JP5531782B2 - Housing, housing manufacturing method, electronic device, and electronic device manufacturing method - Google Patents

Description

  The present invention relates to a housing and a manufacturing method thereof, an electronic device using the housing, and an electronic device manufacturing method using the housing.

  In addition to improving the surface strength of the case that houses various small electronic devices such as mobile phones, PDAs, and notebook PCs, the surface of the case is secondarily decorated to differentiate products. It has been done.

  The method of decorating the surface of the casing fabric, which is a molded object to be coated, made of metal or resin material, is further divided into two methods: painting methods and decorative sheets There is a sticking method.

  One of the so-called coating methods, that is, the method of adhering a liquid paint or powder paint to the surface of a molded object to be coated, is to apply various colors to the surface of the molded object having a three-dimensional shape. It is possible. By adjusting the content of the resin component and additives contained in the paint, it is possible to adjust the coating film hardness and to give a certain degree of coating texture.

  However, with such a coating method, it is difficult to obtain a surface texture with a specific texture such as the surface of leather, cloth, wood, etc., which is soft, elastic, or warm. In order to give leather or cloth texture to the surface of the housing for electronic devices, a sheet of such material itself, or a leather-like or wood-like sheet (decorative sheet) resembling the texture, adhesive, etc. A so-called sheet pasting method, which is another decoration method for pasting via a sheet, is performed.

  In the decorative method by the sheet sticking method, when the molded object to be coated has a three-dimensional shape, not only the sheet of the material itself such as wood and leather, but also the decorative sheet similar to it, the corner portion and the rising ( It is very important from the aesthetic point of view to accurately follow the adhesion of the sheet to the (falling) portion.

As a method for attaching a material sheet such as leather or a decorative sheet such as leather to the surface of a molded object to be coated such as a casing, the following method can be considered.
(1) Manual work: Can be affixed to the surface of the casing fabric, which is a molded object to be coated, without damaging the texture of a soft material sheet such as leather or cloth (or a decorative sheet resembling it) . However, there is a problem that the manufacturing quality is affected by the skill level of the worker and the productivity is low.
(2) Press working; since the sticking is performed with a mechanical pressure and an adhesive using a mold, the variation in quality by the operator can be eliminated. However, since the material is crushed, the texture of the soft material is easily lost both in appearance and in touch, and the mold itself is also expensive.
(3) Vacuum forming (vacuum / pressure forming): This method is performed, for example, in the following steps. In an apparatus in which two sealed spaces formed by a non-breathable decorative sheet made of synthetic resin, for example, are formed, on one sealed space side, in this case, a casing that is a molded object to be coated is provided. Then, both the sealed spaces are evacuated and vacuumed, and then the decorative sheet is radiantly heated with a heater or the like.

  Here, the molded body surface is pressed against the decorative sheet adhesion surface from one sealed space side to the other sealed space side, and the other sealed space on the side where the molded body is not disposed in this pressed state. Only return to normal pressure. Thereby, an external pressure is uniformly applied to the decorative sheet, and the decorative sheet can be stuck on the surface of the molded body.

  In the above process, without using the process of pressing the molded body against the decorative sheet adhesive surface from one sealed space side to the other sealed space side, simply place one sealed space side in a vacuum and mold A method in which only the other sealed space on the side where the body is not placed is returned to normal pressure so that the decorative sheet is attached to the surface of the shaped fabric is also possible depending on the application conditions. The above method is called a vacuum forming method. In the above, one side of the sealed space is evacuated, only the other sealed space is returned to normal pressure, a decorative sheet is attached to the molded body, and then compressed air is introduced from the normal pressure by introducing compressed air. It is also possible to make sure that the sticking is done. This is called a vacuum / pressure forming method.

  Among the above three methods, as a method of applying a decorative sheet using a resin material sheet to a molded article having a three-dimensional shape, including the point of productivity, the texture when a soft sheet is applied is used. In view of maintaining good quality, (3) vacuum forming (vacuum / pressure forming) is considered the most preferable method.

WO2008 / 053527 JP 2009-18548 A JP 2002-79573 A

  The decorative sheet sticking step by vacuum / pressure forming described above will be described with reference to FIG. A vacuum / pneumatic forming apparatus 101 shown in FIGS. 2 (1) and 2 (2) has a first sealed space 102 (lower side) substantially partitioned by a decorative sheet 108 fixed to a wall surface of the apparatus by a clamp 107. And a second sealed space 103 (upper side). In the lower first sealed space 102, there is a covering molded body 106 fixed to the stage 104, and the decorative sheet 108 is stuck on the surface of the covering molded body 106. The first sealed space 102 (lower side) and the second sealed space 103 (upper side) are, respectively, an exhaust valve directly connected to the vacuum exhaust device, an atmospheric pressure release valve that opens the vacuum pressure to atmospheric pressure, not shown. And a compressed air introduction valve directly connected to the compressed air pump. In addition, a heater 111 for heating the second sealed space 103 with radiant heat is provided above the decorative sheet 108. The decorative sheet 108 is generally composed of a decorative layer 109 made of a resin sheet on which a decorative pattern or the like is printed, and an adhesive layer 110 using an adhesive for bonding the decorative layer 109.

  In FIG. 2 (1), first of all, the first and second sealed spaces 102 and 103 are set in the atmosphere, the covering molded body 106 is set on the stage 104, and the decorative sheet 108 is attached to the clamp 107. Both the first and second sealed spaces 102 and 103 are evacuated (vacuum process). Then, in a vacuum state, the heater 111 is energized to heat the decoration sheet 108, and the decoration layer 109 including the adhesive layer 110 of the decoration sheet 108 is softened. After the energization of the heater 111 is stopped, as shown in the drawing, an air release valve (not shown) in the second sealed space 103 is opened and air is introduced, so that the decorative sheet 108 is first and the first closed space 102 is closed. A pressure P is applied in the direction, and it expands slightly downward (in the direction of the first sealed space 102).

  Next, as shown in FIG. 2 (2), the stage 104 is moved M (in the direction of the second sealed space 103) by a driving device (not shown) of the first sealed space 102, so that the covering molded body 106 is attached to the decorative sheet. 108 is pressed from the side of the adhesive layer 110 toward the second sealed space 103. A pressure P is applied to the decorative sheet 108 from the second sealed space 103 side in a normal pressure state. Here, further, compressed air is introduced from a compressed air introduction valve directly connected to a compressed air pump (not shown), The pressure P is increased (compressed air process).

  At this time, since air is exhausted through the air passage 105 as well, a phenomenon in which air is trapped between the decorative sheet 108 and the surface of the covering molded body 106 can be eliminated.

  In this way, the entire decorative sheet 108 is firmly stuck on the surface of the coated molded body 106, and both the sealed spaces are returned to the normal pressure state, and then the coated molded body 106 decorated with the decorative sheet is removed from the vacuum / pressure device. Take out and achieve the intended purpose.

  The decorative sheet is pasted in such a manner that the corner portion and the rising portion of the covering molded body 106, which is a three-dimensional body, are not sharp and the thickness of the decorative sheet is thinner. Affixing faithful to the surface shape of the molded body 106 can be realized.

  However, a resin foam sheet is formed on a sheet-shaped resin woven fabric or resin nonwoven fabric, and a resin decorative sheet on which a printed pattern is formed is further laminated, such as leather or cloth. In the case of decorative sheets that express a soft texture (these are called leather-like decorative sheets), they have a relatively thick structure as a whole, and sticking this faithfully to the three-dimensional structure of the coated molded body It's not easy.

  FIG. 3 schematically shows an example of a forming cross-sectional view when vacuum forming or vacuum / pressure forming is performed using a conventional leather-like decorative sheet.

  FIG. 3 (1) shows a schematic cross-sectional view of a typical conventional leather-like decorative sheet. The conventional leather-like decorative sheet 112 has a non-foamed resin layer 113 made of, for example, a urethane resin having a thickness of several μm, on which a leather-like pattern is printed, and a leather-like texture, for example. The foamed resin layer 114 is made of a urethane foam resin with a thickness of several tens to several hundreds of μm, which has an appropriate thickness and unevenness for giving a touch, and further, for example, a leather-like feel is further provided thereunder. A sheet in which a woven or non-woven fiber layer 115 made of polyester resin fibers having a thickness of several tens to several hundreds of μm and having a suitable strength and cushioning property, which can be emphasized, is laminated. Adhesion made of a pressure sensitive adhesive such as an acrylic resin having a thickness of several tens of μm, for example, to be applied to the surface of a coated molded body (for example, a cloth made of metal or resin of an electronic device casing) by the above molding method Tier 1 6 is applied and formed.

  FIG. 3 (2) is a cross-sectional view of the main part schematically showing the results when vacuum forming or vacuum / pressure forming is performed using this conventional leather-like decorative sheet 112. FIG. In this figure, when the conventional leather-like decorative sheet 112 is vacuum-formed or vacuum-pressure formed on the surface of the covering molded body 106 to be applied on the stage 104, the adhesive layer 116 adheres to the surface of the covering molded body 106. However, since the resin material layer (the non-foamed resin layer 113, the foamed resin layer 114, and the fiber layer 115) of the decorative sheet contracts due to the residual stress at the time of molding, the exposure of the surface of the coated molded body 106 from the end surface, the decorative sheet, If the covering formed body 106 is particularly thin, deformation such as warping of the coating may occur. In particular, the occurrence of wrinkles on the decorative sheet is often seen particularly at the rising and falling portions and the refracting portions.

  Therefore, the problem to be solved by the present invention is particularly that a leather-like decorative sheet that is relatively thick and has a fiber layer or the like, for example, a coating made of metal or resin that is a fabric of a housing for an electronic device. A case in which shrinkage, peeling, wrinkles, warpage, and the like of the decorative sheet are suppressed when the electronic device case is decorated by vacuum forming or vacuum / pressure forming on the surface of the formed product, and its manufacture An object is to provide a method, an electronic device using a housing, and a manufacturing method thereof.

The housing of the present invention is
A coating covered with a decorative sheet, in which a foamed resin layer and a non-foamed resin layer are sequentially laminated on one surface side of the fiber layer, and a shrinkage-suppressing adhesive layer impregnated on the other surface side of the fiber layer is formed. It has a molded body surface.

Moreover, the manufacturing method of the housing of the present invention includes:
A method for manufacturing a housing, comprising:
A step of laminating a foamed resin layer and a non-foamed resin layer in order on one side of the fiber layer, and forming a shrinkage-suppressing adhesive layer on the other side of the fiber layer to form a decorative sheet;
And a step of vacuum forming or vacuum / pressure forming the decorative sheet on the surface of the casing of the casing.

  According to the method of the present invention, in particular, when using a leather-like decorative sheet or the like and vacuum-pressing the sheet and pasting the sheet, there was no pasting wrinkle or shrinkage / peeling of the end face, and warping It is possible to manufacture a housing that does not occur.

The figure explaining the structure of the decoration sheet of this invention, and a shaping result using the same Illustration of vacuum pressure forming method The figure explaining the structure of the conventional decoration sheet | seat, and a shaping result using the same

Hereinafter, embodiments of the present invention will be described.
(Production of Examples and Comparative Examples)
The production method according to the present invention (Example) and the conventional production method (Comparative Example), and the materials used and the treatment methods in each method are shown.
(1) Common coated molded body; notebook PC cover (made of magnesium alloy, size: 260 × 180 mm)
(2) Leather-like decorative sheet synthetic resin material; commercially available synthetic leather sheet (made of synthetic resin, width size: 500 mm, thickness: about 0.8 mm)
Layer structure of resin material Urethane non-foamed resin layer: 30 μm thickness, urethane foam resin layer: 50 μm thickness,
Polyester resin woven fabric fiber layer: 400 μm thick,
(3) Vacuum pressure forming apparatus; NGF-0709 manufactured by Fuse Vacuum Co., Ltd.
(4) Adhesive;
-Thermoplastic adhesive used in the present invention: Synthetic rubber adhesive (produced by Cemedine Co., Ltd., HM650-2, nitrile rubber), melting temperature 100 ° C)
General pressure-sensitive adhesive used in comparative examples: acrylic pressure-sensitive adhesive (manufactured by Toa Gosei Co., Ltd., Aron Tack S3452, dilution solvent: ethyl acetate), isocyanate for curing agent (Asahi Kasei Chemicals Corporation, Duranate 24A-100)
(5) Inorganic fine particles used and their mixing;
・ Silica (Jujo Chemical Co., Ltd., JA-244) was added to each adhesive at 15 wt%.

When mixed into the thermoplastic adhesive, silica is mixed and dispersed when the adhesive is melted and applied to the sheet.
(6) Method for forming an adhesive layer by applying an adhesive;
-The thermoplastic adhesive used in the present invention is prepared by using a hot melt applicator while heating the leather-like decorative sheet synthetic resin material to about 80 ° C (after mixing it in the case of using fine particles). Apply and dry naturally.

  -The impregnation treatment into the woven fabric layer is a heat treatment at a furnace body temperature of about 110 ° C. (3 minutes).

  ・ A roll coater is used for the acrylic adhesive used in the comparative example. When impregnating into the woven fiber layer, the coating is performed with 1.5 times the diluent ethyl acetate.

・ Applying the thickness of each pressure-sensitive adhesive with the aim of coating with a remaining film thickness of about 30 μm on the surface of the woven fiber layer after soaking. The substantial amount of the coating solution is about three times the surface coating thickness because of the impregnation into the woven fiber layer.
(Characteristic results of examples of the present invention and comparative examples)
"Comparative example"
A: Acrylic adhesive + no impregnation treatment Adhesive layer thickness: 35 μm
Shape tracking; wrinkle adhesion; end face shrinkage, some peeling; dimensionality; no warpage

B: Acrylic adhesive + impregnation treatment Adhesive layer thickness: 15 μm
Shape tracking; wrinkle adhesion; end face shrinkage, some peeling, dimensionality; no warpage

C: Acrylic adhesive + 15 wt% silica mixed + impregnation treatment Adhesive layer thickness: 30 μm
Shape tracking; wrinkle adhesion; no end face shrinkage , slight peeling Dimensionality; warpage

"Example"
D: Synthetic rubber adhesive + impregnation treatment Adhesive layer thickness: 30 μm
Shape followability; wrinkle-free adhesion; slight shrinkage of end face; no peeling dimensionality; warpage

E; synthetic rubber adhesive + silica 15 wt% mixed + impregnated There adhesive layer thickness; 35 [mu] m
Shape followability; no wrinkle adhesion; no end surface shrinkage, no peeling dimensionality; no warpage

From the above results of “A” to “E”, as in the method “E” which is the method of the present invention, a thermoplastic synthetic rubber-based pressure-sensitive adhesive is used as the pressure-sensitive adhesive, and a silica of a fine particle material is used for this. After applying the mixture to the fiber layer, it is further immersed in the fiber layer to form an adhesive layer. With this adhesive layer, vacuum pressure forming is performed and a decorative sheet is pasted. In addition, it is shown that an electronic device casing is manufactured in which there is no contraction / peeling of the end face and no warping occurs.

  FIG. 1 schematically shows an example of a forming cross-sectional view when vacuum-forming or vacuum-pressure forming is performed using the leather-like decorative sheet used in the present invention.

  FIG. 1 (1) shows a schematic cross-sectional view of the leather-like decorative sheet of the present invention. The leather-like decorative sheet 1 of the present invention is, from the surface side, similarly to the conventional example, for example, a non-foamed resin layer 2 made of a urethane resin having a thickness of several μm on which a leather-like pattern is printed, In addition, for example, a foamed resin layer 3 made of urethane foamed resin having a thickness of several tens to several hundreds of μm, which has an appropriate thickness and unevenness for giving a leather-like texture and feel, for example, In addition, a woven or non-woven fiber layer 4 made of polyester resin fibers having a thickness of several tens to several hundreds μm, which has a moderate strength and cushioning property, and which can emphasize a leather-like feel is laminated. In the present invention, as the layer for adhesion, an inorganic layer such as silica is provided in the vicinity of the surface of the fiber layer 4 as shown in the drawing. Synthetic rubber mixed with fine particles Viscosity adhesive impregnated, adhesive layer 5 is formed shrinkage control.

  As described above, the shrinkage-suppressing adhesive layer 5 is formed in a state where inorganic fine particles are included in the fiber layer together with the pressure-sensitive adhesive (synthetic rubber), and this serves as an adhesive layer with the coated molded body. At the same time, the shrinkage of the resin material layer of the decorative sheet due to the residual stress after molding is suppressed or alleviated. As a result, as shown in FIG. 1 (2), the leather-like decorative sheet 1 of the present invention attached to the surface of the covering molded body 7 on the stage 6 by a vacuum / pressure forming method is shown in the conventional example of FIG. The shrinkage difference phenomenon generated between the adhesive layer 116 and the fiber layer 115 is not observed, and there is no peeling due to separation of the adhesive layer (in this case, the shrinkage-suppressing adhesive layer 5) and the fiber layer, and the coated molded body 7 It is possible to prevent the surface of the base that is the surface of the substrate from being exposed. Moreover, from this effect, generation | occurrence | production of a wrinkle and generation | occurrence | production of curvature are suppressed.

  In the case of an acrylic pressure-sensitive adhesive, even if inorganic fine particles are added thereto and an adhesive layer impregnated in the fiber layer is formed, a sufficient compression suppressing effect cannot be obtained. Peeling remains and warping occurs. This is thought to be because, compared with a rubber-based pressure-sensitive adhesive of thermoplastic resin, the pressure-sensitive adhesive itself is hardly cured after sticking the sheet, and shrinkage / deformation cannot be suppressed.

  Applying and impregnating a thermoplastic adhesive to the fiber layer of a leather-like decorative sheet synthetic resin material is particularly convenient for applying heat during vacuum / pressure forming and melting / softening it. This is because it can be applied in a three-dimensional shape without impairing the sex. The thermoplastic adhesive is preferably a resin based on a synthetic rubber (for example, nitrile rubber, styrene rubber, chloroprene rubber, etc.). This is because the softening temperature is around 100 ° C., which is close to the temperature at which the leather-like decorative sheet synthetic resin material is softened, and the molding process becomes easy. For example, the pressure-sensitive adhesive based on olefin resin has a relatively high softening temperature of about 130 ° C. Therefore, heating above the softening temperature of the leather-like decorative sheet synthetic resin material is necessary to exert this adhesive force. It is not preferable.

  The thickness of the shrinkage suppression adhesive layer is preferably 30 to 50 μm from the surface. If it was too thick or too thin, sufficient adhesion to the surface of the coated molded body during vacuum / pressure forming was not obtained.

  As the inorganic fine particles, glass systems such as silica, glass beads and glass flakes are desirable. Compared to metal or mineral particles, it can be easily dispersed uniformly in the pressure-sensitive adhesive, so the addition rate can be arbitrarily changed. The addition rate is desirably 10 to 30 wt%.

  The size of the fine particles is preferably about several μm to 10 μm for the representative dimension for uniform dispersion and mixing when the thickness of the adhesive layer in the fiber layer (thickness of the shrinkage suppression adhesive layer) is 30 to 50 μm. If the size is too large, it is difficult to impregnate, and if it is too small, it tends to aggregate.

  In the above-described embodiments, an electronic device casing in which a leather-like decorative sheet is mainly used and a covering molded body is attached to the surface of a metal (magnesium alloy) casing base by applying a vacuum / pressure forming method, and The manufacturing method was described, and as a result, it was shown that a great effect could be obtained. Needless to say, within the scope of the present invention, the present invention is not limited to the materials and specific manufacturing apparatuses used in the above-described embodiments.

  The sticking sheet to be used does not need to be a “leather-like decorative sheet”, and the structure of the sticking sheet is not limited to woven or non-woven cloth, but may be a sheet in which the fiber layer is in contact with the adhesive layer. Thus, the application of the method of the present invention and the apparatus of the present invention can be obtained. The coated molded body (the surface thereof) can be applied not only with metal but also with plastic, for example. Furthermore, although the sticking method has been described mainly by the vacuum / pressure forming method, it may be a vacuum forming method.

The following additional notes are disclosed regarding the embodiments including the above examples.
(Appendix 1)
A coating covered with a decorative sheet, in which a foamed resin layer and a non-foamed resin layer are sequentially laminated on one surface side of the fiber layer, and a shrinkage-suppressing adhesive layer impregnated on the other surface side of the fiber layer is formed. A housing having a molded body surface.
(Appendix 2)
The casing according to appendix 1, wherein the shrinkage suppression adhesive layer includes a thermoplastic pressure-sensitive adhesive and inorganic fine particles.
(Appendix 3)
The casing according to appendix 2, wherein the inorganic microparticles are glass-based microparticles.
(Appendix 4)
The casing according to appendix 2 or 3, wherein the thermoplastic adhesive is an adhesive having a synthetic rubber as a base resin.
(Appendix 5)
A method for manufacturing a housing, comprising:
A step of laminating a foamed resin layer and a non-foamed resin layer in order on one side of the fiber layer, and forming a shrinkage-suppressing adhesive layer on the other side of the fiber layer to form a decorative sheet;
And a step of vacuum forming or vacuum / pressure forming the decorative sheet on the surface of the cover molded body of the casing.
(Appendix 6)
The formation of the shrinkage-suppressing adhesive layer is a step of applying and impregnating a mixed pressure-sensitive adhesive in which inorganic fine particles are mixed and dispersed in a thermoplastic pressure-sensitive adhesive to the other surface side of the fiber layer. The method for manufacturing the housing according to Appendix 5.
(Appendix 7)
The method for manufacturing a casing according to appendix 6, wherein the thermoplastic adhesive is an adhesive having a synthetic rubber as a base resin.
(Appendix 8)
The method for manufacturing a casing according to appendix 6 or 7, wherein the inorganic microparticles are glass-based microparticles.
(Appendix 9)
A coating covered with a decorative sheet, in which a foamed resin layer and a non-foamed resin layer are sequentially laminated on one surface side of the fiber layer, and a shrinkage-suppressing adhesive layer impregnated on the other surface side of the fiber layer is formed. An electronic apparatus using a casing having a molded body surface.
(Appendix 10)
A method of manufacturing an electronic device,
The electronic device has a casing, and the manufacturing method of the casing includes:
A step of laminating a foamed resin layer and a non-foamed resin layer in order on one side of the fiber layer, and forming a shrinkage-suppressing adhesive layer on the other side of the fiber layer to form a decorative sheet;
And a step of vacuum forming or vacuum / pressure forming the decorative sheet on the surface of the cover molded body of the casing.

DESCRIPTION OF SYMBOLS 1 Leather-like decorative sheet of the present invention 2, 113 Non-foamed resin layer 3, 114 Foamed resin layer 4, 115 Fiber layer 5 Shrinkage suppressing adhesive layer 6, 104 Stage 7, 106 Cover molded body 101 Vacuum / pressure air molding apparatus 102 First Sealed space 103 Second sealed space 105 Ventilation path 107 Clamp 108 Decorative sheet 109 Decorative layer 110 Adhesive layer 111 Heater 112 Conventional leather-like decorative sheet 116 Adhesive layer

Claims (8)

A coating covered with a decorative sheet, in which a foamed resin layer and a non-foamed resin layer are sequentially laminated on one surface side of the fiber layer, and a shrinkage-suppressing adhesive layer impregnated on the other surface side of the fiber layer is formed. the molded body surface possess, the shrinkage suppression adhesive layer, characterized in that it comprises a thermoplastic adhesive and the inorganic fine particles housing. The casing according to claim 1, wherein a thickness of the shrinkage suppression adhesive layer is 30 to 50 μm from the surface . The inorganic microparticles housing of claim 1, wherein it is a glass-based fine particles.   The casing according to claim 2 or 3, wherein the thermoplastic adhesive is an adhesive having a synthetic rubber as a base resin. A method for manufacturing a housing, comprising:
A foamed resin layer and a non-foamed resin layer are sequentially laminated on one surface side of the fiber layer, and a shrinkage suppression adhesive layer containing a thermoplastic pressure-sensitive adhesive and inorganic fine particles is formed on the other surface side of the fiber layer. Forming a decorative sheet;
A process for vacuum forming or vacuum / pressure forming the decorative sheet on the surface of the covering molded body of the electronic device casing. 6. The method of manufacturing a housing according to claim 5, wherein the shrinkage-suppressing adhesive layer is a step of forming a thickness of 30 to 50 [mu] m from the surface . A coating covered with a decorative sheet, in which a foamed resin layer and a non-foamed resin layer are sequentially laminated on one surface side of the fiber layer, and a shrinkage-suppressing adhesive layer impregnated on the other surface side of the fiber layer is formed. An electronic apparatus using a casing having a molded body surface , wherein the shrinkage-suppressing adhesive layer contains a thermoplastic adhesive and inorganic fine particles . A method of manufacturing an electronic device,
The electronic device has a casing, and the manufacturing method of the casing includes:
A foamed resin layer and a non-foamed resin layer are sequentially laminated on one surface side of the fiber layer, and a shrinkage suppression adhesive layer containing a thermoplastic pressure-sensitive adhesive and inorganic fine particles is formed on the other surface side of the fiber layer. Forming a decorative sheet;
And a step of vacuum forming or vacuum / pressure forming the decorative sheet on the surface of the cover molded body of the casing.