Optical thin film material and preparation method and application thereof

Abstract

The invention relates to an optical thin film material and a preparation method and application thereof, and belongs to the technical field of optical materials, and the optical thin film material comprises the following components in parts by weight: 80-100 parts of acrylate copolymer and 5-10 parts of filler; the acrylate copolymer is prepared by carrying out polymerization reaction on butyl methacrylate, hydroxyethyl methylacrylate and gamma-methacryloxy propyl trimethoxy silane, and the acrylic acid ester copolymer is obtained by carrying out polymerization reaction on the butyl methacrylate, the hydroxyethyl methylacrylate and the gamma-methacryloxy propyl trimethoxy silane; the filler is a silicon dioxide doped zinc oxide composite material. According to the invention, butyl methacrylate, hydroxyethyl methylacrylate and gamma-methacryloxypropyltrimethoxysilane are subjected to a polymerization reaction to prepare an acrylate copolymer with good optical performance, and a silicon dioxide doped zinc oxide composite material is added into the acrylate copolymer as a filler; the aging resistance of the acrylate copolymer is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical materials, and in particular relates to an optical film material and a preparation method and application thereof. Background Art

[0002] Optical film is a functional material composed of thin layered media. It can precisely control the light propagation path by controlling the reflection, transmission, polarization and other characteristics of light. It is widely used in the fields of optical instruments, display devices and photovoltaic devices. At present, the main optical film is polyethylene terephthalate (PET) film. Compared with other types of optical films, PET film has higher purity and higher tensile strength. At the same time, PET has better dimensional stability, lower hygroscopicity, can better retain its physical properties in a wide temperature range, and has better optical properties. Therefore, in the current market, PET optical film is more widely used. Although PET film for optical use has many advantages, the rapidly developing new energy industry and display industry have an increasing demand for optical films with excellent performance.

[0003] In the prior art, acrylic polymer films are used to improve the optical properties of PET films due to their excellent transparency and designability. However, in order to achieve complete transparency enhancement, the refractive index of the polymer needs to be as low as possible, so the selection of polymer materials is particularly important. In addition, the aging resistance of acrylic polymer films is poor, so there is room for improvement. Summary of the invention

[0004] In view of the above situation, in order to overcome at least part of the defects of the above-mentioned prior art, the present invention provides an optical thin film material and a preparation method and application thereof.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows: The first aspect of the present invention provides an optical film material, which comprises the following components in parts by weight: 80-100 parts of an acrylate copolymer and 5-10 parts of a filler; the acrylate copolymer is prepared by polymerization of butyl methacrylate, hydroxyethyl methacrylate and γ-methacryloxypropyltrimethoxysilane; and the filler is a silicon dioxide-doped zinc oxide composite material.

[0006] In some embodiments, the filler is prepared from nano zinc oxide and tetraethyl orthosilicate.

[0007] A second aspect of the present invention provides a method for preparing an optical thin film material, comprising: Take the acrylic acid ester copolymer and add it into ethanol, adjust the pH value to 4-5, add deionized water, react at 40-50° C. for 20-30 minutes, add filler, and continue to react for 8-10 hours to obtain an optical film material.

[0008] In some embodiments, the method for preparing the acrylate copolymer comprises: Butyl methacrylate, hydroxyethyl methacrylate and γ-methacryloxypropyltrimethoxysilane were added to ethanol, and azobisisobutyronitrile was added. The mixture was fully mixed under an inert atmosphere, and the mixture was reacted at 60-70° C. for 4-8 hours to obtain an acrylate copolymer.

[0009] In some embodiments, the mass ratio of butyl methacrylate, hydroxyethyl methacrylate and γ-methacryloxypropyltrimethoxysilane is 100:(60-80):(1-3).

[0010] In some embodiments, the method for preparing the filler comprises: Zinc oxide is added to ethanol, and then ethyl orthosilicate and deionized water are added, and the mixture is stirred at 30-40° C. for 20-30 hours. After the stirring is completed, the mixture is centrifugally dried to obtain a filler.

[0011] In some embodiments, the molar ratio of the nano zinc oxide to tetraethyl orthosilicate is 1:(0.5-1).

[0012] In some embodiments, the molar ratio of ethyl orthosilicate to deionized water is 1:(4-6).

[0013] A third aspect of the present invention provides an application of an optical film material, wherein the optical film material is coated on the surface of a PET film to prepare a composite optical film.

[0014] The beneficial effects achieved by the present invention are as follows: The invention prepares an acrylate copolymer with good optical properties through polymerization reaction of butyl methacrylate, hydroxyethyl methacrylate and gamma-methacryloxypropyltrimethoxysilane, and adds a silicon dioxide-doped zinc oxide composite material as a filler into the acrylate copolymer to improve the aging resistance of the acrylate copolymer. DETAILED DESCRIPTION

[0015] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0016] Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described herein may be applied to the present invention. The preferred implementation methods and materials described herein are for demonstration purposes only and are not intended to limit the content of this application.

[0017] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0018] In view of the deficiencies in the prior art mentioned in the background technology, the first aspect of the embodiment of the present invention proposes an optical film material, which includes the following components in parts by weight: 80-100 parts of an acrylate copolymer and 5-10 parts of a filler; the acrylate copolymer is prepared by polymerization reaction of butyl methacrylate, hydroxyethyl methacrylate and γ-methacryloxypropyltrimethoxysilane; and the filler is a silica-doped zinc oxide composite material.

[0019] In the acrylate copolymer, the butyl group of butyl methacrylate can provide the polymer with better flexibility and film-forming properties, and the hydroxyl group of hydroxyethyl methacrylate and the butyl group of butyl methacrylate can inhibit phase separation by forming a random or alternating structure, thereby avoiding the increase of haze caused by microscopic phase separation, thereby making the acrylate copolymer have high transparency. In addition, the double bond of γ-methacryloxypropyltrimethoxysilane can also participate in the copolymerization reaction, and a methoxysilane group can be introduced into the main chain of the acrylate copolymer.

[0020] Zinc oxide, as an inorganic light stabilizer, has good ultraviolet absorption properties. However, direct addition of zinc oxide to acrylate copolymers will cause degradation of the acrylate copolymers and reduce the service life of the acrylate copolymers. By using a silica-doped zinc oxide composite material, direct contact between zinc oxide and the acrylate copolymer can be avoided, thereby increasing the service life of the acrylate copolymer. At the same time, silica contains a large amount of hydroxyl groups, which can enhance the dispersibility of zinc oxide in the acrylate copolymer and avoid light scattering caused by particle agglomeration, thereby maintaining the optical properties of the polymer. In addition, since methoxysilane groups are introduced into the main chain of the acrylate copolymer, the hydroxyl groups of silica can combine with silanols formed by hydrolysis of methoxysilane groups through a condensation reaction, thereby improving the binding force between zinc oxide and the polymer and enhancing the mechanical properties of the optical film material.

[0021] Preferably, the optical film material includes the following components in parts by weight: 100 parts of acrylic copolymer and 10 parts of filler. Experiments show that the optical film material has high transmittance and transmittance after aging, and has good optical properties and aging resistance.

[0022] In some embodiments, the filler is prepared from nano zinc oxide and tetraethyl orthosilicate. The smaller size of nano zinc oxide makes it almost non-scattering visible light, so the use of nano zinc oxide can make the acrylate copolymer maintain good light transmittance. At the same time, since it is difficult to fully combine silicon dioxide by directly adding nano zinc oxide to the two, tetraethyl orthosilicate can be used to embed nano zinc oxide into amorphous silicon dioxide through hydrolysis condensation, so that the nano zinc oxide and the acrylate copolymer can be fully separated.

[0023] A second aspect of the present invention provides a method for preparing an optical thin film material, comprising: Take the acrylate copolymer and add it to ethanol, adjust the pH value to 4-5, add deionized water, react at 40-50°C for 20-30 minutes, add filler, and continue to react for 8-10 hours to obtain an optical film material. Since methoxysilane groups are introduced into the acrylate copolymer, the methoxysilane groups are hydrolyzed under acidic conditions with a pH value of 4-5 to generate silanols, and then after the filler is added, the hydroxyl groups of silicon dioxide in the filler can be combined with the silanols formed by the hydrolysis of the methoxysilane groups through a condensation reaction, thereby preparing an optical film material.

[0024] In some embodiments, the method for preparing an acrylate copolymer comprises: Take butyl methacrylate, hydroxyethyl methacrylate and γ-methacryloxypropyl trimethoxysilane and add them to ethanol, add azobisisobutyronitrile, mix them thoroughly under an inert atmosphere, and react at 60-70°C for 4-8 hours to obtain an acrylate copolymer. Among them, ethanol as a polar solvent has good solubility for butyl methacrylate, hydroxyethyl methacrylate and γ-methacryloxypropyl trimethoxysilane, and azobisisobutyronitrile as a thermal initiator can initiate free radical chain polymerization of the monomers. Since γ-methacryloxypropyl trimethoxysilane contains double bonds and methoxysilane groups, the double bonds can participate in the copolymerization reaction to introduce the methoxysilane groups into the main chain of the acrylate copolymer, thereby providing reaction sites for the condensation reaction of the filler. The inert atmosphere can exclude oxygen in the reaction system, thereby preventing chain termination reactions and ensuring polymerization efficiency. The inert atmosphere can be a nitrogen atmosphere.

[0025] In some embodiments, the mass ratio of butyl methacrylate, hydroxyethyl methacrylate and γ-methacryloxypropyltrimethoxysilane is 100:(60-80):(1-3). Since the hydroxyl group of hydroxyethyl methacrylate and the butyl ester group of butyl methacrylate can improve the transparency of the acrylate copolymer by forming a random or alternating structure, too little addition will reduce the transparency of the acrylate copolymer. However, the hydroxyl group of hydroxyethyl methacrylate will increase the hydrophilicity of the acrylate copolymer. Too much addition will cause the hydrophilicity of the acrylate copolymer to be too high, affecting its service life. At the same time, the addition of γ-methacryloxypropyltrimethoxysilane can introduce methoxysilane groups into the main chain of the acrylate copolymer, providing reaction sites for the condensation reaction of the filler. Too little addition will result in insufficient number of silanols to bond the filler, reducing the bonding force between the filler and the acrylate copolymer. However, too much addition of γ-methacryloxypropyltrimethoxysilane will cause light scattering and reduce the optical properties of the acrylate copolymer. Therefore, the mass ratio of butyl methacrylate, hydroxyethyl methacrylate and γ-methacryloxypropyltrimethoxysilane needs to be set to 100:(60-80):(1-3).

[0026] In some embodiments, the method for preparing the filler comprises: Take nano zinc oxide and add it to ethanol, add tetraethyl orthosilicate and deionized water, stir at 30-40°C for 20-30h, and then centrifuge and dry to obtain filler. With tetraethyl orthosilicate as the silicon source, tetraethyl orthosilicate can be hydrolyzed in the ethanol-water system to generate silicic acid, and the generated silicic acid can nucleate on the surface of nano zinc oxide, thereby preparing a silicon dioxide-doped zinc oxide composite material, which is the filler. Among them, stirring for 20-30h can make tetraethyl orthosilicate fully hydrolyzed and condensed, so that a complete silicon dioxide layer can be formed on the surface of nano zinc oxide.

[0027] In some embodiments, the molar ratio of nano zinc oxide to tetraethyl orthosilicate is 1:(0.5-1). It is understandable that tetraethyl orthosilicate is a silicon source, and its addition amount will affect the yield of silicon dioxide. Too little addition of tetraethyl orthosilicate will result in the silicon dioxide layer being unable to fully cover the nano zinc oxide, thereby failing to completely separate the nano zinc oxide and the acrylate copolymer. Too much addition of tetraethyl orthosilicate will make the thickness of the silicon dioxide layer too large, reducing the ultraviolet absorption effect of the nano zinc oxide. Therefore, it is necessary to set the molar ratio of nano zinc oxide to tetraethyl orthosilicate to 1:(0.5-1).

[0028] In some embodiments, the molar ratio of ethyl orthosilicate to deionized water is 1:(4-6). It is understandable that the hydrolysis of ethyl orthosilicate requires the consumption of deionized water, so the amount of deionized water added controls the degree of hydrolysis and the hydrolysis reaction rate of ethyl orthosilicate. Too little deionized water will lead to incomplete hydrolysis, and too much deionized water will lead to the generation of a large amount of free silicon dioxide. Therefore, the molar ratio of ethyl orthosilicate to deionized water needs to be set to 1:(4-6).

[0029] The third aspect of the present invention provides an application of an optical film material, wherein the optical film material is coated on the surface of a PET film to obtain a composite optical film. Using the PET film as a substrate for the composite optical film can provide good mechanical properties and a high transmittance, and coating the optical film material on the surface of the PET film can improve the transmittance and durability of the PET film.

[0030] The present invention will be further described below by way of specific embodiments.

[0031] The experimental methods in the following examples are conventional methods unless otherwise specified; the experimental materials used in the following examples are purchased from commercial channels unless otherwise specified.

[0032] Example 1 Butyl methacrylate, hydroxyethyl methacrylate and γ-methacryloxypropyltrimethoxysilane were added to ethanol in a mass ratio of 100:60:1, and azobisisobutyronitrile was added, the mixture was fully mixed under an inert atmosphere, and the mixture was reacted at 60° C. for 4 h to obtain an acrylate copolymer; Zinc oxide was added to ethanol, and tetraethyl orthosilicate and deionized water were added, the molar ratio of nano zinc oxide to tetraethyl orthosilicate was 1:0.5, and the molar ratio of tetraethyl orthosilicate to deionized water was 1:4, and the mixture was stirred at 30° C. for 20 h, and then centrifuged and dried to obtain a filler; 80 parts of acrylate copolymer were added to ethanol by weight, the pH value was adjusted to 4, 8 parts of deionized water were added, the reaction was carried out at 40° C. for 20 min, 5 parts of filler were added, and the reaction was continued for 8 h to obtain an optical film material.

[0033] Example 2 Butyl methacrylate, hydroxyethyl methacrylate and γ-methacryloxypropyltrimethoxysilane were added to ethanol in a mass ratio of 100:80:3, and azobisisobutyronitrile was added, the mixture was fully mixed under an inert atmosphere, and the mixture was reacted at 70° C. for 8 h to obtain an acrylate copolymer; Zinc oxide was added to ethanol, and tetraethyl orthosilicate and deionized water were added, the molar ratio of nano zinc oxide to tetraethyl orthosilicate was 1:1, and the molar ratio of tetraethyl orthosilicate to deionized water was 1:6, and the mixture was stirred at 40° C. for 30 h, and then centrifuged and dried to obtain a filler; 100 parts of acrylate copolymer were added to ethanol by weight, the pH value was adjusted to 5, 20 parts of deionized water were added, the reaction was carried out at 50° C. for 30 minutes, 10 parts of filler were added, and the reaction was continued for 8-10 hours to obtain an optical film material.

[0034] Example 3 The method is consistent with Example 1, except that when preparing the acrylic ester copolymer, the mass ratio of butyl methacrylate, hydroxyethyl methacrylate and γ-methacryloxypropyltrimethoxysilane is 100:65:1.

[0035] Example 4 The method is consistent with Example 1, except that when preparing the acrylic ester copolymer, the mass ratio of butyl methacrylate, hydroxyethyl methacrylate and γ-methacryloxypropyltrimethoxysilane is 100:70:1.

[0036] Example 5 The method is consistent with Example 1, except that when preparing the acrylic ester copolymer, the mass ratio of butyl methacrylate, hydroxyethyl methacrylate and γ-methacryloxypropyltrimethoxysilane is 100:75:1.

[0037] Example 6 The method is consistent with Example 1, except that when preparing the acrylic ester copolymer, the mass ratio of butyl methacrylate, hydroxyethyl methacrylate and γ-methacryloxypropyltrimethoxysilane is 100:80:1.

[0038] Comparative Example 1 The method is consistent with Example 1, except that the silicon dioxide-doped zinc oxide composite material is not prepared, and nano zinc oxide is used as filler instead of the silicon dioxide-doped zinc oxide composite material.

[0039] Comparative Example 2 A PET film not coated with an optical film material was selected as Comparative Example 2.

[0040] Performance tests were performed on Examples 1-6 and Comparative Examples 1 and 2. In Examples 1-6 and Comparative Example 1, the optical film material needs to be coated on a PET film for testing. The specific test contents are as follows: Water resistance test of coating: Place the sample in a beaker filled with distilled water and immerse the sample in water. Refer to GB / T1733-93: Determination of water resistance of paint film. Take it out after 3 days, wipe off the water on the surface of the film, and observe and record the apparent state of the coating.

[0041] Transmittance test: Referring to the national standard "GBT2410-2008: Determination of transmittance and haze of transparent materials", the transmittance of the sample was tested using a WGT-S transmittance / haze tester. The transmittance is the ratio of the luminous flux passing through the sample to the luminous flux incident on the sample, expressed as a percentage, and the measured visible light wavelength is 550nm.

[0042] Pencil hardness test: According to the national standard "GB / T6739-2006: Determination of paint film hardness by pencil method for paints and varnishes", the sample is placed in a horizontal position, and the pencil hardness of the sample is measured by pushing pens with gradually increasing hardness on the sample. During the test, the pencil is fixed so that the pencil can be pressed down on the paint film surface at a 45° angle under a load of 750g, and pencils of different hardness slide with the film layer under a fixed pressure to observe whether there are indentations or scratches, until it is found that the pencil does not cut or scratch the surface of the sample, and the pencil hardness is obtained.

[0043] UV aging resistance test: According to the national standard GB / T16585-1996: Test method for artificial weathering of vulcanized rubber (fluorescent ultraviolet lamp), the test was carried out using a UV-B fluorescent ultraviolet lamp. The test conditions were a temperature of 57°C and an ultraviolet lamp intensity of 50W / m 2 The test time is 72h. After the test, a transmittance test is carried out to evaluate the change in transmittance.

[0044] The test results are shown in Table 1.

[0045] Table 1 Test results

[0046] Water resistance test From Example 6, it can be seen that too much addition of hydroxyethyl methacrylate will reduce the water resistance of the acrylate copolymer. From Example 1 and Comparative Example 1, it can be seen that directly adding nano zinc oxide will also lead to poor water resistance due to its poor compatibility with the acrylate copolymer.

[0047] From the transmittance test, it can be seen from Example 1 and Comparative Example 2 that the transmittance of the PET film coated with the optical film material is greatly improved. From Example 1 and Comparative Example 1, it can be seen that the silicon dioxide-doped zinc oxide composite material as a filler can improve the transmittance to a certain extent due to its good dispersibility in the acrylate copolymer.

[0048] Pencil hardness test From Example 1 and Comparative Example 1, it can be seen that the use of silicon dioxide-doped zinc oxide composite materials can improve the pencil hardness of the optical film material because it can be combined with the acrylate copolymer through a condensation reaction. Therefore, from Example 1 and Comparative Example 2, it can be seen that coating the optical film material on the PET film can significantly improve the pencil hardness of the PET film.

[0049] Transmittance after aging From Example 1 and Comparative Examples 1 and 2, it can be seen that the use of silicon dioxide-doped zinc oxide composite materials can effectively improve the aging resistance of optical film materials due to the spacing effect of silicon dioxide.

[0050] 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 preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should be included in the protection scope of the present invention.

Claims

1. An optical thin film material, characterized in that: The invention comprises the following components in parts by weight: 80-100 parts of an acrylate copolymer and 5-10 parts of a filler; the acrylate copolymer is prepared by polymerization of butyl methacrylate, hydroxyethyl methacrylate and gamma-methacryloxypropyltrimethoxysilane; and the filler is a silicon dioxide-doped zinc oxide composite material.

2. The optical thin film material according to claim 1, characterized in that: The filler is prepared from nano zinc oxide and tetraethyl orthosilicate.

3. A method for preparing an optical thin film material according to claim 1, characterized in that: include: Take the acrylic acid ester copolymer and add it into ethanol, adjust the pH value to 4-5, add deionized water, react at 40-50° C. for 20-30 minutes, add filler, and continue to react for 8-10 hours to obtain an optical film material.

4. The preparation method according to claim 3, characterized in that: The mass ratio of the acrylic ester copolymer to deionized water is 10:(1-2).

5. The preparation method according to claim 3, characterized in that: The preparation method of the acrylic ester copolymer comprises: Butyl methacrylate, hydroxyethyl methacrylate and γ-methacryloxypropyltrimethoxysilane were added to ethanol, and azobisisobutyronitrile was added. The mixture was fully mixed under an inert atmosphere, and the mixture was reacted at 60-70° C. for 4-8 hours to obtain an acrylate copolymer.

6. The preparation method according to claim 5, characterized in that: The mass ratio of the butyl methacrylate, hydroxyethyl methacrylate and γ-methacryloxypropyltrimethoxysilane is 100:(60-80):(1-3).

7. The preparation method according to claim 3, characterized in that: The preparation method of the filler comprises: Zinc oxide is added to ethanol, and then ethyl orthosilicate and deionized water are added, and the mixture is stirred at 30-40° C. for 20-30 hours. After the stirring is completed, the mixture is centrifugally dried to obtain a filler.

8. The preparation method according to claim 7, characterized in that: The molar ratio of the nano zinc oxide to tetraethyl orthosilicate is 1:(0.5-1).

9. The preparation method according to claim 1, characterized in that: The molar ratio of the tetraethyl orthosilicate to deionized water is 1:(4-6).

10. An application of the optical film material according to claim 1, characterized in that: The optical film material is coated on the surface of the PET film to prepare a composite optical film.

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