CN101316499A - Heat dissipation substrate and heat dissipation material thereof - Google Patents

Abstract

A heat dissipating material comprising: (1) the fluorine-containing high molecular polymer has a melting point higher than 150 ℃ and the weight percentage between 15 and 40 percent; (2) the heat-conducting filler is dispersed in the fluorine-containing high molecular polymer, and the weight percentage of the heat-conducting filler is between 60 and 85 percent; and (3) a coupling agent in a proportion of 0.5 to 3% by weight of the thermally conductive filler. The chemical formula of the coupling agent is shown in the figure, wherein R1, R2 and R3 are alkyl C_aH_2a+1A is more than or equal to 1; x and Y are selected from: hydrogen , fluorine (F), chlorine (Cl), C_bH_2b+1B is not less than 1; and n is a positive integer.

Description

Heat dissipation substrate and its heat dissipation material

technical field

The invention relates to a heat dissipation substrate and its heat dissipation material, in particular to a heat dissipation substrate for electronic components and its material.

Background technique

Except for actual work, most of the electric energy consumed by electronic components during operation is converted into heat and dissipated. The heat generated by electronic components makes the internal temperature rise rapidly. If the heat is not dissipated in time, the components will continue to heat up or even fail due to overheating, and the reliability of electronic components will decline.

Surface mount technology (SMT) increases the mounting density of electronic components on the printed circuit board (PCB), reduces the effective heat dissipation area, and increases the temperature of the components, which will seriously affect the reliability. In particular, the high heat problem of white light-emitting diodes (LEDs), which is currently the most promising and attracts the most global attention, will cause the temperature of the LED components to be too high and affect its luminous intensity and service life. Therefore, thermal design is very important.

Whether it is a display backlight or general lighting, it is common to assemble multiple LED components on a circuit substrate. In addition to playing the role of carrying the LED module, the circuit substrate also provides the function of heat dissipation.

Conventional PCB boards with copper foil on the surface of glass fiber FR4 have a heat dissipation coefficient of about 0.3W/m-K, which is not enough to meet the heat dissipation requirements. In addition, the heat dissipation substrate using FR4 as the base material has poor flexibility and is not suitable for the application of foldable products.

Contents of the invention

The main purpose of the present invention is to provide a heat dissipation substrate, which has excellent heat dissipation characteristics, and has both high voltage resistance dielectric insulation characteristics and flexible mechanical structure characteristics, so as to provide such as PCB boards as carrying electronic components (such as LED high power components) cooling applications.

The invention discloses a heat dissipation substrate and its heat dissipation material. The heat dissipation substrate includes a first metal foil, a second metal foil and a heat dissipation material layer. The heat dissipation material layer is stacked between the first metal foil and the second metal foil and forms physical contact. The thermal conductivity of the heat dissipation material layer is greater than 1.0W/m-K, and the thickness is less than 0.5mm, and the heat dissipation material therein includes: (1) a fluorine-containing high molecular polymer, whose melting point is higher than 150°C, and the weight percentage is between 15- between 40%; (2) thermally conductive filler, which is dispersed in the fluorine-containing high molecular polymer, and the weight percentage is between 60-85%; and (3) coupling agent, whose ratio is that of the thermally conductive filler 0.5-3% by weight. The chemical formula of the coupling agent is

Wherein, R1, R2 and R3 are alkyl group C _a H _2a+1 , a≥1;

X and Y are selected from: hydrogen (H), fluorine (F), chlorine (Cl), C _b H _2b+1 , b≥1; and

n is a positive integer.

Preferably, the fluorine-containing polymer can be selected from ethylene-tetrafluoroethylene copolymer (polyethylenetetrafluoroethylene; PETFE) or polyvinylidene fluoride (Poly Vinylidene Fluoride; PVDF), wherein the melting point of PETFE is greater than 220 ° C, the melting point of PVDF The melting point is greater than 150°C. Because both have a high melting point and are flame retardant, they can withstand high temperatures and are not easy to catch fire, so they have more safety application value. The thermally conductive filler can be selected from ceramic thermally conductive materials such as nitrides and oxides.

In addition to having good heat conduction and insulation effects, if the thicknesses of the first metal foil and the second metal foil are respectively made less than 0.1mm and 0.2mm, and the thickness of the heat dissipation material layer is less than 0.5mm (0.3mm is better ), which can be used for foldable product applications by bending a 1cm-wide test substrate into a 10mm-diameter circular flexure test, and there will be no breaks or cracks on the surface.

Description of drawings

FIG. 1 illustrates a heat dissipation substrate according to one embodiment of the present invention.

Detailed ways

The heat dissipation material of the present invention mainly includes: a fluorine-containing high molecular polymer, a thermally conductive filler and a coupling agent, and the components, proportions and production methods thereof are described in detail as follows.

The surface of the heat dissipation material of the present invention can be attached with a metal foil to make a heat dissipation substrate. The manufacturing method is as follows: (1) pour 24 parts of fluorine-containing high molecular polymer and 76 parts of thermal conductive filler and coupling agent into a ball mill tank, and mixed at 100 rpm for 12 hours. That is, the weight ratio of the fluorine-containing polymer to the thermally conductive filler was 24:76. (2) Pour the above-mentioned premixed raw materials into the kneader (the oil temperature is set at 240°C) and knead at 45rpm, and complete the mixing at about 270°C after the raw materials are melted evenly. (3) Pour the molten raw material completed by the kneader into a pelletizer, and cut it into small particles at 300°C for later use. (4) Pour the above-mentioned completed particles into a twin-screw extruder to extrude a thin sheet at 280°C, and then laminate a metal foil (such as copper foil) on a calender to complete the heat dissipation substrate 10 (thickness containing metal foil) as shown in Figure 1. foil is about 0.27mm).

Specifically, the heat dissipation substrate 10 includes a first metal foil 11, a second metal foil 12, and a heat dissipation material layer 13 stacked between the first metal foil 11 and the second metal foil 12. The heat dissipation material layer 13 is made of the above-mentioned heat conduction material. The interface between the first and second metal foils 11 and 12 and the heat dissipation material layer 13 forms a physical contact, and the inner surface of the metal foils 11 and 12 has knob-like protrusions and is bonded to the heat dissipation material layer 13 Create adhesion.

The above-mentioned fluorine-containing polymer can be ethylene-tetrafluoroethylene copolymer (PETEF) or polyvinylidene fluoride (PVDF). This embodiment uses PETFE, such as Q3-9030 or Tefzel ^™ from Dow Chemical Company. Thermally conductive fillers can be oxides or nitrides. The coupling agent is 0.5-3% by weight of the thermally conductive filler, and its chemical formula is:

Wherein, R1, R2 and R3 are alkyl group C _a H _2a+1 , a≥1;

X and Y are selected from: hydrogen (H), fluorine (F), chlorine (Cl), C _b H _2b+1 , b≥1; and

n is a positive integer.

In order to clearly understand the characteristics of the present invention after adding the coupling agent, without adding the coupling agent and changing the mixing time in the ball mill tank to 20 minutes, the comparison group was made in the same way, while adding different proportions of the coupling agent Combined experimental group for comparison. The test results of withstand voltage and flexibility are shown in Table 1.

The withstand voltage test is a pressure cooking test (Pressure Cook Test; PCT), which is to test the prepared test piece after 24 hours under the saturated vapor pressure of 2 atmospheric pressure (atm) and 121 °C. If the prepared test piece is not dense enough, the intruded water vapor will damage its withstand voltage characteristics. The flexibility test is to remove the 1cm-wide sheet foil of the second metal foil from the formed material, which is equivalent to the minimum diameter that can be bent into a circle without breaking if only a single side of the copper foil is attached.

Table I

It can be seen from Table 1 that the withstand voltage characteristics of the control group without coupling agent after the pressure cooking test were significantly lower than those at the initial stage (without pressure cooking), while the experimental groups 1-5 with the addition of coupling agent were still the same after the pressure cooking test. It can withstand a considerable voltage (>2KV), and the weight percentage of the coupling agent as the thermal conductive filler is preferably between 0.75-1.5%, and has good withstand voltage characteristics. In addition, the cracked diameters of the specimens in the bending test of all experimental groups 1-5 were less than 10mm, and improved significantly with the increase of the coupling agent ratio, which was significantly better than that without the addition of coupling agent (> 10mm). In other words, more coupling agent will make the constituent material softer and have better flex properties.

The weight percentages of the fluorine-containing high molecular polymer and the thermally conductive filler can be adjusted to some extent while still maintaining the same characteristics. Preferably, the weight percentage of the fluorine-containing high molecular polymer is between 15-40%; and the weight percentage of the thermally conductive filler is between 60-85%. The coupling agent is 0.5-3% by weight of the thermally conductive filler.

In addition to the above material selection, thermally conductive polymers can also be polytetrafluoroethylene (poly(tetrafluoroethylene); PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (tetrafluoroethylene-hexafluoro-propylene copolymer; FEP), ethylene- Tetrafluoroethylene copolymer (ethylene-tetrafluoroethylene copolymer; ETFE), perfluoroalkoxy modified tetrafluoroethylene (PFA), poly (chlorotri-fluorotetrafluoroethylene) (poly (chlorotri-fluorotetrafluoroethylene); PCTFE), vinylidene fluoride-tetrafluoroethylene copolymer (vinylidene fluoride-tetrafluoroethylene copolymer); VF-2-TFE), polyvinylidene fluoride (poly(vinylidene fluoride)), tetrafluoroethylene-perfluoromethylene dioxide Tetrafluoroethylene-perfluorodioxole copolymers, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer (vinylidene fluoride- Hexafluoropropylene-tetrafluoroethylene terpolymer) and tetrafluoroethylene-perfluoromethylvinyl ether (tetrafluoroethylene-perfluoromethylvinylether) plus cure site monomer terpolymer (cure site monomer terpolymer), etc.

The nitrides selected for the thermally conductive filler include zirconium nitride (ZrN), boron nitride (BN), aluminum nitride (Aluminum nitride; AlN), and silicon nitride (Silicon nitride; SiN). Oxides include aluminum oxide (Aluminum oxide; Al ₂ O ₃ ), magnesium oxide (Magnesium oxide; MgO), silicon oxide (Silicon oxide; SiO ₂ ), zinc oxide (Zinc oxide; ZnO), titanium dioxide (Titaninum dioxide; TiO ₂ )wait.

The thermal conductivity of the heat dissipation material of the present invention is greater than 1.0W/m-K, generally even greater than 1.5W/m-K, and compared with traditional FR4 glass fiber, its heat dissipation efficiency can be greatly improved.

The heat dissipation material of the present invention not only has high thermal conductivity and high voltage resistance, but also the heat dissipation substrate produced by it has excellent flexibility, so it can be applied to current PCBs for heat dissipation of LED modules for lighting, and can even be used in notebooks Computer, mobile phone and other folding heat dissipation applications.

The technical content and technical features of the present invention have been disclosed above, but those skilled in the art may still make various replacements and amendments without departing from the spirit of the present invention based on the teaching and disclosure of the present invention. Therefore, the protection scope of the present invention should not be limited to those disclosed in the embodiments, but should include various replacements and modifications that do not depart from the present invention, and are covered by the appended claims.

Claims (16)

1. heat sink material, its conductive coefficient is characterized in that comprising greater than 1.0W/m-K:

Fluoro containing polymers polymer, its fusing point are higher than 150 ℃;

Heat filling, it intersperses among in the described fluoro containing polymers polymer; And

Coupling agent, its chemical formula is

Wherein, R1, R2 and R3 are alkyl C _aH _2a+1, a 〉=1;

X and Y are selected from: H, F, Cl, C _bH _2b+1, b 〉=1;

N is a positive integer.

2. heat sink material according to claim 1, the percentage by weight that it is characterized in that described heat filling is between 60-85%, percentage by weight Jie 15-40% of described fluoro containing polymers polymer, described coupling agent are the 0.5-3% percentage by weight of heat filling.

3. heat sink material according to claim 1 is characterized in that described fluoro containing polymers polymer is selected from ethylene-tetrafluoroethylene copolymer or polyvinylidene fluoride.

4. heat sink material according to claim 1 is characterized in that described fluoro containing polymers polymer is selected from polytetrafluoroethylene, tetrafluoraoethylene-hexafluoropropylene copolymer, ethylene-tetrafluoroethylene copolymer, perfluoro alkoxy upgrading tetrafluoroethene, poly-(chlorine three-fluorine tetrafluoroethene), vinylidene fluoride-TFE copolymer, polyvinylidene fluoride, tetrafluoroethene-perfluor dioxole copolymer, vinylidene difluoride-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethene trimer and tetrafluoroethene-perfluoro methyl vinyl ether add and solidify territory monomer trimer.

5. heat sink material according to claim 1 is characterized in that described coupling agent is 0.75～1.5% percentage by weight of described heat filling.

6. heat sink material according to claim 1 is characterized in that described heat filling is selected from nitride or oxide.

7. heat sink material according to claim 6 is characterized in that described oxide is selected from aluminium oxide, magnesium oxide, silica, zinc oxide, titanium dioxide.

8. heat sink material according to claim 6 is characterized in that described nitride is selected from zirconium nitride, boron nitride, aluminium nitride, silicon nitride.

9. heat-radiating substrate is characterized in that comprising:

First metal forming;

Second metal forming; And

The radiative material bed of material, it is stacked and placed between described first metal forming and described second metal forming and forms physics and contacts,

The conductive coefficient of the described radiative material bed of material is greater than 1W/m-K, and thickness is less than 0.5mm, and comprises:

(1) fluoro containing polymers polymer, its fusing point are higher than 150 ℃; With

(2) heat filling, it intersperses among in the described fluoro containing polymers polymer; And

(3) coupling agent, its chemical formula is

Wherein, R1, R2 and R3 are alkyl C _aH _2a+1, a 〉=1;

X and Y are selected from: H, F, Cl, C _bH _2b+1, b 〉=1;

N is a positive integer.

10. heat-radiating substrate according to claim 9, the percentage by weight that it is characterized in that described heat filling is between 60-85%, percentage by weight Jie 15-40% of described fluoro containing polymers polymer, described coupling agent are the 0.5-3% percentage by weight of heat filling.

11. heat-radiating substrate according to claim 9 is characterized in that described fluoro containing polymers polymer is selected from ethylene-tetrafluoroethylene copolymer or polyvinylidene fluoride.

12. heat-radiating substrate according to claim 9 is characterized in that described fluoro containing polymers polymer is selected from polytetrafluoroethylene, tetrafluoraoethylene-hexafluoropropylene copolymer, ethylene-tetrafluoroethylene copolymer, perfluoro alkoxy upgrading tetrafluoroethene, poly-(chlorine three-fluorine tetrafluoroethene), vinylidene fluoride-TFE copolymer, polyvinylidene fluoride, tetrafluoroethene-perfluor dioxole copolymer, vinylidene difluoride-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethene trimer and tetrafluoroethene-perfluoro methyl vinyl ether add and solidify territory monomer trimer.

13. heat-radiating substrate according to claim 9 is characterized in that described heat filling is selected from: aluminium oxide, magnesium oxide, zinc oxide, silica, titanium dioxide, zirconium nitride, boron nitride, aluminium nitride and silicon nitride.

14. heat-radiating substrate according to claim 9, after it is characterized in that adopting the wide heat-radiating substrate of 1cm and removing described second metal forming, surface non-cracking or slight crack produce when song becomes the cylinder of 10mm diameter, and the thickness of wherein said first metal forming is smaller or equal to 0.2mm.

15. heat-radiating substrate according to claim 9 is characterized in that placing 2 atmospheric pressure, the boiling of 121 ℃ of saturated steam pressure after 24 hours, every 2mm can bear the above voltage of 2KV.

16. heat-radiating substrate according to claim 9 is characterized in that described first and second metal formings are Copper Foils.

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