JP2010214628A - Composite hollow pipe and method for manufacturing the same - Google Patents

Abstract

The present invention provides a composite hollow pipe having both light transmittance and thermal conductivity (heat dissipation), which is useful as a housing for LED lighting devices that are widely used due to its excellent energy efficiency and color rendering. To do.
A one-dimensional hollow pipe having a similar cross-sectional shape, a light-transmitting resin layer 8 made of a resin or resin composition having a light transmittance of 35% or more, and a heat of 2 W / m · K or more. The composite hollow pipe comprised combining the heat conductive resin layer 9 which consists of a resin composition which has conductivity.
[Selection] Figure 3

Description

  The present invention relates to a composite hollow pipe having both light transmittance and heat conductivity (heat dissipation), which is particularly useful as a housing of an LED lighting device, and a manufacturing method thereof.

  In recent years, LED lighting has been widely used because of its excellent energy efficiency and color rendering. However, since LED light is generally in the form of a point light source, some light control is often required when used as illumination. For example, by combining with optical elements such as prisms and lenses, light directivity and light condensing can be controlled, and by combining optical elements with light diffusivity, control of angular distribution of emitted light intensity and point light source Can be converted into a surface light source (diffusion or disappearance of light spots).

  For example, when trying to create an LED lighting device similar to the shape of a conventional fluorescent lamp that emits light by utilizing a discharge phenomenon in an inert gas and the light emitting surface continuously extends in one direction, A structure is used in which an LED mounting substrate mounted in a one-dimensional array is used, the LED mounting substrate is disposed in the center, and the periphery thereof is covered with a light-transmitting hollow pipe. Such a structure is characterized in that it is similar in the cross-sectional direction.

  By the way, in LED elements, especially LED elements with a large light output, it is often necessary to take measures to dissipate heat in order to exhibit the performance of the elements. The heat dissipation measure refers to a technical measure for dissipating the heat spot generated by the heat generation of the LED element by thermally diffusing and dissipating the generated heat amount outside the apparatus.

  This is because the performance (brightness, lifetime, etc.) of the LED element is limited by the temperature rise due to heat generation of the LED element. That is, the brightness and life of the LED element greatly depend on how efficiently the heat dissipation measures are taken.

  There are various heat dissipation measures in the LED lighting device, but the heat dissipation portion is formed of a heat conductive metal material such as an aluminum alloy or a magnesium alloy (see, for example, Patent Documents 1 and 2), and the LED substrate 3 and the support. In the meantime, a sheet in which a heat conductive sheet made of a heat conductive resin is interposed is proposed (for example, Patent Document 3).

  In this way, for LED lighting devices in which the light emitting surface is continuous in one direction, a substrate in which a metal plate with high thermal conductivity such as aluminum is stacked on the LED mounting substrate is used, and this LED mounting substrate is arranged at the center. In some cases, a structure in which the periphery is covered with a light-transmitting hollow pipe (hereinafter referred to as structure example A) is used. (An example is shown in FIG. 1)

  As another example of heat dissipation measures, a structure in which a pedestal portion made of a metal material having high thermal conductivity is provided on the back surface of the LED mounting substrate, and this pedestal portion also serves as a housing of the LED lighting device (hereinafter, referred to as “LED illuminator”) In some cases, it is referred to as Structural Example B). (An example is shown in FIG. 2)

JP 2006-339653 A JP 2008-243498 A JP 2008-287994 A

In the structural example A, the heat generation (heat spot) of the LED element is thermally diffused over the entire mounting substrate, and the temperature of the LED element can be reduced to some extent, but an air layer with extremely low thermal conductivity is interposed. Furthermore, since the ability to dissipate heat from the mounting substrate to the hollow pipe and the illumination device is low, it is not sufficient as a heat dissipation measure.
Further, when the hollow pipe is made of a highly transparent resin material, the rigidity tends to be insufficient, and particularly when an illuminating device exceeding 1 m is produced, there is a case where bending deformation occurs due to the weight of the illuminating device.

  In the structural example B, the heat generated by the LED element can be efficiently dissipated to the outside of the lighting device through the metal base portion having high thermal conductivity, and the rigidity of the lighting device can be ensured. Since the specific gravity of the metal pedestal is high, the overall weight of the lighting device is significantly increased. For this reason, there exists a problem that the handling property of an illuminating device and the safety | security at the time of apparatus fall are inferior. Furthermore, since a resin pipe and a metal pedestal are used in combination, stress distortion may occur due to differences in thermal expansion coefficient, moisture absorption rate, etc. at the joint, causing damage or joining. There is also a problem that a gap is formed in the part, and moisture enters from there to adversely affect the LED lighting device.

  That is, the present invention is a one-dimensional hollow pipe having a similar cross-sectional shape, a light-transmitting resin layer made of a resin or a resin composition having a light transmittance of 35% or more, and a heat conduction of 2 W / m · K or more. It is a composite hollow pipe comprised combining the heat conductive resin layer which consists of a resin composition which has a rate. Among these, preferably, in the outer peripheral surface of the composite hollow pipe, 40 to 80% of the surface area is composed of a light-transmitting resin layer and 20 to 60% of the surface area is a thermally conductive resin layer with respect to the total surface area of the outer peripheral surface. The composite hollow pipe configured to include at least, or the outer peripheral surface of the composite hollow pipe is configured with a light-transmitting resin layer, and the area of 20 to 60% of the outer peripheral surface is configured with a heat conductive resin layer on the inner periphery. It is a composite hollow pipe. Moreover, this invention is a manufacturing method of this composite hollow pipe, and is an LED lighting apparatus using this composite hollow pipe.

  Since the composite hollow pipe of the present invention is a composite hollow pipe having two functions of light diffusion and heat dissipation, for example, when used as a housing and pedestal of an illumination device using an LED array, control of LED illumination light and LED Device heat dissipation is possible at the same time. Further, since the flexural modulus of the heat conductive resin layer is very high and the specific gravity is small, the rigidity of the entire composite hollow pipe is increased. For example, even when the composite hollow pipe is formed to have a length of 1 m or more, It is possible to obtain a high-quality composite hollow pipe or an LED lighting device that can suppress bending deformation due to its own weight, and is excellent in safety when the lighting device is dropped, etc., and excellent in waterproofness.

It is a schematic diagram which shows an example (structure example A) of the cross-section of the conventional LED lighting apparatus. It is a schematic diagram which shows another example (structure example B) of the cross-section of the conventional LED lighting apparatus. It is an example of the cross-sectional shape of the composite hollow pipe of this invention. It is another example of the cross-sectional shape of the composite hollow pipe of this invention. It is another example of the cross-sectional shape of the composite hollow pipe of this invention. It is another example of the cross-sectional shape of the composite hollow pipe of this invention. It is another example of the cross-sectional shape of the composite hollow pipe of this invention. It is another example of the cross-sectional shape of the composite hollow pipe of this invention. It is another example of the cross-sectional shape of the composite hollow pipe of this invention. It is another example of the cross-sectional shape of the composite hollow pipe of this invention. It is another example of the cross-sectional shape of the composite hollow pipe of this invention. It is another example of the cross-sectional shape of the composite hollow pipe of this invention. It is an example regarding the guide shape for mounting board fixation. It is an example regarding the guide shape for heat conductive resin layer fixation. It is an example of the cross-sectional structure of the LED lighting apparatus using the composite hollow pipe of this invention. It is another example of the cross-sectional structure of the LED lighting apparatus using the composite hollow pipe of this invention. It is another example of the cross-sectional structure of the LED lighting apparatus using the composite hollow pipe of this invention. It is another example of the cross-sectional structure of the LED lighting apparatus using the composite hollow pipe of this invention. It is an example of the cross-sectional structure of the pipe length direction of the LED lighting apparatus using the composite hollow pipe of this invention. It is a cross-sectional schematic diagram which shows an example of the sealing structure of a composite hollow pipe edge part. It is explanatory drawing regarding the measurement of the dispersion degree of a light transmissive resin layer. It is a schematic diagram which shows an example of arrangement | positioning of a two-color extrusion molding apparatus regarding manufacture of the composite hollow pipe of this invention.

Hereinafter, embodiments of the present invention will be sequentially described.
[Structure of composite hollow pipe]
The composite hollow pipe of the present invention is a one-dimensional hollow pipe having a similar cross-sectional shape. When the cross-section is viewed, a shape formed by combining two layers of a light transmissive resin layer and a heat conductive resin layer is formed. is doing. Here, the one-dimensional hollow pipe having a similar cross-sectional shape has the same basic cross-sectional structure, and is discontinuous in the length direction, and has an attachment portion such as a guide shape or a slat. It is a hollow pipe including the case where it has.

  The thickness of the composite hollow pipe is not particularly limited. For example, when it is used as a housing of an LED lighting device, it depends on the size of the light source such as an internal LED and the appearance specification as the lighting device, but for example, a pipe having a circular cross section. In this case, the diameter is generally about 15 to 45 mm.

Similarly, the length of the composite hollow pipe is not particularly limited. For example, as an example of the case where the composite hollow pipe is used as a housing of the LED lighting device, FIG. 19 illustrates a cross-sectional structure in the pipe length direction of the LED lighting device using the composite hollow pipe. Thus, the length of the composite hollow pipe can be appropriately selected according to the purpose of use. Here, it is preferable to keep the length of the composite hollow pipe so as not to be bent and deformed by its own weight, but specifically, it is generally about 100 to 2500 mm.
The cross-sectional shape is not particularly limited, and various shapes such as a perfect circle, an ellipse, a square, a rectangle, a rhombus, a polygon, and the like can be taken.

  For example, when a light source such as an LED is arranged inside a hollow pipe, the light transmissive resin layer serves as a cover for protecting the devices inside the LED and transmits light emitted from the light source. , Play the role of emitting to the outside of the pipe.

  The average thickness of the light-transmitting resin layer is preferably 0.5 to 5 mm, more preferably 1 to 3 mm. If it is less than 0.5 mm, the mechanical strength tends to be insufficient, and if it exceeds 5 mm, the light transmission loss increases, and an increase in pipe weight cannot be ignored.

  The light-transmitting resin layer is made of a resin or a resin composition having a light transmittance of at least 35% or more for the above-mentioned purpose of use. The light transmittance is more preferably 45% or more, still more preferably 55% or more, and most preferably 65% or more. Here, the light transmissive resin layer may be a resin alone or a resin composition in which various additives such as a light diffusing filler are mixed with the resin, as long as the light transmittance is 35% or more.

  Here, the light transmittance is a percentage of the amount of light emitted to the opposite surface side of the layer with respect to the light incident perpendicularly to the layer, but the emitted light is totally emitted to the opposite surface side. The light is measured as a light amount obtained by integrating all the light beams having azimuth angles, that is, the light beams having an emission angle of 0 ° to 90 °. Such a measurement can be generally performed by an integrating sphere type light transmittance measuring device.

The light transmittance is the average transmittance of light in the wavelength region to be used. For example, when visible light is to be used, the average transmittance is in the wavelength region of 380 to 780 nm.
The light-transmitting resin layer is more preferably a heat-resistant and low water-absorbing layer from the viewpoint of enabling wide use, and has a heat distortion temperature of 90 ° C. or higher, more preferably 100 ° C. or higher. It is preferable that the layer has a water absorption of 2% or less, more preferably 1% or less.

  The light transmissive resin layer may be a layer having a control function such as light scattering, diffusivity, refraction, and light condensing according to the purpose of use. These functions include a method of dispersing a filler that imparts such an optical function inside the light-transmitting resin layer, and a concave shape and / or a convex shape (units of several μm to several mm) for imparting such an optical function (lens, And a method of shaping the surface shape of the light-transmitting resin layer.

As for the latter molding method, a method in which a shape corresponding to a mold for molding a light-transmitting resin layer is previously engraved and a shape is automatically given at the time of molding is preferable. Depending on the case, as a post-processing after molding, the optically transmissive resin layer is processed by engraving the shape, the optical resin layer is formed on the light transmissive resin layer by coating, or printed in a pattern. These shapes and functions may be imparted by a method such as.
Details regarding the composition of the light transmissive resin layer will be described later.

The heat conductive resin layer is a layer responsible for the function of transporting toward the outer peripheral surface of the hollow pipe while widely diffusing the heat generated by the light source when a light source such as an LED is disposed inside the hollow pipe, for example. The layer has a characteristic of extremely high thermal conductivity compared to a general resin layer.
The thermally conductive resin layer is a layer having a high thermal conductivity by including a thermally conductive filler in the layer. However, the thermal conductivity of the layer is 2 W / in at least one direction in the layer. The layer having m · K or more, more preferably 4 W / m · K or more, further preferably 6 W / m · K or more, and most preferably 8 W / m · K or more.

The average thickness of the heat conductive resin layer is preferably 1 to 30 mm, more preferably 1.5 to 20 mm, and still more preferably 2 to 10 mm. If the thickness is less than 1 mm, heat diffusion, transport capability, and mechanical strength tend to be insufficient. On the other hand, if it exceeds 30 mm, an increase in the weight of the entire pipe cannot be ignored, which is not preferable.
The specific gravity of the heat conductive resin layer is at least 2.0 g / cm ³ or less, more preferably 1.9 g / cm ³ or less, more preferably 1.8 g / cm ³ or less, from the viewpoint of reducing the weight of the composite hollow pipe. Most preferably, it is 1.7 g / cm ³ or less.

The heat conductive resin layer is preferably a layer having a flexural modulus of 5 GPa or more, more preferably 7 GPa or more, and even more preferably 9 GPa or more, from the viewpoint of increasing the overall rigidity of the composite hollow pipe.
The heat conductive resin layer is more preferably a heat-resistant and low water-absorbing layer from the viewpoint of enabling wide use, and has a heat distortion temperature of 90 ° C. or higher, more preferably 100 ° C. or higher. It is preferable that the layer has a water absorption of 2% or less, more preferably 1% or less.

You may arrange | position the layer which consists of resin of a different kind from resin which forms a heat conductive resin layer in the outer peripheral surface side of a heat conductive resin layer. The purpose of providing this layer is to mechanically protect the surface of the heat conductive resin layer or to improve the assemblability when used as a lighting device. In that case, the average thickness of the layer is preferably about 0.03 to 3 mm. This layer is formed by means such as formation by resin melt molding, integral formation as a resin film for insert molding, or lamination by resin coating. In particular, in the case of forming by resin melt molding, the light transmissive resin layer can be used as it is.
Details of the composition of the heat conductive resin layer will be described later.

Now, the light transmissive resin layer and the heat conductive resin layer in the present invention are combined at an appropriate ratio in the cross section of the composite hollow pipe.
The light-transmitting resin layer preferably occupies 40 to 80% of the surface area with respect to the total surface area of the outer peripheral surface of the composite hollow pipe for the purpose of emitting light from the light source as effectively as possible and in a wide range.
On the other hand, the heat conductive resin layer preferably occupies a surface area of 20 to 60% with respect to the total surface area of the outer peripheral surface of the composite hollow pipe for the purpose of diffusing the heat generated by the light source as widely as possible.

In addition, since the cross-sectional shape of the composite hollow pipe of this invention is similar, the area ratio of an outer peripheral surface is calculated | required from ratio of the length in the outer periphery of each layer in sectional drawing.
As a specific example of this embodiment, in the cross-sectional structure of the composite hollow pipe, a combination structure as illustrated in FIGS.

  Further, a surface layer (hereinafter referred to as a surface layer) made of a resin different from the heat conductive resin layer may be provided on the outer surface and / or the inner surface of the heat conductive resin layer. The surface layer is provided for the purpose of improving the mechanical strength, impact strength, drop impact resistance, wear resistance, surface scratch resistance, designability, designability, decoration, and electrical insulation of the pipe.

The average thickness of the surface layer is preferably in the range of 0.03 to 3 mm. If the average thickness is less than 0.03 mm, it will be insufficient in realizing these purposes, and if it exceeds 3 mm, the heat dissipation performance of the heat conductive resin layer will be deteriorated and the weight of the pipe will be significantly increased. This is not preferable because it causes problems.
Although there is no restriction | limiting in particular about the heat conductivity of a surface layer, From a viewpoint of not having a remarkable bad influence on the heat dissipation of a heat conductive resin layer, More preferably, it is 0.5 W / m * K or more, More preferably, it is 1 W / M · K or more.

These surface layers can be formed by techniques such as resin coatings such as UV curable resins, resin layer coating with heat shrinkable tubes, insert molding of thermoplastic films, and two-color molding of thermoplastic resins (injection molding, extrusion molding). Is possible.
In addition, when using a two-color molding method, the structure which used the light-transmitting resin layer in this invention as it is as a surface layer is also possible, and it is illustrated preferably. In the case of this structure, the outer peripheral surface of the composite hollow pipe is preferably composed of a light transmissive resin layer, and the area of the outer peripheral surface of 20 to 60% is preferably configured to have a heat conductive resin layer on the inner periphery. As a specific example of this aspect, in the cross-sectional structure of the composite hollow pipe, a combination structure as illustrated in FIGS. The heat conductive resin layer on the inner periphery may be solid as illustrated in FIGS. 8 and 9 or may be hollow as illustrated in FIG.

  Here, the light-transmitting resin layer and the heat conductive resin layer may be disposed in contact with each other through an adhesive means such as an adhesive, a pressure-sensitive adhesive, an adhesive sheet, and a pressure-sensitive adhesive sheet. In this case, the light-transmitting resin layer and the heat conductive resin layer are separately molded, and both are engaged and integrated, or one layer is inserted into the other layer and integrated, etc. A composite hollow pipe structure can be obtained.

The interface between the light transmitting resin layer and the heat conductive resin layer may be integrated by fusion bonding, ultrasonic bonding, or the like.
Melt bonding refers to a state in which both resin layers are bonded together in a molten state. It is preferable that the melt bonding is performed collectively at the stage of forming the light transmissive resin layer or the heat conductive resin layer, and generally a so-called two-color molding (injection molding, extrusion molding) technique is used.

  Here, the two-color molding means, for example, that two or more kinds of resin compositions are melted and discharged from a plurality of different resin extrusion nozzles, integrated in a mold and a die, and then cooled and solidified. Is a technique for obtaining a composite molded body of two or more kinds of resin compositions fused and integrated at the interface.

  Each example illustrated in the present invention exemplifies a composite hollow pipe having a substantially circular cross section, but the present invention is not limited to a circular cross section, and in other various cross sectional shapes, Basically, it is possible to design a structure based on the same technical idea as the above example in a circular cross section.

[Disclosure of manufacturing method of composite hollow pipe by two-color molding]
As an example of the manufacturing method of the composite hollow pipe of the present invention, a manufacturing method using a two-color extrusion molding method is illustrated.
The two-color extrusion molding method is a molding method including a step of melting and extruding from a plurality of different extruders, integrating them in one die connected to the plurality of extruders, and then cooling and solidifying. Point to.

  The type of the extruder is, for example, a single-screw full flight or double flight extruder having a diameter of 10 to 90 mm, an extrusion capacity of 0.2 to 100 kg / hr, a temperature riseable temperature of 600 ° C. or less, and a twin-screw extruder rotating in the same direction With a diameter of 10 to 50 mm, extrusion capacity of 0.2 to 100 kg / hr, temperature rise possible temperature of 600 ° C. or less, twin screw extruder different direction rotation, diameter of φ10 to 50 mm, extrusion capacity of 0.2 to 100 kg / hr, temperature increase Possible temperature is 600 ° C. or less. In the present invention, a single-screw full flight extruder is preferably used.

  This is because, in the case of a single-screw extruder, the breakage rate of the short carbon fiber filler can be reduced by being excellent in the ability to adjust the shearing force as low as possible by changing the screw design. At the same time, the heat generation amount of the molten resin can be suppressed, and the thermal deterioration of the resin can be reduced.

  In many cases, it is preferable to use a cylinder and screw of an extruder for extruding the thermoplastic resin composition that have been subjected to surface hardening treatment. The reason for this is that some of the fillers contained in the thermoplastic resin composition have the property of abrading the metal surface, and in long-term molding, the screw and cylinder are worn down to reduce the resin extrusion rate, and the molten resin discharge rate. Reduction in stability, decrease in molten resin temperature stability, decrease in melt resin viscosity, etc. cause deterioration in extruded product quality. This preventive treatment may be mentioned. Examples of the surface hardening treatment include hard chrome plating, nitriding treatment, and various ceramic coatings.

  Examples of the take-up machine include a belt type ring cone motor chain drive take-up machine, a belt type servo motor direct drive take-up machine, a caterpillar type ring cone motor chain drive take-up machine, and a caterpillar type servo motor direct drive take-up machine. In the present invention, a belt type servo motor direct drive type take-up machine is preferably used. The reason for this is that in the case of a belt type servo motor direct drive type take-up machine, the vibration generated by the caterpillar type take-up machine does not adversely affect the appearance of the product. In the case of direct drive of the servo motor, the ratio of the resin extrusion amount by the two extruders can be easily controlled to be constant.

A water tank, a cutting machine, etc. do not choose a model especially, but it is necessary to select the thing suitable for the outer diameter size of a composite hollow pipe.
These facilities are preferably arranged as shown in FIG.
The composite hollow pipe formed in this way can be subjected to heat treatment (annealing) as necessary.

[Detailed disclosure of light-transmitting resin layer]
In the present invention, a thermoplastic resin or a curable resin can be used as the resin used for the matrix of the light transmissive resin layer. However, when it is necessary to ensure moldability and impact resistance, it is often preferable to use a thermoplastic resin.

  Examples of the thermoplastic resin include polyolefins and copolymers thereof (polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyvinyl alcohol, ethylene-vinyl acetate copolymer, ethylene-propylene. Ethylene-α-olefin copolymers such as copolymers), polymethacrylic acids and copolymers thereof (polymethacrylates such as polymethyl methacrylate), polyacrylic acids and copolymers thereof, polyacetals and Copolymers, fluororesins and copolymers thereof (polyvinylidene fluoride, polytetrafluoroethylene, etc.), polyesters and copolymers thereof (polyethylene terephthalate, polybutylene terephthalate, polyethylene 2,6 naphthalate, liquid crystalline poly -), Polystyrenes and copolymers thereof (styrene-acrylonitrile copolymers, ABS resins, etc.), polyacrylonitriles and copolymers thereof, polyphenylene ethers (PPE) and copolymers thereof (modified PPE resins, etc.) Aliphatic polyamides and copolymers thereof, aromatic polyamides and copolymers thereof, polyimides and copolymers thereof, polyamideimides and copolymers thereof, polycarbonates and copolymers thereof, polyphenylene sulfide And copolymers thereof, polysulfones and copolymers thereof, polyether sulfones and copolymers thereof, polyether nitriles and copolymers thereof, polyether ketones and copolymers thereof, polyether ether ketones And copolymers thereof, polyketones and copolymers thereof, Examples include ricone polymers.

  In these thermoplastic resins, for the purpose of improving the flexibility, post-processing property, and handleability, a resin using various elastomer components as a copolymer component as a copolymer component, or a resin different from the matrix in the matrix resin It is also possible to use a resin that is dispersed in a sea-island shape.

  Further, examples of the thermosetting resin include resins having excellent transparency such as acrylics and silicones, and a curable resin in which an elastomer component and a rubber component are copolymerized or dispersed inside the curable resin. Can also be preferably used.

  As the resin used as the matrix of the light-transmitting resin layer of the present invention, a polycarbonate resin, particularly a copolymer polycarbonate containing a copolymer component such as an aromatic polycarbonate or an aliphatic ring is particularly preferably used. The reason for this is that it is excellent in transparency, light transmission, heat resistance and impact resistance and has a low water absorption rate. The polycarbonate resin will be described in detail later.

Now, when giving control functions such as light scattering and light diffusivity to the light transmissive resin layer, the refractive index is different from that of the matrix resin, and the transparent filler is used as the light scattering / light diffusing filler. By mixing, light scattering / light diffusibility can be imparted to the resin layer.
The mixing amount of the filler is determined so as to satisfy the total light transmittance and light scattering / light diffusing property of the resin layer.

  In the present invention, when the light transmissive resin layer is molded into a sheet having a thickness of 3 mm, the light transmittance of the sheet is 35% or more and the degree of dispersion is 20 degrees or more. It is preferable to use a layer. Note that the degree of dispersion means the angle of γ when the amount of transmitted light is 50 when the amount of transmitted light is 100 when γ = 0 ° when a light beam is vertically applied to the surface of the test piece in FIG. .

  Examples of such fillers include silica-alumina clay minerals (hydrous aluminum silicates) represented by kaolin, silica-magnesium clay minerals (hydrous magnesium silicates) represented by talc, inorganic compounds such as calcium carbonate, Fine particles, hollow fine particles, short fibers, cubes made of polymethyl methacrylate resin cross-linked products, silicone resin cross-linked products, metal oxides such as silicon oxide, aluminum oxide and titanium oxide, quartz glass such as aluminum-borosilicate glass, etc. Spindle-like, needle-like, rod-like, plate-like, and irregular-shaped fillers are exemplified. These can be used alone or in combination of two or more. These fillers may be subjected to an appropriate surface treatment for the purpose of enhancing adhesion to the matrix or enhancing durability.

The size of the filler is preferably from 0.1 to 100 μm, more preferably from 1 to 30 μm, as a true spherical particle size. If it is less than 0.1 μm or more than 100 μm, the light diffusibility is insufficient.
Moreover, when it is a short fiber form, it is preferable to satisfy L / D <= 10. Here, L is the average fiber length of short fibers, and D is the average diameter. If the value of L / D is greater than 10, the appearance of the molded product may be deteriorated, or uniform light diffusibility may be lost due to fiber orientation in the molded product, which may be undesirable. The diameter is not particularly limited but is preferably in the range of 3 to 20 μm.

  The mixing ratio of the filler may be in the range of 0.2 to 40% by weight of the entire thermoplastic resin composition, more preferably in the range of 0.5 to 30% by weight, and still more preferably in the range of 1 to 20% by weight. Preferably, if it is less than 0.2% by weight, it is difficult to obtain sufficient light diffusibility, and if it exceeds 40% by weight, the workability and the appearance of the molded product are deteriorated.

  In addition, it is also possible to use an appropriate additive for the light-transmitting resin layer for the purpose of improving the stability and durability of the layer, the purpose of improving the moldability, and the purpose of controlling the light transmission wavelength. More specifically, these additives include known ultraviolet absorbers, infrared absorbers, dyes, pigments, heat stabilizers, antioxidants, mold release agents, plasticizers, flame retardants, and the like.

[Detailed disclosure of heat conductive resin layer]
The thermally conductive resin layer is a layer formed by mixing at least a resin serving as a matrix and a thermally conductive filler. As the resin used as the matrix, a thermoplastic resin or a curable resin can be used. However, when it is necessary to ensure moldability and impact resistance, it is often preferable to use a thermoplastic resin.

  In the present invention, the resin used for the matrix of the heat conductive resin layer is preferably the same type as the resin used for the matrix of the light transmissive resin layer or a resin compatible with each other. As an embodiment of the present invention, when the thermally conductive resin layer and the light transmissive resin layer are integrally molded by a two-color molding method or the like, the adhesive strength of both layers is increased and the molding conditions can be easily set. This is the purpose.

  Examples of the thermoplastic resin include polyolefins and copolymers thereof (polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyvinyl alcohol, ethylene-vinyl acetate copolymer, ethylene-propylene. Ethylene-α-olefin copolymers such as copolymers), polymethacrylic acids and copolymers thereof (polymethacrylates such as polymethyl methacrylate), polyacrylic acids and copolymers thereof, polyacetals and Copolymers, fluororesins and copolymers thereof (polyvinylidene fluoride, polytetrafluoroethylene, etc.), polyesters and copolymers thereof (polyethylene terephthalate, polybutylene terephthalate, polyethylene 2,6 naphthalate, liquid crystalline poly -), Polystyrenes and copolymers thereof (styrene-acrylonitrile copolymers, ABS resins, etc.), polyacrylonitriles and copolymers thereof, polyphenylene ethers (PPE) and copolymers thereof (modified PPE resins, etc.) Aliphatic polyamides and copolymers thereof, aromatic polyamides and copolymers thereof, polyimides and copolymers thereof, polyamideimides and copolymers thereof, polycarbonates and copolymers thereof, polyphenylene sulfide And copolymers thereof, polysulfones and copolymers thereof, polyether sulfones and copolymers thereof, polyether nitriles and copolymers thereof, polyether ketones and copolymers thereof, polyether ether ketones And copolymers thereof, polyketones and copolymers thereof, Examples include ricone polymers.

  These thermoplastic resins are resins that use various elastomer components as soft segments as copolymerization components for the purpose of enhancing their flexibility, post-processing properties, and handling properties, or resins that are different from the matrix in the matrix resin. It is also possible to use a resin that is dispersed in a sea-island shape.

  Examples of curable resins include epoxies, acrylics, urethanes, phenols, silicones, unsaturated polyesters, and other resins. In terms of moldability and heat resistance, epoxies, urethanes, silicones, etc. A thermosetting resin is preferably used, and a curable resin in which an elastomer component and a rubber component are copolymerized or dispersed in the curable resin can also be preferably used.

  The matrix of the heat conductive resin layer of the present invention is preferably a polycarbonate resin, particularly a copolymer polycarbonate containing a copolymer component such as an aromatic polycarbonate or an aliphatic ring. The reason for this is excellent heat resistance and impact resistance and low water absorption.

  In addition, it is also possible to use an appropriate additive for the purpose of increasing the stability and durability of the heat conductive resin layer, the purpose of improving moldability, and the like. More specifically, these additives include known ultraviolet absorbers, infrared absorbers, dyes, pigments, heat stabilizers, antioxidants, mold release agents, plasticizers, flame retardants, and the like.

  Examples of the heat conductive filler include metals such as gold, silver, copper, aluminum, and silicon and alloys thereof, metal oxides such as aluminum oxide, magnesium oxide, silicon oxide, and zinc oxide, aluminum hydroxide, magnesium hydroxide, and the like. Metal hydroxides, metal nitrides such as boron nitride and aluminum nitride, metal oxynitrides such as carbon nitride and aluminum oxynitride, metal carbides such as silicon carbide, natural graphite, artificial graphite (carbon black) Carbon fiber having a highly crystalline graphite structure, graphite, expanded graphite, diamond, carbon nanotube, carbon nanofiber and other carbon-based materials, wollastonite, zeolite, sericite, kaolin, Mica, clay, pyrophyllite, bentonite, asbestos, talc, alumina silica Silicates such as carbonates, carbonates such as calcium carbonate, magnesium carbonate, and dolomite, and fillers with forms such as particles, irregular shapes, fibers, whiskers, etc., such as sulfates such as calcium sulfate and barium sulfate. Can be mentioned.

  Among these, as the heat conductive filler mainly used for the heat conductive resin layer of the present invention, carbon fibers having a highly crystalline graphite structure are preferable. The growth degree of the graphite crystal structure can be expressed by several physical property values that can be analyzed by an instrument. Examples include physical property values such as crystallite size and interplanar spacing of the graphite crystal, and true density of the carbon material. As the carbon fiber used in the present invention, a carbon fiber having excellent graphitization property of 20 nm or more as a crystallite size (Lc) derived from at least the thickness direction of the hexagonal network surface of the graphite crystal is used as a representative of those physical property values. Is preferred.

If the value of Lc is less than 20 nm, for example, it is difficult to obtain high thermal conductivity exceeding several hundred W / m · K, which tends to be insufficient for the purpose of the present invention.
An example of the carbon fiber excellent in graphitization satisfying these conditions is an anisotropic pitch-based graphitized carbon fiber. The anisotropic pitch-based graphitized carbon fiber will be described in detail later.

The thermally conductive filler is preferably compounded in the range of 20 to 70% by weight, more preferably 25 to 60% by weight, and still more preferably 30 to 50% by weight in the thermally conductive resin layer.
If it is less than 20 parts by weight, the thermal conductivity of the heat conductive resin layer tends to be insufficient, and if it exceeds 70 parts by weight, the mechanical strength and moldability of the heat conductive resin layer are often significantly reduced.

Note that a reinforcing filler for increasing mechanical strength and an additive for improving durability, moldability and the like may be added to the thermally conductive resin layer.
Examples of the reinforcing filler include short glass fibers, short carbon fibers, and short aramid fibers having a fiber length of about 0.1 to 10 mm, more preferably about 0.3 to 6 mm. The carbon short fibers are particularly preferably PAN-based carbon fibers using polyacrylonitrile as a starting material.
Examples of the additive include known dispersibility improvers, mold release agents, flame retardants, emulsifiers, softeners, plasticizers, surfactants, antioxidants, ultraviolet absorbers, infrared absorbers, and the like.

  Regarding mixing of thermally conductive fillers, reinforcing fillers, additives, etc. into the matrix resin, known melt-kneading apparatuses having a single-screw or bi-screw kneading screw, various mixers, blenders, agitators, etc. Can be implemented in combination.

[Detailed disclosure of anisotropic pitch-based graphitized carbon short fiber]
Anisotropic pitch-based graphitized carbon fiber suitably used for the heat conductive filler constituting the heat conductive resin layer is spun using a liquid crystalline pitch, so that developed graphite crystals having an Lc of 20 nm or more are obtained. It has characteristics that are easy to obtain.
The average fiber diameter is preferably in the range of 3 to 20 μm, more preferably 5 to 17 μm, and still more preferably 7 to 15 μm, as the average fiber diameter in terms of perfect circle.

The dispersion value (CV value) indicating the variation of the fiber diameter is a percentage of the value obtained by dividing the standard deviation of the fiber diameter at the time of measuring the predetermined number by the average value of the fiber diameter, but the CV value is in the range of 3-20. It is preferable that it is in the range of 3-15.
In the present invention, it is preferable to use anisotropic pitch-based graphitized carbon fibers in the form of short fibers, and the fiber length is in the range of 30 to 1000 μm, more preferably 50 to 500 μm, and still more preferably 100 to 300 μm as the average fiber length. It is preferable that it exists in.

A preferred method for producing these anisotropic pitch-based graphitized carbon short fibers is, for example, as follows.
Examples of the raw material for the anisotropic pitch-based graphitized carbon fiber include condensed polycyclic hydrocarbon compounds such as naphthalene and phenanthrene, condensed heterocyclic compounds such as petroleum pitch and coal pitch, and the like. Among these, condensed polycyclic hydrocarbon compounds such as naphthalene and phenanthrene are preferable, and mesophase pitch is particularly preferable.

  The mesophase rate of the mesophase pitch is at least 90% or more, more preferably 95% or more, and further preferably 99% or more. Note that the mesophase rate of the mesophase pitch can be confirmed by observing the pitch in the molten state with a polarizing microscope. In addition, you may use a pitch suitably combining 2 or more types as needed.

The pitch softening point temperature is preferably in the range of 230 to 360 ° C. The softening point temperature can be determined by, for example, the Mettler method. When the softening point temperature is lower than 230 ° C., the infusibilization process temperature described later is lowered, and therefore, the infusibilization process takes a long time, which is not preferable. On the other hand, if it exceeds 360 ° C., the pitch is liable to be deteriorated due to thermal decomposition, and the generated gas causes problems such as generation of bubbles in the fiber, which is not preferable.
A more preferable range of the softening point temperature is 250 ° C. or higher and 340 ° C. or lower, and more preferably 260 ° C. or higher and 320 ° C. or lower.

Using this mesophase pitch, a spinning process is first performed to obtain a precursor fiber of anisotropic pitch-based graphitized carbon fiber (hereinafter referred to as precursor fiber).
The spinning method is not particularly limited, but a so-called melt spinning method is preferably used. More specifically, for example, a normal spinning drawing method in which a mesophase pitch discharged from a die is drawn with a winder, a melt blow method using hot air as an atomizing source, a centrifugal spinning method in which a mesophase pitch is drawn using centrifugal force, and the like. It is done.
Among these, it is desirable to use the melt blow method for reasons such as control of the shape of the precursor fibers and high productivity.

Hereinafter, the spinning method of the precursor fiber by the melt blow method will be described in detail.
The shape of the spinning nozzle is not particularly limited, and a perfect circular shape is usually used. However, there is no problem even if an irregularly shaped nozzle such as an ellipse is used in a timely manner.
In general, the ratio L / D of the nozzle hole length L to the hole diameter D is preferably about 2 to 30. If L / D is less than 2, it becomes difficult to increase the shearing force at the time of pitch melting, and if L / D exceeds 30, it is necessary to increase the spinning pressure, and it is necessary to increase the size of the device including ensuring the device strength. And it is difficult to increase the surface density of the spinning holes and the productivity is lowered.

Generally, in order to ensure spinning stability in the melt blow method, the melt viscosity of the pitch when passing through the nozzle holes is preferably in the range of about 1 to 100 Pa · s.
If the melt viscosity of the melt pitch is less than 1 Pa · s, it is difficult to maintain the fiber shape. On the other hand, when the melt viscosity exceeds 100 Pa · s, it is necessary to considerably increase the pressure resistance of the spinning nozzle, which is not desirable in terms of cost performance of the apparatus.

In the spinning process, the fiber diameter of the precursor fiber can be adjusted by changing the nozzle hole diameter, changing the discharge amount of the raw material pitch from the nozzle, or changing the draft ratio of the precursor fiber by blowing air. Is possible.
Of these, the draft ratio can be changed by blowing a gas having a linear velocity of 100 to 20000 m per minute heated to 100 to 400 ° C. in the vicinity of the thinning point of the spinning pitch discharged from the nozzle. . There is no particular restriction on the gas to be blown, but air is desirable from the viewpoint of cost performance and safety.

  From the viewpoint of spinning stability during production, and productivity including the infusibilization / carbonization step described below, the fiber diameter of the precursor fiber is preferably in the range of about 5 to 25 μm as a true circle equivalent average fiber diameter, More preferably, it is 7-20 micrometers.

The precursor fiber spun by the melt blow method is collected, for example, in a web-like form on a belt movable wire net or the like. The thickness, basis weight, density, etc. of the web can be arbitrarily adjusted by setting the spinning conditions and the belt conveyance speed. Moreover, it is also possible to laminate | stack a web by methods, such as a cross wrap, as needed. The basis weight of the web is preferably 150 to 1000 g / m ^{2 in} consideration of productivity and process stability.
The web of precursor fibers thus obtained is conveyed by a belt or the like and sent to the infusibilization process.

  The infusibilization treatment can be performed by a known method. For example, it can be carried out in an oxidizing atmosphere using air or a gas obtained by adding ozone, nitrogen dioxide, nitrogen, oxygen, iodine, bromine to air, but in consideration of safety and convenience, it may be carried out in the air. desirable. The infusibilization process can be performed by either batch process or continuous process, but continuous process is desirable in consideration of productivity.

The infusibilization treatment is preferably carried out at a temperature lower than the softening point temperature of the pitch, and is achieved by applying a heat treatment for a certain time at a temperature of about 150 to 350 ° C. A more preferable temperature range is 160 to 340 ° C.
A heating rate of 1 to 10 ° C./min is preferably used. In the case of continuous treatment, the above heating rate can be achieved by sequentially passing through a plurality of reaction chambers set at arbitrary temperatures. A more preferable range of the heating rate is 3 to 9 ° C./min in consideration of productivity and process stability.

The web that has been infusibilized is conveyed by a belt or the like and sent to a carbonization process.
Carbonization can also be performed by a known method. For example, it can be performed by heating and heat-treating the web to a temperature of about 600 to 2500 ° C. in a vacuum or in a non-oxidizing atmosphere using an inert gas such as nitrogen, argon, or krypton.

  Within the carbon fiber that has been carbonized, there is a significant development of the graphite crystal structure. Generally, the higher the heat treatment temperature, the longer the heat treatment time, and the greater the total heat applied to the fiber, the larger the crystal structure develops. . However, when the step of the advanced graphitization treatment described later is performed, since the remarkable growth of the graphite crystal structure can be expected in the same step, the heat treatment temperature, time, total heat amount, etc. of the carbonization treatment step may be appropriately suppressed.

The carbonization process is preferably performed at normal pressure and in a nitrogen atmosphere in consideration of cost. The carbonization treatment can be either batch processing or continuous processing, but continuous processing is desirable in consideration of productivity.
The web that has been carbonized is preferably subjected to a coarse pulverization step. The coarse pulverization step is a step of throwing the web into various cutting machines and / or crushing / pulverizing machines, destroying the shape of the web, and cutting the carbon fibers inside the web into short fibers having an appropriate fiber length. .

The purpose of cutting into an appropriate length of short fiber is to improve productivity, production stability, controllability, etc. in the later-described advanced graphitization process and wet pulverization process. The reason for mentioning productivity here is that the advanced graphitization process and wet pulverization process are often performed in batch processing because of the equipment, so it is necessary to increase the amount of carbon fiber that can be input at once in batch processing. This is because it is generally preferable to use short fibers having an appropriate fiber length rather than webs. That is, the main purpose is to increase the bulk density when carbon fibers are filled in batch processing containers and devices, and the bulk density of the short fiber-like carbon fibers is at least 0.1 g / cm ³ or more, more preferably It is preferable to perform coarse pulverization so as to be 0.3 g / cm ³ or more, more preferably 0.5 g / cm ³ or more, and most preferably 0.7 g / cm ³ or more.

  As the cutting machine, for example, a guillotine type, a single axis, a biaxial and a multi-axis rotary type cutter can be preferably used. Examples of the crushing / pulverizing machine include hammer type, pin type, ball type, bead type and rod type using impact action, high-speed rotation type using collision between particles, roll type using compression / tearing action. Cone-type and screw-type crushing / pulverizing machines are preferably used. If necessary, cutting and crushing / crushing can be configured by a plurality of machines.

  Regarding the control of the bulk density or fiber length of short fibrous carbon fibers, select a suitable device / model or a combination thereof for the desired fiber length range, and the number of rotations and supply of rotors / rotating blades, etc. It can be preferably controlled by appropriately adjusting the amount, clearance between blades, residence time in the system and the like.

  If the fiber length control is insufficient with only a cutting machine or a crushing / pulverizing machine, a classification step can be further added. In other words, the classification step is a step of performing a sieving operation, and is a step of efficiently separating a component having a fiber length not less than a predetermined value or less than a predetermined value by sieving, a vibration sieving method, a centrifugal separation method, an inertial force method, a filtration. It implements using various classifiers, such as a formula.

  The short fiber-like carbon fiber that has undergone the coarse pulverization step is preferably subjected to a process of advanced graphitization treatment in which heat treatment at a higher temperature is performed for the purpose of further growing the graphite crystal structure inside the carbon fiber, if necessary. . Specifically, the advanced graphitization process is performed using, for example, an Atchison furnace, an electric furnace, etc., in a vacuum or in a non-oxidizing atmosphere using an inert gas such as nitrogen, argon, krypton, etc. This is a step of performing heat treatment at around 3500 ° C.

[Disclosure of polycarbonate resin]
As described above, the light-transmitting resin layer and / or the heat-conductive resin layer of the present invention is made of a polycarbonate resin, particularly a copolymer polycarbonate containing a copolymer component such as an aromatic polycarbonate or an aliphatic ring. It is preferable to use it.

  As the polycarbonate resin, an aromatic polycarbonate resin obtained by reacting a dihydric phenol and a carbonate precursor is preferable. Typical examples of the dihydric phenol used here include 2,2-bis (4-hydroxyphenyl) propane (commonly called bisphenol A), bis (4-hydroxyphenyl) methane, 1,1-bis (4 -Hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3, 5-dibromophenyl) propane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, bis (4-hydroxyphenyl) ether, 4,4′-dihydroxydiphenyl, bis (4-hydroxyphenyl) sulfide and Bis (4-hydroxyphenyl) sulfone and the like can be mentioned. A preferred dihydric phenol is bis (4-hydroxyphenyl) alkane, and bisphenol A is particularly preferred.

  As the carbonate precursor, carbonyl halide, carbonate ester, haloformate or the like is used, and specific examples include phosgene, diphenyl carbonate, dihaloformate of dihydric phenol, and the like.

  In producing an aromatic polycarbonate resin by reacting the above dihydric phenol with a carbonate precursor, the dihydric phenol can be used alone or in combination of two or more kinds, and the aromatic polycarbonate resin is trifunctional or more multifunctional. It may be a branched polycarbonate resin copolymerized with an aromatic compound or a mixture of two or more aromatic polycarbonate resins. Moreover, you may use a catalyst, a molecular weight regulator, antioxidant, etc. as needed.

  The molecular weight of the aromatic polycarbonate resin is preferably around 12000 to 26000. Expressed as specific viscosity (ηsp), for example, when an aromatic polycarbonate resin is obtained using bisphenol A as a dihydric phenol and phosgene as a carbonate precursor, the concentration is measured at a temperature of 20 ° C. with a 0.7 g / dl methylene chloride solution. A specific viscosity (ηsp) of 0.15 to 1.5, more preferably 0.2 to 0.8 is preferred.

[Application to lighting equipment]
The composite hollow pipe of the present invention is preferably applied to a pipe-shaped lighting device having a light source such as an LED inside. An example of such use is illustrated in FIGS. 15 to 17, but the structure in which the whole or a part of the mounting board of the LED element is in direct contact with the heat conductive resin layer or through an adhesive, an adhesive, or the like. By taking the heat, the heat generated by the LED element can be efficiently transferred to the heat conductive resin layer via the mounting substrate.

These structural designs are preferably performed in consideration of the shape of the LED element mounting substrate and the arrangement of the LED elements and other mounting components. Depending on the structural design, the shapes of the light-transmitting resin layer and the heat conducting resin layer are preferred. (Cross sectional shape) can be changed as appropriate.
These mounting substrates are preferably disposed on the thermally conductive resin layer, and it is desirable that there is no interstices such as air at the interface between them.

As a method for disposing the mounting substrate on the thermally conductive resin layer, for example, there is a method of introducing the mounting substrate while sliding it from the end of the hollow pipe. In this case, the mounting substrate as illustrated in FIG. It is preferable that a guide shape (for example, a claw-like structure) for fixing the position is previously formed by batch molding. This claw-like structure is preferably formed together with the pipe portion using a light transmissive resin constituting the pipe portion. The length of the nail-like structure is preferably about 1 to 4 mm.
By positioning the mounting substrate between the guide shape (claw-like structure) and the heat conductive resin layer, the mounting substrate can be easily positioned, and the mounting substrate, the heat conductive resin layer, The surface contact can be secured stably.

  Also, by applying appropriate grease or liquid adhesive in advance between the mounting board and the thermally conductive resin layer, it is possible to prevent air from being caught in the interface when the mounting board is slid. . Furthermore, by filling these liquids into the heat conductive resin layer and the minute surface irregularities of the mounting substrate, it becomes possible to further reduce the presence of the air layer at the interface. The grease and the liquid adhesive are preferably selected with a thermal conductivity of 1 W / mK or more. In addition, if a groove having a width and depth of about 0.5 mm is formed in advance on the surface of the mounting substrate or the heat conductive resin layer and the liquid is filled in the groove, the surface tension Accordingly, the grease and the liquid adhesive can be easily spread with a thin and uniform thickness from the inside of the groove to the entire interface, and a more uniform interface contact state can be stably obtained, which may be preferable.

  In addition to the above, the method of fixing the mounting substrate on the thermally conductive resin layer is preferably exemplified by a method of fixing via a pressure-sensitive adhesive sheet. In the case of fixing using an adhesive sheet, before introducing the mounting substrate into the pipe, the adhesive sheet is pasted on at least a part of the mounting substrate in advance, and after the mounting substrate is introduced onto the thermally conductive resin layer, the predetermined It is sufficient to crimp at the position. In the case where the mounting substrate has some warpage, it is also preferable to use an appropriate jig for the purpose of correcting the warping of the mounting substrate and making the surface pressure constant during pressure bonding.

  Examples of the pressure-sensitive adhesive sheet include those obtained by forming an acrylic or silicone-based pressure-sensitive resin into a sheet, and it is more preferable to use a heat-conductive pressure-sensitive adhesive sheet obtained by mixing a heat-conductive filler in the resin. .

By the way, although the edge part of the composite hollow pipe of this invention becomes an opening part, when utilizing as an illuminating device, it becomes necessary to seal this opening part.
Examples of this purpose include a method of bonding and fixing an appropriate resin plate to the end of the hollow pipe, and a method of using a resin molded cap that can be inserted and fixed in the hollow pipe. As for this sealing part, it is usual that a power supply wiring passes through the inside, or it has a role as a joint part, and it is preferable to use the material excellent in mechanical strength and electrical reliability. When using a resin-molded cap, it is also preferable to use a resin-molded cap or the like formed by combining a packing structure such as an O-ring inside as shown in FIG.

  The composite hollow pipe of the present invention has a power source circuit (AC / DC conversion circuit, AD conversion circuit, transformer circuit, constant current circuit, constant current circuit, etc.) for driving the light source device such as an LED. A substrate on which an overcurrent protection circuit, an intermittent lighting circuit, a dimming control circuit, and the like are mounted may be provided. A sensor that measures the temperature of the LED and a control circuit that automatically controls the input power to the LED may be provided so that the LED temperature falls within a predetermined range.

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

(1) Average fiber diameter of carbon fiber:
According to JIS R7607, the fiber diameter of 60 carbon fibers was measured as an average fiber diameter in terms of perfect circle using a scale under an optical microscope, and the average value was obtained from the average value.

(2) Coefficient of variation of carbon fiber diameter (CV value):
It calculated | required as a percentage of the value which remove | divided the standard deviation of the fiber diameter measured value of the said 60 carbon fibers by the average value.

(3) Average fiber length of short carbon fiber:
Under the optical microscope, 2000 carbon short fibers were measured using a length measuring instrument (10 fields of view, measured 200 at a time), and the number average fiber length was obtained. The magnification was appropriately adjusted according to the fiber length to be measured.

(4) Observation of cross-sectional structure of carbon fiber Observation was performed using a scanning electron microscope (S-2400, manufactured by Hitachi High-Technology Corporation).

(5) True density of carbon fiber:
Measurements were made using the floatation method. That is, a mixed solution of dibromoethane having a specific gravity of 2.17 (g / cm ³ ) and bromoform having a specific gravity of 2.89 (g / cm ³ ) is prepared in a cylinder and controlled at a temperature of 25 ± 0.2 ° C. Carbon short fibers are infiltrated into the above mixed solution, held at 1.3 kPa for 3 minutes, and then stirred until the carbon short fibers come to the center of the mixed solution. After 10 minutes, dibromoethane is added if the short carbon fibers emerge, and bromoform is added dropwise if the short fibers appear to sink. This operation was repeated until the short carbon fibers were stationary, and after the stationary, the density of the mixed liquid was measured with specific gravity floating to obtain the true density of the carbon fibers.

(6) Crystallite size and plane spacing of graphite crystals:
Obtained by the X-ray diffraction method, the crystallite size (Lc) derived from the thickness direction of the hexagonal network surface of the graphite crystal and the interplanar spacing (d002) of the graphite crystal are obtained using diffraction lines from the (002) plane. The crystallite size (La) derived from the growth direction of the network surface was determined using diffraction lines from the (110) plane.
In addition, the data analysis and the numerical calculation method from the X-ray diffraction measurement result were performed according to the Gakushin method.

(7) Thermal conductivity and electrical resistivity of carbon fiber:
The carbon fiber was not coarsely pulverized, and the single-fiber carbon fiber was extracted as a sample from the web after the carbonization process or the highly graphitization process, and the measurement was performed as follows.
That is, after the fiber extracted as a sample is fixed on a flat surface, a pair of measurement terminals are provided at a predetermined interval on the fiber, and the electrical resistivity between both terminals is measured. The fiber portion to be the terminal portion was coated with a silver paste to reduce the contact resistance, and the electrical resistivity was measured by a four-terminal method.
After measuring the electrical resistivity of the carbon fiber in the fiber axis direction in this way, the thermal conductivity is calculated from the following equation representing the relationship between the thermal conductivity and the electrical resistivity disclosed in JP-A-11-117143. Asked.
K = 1272.4 / ER-49.4
Here, K represents the thermal conductivity (unit: W / (m · K)) of the carbon fiber, and ER represents the electrical specific resistance (unit: μΩ · m) of the carbon fiber.

(8) Thermal conductivity of resin layer:
Separately, it is injection-molded into a 50 mm x 90 mm x 2 mm thick plate, and a sample piece for measurement is cut out from this molded plate, and heat conduction in the in-plane direction of the sample is performed using a laser flash method (LFA-457 manufactured by NETZSCH). The rate was measured.
For measurement in the in-plane direction, the molded plate is first cut out in a thickness of 2 mm × 10 mm × 2 mm, and five sample pieces are stacked to obtain a sample piece of 10 mm × 10 mm × 2 mm thickness which is a necessary size for the measurement. Was made and measured.

(9) Flexural modulus of resin layer:
Measurements were performed according to ISO 178.

(10) Light transmittance of light transmissive resin layer:
Using a test piece having a side of 150 mm and a thickness of 3 mm, the total light transmittance in the thickness direction was measured according to ASTM D1003 using a haze meter HR-100 manufactured by Murakami Color Research Laboratory Co., Ltd.

(11) Dispersion degree of light transmissive resin layer:
A test piece having a side of 150 mm and a thickness of 3 mm was used, and the measurement was performed using a dispersion meter manufactured by Nippon Denshoku Industries Co., Ltd. The measuring method is shown in FIG. Note that the degree of dispersion means the angle of γ when the amount of transmitted light is 50 when the amount of transmitted light is 100 when γ = 0 ° when a light beam is vertically applied to the surface of the test piece in FIG. .

(Creation of anisotropic pitch-based graphitized carbon short fibers)
A pitch made of a condensed polycyclic hydrocarbon compound was used as a main raw material. The optical anisotropy ratio was 100%, and the softening point was 288 ° C. A pitch melted at 335 ° C., using a base with a hole diameter of 0.2 mmφ, heated air is ejected from the slit at a linear velocity of 10,000 m / min, the molten pitch is pulled, and the average fiber diameter is obtained by the melt blow method. Produced a carbon fiber precursor of about 11.0 μm.
The spinning nozzle L / D in this spinning was 10. The melt viscosity of the pitch at the time of spinning at a temperature of 335 ° C. and a shear rate of 6000 s ⁻¹ was 10.5 Pa · s.
The obtained carbon fiber precursor was collected on a perforated belt and further adjusted with a cross wrapper so that the basis weight was 350 g / m ² to obtain a carbon fiber precursor web.
Next, the carbon fiber precursor web was heated from 170 ° C. to 290 ° C. at an average heating rate of 4 ° C./min for infusibilization, and then carbonized at 800 ° C. in a nitrogen atmosphere. A carbonized fiber web was obtained.
Thereafter, the carbonized fiber web was coarsely pulverized to obtain a coarsely pulverized carbonized fiber having an average fiber length of about 200 μm.
The carbonized fiber coarsely pulverized product was subjected to a heat treatment at 3100 ° C. in an electric furnace in a non-oxidizing atmosphere as an advanced graphitization treatment to prepare a target graphitized carbon short fiber.
The average fiber length of the graphitized carbon short fiber thus obtained is 8.0 μm, the true specific gravity of the carbon fiber is 2.20 g / cm ³ , and the crystal originates in the thickness direction of the hexagonal mesh surface of graphite. The crystallite size (La) is 44 nm, and the crystallite size (La) derived from the hexagonal network growth direction is 106 nm. The interplanar spacing (d002) of the graphite crystal was 0.3365 nm.
Furthermore, the electrical resistivity of the carbon fiber was 1.6 μΩ · m, and the thermal conductivity was 750 W / (m · K).

(Creation of heat conductive resin)
40 parts by weight of the anisotropic pitch-based graphitized carbon short fiber filler thus prepared and 60 parts by weight of an aromatic polycarbonate resin (Panlite L-1225, ηsp = 0.41 manufactured by Teijin Chemicals Ltd.) are melt-kneaded. Thus, a heat conductive resin A was obtained.
Furthermore, 45 parts by weight of an anisotropic pitch-based graphitized carbon short fiber filler and 55 parts by weight of an aromatic polycarbonate resin (Teijin Kasei Panlite L-1225, ηsp = 0.41) are melt-kneaded. Thermally conductive resin B was obtained.
The thermal conductivities of the thermal conductive resins A and B were 6.2 W / m · K and 8.3 W / m · K, respectively, and the flexural moduli were 11.5 MPa and 13.1 MPa, respectively.

(Creation of light transmissive resin)
95 parts by weight of aromatic polycarbonate resin (Panlite L-1225 manufactured by Teijin Chemicals Ltd., ηsp = 0.41), 1 part by weight of calcium carbonate (Sipron A manufactured by Sipro Kasei Co., Ltd., weight average particle diameter 10 μm), short glass fiber 4 Part by weight (PFE-301 manufactured by Nitto Boseki Co., Ltd., average diameter 9 μm, average length 40 μm) was melt-kneaded to obtain a light-transmitting resin A having light diffusibility.
In addition, 90 parts by weight of aromatic polycarbonate resin (Panlite L-1225 manufactured by Teijin Chemicals Ltd., ηsp = 0.41), 5 parts by weight of calcium carbonate (Sipron A manufactured by Cypro Kasei Co., Ltd., weight average particle diameter 10 μm), short glass fiber 5 parts by weight (PFE-301 manufactured by Nitto Boseki Co., Ltd., average diameter 9 μm, average length 40 μm) was melt-kneaded to obtain a light transmissive resin B having light diffusibility.
In addition, 80 parts by weight of aromatic polycarbonate resin (Panlite L-1225 manufactured by Teijin Chemicals Ltd., ηsp = 0.41), 10 parts by weight of calcium carbonate (Sipron A manufactured by Cypro Kasei Co., Ltd., weight average particle diameter 10 μm), short glass fiber 10 parts by weight (PFE-301 manufactured by Nittobo Co., Ltd., average diameter 9 μm, average length 40 μm) was melt-kneaded to obtain a light-transmitting resin C having light diffusibility.
The total light transmittances of the light transmissive resins A, B, and C were 78.5%, 48.5%, and 38.8%, respectively, and the degrees of dispersion were 25 degrees, 58 degrees, and 64 degrees, respectively.

(LED mounting board specifications)
As the LED mounting substrate, a white LED element (output 1 W) manufactured by Mitsubishi OSRAM Co., Ltd. mounted in one direction at intervals of 20 mm on one side of a three-layer CCL flexible substrate was used.
That is, an LED is mounted on one side of a three-layer CCL flexible substrate formed by laminating a polyimide film with a thickness of 50 μm, an epoxy adhesive layer with a thickness of 20 μm, and rolled copper with a thickness of 32 μm, and heat on the opposite side of the LED mounting surface with a thickness of 50 μm. An aluminum composite substrate (hereinafter referred to as an LED mounting substrate) having a configuration in which an aluminum plate having a thickness of 1 mm was attached via a conductive double-sided acrylic adhesive sheet was used.
In Examples and Comparative Examples, the temperature measurement directly under the LED elements was performed in order to compare the heat dissipation status of the LED elements. That is, the measurement was performed by inserting a thin film thermocouple having a thickness of 100 μm (manufactured by Anritsu Keiki Co., Ltd.) at several locations at the interface between the three-layer flexible substrate and the thermally conductive double-sided acrylic pressure-sensitive adhesive sheet and immediately below the LED element mounting portion.

[Example 1]
A composite hollow pipe made of the heat conductive resin A and the light transmissive resin A was prepared. That is, the cross-sectional structure is the shape shown in FIG. 5, the outer diameter of the pipe is 20 mm, the length is 680 mm, the area ratio of the light-transmitting resin layer to the total surface area of the outer periphery of the pipe is 65%, and the area ratio of the heat conductive resin layer Was 35%, the average thickness of the light-transmitting resin layer was 1.5 mm, and the average thickness of the thermally conductive resin layer was 3.5 mm.
For producing this pipe, a two-color extrusion molding apparatus schematically shown in FIG. 22 was used. That is, the heat conductive resin A and the light transmissive resin A were melt-extruded from separate extruding devices, joined in a heat die, and extrusion molding was completed to a desired shape while proceeding with melt adhesion.
At this time, a stationary single-axis full-flight extruder was used as the extruder 67 in FIG. 22, but a single-axis full-flight extruder with a movable lifting function was used as the extruder 68 in FIG. The reason for this is that in the case of a single-axis full-flight extruder with a movable lifting function, positioning when assembling the mold and each extruder is easy.
The direction of the resin flowing into the mold is from the rear. The other is from above. However, the direction of the resin flowing from the extruder with the moving / lifting function is not limited to only from above, but may be flown from the rear or side.

Two parameters that are important as extruder setting conditions are the molten resin discharge amount and the molten resin temperature. First, the resin weight per unit time discharged from each extruder needs to be uniform. This can be obtained by making the extruder screw rotation speed constant and the shape of the extruder screw, but this time, the stability of the discharge amount was obtained by using a screw exclusively for the polycarbonate resin.
Moreover, keeping the molten resin temperature constant was obtained by the PID control function of the heater temperature controller. In particular, the heat-conductive resin A and the light-transmitting resin A used this time have a significant difference in melt viscosity at the same temperature. The heat conductive resin A has a high melt viscosity, whereas the light-transmitting resin A has a low melt viscosity. A characteristic of polycarbonate resin, which is an amorphous resin, is that melt viscosity depends on the melting temperature and decreases as the temperature rises. This time, this property is used to conduct heat to the melting temperature of the light-transmitting resin A. The melt viscosity was made as close as possible by increasing the melting temperature of the conductive resin A. At this time, the difference in melt viscosity is preferably 4 or less in terms of MI value, but was 2 or less in actual molding.
Thus, the resin merged and fused in the heat die was melted and drawn into the sizing die. By setting the sizing die below the resin glass transition temperature and shaping it to the shape of the inner surface of the sizing die, a hollow pipe shape is obtained. Furthermore, in the water tank, the heat remaining in the drawn hollow pipe was removed by spraying cooling water. At this time, there is a method of spraying the cooling water, but there is also a method of storing water in the water tank and passing it through.

Next, the hollow pipe that came out of the water tank was taken up by a belt type servo motor direct drive type take-up machine. At this time, it is important to keep the take-up speed constant. The thickness of the hollow pipe can be controlled by the balance between the amount of resin extruded from the two extruders and the speed of the take-up machine.
In addition, the speed of the take-up machine may be automatically controlled using equipment called an edge controller for the purpose of correcting slight variations in the amount of extrusion.
The edge controller is a sensor that is installed in the space between the heat die and the sizing die and senses the amount of molten resin dripping, and feeds back this amount of variation to the take-up machine to automatically control the speed. Although it is possible to feed back to each of the take-up machine and the extruder, it is preferable to control the take-up side for the purpose of reacting linearly. This time, it was not used because the variation of the resin discharge amount was not large compared with the required accuracy of the product.

Finally, composite hollow pipe products were obtained by automatic cutting to the specified dimensions by an automatic cutting machine.
The pipe was provided with a claw portion shape having a thickness of 1.5 mm and a length of 3 mm made of light-transmitting resin A for the purpose of mechanically fixing the LED mounting substrate. (That is, the cross-sectional structure is the shape shown in FIG. 13)
A commercially available LED mounting board coated with heat conductive grease on the aluminum surface side is slid into the composite hollow pipe from the end, laminated and fixed on the heat conductive resin layer, and polycarbonate resin at both ends of the pipe An LED lighting device was made by fitting a cap made and sealing. A schematic cross-sectional view of this LED illumination device is shown in FIG.
In this LED lighting device, after a current of 150 mA was passed through each LED element, the temperature immediately under the LED element after 30 minutes was 63 ° C. on average. Further, in this LED lighting device, almost no warp in the pipe length direction was observed, and the lighting device was very light.

[Example 2]
A composite hollow pipe and an LED lighting device were prepared in the same manner as in Example 1 except that the heat conductive resin B was used instead of the heat conductive resin A in Example 1.
In this LED lighting device, after a current of 150 mA was passed through each LED element, the temperature immediately under the LED element after 30 minutes was 61 ° C. on average. Further, even in this LED lighting device, the warp in the pipe length direction was hardly observed, and the lighting device was very light.

[Example 3]
A composite hollow pipe made of the heat conductive resin A and the light transmissive resin C was prepared. That is, the cross-sectional structure is the shape shown in FIG. 8, the outer diameter of the pipe is 32 mm, the length is 680 mm, and the area ratio of the portion where the light-transmitting resin layer exists alone in the entire surface area of the outer periphery of the pipe is 60%, The remaining 40% area is formed by laminating a light-transmitting resin layer as an outer layer and a heat conductive resin layer as an inner layer. The average thickness of the portion where the light-transmitting resin layer is present alone is 1.5 mm, the average thickness of the light-transmitting resin layer in the portion laminated with the thermally conductive resin layer is 1 mm, and the thinnest portion The wall thickness was 0.8 mm. The average thickness of the heat conductive resin layer was 5 mm.
The same two-color extrusion molding apparatus as in Example 1 was also used for producing this pipe. That is, the heat-conductive resin A and the light-transmitting resin C were melt-extruded from separate extruders, joined in a die of a main extruder, and extrusion molding was completed into a desired shape while progressing melt adhesion.
Also, this pipe was provided with a claw portion shape having a thickness of 1.5 mm and a length of 3 mm made of light-transmitting resin C for the purpose of mechanically fixing the LED mounting substrate.

As in Example 1, the LED mounting substrate coated with commercially available heat conductive grease on the aluminum surface side was slid into the inside from the end of the composite hollow pipe, and laminated and fixed on the heat conductive resin layer. A polycarbonate resin cap was fitted on both ends of the pipe and sealed to prepare an LED lighting device. A schematic cross-sectional view of this LED illumination device is shown in FIG.
After a current of 150 mA was passed through each LED element, the temperature immediately below the LED element after 30 minutes was 62 ° C. on average. Further, even in this LED lighting device, the warp in the pipe length direction was hardly observed, and the lighting device was very light.
Furthermore, due to the light scattering property of the light-transmitting resin layer, the light spots of the LED elements arranged at intervals of 20 mm almost disappeared and can be used as highly uniform surface illumination and linear illumination. .

[Example 4]
A composite hollow pipe made of the heat conductive resin A and the light transmissive resin B was prepared. That is, the cross-sectional structure is the shape shown in FIG. 11, the outer diameter of the pipe is 39 mm, the length is 1160 mm, the area ratio of the light-transmitting resin layer in the total surface area of the outer periphery of the pipe is 53%, and the area ratio of the heat conductive resin layer Was 47%.
The average thickness of the light transmissive resin layer was 1.5 mm, the average thickness of the heat conductive resin layer was 4.5 mm, and the thickness of the thinnest part was 2 mm.
The same two-color extrusion molding apparatus as in Example 1 was also used for producing this pipe. That is, the heat-conductive resin A and the light-transmitting resin C were melt-extruded from separate extruders, joined in a die of a main extruder, and extrusion molding was completed into a desired shape while progressing melt adhesion.

In Example 4, the aluminum surface of the LED mounting substrate is such that the 5 mm wide portions are in direct contact with the thermally conductive resin layer, and a 50 μm thick thermally conductive acrylic adhesive sheet is applied to this contact portion. Paste in advance. Then, through this adhesive sheet, the LED mounting substrate is pressure-bonded and fixed to a predetermined position on the heat conductive resin layer, and a polycarbonate resin cap is fitted to both ends of the pipe, and the LED lighting device is bonded and sealed. Created. A schematic cross-sectional view of this LED lighting device is shown in FIG.
After a current of 150 mA was passed through each LED element, the temperature immediately below the LED element after 30 minutes was 63 ° C. on average. Further, even in this LED lighting device, the warp in the pipe length direction was hardly observed, and the lighting device was very light.
Furthermore, due to the light scattering property of the light-transmitting resin layer, the light spots of the LED elements arranged at intervals of 20 mm almost disappeared and can be used as highly uniform surface illumination and linear illumination. .

[Comparative Example 1]
As a comparison with Examples 1 and 2, a light-transmitting resin A is used, and the outer surface represented by the schematic diagram of FIG. Made a hollow pipe.
Using the same LED mounting substrate as in the example, an LED lighting device was created, and a current of 150 mA was passed through each LED element, and then the average temperature directly under the LED element after 30 minutes was 72 ° C., Example 1 Compared with 2, the temperature was significantly higher. Further, in this LED lighting device, significant warpage was recognized in the pipe length direction due to its own weight.

[Comparative Example 2]
As a comparison with Example 3, a light-transmitting resin C is used, and the entire outer surface of the pipe is composed of only a light-transmitting resin layer having a thickness of 1.5 mm. Created a pipe.
Using the same LED mounting substrate as in the example, an LED lighting device was created, and a current of 150 mA was passed through each LED element. Then, the temperature immediately below the LED element after 30 minutes was 70 ° C. on average, Example 3 The temperature was significantly higher than Further, in this LED lighting device, significant warpage was recognized in the pipe length direction due to its own weight.

[Comparative Example 3]
As a comparison with Example 4, a light-transmitting resin B was used, and a hollow pipe having an outer shape of 39 mm represented in the schematic diagram of FIG.
Using the same LED mounting substrate as in the example, an LED lighting device was created, and a current of 150 mA was applied to each LED element, and then the average temperature immediately below the LED element after 30 minutes was 69 ° C., Example 4 The temperature was significantly higher than Further, in this LED lighting device, significant warpage was recognized in the pipe length direction due to its own weight.

1, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 32, 37, 42, 47, 53 Light transmissive resin layers 2, 5, 31, 36, 41, 46, 55 LED element 3, 6, 33, 38, 43, 48, 54 LED mounting substrate 7 Metal heat sink 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 35, 40, 45 , 50, 58 Thermally conductive resin layers 28, 30 Mounting substrate fixing guide structure (claw-like structure)
29 Guide structure (claw-like structure) length 34, 39, 44, 49, 56 Low thermal resistance interface material 51 Wiring 52 Connector 57, 60 Resin molding cap 59 Packing structure (O-ring, etc.)
61 Light source for measuring dispersity 62 Incident light (normal incident light)
63 Sheet 64 with a light-transmitting resin layer Output light (scattered light)
65 Dehumidified air circulating hopper dryer 66 for the first molding material (for example, thermally conductive resin) 66 Dehumidified air circulating hopper dryer 67 for the second molding material (for example, light transmissive resin) 67 Single-axis full-flight extruder 68 Single-axis full flight extruder (with moving / lifting function)
69 Heat dice 70 Sizing dice 71 Water tank 72 Belt servo motor direct drive take-off machine 73 Two-color hollow pipe product (before cutting)
74 Cutting machine 75 Two-color hollow pipe product (after cutting)

Claims (15)

  A one-dimensional hollow pipe having a similar cross-sectional shape, a light-transmitting resin layer made of a resin or resin composition having a light transmittance of 35% or more, and a resin having a thermal conductivity of 2 W / m · K or more A composite hollow pipe configured by combining a thermally conductive resin layer made of a composition.   In the outer peripheral surface of the composite hollow pipe, 40 to 80% of the surface area is composed of a light-transmitting resin layer and 20 to 60% of the surface area is composed of at least a heat conductive resin layer with respect to the total surface area of the outer peripheral surface. The composite hollow pipe according to claim 1, wherein:   2. The composite hollow pipe according to claim 1, wherein an outer peripheral surface of the composite hollow pipe is formed of a light-transmitting resin layer, and an area of 20 to 60% of the outer peripheral surface is configured to have a heat conductive resin layer on the inner periphery.   The composite hollow pipe according to any one of claims 1 to 3, wherein a resin layer different from the heat conductive resin layer having an average thickness of 0.03 to 3 mm is laminated on the outer peripheral side of the heat conductive resin layer.   The composite hollow pipe according to any one of claims 1 to 4, wherein the light transmissive resin layer and the heat conductive resin layer are integrally formed by fusion bonding.   The light transmissive resin layer is made of a resin composition containing at least a light diffusing filler in the range of 0.5 to 40% by weight, and the total light transmittance of the sheet when formed into a sheet having a thickness of 3 mm is 35% or more. The composite hollow pipe according to any one of claims 1 to 5, wherein the degree of dispersion is 20 degrees or more.   The thermally conductive resin layer includes at least a resin serving as a matrix and a thermally conductive filler, and the thermally conductive filler is composed of a resin composition in a range of 20 to 70% by weight. The composite hollow pipe according to any one of 1 to 6.   The thermally conductive filler is an anisotropic pitch-based graphitized carbon short fiber having a crystallite size (Lc) derived from at least a thickness direction of a hexagonal network surface of a graphite crystal of at least 20 nm or more. 8. The composite hollow pipe according to 7.   The composite hollow pipe according to any one of claims 1 to 8, wherein the resin constituting the light transmissive resin layer is made of a thermoplastic resin.   The composite hollow pipe according to any one of claims 1 to 9, wherein a resin constituting the thermally conductive resin layer is made of a thermoplastic resin.   The composite molded pipe according to any one of claims 1 to 10, wherein the matrix resin of the light transmissive resin layer is a thermoplastic resin made of a polycarbonate or a polymer thereof.   The composite molded pipe according to any one of claims 1 to 11, wherein the matrix resin of the thermally conductive resin layer is a thermoplastic resin made of a polycarbonate or a polymer thereof.   The composite hollow pipe according to any one of claims 1 to 12, wherein the matrix resin of the light-transmitting resin layer and the matrix resin of the heat conductive resin layer are made of the same kind or resins compatible with each other. .   A linear or planar light source is characterized by laminating and mounting a mounting substrate of LED elements on at least a part of the thermally conductive resin layer of the composite molded pipe according to any one of claims 1 to 13. LED lighting device.   At least, a thermoplastic resin or thermoplastic resin composition having optical transparency and a thermoplastic resin composition having thermal conductivity are melt-extruded from a plurality of different extruders and then connected to the plurality of extruders. The composite hollow pipe according to any one of claims 1 to 13, wherein the composite hollow pipe is manufactured by a two-color extrusion molding method including a step of integrating in a single die and then cooling and solidifying. Method.