High-temperature and high-humidity resistant OCA optical adhesive, its preparation method and application

Abstract

The present invention relates to the technical field of optical adhesives, and particularly relates to a high-temperature and high-humidity resistant OCA optical adhesive, its preparation method and application. The high-temperature and high-humidity resistant OCA optical adhesive comprises 40-55 parts of soft monomer, 10-25 parts of hard monomer, 5-20 parts of functional monomer, 5-15 parts of thiourea monomer, 3-15 parts of polyurethane acrylate prepolymer, 0.2-2 parts of photoinitiator, 0.05-2 parts of chain transfer agent, 0.1-1 part of tackifying coupling agent, 0.1-1.5 parts of antioxidant, 0.05-1 part of leveling agent and 0.05-1.5 parts of crosslinking agent; the polyurethane acrylate prepolymer is mainly prepared by reacting a polyol, a polyisocyanate and a hydroxyl-containing acrylate. The OCA optical adhesive of the present invention not only has the characteristic of high light transmittance, but also can maintain good adhesion, stability and durability in an extreme environment of high temperature and high humidity.

Description

Technical Field

[0001] The present invention relates to the technical field of optical adhesives, and particularly relates to a high-temperature and high-humidity resistant OCA optical adhesive, a preparation method thereof, and an application thereof. Background Art

[0002] With the continuous development of technology, the popularization and diversified applications of electronic products have put forward higher requirements for material properties. As a key material, OCA optical adhesives are widely used in the display screens of various products such as smart phones, tablet computers, electronic watches, and automobiles. With the increasing importance of various devices in daily life and the increasingly complex usage environments, many devices need to operate under high-temperature and high-humidity conditions. Therefore, the market's demand for the optical properties, adhesion, and durability of OCA optical adhesives under extreme environments such as high temperature and high humidity is increasing. Traditional optical adhesives are prone to problems such as yellowing, foaming, or delamination under such extreme environments, affecting the display effect and the service life of the device. In addition, traditional optical adhesives may contain volatile organic compounds (VOCs) and other harmful substances, which not only pollute the environment but also pose a potential threat to human health. Therefore, the development of an environmentally friendly OCA optical adhesive that can still maintain excellent performance under high-temperature and high-humidity conditions has become an urgent need in the industry.

[0003] In view of this, the present invention is specifically proposed. Summary of the Invention

[0004] The object of the present invention is to provide a high-temperature and high-humidity resistant OCA optical adhesive, a preparation method thereof, and an application thereof. The OCA optical adhesive of the present invention has excellent high-temperature and high-humidity resistance, and still maintains good optical properties, bonding properties, and aging resistance under high-temperature and high-humidity conditions.

[0005] To achieve the above object of the present invention, in the first aspect of the present invention, a high-temperature and high-humidity resistant OCA optical adhesive is provided, which comprises the following components in parts by weight: 40 - 55 parts of a soft monomer, 10 - 25 parts of a hard monomer, 5 - 20 parts of a functional monomer, 5 - 15 parts of a thiourea monomer, 3 - 15 parts of a polyurethane acrylate prepolymer, 0.2 - 2 parts of a photoinitiator, 0.05 - 2 parts of a chain transfer agent, 0.1 - 1 part of a tackifying coupling agent, 0.1 - 1.5 parts of an antioxidant, 0.05 - 1 part of a leveling agent, and 0.05 - 1.5 parts of a crosslinking agent;

[0006] The polyurethane acrylate prepolymer is mainly prepared by reacting a polyol, a polyisocyanate, and a hydroxyl-containing acrylate; the polyol includes polytetrahydrofuran ether diol and polycaprolactone diol, and the polyisocyanate includes isophorone diisocyanate and hexamethylene diisocyanate.

[0007] In a specific embodiment of the present invention, in the polyol, the molar ratio of the polytetrahydrofuran ether diol to the polycaprolactone diol is 1:(0.5 - 2).

[0008] In a specific embodiment of the present invention, in the polyisocyanate, the molar ratio of isophorone diisocyanate to hexamethylene diisocyanate is 1:(0.5 - 2).

[0009] In a specific embodiment of the present invention, the molar ratio of the polyol to the polyisocyanate is 1:(1.2 - 1.5).

[0010] In a specific embodiment of the present invention, the molar ratio of the polyol to the hydroxyl-containing acrylate is 1:(0.8 - 1.2). Further, the hydroxyl-containing acrylate includes at least one of 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, and hydroxypropyl acrylate.

[0011] In a specific embodiment of the present invention, the preparation of the polyurethane acrylate prepolymer is carried out under the action of a catalyst. Further, the catalyst includes at least one of dibutyltin dilaurate, triethylenediamine, and stannous octoate.

[0012] In a specific embodiment of the present invention, in the preparation of the polyurethane acrylate prepolymer, the raw materials further include a chain extender and / or a filler.

[0013] In a specific embodiment of the present invention, the dosage of the chain extender is 0.5 wt% - 2 wt% of the total amount of the polyol, the polyisocyanate, and the hydroxyl-containing acrylate. Further, the chain extender is 1,4-butanediol and / or 1,6-hexanediol.

[0014] In a specific embodiment of the present invention, the dosage of the filler is 8 wt% - 12 wt% of the total amount of the polyol, the polyisocyanate, and the hydroxyl-containing acrylate. Further, the filler includes at least one of nanocellulose, nanoaluminum oxide, and nanosilica; the particle size of the filler is 1 - 50 nm.

[0015] In a specific embodiment of the present invention, the thiourea monomer includes at least one of 1,3-diallyl 2-thiourea, allyl thiourea, 1-allyl-3-(4-benzylphenyl)thiourea, 1-allyl-3-(pyridin-3-yl)thiourea, 1-allyl-3,3-diethyl-2-thiourea, 1-methallyl-3-methyl-2-thiourea, and N-allyl N'-2-hydroxyethyl thiourea.

[0016] In a specific embodiment of the present invention, the mass ratio of the thiourea monomer to the polyurethane acrylate prepolymer is (0.5 - 3):1.

[0017] In a specific embodiment of the present invention, the glass transition temperature of the soft monomer is -60 to -10 °C. Further, the soft monomer includes at least one of ethyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, butyl acrylate, and isooctyl acrylate.

[0018] In a specific embodiment of the present invention, the hard monomer includes at least one of methyl acrylate, methyl methacrylate, isobornyl acrylate, ethyl methacrylate, styrene, and acrylonitrile.

[0019] In a specific embodiment of the present invention, the functional monomer includes at least one of acrylic acid, acrylamide, N,N-dimethylacrylamide, 2-hydroxyethyl acrylate, and 2-hydroxybutyl acrylate.

[0020] In a specific embodiment of the present invention, the crosslinking agent includes at least one of diethylene glycol diacrylate, triethylene glycol diacrylate, pentaerythritol triacrylate, and trimethylolpropane triacrylate.

[0021] The second aspect of the present invention provides a preparation method of the high-temperature and high-humidity resistant OCA optical adhesive provided by the first aspect of the present invention, including the following steps: After uniformly mixing the soft monomer, hard monomer, functional monomer, thiourea monomer, polyurethane acrylate prepolymer, and photoinitiator, irradiate with ultraviolet light for 3 to 5 minutes, then add a chain transfer agent, a tackifying coupling agent, an antioxidant, a leveling agent, and a crosslinking agent and mix uniformly, and cure by ultraviolet light irradiation after coating.

[0022] In a specific embodiment of the present invention, the thickness of the OCA optical adhesive is 50 to 300 μm.

[0023] The third aspect of the present invention provides an application of the high-temperature and high-humidity resistant OCA optical adhesive provided by the first aspect of the present invention in a display screen.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] (1) The OCA optical adhesive of the present invention not only has the characteristic of high light transmittance, but also can maintain good adhesiveness, stability, and durability in an extreme environment of high temperature and high humidity, can prevent blistering or delamination caused by water vapor penetration, and is not prone to deformation or failure;

[0026] (2) The preparation process of the OCA optical adhesive of the present invention does not require the use of organic solvents, and the preparation method is simple, meeting the dual requirements of high performance and environmental protection requirements. Specific Embodiments

[0027] The technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. However, those skilled in the art will understand that the following described embodiments are some embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be construed as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention. For those conditions not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or instruments not specified by the manufacturer can be obtained as conventional products through commercial purchase.

[0028] In the first aspect of the present invention, a high-temperature and high-humidity resistant OCA optical adhesive is provided, which comprises the following components in parts by weight: 40-55 parts of soft monomer, 10-25 parts of hard monomer, 5-20 parts of functional monomer, 5-15 parts of thiourea monomer, 3-15 parts of polyurethane acrylate prepolymer, 0.2-2 parts of photoinitiator, 0.05-2 parts of chain transfer agent, 0.1-1 part of tackifying coupling agent, 0.1-1.5 parts of antioxidant, 0.05-1 part of leveling agent and 0.05-1.5 parts of crosslinking agent.

[0029] The polyurethane acrylate prepolymer is mainly prepared by reacting a polyol, a polyisocyanate and a hydroxyl-containing acrylate; the polyol includes polytetrahydrofuran ether diol and polycaprolactone diol, and the polyisocyanate includes isophorone diisocyanate and hexamethylene diisocyanate.

[0030] The OCA optical adhesive of the present invention not only has the characteristic of high light transmittance, but also can maintain good adhesion, stability and durability in extreme environments of high temperature and high humidity, can prevent blistering or delamination caused by water vapor penetration, and is not prone to deformation or failure.

[0031] A certain amount of thiourea monomer and polyurethane acrylate prepolymer are introduced into the OCA optical adhesive of the present invention. The addition of the polyurethane acrylate prepolymer introduces polyurethane segments with excellent thermal stability and hydrolysis resistance in the OCA optical adhesive system, and the acrylate segments polymerize with various monomers to form a crosslinked network structure. Coupled with the more hydrophobic groups and intermolecular hydrogen bond interactions introduced by the thiourea monomer, while taking into account the high light transmittance of the OCA optical adhesive, the high-temperature and high-humidity resistance of the OCA optical adhesive is significantly improved.

[0032] On the basis of adopting the above components, the present invention adjusts the ratio to balance and ensure the high light transmittance and high-temperature and high-humidity resistance of the OCA optical adhesive. For example, in different embodiments, in the high-temperature and high-humidity resistant OCA optical adhesive, the amounts of each component in parts by weight can be as follows:

[0033] The dosage of the soft monomer can be 40 parts, 42 parts, 45 parts, 48 parts, 50 parts, 52 parts, 55 parts or the range composed of any two of them;

[0034] The dosage of the hard monomer can be 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts or the range composed of any two of them;

[0035] The dosage of the functional monomer can be 5 parts, 8 parts, 10 parts, 12 parts, 15 parts, 18 parts, 20 parts or the range composed of any two of them;

[0036] The dosage of the thiourea monomer can be 5 parts, 8 parts, 10 parts, 12 parts, 15 parts or the range composed of any two of them;

[0037] The dosage of the polyurethane acrylate prepolymer can be 3 parts, 5 parts, 8 parts, 10 parts, 12 parts, 15 parts or the range composed of any two of them;

[0038] The dosage of the photoinitiator can be 0.2 parts, 0.5 parts, 0.8 parts, 1 part, 1.5 parts, 2 parts or the range composed of any two of them;

[0039] The dosage of the chain transfer agent can be 0.05 parts, 0.1 parts, 0.5 parts, 1 part, 1.5 parts, 2 parts or the range composed of any two of them;

[0040] The dosage of the tackifying coupling agent can be 0.1 parts, 0.3 parts, 0.5 parts, 0.8 parts, 1 part or the range composed of any two of them;

[0041] The dosage of the antioxidant can be 0.1 parts, 0.5 parts, 1 part, 1.5 parts or the range composed of any two of them;

[0042] The dosage of the leveling agent can be 0.05 parts, 0.1 parts, 0.5 parts, 0.8 parts, 1 part or the range composed of any two of them;

[0043] The dosage of the crosslinking agent can be 0.05 parts, 0.1 parts, 0.5 parts, 1 part, 1.5 parts or the range composed of any two of them.

[0044] In the specific embodiments of the present invention, in the polyol, the molar ratio of polytetrahydrofuran ether diol to polycaprolactone diol is 1:(0.5 - 2), for example, it can be 1:0.5, 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2 or the range composed of any two of them, which is more helpful to balance the improvement of the high temperature and high humidity resistance and adhesion performance of the OCA optical adhesive, etc.

[0045] In a specific embodiment of the present invention, the number-average molecular weight of polytetrahydrofuran ether diol is 1,000 to 3,000; the number-average molecular weight of polycaprolactone diol is 1,000 to 3,000.

[0046] In a specific embodiment of the present invention, in the polyisocyanate, the molar ratio of isophorone diisocyanate to hexamethylene diisocyanate is 1:(0.5 - 2), for example, it can be 1:0.5, 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2 or the range composed of any two of them. Thus, it is more helpful to balance and improve the high-temperature and high-humidity resistance performance and adhesion performance of the OCA optical adhesive, etc.

[0047] In a specific embodiment of the present invention, the molar ratio of polyol to polyisocyanate is 1:(1.2 - 1.5), for example, it can be 1:1.2, 1:1.3, 1:1.4, 1:1.5 or the range composed of any two of them.

[0048] In a specific embodiment of the present invention, the molar ratio of polyol to hydroxy-containing acrylate is 1:(0.8 - 1.2), for example, it can be 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2 or the range composed of any two of them. Further, the hydroxy-containing acrylate includes at least one of 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, and hydroxypropyl acrylate.

[0049] In a specific embodiment of the present invention, the preparation of the polyurethane acrylate prepolymer is carried out under the action of a catalyst. Further, the catalyst includes at least one of dibutyltin dilaurate, triethylenediamine, and stannous octoate. In actual operation, the catalyst is used in a conventional amount. For example, the amount of the catalyst can be 0.02wt% - 1wt% of the total amount of the reactants, etc.

[0050] In a specific embodiment of the present invention, in the preparation of the polyurethane acrylate prepolymer, the raw materials further include a chain extender and / or a filler.

[0051] In a specific embodiment of the present invention, the amount of the chain extender is 0.5wt% - 2wt% of the total amount of the polyol, polyisocyanate, and hydroxy-containing acrylate. For example, it can be 0.5wt%, 0.8wt%, 1wt%, 1.2wt%, 1.5wt%, 1.8wt%, 2wt% or the range composed of any two of them. Thus, the crosslinked network structure in the OCA optical adhesive is further improved, and the high-temperature and high-humidity resistance performance is improved. Further, the chain extender is 1,4-butanediol and / or 1,6-hexanediol.

[0052] In a specific embodiment of the present invention, the dosage of the filler is 8 wt% - 12 wt% of the total amount of the polyol, polyisocyanate, and hydroxyl-containing acrylate. For example, it can be 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, or the range composed of any two of them. Thus, it is more helpful to balance ensuring the high light transmittance and high temperature and high humidity resistance of the OCA optical adhesive. Further, the filler is at least one of nanocellulose, nanoaluminum oxide, and nanosilica, and the particle size of the filler is 1 - 50 nm.

[0053] In a specific embodiment of the present invention, the preparation of the polyurethane acrylate prepolymer includes: reacting the polyol and polyisocyanate at 65 - 75 °C for 2 - 4 h under the action of a catalyst, then adding the hydroxyl-containing acrylate, filler, and chain extender, and continuing to react at 65 - 75 °C for 2 - 3 h to obtain the polyurethane acrylate prepolymer.

[0054] In a specific embodiment of the present invention, the thiourea monomer includes at least one of 1,3 - diallyl 2 - thiourea, allylthiourea, 1 - allyl - 3 - (4 - benzylphenyl)thiourea, 1 - allyl - 3 - (pyridin - 3 - yl)thiourea, 1 - allyl - 3,3 - diethyl - 2 - thiourea, 1 - methallyl - 3 - methyl - 2 - thiourea, and N - allyl N'-2 - hydroxyethylthiourea.

[0055] In a specific embodiment of the present invention, the mass ratio of the thiourea monomer to the polyurethane acrylate prepolymer is (0.5 - 3) : 1. For example, it can be 0.5 : 1, 1 : 1, 1.5 : 1, 2 : 1, 2.5 : 1, 3 : 1, and preferably (1 - 2.5) : 1. Thus, it is more helpful to improve the high temperature and high humidity resistance, etc.

[0056] In a specific embodiment of the present invention, the glass transition temperature of the soft monomer is -60 °C to -10 °C. Further, the soft monomer includes at least one of ethyl acrylate, 2 - ethylhexyl acrylate, lauryl acrylate, butyl acrylate, and isooctyl acrylate.

[0057] In a specific embodiment of the present invention, the hard monomer includes at least one of methyl acrylate, methyl methacrylate, isobornyl acrylate, ethyl methacrylate, styrene, and acrylonitrile.

[0058] In a specific embodiment of the present invention, the functional monomer includes at least one of acrylic acid, acrylamide, N,N - dimethylacrylamide, 2 - hydroxyethyl acrylate, and 2 - hydroxybutyl acrylate.

[0059] In a specific embodiment of the present invention, the photoinitiator includes, but is not limited to, at least one of benzophenone, benzoin dimethyl ether, methyl benzoylformate, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 1-hydroxy-cyclohexyl phenyl ketone, 2,4-diethylthioxanthone, and α-hydroxyisobutyrophenone.

[0060] In a specific embodiment of the present invention, the chain transfer agent includes, but is not limited to, at least one of thioglycolic acid, dodecyl mercaptan, isooctyl thioglycolate, 2-mercaptoethanol, isooctyl 3-mercaptopropionate, and pentaerythritol tetrakis(3-mercaptobutyrate).

[0061] In a specific embodiment of the present invention, the tackifying coupling agent includes, but is not limited to, at least one of vinyltriethoxysilane, dimethyldimethoxysilane, vinyltrimethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, methyldimethoxysilane, and methyltriethoxysilane.

[0062] In a specific embodiment of the present invention, the antioxidant includes, but is not limited to, at least one of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,6-di-tert-butyl-p-cresol, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 4,4'-thiobis(6-tert-butyl-3-methylphenol), and N,N-diphenyl-p-phenylenediamine.

[0063] In a specific embodiment of the present invention, the leveling agent includes, but is not limited to, at least one of Troysol S366, Modaflow2100, TEGO Glide 435, BYK370, BYK333, TEGO Flow ZFS 460, and Perenol S71 UV.

[0064] In a specific embodiment of the present invention, the crosslinking agent includes at least one of diethylene glycol diacrylate, triethylene glycol diacrylate, pentaerythritol triacrylate, and trimethylolpropane triacrylate.

[0065] The second aspect of the present invention provides a preparation method of the high temperature and high humidity resistant OCA optical adhesive provided by the first aspect of the present invention, comprising the following steps: mixing a soft monomer, a hard monomer, a functional monomer, a thiourea monomer, a polyurethane acrylate prepolymer, and a photoinitiator evenly, and then irradiating with ultraviolet light for 3-5 min; then adding a chain transfer agent, a tackifying coupling agent, an antioxidant, a leveling agent, and a crosslinking agent and mixing evenly, and after coating, curing by irradiating with ultraviolet light.

[0066] In a specific embodiment of the present invention, the wavelength of the ultraviolet light irradiation can be 280 - 420 nm.

[0067] In a specific embodiment of the present invention, in the ultraviolet light curing, the energy is 2500 - 3500 mj / cm 2 , for example, it can be 2500 mj / cm 2 , 2800 mj / cm 2 , 3000 mj / cm 2 , 3200 mj / cm 2 , 3500 mj / cm 2 or the range composed of any two of them.

[0068] In a specific embodiment of the present invention, the thickness of the OCA optical adhesive is 50 - 300 μm. For example, it can be 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm or the range composed of any two of them. The specific thickness range can be adjusted according to actual needs. Within this thickness range, both high light transmittance and high temperature and high humidity resistance can be taken into account.

[0069] In a specific embodiment of the present invention, ultraviolet light curing after coating includes: coating the mixture on the release surface of the heavy release film, then laminating the light release film, and then performing ultraviolet light curing.

[0070] In actual operation, the coating can be carried out by conventional coating methods, which can be manual coating or coating by a coater.

[0071] In a specific embodiment of the present invention, the thicknesses of the heavy release film and the light release film are independently selected from 50 - 100 μm. For example, they can be 50 μm, 60 μm, 75 μm, 80 μm, 90 μm, 100 μm or the range composed of any two of them.

[0072] In a specific embodiment of the present invention, the release force of the heavy release film is 20 - 40 gf / in, and the release force of the light release film is 3 - 10 gf / in.

[0073] The third aspect of the present invention provides the application of the high temperature and high humidity resistant OCA optical adhesive provided by the first aspect of the present invention in a display screen.

[0074] Example 1

[0075] This embodiment provides a high-temperature and high-humidity resistant OCA optical adhesive, which comprises the following components in parts by weight: 45 parts of lauryl acrylate, 19 parts of isobornyl acrylate, 15 parts of hydroxybutyl acrylate, 15 parts of allyl thiourea, 5 parts of polyurethane acrylate prepolymer, 0.3 part of photoinitiator methyl benzoylformate, 0.09 part of dodecyl mercaptan, 0.2 part of vinyltriethoxysilane, 0.11 part of antioxidant pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 0.2 part of leveling agent Modaflow 2100, and 0.1 part of triethylene glycol diacrylate.

[0076] Among them, the preparation method of the polyurethane acrylate prepolymer includes: adding 100 g of polycaprolactone diol with a number average molecular weight of 2000 and 100 g of polytetrahydrofuran ether diol with a number average molecular weight of 2000 into an anaerobic reaction kettle, then adding polyisocyanate, and the total molar ratio of polycaprolactone diol to polytetrahydrofuran ether diol is 1:1.3 with the molar ratio of polyisocyanate, heating to 70 °C, then adding 0.2 g of dibutyltin dilaurate, and reacting under stirring for 2.5 h; then adding 11.612 g of 2-hydroxyethyl acrylate, nanocellulose (average particle size is 10 nm), and 1,4-butanediol, and continuing to stir and react at 70 °C for 2 h, cooling to room temperature, and storing in a sealed and light-proof manner. Among them, the polyisocyanate is hexamethylene diisocyanate and isophorone diisocyanate with a molar ratio of 1:1, the addition amount of nanocellulose is 10 wt% of the total amount of polycaprolactone diol, polytetrahydrofuran ether diol, polyisocyanate, and 2-hydroxyethyl acrylate, and the addition amount of 1,4-butanediol is 1 wt% of the total amount of polycaprolactone diol, polytetrahydrofuran ether diol, polyisocyanate, and 2-hydroxyethyl acrylate.

[0077] This embodiment provides a preparation method of the high-temperature and high-humidity resistant OCA optical adhesive, which comprises the following steps:

[0078] After uniformly mixing the soft monomer lauryl acrylate, the hard monomer isobornyl acrylate, the functional monomer hydroxybutyl acrylate, the thiourea monomer allyl thiourea, the polyurethane acrylate prepolymer, and the photoinitiator, irradiate with 365 nm ultraviolet light for 4 min; then add the chain transfer agent dodecyl mercaptan, the tackifying coupling agent vinyltriethoxysilane, the antioxidant pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], the leveling agent Modaflow, and the crosslinking agent triethylene glycol diacrylate and mix uniformly to obtain a mixed solution; then coat the mixed solution on the release surface of a heavy release film with a thickness of 75 μm (release force is 30 gf / in), then laminate a light release film (release force is 5 gf / in), and then cure with ultraviolet light of 365 nm and a total energy of 3000 mj / cm 2 to obtain an OCA optical adhesive with a thickness of 200 μm.

[0079] Example 2

[0080] This embodiment refers to the high temperature and high humidity resistant OCA optical adhesive and preparation method thereof of Embodiment 1, the only difference being that the amounts of the components used are different and the types of thiourea monomers are different.

[0081] The high temperature and high humidity resistant OCA optical adhesive of this embodiment includes the following components in parts by weight: 47 parts of lauryl acrylate, 17 parts of isobornyl acrylate, 15 parts of hydroxybutyl acrylate, 12 parts of 1-allyl-3-(4-benzylphenyl)thiourea, 8 parts of polyurethane acrylate prepolymer, 0.3 parts of photoinitiator methyl benzoylformate, 0.09 parts of dodecyl mercaptan, 0.2 parts of vinyl triethoxysilane, 0.11 parts of antioxidant tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] pentaerythritol ester, 0.2 parts of leveling agent Modaflow 2100 and 0.1 parts of triethylene glycol diacrylate.

[0082] Example 3

[0083] This embodiment refers to the high temperature and high humidity resistant OCA optical adhesive and preparation method thereof of Embodiment 1, the only difference being that the amounts of the components used are different and the types of thiourea monomers are different.

[0084] The high temperature and high humidity resistant OCA optical adhesive of this embodiment includes the following components in parts by weight: 50 parts of lauryl acrylate, 20 parts of isobornyl acrylate, 14 parts of hydroxybutyl acrylate, 10 parts of 1-allyl-3-(4-benzylphenyl)thiourea, 5 parts of polyurethane acrylate prepolymer, 0.3 parts of photoinitiator methyl benzoylformate, 0.09 parts of dodecyl mercaptan, 0.2 parts of vinyl triethoxysilane, 0.11 parts of antioxidant tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] pentaerythritol ester, 0.2 parts of leveling agent Modaflow 2100 and 0.1 parts of triethylene glycol diacrylate.

[0085] Example 4

[0086] This embodiment refers to the high temperature and high humidity resistant OCA optical adhesive and preparation method thereof of Embodiment 1, the only difference being that the amounts of the components used are different and the types of thiourea monomers are different.

[0087] The high-temperature and high-humidity resistant OCA optical adhesive of this embodiment comprises the following components by weight: 45 parts of lauryl acrylate, 20 parts of isobornyl acrylate, 14 parts of hydroxybutyl acrylate, 10 parts of 1-allyl-3-(4-benzylphenyl)thiourea, 10 parts of polyurethane acrylate prepolymer, 0.3 part of photoinitiator methyl benzoylformate, 0.09 part of dodecyl mercaptan, 0.2 part of vinyltriethoxysilane, 0.11 part of antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 0.2 part of leveling agent Modaflow 2100, and 0.1 part of triethylene glycol diacrylate.

[0088] Example 5

[0089] This example refers to the high-temperature and high-humidity resistant OCA optical adhesive and its preparation method in Example 4, with the difference being only the dosages of the thiourea monomer and the polyurethane acrylate prepolymer.

[0090] In this example, the dosage of the thiourea monomer 1-allyl-3-(4-benzylphenyl)thiourea is 5 parts, and the dosage of the polyurethane acrylate prepolymer is 15 parts.

[0091] Example 6

[0092] This example refers to the high-temperature and high-humidity resistant OCA optical adhesive and its preparation method in Example 4, with the difference being only the dosages of the thiourea monomer and the polyurethane acrylate prepolymer.

[0093] In this example, the dosage of the thiourea monomer 1-allyl-3-(4-benzylphenyl)thiourea is 15 parts, and the dosage of the polyurethane acrylate prepolymer is 5 parts.

[0094] Comparative Example 1

[0095] Comparative Example 1 refers to the high-temperature and high-humidity resistant OCA optical adhesive and its preparation method in Example 1, with the differences being different dosages of each component and the absence of the thiourea monomer and the polyurethane acrylate prepolymer.

[0096] The OCA optical adhesive of Comparative Example 1 comprises the following components by weight: 55 parts of lauryl acrylate, 25 parts of isobornyl acrylate, 19 parts of hydroxybutyl acrylate, 0.3 part of photoinitiator methyl benzoylformate, 0.09 part of dodecyl mercaptan, 0.2 part of vinyltriethoxysilane, 0.11 part of antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 0.2 part of leveling agent Modaflow 2100, and 0.1 part of triethylene glycol diacrylate.

[0097] Comparative Example 2

[0098] Comparative Example 2 refers to the high-temperature and high-humidity resistant OCA optical adhesive and its preparation method in Example 1, with the difference that the dosages of each component are different and the polyurethane acrylate prepolymer is different.

[0099] The OCA optical adhesive of Comparative Example 2 includes the following components by weight: 50 parts of lauryl acrylate, 20 parts of isobornyl acrylate, 14 parts of hydroxybutyl acrylate, 10 parts of 1-allyl-3-(4-benzylphenyl)thiourea, 5 parts of polyurethane acrylate prepolymer, 0.3 part of photoinitiator methyl benzoylformate, 0.09 part of dodecyl mercaptan, 0.2 part of vinyltriethoxysilane, 0.11 part of antioxidant pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 0.2 part of leveling agent Modaflow 2100, and 0.1 part of triethylene glycol diacrylate.

[0100] The preparation method of the polyurethane acrylate prepolymer refers to the polyurethane acrylate prepolymer in Example 1, with the difference that: 200 g of polycaprolactone diol with a number average molecular weight of 2000 is used to replace 100 g of polycaprolactone diol with a number average molecular weight of 2000 and 100 g of polytetrahydrofuran ether diol with a number average molecular weight of 2000 in Example 1; hexamethylene diisocyanate is used to replace hexamethylene diisocyanate and isophorone diisocyanate in Example 1 in an equimolar amount.

[0101] Comparative Example 3

[0102] Comparative Example 3 refers to the high-temperature and high-humidity resistant OCA optical adhesive and its preparation method in Example 1, with the difference that the dosages of each component are different and the polyurethane acrylate prepolymer is different.

[0103] The OCA optical adhesive of Comparative Example 3 includes the following components by weight: 50 parts of lauryl acrylate, 20 parts of isobornyl acrylate, 14 parts of hydroxybutyl acrylate, 10 parts of 1-allyl-3-(4-benzylphenyl)thiourea, 5 parts of polyurethane acrylate prepolymer, 0.3 part of photoinitiator methyl benzoylformate, 0.09 part of dodecyl mercaptan, 0.2 part of vinyltriethoxysilane, 0.11 part of antioxidant pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 0.2 part of leveling agent Modaflow 2100, and 0.1 part of triethylene glycol diacrylate.

[0104] The preparation method of the polyurethane acrylate prepolymer refers to the polyurethane acrylate prepolymer in Example 1, with the differences being that 200 g of polytetrahydrofuran glycol with a number average molecular weight of 2000 is used to replace 100 g of polycaprolactone glycol with a number average molecular weight of 2000 and 100 g of polytetrahydrofuran glycol with a number average molecular weight of 2000 in Example 1; and hexamethylene diisocyanate is used in an equimolar amount to replace hexamethylene diisocyanate and isophorone diisocyanate in Example 1.

[0105] Comparative Example 4

[0106] Comparative Example 4 refers to the high temperature and high humidity resistant OCA optical adhesive and its preparation method in Example 1, with the differences being that the amounts of each component are different and the polyurethane acrylate prepolymer is different.

[0107] The OCA optical adhesive of Comparative Example 4 includes the following components by weight: 50 parts of lauryl acrylate, 20 parts of isobornyl acrylate, 14 parts of hydroxybutyl acrylate, 10 parts of 1 - allyl - 3 - (4 - benzylphenyl) thiourea, 5 parts of polyurethane acrylate prepolymer, 0.3 part of photoinitiator methyl benzoylformate, 0.09 part of dodecyl mercaptan, 0.2 part of vinyltriethoxysilane, 0.11 part of antioxidant pentaerythritol tetrakis[β - (3,5 - di - tert - butyl - 4 - hydroxyphenyl) propionate], 0.2 part of leveling agent Modaflow 2100, and 0.1 part of triethylene glycol diacrylate.

[0108] The preparation method of the polyurethane acrylate prepolymer refers to the polyurethane acrylate prepolymer in Example 1, with the difference being that hexamethylene diisocyanate is used in an equimolar amount to replace hexamethylene diisocyanate and isophorone diisocyanate in Example 1.

[0109] Comparative Example 5

[0110] Comparative Example 5 refers to the high temperature and high humidity resistant OCA optical adhesive and its preparation method in Example 1, with the differences being that the amounts of each component are different and it does not include a polyurethane acrylate prepolymer.

[0111] The OCA optical adhesive of Comparative Example 5 includes the following components by weight: 53 parts of lauryl acrylate, 21 parts of isobornyl acrylate, 15 parts of hydroxybutyl acrylate, 10 parts of 1 - allyl - 3 - (4 - benzylphenyl) thiourea, 0.3 part of photoinitiator methyl benzoylformate, 0.09 part of dodecyl mercaptan, 0.2 part of vinyltriethoxysilane, 0.11 part of antioxidant pentaerythritol tetrakis[β - (3,5 - di - tert - butyl - 4 - hydroxyphenyl) propionate], 0.2 part of leveling agent Modaflow 2100, and 0.1 part of triethylene glycol diacrylate.

[0112] Comparative Example 6

[0113] Comparative Example 6 refers to the high-temperature and high-humidity resistant OCA optical adhesive and its preparation method in Example 1, with the difference being that the dosages of each component are different and it does not include polyurethane acrylate prepolymer.

[0114] The OCA optical adhesive of Comparative Example 6 includes the following components by weight: 55 parts of lauryl acrylate, 23 parts of isobornyl acrylate, 16 parts of hydroxybutyl acrylate, 5 parts of polyurethane acrylate prepolymer, 0.3 part of photoinitiator methyl benzoylformate, 0.09 part of dodecyl mercaptan, 0.2 part of vinyltriethoxysilane, 0.11 part of antioxidant pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 0.2 part of leveling agent Modaflow 2100, and 0.1 part of triethylene glycol diacrylate.

[0115] Experimental Example

[0116] The following performance tests were conducted on the OCA optical adhesives of different examples and comparative examples, and the test results are shown in Table 1.

[0117] Optical performance test: It was adhered according to the structure of a 7-inch glass cover plate / OCA optical adhesive / supporting ITO sheet, and then detected in accordance with GB / T 2410-2008 "Determination of Transmittance and Haze of Transparent Plastics".

[0118] Gel content test: The OCA optical adhesive was cut into small pieces of similar size. Half of them were post-cured at 5000 mj / cm 2 and then wound around a glass rod. The initial mass of the OCA optical adhesive was recorded as Ms. It was placed in a beaker containing 250 mL of ethyl acetate. After 24 h, the solvent was filtered out with a 300-mesh filter screen. The remaining OCA optical adhesive was dried in an oven at 120 °C for 30 min, and its remaining weight was recorded as Me. The gel content (G) was calculated through the following formula: G = Me / Ms.

[0119] Table 1 Performance test results of each OCA optical adhesive

[0120]

[0121] From the test results in Table 1, it can be seen that the OCA optical adhesive of the present invention has good optical performance and crosslinking effect.

[0122] The following further performance tests were conducted on the OCA optical adhesives of different examples and comparative examples, and the test results are shown in Table 2.

[0123] Adhesion test: Tear off the light release film of each OCA optical adhesive, stick it on a 50μm transparent PET film respectively, cut it into samples with a width of 25.4mm and a length of 200mm using a manual sampler. After tearing off the heavy release film, stick it on a SUS 304 steel plate, roll it back and forth 3 times with a 2kg roller at a speed of 600mm / min, place it in an environment of 25℃, 60℃, 90℃, 60℃ / 90%RH and 85℃ / 85%RH respectively for 20min, and use a tensile testing machine to test its 180° peel adhesion force.

[0124] Table 2 Test results of peel force of each OCA optical adhesive under different conditions

[0125]

[0126] From the test results in Table 2, it can be seen that the OCA optical adhesive of the present invention has excellent high temperature and high humidity resistance, can maintain good cohesion under high temperature and high humidity conditions, and has higher adhesion force.

[0127] Further test the aging resistance performance of the OCA optical adhesives of different examples and comparative examples, and the test results are shown in Table 3.

[0128] Aging resistance performance test: Stick each OCA optical adhesive on a glass cover plate, after degassing, treat it with an LED lamp with a total energy of 3000mj / cm 2 , and then put it into an environment of 25℃, 90℃, 110℃, 85℃ / 85%RH and 110℃ / 90%RH respectively for 1000h. During this period, observe whether there are bubbles or other phenomena in the samples. If there are, it is marked as ×, if not, it is marked as √.

[0129] Table 3 Test results of aging resistance performance of each OCA optical adhesive

[0130]

[0131] From the test results in Table 3, it can be seen that the OCA optical adhesive of the present invention has excellent aging resistance performance, and no bubble rebound or degumming occurs in a high temperature and high humidity environment.

[0132] In summary, the light transmittance of the OCA optical adhesive of the present invention is above 90%, the haze is <1, and no bubble rebound or degumming occurs after being kept in a high temperature and high humidity environment (temperature 100 - 150℃, humidity 60% - 90%) for 1000h, showing excellent high temperature and high humidity resistance performance.

[0133] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of the present invention.

Claims

1. High temperature and high humidity resistant OCA optical adhesive, characterized in that: The invention comprises the following components in parts by weight: 40-55 parts of soft monomer, 10-25 parts of hard monomer, 5-20 parts of functional monomer, 5-15 parts of thiourea monomer, 3-15 parts of polyurethane acrylate prepolymer, 0.2-2 parts of photoinitiator, 0.05-2 parts of chain transfer agent, 0.1-1 parts of tackifying coupling agent, 0.1-1.5 parts of antioxidant, 0.05-1 parts of leveling agent and 0.05-1.5 parts of crosslinking agent; The polyurethane acrylate prepolymer is mainly prepared by reacting a polyol, a polyisocyanate and a hydroxyl-containing acrylate; the polyol includes polytetramethylene ether diol and polycaprolactone diol, and the molar ratio of the polytetramethylene ether diol to the polycaprolactone diol is 1: (0.5-2); the polyisocyanate includes isophorone diisocyanate and hexamethylene diisocyanate, and the molar ratio of the isophorone diisocyanate to the hexamethylene diisocyanate is 1: (0.5-2); The thiourea monomer includes at least one of 1,3-diallyl 2-thiourea, allyl thiourea, 1-allyl-3-(4-benzylphenyl)thiourea, 1-allyl-3-(pyridin-3-yl)thiourea, 1-allyl-3,3-diethyl-2-thiourea, 1-methallyl-3-methyl-2-thiourea and N-propylene N'-2-hydroxyethylthiourea; The functional monomer includes at least one of acrylic acid, acrylamide, N,N-dimethylacrylamide, hydroxyethyl acrylate and hydroxybutyl acrylate.

2. The high temperature and high humidity resistant OCA optical adhesive according to claim 1, characterized in that: Having at least one of the following characteristics: (1) The molar ratio of the polyol to the polyisocyanate is 1:(1.2-1.5); (2) The molar ratio of the polyol to the hydroxyl-containing acrylate is 1: (0.8-1.2); (3) The hydroxyl-containing acrylate includes at least one of 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate and hydroxypropyl acrylate; (4) The preparation of the polyurethane acrylate prepolymer is carried out under the action of a catalyst; the catalyst comprises at least one of dibutyltin dilaurate, triethylenediamine and stannous octoate; (5) In the preparation of the polyurethane acrylate prepolymer, the raw materials also include a chain extender and / or a filler.

3. The high temperature and high humidity resistant OCA optical adhesive according to claim 1, characterized in that: The mass ratio of the thiourea monomer to the polyurethane acrylate prepolymer is (0.5-3):

1.

4. The high temperature and high humidity resistant OCA optical adhesive according to claim 1, characterized in that: Having at least one of the following characteristics: (1) The soft monomer includes at least one of ethyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate and butyl acrylate; (2) the hard monomer comprises at least one of methyl acrylate, methyl methacrylate, isobornyl acrylate, ethyl methacrylate, styrene and acrylonitrile; (3) The crosslinking agent includes at least one of diethylene glycol diacrylate, triethylene glycol diacrylate, pentaerythritol triacrylate and trimethylolpropane triacrylate.

5. The method for preparing the high temperature and high humidity resistant OCA optical adhesive according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: uniformly mixing soft monomers, hard monomers, functional monomers, thiourea monomers, polyurethane acrylate prepolymers and photoinitiators, irradiating with ultraviolet light for 3 to 5 minutes, then adding chain transfer agents, viscosity enhancing coupling agents, antioxidants, leveling agents and crosslinking agents, mixing them uniformly, and curing with ultraviolet light after coating.

6. The preparation method according to claim 5, characterized in that: The thickness of the OCA optical adhesive is 50-300 μm.

7. Use of the high temperature and high humidity resistant OCA optical adhesive described in any one of claims 1 to 4 or the high temperature and high humidity resistant OCA optical adhesive prepared by the preparation method described in any one of claims 5 to 6 in display screens.

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