JP4518964B2 - Method and apparatus for swelling polyvinyl alcohol film and method and apparatus for producing polarizing film - Google Patents

Description

This invention is based on swelling water applied to a polyvinyl alcohol film (hereinafter referred to as “PVA film”) as a base material in the production of a polarizing film (polarizer) which is a main member of a liquid crystal display (LCD). The present invention relates to a swelling method and apparatus, and a method and apparatus for producing a polarizing film by subjecting a PVA film swollen by the swelling method and apparatus to a treatment such as dyeing and stretching .

  As is well known, this type of PVA film is swelled by conveying and guiding the swollen water through a plurality of guide rollers in which the PVA film is placed in the swollen water (for example, see Patent Document 1).

However, since this well-known swelling method of PVA film is swelling by natural penetration of the swelling water into the PVA film, as the PVA film becomes wider as in recent years, unevenness in the penetration of the swelling water occurs. It is difficult to uniformly swell the whole, and as a result, post-swelling treatments (dyeing, stretching, etc.) are difficult to perform uniformly, uneven optical characteristics as a polarizing film are likely to occur, and yield as a polarizing film (yield) ) Remains at a relatively low value of about 75% or less.
JP 10-153709 A

The present invention, in view of the situation described above, the PVA film as swelling method of the PVA film through a plurality of guide rollers installed in swelling water guiding the swelling in water (method and apparatus), the whole of the PVA film By providing a material that can swell almost uniformly, and by using this swelling method , it is possible to perform a process such as dyeing and stretching almost uniformly, and to obtain a polarizing film that has almost no uneven optical properties and a higher yield. The main object is to provide a manufacturing method (method and apparatus) for a polarizing film that can be manufactured .

According to the present invention, as described in claims 1 and 6 of the claims, basically, the problem is that the swollen water is removed through the plurality of guide rollers in which the PVA film is placed in the swollen water. In the swelling method and apparatus for the PVA film to be guided, at least one guide roller is constituted by a cylinder (drum) type pressurized water discharge roller having a number of pressurized water discharge holes symmetrically formed on both halves in the axial direction. .

In the method and apparatus for swelling a PVA film according to the first and sixth aspects of the present invention, as described in the second and seventh aspects, the PVA film is placed on the surface of the pressurized water discharge roller constituting at least two guide rolls. It is desirable to guide the turning so that the back surfaces face each other.

In addition, the PVA film swelling method and apparatus according to claim 1 or 2 and claim 6 or 7 according to the present invention, as described in claims 3 and 8 , the pressurized water discharge hole of the pressurized water discharge roller is configured to discharge pressurized water. It is desirable to form it so that it may open to each of the plurality of pressurized water guide grooves extending in the axial direction formed on the surface of the roller at intervals around the axis.

Furthermore, in the method and apparatus for swelling a PVA film according to claims 3 and 8 of the present invention, as in claims 4 and 9 , the axial position of the pressurized water discharge hole in the pressurized water guide groove adjacent to the pressurized water discharge roller. Are preferably shifted from each other. In this case, the shift amount of the position can generally be a half pitch.

Furthermore, in the swelling method and apparatus of the PVA film according to any one of claims 1 to 4 and claims 6 to 9, as described in claims 5 and 10 , the pressurized water discharge roller is formed of a pressurized water supply pipe system. It is desirable to support at the water supply end (tip).

The present invention further includes, as described in claim 11, a step of swelling the PVA film by the method for swelling a PVA film according to any one of claims 1 to 5, a step of dyeing, and a step of stretching. A method for producing a polarizing film is provided.

Furthermore, as described in claim 12, the present invention provides a polarizing film manufacturing apparatus including the PVA film swelling apparatus according to any one of claims 6 to 10, a dyeing tank, and a stretching tank. .

According to the basic configuration of the method and apparatus for swelling a PVA film according to the present invention as set forth in claims 1 and 6 , the entire film is swelled almost uniformly, and the yield of the polarizing film is 90%. It was confirmed that it was improved to the extent of exceeding. Such a high yield is due to the fact that the PVA film introduced into the swollen water is subjected to a swelling action by natural permeation of the swollen water in the same manner as the known method, except for the guide roller comprising the pressurized water discharge roller, while the pressurized water In the guide roller section consisting of the discharge roller, it is forced to swell due to the pressurization and penetration of pressurized water discharged from a number of pressurized water discharge holes and flowing along the surface of the roller. It is estimated that

Moreover, according to the opposing guide structure of the front and back surfaces of the PVA film with respect to the two or more pressure swelling water discharge rollers according to claim 2 and 7 , the PVA film is forcedly swollen by pressure penetration of pressurized water from both surfaces. Under the action, the swelling is more uniform.

According to the opening structure with respect to the pressurized water guide groove of the pressurized water discharge hole of the pressurized water discharge roller according to claim 3 and 8 , since the pressurized water flows toward each end in the axial direction along the pressurized water guide groove, the PVA film is widened. Since it is in a state free from wrinkles and sagging, it is swollen more uniformly.

Furthermore, according to the axial position shift configuration such as the half pitch of the pressurized water discharge holes in the adjacent pressurized water guide grooves according to claim 4 and 9 , the discharge portion of the pressurized water is in a more balanced state. Since the layers become uniform and the PVA film undergoes a uniform widening action, nearly uniform swelling is ensured.

Furthermore, according to the support structure by the water supply end part of the pressurized water supply pipe | tube system of the pressurized water discharge roller of Claim 5 and 10 , since it is not necessary to provide an independent support shaft, a structure can be made compact.

According to the method and apparatus for producing a polarizing film according to claims 11 and 12, dyeing and stretching are performed in a substantially uniform form, and as a result, a polarizing film having almost no unevenness in optical properties is produced in a high yield. be able to.

A preferred embodiment of a method and apparatus for swelling a PVA film according to the present invention will be described below with reference to the drawings.

FIG. 1 shows an outline of the configuration of a preferred embodiment of a method and apparatus for swelling a PVA film, which is a feature of the present invention. In the swelling water 12 in the swelling tank 11, the PVA film 10 on the introduction side is shown. A plurality (four in this case) of pressurized water discharge rollers 15 and one standard conventional guide roller 16 are installed in a zigzag manner on the lower and upper sides from the left to the right. A film introduction roller 17, a standard guide roller 18, and a film lead-out roller 19 are installed on the left side and the right side, and are introduced into the swelling water 12 in the book water tank 11 through the film introduction roller 17. After the film 10 is guided in a zigzag manner so that the front surface and the back surface are alternately opposed to the pressurized water discharge roller 15, a standard guide roller 18 outside the swelling tank 11, a film is passed through the guide roller 16. Those configured to derive to arm derivation roller 19. In addition, after this, the PVA film 10 is induced | guided | derived to a dyeing tank, a drawing tank, etc., and manufactures a polarizing film.

  As shown in FIGS. 2 and 3, each pressurized water discharge roller 15 has a plurality of pressurized water guide grooves 20 formed at equal intervals around the axis on the surface portion. A plurality of outwardly open pressurized water discharge holes 21 are opened at substantially equal intervals at positions symmetrical with respect to the center in the axial direction. The pressurized water discharge holes 21 are opened at positions shifted by a half pitch in the adjacent pressurized water guide grooves 20 and are arranged in a staggered manner as a whole.

  Each of the pressurized water discharge rollers 15 has a pair of left and right water supply end pipe connectors (water supply end pipes) that constitute the water supply end portion of the pressurized water supply pipe system 24 together with the water supply end pipe 25 with the left and right end walls 22 extending concentrically. A connecting pipe 26 is rotatably supported via a bearing 27.

  As for the water supply end pipe 25, as for the pressure water discharge roller 15 located on the lower side in FIG. 1, as for the pressure water discharge roller 15 located on the lower half as shown in FIGS. A number of water supply holes 28 are formed around the axis and spaced in the axial direction in the upper half (corresponding to the state in which the top and bottom in FIGS. In order to suppress the inflow of pressurized water into each of the upper half (see FIGS. 2 and 3) and the lower half where the water supply holes 28 are not formed, a pair of front and rear pressurized water inflow suppression flanges extending over the entire length in the axial direction. 29 is attached.

  In the illustrated embodiment, the PVA film 10 introduced into the swelling water 12 in the swelling tank 11 via the film introduction roller 17 is in the upper and lower sides until reaching the first pressurized water discharge roller 15. Between the pressurized water discharge rollers 15, the water is subjected to a swelling action due to natural penetration of the swelling water 12 in the swelling tank 11, and in each of the pressurized water discharge rollers 15, the pressurized water discharged outwardly through the pressurized water discharge holes 21. By the flow along the pressurized water guide groove 20, while being subjected to a widening action, it is subjected to a forced swelling action by pressure permeation from each of the front surface and the back surface, thereby leading out from the swelling tank 11 through a conventional guide roller 16. It is swollen accurately.

In the PVA film swelling method and apparatus according to the present invention, the pressure water discharged through the pressure water discharge hole 21 of the pressure water discharge roller 15 is generally a minute amount (for example, about 1 mm) from the surface of the pressure water discharge roller 15. ) Pressurized water flow with a small thickness (for example, about 1 mm) between the PVA film and the surface of the pressurized water discharge roller, which is suitable for separating and maintaining a non-contact state (pressure, flow rate, flow rate, etc.) It is possible to discharge under conditions suitable for forming a layer (see particularly FIG. 4).

  The discharge conditions of these pressurized waters can be appropriately set according to the size (thickness, width) of the PVA film 10 and the transport conditions (tension, speed, etc.), the temperature of the swelling water 12 in the swelling tank 11, and the like. The conveyance conditions of these PVA films 10 and the temperature of the swelling water 12 can be adjusted by automatic control.

In addition, the PVA film swelling method and apparatus according to the present invention are configured such that the pressurized water discharge roller can be rotationally driven (for example, a concentric driven gear is attached to the end wall of the pressurized water discharge roller and adjacent to the driven gear). Of course, the present invention can be implemented in various forms, such as engaging a drive gear to be installed, and is not limited to the above form.

  Using a dyeing tank, a stretching tank, a fixing tank, and a drying device together with a swelling tank in which a pressurized water discharge roller having a structure as shown in FIGS. When a PVA film having a width of 2600 mm and a thickness of 80 μm was subjected to swelling, dyeing, stretching, dyeing agent fixing, and drying treatment while controlling the tension and speed, etc., a plurality of polarizing films were produced. As an average yield, about 90% was obtained.

Comparative example

For comparison , a PVA film having the same size as the above is used almost in the same manner as described above by using the same dyeing tank, stretching tank, and the like together with a swelling tank in which a standard guide roller is arranged instead of the pressurized water discharge roller. When a plurality of polarizing films were produced by carrying out treatments such as swelling, dyeing and stretching under the same conditions, the average yield of the polarizing film was about 70%.

BRIEF DESCRIPTION OF THE DRAWINGS It is a structure schematic diagram of suitable one Embodiment of the swelling method and apparatus of the PVA film which concerns on this invention. 2 is a schematic enlarged front view of an embodiment of a water supply end portion of a pressurized water supply pipe system that supports a pressurized water discharge roller located on the lower side and the pressurized water roller in the embodiment shown in FIG. FIG. 3 is a schematic cross-sectional side view of the embodiment shown in FIG. 2 where a PVA film is also shown. FIG. 3 is an enlarged front sectional view of a surface layer portion at a central portion in the axial direction of the pressurized water discharge roller shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 PVA film 11 Swelling tank 12 Swelling water 15 Pressurized water discharge roller 16 Guide roller 17 Film introduction roller 18 Guide roller 19 Film extraction roller 20 Pressurized water guide groove 21 Pressurized water discharge hole 22 End wall 24 Pressurized water supply pipe system 25 Feed water end pipe 26 Feed water end Pipe connector 27 Bearing 28 Water supply hole 29 Pressurized water inflow suppression flange

Claims (12)

A method of swelling a polyvinyl alcohol film that guides the swollen water through a plurality of guide rollers in which the polyvinyl alcohol film is placed in the swollen water, and discharges a plurality of pressurized water symmetrically to both halves in the axial direction. A method for swelling a polyvinyl alcohol film, comprising a cylinder-shaped pressurized water discharge roller having a hole. The method for swelling a polyvinyl alcohol film according to claim 1, wherein the polyvinyl alcohol film is turned and guided to a pressurized water discharge roller constituting at least two guide rolls so that the front surface and the back surface face each other. The polyvinyl alcohol according to claim 1 or 2, wherein a pressurized water discharge hole of the pressurized water discharge roller is opened in each of a plurality of axially extending pressurized water guide grooves formed on the surface of the pressurized water discharge roller at intervals around the axis. How to swell the film. The method for swelling a polyvinyl alcohol film according to claim 3, wherein the axial positions of the pressurized water discharge holes in the adjacent pressurized water guide grooves of the pressurized water discharge roller are shifted from each other. The method for swelling a polyvinyl alcohol film according to any one of claims 1 to 4, wherein the pressurized water discharge roller is supported by a water supply end of a pressurized water supply pipe system. A device for swelling polyvinyl alcohol film that guides the swollen water through a plurality of guide rollers in which the polyvinyl alcohol film is placed in the swollen water, and discharges a plurality of pressurized water symmetrically to both halves in the axial direction. A swelling apparatus for a polyvinyl alcohol film, comprising a cylinder-shaped pressurized water discharge roller having a hole. The swelling device of the polyvinyl alcohol film according to claim 6, wherein the polyvinyl alcohol film is turned and guided to a pressurized water discharge roller constituting at least two guide rolls so that the front surface and the back surface face each other. The polyvinyl alcohol according to claim 6 or 7, wherein a pressurized water discharge hole of the pressurized water discharge roller is opened in each of a plurality of axially extending pressurized water guide grooves formed on the surface portion of the pressurized water discharge roller at intervals around the axis. Film swelling device. The swelling apparatus of the polyvinyl alcohol film of Claim 8 which mutually shifts the position of the axial direction of the pressurized water discharge hole in the pressurized water guide groove which adjoins a pressurized water discharge roller. The apparatus for swelling a polyvinyl alcohol film according to any one of claims 6 to 9, wherein the pressurized water discharge roller is supported by a water supply end of a pressurized water supply pipe system. A method for producing a polarizing film, comprising a step of swelling a polyvinyl alcohol film by the method of swelling a polyvinyl alcohol film according to any one of claims 1 to 5, a step of dyeing, and a step of stretching. The manufacturing apparatus of a polarizing film containing the swelling apparatus of the polyvinyl alcohol film in any one of Claims 6-10, a dyeing tank, and an extending | stretching tank.

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