or more, 2.0% by weight or more, 3.0% by weight or more, 4.0% by weight or more, 5.0% by weight or more, 6.0% by weight or more, 7.0% by weight or more, 8.0% by weight or more, or even 9.0% by weight or more, while at the same time, it is typically 11% by weight or less, 10% by weight or less, 9.0% by weight or less, 8.0% by weight or less, 7.0% by weight or less, 6.0% by weight or less, 5.0% by weight or less, 4.0% by weight or less, 3.0% by weight or less, 2.0% by weight or less, or even 1.0% by weight or less, based on the total weight of (a) organopolysiloxane resin, (b) (meth)acrylate component, and (c) crosslinker. If the crosslinker concentration is insufficient, the cured product will not have high-temperature stability. If the crosslinker concentration is too high, the cured product will be undesirably brittle.

[0048] For the avoidance of doubt, the sum of the weight percent for the combination of (a) organopolysiloxane resin, (b) (meth)acrylate component, and (c) crosslinker, based on the combined weight of (a) organopolysiloxane resin, (b) (meth)acrylate component, and (c) crosslinker, is 100 weight percent.

[0049] The composition of the present invention further comprises a photoradical initiator. Suitable photoradical initiators include ultraviolet (UV) initiators such as any one or any combination of two or more of benzophenone and benzophenone derivatives, acetophenone and acetophenone derivatives, benzoin and its alkyl esters, phosphine oxide derivatives, xanthone derivatives, oxime ester derivatives, and camphorquinone.Suitable commercially available photoinitiators include 2,6-bis(4-azidobenzylidene)cyclohexanone; 2,6-bis(4-azidobenzylidene)-4-methylcyclohexanone; 1-hydroxyl-cyclohexyl-phenyl-ketone (available under the name OMNIRAD™ 184); 2-methyl-1[4-(methylthio)phenyl]-2-morpholinopropan-1-one (available under the name OMNIRAD 907); 2-hydroxy-2methyl-1-phenyl-propan-1-one (available under the name OMNIRAD 1173); 2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-1-propanone (available under the name OMNIRAD 2959); methyl benzoyl formate (OMNIRAD MBF); α,α-dimethoxy-α-phenylacetophenone (available under the name OMNIRAD 651); 2-benzyl-2-(dimethylamino)-1-[4-(4-morpholinyl)phenyl]-1-butanone (available under the name OMNIRAD 369); diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (available under the name OMNIRAD TPO); ethyl(2,4,6-trimethylbenzoyl)phenylphosphinate (available under the name OMNIRAD TPO-L); oxime ester compounds (Adeka and 1-chloro-4-propoxy-9H-thioxanthen-9-one. OMNIRAD is a trademark of IGM Group BV.

[0050] The concentration of the photoinitiator in the composition is typically 0.1% by weight or more, and may be 0.5% by weight or more, 1.0% by weight or more, 2.0% by weight or more, 3.0% by weight or more, 4.0% by weight or more, 5.0% by weight or more, 6.0% by weight or more, 7.0% by weight or more, 8.0% by weight or more, or even 9.0% by weight or more, while at the same time typically is 10% by weight or less, and may be 9.0% by weight or less, 8.0% by weight or less, 7.0% by weight or less, 6.0% by weight or less, 5.0% by weight or less, 4.0% by weight or less, 3.0% by weight or less, 2.0% by weight or less, or even 1.0% by weight or less, based on the combined weight of (a) organopolysiloxane resin, (b) (meth)acrylate component, and (c) crosslinker.

[0051] The composition of the present invention may optionally contain any one additional component or any combination of two or more additional components, or may not contain any one additional component or any combination of two or more additional components.For example, an additional acrylate monomer having a silicon atom may be present in the composition.Examples of such acrylate monomers include 3-[dimethoxy(methyl)silyl]propyl acrylate, trimethylsilyl methacrylate, trimethylsilyl acrylate, triisopropylsilyl acrylate, 3-(methoxydimethylsilyl)propyl acrylate, (trimethoxysilyl)methyl methacrylate, 3-(trimethyloxysilyl)propyl acrylate, 3-(trimethoxysilyl)propyl methacrylate, 3-[dimethoxy(methyl)silyl]propyl methacrylate, 3-(tris(trimethylsilyloxy)silyl)propyl methacrylate, and methacryloxypropyl(tris(trialkylsiloxy)silylethyldimethylsiloxy)silane. The concentration of the additional acrylate monomer is typically 10% by weight or less, and can be 9% by weight or less, 8% by weight or less, 7% by weight or less, 6% by weight or less, 5% by weight or less, 4% by weight or less, 3% by weight or less, 2% by weight or less, 2% by weight or less, 1% by weight or less, 0.5% by weight or less, or even 0.1% by weight or less, and can even be 0% by weight, based on the combined weight of (a) organopolysiloxane resin, (b) (meth)acrylate component, and (c) crosslinker.

[0052] The composition may or may not contain a radical scavenger. Radical scavengers may be desirable to extend the shelf life of the composition by inhibiting curing until the composition is intentionally exposed to UV light. Radical scavengers include phenolic compounds such as 4-methoxyphenol (MEHQ, the methyl ether of hydroquinone), hydroquinone, 2-methylhydroquinone, 2-t-butylhydroquinone, t-butylcatechol, butylated hydroxytoluene, and butylated hydroxyanisole, or any combination of two or more of these. Other types of radical scavengers include phenothiazines and anaerobic inhibitors such as NPAL-type inhibitors (tris-(N-nitroso-N-phenylhydroxylamine) aluminum salts) available from Albemarle Corporation. Typically, the free radical scavenger is present in the composition at a concentration of 0% by weight or greater, 0.001% by weight or greater, 0.01% by weight or greater, or even 0.5% by weight or greater, while at the same time typically being present at a concentration of 1.0% by weight or less, 0.5% by weight or less, or even 0.1% by weight or less, where the weight percent is based on the combined weight of (a) organopolysiloxane resin, (b) (meth)acrylate component, and (c) crosslinker.

[0053] The compositions of the present invention may or may not contain a plasticizer. A plasticizer is a non-reactive ingredient that, when added to a composition, reduces the viscosity of the composition. Desirably, the composition does not contain a plasticizer.

[0054] The composition may contain any one or any combination of two or more of other additional additives, including those selected from UV absorbers, antioxidants, sensitizers (e.g., anthracene derivatives and acridine derivatives), and chain transfer agents. These other additional additives may be present in a total concentration of 0% by weight or more, 0.001% by weight or more, 0.01% by weight or more, or even 0.5% by weight or more, while typically being present in a concentration of 1.0% by weight or less, 0.5% by weight or less, or even 0.1% by weight or less, where the weight percentage is based on the total weight of (a) the organopolysiloxane resin, (b) the (meth)acrylate component, and (c) the crosslinker.

[0055] The present invention also includes a process for using the composition of the present invention. The composition of the present invention is useful as an adhesive material, preferably an inkjet printable and / or optically clear adhesive. In that regard, the process of the present invention for using the composition as an adhesive includes applying the composition onto a first object and then applying a second object to the composition to sandwich the composition between the first and second objects in contact therewith.

[0056] The compositions of the present invention are UV-curable. Desirably, the process of the present invention further comprises curing the composition between the first and second objects by exposing the composition to UV light.

[0057] It may be desirable to pre-cure the composition after application to a first object and before applying a second object. Pre-cure refers to partially curing the composition, for example, by exposing the composition to sufficient UV light to partially cure the composition. Pre-cure can increase the viscosity of the composition, which may be desirable when the composition has a low viscosity that may be desirable for inkjet printing, but a higher viscosity is desired to prevent undesired flow of the composition after it is subsequently applied to the first object. For example, the composition may require a relatively low viscosity to flow easily during application to the first object, but the first object may need to be reoriented (e.g., turned upside down) to apply the second object, and it may be undesirable for the composition to flow on the first object during reorientation. Pre-cure can increase the viscosity of the composition before reorientation to prevent flow during reorientation, but to ensure that the fully uncured composition has sufficient flexibility and conformability to firmly bond to the second object without voids. The degree of pre-cure can be controlled by varying the UV light intensity and / or exposure time used for pre-cure. Increasing either of these increases the degree of pre-curing. If the degree of pre-curing is too low, the pre-cured composition may be deformed too easily and may be squeezed out from between the first and second objects when pressed between them. If the degree of pre-curing is too high, the composition may not be deformable enough to fit the first and second objects, resulting in voids between the composition and at least one of the objects. If the degree of pre-curing is too high, the composition may also have the disadvantage of insufficient adhesion to one or both substrates.

[0058] Desirably, the pre-cure results in a degree of cure in the composition that is 50% or greater, and may be 70% or greater, 75% or greater, 80% or greater, or even 90% or greater, while at the same time being 100% or less, and may be 90% or less, 80% or less, 70% or less, or even 60% or less.

[0059] Using Fourier transform infrared (FTIR) spectroscopy, the composition was measured at 809 or 1408 wavenumbers (cm) in the infrared spectrum. -1 The degree of cure is determined by monitoring the absorption peak intensity of the unsaturated double bond (C=C) that appears at 809 cm. -1 If the peak is difficult to separate, use 1408 cm -1 The peaks are used. Because curing involves reacting unsaturated double bonds, thereby consuming them, the peak intensity at these positions decreases with the degree of cure. The degree of cure is calculated by the following formula: Curing degree (%)=100%[(Ao-Ai) / Ao] (In the formula, Ai = absorption peak intensity of unsaturated double bonds in the composition after UV irradiation; Ao = absorption peak intensity of unsaturated double bonds in the composition before UV irradiation).

[0060] In the broadest scope of the process of the present invention, the composition can be applied to the first object by any means. For example, the following devices are suitable for applying the composition to the first object: gravure coater, offset coater, offset gravure coater, roller coater, reverse roller coater, and printing processes such as screen printing, pin transfer, stencil printing, and inkjet printing. Preferably, an inkjet printer is used to inkjet print the composition onto the first component in the desired pattern.

[0061] The first object and / or the second object can transmit optical light and can be optically transparent. Desirably, at least one of the first object and the second object transmits UV light, and curing of the composition after application of the second object occurs by exposing the composition to UV light through at least one of the first object and the second object.

[0062] Preferably, the composition is UV pre-cured and cured using any one or a combination of two or more wavelengths selected from 365 nanometers (nm), 385 nm, 395 nm, and 405 nm. For optimal control of UV exposure, it is beneficial to use UV light-emitting diode (LED) lamps. Generally, the UV exposure dose is 0.1 Joules per square centimeter (J / cm). 2 ) or more, and is 1.0 J / cm 2 Typically, 200 J / cm 2 less than 100 J / cm 2 The UV exposure of the composition to cure the composition can be carried out in air. However, because oxygen can inhibit curing, UV exposure can preferentially occur in an oxygen-free atmosphere, such as nitrogen or carbon dioxide. [Example]

[0063] Table 1 lists the ingredients for the preparation of the Examples (Examples) and Comparative Examples (Comparative Examples) in this section. "Ph" refers to phenyl, "Me" refers to methyl, "Pr" refers to n-propyl, and "Ma" refers to methacryloyloxypropyl. The "a / c," "b / c," and "a / d" ratios refer to the ratio of the letter subscripts used in formula (I).

[0064] [Table 1-1] [Table 1-2] DOWSIL is a trademark of The Dow Chemical Company. OMNIRAD is a trademark of IGM Group BVBesloten Vennootschap.

[0065] Preparation of A-6 A 500 milliliter (mL) three-neck flask is equipped with a thermometer, a Dean-Stark trap, and a reflux condenser. 158.02 g of A-1 is added to the flask and dissolved in 80.02 g of toluene. Once dissolved, 54.01 g of hexamethyldisilazane (Sigma-Aldrich) and 0.12 g of trifluoroacetic acid (Sigma-Aldrich) are slowly added to the flask. The resulting mixture is stirred at 40 degrees Celsius (°C) for 1 hour. 25.65 g of water is added to the mixture, and the temperature is slowly increased and refluxed for 2 hours. Water and by-products are removed by azeotropic distillation through the Dean-Stark trap. The liquid is cooled to 25°C. Filtered, and the toluene is removed under reduced pressure to yield A-6.

[0066] Preparation of A-7 A 200 mL four-neck flask was equipped with a mechanical stirrer, thermometer, dropping funnel, and reflux condenser. 24.17 g of trimethoxyphenylsilane (Sigma-Aldrich) and 13.67 g of tetraethyl orthosilicate (Sigma-Aldrich) were added. While stirring the mixture in the flask, 1.66 g of concentrated hydrochloric acid and 12.15 g of water were slowly added. Stir for 2 hours, then 25 g of toluene was added. The resulting mixture was treated with 25 g of toluene and 50 g of water and transferred to a separatory funnel. The resulting bottom and top layers were collected, combined, and washed with 50 g of water. The resulting top and bottom layers were again collected, and the water wash was repeated three times. The organic layer was isolated, dried over anhydrous sodium sulfate, and then filtered to give a 21% solution of A-7.

[0067] Preparation of A'-8 A 200 mL four-neck flask was equipped with a mechanical stirrer, thermometer, dropping funnel, and reflux condenser. 1.98 g of hexamethyldisiloxane (Sigma-Aldrich), 21.35 g of trimethoxyphenylsilane (Sigma-Aldrich), and 14.81 g of tetraethyl orthosilicate (Sigma-Aldrich) were added. While stirring the mixture in the flask, 1.66 g of concentrated hydrochloric acid and 11.85 g of water were slowly added. Stir for 2 hours, then add 25 g of toluene. The resulting mixture was treated with 25 g of toluene and 50 g of water and transferred to a separatory funnel. The resulting bottom and top layers were collected, combined, and washed with 50 g of water. The resulting top and bottom layers were again collected, and the water wash was repeated three times. The organic layer was isolated, dried over anhydrous sodium sulfate, and then filtered to give a 23% solution of A'-8.

[0068] Preparation of A'-10 A 200 mL four-neck flask was equipped with a mechanical stirrer, thermometer, dropping funnel, and reflux condenser. 26.97 g of trimethoxyphenylsilane (Sigma-Aldrich) and 11.26 g of OFS-6030 were added. While stirring the mixture in the flask, 1.66 g of concentrated hydrochloric acid and 11.75 g of water were slowly added. Stir for 2 hours, then 25 g of toluene was added. The resulting mixture was treated with 25 g of toluene and 50 g of water and transferred to a separatory funnel. The resulting bottom and top layers were collected, combined, and washed with 50 g of water. The resulting top and bottom layers were again collected, and the water wash was repeated three times. The organic layer was isolated, dried over anhydrous sodium sulfate, and then filtered to give a 42% solution of A'-10.

[0069] Sample Composition Tables 2-4 list the compositions of the example (Ex) and comparative example (CEx) composition samples, along with the amounts of the components listed in grams. Tables 5 and 6 list the characterization of the compositions, including the cured morphology of the compositions.

[0070] For Comparative Examples A-K, components (B), (C), and (D) are mixed with a stirrer for 1 minute at 23° C. For example, prepare Comparative Example A by combining 99 g of component [B(i)-a1], 1 g of component (C-1), and 0.5 g of component (D-1), and then mixing them together with a stirrer for 1 minute at 23° C.

[0071] For Comparative Examples L-T, Examples 1-27, and Example 31, component A (A-1, A-2, A-3, A-4, A-5, A-6, A'-9, A'-11, or A'-12) is dissolved in component (B)(s). Components (C) and (D) are then added to the resulting solution and mixed. For example, Example 1 is prepared by dissolving 50.2 g of component (A-1) in 5.6 g of component [B(i)-a1] and 43.2 g of component [B(ii)-1] with stirring at 23°C for 24 hours. Next, 1.0 g of component (C-1) and 0.5 g of component (D-1) are added to this solution and mixed with a stirrer at 23°C for 1 hour.

[0072] For Comparative Examples U to V and Examples 28 to 29, component A (A-7, A-8, or A'-10), already in solution in an organic solvent, is dissolved in component (B). The organic solvent is then removed under reduced pressure at 40 to 80°C. The mixture is cooled to 23°C, and components (C) and (D) are added to the solution and mixed. For example, to prepare Example 28, 313.3 g of a 21% A-7 solution (65.8 g of A-7) and 33.2 g of [B(i)-a2] are combined in a 1-liter flask. The organic solvent is then removed using a rotary evaporator (50°C, less than 1 torr for 6 hours) under nitrogen bubbling. After cooling to 23°C, 1.0 g of component (C-6) and 1 g of component (D-1) are added to the mixture and mixed with a stirrer at 23°C for 1 hour.

[0073] Characterize each of the samples using the following characterizations: viscosity Determine the dynamic viscosity of each sample using an AR-G2 rheometer equipped with a 40 mm diameter, 2-degree cone-plate measuring system. Test at 25°C and 60°C for 1 minute, 10 seconds. -1A shear rate of 1000 rpm is used. The sample temperature is controlled by a Peltier plate.

[0074] Shear storage modulus To test the shear storage modulus, test specimens of each sample composition are cured. The sample compositions are poured into molds (1 millimeter (mm) thick x 50 mm wide x 50 mm long) and sandwiched between fluoro-coated polyethylene terephthalate films. The sample compositions in the molds are exposed to 365 nm wavelength LED light (FireJet™ FJ100 lamp; FireJet is a trademark of Phoseon Technology, Inc.) at a total UV dose of 6 J / cm. 2 The sample composition is cured by exposure to 1000 K. After the sample composition is cured, the fluorocoated polyethylene terephthalate film is removed and the cured sample is mounted on the parallel plate geometry (25 millimeters) of a rheometer (AtonParr MCR-502). The shear storage modulus (G') is collected at 25°C and 80°C with a strain of 1.0% and a normal stress of 0.5 Newtons at a fixed frequency of 1 Hertz. G' is reported in kilopascals (kPa).

[0075] Transmittance The sample composition was poured into a mold (1 mm thick x 50 mm wide x 50 mm long) and sandwiched between microslide glasses (product #9213, Matsunami Glass Co., Ltd.). The sandwiched sample composition mold was exposed to 365 nm wavelength LED light (FireJet™ FJ100 lamp; FireJet is a trademark of Phoseon Technology, Inc.) with a total UV dose of 6 J / cm. 2 The cured sample composition is cured by exposure to UV-Visible light. The transmittance at 550 nm wavelength through the cured sample composition is measured according to ASTM method D1003 (using a Konica Minolta CM-3600A UV-Visible spectrophotometer, with deionized water as the reference material). The transmittance through the cured sample material is referenced to the transmittance through deionized water to determine the T%.

[0076] Peel adhesion strength The sample composition was coated onto a glass plate to form a 40 micrometer film (100 mm wide and 150 mm long) and exposed to 1.5 J / cm of 365 nm light from an LED lamp (FireJet FJ100). 2 The film is pre-cured by exposure to 365 nm light from an LED lamp at 5 J / cm. A corona-treated polyethylene terephthalate film is placed on the pre-cured film and bonded to the pre-cured film by passing a 2-kilogram rubber-lined pressure roller back and forth across the film twice. 2 The resulting laminate is fully cured by irradiating with an exposure of 0.15 V. The cured laminate is aged at 25°C for 1 day. A 2.54 centimeter wide strip of PET film is formed on the cured composition film by slicing through the PET layer. Using a texture analyzer, the PET film is peeled from the cured composition film by pulling along the length of the PET film strip at an angle of 180° to the original orientation of the PET film at a rate of 5.0 mm / sec. Adhesion strength is reported in units of Newtons per meter (N / m).

[0077] Contraction The gravity cup method was used to measure the specific gravity (SG) of the sample composition at 25°C. L The sample composition is poured into a mold (10 millimeters thick, 20 mm wide, and 40 mm long) and sandwiched between fluoro-coated polyethylene terephthalate films. The sample composition is exposed to 365 nm wavelength LED light (FireJet™ FJ100 lamp; FireJet is a trademark of Phoseon Technology, Inc.) for a total UV dose of 6 J / cm. 2 The fluororesin-coated polyethylene terephthalate film was removed and the specific gravity (SG) of the cured film was measured according to the test method JIS K7112B. S The total shrinkage of the cured composition is determined as a percentage of the pre-cured sample by the following calculation: Shrinkage% = 100% × [(SG S )-(SG L )] / (SG L )

[0078] result Examples (Ex) 1-29 are illustrative of photocurable silicone acrylate compositions of the present invention that provide flowable liquids before curing with viscosities of 14 to 27,000 millipascal-seconds (mPa·s) at 25° C. and 2 to 4,453 mPa·s at 60° C. When the compositions are cured using ultraviolet (UV) light, they are optically clear (greater than 90% T at 1 millimeter thickness), have shear storage moduli (G') greater than 1 kPa and less than 1,157 kPa at 25° C. and greater than 1 kPa and less than 500 kPa at 80° C., peel adhesion strengths ranging from 65 Newtons per meter (N / m) to 1,160 N / m (170 to 3,000 grams-force per inch), and shrinkage less than 8%. Of particular interest are samples having a viscosity of at least 10 mPa·s at 25°C while at the same time having a viscosity of 50 mPa·s or less at 60°C (Examples 1-3, 5-20, 22, 23, 25-27, 30 and 31), because they are suitable for application by inkjet methods.

[0079] Comparative Examples (Comparative) A, C, D, G, and I demonstrate that photocurable silicone compositions containing all of the components of the presently claimed compositions except for the organopolysiloxane resin result in both undesirable bond strength and shrinkage.

[0080] Comparative Examples B and F demonstrate that photocurable silicone compositions containing all of the components of the presently claimed compositions except for the organopolysiloxane resin result in undesirable shrinkage.

[0081] Comparative Examples E, H, J, and K demonstrate that photocurable silicone compositions containing all of the components of the presently claimed compositions except for the organopolysiloxane resin result in undesirable bond strength.

[0082] Comparative Examples L and S demonstrate that photocurable silicone compositions containing all of the components of the presently claimed invention except for the monofunctional (meth)acrylate containing ether and / or hydroxyl groups are unable to achieve optical clarity.

[0083] Comparative Examples M-R demonstrate that photocurable silicone compositions containing all of the components of the presently claimed invention fail to achieve optical clarity (transmittance less than 90%) when the molar ratio b(ii) / b(i) exceeds 25.

[0084] Comparative Example T shows that photocurable compositions using an MQ resin in the organopolysiloxane resin result in cured samples that are not optically clear and have low transmittance.

[0085] Comparative Examples U and V contain at least 50 mole % R 1 SiO 3 / 2 Units (R 1 This study shows that photocurable compositions using organopolysiloxane resins having (R) groups selected from alkyl and aryl groups and containing methacryloyloxypropyl-functional T units result in cured samples with no adhesive strength. Without being bound by theory, one possibility is that the (meth)acrylic-functional silicone resin increases the crosslink density, so the resin cures too hard and has too high a shear storage modulus to have sufficient tack for adequate adhesive strength. Therefore, the R of the organopolysiloxane resin 1 SiO 3 / 2 Unit R 1 It is important to use alkyl and aryl groups as groups, which by definition are non-functional in these crosslinking reactions.

[0086] Comparative Examples W and X contain less than 50 mole % R 1 SiO 3 / 2 Units (R 1are selected from alkyl and aryl groups) and having a Mw of less than 1000 g / mol, results in cured samples that do not have the desired adhesive strength.

[0087] Example 1, particularly in comparison with Comparative Example L, demonstrates that including the claimed organopolysiloxane resin component in the composition of Comparative Example A results in a composition that cures to an optically clear material, desirable adhesive strength, and shrinkage while having a desirable viscosity before cure. Comparing Examples 1 and 7 with Comparative Examples L and S demonstrates the importance of monofunctional acrylates containing ether and / or hydroxy groups to achieve optical clarity. Comparing Examples 1, 2, and 7-11 with Comparative Examples M-R demonstrates that compositions of the present invention can achieve greater than 90% transmittance at 550 nm while having a molar ratio of b(ii):b(i) ranging from 0:1 to 18:1. It is expected that optically clear materials can be produced with a molar ratio of b(ii):b(i) ranging from 0:1 to 22:1.

[0088] Examples 3, 4, 14, 24, 25, and 28-30 specifically demonstrate that the compositions of the present invention can be cured into optically clear materials with desirable adhesion, even in the absence of alkyl-containing, ether- and hydroxyl-free monofunctional (meth)acrylates.

[0089] Examples 3 and 4, and Examples 9 and 11 show that increasing the concentration of organopolysiloxane resin tends to increase the adhesive strength of the resulting curable composition.

[0090] In Examples 20 to 30, the photocurable silicone acrylate composition of the present invention is 1 SiO 3 / 2 The amount of units is at least 50 mole % of the siloxane units, and each R 1It has been shown that a variety of different organopolysiloxane resin components can be used to cure into optically transparent materials with desired properties, provided that R is selected from alkyl and aryl groups. The organopolysiloxane resin can contain M, D, and Q siloxane units, while R 1 SiO 3 / 2 Units (R 1 The amount of (wherein is selected from alkyl and aryl groups) must be at least 50 mole percent of the siloxane units.

[0091] The particular selection of organopolysiloxane resin also appears to reduce shrinkage of the curable composition upon cure.

[0092] Notably, none of the examples contain a plasticizer.

[0093] [Table 2]

[0094] [Table 3]

[0095] [Table 4]

[0096] [Table 5]

[0097] [Table 6]

Claims

1. A composition comprising the following components: (a) An organopolysiloxane resin containing at least 50 mole percent of T-siloxane units, in an amount of 10 to 90 mass percent, wherein the molar ratio of alkyl groups to aryl groups in the organopolysiloxane resin is in the range of 0:1 to 4:1, (b) (i) at least one monofunctional (meth)acrylate containing an ether group and / or a hydroxyl group; and optionally, (ii) At least one monofunctional (meth)acrylate containing an alkyl group and not containing an ether group or a hydroxyl group; A (meth)acrylate component consisting of 10 to 90 mass percent, The molar ratio of (ii) to (i) is in the range of 0:1 to 22:1, and if the (meth)acrylate component includes a monofunctional (meth)acrylate containing a hydroxyl group, it also includes, as part of component (i), at least one monofunctional (meth)acrylate containing an ether group, and / or component (ii) a monofunctional (meth)acrylate containing an alkyl group and not containing an ether group or a hydroxyl group, and (c) 0.1 to 11 mass percent of a crosslinking agent having at least two ethylenically unsaturated double bonds on average per molecule, (d) comprising 0.1 to 10 mass percent of a photoradical initiator, The mass percentage is relative to the total mass of components (a) to (c), and the total mass percentage of components (a) to (c) is 100 mass percent.

2. The composition according to claim 1, wherein the concentration of component (a) is 10 to 60 mass percent of the total mass of components (a) to (c), and the total concentration of components (b) and (c) is 40 to 90 mass percent.

3. Component a has the average chemical composition (I): M ａ D ｂ T ｃ Q ｄ (I) During the ceremony, The subscript 'a' represents the molar ratio of M siloxane units to moles of all siloxane units, and has an average value in the range of 0 to 0.

35. The subscript b represents the molar ratio of Dsiloxane units to moles of all siloxane units, and has an average value in the range of 0 to 0.

35. The subscript c represents the molar ratio of T siloxane units to moles of all siloxane units, and has an average value in the range of 0.50 to 1.

00. The subscript 'd' represents the molar ratio of Q siloxane units to moles of all siloxane units, and has an average value in the range of 0 to 0.

50. The sum of the subscripts a + b + c + d is equal to 1.

00. The molar ratio of alkyl groups to aryl groups is in the range of 0:1 to 4:

1. The concentration of OZ groups is in the range of 0 to 100 mole percent based on the moles of the organopolysiloxane resin, and The composition according to claim 1, wherein the ratio of subscripts a / c is in the range of 0 to 0.5, the ratio of subscripts b / c is in the range of 0 to 0.5, and the ratio of subscripts d / c is in the range of 0 to 0.

8.

4. The composition according to claim 1, wherein component (b)(i) is one compound selected from (meth)acrylate-functionalized ethylene glycol, (meth)acrylate-functionalized propylene glycol, (meth)acrylate-functionalized polyethers comprising a plurality of ethylene oxide and / or propylene oxide units, and hydroxyl-functionalized (meth)acrylate-functionalized compounds, or a combination of two or more compounds.

5. The composition according to claim 1, wherein component (c) is a compound comprising, on average, at least two ethylenically unsaturated double bonds, and at least one of the ethylenically unsaturated double bonds is part of a (meth)acryloyloxy group.

6. The composition according to claim 1, which does not contain a plasticizer.

7. A process comprising using a composition according to any one of claims 1 to 6 as an adhesive, the process comprising: applying the composition onto a first object; and then applying a second object to the composition so that it is in contact with the first object and the second object, sandwiching the composition between them.

8. The process according to claim 7, further comprising curing the composition between and in contact with the first object and the second object by exposing the composition to ultraviolet light.

9. The process according to claim 7, further comprising pre-curing the composition by exposing it to ultraviolet light after applying the composition to the first object and before applying the second object to the composition.

10. The process according to claim 7, wherein in the composition, the concentration of component (a) is 10 to 60 mass percent, and the total concentration of components (b) and (c) is 40 to 90 mass percent, and the composition is applied to the first object using an inkjet method.