Oil and water-proof OCA optical adhesive, preparation method and application thereof

Abstract

The application discloses an oil / water-proof OCA optical adhesive as well as a preparation method and application thereof, and belongs to the field of adhesives. The oil / water-proof OCA optical adhesive comprises a polymer obtained by polymerization of a mixture of hydroxyalkyl acrylate, alkyl acrylate monomer, crosslinking agent and chain transfer agent; the number of carbon atoms of the hydroxyalkyl group in the hydroxyalkyl acrylate is 2-4; and the number of carbon atoms of the alkyl group in the alkyl acrylate monomer is 1-6. The OCA optical adhesive controls the number of carbon atoms of the alkyl group of the polymer monomers, the hydroxyalkyl acrylate and the alkyl acrylate monomer, so that the OCA optical adhesive has good water / oil-proof property, has a light transmittance of more than 98% and a haze of less than 5% even after being soaked in water and oil for 7 days, and does not swell.

Description

Technical Field

[0001] This application relates to an oil- and water-resistant OCA optical adhesive, its preparation method, and its application, belonging to the field of adhesives. Background Technology

[0002] Optical adhesives (OCAs) are widely used in various electronic display devices, such as liquid crystal displays (LCDs), LED displays, and plasma displays. Display components are typically composed of multiple layers, and the gaps between these layers can cause light reflection, thereby reducing the brightness and contrast of the display. The main function of optical adhesives is to reduce the gaps between layers, thus improving optical properties.

[0003] With the continuous development of technology, people have higher requirements for the application range of optical adhesives. Many devices, such as mobile phones, watches, and wearable devices, use displays, and the performance of optical adhesives plays a decisive role in the performance of displays. It has been reported that sebum secreted by the sebaceous glands in human skin, when in direct contact with optical adhesives, will cause them to swell and fail over time. Simultaneously, many chemicals, when in contact with displays, can cause delamination, separation, and bubbling, mainly because the oils in these chemicals cause the OCA optical adhesive to swell. Furthermore, when OCA is exposed to environments with high water content (underwater, in rainy weather), it will inevitably swell and lose its adhesive properties, greatly affecting the optical performance of the display. Therefore, it is necessary to develop a waterproof and oil-resistant optical adhesive to overcome these problems. Summary of the Invention

[0004] According to one aspect of this application, an oil- and water-resistant OCA optical adhesive is provided. The OCA optical adhesive controls the number of alkyl carbons in the polymer monomers hydroxyalkyl acrylate and alkyl acrylate monomers, so that the OCA optical adhesive has good water and oil resistance. Even after being immersed in water and oil for 7 days, it still has a light transmittance of more than 98%, a haze of less than 5%, and no swelling occurs.

[0005] The oil- and water-resistant OCA optical adhesive described in this application comprises a polymer polymerized from a mixture of hydroxyalkyl acrylate, alkyl acrylate monomer, crosslinking agent, and chain transfer agent.

[0006] The hydroxyalkyl acrylate has 2-4 carbon atoms in its hydroxyalkyl group.

[0007] The alkyl acrylate monomer has 1-6 alkyl carbons.

[0008] Optionally, the alkyl acrylate monomer is selected from one or more of tert-butyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, phenyl methacrylate, cyclohexyl methacrylate, cyclohexyl acrylate, propyl methacrylate, n-hexyl acrylate, n-butyl acrylate, and 2-methylbutyl acrylate, and the alkyl acrylate monomer includes at least n-butyl methacrylate.

[0009] Optionally, the hydroxyalkyl acrylate is 4-hydroxybutyl acrylate (4-HBA) and / or 2-hydroxyethyl acrylate (2-HEA).

[0010] Optionally, the crosslinking agent is selected from one or more of N,N'-methylenebisacrylamide, methylbisacrylamide, N,N'-diallyl-L-tartaramide, tartaric acid bisacrylamide, hexamethylenebisacrylamide, N,N'-vinylbisacrylamide, and N,N'-(1,2-dihydroxyethylene)diacrylamide.

[0011] Optionally, the chain transfer agent includes one or more of carbon tetrabromide, alcohols, thiols, thiopropanetrimethoxysilane, and 1,4-bis(3-thiobutoxy)butane.

[0012] Optionally, the alcohol is ethanol and / or isopropanol.

[0013] Optionally, the thiol is selected from one or more of lauryl thiol, butyl thiol, tert-dodecyl thiol, ethanethiol, isooctyl thioacetate, 2-ethylhexyl thioacetate, 2-ethylhexyl thiopropionate, ethylene glycol dithioacetate, thiopropyltrimethoxysilane, and 1,4-bis(3-thiobutoxy)butane.

[0014] Optionally, the thiopropyltrimethoxysilane is 3-thiopropyltrimethoxysilane.

[0015] Optionally, the mass ratio of the hydroxyalkyl acrylate to the alkyl acrylate monomer is (1-5):1.

[0016] Optionally, the mass ratio of the hydroxyalkyl acrylate to the alkyl acrylate monomer is independently selected from any one of 1:1, 1.5:1, 2:1, 3:1, 4:1, 5:1 or a range between any two of the above.

[0017] Optionally, the mass ratio of the hydroxyalkyl acrylate to the crosslinking agent is (20-50):(0.5-1); preferably, the mass ratio of the crosslinking agent to the hydroxyalkyl acrylate is (30-40):0.5.

[0018] Optionally, the mass ratio of the hydroxyalkyl acrylate to the chain transfer agent is (20-50):(0.5-1); preferably, the mass ratio of the hydroxyalkyl acrylate to the chain transfer agent is (30-40):0.5.

[0019] Optionally, the mixture may also include antioxidants.

[0020] Optionally, the antioxidant is selected from one or more of tea polyphenols, butylated hydroxytoluene, tert-butylhydroquinone, and butylated hydroxyanisole.

[0021] Optionally, the mass ratio of the antioxidant to hydroxyalkyl acrylate is (1-2):(20-50); preferably, the mass ratio of the antioxidant to hydroxyalkyl acrylate is 1:(30-40).

[0022] This application also provides a method for preparing the oil- and water-resistant OCA optical adhesive, comprising the following steps:

[0023] The hydroxyalkyl acrylate, alkyl acrylate monomer, crosslinking agent, chain transfer agent, solvent and photoinitiator are mixed, degassed, and coated onto a release film and cured under ultraviolet light to obtain the OCA optical adhesive.

[0024] Optionally, the photoinitiator is selected from one or more of 1-hydroxycyclohexylbenzophenone, 2,2-dimethoxy-1,2-diphenylethyl-1-one, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propane-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)butanone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinylpropane-1-one, and 2-hydroxy-2-methyl-1-phenylpropane-1-one.

[0025] Optionally, the solvent is selected from one or more of water, acetone, methyl ethyl ketone, diethyl ether, chloroform, methyl acetate, ethyl acetate, propyl acetate, and butyl acetate.

[0026] Alternatively, the antioxidant can be mixed with hydroxyalkyl acrylate, alkyl acrylate monomer, crosslinking agent, chain transfer agent, solvent and photoinitiator.

[0027] Optionally, the amount of solvent and hydroxyalkyl acrylate added is (40-80) mL: (20-50) g; preferably, the amount of solvent and hydroxyalkyl acrylate added is (50-55) mL: (30-40) g.

[0028] Optionally, the mass ratio of the photoinitiator to the hydroxyalkyl acrylate is (0.5-2):(20-50); preferably, the mass ratio of the photoinitiator to the hydroxyalkyl acrylate is 1:(30-40).

[0029] Optionally, the mass ratio of the hydroxyalkyl acrylate to the alkyl acrylate monomer is (1-5):1.

[0030] Optionally, the mass ratio of the hydroxyalkyl acrylate to the alkyl acrylate monomer is independently selected from any one of 1:1, 1.5:1, 2:1, 3:1, 4:1, 5:1 or a range between any two of the above.

[0031] Optionally, the mass ratio of the hydroxyalkyl acrylate to the crosslinking agent is (20-50):(0.5-1); preferably, the mass ratio of the crosslinking agent to the hydroxyalkyl acrylate is (30-40):0.5.

[0032] Optionally, the mass ratio of the hydroxyalkyl acrylate to the chain transfer agent is (20-50):(0.5-1); preferably, the mass ratio of the hydroxyalkyl acrylate to the chain transfer agent is (30-40):0.5.

[0033] Optionally, the mixing temperature is 25-40°C.

[0034] Optionally, the thickness of the coating is 50-150 micrometers.

[0035] Optionally, the UV curing time is 1-2 hours.

[0036] The beneficial effects that this application can produce include:

[0037] The OCA optical adhesive provided in this application controls the number of alkyl carbons in the polymer monomers hydroxyalkyl acrylate and alkyl acrylate monomers, giving the OCA optical adhesive excellent water and oil resistance. Even after being immersed in water and oil for 7 days, it still has a light transmittance of over 98% and a haze of less than 5%, and no swelling occurs. Detailed Implementation

[0038] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0039] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0040] The raw material formula for the waterproof and oil-resistant optical adhesive is shown in the table below. Unless otherwise specified, the unit is g:

[0041] Table 1

[0042]

[0043] The preparation method is as follows: After the components in the formula are mixed evenly at 30℃, vacuum degassing is performed. The evenly mixed precursor solution is then coated onto the release film (coating thickness is 100 micrometers). After curing under ultraviolet light for 2 hours, waterproof and oil-proof OCA optical adhesive is obtained.

[0044] Oil and water resistance tests:

[0045] The prepared samples were placed in water and oil at room temperature for 7 days, and the swelling rate was tested. The swelling rate SR was calculated using the following formula:

[0046] SR = (W S -W0) / W S *100;

[0047] Among them, W S W0 represents the mass of the sample after swelling in water or oil, while W0 represents the mass of the sample before swelling in water or oil.

[0048] The oil resistance and water resistance of the optical adhesive samples were rated using the following criteria:

[0049] If no swelling or discoloration occurs after 7 days of swelling, the sample is rated 5. If swelling, discoloration, or bubbles are observed on the sample, it is rated 1.

[0050] Transmittance and haze tests:

[0051] The sample was coated onto a release film, cured under ultraviolet light, and the transmittance of the optical adhesive was tested on a transmittance and haze tester (model SGW-810).

[0052] The results of the oil resistance test are recorded in Table 2.

[0053] Table 2

[0054]

[0055] The results of the water resistance test are shown in Table 3.

[0056] Table 3

[0057]

[0058] As can be seen from the performance test results in Tables 2 and 3, Examples 1 and 2 both have good water and oil resistance. Even after being soaked in water and oil for 7 days, they still have a light transmittance of over 98% and a haze of less than 5%, and no swelling occurred. The selected monomers play a decisive role and can affect the oil resistance and water resistance of the optical adhesive.

[0059] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. An oil and water repellent OCA optical adhesive, characterized by, The polymer is polymerized from a mixture of a hydroxyalkyl acrylate, an alkyl acrylate monomer, a crosslinking agent, a chain transfer agent; The hydroxyalkyl acrylate has a carbon number of 2-4; The alkyl acrylate monomer has a carbon number of 1-6; The mass ratio of the hydroxyalkyl acrylate and the alkyl acrylate monomer is (1-5):1; The mass ratio of the hydroxyalkyl acrylate and the crosslinking agent is (20-50):(0.5-1); The mass ratio of the hydroxyalkyl acrylate and the chain transfer agent is (20-50):(0.5-1).

2. The oil and water repellent OCA optical glue according to claim 1, characterized in that, The alkyl acrylate monomer is selected from any one or more of t-butyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate, and propyl methacrylate, and the alkyl acrylate monomer at least includes n-butyl methacrylate. 3.The oil-and-water repellent OCA optical glue according to claim 1, characterized in that, The hydroxyalkyl acrylate is 4-hydroxybutyl acrylate and / or 2-hydroxyethyl acrylate.

4. The oil and water repellent OCA optical glue according to claim 1, characterized in that, The crosslinking agent is selected from any one or more of N,N'-methylenebisacrylamide, methylenebisacrylamide, N,N'-diallyl-L-tartaric amide, tartaric acid bisacrylamide, hexamethylenebisacrylamide, N,N'-vinylbisacrylamide, and N,N'-(1,2-dihydroxyethylene)bisacrylamide.

5. The oil and water repellent OCA optical glue according to claim 1, wherein, The chain transfer agent includes any one or more of carbon tetrabromide, an alcohol substance, a thiol substance, thio-propane trimethoxysilane, and 1,4-bis(3-thio-butoxy)butane; The thiol substance is selected from any one or more of lauryl mercaptan, butyl mercaptan, t-dodecyl mercaptan, ethyl mercaptan, thio-isooctyl acetate, thio-2-ethylhexyl acetate, thio-2-ethylhexyl propionate, ethylene glycol bis-thio-acetate, thio-propyl trimethoxysilane, and 1,4-bis(3-thio-butoxy)butane.

6. The oil and water repellent OCA optical glue according to claim 1, wherein, The mixture further includes an antioxidant; The antioxidant is selected from any one or more of tea polyphenol, butylated hydroxytoluene, t-butyl hydroquinone, and butylated hydroxyanisole; The mass ratio of the antioxidant and the hydroxyalkyl acrylate is (1-2):(20-50).

7. A method for preparing the oil and water repellent OCA optical adhesive according to any one of claims 1-6, characterized in that, The method includes the following steps: Mixing the hydroxyalkyl acrylate, the alkyl acrylate monomer, the crosslinking agent, the chain transfer agent, a solvent, and a photoinitiator, deaerating, and coating on a release film to obtain the OCA optical glue.

8. The method for preparing the oil- and water-resistant OCA optical adhesive according to claim 7, characterized in that, The photoinitiator is selected from any one or more of 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-1,2-diphenyl ethan-1-one, bis(2,4,6-trimethylbenzoyl)phenyl phosphine oxide, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propane-1-ketone, 2-benzyl-2-dimethylamino-1-(4-morpholinyl phenyl)butanone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinyl propane-1-ketone, and 2-hydroxy-2-methyl-1-phenyl propane-1-ketone. The solvent is selected from any one or more of water, acetone, methyl ethyl ketone, diethyl ether, chloroform, methyl acetate, ethyl acetate, propyl acetate, and butyl acetate. The mass ratio of the photoinitiator and the hydroxyalkyl acrylate is (0.5-2):(20-50); The adding amount of the solvent and the hydroxyalkyl acrylate is (40-80) mL:(20-50) g.

9. The method for preparing the oil- and water-resistant OCA optical adhesive according to claim 7, characterized in that, The antioxidant is mixed with the hydroxyalkyl acrylate, the alkyl acrylate monomer, the crosslinking agent, the chain transfer agent, the solvent and the photoinitiator.

10. The method for preparing the oil- and water-resistant OCA optical adhesive according to claim 7, characterized in that, The mixing temperature is 25-40℃; The ultraviolet curing time is 1-2h; The thickness of the blade coating is 50-150 microns.

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