New energy heating plate rolling process thermosetting adhesive film formula and preparation method thereof

Abstract

The invention relates to the technical field of adhesive films, in particular to a new energy heating plate rolling process thermosetting adhesive film formula and a preparation method thereof, and the new energy heating plate rolling process thermosetting adhesive film formula comprises the following components: core-shell acrylic resin, loaded modified multi-walled carbon nanotubes, a curing agent system, auxiliary components, polyurethane resin, a flame retardant and ethyl acetate; a core layer of the core-shell type acrylic resin is formed by polymerizing methyl methacrylate and butyl acrylate; the curing agent system comprises isocyanate, epoxy resin and microencapsulated silicone rubber; through cooperation of multiple components, the performance of the thermosetting adhesive film is greatly improved. The core-shell type acrylic resin adopts a soft-core and hard-shell structure, and methyl methacrylate and butyl acrylate in a core layer endow the adhesive film with excellent flexibility and impact resistance, so that mechanical stress in the rolling process can be effectively buffered; and a hydroxyl cross-linked network formed by acrylonitrile and hydroxyethyl methylacrylate of a shell layer obviously enhances the heat-resistant stability.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesive films, and in particular to a formula of a thermosetting adhesive film produced by a rolling process of a new energy heating plate and a preparation method thereof. Background Art

[0002] Due to the increasing environmental pressure, most industries have begun to continuously develop the new energy industry in order to reduce emissions and alleviate environmental pressure. Against the background of the rapid development of the new energy industry, the new energy heating plate is the core component of the energy conversion and thermal management system. Its technological iteration has strategic significance for performance breakthroughs in new energy vehicles, solar thermal power generation and energy storage equipment.

[0003] Taking electric vehicles as an example, the battery modules will produce drastic temperature fluctuations during the charging and discharging process (temperature range -30°C to 80°C), and the heating plate needs to maintain the battery cells in the optimal operating range of 20-40°C through precise temperature control. This places higher demands on the weather resistance and thermal conductivity stability of the thermosetting adhesive film. Especially when used in the photovoltaic field, the heating plate needs to adapt to extreme temperature differences of -40°C to 150°C, and the performance requirements of each part of the heating plate are high. Traditional adhesive films are prone to interfacial delamination during long-term thermal cycles, resulting in an increase in thermal resistance of more than 30%, which directly affects the photoelectric conversion efficiency and greatly limits its use.

[0004] Traditional thermosetting films face significant technical bottlenecks in material system design: First, the glass transition temperature (Tg) of mainstream acrylic films is often below 100°C. When the operating temperature of the heating plate exceeds 80°C, the intensified movement of molecular segments causes the elastic modulus of the film to drop by 80%, triggering the expansion of interfacial microcracks. Tests have shown that more than 30% of the thermal conductivity channels of such films fail after 2,000 hours at 120°C. Second, the dispersion of conventional fillers (such as aluminum oxide and boron nitride) in the resin matrix is less than 60%, making it difficult for the thermal conductivity to exceed 0.8W / m·K, making it impossible to meet the heat dissipation requirements of high-power devices (such as fast-charging battery modules) exceeding 2W / m·K.

[0005] More importantly, the products prepared by traditional technology cannot form a three-dimensional thermal network, and the heat flux density exceeds 50W / cm 2 Local hot spots will appear, accelerating material aging. These defects seriously restrict the reliability and cycle life of new energy devices in high-temperature and high-power scenarios.

[0006] Based on this, the present invention provides a new energy heating plate roller pressing process thermosetting adhesive film formula and preparation method thereof to solve the above problems. Summary of the Invention

[0007] In response to the problems existing in the prior art, the present invention provides a formula for a thermosetting adhesive film using a roller pressing process for a new energy heating plate and a preparation method thereof.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A thermosetting adhesive film formulation for a new energy heating plate rolling process, comprising the following components by weight: 55-65 parts of core-shell acrylic resin, 1.8-2.2 parts of loaded modified multi-walled carbon nanotubes, 6-9 parts of curing agent system, 8-12 parts of auxiliary components, 12-15 parts of polyurethane resin, 4-6 parts of flame retardant, and 40-45 parts of ethyl acetate;

[0010] The flame retardant is magnesium hydroxide;

[0011] The core layer of the core-shell acrylic resin is polymerized from methyl methacrylate and butyl acrylate, and the shell layer is polymerized from acrylonitrile and 2-hydroxyethyl methacrylate;

[0012] The curing agent system includes isocyanates, epoxy resins and microencapsulated silicone rubber.

[0013] As a further technical solution, the core layer of the core-shell acrylic resin is formed by semi-continuous emulsion polymerization of methyl methacrylate and butyl acrylate to form a core structure with a particle size of 55-75 nm, so that the tensile strength of the adhesive film is ≥15 MPa and the elongation at break is ≥30%, endowing the resin with elasticity and impact resistance to adapt to the mechanical stress during the rolling process.

[0014] As a further technical solution, the auxiliary components include plasticizers, fillers, coupling agents and antioxidants.

[0015] As a further technical solution, the plasticizer in the auxiliary components is dioctyl phthalate (DOP), accounting for 24-26 wt% of the auxiliary component content, so that the melt viscosity of the adhesive film is ≤500 Pa·s during the 80°C rolling pre-pressing stage, improving the processing fluidity. The KH-560 coupling agent accounting for 3.3-3.7 wt% of the auxiliary component content makes the dispersion uniformity of the filler in the resin ≥95%; the antioxidant is hindered phenol AO-1010, accounting for 1.4-1.6 wt% of the auxiliary component content; the filler is nano-silica (SiO2) with a particle size of 15-25 nm, and the balance. After the adhesive film is aged in an air atmosphere at 120°C for 500 h, the tensile strength retention rate is ≥80%.

[0016] As a further technical solution, the loaded and modified multi-walled carbon nanotubes are subjected to surface functionalization treatment. First, a mixed solution of 65% concentrated nitric acid and 30% hydrogen peroxide with a volume ratio of (2.8 - 3.2):1 is used to oxidize the multi-walled carbon nanotubes, and then silane coupling agents KH-550 and APTES are grafted step by step to form -NH2 and -Si-O- groups, reducing the contact angle between the multi-walled carbon nanotubes and the resin to 20 - 25°, and the thermal conductivity coefficient of the adhesive film reaches 1.8 - 2.2 W / m·K, constructing an efficient three-dimensional heat conduction channel.

[0017] As a further technical solution, the loaded and modified multi-walled carbon nanotubes are uniformly embedded in the resin network by ultrasonic-assisted dispersion method. The ultrasonic frequency is 35 - 45 kHz, the dispersion time is 25 - 35 min, the addition amount is 1.8 - 2.2 wt%, and the aggregate size of the multi-walled carbon nanotubes in the resin after dispersion is ≤50 nm, ensuring the continuity of the heat conduction channel.

[0018] As a further technical solution, the isocyanate in the curing agent system is hexamethylene diisocyanate, accounting for 42.5 - 43.5 wt% of the curing agent system content, and cross-linking reaction occurs at 125 - 145 °C, with a reaction activation energy of 60 - 70 kJ / mol; the epoxy resin is DDS (4,4'-diaminodiphenyl sulfone), accounting for 13.2 - 13.8 wt% of the curing agent system content, and acts as a latent curing agent to react with the hydroxyl groups in the resin to form an interpenetrating network structure; the particle size of the microencapsulated silicone rubber is 6 - 9 μm, and the balance. The repair agent is released when the thermal stress ≥5 MPa, and the recovery rate of the interfacial bonding strength of the adhesive film after repair is ≥85%.

[0019] A preparation method of a thermosetting adhesive film for a new energy heating plate rolling process, comprising the following steps:

[0020] Synthesis of core-shell acrylic resin: Methyl methacrylate, butyl acrylate and initiator APS accounting for 0.4 - 0.6% of the total mass of monomers are polymerized at 78 - 82 °C for 1.5 - 2.5 h to prepare a seed emulsion, forming a core layer; then acrylonitrile and 2-hydroxyethyl methacrylate monomers are added dropwise at a rate of 0.5 - 1.0 g / min and emulsifier SDS accounting for 0.8 - 1.2% of the aqueous phase mass, and the reaction is carried out under insulation for 3.5 - 4.5 h to form a shell layer; finally, spray drying is carried out by controlling the inlet air temperature at 115 - 125 °C to obtain resin powder;

[0021] Loading and dispersion of MWCNTs: Mix multi-walled carbon nanotubes with a mixed solution of concentrated nitric acid and hydrogen peroxide, and reflux at 58 - 62 °C for 3.5 - 4.5 h for oxidative modification. Centrifuge and wash until the pH value is 6.5 - 7.5; Dissolve 0.4 - 0.6% of KH-550 and 0.2 - 0.4% of APTES based on the mass of multi-walled carbon nanotubes in ethanol, and ultrasonically mix with the oxidatively modified multi-walled carbon nanotubes at a frequency of 40 kHz for 28 - 32 min, and react at 78 - 82 °C for 1.5 - 2.5 h for coupling grafting; Add the modified multi-walled carbon nanotubes into the resin emulsion, and stir at a high speed of 1100 - 1300 rpm and ultrasonically treat for 30 - 40 min to form a homogeneous system;

[0022] Adhesive film forming process: Add resin powder, curing agent, filler, additive, polyurethane resin, flame retardant, and ethyl acetate into a high-speed mixer in sequence, and mix at 80 - 90 °C for 12 - 18 min to obtain an adhesive film solution;

[0023] Coat the adhesive film solution on the upper surface of the substrate layer, and then attach a release layer on the upper surface of the substrate layer.

[0024] As a further technical solution, the substrate layer is a PE micro-mucosal film;

[0025] The release layer is a PE micro-mucosal film.

[0026] As a further technical solution, the thickness of the thermosetting adhesive film is 150 um ± 10 um, wherein the thickness of the substrate layer is 70 ± 5 um, the thickness of the cured layer of the adhesive film solution is 30 ± 2 um, and the thickness of the release layer is 50 ± 5 um.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] Through the synergistic cooperation of multiple components, the performance of the thermosetting adhesive film is greatly improved. With the "soft core and hard shell" structure of the core-shell type acrylic resin, methyl methacrylate and butyl acrylate in the core layer endow the adhesive film with excellent flexibility and impact resistance, which can effectively buffer the mechanical stress during the rolling process; The hydroxyl crosslinking network formed by acrylonitrile and 2-hydroxyethyl methacrylate in the shell layer significantly enhances the heat resistance stability.

[0029] The loaded and modified multi-walled carbon nanotubes are double-modified by "oxidation-coupling" to construct a multi-functional group structure of carboxyl, amino, and siloxy groups on the surface, significantly reducing the contact angle between the carbon nanotubes and the resin, and achieving nano-scale uniform dispersion. The ultrasonic-assisted dispersion process promotes the formation of a three-dimensional heat conduction network by the loaded and modified multi-walled carbon nanotubes, and the thermal conductivity coefficient is significantly improved, which is significantly higher than that of the traditional adhesive film. At the same time, the active groups on the surface of the carbon nanotubes chemically bond with the resin hydroxyl groups, enhancing the interfacial bonding force.

[0030] The curing agent system adopts a multi-component synergistic mechanism of isocyanate and epoxy resin: hexamethylene diisocyanate rapidly crosslinks with the resin hydroxyl groups to form a rigid polyurethane network; the DDS latent curing agent slowly initiates the etherification reaction between the epoxy resin and the resin hydroxyl groups to construct an interpenetrating network structure, significantly improving the tensile strength and elongation at break of the adhesive film. The microencapsulated silicone rubber ruptures and releases the repair agent when the thermal stress ≥ 5 MPa, and the repair efficiency for microcracks reaches more than 85%, effectively extending the service life of the adhesive film.

[0031] Through chemical bonding, physical filling and synergistic reactions of each component, a comprehensive breakthrough has been achieved in the heat resistance, thermal conductivity, mechanical properties and self-repair ability of the adhesive film, providing a reliable guarantee for the efficient and stable operation of the new energy heating plate. Specific embodiments

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] Embodiment 1, adhesive film formulation, by weight: 55 parts of core-shell acrylic resin, 2 parts of loaded modified multi-walled carbon nanotubes, 7 parts of curing agent system, 10 parts of auxiliary components, 12 parts of polyurethane resin, 4 parts of flame retardant, 40 parts of ethyl acetate;

[0034] The flame retardant is magnesium hydroxide;

[0035] Among them, the core layer of the core-shell acrylic resin is formed by semi-continuous emulsion polymerization of 45 parts of methyl methacrylate and 35 parts of butyl acrylate to form a core structure with a particle size of 65 nm; the shell layer is polymerized from 22 parts of acrylonitrile and 18 parts of 2-hydroxyethyl methacrylate.

[0036] In the curing agent system, hexamethylene diisocyanate accounts for 43% of the content of the curing agent system, undergoes a crosslinking reaction at 130 °C, and the reaction activation energy is 65 kJ / mol; DDS (4,4'-diaminodiphenyl sulfone) accounts for 13.5% of the content of the curing agent system; the particle size of the microencapsulated silicone rubber is 7 μm, and the balance.

[0037] Among the auxiliary components, dioctyl phthalate (DOP) as a plasticizer accounts for 25% of the content of the auxiliary components, KH-560 coupling agent accounts for 3.5% of the content of the auxiliary components, antioxidant hindered phenol AO-1010 accounts for 1.5% of the content of the auxiliary components, the particle size of nano-silica (SiO2) is 20 nm, and the balance. The thickness of the thermosetting adhesive film is 150 um ± 10 um. Among them, the thickness of the substrate layer is 70 ± 5 um, the thickness of the cured layer of the adhesive film liquid is 30 ± 2 um, and the thickness of the release layer is 50 ± 5 um.

[0038] Preparation method:

[0039] Synthesis of core-shell acrylic resin: Methyl methacrylate, butyl acrylate and initiator APS accounting for 0.5% of the total mass of monomers were added to the reaction kettle, and polymerized at 80 °C for 2 h to prepare a seed emulsion, forming a core layer.

[0040] Acrylonitrile, 2-hydroxyethyl methacrylate monomers and emulsifier SDS accounting for 1% of the mass of the aqueous phase were added dropwise at a rate of 0.7 g / min, and the reaction was carried out at a constant temperature for 4 h to form a shell layer.

[0041] Controlled the inlet air temperature at 120 °C for spray drying to obtain resin powder.

[0042] Loading and dispersion of MWCNTs: Multi-walled carbon nanotubes were mixed with a mixed solution of 65% concentrated nitric acid and 30% hydrogen peroxide with a volume ratio of 3:1 and refluxed at 60 °C for 4 h for oxidation modification, and centrifuged and washed until the pH value was 7.

[0043] KH-550 accounting for 0.5% of the mass of multi-walled carbon nanotubes and 0.3% of APTES were dissolved in ethanol, and ultrasonically mixed with the oxidized multi-walled carbon nanotubes at a frequency of 40 kHz for 30 min, and reacted at 80 °C for 2 h for coupling grafting.

[0044] The modified multi-walled carbon nanotubes were added to the resin emulsion, and stirred at a high speed of 1200 rpm and ultrasonically treated for 35 min to form a homogeneous system.

[0045] Adhesive film forming process: Resin powder, curing agent, filler and additives, polyurethane resin, flame retardant, ethyl acetate were added to a high-speed mixer in sequence, and mixed at 80 °C for 12 min to obtain an adhesive film liquid;

[0046] The adhesive film liquid was coated on the upper surface of the substrate layer, and then the release layer was attached to the upper surface of the substrate layer; the substrate layer was a PE micro-mucosal film;

[0047] The release layer was a PE micro-mucosal film; the adhesive film was tested at a temperature of 85 °C, a humidity of 85%, and a condition of 1000H, and the peel strength could still meet the use requirements.

[0048] Example 2, Adhesive Film Formula, by weight: 58 parts of core-shell acrylic resin, 1.9 parts of loaded modified multi-walled carbon nanotubes, 8 parts of curing agent system, 10.1 parts of auxiliary components, 13 parts of polyurethane resin, 5 parts of flame retardant, 42 parts of ethyl acetate;

[0049] The flame retardant is magnesium hydroxide;

[0050] The core layer of the core-shell acrylic resin is formed by polymerizing 48 parts of methyl methacrylate and 32 parts of butyl acrylate to form a core structure with a particle size of 60 nm; the shell layer is polymerized from 23 parts of acrylonitrile and 17 parts of 2-hydroxyethyl methacrylate.

[0051] In the curing agent system, hexamethylene diisocyanate accounts for 42.8% of the curing agent system content, undergoes a cross-linking reaction at 128 °C, and the reaction activation energy is 63 kJ / mol; DDS accounts for 13.3% of the curing agent system content; the microencapsulated silicone rubber has a particle size of 8 μm, and the balance.

[0052] In the auxiliary components, dioctyl phthalate (DOP) as a plasticizer accounts for 24.8% of the auxiliary component content, KH-560 coupling agent accounts for 3.4% of the auxiliary component content, antioxidant hindered phenol AO-1010 accounts for 1.45% of the auxiliary component content, and nano-silica (SiO2) has a particle size of 18 nm, and the balance. The thickness of the thermosetting adhesive film is 150 μm ± 10 μm, among which, the thickness of the substrate layer is 70 ± 5 μm, the thickness of the cured layer of the adhesive film liquid is 30 ± 2 μm, and the thickness of the release layer is 50 ± 5 μm.

[0053] Preparation Method:

[0054] Synthesis of core-shell acrylic resin: Polymerize methyl methacrylate, butyl acrylate and initiator APS accounting for 0.45% of the total monomer mass at 79 °C for 2.2 h to prepare a seed emulsion to form the core layer.

[0055] Dropwise add acrylonitrile, 2-hydroxyethyl methacrylate monomers and emulsifier SDS accounting for 0.9% of the aqueous phase mass at a rate of 0.6 g / min, and keep the temperature for reaction for 3.8 h to form the shell layer.

[0056] Control the inlet air temperature at 118 °C for spray drying to obtain resin powder.

[0057] Loading and dispersion of MWCNTs: Mix multi-walled carbon nanotubes with a mixed solution of concentrated nitric acid and hydrogen peroxide with a volume ratio of 2.9:1 and reflux at 59 °C for 3.8 h for oxidation modification, and centrifuge and wash until the pH value is 6.8.

[0058] Dissolve 0.48% of KH-550 and 0.28% of APTES, which account for the mass of multi-walled carbon nanotubes, in ethanol, and ultrasonically mix them with the oxidized and modified multi-walled carbon nanotubes at a frequency of 40 kHz for 29 min, and react at 79 °C for 2.2 h for coupling grafting.

[0059] Add the modified multi-walled carbon nanotubes into the resin emulsion, and stir at a high speed of 1150 rpm and ultrasonically treat for 32 min to form a homogeneous system.

[0060] Adhesive film forming process: sequentially add resin powder, curing agent, filler and additives, polyurethane resin, flame retardant, and ethyl acetate into a high-speed mixer, and mix at 86 °C for 15 min to obtain an adhesive film solution;

[0061] Coat the adhesive film solution on the upper surface of the substrate layer, and then attach a release layer on the upper surface of the substrate layer; the substrate layer is a PE micro-mucosal film;

[0062] The release layer is a PE micro-mucosal film; this adhesive film is tested under the conditions of a temperature of 85 °C, a humidity of 85%, and 1000H, and the peel strength can still meet the use requirements.

[0063] Example 3, adhesive film formulation, by weight: 62 parts of core-shell acrylic resin, 2.1 parts of loaded and modified multi-walled carbon nanotubes, 6.9 parts of curing agent system, 9.9 parts of auxiliary components, 15 parts of polyurethane resin, 6 parts of flame retardant, 45 parts of ethyl acetate;

[0064] The flame retardant is magnesium hydroxide;

[0065] The core layer of the core-shell acrylic resin is formed by polymerizing 42 parts of methyl methacrylate and 38 parts of butyl acrylate to form a core structure with a particle size of 70 nm; the shell layer is polymerized from 21 parts of acrylonitrile and 19 parts of 2-hydroxyethyl methacrylate.

[0066] In the curing agent system, hexamethylene diisocyanate accounts for 43.2% of the content of the curing agent system, undergoes a cross-linking reaction at 132 °C, and the reaction activation energy is 67 kJ / mol; DDS accounts for 13.7% of the content of the curing agent system; the particle size of the microencapsulated silicone rubber is 6 μm, and the balance.

[0067] In the auxiliary components, the plasticizer dioctyl phthalate (DOP) accounts for 25.2% of the content of the auxiliary components, the KH-560 coupling agent accounts for 3.6% of the content of the auxiliary components, the antioxidant hindered phenol AO-1010 accounts for 1.55% of the content of the auxiliary components, the particle size of nano-silica (SiO2) is 22 nm, and the balance. The thickness of the thermosetting adhesive film is 150 μm ± 10 μm, among which, the thickness of the substrate layer is 70 ± 5 μm, the thickness of the cured layer of the adhesive film solution is 30 ± 2 μm, and the thickness of the release layer is 50 ± 5 μm.

[0068] Preparation method:

[0069] Synthesis of core-shell acrylic resin: Methyl methacrylate, butyl acrylate and initiator APS accounting for 0.55% of the total mass of monomers were polymerized at 81 °C for 2.3 h to prepare a seed emulsion, forming the core layer.

[0070] Acrylonitrile, 2-hydroxyethyl methacrylate monomers and emulsifier SDS accounting for 1.1% of the mass of the aqueous phase were added dropwise at a rate of 0.8 g / min, and the reaction was carried out at a constant temperature for 4.2 h to form the shell layer.

[0071] Spray drying was carried out by controlling the inlet air temperature at 122 °C to obtain resin powder.

[0072] Loading and dispersion of MWCNTs: Multi-walled carbon nanotubes were mixed with a mixed solution of concentrated nitric acid and hydrogen peroxide with a volume ratio of 3.1:1 and refluxed at 61 °C for 4.2 h for oxidation modification, and centrifuged and washed until the pH value reached 7.2.

[0073] KH-550 accounting for 0.52% of the mass of multi-walled carbon nanotubes and APTES accounting for 0.32% were dissolved in ethanol, and ultrasonically mixed with the oxidized multi-walled carbon nanotubes at a frequency of 40 kHz for 31 min, and reacted at 81 °C for 2.3 h for coupling grafting.

[0074] The modified multi-walled carbon nanotubes were added to the resin emulsion, and stirred at a high speed of 1250 rpm and ultrasonically treated for 38 min to form a homogeneous system.

[0075] Adhesive film forming process: Resin powder, curing agent, filler and additives, polyurethane resin, flame retardant, ethyl acetate were added to a high-speed mixer in sequence, and mixed at 90 °C for 18 min to obtain an adhesive film liquid;

[0076] The adhesive film liquid was coated on the upper surface of the substrate layer, and then a release layer was attached to the upper surface of the substrate layer; the substrate layer was a PE micro-mucosa film;

[0077] The release layer was a PE micro-mucosa film; the adhesive film was tested at a temperature of 85 °C, a humidity of 85%, and a condition of 1000H, and the peel strength could still meet the use requirements.

[0078] Comparative Example 1, adhesive film formula, by weight: 55 parts of core-shell acrylic resin, 0 part of loaded and modified multi-walled carbon nanotubes, 7 parts of curing agent system, 10 parts of auxiliary components;

[0079] The composition of the core layer and shell layer of the core-shell acrylic resin, and the proportions of various substances in the curing agent system and auxiliary components were the same as those in Example 1. The thickness of the thermosetting adhesive film was 150 μm ± 10 μm. Among them, the thickness of the substrate layer was 70 ± 5 μm, the thickness of the cured layer of the adhesive film liquid was 30 ± 2 μm, and the thickness of the release layer was 50 ± 5 μm. Preparation method:

[0080] The preparation method is the same as that of Example 1, except that the supported modified multi-walled carbon nanotubes are not added, and the remaining steps and parameters remain the same.

[0081] Comparative Example 2, adhesive film formulation, by weight: 55 parts of core-shell acrylic resin, 2 parts of supported modified multi-walled carbon nanotubes, 0 part of curing agent system, 10 parts of auxiliary components;

[0082] The compositions of the core layer and the shell layer of the core-shell acrylic resin and the proportions of the substances in the auxiliary components are the same as those in Example 1. The thickness of the thermosetting adhesive film is 150 um ± 10 um, wherein the thickness of the substrate layer is 70 ± 5 um, the thickness of the cured layer of the adhesive film liquid is 30 ± 2 um, and the thickness of the release layer is 50 ± 5 um.

[0083] Preparation method:

[0084] The preparation method is the same as that of Example 1, except that the curing agent system is not added, and the remaining steps and parameters remain the same.

[0085] Performance test:

[0086] Thermal conductivity test:

[0087] The laser flash method was used to measure the thermal conductivity of the adhesive films prepared in Examples 1-3 and Comparative Examples 1-2, and the test temperature was 25 °C;

[0088] Table 1:

[0089]

[0090]

[0091] As can be seen from Table 1, the adhesive film obtained by the present invention has a higher thermal conductivity coefficient.

[0092] Heat resistance test:

[0093] The adhesive film samples were placed in a high-temperature environment of 150 °C for 100 h, and the mass change and mechanical properties of the adhesive film were measured before and after the test:

[0094] Table 2:

[0095]

[0096] As can be seen from Table 2, the adhesive film prepared by the present invention has high heat resistance.

[0097] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification.

Claims

1. A formula for a thermosetting adhesive film in a roll pressing process of a new energy heating plate, characterized in that, It comprises the following components by weight parts: 55 - 65 parts of core - shell acrylic resin, 1.8 - 2.2 parts of loaded modified multi - walled carbon nanotubes, 6 - 9 parts of curing agent system, 8 - 12 parts of auxiliary components, 12 - 15 parts of polyurethane resin, 4 - 6 parts of flame retardant, and 40 - 45 parts of ethyl acetate; The flame retardant is magnesium hydroxide; The core layer of the core - shell acrylic resin is polymerized from methyl methacrylate and butyl acrylate, and the shell layer is polymerized from acrylonitrile and 2 - hydroxyethyl methacrylate; The curing agent system includes isocyanates, epoxy resins and microencapsulated silicone rubber.

2. The formulation of the thermosetting adhesive film for the roll pressing process of the new energy heating plate according to claim 1, wherein, The core layer of the core - shell acrylic resin is formed by semi - continuous emulsion polymerization of methyl methacrylate and butyl acrylate to form a core structure with a particle size of 55 - 75 nm.

3. The hot solid adhesive film formulation for the roll pressing process of the new energy heating plate according to claim 1, characterized in that, The auxiliary components include plasticizers, fillers, coupling agents and antioxidants.

4. The thermosetting adhesive film formulation for the roll pressing process of the new energy heating plate according to claim 3, wherein, In the auxiliary components, the plasticizer is dioctyl phthalate (DOP), accounting for 24 - 26 wt% of the content of the auxiliary components, and the coupling agent KH - 560 accounting for 3.3 - 3.7 wt% of the content of the auxiliary components makes the dispersion uniformity of the filler in the resin ≥95%; the antioxidant is hindered phenol AO - 1010, accounting for 1.4 - 1.6 wt% of the content of the auxiliary components; the filler is nano - silica (SiO₂) with a particle size of 15 - 25 nm, and the balance.

5. The hot solid adhesive film formulation for the roll pressing process of the new energy heating plate according to claim 1, characterized in that, The loaded modified multi - walled carbon nanotubes are surface - functionalized. First, a mixed solution of 65% concentrated nitric acid and 30% hydrogen peroxide with a volume ratio of (2.8 - 3.2):1 is used to oxidize the multi - walled carbon nanotubes, and then they are grafted step - by - step with silane coupling agents KH - 550 and APTES to form - NH₂ and - Si - O - groups, reducing the contact angle between the multi - walled carbon nanotubes and the resin to 20 - 25°, and the thermal conductivity coefficient of the adhesive film reaches 1.8 - 2.2 W / m·K, constructing an efficient three - dimensional heat conduction channel.

6. The formulation of the thermosetting adhesive film for the roll pressing process of the new energy heating plate according to claim 1 or 5, characterized in that The loaded modified multi - walled carbon nanotubes are uniformly embedded in the resin network by ultrasonic - assisted dispersion method. The ultrasonic frequency is 35 - 45 kHz, the dispersion time is 25 - 35 min, and the addition amount is 1.8 - 2.2 wt%.

7. The formulation of the thermosetting adhesive film for the roll pressing process of the new energy heating plate according to claim 1, characterized in that, In the curing agent system, the isocyanate is hexamethylene diisocyanate, accounting for 42.5 - 43.5 wt% of the content of the curing agent system, and it undergoes a cross - linking reaction at 125 - 145 °C with a reaction activation energy of 60 - 70 kJ / mol; the epoxy resin is DDS (4,4'-diaminodiphenyl sulfone), accounting for 13.2 - 13.8 wt% of the content of the curing agent system, and it reacts with the hydroxyl groups in the resin as a latent curing agent to form an interpenetrating network structure; the particle size of the microencapsulated silicone rubber is 6 - 9 μm, and the balance.

8. A method for preparing a thermosetting adhesive film for a new energy heating plate rolling process according to any one of claims 1-7, characterized in that, It includes the following steps: Synthesis of core-shell acrylic resin: Methyl methacrylate, butyl acrylate and initiator APS accounting for 0.4 - 0.6% of the total mass of monomers were polymerized at 78 - 82 °C for 1.5 - 2.5 h to prepare a seed emulsion, forming the core layer; then acrylonitrile, 2-hydroxyethyl methacrylate monomers and emulsifier SDS accounting for 0.8 - 1.2% of the mass of the aqueous phase were added dropwise at a rate of 0.5 - 1.0 g / min, and the reaction was carried out under heat preservation for 3.5 - 4.5 h to form the shell layer; finally, spray drying was carried out by controlling the inlet air temperature at 115 - 125 °C to obtain resin powder; Loading and dispersion of MWCNTs: Multi-walled carbon nanotubes were mixed with a mixed solution of concentrated nitric acid and hydrogen peroxide and refluxed at 58 - 62 °C for 3.5 - 4.5 h for oxidation modification, and centrifuged and washed until the pH value was 6.5 - 7.5; KH-550 accounting for 0.4 - 0.6% of the mass of multi-walled carbon nanotubes and APTES accounting for 0.2 - 0.4% were dissolved in ethanol, and ultrasonically mixed with the oxidized multi-walled carbon nanotubes at a frequency of 40 kHz for 28 - 32 min, and reacted at 78 - 82 °C for 1.5 - 2.5 h for coupling grafting; the modified multi-walled carbon nanotubes were added to the resin emulsion, and high-speed stirring and ultrasonic treatment were carried out at a speed of 1100 - 1300 rpm for 30 - 40 min to form a homogeneous system; Glue film forming process: Resin powder, curing agent, filler, auxiliary agent, polyurethane resin, flame retardant, ethyl acetate were added to a high-speed mixer in sequence, and mixed at 80 - 90 °C for 12 - 18 min to obtain a glue film solution; The glue film solution was coated on the upper surface of the substrate layer, and then a release layer was attached to the upper surface of the substrate layer.

9. The method according to claim 8, wherein The substrate layer is a PE micro-mucosa film; the release layer is a PE micro-mucosa film.

10. The method according to claim 8, characterized in that, The thickness of the thermosetting glue film is 150 um ± 10 um, among which, the thickness of the substrate layer is 70 ± 5 um, the thickness of the cured layer of the glue film solution is 30 ± 2 um, and the thickness of the release layer is 50 ± 5 um.

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