JP2013247105A - Casing for straight-tube type cold-cathode tube lighting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-weight metal-resin composite compound molding or a casing in which metal excellent in heat radiation and a resin composition having both of transparency and flame retardancy are used, and further provide a casing for a straight-tube type CCFL lighting excellent in waterproofness.SOLUTION: A metal-resin composite compound molding, in which an aluminum alloy sheet and polycarbonate resin are insert-molded with an average thickness of 0.2 to 2.0 mm at an aluminum part, 0.5 to 3 mm at a polycarbonate part, and a flame retardancy satisfying specifications of UL94 VO, is used as a casing for straight-tube type CCFL lighting. The aluminum alloy sheet of a visible-light highly reflecting type having 99% or more of a pure aluminum composition is used so as to attain further downsizing without using a conventional reflection plate inside a casing.

Description

The present invention relates to a metal / resin composition composite molded article that is lightweight, has both heat dissipation, high transparency, and flame retardancy. A metal / resin composition composite molded product, preferably a composite molded product integrally molded using an insert molding method.
The present invention also relates to a case for a straight tube type cold cathode tube (hereinafter referred to as CCFL) lighting device that replaces a conventional fluorescent lamp.

In order to preserve the global environment, energy saving and reduction of greenhouse gases are considered as challenges, but in the field of lighting, in recent years, LED fluorescent tubes and CCFLs have become prominent.

As such a straight tube type lighting housing material, there is a material using a composite molded product made of metal and transparent resin (Patent Document 1), but it is difficult to waterproof due to the fitting between the molded product and the molded product. There are still challenges for outdoor use.
Similarly, although there is a transparent casing made of a hollow and transparent cylindrical body manufactured by a hollow resin extrusion (Patent Document 2), it lacks the function of a heat sink that dissipates the heat generated by the CCFL. Remains.

Furthermore, the weight of the straight-tube CCFL illumination currently on the market is 1.2 to 1.4 times that of the same type of LED illumination, and a reduction in weight is required.
The cross section of the conventional straight tube type CCFL illumination is provided with a metal light reflection plate in addition to the metal part of the housing for 360 degree light distribution. For this reason, compared with a straight tube type LED lighting apparatus, the same type CCFL lighting apparatus cannot avoid an increase in weight.

Patent No. 48347792 JP2008-251231

The objective of this invention is providing the housing | casing for straight tube | pipe type CCFL lighting which has a light weight, heat dissipation, and a flame retardance using the metal and resin composition composite molded product.
A further object of the present invention is to provide a straight tube type CCFL lighting housing having a reflective function on a metal housing portion.

In view of the above problems, the metal / resin composition composite molded product of the present invention is characterized by being formed by integrally molding a lightweight, heat-dissipating metal material and a highly transparent and flame-retardant resin composition. And
More preferably, it is a metal / resin composition molded product integrated by an insert molding method.
Further, the metal part is a surface having a reflection function.

The metal used in the present invention preferably has the following characteristics. As the metal, it is desirable to use an aluminum alloy that is lightweight and has high thermal conductivity. More preferred is an aluminum alloy having an alloy number in the 1000s, and even more preferred are 1050, 1070, 1080.

The thickness of the metal is preferably 0.2 to 2.0 mm, more preferably 1.0 to 2.0 mm, which satisfies the balance of the housing strength and heat dissipation, particularly the heat transport ability that is an index of heat dissipation. More preferably, it is 0.3 to 0.6 mm for realizing weight reduction.

The resin composition used in the present invention preferably has the following characteristics. Resin compositions include polyolefins and copolymers thereof (polyethylene, polypropylene, polymethylpentene) polymethacrylic acids and copolymers thereof, polyesters and copolymers thereof (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate) polystyrene And copolymers thereof, aromatic polyamides and copolymers thereof, polycarbonates and copolymers thereof, norbornenes (cycloolefin polymers, cycloolefin copolymers) polysulfones and copolymers thereof.

The thickness of the resin composition is preferably 0.5 mm to 3.0 mm from the viewpoint of housing strength and transparency, and is further preferably 1.0 to 3.0 mm, more preferably 1.0 to 3.0 mm, considering flame retardancy. 2.0 mm.

As described above, since the CCFL is a linear light source, the diffusivity is generally not important for the casing, and it needs to be highly transparent.
In this case, the total light transmittance of the resin composition is desirably 85% or more, more preferably 88% or more.
However, diffusivity may be required depending on the purpose and application of the straight tube CCFL illumination.
In this case, a light diffusion grade resin is used.

As for the flame retardancy of the resin composition, it is desirable to satisfy the V-0 grade according to UL94 standard which is an index of flame retardancy. The UL standard is a standard that is determined by the Underwriters Laboratories of the United States and evaluated by the company, and is a general index. Generally, it is a test in which a flame is applied to a test piece defined in UL-94 to check the combustion time and the presence or absence of dripping.

This molding method will be described below.
The metal sheet set in the feeding machine is fed out and passed through a forming machine which is a roll bending process, so that it becomes semicircular and is sent to a crosshead die (metal / resin composite mold).
On the other hand, in a state where the resin composition is melted from the extruder, the resin composition is sent to the crosshead die disposed at the tip of the extruder and melted and adhered to the semicircular metal sheet in the crosshead die.
More specifically, the crosshead die is designed so that the outer diameter of the resin side is concentric with the semicircular metal sheet, and is bonded and fixed at an integrated location, with a semicircular resin at the top and a semicircle at the bottom. A composite pipe to which a shape metal sheet is bonded and fixed is continuously formed.
So-called insert molding is performed in which the resin composition and the tip of the semicircular metal sheet are melted and adhered in a crosshead die and continuously extruded.
In addition, the outer diameter is regulated while cooling in the vacuum sizing process, completely cooled and solidified in a cooling water tank, bonded and fixed, taken up by a multi-roll type take-up machine, and fixed length by a cutting machine The metal / resin composite molded product of the present invention is cut.
The aluminum alloy wheel 6, which will be described in more detail with reference to FIG. 3, becomes a semicircular metal base material that can be hollow-formed by the homing machine 7.
On the other hand, the polycarbonate resin is extruded in a molten state by the extruder 8 and melt-molded with the semi-circular aluminum sheet by the crosshead die 9 to be integrated into a hollow pipe shape.
Further, the outer diameter is regulated while cooling in the sizing step 10, and it is completely cooled and solidified in the cooling water tank 11.
Then, it is taken up by the take-up machine 12 and cut into a fixed length by the cutting machine 13 to obtain a metal / resin composition composite molded product formed by insert-molding the aluminum alloy sheet of the present invention and a polycarbonate resin.
The arrows (→) shown in the figure indicate the direction of flow of the aluminum alloy plate and the polycarbonate resin.

More specifically, the screw for making the resin extrusion speed per unit time at the time of insert molding and the metal feeding speed uniform, and making the melt extrusion amount of the resin composition at the time of insert molding constant. Design is required. Furthermore, it is necessary to design a mold for melting and adhering a metal and a resin. Further, a sizing / water tank design for maintaining a predetermined shape is also required in the cooling process.

The metal / resin composition composite molded product of the present invention is a one-dimensional hollow molded product, and its cross-section has a combined structure of two layers of a metal layer and a resin composition, and the molded metal and resin composition are It is integrated.
If the adhesive strength of the composite part of metal and resin is further required, (1) roughen the surface of the aluminum to improve the adhesiveness (2) apply the adhesive metal to the cross die head and send it to the cross die head (3) There are measures such as injecting an adhesive into a predetermined position in the cross die head.

The straight tube type CCFL lighting housing of the present invention uses a metal / resin composition composite molded product as a heat radiating housing, and the CCFL distributes light by 360 ° on the inner surface of the housing. In addition, it is important that the CCFL fluorescence is highly reflected on the metal surface and the reflected light is efficiently used on the resin side.
For that purpose, it is desirable to select an aluminum alloy sheet having an alloy number of 1000s (1000 to 1100), which is a pure aluminum alloy having a pure aluminum content of 99%.
It is desirable that the reflectivity has a reflectivity of 88% or more with visible light having a wavelength of 500 nanometers. The reflectivity is measured according to JIS-D5705 with an incident angle of incident light of 25 degrees.

The metal / resin composition composite molded product of the present invention is an excellent lightweight molded product, has heat dissipation, high transparency, and flame retardancy, and warps using the metal / resin composition composite molded product. It is possible to provide a heat radiating housing without any problem, and it can be preferably used for a straight tube type CCFL lighting housing. Further, the metal / resin composition composite molded product integrally molded by the insert molding method has a waterproof performance, and can be manufactured at a lower cost and lighter than the conventional manufacturing method.
Furthermore, by making the CCFL fluorescent light, which is distributed by 360 °, highly reflective on the inner surface of the metal casing, a straight tube CCFL lighting casing can be obtained without using a conventional reflector.

Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited thereby.

Aluminum sheet (Alloy No. 1070 manufactured by Daiwa Metal Industry Co., Ltd.) 0.5 mm thick, 35.4 mm wide, and polycarbonate resin (Panlite MN-4805Z, manufactured by Teijin Chemicals Ltd.) are used for insert molding. A hollow pipe of the metal / resin composition was obtained.
As shown in FIG. 1 (cross-sectional view), sufficient sealing properties were secured by insert molding of a metal and a resin composition.
The thickness of the polycarbonate resin part was 1.5 mm, and the joint part with aluminum was 2.0 mm in total thickness.
The CCFL mount 2 capable of mechanically fixing the CCFL fluorescent tube is supported by sockets at both ends of the straight tube.
The length of the CCFL lighting straight tube case is 1200 mm, and the CCFL fluorescent tube 1 is Sanken Electric Co., Ltd. Sanken: SS40J Tube diameter 4.0φmm Thickness 0.5mm, Length 1150mm 2 lamps (Power consumption 28W, 2 lamp intervals Is 20 mm).
Power supply wiring such as a ballast was provided so that it could be lit at AC100V.
A cradle was placed at the center of the CCFL, and the CFL fluorescent tube was held by a holding piece 5 having a width of 5 mm shown in FIG. 2 at a pitch of 200 mm.
Furthermore, both ends were sealed with PBT (polybutylene terephthalate) caps, and a straight tube for CCFL lighting was used in which a metal / resin composition composite molded product was used for the casing.

Comparative example

As shown in FIG. 4, an aluminum sheet (alloy No. 1070 manufactured by Daiwa Metal Industry Co., Ltd.) is used with a thickness of 1.0 mm, a width of 35.4 mm, and a polycarbonate resin (Panlite MN-4805Z, manufactured by Teijin Chemicals Ltd.). A metal / resin composition composite molded product that can be easily combined was prepared as a case for a straight tube type CCFL lighting.

The following tests were carried out and evaluated for Examples and Comparative Examples.
(1) Dimension measurement The flat plate thickness was measured with an electronic micro film thickness meter manufactured by Anritsu Corporation.
The curved surface thickness was measured with an ultrasonic thickness meter manufactured by Olympus.
(2) Total light transmittance Nippon Denshoku Industries Co., Ltd. turbidimeter NDH-2000 type was used. The measurement was performed in the state of a flat plate.
(3) Flame retardant grade The flame retardant standard of UL94 was adopted from the characteristic table of the light diffusion flame retardant grade of resin manufacturers. However, the thickness of the resin composition is within the standard condition range.
(4) A test (waterproof test) against water intrusion of a water-sensitive metal / resin composition composite molded article. Mount the water sensitive test paper “TeeJet” of Spraying Systems Japan Co., Ltd. in three places of the straight pipe (76mm x 26mm x 3 sheets), seal both ends of the straight pipe, and place the straight pipe on the turntable Water of 10 liters / minute was sprinkled from a watering nozzle for 5 minutes. Evaluation was made based on the change in color of the water sensitive paper. If it feels water, it will turn blue. The water sensitivity was used as an index of waterproofness.

As a result of Table 1, the straight tube type CCF lighting using the metal / resin composition composite molded product of the example for the casing can be reduced in weight, and waterproofness is recognized.
Although the lighting state is a visual judgment, there is no uneven reflection, uneven brightness, etc., and uniform illumination is obtained.

The metal / resin composition composite molded product of the present invention is particularly useful as a casing of a straight-tube CCFL lighting device, has both transparency, heat dissipation, and flame retardancy, and is lightweight and waterproof. Widely used as a casing for straight tube CCFL lighting such as washrooms, halls, outdoor lighting, signboards, etc.

It is an integrated sectional view by the insert molding method. FIG. It is an insert molding process drawing. It is a metal / resin composition fitting method / cross-sectional view

1. CCFL (Cold Cathode Tube)
2. CCFL mount 3. Aluminum alloy4. 4. Polycarbonate resin CCFL holding piece6. 6. Aluminum alloy wheel Homing machine 8. Polycarbonate extruder9. Crosshead die 10. Sizing unit 11. Cooling water tank 12. Take-up machine 13. Cutting machine 14. Fitting location 15. Composite part

Claims (3)

It is a metal / resin composition composite molded product formed by insert molding of an aluminum alloy sheet and a polycarbonate resin. The average thickness is 0.2 to 2.0 mm for the aluminum portion and 0.5 to 3 mm for the polycarbonate portion. A casing for illuminating a straight tube type cold cathode tube. The metal / resin composition composite molded article according to claim 1, wherein the polycarbonate resin satisfies the flame retardancy standard UL94 V0. 2. The straight tube type cold cathode tube illumination housing according to claim 1, wherein the aluminum alloy sheet has a pure aluminum component of 99% or more.

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