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KR-20260065738-A - Polyvinyl alcohol film and method for manufacturing the same

KR20260065738AKR 20260065738 AKR20260065738 AKR 20260065738AKR-20260065738-A

Abstract

The present application provides a polyvinyl alcohol film and a method for manufacturing the same. The saturated absorption amount of the amorphous structure in the polyvinyl alcohol film is x, the absorption amount increased due to the destruction of the crystalline surface defect structure in the polyvinyl alcohol film is y, and x/(x+y) satisfies the condition that x/(x+y) is 0.82 to 0.93; the softening point of the polyvinyl alcohol film is 65°C to 75°C, and the degree of swelling of the polyvinyl alcohol film is 180% to 220%.

Inventors

  • 우 푸성
  • 탕 청홍
  • 시앙 쉬에이
  • 순 시엔우
  • 장 치엔레이
  • 왕 시아오시
  • 리 지아밍
  • 리우 타오
  • 왕 다오리앙

Assignees

  • 안후이 완웨이 업데이트 하이-테크 머터리얼 인더스트리 컴퍼니 리미티드
  • 안후이 완웨이 어드밴스드 펑셔널 멤브레인 머터리얼즈 리서치 인스티튜트 컴퍼니 리미티드

Dates

Publication Date
20260511
Application Date
20241125
Priority Date
20241028

Claims (12)

  1. In a polyvinyl alcohol film, The saturated absorption amount of the amorphous structure in the polyvinyl alcohol film is x, the absorption amount increased due to the destruction of the crystalline surface defect structure in the polyvinyl alcohol film is y, and x/(x+y) satisfies the condition that it is between 0.82 and 0.93; A polyvinyl alcohol film characterized by having a softening point of 65°C to 75°C and a swelling degree of 180% to 220%.
  2. In paragraph 1, A polyvinyl alcohol film characterized in that the above x/(x+y) is 0.84 to 0.89.
  3. In paragraph 1 or 2, A polyvinyl alcohol film characterized by having a crystallinity of 35% to 45% and a melting point of 210°C to 230°C.
  4. In paragraph 1 or 2, The test step for the saturated absorption amount of the amorphous structure among the polyvinyl alcohol films comprises: immersing at least one polyvinyl alcohol film in deionized water under a preset temperature and immersing it for a preset time (t1); after the amorphous structure among the polyvinyl alcohol films finishes absorbing, removing the polyvinyl alcohol film, scraping off water droplets from the surface of the polyvinyl alcohol film and measuring the weight, recording it as m x1 ; drying the polyvinyl alcohol film and measuring the weight, recording it as m x2 ; and the saturated absorption amount of the amorphous structure among the polyvinyl alcohol films is x = (m x1 - m x2 ) / m x2 * 100%; The test step for the sum of the saturated absorption amount of the amorphous structure of the polyvinyl alcohol film and the absorption amount increased due to the destruction of the crystalline surface defect structure of the polyvinyl alcohol film comprises the steps of: immersing at least one polyvinyl alcohol film in deionized water under a preset temperature, immersing for a preset time (t2), destroying the crystalline surface defect structure of the polyvinyl alcohol film, and after the destroyed crystalline surface defect structure has finished absorbing, removing the polyvinyl alcohol film, scraping off water droplets from the surface of the polyvinyl alcohol film and measuring the weight, recording it as m x3 , drying the polyvinyl alcohol film and measuring the weight, recording it as m x4 , and determining that the sum of the saturated absorption amount of the amorphous structure of the polyvinyl alcohol film and the absorption amount increased due to the destruction of the crystalline surface defect structure of the polyvinyl alcohol film is x+y = (m x3 - m x4 ) / m x4 * 100%. Polyvinyl alcohol film characterized by
  5. In paragraph 4, A polyvinyl alcohol film characterized by the above preset temperature being 30℃, the above t1 being 1 min, and the above t2 being 15 min.
  6. In a method for manufacturing a polyvinyl alcohol film according to any one of claims 1 to 5, A step of dissolving polyvinyl alcohol and additives in a solvent to obtain a casting film stock solution; A step of obtaining a pre-dried thin film after performing degassing, tape casting, and pre-drying on the above casting film raw material; and A method for manufacturing a polyvinyl alcohol film characterized by including the step of obtaining a polyvinyl alcohol film by performing heat treatment on the above-mentioned pre-dried thin film.
  7. In paragraph 6, In the step of obtaining a pre-dried thin film after performing degassing, tape casting, and pre-drying on the above-mentioned casting film raw material, the moisture content of the liquid film after tape casting is 15% to 35%; and/or In the step of obtaining a pre-dried thin film after performing degassing, tape casting, and pre-drying on the above-mentioned casting film raw material, the moisture content of the pre-dried thin film is 8% to 15%; and/or A method for manufacturing a polyvinyl alcohol film, characterized in that, in the step of obtaining a polyvinyl alcohol film by performing heat treatment on the above-mentioned pre-dried thin film, the water content of the polyvinyl alcohol film is 0.1% to 5%.
  8. In Paragraph 7, The water content of the liquid film after the above tape casting is 18% to 30%; and/or A method for manufacturing a polyvinyl alcohol film characterized in that the water content of the polyvinyl alcohol film is 0.5% to 3.5%.
  9. In any one of paragraphs 6 through 8, In the step of obtaining a polyvinyl alcohol film by performing heat treatment on the aforementioned pre-dried thin film, A method for manufacturing a polyvinyl alcohol film, characterized by including the step of sequentially performing heat treatment on the pre-dried thin film using an n-section temperature to obtain a polyvinyl alcohol film, wherein the temperature distribution of the n-section temperature shows a trend of rising first and then falling, and 2≤n≤20.
  10. In Paragraph 9, A polyvinyl alcohol film is obtained by sequentially performing heat treatment on the pre-dried thin film using the above n-section temperature, wherein, in the step where the temperature distribution of the above n-section temperature shows a trend of rising followed by falling, The time for performing heat treatment on the above-mentioned pre-dried thin film is t, and under conditions of 0%t to 20%t, heat treatment is performed on the above-mentioned pre-dried thin film using a first section temperature, wherein the first section temperature is 50℃ to 80℃; Under conditions of 20%t to 40%t, heat treatment is performed on the pre-dried thin film using a second section temperature, wherein the second section temperature is 55℃ to 95℃; Under conditions of 40%t to 60%t, heat treatment is performed on the pre-dried thin film using a third section temperature, wherein the third section temperature is 70℃ to 100℃; Under conditions of 60%t to 80%t, heat treatment is performed on the pre-dried thin film using a fourth section temperature, wherein the fourth section temperature is 100℃ to 130℃; A method for manufacturing a polyvinyl alcohol film, characterized by comprising the step of: performing a heat treatment on the pre-dried thin film using a fifth section temperature under conditions of 80%t to 100%t, wherein the fifth section temperature is 50℃ to 98℃; and thereby obtaining a polyvinyl alcohol film.
  11. In Paragraph 10, The step of sequentially performing heat treatment on the pre-dried thin film using the above n-section temperature includes the step of performing drying on the pre-dried thin film using a blower; A method for manufacturing a polyvinyl alcohol film, characterized in that the wind speed of the blower at the first section temperature is 5.9 m/s to 12.4 m/s, the wind speed of the blower at the second section temperature is 6.6 m/s to 13.1 m/s, the wind speed of the blower at the third section temperature is 13.2 m/s to 19.7 m/s, the wind speed of the blower at the fourth section temperature is 10.5 m/s to 17.0 m/s, and the wind speed of the blower at the fifth section temperature is 11.5 m/s to 18.0 m/s.
  12. In Paragraph 11, A method for manufacturing a polyvinyl alcohol film, characterized in that the wind speed of the blower at the first section temperature is 8.1 m/s to 10.3 m/s, the wind speed of the blower at the second section temperature is 8.8 m/s to 10.9 m/s, the wind speed of the blower at the third section temperature is 15.4 m/s to 17.5 m/s, the wind speed of the blower at the fourth section temperature is 12.7 m/s to 14.9 m/s, and the wind speed of the blower at the fifth section temperature is 13.7 m/s to 15.8 m/s.

Description

Polyvinyl alcohol film and method for manufacturing the same This application claims priority to Chinese patent application No. 202411507815.9 filed on October 28, 2024, and all contents of said Chinese patent application are incorporated by reference into this application. This application relates to the field of polyvinyl alcohol film technology, and in particular to polyvinyl alcohol film and a method for manufacturing the same. Polyvinyl alcohol (PVA) films are primarily used to manufacture polarizing films, and their final products are applied to display panels of various liquid crystal display devices, such as TVs, computer monitors, mobile phones, automotive navigation systems, and wearable electronic devices. The retention rate of optical performance of PVA polarizing films under high temperature and high humidity environments is a key indicator for evaluating the durability of PVA polarizing films. As display panels evolve to become thinner, more durable, and more transparent, higher demands are being placed on the durability performance of polyvinyl alcohol polarizing films and their upstream optical films, particularly in automotive applications. Below, a clear and complete description of the technical measures within the embodiments of this application will be provided in conjunction with the embodiments of this application. Of course, the described embodiments are merely a part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by a person skilled in the art without inventive labor fall within the scope of protection of this application. The “range” disclosed in this application is limited in the form of a lower limit and an upper limit, and a given range is limited by a selection of one lower limit and one upper limit, and the selected lower limit and upper limit define the boundaries of a particular range. A range limited in this way may include or not include end values and may be arbitrarily combined, that is, any lower limit may be combined with any upper limit to form a range. For example, it will be understood that if a range of 60-120 and 80-110 is listed for a specified parameter, the ranges of 60-110 and 80-120 are also predicted. Furthermore, if the listed minimum range values are 1 and 2, and the listed maximum range values are 3, 4 and 5, ranges such as 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5 can all be predicted. In this application, unless otherwise stated, the numeric range “a-b” represents an abbreviated notation for any combination of real numbers between a and b, wherein a and b are both real numbers. For example, the numeric range “0-5” represents any real number between “0-5” as arbitrarily listed in this application, and “0-5” is merely an abbreviated notation for such combination of numbers. Furthermore, when any parameter is expressed as an integer ≥2, it corresponds to disclosing that the parameter is, for example, an integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. Unless otherwise specified, all embodiments of the present application and selectable embodiments may be combined with one another to form a new technical solution. Unless otherwise specified, all technical features of the present application and selectable technical features may be combined with one another to form a new technical solution. Unless otherwise specified, all steps of the present application may proceed in order, may proceed randomly, and preferably proceed in order. For example, the method indicates that steps (a) and (b) may include steps (a) and (b) which are performed in order, and may include steps (b) and (a) which are performed in order. For example, the above-mentioned method may further include step (c), and step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), may include steps (a), (c), and (b), and may include steps (c), (a), and (b). Based on the fact that one of the causes affecting the durability of a polarizing film is the stability of the PVA-iodine complex in the polarizing film, the stability of the PVA-iodine complex is additionally influenced by the PVA film structure, and the specific surface area, stability, and crystal content of the crystals in the PVA film determine the content and stability of the fibrous PVA-polyiodine ion composite structure formed during the polarizing film processing process, and a polyvinyl alcohol film satisfying the following conditions of the present application has a crystal network with a high crystal specific surface area, a sufficient amount of crystal content, and appropriate crystal stability, which is advantageous for obtaining a polarizing film with excellent durability. The specific conditions are: x/(x+y) is 0.82 to 0.93, x is the saturated absorption amount of the amorphous structure in the polyvinyl alcohol film, y is the absorption amount increased due to the destruction of the crystalline surface de