Optical resin compositions and optical resin sheets

Abstract

An optical resin composition is provided that maintains good transparency when manufactured into optical resin sheets, while also exhibiting excellent adhesion, holding power, flexural strength, and durability. The optical resin composition comprises a polymer (A) and a crosslinking agent component (B), wherein the polymer (A) is one or more selected from the group consisting of acrylic polymers, urethane polymers, and rubber polymers, and the glass transition temperature (Tg) of the aforementioned polymer (A) is -110.0°C or higher and -10.0°C or lower; and the aforementioned crosslinking agent component (B) comprises an aliphatic or alicyclic polyisocyanate with a weight-average molecular weight of 2100 or higher and 200,000 or lower, and an average number of isocyanate groups of 3.5 or higher and 6.5 or lower.

Description

Technical Field

[0001] This invention relates to optical resin compositions and optical resin sheets. Background Technology

[0002] In recent years, for optical components such as adhesives, bonding agents, and films used in displays, the demands for higher image quality, touch panels, flexible displays, and diverse applications have led to requirements beyond just transparency and sufficient adhesive strength. These requirements extend to various properties including high weather resistance, high transparency, strong adhesion, high resistance to damp heat, bending resistance, reprocessability, contour following ability, and control over electrical characteristics. In particular, the increasing flexibility and foldability of displays have placed increasingly higher demands on the performance of adhesives and bonding agents used to bond optical components. Specifically, while maintaining transparency, these adhesives must also possess strong adhesion, high cohesiveness (high holding power), bending resistance, contour following ability, and high durability.

[0003] For example, Patent Document 1 discloses an optically transparent adhesive sheet that is flexible, can be thickened, uses a thermosetting polyurethane composition, and has excellent transparency.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 2017 / 145589 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] However, there is a need for materials that can maintain transparency better and offer superior adhesion, holding power, and flexural strength compared to the technologies described in Patent Document 1, etc. In particular, with the recent commercialization of foldable displays, flexural strength and durability have become increasingly important performance characteristics. Furthermore, Patent Document 1 uses a tackifier, but when using a tackifier, it tends to leach out significantly into the interface during long-term heating or humidification tests, or it easily becomes cloudy when mixed with moisture. Therefore, a softening method that does not use a tackifier is desired.

[0009] The present invention was made in view of the above circumstances, and provides an optical resin composition that not only maintains good transparency when made into an optical resin sheet, but also has excellent adhesion, holding power, flexural strength and durability; and an optical resin sheet obtained using the aforementioned optical resin composition.

[0010] Solution for solving the problem

[0011] That is, the present invention includes the following methods.

[0012] (1) An optical resin composition comprising a polymer (A) and a crosslinking agent (B), wherein the polymer (A) is one or more selected from the group consisting of acrylic polymers, urethane polymers, and rubber polymers.

[0013] The glass transition temperature (Tg) of the aforementioned polymer (A) is above -110.0℃ and below -10.0℃.

[0014] The aforementioned crosslinking agent component (B) comprises an aliphatic or alicyclic polyisocyanate with a weight-average molecular weight of 2,100 or more and 200,000 or less, and an average number of isocyanate groups of 3.5 or more and 6.5 or less.

[0015] (2) The optical resin composition according to (1), wherein the aforementioned aliphatic or alicyclic polyisocyanate is a polyisocyanate derived from at least one diisocyanate (b1) selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates and a polyol (b2) having a number average molecular weight of more than 550 and less than three functionalities.

[0016] The molar ratio of the isocyanate group of the aforementioned diisocyanate (b1) to the total molar ratio of the hydroxyl groups of the aforementioned polyol (b2), NCO / OH, is 1.5 or more and 30.0 or less.

[0017] (3) The optical resin composition according to (1) or (2), wherein the aforementioned aliphatic or alicyclic polyisocyanate has one or more functional groups selected from the group consisting of urethane groups and urea groups.

[0018] (4) An optical resin composition comprising a polymer (A) and a crosslinking agent (B), wherein the polymer (A) is one or more selected from the group consisting of acrylic polymers, urethane polymers, and rubber polymers.

[0019] The glass transition temperature (Tg) of the aforementioned polymer (A) is above -110.0℃ and below -10.0℃.

[0020] The aforementioned crosslinking agent component (B) comprises a polyisocyanate derived from at least one diisocyanate (b1) selected from aliphatic diisocyanates and alicyclic diisocyanates, and a polyol (b2) having a number average molecular weight of 1100 or more and an average number of hydroxyl groups of 1.5 or more and 2.5 or less.

[0021] The molar ratio of the isocyanate group of the aforementioned diisocyanate (b1) to the total molar ratio of the hydroxyl groups of the aforementioned polyol (b2), NCO / OH, is 1.5 or more and 30.0 or less.

[0022] The aforementioned polyisocyanates have a weight-average molecular weight of 2100 or more and 200,000 or less.

[0023] (5) The optical resin composition according to (4), wherein the average number of isocyanate groups in the aforementioned polyisocyanate is 1.5 or more and 5.2 or less.

[0024] (6) The optical resin composition according to (4) or (5), wherein the aforementioned polyisocyanate has one or more functional groups selected from the group consisting of urethane groups and urea groups.

[0025] The molar ratio of isocyanurate groups relative to the total molar amount of urea carbamate groups, urea diketone groups, iminooxadiazine diketone groups, isocyanurate groups, urea groups, carbamate groups, and biuret groups is less than 50 mol%.

[0026] (7) The optical resin composition according to (4) to (6), wherein the aforementioned polyisocyanate comprises a structural unit derived from a monool, diol or polyoxyalkylene alkyl ether having 2 or more carbon atoms and 18 or less.

[0027] (8) The optical resin composition according to (4) or (7), wherein the aforementioned crosslinking agent component (B) is coated on a release film, stored at 23°C and 65% humidity for 168 hours, and then heated at 50°C for 24 hours, and the resulting 50 μm thick cured film is peeled off from the release film, cut into pieces 10 mm wide and 40 mm long, and placed in a tensile testing machine with a clamping distance of 20 mm, and the tensile strength in a tensile test performed at 20 mm / min at 23°C is 2 MPa or more and 100 MPa or less.

[0028] (9) The optical resin composition according to (4) to (8), wherein the aforementioned crosslinking agent component (B) is coated on the release film, stored at 23°C and 65% humidity for 168 hours, and then heated at 50°C for 24 hours, and the cured film with a thickness of 50 μm formed therefrom is peeled off from the release film, and the haze value measured by the haze meter is 3.0% or less.

[0029] (10) The optical resin composition according to (1) to (9), wherein the content of the crosslinking agent component (B) is 0.01 parts by mass or more and 80.0 parts by mass or less relative to 100 parts by mass of the aforementioned polymer (A).

[0030] (11) The optical resin composition according to (1) to (10), wherein the weight-average molecular weight of the aforementioned polymer (A) is 1.0 × 10⁻⁶. 3 Above and 5.0×10 6 the following.

[0031] (12) The optical resin composition according to (1) to (11), wherein the aforementioned polymer (A) comprises structural units derived from monomers containing crosslinking functional groups.

[0032] The aforementioned crosslinking functional group is selected from one or more of the group consisting of hydroxyl, epoxy, carboxyl, amino and vinyl groups.

[0033] (13) The optical resin composition according to (12), wherein the content of the aforementioned structural units derived from monomers containing crosslinking functional groups is 0.01% by mass or more and 30% by mass or less relative to the total mass of the aforementioned polymer (A).

[0034] (14) The optical resin composition according to (1) to (13), wherein the aforementioned acrylic polymer comprises a structural unit of a (meth)acrylate monomer derived from the ester end with a carbon atom number of 1 or more and 18 or less.

[0035] (15) The optical resin composition according to (1) to (14), wherein the aforementioned urethane polymer has an urethane group and a structure derived from one or more of polyesters, polyethers and polycarbonates.

[0036] (16) The optical resin composition according to (1) to (15), wherein the aforementioned rubber polymer has one or more structures derived from the group consisting of styrene-butadiene rubber, polyisobutylene rubber, butyl rubber and styrene-isoprene-styrene block copolymer.

[0037] (17) The optical resin composition according to (2) to (16), wherein, relative to 100 parts by weight of the aforementioned diisocyanate (b1),

[0038] The content of the aforementioned polyol (b2) is 0.1 parts by mass or more and 900 parts by mass or less.

[0039] (18) The optical resin composition according to (2) to (17), wherein the aforementioned polyol (b2) is one or more polyols selected from the group consisting of polyester polyols, polyether polyols, epoxy polyols, polyolefin polyols and polycarbonate polyols.

[0040] (19) The optical resin composition according to (18), wherein the aforementioned polyol (b2) is one or more polyols selected from the group consisting of polyolefin polyols, polyether polyols and polyester polyols.

[0041] (20) The optical resin composition according to (19), wherein the aforementioned polyol (b2) is a polyester polyol.

[0042] (21) The optical resin composition according to (20), wherein the aforementioned polyester polyol is polycaprolactone polyol.

[0043] (22) The optical resin composition according to (1) to (21), wherein the isocyanate group content of the aforementioned crosslinking agent component (B) is 1.0% by mass or more and 9.5% by mass or less.

[0044] (23) The optical resin composition according to (1) to (22) further comprises, relative to 100 parts by weight of the aforementioned polymer (A), 0.01 parts by weight and 0.50 parts by weight of silane coupling agent (C).

[0045] (24) The optical resin composition according to (1) to (23), wherein the aforementioned crosslinking agent component (B) further comprises one or more selected from the group consisting of isocyanate compounds other than the aforementioned aliphatic or alicyclic polyisocyanates, carbodiimide compounds, oxazoline compounds, polyfunctional acrylate monomers, peroxides, titanium coupling agents, zirconium compounds, aluminum chelates, hydrazide compounds, epoxy crosslinking agents, thermal acid-producing agents, and photoacid-producing agents.

[0046] (25) The optical resin composition according to (1) to (24) wherein the aforementioned crosslinking agent component (B) is coated on a release film, stored at 23°C and 65% humidity for 168 hours, and then heated at 50°C for 24 hours, and the cured film with a thickness of 50 μm formed therefrom is peeled off from the release film, cut into pieces with a width of 10 mm and a length of 40 mm, and placed in a tensile testing machine with a distance of 20 mm between the clamps, and the tensile elongation in a tensile test performed at 20 mm / min at 23°C is 100% or more.

[0047] (26) An optical resin sheet, which is formed by curing the optical resin composition described in (1) to (24) by heat or light.

[0048] (27) The optical resin sheet according to (26), wherein the thickness of the aforementioned optical resin sheet is 1 μm or more and 1000 μm or less.

[0049] (28) According to (26) or (27), an optical resin sheet having a polyethylene terephthalate film on one side with a thickness of 50 μm, a width of 20 mm and a length of 100 mm is pressed onto an SUS304BA plate as the substrate by pressing it with a 2 kg roller once back and forth. After curing at 23°C for 30 minutes, the 180-degree peel adhesion force measured at 23°C and 300 mm / min is 1.0 N / 20 mm or more and 100.0 N / 20 mm or less. The optical resin sheet is obtained as follows: the aforementioned optical resin composition is coated on a polyethylene terephthalate film with a thickness of 25 μm, dried at 125°C for 3 minutes to cure it, and then stored at 23°C and 50% RH for 7 days.

[0050] (29) According to the optical resin sheet described in (28), an optical resin sheet having a polyethylene terephthalate film on one side with a thickness of 50 μm, a width of 20 mm and a length of 100 mm is pressed onto an SUS304BA plate as the substrate by using a 2 kg roller to press back and forth once. After curing at 23°C for 30 minutes, the 180-degree peel adhesion force measured at 23°C and a speed of 300 mm / min is 2.0 N / 20 mm or more and 100.0 N / 20 mm or less. The optical resin sheet is obtained as follows: the aforementioned optical resin composition is coated on a polyethylene terephthalate film with a thickness of 25 μm, dried at 125°C for 3 minutes to cure it, and then stored at 23°C and 50% RH for 7 days.

[0051] (30) According to the optical resin sheet described in (26) to (29), an optical resin sheet having a polyethylene terephthalate film on one side with a thickness of 50 μm, a width of 25 mm and a length of 130 mm is pressed onto a SUS304BA plate as the substrate by means of overlapping the width and length of 25 mm in a range of 25 mm. After curing at 23°C for 1 hour and further curing at 40°C for 30 minutes, a 500 g weight is suspended at the lower end of the optical resin sheet at 40°C for 1 hour. After returning to the 23°C environment, the offset of the optical resin sheet is less than 2.00 mm. The optical resin sheet is obtained as follows: the optical resin composition is coated on a polyethylene terephthalate film with a thickness of 25 μm, dried at 125°C for 3 minutes to cure it, and then stored at 23°C and 50% RH for 7 days.

[0052] (31) The optical resin sheet according to (26) to (30) wherein the aforementioned optical resin composition is coated on a peel-treated polyethylene terephthalate film with a thickness of 38 μm, dried at 125°C for 3 minutes to cure it, stored at 23°C and 50% RH for 7 days, peeled off from the aforementioned peel-treated polyethylene terephthalate film, and the resulting optical resin sheet with a thickness of 50 μm is pasted onto glass with a haze value of 0.1%, and the haze value measured by a haze meter is 2.0% or less.

[0053] (32) The optical resin sheet according to (26) to (31) wherein the aforementioned optical resin composition is coated on a peel-treated polyethylene terephthalate film with a thickness of 38 μm, dried at 125°C for 3 minutes to cure it, stored at 23°C and 50% RH for 7 days, peeled off from the aforementioned peel-treated polyethylene terephthalate film, and the resulting optical resin sheet with a thickness of 50 μm is stored at 23°C and 50% RH for 7 days, wrapped with a mesh sheet, immersed in ethyl acetate at 23°C for 1 week, and then dried at 120°C for 2 hours, wherein the gel fraction calculated therefrom is 45.0% by mass or more and 99.9% by mass or less.

[0054] (33) The optical resin sheet according to (26) to (32), wherein the aforementioned optical resin composition is coated on a peel-treated polyethylene terephthalate film with a thickness of 38 μm, dried at 125°C for 3 minutes to cure it, and then stored at 23°C and 50% RH for 7 days. The film is then peeled off from the aforementioned peel-treated polyethylene terephthalate film, and the resulting 50 μm thick optical resin sheet is stacked with a thickness of 200 μm. It is then cut into pieces with a width of 10 mm and a length of 40 mm, and placed in a tensile testing machine with a clamp spacing of 10 mm. The elastic modulus in a tensile test performed at 23°C and a speed of 300 mm / min is 0.40 N / mm². 2 The following applies, and the elongation in the aforementioned tensile test is 100% or more.

[0055] (34) According to (33), the aforementioned optical resin composition is coated onto a 38 μm thick peel-treated polyethylene terephthalate film, dried at 125°C for 3 minutes to cure it, and then stored at 23°C and 50% RH for 7 days. The resulting 50 μm thick optical resin sheet is then peeled off from the peel-treated polyethylene terephthalate film, and the resulting 50 μm thick optical resin sheet is stacked with a thickness of 200 μm. It is then cut into pieces 10 mm wide and 40 mm long, and placed in a tensile testing machine with a clamping distance of 10 mm. The elastic modulus in a tensile test performed at 23°C and a speed of 300 mm / min is 0.40 N / mm². 2 The following applies, and the elongation in the aforementioned tensile test is 200% or more.

[0056] (35) The optical resin sheet according to (26) to (34), wherein the aforementioned optical resin sheet is an optical transparent adhesive sheet or an optical transparent bonding sheet.

[0057] The effects of the invention

[0058] The optical resin composition according to the above method provides an optical resin composition that not only maintains good transparency when manufactured into an optical resin sheet, but also exhibits excellent adhesion, holding power, flexural strength, and durability. The optical resin sheet according to the above method is formed by curing the aforementioned optical resin composition, and it has good transparency, as well as excellent adhesion, holding power, flexural strength, and durability. Detailed Implementation

[0059] Hereinafter, a detailed description will be given of a method for carrying out the present invention (hereinafter referred to as "this embodiment"). This embodiment is merely an example for illustrating the present invention and does not imply that the present invention is limited to the following content. The present invention can be implemented with appropriate modifications within its scope.

[0060] It should be noted that in this specification, "polyol" refers to a compound having two or more hydroxyl groups (-OH) in one molecule.

[0061] In addition, in this specification, "polyisocyanate" refers to a reactant obtained by bonding multiple monomeric compounds having two or more isocyanate groups (-NCO).

[0062] In addition, unless otherwise specified in this specification, "(meth)acrylic acid" includes methacrylic acid and acrylic acid, and "(meth)acrylate" includes methacrylate and acrylate.

[0063] Optical Resin Composition 1

[0064] The optical resin composition of this embodiment includes a polymer (A) and a crosslinking agent component (B).

[0065] Polymer (A) is one or more polymers selected from the group consisting of acrylic polymers, urethane polymers and rubber polymers.

[0066] The glass transition temperature (Tg) of polymer (A) is -110.0°C or higher and -10.0°C or lower, preferably -90.0°C or higher and -20.0°C or lower, more preferably -80.0°C or higher and -30.0°C or lower, and even more preferably -75.0°C or higher and -35.0°C or lower. By keeping the glass transition temperature (Tg) of polymer (A) within the above range, there is a tendency for it to have excellent adhesion and flexural strength when manufactured into optical resin sheets.

[0067] Regarding the glass transition temperature of polymer (A), for example, for a substance obtained by vacuum drying after removing organic solvent and water from a solution in which polymer (A) is dissolved or dispersed under reduced pressure, a differential scanning calorimeter (DSC) is used to measure the glass transition temperature at a heating rate of 5°C / min, and the value obtained is used as the glass transition temperature.

[0068] The aforementioned crosslinking agent component (B) comprises an aliphatic or alicyclic polyisocyanate with a weight-average molecular weight of 2,100 or more and 200,000 or less, and an average number of isocyanate groups of 3.5 or more and 6.5 or less.

[0069] The optical resin composition of this embodiment, by having the above-described structure, enables the production of an optical resin sheet that not only maintains good transparency but also exhibits excellent adhesion, holding power, flexural strength, and durability.

[0070] It should be noted that the flexural resistance mentioned here, as shown in the examples described later, is evaluated using the elastic modulus (Young's modulus), maximum stress, and elongation for the purpose of simplification. This is evident in the low elastic modulus (Young's modulus), high elongation, and high maximum stress of the layer formed by curing the optical resin composition. In other words, materials that readily follow deformation caused by bending, easily relax stress, and are difficult to break (high maximum stress) exhibit excellent flexural resistance. The preferred range for the elastic modulus is described later.

[0071] <Polymer (A)>

[0072] Polymer (A) is one or more polymers selected from the group consisting of acrylic polymers, urethane polymers, and rubber polymers. Preferably, it is a urethane polymer or an acrylic polymer, and more preferably an acrylic polymer.

[0073] The polymer (A) preferably comprises structural units derived from monomers containing crosslinking functional groups (hereinafter sometimes referred to as "monomer units containing crosslinking functional groups").

[0074] The monomer containing the crosslinking functional group has both a polymerizable functional group and a crosslinking functional group capable of forming a crosslinking structure with the crosslinking agent component (B). Examples of polymerizable functional groups include vinyl groups. Examples of crosslinking functional groups include hydroxyl, thiol, amino, amide, epoxy, carboxyl, and vinyl groups, among which hydroxyl, epoxy, carboxyl, amino, or vinyl groups are preferred, hydroxyl is more preferred, and a combination of carboxyl and hydroxyl groups or hydroxyl groups themselves are particularly preferred.

[0075] The content of structural units derived from monomers containing crosslinking functional groups relative to the total mass of polymer (A) is preferably 0.01% by mass or more and 30% by mass or less, more preferably 0.02% by mass or more and 25% by mass or less, and even more preferably 0.03% by mass or more and 20% by mass or less. By keeping the content of structural units derived from monomers containing crosslinking functional groups within the above-mentioned range, there is a tendency for the adhesive strength, cohesive strength (holding strength), durability, and curability to be better when manufacturing optical resin sheets.

[0076] The content of structural units derived from monomers containing crosslinking functional groups can be calculated based on, for example, the amount of monomers (a1) containing crosslinking functional groups used in the manufacture of polymer (A). Alternatively, it can be calculated based on, for example, the amount of structural units derived from monomers containing crosslinking functional groups used in the manufacture of polymer (A). 1 H-NMR spectrum, 12 The composition ratio is calculated by combining C-NMR, IR, and mass spectrometry analyses.

[0077] The weight-average molecular weight Mw(A) of polymer (A) is preferably 1.0 × 10⁻⁶. 3 Above and 5.0×10 6 The following, and more preferably, is 2.0 × 10 3 Above and 3.0×10 6 The following, and more preferably, is 2.5 × 10 3 Above and 2.5×10 6 The following, and more preferably, is 5.0 × 10 3 Above and 2.5×10 6 The following, and more preferably 1.0×10 4 Above and 2.5×10 6 The following, and more preferably 1.0 × 10 4 Above and 2.4×10 6 The following is a further preferred lower limit for the weight-average molecular weight Mw(A) of polymer (A). 4 The preferred value is 1.0×10.5 The optimal value is 3.0 × 10⁻⁶. 5 .

[0078] By ensuring that the weight-average molecular weight Mw(A) of polymer (A) is within the aforementioned range, there is a tendency for it to exhibit superior adhesive strength, cohesive strength (holding power), moisture and heat resistance, and flexural strength when manufactured into optical resin sheets. The weight-average molecular weight Mw(A) of polymer (A) can be determined using, for example, the method described in the examples described later.

[0079] [Acrylic polymers]

[0080] Acrylic polymers are polymers synthesized by copolymerizing a monomer (a1) containing a crosslinking functional group with a (meth)acrylate monomer (a2) having 1 or more and 18 or fewer carbon atoms at the end of the ester group. That is, acrylic polymers comprise monomer units containing crosslinking functional groups and structural units derived from the aforementioned (meth)acrylate monomers (hereinafter sometimes referred to as "(meth)acrylate monomer units").

[0081] The crosslinking functional groups of monomers (a1) containing crosslinking functional groups in acrylic polymers can also be acquired by modification after polymerizing acrylates.

[0082] Acrylic polymers may contain only one structural unit derived from a monomer (a1) containing a crosslinking functional group and one structural unit derived from a (meth)acrylate monomer (a2), or they may contain a combination of two or more structural units. That is, an acrylic polymer may be a polymer copolymerized by copolymerizing one monomer (a1) containing a crosslinking functional group and one (meth)acrylate monomer (a2), or it may be a polymer copolymerized by copolymerizing two or more monomers (a1) containing a crosslinking functional group and one (meth)acrylate monomer (a2). It should be noted that the (meth)acrylate monomer (a2) may or may not have a crosslinking functional group, preferably not.

[0083] Acrylic polymers can include structural units derived from monomers (a1) containing crosslinking functional groups and structural units derived from (meth)acrylate monomers (a2), as well as structural units derived from other polymeric monomers (a3) ​​(hereinafter sometimes simply referred to as "other polymeric monomers (a3)"). That is, acrylic polymers can be polymers synthesized by copolymerizing one or more monomers (a1) containing crosslinking functional groups, one or more (meth)acrylate monomers (a2), and one or more other polymeric monomers (a3). It should be noted that the other polymeric monomers (a3) ​​may or may not have crosslinking functional groups.

[0084] As a monomer (a1) containing crosslinking functional groups, a polymerizable (meth)acrylic monomer having crosslinking functional groups is preferred.

[0085] Examples of polymerizable (meth)acrylic monomers having crosslinking functional groups include, for example, the monomers shown in (i) to (viii) below. They can be used alone or in combination of two or more.

[0086] (i) Acrylates containing hydroxyl groups, such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 4-hydroxybutyl acrylate, 6-hydroxyhexyl acrylate, and 8-hydroxyoctyl acrylate.

[0087] (ii) 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 4-hydroxybutyl methacrylate, 6-hydroxyhexyl methacrylate, 8-hydroxyoctyl methacrylate and other methacrylates containing hydroxyl groups.

[0088] (iii) (meth) acrylates containing polyhydroxyl groups, such as glycerol monoacrylate or methacrylate monoacrylate, trimethylolpropane monoacrylate or methacrylate monoacrylate.

[0089] (iv) Unsaturated carboxylic acids such as acrylic acid and methacrylic acid.

[0090] (v) (meth)acrylamide and other unsaturated amides.

[0091] (vi) Dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and other (meth)acrylates containing amino groups.

[0092] (vii) Glycidyl methacrylate and other (meth)acrylates with epoxy groups.

[0093] (viii) 2-Carboxyethyl acrylate, 2-Carboxyethyl methacrylate, and other (meth)acrylates containing a carboxyl group.

[0094] When the polymerizable (meth)acrylic monomer having crosslinking functional groups is a (meth)acrylate monomer having crosslinking functional groups, the number of carbon atoms in the ester portion is preferably 1 or more and 18 or less, more preferably 1 or more and 12 or less, further preferably 1 or more and 10 or less, particularly preferably 1 or more and 8 or less, and most preferably 2 or more and 8 or less.

[0095] The number of carbon atoms at the end of the ester group in the (meth)acrylate monomer (a2) is preferably 1 or more and 18 or less.

[0096] Examples of (meth)acrylate monomers (a2) include, for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, pentyl methacrylate, isoamyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, heptyl methacrylate, octyl methacrylate, isooctyl methacrylate, nonyl methacrylate, and isononyl methacrylate. (Meth)acrylates include decyl methacrylate, isodecyl methacrylate, undecyl methacrylate, dodecyl methacrylate (laurate methacrylate), tridecyl methacrylate, tetradecyl methacrylate, pentadecyl methacrylate, hexadecyl methacrylate, heptadecanyl methacrylate, stearyl methacrylate, isostearyl methacrylate, nonadecanyl methacrylate, eicosyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, and other methacrylates. They can be used alone or in combination of two or more.

[0097] Other polymerizable monomers (a3) ​​include, for example, the monomers shown in (i) to (iv) below. One of them may be used, or two or more may be used in combination.

[0098] (i) Unsaturated carboxylic acids such as maleic acid and itaconic acid.

[0099] (ii) Monomers with epoxy groups, such as 1,2-epoxy-4-vinylcyclohexane, allyl glycidyl ether, and 4-hydroxybutyl acrylate glycidyl ether.

[0100] (iii) Unsaturated amides such as N-hydroxymethylacrylamide, diacetone acrylamide, and dimethylaminopropylacrylamide.

[0101] (iv) Vinyl acetate, (meth)acrylonitrile, styrene, vinyltoluene, N-vinylpyrrolidone, N-vinylcaprolactam, acryloylmorpholine.

[0102] Furthermore, as other monomers capable of copolymerizing with monomers (a1) and (meth)acrylate monomers (a2) containing crosslinking functional groups, polymerizable UV-stable monomers disclosed in Japanese Patent Application Publication No. 1-261409 (Reference 1) and Japanese Patent Application Publication No. 3-006273 (Reference 2) can be used.

[0103] Specifically, examples of polymerizable UV-stabilized monomers include 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 1-crotonyl-4-crotonyloxy-2,2,6,6-tetramethylpiperidine, and 2-hydroxy-4-(3-methacryloyloxy-2-hydroxypropoxy)benzophenone.

[0104] For example, by solution polymerization of the above-mentioned monomer components in the presence of known free radical polymerization initiators such as peroxides and azo compounds, and dilution with organic solvents as needed, acrylic polymers can be obtained.

[0105] When an acrylic polymer with an aqueous matrix is ​​obtained, it can be manufactured by known methods such as solution polymerization of an olefinic unsaturated compound and conversion to an aqueous layer, or emulsion polymerization. In this case, water solubility or water dispersibility can be imparted by neutralizing the acidic portions of acrylic acid, methacrylic acid, or sulfonic acid monomers with amines or ammonia.

[0106] The content of structural units derived from monomers (a1) containing crosslinking functional groups relative to the total mass of the acrylic polymer is preferably 0.01% by mass or more and 30% by mass or less, more preferably 0.02% by mass or more and 25% by mass or less, and even more preferably 0.03% by mass or more and 20% by mass or less. By keeping the content of structural units derived from monomers (a1) containing crosslinking functional groups within the above-mentioned range, there is a tendency for the adhesive strength, cohesive strength (holding strength), and durability to be better when manufacturing optical resin sheets.

[0107] The content of structural units derived from (meth)acrylate monomer (a2) relative to the total mass of the acrylic polymer is preferably 0.01% by mass or more and 99.99% by mass or less, more preferably 10% by mass or more and 99.99% by mass or less, further preferably 50% by mass or more and 99.99% by mass or less, more preferably 60% by mass or more and 99.99% by mass or less, and particularly preferably 80% by mass or more and 99.99% by mass or less. By keeping the content of structural units derived from (meth)acrylate monomer (a2) within the above-mentioned range, there is a tendency for the adhesive strength, cohesive strength (holding strength), and flexural strength to be superior when producing optical resin sheets.

[0108] The content of structural units derived from the monomer (a1) containing crosslinking functional groups and the content of structural units derived from the (meth)acrylate monomer (a1) can be calculated based on, for example, the respective blending amounts of the monomer (a1) containing crosslinking functional groups and the (meth)acrylate monomer (a2) used in the manufacture of acrylic polymers. Alternatively, it can be calculated based on, for example, by...1 H-NMR spectrum, 12 The composition ratio is calculated by combining C-NMR, IR, and mass spectrometry analyses.

[0109] [Carbamate polymers]

[0110] Carbamate polymers are polymers containing carbamate groups. They are polymers produced by repeated addition reactions of aromatic, aliphatic, or alicyclic diisocyanates with compounds containing active hydrogen. Examples of such polymers include those with carbamate bonds in the polymer and hydroxyl groups at the polymer side chains and ends.

[0111] Among them, as a urethane polymer, it is preferred to have a urethane group and a structure derived from one or more of the groups selected from polyester, polyether and polycarbonate.

[0112] [Rubber-based polymers]

[0113] Examples of rubber-based polymers include styrene-butadiene rubber, polyisobutylene rubber, butyl rubber, and styrene-isoprene-styrene block copolymers. Alternatively, a rubber-based adhesive composition comprising 10 to 100 parts by weight of isoprene rubber, 0.1 to 90 parts by weight of other rubber components, and 20 to 150 parts by weight of tackifying resin, softener, and other components as described in Japanese Patent Application Publication No. 6-172726 (Reference 3) is preferred.

[0114] Among them, as a rubber-based polymer, it is preferred to have one or more structures derived from the group consisting of styrene-butadiene rubber, polyisobutylene rubber, butyl rubber and styrene-isoprene-styrene block copolymer.

[0115] <Crosslinking agent component (B)>

[0116] The crosslinking agent component (B) contains an aliphatic or alicyclic polyisocyanate (b) with a weight average molecular weight of 2,100 or more and 200,000 or less, and an average number of isocyanate groups of 3.5 or more and 6.5 or less.

[0117] The content of aliphatic or alicyclic polyisocyanate (b) in the crosslinking agent component (B) relative to the total mass of the crosslinking agent component (B) is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, particularly preferably 90% by mass or more, and most preferably 100% by mass. By ensuring that the content of aliphatic or alicyclic polyisocyanate (b) in the crosslinking agent component (B) is at or above the aforementioned lower limit, the effects of the optical resin composition of this embodiment can be more fully realized.

[0118] The weight-average molecular weight Mw(b) of the aliphatic or alicyclic polyisocyanate (b) is 2100 or more and 200,000 or less, preferably 2500 or more and 200,000 or less, more preferably 3000 or more and 190,000 or less, even more preferably 3500 or more and 180,000 or less, and particularly preferably 4000 or more and 170,000 or less. By ensuring that the weight-average molecular weight Mw(b) of the aliphatic or alicyclic polyisocyanate (b) is within the above-mentioned range, the elastic modulus (Young's modulus) can be further reduced, the elongation can be further increased, and the breaking strength can be further improved for the resulting optical resin sheet.

[0119] Mw(b) of aliphatic or alicyclic polyisocyanates (b) is the weight-average molecular weight based on polystyrene as determined by GPC.

[0120] The average number of isocyanate groups in the aliphatic or alicyclic polyisocyanate (b) is 3.5 or more and 6.5 or less, preferably 3.7 or more and 6.3 or less, more preferably 4.0 or more and 6.3 or less, and even more preferably 4.0 or more and 6.1 or less. By ensuring that the average number of isocyanate groups in the aliphatic or alicyclic polyisocyanate (b) is within the above-mentioned range, the polymer (A) and the crosslinking agent component (B) can more effectively form a crosslinking network. For the resulting optical resin sheet, even when the gel fraction is increased due to crosslinking, the elongation and tensile strength can be further increased.

[0121] The average number of isocyanate groups (fn) of aliphatic or alicyclic polyisocyanates (b) can be calculated using the following formula. In the formula, "Mn" represents the number-average molecular weight of the aliphatic or alicyclic polyisocyanate (b), and "NCO%" represents the isocyanate group content of the aliphatic or alicyclic polyisocyanate (b). The number-average molecular weight Mn of the aliphatic or alicyclic polyisocyanate (b) is the weight-average molecular weight based on polystyrene as determined by GPC. The method for determining NCO% is described below.

[0122] [fn] = [Mn] × [NCO%] / 4200

[0123] The aliphatic or alicyclic polyisocyanate (b) is preferably a polyisocyanate derived from at least one diisocyanate (b1) selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates and a polyol (b2) with a number average molecular weight of more than 550 and less than three functions.

[0124] The molar ratio of the isocyanate groups of the aforementioned diisocyanate (b1) to the total molar ratio of the hydroxyl groups of the aforementioned polyol (b2), NCO / OH, is preferably 1.5 or more and 30.0 or less, more preferably 2.0 or more and 25.0 or less, and even more preferably 2.5 or more and 22.0 or less. By keeping the NCO / OH ratio within the above-mentioned range, it is possible to synthesize the crosslinking agent component (B) without gelation, and for the resulting optical resin sheet, the elastic modulus can be further reduced, the elongation can be further increased, and the tensile strength can be further improved.

[0125] As an aliphatic or alicyclic polyisocyanate (b), it can be a polyisocyanate having structural units derived from both diisocyanate and polyol (b2) in one molecule, or it can be a mixture of polyisocyanates having at least one structural unit derived from the group consisting of diisocyanate and polyol (b2) in one molecule.

[0126] Aliphatic or alicyclic polyisocyanates (b) may have one or more functional groups selected from the group consisting of urethane, urea diketone, iminooxadiazine diketone, isocyanurate, urea, urethane, and biuret. Preferably, they have one or more functional groups selected from the group consisting of urethane, urea diketone, biuret, urea, and isocyanurate, and more preferably, they have one or more functional groups selected from the group consisting of urethane and urea diketone. On the other hand, if a large amount of isocyanurate groups are included, there is a tendency for the structure to become too rigid; therefore, relative to the total molar percentage of the above structure, the isocyanurate group is preferably 60 mol% or less, more preferably 50 mol% or less.

[0127] [Diisocyanate (b1)]

[0128] Diisocyanate (b1) is selected from at least one of the groups consisting of aliphatic diisocyanates and alicyclic diisocyanates.

[0129] As aliphatic diisocyanates, not limited to the following substances, examples include 1,4-diisocyanate butane, 1,5-diisocyanate pentane, ethyl (2,6-diisocyanate)hexanoate, 1,6-diisocyanate hexane (sometimes abbreviated as "HDI"), 1,9-diisocyanate nonane, 1,12-diisocyanate dodecane, 2,2,4- or 2,4,4-trimethyl-1,6-diisocyanate hexane, etc. These aliphatic diisocyanates can be used alone or in combination of two or more.

[0130] As alicyclic diisocyanates, not limited to the following substances, examples include 1,3- or 1,4-bis(isocyanate methyl)cyclohexane (hereinafter sometimes abbreviated as "hydrogenated XDI"), 1,3- or 1,4-diisocyanate cyclohexane, 3,5,5-trimethyl-1-isocyanate methyl-3-(isocyanate methyl)cyclohexane (hereinafter sometimes abbreviated as "IPDI"), 4-4'-diisocyanate methyl-dicyclohexylmethane (hereinafter sometimes abbreviated as "hydrogenated MDI"), 2,5- or 2,6-diisocyanate methyl norbornene, etc. These alicyclic diisocyanates can be used alone or in combination of two or more.

[0131] These aliphatic and alicyclic diisocyanates can be used alone or in combination of two or more.

[0132] Furthermore, from the viewpoint of softness, the mass ratio of alicyclic diisocyanate to aliphatic diisocyanate is preferably 0 / 100 or more and 30 / 70 or less, more preferably 0 / 100 or more and 20 / 80 or less.

[0133] The preferred diisocyanate is HDI, IPDI, hydrogenated XDI, or hydrogenated MDI, more preferably HDI or IPDI, and even more preferably HDI.

[0134] In the manufacture of polyisocyanate (b), an isocyanate monomer as shown below can be further used in addition to the diisocyanate described above.

[0135] (1) Aromatic diisocyanates such as diphenylmethane-4,4'-diisocyanate (MDI), 1,5-naphthalene diisocyanate, toluene diisocyanate (TDI), phenylmethylene diisocyanate, and m-tetramethylphenylmethylene diisocyanate (TMXDI).

[0136] (2) Triisocyanates such as 4-isocyanate methyl-1,8-octamethylene diisocyanate (hereinafter sometimes referred to as "NTI"), 1,3,6-hexamethylene triisocyanate (hereinafter sometimes referred to as "HTI"), bis(2-isocyanate ethyl) 2-isocyanate glutarate (hereinafter sometimes referred to as "GTI"), and lysine triisocyanate (hereinafter sometimes referred to as "LTI").

[0137] [Polyol (b2)]

[0138] Polyols (b2) are polyols with a number average molecular weight of more than 550 and with more than three functions and less than five functions.

[0139] The number average molecular weight of the polyol (b2) is greater than 550, preferably 800 or more. By making the number average molecular weight of the polyol (b2) above the above lower limit, the cured film formed by curing only the polyisocyanate (b) has high tensile strength, high elongation, and good flexibility.

[0140] On the other hand, there is no particular limitation on the upper limit of the number average molecular weight of the polyol (b2). For example, it can be set to 12,000, preferably 11,000, more preferably 10,000, even more preferably 9,000, even more preferably 8,000, even more preferably 6,000, and particularly preferably 5,000.

[0141] The number-average molecular weight Mn of the polyol (b2) is, for example, the number-average molecular weight of polystyrene based on GPC. Furthermore, when two or more polyols (b2) are mixed, the number-average molecular weight of the mixture is calculated.

[0142] As a polyol (b2), any polyol with more than three functions and less than five functions is acceptable, preferably a polyol with more than three functions and less than four functions, and more preferably a polyol with three functions (triol).

[0143] The trifunctional polyol (triol) is preferably selected from at least one trifunctional polyol (triol) chosen from the group consisting of polyester polyol, polyether polyol, epoxy polyol, polyolefin polyol and polycarbonate polyol, and more preferably a trifunctional polyester polyol.

[0144] As trifunctional polyester polyols, examples include any of the following polyester polyols, such as (1) or (2).

[0145] (1) A polyester polyol obtained by condensation reaction of one or more dicarboxylic acids with one or more triols.

[0146] (2) Polycaprolactone polyol obtained by ring-opening polymerization of ε-caprolactone using triol.

[0147] Examples of the aforementioned dicarboxylic acids include succinic acid, adipic acid, dimer acids, maleic anhydride, phthalic anhydride, isophthalic acid, terephthalic acid, and 1,4-cyclohexanedicarboxylic acid.

[0148] Examples of the aforementioned triols include trimethylolpropane, glycerol, pentaerythritol, 2-methylolpropanediol, and ethoxylated trimethylolpropane.

[0149] Among them, the preferred trifunctional polyester polyol is the trifunctional polycaprolactone polyol.

[0150] Commercially available trifunctional polycaprolactone polyols include, for example, "PLACCEL 308" (number average molecular weight 850), "PLACCEL 309" (number average molecular weight 900), "PLACCEL 312" (number average molecular weight 1250), and "PLACCEL 320" (number average molecular weight 2000).

[0151] In aliphatic or alicyclic polyisocyanates (b), the content (feed amount) of polyol (b2) relative to 100 parts by mass of diisocyanate (b1) is generally preferably 0.1 parts by mass or more and 900.0 parts by mass or less, more preferably 1.0 parts by mass or more and 850.0 parts by mass or less, and even more preferably 2.0 parts by mass or more and 800.0 parts by mass or less.

[0152] By keeping the content of polyol (b2) below the aforementioned upper limit, the polyisocyanate (b) can be maintained in a liquid state without gelation during manufacturing, resulting in better curability and flexibility when used to produce optical resin sheets. Conversely, by keeping the content of polyol (b2) above the aforementioned lower limit, the cured film formed by curing polyisocyanate (b) alone exhibits high elongation and improved flexibility. Furthermore, optical resin sheets with superior adhesion, cohesion, flexural strength, and durability can be obtained.

[0153] The content of polyol (b2) can be calculated based on, for example, the amount of diisocyanate and polyol (b2) mixed when manufacturing polyisocyanate (b).

[0154] [Other cross-linking agent components]

[0155] The crosslinking agent component (B) may, in addition to including the above-mentioned aliphatic or alicyclic polyisocyanate (b), also include one or more other crosslinking agent components (b') selected from the group consisting of isocyanate compounds, carbodiimide compounds, oxazoline compounds, polyfunctional acrylate monomers, peroxides, epoxy crosslinking agents, titanium coupling agents, zirconium compounds, aluminum chelates, acyl hydrazine compounds, thermal acid-producing agents, and photoacid-producing agents.

[0156] Examples of isocyanate compounds other than aliphatic or alicyclic polyisocyanates (b) include, for example, the aliphatic or alicyclic diisocyanate monomers illustrated in the diisocyanate (b1) above. Additionally, examples include aromatic diisocyanates and triisocyanates illustrated in the diisocyanate (b1) above, and polyisocyanates derived from them.

[0157] As carbodiimide compounds, they can be obtained, for example, by causing the isocyanate groups of a polyisocyanate compound to undergo a decarbonylation reaction. Commercially available carbodiimide compounds include, for example, CARBODILITE V-02, CARBODILITE V-02-L2, CARBODILITE V-04, CARBODILITE E-01, and CARBODILITE E-02 (all manufactured by Nisshinbo Co., Ltd., trade names).

[0158] Examples of oxazoline compounds include polymeric compounds having at least two oxazoline groups in their side chains, and monomeric compounds having at least two oxazoline groups in one molecule.

[0159] Examples of multifunctional acrylate monomers include tripentaerythritol acrylate, trimethylolpropane triacrylate, a condensation product of pentaerythritol and acrylic acid, and 1,6-hexanediol diacrylate. The multifunctional acrylate monomers mentioned here contain two or more vinyl groups, distinguishing them from the monomers mentioned above that contain crosslinking functional groups.

[0160] Examples of peroxides include benzoyl peroxide, cumene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyn-3, di-tert-butylperoxide, tert-butylcumyl peroxide, di(2-tert-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, dicumyl peroxide, di-tert-butylperoxyisophthalate, tert-butylperoxybenzoate, 2,2-bis(tert-butylperoxy)butane, 2,2-bis(tert-butylperoxy)octane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, di(trimethylsilyl)peroxide, trimethylsilyltriphenylsilylperoxide, etc.

[0161] Examples of titanium coupling agents include isopropyl triisostearoyl titanate, isopropyl tris(dioctyl pyrophosphate) titanate, isopropyl tris(N-aminoethyl-aminoethyl) titanate, tetraoctyl bis(di-tetrazyl phosphite) titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(di-tetrazyl) phosphite titanate, bis(octyl pyrophosphate)oxyacetate titanate, bis(dioctyl pyrophosphate) ethylene titanate, isopropyl trioctyl oxytane titanate, isopropyl dimethacryloyl isostearoyl titanate, isopropyl tris(dodecylbenzenesulfonyl) titanate, isopropyl isostearodiacryloyl titanate, isopropyl tris(dioctyl sulfate) titanate, isopropyl tricumylphenyl titanate, and tetraisopropyl bis(dioctyl phosphite) titanate.

[0162] Examples of zirconium compounds include zirconium tetraacetylacetone, zirconium oxy2-ethylhexanoate, and zirconium oxycycloalkanoate.

[0163] Examples of aluminum chelates include aluminum triacetylacetonate.

[0164] Examples of acylhydrazides include aliphatic carboxylic acid acylhydrazides, alicyclic carboxylic acid acylhydrazides, and aromatic carboxylic acid acylhydrazides.

[0165] Examples of aliphatic and alicyclic carboxylic acid acyl hydrazides include saturated or unsaturated fatty acid acyl hydrazides such as lauroyl hydrazide, palmityl hydrazide, stearyl hydrazide, adipic acid diacyl hydrazide, sebacate diacyl hydrazide, dodecanoic acid diacyl hydrazide, eicosanoic acid diacyl hydrazide, and sorbic acid hydrazide; hydroxy fatty acid acyl hydrazides such as α-hydroxybutyric acid hydrazide and glyceryl hydrazide; 7,11-octadecadiene-1,18-dicarbonyl hydrazide, 1,3-bis(hydrazylcarbonylethyl)-5-isopropylhydantoin, and tri(hydrazylcarbonylethyl) isocyanurate, etc.

[0166] Examples of aromatic carboxylic acid hydrazides include 1-naphthoic acid hydrazide, 2-naphthoic acid hydrazide, phthalic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, and 2,6-naphthoic acid dihydrazide.

[0167] Examples of epoxy crosslinking agents include multifunctional epoxy resins manufactured by Mitsubishi Gas Chemical Co., Ltd., under the trade names "TETRAD-C" and "TETRAD-X".

[0168] Examples of heat-generating acid agents include onium salts and other salts formed from strong acids and bases, such as imide sulfonates, which have the function of generating acids due to heat.

[0169] Examples of onium salts include diaryl iodonium salts such as aryl diazonium salts and diphenyliodonium salts; di(alkylaryl)iodonium salts such as di(tert-butylphenyl)iodonium salt; trialkyl sulfonium salts such as trimethyl sulfonium salt; dialkyl monoaryl sulfonium salts such as dimethylphenyl sulfonium salt; diaryl monoalkyl iodonium salts such as diphenylmethyl sulfonium salt; and triaryl sulfonium salts.

[0170] In addition to the onium salts mentioned above, other salts formed from strong acids and bases, such as pyridinium salts, can also be used as salts formed from strong acids and bases. Examples of strong acids include aryl sulfonic acids such as p-toluenesulfonic acid and benzenesulfonic acid; perfluoroalkyl sulfonic acids such as camphorsulfonic acid, trifluoromethanesulfonic acid, and nonafluorobutyric acid; and alkyl sulfonic acids such as methanesulfonic acid, ethanesulfonic acid, and butyric acid. Examples of bases include pyridine; alkylpyridines such as 2,4,6-trimethylpyridine; N-alkylpyridines such as 2-chloro-N-methylpyridine; and halo-N-alkylpyridines.

[0171] Examples of imide sulfonates include naphthyl imide sulfonate and phthalimide sulfonate; there are no limitations on any compound that produces an acid due to heat.

[0172] As photoacid generators, photoacid generators that produce acids capable of cationic polymerization through ultraviolet irradiation can be used, and the reaction can be further promoted by heating. Examples of such photoacid generators include onium salts (diazonium salts, sulfonium salts, iodonium salts, selenium salts, pyridinium salts, iron-cerium alginate salts, phosphonium salts, etc.) formed from anionic and cationic components such as SbF6-, PF6-, BF4-, AsF6-, (C6F5)4-, and PF4(CF2CF3)2-. They can be used alone or in combination of two or more. Specifically, examples include aromatic sulfonium salts, aromatic iodonium salts, aromatic phosphonium salts, and aromatic oxide sulfonium salts.

[0173] [Method for manufacturing crosslinking agent component (B)]

[0174] When the crosslinking agent component (B) is an aliphatic or alicyclic polyisocyanate (b), the above-mentioned diisocyanate (b1) is reacted with a polyol (b2) to obtain the product.

[0175] During the reaction, the molar ratio of the isocyanate group of the diisocyanate to the hydroxyl group of the polyol (b2) (isocyanate group / hydroxyl group molar ratio) is preferably 1.5 or more and 30.0 or less, more preferably 2.0 or more and 25.0 or less, even more preferably 2.2 or more and 22.0 or less, and even more preferably 2.5 or more and 22.0 or less. By keeping the NCO / OH ratio within the above-mentioned range, the crosslinking agent component (B) can be synthesized without gelation. For the resulting optical resin sheet, the adhesion can be further improved, the elastic modulus can be further reduced, the elongation can be further increased, the tensile strength and durability can be further improved, and the bending resistance can be improved.

[0176] The reaction between the polyol and the diisocyanate is carried out as described below. The reaction temperature is typically above room temperature (around 23°C) and below 200°C, preferably above 60°C and below 170°C, and more preferably above 60°C and below 165°C. If the reaction temperature is above the lower limit mentioned above, the reaction time becomes shorter; on the other hand, if it is below the upper limit mentioned above, the increase in viscosity of the polyisocyanate due to undesirable side reactions can be further avoided, and the coloring of the resulting polyisocyanate can also be further avoided.

[0177] The reaction can be carried out under solvent-free conditions or with any solvent that is inactive with respect to the isocyanate group. Additionally, if necessary, a known catalyst can be used to promote the reaction between the isocyanate group and the hydroxyl group.

[0178] [Physical properties of crosslinking agent component (B)]

[0179] The isocyanate group content (NCO group content) of the crosslinking agent component (B), in a substantially solvent-free and diisocyanate-free state, is preferably 1.0% by mass or more and 9.5% by mass or less relative to the total mass of the crosslinking agent component (B), more preferably 1.5% by mass or more and 9.0% by mass or less, further preferably 2.0% by mass or more and 8.7% by mass or less, even more preferably 2.0% by mass or more and 8.5% by mass or less, particularly preferably 2.5% by mass or more and 8.3% by mass or less, and most preferably 2.8% by mass or more and 8.3% by mass or less.

[0180] The NCO group content can be determined, for example, by reacting the isocyanate groups in the crosslinking agent component (B) with an excess of amine (such as dibutylamine), and then back-titrifying the residual amine with an acid such as hydrochloric acid.

[0181] The crosslinking agent component (B) is applied only to the release film, and the film is stored at 23°C and 65% humidity for 168 hours, followed by heating at 50°C for 24 hours. The resulting 50 μm thick cured film is then peeled off the release film and cut into pieces 10 mm wide and 40 mm long. These pieces are then placed in a tensile testing machine with a 20 mm gap between clamps. A tensile test is performed at 23°C and a speed of 20 mm / min. The elongation at this point is preferably 100% or more, more preferably 150% or more, further preferably 170% or more, and even more preferably 200% or more. By achieving an elongation at or above the lower limit mentioned above, excellent flexibility, bending resistance, and adhesion are achieved.

[0182] In addition, the higher the upper limit of the tensile elongation, the better; for example, it can be set to 1500% or 2000%.

[0183] The aforementioned crosslinking agent component (B) is applied only to the release film, and the film is stored at 23°C and 65% humidity for 168 hours, followed by heating at 50°C for 24 hours. The resulting 50 μm thick cured film is then peeled off from the release film and cut into pieces 10 mm wide and 40 mm long. These pieces are then placed in a tensile testing machine with a 20 mm gap between the clamps. The tensile strength in a tensile test performed at 23°C and 20 mm / min is preferably 2 MPa or more and 100 MPa or less, more preferably 5 MPa or more and 80 MPa or less, and even more preferably 10 MPa or more and 75 MPa or less. By maintaining the tensile strength within the above range, the adhesion, holding power, and flexural strength are improved.

[0184] The crosslinking agent component (B) is applied only to the release film, and the film is stored at 23°C and 65% humidity for 168 hours, followed by heating at 50°C for 24 hours. For the cured film with a thickness of 50 μm formed therefrom, the haze value measured by a haze meter is preferably 3.0% or less. By keeping the haze value below the above-mentioned upper limit, the transparency is better.

[0185] In addition, the lower the lower limit of the haze value, the better; for example, it can be set to 0.0%.

[0186] [Content of cross-linking agent component (B)]

[0187] The content of the crosslinking agent component (B) relative to 100 parts by weight of the polymer (A) is preferably 0.01 parts by weight or more and 80.0 parts by weight or less, more preferably 0.03 parts by weight or more and 40.0 parts by weight or less, and even more preferably 0.05 parts by weight or more and 30.0 parts by weight or less. By keeping the content of the crosslinking agent component (B) within the above-mentioned range, there is a tendency for the curability, transparency, flexural strength, adhesion, and holding power to be better when producing optical resin sheets. The content of the crosslinking agent component (B) can be calculated based on, for example, the amount of crosslinking agent component (B) used in the manufacture of optical resin compositions.

[0188] [Isocyanate group / crosslinking functional group]

[0189] The molar ratio of isocyanate groups of the crosslinking agent component (B) to the crosslinking functional groups (especially hydroxyl groups) of the polymer (A) in the optical resin composition of this embodiment (molar ratio of isocyanate groups / crosslinking functional groups) is determined according to the physical properties of the desired optical resin sheet, and is generally 0.01 or more and 50 or less.

[0190] <Other Ingredients>

[0191] In the optical resin composition of this embodiment, relative to 100 parts by weight of polymer (A), it may further contain 0.01 parts by weight and 0.50 parts by weight of silane coupling agent (C). By containing silane coupling agent (C) in the above-mentioned numerical range, the optical resin composition of this embodiment can further improve the adhesion of the resulting optical resin sheet and further suppress lifting and peeling at the interface of the adhered objects during heating and humidification.

[0192] As a silane coupling agent (C), it is not limited to the following substances, but may include, for example, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, ureapropyltriethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, etc.

[0193] The content of silane coupling agent (C) relative to 100 parts by mass of polymer (A) is preferably 0.01 parts by mass or more and 0.50 parts by mass or less, more preferably 0.05 parts by mass or more and 0.45 parts by mass or less, and even more preferably 0.05 parts by mass or more and 0.40 parts by mass or less.

[0194] The optical resin composition of this embodiment may further contain other additives.

[0195] Other additives include, for example, curing catalysts, solvents, pigments (extender pigments, coloring pigments, metallic pigments, etc.), tackifying resins, photopolymerization initiators, ultraviolet absorbers, light stabilizers, free radical stabilizers, anti-yellowing agents that inhibit coloring during the sintering process, coating surface conditioners, flow conditioners, pigment dispersants, defoamers, thickeners, and film-forming aids.

[0196] The aforementioned curing catalyst can be either a basic compound or a Lewis acid compound.

[0197] Examples of the aforementioned basic compounds include, for example, metal hydroxides, metal alkoxides, metal carboxylates, metal acetylacetonates, hydroxides of onium salts, onium carboxylates, halides of onium salts, metal salts of active methylene compounds, onium salts of active methylene compounds, aminosilanes, amines, and phosphines. Among the aforementioned onium salts, ammonium salts, phosphonium salts, or sulfonium salts are suitable.

[0198] Examples of Lewis acidic compounds include organotin compounds, organozinc compounds, organotitanium compounds, and organozirconium compounds.

[0199] Examples of solvents mentioned above include 1-methylpyrrolidone, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether, 3-methoxy-3-methyl-1-butanol, ethylene glycol diethyl ether, diethylene glycol diethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether (DPDM), propylene glycol dimethyl ether, methyl ethyl ketone, etc. Acetone, methyl isobutyl ketone, propylene glycol monomethyl ether acetate, ethanol, methanol, isopropanol, 1-propanol, isobutanol, 1-butanol, tert-butanol, 2-ethylhexanol, cyclohexanol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, ethyl acetate, isopropyl acetate, butyl acetate, toluene, xylene, pentane, isopentane, hexane, isohexane, cyclohexane, naphtha, mineral oil, etc. These solvents can be used individually or in combination of two or more.

[0200] In addition, known substances can be appropriately selected and used as pigments (extender pigments, coloring pigments, metallic pigments, etc.), ultraviolet absorbers, light stabilizers, free radical stabilizers, anti-yellowing agents that inhibit coloring during the sintering process, coating surface conditioners, flow conditioners, pigment dispersants, defoamers, thickeners, and film-forming aids.

[0201] Optical Resin Composition 2

[0202] The optical resin composition of this embodiment includes a polymer (A) and a crosslinking agent component (B).

[0203] Polymer (A) is one or more polymers selected from the group consisting of acrylic polymers, urethane polymers and rubber polymers.

[0204] The glass transition temperature (Tg) of polymer (A) is -110.0°C or higher and -10.0°C or lower, preferably -105.0°C or higher and -15.0°C or lower, more preferably -105.0°C or higher and -20.0°C or lower, even more preferably -100.0°C or higher and -25.0°C or lower, and particularly preferably -100.0°C or higher and -40.0°C or lower. By ensuring that the glass transition temperature (Tg) of polymer (A) is within the above range, there is a tendency for it to exhibit excellent adhesion and flexural strength when manufactured into optical resin sheets.

[0205] Regarding the glass transition temperature of polymer (A), for example, for a substance obtained by vacuum drying after removing organic solvent and water from a solution in which polymer (A) is dissolved or dispersed under reduced pressure, a differential scanning calorimeter (DSC) is used to measure the glass transition temperature at a heating rate of 5°C / min, and the value obtained is used as the glass transition temperature.

[0206] The aforementioned crosslinking agent component (B) comprises at least one diisocyanate (b1) selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, and a polyisocyanate derived from a polyol (b2) having a number average molecular weight of 1100 or more and an average number of hydroxyl groups of 1.5 or more and 2.5 or less.

[0207] The molar ratio of the isocyanate group of the aforementioned diisocyanate (b1) to the total molar amount of the hydroxyl group of the aforementioned polyol (b2), NCO / OH, is 1.5 or more and 30.0 or less.

[0208] The aforementioned polyisocyanates have a weight-average molecular weight of 2100 or more and 200,000 or less.

[0209] The optical resin composition of this embodiment, by having the above-described structure, enables the production of an optical resin sheet that maintains good transparency while exhibiting excellent adhesion, holding power, flexural strength, and durability. It should be noted that the flexural strength mentioned here, as shown in the examples described later, is evaluated using elastic modulus, maximum stress, and elongation for simplicity. This is characterized by a low elastic modulus (Young's modulus), high elongation, and high maximum stress in the layer formed by curing the optical resin composition. In other words, a material that readily follows deformation caused by bending, easily relaxes stress, and is difficult to break (high maximum stress) exhibits excellent flexural strength. A preferred range for the elastic modulus is described later.

[0210] <Polymer (A)>

[0211] The polymer (A) in this embodiment is as described in <Polymer (A)> of the above-mentioned "Optical Resin Composition 1".

[0212] <Crosslinking agent component (B)>

[0213] The crosslinking agent component (B) in this embodiment comprises at least one diisocyanate (b1) selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, and a polyisocyanate (b) derived from a polyol (b2) having a number average molecular weight of 1100 or more and an average number of hydroxyl groups of 1.5 or more and 2.5 or less.

[0214] The content of polyisocyanate (b) in the crosslinking agent component (B) relative to the total mass of the crosslinking agent component (B) is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 90% by mass or more, and particularly preferably 100% by mass. By making the content of polyisocyanate (b) in the crosslinking agent component (B) at or above the above-mentioned lower limit value, the effects of the optical resin composition of this embodiment can be more fully exerted.

[0215] The molar ratio of the isocyanate groups of the aforementioned diisocyanate (b1) to the total molar ratio of the hydroxyl groups of the aforementioned polyol (b2), NCO / OH, is 1.5 or more and 30.0 or less, preferably 2.0 or more and 25.0 or less, and more preferably 2.2 or more and 22.0 or less. By keeping the NCO / OH ratio within the above-mentioned range, it is possible to synthesize the crosslinking agent component (B) without gelation. For the resulting optical resin sheet, the adhesive strength can be further improved, the elastic modulus can be further reduced, the elongation can be further increased, and the tensile strength can be further improved.

[0216] The weight-average molecular weight Mw(b) of the polyisocyanate (b) is 2100 or more and 200,000 or less, preferably 2500 or more and 200,000 or less, more preferably 3000 or more and 200,000 or less, even more preferably 3000 or more and 180,000 or less, further preferably 3000 or more and 150,000 or less, and particularly preferably 3200 or more and 150,000 or less. By ensuring that the weight-average molecular weight Mw(b) of the polyisocyanate (b) is within the above-mentioned range, the resulting optical resin sheet can be further improved in terms of adhesive strength, further reduced in terms of elastic modulus (Young's modulus), further increased in terms of elongation, further improved in terms of tensile strength, and improved in terms of flexural strength.

[0217] The Mw(b) of the polyisocyanate(b) is the weight-average molecular weight based on polystyrene as determined by GPC.

[0218] The average number of isocyanate groups in the polyisocyanate (b) is 1.5 or more and 5.2 or less, more preferably 1.7 or more and 5.2 or less, and even more preferably 1.8 or more and 5.2 or less. By ensuring that the average number of isocyanate groups in the polyisocyanate (b) is within the above-mentioned range, the polymer (A) and the crosslinking agent component (B) can more effectively form a crosslinking network. For the resulting optical resin sheet, the adhesive strength can be further improved, the elastic modulus can be further reduced, the elongation can be further increased, the bending resistance can be improved, and the breaking strength can be further improved.

[0219] The average number of isocyanate groups (fn) of polyisocyanate (b) can be calculated using the following formula. In the formula, "Mn" represents the number-average molecular weight of polyisocyanate (b), and "NCO%" represents the isocyanate group content of polyisocyanate (b). The number-average molecular weight Mn of polyisocyanate (b) is the weight-average molecular weight based on polystyrene as determined by GPC. The method for determining NCO% is described below.

[0220] [fn] = [Mn] × [NCO%] / 4200

[0221] The polyisocyanate (b) may have one or more functional groups selected from the group consisting of urea-formate, urea-diketone, iminooxadiazine-diketone, isocyanurate, urea, carbamate, and biuret. Preferably, it has one or more functional groups selected from the group consisting of urea-formate, urea-diketone, isocyanurate, urea, carbamate, and biuret; more preferably, it has one or more functional groups selected from the group consisting of urea-formate, urea-diketone, urea, and carbamate.

[0222] In the crosslinking agent component (B), the molar ratio of isocyanurate groups relative to the total molar amount of urea carbamate groups, urea diketone groups, iminooxadiazine diketone groups, isocyanurate groups, urea groups, carbamate groups, and biuret groups is preferably 50 mol% or less, more preferably 45 mol% or less, further preferably 40 mol% or less, and particularly preferably less than 35 mol%. By keeping the molar ratio of isocyanurate groups below the above-mentioned upper limit, an optical resin composition with superior flexibility can be obtained.

[0223] Furthermore, the polyisocyanate (b) preferably also contains structural units derived from monools, diols, or polyoxyalkylene alkyl ethers having 2 or more but less than 18 carbon atoms. By including structural units derived from monools or diols, optical resin compositions with higher elongation and greater tensile strength can be obtained.

[0224] Monools that can serve as the source of the aforementioned structural units include, for example, methanol, ethanol, propanol (various isomers), butanol (various isomers including isobutanol), pentanol (various isomers), hexanol (various isomers), heptanol (various isomers), octanol (various isomers), nonanol (various isomers), stearyl alcohol (various isomers including isostearyl alcohol), etc.

[0225] Examples of diols that can serve as the source of the aforementioned structural units include ethylene glycol, 1,3-butanediol, neopentyl glycol, and 2-ethylhexanediol.

[0226] Examples of polyoxyalkylene alkyl ethers that serve as the source of the aforementioned structural units include, for example, polyoxyethylene alkyl ethers, polyoxypropylene alkyl ethers, and polyoxyethylene polyoxypropylene alkyl ethers.

[0227] Preferably, butanol (including isobutanol and its isomers), octanol (including its isomers), stearyl alcohol (including isostearyl alcohol and its isomers), or 1,3-butanediol are used; more preferably, isobutanol, isostearyl alcohol, 2-ethylhexanol, 1,3-butanediol, or polyoxyalkylene alkyl ethers are used.

[0228] [Diisocyanate (b1)]

[0229] Diisocyanate (b1) is selected from at least one of the groups consisting of aliphatic diisocyanates and alicyclic diisocyanates.

[0230] Aliphatic diisocyanates are not limited to the following substances, but may include, for example, 1,4-diisocyanate butane, 1,5-diisocyanate pentane (hereinafter sometimes abbreviated as "PDI"), ethyl (2,6-diisocyanate)hexanoate, 1,6-diisocyanate hexane (hereinafter sometimes abbreviated as "HDI"), 1,7-diisocyanate heptane, 1,8-diisocyanate octane, 1,9-diisocyanate nonane, 1,12-diisocyanate dodecane, 2,2,4- or 2,4,4-trimethyl-1,6-diisocyanate hexane, etc. These aliphatic diisocyanates can be used alone or in combination of two or more.

[0231] As alicyclic diisocyanates, not limited to the following substances, examples include 1,3- or 1,4-bis(isocyanate methyl)cyclohexane (hereinafter sometimes abbreviated as "hydrogenated XDI"), 1,3- or 1,4-diisocyanate cyclohexane, 3,5,5-trimethyl-1-isocyanate methyl-3-(isocyanate methyl)cyclohexane (hereinafter sometimes abbreviated as "IPDI"), 4-4'-diisocyanate methyl-dicyclohexylmethane (hereinafter sometimes abbreviated as "hydrogenated MDI"), 2,5- or 2,6-diisocyanate methyl norbornene, etc. These alicyclic diisocyanates can be used alone or in combination of two or more.

[0232] These aliphatic and alicyclic diisocyanates can be used alone or in combination of two or more.

[0233] Furthermore, from the viewpoint of flexibility, the mass ratio of alicyclic diisocyanate (b) to aliphatic diisocyanate is preferably 0 / 100 or more and 30 / 70 or less, more preferably 0 / 100 or more and 20 / 80 or less.

[0234] The preferred diisocyanate is 1,4-diisocyanate butane, PDI, HDI, 1,7-diisocyanate heptane, 1,8-diisocyanate octane, IPDI, hydrogenated XDI, or hydrogenated MDI, more preferably PDI, HDI, or IPDI, and even more preferably PDI or HDI.

[0235] In the manufacture of polyisocyanate (b), an isocyanate monomer as shown below can be further used in addition to the diisocyanate described above.

[0236] (1) Aromatic diisocyanates such as diphenylmethane-4,4'-diisocyanate (MDI), 1,5-naphthalene diisocyanate, toluene diisocyanate (TDI), phenylmethylene diisocyanate (XDI), and m-tetramethylphenylmethylene diisocyanate (TMXDI).

[0237] (2) Triisocyanates such as 4-isocyanate methyl-1,8-octamethylene diisocyanate (hereinafter sometimes referred to as "NTI"), 1,3,6-hexamethylene triisocyanate (hereinafter sometimes referred to as "HTI"), bis(2-isocyanate ethyl) 2-isocyanate glutarate (hereinafter sometimes referred to as "GTI"), and lysine triisocyanate (hereinafter sometimes referred to as "LTI").

[0238] [Polyol (b2)]

[0239] The polyol (b2) has a number average molecular weight of 1100 or more, and an average number of hydroxyl groups of 1.5 or more and 2.5 or less.

[0240] The number average molecular weight of the polyol (b2) is 1100 or more, more preferably 1400 or more, and even more preferably 1800 or more. By making the number average molecular weight of the polyol (b2) above the above lower limit, the cured film formed by curing only the polyisocyanate (b) has low hardness, high elongation, and good flexibility.

[0241] On the other hand, there is no particular limitation on the upper limit of the number average molecular weight of the polyol (b2). For example, it can be set to 12,000, preferably 11,000, more preferably 10,000, even more preferably 9,000, even more preferably 8,000, even more preferably 7,000, particularly preferably 6,000, even more particularly preferably 5,000, and most preferably 4,200.

[0242] The number-average molecular weight Mn of the polyol (b2) is, for example, the number-average molecular weight of polystyrene based on GPC. Furthermore, when two or more polyols (b2) are mixed, the number-average molecular weight of the mixture is calculated.

[0243] As the polyol (b2), it is preferably at least one polyol selected from the group consisting of polyester polyol, polyether polyol, epoxy polyol, polyolefin polyol and polycarbonate polyol, more preferably polyolefin polyol, polyether polyol or polyester polyol, and even more preferably polyester polyol.

[0244] Examples of polyester polyols include any of the following (1) or (2).

[0245] (1) A polyester polyol obtained by condensation reaction of one or more dicarboxylic acids with one or more diols.

[0246] (2) Polycaprolactone polyol obtained by ring-opening polymerization of ε-caprolactone using diol.

[0247] Examples of the aforementioned dicarboxylic acids include succinic acid, adipic acid, dimer acids, maleic anhydride, phthalic anhydride, isophthalic acid, terephthalic acid, and 1,4-cyclohexanedicarboxylic acid.

[0248] Examples of the aforementioned diols include ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, trimethylpentanediol, and cyclohexanediol.

[0249] Among them, polycaprolactone polyol is preferred as the polyester polyol.

[0250] Commercially available polycaprolactone polyols include, for example, those manufactured by Daicel under the trade names "PLACCEL212" (number average molecular weight 1250, hydroxyl value 90.8 mgKOH / g, acid value 0.09 mgKOH / g), "PLACCEL212CP" (number average molecular weight 1250, hydroxyl value 90.2 mgKOH / g, acid value 0.14 mgKOH / g), "PLACCEL 220" (number average molecular weight 2000, hydroxyl value 56.7 mgKOH / g, acid value 0.06 mgKOH / g), "PLACCEL 220CPB" (number average molecular weight 2000, hydroxyl value 57.2 mgKOH / g, acid value 0.16 mgKOH / g), "PLACCEL220CPT" (number average molecular weight 2000, hydroxyl value 56.6 mgKOH / g, acid value 0.02 mgKOH / g), and "PLACCEL...". "230" (number average molecular weight of 3000, hydroxyl value of 37.6 mgKOH / g, acid value of 0.07 mgKOH / g), "PLACCEL 240" (number average molecular weight of 4000, hydroxyl value of 28.5 mgKOH / g, acid value of 0.07 mgKOH / g), etc.

[0251] From the viewpoint of hydrolysis resistance and reaction stability during the synthesis of polyisocyanates (b), polycaprolactone polyols with difunctionality are preferred to use substances with lower acid values.

[0252] In the polyisocyanate (b), the content (feed amount) of polyol (b2) relative to 100 parts by mass of diisocyanate (b1) is generally preferably 0.1 parts by mass or more and 900.0 parts by mass or less, more preferably 1.0 parts by mass or more and 850.0 parts by mass or less, and even more preferably 2.0 parts by mass or more and 800.0 parts by mass or less.

[0253] By keeping the content of polyol (b2) below the aforementioned upper limit, the polyisocyanate (b) can be maintained in a liquid state without gelation during manufacturing, resulting in better curability and flexibility when used to produce optical resin sheets. Conversely, by keeping the content of polyol (b2) above the aforementioned lower limit, the cured film formed by curing polyisocyanate (b) alone has lower hardness and better flexibility. Furthermore, optical resin sheets with superior adhesion, flexural strength, and durability can be obtained.

[0254] The content of polyol (b2) can be calculated based on, for example, the amount of diisocyanate and polyol (b2) mixed when manufacturing polyisocyanate (b).

[0255] [Other cross-linking agent components]

[0256] The crosslinking agent component (B) may, in addition to including the above-mentioned polyisocyanate (b), also include one or more other crosslinking agent components (b') selected from the group consisting of isocyanate compounds, carbodiimide compounds, oxazoline compounds, polyfunctional acrylate monomers, peroxides, epoxy crosslinking agents, titanium coupling agents, zirconium compounds, aluminum chelates, acyl hydrazine compounds, thermal acid-producing agents, and photoacid-producing agents.

[0257] The other crosslinking agent component (b') in this embodiment is as described in [Other Crosslinking Agent Components] of <Crosslinking Agent Component (B)> of the above-mentioned "Optical Resin Composition 1".

[0258] [Manufacturing method, physical properties, and content of crosslinking agent component (B)]

[0259] The manufacturing method, physical properties, and content of the crosslinking agent component (B) in this embodiment are as described in the [Manufacturing method of crosslinking agent component (B)], [Physical properties of crosslinking agent component (B)], and [Content of crosslinking agent component (B)] of the above-mentioned "Optical Resin Composition 1" <Crosslinking agent component (B)>.

[0260] [Isocyanate group / crosslinking functional group]

[0261] The isocyanate group / crosslinking functional group in this embodiment is as described in the [isocyanate group / crosslinking functional group] of the <crosslinking agent component (B)> of the above-mentioned "Optical Resin Composition 1".

[0262] <Other Ingredients>

[0263] The other components in this embodiment are as described in <Other Components> of the above-mentioned "Optical Resin Composition 1".

[0264] Method for manufacturing optical resin compositions

[0265] Optical resin compositions can be manufactured using existing known methods. These include melt mixing methods using general mixers such as Banbury internal mixers, single-screw extruders, twin-screw extruders, co-kneaders, and multi-screw extruders; and methods where the components are dissolved or dispersed and then coated onto a substrate film using a coating machine, followed by solvent removal by heating.

[0266] Resin sheets for optical applications

[0267] The optical resin sheet of this embodiment is formed by curing the above-mentioned optical resin composition using heat or light.

[0268] The optical resin sheet of this embodiment has good transparency and excellent adhesion, holding power, bending resistance and durability.

[0269] The thickness of the optical resin sheet in this embodiment can be appropriately determined according to the application, preferably 1 μm or more and 1000 μm or less, more preferably 3 μm or more and 900 μm or less, further preferably 5 μm or more and 800 μm or less, even more preferably 5 μm or more and 700 μm or less, and particularly preferably 7 μm or more and 700 μm or less.

[0270] The optical resin sheet of this embodiment can be manufactured, for example, by coating the above-described optical resin composition onto a substrate, drying it as needed, and then curing it.

[0271] The substrate is not particularly limited, and examples include, for instance, high-quality paper, coated paper, cast coated paper, thermal paper, inkjet paper, etc.; woven fabrics, non-woven fabrics, etc.; resin films such as polyvinyl chloride, synthetic paper, polyethylene terephthalate (PET), polypropylene, polyethylene, cellulose triacetate, cellulose diacetate, polystyrene, polycarbonate, nylon, polyvinyl alcohol, ethylene-vinyl acetate copolymer, polyimide, etc.; porous resin films such as porous polypropylene films; vapor-deposited films such as PET and polyolefins obtained by metal vapor deposition of aluminum; and metal foils, etc. The substrate can also be a substrate obtained by performing a surface peeling treatment.

[0272] As a method for coating an optical resin composition onto a substrate, examples include coating using a coater, roller coater, knife coater, gravure coater, etc. After coating, drying can be performed, for example, by placing the resulting laminate into a dryer and drying it at a temperature of, for example, 50°C or higher and 150°C or lower for 1 minute or more and 30 minutes or less. Alternatively, other drying methods include, for example, natural drying, hot air drying, infrared drying, etc.

[0273] The heating temperature for curing can be set to 70°C or higher and 150°C or lower, 75°C or higher and 145°C or lower, or 80°C or higher and 140°C or lower.

[0274] Regarding the optical resin sheet of this embodiment, an optical resin sheet having a polyethylene terephthalate film on one side, a resin thickness of 50 μm, a width of 20 mm, and a length of 100 mm, is pressed onto an SUS304BA board as the substrate by a 2 kg roller in one round trip. After curing at 23°C for 30 minutes, the 180-degree peel adhesion force measured at 23°C and a speed of 300 mm / min is preferably 1.0 N / 20 mm or more and 100.0 N / 20 mm or less, preferably... The optical resin sheet is obtained by coating the aforementioned optical resin composition onto a polyethylene terephthalate film with a thickness of 25 μm, curing it by drying at 125°C for 3 minutes, and then storing it at 23°C and 50% RH for 7 days. The lower limit of the 180° peel adhesion is further preferably 3.0 N / 20 mm, particularly preferably 4.0 N / 20 mm. Furthermore, the upper limit of the 180° peel adhesion is particularly preferably 80 N / 20 mm. By setting the 180° peel adhesion to the aforementioned lower limit or above, the adhesion is more superior.

[0275] Regarding the optical resin sheet of this embodiment, an optical resin sheet with a single-sided polyethylene terephthalate film having a resin thickness of 50 μm, a width of 25 mm, and a length of 130 mm is pressed onto an SUS304BA board (the substrate) with the width and length directions overlapping by one round trip using a 2 kg roller. The sheet is cured at 23°C for 1 hour, further cured at 40°C for 30 minutes, and then a 500 g weight is applied at 40°C. After suspending the aforementioned optical resin sheet at its lower end for 1 hour and then restoring it to a 23°C environment, the offset of the aforementioned optical resin sheet is preferably 2.00 mm or less, more preferably 1.00 mm or less, and even more preferably 0.50 mm or less. The optical resin sheet is obtained as follows: the aforementioned optical resin composition is coated on the aforementioned polyethylene terephthalate film with a thickness of 25 μm, dried at 125°C for 3 minutes to cure it, and then stored at 23°C and 50% RH for 7 days. By keeping the offset below the aforementioned upper limit value, the holding force (cohesive force) is more excellent.

[0276] In addition, the smaller the lower limit of the offset, the better; it can be set to, for example, 0.00mm.

[0277] Regarding the optical resin sheet of this embodiment, the above-mentioned optical resin composition is coated onto a 38 μm thick polyethylene terephthalate film that has undergone peeling treatment. After curing by drying at 125°C for 3 minutes, it is stored at 23°C and 50% RH for 7 days. The resulting 50 μm thick optical resin sheet is then peeled off from the aforementioned peeled polyethylene terephthalate film and adhered to a glass with a haze value of 0.1%. The haze value measured using a haze meter is preferably 2.0% or less, more preferably 1.0% or less, and even more preferably 0.9% or less. By keeping the haze value below the above-mentioned upper limit, the transparency is more excellent.

[0278] In addition, the lower the lower limit of the haze value, the better; it can be set to, for example, 0.1%.

[0279] Regarding the optical resin sheet of this embodiment, the above-mentioned optical resin composition is coated onto a 38 μm thick peel-treated polyethylene terephthalate film, dried at 125°C for 3 minutes to cure it, and then stored at 23°C and 50% RH for 7 days. After peeling it off from the aforementioned peel-treated polyethylene terephthalate film, the resulting 50 μm thick optical resin sheet is stored at 23°C and 50% RH for 7 days, wrapped with a #400 mesh sheet, immersed in ethyl acetate at 23°C for 1 week, and then dried at 120°C for 2 hours. The gel fraction calculated therefrom is preferably 45.0% by mass or more and 99.9% by mass or less, more preferably 55.0% by mass or more and 99.9% by mass or less, further preferably 58.0% by mass or more and 99.9% by mass or less, and even more preferably 60.0% by mass or more and 99.9% by mass or less. By setting the gel fraction above the aforementioned lower limit, superior adhesion, cohesion, moisture and heat resistance, and flexural strength are achieved.

[0280] It should be noted that the gel fraction mentioned here is the percentage of the mass of the aforementioned optical resin sheet after impregnation in ethyl acetate and subsequent drying, relative to the mass of the aforementioned optical resin sheet before impregnation in ethyl acetate.

[0281] Regarding the optical resin sheet of this embodiment, the above-mentioned optical resin composition is coated onto a 38 μm thick peel-treated polyethylene terephthalate film, dried at 125°C for 3 minutes to cure it, and then stored at 23°C and 50% RH for 7 days. The resulting 50 μm thick optical resin sheet is then peeled off from the peel-treated polyethylene terephthalate film, and the resulting 50 μm thick optical resin sheet is stacked with a thickness of 200 μm. It is then cut into pieces 10 mm wide and 40 mm long, and placed in a tensile testing machine with a 10 mm gap between clamps. The elastic modulus (Young's modulus) in a tensile test performed at 23°C and 300 mm / min is preferably 0.40 N / mm². 2 The following, or more preferably, is 0.30 N / mm 2 The following, and more preferably, is 0.20 N / mm 2 The following, and more preferably, is 0.25 N / mm 2 The following is an example. By setting the elastic modulus below the aforementioned upper limit, superior flexibility, adhesion, and flexural strength are achieved.

[0282] Furthermore, a lower limit for the elastic modulus is preferred when it is in the cross-linked state; for example, it can be set to 0.01 N / mm. 2 It can be set to 0.02 N / mm. 2 .

[0283] Furthermore, the elongation in the tensile test is preferably 100% or more, more preferably 150% or more, even more preferably 200% or more, more preferably 230% or more, and particularly preferably 250% or more. By ensuring that the tensile elongation is above the aforementioned lower limit value, the flexibility, adhesion, and bending resistance are further improved.

[0284] In addition, the higher the upper limit of the tensile elongation, the better; for example, it can be set to 5000%.

[0285] The optical resin sheet of this embodiment, as described above, has good transparency and excellent adhesion, holding power, bending resistance and durability. Therefore, it can be suitable for use as, for example, an optical transparent adhesive sheet (OCA) or an optical transparent adhesive sheet (OCR).

[0286] Example

[0287] The present invention will be described below by way of examples, but the present invention is not limited to the following examples.

[0288] [Physical properties 1]

[0289] (Glass transition temperature Tg)

[0290] Regarding the glass transition temperature of polymer (A), the organic solvent and water in the solution of polymer (A) were removed under reduced pressure and then vacuum dried. The resulting substance was measured using a differential scanning calorimeter (DSC) at a heating rate of 5 °C / min, and the value obtained was used as the glass transition temperature.

[0291] [Physical Properties 2]

[0292] (Number average molecular weight and weight average molecular weight)

[0293] The number-average molecular weight and weight-average molecular weight are polystyrene-based molecular weights determined by gel permeation chromatography (GPC) using the apparatus described below.

[0294] (Measurement conditions)

[0295] Device: Tosoh Corporation, HLC-802A

[0296] Column: Tosoh Corporation, G1000HXL x 1 piece

[0297] G2000HXL × 1 piece

[0298] G3000HXL × 1 piece

[0299] Support: Tetrahydrofuran

[0300] Test method: Differential refractometer

[0301] [Physical Properties 3]

[0302] (Isocyanate group content)

[0303] First, accurately weigh 2g but less than 3g of the test sample (Wg) into a flask. Next, add 20mL of toluene to dissolve the test sample. Then, add 20mL of a toluene solution containing 2 equivalents of di-n-butylamine and mix, allowing to stand at room temperature for 15 minutes. Next, add 70mL of isopropanol and mix. Then, titrate the liquid with an indicator using a hydrochloric acid solution containing 1 equivalent (factor F). Record the resulting titration value as V2mL. Next, record the titration value obtained without the sample as V1mL. Then, calculate the isocyanate group content (NCO%) (mass%) of the crosslinking agent component (B) according to the following formula.

[0304] "Isocyanate group content (mass%)" = (V1-V2)×F×42 / (W×1000)×100

[0305] [Physical Properties 4]

[0306] (Average number of isocyanate functional groups)

[0307] The average number of isocyanate functional groups (average NCO number) of the crosslinking agent component (B) is calculated using the following formula. It should be noted that in the formula, "Mn" is the exponential average molecular weight, using the value measured in "Property 2" above. "NCO%" uses the value calculated in "Property 3" above.

[0308] "Average number of isocyanate functional groups" = (Mn × NCO% × 0.01) / 42

[0309] [Preparation of a cured film using crosslinking agent component (B)]

[0310] For each crosslinking agent component (B), 0.1% by mass of dioctyltin catalyst was added and mixed. After degassing, the mixture was applied to the release film using a spreader. After being stored at 23°C and 65% humidity for 168 hours, it was further heated at 50°C for 24 hours to obtain a cured film with a thickness of 50 μm.

[0311] [Property 5]

[0312] (Tension elongation and tensile strength)

[0313] For each crosslinking agent component (B), the cured film is peeled off from the release film and cut into pieces 10 mm wide and 40 mm long. Then, the pieces are placed in a tensile testing machine with a clamping distance of 20 mm, and the tensile elongation and tensile strength are measured at 20 mm / min in an environment of 23°C.

[0314] [Physical Properties 6]

[0315] (Haze)

[0316] For each cured film, it was peeled off from the release film to create a test piece. Then, for this test piece, a haze meter (HMG-2DP) manufactured by SugaTest Instruments was used to measure the haze on the peeled side of the test piece, which was positioned facing the light source between the two sides of the test piece.

[0317] <Evaluation Methods>

[0318] [Fabrication of Optical Resin Sheet 1]

[0319] Using a spreader, each optical resin composition was applied to a 25 μm thick polyethylene terephthalate (PET) film to achieve a 50 μm thickness of dried resin layer. The film was then dried at 125°C for 3 minutes. Subsequently, it was stored at 23°C and 50% RH for 7 days for applications including 180° peel strength testing, holding power testing, and durability testing, resulting in optical resin sheet 1.

[0320] [Fabrication of Optical Resin Sheet 2]

[0321] Using a spreader, each optical resin composition was applied to a 38 μm thick, peel-treated PET film to a dry thickness of 50 μm, and dried at 125°C for 3 minutes. Subsequently, it was stored at 23°C and 50% RH for 7 days for gel fraction determination, haze measurement, and tensile testing, resulting in optical resin sheet 2.

[0322] [Rating 1]

[0323] (180-degree peel adhesion)

[0324] The optical resin sheet 1 obtained in the above-mentioned "Preparation of optical resin sheet 1" was cut into pieces with a width of 20 mm and a length of 100 mm to obtain a test piece. Next, regarding the test piece, a 2 kg roller was used to press the test piece onto the SUS304BA board, which serves as the substrate, by moving it back and forth once. After curing at 23°C for 30 minutes, the 180-degree peel adhesion was measured using a tensile testing machine at a speed of 300 mm / min.

[0325] Regarding Examples 1-1 to 1-14 and Comparative Examples 1-1 to 1-4, samples with a strength of 3.5 N / 20 mm or higher were evaluated as having good adhesion.

[0326] Regarding Examples 2-1 to 2-20 and Comparative Examples 2-1 to 2-4, samples with adhesion strength of 2.0 N / 20 mm or more and 100.0 N / 20 mm or less were evaluated as having good adhesion.

[0327] [Rating 2]

[0328] (Holding force)

[0329] The optical resin sheet 1 obtained in the above-mentioned "Preparation of Optical Resin Sheet 1" was cut into pieces with a width of 25 mm and a length of 130 mm to obtain a test piece. Next, using a 2 kg roller, the test piece was pressed onto the SUS304BA board (the substrate) with the width and length overlapping in a 25 mm range, and then cured at 23°C for 30 minutes, followed by a further curing at 40°C for 30 minutes. Afterward, a 500 g weight was suspended from the lower end of the test piece at 40°C for 1 hour, and then the temperature was returned to 23°C. The offset (mm) of the test piece at this point was measured.

[0330] There is a tendency that the smaller the offset, the better the holding force (cohesion). Samples with an offset of less than 2.00 (mm) are evaluated as having good holding force (cohesion).

[0331] [Rating 3]

[0332] (Haze)

[0333] The optical resin sheet 2 obtained in the above-mentioned "Preparation of Optical Resin Sheet 2" was adhered to glass with a haze value of 0.1%, and then peeled off from the peeled polyethylene terephthalate film to prepare a test piece. Next, using a haze meter (HMG-2DP) manufactured by Suga Test Instruments, the haze of the test piece was measured on the side of the test piece with the peeled polyethylene terephthalate film facing the light source.

[0334] For samples with a haze value below 2.0%, the transparency was evaluated as good.

[0335] [Rating 4]

[0336] (Gel fraction)

[0337] The optical resin sheet 2 obtained in the above-mentioned "Preparation of optical resin sheet 2" was taken in a weight of 0.1g to 0.2g, wrapped in a #400 mesh sheet, impregnated in ethyl acetate for 1 week, and then dried at 120°C for 2 hours. The gel fraction (mass %) was then calculated using the following formula.

[0338] Samples with a gel fraction of 45.0% by mass or higher were evaluated as having good curing properties.

[0339] (Gel fraction)

[0340] = (Mass of sample after adding ethyl acetate and drying) / (Mass of sample before adding ethyl acetate) × 100

[0341] [Rating 5]

[0342] (Tensile test: elastic modulus, elongation, maximum stress and strain energy)

[0343] The optical resin sheet 1 obtained in the above-mentioned "Fabrication of Optical Resin Sheet 1" was peeled from the polyethylene terephthalate film after peeling treatment, and then stacked with a thickness of 200 μm. It was then cut into pieces with a width of 10 mm and a length of 40 mm. Subsequently, it was placed in a tensile testing machine with a clamping distance of 10 mm, and the elastic modulus, elongation, and maximum stress were measured at 300 mm / min in an environment of 23°C. Then, based on the obtained elongation and maximum stress, the strain energy index was calculated using the following formula.

[0344] Regarding Examples 1-1 to 1-14 and Comparative Examples 1-1 to 1-4, the elastic modulus was 0.40 N / mm². 2 Samples with a strain energy index of 1.70 or higher are evaluated as having good bending resistance.

[0345] Regarding Examples 2-1 to 2-20 and Comparative Examples 2-1 to 2-4, the elastic modulus (Young's modulus) was set to 0.40 N / mm². 2 The following samples with an elongation of 200% or more and a strain energy index of 1.50 or more are evaluated as having good bending resistance.

[0346] (Strain energy index) = {(Elongation (%) / 100) × (Maximum stress (MPa))} × 1 / 2

[0347] [Rating 6]

[0348] (Durability test)

[0349] The optical resin sheet 1 obtained in the above-mentioned "Preparation of optical resin sheet 1" was adhered to a 50mm×40mm glass plate, and air bubbles were completely removed. Then, it was placed in a 70℃ environmental testing chamber, and its peeling and other properties upon removal after 1000 hours were evaluated according to the following evaluation criteria.

[0350] (Evaluation Criteria)

[0351] ○: No peeling, floating, or bubbles can be observed.

[0352] △: Observe tiny bubbles at the tip, floating up.

[0353] ×: Obvious lifting and peeling of several millimeters or more was observed.

[0354] Synthesis of Acrylic Polymers (A1)

[0355] [Synthesis example 1-1-1]

[0356] (Synthesis of acrylic polymer A1-1)

[0357] 97 parts by mass of 2-ethylhexyl acrylate (2EHA) and 3 parts by mass of 4-hydroxybutyl acrylate (4HBA) were added to a four-necked flask equipped with a stirrer, thermometer, nitrogen inlet tube, and condenser, along with 140 parts by mass of ethyl acetate as a solvent. Then, while stirring under a nitrogen atmosphere, 0.15 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator were added, and the reaction was carried out at 61°C for 8 hours. After the reaction, the mixture was cooled to obtain an acrylic polymer A1-1 with a solid content of 42.0% by mass.

[0358] [Synthetic Examples 1-1-2 to 1-1-12 and 1-1-14 to 1-1-17]

[0359] (Synthesis of acrylic polymers A1-2 to A1-12 and A1-14 to A1-17)

[0360] Except that the mixing ratios of the monomers are set as shown in the table below, the acrylic polymers are synthesized using the same method as in Synthesis Example 1-1-1.

[0361] [Synthesis example 1-1-13]

[0362] (Synthesis of acrylic polymer A1-13)

[0363] 98.5 parts by mass of butyl acrylate (BA) and 1.5 parts by mass of 4-hydroxybutyl acrylate (4HBA) were added to a four-necked flask equipped with a stirrer, thermometer, nitrogen inlet tube, and condenser, along with 130 parts by mass of ethyl acetate as solvent. Then, while stirring under a nitrogen atmosphere, 0.15 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator were added, and the reaction was carried out at 60°C for 8 hours. After the reaction, the mixture was cooled to obtain an acrylic polymer A1-13 with a solid content of 43.5% by mass.

[0364] The composition and properties of the synthesized acrylic polymers are shown in the table below. It should be noted that in the table, the abbreviations of the monomers refer to the following compounds.

[0365] (Monomers containing cross-linking functional groups (a1))

[0366] 4HBA: 4-Hydroxybutyl acrylate

[0367] HEA: Hydroxyethyl acrylate

[0368] AA: Acrylic acid ((meth)acrylate monomer (a2)) 2EHA: 2-ethylhexyl acrylate MEA: Methoxyethyl acrylate iOA: Isooctyl acrylate

[0369] iNA: Isononyl acrylate

[0370] EA: Ethyl acrylate

[0371] MA: Methyl acrylate

[0372] BezA: Benzyl acrylate

[0373] BA: Butyl acrylate

[0374] PEA: Phenoxyethyl acrylate

[0375] CHA: Cyclohexyl acrylate (other polymerizable monomers (a3)) NVP: N-vinyl-2-pyrrolidone ACMO: Acryloylmorpholine

[0376] VAc: Vinyl acetate [Table 1-1]

[0377]

[0378] [Table 1-2]

[0379]

[0380] [Table 1-3]

[0381]

[0382] Synthesis of Crosslinking Agent Component (B1)

[0383] [Synthesis example 1-2-1]

[0384] (Synthesis of polyisocyanate component B1-a1)

[0385] Under a nitrogen atmosphere, 100 parts by weight of HDI were added to a four-necked flask equipped with a thermometer, stirring blades, and a reflux condenser. Simultaneously, 38.0 parts by weight of trifunctional polycaprolactone polyol (hereinafter sometimes referred to as "polyester polyol PO1-1") (manufactured by Daicel, trade name "PLACCEL 308", number average molecular weight 850, hydroxyl value 195.3 mg KOH / g) were added (the molar ratio of the isocyanate groups of HDI to the hydroxyl groups of polyester polyol PO1-1 was 9.0), while maintaining the temperature in the reactor at 85°C. The reaction was stopped when the yield reached 41.0% by weight. After filtering the reaction solution, unreacted HDI was removed using a thin-film distillation apparatus. Relative to 100 parts by mass of the obtained polyisocyanate, 1.0 parts by mass of polyester polyol PO1-1 and 2-ethylhexyl phosphate (JP-508T, manufactured by Chengbei Chemical Industry Co., Ltd.) were added to a four-necked flask equipped with a thermometer, stirring blade, and reflux condenser under a nitrogen gas flow.

[0386] 0.09 parts by mass were used to obtain polyisocyanate component B1-a1 by maintaining the temperature in the reactor at 90°C for 2 hours. Analysis of the obtained polyisocyanate component B1-a1 by ¹H NMR and C NMR confirmed the presence of urethane and urethane bonds, with urethane bonds having the highest molar ratio. The presence of isocyanurate bonds was not confirmed. Subsequently, ethyl acetate was added to the obtained polyisocyanate component, and the solution was diluted to 70% by mass (solid content) and remained liquid at 23°C.

[0387] [Synthesis example 1-2-2]

[0388] (Synthesis of polyisocyanate component B1-a2)

[0389] Under a nitrogen atmosphere, 100 parts by mass of HDI were added to a four-necked flask equipped with a thermometer, stirrer, and reflux condenser. While stirring, 40.0 parts by mass of polyester polyol PO1-1 (the molar ratio of the isocyanate groups of HDI to the hydroxyl groups of polyester polyol PO1-1 was 8.5) were added, and the temperature inside the reactor was maintained at 85°C. The reaction was stopped when the yield reached 41.5% by mass. After filtering the reaction solution, unreacted HDI was removed using a thin-film distillation apparatus. Relative to the 100 parts by mass of the obtained polyisocyanate, 1.0 parts by mass of polyester polyol PO1-1 and 0.09 parts by mass of 2-ethylhexyl phosphate (JP-508T, manufactured by Chengbei Chemical Industry Co., Ltd.) were added to a four-necked flask equipped with a thermometer, stirrer, and reflux condenser under a nitrogen atmosphere. The temperature inside the reactor was maintained at 90°C for 2 hours to obtain polyisocyanate component B1-a2. The obtained polyisocyanate component B1-a2 was analyzed by ¹H NMR and C NMR, confirming the presence of urethane and urethane bonds, with urethane bonds having the highest molar ratio. Isocyanurate bonds were not detected. Subsequently, ethyl acetate was added to the obtained polyisocyanate component, and the solution was diluted to 70% by mass (solid content) and remained liquid at 23°C.

[0390] [Synthesis example 1-2-3]

[0391] (Synthesis of polyisocyanate component B1-a3)

[0392] Under a nitrogen atmosphere, 100 parts by weight of HDI were added to a four-necked flask equipped with a thermometer, stirrer, and reflux condenser. While stirring, 40.0 parts by weight of a trifunctional polycaprolactone polyol (hereinafter sometimes referred to as "polyester polyol PO1-2") (manufactured by Daicel, trade name "PLACCEL 312", number average molecular weight 1250, hydroxyl value 136.1 mg KOH / g, acid value 0.38 mg KOH / g) were maintained in the reactor at 85°C. The reaction was stopped when the yield reached 39.5% by weight. The reaction solution was filtered, and unreacted HDI was removed using a thin-film distillation apparatus. Polyester polyol PO1-20 was added to a four-necked flask equipped with a thermometer, stirrer, and reflux condenser under a nitrogen atmosphere, relative to the obtained 100 parts by weight of polyisocyanate. Five parts by mass of 2-ethylhexyl phosphate (JP-508T, manufactured by Chengbei Chemical Industry Co., Ltd.) and 0.08 parts by mass of ethylhexyl phosphate were mixed, and the reactor temperature was maintained at 90°C for 2 hours to obtain polyisocyanate component B1-a3. Analysis of the obtained polyisocyanate component B1-a3 by ¹H NMR and C NMR confirmed the presence of urethane and urethane bonds, with urethane bonds having the highest molar ratio. The presence of isocyanurate bonds was not confirmed. Subsequently, ethyl acetate was added to the obtained polyisocyanate component, and the solution was diluted to 70% by mass of solids, becoming a liquid at 23°C.

[0393] [Synthesis example 1-2-4]

[0394] (Synthesis of polyisocyanate component B1-a4)

[0395] Under a nitrogen atmosphere, 100 parts by weight of HDI were added to a four-necked flask equipped with a thermometer, stirring blades, and a reflux condenser. Simultaneously, 60.0 parts by weight of a trifunctional polycaprolactone polyol (hereinafter sometimes referred to as "polyester polyol PO1-3") (manufactured by Daicel, trade name "PLACCEL 320", number average molecular weight 2000, hydroxyl value 85.4 mg KOH / g) were added (the molar ratio of the isocyanate groups of HDI to the hydroxyl groups of polyester polyol PO1-3 was 13.0), while maintaining the temperature in the reactor at 85°C. The reaction was stopped when the yield reached 43.5% by weight. Relative to 100 parts by mass of the obtained polyisocyanate, 1.0 parts by mass of polyester polyol PO1-3 and 0.08 parts by mass of 2-ethylhexyl phosphate (JP-508T, manufactured by Chengbei Chemical Industry Co., Ltd.) were added to a four-necked flask equipped with a thermometer, stirring blade, and reflux condenser under a nitrogen flow. The temperature inside the reactor was maintained at 90°C for 2 hours. After filtering the reaction solution, unreacted HDI was removed using a thin-film distillation apparatus to obtain polyisocyanate component B1-a4. Analysis of the obtained polyisocyanate component B1-a4 using ¹H NMR and C NMR confirmed the presence of urethane and urethane bonds, with urethane bonds having the highest molar ratio. The presence of isocyanurate bonds was not confirmed. Subsequently, ethyl acetate was added to the obtained polyisocyanate component, and the solution was diluted to a solid content of 70% by mass, becoming a liquid at 23°C.

[0396] [Synthesis example 1-2-5]

[0397] (Synthesis of polyisocyanate component B1-a5)

[0398] Under a nitrogen atmosphere, 100 parts by mass of HDI were added to a four-necked flask equipped with a thermometer, stirrer, and reflux condenser. While stirring, 39.0 parts by mass of polyester polyol PO1-1 (the molar ratio of HDI isocyanate groups to hydroxyl groups of polyester polyol PO1-1 was 8.8) were added, and the temperature in the reactor was maintained at 85°C. The reaction was stopped when the yield reached 41.5% by mass. The reaction solution was filtered, and unreacted HDI was removed using a thin-film distillation apparatus. Relative to the obtained 100 parts by mass of isocyanate, under a nitrogen atmosphere, 1.0 parts by mass of polyester polyol PO1-1, 0.5 parts by mass of polyethylene glycol monomethyl ether (MPG081, repeating unit n=15), and 2-ethylhexyl phosphate (JP-508T, manufactured by Chengbei Chemical Industry Co., Ltd.) were added to the four-necked flask equipped with a thermometer, stirrer, and reflux condenser.

[0399] 0.08 parts by mass were used to obtain polyisocyanate component B1-a5 by maintaining the temperature in the reactor at 90°C for 2 hours. Analysis of the obtained polyisocyanate component B1-a5 using ¹H NMR and C NMR confirmed the presence of urethane and urethane bonds, with urethane bonds having the highest molar ratio. The presence of isocyanurate bonds was not confirmed. Subsequently, ethyl acetate was added to the obtained polyisocyanate component, and the solution was diluted to 70% by mass (solid content) and remained liquid at 23°C.

[0400] [Synthesis example 1-2-6]

[0401] (Synthesis of polyisocyanate component B1-b1)

[0402] Under a nitrogen gas flow, 100 parts by mass of HDI and 8.8 parts by mass of trimethylolpropane (TMP) were added to a four-necked flask equipped with a thermometer, stirring blades, and a reflux condenser. The temperature inside the reactor was maintained at 75°C for 5.5 hours with stirring to carry out the carbamate reaction. After filtering the reaction solution, unreacted HDI was removed using a thin-film evaporator to obtain polyisocyanate (hereinafter sometimes referred to as "polyisocyanate component B1-b1"). The obtained polyisocyanate component B1-b1 had an NCO content of 17.4% by mass and a weight-average molecular weight of 1.06 × 10⁻⁶. 3 The obtained polyisocyanate components B1-b1 were analyzed by ¹H NMR and C NMR, confirming the presence of urethane and urethane bonds, with the urethane bond having the highest molar ratio. No isocyanurate bonds were detected. Subsequently, ethyl acetate was added to the obtained polyisocyanate components, and the mixture was diluted to a solid content of 70% by mass, becoming a liquid at 23°C.

[0403] [Synthesis example 1-2-7]

[0404] (Synthesis of polyisocyanate components B1-b2)

[0405] Under a nitrogen gas flow, 100 parts by mass of HDI were added to a four-necked flask equipped with a thermometer, stirring blades, and a reflux condenser. The reactor temperature was maintained at 61°C with stirring. 0.095 parts by mass of trimethylbenzylammonium hydroxide were added. After 3.5 hours, when the conversion reached 36% by mass, 0.02 parts by mass of phosphoric acid were added, and the reaction was stopped. The reaction solution was filtered, and unreacted HDI was removed using a thin-film evaporator to obtain isocyanurate-type polyisocyanates (hereinafter sometimes referred to as "polyisocyanate component B1-b2"). The obtained polyisocyanate component B1-b2 had an NCO content of 23.2% by mass and a weight-average molecular weight of 7.3 × 10⁻⁶. 2The average number of isocyanate groups was 3.2. The presence of isocyanurate groups was confirmed by NMR determination.

[0406] [Synthesis example 1-2-8]

[0407] (Synthesis of polyisocyanate components B1-b3)

[0408] Under a nitrogen atmosphere, 100 parts by mass of HDI were added to a four-necked flask equipped with a thermometer, stirring blades, and a reflux condenser. Simultaneously, 22.0 parts by mass of a trifunctional polycaprolactone polyol (hereinafter sometimes referred to as "polyester polyol PO1-4") (manufactured by Daicel, trade name "PLACCEL 305", number average molecular weight 550) (the molar ratio of HDI isocyanate groups to polyol hydroxyl groups being 9.9) were added, while maintaining the reactor temperature at 85°C for 80 minutes. The reaction was stopped when the yield reached 35% by mass. After filtering the reaction solution, unreacted HDI was removed using a thin-film distillation apparatus to obtain polyisocyanate component B1-b3. Analysis of the obtained polyisocyanate component B1-b3 using ¹H NMR and C NMR confirmed the presence of urethane and urea bonds, with urethane bonds having the highest molar ratio among these bonds. Subsequently, ethyl acetate was added to the obtained polyisocyanate component, and the mixture was diluted to a solid content of 70% by mass at 23°C to form a liquid.

[0409] [Synthesis example 1-2-9]

[0410] (Synthesis of polyisocyanate component B1-a6)

[0411] Under a nitrogen atmosphere, 100 parts by mass of HDI were added to a four-necked flask equipped with a thermometer, stirrer, and reflux condenser. While stirring, 35.0 parts by mass of polyester polyol PO-1 (the molar ratio of the isocyanate groups of HDI to the hydroxyl groups of polyester polyol PO1-1 was 9.8) were added, and the temperature inside the reactor was maintained at 85°C. The reaction was stopped when the yield reached 40.5% by mass. After filtering the reaction solution, unreacted HDI was removed using a thin-film distillation apparatus. Relative to the 100 parts by mass of the obtained polyisocyanate, 3.0 parts by mass of polyester polyol PO1-1 and 0.09 parts by mass of 2-ethylhexyl phosphate (JP-508T, manufactured by Chengbei Chemical Industry Co., Ltd.) were added to a four-necked flask equipped with a thermometer, stirrer, and reflux condenser. The temperature inside the reactor was maintained at 90°C for 2 hours to obtain polyisocyanate component B1-a6. The obtained polyisocyanate component B1-a6 was analyzed by ¹H NMR and C NMR, confirming the presence of urethane and urethane bonds, with the urethane bond having the highest molar ratio. The presence of isocyanurate bonds was not confirmed. Subsequently, ethyl acetate was added to the obtained polyisocyanate component, and the solution was diluted to 70% by mass (solid content) and remained liquid at 23°C.

[0412] [Synthesis example 1-2-10]

[0413] (Synthesis of polyisocyanate component B1-a7)

[0414] Under a nitrogen atmosphere, 100 parts by mass of HDI were added to a four-necked flask equipped with a thermometer, stirrer, and reflux condenser. While stirring, 37.0 parts by mass of polyester polyol PO-1 (the molar ratio of the isocyanate groups of HDI to the hydroxyl groups of polyester polyol PO1-1 was 9.2) were added, and the temperature inside the reactor was maintained at 85°C. The reaction was stopped when the yield reached 41.0% by mass. After filtering the reaction solution, unreacted HDI was removed using a thin-film distillation apparatus. Relative to the 100 parts by mass of the obtained polyisocyanate, 4.0 parts by mass of polyester polyol PO1-1 and 0.09 parts by mass of 2-ethylhexyl phosphate (JP-508T, manufactured by Chengbei Chemical Industry Co., Ltd.) were added to a four-necked flask equipped with a thermometer, stirrer, and reflux condenser. The temperature inside the reactor was maintained at 90°C for 2 hours to obtain polyisocyanate component B1-a7. The obtained polyisocyanate component B1-a7 was analyzed by ¹H NMR and C NMR, confirming the presence of urethane and urethane bonds, with the urethane bond having the highest molar ratio. The presence of isocyanurate bonds was not confirmed. Subsequently, ethyl acetate was added to the obtained polyisocyanate component, and the solution was diluted to 70% by mass (solid content) and remained liquid at 23°C.

[0415] [Synthesis example 1-2-11]

[0416] (Synthesis of polyisocyanate component B1-a8)

[0417] The interior of a four-necked flask equipped with a stirrer, thermometer, and condenser was purged with nitrogen. 1000 g of HDI was added, and 0.1 g of tetramethyldecanoate ammonium was added as a catalyst at 65°C with stirring. After 3.5 hours, the predetermined reaction endpoint was confirmed by measuring the refractive index of the reaction solution, and 0.2 g of phosphoric acid was added to stop the reaction. The reaction solution was then filtered, and unreacted HDI monomers were removed using a thin-film distillation apparatus, yielding polyisocyanate B1-a8 with an isocyanurate structure. The obtained polyisocyanate B1-a8 had an isocyanate group content of 23.4% by mass, an average number of isocyanate functional groups of 3.27, and a weight-average molecular weight of 755.

[0418] [Synthesis example 1-2-12]

[0419] (Synthesis of polyisocyanate component B1-a9)

[0420] The interior of a four-necked flask equipped with a stirrer, thermometer, and condenser was purged with nitrogen. 1000 g of HDI, 8.5 g of water, and 600 g of methyl cellosolve acetate were mixed at room temperature and reacted at 135°C under normal pressure for 110 minutes. Subsequently, the reaction was carried out at 157°C for 1 hour. No precipitate or turbidity was observed. The reaction solution was then filtered, and unreacted HDI monomer and solvent were removed using a thin-film distillation apparatus to obtain a polyisocyanate. The obtained polyisocyanate had an isocyanate group content of 23.5% by mass, an average number of isocyanate functional groups of 3.34, and a weight-average molecular weight of 860. Analysis of the obtained polyisocyanate composition B1-a9 using ¹H NMR and C₂NMR confirmed the presence of biuret groups.

[0421] The composition and properties of the synthesized polyisocyanates are shown in the table below. It should be noted that the polyols in the table are the following compounds.

[0422] (Trifunctional polyols)

[0423] PO1-1: Trifunctional polycaprolactone polyol, manufactured by Daicel, trade name "PLACCEL308", number average molecular weight 850.

[0424] PO1-2: Trifunctional polycaprolactone polyol, manufactured by Daicel, trade name "PLACCEL312", number average molecular weight 1250

[0425] PO1-3: Trifunctional polycaprolactone polyol, manufactured by Daicel, trade name "PLACCEL320", number average molecular weight 2000

[0426] PO1-4: Trifunctional polycaprolactone polyol, manufactured by Daicel, trade name "PLACCEL305", number average molecular weight 550

[0427] (Other polyols)

[0428] TMP: Trimethylolpropane

[0429] [Table 1-4]

[0430]

[0431] [Table 1-5]

[0432]

[0433] [Mixing Example 1-1]

[0434] (The blending of polyisocyanate components B1-c1)

[0435] Polyisocyanate B1-a6 containing urethane bonds and polyisocyanate B1-a8 having isocyanurate structure were mixed at a solid content ratio of 97% by mass: 3% by mass to obtain polyisocyanate component B1-c1.

[0436] [Formulation Examples 1-2]

[0437] (The blending of polyisocyanate components B1-c2)

[0438] Polyisocyanate B1-a6 containing urethane bonds and polyisocyanate composition B1-a9 having a biuret structure were mixed at a solid content ratio of 97% by mass: 3% by mass to obtain polyisocyanate composition B1-c2.

[0439] <Preparation of Resin Compositions for Optical Applications>

[0440] [Example 1-1]

[0441] (Preparation of optical resin composition O1-a1)

[0442] Optical resin composition O1-a1 was prepared by adding 0.7 parts by mass of polyisocyanate component B1-1 and 0.12 parts by mass of silane coupling agent (KBM-403) to 100 parts by mass of acrylic polymer A1-1, and using ethyl acetate as the solid component at 30% by mass.

[0443] [Examples 1-2 to 1-22 and Comparative Examples 1-1 to 1-4]

[0444] (Preparation of optical resin compositions O1-a2~O1-a22 and O1-b1~O1-b4)

[0445] Except that the types and mixing ratios of the acrylic polymer (A1) and the crosslinking agent component (B1) are set as described in the table below, the various optical resin compositions are manufactured using the same method as in Examples 1-1.

[0446] The composition and evaluation results of each optical resin composition are shown in the table below.

[0447] [Table 1-6]

[0448]

[0449] [Table 1-7]

[0450]

[0451] [Table 1-8]

[0452]

[0453] [Table 1-9]

[0454]

[0455] [Table 1-10]

[0456]

[0457] According to Tables 1-6 to 1-10, the optical resin sheets obtained using optical resin compositions O1-a1 to O1-a22 (Examples 1-1 to 1-22) containing acrylic polymers (A1) with glass transition temperatures within a specific range and crosslinking agent components (B1) with weight-average molecular weight and average number of isocyanate groups within a specific range have good transparency and excellent adhesion, holding power, flexural strength and durability.

[0458] On the other hand, optical resin sheets obtained by using optical resin compositions O1-b1 to O1-b4 (Comparative Examples 1-1 to 1-4) containing an acrylic polymer (A1) with a glass transition temperature within a specific range and a crosslinking agent component (B1) with a weight-average molecular weight of less than 2100 and an average number of isocyanate groups of less than 3.5 do not achieve excellent results in all aspects of transparency, adhesion, holding power, bending resistance and durability.

[0459] Synthesis of Acrylic Polymer (A2)

[0460] [Synthesis example 2-1-1]

[0461] (Synthesis of acrylic polymer A2-1)

[0462] 97 parts by mass of 2-ethylhexyl acrylate (2EHA) and 3 parts by mass of 4-hydroxybutyl acrylate (4-HBA) were added to a four-necked flask equipped with a stirrer, thermometer, nitrogen inlet tube, and condenser, along with 130 parts by mass of ethyl acetate as solvent. Then, while stirring under a nitrogen atmosphere, 0.15 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator were added, and the reaction was carried out at 63°C for 8 hours. After cooling, an acrylic polymer A2-1 with a solid content of 43.5% by mass was obtained. The weight-average molecular weight (Mw) of acrylic polymer A2-1, measured after removing the solvent, was 990,000.

[0463] [Synthesis Example 2-1-2~2-1-12]

[0464] (Synthesis of acrylic polymers A2-2 to A2-12)

[0465] Except that the mixing ratios of the monomers are set as shown in the table below, the acrylic polymers are synthesized using the same method as in Synthesis Example 2-1-1.

[0466] [Synthesis example 2-1-13]

[0467] (Synthesis of acrylic polymer A2-13)

[0468] 98.5 parts by mass of butyl acrylate (BA) and 1.5 parts by mass of 4-hydroxybutyl acrylate (4HBA) were added to a four-necked flask equipped with a stirrer, thermometer, nitrogen inlet tube, and condenser, along with 130 parts by mass of ethyl acetate as solvent. Then, while stirring under a nitrogen atmosphere, 0.15 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator were added, and the reaction was carried out at 62°C for 8 hours. After cooling, an acrylic polymer A2-13 with a solid content of 43.5% by mass was obtained. The weight-average molecular weight (Mw) of acrylic polymer A2-13, after removing the solvent, was 1.17 million.

[0469] The composition and properties of the synthesized acrylic polymers are shown in the table below. It should be noted that in the table, the abbreviations of the monomers refer to the following compounds.

[0470] (Monomers containing cross-linking functional groups (a1))

[0471] 4HBA: 4-Hydroxybutyl acrylate

[0472] HEA: Hydroxyethyl acrylate

[0473] AA: Acrylic acid ((meth)acrylate monomer (a2)) 2EHA: 2-ethylhexyl acrylate MEA: Methoxyethyl acrylate iOA: Isooctyl acrylate

[0474] iNA: Isononyl acrylate

[0475] EA: Ethyl acrylate

[0476] MA: Methyl acrylate

[0477] BezA: Benzyl acrylate

[0478] BA: Butyl acrylate (other polymerizable monomers (a3)) NVP: N-vinyl-2-pyrrolidone [Table 2-1]

[0479]

[0480] [Table 2-2]

[0481]

[0482] Synthesis of Crosslinking Agent Component (B2)

[0483] [Synthesis example 2-2-1]

[0484] (Synthesis of polyisocyanate component B2-a1)

[0485] Under a nitrogen gas flow, 100 parts by mass of HDI and 3.95 parts by mass of 2-ethylhexanol (the molar ratio of HDI isocyanate groups to hydroxyl groups in 2-ethylhexanol is 10) were added to a four-necked flask equipped with a thermometer, stirring blades, and a reflux condenser. The mixture was reacted at 100°C for 45 minutes. The temperature was then raised to 130°C, and 70 ppm of 2-ethylhexanoic acid / zirconia was added relative to the total mass of the reaction solution. The mixture was stirred for another 2 hours. Subsequently, the temperature was lowered to 100°C, and 125 parts by mass of a difunctional polycaprolactone polyol (hereinafter sometimes referred to as "polyester polyol PO2-1") (manufactured by Daicel, trade name "PLACCEL 220CPT", number average molecular weight 2000, hydroxyl value 56.6 mg KOH / g) (the molar ratio of HDI isocyanate groups to hydroxyl groups in polyester polyol PO2-1 is 9.4) were stirred while maintaining the reactor temperature at 100°C. At a yield of 57.0% by mass, 0.02 parts by mass of phosphoric acid were added to stop the reaction. The reaction solution was filtered, and unreacted HDI was removed using a thin-film distillation apparatus to obtain the polyisocyanate component B2-a1. Analysis of the obtained polyisocyanate component B2-a1 by ¹H NMR and C NMR confirmed the presence of urethane, urea, and urea groups, but no isocyanurate groups were identified. Among these functional groups, the urethane group had the highest molar ratio. Subsequently, ethyl acetate was added to the obtained polyisocyanate component B2-a1, and the solution was diluted to a solid content of 70% by mass, becoming a liquid at 23°C.

[0486] It should be noted that, in the following NMR-based functional group detection of crosslinking agent component (B2), the presence of a functional group is defined as the presence of the respective functional groups of urea carbamate group, urea diketone group, iminooxadiazine diketone group, isocyanurate group, urea group, carbamate group and biuret group relative to the total detected molar amount in a proportion (mol%) of 1 mol% or more.

[0487] [Synthesis example 2-2-2]

[0488] (Synthesis of polyisocyanate component B2-a2)

[0489] Under a nitrogen atmosphere, 100 parts by mass of HDI were added to a four-necked flask equipped with a thermometer, stirring blades, and a reflux condenser. While stirring, 120 parts by mass of polyester polyol PO2-1 (the molar ratio of HDI isocyanate groups to hydroxyl groups of polyester polyol PO2-1 was 9.8) were added. The reaction was carried out at 100°C for 1.5 hours, then the temperature was raised to 130°C. 70 ppm of 2-ethylhexanoic acid / zirconia was added relative to the total mass of the reaction solution, and the mixture was stirred at 130°C for 40 minutes. Subsequently, 0.02 parts by mass of phosphoric acid were added at a yield of 56.0% by mass to stop the reaction. The reaction solution was filtered, and unreacted HDI was removed using a thin-film distillation apparatus to obtain the polyisocyanate component B2-a2. Analysis of the obtained polyisocyanate component B2-a2 using ¹H NMR and C NMR confirmed the presence of urethane and urea groups, but no isocyanurate groups were identified. Among these functional groups, the urethane group has the highest molar ratio. Subsequently, ethyl acetate was added to the obtained polyisocyanate component B2-a2, and the mixture was diluted to a solid content of 70% by mass at 23°C to form a liquid.

[0490] [Synthesis example 2-2-3]

[0491] (Synthesis of polyisocyanate component B2-a3)

[0492] Under a nitrogen atmosphere, 100 parts by mass of HDI were added to a four-necked flask equipped with a thermometer, stirring blades, and a reflux condenser. While stirring, 135 parts by mass of polyester polyol PO2-1 (the molar ratio of HDI isocyanate groups to hydroxyl groups of polyester polyol PO2-1 was 8.7) were added. The reaction was carried out at 100°C for 1.5 hours, then the temperature was raised to 130°C. 70 ppm of 2-ethylhexanoic acid / zirconia was added relative to the total mass of the reaction solution, and the mixture was stirred at 130°C for 40 minutes. Subsequently, 0.02 parts by mass of phosphoric acid were added at a yield of 58.0% by mass to stop the reaction. The reaction solution was filtered, and unreacted HDI was removed using a thin-film distillation apparatus to obtain polyisocyanate component B2-a3. Analysis of the obtained polyisocyanate component B2-a3 using ¹H NMR and C NMR confirmed the presence of carbamate and urea carbamate groups, but no isocyanurate groups were identified. Among these functional groups, the urethane group has the highest molar ratio. Subsequently, ethyl acetate was added to the obtained polyisocyanate component B2-a3, and the mixture was diluted to a solid content of 70% by mass at 23°C to form a liquid.

[0493] [Synthesis example 2-2-4]

[0494] (Synthesis of polyisocyanate component B2-a4)

[0495] Under a nitrogen gas flow, 100 parts by mass of HDI were added to a four-necked flask equipped with a thermometer, stirring blades, and a reflux condenser. While stirring, 1.0 part by mass of 1,3-butanediol and 125 parts by mass of polyester polyol PO2-1 (the molar ratio of isocyanate groups of HDI to hydroxyl groups of polyester polyol PO2-1 was 9.4) were added. The temperature in the reactor was maintained at 160°C for 30 minutes, then lowered to 100°C and maintained thereafter. The reaction was stopped when the yield reached 57.0% by mass. After filtering the reaction solution, unreacted HDI was removed using a thin-film distillation apparatus to obtain the polyisocyanate component B2-a4. Analysis of the obtained polyisocyanate component B2-a4 using ¹H NMR and C NMR confirmed the presence of urethane, urea-formate, urea-diketone, and urea groups, but no isocyanurate groups were identified. Among these functional groups, the urethane group had the highest molar ratio. Subsequently, ethyl acetate was added to the obtained polyisocyanate component B2-a4, and the mixture was diluted to a solid content of 70% by mass at 23°C to form a liquid.

[0496] [Synthesis example 2-2-5]

[0497] (Synthesis of polyisocyanate component B2-a5)

[0498] Under a nitrogen atmosphere, 100 parts by mass of HDI were added to a four-necked flask equipped with a thermometer, stirring blades, and a reflux condenser. Simultaneously, 145 parts by mass of difunctional polycaprolactone diol (hereinafter sometimes referred to as "polyester polyol PO2-2") (manufactured by Daicel, trade name "PLACCEL 230", number average molecular weight 3000) were added (the molar ratio of the isocyanate groups of HDI to the hydroxyl groups of polyester polyol PO2-2 was 12.2). The reaction was carried out at 100°C for 1.5 hours, then the temperature was raised to 130°C. 70 ppm by mass of 2-ethylhexanoic acid / zirconia was added relative to the total mass of the reaction solution, and the mixture was stirred at 130°C for 40 minutes. The reaction was then stopped when the yield reached 57.5% by mass. The reaction solution was filtered, and unreacted HDI was removed using a thin-film distillation apparatus to obtain the polyisocyanate component B2-a5. The obtained polyisocyanate component B2-a5 was analyzed by ¹H NMR and C NMR, confirming the presence of urethane and urea formate groups, but not isocyanurate groups. Among these functional groups, the urethane group had the highest molar ratio. Subsequently, ethyl acetate was added to the obtained polyisocyanate component B2-a5, and the mixture was diluted to a solid state at 23°C to a solid content of 70% by mass.

[0499] [Synthesis example 2-2-6]

[0500] (Synthesis of polyisocyanate component B2-a6)

[0501] Under a nitrogen gas flow, 100 parts by mass of HDI, 2.0 parts by mass of 1,3-butanediol, and 135 parts by mass of polyester polyol PO2-1 (with a molar ratio of HDI isocyanate groups to hydroxyl groups of polyester polyol PO2-1 of 8.7) were added to a four-necked flask equipped with a thermometer, stirring blades, and a reflux condenser while stirring. The mixture was reacted at 160°C for 40 minutes. After filtration, unreacted HDI was removed using a thin-film distillation apparatus. 2 parts by mass of polyester polyol PO2-1 and 0.090 parts by mass of 2-ethylhexyl phosphate (manufactured by Chengbei Chemical Industry Co., Ltd., trade name "JP508T") were added to 100 parts by mass of the obtained polyisocyanate precursor. The temperature in the reactor was maintained at 90°C for 150 minutes to obtain polyisocyanate component B2-a6. The obtained polyisocyanate component B2-a6 was analyzed by ¹H NMR and C NMR, confirming the presence of urethane, urea-formate, urea-diketone, and urea groups, but not isocyanurate groups. Among these functional groups, the urethane group had the highest molar ratio. Subsequently, ethyl acetate was added to the obtained polyisocyanate component B2-a6, and the mixture was diluted to a solid content of 70% by mass, becoming a liquid at 23°C.

[0502] [Synthesis example 2-2-7]

[0503] (Synthesis of polyisocyanate component B2-a7)

[0504] Under a nitrogen gas flow, 100 parts by mass of HDI, 1.5 parts by mass of 1,3-butanediol, and 130 parts by mass of polyester polyol PO2-1 (with a molar ratio of HDI isocyanate groups to hydroxyl groups of polyester polyol PO2-1 of 9.1) were added to a four-necked flask equipped with a thermometer, stirring blades, and a reflux condenser. The mixture was reacted at 160°C for 40 minutes. After filtration, unreacted HDI was removed using a thin-film distillation apparatus. Relative to 100 parts by mass of the obtained polyisocyanate precursor, 2 parts by mass of polyester polyol PO2-1 and 2 parts by mass of methyl polyalkylene glycol (repeating unit n=15) were added while stirring, along with 0.09 parts by mass of JP508T relative to the resin composition. The temperature inside the reactor was maintained at 90°C for 150 minutes to obtain polyisocyanate component B2-a7. The obtained polyisocyanate component B2-a7 was analyzed by ¹H NMR and C NMR, confirming the presence of urethane, urea-formate, urea-diketone, and urea groups, but not isocyanurate groups. Among these functional groups, the urethane group had the highest molar ratio. Subsequently, ethyl acetate was added to the obtained polyisocyanate component B2-a7, and the mixture was diluted to a solid content of 70% by mass, becoming a liquid at 23°C.

[0505] [Synthesis example 2-2-8]

[0506] (Synthesis of polyisocyanate component B2-a8)

[0507] Under a nitrogen gas flow, 100 parts by mass of HDI, 2.5 parts by mass of 1,3-butanediol, and 90 parts by mass of polyester polyol PO2-1 (the molar ratio of the isocyanate groups of HDI to the hydroxyl groups of polyester polyol PO2-1 was 13.1) were added to a four-necked flask equipped with a thermometer, stirring blades, and a reflux condenser while stirring. The mixture was reacted at 160°C for 40 minutes. After filtration, unreacted HDI was removed using a thin-film distillation apparatus. 1 part by mass of polyester polyol PO2-1 and 0.09 parts by mass of 2-ethylhexyl phosphate (manufactured by Chengbei Chemical Industry Co., Ltd., trade name "JP508T") were added relative to 100 parts by mass of the obtained polyisocyanate precursor. The temperature in the reactor was maintained at 90°C for 150 minutes to obtain polyisocyanate component B2-a8. The obtained polyisocyanate component B2-a8 was analyzed by ¹H NMR and C NMR, confirming the presence of urethane, urea-formate, urea-diketone, and urea groups, but not isocyanurate groups. Among these functional groups, the urethane group had the highest molar ratio. Subsequently, ethyl acetate was added to the obtained polyisocyanate component B2-a8, and the mixture was diluted to a solid content of 70% by mass, becoming a liquid at 23°C.

[0508] [Synthesis example 2-2-9]

[0509] (Synthesis of polyisocyanate component B2-a9)

[0510] Under a nitrogen atmosphere, 100 parts by mass of HDI were added to a four-necked flask equipped with a thermometer, stirring blades, and a reflux condenser. After reacting 0.5 parts by mass of isobutanol at 100°C for 45 minutes, the temperature was raised to 130°C. Then, 70 ppm of 2-ethylhexanoic acid / zirconia (based on the total mass of the reaction solution) was added, and the temperature was raised to 130°C again, with stirring continued for 1 hour. Subsequently, the temperature was lowered to 100°C, and 190 parts by mass of polycaprolactone polyol (hereinafter sometimes referred to as "polyester polyol PO2-3") (manufactured by Daicel, trade name "PLACCEL 240", number average molecular weight 4000) were stirred while maintaining the reactor temperature at 100°C (the molar ratio of the isocyanate groups of HDI to the hydroxyl groups of polyester polyol PO2-3 was 12.3). At a yield of 62.0% by mass, 0.02 parts by mass of phosphoric acid were added, and the reaction was stopped. After filtering the reaction solution, unreacted HDI was removed using a thin-film distillation apparatus to obtain the polyisocyanate component B2-a9. Analysis of the obtained polyisocyanate component B2-a9 using ¹H NMR and C NMR confirmed the presence of urethane, urea, and urea groups, but no isocyanurate groups were identified. Among these functional groups, the urethane group had the highest molar ratio. Subsequently, ethyl acetate was added to the obtained polyisocyanate component B2-a9 to dilute it to a solid state of 70% by mass at 23°C.

[0511] [Synthesis example 2-2-10]

[0512] (Synthesis of polyisocyanate components B2-b1)

[0513] Under a nitrogen gas flow, 100 parts by mass of HDI and 8.85 parts by mass of trimethylolpropane (the molar ratio of the isocyanate groups of HDI to the hydroxyl groups of trimethylolpropane was 6.0) were added to a four-necked flask equipped with a thermometer, stirring blades, and a reflux condenser. The temperature inside the reactor was maintained at 75°C for 6.5 hours with stirring to carry out the carbamate reaction. After filtering the reaction solution, unreacted HDI was removed using a thin-film evaporator to obtain polyisocyanate (hereinafter sometimes referred to as "polyisocyanate component B2-b1"). The obtained polyisocyanate component B2-b1 had an NCO content of 17.3% by mass and a weight-average molecular weight of 1.13 × 10⁻⁶. 3 The average number of isocyanate groups is 3.3. Carbamate groups were identified as the main component by NMR analysis. Isocyanurate groups were not identified.

[0514] [Synthesis example 2-2-11]

[0515] (Synthesis of polyisocyanate component B2-b2)

[0516] Under a nitrogen gas flow, 100 parts by mass of HDI were added to a four-necked flask equipped with a thermometer, stirring blades, and a reflux condenser. The temperature inside the reactor was maintained at 62°C with stirring. 0.095 parts by mass of trimethylbenzylammonium hydroxide were added. After 3.8 hours, when the conversion reached 35% by mass, 0.02 parts by mass of phosphoric acid were added, and the reaction was stopped. The reaction solution was filtered, and unreacted HDI was removed using a thin-film evaporator to obtain isocyanurate-type polyisocyanate (hereinafter sometimes referred to as "polyisocyanate component B2-b2"). The obtained polyisocyanate component B2-b2 had an NCO content of 23.2% by mass and a weight-average molecular weight of 7.38 × 10⁻⁶. 2 The average number of isocyanate groups was 3.2. The presence of isocyanurate groups was confirmed by NMR determination, confirming that isocyanurate groups are the main component.

[0517] [Synthesis example 2-2-12]

[0518] (Synthesis of polyisocyanate components B2-b3)

[0519] Under a nitrogen atmosphere, 100 parts by mass of HDI were added to a four-necked flask equipped with a thermometer, stirring blades, and a reflux condenser. Simultaneously, 22 parts by mass of a trifunctional polycaprolactone polyol (hereinafter sometimes referred to as "polyester polyol PO2'-1") (manufactured by Daicel, trade name "PLACCEL 305", number average molecular weight 550) were stirred (the molar ratio of the isocyanate groups of HDI to the hydroxyl groups of polyester polyol PO2'-1 was 9.9). The temperature inside the reactor was maintained at 93°C for 100 minutes. The reaction was stopped when the yield reached 36% by mass. After filtering the reaction solution, unreacted HDI was removed using a thin-film distillation apparatus to obtain the polyisocyanate component B2-b3. The obtained polyisocyanate component B2-b3 had an NCO content of 10.1% by mass and a weight average molecular weight of 2.04 × 10⁻⁶. 3 The average isocyanate group number is 3.4.

[0520] The composition and properties of the synthesized polyisocyanates are shown in the table below. It should be noted that the polyols in the table are the following compounds.

[0521] (Difunctional polyols)

[0522] PO2-1: A difunctional polycaprolactone polyol, manufactured by Daicel, trade name "PLACCEL220CPT", with a number average molecular weight of 2000.

[0523] PO2-2: A difunctional polycaprolactone polyol, manufactured by Daicel, trade name "PLACCEL230", with a number average molecular weight of 3000.

[0524] PO2-3: A difunctional polycaprolactone polyol, manufactured by Daicel, trade name "PLACCEL240", with a number average molecular weight of 4000.

[0525] (Other polyols)

[0526] TMP: Trimethylolpropane

[0527] PO2'-1: A trifunctional polycaprolactone polyol, manufactured by Daicel, trade name "PLACCEL305", with a number average molecular weight of 550.

[0528] [Table 2-3]

[0529]

[0530] [Table 2-4]

[0531]

[0532] <Preparation of Resin Compositions for Optical Applications>

[0533] [Example 2-1]

[0534] (Preparation of optical resin composition O2-a1)

[0535] Optical resin composition O2-a1 was prepared by adding 0.85 parts by mass of polyisocyanate component B2-1 and 0.10 parts by mass of silane coupling agent (KBM-403) to 100 parts by mass of acrylic polymer A2-1, and using ethyl acetate as the solid component at 30% by mass.

[0536] [Examples 2-2 to 2-20 and Comparative Examples 2-1 to 2-4]

[0537] (Preparation of optical resin compositions O2-a2~O2-a20 and O2-b1~O2-b4)

[0538] Except that the types and mixing ratios of the acrylic polymer (A2) and crosslinking agent (B2) are set as described in the table below, the various optical resin compositions are manufactured using the same method as in Examples 2-1.

[0539] The composition and evaluation results of each optical resin composition are shown in the table below.

[0540] [Table 2-5]

[0541]

[0542] [Table 2-6]

[0543]

[0544] [Table 2-7]

[0545]

[0546] [Table 2-8]

[0547]

[0548] According to the table above, the optical resin sheets obtained using optical resin compositions O2-a1 to O2-a20 (Examples 2-1 to 2-20) containing an acrylic polymer (A2) with a glass transition temperature within a specific range, and a polyisocyanate (b1) derived from a polyol (b2) selected from aliphatic diisocyanates and alicyclic diisocyanates with a number average molecular weight of 1100 or more and an average number of hydroxyl groups of 1.5 or more and 2.5 or less, and having a molar ratio of the isocyanate group of the diisocyanate (b1) to the total molar ratio of the hydroxyl groups of the polyol (b2) NCO / OH and a crosslinking agent component (B2) with a weight average molecular weight within a specific range, exhibit good transparency and excellent adhesion, holding power, and flexural strength.

[0549] On the other hand, optical resin sheets obtained by using optical resin compositions O2-b1 to O2-b4 (Comparative Examples 2-1 to 2-4) containing an acrylic polymer (A2) with a glass transition temperature within a specific range and a crosslinking agent component (B2) with a weight average molecular weight of less than 2100 do not achieve excellent results in all aspects of transparency, adhesion, holding power and bending resistance.

[0550] Industrial availability

[0551] The optical resin composition according to this embodiment provides an optical resin composition that not only maintains good transparency when manufactured into an optical resin sheet, but also exhibits excellent adhesion, holding power, flexural strength, and durability. The optical resin sheet of this embodiment is formed by curing the aforementioned optical resin composition, and has good transparency, as well as excellent adhesion, holding power, flexural strength, and durability.

Claims

1. An optical resin composition comprising a polymer (A) and a crosslinking agent (B), wherein the polymer (A) is one or more selected from the group consisting of acrylic polymers, urethane polymers, and rubber polymers. The polymer (A) has a glass transition temperature (Tg) above -110.0℃ and below -10.0℃. The crosslinking agent component (B) comprises an aliphatic polyisocyanate with a weight-average molecular weight of 2100 or more and 200000 or less, and an average number of isocyanate groups of 3.5 or more and 6.5 or less. The polymer (A) comprises structural units derived from monomers containing crosslinking functional groups, wherein the crosslinking functional groups include one or more selected from the group consisting of hydroxyl, thiol, amino, amide, epoxy, and carboxyl groups. The content of the structural units derived from monomers containing crosslinking functional groups is 0.01% by mass and less than 30% by mass relative to the total mass of the polymer (A). The content of crosslinking agent component (B) relative to 100 parts by weight of polymer (A) is more than 0.05 parts by weight and less than 80.0 parts by weight. The aliphatic polyisocyanate is a polyisocyanate derived from at least one diisocyanate (b1) selected from aliphatic diisocyanates and a polyol (b2) with a number average molecular weight exceeding 550, wherein the polyol (b2) is a trifunctional polycaprolactone polyol.

2. The optical resin composition according to claim 1, wherein, The polymer (A) has a glass transition temperature (Tg) of -90.0°C or higher and -20.0°C or lower.

3. The optical resin composition according to claim 1, wherein, The polymer (A) has a glass transition temperature (Tg) above -80.0°C and below -30.0°C.

4. The optical resin composition according to claim 1, wherein, The polymer (A) has a glass transition temperature (Tg) above -75.0°C and below -35.0°C.

5. The optical resin composition according to claim 1, wherein, The aliphatic polyisocyanate has a weight-average molecular weight of 2,500 or more and 200,000 or less.

6. The optical resin composition according to claim 1, wherein, The aliphatic polyisocyanate has a weight-average molecular weight of 3,000 or more and 190,000 or less.

7. The optical resin composition according to claim 1, wherein, The aliphatic polyisocyanate has a weight-average molecular weight of 3,500 or more and 180,000 or less.

8. The optical resin composition according to claim 1, wherein, The aliphatic polyisocyanate has a weight-average molecular weight of 4,000 or more and 170,000 or less.

9. The optical resin composition according to claim 1, wherein, The molar ratio of the isocyanate group of the diisocyanate (b1) to the total molar ratio of the hydroxyl groups of the polyol (b2), NCO / OH, is 1.5 or more and 30.0 or less.

10. The optical resin composition according to claim 1, wherein, The number average molecular weight of the polyol (b2) is above 800 and below 12,000.

11. The optical resin composition according to claim 9, wherein, The ratio of NCO / OH is 2.0 or higher and 25.0 or lower.

12. The optical resin composition according to claim 9, wherein, The ratio of NCO / OH is 2.5 or higher and 22.0 or lower.

13. The optical resin composition according to claim 1, wherein, The aliphatic polyisocyanate has one or more functional groups selected from the group consisting of urethane groups and urea groups.

14. The optical resin composition according to claim 1, wherein, The aliphatic polyisocyanates include alicyclic polyisocyanates.

15. An optical resin composition comprising a polymer (A) and a crosslinking agent (B), wherein the polymer (A) is one or more selected from the group consisting of acrylic polymers, urethane polymers, and rubber polymers. The polymer (A) has a glass transition temperature (Tg) above -110.0℃ and below -10.0℃. The crosslinking agent component (B) comprises a polyisocyanate derived from at least one diisocyanate (b1) selected from aliphatic diisocyanates and a polyol (b2) having a number average molecular weight of 1100 or more and an average hydroxyl number of 1.5 or more and 2.5 or less. The molar ratio of the isocyanate group of the diisocyanate (b1) to the total molar ratio of the hydroxyl groups of the polyol (b2), NCO / OH, is 1.5 or more and 30.0 or less. The polyisocyanate has a weight-average molecular weight of 2100 or more and 200,000 or less. The polymer (A) comprises structural units derived from monomers containing crosslinking functional groups, wherein the crosslinking functional groups include one or more selected from the group consisting of hydroxyl, thiol, amino, amide, epoxy, and carboxyl groups. The content of the structural units derived from monomers containing crosslinking functional groups is 0.01% by mass and less than 30% by mass relative to the total mass of the polymer (A). The content of crosslinking agent component (B) relative to 100 parts by weight of polymer (A) is more than 0.05 parts by weight and less than 80.0 parts by weight. The polyisocyanate has an average number of isocyanate groups of 1.5 or more and 5.2 or less. The polyol (b2) is a difunctional polycaprolactone polyol.

16. The optical resin composition according to claim 15, wherein, The glass transition temperature (Tg) of the polymer (A) is above -105.0℃ and below -15.0℃.

17. The optical resin composition according to claim 15, wherein, The polymer (A) has a glass transition temperature (Tg) of -100.0°C or higher and -25.0°C or lower.

18. The optical resin composition according to claim 15, wherein, The polymer (A) has a glass transition temperature (Tg) of -100.0°C or higher and -40.0°C or lower.

19. The optical resin composition according to claim 15, wherein, The ratio of NCO / OH is 2.0 or higher and 25.0 or lower.

20. The optical resin composition according to claim 15, wherein, The ratio of NCO / OH is 2.2 or higher and 22.0 or lower.

21. The optical resin composition according to claim 15, wherein, The polyisocyanate has a weight-average molecular weight of 2,500 or more and 200,000 or less.

22. The optical resin composition according to claim 15, wherein, The polyisocyanate has a weight-average molecular weight of 3,000 or more and 200,000 or less.

23. The optical resin composition according to claim 15, wherein, The polyisocyanate has a weight-average molecular weight of 3,000 or more and 180,000 or less.

24. The optical resin composition according to claim 15, wherein, The polyisocyanate has a weight-average molecular weight of 3,000 or more and 150,000 or less.

25. The optical resin composition according to claim 15, wherein, The polyisocyanate has a weight-average molecular weight of 3200 or more and 150000 or less.

26. The optical resin composition according to claim 15, wherein, The polyisocyanate has an average number of isocyanate groups of 1.7 or more and 5.2 or less.

27. The optical resin composition according to claim 15, wherein, The polyisocyanate has an average number of isocyanate groups of 1.8 or more and 5.2 or less.

28. The optical resin composition according to claim 15, wherein, The polyisocyanate has one or more functional groups selected from the group consisting of urethane groups and urea groups. The molar ratio of isocyanurate groups relative to the total molar amount of urea carbamate groups, urea diketone groups, iminooxadiazine diketone groups, isocyanurate groups, urea groups, carbamate groups, and biuret groups is less than 50 mol%.

29. The optical resin composition according to claim 28, wherein, The molar ratio of the isocyanurate group is less than 45 mol% relative to the total molar amount of urea carbamate group, urea diketone group, iminooxadiazine diketone group, isocyanurate group, urea group, carbamate group and biuret group.

30. The optical resin composition according to claim 28, wherein, The molar ratio of the isocyanurate group is less than 40 mol% relative to the total molar amount of urea carbamate group, urea diketone group, iminooxadiazine diketone group, isocyanurate group, urea group, carbamate group and biuret group.

31. The optical resin composition according to claim 28, wherein, The molar ratio of the isocyanurate group is less than 35 moles relative to the total molar amount of urea carbamate group, urea diketone group, iminooxadiazine diketone group, isocyanurate group, urea group, carbamate group and biuret group.

32. The optical resin composition according to claim 15, wherein, The polyisocyanate comprises structural units derived from monools, diols, or polyoxyalkylene alkyl ethers having 2 or more but less than 18 carbon atoms.

33. The optical resin composition according to claim 15, wherein, The crosslinking agent component (B) was coated onto the release film and stored at 23°C and 65% humidity for 168 hours. Then, it was heated at 50°C for 24 hours. The resulting 50 μm thick cured film was peeled off from the release film and cut into pieces 10 mm wide and 40 mm long. The pieces were then placed in a tensile testing machine with a 20 mm gap between the clamps. The tensile strength in the tensile test performed at 23°C and 20 mm / min was 2 MPa or more and 100 MPa or less.

34. The optical resin composition according to claim 15, wherein, The crosslinking agent component (B) was coated onto the release film and stored at 23°C and 65% humidity for 168 hours, and then heated at 50°C for 24 hours. The resulting 50 μm thick cured film was then peeled off from the release film, and the haze value measured by a haze meter was less than 3.0%.

35. The optical resin composition according to claim 1 or 15, wherein, The content of the crosslinking agent component (B) is more than 0.05 parts by mass and less than 40.0 parts by mass relative to 100 parts by mass of the polymer (A).

36. The optical resin composition according to claim 1 or 15, wherein, The content of the crosslinking agent component (B) is more than 0.05 parts by mass and less than 30.0 parts by mass relative to 100 parts by mass of the polymer (A).

37. The optical resin composition according to claim 1 or 15, wherein, The polymer (A) has a weight-average molecular weight of 1.0 × 10⁻⁶. 3 Above and 5.0×10 6 the following.

38. The optical resin composition according to claim 37, wherein, The polymer (A) has a weight-average molecular weight of 3.0 × 10⁻⁶. 5 Above and 2.4×10 6 the following.

39. The optical resin composition according to claim 1 or 15, wherein, The crosslinking functional group is selected from one or more of the group consisting of hydroxyl, epoxy, carboxyl and amino groups.

40. The optical resin composition according to claim 1 or 15, wherein, The content of the structural units derived from the monomer containing cross-linking functional groups is more than 0.02% by mass and less than 25% by mass relative to the total mass of the polymer (A).

41. The optical resin composition according to claim 1 or 15, wherein, The content of the structural units derived from the monomer containing cross-linking functional groups is 0.03% by mass and less than 20% by mass relative to the total mass of the polymer (A).

42. The optical resin composition according to claim 1 or 15, wherein, The acrylic polymer comprises structural units of (meth)acrylate monomers derived from the ester terminus with 1 or more but less than 18 carbon atoms.

43. The optical resin composition according to claim 42, wherein, The content of structural units derived from (meth)acrylate monomers is more than 0.01% by mass and less than 99.99% by mass relative to the total mass of the acrylic polymer.

44. The optical resin composition according to claim 43, wherein, The content of structural units derived from (meth)acrylate monomers is more than 10% by mass and less than 99.99% by mass relative to the total mass of the acrylic polymer.

45. The optical resin composition according to claim 43, wherein, The content of structural units derived from (meth)acrylate monomers is more than 50% by mass and less than 99.99% by mass relative to the total mass of the acrylic polymer.

46. ​​The optical resin composition according to claim 43, wherein, The content of structural units derived from (meth)acrylate monomers is more than 60% by mass and less than 99.99% by mass relative to the total mass of the acrylic polymer.

47. The optical resin composition according to claim 43, wherein, The content of structural units derived from (meth)acrylate monomers is more than 80% by mass and less than 99.99% by mass relative to the total mass of the acrylic polymer.

48. The optical resin composition according to claim 1 or 15, wherein, The urethane polymer has an urethane group and one or more structures derived from the group consisting of polyesters, polyethers and polycarbonates.

49. The optical resin composition according to claim 1 or 15, wherein, The rubber-based polymer has one or more structures derived from the group consisting of styrene-butadiene rubber, polyisobutylene rubber, butyl rubber, and styrene-isoprene-styrene block copolymers.

50. The optical resin composition according to claim 9 or 15, wherein, Relative to 100 parts by weight of the diisocyanate (b1), The content of the polyol (b2) is more than 0.1 parts by mass and less than 900 parts by mass.

51. The optical resin composition according to claim 50, wherein, The content of the polyol (b2) is 1.0 parts by mass or more and 850.0 parts by mass or less, relative to 100 parts by mass of the diisocyanate (b1).

52. The optical resin composition according to claim 50, wherein, The content of the polyol (b2) is 2.0 parts by mass or more and 800 parts by mass or less, relative to 100 parts by mass of the diisocyanate (b1).

53. The optical resin composition according to claim 1 or 15, wherein, The aliphatic diisocyanate includes alicyclic diisocyanates.

54. The optical resin composition according to claim 1 or 15, wherein, The crosslinking agent component (B) has an isocyanate group content of 1.0% by mass or more and 9.5% by mass or less.

55. The optical resin composition according to claim 54, wherein, The crosslinking agent component (B) has an isocyanate group content of 1.5% by mass or more and 9.0% by mass or less.

56. The optical resin composition according to claim 54, wherein, The crosslinking agent component (B) has an isocyanate group content of 2.0% by mass or more and 8.7% by mass or less.

57. The optical resin composition according to claim 54, wherein, The crosslinking agent component (B) has an isocyanate group content of 2.0% by mass or more and 8.5% by mass or less.

58. The optical resin composition according to claim 54, wherein, The crosslinking agent component (B) has an isocyanate group content of 2.5% by mass or more and 8.3% by mass or less.

59. The optical resin composition according to claim 54, wherein, The crosslinking agent component (B) has an isocyanate group content of 2.8% by mass or more and 8.3% by mass or less.

60. The optical resin composition according to claim 1 or 15, wherein, The content of the polyisocyanate in the crosslinking agent component (B) is 50% by mass or more relative to the total mass of the crosslinking agent component (B).

61. The optical resin composition according to claim 60, wherein, The content of the polyisocyanate in the crosslinking agent component (B) is 70% by mass or more relative to the total mass of the crosslinking agent component (B).

62. The optical resin composition according to claim 60, wherein, The content of the polyisocyanate in the crosslinking agent component (B) is 90% by mass or more relative to the total mass of the crosslinking agent component (B).

63. The optical resin composition according to claim 60, wherein, The content of the polyisocyanate in the crosslinking agent component (B) is 100% by mass relative to the total mass of the crosslinking agent component (B).

64. The optical resin composition according to claim 1 or 15, wherein, The polymer (A) contains 0.01 to 0.50 parts by weight of a silane coupling agent (C) relative to 100 parts by weight.

65. The optical resin composition according to claim 1 or 15, wherein, The crosslinking agent component (B) further comprises one or more selected from the group consisting of isocyanate compounds other than the aliphatic polyisocyanate, carbodiimide compounds, oxazoline compounds, polyfunctional acrylate monomers, peroxides, titanium coupling agents, zirconium compounds, aluminum chelates, hydrazide compounds, epoxy crosslinking agents, thermal acid-producing agents, and photoacid-producing agents.

66. The optical resin composition according to claim 1 or 15, wherein, The crosslinking agent component (B) was coated onto the release film and stored at 23°C and 65% humidity for 168 hours. Then, it was heated at 50°C for 24 hours. The resulting 50 μm thick cured film was peeled off from the release film and cut into pieces 10 mm wide and 40 mm long. The pieces were then placed in a tensile testing machine with a 20 mm gap between the clamps. The tensile elongation was greater than 100% in a tensile test performed at 20 mm / min at 23°C.

67. An optical resin sheet, which is formed by curing the optical resin composition of claim 1 or 15 by heat or light.

68. The optical resin sheet according to claim 67, wherein, The thickness of the optical resin sheet is 1 μm or more and 1000 μm or less.

69. The optical resin sheet according to claim 67, wherein, An optical resin sheet with a single-sided polyethylene terephthalate film, 50 μm thick, 20 mm wide, and 100 mm long, was pressed onto an SUS304BA board as the substrate using a 2 kg roller in one pass. After curing at 23°C for 30 minutes, the 180-degree peel adhesion force measured at 23°C and 300 mm / min was 1.0 N / 20 mm or more and 100.0 N / 20 mm or less. The optical resin sheet was obtained as follows: the optical resin composition was coated on the polyethylene terephthalate film with a thickness of 25 μm, dried at 125°C for 3 minutes to cure it, and then stored at 23°C and 50% RH for 7 days.

70. The optical resin sheet according to claim 69, wherein, An optical resin sheet with a single-sided polyethylene terephthalate film, 50 μm thick, 20 mm wide, and 100 mm long, was pressed onto an SUS304BA board as the substrate using a 2 kg roller in one pass. After curing at 23°C for 30 minutes, the 180-degree peel adhesion force measured at 23°C and 300 mm / min was 2.0 N / 20 mm or more and 100.0 N / 20 mm or less. The optical resin sheet was obtained as follows: the optical resin composition was coated on the polyethylene terephthalate film with a thickness of 25 μm, dried at 125°C for 3 minutes to cure it, and then stored at 23°C and 50% RH for 7 days.

71. The optical resin sheet according to claim 67, wherein, An optical resin sheet with a single-sided polyethylene terephthalate film, 50 μm thick, 25 mm wide, and 130 mm long, was pressed onto an SUS304BA board (the substrate) with the width and length overlapping within a 25 mm range using a 2 kg roller in one round trip. The sheet was cured at 23°C for 1 hour, then further cured at 40°C for 30 minutes. A 500 g weight was then suspended from the lower end of the optical resin sheet at 40°C for 1 hour. After returning to the 23°C environment, the offset of the optical resin sheet was less than 2.00 mm. The optical resin sheet was obtained by coating the optical resin composition onto a 25 μm thick polyethylene terephthalate film, drying it at 125°C for 3 minutes to cure it, and then storing it at 23°C and 50% RH for 7 days.

72. The optical resin sheet according to claim 67, wherein, The optical resin composition was coated onto a 38 μm thick peel-treated polyethylene terephthalate film, dried at 125°C for 3 minutes to cure it, and then stored at 23°C and 50% RH for 7 days. The resulting 50 μm thick optical resin sheet was peeled off from the peel-treated polyethylene terephthalate film and pasted onto glass with a haze value of 0.1%. The haze value measured by a haze meter was 2.0% or less.

73. The optical resin sheet according to claim 67, wherein, The optical resin composition was coated onto a 38 μm thick peel-treated polyethylene terephthalate film, dried at 125°C for 3 minutes to cure it, and then stored at 23°C and 50% RH for 7 days. The film was then peeled off from the peel-treated polyethylene terephthalate film, and the resulting 50 μm thick optical resin sheet was stored at 23°C and 50% RH for 7 days. After being wrapped in a mesh sheet, the sheet was immersed in ethyl acetate at 23°C for 1 week and then dried at 120°C for 2 hours. The gel fraction calculated was 45.0% by mass or more and 99.9% by mass or less.

74. The optical resin sheet according to claim 73, wherein, The gel fraction is 60.0% by mass or more and 99.9% by mass or less.

75. The optical resin sheet according to claim 67, wherein, The optical resin composition was coated onto a 38 μm thick peel-treated polyethylene terephthalate film, dried at 125°C for 3 minutes to cure it, and then stored at 23°C and 50% RH for 7 days. The resulting 50 μm thick optical resin sheet was then peeled off from the peel-treated polyethylene terephthalate film and stacked in layers with a thickness of 200 μm. The sheets were then cut into 10 mm wide and 40 mm long pieces and placed in a tensile testing machine with a 10 mm gap between the clamps. The tensile modulus was 0.40 N / mm² in a tensile test performed at 23°C and 300 mm / min. 2 The following applies, and the elongation in the tensile test is 100% or more.

76. The optical resin sheet according to claim 75, wherein, The optical resin composition was coated onto a 38 μm thick peel-treated polyethylene terephthalate film, dried at 125°C for 3 minutes to cure it, and then stored at 23°C and 50% RH for 7 days. The resulting 50 μm thick optical resin sheet was then peeled off from the peel-treated polyethylene terephthalate film and stacked in layers with a thickness of 200 μm. The sheets were then cut into 10 mm wide and 40 mm long pieces and placed in a tensile testing machine with a 10 mm gap between the clamps. The tensile modulus was 0.40 N / mm² in a tensile test performed at 23°C and 300 mm / min. 2 The following applies, and the elongation in the tensile test is 200% or more.

77. The optical resin sheet according to claim 67, wherein, The optical resin sheet is an optical transparent adhesive sheet.

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