JP6493733B2 - Method for producing protective film - Google Patents

Description

  The present invention relates to a method for manufacturing a protective film, a protective film, and a display.

Conventionally, in order to protect touch panel displays such as smartphones and tablet terminals from scratches, a transparent resin protective film has been attached to a liquid crystal display or an organic EL display.
Such a protective film is generally formed, for example, by cutting a sheet-like film material by laser processing to cut out the outer shape. Further, as a method of cutting a resin film or plate material, there is a case where cutting by an end mill is performed (for example, Patent Documents 1 to 3).

JP 2010-064203 A JP 2012-157914 A Japanese Patent No. 2912363

  When the film material is cut by laser processing, the peripheral edge of the protective film, which is a cut surface, is almost perpendicular to the surface direction. Since such a protective film has a sharp peripheral edge, when used as a protective film for a touch panel, there is a problem that a finger is caught on the peripheral part and the operability in the vicinity of the peripheral part is deteriorated.

  Further, when the film material is cut by cutting, chamfering can be performed together with the cutting. Therefore, it is possible to suppress finger catching at the peripheral portion and improve operability in the vicinity of the peripheral portion. However, when cutting is performed, chipping (small chipping) may occur on the cut surface. Since the film material is made of resin, the plastic deformation resistance is smaller than that of metal. For this reason, when cutting is performed, plastic deformation occurs in the vicinity thereof, and chipping tends to occur on the surface. When chipping occurs at the peripheral edge of the protective film, which is a cut surface, there is a problem that when the film is bent, the chipping becomes a starting point of cracking of the film and the film is easily broken.

  This invention is made | formed in view of the situation mentioned above, Comprising: A chamfering is given to a peripheral part and it aims at provision of the protective film which is hard to produce the crack by chipping.

In order to solve this problem, a method for producing a protective film according to an embodiment of the present invention is a method for producing a protective film to be attached to a display, and includes a pre-process for preparing a film material before cutting, A cutting step of cutting the film material, and the cutting step sends a taper blade end mill along the cutting line of the film material to form a V-shaped groove in the film material; , seen containing a second step of cutting the film material is irradiated along the laser beam to the cut line of the film material, wherein the cutting step, after the first step, the second step Do.

The film material has a main layer, and the main layer is preferably made of a photocurable resin, a thermosetting resin, or a thermoplastic resin.

  Further, in the manufacturing method of the protective film, in the previous step, a protective film is laminated as a part of the film material, and in the second step of the cutting step, the side opposite to the side irradiated with the laser beam You may cut | disconnect the said protective film located in the depth to the half cut.

  Moreover, the manufacturing method of said protective film WHEREIN: 1 mm or more and 5 mm or less may be sufficient as the width | variety of the said groove | channel in the said 1st process of the said cutting process.

  Further, in the manufacturing method of the protective film, in the second step of the cutting step, the spot diameter of the laser beam is 50% or less with respect to the width of the groove in the first step. There may be.

  The protective film which concerns on one Embodiment of this invention is a protective film affixed on a display, Comprising: The back surface located in the display side, the main surface located in the opposite side to a display, The said protective film extended in thickness direction A peripheral portion constituting the outer shape of the first peripheral surface, and the peripheral portion is formed between a first surface formed in a region having a certain thickness from the main surface side, and between the first surface and the back surface. And a second surface formed in the region, wherein the first surface has a smaller inclination with respect to the main surface than the second surface.

  Moreover, as for the manufacturing method of said protective film, the said 1st surface may have the inclination of 10 degrees or more and 60 degrees or less with respect to the said main surface.

  Moreover, as for the manufacturing method of said protective film, the said 2nd surface may have the inclination of 65 to 90 degree with respect to the said main surface.

  Moreover, as for the manufacturing method of said protective film, the said 1st surface may be provided in the area | region of 10% or more and 85% or less of the whole thickness.

  Moreover, the said protective film is affixed on the display which concerns on one Embodiment of this invention.

  ADVANTAGE OF THE INVENTION According to this invention, while protecting the operability of a peripheral part by giving a chamfer to a peripheral part, the protective film which a crack starting from a chipping does not produce easily can be provided.

It is sectional drawing which shows the laminated structure of the film material used for the manufacturing method of the protective film of embodiment. It is a top view which shows the cutting line set in the manufacturing method of the protective film of embodiment. It is a schematic diagram which shows the 1st process in the manufacturing method of the protective film of embodiment. It is a schematic diagram which shows the 2nd process in the manufacturing method of the protective film of embodiment. It is sectional drawing of the cutting separation part of two adjacent protective films in the manufacturing method of the protective film of embodiment. It is a top view of the protective film of embodiment, and shows the state stuck on the display.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In addition, in the drawings used in the following description, in order to make the features easy to understand, there are cases where the portions that become the features are enlarged for the sake of convenience, and the dimensional ratios of the respective components are not always the same as the actual ones. Absent.

FIG. 1 is a cross-sectional view showing a laminated structure of a film material 1 used for manufacturing a protective film 100 (see FIG. 6) of this embodiment.
The manufacturing process of the protective film 100 includes a preprocess for preparing the film material 1 before cutting and a cutting process for cutting the film material 1. In the present specification, the protective film 100 refers to a film obtained by cutting out a specific shape from the film material 1 and removing an unnecessary layer when affixing to a display.

  As shown in FIG. 1, the film material 1 of this embodiment has a seven-layer structure. The film material 1 includes a main body portion 20 having a five-layer structure and a pair of protective films 6A and 6B that are disposed so as to sandwich both sides of the main body portion 20 and protect the main body portion 20 from scratches in the manufacturing process. The protective films 6 </ b> A and 6 </ b> B are provided for the purpose of preventing the main body 20 from being damaged in the cutting process of cutting the film material 1. The protective films 6A and 6B are peeled off after the cutting process is completed.

  The main body 20 has a lower surface 20b located on the side to be attached to the display, and an upper surface 20a located on the opposite side. The main body 20 includes a hard coat layer 3, a main layer 2, an adhesive layer 4, and a separator layer 5 in order from the upper surface 20 a side.

The hard coat layer 3 is a layer made of a resin that is harder than other layers. The hard coat layer 3 is formed on the outermost surface of the main body 20 for the purpose of suppressing the occurrence of scratches on other layers disposed below the hard coat layer 3.
The main layer 2 is a layer mainly constituting the protective film 100. The main layer 2 will be described in more detail later.
The pressure-sensitive adhesive layer 4 is a layer provided with a pressure-sensitive adhesive for attaching the protective film 100 to the display.
The separator layer 5 is a layer that is detachably attached to the pressure-sensitive adhesive layer 4. The separator layer 5 can be easily peeled off, and by peeling the separator layer 5, the pressure-sensitive adhesive layer 4 can be exposed and the protective film 100 can be attached to the display.

The main layer 2 is exemplified by a photocurable resin composition, but is not limited thereto as long as it can be used as a film material for a touch panel.
As the photocurable resin composition constituting the main layer 2, one that undergoes a curing reaction (polymerization reaction) by active energy rays such as light (ultraviolet rays and visible light) and an electron beam can be used. Further, the photocurable resin composition is preferably obtained by blending a polymerizable resin component with a photopolymerizable initiator. In particular, the photocurable resin composition is preferably a compound having a plurality of photopolymerizable carbon-carbon double bonds.

  The main layer 2 can be formed by sandwiching a liquid (uncured) photocurable resin composition between a pair of substrate films and processing it into a strip shape, and then irradiating it with ultraviolet rays to cure it. A pair of base film used here is a film made of a light transmissive resin capable of transmitting ultraviolet rays. The base film may have a function of transferring the hard coat layer to the main layer 2.

  Examples of the photocurable resin composition include (1) polyvalent allyl ester resin, (2) polyvalent vinyl ester resin, (3) polyfunctional urethane (meth) acrylate resin, and (4) cage-type siloxane- (meta ) Acrylate resin composition.

(1) The polyvalent allyl ester resin is a composition containing a polyvalent allyl ester compound and a photopolymerization initiator. The polyvalent allyl ester compound is produced by a transesterification reaction between an allyl ester monomer of a polyvalent carboxylic acid and a C 2-20 polyhydric alcohol having 2 to 6 hydroxyl groups.
Specific examples of the allyl ester monomer of polyvalent carboxylic acid include diallyl phthalate, diallyl isophthalate, diallyl terephthalate, diallyl 2,6-naphthalenedicarboxylate, diallyl 1,2-cyclohexanedicarboxylate, 1,3-cyclohexanedicarboxylic acid Examples include diallyl acid, diallyl 1,4-cyclohexanedicarboxylate, diallyl endomethylenetetrahydrophthalate, diallyl methyltetrahydrophthalate, diallyl adipate, diallyl succinate, diallyl maleate, and the like. These allyl ester monomers can be used in combination of two or more as required, and are not limited to the specific examples described above.

Among specific examples of the polyhydric alcohol having 2 to 20 carbon atoms, the divalent alcohol includes ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neo Pentyl glycol, hexamethylene glycol, 1,4-cyclohexanedimethanol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, diethylene glycol, dipropylene glycol, triethylene glycol, polyethylene glycol, Examples include bisphenol-A ethylene oxide adduct, bisphenol-A propylene oxide adduct, 2,2- [4- (2-hydroxyethoxy) -3,5-dibromophenyl] propane, and the like.
Specific examples of the trihydric or higher polyhydric alcohol include glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, dipentalysitol and the like. These polyhydric alcohols may be a mixture of two or more. Moreover, it is not limited to the above-mentioned specific example.

Furthermore, the polyvalent allyl ester compound is radically polymerizable and can be polymerized by heat, ultraviolet rays, electron beams or the like. It can also be copolymerized with other radically polymerizable compounds.
The radical polymerizable compound to be copolymerized with the polyvalent allyl ester compound is not particularly limited as long as it is a compound copolymerizable with the polyvalent allyl ester compound. Specific examples thereof include diallyl phthalate, diallyl isophthalate, diallyl terephthalate, allyl benzoate, allyl α-naphthoate, allyl β-naphthoate, allyl 2-phenylbenzoate, allyl 3-phenylbenzoate, 4-phenylbenzoic acid. Allyl, allyl o-chlorobenzoate, allyl m-chlorobenzoate, allyl p-chlorobenzoate, allyl o-bromobenzoate, allyl m-bromobenzoate, allyl p-bromobenzoate, 2,6-dichlorobenzoate Allyl acid, allyl 2,4-dichlorobenzoate, allyl 2,4,6-tribromobenzoate, diallyl 1,4-cyclohexanedicarboxylate, diallyl 1,3-cyclohexanedicarboxylate, diallyl 1,2-cyclohexanedicarboxylate, 1-cyclohexene-1,2-dicarboxylic acid di Allyl, 3-methyl-1,2-cyclohexanedicarboxylic acid diallyl, 4-methyl-1,2-cyclohexanedicarboxylic acid diallyl, endic acid diallyl, chlorendic acid diallyl, 3,6-methylene-1,2-cyclohexanedicarboxylic acid Allyl esters such as diallyl, triallyl trimelliate, tetraallyl pyromellitic acid, diallyl diphenate, diallyl succinate, diallyl adipate, dibenzyl malate, dibenzyl fumarate, diphenyl malate, diphenyl fumarate, dibutyl maleate Maleic acid diesters / fumaric acid diesters, such as rate, dibutyl fumarate, dimethoxyethyl fumarate, dimethoxyethyl fumarate, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate , I-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, phenyl (meth) acrylate, stearyl (meth) acrylate, lauryl (meth) acrylate, benzyl (meth) acrylate, isobornyl (Meth) acrylate, trimethylolpropane tri (meth) acrylate, ethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9- Nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene diglycol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra ( ) Acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, tri (Meth) acrylic esters such as cyclodecanedimethanol di (meth) acrylate, dicyclopentenyl (meth) acrylate, ethoxylated cyclohexanedimethanol dimethacrylate, adamantyl (meth) acrylate; styrene, α-methylstyrene, methoxystyrene , Aromatic vinyl compounds such as divinylbenzene; aliphatic carboxyl such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl stearate, vinyl caproate Vinyl ester; cycloaliphatic carboxylic acid vinyl ester and other alicyclic vinyl esters; benzoic acid vinyl ester and t-butyl benzoic acid vinyl ester and other aromatic vinyl esters, diallyl carbonate, diethylene glycol bisallyl carbonate, trade name CR manufactured by PPG -39 Allyl carbonate compounds such as polyethylene glycol bis (allyl) carbonate resin represented by 39, allyl (meth) acrylate having a different polymerizable double bond in the molecule, vinyl (meth) acrylate and maleic acid Compounds such as diallyl, nitrogen-containing polyfunctional allyl compounds such as triallyl isocyanurate and triallyl cyanurate, unsaturated polyester resin, vinyl ester resin, urethane acrylate, epoxy acrylate and other oligoacrylates, etc. And the like.

  However, these radically polymerizable compounds are merely examples and are not limited to the above. These radically polymerizable compounds may be used in combination of two or more in order to obtain the desired physical properties.

  (2) As polyvalent vinyl ester resin, what substituted the allyl group of the said polyvalent allyl ester by the vinyl group is mentioned.

  (3) The polyfunctional urethane (meth) acrylate resin is obtained by reacting a polyisocyanate compound and a hydroxyl group-containing (meth) acrylate compound using a catalyst such as dibutyltin dilaurate as necessary. Can be mentioned. Examples of polyisocyanate compounds include isophorone diisocyanate, tricyclodecane diisocyanate, norbornene diisocyanate, 1,3-diisocyanatocyclohexane, 1,4-diisocyanatocyclohexane, hydrogenated xylylene diisocyanate, and hydrogenated diphenylmethane diisocyanate. Examples include isocyanate compounds. Specific examples of the hydroxyl group-containing (meth) acrylate compound include, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3- ( Examples include meth) acryloyloxypropyl (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol tetra (meth) acrylate, and dipentaerythritol tri (meth) acrylate.

  (4) Examples of the cage siloxane- (meth) acrylate resin composition include the resin composition described in JP 2010-195986 A.

  Moreover, as resin which can be used for the main layer 2, it is applicable also to thermoplastic resins, such as thermosetting resins, such as an epoxy resin, PMMA, a polycarbonate other than the above-mentioned photocurable resin composition.

<Pre-process>
A method for manufacturing the protective film 100 will be described. First, the pre-process for preparing the film material 1 will be described.
The main body 20 can be formed by laminating other layers on the main layer 2. As described above, the main layer 2 is formed by sandwiching a liquid (uncured) photo-curable resin composition between a pair of base films and processing them into a strip shape, and then curing by irradiating with ultraviolet rays to remove the base film. Can be formed.
After forming the main layer 2, the hard coat layer 3 is formed on one surface of the main layer 2, the pressure-sensitive adhesive layer 4 is formed on the other surface, and the separator layer 5 is disposed on the pressure-sensitive adhesive layer 4. Thereby, the main-body part 20 is formed.
Next, the protective film 6 </ b> A, 6 </ b> B is laminated on both the front and back surfaces of the main body 20 to form the film material 1. The main body 20 and the protective films 6A and 6B are preferably bonded in a peelable manner.
By passing through these steps, the pre-process for preparing the film material 1 is completed.

<Cutting process>
Next, the cutting process of the film material 1 is performed.
First, as shown in FIG. 2, the cutting line C is set to the film material 1 sandwiched between the pair of protective films 6A and 6B. The cutting line C constitutes the outer shape of the protective film 100 cut out from the film material 1. The cutting line C constitutes a boundary between the unnecessary portion 101 located between the adjacent protective films 100 and the protective film 100, and a boundary of the holes 25 in the protective film 100.
The cutting process includes a first process and a second process described below. The cutting step is a step of cutting by running the end mill 10 or the laser beam L along the cutting line C in the first step and the second step, respectively.

<First step>
Next, the first step of feeding and cutting the end mill 10 rotating along the cutting line C along the cutting line C is performed.
As shown in FIG. 3, the end mill 10 includes a shaft portion 11 that is connected to a rotating shaft of a machining apparatus such as a milling machine and extends linearly, and a taper portion 12 that is positioned on the tip side of the shaft portion 11. The taper portion 12 is provided with a taper blade 12a. A flat portion 12 b is provided at the tip of the tapered portion 12. The taper blade 12a is provided in a region having a length h12 from the tip of the end mill 10. The taper blade 12a and the flat portion 12b form an angle α.
A blade is also formed on the flat portion 12 b of the end mill 10. Therefore, the flat portion 12b is not a flat shape but a portion where the object cut by the flat portion 12b is flat.

  As shown in FIG. 3, in the first step, the end mill 10 is cut from the surface 1 a side of the film material 1 by the tapered blade 12 a of the tapered portion 12. The end mill 10 cuts the film material 1 from the surface 1a by a depth h30. The depth h30 is a distance shallower than the height h12 of the tapered blade 12a of the end mill 10. That is, the end mill 10 performs cutting without inserting the linearly extending shaft portion 11 below the surface 1 a of the film material 1. Thereby, the 1st inclined surface (1st surface) 31 continuous with the surface 1a is formed in the film material 1 by a 1st process. The inclination angle of the first inclined surface 31 is derived from the inclination angle of the tapered blade 12a. Therefore, the first inclined surface 31 and the surface 1a of the film material 1 form an angle α.

Since the first inclined surface 31 is formed along the cutting line C, a V-shaped groove 30 is formed in the film material 1. The groove 30 has a symmetrical shape with respect to the center line J30 along the cutting line C as a reference line.
The groove 30 is formed with a width d30. The width d30 is preferably 1 mm or more and 5 mm or less. By setting the width d30 to 1 mm or more, the first inclined surface 31 in the protective film 100 is secured sufficiently large. Moreover, the 1st inclined surface 31 becomes large too much in the protective film 100 because the width | variety d30 shall be 5 mm or less, and the visibility of the display visually recognized through the protective film 100 does not deteriorate. For the same reason, the width d30 is more preferably 2 mm or more and 4 mm or less.
The width d30 of the groove 30 is determined by the cutting depth of the end mill 10 with respect to the film material 1 and the angle α of the taper blade 12a. Therefore, the width d30 can be controlled by adjusting the cutting depth according to the angle α of the tapered blade 12a.

Further, since the flat portion 12 b is provided at the tip of the end mill 10, a flat bottom portion 32 is formed in the groove 30. The width d32 of the bottom 32 is substantially the same as the diameter of the flat portion 12b at the tip of the end mill 10.
Note that the end portion of the end mill 10 may not be provided with the flat portion 12b. That is, the end mill 10 may have a sharp shape in which the tapered blade 12a is formed up to the tip. In this case, the flat bottom portion 32 is not formed in the groove 30.

  Next, as shown in FIG. 4, along the cutting line C, a laser beam L is irradiated from the surface 1 a of the film material 1 to perform a second step of cutting the film material 1. In the cutting line C, the groove 30 formed in the first step is formed, and the laser light L is shifted from the center line J30 of the groove 30 to the center line J40 deviated to the protective film side (left side in FIG. 4). Irradiated along. This is because the width of the laser beam L is considerably smaller than the width of the groove 30. The film material 1 on the right side of FIG. If the width of the groove 30 is narrow, the laser beam L may be irradiated along the center line of the groove 30. In this case, since the film material 1 on the right side of FIG. 4 is not used as the unnecessary portion 101 and can be used as a protective film, loss of raw materials can be reduced.

  By irradiating the laser beam L, the film material 1 is formed with a groove-shaped cut portion 40 which is melted and cut by a depth h40 from the surface 1a side in the depth direction. The cutting part 40 is formed so as to penetrate the protective film 6A on the surface 1a side of the film material 1 and the main body part 20 and to half-cut the lower protective film 6B. The depth h40 of the cutting part 40 can be controlled by appropriately adjusting the output (energy density) of the laser light L and the irradiation time.

  The cutting part 40 cut by the laser beam L has a shape with a wide opening on the surface 1a side. The laser beam L is irradiated from the surface 1a side of the film material 1, and in order to melt the film material 1 gradually from the surface 1a side, the region closer to the surface 1a is affected by heat longer. Thereby, in the cutting | disconnection by the laser beam L, the 2nd inclined surface (2nd surface) 41 which spreads toward opening slightly is formed.

The second inclined surface 41 and the surface 1a of the film material 1 form an angle β. The inclination angle of the second inclined surface 41 depends on the output (energy density) of the laser light L. When the output of the laser beam L is increased, the angle β increases and approaches 90 °.
Moreover, when the output of the laser beam L is lowered, it is necessary to lengthen the time (irradiation time) for cutting at a predetermined depth. As a result, the time during which the opening side is affected by heat becomes longer, the angle β becomes smaller, and the opening becomes wider.

The spot diameter ds of the laser beam L is larger than the width d32 of the bottom 32 of the groove 30. Thereby, the bottom portion 32 of the groove 30 is completely melted, and the second inclined surface 41 of the cutting portion 40 becomes a surface continuous with the first inclined surface 31.
The spot diameter ds of the laser beam L is 50% or less with respect to the width d30 of the groove 30 in the first step. Thereby, even after passing through the second step, the first inclined surface 31 of the groove 30 is not melted by the laser light L and remains in a sufficient size on both sides of the cutting portion 40. Become. More specifically, when the width d30 of the groove 30 is set to 1 mm or more, the first inclined surface 31 is set to 0.5 mm or more by setting the spot diameter ds of the laser light L to 50% or less of the width d30. It can be secured.

  The laser beam L is melted by heat to cut the film material 1. The influence of heat extends not only to the cutting part 40 but also to the surroundings. Chipping (small chipping) may occur on the first inclined surface 31 formed by the cutting by the end mill 10 in the first step. The heat at the time of cutting with the laser beam L slightly melts the film material 1 around the chipping, and the chipping is embedded and disappeared. The heat at the time of cutting by the laser beam L rounds off the acute notch formed at the innermost part of the chipping, making it difficult to make the chipping the starting point of the crack.

The cutting process is completed through the first process and the second process described above.
The first step and the second step may be performed in the reverse order. That is, the second process using the laser beam L may be performed first, and the first process using the end mill 10 may be performed later. In this case, the effect of embedding chipping or rounding the notch due to the influence of heat from the laser beam L is not achieved. For this reason, as described above, it is more preferable to perform the second step after the first step.

  Further, after the cutting process is completed, the protective films 6A and 6B are removed. Since the lower protective film 6B of the pair of protective films 6A and 6B is half-cut, a plurality of protective films 100 are mounted on the protective film 6B. Therefore, the plurality of protective films 100 are not dispersed, and the recovery operation can be facilitated by collecting the protective films 100 while removing the lower protective film 6B.

<Protective film>
FIG. 5 is a cross-sectional view of two adjacent protective films 100 cut and separated in the above-described manufacturing process. Although the separator layer 5 is laminated | stacked on the protective film 100 of FIG. 5, when using the protective film 100, the separator layer 5 is removed.
FIG. 6 is a plan view of the protective film 100 and shows a state of being attached to the display 60.

The protective film 100 has a back surface 100b which is a surface to be attached to the display 60, a main surface 100a located on the opposite side, and a peripheral edge portion 100c extending in the thickness direction. The peripheral edge portion 100c constitutes the outer shape of the protective film 100 (or the outer shape of the hole 25).
Moreover, the protective film 100 has the hard-coat layer 3, the main layer 2, and the adhesive layer 4 in an order from the main surface 100a side.

As shown in FIG. 5, the peripheral portion 100c includes a first inclined surface (first surface) 31 formed in a region having a certain thickness from the main surface 100a side, a first inclined surface 31, and a back surface 100b. 2nd inclined surface (2nd surface) 41 formed in the area | region between. The first inclined surface 31 is derived from the first step (end milling), and the second inclined surface 41 is derived from the second step (cutting with the laser beam L).
The angle α of the first inclined surface 31 with respect to the main surface 100a is smaller than the angle β of the second inclined surface 41 with respect to the main surface 100a.

The angle α of the first inclined surface 31 with respect to the main surface 100a is preferably 10 ° or more and 60 ° or less.
By setting the angle α to 10 ° or more, the angle formed by the main surface 100a and the first inclined surface 31 becomes gentle, and the finger is hardly caught at the peripheral edge portion 100c.
Moreover, by setting the angle α to 60 ° or less, the angle γ of the corner portion 39 between the first inclined surface 31 and the second inclined surface 41 becomes gentle, and the finger is hardly caught at the peripheral edge portion 100c.
For the same reason, the angle α is more preferably 15 ° or more and 45 ° or less.

The first inclined surface 31 is preferably provided in a region of 10% to 85% of the thickness D of the protective film 100. That is, the value of d1 is preferably 10 to 85% of the value of D.
By providing the 1st inclined surface 31 in the area | region of 10% or more of the thickness D of the protective film 100, the 1st inclined surface 31 can be ensured large enough and the effect as chamfering can be improved. That is, the protective film 100 is less likely to get a finger caught at the peripheral edge portion 100c.
Moreover, since the 1st inclined surface 31 is formed by the cutting process by the end mill 10, the chipping which may become a crack starting point may arise. Therefore, the 1st inclined surface 31 can be made small by making the 1st inclined surface 31 into the area | region of 85% or less of the thickness D of the protective film 100, and generation | occurrence | production of a crack can be suppressed.

The angle β of the second inclined surface 41 with respect to the main surface 100a is preferably 65 ° or more and 90 ° or less.
By setting the angle β to 65 ° or more, the length of the second inclined surface 41 along the surface direction of the protective film 100 can be shortened. That is, the 2nd inclined surface 41 in front view can be made small, and the visibility of the display 60 visually recognized through the protective film 100 does not deteriorate. Further, the angle β is preferably set to 75 ° or more for the same reason.

  The angle β of the second inclined surface 41 with respect to the main surface 100a is inevitably 90 ° or less when the laser beam L is irradiated from the surface 1a side of the film material 1 (see FIG. 4). Since the cutting process in the first step is performed from the surface 1a side of the film material 1, the irradiation of the laser light L from the surface 1a side of the film material 1 is performed in the second step from the same direction as the first step. Means to do. Therefore, the first step and the second step can be continuously performed on the same line by irradiating the laser beam L from the surface 1a side of the film material 1 and setting the angle β to 90 ° or less. The process can be simplified.

  The angle β of the second inclined surface 41 with respect to the main surface 100a is more preferably 85 ° or less. By setting the angle β to 85 ° or less, the angle γ formed by the corner portion 39 that is the boundary between the first inclined surface 31 and the second inclined surface 41 can be increased. Increasing the angle γ makes it difficult for the finger to get caught at the corner 39 between the first inclined surface 31 and the second inclined surface 41. Therefore, when this protective film 100 is affixed to the display 60, the operativity in the vicinity of the peripheral part 100c can be improved.

According to the protective film 100 of this embodiment, the 1st inclined surface 31 located in the main surface 100a side and the 2nd inclined surface 41 located in the back surface 100b side are formed in the peripheral part 100c.
The first inclined surface 31 is a surface cut by the taper blade 12a of the end mill 10, and has a sufficient inclination angle (angle α). Therefore, on the main surface 100a side, when the user carries his / her finger from the outer side of the peripheral part 100c toward the inner side, the finger is not easily caught by the peripheral part 100c. Thereby, the operativity of a touchscreen is not inhibited in the vicinity of the peripheral part 100c.

  Further, the protective film 100 has a second inclined surface 41 processed by the laser light L. In addition, the second inclined surface 41 is located on the outer side in plan view at the peripheral edge portion 100 c than the first inclined surface 31. The first inclined surface 31 may be chipped because it is formed by cutting. However, since the 2nd inclined surface 41 is located inside the 1st inclined surface 31, even when it is a case where the protective film 100 is bent, it is hard to apply stress to the 1st inclined surface 31. . Therefore, even when chipping is formed on the first inclined surface 31, the chipping is unlikely to become a starting point of a crack. That is, since the protective film 100 includes the second inclined surface 41, it is difficult for cracks to occur.

Although the embodiments of the present invention have been described above, the configurations and combinations thereof in the embodiments are examples, and the addition, omission, replacement, and others of the configurations are within the scope not departing from the gist of the present invention. Can be changed.
For example, the layer structure of the film material 1 is not limited to this. For example, the hard coat layer 3, the pressure-sensitive adhesive layer 4, and the separator layer 5 may be omitted. Similarly, the protective film 100 may be composed only of the main layer 2.

  EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated further in detail, this invention is not limited to these Examples.

<Preparation of sample>
First, the film material 1 shown in FIG. 1 is prepared. The film material 1 includes a main body 20, a protective film 6 </ b> A having a thickness of 43 μm and a protective film 6 </ b> B having a thickness of 150 μm, which are arranged so as to sandwich the main body 20. The main body 20 has a 6 μm hard coat layer 3, a main layer 2 of 200 μm to 300 μm (see Table 1), a 50 μm pressure-sensitive adhesive layer 4, and a 50 μm separator layer 5.

The film material 1 described above was cut.
Sample No. 1, no. No. 2, the first step (cutting by the end mill 10) and the second step (cutting by the laser beam L) were performed in this order and cut.
Sample No. 3 was prepared by performing only the second step.
Sample No. 4 was produced by performing only the first step.

  The first step was performed by rotating the end mill 10 at a rotational speed of 50000 rpm and feeding it at a feed rate of 500 mm / min. The end mill 10 used in the first step was appropriately selected so that the angle α in FIG. The diameter of the end mill used in Examples 1 and 2 is 3 mm, and the low end diameter at the tip is 2 mm. Moreover, the diameter of the end mill used in Example 4 was 3 mm, and there was no taper (the diameter of the low end portion of the tip was also 3 mm).

The second step was performed using a CO ₂ laser device (Laser Marker manufactured by Panasonic Corporation). The laser output was 40 W and the cutting speed was 2500 mm / min. Further, the irradiation time was appropriately selected so that the angle β in FIG.

<Evaluation>
The produced sample No. 1-No. Evaluation of the operativity of the peripheral part vicinity and a crack test were done with respect to 4 protective films.
As evaluation of the operativity of the peripheral part vicinity, the sensory evaluation by the 10 evaluators arbitrarily selected was performed. The evaluation score of each evaluator is tabulated and the results are shown in Table 1 in two stages of ◯ and ×.

The crack test was performed according to the following procedure.
First, φ2 mm and φ3 mm rod cylinders having sufficient lengths were prepared.
A plurality of each of the prepared samples was wound around a half-diameter cylinder of φ2 mm and a cylinder of φ3 mm half-turned, and it was confirmed whether or not a crack occurred.
When one of the five cracks was cracked, it was rated as x. When three or fewer cracks were observed, the mark was Δ, and when there was no crack, mark was marked as ◯.

  In Table 1, Sample No. 1-No. The structure of 4 protective films and an evaluation result are shown collectively.

As shown in Table 1, the sample No. which performed the 1st process and the 2nd process. 1, no. About 2, the operativity of the peripheral part 100c vicinity of a protective film and the evaluation result of the crack test became a favorable thing.
On the other hand, sample No. which performed only the 2nd process (cutting by laser beam L). The protective film 3 has poor operability in the vicinity of the peripheral edge portion 100c. This is sample no. Since the protective film 3 has only the second inclined surface 41 formed on the peripheral edge portion 100c and the first inclined surface 31 is not formed, the inclination angle is nearly perpendicular to 88 ° and the finger is caught. It is believed that there is.
In addition, sample No. 1 in which only the first step (cutting by the end mill 10) was performed. From the result of the crack test, it was found that the protective film No. 4 was prone to crack. This is sample no. In the protective film 4, only the first inclined surface 31 in which the peripheral portion 100c may be chipped is formed. Therefore, sample no. In the protective film No. 4, it is considered that the chipping of the first inclined surface 31 became the starting point of the crack. In addition, since only the first step is performed, the effect of heat at the time of cutting with the laser beam L is not added to the chipping, and the effect that the chipping is buried cannot be achieved. This is thought to be one of the reasons why it is likely to occur.

  As described above, it was confirmed that by performing the first step and the second step, the operability in the vicinity of the peripheral portion 100c was improved, and cracks starting from the peripheral portion 100c were less likely to occur. .

DESCRIPTION OF SYMBOLS 1 ... Film material, 1a ... Surface, 2 ... Main layer, 3 ... Hard coat layer, 4 ... Adhesive layer, 5 ... Separator layer, 6A, 6B ... Protective film, 10 ... End mill, 11 ... Shaft part, 12 ... Taper Part 12a ... taper blade 12b flat part 20 ... body part 25 ... hole 30 ... groove 31 ... first inclined surface (first surface) 32 ... bottom part 40 ... cutting part 41 ... Second inclined surface (second surface), 60 ... display, 100 ... protective film (piece), 100a ... main surface, 100b ... back surface, 100c ... peripheral edge, C ... cutting line, D ... thickness, L ... Laser light, d30, d32 ... width, ds ... spot diameter, h12 ... height, α, β, γ ... angle

Claims (5)

A method for producing a protective film to be attached to a display,
A pre-process for preparing a film material before cutting;
A cutting step of cutting the film material,
The cutting step includes
A first step of feeding a taper blade end mill along a cutting line of the film material to form a V-shaped groove in the film material;
A second step of irradiating along the laser beam to the cutting line of the film material cut the film material, only including,
The cutting step performs the second step after the first step.
A method for producing a protective film. The film material has a main layer,
The manufacturing method of the protective film of Claim 1 with which the said main layer consists of photocurable resin, a thermosetting resin, or a thermoplastic resin. In the previous step, a protective film is laminated as a part of the film material,
In the second step of the cutting step, the protective film located on the side opposite to the side irradiated with the laser light is cut to a depth of half-cut,
The manufacturing method of the protective film of Claim 1 or 2. In the first step of the cutting step, the width of the groove is 1 mm or more and 5 mm or less.
The manufacturing method of the protective film as described in any one of Claims 1-3. In the second step of the cutting step, the spot diameter of the laser light is 50% or less with respect to the width of the groove in the first step.
The manufacturing method of the protective film as described in any one of Claims 1-4 .

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