Adhesive tape for molding plastic lens and method for molding plastic lens molded article

Abstract

The problem to be solved by the invention is to provide an adhesive tape for molding a plastic lens capable of preventing generation of bubbles on an outer peripheral surface of a plastic lens molded article. The means for solving the problem is an adhesive tape for molding a plastic lens, the adhesive tape having a belt-like base material and an adhesive layer formed on one surface of the base material, wherein the adhesive layer is a cured product layer formed from a cured product of a silicone-based adhesive composition, the silicone-based adhesive composition including (1) silicone gum (G) including at least one selected from the group consisting of silicone gum (G1) having a silicon atom-bonded alkenyl group and silicone gum (G2) having a silicon atom-bonded hydroxy group, (2) a silicone resin (R), (3) an organopolysiloxane having three or more silicon atom-bonded hydrogen atoms in one molecule, and (4) a platinum group metal-based catalyst; and in the adhesive layer, a compression displacement amount (A) at 95°C determined by a TMA method of JIS K 7196 is 60% or more of the thickness of the adhesive layer.

Description

Adhesive tape for molding plastic lenses and method for molding plastic lens products

[0001] The present invention relates to an adhesive tape for molding plastic lenses and a method for molding plastic lenses, used when manufacturing standard molded products (hereinafter referred to as "plastic lens molded products") having the same thickness and curvature as final products such as plastic eyeglass lenses and optical lenses.

[0002] A conventional method for manufacturing plastic lenses is known, which involves arranging a pair of molds at a predetermined distance apart, forming a cavity between the pair of molds by attaching adhesive tape to the outer surfaces of the pair of molds, filling the cavity with polymerizable monomers, and polymerizing the polymerizable monomers.

[0003] Polymerizable monomers filling the cavity undergo thermal expansion due to heating or reaction heat (typically between 40°C and 70°C), increasing in volume beyond the initial reference volume. Subsequently, when the polymerization temperature range (typically between 60°C and 100°C) is reached, the polymerization reaction proceeds, causing the monomer to shrink below the initial reference volume.

[0004] Therefore, in the casting polymerization method, stress is placed on the adhesive tape used for molding plastic lenses during polymerization, which can easily lead to deterioration of the adhesive layer and incomplete sealing. In such cases, defects such as chipping, clouding, and air bubbles may occur in the molded plastic lens.

[0005] Patent Document 1 describes an adhesive tape for molding plastic lenses and a method for molding plastic lenses that can prevent chipping and whitening of the outer surface of molded plastic lenses, prevent adhesive residue from forming on the mold, and allow for stable use even after long-term storage.

[0006] Japanese Patent Publication No. 2014-129508

[0007] On the other hand, there is still room for improvement regarding the problem that air bubbles are likely to occur on the outer peripheral surface of a plastic lens molded article. In particular, the higher the refractive index of the polymerizable monomer for a plastic lens, the greater the volume change associated with the expansion and contraction of the monomer during polymerization, and there is a tendency for liquid leakage of the monomer to occur during polymerization. As a result, minute air bubbles are likely to occur on the outer peripheral surface of the plastic lens molded article, and thus improvement thereof is desired.

[0008] The present invention solves the above problems, and an object thereof is to provide an adhesive tape for molding a plastic lens capable of preventing air bubbles from occurring on the outer peripheral surface of the plastic lens molded article.

[0009] As a result of intensive studies to solve the above problems, the inventors of the present invention consider that flexibility that can easily follow the expansion and contraction of the monomer during polymerization of the polymerizable monomer for a plastic lens is important as a characteristic of the adhesive layer of the adhesive tape. If the amount of compression displacement at high temperature, which is an index of the flexibility of the adhesive layer, is within a predetermined range and the adhesive layer is easily deformed with low stress, it has been found that air bubbles can be prevented from occurring on the outer peripheral surface of the plastic lens molded article, and thus the present invention has been achieved.

[0010] The present invention provides the following aspects. [Aspect 1] A strip-shaped substrate and an adhesive layer formed on one surface of the substrate, wherein the adhesive layer comprises, as a base polymer, (1) a silicone gum (G) containing at least one selected from the group consisting of a silicone gum (G1) having an “alkenyl group bonded to a silicon atom” and a silicone gum (G2) having a “hydroxyl group bonded to a silicon atom”, (2) a silicone resin in which a silicone resin (R) is mixed, and further as a crosslinking agent, (3) an organopolysiloxane having three or more “hydrogen atoms bonded to a silicon atom” in one molecule, and as a crosslinking reaction catalyst, (4) a cured product layer composed of a cured product of a silicone-based adhesive composition containing a platinum group metal-based catalyst, and the adhesive layer has a compression displacement amount (A) at 95° C. determined by the TMA method of JIS K7196 of 60% or more, preferably 60 to 95%, more preferably 65 to 85%, still more preferably 70 to 80% of the thickness of the adhesive layer, an adhesive tape for plastic lens molding.

[0011] [Aspect 2] The adhesive tape for plastic lens molding according to Aspect 1, wherein the mass ratio G / R of the silicone gum (G) to the silicone resin (R) is 15.0 / 85.0 to 37.0 / 63.0, preferably 19.0 / 81.0 to 33.5 / 66.5, more preferably 25.0 / 75.0 to 30.0 / 70.0.

[0012] [Aspect 3] The total amount of the “alkenyl group bonded to a silicon atom” and the “hydroxyl group bonded to a silicon atom” in the silicone gum (G) is in the range of 0.0003 mol or more and less than 0.0004 mol per 100 g of the silicone gum (G), and the blending amount of the crosslinking agent is such that the molar ratio of the “hydrogen atom bonded to a silicon atom” in the crosslinking agent to the total amount of the “alkenyl group bonded to a silicon atom” and the “hydroxyl group bonded to a silicon atom” in the silicone gum (G) is 21.0 or more and less than 40.0, preferably 25.0 or more and less than 38.0, the adhesive tape for plastic lens molding according to Aspect 1 or 2.

[0013] [Aspect 4] The adhesive tape for molding plastic lenses according to aspect 1 or 2, wherein the total amount of "alkenyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) is in the range of 0.0004 moles or more and less than 0.00063 moles per 100 g of the silicone gum (G), and the amount of the crosslinking agent is such that the molar ratio of "hydrogen atoms bonded to silicon atoms" in the crosslinking agent to the total amount of "alkenyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) is 3.0 or more and less than 21.0, preferably 12.0 or more and less than 17.0.

[0014] [Aspect 5] The adhesive tape for molding plastic lenses according to aspect 1 or 2, wherein the total amount of "alkenyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) is in the range of 0.00063 moles or more and less than 0.0017 moles per 100 g of the silicone gum (G), and the amount of the crosslinking agent is such that the molar ratio of "hydrogen atoms bonded to silicon atoms" in the crosslinking agent to the total amount of "alkenyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) is 0.2 or more and less than 3.0, preferably 0.3 or more and less than 2.8.

[0015] [Aspect 6] A plastic lens molding adhesive tape, any one of aspects 1 to 5, wherein the silicone gum (G) comprises a silicone gum (G1) having an "alkenyl group bonded to a silicon atom" and a silicone gum (G2) having a "hydroxyl group bonded to a silicon atom".

[0016] [Aspect 7] The adhesive layer has a thickness of 10 to 50 μm, preferably 20 to 45 μm, and more preferably 25 to 43 μm, in any one of the embodiments 1 to 6, which is an adhesive tape for molding plastic lenses.

[0017] [Aspect 8] An adhesive tape for molding plastic lenses, any one of aspects 1 to 7, wherein the 70°C holding force to a polished SUS304 steel plate is 50 minutes or more and less than 1,440 minutes, preferably 550 minutes or more and 1,320 minutes or less, and the adhesive force to a polished SUS304 steel plate is 3.0 N / 10 mm or more and 6.0 N / 10 mm or less, preferably 3.5 N / 10 mm or more and 5.8 N / 10 mm or less.

[0018] [Aspect 9] A method for manufacturing a plastic lens molded product, comprising arranging a pair of molds at a predetermined distance apart, forming a cavity between the pair of molds by attaching any of the adhesive tapes for molding plastic lenses according to aspects 1 to 8 to the outer circumferential surfaces of the pair of molds, filling the cavity with polymerizable monomer, and polymerizing the polymerizable monomer.

[0019] [Aspect 10] A molded product manufactured using any one of the adhesive tapes for molding plastic lenses from aspects 1 to 8.

[0020] The present invention provides an adhesive tape for molding plastic lenses that can prevent air bubbles from forming on the outer surface of a molded plastic lens.

[0021] The following describes in detail one embodiment of the present invention, but the scope of the present invention is not limited to the embodiment described herein, and various modifications can be made without departing from the spirit of the invention. Furthermore, if multiple upper and lower limits are given for a particular parameter, any combination of these upper and lower limits can be used to create a suitable numerical range.

[0022] [Adhesive Tape for Plastic Lens Molding] The adhesive tape for plastic lens molding of the present invention (hereinafter sometimes referred to as "adhesive tape") comprises a strip-shaped tape base material and an adhesive layer provided on almost the entire surface of one side of the tape base material.

[0023] (Adhesive layer) The adhesive layer is composed of a cured layer made from a cured product of a silicone-based adhesive composition. The thickness of the adhesive layer is, for example, 10 to 50 μm, preferably 20 to 45 μm, and more preferably 25 to 43 μm. Having the thickness of the adhesive layer within the above range makes it easier to adjust the flexibility of the adhesive layer to a desired range.

[0024] The adhesive layer used in this invention exhibits excellent flexibility when heated to the polymerization temperature of the polymerizable monomer. Therefore, the adhesive layer used in this invention can easily follow the deformation when the polymerizable monomer expands and contracts during polymerization. This also reduces the peeling force (stress) acting at the boundary between the mold and the adhesive layer. In other words, the adhesive layer becomes less likely to peel off from the outer surface of the mold, preventing leakage of the polymerizable monomer, and as a result, preventing the formation of air bubbles on the outer surface of the plastic lens molded product.

[0025] The flexibility of the adhesive layer when heated can be determined by the thermomechanical analysis (TMA) method according to JIS K7196. This method involves measuring the deformation of a thermoplastic film and sheet test specimen as a function of temperature or time under a non-vibrational load while changing the temperature of the specimen according to a specific program.

[0026] The adhesive layer used in this invention is cooled to -60°C ± 20°C, then a load of 98 mN is applied to a probe (1 mmφ), and the temperature is raised to 150°C at a rate of 10°C / min. Under these measurement conditions, the compressive displacement (A) at 95°C, determined by the TMA method, is 60% or more of the thickness of the adhesive layer, preferably 60-95%, more preferably 65-85%, and even more preferably 70-80%. If the compressive displacement (A) is less than 60%, air bubbles are likely to form on the outer surface of the plastic lens molded product. If the compressive displacement (A) is too large, a portion of the adhesive layer may remain on the outer surface of the plastic lens molded product (adhesive residue).

[0027] The flexibility of the adhesive layer when heated varies depending on the cohesive force or degree of crosslinking of the silicone-based adhesive composition, and can be adjusted by appropriately changing the type and formulation of the silicone resin (polyorganosiloxane) contained in the silicone-based adhesive composition, as well as the type and amount of crosslinking agent added.

[0028] (Silicone-based adhesive composition) The silicone-based adhesive composition used in the present invention includes a silicone resin as the base polymer of the adhesive, which is a mixture of component (1), which is silicone gum (G), and component (2), which is silicone resin (R). Furthermore, it includes component (3), which is an organopolysiloxane having three or more "hydrogen atoms bonded to silicon atoms" in one molecule, as a crosslinking agent, and component (4), which is a platinum group metal catalyst, as a catalyst to promote the reaction of the crosslinking agent. The silicone gum (G) includes at least one selected from the group consisting of silicone gum (G1) having "alkenyl groups bonded to silicon atoms" and silicone gum (G2) having "hydroxyl groups bonded to silicon atoms". The alkenyl groups are bonded to silicon atoms at the molecular chain ends and side chains of silicone gum (G1), and the hydroxyl groups are mainly bonded to silicon atoms at the molecular chain ends of silicone gum (G2), and each becomes a crosslinking site that reacts with the "hydrogen atoms bonded to silicon atoms" of the crosslinking agent. The silicone gum (G) may optionally include a non-functional silicone gum (G3) that does not have either an "alkenyl group bonded to a silicon atom" or a "hydroxyl group bonded to a silicon atom." The silicone gum (G3) is, for example, a silicone gum that does not have crosslinking sites that can react with the "hydrogen atom bonded to a silicon atom" of the crosslinking agent. In this disclosure, "non-functional" means that the silicone gum does not have functional groups that exhibit reactivity or polymerizability with other functional groups, such as hydroxyl groups, silanol groups, hydrosilyl groups, alkenyl groups, acrylic groups, methacrylic groups, epoxy groups, amino groups, mercapto groups, etc.

[0029] ≪Component (1): Silicone Gum (G)≫ The silicone adhesive composition used in the present invention contains component (1), which is silicone gum (G), as a silicone resin. The silicone gum (G) includes at least one selected from the group consisting of silicone gum (G1) having an alkenyl group bonded to a silicon atom and silicone gum (G2) having a hydroxyl group bonded to a silicon atom.

[0030] The silicone gum (G1) or (G2) may have an alkenyl group bonded to a silicon atom and a hydroxyl group bonded to a silicon atom.

[0031] <Silicone gum (G1) having "alkenyl groups bonded to silicon atoms"> The silicone gum (G1) having "alkenyl groups bonded to silicon atoms" (hereinafter also simply referred to as "silicone gum (G1) having alkenyl groups" or "silicone gum (G1)") is an organopolysiloxane having "alkenyl groups bonded to silicon atoms" in its molecule. Typical examples include, for example, an organopolysiloxane having at least two "alkenyl groups bonded to silicon atoms" in one molecule, in which the alkenyl groups are present at a concentration of 0.0002 to 0.05 moles per 100 g of the organopolysiloxane (silicone gum (G1) having alkenyl groups).

[0032] Examples of molecular structures of the organopolysiloxane of the silicone gum (G1) having the aforementioned "alkenyl group bonded to a silicon atom" include a linear structure in which the main chain consists of repeating diorganosiloxane units, a structure that includes branched chains as part of the molecular structure, a branched chain structure, or a cyclic structure. Among these, a linear organopolysiloxane is preferred from the viewpoint of physical properties such as the mechanical strength of the adhesive layer.

[0033] Examples of the silicone gum (G1) having the aforementioned "alkenyl group bonded to a silicon atom" include, but are not limited to, organopolysiloxanes represented by the following general formula (1).

[0034]

[0035] (In the formula, R１ (Independently, each is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms and lacking an aliphatic unsaturated bond, or an alkenyl group-containing organic group having 2 to 10 carbon atoms, of which two or more are alkenyl group-containing organic groups. n is an integer from 50 to 15,000.)

[0036] In formula (1) above, R １ R is independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, that does not have an aliphatic unsaturated bond, or an alkenyl group-containing organic group having 2 to 10 carbon atoms, preferably 2 to 8 carbon atoms, of which two or more are alkenyl group-containing organic groups. １ Examples of unsubstituted or substituted monovalent hydrocarbon groups having 1 to 10 carbon atoms and lacking aliphatic unsaturated bonds include alkyl groups such as methyl, ethyl, propyl, and butyl groups; cycloalkyl groups such as cyclohexyl groups; aryl groups such as phenyl groups; and trifluoromethyl groups, 3,3,3-trifluoropropyl groups, etc., in which some or all of the hydrogen atoms bonded to the carbon atoms of these groups are substituted with halogen atoms. Among these, aliphatic saturated hydrocarbon groups or aromatic hydrocarbon groups are preferred, and methyl and phenyl groups are particularly preferred.

[0037] Also, the R １ The organic group containing an alkenyl group having 2 to 10 carbon atoms is preferably one having 2 to 8 carbon atoms, and examples include alkenyl groups such as vinyl, allyl, hexenyl, and octenyl groups; acryloylalkyl and methacryloylalkyl groups such as acryloylpropyl, acryloylmethyl, and methacryloylpropyl groups; cycloalkenylalkyl groups such as cyclohexenylethyl groups; and alkenyloxyalkyl groups such as vinyloxypropyl groups, with vinyl groups being particularly preferred.

[0038] In formula (1) above, n is a positive number between 50 and 15,000, preferably between 200 and 12,000. If n is less than 50, the number of crosslinking points becomes too large, which can actually decrease the reactivity with the crosslinking agent and reduce the holding power (cohesive force) of the resulting adhesive layer. If n exceeds 15,000, the viscosity of the adhesive composition becomes very high, which can make it difficult to stir and mix, resulting in poor workability.

[0039] The weight-average molecular weight (Mw) of the silicone gum (G1) having "alkenyl groups bonded to silicon atoms" is not particularly limited, but is preferably 4,000 to 1,100,000, more preferably 15,000 to 880,000, and even more preferably 450,000 to 700,000. If the weight-average molecular weight (Mw) is less than 4,000, the number of crosslinking points will be too large, which may reduce the reactivity with the crosslinking agent and decrease the holding power (cohesive force) of the resulting adhesive layer. If the weight-average molecular weight (Mw) exceeds 1,100,000, the viscosity of the adhesive composition will be very high, which may make it difficult to stir and mix, resulting in poor workability.

[0040] The amount of alkenyl groups contained in the silicone gum (G1) having "alkenyl groups bonded to silicon atoms" can be appropriately adjusted according to the amount of other silicone gums (G2) and (G3) and the amount of "hydroxyl groups bonded to silicon atoms" in the silicone gum (G2), and is not particularly limited, but is preferably 0.0002 to 0.05 moles per 100 g of organopolysiloxane (silicone gum (G1) having alkenyl groups), more preferably 0.0004 to 0.03 moles, and even more preferably 0.0006 to 0.01 moles. If the amount of alkenyl groups is less than 0.0002 moles, the crosslinking density will be small when the adhesive composition is cured, and the holding power (cohesive force) of the resulting adhesive layer may decrease. Conversely, if it exceeds 0.05 moles, the resulting adhesive layer will be hard, and appropriate adhesive strength and desired flexibility (compression displacement (A)) may not be obtained.

[0041] The silicone gum (G1) having the aforementioned "alkenyl group bonded to a silicon atom" can be used alone or in combination of two or more types.

[0042] In some embodiments, specific examples of silicone gum (G1) having the "alkenyl group bonded to a silicon atom" include dimethylpolysiloxane with dimethylvinylsiloxy groups sealed at both ends of the molecular chain, dimethylsiloxane / methylvinylsiloxane copolymer with dimethylvinylsiloxy groups sealed at both ends of the molecular chain, dimethylsiloxane / methylphenylsiloxane copolymer with dimethylvinylsiloxy groups sealed at both ends of the molecular chain, methylphenylpolysiloxane with dimethylvinylsiloxy groups sealed at both ends of the molecular chain, and trimethylsiloxy group sealed at both ends of the molecular chain. Examples include dimethylsiloxane / methylvinylsiloxane copolymer, dimethylsiloxane / methylvinylsiloxane / methylphenylsiloxane copolymer with trimethylsiloxy groups sealed at both ends of the molecular chain, dimethylsiloxane / methylhexenylsiloxane copolymer with trimethylsiloxy groups sealed at both ends of the molecular chain, dimethylsiloxane / methylhexenylsiloxane copolymer with dimethylvinylsiloxy groups sealed at both ends of the molecular chain, and dimethylsiloxane / methylhexenylsiloxane copolymer with dimethylhexenylsiloxy groups sealed at both ends of the molecular chain. Among these, those having alkenyl groups at both ends of the molecular chain and on the side chains, i.e., having an average of three or more alkenyl groups per molecule, are preferred from the viewpoint of imparting appropriate cohesive force and a certain degree of flexibility to the resulting adhesive layer, as well as from the viewpoint of versatility, and more preferably those that do not have aryl groups such as phenyl groups on the side chains. Specifically, examples of such copolymers include dimethylsiloxane / methylvinylsiloxane copolymers with dimethylvinylsiloxy groups sealed at both ends of the molecular chain, dimethylsiloxane / methylhexenylsiloxane copolymers with dimethylvinylsiloxy groups sealed at both ends of the molecular chain, and dimethylsiloxane / methylhexenylsiloxane copolymers with dimethylhexenylsiloxy groups sealed at both ends of the molecular chain. It is preferable to use one of these copolymers alone or in combination of two or more.

[0043] In some preferred embodiments, the silicone gum (G1) having "alkenyl groups bonded to silicon atoms" may be, for example, an organopolysiloxane having an average of 3 or more alkenyl groups per molecule with a weight-average molecular weight (Mw) of 450,000 to 700,000. In this case, the average number of alkenyl groups in one molecule (the total number of alkenyl groups bonded to silicon atoms at both ends and the side chains) may be, for example, 3 to 10. The amount of alkenyl groups contained in the silicone gum (G1) having alkenyl groups may be, for example, 0.00042 to 0.0022 moles per 100 g of the silicone gum (G1) having alkenyl groups.

[0044] <Silicone gum (G2) having "hydroxyl groups bonded to silicon atoms"> The silicone gum (G2) having "hydroxyl groups bonded to silicon atoms" (hereinafter also simply referred to as "silanol groups" or "Si-OH groups") (hereinafter also simply referred to as "silicone gum (G2) having silanol groups" or "silicone gum (G2)") is an organopolysiloxane having "hydroxyl groups bonded to silicon atoms" (silanol groups) in its molecule. Typical examples include, for example, an organopolysiloxane having at least two "hydroxyl groups bonded to silicon atoms" in one molecule, and the "hydroxyl groups bonded to silicon atoms" are contained in a concentration of 0.0002 to 0.05 moles per 100 g of the organopolysiloxane [silicone gum (G2) having silanol groups]. Furthermore, it is preferable that the silicone gum (G2) having "hydroxyl groups bonded to silicon atoms" does not have alkenyl groups in its molecule.

[0045] Examples of the molecular structure of the organopolysiloxane of the silicone gum (G2) having "hydroxyl groups bonded to silicon atoms" include a linear structure in which the main chain consists of repeating diorganosiloxane units, a structure that includes branched chains as part of the molecular structure, a branched chain structure, or a cyclic structure. Among these, a linear organopolysiloxane is preferred from the viewpoint of physical properties such as the mechanical strength of the adhesive layer.

[0046] Examples of the silicone gum (G2) having "hydroxyl groups bonded to silicon atoms" include, but are not limited to, organopolysiloxanes represented by the following general formula (2).

[0047]

[0048] (In the formula, R ２ (m is an unsubstituted or substituted monovalent hydrocarbon group with 1 to 10 carbon atoms and no aliphatic unsaturated bonds. m is an integer from 50 to 15,000.)

[0049] In the above formula (2), R ２ R is an independent unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms and lacking an aliphatic unsaturated bond. ２ Examples of unsubstituted or substituted monovalent hydrocarbon groups having 1 to 10 carbon atoms and lacking aliphatic unsaturated bonds include alkyl groups such as methyl, ethyl, propyl, and butyl groups; cycloalkyl groups such as cyclohexyl groups; aryl groups such as phenyl groups; and trifluoromethyl groups, 3,3,3-trifluoropropyl groups, etc., in which some or all of the hydrogen atoms bonded to the carbon atoms of these groups are substituted with halogen atoms. Among these, aliphatic saturated hydrocarbon groups or aromatic hydrocarbon groups are preferred, and methyl and phenyl groups are particularly preferred.

[0050] In formula (2) above, m is a positive number between 50 and 15,000, preferably between 200 and 12,000. If m is less than 50, the number of crosslinking points becomes too large, which can actually decrease the reactivity with the crosslinking agent and reduce the holding power (cohesive force) of the resulting adhesive layer. If m exceeds 15,000, the viscosity of the adhesive composition becomes very high, which can make it difficult to stir and mix, resulting in poor workability.

[0051] The weight-average molecular weight (Mw) of the silicone gum (G2) having "hydroxyl groups bonded to silicon atoms" is not particularly limited, but is preferably 4,000 to 1,100,000, more preferably 15,000 to 880,000, and even more preferably 450,000 to 700,000. If the weight-average molecular weight (Mw) is less than 4,000, the number of crosslinking points may increase too much, which may decrease the reactivity with the crosslinking agent and reduce the holding power (cohesive force) of the resulting adhesive layer. If the weight-average molecular weight (Mw) exceeds 1,100,000, the viscosity of the adhesive composition becomes very high, which may make it difficult to stir and mix, resulting in poor workability.

[0052] The amount of hydroxyl groups (silanol groups) bonded to silicon atoms in the silicone gum (G2) having the aforementioned "hydroxyl groups bonded to silicon atoms" can be appropriately adjusted according to the amounts of other silicone gums (G1) and (G3) and the amount of alkenyl groups in the silicone gum (G1), and is not particularly limited, but is preferably 0.0002 to 0.03 moles per 100 g of organopolysiloxane (silicone gum (G2) having silanol groups), more preferably 0.0003 to 0.02 moles, and even more preferably 0.004 to 0.007 moles. If the amount of "hydroxyl groups bonded to silicon atoms" is less than 0.0002 moles, the crosslinking density may decrease when the silicone adhesive composition is cured, resulting in a decrease in the holding power (cohesive force) of the resulting adhesive layer. Conversely, if it exceeds 0.05 moles, the resulting adhesive layer may become hard, making it difficult to obtain appropriate adhesive strength or the desired compressive displacement (A), and the storage stability of the adhesive composition may deteriorate due to the effects of dehydration condensation between silanol groups.

[0053] The silicone gum (G2) having the aforementioned "hydroxyl group bonded to a silicon atom" can be used alone or in combination of two or more types.

[0054] In some embodiments, the amount of "hydroxyl groups bonded to silicon atoms" (silanol groups) contained in 100 g of silicone gum (G2) having "hydroxyl groups bonded to silicon atoms" is preferably less than the amount of "alkenyl groups bonded to silicon atoms" contained in 100 g of silicone gum (G1) having "alkenyl groups bonded to silicon atoms," from the viewpoint of imparting appropriate flexibility to the resulting adhesive layer. In this case, the crosslinking structure of the silicone gum (G) in the silicone resin of the adhesive composition can include a crosslinking form in which the distance between the crosslinking points of the silicone gum (G) is appropriately large. As a result, the silicone gum (G) moves more easily in the resulting adhesive layer, and it becomes easier to obtain an adhesive layer that can be deformed with lower stress.

[0055] In some embodiments, specific examples of organopolysiloxane (G2) having "hydroxyl groups bonded to silicon atoms" include dimethylpolysiloxane having silanol groups at both ends of the molecular chain, dimethylsiloxane-methylphenylsiloxane copolymer having silanol groups at both ends of the molecular chain, methylphenylpolysiloxane having silanol groups at both ends of the molecular chain, dimethylpolysiloxane having silanol groups at both ends of the molecular chain and on the side chain, dimethylsiloxane-methylphenylsiloxane copolymer having silanol groups at both ends of the molecular chain and on the side chain, and methylphenylpolysiloxane having silanol groups at both ends of the molecular chain and on the side chain. Among these, from the viewpoint of imparting appropriate flexibility to the resulting adhesive layer and from the viewpoint of versatility, those having silanol groups at both ends of the molecular chain but not on the side chain, i.e., those having silanol groups only at both ends of the molecular chain, are preferred, and those not having ring structures such as cycloalkyl groups or aryl groups on the side chain are even more preferred. Examples of such materials include dimethylpolysiloxanes having silanol groups only at both ends of the molecular chain, and it is preferable to use one type alone or a combination of two or more types with different molecular weights.

[0056] In some preferred embodiments, the organopolysiloxane (G2) having a "hydroxyl group bonded to a silicon atom" (silanol group) may be, for example, an organopolysiloxane having silanol groups only at both ends of a molecular chain with a weight average molecular weight (Mw) of 450,000 to 700,000. In this case, the amount of silanol groups contained in the organopolysiloxane (G2) having silanol groups may be, for example, 0.00028 to 0.00044 mol per 100 g of the silicone gum (G2) having silanol groups.

[0057] <Non-functional silicone gum (G3)> The non-functional silicone gum (G3) (hereinafter also simply referred to as "silicone gum (G3)") is a non-functional organopolysiloxane having neither an alkenyl group nor a silanol group in the molecule, and is an optional component optionally added to the silicone gum (G).

[0058] As the molecular structure of the organopolysiloxane of the non-functional silicone gum (G3), for example, a linear structure in which the main chain portion is composed of repeating units of diorganosiloxane, a structure including a branched chain in a part of the molecular structure, a branched chain structure, or a cyclic structure can be mentioned. Among them, from the viewpoint of physical properties such as the mechanical strength of the adhesive layer, an organopolysiloxane having a linear structure is preferable.

[0059] Examples of the non-functional silicone gum (G3) include, but are not limited to, organopolysiloxanes represented by the following general formula (3).

[0060]

[0061] (In the formula, R ３ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond with 1 to 10 carbon atoms. l is an integer of 50 to 15,000.)

[0062] The R ３Examples of unsubstituted or substituted monovalent hydrocarbon groups having 1 to 10 carbon atoms and lacking aliphatic unsaturated bonds include alkyl groups such as methyl, ethyl, propyl, and butyl groups; cycloalkyl groups such as cyclohexyl groups; aryl groups such as phenyl groups; and trifluoromethyl groups, 3,3,3-trifluoropropyl groups, etc., in which some or all of the hydrogen atoms bonded to the carbon atoms of these groups are substituted with halogen atoms. Among these, aliphatic saturated hydrocarbon groups or aromatic hydrocarbon groups are preferred, and methyl and phenyl groups are particularly preferred.

[0063] In formula (1) above, l is a positive number between 50 and 15,000, preferably between 200 and 12,000. If l is less than 50, the holding power (cohesive force) of the resulting adhesive layer may decrease, and if l exceeds 15,000, the viscosity of the adhesive composition becomes very high, which may make it difficult to stir and mix, resulting in poor workability.

[0064] The weight-average molecular weight (Mw) of the non-functional silicone gum (G3) is not particularly limited, but is preferably 4,000 to 1,100,000, more preferably 15,000 to 880,000, and even more preferably 450,000 to 700,000. If the weight-average molecular weight (Mw) exceeds 1,100,000, the viscosity of the adhesive composition becomes very high, which can make it difficult to stir and mix, resulting in poor workability.

[0065] The non-functional silicone gum (G3) can be used alone or in combination of two or more types. In some preferred embodiments, specific examples of the non-functional silicone gum (G3) include trimethylsiloxy group-sealed dimethylpolysiloxane at both ends of the molecular chain, trimethylsiloxy group-sealed dimethylsiloxane / methylphenylsiloxane copolymer, and trimethylsiloxy group-sealed methylphenylpolysiloxane at both ends of the molecular chain. Among these, trimethylsiloxy group-sealed dimethylpolysiloxane at both ends of the molecular chain is preferred from the viewpoint of imparting appropriate flexibility to the resulting adhesive layer and from the viewpoint of versatility.

[0066] In some preferred embodiments, the non-functional silicone gum (G3) may be an organopolysiloxane having a weight-average molecular weight (Mw) of 450,000 to 700,000, which is equivalent to that of the alkenyl group-containing silicone gum (G1) and the silanol group-containing silicone gum (G2) in the preferred embodiments.

[0067] ≪Component (2): Silicone Resin (R)≫ The silicone adhesive composition used in the present invention contains component (2), which is silicone resin (R), together with component (1), which is silicone gum (G). The silicone resin (R) functions as a tackifier for the silicone adhesive composition. The silicone resin (R) is a solid organopolysiloxane having a three-dimensional network structure, a typical example of which is the average unit formula; (R ４ ３ SiO １／２ ) ｘ (SiO ４／２ ) １．０ (In the formula, R ４ An example is an organopolysiloxane, so-called silicone resin (MQ resin), represented by (R), where is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms that does not independently have an aliphatic unsaturated bond, and x is a number from 0.5 to 1.0. In MQ resin, each M unit (R ４ ３ SiO １／２ ) is the Q unit (SiO ４／２ ) are coupled, and each Q unit is coupled to at least one other Q unit, and some Q units are coupled to only other Q units.

[0068] In the above average unit formula, R ４ R is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms that does not independently have an aliphatic unsaturated bond. Examples of unsubstituted or substituted monovalent hydrocarbon groups having 1 to 10 carbon atoms that do not have an aliphatic unsaturated bond include alkyl groups having 1 to 6 carbon atoms such as methyl, ethyl, propyl, and butyl groups; and aryl groups having 6 to 10 carbon atoms such as phenyl and tolyl groups. １ A methyl group is preferred as the group.

[0069] The aforementioned silicone resin (R) is R to the extent that it does not impair the properties of the present invention. ４ In addition, hydroxyl groups and hydrolyzable alkoxy groups may be included, and their content should be 0 to 4.0% by mass of the total mass of the silicone resin (R) component. If the content of the hydroxyl groups or alkoxy groups is greater than 4.0% by mass, the tack of the adhesive layer may decrease. Examples of the alkoxy groups include methoxy groups, ethoxy groups, isopropoxy groups, butoxy groups, and phenoxy groups, and methoxy groups are preferred when used.

[0070] In the above average unit formula, x is (SiO ４／２ (R) for units １ ３ SiO １／２ This represents the molar ratio in units and is a number between 0.5 and 1.0. If x is less than 0.5, the adhesive strength and tack of the resulting adhesive layer may decrease, and if x exceeds 1.0, the adhesive strength and holding power (cohesive force) of the resulting adhesive layer 2 may decrease.

[0071] The silicone resin (R) can be specifically described as, for example, an organopolysiloxane resin composed of siloxane units shown in the following formula. In the formula, Me is a methyl group. x1 and (x2 + x3) are numbers from 0.5 to 1.0.

[0072] ・(Me ３ SiO １／２ ) Ｘ１ (SiO ４／２ ) １．０ ・(Me ３ SiO １／２ ) Ｘ２ (HOME) ２ SiO １／２ ) Ｘ３ (SiO ４／２ ) １．０ ・(Me ３ SiO １／２ ) Ｘ２ (MeOMe) ２ SiO １／２ ) Ｘ３ (SiO ４／２ ) １．０

[0073] Among these, the formula (Me３ SiO １／２ ) Ｘ１ (SiO ４／２ ) １．０ It is preferable to use MQ resin as shown.

[0074] Furthermore, the silicone resin (R) is used within the limits that do not impair the properties of the present invention. ４ SiO ３／２ Unit, R ４ ２ SiO ２／２ Unit (R ４ It may contain the same as above. ４ SiO ３／２ Units and R ４ ２ SiO ２／２ If units are included, their proportion is preferably 1 to 20% by mass of the total mass of the silicone resin (R) component, and more preferably 3 to 15% by mass.

[0075] The silicone resin (R) can be used alone or in combination of two or more types.

[0076] The weight-average molecular weight (Mw) of the silicone resin (R) is not particularly limited, but is preferably 500 to 10,000 from the viewpoint of optimizing the adhesive properties of the resulting adhesive layer, and is more preferably 1,000 to 8,000 from the viewpoint of suppressing whitening of the plastic lens obtained by the dissolution of the silicone resin (R) into the lens monomer during polymerization of the lens monomer and from the viewpoint of imparting appropriate cohesive force.

[0077] <Mass ratio of silicone gum (G) to silicone resin (R)> The adhesive tape of the present invention can adjust the adhesive strength and holding power of its adhesive layer by changing the mass ratio of silicone gum (G) to silicone resin (R) in the adhesive composition. However, from the viewpoint of appropriately maintaining the adhesive strength and holding power while making it easier to adjust the compressive displacement amount (A), which is an indicator of flexibility as described above, to a desired range, in some embodiments, the mass ratio (G) / (R) of silicone gum (G) to silicone resin (R) in the adhesive composition of the present invention is preferably in the range of (G) / (R) = 15.0 / 85.0 to 37.0 / 63.0, more preferably in the range of 19.0 / 81.0 to 33.5 / 66.5, and even more preferably in the range of 25.0 / 75.0 to 30.0 / 70.0. When the mass ratio (G) / (R) is within the aforementioned range, the adhesive strength and holding power of the adhesive layer are appropriately maintained, while the compressive displacement (A), which is an indicator of flexibility, can be easily adjusted to the desired range. When two or more types of silicone gum are used in combination as silicone gum (G), their total mass is considered the mass of silicone gum (G), and when two or more types of silicone resin are used in combination as silicone resin (R), their total mass is considered the mass of silicone resin (R).

[0078] <Ratio of silicone gums (G1), (G2), and (G3) in the silicone gum (G) component> The silicone gum (G) includes at least one selected from the group consisting of silicone gum (G1) having an "alkenyl group bonded to a silicon atom" and silicone gum (G2) having a "hydroxyl group bonded to a silicon atom," and optionally includes non-functional silicone gum (G3). That is, the silicone gum (G) used in the adhesive layer of the present invention can be any of the following configurations selected from the group: (A): silicone gum (G1), (B): silicone gum (G2), (C): silicone gum (G1) + silicone gum (G2), (D): silicone gum (G1) + silicone gum (G3), (E): silicone gum (G2) + silicone gum (G3), (F): silicone gum (G1) + silicone gum (G2) + silicone gum (G3). When using a mixture of two or more silicone gum components as the silicone gum (G), as shown in the above configurations (C), (D), (E), and (F), the amount of each silicone gum component to be blended should be appropriately determined so that the compressive displacement (A) at 95°C, determined by the TMA method of JIS K7196 for the resulting adhesive layer, is 60% or more of the thickness of the adhesive layer. There are no particular limitations, but several embodiments are exemplified below.

[0079] In some preferred embodiments, from the viewpoint of achieving a good balance between the adhesive properties (adhesion strength, cohesive force) and flexibility of the adhesive layer, the silicone gum (G) may be any of the above configurations: (B): silicone gum (G2), (C): silicone gum (G1) + silicone gum (G2), (E): silicone gum (G2) + silicone gum (G3), (F): silicone gum (G1) + silicone gum (G2) + silicone gum (G3). Among these, from the viewpoint of achieving the above balance more stably, a more preferred embodiment of the silicone gum (G) is any of the above configurations that include silicone gum (G1) and silicone gum (G2): (C): silicone gum (G1) + silicone gum (G2), (F): silicone gum (G1) + silicone gum (G2) + silicone gum (G3). As mentioned above, by including silicone gum (G2) in silicone gum (G), a cross-linked structure with appropriately large distances between cross-linking points can be formed in silicone gum (G), making it easier to impart appropriate flexibility to the resulting adhesive layer for plastic lens molding.

[0080] In some more preferred embodiments, when the silicone gum (G) is used as a mixture of a silicone gum (G1) having "alkenyl groups bonded to silicon atoms" and a silicone gum (G2) having "hydroxyl groups bonded to silicon atoms," and optionally a non-functional silicone rubber (G3), each silicone gum component may contain, for example, 45 to 70 parts by mass of the silicone gum (G1) having "alkenyl groups bonded to silicon atoms," 10 to 55 parts by mass of the silicone gum (G2) having "hydroxyl groups bonded to silicon atoms," and 0 to 20 parts by mass of the non-functional silicone gum (G3), based on 100 parts by mass of the silicone gum (G). More preferably, it contains 55 to 68 parts by mass of the silicone gum (G1) having "alkenyl groups bonded to silicon atoms," 12.5 to 43 parts by mass of the silicone gum (G2) having "hydroxyl groups bonded to silicon atoms," and 0 to 19.5 parts by mass of the non-functional silicone gum (G3). The blending of each silicone gum component can be adjusted as appropriate so that the total mass of each silicone rubber component is 100 parts by mass within the respective ranges described above. Furthermore, regarding the amount of functional groups in the silicone rubber component, from the viewpoint of balancing the adhesive properties and flexibility of the adhesive layer, it is preferable that the amount (moles) of "silicon-bonded hydroxyl groups" (silanol groups) contained in 100g of silicone gum (G2) having "hydroxyl groups bonded to silicon atoms" is less than the amount (moles) of "silicon-bonded alkenyl groups" contained in 100g of silicone gum (G1) having "alkenyl groups bonded to silicon atoms".

[0081] Furthermore, in some preferred embodiments, when using any of the above configurations (B): silicone gum (G2) or (E): silicone gum (G2) + silicone gum (G3) as the silicone gum (G), each silicone gum component may contain, based on 100 parts by mass of silicone gum (G), for example, 40 to 100 parts by mass of silicone gum (G2) having "hydroxyl groups bonded to silicon atoms" and 0 to 60 parts by mass of non-functional silicone gum (G3), preferably within the range of 80 to 100 parts by mass of silicone gum (G2) and 0 to 20 parts by mass of non-functional silicone gum (G3).

[0082] Furthermore, in some embodiments, when using any of the above configurations (A): silicone gum (G1) or (D): silicone gum (G1) + silicone gum (G3) as the silicone gum (G), each silicone gum component may contain, based on 100 parts by mass of silicone gum (G), for example, 30 to 100 parts by mass of silicone gum (G1) having an alkenyl group bonded to a silicon atom, and 0 to 70 parts by mass of non-functional silicone gum (G3). Preferably, it may contain 30 to 93 parts by mass of silicone gum (G1) and 7 to 70 parts by mass of non-functional silicone gum (G3).

[0083] <Amount of Functional Groups in Silicone Gum (Component G)> As described above, the silicone gum (G) contains "alkenyl groups bonded to silicon atoms" and / or "hydroxyl groups bonded to silicon atoms" as functional groups. The amount of these functional groups in the silicone gum (G) component can be adjusted as appropriate so that the compressive displacement (A) at 95°C, determined by the TMA method of JIS K7196 for the resulting adhesive layer, is 60% or more of the thickness of the adhesive layer. There are no particular limitations, but in some embodiments, the total amount of "alkenyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) component may be in the range of 0.0003 moles or more and less than 0.0017 moles per 100 g of the silicone gum (G) component, and preferably in the range of 0.0004 moles or more and less than 0.0063 moles per 100 g of the silicone gum (G) component. If the total amount of "alkenyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" per 100g of the silicone gum (G) component is within the range described above, by adjusting the amount of the crosslinking agent described later, the addition reaction between the "hydrogen atoms bonded to silicon atoms" of the crosslinking agent and the "alkenyl groups bonded to silicon atoms" of the silicone gum (G1) component, and the dehydrogenation condensation reaction between the "hydrogen atoms bonded to silicon atoms" of the crosslinking agent and the "hydroxyl groups bonded to silicon atoms" of the silicone gum (G2) can be appropriately carried out. This makes it easy to set the compressive displacement (A) at 95°C, which is an indicator of the flexibility of the resulting adhesive layer and is determined by the TMA method of JIS K7196, to 60% or more of the thickness of the adhesive layer, and also provides appropriate adhesive properties for plastic lens molding.

[0084] ≪Component (3): Crosslinking Agent≫ The silicone adhesive composition used in the present invention includes component (1), which is the silicone gum (G), and component (2), which is the silicone resin (R), along with component (3), which is a crosslinking agent. The crosslinking agent is a component added to crosslink and cure the adhesive composition by an addition reaction with the "alkenyl group bonded to the silicon atom" and / or a dehydrogenation condensation reaction with the "hydroxyl group bonded to the silicon atom" of the silicone gum (G). Specifically in the present invention, an organopolysiloxane having three or more "hydrogen atoms bonded to the silicon atom" (hereinafter also simply referred to as "hydrosilyl group" or "Si-H group") in one molecule, so-called organohydrogenpolysiloxane, is used.

[0085] Examples of the crosslinking agent include, but are not limited to, organopolysiloxanes represented by the following general formula (4).

[0086]

[0087] (In the formula, R ５ Each of these is independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, R ６ Each of these is independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms or a hydrogen atom, where a is an integer from 0 to 100 and b is an integer from 3 to 80.

[0088] In the above formula (4), R ５ R is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms. ６ R is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms or a hydrogen atom. ５ , R ６ Examples of monovalent hydrocarbon groups include alkyl groups such as methyl, ethyl, propyl, and butyl groups; cycloalkyl groups such as cyclohexyl groups; alkenyl groups such as vinyl, allyl, hexenyl, and octenyl groups; aryl groups such as phenyl groups; and trifluoromethyl and 3,3,3-trifluoropropyl groups, in which some or all of the hydrogen atoms bonded to the carbon atoms of these groups are substituted with halogen atoms, etc. ５ , R６ Preferably, the group does not contain an aliphatic unsaturated bond, and is particularly preferably an aliphatic saturated hydrocarbon group or an aromatic hydrocarbon group, with methyl and phenyl groups being especially preferred.

[0089] In formula (4) above, a is an integer from 0 to 100, preferably from 0 to 80. Also, b is an integer from 3 to 80, preferably from 4 to 70.

[0090] The viscosity of the crosslinking agent at 25°C is preferably 1 to 5,000 mPa·s, and more preferably 5 to 500 mPa·s. The crosslinking agent can be used alone or in combination of two or more types.

[0091] The amount of crosslinking agent in the silicone adhesive composition can be appropriately adjusted according to the amount of functional groups in the silicone gum (G) component described above, so that the compressive displacement (A) of the resulting adhesive layer at 95°C, determined by the TMA method of JIS K7196, is 60% or more of the thickness of the adhesive layer. There are no particular limitations, but as a guideline, several embodiments are exemplified below.

[0092] In some preferred embodiments, when the total amount of "alkenyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) component is in the range of 0.0003 moles or more and less than 0.0004 moles per 100 g of the silicone gum (G), the amount of crosslinking agent blended is preferably such that the molar ratio of "hydrogen atoms bonded to silicon atoms" in the crosslinking agent component to the total amount of "alkenyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) component is, for example, 21.0 or more and less than 40.0, and more preferably 25.0 or more and less than 38.0.

[0093] Furthermore, in some more preferred embodiments, when the total amount of "alkenyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) component is in the range of 0.0004 moles or more and less than 0.00063 moles per 100 g of the silicone gum (G), the amount of crosslinking agent blended is preferably such that the molar ratio of "hydrogen atoms bonded to silicon atoms" in the crosslinking agent component to the total amount of "alkenyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) component is, for example, 3.0 or more and less than 21.0, and more preferably 12.0 or more and less than 17.0.

[0094] Furthermore, in some other embodiments, when the total amount of "alkenyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) component is in the range of 0.00063 moles or more and less than 0.0017 moles per 100 g of the silicone gum (G), the amount of crosslinking agent blended is preferably such that the molar ratio of "hydrogen atoms bonded to silicon atoms" in the crosslinking agent component to the total amount of "alkenyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) component is, for example, 0.2 or more and less than 3.0, and more preferably 0.3 or more and less than 2.8.

[0095] In each embodiment, if the molar ratio is within the range, the addition reaction between the "hydrogen atoms bonded to silicon atoms" of the crosslinking agent and the "alkenyl groups bonded to silicon atoms" of the silicone gum (G1) component, and the dehydrogenation condensation reaction between the "hydrogen atoms bonded to silicon atoms" of the crosslinking agent and the "hydroxyl groups bonded to silicon atoms" of the silicone gum (G2) can be carried out appropriately. This makes it easy to set the compressive displacement (A) at 95°C, which is an indicator of the flexibility of the resulting adhesive layer and is determined by the TMA method of JIS K7196, to 60% or more of the thickness of the adhesive layer, and also provides appropriate adhesive properties for plastic lens molding.

[0096] ≪Component (4): Platinum Group Metal Catalyst≫ The silicone adhesive composition used in the present invention includes component (1), which is the silicone gum (G), component (2), which is the silicone resin (R), component (3), which is the crosslinking agent, and component (4), which is a catalyst. Component (4), which is the catalyst, is a platinum group metal catalyst (hereinafter sometimes referred to as platinum group metal catalyst (E)) added to promote addition reactions and dehydrogenation condensation reactions between the "alkenyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone component (G) and the "hydrogen atoms bonded to silicon atoms" (Si-H groups) in the crosslinking agent component, thereby properly crosslinking and curing the silicone gum (G). Examples of the central metal of this catalyst include platinum group metals such as platinum, palladium, iridium, rhodium, osmium, and ruthenium, with platinum being preferred among these. Examples of platinum catalysts include chloroplatinic acid, alcoholic solutions of chloroplatinic acid, reaction products of chloroplatinic acid and alcohol, reaction products of chloroplatinic acid and olefin compounds, and reaction products of chloroplatinic acid and vinyl group-containing siloxanes.

[0097] The amount of the platinum group metal catalyst is preferably such that the metal mass is 0.1 to 1,000 ppm relative to the total mass of the silicone resin consisting of component (1), which is the silicone gum (G), and component (2), which is the silicone resin (R), and more preferably 1 to 500 ppm. If the amount is less than 1 ppm, the reaction is slow and curing is insufficient, which may reduce the holding power (cohesive force) of the resulting adhesive layer. If the amount exceeds 1,000 ppm, the resulting adhesive layer may have poor flexibility. In addition, the usable time of the adhesive composition solution during coating may be shortened. For silicone adhesives, catalysts such as the reaction product of chloroplatinic acid and vinyl group-containing siloxane are used. Effective catalysts for this adhesive are not particularly limited, but examples include CAT-PL-50T manufactured by Shin-Etsu Chemical Co., Ltd., and SRX-212Cat, NC-25, etc. (all are trade names) manufactured by Toray Dow Corning Co., Ltd.

[0098] (Tape Substrate) The material of the tape substrate is not particularly limited, but a material mainly composed of polyethylene terephthalate is optimal. However, the material of the tape substrate is not limited to polyethylene terephthalate, and other materials can also be used. Specific materials for tape substrate 2 include, for example, metal foils such as stainless steel and soft aluminum, and resin films such as polybutylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, biaxially oriented polypropylene, polyimide, aramid, polycycloolefin, and fluororesin. Furthermore, as a substrate with reduced water vapor permeability, composite films made by laminating aluminum foil and a resin film, films with a thin metal oxide film such as alumina or silicon dioxide formed on the surface of a resin film, and composite films made by laminating these with a resin film can also be used. The tape substrate may have an anchor treatment layer or the like on the side where the adhesive layer is provided to improve the adhesion between the adhesive layer and the substrate. The tape substrate may also have a back treatment layer on the side opposite to the side where the adhesive layer is provided.

[0099] For example, when polyethylene terephthalate is used as the material for the tape substrate, its thickness is preferably within the range of 20 μm to 75 μm. If it is less than 20 μm, the rigidity of the substrate 2 is low, and there is a risk that it will not be able to maintain the gap between the two molds 30, 30. In addition, it may not be able to withstand the force of expansion of the polymerizable monomer, causing cracking, cutting, etc., and there is a risk that air will enter the cavity C. On the other hand, if it exceeds 75 μm, the rigidity of the tape substrate is high, and there is a risk that its elasticity will decrease. In addition, gaps may occur in the wrap portion of the adhesive tape, and there is a risk that the resin (polymerizable monomer) may leak.

[0100] The holding force (drop time: minutes) of the adhesive layer of the adhesive tape of the present invention against a polished SUS304 steel plate (SUS304 plate polished in the same direction with #360 waterproof sandpaper) at 70°C is not particularly limited as long as the amount of compression displacement (A) at 95°C determined by the TMA method of JIS K7196 satisfies a predetermined range. However, in some embodiments, from the viewpoint of optimizing the cohesive force, it may be in the range of 50 minutes or more and less than 1440 minutes, and preferably in the range of 550 minutes or more and 1320 minutes or less. If the holding force at 70°C is less than 50 minutes, sufficient fixing force against the curing shrinkage of the monomer resin of the lens cannot be obtained, the mold follows and moves along the surface of the adhesive layer, and a shift in the distance between molds occurs, which may cause a change in the thickness of the lens after molding. On the other hand, if the holding force at 70°C exceeds 1440 minutes, the lens monomer's ability to follow thermal expansion is poor, causing gaps to form at the adhesive surface between the adhesive tape and the mold, and at the overlapping portions of the adhesive tapes, which can lead to resin leakage and, as a result, chipping or air bubbles in the lens. The holding force at 70°C is measured by the following method. First, a test piece measuring 25 mm wide x 150 mm long is taken from the prepared adhesive tape, and the adhesive layer of the test piece is attached to a polished SUS304 steel plate over an area of ​​25 mm x 25 mm. A 2000 g roller is then used to press it back and forth once at a speed of 5 mm / sec. After that, the sample is left at 70°C for 20 to 40 minutes and mounted on a test stand so that the test plate and test piece hang vertically. Next, a 9.8 N weight is attached to the end of the test piece, stored in a 70°C environment, and the time until the weight falls is measured. This fall time (in minutes) is taken as the value of the holding force.

[0101] In some embodiments, the adhesive layer of the adhesive tape of the present invention may have an adhesive strength to a polished SUS304 steel plate (a SUS304 steel plate polished in the same direction with #360 waterproof sandpaper) at 23°C, for example, in the range of 3.0 N / 10 mm to 6.0 N / 10 mm, preferably in the range of 3.5 N / 10 mm to 5.8 N / 10 mm. If the adhesive strength to the polished SUS304 steel plate at 23°C is less than 3.0 N / 10 mm, the adhesion between the adhesive tape and the mold will decrease, and the tape may peel off because it cannot keep up with the thermal response of the lens monomer. On the other hand, if the adhesive strength to the polished SUS304 steel plate at 23°C exceeds 6.0 N / 10 mm, the adhesion between the adhesive tape and the mold will increase, and there is a risk of adhesive residue being left on the mold when the adhesive tape is peeled off. The adhesive strength to the polished SUS304 steel plate at 23°C is measured by the following method. First, a test piece measuring 25 mm wide x 250 mm long is taken from the prepared adhesive tape. The adhesive layer of this test piece is attached to a polished SUS304 steel plate, and a 2000 g roller is used to press it back and forth once at a speed of 5 mm / sec. After that, the sample is left at 23°C for 20 to 40 minutes, and then the adhesive strength (unit: N / 10 mm) is measured by continuously peeling it off using a tensile testing apparatus at a peeling angle of 180° and a tensile speed of 5 mm / sec.

[0102] [Method for molding plastic lens products] Plastic lens products can be molded using adhesive tape like this.

[0103] (Cavity Forming Process) First, a pair of molds made of glass, for example, roughly disc-shaped, are placed facing each other at a predetermined distance (a distance equal to the thickness of the plastic lens molded product). Then, adhesive tape is attached to the outer surfaces of the pair of glass molds by wrapping it around them in the circumferential direction. As a result, the pair of molds seal the space formed between them while maintaining the above distance. In this way, the molds are connected in roughly parallel positions, and a flat or cylindrical cavity is partitioned between them, creating a polymerization cell.

[0104] (Monomer Filling Process) Then, one end of the adhesive tape is peeled off to create a gap in the cavity of the polymerization cell, and a nozzle is inserted into the cavity through this gap. After injecting the polymerizable monomer into the cavity through the nozzle and filling it, the gap is then sealed again with adhesive tape. Here, the polymerizable monomer used is a mixture of m-xylylene diisocyanate and pentaerythritol tetrakis mercaptopropionate, or a mixture of m-xylylene diisocyanate and bis(mercaptoethyl) trithioglycerin, but is not limited to these.

[0105] (Polymerization process) The resin in the cavity is then heated to induce a polymerization reaction and harden. After the polymerization process has sufficiently hardened the polymerizable monomers, all the adhesive tape is removed and the mold is taken off. In this way, a plastic lens molded product is obtained.

[0106] (Mold) In this invention, a disc-shaped glass (silicon dioxide) mold is used, in which opposing surfaces are formed on both sides of the plastic lens to have a desired curvature. In addition, molds made of metal or other materials may also be used.

[0107] (Polymerizable monomers) The polymerizable monomers used as raw materials for plastic lenses are not particularly limited, but in the case of lenses, conventionally known materials are used. For example, when obtaining eyeglass lenses with an ultra-high refractive index (refractive index Ne: ≥ 1.65), monomers of episulfide resins (MR-174 manufactured by Mitsui Chemicals, Inc., IU-20 manufactured by Mitsubishi Gas Chemical Company, Inc.) or thiourethane resins (MR-7 manufactured by Mitsui Chemicals, Inc.) are used.

[0108] Furthermore, when obtaining eyeglass lenses with a high refractive index (1.58 ≤ Ne < 1.65), monomers such as thiourethane resins (MR-6 and MR-8 manufactured by Mitsui Chemicals), polyester methacrylate (TS-26 manufactured by Tokuyama Corporation), and polycarbonate (Panlite manufactured by Teijin Chemicals) are used. Furthermore, when obtaining eyeglass lenses with a medium refractive index (1.55 ≤ Ne < 1.58), monomers such as urethane methacrylate (K-23 manufactured by Kureha Corporation), epoxy methacrylate (MCR-50 manufactured by Mitsubishi Rayon Corporation), diallyl carbonate (HIRI manufactured by PPG Industries), and diallyl phthalate resins (NK-55 manufactured by NOF Corporation) are used.

[0109] Furthermore, when obtaining spectacle lenses with a low refractive index (Ne: < 1.55), monomers such as urethane resin (TRIVEX manufactured by PPG Industries), urethane methacrylate (MCR-10 manufactured by Mitsubishi Rayon Co., Ltd.), methacrylate (K-55 manufactured by Kureha Corporation), allyl diglycol carbonate (CR-39 manufactured by PPG Industries), diallyl carbonate (CR-607 manufactured by PPG Industries), and polymethyl methacrylate (polymethyl methacrylate) can be used.

[0110] The adhesive tape for molding plastic lenses of the present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The amounts of materials used in the examples are expressed on a solid content (non-volatile component) mass basis.

[0111] <Materials> The adhesive tapes of the examples and comparative examples were manufactured using the materials shown in Table 1, according to a standard method for manufacturing adhesive tapes.

[0112]

[0113] <Example 1> A toluene solution of a silicone resin was prepared by blending a silicone gum (G1) having alkenyl groups (vinyl groups) in a solid content of 20.0 parts by mass, a silicone gum (G2) having silanol groups in a solid content of 3.8 parts by mass, a non-functional silicone gum (G3) in a solid content of 5.7 parts by mass, and a silicone resin (R) in a solid content of 70.5 parts by mass. A crosslinking agent was added to this solution in a solid content of 0.16 parts by mass, and a reaction control agent in a non-volatile content of 0.085 parts by mass, and the mixture was stirred and mixed. The solution was then diluted with toluene to obtain a resin composition solution adjusted to a solid content concentration of 40% by mass of the silicone resin component. A platinum group metal catalyst was further added to the obtained resin composition in an amount such that the amount of platinum metal relative to the silicone resin component was 26 ppm, and the mixture was uniformly stirred and mixed to prepare a silicone adhesive composition solution. A solution of this adhesive composition was applied to the PET film side of a PET composite substrate with a thickness of 23 μm so that the adhesive layer thickness was 26 μm. The adhesive tape was then dried and cured by heat treatment (dry treatment) at a maximum temperature of 180°C to produce an adhesive tape with a total thickness of 64 μm. An anchor treatment layer containing a condensation-polymerizable silicone resin was provided between the adhesive layer and the PET composite substrate, and a back treatment layer containing a long-chain alkyl resin was provided on the back side of the PET composite substrate. In the adhesive composition of Example 1, the amount of "vinyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000481 mol / 100g, and the amount of "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000045 mol / 100g, for a total of 0.000526 mol / 100g. Furthermore, the molar ratio [Si-H] / ([Vi]+[Si-OH]) of hydrogen atoms bonded to silicon atoms in the crosslinking agent to the total amount of vinyl groups bonded to silicon atoms and hydroxyl groups bonded to silicon atoms in the silicone gum (G) was 16.1. In addition, the holding force against polished SUS304 steel plate at 70°C was measured to be 1,214 minutes. Furthermore, the adhesive force against polished SUS304 steel plate at 23°C was measured to be 5.6 N / 10 mm.

[0114] <Example 2> An adhesive tape was prepared in the same manner as in Example 1, except that the toluene solution of the silicone resin was changed to a toluene solution of silicone resin formulated with 20.0 parts by mass of alkenyl group-containing silicone gum (G1), 6.0 parts by mass of silanol group-containing silicone gum (G2), 5.7 parts by mass of non-functional silicone gum (G3), and 68.3 parts by mass of silicone resin (R) as solids. In the adhesive composition of Example 2, the amount of "vinyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000448 mol / 100g, and the amount of "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000066 mol / 100g, for a total of 0.000514 mol / 100g. Furthermore, the molar ratio [Si-H] / ([Vi]+[Si-OH]) of hydrogen atoms bonded to silicon atoms in the crosslinking agent to the total amount of vinyl groups bonded to silicon atoms and hydroxyl groups bonded to silicon atoms in the silicone gum (G) was 15.3. The holding force against polished SUS304 steel plate at 70°C was measured to be 1,150 minutes. Additionally, the adhesive strength against polished SUS304 steel plate at 23°C was measured to be 5.5 N / 10 mm.

[0115] <Example 3> An adhesive tape was prepared in the same manner as in Example 1, except that the amount of crosslinking agent in the resin composition was changed to 0.13 parts by mass in terms of solid content. In the adhesive composition of Example 3, the amount of "vinyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000481 mol / 100g, and the amount of "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000045 mol / 100g, for a total of 0.000526 mol / 100g. Furthermore, the molar ratio of "hydrogen atoms bonded to silicon atoms" in the crosslinking agent to the total amount of "vinyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) [Si-H] / ([Vi] + [Si-OH]) was 13.0. In addition, the holding force against a polished SUS304 steel plate at 70°C was measured to be 859 minutes. Furthermore, when the adhesive strength to a polished SUS304 steel plate was measured at 23°C, it was found to be 3.5 N / 10 mm.

[0116] <Example 4> An adhesive tape was prepared in the same manner as in Example 1, except that the amount of crosslinking agent in the resin composition was changed to 0.20 parts by mass in terms of solid content. The amount of "vinyl groups bonded to silicon atoms" in the silicone gum (G) of the adhesive composition of Example 1 was 0.000481 mol / 100g, and the amount of "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000045 mol / 100g, for a total of 0.000526 mol / 100g. Furthermore, the molar ratio of "hydrogen atoms bonded to silicon atoms" in the crosslinking agent to the total amount of "vinyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) [Si-H] / ([Vi] + [Si-OH]) was 20.1.

[0117] <Example 5> A toluene solution was prepared by blending 19.6 parts by mass of a silicone gum having an alkenyl group (G1) with solid content, 9.7 parts by mass of a silicone gum having a silanol group (G2) with solid content, and 70.7 parts by mass of silicone resin (R) with solid content. A crosslinking agent was added to this solution in an amount of 0.16 parts by mass with solid content and a reaction control agent in an amount of 0.085 parts by mass with non-volatile content. The mixture was stirred and mixed, and then diluted with toluene to obtain a resin composition solution adjusted to have a solid content concentration of 40% by mass of the silicone resin component. A platinum group metal catalyst was further added to the obtained resin composition in an amount such that the amount of platinum metal relative to the silicone resin component was 26 ppm. The mixture was then uniformly stirred and mixed to prepare a silicone adhesive composition solution. A solution of this adhesive composition was applied to the PET film side of a PET composite substrate with a thickness of 23 μm so that the adhesive layer thickness was 34 μm. The maximum heat treatment (drying) temperature was set to 180°C, and the tape was dried and cured to produce an adhesive tape with a total thickness of 72 μm. In the adhesive composition of Example 5, the amount of "vinyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000475 mol / 100g, and the amount of "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000116 mol / 100g, for a total of 0.000591 mol / 100g. Furthermore, the molar ratio of "hydrogen atoms bonded to silicon atoms" in the crosslinking agent to the total amount of "vinyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) [Si-H] / ([Vi] + [Si-OH]) was 14.4.

[0118] <Example 6> An adhesive tape was prepared in the same manner as in Example 5, except that the toluene solution of the silicone resin was changed to a toluene solution containing 20.0 parts by mass of alkenyl group-containing silicone gum (G1), 9.5 parts by mass of non-functional silicone gum (G3), and 70.5 parts by mass of silicone resin (R). In the adhesive composition of Example 6, the amount of "vinyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000481 mol / 100g, and the amount of "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) was 0 mol / 100g, for a total of 0.000481 mol / 100g. Furthermore, the molar ratio of "hydrogen atoms bonded to silicon atoms" in the crosslinking agent to the total amount of "vinyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) [Si-H] / ([Vi] + [Si-OH]) was 17.6.

[0119] <Example 7> An adhesive tape was prepared in the same manner as in Example 5, except that the toluene solution of the silicone resin was changed to a toluene solution formulated with 18.4 parts by mass of solids of a silicone gum (G1) having alkenyl groups, 9.1 parts by mass of solids of a silicone gum (G2) having silanol groups, 6.0 parts by mass of solids of a non-functional silicone gum (G3), and 66.5 parts by mass of solids of silicone resin (R), and the amount of crosslinking agent in the resin composition was changed to 0.15 parts by mass of solids. In the adhesive composition of Example 7, the amount of "vinyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000390 mol / 100g, the amount of "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000095 mol / 100g, and the total amount was 0.000485 mol / 100g. Furthermore, the molar ratio [Si-H] / ([Vi]+[Si-OH]) of hydrogen atoms bonded to silicon atoms in the crosslinking agent to the total amount of vinyl groups bonded to silicon atoms and hydroxyl groups bonded to silicon atoms in the silicone gum (G) was 14.4.

[0120] <Example 8> An adhesive tape was prepared in the same manner as in Example 5, except that the toluene solution of the silicone resin was changed to a toluene solution containing 19.0 parts by mass of silanol group-containing silicone gum (G2) and 81.0 parts by mass of silicone resin (R) in terms of solid content. In the adhesive composition of Example 8, the amount of "vinyl groups bonded to silicon atoms" in the silicone gum (G) was 0 mol / 100g, and the amount of "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000350 mol / 100g, for a total of 0.000350 mol / 100g. Furthermore, the molar ratio of "hydrogen atoms bonded to silicon atoms" in the crosslinking agent to the total amount of "vinyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) [Si-H] / ([Vi] + [Si-OH]) was 37.5.

[0121] <Example 9> An adhesive tape was prepared in the same manner as in Example 5, except that the toluene solution of the silicone resin was changed to a toluene solution containing 15.6 parts by mass of a silicone gum (G1) having an alkenyl group, 11.6 parts by mass of a silicone gum (G2) having a silanol group, and 72.8 parts by mass of silicone resin (R) in solid content. In the adhesive composition of Example 9, the amount of "vinyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000407 mol / 100g, and the amount of "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000149 mol / 100g, for a total of 0.000557 mol / 100g. Furthermore, the molar ratio [Si-H] / ([Vi]+[Si-OH]) of hydrogen atoms bonded to silicon atoms in the crosslinking agent to the total amount of vinyl groups bonded to silicon atoms and hydroxyl groups bonded to silicon atoms in the silicone gum (G) was 16.5.

[0122] <Example 10> An adhesive tape was prepared in the same manner as in Example 1, except that the adhesive layer thickness was 42 μm when the adhesive was applied to the PET film side of a PET composite substrate with a thickness of 23 μm. In the adhesive composition of Example 10, the amount of "vinyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000481 mol / 100g, and the amount of "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000045 mol / 100g, for a total of 0.000526 mol / 100g. Furthermore, the molar ratio of "hydrogen atoms bonded to silicon atoms" in the crosslinking agent to the total amount of "vinyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) [Si-H] / ([Vi] + [Si-OH]) was 16.1.

[0123] <Example 11> An adhesive tape was prepared in the same manner as in Example 5, except that the toluene solution of the silicone resin was changed to a toluene solution formulated with 20.0 parts by mass of solids of a silicone gum having alkenyl groups (G1), 3.8 parts by mass of solids of a silicone gum having silanol groups (G2), 5.7 parts by mass of solids of a non-functional silicone gum (G3), and 70.5 parts by mass of solids of silicone resin (R), and the amount of crosslinking agent in the resin composition was changed to 0.035 parts by mass of solids. In the adhesive composition of Example 11, the amount of "vinyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000481 mol / 100g, the amount of "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000045 mol / 100g, and the total amount was 0.000526 mol / 100g. Furthermore, the molar ratio [Si-H] / ([Vi]+[Si-OH]) of hydrogen atoms bonded to silicon atoms in the crosslinking agent to the total amount of vinyl groups bonded to silicon atoms and hydroxyl groups bonded to silicon atoms in the silicone gum (G) was 3.5.

[0124] <Example 12> An adhesive tape was prepared in the same manner as in Example 1, except that the toluene solution of the silicone resin was changed to a toluene solution containing 34.0 parts by mass of alkenyl group-containing silicone gum (G1), 2.9 parts by mass of non-functional silicone gum (G3), and 63.1 parts by mass of silicone resin (R) in terms of solid content, and the amount of crosslinking agent in the resin composition was changed to 0.03 parts by mass in terms of solid content. In the adhesive composition of Example 12, the amount of "vinyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000655 mol / 100g, and the amount of "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) was 0 mol / 100g, for a total of 0.000655 mol / 100g. Furthermore, the molar ratio [Si-H] / ([Vi]+[Si-OH]) of hydrogen atoms bonded to silicon atoms in the crosslinking agent to the total amount of vinyl groups bonded to silicon atoms and hydroxyl groups bonded to silicon atoms in the silicone gum (G) was 1.9. In addition, the holding force against polished SUS304 steel plate at 70°C was measured to be 73 minutes. Furthermore, the adhesive strength against polished SUS304 steel plate at 23°C was measured to be 5.0 N / 10 mm.

[0125] <Comparative Example 1> An adhesive tape was prepared in the same manner as in Example 11, except that the amount of crosslinking agent in the resin composition was changed to 0.32 parts by mass in terms of solid content. In the adhesive composition of Comparative Example 1, the amount of "vinyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000481 mol / 100g, and the amount of "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000045 mol / 100g, for a total of 0.000526 mol / 100g. Furthermore, the molar ratio of "hydrogen atoms bonded to silicon atoms" in the crosslinking agent to the total amount of "vinyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) [Si-H] / ([Vi] + [Si-OH]) was 32.1. In addition, when the holding force against a polished SUS304 steel plate at 70°C was measured, it did not fall off after 24 hours. Furthermore, when the adhesive strength to a polished SUS304 steel plate was measured at 23°C, it was found to be 5.7 N / 10 mm.

[0126] <Comparative Example 2> An adhesive tape was prepared in the same manner as in Example 12, except that the amount of crosslinking agent in the resin composition was changed to 0.05 parts by mass in terms of solid content. In the adhesive composition of Comparative Example 2, the amount of "vinyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000655 mol / 100g, and the amount of "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) was 0 mol / 100g, for a total of 0.000655 mol / 100g. Furthermore, the molar ratio of "hydrogen atoms bonded to silicon atoms" in the crosslinking agent to the total amount of "vinyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) [Si-H] / ([Vi] + [Si-OH]) was 3.2. In addition, the holding force against a polished SUS304 steel plate at 70°C was measured to be 112 minutes. Furthermore, when the adhesive strength to a polished SUS304 steel plate was measured at 23°C, it was found to be 5.6 N / 10 mm.

[0127] <Comparative Example 3> An adhesive tape was prepared in the same manner as in Example 12, except that the amount of crosslinking agent in the resin composition was changed to 0.06 parts by mass in terms of solid content. In the adhesive composition of Comparative Example 3, the amount of "vinyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000655 mol / 100g, and the amount of "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) was 0 mol / 100g, for a total of 0.000655 mol / 100g. Furthermore, the molar ratio of "hydrogen atoms bonded to silicon atoms" in the crosslinking agent to the total amount of "vinyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) [Si-H] / ([Vi] + [Si-OH]) was 3.9. In addition, the holding force against a polished SUS304 steel plate at 70°C was measured to be 531 minutes. Furthermore, when the adhesive strength to a polished SUS304 steel plate was measured at 23°C, it was found to be 5.9 N / 10 mm.

[0128] <Comparative Example 4> An adhesive tape was prepared in the same manner as in Example 5, except that the toluene solution of the silicone resin was changed to a toluene solution containing 40.0 parts by mass of a silicone gum (G1) having alkenyl groups and 60.0 parts by mass of silicone resin (R) in terms of solid content. In the adhesive composition of Comparative Example 4, the amount of "vinyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000710 mol / 100g, and the amount of "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) was 0 mol / 100g, for a total of 0.000710 mol / 100g. Furthermore, the molar ratio [Si-H] / ([Vi]+[Si-OH]) of "hydrogen atoms bonded to silicon atoms" in the crosslinking agent to the total amount of "vinyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) was 8.8.

[0129] <Comparative Example 5> An adhesive tape was prepared in the same manner as in Example 5, except that the toluene solution of the silicone resin was changed to a toluene solution formulated with 28.0 parts by mass of alkenyl group-containing silicone gum (G1), 5.7 parts by mass of silicone gum (G3), and 66.3 parts by mass of silicone resin (R). In the adhesive composition of Comparative Example 5, the amount of "vinyl groups bonded to silicon atoms" in the silicone gum (G) was 0.000590 mol / 100g, and the amount of "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) was 0 mol / 100g, for a total of 0.000590 mol / 100g. Furthermore, the molar ratio [Si-H] / ([Vi]+[Si-OH]) of "hydrogen atoms bonded to silicon atoms" in the crosslinking agent to the total amount of "vinyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) was 12.5.

[0130] The compressive displacement (A) of the adhesive tapes in the examples and comparative examples was determined using the following measurement conditions and methods.

[0131] <Compressive Displacement (A)> First, a sample measuring 0.5 cm x 0.5 cm was taken from the prepared adhesive tape. Next, the sample was placed in a thermomechanical analyzer (TMA) and the probe, which is connected to the displacement detection unit and the load generation unit, was brought into contact with the surface of the adhesive layer of the sample. Subsequently, the sample was cooled to -80°C using liquid nitrogen, and then heated to 150°C at a predetermined heating rate while applying a load to the adhesive layer of the sample from the load generation unit via the probe, to obtain a temperature-displacement (length) curve. From the obtained temperature-displacement curve, the displacement at 95°C (unit: μm) was read, and this value was converted to a ratio to the thickness of the adhesive layer to obtain the compressive displacement (A) of the adhesive layer of the sample at 95°C (unit: %).

[0132] <Analysis Conditions> Instrument Name: Rigaku Corporation, product name "Thermo Plus EVO2" Test Mode: Compression method, adhesive layer on the probe side Sample Size: 0.5 cm square Atmosphere: Nitrogen Load: 10 g (98 mN) Probe Diameter: 1 mmφ Measurement Temperature Range: -60°C ± 20°C to 150°C Heating Rate: 10°C / min

[0133] <Bubble Prevention Properties> The adhesive tapes of the examples and comparative examples were cut to a predetermined width and attached to the outer surface of a pair of glass molds along the circumferential direction to create polymerization cells. Next, as described above, polymerizable monomers (refractive index of 1.60 when homopolymerized) were injected and filled into the cavities, and polymerization was carried out by a predetermined temperature curing process to mold plastic lenses (refractive index of 1.60). The bubble prevention properties of the adhesive tapes were evaluated by visually observing the state of bubbles in the obtained plastic lenses.

[0134] Regarding bubble prevention, the outer surface of the obtained plastic lenses was visually inspected, and the presence and number of bubbles were measured. The diameter of the bubbles was also measured using a microscope. The evaluation criteria for bubble prevention are shown below.

[0135] (Bubble Prevention Evaluation Criteria) A (Excellent): No bubbles B (Good): 1 to 5 bubbles with a diameter of 1.0 mm or less C (Poor): 6 or more bubbles with a diameter of 1.0 mm or less, or bubbles with a diameter greater than 1.0 mm

[0136] Tables 1 to 3 show the composition of the adhesive layer of the adhesive tapes in Examples 1 to 12 and Comparative Examples 1 to 5, as well as the test results.

[0137]

[0138]

[0139]

[0140] As shown in Tables 1 and 2, when the adhesive tapes of Examples 1 to 12, which satisfy the requirements of the present invention, were applied as adhesive tapes for plastic molding, it was found that the generation of minute air bubbles on the outer surface of the molded plastic lens was sufficiently suppressed. In contrast, the adhesive tapes of Comparative Examples 1 to 5, which do not satisfy the requirements of the present invention, showed clearly inferior air bubble prevention performance on the outer surface of the molded plastic lens compared to the adhesive tapes of the Examples.

Claims

1. A plastic lens molding adhesive tape comprising a strip-shaped substrate and an adhesive layer formed on one surface of the substrate, wherein the adhesive comprises a silicone resin mixed with (1) a silicone gum (G) selected from the group consisting of (1) a silicone gum (G1) having an alkenyl group bonded to a silicon atom and a silicone gum (G2) having a hydroxyl group bonded to a silicon atom, and (2) a silicone resin (R) as a base polymer, and further comprising (3) an organopolysiloxane having three or more hydrogen atoms bonded to a silicon atom in one molecule as a crosslinking agent, and (4) a cured product layer comprising a cured product of a silicone adhesive composition containing a platinum group metal catalyst as a crosslinking reaction catalyst, wherein the adhesive layer has a compressive displacement (A) at 95°C determined by the TMA method of JIS K7196 which is 60% or more of the thickness of the adhesive layer.

2. The adhesive tape for molding plastic lenses according to claim 1, wherein the mass ratio G / R of the silicone gum (G) to the silicone resin (R) is 15.0 / 85.0 to 37.0 / 63.

0.

3. The adhesive tape for molding plastics according to claim 1 or 2, wherein the total amount of "alkenyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) is in the range of 0.0003 moles or more and less than 0.0004 moles per 100 g of the silicone gum (G), and the amount of the crosslinking agent blended is such that the molar ratio of "hydrogen atoms bonded to silicon atoms" in the crosslinking agent to the total amount of "alkenyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) is 21.0 or more and less than 40.

0.

4. The adhesive tape for molding plastics according to claim 1 or 2, wherein the total amount of "alkenyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) is in the range of 0.0004 moles or more and less than 0.00063 moles per 100 g of the silicone gum (G), and the amount of the crosslinking agent blended is such that the molar ratio of "hydrogen atoms bonded to silicon atoms" in the crosslinking agent to the total amount of "alkenyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) is 3.0 or more and less than 21.

0.

5. The adhesive tape for molding plastics according to claim 1 or 2, wherein the total amount of "alkenyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) is in the range of 0.00063 moles or more and less than 0.0017 moles per 100 g of the silicone gum (G), and the amount of the crosslinking agent blended is such that the molar ratio of "hydrogen atoms bonded to silicon atoms" in the crosslinking agent to the total amount of "alkenyl groups bonded to silicon atoms" and "hydroxyl groups bonded to silicon atoms" in the silicone gum (G) is 0.2 or more and less than 3.

0.

6. The adhesive tape for molding plastic lenses according to any one of claims 1 to 5, wherein the silicone gum (G) comprises a silicone gum (G1) having an alkenyl group bonded to a silicon atom and a silicone gum (G2) having a hydroxyl group bonded to a silicon atom.

7. The adhesive tape for molding plastic lenses according to any one of claims 1 to 6, wherein the adhesive layer has a thickness of 10 to 50 μm.

8. The adhesive tape for molding plastic lenses according to any one of claims 1 to 7, wherein the 70°C holding force to polished SUS304 steel plate is 50 minutes or more and less than 1,440 minutes, and the adhesive force to polished SUS304 steel plate is 3.0 N / 10 mm or more and 6.0 N / 10 mm or less.

9. A method for manufacturing a plastic lens molded product, comprising arranging a pair of molds at a predetermined distance apart, forming a cavity between the pair of molds by attaching one of the adhesive tapes for molding plastic lenses from claims 1 to 8 to the outer circumferential surfaces of the pair of molds, filling the cavity with a polymerizable monomer, and polymerizing the polymerizable monomer.

10. A molded article manufactured using the adhesive tape for molding plastic lenses described in any one of claims 1 to 8.

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