A kind of high-heat-conductive composite material and preparation method thereofTechnical field
The present invention relates to a kind of technical field of polymer materials, particularly relate to and a kind ofly be used to inject or the high heat conduction plastic composites of extrusion moulding and preparation method thereof.
Technical background
Because metallic substance has good heat-conducting, the most applied metal material of traditional heat exchange and heat sink material, but metallic substance easy conductive, weight height, mechanical workout complexity.Along with technical progress and industrial upgrading, in increasing Application Areas such as electronic information, Thermal Power Engineering, require material to have characteristics such as light, easy processing, insulation, these requirements make technologic material be difficult to be competent at.Macromolecular material has good processing properties, easily by injection or extrusion moulding.But macromolecular material is the poor conductor of heat mostly, and thermal conductivity is compared usually with metallic substance and differed more than hundreds of times.Some Application Areass have proposed more and more higher requirement to the heat conductivility of macromolecular material, shell as the encapsulation of CPU and LED and heat radiation, unicircuit and multilayer circuit board, power device, these materials all require heat conductive insulating, make heat-conducting polymer material particularly the research of heat conduction plastic material be subjected to extensive concern.
Existing studies show that, the approach of raising macromolecular material heat conductivility mainly contains the polymkeric substance of synthetic high thermal conductivity coefficient and by high heat conduction inorganics polymkeric substance is filled.The former mainly improve heat transfer property by the electronics thermal conduction mechanism, but thermal conductivity still is lower than 1.0W/mK usually as polyacetylene with good heat conductive performance, polyaniline, polypyridine etc., and it costs an arm and a leg and differs greatly with the metal heat-conducting performance.Therefore, the research of preparation high molecular polymer/inorganics heat-conductive composite material and application are more extensive.
Heat conductive filler commonly used comprises following type substantially: 1) metal powder filler, and as copper powder, aluminium powder etc., but when being arranged, insulating requirements do not use usually; 2) metal oxide is as aluminum oxide, magnesium oxide, zinc oxide etc.; 3) metal nitride is as aluminium nitride, boron nitride etc.; 4) inorganic non-metallic is as graphite, silicon carbide etc.In addition, in order to form successive heat conduction network chain, materials such as carbon fiber, glass fibre, silicon whisker also usually are selected as fills combination.The heat conductivility of high molecular polymer/inorganics heat-conductive composite material not only depends on kind, the characteristic of polymeric matrix and heat conductive filler, and with shape, particle diameter, the distribution of sizes of filler, the interface binding characteristic of filler and matrix is closely related.
Chinese patent 200510101700.0 discloses a kind of injection molding moulded heat-conductive insulated plastics, provide a kind of heat conductive filler based on macrobead heat conductive filler, the combination of employing different-grain diameter to prepare moulded heat-conductive insulated plastics by injection molding, its thermal conductivity of narration can reach 1.9～3.5W/mK in the patent.But, the inventor studies show that: the filler and the plastic substrate of different-grain diameter are mixed together, the filler of small particle size is easier of the plastic pellet surface, cause the filler of big particle diameter to mix inhomogeneous with plastic pellet, not high through heat conductive filler density behind the twin screw extruder extruding pelletization, also be not easy to form successive heat conduction network chain.And the loading level of mineral filler makes the injection moulding processing characteristics of material be subjected to having a strong impact on usually up to 70%.Chinese patent 200710024620.9 discloses a kind of moulded heat-conductive insulated plastics and manufacture method thereof, by adding the combination of multiple small particle size mineral filler, improve the high heat dispersion of electrical equipment crust of the device, its thermal conductivity of narration can reach 6～18W/mK in the patent.Chinese patent 200710076484.8 discloses a kind of highly heat conductive polyphenylene sulfide composite material and preparation method thereof, adopts heat conductive filler, glass etc. as weighting material, and its thermal conductivity of narration can reach 13.5W/mK in the patent.But, do not disclose the particle diameter of the heat conductive filler that uses in this patent, and the inventor studies show that for the multiple plastic material that comprises polyphenylene sulfide, the size distribution of employing filler has material impact for material property.
In addition, external report has the high heat-conducting plastic of polyphenylene sulfide, and thermal conductivity is up to 25～100W/mK, but does not see and disclose its prescription and preparation method.
Summary of the invention
The technical problem to be solved in the present invention is to provide a kind of high heat conduction plastic composites and preparation method thereof, makes the material of preparation have good heat-conducting and injection moulding processing characteristics.
The invention provides a kind of high-heat-conductive composite material, it forms by the quality proportioning is (part):
Plastic material 100;
50～300 microns big particle diameter heat conductive fillers 30～100;
1-10 micron small particle size heat conductive filler 0～50;
Glass fibre, silicon whisker or carbon fiber 10～50;
Coupling agent 0～5;
Auxiliary agent 0～8.
Wherein, described plastic material is that among PPS, PP, PE, PS or the ABS one or more are compound.
Wherein, described heat conductive filler is that in metal oxide, metal nitride, graphite, the silicon carbide one or more are compound.Especially, described big particle diameter heat conductive filler and small particle size heat conductive filler are two kinds of different substancess, can obtain better heat conductivility.
Wherein, described glass fibre is non-twist roving glass fiber of alkali-free or alkali-free short glass fiber, and described carbon fiber is the carbon fiber textile spent material.
Wherein, described coupling agent is silane coupling agent, titanate coupling agent or titanium aluminate coupling agent.
Wherein, described auxiliary agent is stearic amide, stearate, boron nitride or molybdenumdisulphide.
Preferred version of the present invention is as follows: a kind of composition of high-heat-conductive composite material by the quality proportioning is 20～40 parts of 50～80 parts, 1～10 micron small particle size heat conductive fillers of 100 parts, 50～300 microns big particle diameter heat conductive fillers of plastic material, 20～40 parts in glass fibre, 0.1～2 part of coupling agent, 0.1～2 part of lubricant.Described plastic material is PS, ABS or PPS, and big particle diameter heat conductive filler is aluminum oxide or aluminium nitride, and the small particle size heat conductive filler is magnesium oxide or silicon carbide.
The preparation method of a kind of high-heat-conductive composite material that the present invention proposes may further comprise the steps:
1) 0.5～3% of its quality of adding coupling agent carries out surface treatment, 30～80 ℃ of treatment temps, treatment time 5～10min in the small particle size heat conductive filler that takes by weighing by the quality proportioning;
2) 0.5～3% of its quality of adding coupling agent carries out surface treatment, 30～80 ℃ of treatment temps, treatment time 5～15min in the big particle diameter heat conductive filler that takes by weighing by the quality proportioning;
3), drop into big particle diameter heat conductive filler, other auxiliary agent of handling well and to mix 1～5min in the super mixer at the plastic material that takes by weighing by the quality proportioning;
4) in super mixer, add the small particle size heat conductive filler of handling well again, mix 2～3min;
5) above-mentioned mixed raw materials is put into the loading hopper of twin screw extruder, glass fibre joins the glass mouth of twin screw extruder, through melt extruding granulation.
High-heat-conductive composite material provided by the present invention and preparation method thereof, cost is lower, and technology is simple, and prepared material has good heat-conducting and processing characteristics, can mold pressing, extrude or injection molding.
Embodiment
The invention provides a kind of high-heat-conductive composite material, the parts by weight consumption of each component is as follows: 0～50 part of 30～100 parts, 1～10 micron small particle size heat conductive filler of 100 parts, 50～300 microns big particle diameter heat conductive fillers of plastic substrate, 10～50 parts in glass fibre, 0～5 part of coupling agent, 0～8 part of auxiliary agent.
Wherein, described plastic material is that among PPS, PP, PE, PS or the ABS one or more are compound, described heat conductive filler is that in metal oxide, metal nitride, graphite, the silicon carbide one or more are compound, described glass fibre is non-twist roving glass fiber of alkali-free or alkali-free short glass fiber, described coupling agent is silane coupling agent, titanate coupling agent or titanium aluminate coupling agent, and described auxiliary agent is stearic amide, stearate, boron nitride or molybdenumdisulphide.Especially, described big particle diameter heat conductive filler and small particle size heat conductive filler are two kinds of different substancess, can obtain better heat conductivility.
Embodiment 1:
A kind of composition of high-heat-conductive composite material by the quality proportioning is: 100 parts of PPS, 25 parts of 60 parts, 2 microns silicon carbide small particle size heat conductive fillers of the big particle diameter heat conductive filler of 200 micrometer aluminas, 25 parts in glass fibre, 0.5 part of aluminate coupling agent, 0.5 part of molybdenum disulfide lubricant.
Its preparation method is as follows:
1) in 200 micrometer aluminas that take by weighing by the quality proportioning, adds coupling agent and carry out surface treatment, 30～80 ℃ of treatment temps, treatment time 5～10min;
2) in 2 microns silicon carbide that take by weighing by the quality proportioning, add coupling agent and carry out surface treatment, 30～80 ℃ of treatment temps, treatment time 4～8min;
3), drop into 200 micrometer aluminas, the molybdenum disulfide lubricant handled well and to mix 3～5min in the super mixer at the polyphenyl thioether material that takes by weighing by the quality proportioning;
4) in super mixer, add 2 microns silicon carbide handling well again, mix 2～3min;
5) above-mentioned mixed raw materials is put into the loading hopper of twin screw extruder, joined the glass mouth of twin screw extruder by the glass fibre of quality proportioning, through melt extruding granulation.The forcing machine design temperature is 250～300 ℃, and the residence time is 2～3min, and pressure is 100～200MPa.
Embodiment 2:
A kind of composition of high-heat-conductive composite material by the quality proportioning is: 30 parts of 80 parts, 5 microns aluminium nitride of 100 parts, 300 microns magnesium oxide of PP, 20 parts on carbon fiber, 0.5 part of aluminate coupling agent, 0.5 part of molybdenum disulfide lubricant.Its preparation method is identical with embodiment one.
Example 3:
A kind of composition of high-heat-conductive composite material by the quality proportioning is: 100 parts of PP, 60 parts of the big particle diameter heat conductive fillers of 200 micrometer aluminas, 5 25 parts of micrometer alumina small particle size heat conductive fillers, 25 parts in glass fibre, 0.5 part of coupling agent, 0.5 part of lubricant.Its preparation method is identical with embodiment one.
Example 4:
A kind of composition of high-heat-conductive composite material by the quality proportioning is: 100 parts of PP, 60 parts of the big particle diameter heat conductive fillers of 200 micrometer aluminas, 5 25 parts of micrometer alumina small particle size heat conductive fillers, 0.5 part of coupling agent, 0.5 part of lubricant.Its preparation method is identical with embodiment one.
Example 5:
A kind of composition of high-heat-conductive composite material by the quality proportioning is: 100 parts of PP, 60 parts of the big particle diameter heat conductive fillers of 200 micrometer aluminas, 25 parts in glass fibre, 0.5 part of coupling agent, 0.5 part of lubricant.Its preparation method is identical with embodiment one.
According to the thermal conductivity of GB/T 3139-2005 standard testing PP, PPS and embodiment 1～5, the result is as shown in table 1.
Table 1: thermal conductivity test result (unit: W/mK)
| Numbering | ??PP | ??PPS | Embodiment 1 | Embodiment 2 | Example 3 | Example 4 | Example 5 |
| Thermal conductivity | ??0.2 | ??0.3 | ?3.7 | ?3.4 | ??3.1 | ??2.6 | ??1.9 |
Test result shows that the present invention compared with prior art has following advantage:
1, adopts different types of large particle diameter and small particle diameter heat filling composite, and go on foot the even distribution that mixing preparation methods have improved plastic pellet and size particles by two;
2, improve the continuity of heat conduction network by glass or carbon fiber, particularly effectively improved the heat conduction directionality of existing heat-conducting plastic;
3, cost is lower, and technique is simple, and prepared material has good heat conductivility and processing characteristics, can mold pressing, extrude or injection moulding.