CN1311249C - Optical Films with UV Absorbing Capabilities - Google Patents

Abstract

The invention relates to an optical film, which comprises a substrate and is characterized in that at least one surface of the substrate is coated with a coating with ultraviolet absorption capacity. The optical film of the present invention has good weatherability and has an effect of absorbing ultraviolet rays.

Description

Optical Films with UV Absorbing Capabilities

technical field

The invention relates to an optical film, which comprises a substrate, and is characterized in that at least one surface of the substrate is coated with a coating with ultraviolet absorbing ability. The optical film of the invention can be used on glass or in flat displays, has good weather resistance, and has the effect of absorbing ultraviolet rays.

Background technique

If the human body is exposed to too much ultraviolet rays, it is easy to cause symptoms such as cataracts, skin cancer, burns and skin thickening. Therefore, ultraviolet rays have many adverse effects on the human body.

In addition, if the material is exposed to ultraviolet light for a long time, it will cause damage to the material, and it is prone to yellowing, embrittlement and deformation.

In order to reduce the damage of ultraviolet rays, people have been looking for strong and effective ultraviolet absorbing materials for many years, such as ultraviolet absorbers, but ultraviolet absorbers are organic substances, which have the disadvantages of short life and high toxicity. In order to improve the above shortcomings, they have been gradually developed and used recently. Nanoscale inorganic particles to replace UV absorbers.

The liquid crystal display (Liquid Crystal Display, LCD) imaging, first uses a back light source (back light source) to project light sources, these light sources will first pass through a polarizer and then pass through the liquid crystal molecules, at this time the arrangement of the liquid crystal molecules will change the penetration The angle of light from the liquid crystal, and then the light passes through the front color filter (color filter) and another polarizer. Therefore, as long as the voltage value to stimulate the liquid crystal molecules is changed, the intensity and color of the final light can be controlled, and then color combinations of different shades can be changed.

The light emitted by the backlight contains ultraviolet rays (UV), which can easily cause yellowing of the polymer resin in the optical film, resulting in weakened reflection effect and chromatic aberration of LCD.

The inventors of this case have found through extensive research that coating the surface of the optical film with a coating with ultraviolet absorption ability not only does not affect the adhesion of the optical film, but also absorbs most of the UV light in the backlight, and can make the optical film Provides durability and reduces its thickness. Using this kind of optical film can improve the brightness of liquid crystal display without changing related designs and molds, which can effectively solve the above-mentioned shortcomings.

Contents of the invention

The main purpose of the present invention is to provide an optical film comprising a substrate, characterized in that at least one surface of the substrate is coated with a coating having ultraviolet absorbing ability.

Detailed ways

The invention provides an optical film, which comprises a substrate, and is characterized in that at least one surface of the substrate is coated with a coating with ultraviolet absorbing ability.

The substrate used in the optical film of the present invention is not particularly limited, and may be transparent, translucent or opaque, which are well known to those skilled in the art. Generally, the substrate includes at least one layer of polymer resin. This polymer resin is not particularly limited, and it is for example but not limited to polyolefin resin (polyolefin resin), such as polyethylene (PE) or polypropylene (PP); Polyethylene formate (PET); polyacrylate resin, such as polymethyl methacrylate (PMMA); polycarbonate resin; polyurethane resin, or mixture. According to a preferred embodiment of the present invention, the optical film of the present invention uses a polyester resin substrate, preferably polyethylene terephthalate. The aforementioned substrates may optionally contain inorganic substances known to those skilled in the art, such as zinc oxide, silicon dioxide, titanium dioxide, aluminum oxide, calcium sulfate, barium sulfate, calcium carbonate or mixtures thereof. The substrate of the present invention may be single-layer or multi-layer, wherein one or more layers contain the inorganic particles. Specifically, the present invention may, for example, use a three-layer substrate in which the inorganic substance is contained in the middle layer.

The coating layer used in the optical film of the present invention has the ability to absorb ultraviolet light and contains inorganic fine particles and fluororesin.

The inorganic particles used in the optical film of the present invention are not particularly limited, and are used to absorb ultraviolet rays, such as but not limited to zinc oxide, silicon dioxide, titanium dioxide, aluminum oxide, calcium sulfate, barium sulfate, calcium carbonate or a mixture thereof . The particle size of the above-mentioned inorganic particles is generally 1-100 nanometers (nanometer), preferably 20-50 nanometers.

The content of inorganic particles in the resin composition of the present invention is 0.01-20% by weight, preferably 1-5% by weight, based on the total coating weight.

The fluororesin that can be used in the composition of the present invention is not particularly limited and is well known to those skilled in the art. It is preferably a copolymer formed by polymerizing fluoroolefin monomers and alkyl vinyl ether monomers , more preferably a chlorotrifluoroethylene tetrapolymer.

The fluoroolefin monomers that can be used to form fluororesins in the present invention are well known to those skilled in the art, such as but not limited to vinyl monofluoride, vinylidene fluoride, chlorotrifluoroethylene, tetrafluoroethylene, Hexafluoropropylene or a mixture thereof, preferably chlorotrifluoroethylene.

The alkyl vinyl ether monomer used to form the fluororesin of the present invention is not particularly limited, and it can be selected from linear alkyl vinyl ether monomers, side chain alkyl vinyl ether monomers, and cyclic alkyl vinyl ether monomers. The group consisting of vinyl ether monomers and hydroxyalkyl vinyl ether monomers and mixtures thereof. Preferably, the alkyl group in the alkyl vinyl ether has a carbon number of C ₂ -C ₁₁ .

The content of the fluororesin in the optical film of the present invention is 99.99 to 70% by weight, preferably 99 to 90% by weight, based on the total coating weight.

The coating of the optical film of the present invention can optionally add a curing agent (Curing Agent), which functions to produce a chemical bond between molecules and molecules with the bonding agent to form crosslinking (Crosslinking). The curing agent used in the present invention is well known to those skilled in the art, such as polyisocyanate (Polyisocyanate). The content of the hardener in the optical film of the present invention is 0 to 20% by weight, preferably 5 to 10% by weight, based on the total coating weight.

The optical film of the present invention may optionally contain additives known to those skilled in the art, such as fluorescent agents or UV absorbers or mixtures thereof.

The ultraviolet absorbers that can be used for the surface coating of the optical film of the present invention are known to those skilled in the art, such as benzotriazoles (benzotriazoles), benzotriazines, benzophenones (benzophenones) or salicylic acid derivatives (salicylic acid derivatives), etc.

The fluorescent agent that can be used for the surface coating of the optical film of the present invention is not particularly limited, and is known to those skilled in the art, and can be an organic substance, which includes but is not limited to benzoxazoles (benzoxazoles), benzene benzimidazoles or diphenylethylene bistriazines; or inorganic substances such as zinc sulfide.

The optical film of the invention can be used on the glass of general buildings or automobiles, and has good anti-UV effect. The optical film of the present invention can also be used in a liquid crystal display as a reflective film of a backlight source, can enhance brightness, has good weather resistance, and has the effect of absorbing ultraviolet rays, so as to enhance the effect of a liquid crystal display.

example

The following examples will further illustrate the present invention, but it is not intended to limit the scope of the present invention. Any corrections and changes achieved by those skilled in the art of the present invention without departing from the spirit of the present invention belong to the present invention. range.

Example 1

Add 126.6 grams of fluororesin [eterflon 410l, provided by Eternal] (about 60% solid content), add 45 grams each of methyl ethyl ketone/toluene, stir together (rotating speed 1000 rpm), and then add 3 grams of 35nm zinc oxide/barium sulfate in sequence, Hardener [desmodur 3390, provided by Bayer] 18.4 grams to form 250.0 grams of coating (solid content 40%), the coating is coated on the UX-150 (provided by Teijin) substrate, after drying, a coating film of 10 μm can be obtained, and left to stand After 7 days, do weather resistance test (using QUV weather resistance testing machine, Q-panel company). The test results are shown in Table 1 below.

Example 2

The procedure of Example 1 was repeated except that the substrate UX-150 (supplied by Teijin) was replaced by E60L (supplied by Toray). The test results are shown in Table 1 below.

Comparative example 1

The substrate UX-150 (provided by Teijin) not coated with a coating with ultraviolet absorbing ability was directly subjected to a weather resistance test (using a QUV weather resistance tester, Q-panel company). The test results are shown in Table 1 below.

Comparative example 2

The procedure of Comparative Example 1 was repeated except that the substrate UX-150 (supplied by Teijin) was replaced by E60L (supplied by Toray). The test results are shown in Table 1 below.

Table 1: QUV weather resistance accelerated test, with different exposure time, its yellowing index (Yellowing index, YI) value;

Variety

【The main wavelength of the test is 313m】 Exposure 20hrΔYI Exposure 40hrΔYI Exposure 110hrΔYI Exposure 150hrΔYI Exposure 200hrΔYI Exposure 200hrΔYI Example 1. 0.5 0.6 0.9 1.0 1.15 1.25 Example 2. 0.7 1.2 1.7 2.1 2.5 2.8 Comparative example 1. 0.73 2.06 4.96 5.95 8.76 11.26 Comparative example 2. 5.54 8.7 14.71 15.78 17.43 20.53

Comparing the results of Example 1 and Comparative Example 1 and Example 2 and Comparative Example 2, it can be seen that the coating with ultraviolet absorbing ability is coated on the surface of the substrate, which is better in anti-yellowing effect, so it has a good anti-UV effect .

Claims (11)

1. blooming, it comprises a base material, it is characterized by and have at least a substrate surface to be coated with coating with ultraviolet absorption ability, this coating comprises inorganic particles and fluoroplast, and wherein inorganic particles content is remembered with total coating weight, be 0.01～20 weight %, fluoroplast content with total coating weight note, is 99.99～70 weight %.

2. blooming according to claim 1, wherein this base material comprises at least one floor height molecule resin.

3. blooming according to claim 2, wherein this macromolecule resin is to be selected from the group that is made of vibrin, polyacrylate resin, polyalkenes resin, polycarbonate resin and polyurethane resin and composition thereof.

4. blooming according to claim 1, wherein this inorganic particles is to be selected from the group that is made of zinc paste, silicon dioxide, titania, aluminium oxide, calcium sulphate, barium sulphate and lime carbonate and composition thereof.

5. blooming according to claim 1, wherein the particle diameter of this inorganic particles is 1～100 nanometer.

6. blooming according to claim 1, wherein this fluoroplast comprises fluoroolefin monomers and C ₂～C ₁₁The multipolymer of alkyl vinyl ether monomer.

7. blooming according to claim 6, wherein this fluoroolefin monomers is to be selected from by a fluorothene, vinylidene fluoride, chlorotrifluoroethylene, tetrafluoroethene and hexafluoropropylene and group that mixing constituted thereof.

8. blooming according to claim 6, wherein this alkyl vinyl ether monomer is to be selected from the group that is made of straight chain shape alkyl vinyl ether monomer, side chain shape alkyl vinyl ether monomer, cyclic alkyl vinyl ether monomers and hydroxy alkyl vinyl ether monomers and composition thereof.

9. blooming according to claim 1, wherein this coating further comprises rigidizer.

10. blooming according to claim 1, wherein this coating further comprises fluorescer or ultraviolet light absorber or its potpourri.

11. blooming according to claim 1, it is to be used for the anti-UV reflectance coating of LCD as backlight.