High-durability polaroid and high-speed production method thereof

Abstract

The invention relates to the technical field of polaroids, and discloses a high-durability polaroid and a high-speed production method thereof, the high-speed production method refers to an extension fitting process, and comprises the steps of swelling, dyeing, cleaning, stretching, polarizer drying, protective layer fitting, gluing and the like. In the dyeing step, a dyeing solution in a dyeing solution tank is a dyeing solution containing dichroic substances and 0.5-1wt% of dyeing assistant, boride is contained in the washing and stretching steps, and the polarization photon drying temperature is 100 DEG C. The dichroic substance is composed of four dichroic azo dyes, and the produced high-durability polaroid meets the durability test requirement of 105 DEG C * 2000 h or even 115 DEG C * 1000 h. According to the method, the machine speed of extension and lamination of the polaroid can be remarkably improved, and the productivity of the polaroid is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of polarizers, and in particular to a highly durable polarizer that can be produced quickly and a production process thereof. Background Art

[0002] Polaroids are made of polaroid original plates and other functional films by coating pressure-sensitive adhesive. Polaroid original plates are formed by laminating stretched PVA, i.e. polarizers, and protective layers. The polarizers in the polarizer original plates play a decisive role in the weather resistance of polaroids. At present, the processing technology of polarizers is divided into two categories, dye series and iodine series, according to different dyeing media. The weather resistance of iodine series polarizers on the market is difficult to reach the weather resistance level of 105℃×1000h. The weather resistance of dye series polarizers can be improved to 100℃×500hr due to the use of dichroic azo dyes. However, with the increasing application of vehicle-mounted display screens, display screens in various fields are developing in the direction of large size and diversification. The requirements for the weather resistance of polaroids are getting higher and higher, the temperature requirements for dry temperature are increasing, and the requirements for the humidity of the thermometer at wet temperature are also increasing. The weather resistance test performance of polaroids requires 105℃ or even 115℃.

[0003] At present, in the polarizer manufacturing industry, the production of dye-based polarizers mostly uses the PVA film wet stretching process. The addition of chemicals in the bath has a great influence on the speed and quality of stretching. Too low or too high an amount of chemicals added will lead to reduced weather resistance, which is manifested as large optical fluctuations after weathering. The stretching speed also has a great influence on the optics and display effects of the polarizer, and the increase in stretching speed often leads to uneven dyeing. The above two factors limit the output speed of polarizer original plates, and the company's production capacity is therefore restricted. Summary of the invention

[0004] The purpose of the present invention is to provide a method for producing a polarizer that can be manufactured at high speed and has high durability. The high-durability polarizer meets the durability test requirements of 105°C×2000h or even 115°C×1000h, and at least provides a beneficial option or creates conditions for solving one or more technical problems existing in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solutions.

[0006] A high-speed production method for a highly durable polarizer, with a stretching and laminating speed of more than 9.5 m / min, comprises the following steps: 1) swelling, immersing a PVA film in pure water to swell the PVA film and clean the dirt on the surface; 2) dyeing, immersing the swollen and softened PVA film in a dyeing tank containing a dichroic substance to obtain an immersion dyeing treatment; 3) cleaning, cleaning the excess dye liquid carried on the surface of the PVA film after the dyeing treatment; 4) stretching, immersing the PVA film after the surface dye is cleaned in a stretching tank solution for stretching, so that the dye molecules are oriented and arranged inside the PVA film during stretching, and cross-linking is completed at the same time; 5) polarizer drying, placing the PVA film after the stretching treatment into a drying unit to obtain a polarizer film; 6) protective layer bonding, bonding the polarizer that has completed the drying treatment to two protective layers through an adhesive medium, and then passing through a baking unit to form a polarizer original plate; 7) gluing, the polarizer original plate is compounded with a functional film or a release film by coating a pressure-sensitive adhesive to obtain a polarizer with different characteristics.

[0007] Wherein, in step 2) the dyeing step, the dyeing tank contains 3-5wt% of dichroic substance and 0.5-1wt% of dyeing auxiliary, and the dichroic substance is composed of four azo dyes of different colors.

[0008] In step 3) the cleaning step, the cleaning tank liquid contains 0.1-0.5 wt% of boride.

[0009] In step 4) the stretching step, the stretching tank liquid contains 1-3 wt% of boride.

[0010] The boride is borax or boric acid.

[0011] More preferably, in step 3) the cleaning step, the temperature of the solution in the cleaning tank is 35-55° C., and the cleaning time is 30-120 seconds.

[0012] More preferably, in step 4) the stretching step, the temperature of the solution in the stretching tank is 45-65° C., and the stretching ratio is 5.5-7 times.

[0013] More preferably, in step 4) the stretching step, in the latter part of the stretching step, the tank solution contains 2.5-4 wt % of a color fixing agent, and the temperature of the tank solution is 28-45° C.

[0014] In step 5) the polarized light drying step, the drying temperature is 60-110° C., and the drying time is 120-300 seconds.

[0015] More preferably, in step 6) the protective layer laminating step, the two protective layers of the polarizer are triacetyl cellulose, and the adhesive medium is polyvinyl alcohol adhesive or UV adhesive.

[0016] More preferably, in step 6) the protective layer laminating step, the temperature of the baking unit after the polarizer and the protective layer are laminarized is 70-120° C., and the baking time is 150-600 seconds.

[0017] More preferably, in step 7) the gluing step, the components of the pressure-sensitive adhesive are: 20-60% pressure-sensitive adhesive acrylic copolymer, 0.1-30% tackifier, 10-79% solvent, 0.01-10% bridging agent, and 0.01-5% silane coupling agent, calculated by weight percentage.

[0018] More preferably, in step 7) the glue coating step, the functional film is a phase difference compensation film.

[0019] The present invention also provides a high-durability polarizer produced by the high-speed production method of the high-durability polarizer as described above.

[0020] The present invention adopts the above technical solution to have at least the following beneficial effects.

[0021] The present invention adopts a specific concentration of expanded material in the washing and stretching sections of polarizer preparation, so that the PVA film is greatly improved in terms of removing excess dyes on the surface and the stability and efficiency of the directional arrangement of dye molecules in the stretching process, so that the polarizer can achieve high durability and high polarization while increasing the machine speed. This method can increase the process speed of the polarizer original plate to 12m / min, achieving a leap in the production capacity of the polarizer. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Shown is a schematic structural diagram of a highly weather-resistant polarizer in Example 1 of the present invention.

[0023] Figure 2 Shown is a schematic structural diagram of a highly weather-resistant polarizer in Example 2 of the present invention. DETAILED DESCRIPTION

[0024] In order to facilitate those skilled in the art to better understand the essence of the present invention, the specific implementation methods of the present invention are described in detail below. Example 1.

[0025] like Figure 1 As shown, a highly durable polarizer has a composite structure from top to bottom: a protective film 1, a first polarizer protective layer 2, a polarizer 4, a second polarizer protective layer 5, a pressure-sensitive adhesive layer 6 and a peeling film layer 7, and adhesives 3 are provided on the upper and lower sides of the polarizer 4, respectively.

[0026] The manufacturing steps of the above-mentioned high-durability polarizer are as follows.

[0027] 1) Swelling: Soak the PVA film in pure water to swell the PVA film and clean the dirt on the surface.

[0028] 2) Dyeing: The swollen and softened PVA film is immersed in a dyeing tank containing a dichroic substance, the concentration of the dichroic azo dye in the dyeing tank is controlled at 5wt%, and the concentration of the auxiliary dye is controlled at 1wt%, to obtain an immersion dyeing treatment.

[0029] In this embodiment, the dichroic azo dye is a mixture of four dyes, among which the concentration of dye 1 is 10wt%, the concentration of dye 2 is 30wt%, the concentration of dye 3 is 20wt%, and the concentration of dye 4 is 40wt%; the total dye is 100%. The structural formulas of the four dichroic azo dyes can be found in the Chinese invention patent application with publication number CN115728857A previously applied by the applicant.

[0030] 3) Washing: The excess dye on the surface of the PVA film after dyeing is washed. The washing tank liquid contains 0.3wt% swelling acid, the tank solution temperature is 40°C, and the washing time is 35s.

[0031] 4) Stretching: The PVA film with the surface dye cleaned is immersed in a stretching tank solution for stretching, so that the dye molecules are oriented inside the PVA film during stretching and cross-linking is completed at the same time; the stretching tank liquid contains 3wt% boride, the tank solution temperature is 65°C, and the stretching ratio is 7 times; in the latter stage of the stretching step, the tank solution contains 4wt% color fixing agent, and the tank solution temperature is 28°C, so that the dye molecules are more stably arranged inside the polarizer.

[0032] 5) Polarized light drying: placing the PVA film that has completed the stretching process into a drying unit to obtain a polarized light film; the polarized light drying temperature is 60° C., and the drying time is 280 seconds.

[0033] 6) Protective layer bonding: the polarizer that has finished drying is bonded to the two protective layers through an adhesive medium, and then passed through a baking unit to form a polarizer original plate; the first and second polarizer protective layers are triacetate cellulose, the adhesive medium is polyvinyl alcohol adhesive, the baking temperature is 70°C, and the baking time is 400 seconds.

[0034] 7) Gluing: Apply pressure-sensitive adhesive on the surface of the polarizer original plate so as to bond it with the peeling film layer.

[0035] After actual production testing, the high-durability polarizer preparation process provided in this embodiment meets the production requirement of a stretching compounding speed of 9.5-10 m / min.

[0036] In this embodiment, the components of the pressure-sensitive adhesive are: 60 wt % of pressure-sensitive adhesive acrylic copolymer, 1 wt % of tackifier, 38 wt % of solvent, 0.5 wt % of bridging agent, and 0.5 wt % of silane coupling agent. Example 2.

[0037] Reference Figure 2 As shown, a highly durable polarizer, the structure of which is basically the same as that of Example 1, except that it is compounded with a phase difference compensation film 8.

[0038] The manufacturing steps of the high-durability polarizer in this embodiment are as follows.

[0039] 1) Swelling: Soak the PVA film in pure water to swell the PVA film and clean the dirt on the surface.

[0040] 2) Dyeing, soaking the swollen and softened PVA film in a dyeing tank containing a dichroic substance, the concentration of the dichroic azo dye in the dyeing tank is controlled at 3wt%, and the concentration of the auxiliary dye is controlled at 0.5wt%, to obtain an immersion dyeing treatment. In this embodiment, the dichroic azo dye is a mixture of four dyes, among which the concentration of dye 1 is 5wt%, the concentration of dye 2 is 30wt%, the concentration of dye 3 is 30wt%, and the concentration of dye 4 is 35wt%; the total dye is 100%. The structural formulas of the four dichroic azo dyes can be found in the Chinese invention patent application with publication number CN115728857A previously applied by the applicant.

[0041] 3) Washing: The excess dye on the surface of the PVA film after dyeing is washed. The washing tank liquid contains 0.1wt% swelling acid, the tank solution temperature is 40°C, and the washing time is 60s.

[0042] 4) Stretching: The PVA film with the surface dye cleaned is immersed in a stretching tank solution for stretching, so that the dye molecules are oriented inside the PVA film during stretching and cross-linking is completed at the same time. The stretching tank liquid contains 1.5wt% of boride, the tank solution temperature is 45°C, and the stretching ratio is 7 times; in the latter stage of the stretching step, the tank solution contains 2.5wt% of a color fixing agent, and the tank solution temperature is 35°C, so that the dye molecules are more stably arranged inside the polarizer.

[0043] 5) Polarized light drying: placing the PVA film that has completed the stretching process into a drying unit to obtain a polarized light film; the polarized light drying temperature is 100° C., and the drying time is 150 seconds.

[0044] 6) Protective layer bonding: the polarizer that has finished drying is bonded to the two protective layers through an adhesive medium, and then passed through a baking unit to form a polarizer original plate; the first and second polarizer protective layers are triacetate cellulose, the adhesive medium is polyvinyl alcohol adhesive, the baking temperature is 120°C, and the baking time is 150 seconds.

[0045] 7) Gluing: Apply acrylic resin pressure-sensitive adhesive on the surface of the polarizer original plate and composite the phase difference compensation film; continue to apply pressure-sensitive adhesive under the phase difference compensation film so as to bond it with the peeling film layer.

[0046] After actual production testing, the high-durability polarizer preparation process provided in this embodiment meets the production requirement of a stretching compounding speed of 11-12 m / min.

[0047] In this embodiment, the components of the pressure-sensitive adhesive are: 60 wt % of pressure-sensitive adhesive acrylic copolymer, 1 wt % of tackifier, 38 wt % of solvent, 0.5 wt % of bridging agent, and 0.5 wt % of silane coupling agent.

[0048] Comparative Example 1

[0049] A polarizer is prepared by the following steps.

[0050] 1) Swelling: Soak the PVA film in pure water to swell the PVA film and clean the dirt on the surface.

[0051] 2) Dyeing: The swollen and softened PVA film is immersed in a dyeing tank containing a dichroic substance. In the dyeing tank, the concentration of the dichroic azo dye is controlled at 2wt%, and the concentration of the auxiliary dye is controlled at 0.3wt%, so as to obtain an immersion dyeing treatment.

[0052] In this comparative example, the dichroic azo dye is a mixture of four dyes, among which the concentration of dye 1 is 5wt%, the concentration of dye 2 is 30wt%, the concentration of dye 3 is 30wt%, and the concentration of dye 4 is 35wt%; the total dye is 100%. The structural formulas of the four dichroic azo dyes can be found in the Chinese invention patent application with publication number CN115728857A previously applied by the applicant.

[0053] 3) Washing: The excess dye on the surface of the PVA film after dyeing is washed. The washing tank liquid contains 2-4wt% swelling acid, the tank solution temperature is 40°C, and the washing time is 60s.

[0054] 4) Stretching: The PVA film with the surface dye cleaned is immersed in a stretching tank solution for stretching, so that the dye molecules are oriented inside the PVA film during stretching and cross-linking is completed at the same time. The stretching tank liquid contains 4-7wt% boride, the tank solution temperature is 45-65°C, and the stretching ratio is 6 times; in the latter stage of the stretching step, the tank solution contains 2.5-4wt% of a color fixing agent, and the tank solution temperature is 28-35°C, so that the dye molecules are more stably arranged inside the polarizer.

[0055] 5) Polarized light drying: placing the stretched PVA film into a drying unit to obtain a polarized light film; the polarized light drying temperature is 60° C., and the drying time is 260 seconds.

[0056] 6) Protective layer bonding: the polarizer that has finished drying is bonded to the two protective layers through an adhesive medium, and then passed through a baking unit to form a polarizer original plate; the first and second polarizer protective layers are triacetate cellulose, the adhesive medium is polyvinyl alcohol adhesive, the baking temperature is 70-80°C, and the baking drying time is 600 seconds.

[0057] 7) Glue coating: apply acrylic resin pressure-sensitive adhesive on the surface of the polarizer original plate and composite phase difference compensation film; continue to apply pressure-sensitive adhesive under the phase difference compensation film to bond with the peeling film layer. The components of the pressure-sensitive adhesive are: 60wt% of pressure-sensitive adhesive acrylic copolymer, 1wt% of tackifier, 38wt% of solvent, 0.5wt% of bridging agent, and 0.5wt% of silane coupling agent.

[0058] After actual production testing, the polarizer preparation process provided in this comparative example can only meet the production requirement of a stretching compounding speed of 6 to 6.5 m / min.

[0059] Comparative example 2.

[0060] The high-durability polarizer prepared in this comparative example is basically the same as that in Example 1, except that the dichroic azo dyes used in the dyeing step are 20wt% of Dye 1, 40wt% of Dye 2 and 40wt% of Dye 4, and the dye concentration is 1% to 2wt%; the washing tank liquid contains 0wt% swelling acid; the stretching tank liquid contains 4~7wt% boride, and the stretching composite speed is 6~6.5m / min.

[0061] Comparative example 3.

[0062] The high-durability polarizer prepared in this comparative example is basically the same as that in Example 1, except that the dichroic azo dyes used in the dyeing step are 20wt% of Dye 1, 40wt% of Dye 2 and 40wt% of Dye 4, with a concentration of 1% to 2wt%; the washing tank liquid contains 2 to 4wt% of swelling acid; the stretching tank liquid contains 4 to 7wt% of boride, and the stretching composite speed is 6 to 6.5 m / min.

[0063] In order to better reflect the advancement of the present invention, the polarizers prepared in Examples 1-2 and Comparative Examples 1-3 are subjected to performance comparison tests. The results are shown in Tables 1 and 2.

[0064] Table 1. Comparison of optical performance .

[0065] It can be seen from Table 1 that the polarizers produced in the embodiments of the present invention have a higher polarization degree, and the high polarization degree is still maintained after the production speed is increased. Compared with Comparative Example 1, Comparative Examples 2 and 3 have much lower polarization degrees at the same production speed.

[0066] Table 2. Weather resistance comparison table .

[0067] From the weathering results in Table 2, it can be seen that the embodiment uses a specific amount of expanded material added in the washing tank and the stretching tank, so that even after the production speed of the polarizer original plate is increased, it still meets the 105℃×2000h weathering test requirements and no obvious yellowing occurs. Compared with comparative examples 2 and 3, the polarizer of the present invention has excellent weathering performance; at the same time, the high-durability polarizer prepared by the present invention can still achieve good weathering performance under high-speed production conditions.

[0068] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0069] The above embodiments only express several implementation methods of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. The parts not described in the specific embodiments are all prior art or common knowledge.

[0070] It should be noted that, in the description of the present invention, the content of the present invention can be more easily understood by referring to the detailed description of the preferred implementation method of the present invention and the embodiments included. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those of ordinary skill in the art to which the present invention belongs. When there is a conflict, the definitions in this specification shall prevail.

[0071] In the present invention, the term "prepared from..." is used synonymously with "comprising". The terms "comprising", "including", "having", "containing" or any other variation thereof, as used in the present invention, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus comprising the listed elements is not necessarily limited to only those elements, but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0072] In the present invention, when an amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range limited by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including a range of "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5" etc. When a numerical range is described in the present invention, unless otherwise stated, the range is intended to include its end values ​​and all integers and fractions within the range.

[0073] In addition, the indefinite articles "a" and "an" before the elements or components of the present invention have no restrictions on the quantity requirements (i.e. the number of occurrences) of the elements or components. Therefore, "a" or "an" should be interpreted as including one or at least one, and the elements or components in the singular form also include the plural form, unless the number is obviously intended to be in the singular form.

Claims

1. A high-speed production method for a highly durable polarizer, characterized in that: The stretching compounding speed is above 9.5 m / min, and includes the following steps: 1) Swelling: soak the PVA film in pure water to swell the PVA film and clean the surface dirt; 2) Dyeing, immersing the swollen and softened PVA film in a dyeing tank containing a dichroic substance to obtain an immersion dyeing treatment; 3) Wash and clean the excess dye on the surface of the PVA film that has been dyed; 4) Stretching: The PVA film with the surface dye cleaned is immersed in a stretching tank solution for stretching, so that the dye molecules are oriented inside the PVA film during stretching and cross-linking is completed at the same time; 5) Polarized light drying: placing the PVA film that has completed the stretching process into a drying unit for drying to obtain a polarized light film; 6) Protective layer bonding: the polarizer that has finished drying is bonded to the two protective layers through an adhesive medium, and then passes through a baking unit to form a polarizer original plate; 7) Gluing: the polarizer original plate is composited with a functional film or a release film by coating a pressure-sensitive adhesive to obtain a polarizer with different properties; In step 2) of dyeing, the dyeing tank contains 3-5 wt% of a dichroic substance and 0.5-1 wt% of a dyeing aid, and the dichroic substance is composed of four azo dyes of different colors; In step 3) of the cleaning step, the cleaning tank liquid contains 0.1 to 0.5 wt% of boride; In step 4) the stretching step, the stretching tank liquid contains 1 to 3 wt% of boride; The boride is borax or boric acid.

2. The high-speed production method of a highly durable polarizer according to claim 1, characterized in that: In step 3) the cleaning step, the temperature of the solution in the cleaning tank is 35-55°C, and the cleaning time is 30-120s.

3. The high-speed production method of a highly durable polarizer according to claim 1, characterized in that: In step 4) the stretching step, the solution temperature of the stretching tank body is 45 to 65° C., and the stretching ratio is 5.5 to 7 times.

4. The high-speed production method of a highly durable polarizer according to claim 1, characterized in that: In step 4) the stretching step, in the latter part of the stretching step, the tank solution contains 2.5-4wt% of a color fixing agent, and the temperature of the tank solution is 28-45°C.

5. The high-speed production method of a highly durable polarizer according to claim 1, characterized in that: In step 5) the polarized light drying step, the drying temperature is 60-110° C., and the drying time is 120-300 seconds.

6. The high-speed production method of a highly durable polarizer according to claim 1, characterized in that: In step 6) the protective layer lamination step, the two protective layers of the polarizer are triacetyl cellulose, and the adhesive medium is polyvinyl alcohol adhesive or UV adhesive.

7. The high-speed production method of a highly durable polarizer according to claim 1, characterized in that: In step 6) the protective layer laminating step, the temperature of the baking unit after the polarizer and the protective layer are laminar is 70-120° C., and the baking time is 150-600 seconds.

8. The high-speed production method of a highly durable polarizer according to claim 1, characterized in that: In step 7) of coating, the components of the pressure-sensitive adhesive are: 20-60% of pressure-sensitive adhesive acrylic copolymer, 0.1-30% of tackifier, 10-79% of solvent, 0.01-10% of bridging agent, and 0.01-5% of silane coupling agent, calculated by weight percentage.

9. The high-speed production method of a highly durable polarizer according to claim 1, characterized in that: In step 7) the glue coating step, the functional film is a phase difference compensation film.

10. A highly durable polarizer produced by the high-speed production method for a highly durable polarizer as described in any one of claims 1 to 9.

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