WO2013031055A1 - External housing of electric instrument and method for manufacturing same - Google Patents

Abstract

On a substrate (13) comprising a resin composition containing a resin component including 50 wt% or more of a polylactic acid and/or lactic acid copolymer, as well as an optional reinforcing filler and a fire-resistance-imparting component, a decorative sheet (14) having a decorative layer (15) provided on one surface of a sheet comprising the resin composition containing the resin component, including 50 wt% or more of a polylactic acid and/or lactic acid copolymer, is affixed so that the decorative layer (15) and the substrate (13) face each other. An external housing of an electric instrument is formed.

Description

Exterior body of electrical equipment and manufacturing method thereof

The present invention relates to an exterior body used for electric appliances such as thin and light flat display devices, and general electronic parts such as resistors and speakers, and a method for manufacturing the same.

Liquid crystal displays, organic EL displays, plasma displays, etc. have been commercialized as flat display devices. In particular, a liquid crystal display and a plasma display are thin and can display a large screen, so that they are widely used as displays in public facilities as well as general homes.

In such a display device, a resin molded product is used as an exterior body in order to satisfy a design requirement and to reduce the weight. As these display devices become widespread, disposal of resin molded products when disposed after use is becoming a problem.

In recent years, resins (or plastics) that are decomposed by bacterial action when buried in the soil have attracted attention. These resins, called biodegradable resins (or biodegradable plastics), have the property of degrading into water (H ₂ O) and carbon dioxide (CO ₂ ) in the presence of aerobic bacteria. Biodegradable resins have been put to practical use in the agricultural field, and have been put to practical use as materials for disposable packaging materials and compostable garbage bags.

For example, when a product using a biodegradable resin is used in the agricultural field, there is no need to collect used plastic, which may be convenient for the user. Furthermore, in recent years, plant-derived resins are also attracting attention in the fields of electronic devices and automobiles. Plant-derived resins are obtained by polymerizing or copolymerizing monomers obtained from plant raw materials. Plant-derived resins are produced without relying on petroleum resources, the plant as a raw material absorbs carbon dioxide and grows, and even when discarded by incineration, the combustion calories are generally small and generated CO _2. It is attracting attention as an environmentally friendly resin due to its small amount. Plant-derived resins are generally biodegradable, but are not necessarily biodegradable from the standpoint of preventing the exhaustion of petroleum resources. That is, the resin that contributes to environmental protection includes a plant-derived resin that does not have biodegradability in addition to the biodegradable resin. Hereinafter, these resins are collectively referred to as “environmental resins”.

Currently used as environmental resins are polylactic acid (hereinafter sometimes abbreviated as “PLA”), PBS (polybutylene succinate (copolymer resin of 1,4 butanediol and succinic acid)). And PET system (modified polyethylene terephthalate).

Of these resins, PLA can be produced by chemical synthesis using sugar produced by plants such as corn or sweet potato as a raw material, and has the potential for industrial production. Plastics containing such plant-derived resins are also called bioplastics. PLA has attracted particular attention since mass production using corn as a raw material has started, and it is desired to develop a technology that can apply PLA to a wide variety of uses as well as uses that require biodegradability. Yes.

As a method for improving the characteristics of such environmental resin, a method of blending other components has been proposed. For example, Patent Document 1 proposes that about 0.5 to 20 wt% of synthetic mica is added to PLA in order to improve the heat resistance of PLA.

In addition, there is an example of reporting the possibility of application to a PC exterior by blending kenaf fiber with PLA (Serizawa et al., “Development of kenaf fiber reinforced polylactic acid” (14th Annual Meeting of the Japan Society for Plastic Molding Processing) Proceedings of the Conference Lecture, pages 161-162, 2003 (Non-Patent Document 1)) Specifically, after forming a PLA resin compounded with kenaf fiber, adding an annealing process will increase the heat resistance of the PLA resin. It has been reported that the possibility of applying PLA to a PC exterior body is increased.

Japanese Patent Laid-Open No. 2002-173583

In addition to physical properties such as impact resistance and heat resistance, design effects are also required for exterior bodies of electrical equipment. However, the resin composition using PLA is easily restricted in terms of moldability and mechanical properties. Therefore, in an exterior body formed by molding PLA without emphasizing the design effect, for example, without filling with a flame retardant component and a filler for increasing the strength, desired mechanical properties may not be obtained. is there. The present invention has been made in view of such a current situation, uses environmental resins such as polylactic acid and / or lactic acid copolymer, and can recycle resources by recycling, and exhibits an excellent design effect. An object is to provide an exterior body of an electric device.

The present invention
A base material comprising a resin composition containing a resin component containing 50% by weight or more of polylactic acid and / or lactic acid copolymer;
A decorative sheet provided with a decorative layer on one surface of a sheet made of a resin composition containing a resin component containing 50% by weight or more of polylactic acid and / or lactic acid copolymer,
An exterior body, wherein the decorative sheet is attached to the base material so that the surface of the base material and the surface of the decorative sheet provided with the decorative layer are opposed to each other. provide.

The present invention also provides:
A substrate comprising a resin composition containing a resin component containing 50 wt% or more of polylactic acid and / or lactic acid copolymer, and a resin composition containing a resin component containing 50 wt% or more of polylactic acid and / or lactic acid copolymer A decorative sheet provided with a decorative layer on one surface of the sheet, and the surface of the substrate and the surface provided with the decorative layer of the decorative sheet are opposed to each other. It is a manufacturing method of the exterior object by which the sheet for decorating is pasted on the substrate, and when the sheet for decorating is pasted on the substrate, of the resin composition which constitutes the sheet for decorating Provided is a method for producing an exterior body, characterized by heating to a temperature higher than the glass transition point.

In the exterior body of the present invention, appearance defects such as welds, color streaks, and color unevenness occur in a base material injection molded using a resin composition containing polylactic acid and / or a lactic acid copolymer as a main component. Even so, the decorative sheet attached to the substrate (that is, laminated) exhibits a design effect. Therefore, the mechanical strength necessary for the exterior body can be secured by the base material without considering the influence of the appearance of the base material on the design of the exterior body. In addition, since both the base material and the decorative sheet are made of a resin composition containing polylactic acid and / or a lactic acid copolymer as a main component, the exterior body can be recycled without separating and separating the two. It becomes possible.

The front view which shows the external appearance of the liquid crystal display device as an example of the electric equipment by one embodiment of this invention The perspective view which shows the state which removed the stand in the liquid crystal display device shown in FIG. The block diagram which shows the circuit block of the whole structure of the liquid crystal display device shown in FIG. The top view which removes a back cabinet in order to demonstrate the example of arrangement | positioning of the circuit block of the liquid crystal display device shown in FIG. Sectional drawing which shows an example of the exterior body by this invention Sectional drawing which shows the state of the middle stage which manufactures the exterior body by this invention Sectional drawing which shows the method to manufacture the exterior body of this invention typically

Hereinafter, embodiments of an exterior body of an electric device according to the present invention will be described with reference to the drawings.

FIG. 1 and FIG. 2 are a front view and a perspective view, respectively, showing an external appearance of a liquid crystal display device as an example of an electric apparatus according to an embodiment of the present invention. FIG. 3 is a block diagram showing a circuit block of the entire configuration of the liquid crystal display device, and FIG. 4 is a plan view showing the circuit block of the liquid crystal display device with the back cabinet removed in order to explain an arrangement example of the circuit block.

As shown in FIGS. 1 and 2, the liquid crystal display device has a display device main body 1 and a stand 2 that holds the display device main body 1 in an upright state. The display device body 1 includes a display module including a liquid crystal display panel 3 which is a flat display panel and a backlight device (not shown in FIGS. 1 and 2) in an exterior body 5 made of a resin molded product. It is configured by housing. The exterior body 5 includes a front cabinet 6 provided with an opening 6 a and a back cabinet 7 combined with the front cabinet 6 so as to correspond to the image display area of the liquid crystal display panel 3. Reference numeral 6b denotes a speaker grill for releasing the sound of the speaker to the outside.

As shown in FIGS. 3 and 4, the schematic configuration of the entire liquid crystal display device is a signal including a driving circuit for displaying an image on the liquid crystal display panel 3 and a lighting control circuit for controlling lighting of the backlight device 4. A processing circuit block 8, a power supply block 9 for supplying a power supply voltage to the liquid crystal display panel 3, the backlight device 4 and the signal processing circuit block 8, and a television broadcast received and received by the signal processing circuit block 8. This is a configuration having a tuner 10 for supplying a signal and a speaker 11 for outputting sound. The signal processing circuit block 8 and the power supply block 9 are both configured by mounting components constituting a circuit on a circuit board. The circuit board on which the signal processing circuit block 8, the power supply block 9, the tuner 10, and the like are mounted is attached so as to be disposed in a space between the back surface of the backlight device 4 and the back cabinet 7.

In FIG. 3, the speaker is omitted. In FIG. 4, reference numeral 12 denotes an external signal input terminal for inputting a video signal from an external device such as a DVD player to the liquid crystal display device, and is mounted on the signal processing circuit block 8.

FIG. 5 is a cross-sectional view showing the main structure of the front cabinet 6 in the exterior body 5 according to the present invention, and FIG. 6 is a cross-sectional view showing a state in the middle of manufacturing the front cabinet 6.

As shown in FIGS. 5 and 6, the front cabinet 6 includes a base material 13 and a decorative sheet 14. The base material 13 is produced by molding a resin composition containing a resin component mainly composed of polylactic acid and / or a lactic acid copolymer. The decorative sheet 14 is produced by molding a resin composition containing a resin component mainly composed of polylactic acid and / or a lactic acid copolymer into a sheet shape, and a decorative layer is provided on one surface. ing. The front cabinet 6 attaches the decorating sheet 14 to the surface of the base material 13 in a state where the surface of the base material 13 and the surface of the decorating sheet 14 provided with the decorating layer are opposed to each other so as to be in close contact with each other. It is constituted by. In the illustrated form, the base material 13 and the decorative sheet 14 are integrated by an adhesive layer 16.

The polylactic acid constituting the substrate 13 and the decorative sheet 14 is, for example, poly-L-lactic acid composed of L-lactic acid units, poly-D-lactic acid composed of D-lactic acid units, poly-L-lactic acid and It may be a mixture containing a polylactic acid stereocomplex formed by mixing poly-D-lactic acid, or a polylactic acid block copolymer obtained by solid-phase polymerization of this mixture. The lactic acid copolymer is, for example, L-lactide and / or D-lactide starting from L-lactic acid and / or D-lactic acid, oxyacid, lactone, dicarboxylic acid, or It is a copolymer obtained by copolymerizing a polyhydric alcohol (for example, caprolactone or glycolic acid).

The base 13 contains a resin composition containing polylactic acid and / or lactic acid copolymer as a main component, that is, polylactic acid and / or lactic acid copolymer at 50 wt% or more, desirably 70 wt% or more. The polylactic acid and / or lactic acid copolymer contained in the resin component may be unused or may be regenerated from a used product recovered from the market (recycled resin). Unused resin and recycled resin are provided, for example, in the form of pellets. Unused resin pellets and recycled resin pellets may be mixed and used. Alternatively, the polylactic acid and / or lactic acid copolymer contained in the resin component is derived from milled pellets obtained by pulverizing and repelling molded mills such as spools and runners generated when the base material 13 is injection molded. It may be a thing. The end material pellets may be used by mixing with unused resin pellets and / or recycled resin pellets.

The mixing ratio of these pellets may be such that the unused resin pellets are 40 wt% to 70 wt%, the recycled resin pellets are 25 wt% to 50 wt%, and the end material pellets are 5 wt% to 10 wt%.

Here, an example of the composition of the unused resin pellets is as follows.
70 wt% to 80 wt% of polylactic acid and / or lactic acid copolymer polymerized by polymerizing L-form or D-form lactic acid produced by fermenting starch
Crystal nucleating agents such as calcium carbonate, trimesic acid triamide compound and copper phthalocyanine 1 wt% to 3 wt%,
Impact resistance improver such as ABS, butadiene, silicone rubber 5wt%,
Fillers for increasing mechanical strength such as talc and silica 5wt% -10wt%,
Wet heat modifiers such as carbodiimide 3wt%-5wt%
3 wt% to 5 wt% plasticizer such as phthalate ester,
Release agents such as silicone compounds, fluorine compounds, zinc stearate 1wt% -3wt%,
Inflammability imparting component that imparts flame retardancy 1wt% to 5wt%,
Other organic and inorganic materials such as fillers.

Recycled resin pellets are obtained by separating resin components containing polylactic acid and / or lactic acid copolymer from used products collected from the market, and pulverizing them to 2 mm to 3 mm with a crusher to re-pelletize them. The polylactic acid recycled resin pellets preferably have the same material composition as the unused pellets. However, recycled resin pellets are resin components containing polylactic acid and / or lactic acid copolymers contained in used products collected from the market, and differ in the content of components and components from unused pellets. There are many cases. On the other hand, the base material 13 needs to have physical properties that can withstand actual use of an electric device incorporated as an exterior body. Therefore, according to the physical property of the pellet of the recycled resin collect | recovered from a market, the compounding ratio of the said unused pellet and the compounding rate of the said additive added to a resin component are adjusted. Thereby, the physical property value of the resin composition constituting the substrate 13 is set to a value necessary for ensuring predetermined characteristics.

When the base material 13 is used as an exterior body of an electric device, an example of physical property values required for the resin component constituting the base material 13 is as follows.

(Characteristics of resin as an exterior body of electrical equipment)
Tensile strength: 30 MPa or more Bending strength: 50 MPa or more Tensile breaking elongation: 10% or more Flexural modulus: 2000 MPa or more Charpy impact strength: 5 kJ / m ² or more Ball pressure temperature: 80 ° C. or more Vicat softening temperature: 90 ° C. or more (Flame resistance): UL standard V1 or higher Hydrolysis resistance: 60 ° C, 90% RH, 70% or more of initial mechanical strength at 500 hours. It is measured based on JIS standards using a sample of length × width × thickness of 80 mm × 10 mm × 4 mm molded at a temperature of 185 ° C., a mold temperature of 100 ° C. and a cooling time of 60 seconds.

The base material 13 is selected from unused polylactic acid and / or lactic acid copolymer pellets, recycled resin pellets collected from the market, milled and re-pelletized mill pellets, or these pellets. A mixture of two or more pellets is formed and manufactured. Specifically, the base material 13 can be obtained by heating the pellets to a temperature of 170 ° C. to 240 ° C. in an injection molding machine and filling the pellets in a mold having a temperature of 70 ° C. to 110 ° C.

Here, the flame retardant component that can be contained in the resin composition will be described. “Flame retardant” refers to the property that combustion is not continued or no residue is produced after the ignition source is removed. Here, the “flame retardancy imparting component” that imparts flame retardancy is a component that makes the resin flame retardant by adding it. In the outer package of the present invention, it is preferable that silica-magnesia catalyst particles are contained as a flame retardant component. The silica-magnesia catalyst is a catalyst used in the purification, decomposition, synthesis and / or reforming of hydrocarbons, and is a catalyst in the form of a compound which does not contain any halogen or hardly generates dioxin. In the exterior body of the present invention, the catalyst as the flame retardancy imparting component is kneaded with the resin component in advance and dispersed in the resin component, so that the resin component actually burns during the combustion reaction. It has an action specific to the catalyst. This catalytic action greatly contributes to the flame retardancy of the resin.

When the silica-magnesia catalyst particles are subjected to a high temperature (for example, about 500 ° C. or more) during combustion, the polymer, which is a resin component, is cleaved from the end and decomposed into low molecular weight molecules. If the molecular weight of the molecule after being decomposed is small, the total molecular weight of the combustible gas that is thermally decomposed and ejected is reduced, and thus it is considered that the flame retardancy of the resin composition is achieved.

Generally, in the combustion of a resin, the energy generated when the molecules generated by the thermal decomposition of the resin during combustion burn is supplied to the resin as radiant heat, and the resin is further thermally decomposed. It continues with the combustion cycle of burning. If the molecular weight of the molecules generated by the decomposition of the resin is higher, and therefore more gas as fuel is supplied, the combustion energy becomes higher. In addition, as the combustion energy increases, the radiant heat in the combustion field increases and the resin combustion continues for a longer time.

Therefore, when the resin is cut the same number of times, it is preferable that the resin is decomposed into molecules having a smaller molecular weight in terms of reducing combustion energy and suppressing thermal decomposition of the resin. The silica-magnesia catalyst particles are considered to have a catalytic action so as to decompose the resin into smaller molecular weight molecules during the combustion of the resin. Such a flame retardant mechanism is different from that of halogen flame retardants and phosphorus flame retardants. For example, in a halogen flame retardant represented by bromine, a halogen gas component decomposed by heat traps radicals ejected from a resin in a gas phase, and suppresses a combustion reaction. It is said that the phosphorus-based flame retardant promotes the generation of a carbonized layer (char) by combustion, and this carbonized layer blocks oxygen and radiant heat and suppresses combustion.

In the present invention, it is preferable to use silica-magnesia catalyst particles having an average particle size of 10 μm or less. An average particle diameter is a particle diameter of the median diameter D50 calculated | required from the particle size measured by the laser diffraction scattering method. When the average particle diameter of the silica-magnesia catalyst particles is 10 μm or less, an outer package having good flame retardancy can be obtained. As the average particle size of the silica-magnesia catalyst particles is smaller, an outer package having higher flame retardancy can be obtained with the same content. Therefore, as the average particle diameter of the silica-magnesia catalyst particles is smaller, an outer package having a desired flame retardancy (for example, UL94 standard V0 grade) can be obtained even if the content of the silica-magnesia catalyst particles is reduced. be able to.

Silica-magnesia catalyst particles having an average particle size of 10 μm or less, for example, 1 μm or more and 10 μm or less can be obtained by pulverizing silica-magnesia catalyst particles having a large particle size. The pulverization may be performed using, for example, a jet mill.

The filler for increasing the strength that can be contained in the resin composition serves to improve the mechanical strength, for example, the tensile strength and / or the bending strength of the resin composition by adding it. The filler for increasing the strength is a fibrous or plate-like substance made of glass or an inorganic substance (for example, metal oxide, mineral, etc.). Silica-magnesia catalyst particles as a flame retardant imparting component are distinguished from fillers in that even when added, the bending strength of the resin composition is not improved.

Next, the decorative sheet 14 will be described.

The decorative sheet 14 has a resin composition containing polylactic acid and / or lactic acid copolymer as a main component, that is, a resin component containing polylactic acid and / or lactic acid copolymer at 50 wt% or more, desirably 85 wt% or more. The resin composition is extruded into a sheet having a thickness of 150 μm to 300 μm and has light transmittance.

In this decorative sheet 14, a decorative layer 15 having a thickness of 5 μm to 20 μm having a decorative portion 15a is formed on one surface (the surface facing the base material 13) by silk screen printing or gravure printing. Is formed. The ink used for printing is produced, for example, by blending 3 wt% to 6 wt% of a pigment of a predetermined color and 30 wt% to 40 wt% of a solvent in a resin containing 50 wt% to 60 wt% or more of polylactic acid. Further, an adhesive layer 16 for joining the decorating sheet 14 to the base material 13 is formed on the decorating layer 15. The adhesive layer 16 is made of, for example, a two-component curable adhesive composed of an epoxidized polyolefin or an aliphatic diene polymer that is compatible with polylactic acid or a lactic acid copolymer. The thickness of the adhesive layer 16 may be 3 μm to 10 μm, for example.

An example of the composition of the resin composition constituting the decorative sheet 14 is as follows.
85 wt% to 95 wt% of polylactic acid polymerized by polymerizing L-form or D-form lactic acid produced by fermenting starch,
Crystal nucleating agents such as calcium carbonate, trimesic acid triamide compound and copper phthalocyanine 1 wt% to 3 wt%,
Surface lubricants such as oleic acid amide and fluorine compounds 1wt% -3wt%,
Wet heat modifiers such as carbodiimide 1wt% -3wt%,
3 wt% to 5 wt% plasticizer such as phthalate ester,
Release agents such as silicone compounds, fluorine compounds and zinc stearate 1 wt% to 3 wt%,
About 1 wt% of antistatic agents such as alkyl sulfates
UV absorbers such as phenyl salicylate, about 1 wt%,
Other organic and inorganic materials such as fillers.

In addition, it is preferable that this sheet | seat 14 for decorating is what was produced without attaching | subjecting to an extending process (non-stretched film). The decorating sheet 14, which is an unstretched sheet, can stretch by about 200% when stuck to the base material 13 in a heat-softened state by a method described later, and therefore closely follows the shape of the base material 13. Further, the polylactic acid and / or lactic acid copolymer contained in the resin composition constituting the decorative sheet 14 is preferably in an amorphous state before being attached to the base material 13, and is attached to the base material 13. After that, it is configured to crystallize. Since the non-crystallized polylactic acid is inferior in heat resistance, if the decorative sheet containing the non-crystallized polylactic acid is located on the surface of the exterior body, the commercial value of the exterior body itself may be lowered.

The decorative sheet 14 covers at least a part of the surface of the substrate 13 and gives a desired design effect to the covered part. Therefore, even when the resin composition constituting the base material 13 includes a filler for increasing strength, for example, and the molding surface cannot be a glossy surface, it is high by appropriately selecting the decorative sheet 14. A design surface having a specular glossiness can be realized in the exterior body. For example, the decorative sheet 14 preferably has a gloss with a 20-degree specular gloss (G _S (20 °)) of 60 or more measured according to JIS Z 8741. Such gloss is achieved, for example, by using a resin composition that contains polylactic acid and / or lactic acid copolymer that does not decrease transparency even after crystallization, and preferably does not contain a filler to increase strength. it can.

The specular glossiness (G _S (θ)) (θ is an incident angle) is measured according to JIS Z 8741. Specifically, the specularly reflected light flux φs from the sample surface with respect to the specified incident angle θ (the angle formed by the optical axis of the light receiving system and the normal of the sample surface), and the standard surface with respect to the specified incident angle θ The specular reflection light beam φos is obtained and calculated according to the following formula. In the formula, Gos (θ) is the glossiness of the standard surface used. The standard surface is a glass surface having a refractive index of 1.567.

Next, a method of sticking the decorative sheet 14 to the base material 13 in the method of manufacturing the exterior body of the present invention will be described.

First, as shown in FIG. 6, the decorative sheet 14 is disposed on the base material 13 formed in a predetermined shape so that the adhesive layer 16 faces the base material 13. Thereafter, the decorative sheet 14 is heated by an infrared heater to a temperature higher than the glass transition point of the resin composition, preferably 20 ° C. to 40 ° C. higher than the glass transition point. The resin composition contains a resin component mainly composed of polylactic acid and / or a lactic acid copolymer, and its glass transition point is about 60 ° C. Accordingly, the decorative sheet 14 is preferably heated to about 80 ° C. to about 100 ° C. When the decorative sheet 14 is softened by heating, the decorative sheet 14 is pressed so that the sheet 14 wraps around the entire surface of the base material 13 and bonded to the base material 13 by the adhesive layer 16. In this process, the polylactic acid and / or lactic acid copolymer of the resin composition constituting the decorative sheet 14 is crystallized and changes to a state having predetermined characteristics. Through the above steps, the decorative sheet 14 is attached so as to be in close contact with the surface of the base material 13, thereby obtaining the exterior body of the present invention.

In the step of attaching the decorative sheet 14 to the base material 13, the decorative sheet 14 is preferably heated from the side of the base material 13 and the opposite side so that the heating temperatures on both sides are different. A method for heating the decorative sheet 14 to the base material 13 in such a manner will be described with reference to FIG.

7, the base material 13 is fixed by a jig 112 on a lower table 111 provided in a vacuum / pressure forming machine 110. The decorative sheet 14 is fixed to a frame-shaped upper table 114 that is provided separately from the lower table 111 and has an opening 113 at the center. The decoration sheet 14 is fixed using a tape (not shown) so that the decoration layer 15 is on the lower side so that the entire periphery of the sheet 14 is in close contact with the upper table 114. The upper table 114 is disposed above the lower table 111 so as to face it. The lower table 111 can be moved up and down by an elevating unit 119. By the movement of the lower table 111, the decorative layer 15 of the sheet 14 can be attached to a predetermined position of the base material 13. In addition, the decoration sheet 14 is arranged so that the decoration portion 15 a of the decoration layer 15 is located in the opening 113 of the upper table 113.

The decorative sheet 14 is heated by the upper infrared heater 115 and the lower infrared heater 116 so as to have a temperature higher than the glass transition point Tg of the decorative sheet 14. The upper infrared heater 115 preferably heats the decorative sheet 14 to a temperature of Tg + 15 ° C. to Tg + 20 ° C. (when Tg is 60 ° C., 75 ° C. to 80 ° C.). The decorative sheet 14 is heated to a temperature not lower than normal temperature (25 ° C.) and not higher than Tg. When the back surface of the decorative sheet 14 is excessively heated by the lower infrared heater 116, the sheet 14 may hang down or the characteristics of the base material 13 may be damaged by heat.

When the heated decorative sheet 14 is in a softened state, the lower infrared heater 116 is slid. Then, the lower sealed space 118 between the upper table 111 and the lower table 114 is decompressed using the pump 120. An upper sealed space 117 formed between the upper table 113, the sheet 14, and the wall surface of the molding machine 110 is pressurized using the pump 21. The two sealed spaces 118 and 117 are preferably decompressed and pressurized so that the pressure difference is 0.1 MPa to 0.2 MPa. For example, the lower sealed space 118 is depressurized to about 0.1 MPa (0.1 atm), and the upper sealed space 117 is pressurized to about 20 MPa (20 atm). As a result, the sheet 14 is in close contact with the entire surface of the base material 13 so as to be wound. The sheet 14 and the base material 13 are joined by an adhesive layer (not shown) provided on the surface of the decorative layer 15. In the pasting step including this heating step, the polylactic acid and / or lactic acid copolymer contained in the decorative sheet 14 is crystallized and changes to a state having predetermined characteristics.

As described above, the exterior body of the present invention is excellent in design by covering and decorating the entire surface of the base material 13 with the decoration sheet 14, and is provided as an environment-friendly exterior body. Can do. The reason will be specifically described below.

When a resin composition prepared by blending one or more additives with a resin component mainly composed of polylactic acid and / or lactic acid copolymer, which is a plant-derived resin, is injection-molded, color unevenness, color stripes, Appearance defects such as cloudiness, welds, and sink marks occur. Appearance defects are caused, for example, by the addition of fillers for increasing strength, crystal nucleating agents, flame retardant imparting components, and the like. A molded body in which such an appearance defect has occurred cannot be used as an exterior body of an electrical device even if it satisfies the mechanical characteristics required for the exterior body of the electrical device. By using such a molded body as the base material 13 and pasting the decorative sheet 14 on the base material 13, the exterior body constituted by the base material 13 satisfies the mechanical properties required for the exterior body, The appearance (design) required for the exterior body can be satisfied. The decorative sheet 14 can be configured to conceal the appearance of the base material 13 by appropriately selecting the decorative layer 15 (including the decorative portion 15a). Alternatively, even when no defect occurs in the appearance of the base material 13a, the exterior body can be easily designed without changing the base material 13 by appropriately selecting a decorative layer (including the decorative portion 15a). Can be changed.

Furthermore, both the base material 13 and the decorative sheet 14 are made of a resin composition containing polylactic acid and / or a lactic acid copolymer as a main component. Therefore, when the exterior body composed of these is recovered as waste after use, the exterior body can be directly subjected to a regeneration process and reused as pellets without separating the base material 13 and the decorative sheet 14. In addition, the flame retardant component is blended only in the resin composition constituting the base material 13, and the flame retardant component is not blended in the resin composition constituting the decorative sheet 14. Thus, it is possible to realize an exterior body having flame retardancy without impairing the design. The appearance design can also be ensured by not adding a filler for increasing the strength to the resin composition constituting the decorative sheet 14.

Moreover, in the manufacturing method of the exterior body by this invention, it arrange | positions on the base material 13 which shape | molded the decoration sheet | seat 14 in the predetermined shape, Then, the sheet | seat 14 for decoration is made of the resin composition which comprises it. After heating to a temperature higher than the glass transition point to soften the decorative sheet 14, the decorative sheet 14 is stuck to the surface of the base material 13 by pressing the entire surface of the base material 13. That is, in the method for manufacturing an exterior body according to the present invention, the decorating sheet 14 containing amorphous relatively soft polylactic acid and / or lactic acid copolymer is heated and softened, and is attached to the base material 13. The resin is crystallized. Such a manufacturing method makes it possible to easily attach the decorative sheet 14 to the base material 13 having a complicated shape. Furthermore, the advantage that the heat resistance and rigidity of the sheet 14 are improved is obtained by crystallizing the decorative sheet 14.

In the above embodiment, the example in which the adhesive layer 16 is provided on the decorative sheet 14 and the decorative sheet 14 is joined to the base material 13 by the adhesive layer 16 has been described. In another embodiment, the decorative sheet 14 can be joined to the base material 13 by an insert molding method without using the adhesive layer 16. Specifically, the decorative sheet 14 is heated in advance with a heater to a temperature of 60 ° C. to 80 ° C. higher than the glass transition point to crystallize amorphous polylactic acid. At the same time, by transferring the decorative sheet 14 to the molding die in this state, a preform processed into the shape of the exterior body is formed. Next, in a state where this preform is placed in a mold of an injection molding apparatus for molding the base material 13, the resin composition constituting the base material 13 is filled. Thereby, simultaneously with shaping | molding the base material 13, the sheet | seat 14 for decorating can be stuck, and an exterior body is completed.

Specifically, the exterior body of the present invention includes other display devices (plasma display devices, organic EL display devices, etc.), computers, mobile phones, audio products (for example, radio, cassette decks) in addition to the liquid crystal display device. , CD players, MD players), microphones, keyboards, portable audio players and other electrical equipment exterior bodies, and electrical parts exterior bodies. Electrical equipment is not limited to household use. Electrical equipment includes industrial and medical equipment.

The exterior body according to the present invention is useful for providing an exterior body for an electrical device that uses an environmental resin such as polylactic acid and / or a lactic acid copolymer and is capable of recycling resources by recycling.

DESCRIPTION OF SYMBOLS 1 Display apparatus main body 5 Exterior body 6 Front cabinet 13 Base material 14 Decorating sheet 15 Decorating layer 15a Decorating part 16 Adhesive layer 110 Vacuum / pressure forming machine 111 Lower table 112 Jig 113 Opening part 114 Upper table 115 Upper part Heater 116 Vacuum / Pneumatic molding machine 117 Lower closed space 118 Upper closed space 119 Lifting unit 120 Pressure pump 121 Pressure reduction pump

Claims (9)

1. A base material comprising a resin composition containing a resin component containing 50% by weight or more of polylactic acid and / or lactic acid copolymer;
   A decorative sheet provided with a decorative layer on one surface of a sheet made of a resin composition containing a resin component containing 50% by weight or more of polylactic acid and / or lactic acid copolymer,
   The decoration sheet is affixed to the substrate such that the surface of the substrate and the surface of the decoration sheet provided with the decoration layer are opposed to each other. Equipment exterior.
2. The exterior body of an electric device according to claim 1, wherein the resin composition further contains a flame retardant component and a filler for increasing strength.
3. 3. The exterior body of an electric device according to claim 2, wherein the flame retardancy imparting component is silica-magnesia catalyst particles.
4. 2. The decorative sheet has light permeability, and the resin composition constituting the decorative sheet does not contain a filler for increasing strength and a flame retardancy imparting component. 4. An exterior body of an electric device according to any one of items 1 to 3.
5. The decorative sheet is 20 degree specular gloss is measured in accordance with _{JIS Z 8741 (G S (20} °)) has a glossy surface is 60 or more, according to any one of claims 1 to 4, Exterior body of electrical equipment.
6. 6. The electric device according to claim 1, wherein the polylactic acid and / or lactic acid copolymer contained in the resin composition is contained in a recycled resin. Exterior body.
7. The exterior body for an electric device according to any one of claims 1 to 6, wherein the sheet is configured to conceal the surface appearance of the base material by the decorative layer.
8. Resin composition containing a resin component containing 50 wt% or more of polylactic acid and / or lactic acid copolymer on a base material comprising a resin composition containing 50 wt% or more of polylactic acid and / or lactic acid copolymer A decorative sheet provided with a decorative layer on one surface of the sheet, and the surface of the substrate and the surface provided with the decorative layer of the decorative sheet are opposed to each other. A method for manufacturing an exterior body of an electric device to which the decorative sheet is attached,
   When the decorative sheet is attached to the base material, the decorative sheet is heated to a temperature higher than the glass transition point of the resin composition constituting the decorative sheet. A method for manufacturing an exterior body of a device.
9. The exterior of claim 8, wherein the heating of the decorative sheet is performed such that the polylactic acid and / or lactic acid copolymer of the resin composition constituting the decorative sheet is crystallized. Body manufacturing method.

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