JP5945084B1 - Front panel manufacturing method - Google Patents

Abstract

The present invention relates to a method of manufacturing a front panel having a configuration in which a coating layer is laminated on the surface of a panel base material having a smooth peripheral portion around a display surface portion having a large number of irregularities on the surface. While maintaining the antiglare effect on the surface portion, it is also possible to prevent the generation of yuzu skin on the smooth surface. A base material injection molding step of forming the panel base material member 1 having a peripheral portion 2 around the display surface portion 1 by injection molding, and a transparent resin on the surfaces of the display surface portion 1 and the peripheral portion 2 In a method for manufacturing a front panel including a coating step of coating to form the coat layers 11 and 12, the average value Aav of the thickness of the coat layer 11 of the display surface portion 1 and the thickness of the coat layer 12 of the peripheral portion 2 A method for manufacturing a front panel is proposed in which a transparent resin is coated so that the average value Bav of Av is smaller than Aav <Bav.

Description

  The present invention relates to a method of manufacturing a front panel used for an operation panel of a car navigation system, an industrial machine, etc., in addition to a front panel of a smartphone, a tablet terminal, a portable game device or the like.

  Conventionally, glass materials have been used for base materials for front panels used as operation panels for car navigation and the like in addition to smartphones and tablet terminals. However, since glass materials are inferior in impact resistance, lightness, and the like, alternatives to synthetic resin materials have been proposed.

  For example, Patent Document 1 discloses a resin laminate in which a hard coat layer is laminated on a laminate obtained by coextruding a polycarbonate resin and an acrylic resin.

  Further, in Patent Document 2, an acrylic resin layer is formed by coextrusion molding at least on the surface of the polycarbonate resin layer to be touched as a laminated extruded resin plate for a touch panel that is hardly scratched and is relatively easy to manufacture. A laminated extruded resin plate for a touch panel, characterized by being laminated, is disclosed.

  Furthermore, as a touch panel display device using such a resin plate, a front panel device is disclosed in which a touch panel for touch input is arranged on the resin plate as described above (see, for example, Patent Document 3).

JP 2006-103169 A JP 2010-182263 A JP 2002-40243 A

  By the way, when the resin plate formed by extrusion molding as described above is used as an operation panel such as a smartphone or a car navigation system, secondary processing such as thermoforming or the like, usually secondary processing such as printing or punching is performed. There was a need to do. On the other hand, if this type of front panel can be formed by injection molding, the secondary processing steps such as thermoforming and drilling can be omitted, and a special shape such as an opening and a curved portion is provided. Even if it exists, it can manufacture easily.

For example, according to injection molding, in order to provide an anti-glare effect, fine irregularities are formed on the image display surface of the front panel, and the peripheral surface of the image display surface is smoothed to give a high-class feeling. It can also be formed as a surface.
However, in this way, in order to provide an anti-glare effect, when a fine unevenness is formed on the image display surface of the front panel, when a hard coat layer as in Patent Document 1 is laminated on the surface side, a folding angle is obtained. It has been found that the antiglare effect may be reduced. At this time, it has been found that if the thickness of the hard coat layer is reduced, the reduction of the antiglare effect can be suppressed, but the skin is likely to occur on the smooth surface.

  Accordingly, the present invention provides a front panel having a configuration in which a coating layer is laminated on the surface of a panel substrate having a surface portion having a peripheral portion made of a smooth surface around a display surface portion having a large number of irregularities. With respect to the method, the present invention proposes a new front panel manufacturing method capable of preventing the occurrence of the skin on the smooth surface while maintaining the antiglare effect on the display surface portion.

  The present invention relates to a base material injection molding in which a panel base material member having a base surface portion having a display surface portion having a large number of irregularities and a peripheral portion made of a smooth surface around the display surface portion is formed by injection molding. And a coating process for forming a coating layer by coating a transparent resin on the surfaces of the display surface portion and the peripheral portion of the panel base member, the coating layer for the display surface portion A method of manufacturing a front panel, characterized in that a transparent resin is coated so that the average value Aav of the thickness of the coating and the average value Bav of the thickness of the coating layer in the peripheral portion have a relationship of Aav <Bav To do.

According to the method for manufacturing a front panel proposed by the present invention, a panel substrate member having a substrate surface portion having a peripheral portion made of a smooth surface is produced by injection molding around a display surface portion having a large number of irregularities. Furthermore, a front panel can be manufactured by laminating a coat layer on the surfaces of the display surface portion and the peripheral portion, and further processing as necessary.
And at this time, by giving a difference between the thickness of the coat layer of the display surface portion and the thickness of the coat layer of the peripheral portion, by relatively increasing the thickness of the coat layer of the display surface portion having a large number of irregularities on the surface, While maintaining the anti-glare effect on the display surface portion, it is possible to prevent the occurrence of itchy skin in the surrounding portion. Therefore, the front panel obtained by the manufacturing method proposed by the present invention can be suitably used for, for example, a touch panel display for in-vehicle devices.

It is the figure which showed an example of the member for panel base materials used by an example of this invention, Comprising: (A) is the sectional drawing, (B) is the perspective view seen from the upper surface side. It is sectional drawing which showed an example of the front panel manufactured by an example of this invention.

  Next, the present invention will be described based on an embodiment. However, the present invention is not limited to the embodiment described below.

<This manufacturing method>
A method for manufacturing a front panel according to an example of an embodiment of the present invention (referred to as “the present manufacturing method”) includes: a base material injection molding process for injection molding a panel base material member; and a base material for the panel base material member And a coating step of forming a coat layer by coating a transparent resin on the surface portion, that is, the viewing-side surface portion.

The panel base member only needs to have the form of a panel base, and if necessary, an extra portion (also referred to as “remaining part”) is deleted to obtain a final form of the panel base. What is necessary is just to be able to form.
As long as the manufacturing method includes the base material injection molding process and the coating process, it may include other processes. For example, an annealing process, a printing process, a cutting process, and other processes described later can be inserted.

<Base material injection molding process>
In the substrate injection molding process, a panel substrate member is formed by injection molding.

(Materials for panel base materials)
The material for the panel substrate member may be a transparent thermoplastic resin. For example, acrylic resin such as carbonate resin, polymethyl methacrylate resin and acrylonitrile-styrene copolymer resin, polyethylene terephthalate, polyimide, polyethylene, polypropylene, alicyclic polyolefin resin, styrene resin, vinyl chloride resin, phenol resin One or two or more resins selected from the group consisting of melamine resins and epoxy resins can be exemplified. Of these, polycarbonate, acrylic resin, and the like can be preferably exemplified from the viewpoints of transparency and distortion prevention. Especially, in the front panel used for the touchscreen display for vehicle equipment, a polycarbonate is preferable from a viewpoint of scattering prevention.
The polycarbonate is not limited to a general aromatic polycarbonate mainly composed of bisphenol A. For example, an aromatic polycarbonate, an aliphatic polycarbonate, or an aromatic aliphatic polycarbonate mainly composed of another raw material can also be used. . For example, as a diol component, a polycarbonate containing an ether diol such as isosorbite as a main component is also included. Moreover, since the hardness of polycarbonate is not high, it is desired to improve the hardness by coating. Therefore, when polycarbonate is used as the base material for a panel member of the present invention, it is possible to more effectively enjoy the yuzu skin elimination and anti-glare of the coat layer.

(Shape and thickness of panel base material)
According to injection molding, a panel base member having an arbitrary shape and thickness can be formed. Thus, for example, as shown in FIG. 1, a substrate having a display surface portion 1 having a large number of irregularities and a peripheral portion 2 made of a smooth surface around the display surface portion 1 when viewed in plan. The panel base member 3 provided with the surface portion surface can be formed.
At this time, as shown in FIG. 1, the peripheral portion 2 may be formed with a peripheral edge portion as a curved surface or a wavy surface. Moreover, it is also possible arbitrarily to provide an opening such as a through hole, a concave portion, a convex portion, a rib, or the like at an appropriate portion of the peripheral portion 2. Further, various patterns such as a lattice pattern and a staggered pattern can be given to appropriate portions.

  In order to provide an anti-glare effect, it is preferable that the numerous irregularities formed on the surface of the display surface portion 1 be, for example, a fine irregular surface exhibiting a textured shape, that is, a textured surface.

The surface roughness (Rz) RzC of the surface of the display surface portion 1 is preferably 5 μm to 24 μm. If the RzC is 5 μm or more, it is preferable because a sufficient antiglare effect is obtained, and if it is 24 μm or less, it is preferable because the antiglare effect is too strong to further prevent the display from blurring.
From this point of view, the surface roughness (Rz) RzC of the surface of the display surface portion 1 is preferably 5 μm to 24 μm, more preferably 8 μm or more and 20 μm or less, and particularly preferably 12 μm or more or 18 μm or less.
The surface roughness (Rz) is a ten-point average roughness specified in JIS B 0601-1994, and is measured by, for example, a surface roughness measuring machine, a shape measuring machine, a tool microscope, a laser microscope, or other equipment. (The same applies to the surface roughness (Rz) described later.)

In addition, when the height of the unevenness on the surface of the display surface portion 1 is increased, it is possible to obtain an antiglare effect even if the thickness of the coat layer is increased. However, if the height of the unevenness is too large, the light of the liquid crystal panel may flicker.
From this viewpoint, the maximum height (Ry) of the unevenness on the surface of the display surface portion 1 is preferably 10 to 22 μm, more preferably 14 μm or more and 20 μm or less, and particularly preferably 16 μm or more or 18 μm or less.
The maximum height (Ry) is the maximum height specified in JIS B 0601-1994, and can be measured by, for example, a surface roughness measuring machine, a shape measuring machine, a tool microscope, a laser microscope, or other equipment. (The same applies to the maximum height (Ry) described later.)

On the other hand, the peripheral portion 2 is preferably a smooth surface in order to give a high-class feeling, and particularly preferably a mirror surface exhibiting gloss.
From this viewpoint, the surface roughness (Rz) of the surface of the peripheral portion 2 is preferably 8 μm or less, more preferably 6 μm or less, and more preferably 4 μm or less.

  From the above viewpoint, the surface of the peripheral portion 2 preferably has a specular gloss at an incident / reflecting angle of 60 ° based on JIS Z8741 of 85% or more, more preferably 90% or more.

  For example, when the front panel is used for a car navigation system or the like, the upper peripheral edge of the peripheral portion 2 may be a curved surface from the viewpoint of improving safety to a human body when a collision occurs (referred to as “collision safety”). .

(Injection molding)
In injection molding, an injection molding resin material is injected into a molding cavity of an injection mold, the molding cavity is filled with the resin material, and the filled resin material is cooled and solidified in the molding cavity. Then, the panel base member can be produced by opening the injection mold and taking out the injection molded product.

  As the injection mold, an injection mold mainly composed of a metal material may be used as in the conventional general injection mold.

When the resin material for injection molding filled in the molding cavity is solidified, an injection molded product having a surface shape corresponding to the shape of the inner surface (mold surface) of the injection mold facing the cavity is formed.
Therefore, for example, as described above, in order to form the panel substrate member 3 including the substrate surface portion having the peripheral portion 2 made of a smooth surface around the display surface portion 1 having a large number of irregularities, A mold molding cavity formed by male and female injection molds is formed so as to correspond to the form of the front panel, and the inner surface (mold surface) of the injection mold corresponds to the display surface portion 1. A surface shape corresponding to a large number of irregularities is formed in the part (also referred to as “display surface part forming part”), and a part corresponding to the peripheral part 2 (also referred to as “peripheral part forming part”) corresponds to the smooth surface. What is necessary is just to form a surface shape.

  More specifically, a large number of fine irregularities are formed on the display surface portion forming portion on the upper inner surface of one of the male and female dies, and a mirror surface is formed so as to surround the periphery, thereby forming a peripheral portion forming portion. In addition, the panel base member 3 including the peripheral portion 2 made of a smooth surface can be formed around the display surface portion 1 having a large number of irregularities on the surface.

As a method for imparting a concavo-convex shape to the inner surface of the mold, cutting processing (which may be NC processing), sand blasting or other physical treatment, etching treatment with an etching solution containing hydrofluoric acid, other chemical treatment, etc. Known techniques can be mentioned.
If necessary, it is preferable to polish the surface on which the concavo-convex pattern is formed with a grindstone or a polishing cloth (sandpaper). Moreover, it can grind | polish using a liquid or paste-form abrasive | polishing agent as needed.

In the sandblasting method, for example, an uneven surface can be formed by spraying particles such as alumina, silicon carbide, and gold sand together with air.
In the above etching method, for example, a hydrofluoric acid-based etching solution containing hydrofluoric acid, ammonium fluoride, an acid such as an inorganic acid such as sulfuric acid or nitric acid, an organic acid such as acetic acid or formic acid, water, and other additives. Can be used to form an uneven surface.

<Annealing process>
After injection molding, annealing may be performed by heating in order to reduce distortion and warpage generated in the panel base member.
As the annealing method, a known method can be used. For example, heat treatment may be performed so that the furnace temperature is maintained at 80 to 120 ° C. for 20 to 150 minutes in an air atmosphere. At this time, the furnace temperature and the product temperature are almost the same.

<Coating process>
In the coating step, a coating layer is formed by coating a transparent resin on the surface of the panel base member, that is, on the viewing side, for example, on the surface of the display surface portion 1 and the peripheral portion 2 of the panel base member 3.

(Coating method)
As a coating method of the transparent resin, for example, spin coating method, dipping coating method, spray method, slide coating method, bar coating method, roll coating method, gravure coating method, inkjet method, silk screen method, die coating method, flow coating method, A known coating method such as a cast transfer method can be used.
Among them, from the viewpoint of adjusting the thickness of the coat layer and coating separately, it is preferable to employ a spray method, an ink jet method, a gravure coat method, or a silk screen method. For example, a transparent resin is sprayed using a robot arm spray or the like. It is preferable to do this.

For example, adjustment of the amount applied when coating, adjustment of the number of times of application, adjustment of the distance to be coated, application pattern, and adjustment of the movement speed of the discharge port, or any one type of adjustment or two or more types By the combination of adjustment, the thickness of the coat layer 11 of the display surface portion 1 and the thickness of the coat layer 12 of the peripheral portion 2 can be adjusted.
More specifically, for example, if the robot arm spray is controlled by a computer, the operator can apply the coating amount and the number of coatings at each part according to the shape and size of the panel base member to be coated ( By inputting the number of times of coating) into the computer, the thickness of the coat layer 11 of the display surface portion 1 and the thickness of the coat layer 12 of the peripheral portion 2 can be adjusted to desired thicknesses.

(Features of coat layer)
In the coating step, the transparent resin is used so that the average value Aav of the thickness of the coat layer 11 of the display surface portion 1 and the average value Bav of the thickness of the coat layer 12 of the peripheral portion 2 have a relationship of Aav <Bav. It is preferable to coat.
In this way, the thickness of the coat layer 11 of the display surface portion 1 and the thickness of the coat layer 12 of the peripheral portion 2 are made different so that the thickness of the coat layer 11 of the display surface portion 1 having a large number of irregularities on the surface is determined. By making it larger than the thickness of the coat layer 12 in the peripheral portion 2, it is possible to prevent the occurrence of itchy skin in the peripheral portion 2 while maintaining the antiglare effect in the display surface portion 1.

It is preferable to coat the transparent resin so that the average value Aav of the thickness of the coat layer 11 of the display surface portion 1 is 5 μm to 10 μm.
If the average value Aav of the thickness of the coat layer 11 of the display surface portion 1 is 10 μm or less, a sufficient antiglare effect can be obtained. On the other hand, when the thickness is 5 μm or more, it is possible to further prevent the loss of image clarity. Moreover, sufficient strength as a coating film can be imparted.
From this viewpoint, the average value Aav of the thickness of the coat layer 11 of the display surface 1 is preferably 5 μm to 10 μm, more preferably 6 μm or more and 9 μm or less, and particularly preferably 7 μm or more or 8 μm or less.

On the other hand, it is preferable to coat the transparent resin so that the average value Bav of the thickness of the coating layer 12 in the peripheral portion 2 is 8 μm to 30 μm.
If the average value Bav of the thickness of the coating layer 12 in the peripheral portion 2 is 30 μm or less, the coating film shrinkage and the coating film damage with time can be prevented. On the other hand, if the thickness is 8 μm or more, it is possible to further prevent the occurrence of itchy skin.
From this viewpoint, the average value Bav of the thickness of the coat layer 12 in the peripheral portion 2 is preferably 8 μm to 30 μm, more preferably 10 μm or more and 25 μm or less, and particularly preferably 12 μm or more or 20 μm or less.

  In addition, the average value Aav of the thickness of the coat layer 11 and the average value Bav of the thickness of the coat layer 12 in the peripheral portion 2 may be measured as in Examples described later, or a scanning electron microscope (SEM). It can also be determined by observing the cross-sections of the coating layers 11 and 12 using an electron microscope such as the above, measuring the thickness of any three or more locations, and calculating the average value.

Furthermore, the surface roughness RzA of the coating layer of the display surface portion, the surface roughness RzB of the coating layer of the peripheral portion, and the surface roughness RzC of the display surface portion of the panel substrate member are expressed by the following relational expression ( It is preferable to coat the transparent resin so as to satisfy 1). If RzC, RzA and RzB satisfy the following relational expression (1) or (2), the antiglare effect is further enhanced, which is preferable.
(1) .. Surface roughness RzC> Surface roughness RzA = Surface roughness RzB
(2) .. Surface roughness RzC> Surface roughness RzA> Surface roughness RzB

(Resin composition)
The resin composition to be coated (referred to as “coat resin composition”) is not particularly limited as long as it is a transparent resin composition. Among these, a resin composition used as a hard coat material is particularly preferable.

  Examples of the hard coat resin composition include an ultraviolet (UV) curable resin composition, a solvent dry curable resin composition, and a thermosetting resin composition. However, other transparent hard coat materials can be used as appropriate.

Examples of the ultraviolet curable resin composition include a photopolymerizable compound, that is, a resin composition containing a compound having one or more photopolymerizable functional groups.
Further, examples of the light irradiated when polymerizing the photopolymerizable compound include visible light and ionizing radiation such as ultraviolet rays, X-rays, electron beams, α rays, β rays, and γ rays. .

  Examples of the photopolymerizable compound include a photopolymerizable monomer having an ethylenic double bond such as a polymerizable unsaturated bond such as an acryloyl group or a methacryloyl group, a thiol group, an epoxy group, or an allyl group in the molecule. A polymerizable oligomer or a photopolymerizable polymer can be mentioned. For example, a photopolymerizable monomer and a photopolymerizable oligomer or photopolymerizable polymer can be used in combination.

  Examples of the photopolymerizable monomer include a polyfunctional monomer having two (that is, bifunctional) photopolymerizable functional groups. For example, diethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tripropylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) Acrylate, dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, Dipentaerythritol penta (meth) acrylate, tripentaerythritol octa (meth) acrylate, tetrapentaerythritol deca ( Acrylate), isocyanuric acid tri (meth) acrylate, isocyanuric acid di (meth) acrylate, polyester tri (meth) acrylate, polyester di (meth) acrylate, bisphenol di (meth) acrylate, diglycerin tetra (meth) acrylate, adamantyl Di (meth) acrylate, isoboronyl di (meth) acrylate, dicyclopentane di (meth) acrylate, tricyclodecane di (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, and these modified with PO, EO, etc. Is mentioned.

  The photopolymerizable oligomer is preferably a bifunctional or higher polyfunctional oligomer. For example, polyether (meth) acrylate, polyol (meth) acrylate, melamine (meth) acrylate, isocyanate (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, urethane (meth) acrylate, polyester-urethane (meth) An acrylate etc. are mentioned.

  Examples of the photopolymerizable polymer include urethane (meth) acrylate, isocyanate (meth) acrylate, polyester-urethane (meth) acrylate, and epoxy (meth) acrylate.

  The ultraviolet curable resin composition contains a photopolymerization initiator, and the photopolymerization initiator absorbs ultraviolet rays and is excited and activated to cause a polymerization reaction, thereby curing the ultraviolet curable resin. The resin composition which raise | generates may be sufficient.

Examples of the photopolymerization initiator include benzyl, benzophenone and derivatives thereof, thioxanthones, benzyldimethylketals, αhydroxyalkylphenones, α-hydroxyacetophenones, hydroxyketones, aminoalkylphenones, acylphosphine oxides, and the like. Can be mentioned. Among these, α-hydroxyalkylphenones are preferable because they hardly cause yellowing during curing and a transparent cured product is obtained. In addition, aminoalkylphenones are preferable because they have very high reactivity and a cured product having excellent hardness can be obtained. The said photoinitiator can be used individually by 1 type or in combination of 2 or more types.
As for the addition amount of a photoinitiator, it is preferable to add 0.1-5 mass parts with respect to 100 mass parts of curable resin.

  In the case of an ultraviolet curable resin composition, for example, the resin composition is applied to the surface of the panel substrate, and then the resin composition is heated to dry to evaporate the solvent. The coat layer can be cured by irradiating the resin composition with light such as ultraviolet rays to polymerize (crosslink) the photopolymerizable compound. However, it is not limited to this method.

The solvent-drying curable resin composition may be a resin composition that forms a coating only by drying a solvent such as a thermoplastic resin added to adjust the solid content during coating.
Examples of the solvent-drying resin include a composition containing a transparent polyimide precursor varnish.

  Examples of the thermosetting resin composition include polyurethane resin, epoxy resin, phenol resin, urea resin, diallyl phthalate resin, melamine resin, guanamine resin, unsaturated polyester resin, aminoalkyd resin, and melamine-urea. The thing containing thermosetting resins, such as a condensation resin, a silicon resin, and a polysiloxane resin, can be mentioned.

The thermosetting resin composition contains, in addition to the thermosetting resin, for example, a curing agent such as a crosslinking agent and a polymerization initiator, a polymerization accelerator, a solvent, a viscosity modifier, an extender, and the like. Also good.
As the curing agent, isocyanate, organic sulfonic acid and the like are usually used for polyester resins and polyurethane resins, amine is epoxy resin, peroxide such as methyl ethyl ketone peroxide, radical initiator such as azobisisobutyl ester. Often used for unsaturated polyester resins.

Among these, from the viewpoint of scratch resistance, a coated resin composition having a pencil hardness of H or higher when coated on a polycarbonate substrate is preferable.
Further, the wettability (JISK6768) of the coating resin composition is preferably 22.6 dyn or less, and the viscosity (JISK5602-2 flow cuff type) of the coating resin composition is 7.5 seconds to 10.0 seconds. Is preferred.
From this viewpoint, the base resin of the coat resin composition is particularly preferably an acrylic resin or a urethane resin. Among these, acrylic resins are particularly preferable from the viewpoint of surface hardness.

  For the above-mentioned coating resin composition, conventionally known dispersants, surfactants, antistatic agents, silane coupling agents, thickeners, anti-coloring agents, coloring agents (pigments, dyes), antifoaming are necessary. Contains various additives such as additives, leveling agents, flame retardants, UV absorbers, adhesion promoters, polymerization inhibitors, antioxidants, surface modifiers, lubricants, antioxidants, impact modifiers, etc. be able to.

<Cutting process>
If necessary, the panel base member may be cut at a surplus portion so as to have a predetermined shape. For example, what is necessary is just to cut | disconnect the outer-periphery edge part of the surrounding part 2, and it should just make it the form of a panel base material.
The cutting process may be introduced before or after the coating process.

<Printing process>
The manufacturing method may include a printing step as necessary.
For example, a concealing portion may be formed around the display surface portion 1, that is, printing on the back surface of the panel base material corresponding to the surrounding portion 2, for example, black printing may be performed.
The printing process may be introduced before or after the coating process.

A mirror printing layer can also be provided by mirror printing.
By providing the mirror printing layer, a mirror effect can be given to give a good metallic feeling, an excellent design property can be given, and a high-class feeling can be given.

As a printing ink used for mirror printing, a silver printing ink in which a metal powder such as an aluminum powder or a silver powder is mixed and dispersed in a synthetic resin such as an acrylic resin, a urethane resin, or a polyester resin can be used.
As a printing method of such printing ink, printing methods such as screen printing, offset printing, gravure printing, flexographic printing and the like are used, and among these, screen printing is preferable.

It is also possible to provide a white print layer by applying white print on the mirror print layer.
This white printing is intended to prevent the slight pinholes remaining on the inner mirror printing layer, prevent light transmission, and suppress the metallic feel obtained by mirror printing due to pinholes. Yes, a normal printing ink containing a white colorant is used, and printing can be performed by screen printing or the like.

Further, mat-finished transparent printing or matte transparent printing can be performed.
Printing inks used for this type of application include transparent synthetic resins such as acrylic resins, urethane resins, and polyester resins as vehicles, and blended and dispersed with matting powders such as silica powder and alumina powder. A dry or ultraviolet curable transparent printing ink is preferred.
As a printing method for such transparent printing, printing methods such as screen printing, offset printing, gravure printing, flexographic printing, and the like can be used.

<Application>
This front panel can be used as it is for a front panel of a smartphone, a tablet terminal, a portable game device, or the like, or an operation panel of a car navigation system or an industrial machine.

<Explanation of words>
In the present specification, when expressed as “X to Y” (X and Y are arbitrary numbers), unless otherwise specified, “X is preferably greater than X” or “preferably Y”. It also includes the meaning of “smaller”.

  In addition, when expressed as “X or more” (X is an arbitrary number) or “Y or less” (Y is an arbitrary number), it is “preferably greater than X” or “preferably less than Y”. Includes intentions.

  Further, in the present specification, the “base resin” means a resin having the highest content among the resins constituting the resin composition, and usually 50% by mass or more of the resin constituting the resin composition, Among them, the resin is 80% by mass or more, and among them, the resin is 90% by mass or more (including 100% by mass). However, when the resin composition contains two types of base resins, the total amount is the mass ratio.

In the present specification, the “front side” is a side from which display light from the front panel is emitted, and means a side on which the display on the front panel is observed.
The “back side” means the side opposite to the “front side” and means the side on which the display light of the front panel enters.
The term “transparent” is not limited to colorless and transparent, but includes colored and transparent.

  Hereinafter, the present invention will be described in more detail based on the following examples and comparative examples.

<Preparation of panel substrate>
An injection mold that has a cavity corresponding to the shape of the in-vehicle display front panel, the mold surface corresponding to the viewing surface of the display surface is a textured surface, and the mold surface corresponding to the surface of the surrounding surface is a mirror surface Prepared.

An injection molding resin material containing polycarbonate as a base resin was prepared. The injection-molding resin material was filled into the mold cavities and cooled and solidified to mold a panel base material member made of polycarbonate.
Next, after removing the surplus portion of the panel base material member thus obtained, annealing was performed while maintaining the furnace temperature at 100 ° C. for 700 minutes in an air atmosphere, and the panel base material ( Sample).

As shown in FIG. 1, the obtained panel base material (sample) has a display surface portion 1 having a large number of irregularities on the surface, and a smooth surface around the display surface portion 1 so as to surround the display surface portion 1 when viewed in plan. It was the member formed by forming the surrounding part 2.
The maximum height (Ry) of the unevenness on the surface of the display surface portion 1 was 22 μm, and that of the peripheral portion was 4 μm.
Further, black printing was performed on the back surface of the peripheral portion 2 by silk screen printing.

<Example 1-5 and Comparative Example 1-2>
Using a robot arm spray, the surface of the display surface portion 1 and the peripheral portion 2 of the panel base material (sample) was coated with a transparent resin A to form a coat layer, thereby producing a front panel (sample). At this time, the thickness of the coat layer 11 on the display surface 1 and the thickness of the coat layer 12 on the peripheral portion 2 are displayed by inputting the spray amount and the number of times of coating at each position to a computer that controls the robot arm spray. As shown in FIG.
As the transparent resin A, an acrylic resin (viscosity 8.0 seconds) was used. This viscosity is a value measured using an NK2 cuff manufactured by Anest Iwata in accordance with the JISK5602-2 flow cuff formula.
Further, the pencil hardness on the surface of the coating layer was 2H in any of the examples and comparative examples.

(Measurement of average thickness of coat layer)
The coating layers 11 and 12 are formed on the metal plate in the same manner as in the example, and the coating is performed at any three locations using an electromagnetic induction type film thickness measuring device (“Permascope MPOD” manufactured by Kett Chemical Laboratory Co., Ltd.). The thicknesses of the layers 11 and 12 were measured, and the average values were taken as average values Aav and Bav, respectively.

(Measurement of surface roughness)
The surface roughness of the surface of the panel substrate (sample) and the surface roughness of the surface of the coat layer on the front panel (sample) were measured by a surface roughness meter (product name “SURFCOM (registered trademark)” manufactured by Tokyo Seimitsu Co., Ltd. NEX ") and a stylus with a tip diameter of 5 μm were used to measure the ten-point average roughness (Rz) and maximum height (Ry) of the surface according to JISB0601: 1994.

(Measurement method of haze)
Using a double beam type haze computer “HGM-2B” manufactured by Suga Test Instruments Co., Ltd., haze was measured in accordance with JISK7136.

(Evaluation of anti-glare property of display surface)
With respect to the display surface portion of the front panel (sample) produced in Examples and Comparative Examples, the fluorescent lamp was reflected on the display surface, and the sharpness of the fluorescent lamp reflected and reflected was visually observed and evaluated according to the following criteria.
◎ (very good): Fluorescent lamps appear moderately blurred ○ (good): Fluorescent lamps appear blurred, but the degree of blurring is not enough × (poor): Fluorescent lamps appear clear

(Evaluation of Yuzu skin around)
About the peripheral part of the front panel (sample) produced by the Example and the comparative example, light was reflected to the outer peripheral part, the uneven feeling of the coating surface was observed, and the following reference | standard evaluated.
◎ (very good): It was smooth without unevenness.
○ (good): Although fine unevenness remained, it was almost smooth.
X (poor): There was a feeling of unevenness.

From the above-mentioned examples and the test results that the inventor has conducted so far, the thickness of the coat layer of the display surface portion and the thickness of the coat layer of the peripheral portion have a difference, and the display surface portion having a large number of irregularities on the surface. It has been found that by making the thickness of the coat layer relatively large, it is possible to prevent the generation of the yuzu skin on the smooth surface while maintaining the antiglare effect on the display surface portion.
From this viewpoint, it is found that the average value Bav of the coating layer in the peripheral portion is preferably greater than 10 μm and not more than 30 μm, and the average value Aav of the thickness of the coating layer in the display surface portion is preferably 5 μm to 10 μm. It was.

  In addition, although the maximum height (Ry) of the unevenness | corrugation of the surface of the display surface part 1 of the base material used in the said Example was 22 micrometers, from the test result which the inventor performed so far, it is 10-22 micrometers. If there is, the same effect can be obtained, and it can be considered that it is more preferably 14 μm or more and 20 μm or less, particularly preferably 16 μm or more or 18 μm or less.

DESCRIPTION OF SYMBOLS 1 Display surface part 2 Perimeter part 3 Panel base material 4 Printing part 11 Coat layer 12 Coat layer

Claims (10)

A base material injection molding step of forming a panel base material member having a display surface portion having a number of irregularities and a base material surface portion having a smooth surface around the display surface portion by injection molding; and A method of manufacturing a front panel comprising a coating step of coating a transparent resin on the display surface portion and the peripheral surface of the panel base member to form a coat layer,
A transparent resin is coated such that the average value Aav of the thickness of the coat layer on the display surface portion and the average value Bav of the thickness of the coat layer on the peripheral portion have a relationship of Aav <Bav. Panel manufacturing method.   2. The method for manufacturing a front panel according to claim 1, wherein the transparent resin is coated so that an average value Bav of a thickness of the coating layer in the peripheral portion is 8 μm or more and 30 μm or less.   The method for producing a front panel according to claim 1 or 2, wherein the transparent resin is coated so that an average value Aav of a thickness of the coating layer of the display surface portion is 5 µm or more and 10 µm or less.   The method for producing a front panel according to any one of claims 1 to 3, wherein the coating layer is formed by applying a transparent resin by a spray method, an inkjet method, a gravure coating method, or a silk screen method.   Adjustment of the amount applied when coating, adjustment of the number of times of application, adjustment of the distance of the object to be coated, application pattern, adjustment of the moving speed of the discharge port, one type of adjustment or two or more types of adjustment 5. The method for manufacturing a front panel according to claim 1, wherein the thickness of the coat layer on the display surface portion and the thickness of the coat layer on the peripheral portion are adjusted by the combination.   The method for manufacturing a front panel according to claim 1, wherein the viewing side surface of the display surface portion of the panel base member is a textured surface.   The front panel manufacturing method according to claim 1, wherein a surface of a peripheral portion of the panel base member is a mirror surface. The surface roughness RzA of the coating layer of the display surface portion, the surface roughness RzB of the coating layer of the peripheral portion, and the surface roughness RzC of the display surface portion of the panel substrate member are expressed by the following relational expression (1). Or the transparent resin is coated so that (2) may be satisfy | filled, The manufacturing method of the front panel in any one of Claims 1-7 characterized by the above-mentioned.
(1) .. Surface roughness RzC> Surface roughness RzA = Surface roughness RzB
(2) .. Surface roughness RzC> Surface roughness RzA> Surface roughness RzB   The manufacturing method of the front panel in any one of Claims 1-8 provided with the printing process which prints on the back surface of the member for panel base materials.   The said front panel is a front panel used for the touchscreen display for vehicle equipment, The manufacturing method in any one of Claims 1-9 characterized by the above-mentioned.

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