JP3543938B2 - Liquid crystal display element transport tray - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquid crystal display element transport tray that accommodates and transports liquid crystal display elements. INDUSTRIAL APPLICABILITY The tray of the present invention has a small powder drop due to contact with the liquid crystal display element, and is excellent in the performance of protecting the liquid crystal display element from destruction due to external impact and electrical failure due to generation of static electricity.
[0002]
[Prior art]
A display device using a liquid crystal is widely used in all fields such as a controller for a personal computer and a television, a car navigation system, and the like. Until the final assembly, the liquid crystal display element must be stored so as not to be damaged by vibration, impact, and the like, and must be safely transported as necessary.
[0003]
[Problems to be solved by the invention]
The present invention provides a liquid crystal display element transport tray suitable for storing, storing, and transporting the liquid crystal display element.
[0004]
[Means for Solving the Problems]
That is, the present invention relates to a transport tray for a liquid crystal display element, which is made of a foam of a thermoplastic resin composition, has a surface resistance of less than 10 ¹² Ω / □, and a density of 140 to 800 kgm ^−3. This is a display element transport tray. In order to facilitate storage, storage, and transport, the tray has a pocket portion for placing a liquid crystal display element and a support section for supporting the liquid crystal display element. Further, this tray is a liquid crystal display element transport tray having a buffering property capable of reducing the occurrence of powder dropping and the contamination of parts due to contact with the liquid crystal display element and preventing the destruction of parts due to impact.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail. The foam of the thermoplastic resin composition is used for the substrate of the tray of the present invention. As the thermoplastic resin, a polypropylene resin or a polyester resin is preferable.
[0006]
As the polypropylene-based resin, those having a melt index of 3 g / 10 minutes or less are preferable in order to obtain a good foam, such as a propylene-based homopolymer, a propylene-ethylene copolymer, and a propylene-ethylene-diene copolymer. A polymer mainly composed of polypropylene is used. The melting point of propylene homopolymer is 176 ° C., and the melting point of the copolymer is 135 ° C. to 160 ° C. In order to obtain a foam having excellent heat resistance, it is desirable to use one having a high melting point. In addition, a resin having good miscibility such as another polypropylene or an ethylene-vinyl acetate copolymer may be mixed with a polypropylene-based resin as a main component.
[0007]
As the polyester resin, polyethylene terephthalate, polybutylene terephthalate, polybutylene terephthalate elastomer, amorphous polyester, polycyclohexane terephthalate, etc., and these resins alone or a mixture of a plurality of these resins may be used. A modified resin containing 50% by weight or more of these resins is used.
[0008]
Further, when a polyester resin is used as the thermoplastic resin in order to obtain a good foam, it is preferable to add a melt modifier. Examples of the melt modifier include acid anhydrides, such as pyromellitic anhydride, benzophenonetetracarboxylic anhydride, ethylene glycol bis (anhydrotrimellitate), and glycerol tris (anhydrotrimellitate). And the like.
[0009]
The surface resistance of the tray of the present invention must be less than 10 ¹² Ω / □. When the surface resistance value is 10 ¹² Ω / □ or more, static electricity is generated due to the charging of the foam surface, and the dust adheres to the foam, making it unsuitable as a package for electronic components. Further, the charged static electricity causes a situation in which these parts and devices lose their functions, which is not preferable.
[0010]
In order to reduce the surface resistance, for example, a thermoplastic resin composition in which an antistatic agent is mixed with a thermoplastic resin is preferably used. As the antistatic agent, a polyetheresteramide resin is preferable. The polyetheresteramide resin has a melting point of 180 to 210 ° C. and a solution viscosity obtained by measuring a formic acid solution (0.5 g / 100 ml) at 25 ° C. with a ubbelohde viscometer (viscosity constant 0.0314). Of 1.6 to 2.2 ηSP / C is used. The amount of the polyetheresteramide resin used is 5 to 30 parts by weight, preferably 7 to 20 parts by weight, based on 100 parts by weight of the thermoplastic resin. When the amount is less than 5 parts by weight, the surface resistance of the obtained foam is higher than 10 ¹² Ω / □, and when the amount exceeds 30 parts by weight, the miscibility with the thermoplastic resin of the base material is poor. As a result, bleed-out occurs from the surface of the foam, and the mold and the electronic components to be packaged are not preferable.
[0011]
A compatibilizer may be used to uniformly disperse the antistatic agent in the base thermoplastic resin in order to make the antistatic performance of the tray surface uniform.
[0012]
The foam of the present invention can be produced by extrusion foaming the above resin composition. The method of mixing the thermoplastic resin and the antistatic agent is not particularly limited, but a method of directly charging the raw material mixed and stirred into the extruder at the time of foam molding, the raw material mixed and mixed into a single-screw or twin-screw extruder. Any of the methods used for melt extrusion, pelletization, and foam extrusion can be used.
[0013]
In the case of using a pyrolytic foaming agent, the resin composition obtained by the above method is mixed with a foaming agent, and if necessary, an appropriate amount of a crosslinking agent, a foaming aid, a filler, a content, etc. You may mix.
[0014]
The mixture thus obtained is melt-kneaded in an extruder and extruded and foamed to produce a desired foam. The production method is selected from either injection molding or vacuum molding of a sheet-like foam. The extrusion temperature at this time is not particularly limited, but conditions suitable for foaming may be set by the thermoplastic resin as the base material.
[0015]
Examples of the foaming agent used for foaming include volatile foaming agents such as propane, butane, and pentane and mixtures thereof, organic foaming agents such as azodicarbonamide, dinitrosopentanemethylenetetraamine, sodium bicarbonate, and citric acid. Or a combination of an organic acid or a salt thereof with a bicarbonate, or the like can be suitably used. Further, carbon dioxide, nitrogen, water and the like can also be used.
[0016]
The density of the foam is 140～800Kgm ^-3, is less than 140Kgm ^-3 reduces the rigidity of the foam, there would be no function as a packaging member. When the density of the foam is higher than 800 kgm ⁻³ , the cushioning property is reduced, and the function of preventing the liquid crystal display element from being destroyed by an external impact is lost. The expansion ratio is preferably 1.8 to 5 times.
[0017]
As the shape of the tray, a tray having a pocket portion for placing a liquid crystal display element and a supporting portion for supporting the liquid crystal display element is preferable.
[0018]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples.
[0019]
(Example 1)
As the thermoplastic resin, the density 900Kgm ^-3, melt flow rate 3.0 g / min and a crystalline polypropylene 70% by weight and density 900Kgm ^-3, melt flow rate 3.0 g / min, using a capillograph manufactured by Toyo Seiki Co. 30% by weight of a polypropylene having a measured melt tension of 16.6g (manufactured by Montelusque Sunrise Co., Ltd., PF-814) and 15 parts by weight of an antistatic agent (AE-506, manufactured by Arakawa Chemical Co., Ltd.), and further as a foaming agent 4 parts by weight of a pyrolytic foaming agent (manufactured by Clariant: CF40E) were mixed with a tumbler mixer, and the mixture was mixed with a single screw extruder (diameter: 65 mm, L / D: 32, circular mold diameter: 100 mm, (Circular mold lip gap: 0.6 mm) and melt-kneaded at an extrusion temperature of 210 ° C. The sheet was extruded from (a) into the air at a low pressure to obtain a sheet-like foam molded article.
[0020]
The thickness of the foam sheet as the obtained foam was 1.0 mm and the density was 300 kgm- ³ . The foam sheet had a surface resistance of 3.43 × 10 ¹⁰ Ω / □. The surface resistance value was measured one minute after contacting the measurement terminal with the foam at an applied voltage of 500 V using "Hiresta-UP, MCP-HT450, J box U type" manufactured by Mitsubishi Chemical Corporation. It is a numerical value.
[0021]
The surface of the foam was rubbed 150 times with a glass piece at a corner of 90 ° at a speed of 30 reciprocations / minute, and the generation of shavings was examined. No shavings were found. When the obtained foam was molded into a tray having the shape shown in FIGS. 1 and 2 and the liquid crystal display element was placed and actually transported, there was no damage and no generation of shavings was observed.
[0022]
(Example 2)
100% by weight of a polyethylene terephthalate resin having a density of 1.15 (manufactured by Eastman Kodak Company, PET10388) as a thermoplastic resin, 0.5 part by weight of talc as a cell regulator, and 0.1% of pyromellitic anhydride as a melt viscosity modifier 3 parts by weight, 15 parts by weight of the same antistatic agent as in Example 1, and 5.5 parts by weight of the pyrolytic foaming agent were mixed, and were extruded in the same extruder as in Example 1 at an extrusion temperature of 285 ° C. to form a sheet. Was obtained.
[0023]
The thickness of the foam sheet as the obtained foam was 0.85 mm, and the density was 400 kgm- ³ . The foam sheet had a surface resistance of 4.48 × 10 ¹⁰ Ω / □. Furthermore, when the generation of shavings was examined in the same manner as in Example 1 by using a glass piece on the foam surface at a corner portion having an angle of 90 °, no shavings were found.
[0024]
【The invention's effect】
The package of the present invention has a surface resistance value that exhibits antistatic properties, generates less shavings due to abrasion of the tray surface, and has a cushioning property when used as a package because it is a foam. As a result, the mesa glass package protects the components from electrical disturbances, does not cause powder contamination due to friction at the contact points with the mesa glass, and further prevents the mesa glass from being impacted. It has the characteristic of having a buffering property that can prevent the destruction of the material. Therefore, it is suitable as a mesa glass package for a liquid crystal display and a package for other electronic components, and is industrially useful.
[Brief description of the drawings]
Fig. 1 Side view of tray. Fig. 2 Top view of tray.

Claims (4)

Polypropylene resin composition containing an antistatic agent or consist foam of polyester resin composition, the surface resistance of 10 ¹² Ω / □ less, Ri density 140～800Kgm ^-3 der, put the liquid crystal display device A liquid crystal device transport tray having a pocket portion and a support portion for supporting the liquid crystal display device . 2. The tray according to claim 1, wherein the antistatic agent is a polyetheresteramide resin. The tray for transporting a liquid crystal element according to claim 1, obtained by injection molding or vacuum molding of a sheet-like foam. A liquid crystal element carrying tray according to any one of claims 1 to 3, wherein the dusting less from the tray surface by contact with the liquid crystal display device.

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