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

Abstract

The invention relates to the technical field of optical cement, in particular to high-temperature-resistant and high-humidity-resistant OCA (Optical Clear Adhesive) as well as a preparation method and application thereof. The high-temperature-resistant and high-humidity-resistant OCA optical adhesive is prepared from 40 to 55 parts of a soft monomer, 10 to 25 parts of a hard monomer, 5 to 20 parts of a functional monomer, 5 to 15 parts of a thiourea monomer, 3 to 15 parts of a polyurethane acrylate prepolymer, 0.2 to 2 parts of a photoinitiator, 0.05 to 2 parts of a chain transfer agent, 0.1 to 1 part of a tackifying coupling agent, 0.1 to 1.5 parts of an antioxidant, 0.05 to 1 part of a flatting agent and 0.05 to 1.5 parts of a cross-linking agent, the polyurethane acrylate prepolymer is mainly prepared from polyol, polyisocyanate and hydroxyl-containing acrylate through a reaction. The OCA optical cement disclosed by the invention not only has the characteristic of high light transmittance, but also can keep good adhesion, stability and durability in a high-temperature and high-humidity extreme environment.

Description

Technical Field

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

[0002] With the continuous development of science and technology, the popularity and diversified applications of electronic products have put forward higher requirements for material performance. As a key material, OCA optical adhesive is widely used in display screens of various products such as smartphones, tablets, electronic watches, and automobiles. As the importance of various devices in daily life continues to increase and the use environment becomes increasingly complex, many devices need to operate under high temperature and high humidity conditions. Therefore, the market demand for the optical performance, adhesion and durability of OCA optical adhesives in extreme environments such as high temperature and high humidity continues to increase. Traditional optical adhesives are prone to yellowing, blistering or delamination in such extreme environments, affecting the display effect and service life of the equipment. 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, it has become an urgent need for the industry to develop environmentally friendly OCA optical adhesives that can maintain excellent performance under high temperature and high humidity conditions.

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

[0004] The purpose of the present invention is to provide a high temperature and high humidity resistant OCA optical adhesive and a preparation method and 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] In order to achieve the above-mentioned object of the present invention, the first aspect of the present invention provides a high temperature and high humidity resistant OCA optical adhesive, comprising the following components in parts by weight: 40 to 55 parts of soft monomers, 10 to 25 parts of hard monomers, 5 to 20 parts of functional monomers, 5 to 15 parts of thiourea monomers, 3 to 15 parts of polyurethane acrylate prepolymers, 0.2 to 2 parts of photoinitiators, 0.05 to 2 parts of chain transfer agents, 0.1 to 1 parts of tackifying coupling agents, 0.1 to 1.5 parts of antioxidants, 0.05 to 1 parts of leveling agents, and 0.05 to 1.5 parts of cross-linking agents; The polyurethane acrylate prepolymer is mainly prepared by reacting polyol, polyisocyanate and hydroxyl-containing acrylate; the polyol includes polytetramethylene ether diol and polycaprolactone diol, and the polyisocyanate includes isophorone diisocyanate and hexamethylene diisocyanate.

[0006] In a specific embodiment of the present invention, in the polyol, the molar ratio of the polytetramethylene ether diol to the polycaprolactone diol is 1:(0.5-2).

[0007] In a specific embodiment of the present invention, in the polyisocyanate, the molar ratio of the isophorone diisocyanate to the hexamethylene diisocyanate is 1:(0.5-2).

[0008] In a specific embodiment of the present invention, the molar ratio of the polyol to the polyisocyanate is 1:(1.2-1.5).

[0009] 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.

[0010] 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.

[0011] 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.

[0012] In a specific embodiment of the present invention, the amount of the chain extender is 0.5 wt% to 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.

[0013] In a specific embodiment of the present invention, the amount of the filler is 8wt% to 12wt% of the total amount of the polyol, the polyisocyanate and the hydroxyl-containing acrylate. Further, the filler is at least one of nanocellulose, nanoalumina and nanosilicon dioxide; and the particle size of the filler is 1 to 50nm.

[0014] 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-propylene N'-2-hydroxyethylthiourea.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] In a specific embodiment of the present invention, the functional monomer includes at least one of acrylic acid, acrylamide, N,N-dimethylacrylamide, hydroxyethyl acrylate and hydroxybutyl acrylate.

[0019] 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.

[0020] The second aspect of the present invention provides a method for preparing the high temperature and high humidity resistant OCA optical adhesive provided by the first aspect of the present invention, comprising the following steps: after the soft monomer, hard monomer, functional monomer, thiourea monomer, polyurethane acrylate prepolymer and photoinitiator are mixed evenly, ultraviolet light is used for 3 to 5 minutes, and then a chain transfer agent, a tackifying coupling agent, an antioxidant, a leveling agent and a cross-linking agent are added and mixed evenly, and after coating, ultraviolet light is used for curing.

[0021] In a specific embodiment of the present invention, the thickness of the OCA optical adhesive is 50-300 μm.

[0022] The third aspect of the present invention provides 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.

[0023] Compared with the prior art, the present invention has the following beneficial effects: (1) The OCA optical adhesive of the present invention not only has the characteristics of high light transmittance, but also can maintain good adhesion, stability and durability under extreme conditions of high temperature and high humidity, can prevent blistering or delamination caused by water vapor penetration, and is not prone to deformation or failure; (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. DETAILED DESCRIPTION

[0024] The technical scheme of the present invention will be clearly and completely described below in conjunction with specific embodiments, but it will be appreciated by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work, all belong to the scope of protection of the present invention. If specific conditions are not indicated in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0025] The first aspect of the present invention provides a high temperature and high humidity resistant OCA optical adhesive, comprising the following components by weight: 40 to 55 parts of soft monomers, 10 to 25 parts of hard monomers, 5 to 20 parts of functional monomers, 5 to 15 parts of thiourea monomers, 3 to 15 parts of polyurethane acrylate prepolymers, 0.2 to 2 parts of photoinitiators, 0.05 to 2 parts of chain transfer agents, 0.1 to 1 parts of tackifying coupling agents, 0.1 to 1.5 parts of antioxidants, 0.05 to 1 parts of leveling agents, and 0.05 to 1.5 parts of crosslinking agents; The polyurethane acrylate prepolymer is mainly prepared by the reaction of polyols, polyisocyanates and hydroxyl-containing acrylates; the polyols include polytetramethylene ether diol and polycaprolactone diol, and the polyisocyanates include isophorone diisocyanate and hexamethylene diisocyanate.

[0026] 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 under extreme conditions of high temperature and high humidity, can prevent blistering or delamination caused by water vapor penetration, and is not prone to deformation or failure.

[0027] 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 a polyurethane segment with excellent thermal stability and hydrolysis resistance into the OCA optical adhesive system, and the acrylate segment is polymerized with various monomers to form a cross-linked network structure, which is combined with more hydrophobic groups and intermolecular hydrogen bonds 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.

[0028] The present invention uses the above components and adjusts the ratio to ensure both high light transmittance and high temperature and humidity resistance of the OCA optical adhesive. For example, in different embodiments, the amount of each component in the high temperature and humidity resistant OCA optical adhesive can be as follows by weight: The amount of the soft monomer can be 40 parts, 42 parts, 45 parts, 48 ​​parts, 50 parts, 52 parts, 55 parts or a range consisting of any two of them; The amount of the hard monomer can be 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts or a range consisting of any two of them; The amount of the functional monomer can be 5 parts, 8 parts, 10 parts, 12 parts, 15 parts, 18 parts, 20 parts or a range consisting of any two of them; The amount of thiourea monomer can be 5 parts, 8 parts, 10 parts, 12 parts, 15 parts or a range consisting of any two of them; The amount of the polyurethane acrylate prepolymer can be 3 parts, 5 parts, 8 parts, 10 parts, 12 parts, 15 parts or a range consisting of any two of them; The amount of the photoinitiator can be 0.2 parts, 0.5 parts, 0.8 parts, 1 part, 1.5 parts, 2 parts or any two thereof; The amount of the chain transfer agent can be 0.05 parts, 0.1 parts, 0.5 parts, 1 parts, 1.5 parts, 2 parts or any two thereof; The amount of the tackifying coupling agent can be 0.1 part, 0.3 part, 0.5 part, 0.8 part, 1 part or a range consisting of any two thereof; The amount of the antioxidant can be 0.1 part, 0.5 part, 1 part, 1.5 parts or a range consisting of any two of them; The amount of the leveling agent can be 0.05 part, 0.1 part, 0.5 part, 0.8 part, 1 part or a range consisting of any two of them; The amount of the cross-linking agent can be 0.05 parts, 0.1 parts, 0.5 parts, 1 part, 1.5 parts or a range consisting of any two of them.

[0029] In a specific embodiment of the present invention, in the polyol, the molar ratio of polytetramethylene glycol to polycaprolactone glycol 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 a range consisting of any two of them, which is more helpful to improve the high temperature and high humidity resistance and bonding performance of the OCA optical adhesive.

[0030] In a specific embodiment of the present invention, the number average molecular weight of polytetramethylene ether diol is 1000-3000; the number average molecular weight of polycaprolactone diol is 1000-3000.

[0031] 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 a range consisting of any two of them, which is more helpful to improve the high temperature and high humidity resistance and bonding performance of the OCA optical adhesive.

[0032] 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 a range consisting of any two of them.

[0033] 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), for example, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2 or a range consisting of any two thereof. Furthermore, the hydroxyl-containing acrylate includes at least one of 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate and hydroxypropyl acrylate.

[0034] 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% to 1wt% of the total amount of the reactants.

[0035] 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.

[0036] In a specific embodiment of the present invention, the amount of the chain extender is 0.5wt% to 2wt% of the total amount of the polyol, polyisocyanate and hydroxyl-containing acrylate, for example, it can be 0.5wt%, 0.8wt%, 1wt%, 1.2wt%, 1.5wt%, 1.8wt%, 2wt% or any two thereof, thereby further improving the cross-linked network structure in the OCA optical adhesive and improving the high temperature and high humidity resistance. Further, the chain extender is 1,4-butanediol and / or 1,6-hexanediol.

[0037] In a specific embodiment of the present invention, the amount of filler is 8wt% to 12wt% of the total amount of polyol, polyisocyanate and hydroxyl-containing acrylate, for example, it can be 8wt%, 9wt%, 10wt%, 11wt%, 12wt% or a range composed of any two of them, which is more helpful to ensure the high light transmittance and high temperature and humidity resistance of OCA optical glue. Further, the filler is at least one of nanocellulose, nanoalumina and nanosilicon dioxide, and the particle size of the filler is 1 to 50nm.

[0038] In a specific embodiment of the present invention, the preparation of the polyurethane acrylate prepolymer includes: reacting polyol and polyisocyanate at 65-75°C for 2-4 hours under the action of a catalyst, then adding hydroxyl-containing acrylate, filler and chain extender, and continuing to react at 65-75°C for 2-3 hours to obtain the polyurethane acrylate prepolymer.

[0039] 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-propylene N'-2-hydroxyethylthiourea.

[0040] In a specific embodiment of the present invention, the mass ratio of thiourea monomer to 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, preferably (1-2.5) : 1, which is more helpful to improve high temperature and high humidity resistance and the like.

[0041] 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.

[0042] 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.

[0043] In a specific embodiment of the present invention, the functional monomer includes at least one of acrylic acid, acrylamide, N,N-dimethylacrylamide, hydroxyethyl acrylate and hydroxybutyl acrylate.

[0044] In a specific embodiment of the present invention, the photoinitiator includes but is not limited to at least one of benzophenone, benzil dimethyl ether, methyl benzoylformate, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 1-hydroxy-cyclohexyl benzophenone, 2,4-diethylthioxanthone and α-hydroxyisobutyrophenone.

[0045] 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).

[0046] In a specific embodiment of the present invention, the adhesion-enhancing coupling agent includes but is not limited to at least one of vinyltriethoxysilane, dimethyldimethoxysilane, vinyltrimethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, methyldimethoxysilane and methyltriethoxysilane.

[0047] In a specific embodiment of the present invention, the antioxidant includes but is not limited to at least one of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol ester, 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.

[0048] In a specific embodiment of the present invention, the leveling agent includes but is not limited to at least one of Troysol S366, Modaflow 2100, TEGO Glide 435, BYK 370, BYK 333, TEGO Flow ZFS 460 and Perenol S71 UV.

[0049] 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.

[0050] The second aspect of the present invention provides a method for preparing the high temperature and high humidity resistant OCA optical adhesive provided by the first aspect of the present invention, comprising the following steps: after 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 a chain transfer agent, a tackifying coupling agent, an antioxidant, a leveling agent and a cross-linking agent, mixing evenly, and curing with ultraviolet light after coating.

[0051] In a specific embodiment of the present invention, the wavelength of the ultraviolet light can be 280 to 420 nm.

[0052] In a specific embodiment of the present invention, the energy during UV curing is 2500-3500 mj / cm 2 , for example, 2500 mj / cm 2 、2800mj / cm 2 、3000mj / cm 2 、3200mj / cm 2 、3500mj / cm 2 Or a range consisting of any two of them.

[0053] In a specific embodiment of the present invention, the thickness of the OCA optical adhesive is 50 to 300 μm, for example, it can be 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm or a 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.

[0054] In a specific embodiment of the present invention, curing by ultraviolet light after coating includes: coating the mixture on the release surface of the heavy release film, laminating the light release film, and then curing by ultraviolet light.

[0055] In actual operation, coating can be carried out by conventional coating methods, either manually or by using a coating machine.

[0056] In a specific embodiment of the present invention, the thickness of the heavy release film and the light release film are independently selected from 50 to 100 μm, for example, 50 μm, 60 μm, 75 μm, 80 μm, 90 μm, 100 μm or any two thereof.

[0057] In a specific embodiment of the present invention, the release force of the heavy release film is 20 to 40 gf / in, and the release force of the light release film is 3 to 10 gf / in.

[0058] The third aspect of the present invention provides 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.

[0059] Example 1 The present embodiment provides a high temperature and high humidity resistant OCA optical adhesive, including 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 parts of photoinitiator methyl benzoylformate, 0.09 parts of dodecyl mercaptan, 0.2 parts of vinyl triethoxy silane, 0.11 parts of antioxidant tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] pentaerythritol ester, 0.2 parts of leveling agent Modaflow2100 and 0.1 parts of triethylene glycol diacrylate.

[0060] Among them, the preparation method of the polyurethane acrylate prepolymer includes: in an anaerobic reactor, adding 100g of polycaprolactone diol with a number average molecular weight of 2000, 100g of polytetramethylene glycol with a number average molecular weight of 2000, and then adding polyisocyanate, and the total molar ratio of polycaprolactone diol to polytetramethylene glycol to the molar ratio of polyisocyanate is 1:1.3, heating to 70°C, and then adding 0.2g of dibutyltin dilaurate, and reacting under stirring for 2.5h; then adding 11.612g of 2-hydroxyethyl acrylate, nanocellulose (average particle size of 10nm), and 1,4-butanediol, continuing to stir and react at 70°C for 2h, cooling to room temperature, and sealing and storing away from light. Among them, the polyisocyanate is hexamethylene diisocyanate and isophorone diisocyanate with a molar ratio of 1:1, the added amount of nanocellulose is 10wt% of the total amount of polycaprolactone diol, polytetramethylene ether diol, polyisocyanate and 2-hydroxyethyl acrylate, and the added amount of 1,4-butanediol is 1wt% of the total amount of polycaprolactone diol, polytetramethylene ether diol, polyisocyanate and 2-hydroxyethyl acrylate.

[0061] This embodiment provides a method for preparing high temperature and high humidity resistant OCA optical adhesive, comprising the following steps: After 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 are mixed evenly, irradiated with 365nm ultraviolet light for 4min; then the chain transfer agent dodecyl mercaptan, the viscosity increasing coupling agent vinyl triethoxysilane, the antioxidant tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester, the leveling agent Modaflow and the cross-linking agent triethylene glycol diacrylate are added and mixed evenly to obtain a mixed solution; then the mixture is coated on the release surface of a heavy release film with a thickness of 75μm (release force of 30gf / in), and then a light release film (release force of 5gf / in) is attached, and then the mixture is irradiated with 365nm and a total energy of 3000mj / cm 2 The OCA optical adhesive with a thickness of 200 μm was obtained by ultraviolet light curing.

[0062] Example 2 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.

[0063] 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.

[0064] Example 3 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.

[0065] 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.

[0066] Example 4 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.

[0067] The high temperature and high humidity resistant OCA optical adhesive of this embodiment includes the following components in parts 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 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.

[0068] Example 5 This embodiment refers to the high temperature and high humidity resistant OCA optical adhesive and preparation method thereof of embodiment 4, the only difference being that the amounts of thiourea monomer and polyurethane acrylate prepolymer used are different.

[0069] In this embodiment, the amount of thiourea monomer 1-allyl-3-(4-benzylphenyl)thiourea used is 5 parts, and the amount of polyurethane acrylate prepolymer used is 15 parts.

[0070] Example 6 This embodiment refers to the high temperature and high humidity resistant OCA optical adhesive and preparation method thereof of embodiment 4, the only difference being that the amounts of thiourea monomer and polyurethane acrylate prepolymer used are different.

[0071] In this embodiment, the amount of thiourea monomer 1-allyl-3-(4-benzylphenyl)thiourea used is 15 parts, and the amount of polyurethane acrylate prepolymer used is 5 parts.

[0072] Comparative Example 1 Comparative Example 1 refers to the high temperature and high humidity resistant OCA optical adhesive and its preparation method of Example 1, except that the amounts of the components are different, and thiourea monomer and polyurethane acrylate prepolymer are not included.

[0073] The OCA optical adhesive of Comparative Example 1 includes the following components in parts by weight: 55 parts of lauryl acrylate, 25 parts of isobornyl acrylate, 19 parts of hydroxybutyl acrylate, 0.3 parts of photoinitiator methyl benzoylformate, 0.09 parts of dodecyl mercaptan, 0.2 parts of vinyl triethoxy silane, 0.11 parts of antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 0.2 parts of leveling agent Modaflow 2100 and 0.1 parts of triethylene glycol diacrylate.

[0074] Comparative Example 2 Comparative Example 2 refers to the high temperature and high humidity resistant OCA optical adhesive and its preparation method of Example 1, the difference being that the amounts of the components used are different and the polyurethane acrylate prepolymers are different.

[0075] The OCA optical adhesive of Comparative Example 2 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.

[0076] The preparation method of the polyurethane acrylate prepolymer refers to the polyurethane acrylate prepolymer of Example 1, except that: 200g of polycaprolactone diol with a number average molecular weight of 2000 is used to replace 100g of polycaprolactone diol with a number average molecular weight of 2000 and 100g of polytetramethylene furan ether diol with a number average molecular weight of 2000 in Example 1; hexamethylene diisocyanate is used in equal molar amounts to replace hexamethylene diisocyanate and isophorone diisocyanate in Example 1.

[0077] Comparative Example 3 Comparative Example 3 refers to the high temperature and high humidity resistant OCA optical adhesive and its preparation method of Example 1, the difference being that the amounts of the components used are different and the polyurethane acrylate prepolymers are different.

[0078] The OCA optical adhesive of Comparative Example 3 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.

[0079] The preparation method of the polyurethane acrylate prepolymer refers to the polyurethane acrylate prepolymer of Example 1, except that: 200g of polytetramethylene ether diol with a number average molecular weight of 2000 is used to replace 100g of polycaprolactone diol with a number average molecular weight of 2000 and 100g of polytetramethylene ether diol with a number average molecular weight of 2000 in Example 1; hexamethylene diisocyanate is used in an equal molar amount to replace hexamethylene diisocyanate and isophorone diisocyanate in Example 1.

[0080] Comparative Example 4 Comparative Example 4 refers to the high temperature and high humidity resistant OCA optical adhesive and its preparation method of Example 1, the difference being that the amounts of the components used are different and the polyurethane acrylate prepolymers are different.

[0081] The OCA optical adhesive of Comparative Example 4 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.

[0082] The preparation method of the polyurethane acrylate prepolymer refers to the polyurethane acrylate prepolymer of Example 1, except that hexamethylene diisocyanate is used in an equal molar amount to replace the hexamethylene diisocyanate and isophorone diisocyanate in Example 1.

[0083] Comparative Example 5 Comparative Example 5 refers to the high temperature and high humidity resistant OCA optical adhesive and its preparation method of Example 1, except that the amounts of each component are different and the polyurethane acrylate prepolymer is not included.

[0084] The OCA optical adhesive of Comparative Example 5 includes the following components in parts 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 parts of photoinitiator methyl benzoylformate, 0.09 parts of dodecyl mercaptan, 0.2 parts of vinyl triethoxysilane, 0.11 parts of antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 0.2 parts of leveling agent Modaflow 2100 and 0.1 parts of triethylene glycol diacrylate.

[0085] Comparative Example 6 Comparative Example 6 refers to the high temperature and high humidity resistant OCA optical adhesive and its preparation method of Example 1, the difference being that the amounts of the components are different and the polyurethane acrylate prepolymer is not included.

[0086] The OCA optical adhesive of Comparative Example 6 includes the following components in parts 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 parts of photoinitiator methyl benzoylformate, 0.09 parts of dodecyl mercaptan, 0.2 parts of vinyl triethoxy silane, 0.11 parts of antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 0.2 parts of leveling agent Modaflow 2100 and 0.1 parts of triethylene glycol diacrylate.

[0087] Experimental example The following performance tests were conducted on the OCA optical adhesives of different embodiments and comparative examples, and the test results are shown in Table 1.

[0088] Optical performance test: According to the structure of 7-inch glass cover / OCA optical glue / matching ITO sheet, the test is carried out according to GB / T 2410-2008 "Determination of light transmittance and haze of transparent plastics".

[0089] Gel content test: Cut the OCA optical glue into small pieces of similar size, and test half of them at 5000mj / cm 2 After post-curing treatment, wrap it around a glass rod, record the initial mass of the OCA optical glue as Ms, put it into a beaker filled with 250mL of ethyl acetate, filter out the solvent with a 300-mesh filter after 24 hours, bake the remaining OCA optical glue in an oven at 120°C for 30 minutes, record its remaining weight as Me, and calculate the gel content (G) by the following formula: G=Me / Ms.

[0090] Table 1 Test results of various OCA optical adhesive properties

[0091] From the test results in Table 1, it can be seen that the OCA optical adhesive of the present invention has good optical properties and cross-linking effect.

[0092] The following performance tests were further conducted on the OCA optical adhesives of different embodiments and comparative examples. The test results are shown in Table 2.

[0093] Adhesion test: tear off the light release films of each OCA optical adhesive, stick them on a 50μm transparent PET film respectively, use a manual sampler to cut into samples with a width of 25.4mm and a length of 200mm, tear off the heavy release film and stick it on a SUS 304 steel plate, use a 2kg roller to roll back and forth 3 times at a speed of 600mm / min, place them in 25℃, 60℃, 90℃, 60℃ / 90%RH and 85℃ / 85%RH environments for 20min, and use a tensile testing machine to test its 180° peeling adhesion.

[0094] Table 2 Peel force test results of various OCA optical adhesives under different conditions

[0095] From the test results in Table 2, it can be seen that the OCA optical adhesive of the present invention has excellent resistance to high temperature and high humidity, can maintain good cohesion under high temperature and high humidity conditions, and has higher adhesion.

[0096] The aging resistance of the OCA optical adhesives of different embodiments and comparative examples was further tested, and the test results are shown in Table 3.

[0097] Aging resistance test: Each OCA optical adhesive is bonded to the glass cover plate, and after degassing, it is subjected to a total energy of 3000mj / cm 2 The samples were treated with LED light and then placed in 25℃, 90℃, 110℃, 85℃ / 85%RH and 110℃ / 90%RH environments for 1000h respectively. During this period, the samples were observed for the presence of bubbles and other phenomena. If there were bubbles, it was marked as ×, otherwise it was marked as √.

[0098] Table 3 Test results of aging resistance of various OCA optical adhesives

[0099] From the test results in Table 3, it can be seen that the OCA optical adhesive of the present invention has excellent aging resistance and does not cause bubble rebound or debonding in a high temperature and high humidity environment.

[0100] In summary, the light transmittance of the OCA optical adhesive of the present invention is above 90%, the haze is less than 1, and it can be kept in a high temperature and high humidity environment (temperature 100-150°C, humidity 60%-90%) for 1000 hours without any bubble rebound or debonding, showing excellent high temperature and high humidity resistance.

[0101] 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 it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, 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 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 polyol, polyisocyanate and hydroxyl-containing acrylate; the polyol includes polytetramethylene ether diol and polycaprolactone diol, and the polyisocyanate includes isophorone diisocyanate and hexamethylene diisocyanate.

2. The high temperature and high humidity resistant OCA optical adhesive according to claim 1, characterized in that: In the polyol, the molar ratio of the polytetramethylene ether diol to the polycaprolactone diol is 1:(0.5-2).

3. The high temperature and high humidity resistant OCA optical adhesive according to claim 1, characterized in that: In the polyisocyanate, the molar ratio of the isophorone diisocyanate to the hexamethylene diisocyanate is 1:(0.5-2).

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 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.

5. The high temperature and high humidity resistant OCA optical adhesive according to claim 1, characterized in that: 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.

6. 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.

7. 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 glass transition temperature of the soft monomer is -60 to -10°C; (2) the soft monomer includes at least one of ethyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, butyl acrylate and isooctyl acrylate; (3) the hard monomer comprises at least one of methyl acrylate, methyl methacrylate, isobornyl acrylate, ethyl methacrylate, styrene and acrylonitrile; (4) the functional monomer includes at least one of acrylic acid, acrylamide, N,N-dimethylacrylamide, hydroxyethyl acrylate and hydroxybutyl acrylate; (5) The crosslinking agent includes at least one of diethylene glycol diacrylate, triethylene glycol diacrylate, pentaerythritol triacrylate and trimethylolpropane triacrylate.

8. The method for preparing the high temperature and high humidity resistant OCA optical adhesive according to any one of claims 1 to 7, 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.

9. The preparation method according to claim 8, characterized in that: The thickness of the OCA optical adhesive is 50-300 μm.

10. Use of the high temperature and high humidity resistant OCA optical adhesive described in any one of claims 1 to 7 or the high temperature and high humidity resistant OCA optical adhesive prepared by the preparation method described in any one of claims 8 to 9 in display screens.

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