A thermally conductive tape film and preparation method thereof

Abstract

The present application relates to the technical field of packaging materials, and specifically discloses a thermally conductive adhesive tape film and a preparation method thereof. A thermally conductive adhesive tape film comprises the following raw materials in parts by weight: 100-120 parts of polypropylene powder, 0.8-1 parts of stabilizer, 1.5-2 parts of plasticizer, 2-5 parts of graphene, and 1-3 parts of carbon nanotubes; its preparation method is: all the raw materials are mixed, melt-extruded and granulated, and then formed and rolled to obtain a thermally conductive adhesive tape film. The thermal conductivity coefficient of the adhesive tape film of the present application can reach 0.7456-0.8912 W / (m×K), and the thermal conductivity is excellent. The thermal conductivity of the tape made with the adhesive tape film of the present application is also improved. In a higher temperature usage scenario, the heat on the adhered object can be quickly transferred out through the tape film, greatly reducing the aging effect of high temperature on the tape, especially on the adhesive, and ensuring that the viscosity of the tape is maintained.

Description

Technical Field

[0001] The present application relates to the technical field of packaging materials, and more specifically, to a thermally conductive adhesive tape film and a preparation method thereof. Background Art

[0002] Adhesive tape is a commonly used packaging material in daily production and life. Adhesive tape generally consists of a tape film and an adhesive, and the adhesive is coated on the tape film.

[0003] Tape film is generally a resin film. After the resin polymer sheet is preheated in the temperature range above its glass transition temperature and below its melting point, a stretching machine is used to apply a certain external force in the longitudinal and transverse directions to orient the molecular chains along the stretching direction and arrange them in order. The molecular structure is then fixed by heat setting and cooling to produce a stretched film.

[0004] With respect to the above-mentioned related technologies, the applicant has found that the temperature in the use scenarios of some adhesive tapes is relatively high. Under the influence of temperature, the viscosity of the adhesive tape will be affected, thereby affecting its packaging effect. Summary of the Invention

[0005] In order to improve the thermal conductivity of a tape film, the present application provides a thermally conductive tape film and a preparation method thereof.

[0006] In a first aspect, the present application provides a thermally conductive adhesive tape film, which adopts the following technical solution:

[0007] A thermally conductive adhesive tape film comprises the following raw materials in parts by weight: 100-120 parts of polypropylene powder, 0.8-1 part of a stabilizer, 1.5-2 parts of a plasticizer, 2-5 parts of graphene, and 1-3 parts of carbon nanotubes.

[0008] By adopting the above technical solution, polypropylene resin is used as the film-forming resin of the tape film, and then graphene and carbon nanotube fillers are added. Graphene is a new carbon material in which carbon atoms are tightly arranged into a single-layer two-dimensional honeycomb lattice structure. It is a two-dimensional sp2 bond hybridized single-layer carbon atom crystal. This low-dimensional structure significantly reduces the boundary scattering of phonons at the grain boundaries and relies on special phonon modes for heat transfer. Phonons are energy quanta of the lattice vibration normal mode. They transfer heat in a ballistic-diffusion manner and exhibit excellent thermal conductivity. Carbon nanotubes themselves have good thermal conductivity, and carbon nanotubes have a very large aspect ratio, so their heat exchange performance along the length direction is very high.

[0009] Graphene and carbon nanotubes are used as fillers in adhesive tape films. Graphene's thermal conductivity mechanism makes its heat transfer purely two-dimensional, while the aspect ratio of carbon nanotubes results in high heat exchange performance along their length. Graphene and carbon nanotubes are dispersed in a polypropylene resin matrix, where the carbon nanotubes connect the graphene. The combination of graphene and carbon nanotubes forms a three-dimensional heat conduction channel, significantly improving the thermal conductivity of the adhesive tape. Adhesive tapes made with this highly conductive film also exhibit improved thermal conductivity. In higher temperature applications, heat from the adhered object can be quickly transferred through the tape film, significantly reducing the aging effects of high temperatures on the tape, particularly the adhesive, and ensuring that the tape maintains its viscosity.

[0010] Preferably, the graphene is surface modified.

[0011] By adopting the above technical solution, surface treatment can improve the dispersion performance of graphene in polypropylene resin, make graphene evenly dispersed in polypropylene resin, reduce graphene aggregation, and make graphene easier to contact with carbon nanotubes to form a three-dimensional heat conduction channel, thereby improving the thermal conductivity of the tape film.

[0012] Preferably, the surface modification treatment method of the graphene is:

[0013] Graphene is dispersed in a dispersion to obtain a graphene dispersion, an initiator is added to the graphene dispersion, the mixture is mixed, and then N,N-dimethylbisacrylamide is added and mixed; acrylic acid is then added under protective gas protection, the mixture is stirred and reacted at 60-70° C. for 60-70 minutes, the mixture is cooled to 25-27° C., and the mixture is allowed to stand for 4-5 hours. After the reaction is completed, a solid is obtained by filtering, the solid is washed, and the solid is dried to a constant weight to obtain modified graphene.

[0014] By adopting the above technical solution, acrylic acid is grafted on the surface of graphene, which can, on the one hand, improve the dispersion performance of graphene and reduce the aggregation of graphene in the polypropylene system; on the other hand, grafting acrylic acid on the surface of graphene can convert the inorganic-organic bond between graphene and polypropylene resin into an organic-organic bond, thereby improving the bonding force between graphene and polyacrylic acid, thereby ensuring the mechanical properties of the tape film material.

[0015] Preferably, the weight ratio of graphene to acrylic acid is 1:(20-25).

[0016] By adopting the above technical solution, the ratio of graphene to acrylic acid is limited. Within the range defined in this application, the grafting rate of acrylic acid on graphene can be controlled at a relatively high level; if the acrylic acid content is too low, the modification effect will be poor; if the acrylic acid content is too high, the acrylic acid monomers will polymerize to form homopolymers, resulting in an increase in the viscosity of the reaction system, hindering the diffusion of acrylic acid monomer molecules into the substrate graphene, thereby reducing the grafting rate.

[0017] Preferably, the carbon nanotubes are surface modified.

[0018] By adopting the above technical solution, surface treatment can improve the dispersion performance of carbon nanotubes in polypropylene resin, so that the carbon nanotubes are evenly dispersed in the polypropylene resin, thereby increasing the probability of carbon nanotubes and graphene combining, making it easier for graphene to contact with carbon nanotubes to form a three-dimensional heat conduction channel, thereby improving the thermal conductivity of the tape film.

[0019] Preferably, the surface modification treatment method of the carbon nanotubes is:

[0020] The carbon nanotubes are dissolved in water and then ultrasonically crushed and dispersed to obtain a carbon nanotube dispersion; dopamine hydrochloride is added to the carbon nanotube dispersion and stirred to react to obtain a reaction solution; a buffer solution is added to the reaction solution to continue the reaction; after the reaction is completed, a solid is obtained by filtering; the solid is washed and dried to a constant weight to obtain modified carbon nanotubes.

[0021] By adopting the above technical solution, carbon nanotubes are non-covalently modified with dopamine hydrochloride. Dopamine is deposited and polymerized on the surface of the carbon nanotubes to form polydopamine. Polydopamine contains benzene rings and has π electrons on the surface. It can interact with the π electrons on the benzene rings on the surface of the carbon nanotubes through π-π electron coupling. Polydopamine also contains -OH, which can act as a hydrogen bond donor and form hydrogen bonds with the graphite sheets on the carbon nanotubes. It is adsorbed on the outer wall of the carbon nanotubes and improves the dispersibility of the carbon nanotubes. On the other hand, the polydopamine loaded on the surface of the carbon nanotubes can convert the inorganic-organic bond between the carbon nanotubes and the polypropylene resin into an organic-organic bond, thereby improving the bonding strength between the carbon nanotubes and the polyacrylic acid, thereby ensuring the mechanical properties of the tape film material.

[0022] Preferably, the weight ratio of the carbon nanotubes to dopamine hydrochloride is 1:(80-100).

[0023] By adopting the above technical solution, the ratio of carbon nanotubes to dopamine hydrochloride is limited, thereby limiting the loading amount of polydopamine on the carbon nanotubes, so that the dispersibility of the carbon nanotubes reaches a relatively good level.

[0024] In a second aspect, the present application provides a method for preparing a thermally conductive tape film, which adopts the following technical solution:

[0025] A method for preparing a thermally conductive tape film comprises the following steps:

[0026] All raw materials are mixed, melt-extruded and granulated, and then formed and rolled to obtain a thermal conductive tape film.

[0027] By adopting the above technical solution, the preparation method of the present application is simple and easy to operate, has no special requirements for production equipment, and is suitable for industrial development.

[0028] In summary, this application has the following beneficial effects:

[0029] 1. Since the present application adopts polypropylene resin as the film-forming resin of the tape film, and then adds graphene and carbon nanotube fillers, the low-dimensional structure of graphene significantly reduces the boundary scattering of phonons at the grain boundaries, and relies on special phonon modes for heat transfer. Phonons are lattice vibration normal mode energy quanta, which transfer heat in a ballistic-diffusion manner and exhibit excellent thermal conductivity. Carbon nanotubes themselves have good thermal conductivity, and carbon nanotubes have a very large aspect ratio, so their heat exchange performance along the length direction is very high. Using graphene and Carbon nanotubes are compounded as fillers for the tape film. Due to the thermal conductivity mechanism of graphene, the heat transfer of graphene is purely two-dimensional, and the aspect ratio of carbon nanotubes makes the carbon nanotubes have high heat exchange performance along the length direction. Graphene and carbon nanotubes are dispersed in a matrix of polypropylene resin. Carbon nanotubes connect the graphene. Graphene and carbon nanotubes cooperate to form a three-dimensional heat conduction channel, which greatly improves the thermal conductivity of the tape film. The thermal conductivity coefficient of the obtained tape film can reach 0.7456-0.8912W / (m×K).

[0030] 2. In this application, it is preferred to graft acrylic acid on the surface of graphene to improve the dispersion performance of graphene in polypropylene resin, so that graphene is evenly dispersed in polypropylene resin, reducing the aggregation of graphene, thereby making it easier for graphene to contact with carbon nanotubes to form a three-dimensional heat conduction channel, thereby improving the thermal conductivity of the tape film. The thermal conductivity coefficient of the obtained tape film can reach 0.7964-0.8912W / (m×K).

[0031] 3. In this application, dopamine hydrochloride is preferably used to non-covalently modify the carbon nanotubes to improve the dispersion performance of the carbon nanotubes in the polypropylene resin, so that the carbon nanotubes are uniformly dispersed in the polypropylene resin, thereby increasing the probability of the carbon nanotubes and graphene combining, making it easier for the graphene to contact with the carbon nanotubes to form a three-dimensional heat conduction channel, thereby improving the thermal conductivity of the tape film. The thermal conductivity coefficient of the obtained tape film can reach 0.8212-0.8912 W / (m×K). DETAILED DESCRIPTION

[0032] The present application is further described in detail below with reference to the embodiments.

[0033] Preparation examples of raw materials and intermediates

[0034] raw material

[0035] Polypropylene powder, brand H-XD-045;

[0036] Stabilizer, which is light stabilizer 944;

[0037] Plasticizer, which is a phthalate plasticizer;

[0038] Graphene, brand N006-P;

[0039] Carbon nanotubes are multi-walled carbon nanotubes with an outer diameter of 30-50nm, an inner diameter of 8-15nm, and a length of

[0040] <10 μm, purity >98%;

[0041] DMF, Runfeng;

[0042] N, N-dimethylbisacrylamide, Runfeng C0075-1ton;

[0043] Acrylic acid, industrial grade;

[0044] Dopamine hydrochloride, Sigma-Aldrich, H8502-10G;

[0045] The buffer solution is Tris buffer solution, 10 mmol / L, pH=8.5.

[0046] Preparation Example

[0047] Preparation Example I-1

[0048] A modified graphene, the preparation method of which is:

[0049] 0.8 kg of graphene was dispersed in 800 kg of LDMF dispersion to obtain a graphene dispersion, 1.2 kg of ammonium persulfate initiator was added to the graphene dispersion and mixed, and then 1 kg of N, N-dimethylbisacrylamide was added and mixed; then 16 kg of acrylic acid was added under nitrogen protection gas, and the mixture was stirred and reacted at 60 ° C for 60 minutes, then cooled to 25 ° C and allowed to stand for 4 hours. After the reaction was completed, a solid was obtained by filtration, and the solid was washed and dried to constant weight to obtain modified graphene.

[0050] Preparation Example I-2

[0051] Different from Preparation Example I-1, the amount of acrylic acid used in Preparation Example I-2 is 20 kg.

[0052] Preparation Example I-3

[0053] Different from Preparation Example I-1, the amount of acrylic acid used in Preparation Example I-3 is 10 kg.

[0054] Preparation Example I-4

[0055] Different from Preparation Example I-1, the amount of acrylic acid used in Preparation Example I-4 is 25 kg.

[0056] Preparation Example II-1

[0057] A modified carbon nanotube, the preparation method of which is:

[0058] 0.01 kg of carbon nanotubes were dissolved in 30 L of water, and then ultrasonically crushed and dispersed using an ultrasonic crusher at 150 W power in an ice bath for 15 minutes to obtain a carbon nanotube dispersion; 0.8 kg of dopamine hydrochloride was added to the carbon nanotube dispersion, and the mixture was stirred and reacted for 15 minutes to obtain a reaction solution, 1 L of buffer solution was added to the reaction solution, and the reaction was continued for 12 hours. After the reaction was completed, the solid was filtered to obtain the solid, and the solid was washed and dried to constant weight to obtain modified carbon nanotubes.

[0059] Preparation Example II-2

[0060] Different from Preparation Example II-1, the amount of dopamine hydrochloride used in Preparation Example II-2 is 1 kg.

[0061] Preparation Example II-3

[0062] Different from Preparation Example II-1, the amount of dopamine hydrochloride used in Preparation Example II-3 is 0.6 kg.

[0063] Preparation Example II-4

[0064] Different from Preparation Example II-1, the amount of dopamine hydrochloride used in Preparation Example II-4 is 1.2 kg.

[0065] Example

[0066] Examples 1-3

[0067] A thermally conductive adhesive tape film, and a preparation method thereof is as follows:

[0068] According to the raw material ratio in Table 1, polypropylene powder, stabilizer, plasticizer, graphene, and carbon nanotubes were mixed, and then melt-extruded and granulated at 200° C., and then formed and rolled to obtain a thermal conductive tape film.

[0069] Table 1 Example 1-3 Raw material ratio table (kg)

[0070] Example 1 Example 2 Example 3 Polypropylene powder 100 110 120 stabilizer 1.0 0.9 0.8 plasticizers 1.5 1.8 2.0 graphene 2 3 5 carbon nanotubes 3 2 1

[0071] Example 4

[0072] Different from Example 2, in Example 4, the graphene is replaced by an equal amount of modified graphene from Preparation Example I-1.

[0073] Example 5

[0074] Different from Example 4, the modified graphene in Example 5 comes from Preparation Example I-2.

[0075] Example 6

[0076] Different from Example 4, the modified graphene in Example 6 comes from Preparation Example I-3.

[0077] Example 7

[0078] Different from Example 4, the modified graphene in Example 7 comes from Preparation Example I-4.

[0079] Example 8

[0080] Different from Example 2, in Example 8, the carbon nanotubes were replaced by an equal amount of modified carbon nanotubes from Preparation Example II-1.

[0081] Example 9

[0082] Different from Example 5, in Example 9, the carbon nanotubes were replaced by an equal amount of modified carbon nanotubes from Preparation Example II-1.

[0083] Example 10

[0084] Different from Example 9, the modified carbon nanotubes in Example 10 are respectively from Preparation Example II-2.

[0085] Example 11

[0086] Different from Example 9, the modified carbon nanotubes in Example 11 are respectively from Preparation Example II-3.

[0087] Example 12

[0088] Different from Example 9, the modified carbon nanotubes in Example 12 are respectively from Preparation Example II-4.

[0089] Comparative Example

[0090] Comparative Example 1

[0091] The difference from Example 1 is that in Comparative Example 1, an equal amount of graphene is used to replace the carbon nanotubes.

[0092] Comparative Example 2

[0093] Different from Example 1, in Comparative Example 2, an equal amount of carbon nanotubes was used to replace graphene.

[0094] Comparative Example 3

[0095] Different from Example 1, Comparative Example 3 does not contain graphene and carbon nanotubes.

[0096] Performance testing

[0097] Detection method / test method

[0098] The following performance tests were performed on the adhesive tape films prepared in the examples and comparative examples. The test results are shown in Table 2:

[0099] Thermal conductivity test: The thermal conductivity of the tape film is tested according to the method in ASTM D 5470-06, Standard Test Method for Thermal Transfer Properties of Thermally Conductive Electrical Insulating Materials.

[0100] Mechanical properties: The tensile strength of the tape film is tested according to the method in "Determination of tensile properties of plastics Part 3: Test conditions for thin plastics and sheets" GB / T1040.3-2006.

[0101] Table 2 Performance test results

[0102]

[0103]

[0104] Combining Examples 1-12 and Comparative Examples 1-3, and Table 2, it can be seen that the thermal conductivity coefficients of the tape films in Examples 1-12 are all higher than those in Comparative Examples 1-3, which indicates that the tape films prepared in the present application have better thermal conductivity and are suitable for use in high temperature environments.

[0105] Combining Example 1 and Comparative Examples 1-3, and combining Table 2, it can be seen that the filler in Comparative Example 1 contains only graphene, the filler in Comparative Example 2 contains only carbon nanotubes, and Comparative Example 3 does not contain filler. The thermal conductivity coefficients of the tape films in Comparative Examples 1-3 are all lower than those in Example 1, among which the thermal conductivity coefficient of the tape film in Comparative Example 3 is lower than that of Comparative Examples 1-2, that is, the thermal conductivity of the tape film of Example 1 is better than that of Comparative Examples 1-3, and the thermal conductivity of the tape film of Comparative Examples 1-2 is better than that of Comparative Example 3. This shows that the addition of graphene and carbon nanotubes can improve the thermal conductivity of the tape film. High thermal conductivity of the tape film; this may be because graphene and carbon nanotubes are both relatively good thermally conductive materials, and adding them to the tape film can improve the tape film's thermal conductivity. Moreover, the combination of graphene and carbon nanotubes is more effective than using either graphene or carbon nanotubes alone. This may be because when graphene and carbon nanotubes are used together, the graphene and carbon nanotubes are dispersed in a polypropylene resin matrix, and the carbon nanotubes connect the graphene. The graphene and carbon nanotubes work together to form a three-dimensional thermal conductive channel, greatly improving the thermal conductivity of the tape film. The thermal conductivity of tape made with tape film with good thermal conductivity is also improved. In high-temperature usage scenarios, heat from the adhered object can be quickly transferred through the tape film, greatly reducing the aging effect of high temperature on the tape, especially the adhesive, and ensuring that the tape's viscosity is maintained.

[0106] Combining Examples 1-3 and Table 2, it can be seen that the thermal conductivity of the adhesive tape films in Examples 1-3 is good, among which the raw material ratio in Example 2 is better.

[0107] Combining Example 2 with Examples 4-7 and Table 2, it can be seen that the thermal conductivity of the tape film in Example 4-7 is higher than that in Example 2, that is, the thermal conductivity of the tape film in Example 4-7 is better than that in Example 2, which shows that surface modification of graphene can improve the thermal conductivity of the tape film; this may be because surface modification of graphene with acrylic acid can improve the dispersion performance of graphene in polypropylene resin, so that graphene is evenly dispersed in polypropylene resin, reducing graphene aggregation, thereby making it easier for graphene to contact with carbon nanotubes to form a three-dimensional heat conduction channel, thereby improving the thermal conductivity of the tape film.

[0108] In combination with Examples 4-7 and Table 2, it can be seen that the thermal conductivity of the tape film in Examples 4-5 is higher than that in Examples 6-7, which indicates that within the ratio range of graphene to acrylic acid specified in the present application, the modified graphene obtained has the best effect on improving the thermal conductivity of the tape film; this may be because within the range specified in the present application, the grafting rate of acrylic acid on graphene can be controlled at a relatively high level; if the acrylic acid content is too low, the modification effect will be poor; if the acrylic acid content is too high, the acrylic acid monomers will polymerize to form homopolymers, resulting in an increase in the viscosity of the reaction system, hindering the diffusion of acrylic acid monomer molecules to the substrate graphene, thereby reducing the grafting rate.

[0109] Combining Example 2 with Example 8 and Table 2, it can be seen that the thermal conductivity of the tape film in Example 8 is higher than that in Example 2. This shows that surface modification of carbon nanotubes can improve the thermal conductivity of the tape film. This may be because the surface treatment can improve the dispersion of carbon nanotubes in the polypropylene resin, making the carbon nanotubes evenly dispersed in the polypropylene resin, thereby increasing the probability of carbon nanotubes combining with graphene, making it easier for graphene to contact with the carbon nanotubes to form a three-dimensional thermal conductive channel, thereby improving the thermal conductivity of the tape film.

[0110] Combining Examples 4-12 and Table 2, it can be seen that the thermal conductivity of the tape films in Examples 9-12 is better than that in Examples 4-8, which shows that surface modification of both graphene and carbon nanotubes can effectively improve the thermal conductivity of the tape films.

[0111] In combination with Examples 9-12 and Table 2, it can be seen that the thermal conductivity of the tape film in Examples 4-5 is higher than that in Examples 6-7, which indicates that the ratio of dopamine hydrochloride to carbon nanotubes will affect the thermal conductivity of the tape film. Within the ratio range of dopamine hydrochloride to carbon nanotubes specified in this application, the modified carbon nanotubes obtained have the best effect on improving the thermal conductivity of the tape film.

[0112] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A thermally conductive tape film, characterized in that: The invention comprises the following raw materials in parts by weight: 100-120 parts of polypropylene powder, 0.8-1 part of stabilizer, 1.5-2 parts of plasticizer, 2-5 parts of graphene, and 1-3 parts of carbon nanotubes; The graphene is surface-modified; the surface modification method of the graphene is: Dispersing graphene in a dispersion to obtain a graphene dispersion, adding an initiator to the graphene dispersion, mixing, and then adding N,N-dimethylbisacrylamide and mixing; then adding acrylic acid under protective gas protection, stirring and reacting at 60-70° C. for 60-70 minutes, then cooling to 25-27° C., standing for 4-5 hours, and after the reaction is completed, filtering to obtain a solid, washing the solid, and drying to a constant weight to obtain modified graphene; The carbon nanotubes are surface modified; the surface modification method of the carbon nanotubes is: The carbon nanotubes are dissolved in water and then ultrasonically crushed and dispersed to obtain a carbon nanotube dispersion; dopamine hydrochloride is added to the carbon nanotube dispersion and stirred to react to obtain a reaction solution; a buffer solution is added to the reaction solution to continue the reaction; after the reaction is completed, a solid is obtained by filtering; the solid is washed and dried to a constant weight to obtain modified carbon nanotubes.

2. The thermally conductive tape film according to claim 1, characterized in that: The weight ratio of the graphene to the acrylic acid is 1:(20-25).

3. The thermally conductive tape film according to claim 1, wherein: The weight ratio of the carbon nanotubes to dopamine hydrochloride is 1:(80-100).

4. A method for preparing the thermally conductive tape film according to any one of claims 1 to 3, characterized in that: The following steps are involved: All raw materials are mixed, melt-extruded and granulated, and then formed and rolled to obtain a thermal conductive tape film.

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