LCPU modified epoxy resin-based heat-conducting composite material and preparation method and application thereof
阅读说明：本技术 一种lcpu改性环氧树脂基导热复合材料及其制备方法和应用 (LCPU modified epoxy resin-based heat-conducting composite material and preparation method and application thereof ) 是由 张东宝 于冉 徐良 于 2021-08-05 设计创作，主要内容包括：本发明涉及液晶高分子材料技术领域,公开了一种LCPU改性环氧树脂基导热复合材料及其制备方法和应用。该方法包括以下步骤：(1)制备4,4’-二(5-羟基戊烷氧基)联苯；(2)液晶聚氨酯改性导热填料；(3)制备LCPU改性环氧树脂基导热复合材料。本发明将经过液晶聚氨酯改性后的填料与环氧树脂混合,能够构建一种连续的导热网络,从而提高材料的导热率。(The invention relates to the technical field of liquid crystal polymer materials, and discloses an LCPU modified epoxy resin-based heat-conducting composite material and a preparation method and application thereof. The method comprises the following steps: (1) preparing 4, 4' -bis (5-hydroxypentanyloxy) biphenyl; (2) liquid crystal polyurethane modified heat-conducting filler; (3) preparing the LCPU modified epoxy resin-based heat-conducting composite material. According to the invention, the filler modified by the liquid crystal polyurethane is mixed with the epoxy resin, so that a continuous heat conduction network can be constructed, and the heat conductivity of the material is improved.)
1. A method for preparing LCPU modified epoxy resin-based heat-conducting composite material is characterized by comprising the following steps:
(1) in the presence of a solvent I, carrying out a first contact reaction on an initiator, 4 '-dihydroxybiphenyl and alcohol, and carrying out a first drying treatment on a product obtained by the first contact reaction to obtain 4, 4' -bis (5-hydroxypentanyloxy) biphenyl; the molecular formula of the alcohol is Cl- (CH)2)nOH, wherein n is an integer of 3-8;
(2) in the presence of a solvent II, carrying out a second contact reaction on a heat-conducting filler and a first part of toluene-2, 4-diisocyanate to obtain a first mixed solution, and carrying out a third contact reaction on the first mixture and the 4, 4' -bis (5-hydroxypentanyloxy) biphenyl to obtain a second mixed solution;
(3) carrying out fourth contact reaction on the second mixed solution and a second part of toluene-2, 4-diisocyanate, and carrying out second drying treatment on a product obtained by the fourth contact reaction to obtain a solid material;
(4) in the presence of a solvent III, carrying out first contact mixing on the solid material and epoxy resin to obtain a third mixed solution, and carrying out second contact mixing on the third mixed solution and a curing agent to obtain a first mixed material;
(5) sequentially carrying out defoaming treatment and curing treatment on the first mixed material;
wherein the mass ratio of the first part of toluene-2, 4-diisocyanate to the second part of toluene-2, 4-diisocyanate is 1-6: 1;
the mass ratio of the solid material to the epoxy resin is 1: 5-20.
2. The method of claim 1, wherein the first portion of toluene-2, 4-diisocyanate and the second portion of toluene-2, 4-diisocyanate are used in an amount by mass ratio of 2-4: 1.
3. the method according to claim 1 or 2, wherein the amount mass ratio of the solid material to the epoxy resin is 1: 5-10.
4. The method according to any one of claims 1 to 3, wherein, in step (1), the alcohol is selected from at least one of 3-chloro-1-propanol, 5-chloro-1-pentanol, 6-chloro-1-hexanol, and 8-chloro-1-octanol;
preferably, in the step (1), the mass ratio of the initiator to the 4, 4' -dihydroxybiphenyl to the alcohol is 1:2-5: 6-10.
5. The method of any one of claims 1-4, wherein, in step (1), the first contacting comprises: performing a first reaction under a first condition, and then performing a second reaction under a second condition;
preferably, in step (1), the first condition includes: stirring speed is 40-80rpm, temperature is 40-60 ℃, time is 1-3h, and the second condition comprises: the stirring speed is 40-80rpm, the temperature is 60-80 ℃, and the time is 10-30 h.
6. The method of any one of claims 1-5, wherein in step (2), the thermally conductive filler is alumina and/or boron nitride.
7. The method according to any one of claims 1 to 6, wherein in step (2), the conditions of the second contact reaction comprise at least: stirring at 40-60rpm at 50-80 deg.C for 1-5 hr;
preferably, in step (2), the conditions of the third contact reaction at least include: stirring at 40-60rpm at 60-100 deg.C for 24-30 hr;
preferably, in step (3), the conditions of the fourth contact reaction at least include: the stirring speed is 60-80rpm, the temperature is 60-100 ℃, and the time is 10-20 h.
8. The method according to any one of claims 1 to 7, wherein in step (4), the epoxy resin is an E51 type epoxy resin.
9. The LCPU modified epoxy resin-based heat-conducting composite material prepared by the method of any one of claims 1 to 8.
10. The LCPU modified epoxy resin based thermal conductive composite material of claim 9, for use in integrated circuits or 5G communication.
Technical Field
The invention relates to the technical field of liquid crystal polymer materials, in particular to an LCPU modified epoxy resin-based heat-conducting composite material and a preparation method and application thereof.
Background
Electronic equipment can produce a large amount of heats at the operation in-process, if the heat does not in time give off, will seriously influence the operating efficiency of equipment, also can accelerate electronic product's ageing simultaneously, cause a lot of hidden dangers. Therefore, in order to enable the electronic product to operate efficiently and reliably, the thermally insulating electronic packaging material must have high thermal conductivity.
The electrical insulation property and the good processability of the epoxy resin make the epoxy resin obtain wide attention on the insulation and heat conduction materials, but the thermal conductivity of the epoxy resin is about 0.2W/(m.K), and the epoxy resin has the defects of low thermal conductivity and poor heat conduction performance. Therefore, how to improve the thermal conductivity of the epoxy resin has become a hot point of research.
At present, the heat conductivity of epoxy resin is improved mainly by adding a large amount of heat-conducting fillers, and the filled high-heat-conducting fillers have the advantages of low cost, convenient processing and the like, so that the epoxy resin becomes a key direction of domestic and foreign research.
However, the high content of the high thermal conductive filler is generally added, which causes the density, mechanical properties and forming processing of the composite material to be seriously affected, brings a lot of difficulties to the actual production, and the filler is easy to agglomerate, thereby affecting the actual application effect of the filler.
Therefore, the development of a method which can obtain the epoxy resin-based heat-conducting composite material with high heat conductivity and can avoid filler agglomeration has important significance.
Disclosure of Invention
In view of the defects of the prior art, the invention aims to provide an LCPU modified epoxy resin-based heat-conducting composite material, and a preparation method and application thereof, and aims to solve the technical problem that the existing epoxy resin-based composite material used in the communication field is low in heat conductivity.
In order to achieve the above object, a first aspect of the present invention provides a method for preparing an LCPU modified epoxy resin based thermal conductive composite, comprising the steps of:
(1) in the presence of a solvent I, carrying out a first contact reaction on an initiator, 4 '-dihydroxybiphenyl and alcohol, and carrying out a first drying treatment on a product obtained by the first contact reaction to obtain 4, 4' -bis (5-hydroxypentanyloxy) biphenyl; the molecular formula of the alcohol is Cl- (CH)2)nOH, wherein n is an integer of 3-8;
(2) in the presence of a solvent II, carrying out a second contact reaction on a heat-conducting filler and a first part of toluene-2, 4-diisocyanate to obtain a first mixed solution, and carrying out a third contact reaction on the first mixture and the 4, 4' -bis (5-hydroxypentanyloxy) biphenyl to obtain a second mixed solution;
(3) carrying out fourth contact reaction on the second mixed solution and a second part of toluene-2, 4-diisocyanate, and carrying out second drying treatment on a product obtained by the fourth contact reaction to obtain a solid material;
(4) in the presence of a solvent III, carrying out first contact mixing on the solid material and epoxy resin to obtain a third mixed solution, and carrying out second contact mixing on the third mixed solution and a curing agent to obtain a first mixed material;
(5) sequentially defoaming and curing the first mixed material;
wherein the mass ratio of the first part of toluene-2, 4-diisocyanate to the second part of toluene-2, 4-diisocyanate is 1-6: 1;
the mass ratio of the solid material to the epoxy resin is 1: 5-20.
The second aspect of the invention provides an LCPU modified epoxy resin-based heat-conducting composite material prepared by the method of the first aspect.
The third aspect of the invention provides the application of the LCPU modified epoxy resin-based heat-conducting composite material in the second aspect in integrated circuits or 5G communication.
According to the invention, the filler modified by the liquid crystal polyurethane is mixed with the epoxy resin, so that a continuous heat conduction network can be constructed, and the heat conductivity of the material is improved.
Detailed Description
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.
In the present invention, unless otherwise specified, the room temperature or room temperature is 25. + -. 2 ℃.
As previously mentioned, the first aspect of the present invention provides a method for preparing LCPU modified epoxy resin based heat conductive composite material, which comprises the following steps:
(1) in the presence of a solvent I, carrying out a first contact reaction on an initiator, 4 '-dihydroxybiphenyl and alcohol, and carrying out a first drying treatment on a product obtained by the first contact reaction to obtain 4, 4' -bis (5-hydroxypentanyloxy) biphenyl; the molecular formula of the alcohol is Cl- (CH)2)nOH, wherein n is an integer of 3-8;
(2) in the presence of a solvent II, carrying out a second contact reaction on a heat-conducting filler and a first part of toluene-2, 4-diisocyanate to obtain a first mixed solution, and carrying out a third contact reaction on the first mixture and the 4, 4' -bis (5-hydroxypentanyloxy) biphenyl to obtain a second mixed solution;
(3) carrying out fourth contact reaction on the second mixed solution and a second part of toluene-2, 4-diisocyanate, and carrying out second drying treatment on a product obtained by the fourth contact reaction to obtain a solid material;
(4) in the presence of a solvent III, carrying out first contact mixing on the solid material and epoxy resin to obtain a third mixed solution, and carrying out second contact mixing on the third mixed solution and a curing agent to obtain a first mixed material;
(5) sequentially carrying out defoaming treatment and curing treatment on the first mixed material;
wherein the mass ratio of the first part of toluene-2, 4-diisocyanate to the second part of toluene-2, 4-diisocyanate is 1-6: 1;
the mass ratio of the solid material to the epoxy resin is 1: 5-20.
Preferably, the mass ratio of the first part of toluene-2, 4-diisocyanate to the second part of toluene-2, 4-diisocyanate is 2-4: 1. the inventors have found that with this preferred embodiment, an epoxy resin-based thermally conductive composite material having more excellent thermal conductivity can be obtained.
Preferably, in the step (4), the mass ratio of the solid material to the epoxy resin is 1: 5-10. The inventors found that with this preferred embodiment, the epoxy resin-based thermally conductive composite material obtained has a higher thermal conductivity.
Preferably, in step (1), the alcohol is selected from at least one of 3-chloro-1-propanol, 5-chloro-1-pentanol, 6-chloro-1-hexanol, and 8-chloro-1-octanol.
Preferably, in the step (1), the mass ratio of the initiator to the 4, 4' -dihydroxybiphenyl to the alcohol is 1:2-5: 6-10.
Preferably, in step (1), the operation of the first contact reaction comprises: after the first reaction is carried out under the first condition, the second reaction is carried out under the second condition.
Preferably, in step (1), the first condition includes: stirring speed is 40-80rpm, temperature is 40-60 ℃, time is 1-3h, and the second condition comprises: the stirring speed is 40-80rrpm, the temperature is 60-80 ℃, and the time is 10-30 h.
Preferably, in step (1), the conditions of the first drying treatment include at least: the temperature is 50-60 ℃ and the time is 5-8 h.
Preferably, in step (1), the method further comprises: before the first drying treatment, a product obtained by the first contact reaction is recrystallized for multiple times by using ethanol.
According to a particularly preferred embodiment, in step (1), the solvent I is absolute ethanol.
Preferably, in step (1), the amount of the solvent I used is 100-180mL with respect to 1g of the initiator.
Preferably, in step (1), the initiator is sodium hydroxide.
Preferably, in step (2), the thermally conductive filler is alumina and/or boron nitride.
According to a particularly preferred embodiment, the thermally conductive filler is alumina, and illustratively, the thermally conductive filler is nano alumina having an average particle size of 20 to 40 nm. The inventors have found that with this preferred embodiment, a thermally conductive composite material with better thermal conductivity can be obtained.
Preferably, in the step (2), the amount mass ratio of the heat-conducting filler to the first part of toluene-2, 4-diisocyanate is 1: 3-5.
According to a particularly preferred aspect, in step (2), the solvent II is anhydrous N, N-dimethylformamide.
Preferably, in the step (2), the amount of the solvent II is 10 to 18mL relative to 1g of the heat conductive filler.
Preferably, in step (2), the conditions of the second contact reaction at least include: the stirring speed is 40-60rpm, the temperature is 50-80 ℃, and the time is 1-5 h.
Preferably, in step (2), the conditions of the third contact reaction at least include: the stirring speed is 40-60rpm, the temperature is 60-100 ℃, and the time is 24-30 h.
Preferably, in step (2), the method further comprises: before the third contact reaction, the 4, 4' -bis (5-hydroxypentanyloxy) biphenyl and the N, N-dimethylformamide are mixed and dissolved.
Preferably, in the step (2), the amount of the N, N-dimethylformamide is 6 to 15mL relative to 1g of the 4, 4' -bis (5-hydroxypentanyloxy) biphenyl.
Preferably, in step (3), the conditions of the fourth contact reaction at least include: the stirring speed is 60-80rpm, the temperature is 60-100 ℃, and the time is 10-20 h.
Preferably, in step (3), the method further comprises: before the second drying treatment, the solid-liquid separation is carried out on the product obtained by the fourth contact reaction to obtain a solid product, and the solid product is washed with N, N-dimethylformamide for multiple times.
Preferably, in step (3), the conditions of the second drying treatment include at least: the temperature is 60-80 ℃ and the time is 20-24 h.
According to a particularly preferred embodiment, in step (4), the solvent iii is acetone.
Preferably, in step (4), the first contact mixing is performed under ultrasonic conditions, and the conditions of the first contact mixing at least include: the stirring speed is 500-600rpm, the temperature is 20-40 ℃, and the time is 20-30 min.
Preferably, in step (4), the method further comprises: before the second contact mixing, the third mixed solution is treated for 30-60min under the condition of oil bath at 50-60 ℃.
Preferably, in step (4), the conditions of the second contact mixing include at least: the stirring speed is 500-600rrpm, the temperature is 20-40 ℃, and the time is 20-30 min.
According to a particularly preferred embodiment, in step (4), the epoxy resin is an epoxy resin of type E51.
Preferably, in the step (4), the mass ratio of the epoxy resin to the curing agent is 1: 0.7-0.8.
Preferably, in step (4), the curing agent is selected from methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride.
Preferably, in the step (5), the defoaming treatment is performed under vacuum conditions, and the conditions of the defoaming treatment at least include: the vacuum degree is 0.04-0.06MPa, the temperature is 100-120 ℃, and the time is 20-30 min.
Preferably, in step (5), the conditions of the curing treatment include at least: the temperature is 140 ℃ and 150 ℃, and the time is 8-12 h.
As mentioned above, the second aspect of the present invention provides an LCPU modified epoxy resin based heat conductive composite material prepared by the method of the first aspect.
As mentioned above, the third aspect of the present invention provides the application of the LCPU modified epoxy resin-based thermal conductive composite material of the second aspect in integrated circuits or 5G communication.
The present invention will be described in detail below by way of examples. In the following examples, various raw materials used unless otherwise specified are commercially available.
Epoxy resin: epoxy resin E51 available from Nantong star plastics, Inc.;
in the following examples, unless otherwise specified, the ethanol concentration was 99.7 wt%, the N, N-dimethylformamide concentration was 99 wt%, and the acetone concentration was 99 wt%.
Example 1
The embodiment provides a method for preparing an LCPU modified epoxy resin-based heat-conducting composite material, which comprises the following steps:
(1) in N2Under protection, 0.4g of sodium hydroxide is added into a three-neck flask filled with 50mL of absolute ethyl alcohol, 1.5g of 4,4 '-dihydroxybiphenyl is slowly added into the three-neck flask under the condition of 50rpm of stirring speed, 2.5g of 5-chloro-1-pentanol is dissolved in 50mL of absolute ethyl alcohol, then the obtained solution is slowly added into the flask, the temperature is increased to 50 ℃, the reaction is carried out for 1h, then the temperature is increased to 60 ℃, the condensation reflux is carried out for 24h, after the reaction is finished, the solvent is removed, the reacted product is recrystallized for 3 times by using ethanol, and then the obtained product is placed into a vacuum oven at 60 ℃ for drying for 6h to obtain 4, 4' -bis (5-hydroxypentanyloxy) biphenyl;
(2) in N2Under protection, 3g of dried (180 ℃ C., 24h) nano Al2O3Adding anhydrous N, N-Dimethylformamide (DMF) (the average particle size is 30nm) and 50mL into a three-neck flask, slowly dropwise adding 12g of toluene-2, 4-diisocyanate under the stirring speed of 60rpm, raising the temperature to 60 ℃, reacting for 3h, dissolving 2.5g of the 4, 4' -bis (5-hydroxypentanyloxy) biphenyl into 30mL of DMF, slowly dropwise adding into the flask under the stirring speed of 60rpm, and raising the temperature to 100 ℃, and reacting for 24h to obtain a second mixed solution;
(3) continuously reacting the second mixed solution with 5g of toluene-2, 4-diisocyanate at 100 ℃ for 10h, filtering after the reaction is finished, washing with DMF for 3 times, and finally drying in a vacuum oven at 80 ℃ for 24h to obtain liquid crystal polyurethane modified Al2O3；
(4) 4g of liquid-crystalline polyurethane-modified Al at room temperature2O3Ultrasonically dispersing into 10mL of acetone solvent, adding 20g of epoxy resin, ultrasonically dispersing at 60rpm for 30min, treating in an oil bath at 60 deg.C for 60min, and adding 14g of methyl tetrahydroStirring phthalic anhydride at 60rpm until a homogeneous mixture is formed, namely a first mixed material;
(5) and (2) carrying out vacuum defoaming treatment on the first mixed material in a vacuum oven (the vacuum degree is 0.06MPa) at 100 ℃ for 30min, then casting the first mixed material into a mold, curing the first mixed material at 150 ℃ for 10h, and cooling the first mixed material to room temperature to obtain the LCPU modified epoxy resin-based heat-conducting composite material.
Example 2
This example provides a method for preparing LCPU modified epoxy resin based thermally conductive composite material, the method operating in steps similar to those of example 1, except that:
in step (1), 0.4g of sodium hydroxide was replaced with 0.3g of sodium hydroxide;
in the step (2), 12g of toluene-2, 4-diisocyanate is replaced by 15g of toluene-2, 4-diisocyanate, and the time of the third contact reaction is 30 h;
in step (3), 5g of toluene-2, 4-diisocyanate was replaced with 6g of toluene-2, 4-diisocyanate;
in the step (4), 2g of liquid-crystalline urethane-modified Al2O3Liquid crystalline urethane-modified Al substituted for 4g2O3And 14g of methyltetrahydrophthalic anhydride were replaced by 16g of methyltetrahydrophthalic anhydride.
Example 3
This example provides a method for preparing LCPU modified epoxy resin based thermally conductive composite material, the method operating in steps similar to those of example 1, except that:
in step (1), 1.5g of 4,4 '-dihydroxybiphenyl was replaced with 1g of 4, 4' -dihydroxybiphenyl, and 2.5g of 5-chloro-1-pentanol was replaced with 4g of 3-chloro-1-propanol, and the conditions of the first drying treatment were: the temperature is 80 ℃, and the time is 3 h;
in the step (2), 5g of dried nano Al is used2O3Replace 3g of dried nano Al2O312g of toluene-2, 4-diisocyanate were replaced by 20g of toluene-2, 4-diisocyanate and 2.5g of 4,4 '-bis (5-hydroxypentane) biphenyl were replaced by 3g of 4, 4' -bis (5-hydroxypentane) biphenylOxy) biphenyl, the time of the second contact reaction being 5 h;
in step (4), 14g of methyltetrahydrophthalic anhydride were replaced with 16g of methylhexahydrophthalic anhydride.
Example 4
In this example, an LCPU modified epoxy resin based thermal conductive composite material was prepared similar to example 1, except that: in step (2), 25g of toluene-2, 4-diisocyanate was used in place of 12g of toluene-2, 4-diisocyanate, i.e., the mass ratio of the first portion of toluene-2, 4-diisocyanate to the second portion of toluene-2, 4-diisocyanate was 5: 1.
example 5
This example prepares LCPU modified epoxy resin based thermal conductive composite material similar to example 1, except that in step (2), nanometer Al is replaced by nanometer boron nitride with equal mass2O3。
Example 6
In this example, an LCPU modified epoxy resin based thermal conductive composite material was prepared similar to example 1, except that: in step (4), Al modified with 1g of liquid-crystalline polyurethane2O3Liquid crystalline urethane-modified Al substituted for 4g2O3Namely, the mass ratio of the solid material to the epoxy resin is 1: 20.
Comparative example 1
This comparative example an LCPU modified epoxy resin based thermally conductive composite was followed in a similar way as in example 1, except that in step (2) 12g of toluene-2, 4-diisocyanate was replaced by 5g of toluene-2, 4-diisocyanate, i.e. the amount of the first portion of toluene-2, 4-diisocyanate to the second portion of toluene-2, 4-diisocyanate in the mass ratio of 1: 1.
comparative example 2
This comparative example an LCPU modified epoxy resin based thermally conductive composite was prepared in a similar manner to example 1 except that in step (2), 12g of toluene-2, 4-diisocyanate was replaced with 30g of toluene-2, 4-diisocyanate, i.e., the first portion of toluene-2, 4-diisocyanate and the second portion of toluene-2, 4-diisocyanate were used in a mass ratio of 7: 1.
comparative example 3
This comparative example an LCPU-modified epoxy resin-based thermally conductive composite material was prepared in a similar manner to example 1, except that in step (4), 0.8g of liquid-crystalline polyurethane-modified Al was used2O3Liquid crystalline urethane-modified Al substituted for 4g2O3Namely, the mass ratio of the solid material to the epoxy resin is 1: 25.
Test example
The LCPU modified epoxy resin-based heat-conducting composite materials prepared in the examples and the comparative examples and the E51 epoxy resin are respectively subjected to large thermal coefficient detection, and the specific detection method comprises the following steps: and testing by using a Hot Disk TPS 2500 thermal conductivity coefficient measuring instrument. Specific results are shown in table 1.
TABLE 1
Thermal conductivity, W/(m. K)
Example 1
0.51
Example 2
0.42
Example 3
0.45
Example 4
0.49
Example 5
0.43
Example 6
0.40
Comparative example 1
0.30
Comparative example 2
0.28
Comparative example 3
0.32
E51 type epoxy resin
0.20
As can be seen from Table 1, the epoxy resin-based heat-conducting composite material with high heat conductivity coefficient can be prepared by adopting the method of the invention.
It is to be understood that the invention is not limited to the examples described above, but that modifications and variations may be effected thereto by those of ordinary skill in the art in light of the foregoing description, and that all such modifications and variations are intended to be within the scope of the invention as defined by the appended claims.
- 上一篇：一种医用注射器针头装配设备
- 下一篇：紧凑型摄像模组