JP5569791B2 - Raw film for producing optical film, and method for producing optical film - Google Patents

Description

  The present invention relates to a raw film used for producing an optical film. Moreover, this invention relates to the optical film produced from the said raw film, and its manufacturing method.

  Various optical films such as a protective film used for protecting a polarizing film of a polarizing plate provided in a liquid crystal display device and a retardation film for a liquid crystal display device are raw film made of a long resin film having a certain width. In general, the long optical film thus obtained is cut into a predetermined shape according to product specifications to obtain an optical film sheet.

  The raw film may include defective portions that do not meet the required characteristics of the obtained optical film. In such a defective portion of the raw film, for example, in a subsequent process such as a step of cutting the optical film into sheets, the identification of the defective portion is facilitated, and the optical film sheet containing defects can be easily removed. It is common to apply markings so that

  Patent Document 1 discloses a defect marking apparatus that can directly mark a defect portion of a sheet-like product with a pen. Further, Patent Document 2 discloses a defect marking method in which marking defects are provided on both sides in the width direction of a defective portion in the vicinity of the defective portion of the sheet-like product.

JP-A-9-304295 JP 2002-303580 A

  The defect marking method described in Patent Document 1 employs a marking with a pen, that is, a marking method using ink. In the case of such a marking method, in the process after the marking, If the anti-film is treated with chemicals or an adhesive is applied to bond the original film to another optical member, the marked ink may be blurred or disappear.

  The defect marking method described in Patent Document 2 is a method in which marking is performed in the vicinity of a defective portion, as in Patent Document 1, but a marking damage is applied instead of marking with ink. According to such a method, the problem that the marking disappears in the subsequent process can be solved. However, if the vicinity of the defective part is scratched according to this method, when the long original film having been marked is wound up into a roll before the optical film production process, depending on the resin material type of the original film , It was found that scratches were successively transferred to other parts of the original film, and when the resulting optical film was cut out, the portion that could not be used as an optical film sheet increased, resulting in a decrease in yield. . That is, the original film having been marked is generally wound up for transport and then transported to another work place to be used in a process for producing an optical film, which is shown in FIG. Thus, for example, if a marking scratch 3 ′ is made in the vicinity of a defect 2 ′ existing in a long original film 1 ′ made of polyethylene terephthalate, and wound in a roll shape, the marking scratch 3 ′ Scratches are transferred one after another to the part located immediately above or directly below (transfer mark 4 ′ in FIG. 3), and it is found that the transfer extends to the 7th to 9th laps from the position of the marking scratch 3 ′. did.

  The present invention has been made in order to solve the above-mentioned problems, and the object thereof is a raw film for producing an optical film whose defects are indicated by markings, and is a case where the film is once wound up in a roll shape. Even if it exists, it is providing the original film which can obtain the optical film cut out to the sheet | seat with a sufficient yield. Another object of the present invention is a marking method for showing defects of an original film for producing an optical film, where the original film is marked and then wound into a roll. Even if it exists, it is providing the marking method which can obtain the optical film cut out to the sheet | seat with a sufficient yield. Still another object of the present invention is to provide an optical film produced from the original film and a method for producing an optical film using the original film.

The present invention is cut in a direction substantially parallel to the end in the film width direction with respect to the longitudinal direction of the film, a raw film elongated for making optical films is removed, place the defect is present And an original film having scratches for indicating defects at substantially the same position in the film longitudinal direction and at the end in the film width direction closer to the defects .

The raw film of the present invention can have a Martens hardness of 150 N / mm ² or less. Moreover, the raw film of this invention can be comprised from a polyester-type resin film. The raw film of the present invention may be provided with a resin layer laminated on one surface, and the water contact angle of the resin surface may be 70 ° or more. The raw film of the present invention can be a roll-shaped raw film that has been wound into a roll.

  The present invention also provides an optical film produced by cutting and removing a portion including a scratched end portion and a defect-existing portion of the raw film, and the optical film and the optical film. A polarizing plate provided with a polarizing film.

The present invention further provides a method of marking for indicating the defects included in the original film elongated for making optical films, substantially at the same position with respect to location and raw film longitudinal defects are present, and Provided is a marking method including a step of scratching an end in the width direction of a raw film closer to a defect .

Furthermore, the present invention provides a method of producing an optical film from raw long film having a defect, substantially at the same position with respect to location and raw film longitudinal defects are present, and defects by nearly raw A step of scratching the end portion in the film width direction to show the defect, and a step of cutting and removing the scratched end portion in a direction substantially parallel to the longitudinal direction of the original film. A method for producing an optical film is provided.

One preferred embodiment of the method for producing an optical film of the present invention, substantially at the same position in place and raw film longitudinal defects are present, and the end of the closer original film width direction by the defect, the defect A step of applying the first marking by scratching to show the roll, a step of winding the original film on which the first marking has been made into a roll shape, and obtaining a roll-shaped original film, and a roll-shaped original fabric film A step of unwinding the original fabric film, a step of laminating a resin film on the surface of the unrolled original fabric film to obtain a laminated film, a first marking of the laminated film is recognized, and the first marking And applying a second marking from above the resin film to at least a part of the laminated film region at substantially the same position with respect to the longitudinal direction of the laminated film, Cutting and removing the end portion of the laminated film on which the first marking is applied in a direction substantially parallel to the longitudinal direction of the laminated film, and the laminated film on which the second marking is applied. Cutting the sheet, and removing the sheet film on which the second marking is applied.

  According to the present invention, even when the raw film is once wound into a roll, without causing a problem such as the disappearance of the marking in the process after marking the original film, An optical film cut into a sheet can be obtained with a high yield.

It is a figure which shows the original fabric film of this invention typically. The outline which shows a mode that while cut | disconnecting the edge part of the raw film unwound from the roll-shaped original film with the scratch | flaw (1st marking) given to the edge part using a cutting machine, it cut | disconnects into a sheet | seat FIG. It is a schematic diagram which shows the problem of the conventional defect marking method.

Hereinafter, the present invention will be described in detail.
<Original film>
The raw film of the present invention is a film composed of a resin film (usually a transparent resin film) provided with a marking for showing the defect when it has a defect in any part of the film. It is a raw film used for production of an optical film. The “original film” is a long film having a certain width, which is a constituent element of an optical film used for producing an optical film. In the present invention, the optical film is at least an end in the width direction of the original film. It is produced through a step of cutting and removing a portion (usually both ends) in a direction substantially parallel to the longitudinal direction of the original film and a step of cutting and removing a portion including a portion where a defect exists. Usually, the raw film having the marking of the present invention is subjected to an optical film production step in a state of being rolled up into a roll (hereinafter referred to as a roll-shaped raw film). In the optical film production process, a predetermined treatment (surface treatment, pasting with other resin film, stretching, a combination thereof, etc.) is performed on the raw film unwound from the roll-shaped raw film as necessary. The obtained long optical film including the step of applying is usually cut into a predetermined shape according to the product specifications to obtain an optical film sheet.

  The “optical film” produced from the raw film of the present invention means a film-like optical member applied to various optical products. For example, when the optical product is a liquid crystal display device, polarized light A polarizing film constituting the plate, a protective film for protecting the polarizing film; an optical compensation film such as a retardation film; other various optical functional films, etc., which may have a plurality of optical functions.

  In addition, the “defect” of the raw film in the present invention refers to the foreign material such as dust adhering to the film surface or mixed in the film, metal scrap derived from the manufacturing equipment, foreign matter derived from the human body, etc. It means a region that does not satisfy the physical properties (including optical properties, surface shape, etc.) required for the film. As such a defect region, for example, a region where unintended coarse particles exist when the raw film is composed of a resin film and a resin layer (antiglare layer or the like) containing fine particles formed on the resin film. A region where fine particles are not properly dispersed and locally aggregated; a region where fine particles do not exist locally and have no surface irregularities, and the like. The defect of the raw film in the present invention may be a defect that is difficult to identify with the naked eye.

  The raw film of the present invention is an end portion in the film width direction that is cut and removed during the production of an optical film, and there are scratches to show the defects at substantially the same position in the longitudinal direction of the film and where the defects exist. It is characterized by being given. As described above, after marking scratches on the original film, if wound up in a roll shape, there is a problem that the scratches are transferred one after another and the defects are amplified. In the film, the end portion to be cut and removed in producing the optical film is scratched, and therefore, the transferred mark is also present on the end portion. Therefore, the portion used as the optical film It is possible to prevent the defects from being amplified, thereby preventing the yield of the optical film from being lowered due to the transfer of the marking. Also, unlike marking with ink, marking with scratches can eliminate problems such as the disappearance of the marking in the process after marking the original film.

  Here, with reference to FIG. 1, the edge part 5 of the width direction of the raw film 1 cut | disconnected and removed at the time of optical film preparation refers to the part outside an effective width among the width | variety of the original film 1, A scratch 3 for indicating a defect is applied to the end portion 5 which is a portion outside the effective width. “Effective width” means a width region used as an optical film in a raw film. For example, when an optical film having a width of 400 mm and a length (length in a direction perpendicular to the width direction) of 700 mm is obtained from an original film having a width of 1330 mm, as shown in FIG. An optical film is obtained, and therefore the effective width is 1200 mm, and an area of 65 mm (outside the effective width) from both long sides of the original film becomes an end portion to be cut and removed.

  The end to which the scratch is applied may be either one of both ends in the film width direction or both ends, but only on the end closer to the defect. Scratching is preferable because the yield of the finally obtained optical film sheet can be improved. This point will be described in detail later.

  The constituent material and form of the raw film of the present invention are selected according to the type of optical film produced using the raw film (that is, the optical properties of the optical film). Specifically, the raw film of the present invention can be composed only of a resin film (for example, when the optical film is a protective film or a retardation film), or a resin film as a base material. In addition, a resin layer may be laminated thereon. Examples of the resin material constituting the resin film include cellulose resins such as triacetyl cellulose (TAC); polyester resins such as polyethylene terephthalate (PET); (meth) acrylic resins such as polymethyl methacrylate; cycloolefin Examples thereof include olefin resins such as polymers (COP); polycarbonate (PC) resins.

  The resin layer is a layer for imparting predetermined optical properties to the optical film, and examples thereof include an antiglare layer, a hard coat layer, and a light diffusion layer. The resin material constituting the resin layer and the type and blending ratio of additives added as necessary are appropriately selected according to the optical properties required for the resin layer, and conventionally known ones can be adopted. .

  When the raw film of the present invention is provided with a resin layer, the scratch for showing a defect is the end of the surface opposite to the surface on which the resin layer is formed in the resin film as the substrate, or the resin layer Usually, it is applied to the end where the resin layer is not laminated and the surface is exposed.

  Here, in the conventional method of marking with ink, regardless of whether the marking is applied to the end of the film or in the vicinity of the defect, the marking is performed by transferring the marking once the original film having been marked is wound up. This problem is particularly noticeable when the water contact angle on the surface of the resin layer (or the resin film if no resin layer is provided) is large and the surface of the original film is likely to repel ink. Become. In the present invention, since marking is performed by scratching without using ink, the surface of the resin layer (or the resin film if no resin layer is provided) has a large water contact angle, for example, 70 ° or more or 80 °. As described above, even when the angle is 100 ° or more, the marking can be easily recognized in the subsequent process without disappearing.

  In the present invention, the water contact angle of the surface of the original film is such that the surface to be measured is outside and the original film is bonded to a glass substrate using an adhesive. It is a value measured horizontally by setting it on a contact angle meter so that 1 microliter of pure water is dropped on the surface of the measurement object.

  Although the thickness of the raw film of the present invention varies depending on the type of the optical film, it is usually 60 μm or less, preferably 40 μm. The present invention is more advantageous when the thickness of the raw film is smaller. That is, as the thickness of the original film becomes smaller, the scratch hardness becomes smaller, and accordingly, the transfer of marking flaws becomes more prominent. Therefore, in the conventional method in which a scratch for marking is applied in the vicinity of the defect, when the thickness of the original film is small, the problem of the transfer of the marking becomes more remarkable, and the yield of the optical film is significantly reduced due to the transfer. On the other hand, according to the present invention, since the thickness of the original film is small and the transferred mark is markedly transferred, the transferred mark exists on the end portion to be cut and removed. The yield reduction of the optical film due to the transfer can be prevented.

The surface of the raw film of the present invention may have a Martens hardness indicating scratch hardness of 150 N / mm ² or less, 120 N / mm ² or less, and further 100 N / mm ² or less. Even with such a raw film having a relatively low Martens hardness, according to the present invention, as described above, it is possible to prevent a decrease in the yield of the optical film due to transfer. In the present invention, the Martens hardness of the raw film is a value measured under the conditions of maximum load 250 mN, maximum depth 10 μm, load time 60 seconds: indenter shape: Vickers.

  The width of the raw film of the present invention is not particularly limited, but is usually 1000 mm or more, and typical examples include 1330 mm and 1490 mm. The length of the film is not particularly limited, and is, for example, 100 m or more, preferably 10,000 m or less. The raw film of the present invention is usually used for production of an optical film in the form of a roll-shaped raw film that is wound up into a roll.

<Method for producing optical film>
The method for producing an optical film of the present invention is to produce an optical film using the raw film of the present invention, and at least the following steps:
(A) A first marking for applying a scratch to indicate a defect at substantially the same position with respect to a position where the defect exists and the longitudinal direction of the original film at the end in the width direction of the long original film having a defect Process,
(B) an end removing step of cutting and removing the scratched end in a direction substantially parallel to the original film longitudinal direction;
including. The “raw film”, “end” and “defect” mentioned here have the same meaning as described above.

Moreover, the method for producing an optical film of the present invention preferably comprises the following steps:
(C) The sheet | seat making process of removing the sheet | seat film containing the location where a defect exists while cut | disconnecting a raw film into a sheet | seat is included. Hereinafter, each step will be described in detail.

[1] First marking step (A)
In this step, a scratch (first marking) for indicating the defect is located at substantially the same position in the longitudinal direction of the original film at the end in the width direction of the long original film having the defect. ), And is a step of obtaining the raw film according to the present invention. The method of scratching (first marking) the end of a long original film having defects is not particularly limited, but a method using a device similar to the marking device shown in Patent Document 2 is preferable. Specifically, it is arranged above (or below) the unwound film in order from the upstream side in the unwinding direction of the long original film having defects wound in a roll shape, and an image of the film is acquired. An image pickup means for illuminating and an illuminating means arranged at a position facing the image pickup means through the unwound film; a conveyance speed detection means for detecting a carry speed of the unwound film; and an end of the unwound film A marking device provided with a marking means for applying a scratch (first marking); and an air suction means for removing deposits on the film surface after marking, which are optionally installed, can be suitably used.

  The imaging means may have a configuration in which a plurality of cameras are arranged at regular intervals in the original film width direction. The camera includes, for example, a CCD sensor as an image sensor. The image data picked up by the image pickup means is sent to the image processing means for performing predetermined image processing and image processing is performed. The image processing result is transmitted to control means (such as a personal computer) connected to the image processing means.

  The illumination means is installed so that defects can be more reliably detected from an image captured by the imaging means, and performs uniform illumination over the entire width of the original film. As the illumination means, a tubular light emitter such as a fluorescent lamp or a linear light source such as a transmission light is used. A transmission light has a powerful light source such as a metal halogen lamp placed on the end face in the axial direction of a rod-shaped light guide, and guides the light incident on the end surface to the side surface between both end faces, thus functioning as a rod-shaped light source. is there. Further, the laser beam can be spread and irradiated. The light that the illumination means irradiates the original fabric film is set so as to have a wavelength and polarization characteristics that facilitate the detection of defects.

  The transport speed detecting means is for detecting the transport speed of the unwound film, and the output from the transport speed detecting means is from an image processing means that performs predetermined image processing on the image captured by the image capturing means. Are input to the control means.

  The control means determines the presence or absence of a defect from the image processing result and detects the position when the defect exists. In addition, the control means adjusts the timing based on the output from the conveyance speed detection means so as to make a scratch (first marking) at substantially the same position in the longitudinal direction of the original film and the location where the defect exists, Activating the marking means.

  The marking means has a function of attaching a linear scratch (first marking) parallel to the film transport direction to the end surface of the original film, and specifically, the unrolled original film It can be the structure provided with the wound member arrange | positioned on one edge part or both edge part. By bringing the tip of the scratching member into contact with the end surface of the original film, a linear scratch parallel to the film transport direction can be made. A grindstone, a file, a needle, or the like can be used as the scratching member. For example, when the original film is a transparent film, the scratches applied to the end surface of the original film become white scratches that can be detected by optical means or visual inspection. In addition, it is preferable to install a support material for applying an appropriate pressure when the raw film is scratched by the scratching member at a position facing the marking means via the unwound film. As the support material, a rubber roll, a rubber plate, or the like can be used.

  The air suction means is for removing deposits (shavings) on the surface of the original film that is generated when the tip of the scratching member is brought into contact with the end surface of the original film and scratched. It arrange | positions in the conveyance direction downstream of a marking means.

  Here, in the present invention, the marking device operates only the scratching member on the end portion closer to the defect based on the position information of the defect acquired by the control means, and the end closer to the defect. It is preferable to be configured to make a scratch (first marking) only on the part surface. As a result, in the single wafer processing step (C) described later, the number of single optical films to be discarded can be reduced regardless of whether or not a defect is present. The yield of the film sheet can be improved.

  Further, in the present invention, the marking device is configured so that the contact time of the scratching member to the surface of the original film is based on the information on the length of the defect (the range in which the defect exists in the longitudinal direction of the original film) acquired by the control means. It is preferable to be configured so as to attach a scratch (first marking) of approximately the same length as the defect by controlling the above. As a result, by observing the first marking in the post-process, it becomes possible to easily grasp the existence area of the defect in the film longitudinal direction, so that the optical film sheet containing the defect is recovered as a non-defective product. Can be prevented more reliably.

  The raw film (raw film according to the present invention) on which scratches (first marking) indicating defects obtained as described above are applied is usually marked means (in the case of including air suction means, air) The film is wound up by a winding device installed on the downstream side of the suction means) to obtain a roll-shaped raw film. This is because a roll-like form is extremely convenient for transporting the original film to a place where the optical film manufacturing process is performed. The winding process causes the transfer of the marking due to the film being pressed against the unevenness of the film surface caused by the first marking. According to the optical film manufacturing method and the marking method of the present invention, For example, since the transfer of the marking occurs on the end portion that is cut and removed in the end portion removing step (B), the yield of the optical film is not reduced by the transfer.

[2] Edge removal process (B) and single wafer process (C)
In the end removing step (B), the original film is unwound from the roll-shaped original film, and the end on which the scratch (first marking) is applied is in a direction substantially parallel to the longitudinal direction of the original film. It is a process of cutting and removing. The end portion removed in this step may be at least an end portion that has been scratched (first marking), but normally, even if there is an end portion that does not have a scratch, the effective width Both outer ends are cut and removed. A sheet-fed process (C) is a process of removing the sheet | seat film (optical film sheet | seat body) including the location where a defect exists while cut | disconnecting a raw film into a sheet | seat.

  FIG. 2 shows an example of a raw film 1 unwound from a roll-shaped raw film having scratches (first markings) 3 on the end (or, as will be described later, a predetermined treatment is applied to the original film). It is the schematic which shows a mode that the edge part 5 of the applied film is cut | disconnected using the cutting machine 10, and the raw film 1 is cut | disconnected to a sheet | seat. As shown in FIG. 2, the edge cutting in the edge removing step (B) and the step of cutting into single sheets in the sheet forming step (C) are performed simultaneously using a cutting means such as a cutting machine. Is preferred. This is because, if the sheet separation step (C) is performed after the end portion is cut and removed by the edge removal step (B), it may not be possible to determine which region of the optical film has a defect. . Therefore, in the case of performing the sheet separation step (C) after cutting the end portion, after performing sheet separation without removing the cut end portion, the sheet film including a portion where a defect exists is obtained. It is preferable to remove the cut end along with the removal. After cutting into pieces, it is possible to cut the ends, and then to remove the cut ends together with the removal of the sheet film including the location where the defect exists.

  As the cutting machine used for cutting the edge and making the optical film into a single sheet, a generally used cutting machine such as a vertical cutting machine using a razor blade or a cutting machine using a rotating round blade can be used. . Further, when the required processing accuracy is low, generally used means such as scissors and a cutter knife can be used for cutting.

For example, the removal of the sheet film (optical film sheet) including the portion where the defect exists in the sheet separation step (C) can be performed as follows.
(A) The optical film sheet disposed in a position having no scratch (first marking) in the width direction among the optical film sheets manufactured by cutting the end portion and forming a sheet. While collecting all the optical film sheets 20a in FIG. 2 as non-defective products, the optical film sheets (optical film sheets in FIG. 2) arranged at positions having scratches (first markings) in the width direction. The bodies 20b and 20c) are all removed as defective and discarded.
(B) Among the optical film sheets produced by cutting and sheet-cutting the end portions, the optical film sheet disposed at a position having no scratch (first marking) in the width direction. While all the optical film sheets 20a in FIG. 2 are collected as non-defective products, the optical film sheets disposed at positions having scratches (first markings) in the width direction are arranged in the film width direction. Only half (or almost half) of the optical film sheet that is close to the end having the scratch (first marking) is removed as a defective product, discarded, and has a scratch (first marking). Collect the half (or almost half) far from the end as a good product. That is, referring to FIG. 2, the side near the end portion having the scratch (first marking) among the optical film sheets 20 b and 20 c arranged at the position having the scratch (first marking) 3. The optical film sheet 20b that is approximately half of the optical film is removed and discarded, and the optical film sheet 20c that is approximately half of the far side is collected as a non-defective product.

  In the above method (b), based on the position information of the defect acquired by the control means, only the scratching member on the end nearer to the defect is operated, and only the end surface closer to the defect is scratched. This is a technique employed when the first marking step (A) is performed using a marking device configured to attach (first marking). According to the above method (b), an optical film sheet having no defects (the optical film sheet 20c in FIG. 2) can be collected as a non-defective product, so that the yield can be further improved. it can.

  The presence / absence of a flaw (first marking) and the position and length thereof can be confirmed visually or using optical means. Moreover, the collection of non-defective products and the removal of defective products of the optical film sheet may be performed manually or may be automated. The size of the optical film sheet is, for example, about 300 to 1500 mm in length and about 300 to 1500 mm in width.

[3] Other processes (i) Bonding process (D)
In the method for producing an optical film of the present invention, scratches (first marking) were applied between the first marking step (A), the edge removing step (B), and the sheet separation step (C). You may provide the bonding process (D) which bonds another resin film on the surface of an original fabric film, and obtains a laminated | multilayer film. The other resin film is bonded by unwinding the original film from the roll-shaped original film obtained in the first marking step (A), and laminating the other resin film via an adhesive or an adhesive. If necessary, the drying and / or curing treatment can be performed.

  The number of other resin films to be bonded to the raw film is not limited to 1 and may be 2 or more. When two or more resin films are bonded, these resin films may be bonded simultaneously or sequentially. Moreover, another resin film may be further bonded on the other resin film bonded to the surface of the raw film. Moreover, you may paste optical members, such as an adhesive layer, with the resin film instead of the resin film.

  Examples of other resin films to be bonded to the raw film include, for example, a surface protective film for temporarily protecting the surface of the optical film formed from the raw film until the time of use, and the original film Examples thereof include other optical films having optical characteristics different from those of the optical film formed from the anti-film. The other optical film is not particularly limited, and examples thereof include a polarizing film. As the surface protective film, for example, a polyester resin film such as a polyethylene terephthalate film or a polyolefin resin film such as a polyethylene film can be used.

  After bonding a polarizing film as another optical film to an original film through an adhesive, the resulting laminated film is subjected to an edge removing step (B) and a sheet-fusing step (C), thereby polarizing the film. A polarizing plate in which an optical film derived from an original film (which can be a protective film or a retardation film) is laminated on the film can be obtained. As the polarizing film, a polarizing film made of a polyvinyl alcohol resin in which a dichroic dye (for example, iodine) is adsorbed and oriented and uniaxially stretched is preferably used. In addition, when an original fabric film consists of a resin film and the resin layer laminated | stacked on this resin film, a polarizing film is bonded by the surface on the opposite side to the side which has the resin layer in a resin film.

  Moreover, the manufacturing method of the optical film of this invention is the roll original obtained by the 1st marking process (A), without including the bonding process (D) prior to bonding with another resin film. A step of performing various treatments on the raw film unwound from the anti-film may be included. Examples of such treatment include easy adhesion treatment (corona treatment, etc.) for improving adhesion to other resin films, stretching treatment, and the like.

(Ii) Second marking step (E)
The second marking step (E) is a laminated film obtained by bonding another resin film to the raw film unwound from the roll-shaped raw film obtained in the first marking step (A). This is a step of applying a second marking different from the first marking on the other resin film. The second marking is applied using, for example, ink.

  When the second marking step (E) is included, the optical film manufacturing method of the present invention includes, for example, the following steps in the following order.

(A) A first marking for applying a scratch to indicate a defect at substantially the same position with respect to a position where the defect exists and the longitudinal direction of the original film at the end in the width direction of the long original film having a defect Process,
(D) A bonding step in which a laminated film is obtained by bonding a resin film on the surface of the original film subjected to the first marking;
(E) Recognizing the first marking of the laminated film, and at least part of the laminated film region at substantially the same position as the first marking and the longitudinal direction of the laminated film, the second marking from above the resin film Applying the second marking process,
(B ′) an end portion removing step of cutting and removing the end portion of the laminated film on which the second marking has been applied in a direction substantially parallel to the longitudinal direction of the laminated film; ') A sheet forming process of cutting the laminated film with the second marking into sheets and removing the sheet film with the second marking.

  About a 1st marking process (A) and a bonding process (D), it is as above-mentioned, and description here is abbreviate | omitted. In addition, as another resin film bonded to the original fabric film, typically, the surface of the optical film formed from the above-described original fabric film is temporarily protected until the time of use. It can be a surface protective film or the like.

  In the second marking step (E), a scratch (first marking) applied to the laminated film is recognized, and at least a part of the laminated film region at substantially the same position as the first marking and the laminated film longitudinal direction is recognized. Then, marking is performed on the resin film using ink or the like. Here, “at least a part of the laminated film region” means that the second marking is applied at least within the effective width of the laminated film, and is substantially at the same position as the first marking in the longitudinal direction of the laminated film. This includes the case where the second marking is applied over the entire width of the laminated film region and the case where the second marking is applied to a part of the effective width. The second marking may or may not be applied to the end of the laminated film to be cut and removed (outside the effective width).

The second marking can be applied, for example, as follows.
(A ′) The second marking is applied over the entire width of the laminated film region at substantially the same position as the first marking and the laminated film longitudinal direction.
(B ′) The second marking is applied only to the half (or substantially half) of the side close to the end having the first marking in the laminated film region at substantially the same position as the first marking and the laminated film longitudinal direction. The second marking is not applied to the half (or approximately half) far from the end having the first marking.

  The above method (b ′) is based on the position information of the defect acquired by the control means, and operates only the scratching member on the end closer to the defect, and only on the end surface closer to the defect. This is a technique employed when the first marking step (A) is performed using a marking device configured to make a scratch (first marking). According to the above method (b ′), the optical film sheet having no defect can be collected as a non-defective product, so that the yield can be further improved.

  The shape of the second marking is arbitrary, and can be, for example, a line extending in the laminated film width direction. By performing the second marking with ink or the like within the effective width, it is possible to more easily sort the non-defective / defective products of the optical film sheet in the subsequent process, and to improve the efficiency of the sorting work. Can do.

  Recognition of scratches (first markings) and second markings made on the laminated film can be carried out visually and manually. However, you may use the apparatus which performs these automatically.

  The edge removal step (B ′) and the sheet separation step (C ′) are the same as the edge removal step (B) and the sheet separation step (C), respectively. However, in the above-described single wafer process (C), defective products are selected and removed based on the first marking, whereas in the single wafer process (C ′), based on the second marking. Sort out and remove defective products. In other words, in the sheet forming step (C ′), the optical film sheet having the second marking may be removed and discarded.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited by these examples. Measurement of the Martens hardness and contact angle with water of the raw film was performed by the following method. The Martens hardness and the water contact angle were measured on both the base film surface and the resin layer surface of the raw film.

(1) Measurement of Martens hardness With the surface to be measured facing outside, the raw film is bonded to a glass substrate using an adhesive, and this measurement sample is made by Fischer Instruments Co., Ltd. so that the surface to be measured is the top surface. Was set horizontally on a measurement stand of “Fischer Scope H2000”, and Martens hardness was measured under the following conditions.
Maximum load: 250mN
Maximum depth: 10 μm,
Loading time: 60 seconds,
Indenter shape: Vickers.

(2) Measurement of water contact angle The surface of the measurement object is outside and the raw film is bonded to a glass substrate using an adhesive, and this measurement sample is contact angle meter so that the measurement object surface is the top surface. It was set horizontally on an image processing contact angle meter “FACE CA-X type” manufactured by Kyowa Interface Science Co., Ltd., and 1 microliter of pure water was dropped on the surface of the measurement object, and the contact angle with water was measured.

[Preparation of a roll-shaped raw film having scratches (first marking) indicating defects]
<Example 1>
While the film is continuously unwound from a roll-shaped polyethylene terephthalate film (PET) (Diafoil, manufactured by Mitsubishi Plastics, Inc.) having a width of 1330 mm, a length of 3500 m, and a thickness of 38 μm as a base film, pentaerythritol triflate on one side A step of forming a coating layer for applying a UV curable resin composition comprising acrylate and polyfunctional urethanized acrylate (reaction product of isophorone diisocyanate and pentaerythritol triacrylate) as a main component, a coating layer by irradiating with UV rays By continuously curing the step of forming a resin layer A having a thickness of 6 μm on the unwound film and the step of winding up the film (raw film) on which the resin layer A is formed. A roll-shaped raw film was obtained.

Next, while continuously unwinding the film from the roll-shaped raw film, the defect is detected through the above-described marking device (a device similar to the device described in Patent Document 2), and a scratching member using a file is used. Thus, scratches (first markings) [length of about 20 mm] were applied at substantially the same position in the longitudinal direction of the film as the position where the defect exists at the end in the width direction of the film (position of 20 mm from the end face). . The surface to be scratched was the surface opposite to the surface provided with the resin layer A. The marking apparatus used has a CCD camera as an image pickup means, a transmission light as an illumination means, and further includes a conveyance speed detection means, and a marking means having the two scratching members on both ends of the unwound film. , An image processing device, a control device (personal computer) and air suction means. Further, the marking device operates only the scratching member on the end portion closer to the defect based on the position information of the defect acquired by the control means, and scratches only the end surface closer to the defect ( The first marking) is applied. By continuously winding up the raw film having scratches passed through the marking device, a roll-shaped raw film having scratches (first marking) indicating defects was obtained. In addition, the number of defects (number of first markings) of the raw film was 0.28 / m ² . Moreover, the defect in a present Example, the following Example, and a comparative example means the part where the optical characteristic is mainly non-uniform | heterogenous, but the thing by the metal waste derived from an installation or the dust derived from an environment is also included. Such a defective portion looks brighter or darker than the surroundings in an image acquired by a CCD camera.

<Example 2>
An ultraviolet curable resin composition comprising, as a main component, pentaerythritol triacrylate, tris (2-acryloxyethyl) isocyanurate and polyfunctional urethanized acrylate (reaction product of isophorone diisocyanate and pentaerythritol triacrylate). Roll-shaped raw fabric film having scratches (first markings) in the same manner as in Example 1 except that the thickness of the resin layer (resin layer B) is changed to 8 μm. Got.

<Example 3>
A roll-shaped raw material having a scratch (first marking) in the same manner as in Example 2 except that a triacetyl cellulose film (TAC) having a width of 1330 mm, a length of 1000 m, and a thickness of 40 μm was used as the base film. An anti-film was obtained.

<Example 4>
A roll-shaped raw film having scratches (first marking) was obtained in the same manner as in Example 2 except that a triacetylcellulose film having a width of 1330 mm, a length of 1000 m, and a thickness of 60 μm was used as the base film. Obtained.

<Comparative Example 1>
Except that the position of the scratch (first marking) is not the edge of the original film, but near the defect (two scratches with a width of about 20 mm so as to sandwich the defect existing position), the same as in Example 1. Thus, a roll-shaped raw film having scratches (first marking) was obtained.

<Comparative example 2>
Except that the position of the scratch (first marking) is not the edge of the original film, but near the defect (two scratches with a width of about 20 mm so as to sandwich the defect existing position), the same as in Example 2. Thus, a roll-shaped raw film having scratches (first marking) was obtained.

<Comparative Example 3>
Except that the position of the scratch (first marking) is not the edge of the original film but near the defect (two scratches with a width of about 20 mm so as to sandwich the defect existing position), the same as in Example 3. Thus, a roll-shaped raw film having scratches (first marking) was obtained.

<Comparative Example 4>
Except that the position of the scratch (first marking) is not the edge of the original film but near the defect (two scratches with a width of about 20 mm so as to sandwich the defect existing position), the same as in Example 4. Thus, a roll-shaped raw film having scratches (first marking) was obtained.

  Table 1 shows the Martens hardness and water-resistant contact angle of the raw film obtained in each of the Examples and Comparative Examples (the film was unwound and cut out from a roll-shaped raw film having scratches).

  When the roll-shaped raw film having scratches (first marking) obtained in each Example and Comparative Example was unwound and the transfer of the marking was confirmed, the pitch from the first marking is shown in Table 2. Marking transfer was confirmed by the number. However, in each of Examples 1 to 4, since the scratch (first marking) is applied to the end of the film, that is, outside the effective width, a product (optical film) obtained using the original film by marking transfer No decrease in yield of single wafers occurs. On the other hand, the number of defects increased about 10 times in Comparative Examples 1 and 2, about 7 times in Comparative Example 3, and about 5 times in Comparative Example 4 by winding the raw film into a roll.

  Table 2 shows the marking transfer status and the impact on the product yield in each example and comparative example.

[Preparation of polarizing plate]
<Example 5>
While the film is continuously unwound from the roll-shaped raw film having scratches (first marking) obtained in Example 1, a polarizing film, triacetylcellulose is formed on the surface opposite to the surface provided with the resin layer. After carrying out the process of pasting the resin film (thickness of 80 μm) made of the adhesive layer through the adhesive, and the process of pasting the surface protective film with the adhesive on the surface provided with the resin layer The adhesive film is coated on the resin film made of triacetyl cellulose and a releasable separate film is bonded. Then, the obtained polarizing plate with the adhesive layer is used as a razor blade. Using the used vertical cutter, both ends in the film width direction (portions outside the effective width) are cut, and the product (polarized light with adhesive layer) is 401 mm in the width direction and 706 mm in the direction perpendicular to the width direction. Three pieces in the width direction Maihatai) was continuously cut. At this time, the scratch outside the effective width (first marking) flowing along with the product is visually detected, and when the scratch (first marking) is discovered, The product with the (first marking) and the middle product was discarded as defective. As a result, defective products were completely eliminated. The yield reduction due to the discard of the two sheets in the part having the scratch (first marking) was 16%.

<Comparative Example 5>
A polarizing plate sheet with pressure-sensitive adhesive layer was obtained in the same manner as in Example 5 except that the roll-shaped raw film having scratches (first marking) in Comparative Example 1 was used. Although defective products could be eliminated completely, the transfer of the marking occurred, and the yield reduction due to discarding defective products with scratches was 80%.

  1, 1 'original film, 2' defect, 3 scratch, 3 'marking flaw, 4' transfer mark, 5 edge of original film width direction, 10 cutting machine, 20a, 20b, 20c optical film sheet Leaf body.

Claims (9)

It is a long original film for producing an optical film by cutting and removing an end in the film width direction in a direction substantially parallel to the film longitudinal direction,
Substantially at the same position in place and the film longitudinal defects are present, and the end portion of the film width direction closer to the defect, the raw fabric film having a wound for indicating the defect. The raw film according to claim 1, which has a Martens hardness of 150 N / mm ² or less. The raw film of Claim 1 or 2 comprised from a polyester-type resin film. The raw film in any one of Claims 1-3 provided with the resin layer laminated | stacked on one surface. The raw film according to claim 4 , wherein a contact angle with water on the surface of the resin layer is 70 ° or more. The raw film according to any one of claims 1 to 5 , which is wound into a roll. A marking method for indicating a defect of a long original film for producing an optical film,
Marking method comprising the step of substantially the same position, and subjected to scratch the end of the closer original film width direction by the defect with respect to location and raw film longitudinally before Symbol defect exists. A method for producing an optical film from a long original film having defects,
A step substantially at the same position, and the end of the closer original film width direction by the defect, performing wounds to indicate the defect with respect to location and raw film longitudinally before Symbol defect exists,
Cutting and removing the scratched end in a direction substantially parallel to the original film longitudinal direction; and
The manufacturing method of the optical film containing this. A method for producing an optical film from a long original film having defects,
Substantially at the same position in place and raw film longitudinally before Symbol defect exists, and the end of the closer original film width direction by the defect, the first marking by wounding to indicate the defect Applying process;
Winding the raw film with the first marking into a roll, and obtaining a roll-shaped raw film;
A step of unwinding the original film from the roll-shaped original film,
A step of laminating a resin film on the surface of the unrolled raw film to obtain a laminated film;
Recognizing the first marking of the laminated film, and at least part of the laminated film region at substantially the same position as the first marking and the longitudinal direction of the laminated film, from above the resin film, A process of marking,
Cutting and removing the end of the laminated film subjected to the second marking in the direction substantially parallel to the longitudinal direction of the laminated film; and
Cutting the laminated film subjected to the second marking into sheets, and removing the sheet film subjected to the second marking;
The manufacturing method of the optical film containing this.

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