Photocuring composition for imprinting and preparation method thereof

Abstract

The invention discloses a photocuring composition for imprinting and a preparation method of the photocuring composition. The photocuring composition comprises the following components: a polymerizable compound, an inorganic filler, a photoinitiator and an auxiliary agent, the polymerizable compound includes a polyester prepolymer having at least one (meth) acrylate functional group in an end chain; the polyester prepolymer has a structural unit # imgabs0 # shown in a formula I, wherein R1 and R2 are independently selected from a linear, branched or cyclic alkyl group with 1-20 carbon atoms, an alkyl ether group with 1-20 carbon atoms and an aromatic group with 5-60 carbon atoms respectively. The photocuring composition with good flexibility for imprinting provided by the invention is convenient for nanoimprinting and demolding, is suitable for R / VR, effectively improves the precision and integrity of a grating, and improves the display performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of materials, and particularly relates to a photocurable composition for imprinting and a preparation method thereof. Technical Background

[0002] Optical waveguide is the key optical technology solution for realizing the thin and light design of AR glasses and promoting them to the consumer market, and mass production is an important factor that needs to be solved. Nanoimprint technology is the core process of diffractive optical waveguides and an advanced optical display technology for mass production of diffractive optical waveguides. This precise process born in the semiconductor industry ensures that the production of diffractive optical waveguides can meet the requirements of consumer-level production capacity and yield.

[0003] Currently, this technology mainly includes thermal imprinting and ultraviolet imprinting. In ultraviolet imprinting, a very thin imprinting resin is first spin-coated (or dropped) on the transfer layer. After pressing down the template and waiting for the imprinting resin to completely fill the gaps of the template pattern, ultraviolet light is irradiated through the back of the template. After the imprinting resin is polymerized and cured into a shape, the template is removed, and then the pattern is transferred to the substrate through dry etching.

[0004] For ultraviolet imprinting resins, the most critical property is to be able to completely separate from the template when the mold is removed to ensure that the pattern on the template is completely transferred to the imprinting resin. However, during the peeling process, due to the action of adhesion and friction, stress is concentrated at the corner parts of the pattern, and the corners become the weakest parts of the imprinted pattern, and are prone to deformation and fracture. Based on this, the present invention provides a UV nanoimprint lithography resin with good demolding properties, and the prepared nano patterns have good integrity and high precision. Summary of the Invention

[0005] To solve the above technical problems, it includes the following components: a polymerizable compound, an inorganic filler, a photoinitiator, and an auxiliary agent; the polymerizable compound includes a polyester prepolymer with at least one (meth)acrylate functional group at the end chain; the polyester prepolymer has a structural unit shown in Formula I R1 and R2 are each independently selected from a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aromatic group having 5 to 60 carbon atoms, and n is the degree of polymerization. In the specific embodiments provided by the present invention, n is taken as 4.

[0006] Furthermore, the polyester prepolymer has a structural formula shown in Formula II In Formula II, m is any one of natural integers from 1 to 6; R1, R2, and n in Formula II are the same as R1, R2, and n in Formula I; * is the bonding site with the (meth)acrylate functional group, and R3 is selected from an acrylic acid group bonded with R2. When m is greater than 2, R3 includes an alkyl group having 1 to 8 carbon atoms. In the optimal solution of the present invention, m is selected from 1, 2, or 3.

[0007] Further, at least one of R1 and R2 is a straight-chain or branched-chain alkyl group having 1 to 20 carbon atoms. That is, in the preferred embodiment of the present invention, the case where both R1 and R2 are cyclic alkyl groups is not included.

[0008] The straight-chain or cyclic alkyl group having 1 to 20 carbon atoms includes any one of C 1-8 alkyl, C 3-8 saturated cycloalkyl; the aromatic group having 5 to 60 carbon atoms includes a benzene ring, and a polyaromatic group formed by any one or at least two of the connection methods of bonding, condensation, and C 1-5 alkyl bridging of.

[0009] Specifically, the above-mentioned straight-chain or cyclic alkyl group having 1 to 20 carbon atoms is preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, n-pentyl, sec-pentyl, neopentyl, n-hexyl, neohexyl, n-heptyl, n-octyl, cyclopropane, cyclobutane, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl; the above-mentioned C 6-50 aromatic hydrocarbon group is selected from phenyl, two benzene rings connected, condensed or connected by C 1-5 alkyl, and 3 to 4 benzene rings condensed with each other.

[0010] The above-mentioned C 6-50 aromatic hydrocarbon group is preferably benzene, naphthalene, anthracene, phenanthrene, biphenyl, diphenylmethane, diphenylethane, diphenylpropane.

[0011] Further, the weight ratio of the polymerizable compound, inorganic filler, photoinitiator, and auxiliary is (10-120):(0-80):(0.5-5):(0.1-70).

[0012] Further, the polymerizable compound further includes an acrylate monomer, and the acrylate monomer is selected from (meth)acrylate monomers containing at least one of an aromatic hydrocarbon group or an aliphatic hydrocarbon group, and the main chain of the acrylate monomer does not contain a polyether structural unit.

[0013] The (meth)acrylate monomer is a (meth)acrylate monomer containing C 1-12 alkyl or C 1-12 alkoxyalkyl, or a (meth)acrylate monomer containing 1 to 2 benzene ring structures substituted or unsubstituted by alkyl, hydroxyl or C 1-12 alkoxyalkyl.

[0014] The (meth)acrylate monomer is a mono(meth)acrylate, di(meth)acrylate, tri(meth)acrylate or tetra(meth)acrylate.

[0015] Preferably, those containing C 1-12 alkyl or C 1-12 alkoxy group of (meth)acrylate can be exemplified by: methyl (meth)acrylate, n-pentyl (meth)acrylate, isobutyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, isooctyl (meth)acrylate, ethylene glycol di(meth)acrylate, 1,3-propanediol di(meth)acrylate, butanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,12-dodecanediol (meth)acrylate, trimethylolpropane tri(meth)acrylate, glycerol tripropyl ether tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate.

[0016] (Meth)acrylate monomers containing 1-2 benzene ring structures substituted or unsubstituted by alkyl, hydroxyl or C 1-5 alkoxy group can be exemplified by: phenyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, 1,4-phenylene di(meth)acrylate, 2-phenoxyethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, 2-([1,1'-biphenyl]-2-yloxy)ethyl (meth)acrylate, 4,4'-diphenyl di(meth)acrylate, bisphenol di(meth)acrylate, 2-[4-(1-methyl-1-phenylethyl)phenoxy]ethyl (meth)acrylate, ethoxylated bisphenol di(meth)acrylate, phenoxybenzyl (meth)acrylate, biphenylmethanol (meth)acrylate.

[0017] Preferably, the weight ratio of the polymerizable compound, inorganic filler, photoinitiator, and auxiliary is (10-120):(0-80):(0.5-5):(0.1-70).

[0018] Furthermore, the inorganic filler is selected from surface-modified or unmodified inorganic nanoparticles. The inorganic filler is selected from surface-modified or unmodified inorganic nanoparticles. The inorganic nanoparticles are selected from any one or a combination of ZrO2, TiO2, ZnS, ZnO, CeO2, GeO2, Ta2O5, Bi4Ti3O2, Nb2O5, HfO2, SnO2, MoO3, Sb2O3, Sb2O5, Nd2O3.

[0019] Preferably, the particle size range of the nanoparticles is 10nm - 50nm.

[0020] Examples of surface modification methods include esterification method, coupling agent method, surface grafting method, organic matter adsorption coating method, etc. For example, the inorganic nanoparticles can be surface-modified with a silane coupling agent to improve their compatibility and dispersibility with the matrix resin material. In this example, inorganic nanoparticles without surface modification are selected.

[0021] Further, the photoinitiator is selected from any one or a combination of α-hydroxy ketone initiators, benzoin initiators, acylphosphine oxide initiators, acetophenone initiators, morpholinone initiators, naphthalimide photoinitiators, oxime ester photoinitiators, carbazolyl photoinitiators.

[0022] Preferably, the photoinitiator is selected from any one or a combination of at least two of α-hydroxy ketone initiators, benzoin initiators, acylphosphine oxide initiators, acetophenone initiators, morpholinone initiators, naphthalimide photoinitiators, oxime ester photoinitiators, carbazolyl photoinitiators.

[0023] In the present invention, the additives include any one or a combination of at least two of surfactants, solvents, adhesion promoters, defoamers.

[0024] Preferably, the surfactant is selected from at least one of polyether-modified polydimethylsiloxane, polyester-modified polydimethylsiloxane containing polyacrylate functional groups, polyether-modified polydimethylsiloxane containing hydroxyl groups, acryloyloxy-modified silane polymers.

[0025] Preferably, the solvent is selected from one or a mixture of esters, alcohols, ethers, ketones, and benzenes. The ester solvents are selected from: ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, methoxybutyl acetate, 3-methoxybutyl acetate, methoxypentyl acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, triethylene glycol monomethyl ether acetate, triethylene glycol monoethyl ether acetate, 3-methyl-3-methoxybutyl acetate, ethylene glycol diacetate, 1,3-butanediol diacetate, 1,6-hexanediol diacetate, cyclohexanol acetate; the alcohols are selected from: methanol, ethanol, cyclohexanol, ethylene glycol, propylene glycol, butanediol, diethylene glycol, dipropylene glycol, triethylene glycol; the ethers are selected from: ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monomethyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether; the ketones are selected from: acetone, methyl amyl ketone, methyl isopropyl ketone, methyl isopentyl ketone, diisopropyl ketone, diisobutyl ketone, methyl isobutyl ketone, cyclohexanone, ethyl amyl ketone, methyl butyl ketone, methyl hexyl ketone; the benzenes are selected from: any one of toluene and xylene or a combination of at least two of them.

[0026] In a second aspect, the present invention provides a method for preparing a photocurable composition for imprinting, comprising the following steps:

[0027] S1: Put the polymerizable compound, inorganic filler, photoinitiator, and additive into a reaction kettle and stir, control the temperature between 20°C and 50°C, stir and mix evenly to obtain a mixed material;

[0028] S2: Filter the mixed material obtained in step S1 with a filter element to obtain a photocurable composition for imprinting.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] The photocurable composition for imprinting provided by the present invention has good fluidity and flexibility before and after curing. During the demolding process of the imprinting adhesive after curing, through good flexibility, it resists the adhesion force and friction force during the mold demolding process, avoids the deformation and brittle fracture of the pattern, and maintains the integrity and accuracy of the nano-pattern. Specific Embodiments

[0031] The embodiments of the present invention will be described in detail below in conjunction with the examples. However, those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. For those not specified in the examples, the operations are carried out under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments not specified by the manufacturer can all be obtained as conventional products through commercial purchase.

[0032] Examples 1-8 and Comparative Examples 1-4:

[0033] The component polyester prepolymers used in Examples 1-8 and Comparative Examples 1-4 are shown in Table 1 below:

[0034] Table 1 Component Table

[0035]

[0036]

[0037] The component parts by weight of Examples 1-8 and Comparative Examples 1-4 are shown in Table 2 below:

[0038] Table 2 Component Weight Fraction Table

[0039]

[0040]

[0041] Prepare the UV curable composition for imprinting by the following preparation steps with the components of the above Examples 1-8 and Comparative Examples 1-4:

[0042] S1: Put the polyester prepolymer, acrylate monomer, ZrO2, photoinitiator, surfactant, and solvent into a reaction kettle and stir. Control the temperature at 30 °C, the stirring speed at 1500 rpm, and the stirring time at 4 h.

[0043] Obtain a mixed material;

[0044] S2: Filter the mixed material obtained in step S1 with a filter element with a pore size of 0.3 μm to obtain the UV curable composition for imprinting.

[0045] Performance detection:

[0046] The UV curable compositions for imprinting prepared in Examples 1-8 and Comparative Examples 1-4 are numbered 1-12 respectively and subjected to the following detections:

[0047] 1) Thermal shrinkage rate: Coat 5 μm on a quartz substrate using inkjet printing technology. After drying the substrate in a vacuum drying oven for 30 minutes, pre-bake it on a vacuum hot plate at 80 °C for 1 minute, and then put it into a UV curing machine at about 2000 mJ / cm 2Irradiate the organic-inorganic composite material with high-intensity light to cure it and prepare a film sample. Measure the shrinkage rate by thermal film shrinkage measurement at 150 °C for 30 min.

[0048] 2) Elongation at break: Measure its elongation at break with a tensile testing machine.

[0049] 3) Adhesion (to glass): Test according to the method in Standard STM Comparative Example 3359.

[0050] 4) Surface tension: Measure the surface tension with a contact angle measuring instrument. Measure each sample five times and take the average value.

[0051] 5) Observation and evaluation of surface state: Good: No defects such as protrusions and brittle fractures; General: A small number of defects such as protrusions and brittle fractures; Poor: A large number of defects such as protrusions and brittle fractures.

[0052] The test results are shown in Table 3 below:

[0053] Table 3

[0054]

[0055] As can be seen from Table 3 above, compared with Comparative Examples 1-4, Examples 1-8 have a lower volume shrinkage rate. Low volume shrinkage is very important for maintaining the integrity of the pattern. The surface energy of the system is significantly reduced and at the same time it has good adhesion to glass. Low surface energy does not cause adhesion to the template during the demolding process, which is conducive to smooth demolding. The nano-patterns prepared with the curing combination provided in the examples have higher integrity and accuracy, which is more conducive to improving the display performance of R / VR devices.

[0056] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A photocurable composition for imprinting, characterized in that, It comprises the following components: a polymerizable compound, an inorganic filler, a photoinitiator, and an auxiliary agent; the polymerizable compound includes a polyester prepolymer having at least one (meth)acrylate functional group at the end chain; the polyester prepolymer has a structural unit represented by Formula I R1 and R2 are each independently selected from a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and an aromatic group having 5 to 60 carbon atoms.

2. The photocurable composition for imprinting according to claim 1, wherein The polyester prepolymer has the structural formula shown in Formula II In Formula II, m is any one of the natural integers from 1 to 6; R1, R2, and n in Formula II are the same as R1, R2, and n in Formula I; * is the bonding site with the (meth)acrylate functional group, R3 is selected from the acrylic acid group bonded with R2, and when m is greater than 2, R3 includes an alkyl group having 1 to 8 carbon atoms.

3. The photocurable composition for imprinting according to claim 2, wherein At least one of R1 and R2 is a straight-chain or branched alkyl group having 1 to 20 carbon atoms.

4. The photocurable composition for imprinting according to claim 2, wherein The straight-chain or cyclic alkyl group having 1 to 20 carbon atoms includes any one of alkyl groups of C 1-8 and saturated cycloalkyl groups of C 3-8 ; the aromatic group having 5 to 60 carbon atoms includes a benzene ring, and a polyaromatic group formed by any one or two of the connection methods of bonding, condensation, or an alkyl bridge of C 1-5 .

5. The photocurable composition for imprinting according to claim 1, characterized in that, The polymerizable compound further includes an acrylate monomer, and the acrylate monomer is selected from (meth)acrylate monomers containing at least one of an aromatic hydrocarbon group or an aliphatic hydrocarbon group, and the main chain of the acrylate monomer does not contain a polyether structural unit.

6. The photocurable composition for imprinting according to claim 1, characterized in that, The weight ratio of the polymerizable compound, inorganic filler, photoinitiator, and auxiliary is (10-120):(0-80):(0.5-5):(0.1-70).

7. The photocurable composition for imprinting according to claim 1, wherein The inorganic filler is selected from surface-modified or unmodified inorganic nanoparticles, and the inorganic nanoparticles are selected from any one or a combination of at least two of ZrO2, TiO2, ZnS, ZnO, CeO2, GeO2, Ta2O5, Bi4Ti3O2, Nb2O5, HfO2, SnO2, MoO3, Sb2O3, Sb2O5, Nd2O3.

8. The photocurable composition for imprinting according to claim 1, wherein The photoinitiator is selected from any one or a combination of at least two of α-hydroxy ketone initiators, benzoin initiators, acylphosphine oxide initiators, acetophenone initiators, morpholinone initiators, naphthalimide photoinitiators, oxime ester photoinitiators, and carbazolyl photoinitiators.

9. The photocurable composition for imprinting according to claim 1, wherein The auxiliary includes any one or a combination of at least two of surfactants, solvents, adhesion promoters, and defoamers.

10. A method for preparing a photocurable composition for imprinting according to any one of claims 1 to 9, characterized in that, It includes the following steps: S1: Put the polymerizable compound, inorganic filler, photoinitiator, and auxiliary into a reaction kettle and stir, control the temperature between 20°C and 50°C, and stir and mix evenly to obtain a mixed material; S2: Filter the mixed material obtained in step S1 with a filter element to obtain a photocurable composition for imprinting.

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