PolyPA dye-based polarizer and preparation method thereof

Abstract

The invention discloses a poly PA dye system polaroid which comprises an upper PA layer, a PVA layer and a lower PA layer which are sequentially stacked from top to bottom, the upper PA layer and the PVA layer are bonded through a UV adhesive, and the PVA layer and the lower PA layer are bonded through a UV adhesive. The UV adhesive is a free radical type acrylic adhesive and / or a cationic epoxy adhesive; the adhesive force between the upper PA layer and the PVA layer and the adhesive force between the PVA layer and the lower PA layer are larger than 1000 gf / 25 mm. The poly PA dye system polaroid is resistant to bending, resistant to high temperature and water soaking and free of rainbow lines.

Description

Technical Field

[0001] The present invention relates to the technical field of polarizers, and in particular to a poly-PA dye-based polarizer and a preparation method thereof. Background Art

[0002] Polarizer is a material that can selectively absorb natural light. It can effectively absorb light perpendicular to the polarization axis, allowing light in the direction of the polarization axis to pass through, and ultimately turning natural light into linearly polarized light. Currently, polarizers can be divided into two types according to dyeing materials: iodine-based polarizers and dye-based polarizers.

[0003] Iodine-based polarizers have high transmittance and high polarization properties, but because the iodine in iodine-based polarizers is easy to sublimate and volatilize, its application field is limited.

[0004] Dye-based polarizers mainly use high dichroic dyes as light absorbers to effectively absorb light in a certain direction. High dichroic dyes have the ability to withstand high temperature and humidity, so the dye-based polarizers produced also have the ability to withstand high temperature and humidity.

[0005] Polarized glasses have become a must-have product for outdoor travel because of their polarization and sunlight absorption characteristics. The commonly used processing technologies for polarized glasses are stamping, sandwich and casting. The stamping method is still the main method used in the market. However, the product structures currently available on the market are all polarizers with a PC-TAC-PVA-TAC structure. The aforementioned PC is polycarbonate, TAC is triacetate cellulose film (Triacetate Cellulose), and PVA is polyvinyl alcohol. This type of polarizer has poor water resistance and high temperature resistance. At the same time, because the rigidity of PC material is relatively large, PC that is pressed and bent in the lens factory is prone to cracks or stress shrinkage, resulting in changes in the optics of the finished lens and affecting product quality. Summary of the invention

[0006] The technical problem to be solved by the present invention is to overcome the poor water resistance and high temperature resistance of the existing polarized glasses polarizers, and the defects that PC pressed and bent in the eyeglass lens factory is prone to cracks or stress shrinkage. A poly-PA dye-based polarizer and a preparation method thereof are proposed. The prepared poly-PA dye-based polarizer is resistant to bending, high temperature immersion in water and does not produce rainbow patterns.

[0007] In order to solve the above technical problems, the present invention proposes the following technical solutions: a poly-PA dye-based polarizer, comprising an upper PA layer, a PVA layer and a lower PA layer stacked in sequence from top to bottom, wherein the upper PA layer and the PVA layer and the PVA layer and the lower PA layer are bonded by UV adhesive;

[0008] The UV adhesive is a free radical acrylic adhesive and / or a cationic epoxy adhesive;

[0009] The adhesion between the upper PA layer and the PVA layer and between the PVA layer and the lower PA layer is greater than 1000 gf / 25 mm.

[0010] The above technical solution is further limited in that the thickness of the upper PA layer is 60-120 um, the thickness of the PVA layer is 20-35 um, and the thickness of the lower PA layer is 60-120 um.

[0011] The above technical solution is further limited in that the thickness of the upper PA layer is 80-100 um, the thickness of the PVA layer is 25-30 um, and the thickness of the lower PA layer is 80-100 um.

[0012] A further limitation of the above technical solution is that a protective film is compounded on the upper PA layer, and the protective film is a PE material protective film or a PET material protective film.

[0013] A further limitation of the above technical solution is that the phase difference value Re of the lower PA layer is ≤20 um.

[0014] In order to solve the above technical problems, the present invention proposes the following technical solutions: A method for preparing a poly-PA dye-based polarizer, comprising the following steps:

[0015] Step 1: PVA is unrolled and sequentially washed, swollen, dyed, stretched, color-corrected and dried to obtain PVA element;

[0016] Step 2: Use UV adhesive to bond PA above and below the PVA element to form an upper PA layer and a lower PA layer.

[0017] In order to solve the above technical problems, the present invention proposes the following technical solutions: A method for preparing a poly-PA dye-based polarizer, comprising the following steps:

[0018] Step 1: PVA is unrolled and sequentially washed, swollen, dyed, stretched, color-corrected and dried to obtain PVA element;

[0019] Step 2: Use UV adhesive to bond PA above and below the PVA element to form an upper PA layer and a lower PA layer;

[0020] Step 3: Compound a protective film on the upper PA layer.

[0021] The above technical solution is further limited in that the solvent for washing and swelling is deionized water at a temperature of 25-32°C; the solvent used for dyeing is high dichroic red, yellow and blue dyes, the ratio of the dyes is yellow: red: blue is 1:2:2.6, the solubility of the dye solution is 0.2%-1%, and the dyeing temperature is 30°C-40°C; the stretching solution is a boric acid solution, wherein the solubility of the boric acid is 1%-5%, and the stretching temperature is 40-55°C; the solution of the color-replenishing tank is a boric acid solution, wherein the solubility of the boric acid is 1%-5%, and the temperature of the color-replenishing tank solution is 30-35°C; the drying temperature is 45-80°C.

[0022] A further limitation of the above technical solution is that the UV lamp used in the bonding process of step 2 includes a mercury lamp, a halogen lamp or an organic lamp.

[0023] A further limitation of the above technical solution is that the protective film is a PET protective film or a PE protective film.

[0024] Compared with the prior art, the present invention has the following beneficial effects: the polyPA dye-based polarizer of the present invention is resistant to bending, high temperature and water immersion, and does not have rainbow lines. Because the UV glue uses a free radical acrylic adhesive and / or a cationic epoxy adhesive, this type of UV glue is a solvent-based UV glue that is insoluble in water, so it has obvious high temperature and water immersion resistance. And a PA material with a low phase difference value is selected, so no rainbow lines appear. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the structure of the poly-PA dye polarizer in an embodiment of the present invention.

[0026] Figure 2 It is a schematic structural diagram of a poly-PA dye-based polarizer in another embodiment of the present invention. DETAILED DESCRIPTION

[0027] See also Figure 1 A poly-PA dye-based polarizer comprises an upper PA layer 1, a PVA layer 2 and a lower PA layer 3 which are stacked in sequence from top to bottom.

[0028] The thickness of the upper PA layer 1 is 60-120 um, preferably 80-100 um.

[0029] The thickness of the PVA layer 2 is 20-35 um, preferably 25-30 um.

[0030] The thickness of the lower PA layer 3 is 60-120 um, preferably 80-100 um.

[0031] The phase difference value Re of the lower PA layer 3 is ≤ 20um. The larger the phase difference value is, the more likely rainbow patterns will appear in the appearance inspection.

[0032] UV adhesive is used to bond the upper PA layer 1 and the PVA layer 2, and the PVA layer 2 and the lower PA layer 3. The UV adhesive can be a free radical acrylic adhesive, a cationic epoxy adhesive, or a mixed adhesive of the above two. The UV adhesive in this embodiment can be ADEKA glue or LG glue.

[0033] The adhesion between the upper PA layer 1 and the PVA layer 2 and between the PVA layer 2 and the lower PA layer 3 is greater than 1000 gf / 25 mm.

[0034] See also Figure 2 In another embodiment, a protective film 4 may be compounded on the upper PA layer 1 according to product requirements. The protective film 4 may be a PE material protective film or a PET material protective film.

[0035] The preparation method of the poly-PA dye polarizer comprises the following steps:

[0036] Step 1: Use 60um thick PVA unwinding, and sequentially undergo water washing, swelling, dyeing, stretching, coloring and drying to obtain PVA element (PVA layer 2). The solvent for water washing and swelling is deionized water, and the temperature is 25-32°C. The solvent used in the dyeing tank is high dichroic red, yellow and blue dyes, and the ratio of the dyes is yellow: red: blue is 1:2:2.6. The solubility of the dye solution is between 0.2%-1%, and the dyeing temperature is 30°C-40°C. The solution of the stretching tank is a boric acid solution, wherein the solubility of boric acid is 1%-5%, and the stretching temperature is 40-55°C. The solution of the coloring tank is a boric acid solution, wherein the solubility of boric acid is 1%-5%, and the temperature of the coloring tank solution is 30-35°C. The drying temperature is 45-80°C, preferably 60-75°C.

[0037] Step 2: Use the above-mentioned UV adhesive to bond PA above and below the PVA element (PVA layer 2) to form an upper PA layer 1 and a lower PA layer 3, respectively. The UV lamp used can be a mercury lamp, a halogen lamp or an organic lamp.

[0038] Step 3: Compound a PET protective film or a PE protective film (protective film 4) on the upper PA layer 1.

[0039] Step 4: Test the adhesiveness and appearance of the polarizing film. The appearance test method is: place the sample on a backlight with a polarizing film for testing, and the absorption axis of the sample is perpendicular to the absorption axis of the backlight's own polarizing film.

[0040] Preparation Example 1

[0041] PVA (M6000) from Mitsubishi Chemical was selected and sequentially subjected to the steps of washing, swelling, dyeing, stretching, coloring and drying to obtain PVA element (PVA layer 2). The temperatures of the solutions in each tank were 27°C, 27°C, 31°C, 45°C, 30°C and 65°C respectively. The solubility of the dye solution in the dyeing tank was 0.5%, the solubility of the boric acid in the stretching tank was 2.0%, and the solubility of the boric acid in the coloring tank was 1.5%.

[0042] UV adhesive is used to bond PA above and below the PVA element (PVA layer 2) to form an upper PA layer 1 and a lower PA layer 3, wherein the UV lamp used is halogen light, and the UV adhesive is ADEKA glue or LG glue. The Re value of the lower PA layer 3 is 5um.

[0043] A PET protective film or a PE protective film (protective film 4 ) is laminated on the upper PA layer 1 .

[0044] Preparation Example 2

[0045] The implementation steps are the same as those of Preparation Example 1, except that the Re value of the material of the lower PA layer 3 is 20 um.

[0046] Comparative Example 1

[0047] The implementation steps are the same as those of Preparation Example 1, except that the adhesive is PVA water glue for bonding.

[0048] Comparative Example 2

[0049] The implementation steps are the same as those of Preparation Example 1, except that the Re value of the lower PA material is 50 um.

[0050] Comparative Example 3

[0051] The implementation steps are the same as those of Preparation Example 1, with the only difference being that the upper and lower functional layers (corresponding to the upper PA layer 1 and the PVA layer 2) are both replaced with PC.

[0052] The test results of the above embodiments and comparative examples are shown in the following table:

[0053]

[0054] The present invention has the following beneficial effects: the poly-PA dye-based polarizer of the present invention is resistant to bending, high temperature and water immersion and has no rainbow pattern.

Claims

1. A poly-PA dye-based polarizer, characterized in that: It includes an upper PA layer, a PVA layer and a lower PA layer stacked in sequence from top to bottom, and the upper PA layer and the PVA layer as well as the PVA layer and the lower PA layer are bonded by UV adhesive; The UV adhesive is a free radical acrylic adhesive and / or a cationic epoxy adhesive; The adhesion between the upper PA layer and the PVA layer and between the PVA layer and the lower PA layer is greater than 1000 gf / 25 mm.

2. The poly-PA dye-based polarizer according to claim 1, characterized in that: The thickness of the upper PA layer is 60-120um, the thickness of the PVA layer is 20-35um, and the thickness of the lower PA layer is 60-120um.

3. The poly-PA dye-based polarizer according to claim 1, characterized in that: The thickness of the upper PA layer is 80-100um, the thickness of the PVA layer is 25-30um, and the thickness of the lower PA layer is 80-100um.

4. The poly-PA dye-based polarizer according to claim 1, characterized in that: A protective film is compounded on the upper PA layer, and the protective film is a PE material protective film or a PET material protective film.

5. The poly-PA dye-based polarizer according to claim 1, characterized in that: The phase difference value Re of the lower PA layer is ≤20um.

6. A method for preparing a poly-PA dye-based polarizer as claimed in claim 1, characterized in that: The following steps are involved: Step 1: PVA is unrolled and sequentially washed, swollen, dyed, stretched, color-corrected and dried to obtain PVA element; Step 2: Use UV adhesive to bond PA above and below the PVA element to form an upper PA layer and a lower PA layer.

7. A method for preparing a poly-PA dye-based polarizer as claimed in claim 1, characterized in that: The following steps are involved: Step 1: PVA is unrolled and sequentially washed, swollen, dyed, stretched, color-corrected and dried to obtain PVA element; Step 2: Use UV adhesive to bond PA above and below the PVA element to form an upper PA layer and a lower PA layer; Step 3: Compound a protective film on the upper PA layer.

8. The method for preparing a poly-PA dye-based polarizer according to claim 6 or 7, characterized in that: The solvent for washing and swelling is deionized water with a temperature of 25-32°C; the solvent for dyeing is high dichroic red, yellow and blue dyes with a dye ratio of yellow: red: blue of 1:2:2.6, a solubility of the dye solution of 0.2%-1%, and a dyeing temperature of 30°C-40°C; the stretching solution is a boric acid solution with a boric acid solubility of 1%-5%, and a stretching temperature of 40-55°C; the solution in the color-replenishing tank is a boric acid solution with a boric acid solubility of 1%-5%, and a temperature of the color-replenishing tank solution of 30-35°C; and the drying temperature is 45-80°C.

9. The method for preparing a poly-PA dye-based polarizer according to claim 6 or 7, characterized in that: The UV lamp used in the bonding process of step 2 includes a mercury lamp, a halogen lamp, or an organic lamp.

10. The method for preparing a poly-PA dye-based polarizer according to claim 7, characterized in that: The protective film is a PET protective film or a PE protective film.

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