Ultraviolet light curable adhesive and method of making same

Abstract

The application provides a kind of ultraviolet light curing adhesive and its preparation method, adhesive includes first component and second component, by mass percentage, first component includes modified zirconia nanoparticles 55-85%, first monomer 10-40%, second component uses second monomer, the mass ratio of second monomer and the modified zirconia nanoparticles is 0.01-2:1.By the synergistic cooperation of specific proportion of modified zirconia nanoparticles, first monomer, the refractive index of ultraviolet light curing adhesive can reach more than 1.7, and ultraviolet light curing adhesive will not appear yellowing phenomenon;And by setting the mass ratio of second monomer and modified zirconia nanoparticles, the second monomer fills the cavity of nanoparticle in adhesive, so as to further improve the refractive index of adhesive.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of diffractive optical waveguide preparation, and particularly relates to a UV-curable adhesive and a preparation method thereof. BACKGROUND

[0002] The existing preparation method of the diffractive optical waveguide is generally as follows:

[0003] 1. A stamping master with a preset grating pattern is prepared.

[0004] 2. The grating pattern of the stamping master is transferred to a soft film by a nano-imprinting process to obtain a reverse pattern of the grating pattern on the soft film.

[0005] Specifically, the stamping master is uniformly spin-coated with a stamping adhesive, the soft film substrate is attached to the stamping master, pressure is applied to fill the stamping adhesive into the grating pattern of the stamping master, a reverse pattern of the grating pattern is obtained on the stamping adhesive, and the stamping adhesive with the reverse pattern of the grating pattern is transferred to the soft film substrate by UV curing and demolding to obtain the soft film with the reverse pattern of the grating pattern.

[0006] 3. The reverse pattern of the grating pattern on the soft film is transferred to a waveguide substrate by a nano-imprinting process to obtain the waveguide substrate with the grating pattern, thereby obtaining the diffractive optical waveguide.

[0007] Specifically, the waveguide substrate is spin-coated with an adhesion promoter and a product adhesive in sequence, the soft film with the reverse pattern of the grating pattern is attached to the product adhesive on the waveguide substrate, pressure is applied to fill the product adhesive into the reverse pattern of the grating pattern of the soft film, the grating pattern is obtained on the product adhesive, the soft film with the reverse pattern of the grating pattern is separated from the product adhesive with the grating pattern by UV curing and demolding, and the waveguide substrate with the grating pattern is obtained, thereby obtaining the diffractive optical waveguide.

[0008] The field of view angle of the diffractive optical waveguide is determined by the refractive index of the material. Under the same design logic, the higher the refractive index of the material, the larger the field of view angle. Therefore, it is urgent to improve the refractive index of the product adhesive used in the nano-imprinting process of the diffractive optical waveguide.

[0009] The existing product adhesive has the following problems:

[0010] The refractive index of the existing product adhesive is difficult to reach 1.7 or above, and the product adhesive has a problem of easy yellowing.

[0011] The filling capacity of the existing product adhesive for nano-scale structures is insufficient, resulting in a low structure transfer rate of the nano-imprinted product. SUMMARY

[0012] In order to overcome the defects of the prior art, the application provides a UV-curable adhesive and a preparation method thereof.

[0013] The present application realizes the technical scheme as follows:

[0014] The present application provides a kind of ultraviolet light curing adhesive, including first component and second component;

[0015] Wherein, by mass percentage, the first component includes modified zirconia nanoparticles 55-85%, first monomer 10-40%;

[0016] The second component uses second monomer;

[0017] The mass ratio of the second monomer to the modified zirconia nanoparticles is 0.01-2:1.

[0018] Further, by mass percentage, the modified zirconia nanoparticles are 60-80%, and the first monomer is 15-35%;

[0019] The mass ratio of the second monomer to the modified zirconia nanoparticles is 0.05-1.5:1.

[0020] Further, by mass percentage, the modified zirconia nanoparticles are 65-75%, and the first monomer is 20-30%;

[0021] The mass ratio of the second monomer to the modified zirconia nanoparticles is 0.1-1:1.

[0022] Further, the particle diameter of the modified zirconia nanoparticles is ≤50 nm. For example, the modified zirconia nanoparticles can be obtained from a modified zirconia nanoparticle dispersion. The modified zirconia nanoparticle dispersion can be ZP153 (modified zirconia nanoparticle content: 70%) from Japan Catalyst Co., Ltd.

[0023] The refractive index of the first monomer is ≥1.5.

[0024] Further, the first monomer uses a monomer containing a single or multiple benzene rings, or a monomer containing a vinyl group.

[0025] Further, the first monomer uses a monofunctional monomer.

[0026] The monofunctional monomer uses at least one of benzyl methacrylate (BZA), 2-phenoxyethyl acrylate (PHEA), o-phenylphenoxyethyl acrylate (OPPEA), and N-vinylpyrrolidone (NVP).

[0027] Further, the glass transition temperature of the second monomer is lower than 0℃, which ensures that the second monomer can smoothly enter the nanoparticle cavity in the adhesive, so that the second monomer fills the nanoparticle cavity in the adhesive.

[0028] Further, the second monomer is 2-ethylhexyl methacrylate (2-EHMA) and / or ethoxyethoxyethyl acrylate (EOEOEA).

[0029] Further, the first component further comprises a photo initiator 1-15% by mass percentage; preferably, the photo initiator is 1-10%, more preferably, the photo initiator is 1-5%.

[0030] The photo initiator comprises a first photo initiator and a second photo initiator;

[0031] The second photo initiator accounts for 0.1-7.5% by mass percentage in the first component; preferably, the second photo initiator accounts for 0.1-5% by mass percentage in the first component, more preferably, the second photo initiator accounts for 0.1-2.5% by mass percentage in the first component.

[0032] Further, the first photo initiator is at least one of benzil dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone (I184), 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173), 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropanone, 2-phenylbenz-2-dimethylamino-1-(4-morpholinobenzyl) butanone, 4,4'-bis(diethylamino) benzophenone, 2-isopropylthioxanthone, 2,4,6-trimethylbenzoyl phenyl phosphine, 2,4,6-trimethylbenzoyl diphenyl phosphine oxide (TPO) and 2,4,6-trimethylbenzoyl phenyl phosphinic acid ethyl ester.

[0033] Further, the second photo initiator is methyl benzoyl formate (MBF) and / or 4-methyl benzophenone (4-MBP).

[0034] Further, the first component further comprises an auxiliary agent;

[0035] The auxiliary agent accounts for ≤10% by mass percentage, preferably, the auxiliary agent accounts for ≤5% by mass percentage, more preferably, the auxiliary agent accounts for ≤1% by mass percentage.

[0036] Further, the auxiliary agent is at least one of BYK 378, BYK 333 and BYK 310 of BYK-Chemie.

[0037] Correspondingly, the application further provides a preparation method of the ultraviolet light curing adhesive, comprising the following steps:

[0038] The modified zirconium oxide nanoparticles, the first monomer and the second monomer are weighed according to the mass percentage;

[0039] The first monomer and the second monomer are stirred and mixed uniformly, then the modified zirconium oxide nanoparticles are added and stirred and mixed uniformly, to obtain the ultraviolet light curing adhesive.

[0040] Further, the photoinitiator is weighed in a mass percentage of 0.1-7.5%;

[0041] The first monomer, the second monomer and the photoinitiator are stirred and mixed uniformly, then the modified zirconium oxide nanoparticles are added and stirred and mixed uniformly, to obtain the ultraviolet light curing adhesive.

[0042] Further, the auxiliary agent is weighed in a mass percentage of ≤10%;

[0043] The first monomer, the second monomer, the photoinitiator and the auxiliary agent are stirred and mixed uniformly, then the modified zirconium oxide nanoparticles are added and stirred and mixed uniformly, to obtain the ultraviolet light curing adhesive.

[0044] Compared with the prior art, the technical scheme of the present application has the following beneficial effects:

[0045] The ultraviolet light curing adhesive provided by the present application comprises, in mass percentage, 55-85% of modified zirconium oxide nanoparticles and 10-40% of the first monomer, and the second component is the second monomer, and the mass ratio of the second monomer to the modified zirconium oxide nanoparticles is 0.01-2:1. Through the synergistic cooperation of the modified zirconium oxide nanoparticles and the first monomer in a specific ratio, the refractive index of the ultraviolet light curing adhesive can reach above 1.7, and the ultraviolet light curing adhesive does not appear yellowing phenomenon; and through setting the mass ratio of the second monomer to the modified zirconium oxide nanoparticles, the second monomer fills the cavities of the nanoparticles in the adhesive, so as to further improve the refractive index of the adhesive.

[0046] Preferably, the particle diameter of the modified zirconium oxide nanoparticles is ≤50 nm, and the refractive index of the first monomer is ≥1.5, further ensuring that the refractive index of the ultraviolet light curing adhesive can reach above 1.7.

[0047] Preferably, the first component of the ultraviolet light curing adhesive further comprises, in mass percentage, 1-15% of the photoinitiator; when the first monomer is a monofunctional monomer, a combination of the first photoinitiator and the second photoinitiator is adopted in a specific ratio, the first photoinitiator can be a conventional photoinitiator, the second photoinitiator is a crosslinking type photoinitiator, and the first photoinitiator, the second photoinitiator and the modified zirconium oxide nanoparticles synergistically cooperate, which can further improve the crosslinking degree of the adhesive after curing, so as to improve the weather resistance and solvent resistance of the adhesive, and at the same time, the system viscosity is not increased, so as to improve the structure transfer rate of the nanoimprint.

[0048] Preferably, the first component of the ultraviolet light curable adhesive further comprises a small amount of auxiliary agent in terms of mass percentage to ensure the coating surface of the adhesive on the waveguide substrate is flat. DETAILED DESCRIPTION

[0049] The technical solutions of the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application. Embodiment 1

[0050] The ultraviolet light curable adhesive of the present embodiment is composed of the following components in terms of mass:

[0051] Phenylphenoxyethyl acrylate (OPPEA) 22.8g;

[0052] Auxiliary agent (product model: BYK378) 0.2g;

[0053] 2-Ethylhexyl methacrylate (2-EHMA) 11.2g;

[0054] Methyl benzoylformate (MBF) 1g;

[0055] 2,4,6-Trimethylbenzoyl diphenyl phosphine oxide (TPO) 1g;

[0056] Modified zirconium oxide nanoparticle dispersion (product model: ZP153) 107.1g.

[0057] The preparation method of the ultraviolet light curable adhesive of the present embodiment is as follows:

[0058] Phenylphenoxyethyl acrylate (OPPEA), auxiliary agent (product model: BYK378), 2-ethylhexyl methacrylate (2-EHMA), methyl benzoylformate (MBF), 2,4,6-trimethylbenzoyl diphenyl phosphine oxide (TPO) and modified zirconium oxide nanoparticle dispersion (product model: ZP153) are respectively weighed according to the above mass.

[0059] Phenylphenoxyethyl acrylate (OPPEA), auxiliary agent (product model: BYK378), 2-ethylhexyl methacrylate (2-EHMA), methyl benzoylformate (MBF), 2,4,6-trimethylbenzoyl diphenyl phosphine oxide (TPO) are stirred uniformly, and then modified zirconium oxide nanoparticle dispersion (product model: ZP153) is added. The ultraviolet light curable adhesive is prepared by accelerating stirring in a centrifugal stirrer at 2000 rpm for 3 minutes. Embodiment 2

[0060] The ultraviolet light curing adhesive of the present embodiment is composed of the following components by mass:

[0061] Phenylphenoxyethyl acrylate (OPPEA) 22.8 g;

[0062] Auxiliary agent (product model BYK378) 0.2 g;

[0063] 2-Ethylhexyl methacrylate (2-EHMA) 75 g;

[0064] Methyl benzoylformate (MBF) 1 g;

[0065] 2,4,6-Trimethylbenzoyl diphenyl phosphine oxide (TPO) 1 g;

[0066] Modified zirconium oxide nanoparticle dispersion (product model: ZP153) 107.1 g.

[0067] The preparation method of the ultraviolet light curing adhesive of the present embodiment is as follows:

[0068] Phenylphenoxyethyl acrylate (OPPEA), auxiliary agent (product model BYK378), 2-ethylhexyl methacrylate (2-EHMA), methyl benzoylformate (MBF), 2,4,6-trimethylbenzoyl diphenyl phosphine oxide (TPO), and modified zirconium oxide nanoparticle dispersion (product model: ZP153) are respectively weighed according to the above mass.

[0069] Phenylphenoxyethyl acrylate (OPPEA), auxiliary agent (product model BYK378), 2-ethylhexyl methacrylate (2-EHMA), methyl benzoylformate (MBF), 2,4,6-trimethylbenzoyl diphenyl phosphine oxide (TPO), and modified zirconium oxide nanoparticle dispersion (product model: ZP153) are respectively weighed according to the above mass. Example 3

[0070] The ultraviolet light curing adhesive of the present embodiment is composed of the following components by mass:

[0071] Phenylphenoxyethyl acrylate (OPPEA) 22.8 g;

[0072] Auxiliary agent (product model BYK378) 0.2 g;

[0073] 2-Ethylhexyl methacrylate (2-EHMA) 11.2 g;

[0074] 4-Methyl benzophenone (4-MBP) 1 g;

[0075] 2,4,6-trimethylbenzoyl diphenyl phosphine oxide (TPO) 1 g;

[0076] Modified zirconia nanoparticle dispersion (product model: ZP153) 107.1 g.

[0077] The preparation method of the ultraviolet light curing adhesive of the present example is as follows:

[0078] The o-phenylphenoxyethyl acrylate (OPPEA), the auxiliary agent (product model BYK378), the 2-ethylhexyl methacrylate (2-EHMA), the 4-methylbenzophenone (4-MBP), the 2,4,6-trimethylbenzoyl diphenyl phosphine oxide (TPO) and the modified zirconia nanoparticle dispersion (product model: ZP153) are respectively weighed according to the above mass.

[0079] The o-phenylphenoxyethyl acrylate (OPPEA), the auxiliary agent (product model BYK378), the 2-ethylhexyl methacrylate (2-EHMA), the 4-methylbenzophenone (4-MBP), the 2,4,6-trimethylbenzoyl diphenyl phosphine oxide (TPO) are stirred uniformly, and then the modified zirconia nanoparticle dispersion (product model: ZP153) is added. The ultraviolet light curing adhesive can be prepared by accelerating stirring in a centrifugal stirrer at 2000 rpm for 3 minutes. Example 4

[0080] The ultraviolet light curing adhesive of the present example is composed of the following components by mass:

[0081] o-phenylphenoxyethyl acrylate (OPPEA) 22.8 g;

[0082] auxiliary agent (product model BYK378) 0.2 g;

[0083] ethoxyethoxyethyl acrylate (EOEOEA) 75 g;

[0084] methyl benzoylformate (MBF) 1 g;

[0085] 2,4,6-trimethylbenzoyl diphenyl phosphine oxide (TPO) 1 g;

[0086] Modified zirconia nanoparticle dispersion (product model: ZP153) 107.1 g.

[0087] The preparation method of the ultraviolet light curing adhesive of the present example is as follows:

[0088] OPPEA, additive (product model: BYK378), EOEOEA, MBF, TPO and modified zirconium oxide nanoparticle dispersion (product model: ZP153) were weighed according to the above quality respectively.

[0089] OPPEA, additive (product model: BYK378), EOEOEA, MBF, TPO were stirred uniformly, and then modified zirconium oxide nanoparticle dispersion (product model: ZP153) was added. The ultraviolet curing adhesive was prepared by stirring at 2000 rpm for 3 minutes in a centrifugal mixer.

[0090] Comparative Example 1

[0091] The ultraviolet curing adhesive of the present comparative example was composed of the following components by mass:

[0092] OPPEA 7.1 g;

[0093] Additive (product model: BYK378) 0.5 g;

[0094] 2-hydroxy-2-methyl-1-phenyl-1-propanone 0.8 g;

[0095] Diphenyl-(2,4,6-trimethylbenzoyl) phosphine oxide (TPO) 0.8 g;

[0096] Acetone 360 g;

[0097] 4,4'-dimercaptodiphenyl sulfide dimethyl methacrylate (high benzene ring, high sulfur content resin) 90 g.

[0098] The preparation method of the ultraviolet curing adhesive of the present comparative example:

[0099] OPPEA, additive (product model: BYK378), 2-hydroxy-2-methyl-1-phenyl-1-propanone, diphenyl-(2,4,6-trimethylbenzoyl) phosphine oxide (TPO), acetone and 4,4'-dimercaptodiphenyl sulfide dimethyl methacrylate were weighed according to the above quality respectively.

[0100] Phenylphenoxyethyl acrylate (OPPEA), an additive (product model number BYK378), 2-hydroxy-2-methyl-1-phenyl-1-propanone, diphenyl-(2,4,6-trimethylbenzoyl) phosphine oxide (TPO), and acetone were stirred uniformly, and then 4,4'-dithiobis (methyl methacrylate) was added. The UV-curable adhesive was prepared by accelerating stirring in a centrifugal mixer at 2000 rpm for 3 minutes.

[0101] Phenylphenoxyethyl acrylate (OPPEA) 22.8 g;

[0102] An additive (product model number BYK378) 0.2 g;

[0103] Methyl benzoylformate (MBF) 1 g;

[0104] Diphenyl-2,4,6-trimethylbenzoylphosphine oxide (TPO) 1 g;

[0105] Titanium oxide nanoparticle dispersion liquid TTP-1132 (manufacturer: Japan Daisen Chemical Industry Co., Ltd., titanium oxide solid content 40%, titanium oxide particle size 40 nm) 101.8 g.

[0106] The preparation method of the UV-curable adhesive of the present comparative example is as follows:

[0107] Phenylphenoxyethyl acrylate (OPPEA), an additive (product model number BYK378), methyl benzoylformate (MBF), diphenyl-2,4,6-trimethylbenzoylphosphine oxide (TPO), and titanium oxide nanoparticle dispersion liquid TTP-1132 were weighed according to the above mass.

[0108] Phenylphenoxyethyl acrylate (OPPEA), an additive (product model number BYK378), methyl benzoylformate (MBF), diphenyl-2,4,6-trimethylbenzoylphosphine oxide (TPO), and titanium oxide nanoparticle dispersion liquid TTP-1132 were stirred uniformly, and then the UV-curable adhesive was prepared by accelerating stirring in a centrifugal mixer at 2000 rpm for 3 minutes.

[0109] Comparative Example 2

[0110] The UV-curable adhesive of the present comparative example was composed of the following components by mass:

[0111] Phenylphenoxyethyl acrylate (OPPEA) 22.8 g;

[0112] An additive (product model number BYK378) 0.2 g;

[0113] 2-Ethylhexyl methacrylate (2-EHMA) 11.2 g;

[0114] 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173) 1 g;

[0115] 2,4,6-trimethylbenzoyl diphenyl phosphine oxide (TPO) 1 g;

[0116] Modified zirconium oxide nanoparticle dispersion (product model: ZP153) 107.1 g.

[0117] The preparation method of the ultraviolet curing adhesive of the present comparative example is as follows:

[0118] The o-phenylphenoxyethyl acrylate (OPPEA), the auxiliary agent (product model BYK378), the 2-ethylhexyl methacrylate (2-EHMA), the 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173), the 2,4,6-trimethylbenzoyl diphenyl phosphine oxide (TPO) and the modified zirconium oxide nanoparticle dispersion (product model: ZP153) are weighed according to the above mass respectively.

[0119] The o-phenylphenoxyethyl acrylate (OPPEA), the auxiliary agent (product model BYK378), the 2-ethylhexyl methacrylate (2-EHMA), the 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173), the 2,4,6-trimethylbenzoyl diphenyl phosphine oxide (TPO) are stirred uniformly, and then the modified zirconium oxide nanoparticle dispersion (product model: ZP153) is added. The ultraviolet curing adhesive can be prepared by accelerating stirring in a centrifugal mixer at 2000 rpm for 3 minutes.

[0120] Comparative Example 3

[0121] The ultraviolet curing adhesive of the present comparative example is composed of the following components by mass:

[0122] Trimethylolpropane triacrylate (3-functional acrylate monomer) 22.8 g;

[0123] Auxiliary agent (product model BYK378) 0.2 g;

[0124] 2-ethylhexyl methacrylate (2-EHMA) 11.2 g;

[0125] 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173) 1 g;

[0126] 2,4,6-trimethylbenzoyl diphenyl phosphine oxide (TPO) 1 g;

[0127] Modified zirconium oxide nanoparticle dispersion (product model: ZP153) 107.1 g.

[0128] The preparation method of the ultraviolet curing adhesive of the present comparative example is as follows:

[0129] The 3-hydroxymethyl propane triacrylate (3-functional acrylate monomer), the auxiliary (product model BYK378), the 2-ethylhexyl methacrylate (2-EHMA), the 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173), the 2,4,6-trimethylbenzoyl diphenyl phosphine oxide (TPO) and the modified zirconium oxide nanoparticle dispersion liquid (product model: ZP153) are weighed according to the above mass respectively.

[0130] The 3-hydroxymethyl propane triacrylate (3-functional acrylate monomer), the auxiliary (product model BYK378), the 2-ethylhexyl methacrylate (2-EHMA), the 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173), the 2,4,6-trimethylbenzoyl diphenyl phosphine oxide (TPO) and the modified zirconium oxide nanoparticle dispersion liquid (product model: ZP153) are weighed according to the above mass respectively.

[0131] Comparative Example 4

[0132] The ultraviolet curing adhesive of the present comparative example is composed of the following components by mass:

[0133] Phenylphenoxyethyl acrylate (OPPEA) 22.8g;

[0134] Auxiliary (product model BYK378) 0.2g;

[0135] Methyl benzoylformate (MBF) 1g;

[0136] 2,4,6-trimethylbenzoyl diphenyl phosphine oxide (TPO) 1g;

[0137] Modified zirconium oxide nanoparticle dispersion liquid (product model: ZP153) 107.1g.

[0138] The preparation method of the ultraviolet curing adhesive of the present comparative example is as follows:

[0139] The phenylphenoxyethyl acrylate (OPPEA), the auxiliary (product model BYK378), the methyl benzoylformate (MBF), the 2,4,6-trimethylbenzoyl diphenyl phosphine oxide (TPO) and the modified zirconium oxide nanoparticle dispersion liquid (product model: ZP153) are weighed according to the above mass respectively.

[0140] The o-phenylphenoxyethyl acrylate (OPPEA), the auxiliary agent (product model BYK378), the methyl benzoylformate (MBF), and the 2,4,6-trimethylbenzoyl diphenyl phosphine oxide (TPO) are stirred uniformly, and then the modified zirconium oxide nanoparticle dispersion liquid (product model: ZP153) is added. The ultraviolet curing adhesive is prepared by accelerating stirring in a centrifugal stirrer at 2000 rpm for 3 minutes.

[0141] The ultraviolet curing adhesives of Examples 1-4 and Comparative Examples 1-4 are applied to the nanoimprinting process of the diffractive optical waveguide as follows:

[0142] 1. A stamping master with a preset grating pattern is prepared.

[0143] 2. The grating pattern of the stamping master is transferred to a soft film by a nanoimprinting process, and a reverse pattern of the grating pattern is obtained on the soft film.

[0144] Specifically,

[0145] The stamping glue is uniformly spin-coated on the stamping master, the soft film substrate is attached to the stamping master, pressure is applied to fill the stamping glue into the grating pattern of the stamping master, a reverse pattern of the grating pattern is obtained on the stamping glue, and the stamping glue with the reverse pattern of the grating pattern is transferred to the soft film substrate by ultraviolet curing and demolding, thereby obtaining a soft film with the reverse pattern of the grating pattern.

[0146] 3. The reverse pattern of the grating pattern on the soft film is transferred to the waveguide substrate by a nanoimprinting process, thereby obtaining a waveguide substrate with a grating pattern, and a diffractive optical waveguide is obtained.

[0147] Specifically,

[0148] The glass wafer with surface adhesion treatment (i.e., the waveguide substrate) is placed on a glue spreader, and the ultraviolet curing adhesives of Examples 1-4 and Comparative Examples 1-4 are spin-coated after being added dropwise, respectively, thereby obtaining a uniform glue film layer with a nanoscale thickness. The soft film with the reverse pattern of the grating pattern is attached to the glue film layer, and a grating pattern is obtained on the glue film layer. Then, the glue film layer with the grating pattern is cured by ultraviolet light irradiation, and the soft film with the reverse pattern of the grating pattern is separated from the glue film layer with the grating pattern, thereby completing demolding. Thus, a waveguide substrate with a grating pattern is obtained, and a diffractive optical waveguide is obtained.

[0149] The performance of the ultraviolet curing adhesives of Examples 1-4 and Comparative Examples 1-4 in the nanoimprinting process is evaluated by refractive index, structure transfer rate, haze, weather resistance, solvent resistance, and UV aging performance, and the specific evaluation is as follows:

[0150] Refractive index test: the refractive index of the diffraction optical waveguide adhesive layer is tested by an ellipsometer to obtain the refractive index of the adhesive layer under the light wave of 532 nm wavelength (it should be noted that 532 nm wavelength is only an example, and other wavelengths can also be used).

[0151] Structure transfer rate test: the size (height and width) of the nanostructure (i.e. grating pattern) of the diffraction optical waveguide product is measured by a scanning electron microscope (SEM) or an atomic force microscope (AFM), and compared with the size (height and width) of the sub-template (inverse pattern of the grating pattern on the soft film), so as to obtain the corresponding structure transfer rate.

[0152] Haze test: the haze of the diffraction optical waveguide product is tested by a haze meter NDH2000.

[0153] Weather resistance test: the diffraction optical waveguide product is put into a constant temperature oven at 85℃, and after 240 hours, the change value of the thickness and the refractive index of the adhesive layer before and after the experiment is tested.

[0154] Solvent resistance test: the surface of the diffraction optical waveguide adhesive layer is wiped with a fine yarn dust-free cloth dipped with acetone, and the change value of the appearance, thickness and refractive index before and after wiping is recorded.

[0155] UV aging test: the diffraction optical waveguide product is put into a UV aging test box, and the color difference (△E) before and after the experiment is tested by a UV spectrophotometer to represent the yellowing degree of the adhesive. Experimental conditions: temperature 40℃; UV wavelength 340 nm; UV power 0.55 W / M 2 Experimental process: the radiation source is turned off for 4 hours after UV irradiation for 20 hours, and the cycle is repeated for 3 times.

[0156] The test results are shown in Table 1 below:

[0157] Table 1

[0158] The test results of the above examples 1-4 show that the refractive index of the nanoimprint ultraviolet curing adhesive provided by the present application can reach 1.7 or more, and has good transparency (low haze), excellent structure transfer rate, excellent weather resistance, excellent solvent resistance and excellent anti-UV yellowing performance.

[0159] From the test results of Comparative Example 1 and Example 1, it can be seen that:

[0160] The refractive index of the existing adhesive is low, and the yellowing degree is obvious after aging test. The adhesive of Example 1 of the present application cooperates the modified zirconium oxide nanoparticles and the first monomer in a specific ratio, so that the refractive index of the ultraviolet curing adhesive can reach 1.7 or more, and the ultraviolet curing adhesive has no yellowing phenomenon after aging test.

[0161] It can be seen from the test results of Comparative Example 2, Comparative Example 3 and Example 1 that:

[0162] It can be seen from Comparative Example 2 and Comparative Example 3 that when the multifunctional monomer is used to replace the monofunctional monomer, the crosslinking degree of the adhesive can be improved, and the weather resistance and solvent resistance of the crosslinking agent can be improved. However, the viscosity of the system is increased by increasing the crosslinking degree through the multifunctional monomer, which can cause the structure transfer rate of the nanoimprint to be reduced. In addition, the refractive index of the adhesive is reduced.

[0163] It can be seen from Comparative Example 2 and Example 1 that the photoinitiator in Example 1 of the present application is in the form of a combination of a conventional initiator and a crosslinking initiator, which cooperates with the modified zirconia nanoparticles. Compared with the case where a single conventional initiator cooperates with the modified zirconia nanoparticles, the crosslinking degree of the cured adhesive is improved, and the weather resistance and solvent resistance of the adhesive are improved. In addition, it can be seen from Comparative Example 3 that when the monomer is a monofunctional monomer, the adhesive in Example 1 of the present application can increase the crosslinking degree of the system without increasing the viscosity of the system, thereby improving the structure transfer rate of the nanoimprint, and improving the refractive index of the adhesive.

[0164] It can be seen from the test results of Comparative Example 4 and Example 1 that:

[0165] The adhesive in Comparative Example 4 has a low refractive index and a slightly high haze after curing due to the absence of the second monomer. However, by setting the mass ratio of the second monomer to the modified zirconia nanoparticles in Example 1 of the present application, the second monomer fills the cavities of the nanoparticles in the adhesive, thereby further improving the refractive index of the adhesive and reducing the haze.

[0166] The above examples are only used to illustrate the technical solutions of the present application and not to limit it. Although the present application has been described in detail with reference to the above examples, those skilled in the art can still modify or equivalently replace the specific embodiments of the present application. Any modification or equivalent replacement that does not deviate from the spirit and scope of the present application is within the scope of protection of the claims of the present application.

Claims

1. A UV-curable adhesive for nanoimprinting of diffractive waveguides, characterized in that, It consists of a first component and a second component; The first component, by mass percentage, consists of the following components: 55-85% modified zirconia nanoparticles, 10-40% first monomer, 1-15% photoinitiator, and ≤10% additives; The photoinitiator includes a first photoinitiator and a second photoinitiator; wherein the second photoinitiator accounts for 0.1-7.5% of the mass percentage of the first component; The second component is a second monomer; the mass ratio of the second monomer to the modified zirconia nanoparticles is 0.01-2:1; The first monomer is a monofunctional monomer; the monofunctional monomer is o-phenylphenoxyethyl acrylate; The first photoinitiator is 2,4,6-trimethylbenzoyl diphenylphosphine oxide, and the second photoinitiator is methyl benzoylformate and / or 4-methylbenzophenone; The auxiliary agent is at least one of BYK378, BYK333, and BYK310; The second monomer is 2-ethylhexyl methacrylate and / or ethoxyethoxyethyl acrylate.

2. The UV-curable adhesive according to claim 1, characterized in that, By mass percentage, the modified zirconia nanoparticles comprise 60-80%, and the first monomer comprises 15-35%. The mass ratio of the second monomer to the modified zirconia nanoparticles is 0.05-1.5:

1.

3. The UV-curable adhesive according to claim 1, characterized in that, By mass percentage, the modified zirconia nanoparticles comprise 65-75%, and the first monomer comprises 20-30%. The mass ratio of the second monomer to the modified zirconia nanoparticles is 0.1-1:

1.

4. The UV-curable adhesive according to claim 1, characterized in that, The modified zirconia nanoparticles have a particle diameter ≤50nm; the refractive index of the first monomer is ≥1.

5.

5. The method for preparing the ultraviolet-curable adhesive according to any one of claims 1-4, characterized in that, Includes the following steps: Weigh the modified zirconia nanoparticles, the first monomer, the second monomer, the photoinitiator, and the additives according to the stated mass percentage; The first monomer, the second monomer, the photoinitiator, and the additives were stirred and mixed evenly. Then, modified zirconia nanoparticles were added and stirred and mixed evenly to obtain a UV-curable adhesive.