KR20220127992A - Heat dissipation composite material and reflector for projection lamp manufactured using same - Google Patents

Abstract

The present invention relates to a heat-dissipating composite material and a reflector for a projection lamp manufactured therefrom, and more particularly, to a heat-dissipating composite material with lightweight and high strength by mixing alumina and carbon fiber with polyamide resin and a reflector for a projection lamp manufactured therefrom.

Description

HEAT DISSIPATION COMPOSITE MATERIAL AND REFLECTOR FOR PROJECTION LAMP MANUFACTURED USING SAME

The present invention relates to a heat dissipation composite material and a reflector for a projection lamp manufactured therefrom, and more particularly, to a heat dissipation composite material having light weight and high strength by mixing alumina and carbon fiber with a polyamide resin, and a projection manufactured therefrom It relates to a reflector for a lamp.

In general, lighting equipment refers to a device that adjusts brightness and fixes or protects the light source by reflecting, refracting, or transmitting the light of the light source. It may be divided into direct lighting equipment and direct lighting equipment, and may be classified into incandescent lamps, fluorescent lamps, stands, floodlights, street lamps, and stage lighting according to the purpose of use.

Among the lighting devices discussed above, incandescent lamps or fluorescent lamps are commonly used. Conventional incandescent lamps or fluorescent lamps are out of focus due to leakage of visible light when emitting light. , and there was a problem that the lifespan was short.

Accordingly, in recent years, LED lighting devices implemented with LEDs (Light Emitting Diodes), which are advantageous in various aspects compared to incandescent lamps or fluorescent lamps, have been developed and sold. LED refers to a light emitting diode, which is a semiconductor device that emits light, and emits light of various colors such as red, green, blue, and yellow. In general, a light emitting diode, that is, an LED has a pn junction structure, and when a forward current is applied to the diode, electrons in the n region of the chip are accelerated by an electric field and move to the p region, and the acceptor level (Acceptor Level) in the p region ) or recombine with holes in the valence band state to emit light with energy corresponding to the potential difference depending on the material of the chip. This phenomenon is called injection-type electroluminescence, and this device is called LED.

A lamp implemented with an LED requires only about 19% of power consumption compared to a conventional lamp implemented with an incandescent lamp, and only requires about 50% of power consumption compared with a conventional lamp implemented with a fluorescent lamp. LED lamps can minimize eye fatigue even when used for a long period of time and have an advantage of about 10 times longer than incandescent lamps and 8 times longer than fluorescent lamps.

Although the LED lighting device implemented with such LEDs has very good performance, on the other hand, if the heat generated from the LED is not properly discharged, the LED or its driving circuit may deteriorate and the lifespan may be shortened.

In order to solve this problem, a heat sink having excellent thermal conductivity is attached to the LED lighting device, so that the heat generated from the LED lighting device is generally designed to be discharged into the air.

Here, the currently widely used material for the heat sink is a metal material such as aluminum. The heat sink of this metal material has excellent thermal conductivity and excellent heat dissipation properties, but does not conform to the trend of reducing the weight of the lighting equipment by increasing the weight of the lighting equipment. There is a problem of high processing cost, such as anodizing.

Therefore, in order to reduce the weight of the LED lighting device and secure the ease of handling and installation and safety, the material of the heat sink constituting the LED lighting device is light in weight and has substantially the same or superior mechanical properties to the metal material of the conventional heat sink. and a new material capable of implementing heat dissipation is in demand.

Korean Patent Publication No. 10-2014-0134041

The present invention has been devised to solve the above problems, and an object of the present invention is to provide a heat dissipating composite material that prevents fusion problems and process instability problems between heterogeneous fillers when alumina and carbon fibers are mixed with polyamide resin will do

In addition, an object of the present invention is to provide mixing process conditions for the optimal heat dissipation composite material production.

Another object of the present invention is to provide a heat dissipation composite material having high strength, light weight and high thermal conductivity, and a reflector for a projection lamp manufactured therefrom.

The heat dissipation composite material according to the present invention includes a polyamide resin, alumina (Al ₂ O ₃ ), carbon fiber, carbon nanotube (CNT) and additives as raw materials, and the total 100 of the composite material 40 to 45% by weight of the polyamide resin, 40% by weight of the alumina, 10 to 15% by weight of the carbon fiber, 2 to 3% by weight of the carbon nanotube, and 3 to 5% by weight of the additive based on the weight% do.

In addition, the alumina is characterized in that at least one selected from the group having a size of 15 ㎛, 30 ㎛ and 80 ㎛.

In addition, it is characterized in that 10 to 20% by weight of 15 μm alumina, 10 to 20% by weight of 30 μm alumina, and 60 to 80% by weight of 80 μm alumina based on 100% by weight of the total alumina.

In addition, the additive is at least one from the group consisting of compatibilizers, antioxidants, flow improvers, lubricants, dispersants, impact modifiers, flame retardant auxiliary plasticizers, heat stabilizers, anti-drip agents, light stabilizers, pigments, dyes, inorganic additives and anti-drip agents. characterized in that it is selected.

In addition, the composite material is manufactured by mixing the raw materials in a mixer satisfying a processing temperature of 280 to 300 ° C, a rotation speed of 500 to 530 RPM, a shear deformation of 50 to 55%, and the number of kneading blocks 10 to 20 do it with

In addition, the raw material is characterized in that batch input or side input into the mixer.

The reflector for a projection lamp according to the present invention is characterized in that it is obtained by processing the heat dissipation composite material.

According to the present invention, when alumina and carbon fibers are mixed with the polyamide resin, there may be an effect of preventing fusion problems and process instability problems between different fillers.

In addition, the effect of manufacturing a heat dissipation composite material having high strength, light weight and high thermal conductivity may occur by providing the mixing process conditions for the optimal heat dissipation composite material production.

In addition, the effect of providing a reflector for a projection lamp with excellent mechanical properties manufactured from a heat dissipation composite material may occur.

The present invention will be described in detail as follows. Here, repeated descriptions and detailed descriptions of well-known functions and configurations that may unnecessarily obscure the gist of the present invention will be omitted. The embodiments of the present invention are provided in order to completely explain the present invention to those of ordinary skill in the art.

Throughout the specification, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

Hereinafter, preferred examples are presented to help the understanding of the present invention. However, the following examples are only provided for better understanding of the present invention, and the content of the present invention is not limited by the examples.

The heat dissipation composite material according to the present invention may include a polyamide resin, alumina (Al ₂ O ₃ ), carbon fiber, carbon nanotube (CNT), and additives as raw materials.

The heat dissipation composite material according to the present invention may include a polymer resin as a base. Polymer resins are made of various engineering plastic materials such as polyamide (PA) resin, polybutylene terephthalate (PBT) resin, polyphenylene sulfide (PPS) resin, and polycarbonate (PC) resin. can be selected from However, PBT resin has a high instability due to the characteristics of the material, so when mixed with alumina, the physical properties of the heat-dissipating composite material decrease greatly. PPS resin has low impact strength due to the characteristics of the material itself. can In addition, the PC resin has a problem in that the strand is broken during the extrusion operation for manufacturing a molded product using a heat dissipation composite material including PC.

Therefore, as the heat dissipation composite material according to the present invention, a polyamide resin may be selected. Polyamide resin is a linear polymer material constituting a main chain by repeatedly connecting [-CONH-], an amide bond, and is also called nylon resin. It is a kind of engineering plastic and has excellent mechanical properties, especially impact resistance.

As the polyamide resin, aliphatic polyamide, semi-aromatic polyamide, aromatic polyamide, and mixtures thereof may be used.

The aliphatic polyamide can be prepared by ring-opening polymerization or polycondensation. The types of polyamides formed by ring-opening polymerization include polyamide 6 (PA6) having ε-caprolactam as a monomer, and polyamide 12 (PA12) having ω-laurolactam as a monomer. and polyamide 3 (PA3) having propano-3-lactam as a monomer. Examples of polyamides formed by polycondensation include ω-aminoenanthic acid. Polyamide 7 (PA7) having ω-aminoundecanoic acid as a monomer, polyamide 11 (PA11) having ω-aminoundecanoic acid as a monomer, hexamethylenediamine and adipic acid are polycondensed Polyamide 66 (PA66) Polyamide 46 (PA46) obtained by condensation polymerization of 1,4-diaminobutane and adipic acid and hexamethylenediamine and sebacic acid ( polyamide 610 (PA610) obtained by polycondensation of sebacic acid).

Semi-aromatic polyamide, also called polyphthalamide, is formed by polycondensation of terephthalic acid and isophthalic acid. Examples of the semi-aromatic polyamide include poly (hexamethylene teraphthalamide) (PA6T), poly (nonanmethylene teraphthalamide) (PA9T), and polyxylylene adipamide (PA-MXD6).

Aromatic polyamides may include aramids.

Preferably, polyamide 6 may be selected as the polyamide resin. Polyamide 6 does not show a significant decrease in physical properties at higher processing temperatures than other polyamides, and has a relatively low melting point, so it is easy to process and has excellent heat resistance and impact resistance.

The heat dissipation composite material according to the present invention may include an inorganic filler. As the inorganic filler, any one of alumina (Al ₂ O ₃ ), boron nitride (BN), aluminum nitride (AlN), and silicon nitride (Si ₃ N ₄ ) may be selected.

Preferably, alumina may be selected as the inorganic filler. Alumina has high thermal conductivity, and the effect of preventing the problem of fusion between heterogeneous fillers and the problem of mixing with polyamide resin may occur.

In this case, at least one alumina may be selected from the group having a size of 15 μm, 30 μm, and 80 μm. Table 1 shows the tensile strength and thermal conductivity of alumina by size.

Size (㎛) 10 15 20 30 50 80 Tensile strength (MPa) 61.8 62.8 61.8 62.9 62.2 61.2 Thermal conductivity (W/m·K) 0.95 1.03 1.02 1.06 1.09 1.13

Referring to Table 1, it was confirmed that alumina of 15 μm and 30 μm had the best tensile strength, and that the thermal conductivity increased as the size of alumina increased. If it is, it can have superior tensile strength and thermal conductivity than alumina of a single size. Table 2 shows the tensile strength and thermal conductivity of alumina having two sizes.

Size (㎛) 10+80 15+80 20+80 30+80 50+80 Tensile strength (MPa) 61.6 62.2 61.4 62.3 61.6 Thermal conductivity (W/m·K) 0.95 1.03 1.02 1.06 1.09

Referring to Table 2, it was confirmed that alumina having a size of 15+80 μm and 30+80 μm had the best tensile strength, and it was confirmed that the thermal conductivity increased as the size of alumina increased. Alumina can be used by mixing 15 μm and 30 μm alumina having excellent tensile strength and 80 μm alumina having the best thermal conductivity. Table 3 shows the tensile strength and thermal conductivity according to the mixing ratio of alumina having sizes of 15 μm, 30 μm and 80 μm.

mixing ratio
(15㎛:30㎛:80㎛) 10:30:60 10:20:70 10:10:80 20:10:70 20:40:40 33:33:34 40:40:20 60:30:10 The tensile strength
(MPa) 62 61.9 61.8 61.8 62.2 62.3 62.4 62.5 thermal conductivity
(W/m K) 1.13 1.17 1.16 1.16 1.09 1.05 1.03 1.01

Referring to Table 3, when 10 to 20% by weight of 15 μm alumina, 10 to 20% by weight of 30 μm alumina, and 60 to 80% by weight of 80 μm alumina based on 100% by weight of alumina total, it has the best tensile strength and thermal conductivity properties. that can be checked Preferably, it may be 10% by weight of 15 μm alumina, 20% by weight of 30 μm alumina and 70% by weight of 80 μm alumina.

The heat dissipation composite material according to the present invention may include carbon fibers as a fibrous filler.

Carbon fiber has a high specific surface area, excellent electrical conductivity, adsorption, etc., and can be obtained by growing a carbon material produced by decomposing and growing a gaseous compound containing carbon at a high temperature in the form of a fiber on a metal catalyst prepared in advance. Thermally decomposed carbons go through the stages of adsorption, decomposition, absorption, diffusion, and precipitation on the surface of a specific metal catalyst with a size of several nanometers, and are accumulated in the form of a graphene layer to form carbon fibers with excellent crystallinity and purity. have. Carbon fibers formed on catalyst particles of transition metals such as nickel, iron, cobalt, etc. grow to a nano level in diameter, which is 100 times thinner than that of other types of general-purpose carbon fibers with a diameter of 10 μm. It is more useful because it has a specific surface area and has excellent electrical conductivity, adsorption properties and mechanical properties.

As a method of synthesizing carbon fibers, there are mainly an electric discharge method, a laser deposition method, a plasma chemical vapor deposition method, and a chemical vapor deposition (CVD) method. Factors that affect the growth of carbon fibers include temperature, carbon source, catalyst, and the type of substrate. Among them, the difference between the diffusion action of the substrate and the catalyst particles and the interfacial action between them affects the shape and microstructure of the synthesized carbon fiber.

The heat dissipation composite material according to the present invention may include carbon nanotubes.

Carbon nanotubes are excellent in strength, modulus of elasticity, abrasion resistance, electrical conductivity and thermal conductivity, so they can be used as reinforcing materials for heat dissipation composite materials to supplement their physical properties.

The heat dissipation composite material according to the present invention may include an additive.

The additive may be at least one selected from the group consisting of compatibilizers, antioxidants, flow improvers, lubricants, dispersants, impact modifiers, flame retardant auxiliary plasticizers, heat stabilizers, anti-drip agents, light stabilizers, pigments, dyes, inorganic additives and anti-drip agents. . Preferably, compatibilizers, antioxidants, flow improvers and lubricants may be used as additives for the heat dissipation composite material.

The heat dissipation composite material according to the present invention contains 40 to 45 wt% of polyamide resin, 40 wt% of alumina, 10 to 15 wt% of carbon fiber, 2 to 3 wt% of carbon nanotubes, and 3 to 5 wt% of additives based on 100 wt% of the total It can be %.

The polyamide resin is a base material of the heat dissipation composite material, and may contain the largest amount of 40 to 45 wt% among all raw materials.

Alumina can be used in a ratio of 10:20:70 of three types of alumina of 15 μm, 30 μm and 80 μm, and the tensile strength and thermal conductivity by weight % of alumina with respect to 100 weight & total heat dissipation composite material are shown in Table 4 can be checked through

Alumina wt%
(15㎛:30㎛:80㎛=10:20:70) 30 35 40 45 50 Tensile strength (MPa) 90.2 87.5 81.2 67.1 61.9 Thermal conductivity (W/m·K) 0.81 0.95 1.12 1.14 1.17

Referring to Table 4, if the weight ratio of alumina is 35 wt% or less, there is a problem that the tensile strength increases but the thermal conductivity decreases. . Therefore, it can be confirmed that when alumina satisfies 40 wt% with respect to 100 wt% of the total heat dissipation composite material, it has appropriate tensile strength and thermal conductivity properties at the same time. Carbon fiber is added to increase the mechanical properties and thermal conductivity of the heat dissipation composite material. , the tensile strength and thermal conductivity by weight % of carbon fiber can be confirmed through Table 5.

Carbon Fiber Weight % 5 10 15 20 Tensile strength (MPa) 106 126 138 156 Thermal conductivity (W/m·K) 1.29 1.36 1.41 1.43 Density (g/cm ³ ) 1.98 2.01 2.05 2.09

Referring to Table 5, it can be confirmed that carbon fiber has appropriate tensile strength, thermal conductivity, and density characteristics at the same time when carbon fiber satisfies 10 to 15% by weight with respect to 100% by weight of the total heat dissipation composite material. Carbon nanotubes have thermal conductivity of the heat dissipation composite material It is added to increase the , and the tensile strength and thermal conductivity by weight % of carbon nanotubes can be confirmed through Table 6.

Carbon nanotube wt% 0 0.5 One 2 3 Thermal conductivity (W/m·K) 1.36 1.45 1.51 1.63 1.64

Referring to Table 6, it can be seen that the thermal conductivity is increased when the carbon nanotube content satisfies 2 to 3 wt% with respect to 100 wt% of the total heat dissipation composite material. The additive may include a compatibilizer, an antioxidant, a flow improver and a lubricant. , 3 to 5% by weight of additives may be included with respect to 100% by weight of the total heat dissipation composite material.

The compatibilizer is added to increase the mechanical strength of the heat dissipation composite material, and the physical properties by weight% of the compatibilizer can be confirmed through Table 7.

Compatibilizer wt% 0 One 2 3 5 Tensile strength (MPa) 126 129 132 141 142 Flexural strength (MPa) 185 192 196 206 209 Impact strength (MPa) 45 54 63 72 75 Flexural modulus (J/m) 7006 7123 7211 7856 8123 Density (g/cm ³ ) 2.01 2.02 2.02 2.03 2.04 Hardness 116 116 116 117 116 Thermal conductivity (W/m·K) 1.36 1.45 1.51 1.63 1.64

Referring to Table 7, it can be seen that the mechanical strength is greatly improved when 3 wt% or more of the compatibilizer is added. The antioxidant may be added in a small amount within 0.5 wt% to prevent oxidation of the heat dissipating composite material.

The flow improving agent and lubricant may be added to improve the fluidity of the raw material inside the mixer when manufacturing the heat dissipation composite material, and may be added in small amounts within 0.5 wt%, respectively.

In one embodiment of the present invention, the heat dissipation composite material may include 43.7 wt% of polyamide resin, 40 wt% of alumina, 10 wt% of carbon fiber, 2 wt% of carbon nanotubes, and 4.3 wt% of additives, and alumina 15 Three kinds of alumina of ㎛, 30 ㎛, and 80 ㎛ size are made in a ratio of 10:20:70, and the additive contains 3% by weight of compatibilizer, 0.3% by weight of antioxidant, 0.5% by weight of flow improver and 0.5% by weight of lubricant. can At this time, the physical properties of the heat dissipation composite material satisfy the tensile strength of 136 Mpa, the flexural strength of 195 Mpa, the impact strength of 65 MPa, the flexural modulus of 7842 J/m, the density of 2.03 g/cm ³ , the hardness of 116 and the thermal conductivity of 1.63 W/m K. can

The heat dissipation composite material according to the present invention is obtained by mixing the raw materials in a mixer that satisfies a processing temperature of 280 to 300 ° C, a rotation speed of 500 to 530 RPM, a shear strain of 50 to 55%, and the number of kneading blocks 10 to 20. can be manufactured.

The mixer can mix and manufacture the heat dissipating composite material by supplying the raw material to a commonly known melt mixer such as a single screw or twin screw extruder, a Banbury mixer, a kneader, and a mixing roll. At this time, the raw materials may be batch-injected into the mixer or side-injected, and the difference in physical properties between the two inputs is almost the same, and there is a difference only in the order of operations. In the case of batch input of raw materials, preparation time is shortened and additional calibration is not required due to side input. When raw materials are side-injected, polyamide resin, alumina and additives are side-injected, and carbon fibers and carbon nanotubes are put into main to reduce polarization between raw materials so that the heat dissipation composite material can be mixed evenly, The advantage is that mixing is performed only once.

The heat dissipation composite material may be mixed with the raw material at a processing temperature of 280 to 300 °C. If the processing temperature is less than 280 ℃ or exceeds 300 ℃, the tensile strength may decrease. The heat-dissipating composite material can show the highest tensile strength when processed at a processing temperature of 290 ℃.

The heat dissipation composite material may be mixed with a raw material in a mixer with a rotation speed of 500 to 530 RPM. If the rotational speed is less than 500 RPM, the tensile strength may decrease, and if it exceeds 530 RPM, the increase in tensile strength is reduced, so that there is little difference in tensile strength.

The heat dissipation composite material can be mixed with the raw material under the condition of 50 to 55% shear strain. Shear deformation is sliding deformation due to angular change caused by shear force. If the shear deformation is less than 50%, the tensile strength may decrease, and if it exceeds 55%, the mixer may stop.

The heat dissipation composite material may be mixed with a raw material in a mixer having 10 to 20 kneading blocks. If the number of kneading blocks is less than 10, the dispersibility of the heat dissipation composite material decreases, and there is a problem in that single yarn frequently occurs due to poor workability. If the number of kneading blocks exceeds 20, there may be a problem that the productivity of the heat dissipation composite material decreases.

A reflector for a projection lamp can be molded using the heat dissipation composite material according to the present invention. The reflector for the projection lamp may be molded using die-casting.

Although described with reference to the preferred embodiment of the present invention, those of ordinary skill in the art can variously modify and change the present invention within the scope without departing from the spirit and scope of the present invention described in the claims below. You will understand that it can be done.

Claims (7)

In the composite material containing polyamide resin, alumina (Al ₂ O ₃ ), carbon fiber, carbon nanotube (CNT) and additives as raw materials,
The composite material may include 40 to 45% by weight of the polyamide resin, 40% by weight of the alumina, 10 to 15% by weight of the carbon fiber, 2 to 3% by weight of the carbon nanotube, and 3 to 5% by weight of the polyamide resin based on 100% by weight of the total characterized in that the weight %,
Heat dissipation composite material.
The method of claim 1,
The alumina
Characterized in that at least one selected from the group having a size of 15 μm, 30 μm and 80 μm,
Heat dissipation composite material.
3. The method of claim 2,
15 μm alumina 10 to 20 wt%, 30 μm alumina 10 to 20 wt%, and 80 μm alumina 60 to 80 wt% based on 100 wt% of the total alumina,
Heat dissipation composite material.
The method of claim 1,
The additive is
Compatibilizers, antioxidants, flow improvers, lubricants, dispersants, impact modifiers, flame retardants, plasticizers, heat stabilizers, anti-drip agents, light stabilizers, pigments, dyes, inorganic additives and anti-drip agents, characterized in that at least one selected from the group consisting of ,
Heat dissipation composite material.
The method of claim 1,
The composite material is
It is characterized in that it is prepared by mixing the raw materials in a mixer satisfying a processing temperature of 280 to 300 ° C, a rotation speed of 500 to 530 RPM, a shear deformation of 50 to 55% and the number of kneading blocks 10 to 20,
Heat dissipation composite material.
6. The method of claim 5,
The raw material is
Characterized in that batch input or side input to the mixer,
Heat dissipation composite material.
A reflector for a projection lamp obtained by processing the heat dissipation composite material according to claim 1 .