JP2002211679A - Antistatic tray - Google Patents

Abstract

(57) [Problem] To provide a deep drawn plastic tray having good conductivity, and having transparency and antistatic effect. An antistatic layer (12) containing tin oxide having a needle-like crystal structure doped with antimony oxide is provided on both surfaces of a thermoplastic plastic sheet (11). A drawing process was performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antistatic tray used for transferring electronic components such as IC chips and diodes.

[0002]

2. Description of the Related Art Conventionally, electronic parts have been housed and transferred in plastic trays formed by deep drawing. However, plastic trays are easily charged with static electricity, and dust adheres to them.Therefore, the performance of components stored during the transfer of electronic components may deteriorate, or the performance may be impaired by contamination by dust or dirt during use. Was.

In order to provide an antistatic effect, a plastic tray in which conductive carbon is kneaded into plastic has been developed. However, there is a problem that the plastic tray is colored and lacks transparency.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has been made by a deep drawing process which has good conductivity, transparency and antistatic effect. It is an object of the present invention to provide a plastic tray.

[0005]

According to the first aspect of the present invention, an antistatic layer containing tin oxide having a needle-like crystal structure doped with antimony oxide is provided on both surfaces of a thermoplastic plastic sheet. An antistatic tray, wherein the thermoplastic plastic sheet is subjected to a deep drawing process.

As described above, since the antistatic layer containing tin oxide having a needle-like crystal structure doped with antimony oxide is provided on both surfaces of the thermoplastic plastic sheet,
The tray formed by deep drawing has an antistatic effect, and the generation of static electricity is extremely reduced. In particular, even when the antistatic layer is extended by the deep drawing process, the antistatic layer has a needle-like crystal structure, and the overlap between the needles is not cut, so that the deterioration of the antistatic performance is small.

According to a second aspect of the present invention, in the first aspect of the present invention, the antistatic layer is a needle-like layer obtained by doping the antimony oxide with respect to 100 parts by weight of a thermoplastic resin capable of following deep drawing. Crystal structure tin oxide 50 ~
An antistatic tray comprising a layer containing 400 parts by weight.

As described above, since the antistatic layer is made of tin oxide having a needle-like crystal structure doped with antimony oxide, a stable antistatic effect can be obtained and transparency can be enhanced.

[0009] The invention of claim 3 is based on claim 1 or 2.
In the invention, the tin oxide having a needle-like crystal structure has a major axis diameter in a length direction of 0.1 to 3.0 μm, a minor axis diameter in a width direction of 0.005 to 0.03 μm, and a major axis diameter. And a ratio of the short axis diameter to the short axis diameter is 20/1 to 30/1.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An antistatic tray according to the present invention will be described in detail below based on one embodiment. As shown in FIG. 1, for example, the antistatic tray (10) of the present invention comprises an antistatic layer (12) containing tin oxide having a needle-like crystal structure doped with antimony oxide on both surfaces of a thermoplastic sheet (11). ), And then the thermoplastic plastic sheet is subjected to deep drawing.

As the thermoplastic plastic sheet (11), a non-stretched polyethylene terephthalate resin (A-PET), a polyethylene terephthalate (PET) resin which can be subjected to a deep drawing process, and 1,4-cyclohexanedimethanol, isophthalic acid or the like. A generally known plastic sheet formed from a resin (PET-G), a polystyrene resin, a polycarbonate resin, a polyvinyl chloride resin, a polypropylene resin, or the like obtained by copolymerizing a copolymer component such as neopentyl glycol at about 20 to 35%. Can be used. The thickness of the sheet is 200 to 1500 μm.
Of these can be preferably used.

The antistatic layer (12) comprises a thermoplastic resin as a binder and an antistatic agent. The thermoplastic resin must be a resin that can follow the deep drawing process of the thermoplastic plastic sheet (11).
Urethane resins can be preferably used. As the antistatic agent, tin oxide having a needle-like crystal structure doped with antimony oxide can be suitably used in terms of antistatic effect, transparency, and the like.

The mixing ratio of the thermoplastic resin to the antistatic agent is 50 to 4 parts by weight based on 100 parts by weight of the thermoplastic resin.
Preferably it is 00 parts by weight.

In addition, tin oxide having a needle-like crystal structure doped with antimony oxide has a major axis diameter in the longitudinal direction of 0.1 to 0.1 mm.
3.0 μm, short axis diameter in the width direction is 0.005 to 0.03 μm
m, the ratio of the major axis diameter to the minor axis diameter is preferably 10/1 to 40/1.

In forming the antistatic layer (12) on the thermoplastic plastic sheet (11), a generally known coating method such as a gravure coating method or a roll coating method can be employed. The coating thickness is 0.1
It is preferable that the thickness be about 5.0 μm (dry).

The thermoplastic sheet thus formed on which an antistatic layer is formed is finally formed into a tray by a generally known sheet forming method such as a vacuum forming method, a pressure forming method, etc. Use a prevention tray.

The resulting antistatic tray had a total light transmittance indicating transparency of 80% or more and a surface resistance value indicating an antistatic effect of 10 ⁵ to 10 ¹⁰ Ω.

[0018]

The present invention will be described in detail with reference to the following examples. Example 1 An A-PET sheet having a thickness of 700 μm was prepared as a thermoplastic plastic sheet (11).

Separately, as an antistatic agent for forming the antistatic layer (12), the major axis diameter in the longitudinal direction is 0.2 to 2.
Preparation of tin oxide having a needle-like crystal structure doped with antimony oxide having a short axis diameter of 0.01 to 0.02 μm in a width direction of 0.01 to 0.02 μm and a ratio of a long axis diameter to a short axis diameter of 20/1 to 30/1. did. As a thermoplastic resin serving as a binder of an antistatic agent, a polyester-based resin (water dispersion, solid content: 30%) was prepared as a main component.

The above-mentioned antistatic agent and a polyester resin liquid as a binder are mixed in a solid content ratio of 2/1 (200/10
0), and the solid content is 30%.
Was prepared.

This coating solution is coated with 700 μm thick A-PET.
1 μm thick by gravure coating method on both sides of sheet
(Dry) to form an antistatic layer (12).

From the sheet provided with the antistatic layer,
A tray having a size of 0 cm, a width of 10 cm, and a height of 3 cm was prepared by a vacuum molding method, and was used as an antistatic tray of Example 1.

Example 2 The antistatic tray of Example 2 was prepared using the same materials and method as in Example 1 except that the mixing ratio of the antistatic agent and the polyester resin was changed to 4/1 (400/100). And

Example 3 The antistatic tray of Example 3 was prepared using the same materials and method as in Example 1 except that the mixing ratio of the antistatic agent and the polyester resin was set to 1/2 (50/100). And

Comparative Example 1 The antistatic tray of Comparative Example 1 was prepared using the same material and method as in Example 1 except that the mixing ratio of the antistatic agent and the polyester resin was 2/5 (40/100). And

The total light transmittance and surface resistance of the bottom portion of the three types of antistatic trays and the surface resistance value of the narrowed portion of the three types of antistatic trays manufactured in this way were determined by the following methods. It was measured. Table 1 shows the results. Total light transmittance measurement method ‥ Haze meter SZ-Σ80
(Manufactured by Nippon Denshoku Industries Co., Ltd.) Surface resistance measurement method ‥ High resistance meter Hiresta IP
(MCP-HT260), (Mitsubishi Chemical Corporation), H
Measured with A probe

[0027]

[Table 1]

As described above, in the first to third embodiments which are within the scope of the present invention, the surface resistance value is 10
^Although an antistatic effect of ¹¹ Ω / cm ² or less was obtained and the antistatic effect was maintained, in Comparative Example 1, the amount of the antistatic agent was too small to maintain the antistatic function after drawing.

[0029]

As described above, since the antistatic tray of the present invention uses tin oxide having a needle-like crystal structure, transparency can be obtained. For this reason, it is possible to check stored items from the outside, which was not possible with a tray using conventional conductive carbon. Further, since the antistatic layer has a needle-like crystal structure, even when the antistatic layer is extended by molding, the antistatic agents keep contact with each other, and the surface resistance value of the narrowed portion is less reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view showing an embodiment of an antistatic tray according to the present invention.

[Explanation of symbols]

 10 Antistatic tray 11 Thermoplastic sheet 12 Antistatic layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08J 7/04 CEZ H01B 5/14 Z // H01B 5/00 C08L 101: 00 5/14 B65D 85/38 S C08L 101: 00 1/00 BF term (reference) 3E033 AA10 BA13 BA16 BA18 BA19 BA22 BA26 BB04 BB08 CA17 DA08 DD01 FA01 FA04 GA03 3E096 BA08 CA06 EA11X FA07 GA01 4F006 AA12 AA15 AA17 AA35 AA36 AB35 A37A04 A37A04 AA28C AA29A AA29C AK01A AK01B AK01C AK41 AK42 BA03 BA06 BA10A BA10C CA22A CA22C DA01 DE01 EJ01A EJ01C GB16 GB48 JA20A JA20C JB16A JB16B JB16C JB20A JB20C JG02 YY00G YA00 GBY

Claims (3)

[Claims] An antistatic layer containing tin oxide having a needle-like crystal structure doped with antimony oxide is provided on both surfaces of a thermoplastic plastic sheet, and then the thermoplastic plastic sheet is subjected to a deep drawing process. An antistatic tray characterized by the following: 2. The antistatic layer according to claim 1, wherein said antimony oxide-doped tin oxide having a needle crystal structure is added to 50 parts by weight of a thermoplastic resin capable of following deep drawing.
The antistatic tray according to claim 1, comprising a layer contained in an amount of from 400 to 400 parts by weight. 3. The tin oxide having a needle-like crystal structure has a major axis in a length direction of 0.1 to 3.0 μm and a minor axis in a width direction of 0.1 μm.
005 to 0.03 μm, and the ratio of the major axis diameter to the minor axis diameter is 1
The antistatic tray according to claim 1 or 2, wherein the ratio is 0/1 to 40/1.