JP4566710B2 - Optical film inspection base paper and inspection method - Google Patents

Description

The present invention relates to a base paper for inspection of an optical film having a coating layer such as an optical functional layer. Specifically, the back surface of the optical film to be inspected (the one having a coating layer is the non-coating layer side). in, for preferred inspection by which can attach homogeneously adhesion without causing tunnel and bubbles due to involvement of air is formed, the coating unevenness of the presence or absence and the coating layer of the coating layer, such as abrasion of the surface fluoroscopy An inspection base paper and an inspection method using the same can be clearly discriminated whether or not it looks homogeneous or uniform (homogeneity).

As a method of detecting the thickness unevenness of the coating film provided on the surface of the substrate, for example, the wavelength relative to the thickness of the thin film on the subject, such as the film thickness unevenness of the resist applied to the surface of the liquid crystal glass substrate Illumination light of a light beam having a wide width and a small coherence length is irradiated and illumination light of a light beam having a narrow wavelength width and a large coherence length with respect to the first image IA from the subject and the thickness of the thin film on the subject. The second image IB from the subject is imaged by the imaging device 9, and the first image IA and the second image IB are taken into the image processing unit 15 and the first and second images are taken. A method has been proposed in which only a film thickness unevenness can be reliably detected by executing a predetermined calculation between IA and IB and generating an image IC in which the influence of the background of the subject is eliminated (Patent Document 1). .
JP-A-10-213552

However, the detection method described in Patent Document 1 is a method for accurately measuring thickness spots, and it is necessary to use a precise optical device for measurement. In the present invention, a transparent film is used as a base film. on the surface of the light scattering layer, it can be easily inspected for optical film of order to be embedded in an optical system provided an optical functional layer such as the antiglare layer as a coating layer at the manufacturing site of the optical film as a The present invention relates to a simple and practical inspection method that can be performed and an inspection base paper used for the inspection method.

Whether or not a coating layer (optical functional layer) is provided on the optical film (the presence or absence of the coating layer), and the presence or absence of smears or scratches on the coating layer (homogeneity of the coating layer) depends on the optical system. Significantly affects evaluation. However, these optical films are substantially transparent and cannot be easily seen with the naked eye. In particular, since the thickness of the coating layer of the optical film is thin, the presence or absence of the coating layer and homogeneity It is virtually impossible to discriminate gender.

Therefore, conventionally, the target optical film has been seen obliquely, or black paper or the like has been inspected on the back surface. However, in the above method, even if black paper or the like is overlapped on the back surface of the target optical film, an air layer is generated at the interface between the film and black paper, or the entire surface is reflected by reflected light on the surface of black paper or the like. Since it became whitish, the presence or absence of the coating layer and the evaluation of the homogeneity were not sufficient. Therefore, as an improved method, an adhesive layer is provided on the surface of the black paper or the like and attached to the back surface of the target optical film so that the influence of the air layer is avoided. Yes.

  The inspection method for attaching black paper or the like to the back surface of the target optical film with the pressure-sensitive adhesive layer interposed is basically an air layer between the back surface of the target optical film and the surface of the base paper. Although it is possible to avoid the occurrence of such a phenomenon, equipment such as a nip roller for intimately adhering and sticking together is usually not provided when the inspection is performed as needed during the process. Therefore, the bonding is practically hand-bonded, and air is entrained between the back surface of the target optical film and the black pressure-sensitive adhesive layer to form a tunnel-like non-adhered portion (hereinafter simply referred to as a tunnel) or Bubbles and the like are generated, and it is actually difficult to make them adhere closely. In order to remove the above tunnels and bubbles, once the optical film and the inspection base paper are peeled off and then attached again, the adhesive provided on the surface of the base paper is removed from the optical film. It remains on the back surface and becomes a so-called adhesive residue, causing haze (faint) and lowering transparency, making it difficult to accurately determine the presence or absence and uniformity of the coating layer as a whole. In particular, when the inspection area is a large area, the adverse effects of tunnels and bubbles are more remarkable.

  The present invention avoids the above-mentioned problems, and a preferable inspection body is formed by being able to adhere and adhere uniformly to the back surface of the optical film to be inspected without causing tunnels and bubbles due to air entrainment. Therefore, an object of the present invention is to provide an inspection base paper in which the presence or absence and uniformity of a coating layer can be clearly discriminated.

The first gist of the present invention is a thermoplastic elastomer comprising a block segment comprising a block of a styrene monomer and a block of a rubber monomer on the surface of a substrate layer which is substantially opaque and has a surface reflectance of 10% or less. And an optical film inspection base paper having an adhesive layer comprising an adhesive composition comprising a main component and a plasticizer.

The second gist of the present invention is characterized in that the above-mentioned inspection base paper is attached to the back surface of the optical film, and the presence and uniformity of the coating layer of the optical film is determined by interference fringes appearing on the coating layer side. an inspection method of an optical film to.

  Tunnel by entraining air on the back of an optical film to be inspected, such as an optical film with a transparent film as a base film and a coating layer having an optical function such as a light scattering layer and an antiglare layer on the surface. In addition, since a preferable inspection body is formed by being able to adhere and stick together uniformly without generating bubbles, the presence or absence of the coating layer and the homogeneity are observed according to the degree of appearance of interference fringes. Thus, it is possible to easily and accurately discriminate without being disturbed by the hue of the optical film and the light from the back surface. In addition, the method of inspecting the coating spot of the coating layer based on the appearance of interference fringes generated using the inspection base paper of the present invention is particularly useful when the thickness of the coating layer is several μm or less.

  The inspection base paper of the present invention is formed by laminating an adhesive layer on the surface of a base material layer. This base material layer is a layer constituting an optical background for improving the presence / absence of a coating layer, which is a functional layer of an optical film to be inspected, and the determination accuracy of homogeneity.

  The material constituting the base material layer is not particularly limited. For example, in addition to polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyolefin resins, polyamides Plastics such as resins, polycarbonate resins, polyimide resins, acrylic resins, polyvinyl chloride resins, or a mixture of two or more of them, cellophanes, paper, wood, metal, and ceramic plates Can be mentioned.

(Base material layer)
The shape of the substrate layer is not particularly excluded as long as it can be used as a backing or base for the presence or absence of a coating layer of the target optical film and for homogeneity evaluation. For example, a thin film of about 10 μm From 10 to 10 mm or more, it may be a plate-like material, may be a flexible material from another point of view, and may be a rigid material with little or no flexibility. The biaxially stretched polyester film is flexible from the viewpoints of handling and price when used at any time in unspecified places such as optical film manufacturing sites. Is practical. The thickness is usually about 10 to 500 μm and practically about 50 to 200 μm. Further, from the viewpoint of discriminability, it is better that the whole is opaque or the optical density D is large, for example, 2 or more, preferably 4 or more. Moreover, the one where the surface reflectance of said base material layer is smaller is preferable, for example, 10% or less, Preferably it is 7% or less. When the surface reflectance is large, the reflected light is in the way, and it becomes difficult to determine the pattern due to the presence or absence of the coating layer and the interference fringes due to the coating spots. Further, the hue of the surface of the base layer is selected according to the hue of the optical film, but it is preferable that the pattern due to the interference fringes is easily discriminated. For example, in the case of a colorless optical film, black is preferable. Adopted.

As a method of coloring the hue of the base material layer to black or other hues, carbon black fine particles, fine particles of other hues and / or pigments are kneaded into the base layer resin inside the material constituting the base material layer. mETHOD, and carbon black particles to the surface of the base material layer, how to form fine particles and / or containing layer of pigment and other colors can be cited. The method of forming the latter coating layer is practical when the amount of production per time is small or the type of hue is large, and the substrate obtained by the latter method generally has a surface reflectance. Can be small. Hereinafter, an example in which a biaxially stretched polyethylene terephthalate film is used as a material constituting the base material layer and a layer containing carbon black fine particles is formed on the surface thereof will be described.

The method for forming the carbon black fine particle-containing layer is not particularly limited, but it is usually formed by applying and drying a black binder resin liquid in which carbon black fine particles are mixed and dispersed. Although it does not specifically limit as said binder resin, A well-known resin can be used, For example, polyester-type resin, urethane type resin, polyester-polyurethane resin, polyether polyurethane resin, acrylic-polyol-type resin, polyolefin Among these, a combination of a polyisocyanate, a polyisocyanate, an epoxy, or a melamine can be used. Among them, a combination of an acrylic polyol as a main component resin and an isocyanate curing agent as a curing agent can be preferably exemplified.

The carbon black fine particles usually have an average particle diameter of 10 to 500 nm, but a relatively fine one of 20 to 50 nm is preferable. The content of the carbon black fine particles contained in the solid content of the paint is usually about 5 to 70% by mass, and among them, those with 30 to 60% by mass are easy to use. The thickness of the carbon black fine particle-containing layer is usually 2 μm or more from the viewpoint of reflectivity and light shielding properties, but 10 μm or less is sufficient, and if it exceeds 10 μm, the effect is not improved so much and economically. Disadvantageous. Practically, it is 4-6 μm.

  When the surface of the base material layer sheet produced as described above is low in adhesiveness with the pressure-sensitive adhesive layer described later, the surface is subjected to an easy adhesion treatment, for example, corona treatment, plasma treatment, blast treatment, etc. if necessary. Surface treatment and / or anchor coating treatment can be performed.

The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is composed of a pressure-sensitive adhesive composition mainly composed of a thermoplastic elastomer and a plasticizer, and further, if necessary, in order to reinforce adhesion with the base material layer. The adhesive composition described below can be blended.

The thermoplastic elastomer and plasticizer constituting the above-mentioned adhesive composition are a thermoplastic elastomer selected from the following thermoplastic elastomers, and are added to the thermoplastic elastomer to be plasticized, thereby reducing cohesive force and self-adhesion. It is selected in combination with a plasticizer selected from the following plasticizers that improve the properties.

  Although it does not restrict | limit especially as said thermoplastic elastomer, For example, what is comprised by the block segment which consists of a block of a styrene monomer and a block of a rubber monomer can be mentioned. Specific examples of such thermoplastic elastomers include polystyrene-polyisoprene-polystyrene (SIS), polystyrene-polybutylene-polystyrene (SBS), polystyrene-poly (ethylene / butylene) block-polystyrene (SEBS), polystyrene-poly (ethylene / ethylene / polyethylene). Examples include propylene) block-polystyrene (SEPS), polystyrene-polyisoprene (SI), polystyrene-polybutylene (SB), and polystyrene-poly (ethylene / propylene) block (SEP).

The degree of polymerization of the elastomer can be appropriately selected according to the type of plasticizer to be added, the amount added, and the properties expected as an adhesive. For example, in the case of SEBS, the mass average molecular weight is usually 15,000 to Those having 500,000 are preferably used, and those having 100,000 to 500,000 are more preferably used.

  In addition, the plasticizer is selected so as to be effective in adding self-adhesion to the elastomer, and as such a plasticizer, the thermoplastic elastomer component used is a polystyrene phase. In the case of having a rubber phase, a high molecular weight compound having a high affinity for the rubber phase and a low affinity for the polystyrene phase is preferred, and preferred examples of the plasticizer include naphthenic oil and / or liquid paraffin.

  As said naphthenic oil, that whose flash point is 100-300 degreeC is preferable, and the thing of 150-280 degreeC is more preferable. The pour point is preferably -30 to -5 ° C, more preferably -25 to -10 ° C. Moreover, that whose specific gravity is 0.83-0.87 is preferable, and what is 0.837-0.868 is more preferable. Furthermore, the thing whose carbon number is 3-8 is preferable, and the thing of 5-6 is more preferable.

  On the other hand, in the case of liquid paraffin, the flash point is preferably 100 to 300 ° C, more preferably 150 to 280 ° C. The pour point is preferably -30 to -5 ° C, more preferably -25 to -10 ° C. In addition, the specific gravity is preferably 0.89 to 0.91, and more preferably 0.8917 to 0.9065. Furthermore, that whose carbon number is 20-35 is preferable, and the thing of 21-33 is more preferable.

The mixing ratio of the thermoplastic elastomer and the plasticizer in the main component constituting the pressure-sensitive adhesive component is usually 5:95 to 95: 5, preferably 10:90 to 90:10 as a mass ratio. The

The adhesive composition used for improving adhesiveness by mixing with the above-mentioned adhesive composition includes a main component having excellent compatibility with the above-mentioned adhesive composition, and an intermolecular amount of the main component. A composition with a crosslinking agent having a crosslinking property is preferred.

  Specific examples of the main component of the adhesive composition include carboxylic acid-modified thermoplastic elastomers. As such a carboxylic acid-modified thermoplastic elastomer, various carboxylic acid-modified styrene-based thermoplastic elastomers can be used. Examples of the carboxylic acid modification include aliphatic saturated monocarboxylic acids such as propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, vivalic acid, lauric acid, myristic acid, palmitic acid, stearic acid; succinic acid, Aliphatic saturated dicarboxylic acids such as glutaric acid, adipic acid, hymelic acid, suberic acid, azelaic acid and sebacic acid; aliphatic unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, oleic acid; and , May be derived from an aliphatic unsaturated dicarboxylic acid such as maleic acid, fumaric acid, citraconic acid or mesaconic acid. Among these, those modified with an aliphatic unsaturated dicarboxylic acid are preferable, and those modified with maleic acid are more preferable.

  The carboxylic acid-modified thermoplastic elastomer may be, for example, a hydrogenated carboxylic acid-modified thermoplastic elastomer, such as a hydrogenated carboxylic acid-modified styrene-butadiene elastomer, specifically a maleic acid-modified SEBS elastomer. Is mentioned. When the hydrogenated carboxylic acid-modified styrene-butadiene elastomer is used as the hydrogenated thermoplastic elastomer, the melt index is, for example, 2.5 to 25 g / 10 min under the conditions of 200 ° C. and 5 kg. Some are preferred, more preferably 3-7 g / 10 min. In the present invention, the hydrogenation rate is preferably substantially 100%, but may be less than 100% as long as the effects of the present invention can be obtained.

  When the carboxylic acid-modified SEBS elastomer is used, the mass ratio of (styrene) :( ethylene + butylene) is preferably, for example, 10:90 to 40:60, and 20:80 to 30:70. More preferably. Furthermore, the acid value of the carboxylic acid-modified thermoplastic elastomer is preferably 2 to 10. Within the range, those having an acid value of less than 3 can be colorless and transparent, while those having an acid value of 3 to 10 can be yellowish.

Examples of commercially available carboxylic acid-modified thermoplastic elastomers or hydrogenated products thereof include Tuftec M1911, M1913, and M1943 (trademark, manufactured by Asahi Kasei Kogyo Co., Ltd.) and FG-1901X (trademark, Clayton polymer product).

  The crosslinking agent used in combination with the main agent component in the adhesive composition is not particularly limited as long as it has crosslinkability between the carboxylic acid-modified thermoplastic elastomer molecules as the main agent component, depending on the main agent component. For example, coronate HL (hexamethylene diisocyanate-HDI-TMP adduct, trademark, product of Nippon Polyurethane Industry Co., Ltd.) and aziridine-based curing agent BXX5134 (manufactured by Toyo Ink Manufacturing Co., Ltd.) may be preferably mentioned. it can.

  The compounding ratio of the carboxylic acid-modified thermoplastic elastomer or the hydrogenated carboxylic acid-modified thermoplastic elastomer constituting the adhesive composition and the crosslinking agent is not particularly limited, and depends on the desired adhesive strength of the pressure-sensitive adhesive. What is necessary is just to set suitably, For example, the range shall be 100: 1-100: 50, Preferably it is 100: 1-100: 25, More preferably, it is 100: 2-100: 10.

  The blending ratio of the pressure-sensitive adhesive composition and the adhesive composition constituting the pressure-sensitive adhesive layer is appropriately determined in consideration of the desired adhesive strength. Usually, the mass ratio of the solid component is 100: 0-5. : 95, preferably 100: 0 to 25:75, and practically 90:10 to 60:40. As the proportion of the pressure-sensitive adhesive composition increases, the generation of tunnels decreases, and as the adhesive composition increases, the adhesive strength increases. Additives such as UV absorbers, anti-static agents, dyes, antioxidants, and anti-aging agents can be added to the above-mentioned pressure-sensitive adhesives as necessary. Arbitrary additives can be added as long as they are not impaired.

In addition to the main components described above, additives such as antistatic agents can be added to the adhesive component. Examples of the antistatic agent include Elegan 264wax (trademark, manufactured by Nippon Oil & Fats Co., Ltd.) which is a cationic antistatic agent. The amount of the antistatic agent is usually based on the mass of the adhesive. 0.1-3.6 mass%, Preferably it is 0.6-1.8 mass%. By setting the amount within such a range, the occurrence of so-called “Yuzuhada” can be satisfactorily prevented.

The above adhesive composition, adhesive composition, and other optional additives are usually dissolved in an organic solvent that can be dissolved in common, for example, toluene to form an adhesive solution, and the surface of the base material layer. And then dried to obtain a pressure-sensitive adhesive layer. Although the usage-amount of the organic solvent used for said melt | dissolution is not specifically limited, Usually, 200-400 mass normally with respect to 100 mass parts of solid content total of said adhesive composition and adhesive composition. Parts, preferably 250 to 350 parts by mass.

  The application method of the above-mentioned pressure-sensitive adhesive solution may be a known method. Specific examples include a roller coating method, a brush coating method, a spray coating method, a dip coating method, a die coater, a bar coater, a knife coater, or An application method using a Mayer bar or the like can be mentioned. Further, the thickness of the pressure-sensitive adhesive layer (in the case of comprising two or more layers, the total thickness) is usually 10 to 500 μm, preferably 20 to 100 μm, and practically 20 to 50 μm. The drying conditions after coating are usually 0.5 to 2 minutes in hot air at 80 to 150 ° C, and preferably 40 seconds to 1.5 minutes in hot air at 100 to 130 ° C.

  In addition, when applying the above-mentioned pressure-sensitive adhesive solution to form a pressure-sensitive adhesive layer, an anchor layer is provided on the surface of the base material layer in advance in order to enhance the adhesiveness between the pressure-sensitive adhesive layer and the base material layer. Can do. As the anchor agent component constituting the anchor layer, the same adhesive composition as that used in combination with the pressure-sensitive adhesive layer can be employed. An anchor layer using such an adhesive composition is formed by dissolving the above-mentioned adhesive composition in an organic solvent such as toluene to form an anchor agent solution, coating the surface of the base material layer, and drying. The density | concentration of the anchor agent component in said anchor agent solution is 20-40 mass% normally, Preferably it is 25-35 mass%. It is preferable to add an antistatic agent to this anchor agent solution as in the case of the pressure-sensitive adhesive layer.

The coating amount of the anchor agent is usually 1 to 50 μm, preferably 1 to 15 μm, more preferably 2 to 5 μm as the thickness after drying. The drying conditions after coating are usually 80 for the anchor layer. It is 20 to 60 seconds in a warm air of ˜150 ° C., preferably 30 to 50 seconds in a warm air of 100 to 130 ° C. The coating method is not particularly limited, and can be based on the pressure-sensitive adhesive solution coating method.

  The surface of the pressure-sensitive adhesive layer of the inspection base paper having the pressure-sensitive adhesive layer formed as described above is released for the necessity during the manufacturing process, protection of the pressure-sensitive adhesive layer at the stage before practical use, etc. Layers can be stacked. Examples of such a release layer include a polyethylene terephthalate film and a polyolefin film whose surfaces are silicone-treated, but are not limited thereto. For example, when the adhesive force of the pressure-sensitive adhesive layer is particularly weak, a surface such as a silicone treatment is used. An untreated polyethylene terephthalate film or polyolefin film can also be used. In addition, in said manufacturing process, when mix | blending an adhesive composition with an adhesive layer and when providing an anchor layer, in order to accelerate | stimulate reaction of the said adhesive composition component, it is preferable to heat-process. The heat treatment condition is, for example, about 45 ° C. × 7 days to 80 ° C. × 2 days.

Below, the inspection method of the optical film by the test | inspection base paper which is the 2nd summary of this invention is demonstrated.
When the release layer is laminated, the inspection base paper of the present invention obtained as described above is peeled off to expose the adhesive surface of the adhesive layer, and this adhesive surface is used for optical inspection. By sticking to the back surface of the film, the presence / absence and uniformity of the coating layer of the optical film can be clearly evaluated. As a specific method, for example, the optical film to be inspected is placed so that the back surface side faces upward, the inspection base paper is positioned so as to be above the optical film, and one end of the optical film is positioned. The test piece is formed by laminating the entire surface in order from the state in which the pressure-sensitive adhesive layer is bonded to the optical film surface and the other end is lifted, and the test film is turned upside down to apply the optical film coating layer for inspection. The appearance of the interference fringe pattern generated on the coating layer on the surface is evaluated from the side.

During the bonding, it is preferable to taken not caught bubbles between the inspection base paper and by bonding an optical film for each inspection while pressing more from above manual rotation rollers, If the optical film to be inspected is floating in the air in the middle of the process, or the coating layer is sticky and the back side cannot be placed upward, the surface is supported from the coating layer side by a releasable plate. The base paper for inspection can be directly attached to the back surface of the optical film through the adhesive layer.

The determination method in the above inspection method generally has a relatively clear streak interference fringe with a narrow interval between the stripes in a portion where the thickness of the coating layer changes abruptly, such as a boundary region between the coating portion and the coating portion. When there are large and small coating spots on the coated surface, there is a difference between the narrow and wide intervals, but ring-shaped interference fringes occur, and no interference fringes occur on the non-coated surface. Depending on how the interference fringes appear, the presence / absence of the coating layer and the homogeneous state of the coating layer can be clearly determined. The inspection base paper of the present invention can clearly display how the interference fringes appear.

EXAMPLES The present invention will be specifically described below with reference to examples, but the examples shown below are not intended to limit the scope of the present invention. In this example, the test base paper was evaluated according to the following method.

(Rework and easy peelability)
After the release sheet of the base paper for inspection is peeled off, a 188 μm thick polyethylene terephthalate film (Lumirror 188T60, manufactured by Toray Industries, Inc.) as an adherend is left on the surface of the pressure-sensitive adhesive layer. In this way, crimping was performed. From this laminate, a strip-shaped test piece having a width of 25 mm was collected according to the adhesion test method of JIS Z 0237, and the test piece obtained by leaving it at 30 ° C. for 30 minutes was used for AUTOGRAPH AGS-50D manufactured by Shimadzu Corporation. Is used to grasp the layer of the base paper for inspection, and peel off each layer at a peeling rate of 300 mm by a peeling angle method of 180 degrees to measure the adhesive strength between the adhesive layer and Lumirror 188T60 as the adherend. And the average value of the measured value of each three test pieces was made into easy peelability.

(Rework and / or adherend contamination)
Further, the state of the adhesive remaining on the peeled surface on the Lumirror 188T60 side after peeling and the presence or absence of haze (gently) due to the adhesive are visually observed. The case where it was recognized was evaluated as Δ, and the case where an adhesive residue was clearly observed was evaluated as ×.

(Air release)
Thickness where one tip side in the length direction of the pressure-sensitive adhesive layer surface exposed by peeling off the release film of the test piece cut into a dimension of 200 mm in length and 20 mm in width from the inspection base paper was placed horizontally. Only the tip side portion was joined to the surface of Lumirror 188T60 having a thickness of 188 μm, and the other end was picked up with the fingertip and lifted to a position 150 mm above the Lumirror film, then released from the fingertip and overlaid on the entire surface. Then, the presence of tunnels and bubbles due to air entrainment was observed between the inspection base paper and the Lumirror film when the entire surface was pasted. The case where it was able to be removed by moving it was marked with ◯, and the case where tunnels and bubbles remained and could not be removed was marked with ×.

(Coating spot discrimination)
In the above inspection method, when the pattern of interference fringes on the side edge of the application part, in the application surface, and in the application spot intentionally generated in the application surface can be easily recognized without gazing, The case where it was clearly visible with a little gaze was indicated as ◯, the case where it was overlooked unless it was closely watched, and the case where it was not possible to judge due to incomplete adhesion of the inspection base paper. In addition, it was set as "-" when not determining.

(Optical density)
Measurement was performed using a TD-904 Macbeth densitometer (manufactured by Sakata Inx Corporation).
(Surface reflectance)
It measured using the MSC-P type multi-light spectrophotometer (made by Suga Test Instruments Co., Ltd.), and represented by the value in wavelength 550nm.

(Preparation of coated film as an alternative to optical film for inspection)
As an alternative to the optical film having a coating layer on the film, the following coated film was prepared.
A 75 μm-thick polyethylene terephthalate film (Lumirror) obtained by cutting a polyester resin (Byron 200, manufactured by Toyobo Co., Ltd.) solution (thickness diluted to 10% by mass with a mixed solvent of methyl ethyl ketone 50: toluene 50) into A4 size 75T60 (manufactured by Toray Industries, Inc.) was applied to the surface using a Mayer bar so that the thickness after drying was about 0.5 μm, and dried in hot air at 100 ° C. to obtain a film for inspection. Some of the coating portion of the object to be inspected for the film, a coating lutea intentionally formed dropped one drop a mixed solvent of the above from the dropper, further using a needle tip as representative of abrasion to other application portion It provided with a scratch single muscle.

[Example 1]
(Base layer of base paper for inspection)
30 parts by mass of a carbon black fine particle-containing resin liquid (VMD-795 black, manufactured by Dainichi Seika Co., Ltd.) and 3.0 parts by mass of an isocyanate curing agent (VMD curing agent, manufactured by Dainichi Seika Co., Ltd.) 6.2 parts by mass of a 50/50 mixed solvent was added and stirred well to prepare a carbon black fine particle-containing paint, and this paint was coated with a biaxially stretched polyethylene terephthalate film (Lumirror 75T60) having a thickness of 70 μm using a gravure roll. , Manufactured by Toray Industries, Inc.) so that the thickness after drying was 5 μm, and dried in hot air at 100 ° C. for 1 minute to obtain a black film for a substrate layer having a black surface. About the obtained black film for base materials layers, the optical density D and the surface reflectance were measured. The optical density was 4.76, and the surface reflectance (wavelength 550 μm) was 5.01%.

(Adhesive solution)
As an adhesive solution, as an adhesive component, 13.6 parts by mass of SEBS elastomer having a mass average molecular weight of 250,000, naphthenic oil as a plasticizer (flash point 220 ° C., pour point −25 ° C., specific gravity 0.8387, carbon 56.4), 6.86 parts by weight of maleic acid-modified SEBS and 1.14 parts by weight of coronate HL (the pressure-sensitive adhesive composition: the ratio as the adhesive composition is 80:20) Was mixed with 270 parts by mass of toluene, and stirred and dissolved well to obtain an adhesive solution.

This pressure-sensitive adhesive solution is applied to the surface of the above-mentioned black film as a base material layer containing carbon black fine particles so that the thickness after drying is 35 μm, and is heated and dried in hot air at 100 ° C. for 1 minute. After forming the pressure-sensitive adhesive layer, a release sheet (a 25 μm thick polyethylene terephthalate film whose surface is silicone-treated) is laminated face-to-face with a release sheet as a release layer. Got.
Using the obtained inspection base paper, the above-described evaluation method was used to evaluate the reworkability (adhesion strength and adherend contamination), air release property, and smear discrimination of the above-mentioned film for inspection. The results are shown in Table 1 together with the main production conditions of the inspection base paper.

[Example 2]
In Example 1, a 75 μm thick black inorganic fine particle kneaded type film (Lumirror 75X30 type, manufactured by Toray Industries, Inc.) was used instead of the black film coated with the carbon black fine particle-containing coating. Otherwise, the total light transmittance and the surface reflectance were measured for this film in the same manner as in Example 1. The optical density was 4.26, and the surface reflectance (wavelength 550 μm) was 8.37%. Next, in the same manner as in Example 1, an adhesive layer was laminated and a release layer was laminated to obtain an inspection base paper. Using the obtained inspection base paper, the reworkability (adhesion strength and adherend contamination), air release property, and smear discrimination property of the above-mentioned film for inspection were evaluated in the same manner as in Example 1. The results are shown in Table 1 together with the main production conditions of the inspection base paper.

[Comparative Example 1]
In Example 1, carbon-coated paper without an adhesive layer was used as an inspection base paper, and the carbon-coated paper was superimposed on the back surface of the film to be inspected to evaluate smearing discrimination. The results are shown in Table 1 together with the main production conditions of the inspection base paper.

[Comparative Example 2]
(Preparation of acrylic adhesive)
95.5 parts by mass of 2-ethylhexyl acrylate as a main component monomer, 2.5 parts by mass of 2-hydroxyethyl methacrylate, 1.0 part by mass of N-methylolacrylamide, 1.0 part by mass of acrylic acid as additive monomers In addition, 0.07 parts by mass of Kayaester O (manufactured by Kayaku Akzo Co., Ltd.) and 0.01 parts by mass of thiocalcol 20 (produced by Kao Co., Ltd.) as a chain transfer agent with respect to 100 parts by mass of the monomer component as a polymerization initiation catalyst. In addition, acrylic copolymer containing about 40% by mass of solid content after heating and refluxing with stirring in a nitrogen-substituted environment together with 150 parts by mass of ethyl acetate and allowing to react for 10 hours, after stopping heating and cooling with stirring. A solution of the composition was obtained. To the resulting acrylic copolymer composition solution (about 250 parts by mass), 3.2 parts by mass of an isocyanate-based crosslinking agent, Coronate HL (product of Nippon Polyurethane Industry Co., Ltd.), was added and stirred well. An agent was obtained.

An inspection base paper was prepared in the same manner as in Example 1 except that this adhesive was used in place of the adhesive in Example 1, and reworkability (adhesion strength and adherend) was further evaluated by the above evaluation method. Contamination), air bleedability, and smear discrimination were evaluated, and the results are shown in Table 1 together with the main production conditions of the test base paper.

The inspection base paper of the present invention is adhered and adhered to the back surface of the optical film to be inspected without producing a non-adhesive portion such as a tunnel and air bubbles that entrain air at the interface through the adhesive layer of the base paper. In the unlikely event that a tunnel-like non-adhered part occurs, it can be moved to the end of the optical film for inspection by pressing the part, or disappear, or on the back of the optical film for inspection Since the base paper can be peeled and pasted again without any adhesive residue, and it can be stuck and stuck together so as not to contain tunnels or bubbles, a preferable test body is formed, so the optical function of the optical film for inspection The presence / absence and uniformity of the coating layer, which is a layer, can be clearly distinguished, and its industrial effect is great.

Claims (7)

The base material layer is substantially opaque and has a surface reflectance of 10% or less. The main component is a thermoplastic elastomer and a plasticizer, which are composed of block segments composed of styrene monomer blocks and rubber monomer blocks. An optical film inspection base paper comprising an adhesive layer made of an adhesive composition. Test base paper of claim 1, further release sheet on the surface of the adhesive layer, characterized in that formed by laminating. Test base paper according to claim 1 or 2, characterized in that said plasticizer agent is a naphthenic oil and / or paraffin oil. The PSA composition, one further one of claims 1 to adhesive compositions composed mainly of a carboxylic acid-modified thermoplastic elastomer and the crosslinking agent is characterized by comprising been blended to 3 Inspection base paper as described in 1. Test base paper according to any one of claims 1 to 4, wherein the surface color of the base layer is black. Test base paper according to any one of claims 1 to 5, characterized in that the surface of the substrate layer is a coating layer mainly composed of carbon black particles. The inspection base paper according to any one of claims 1 to 6 is affixed to the back surface of the optical film, and the presence and uniformity of the optical film coating layer is determined by interference fringes appearing on the coating layer side. A method for inspecting an optical film.