Hot melt adhesive, preparation method thereof, anisotropic conductive adhesive film and intelligent card

Abstract

The invention discloses a hot melt adhesive and a preparation method thereof, an anisotropic conductive adhesive film and an intelligent card. The hot melt adhesive comprises the following components in percentage by mass: 40%-70% of thermoplastic copolyamide, 10%-30% of thermoplastic copolyester and 20%-40% of a conductive material, wherein the melting point of the thermoplastic copolyamide is 100 DEG C to 140 DEG C, and the thermoplastic copolyester comprises one or two of crystalline thermoplastic copolyester with the melting point of 100 DEG C to 140 DEG C and amorphous thermoplastic copolyester with the glass transition temperature of 5 DEG C to 30 DEG C. According to the hot melt adhesive provided by the invention, the thermoplastic copolyester is used for providing high-strength adhesion, the thermoplastic copolyamide is used for adjusting the flexibility to serve as a resin matrix, a specific conductive material is used in a matched mode to form a stable conductive network, and the hot melt adhesive with good adhesion thrust and ethanol resistance is obtained.

Description

Technical Field

[0001] This application relates to the field of encapsulation materials, and in particular to a hot melt adhesive and its preparation method, anisotropic conductive film, and smart card. Background Technology

[0002] Smart cards have embedded microprocessors or integrated circuit chips, and compared with magnetic cards, they have the advantages of large information storage capacity and high storage security, and their application prospects are extremely broad.

[0003] In the smart card manufacturing process, the rapid and effective bonding of the chip module (mainly epoxy resin fiber composite material) to the card substrate (mainly PVC material) is a crucial step determining the product's production efficiency and quality. Traditional methods primarily use ordinary copolyamide (PA) hot melt adhesive films as anisotropic conductive films to bond and encapsulate the chip module and card substrate. However, in smart card encapsulation applications, the bonding force between the chip and the card substrate after heat sealing is weak, barely reaching the standard limit of around 80N; furthermore, the heat sealing time for the soldering head is long, resulting in low production efficiency. In addition, ordinary adhesive tape is an insulating material and cannot be used in products such as dual-interface bank cards; and the copolyamide hot melt adhesives used for card substrate encapsulation have poor ethanol resistance. Summary of the Invention

[0004] Therefore, it is necessary to provide a hot melt adhesive with good adhesion and ethanol resistance, a method for its preparation, an anisotropic conductive film, and a smart card.

[0005] This application provides a hot melt adhesive, which, by mass percentage, comprises 40% to 70% thermoplastic copolyamide, 10% to 30% thermoplastic copolyester, and 20% to 40% conductive material.

[0006] The thermoplastic copolyamide has a melting point of 100℃~140℃, and the thermoplastic copolyester includes one or two of crystalline thermoplastic copolyesters with a melting point of 100℃~140℃ and amorphous thermoplastic copolyesters with a glass transition temperature of 5℃~30℃.

[0007] In one embodiment, the thermoplastic copolyamide includes one or more of Arkema HX2592, Nylon 66, and Arkema H2519.

[0008] In one embodiment, the thermoplastic copolyester satisfies one or both of the following conditions:

[0009] (1) The crystalline thermoplastic copolyester includes one or more of EMS ES500, EMS ES702, Festi PES E20 and Festi PES 3730.

[0010] (2) The non-crystalline thermoplastic copolyester includes one or more of Toyobo 670, Toyobo 673 and Toyobo 630.

[0011] In one embodiment, the conductive material includes one or more of metallic copper, metallic tin, metallic silver, metallic copper, and metallic aluminum.

[0012] In one embodiment, the particle size of the conductive material is 25 μm to 45 μm.

[0013] This application also provides a method for preparing a hot melt adhesive, comprising the following steps:

[0014] The raw materials are provided for the composition of the hot melt adhesive as described above;

[0015] The raw materials are mixed and extruded to prepare the hot melt adhesive.

[0016] In one embodiment, the extrusion temperature is 160°C to 180°C.

[0017] Furthermore, this application provides an anisotropic conductive adhesive film, comprising the hot melt adhesive as described above.

[0018] In one embodiment, the thickness is 40 μm to 60 μm.

[0019] Furthermore, this application also provides a smart card, including a substrate and a chip, wherein the substrate and the chip are encapsulated by the hot melt adhesive as described above or the anisotropic conductive film as described above.

[0020] The hot melt adhesive provided in this application utilizes thermoplastic copolyester to provide high-strength bonding and thermoplastic copolyamide to adjust flexibility as a resin matrix, and uses specific conductive materials to form a stable conductive network, thereby obtaining a hot melt adhesive that has both good adhesive thrust and ethanol resistance. Detailed Implementation

[0021] To facilitate understanding of this application, it may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0023] As used herein, the term "and / or" encompasses any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" includes three parallel options: A, B, and "a combination of A and B".

[0024] In this document, unless otherwise stated, "one or more" means any one of the listed items or any combination of the listed items. Similarly, "one or more" and other instances of "one or more" are to be understood in the same way unless otherwise stated.

[0025] In this document, terms such as "further," "even further," "especially," "for example," "like," "example," and "exemplary" are used for descriptive purposes to indicate a connection in the coverage of different technical solutions presented earlier and later. However, they should not be construed as limitations on the preceding technical solution or on the scope of protection of this document. Unless otherwise specified, in this document, A (e.g., B) indicates that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0026] In this document, "optionally," "optionally," and "optional" mean that something is optional, that is, it is selected from either "present" or "absent." If multiple "options" appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "option" is independent. In this application, descriptions such as "optionally contains" and "optionally includes" indicate "contains or does not contain." "Optional component X" indicates whether component X exists or does not exist, or whether component X is contained or not.

[0027] In this document, the terms "first aspect," "second aspect," "third aspect," and "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," and "fourth" serve only as a non-exhaustive enumeration and should be understood as not constituting a closed limitation on quantity.

[0028] In this article, the technical features described in an open-ended manner include both closed technical solutions composed of the listed features and open technical solutions that include the listed features.

[0029] In this document, when referring to numerical intervals (i.e., numerical ranges), unless otherwise specified, the distribution of selectable values ​​within a numerical interval is considered continuous, and includes the two endpoints (i.e., the minimum and maximum values) of the numerical interval, as well as every value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed herein should be understood to include any and all subranges included therein. The "numerical value" in this numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include percentage intervals, ratio intervals, proportion intervals, and other numerical interval types.

[0030] In this document, the term "room temperature" or "normal temperature" generally refers to 4°C to 35°C, for example, 20°C ± 5°C. In some embodiments of this document, "room temperature" or "normal temperature" refers to 10°C to 30°C. In some embodiments of this document, "room temperature" or "normal temperature" refers to 20°C to 30°C.

[0031] In this document, for methods involving multiple steps, unless otherwise explicitly stated herein, there is no strict order constraint on the execution of these steps; they may be executed in any order other than those described. Moreover, any step may include multiple sub-steps or multiple stages, which are not necessarily completed at the same time, but may be executed at different times, and their execution order is not necessarily sequential, but may be executed in turn, alternately, or simultaneously with other steps or parts of the sub-steps or stages of other steps.

[0032] This application provides a hot melt adhesive, which, by mass percentage, comprises 40% to 70% thermoplastic copolyamide, 10% to 30% thermoplastic copolyester, and 20% to 40% conductive material.

[0033] The melting point of thermoplastic copolyamide is 100℃~140℃. Thermoplastic copolyester includes one or two of crystalline thermoplastic copolyesters with a melting point of 100℃~140℃ and amorphous thermoplastic copolyesters with a glass transition temperature of 5℃~30℃.

[0034] The hot melt adhesive provided in this application utilizes thermoplastic copolyester to provide high-strength bonding and thermoplastic copolyamide to adjust flexibility as a resin matrix, and uses specific conductive materials to form a stable conductive network, thereby obtaining a hot melt adhesive that has both good adhesive thrust and ethanol resistance.

[0035] Specifically, the melting points of the thermoplastic copolyamides can be, but are not limited to, 100℃, 101℃, 102℃, 103℃, 104℃, 105℃, 106℃, 107℃, 108℃, 109℃, 110℃, 111℃, 112℃, 113℃, 114℃, 115℃, 116℃, 117℃, 118℃, 119℃, 120℃, 121℃, 122℃, 123℃, 124℃, 125℃, 126℃, 127℃, 128℃, 129℃, 130℃, 131℃, 132℃, 133℃, 134℃, 135℃, 136℃, 137℃, 138℃, 139℃, or 140℃.

[0036] The melting points of crystalline thermoplastic copolyesters can be, but are not limited to, 100℃, 101℃, 102℃, 103℃, 104℃, 105℃, 106℃, 107℃, 108℃, 109℃, 110℃, 111℃, 112℃, 113℃, 114℃, 115℃, 116℃, 117℃, 118℃, 119℃, 120℃, 121℃, 122℃, 123℃, 124℃, 125℃, 126℃, 127℃, 128℃, 129℃, 130℃, 131℃, 132℃, 133℃, 134℃, 135℃, 136℃, 137℃, 138℃, 139℃, or 140℃.

[0037] The glass transition temperature of amorphous thermoplastic copolyesters can be, but is not limited to, 5℃, 6℃, 7℃, 8℃, 9℃, 10℃, 11℃, 12℃, 13℃, 14℃, 15℃, 16℃, 17℃, 18℃, 19℃, 20℃, 21℃, 22℃, 23℃, 24℃, 25℃, 26℃, 27℃, 28℃, 29℃, or 30℃.

[0038] Understandably, the mass percentage of thermoplastic copolyamide in the hot melt adhesive may be, but is not limited to, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, or 70%.

[0039] Furthermore, the mass percentage of thermoplastic copolyester in the hot melt adhesive may be, but is not limited to, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, or 30%.

[0040] Furthermore, the percentage of the mass of conductive material in the hot melt adhesive may be, but is not limited to, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, or 40%.

[0041] In one specific example, the thermoplastic copolyamide includes one or more of Arkema HX2592, Arkema M1276, and Arkema H2519.

[0042] In one specific example, the crystalline thermoplastic copolyester includes one or more of EMS ES500, EMS ES702, Festi PES E20, and Festi PES 3730.

[0043] In one specific example, the amorphous thermoplastic copolyester includes one or more of Toyobo 670, Toyobo 673, and Toyobo 630.

[0044] In one specific example, the conductive material includes one or more of metallic copper, metallic tin, metallic silver, metallic copper, and metallic aluminum.

[0045] Furthermore, the conductive material may be, but is not limited to, one or more of copper, tin alloy, silver-clad copper, silver-clad aluminum, and silver.

[0046] In one specific example, the particle size of the conductive material is 25μm~45μm.

[0047] Specifically, the particle size of the conductive material can be, but is not limited to, 25μm, 30μm, 35μm, 40μm or 45μm.

[0048] This application also provides a method for preparing a hot melt adhesive, comprising the following steps:

[0049] The raw materials are provided for the composition of the hot melt adhesive as described above;

[0050] Mix raw materials, extrude, and prepare hot melt adhesive.

[0051] In one specific example, the extrusion temperature is 160℃~180℃.

[0052] Specifically, the extrusion temperature can be, but is not limited to, 160℃, 161℃, 162℃, 163℃, 164℃, 165℃, 166℃, 167℃, 168℃, 169℃, 170℃, 171℃, 172℃, 173℃, 174℃, 175℃, 176℃, 177℃, 178℃, 179℃, or 180℃. Following the extrusion step, embossing, cooling, traction, and winding processes are also included. The hot melt adhesive formed can be, but is not limited to, a film structure, and can be obtained in the desired shape as needed.

[0053] Understandably, the mixed raw materials are prepared into granules. Furthermore, the granules can be formed by, but is not limited to, extruding the mixed raw materials and then cutting them into granules. Specifically, the extrusion temperature in this step is 160°C to 180°C.

[0054] Furthermore, this application provides an anisotropic conductive adhesive film, comprising the hot melt adhesive as described above.

[0055] In a specific example, the thickness of the anisotropic conductive film is 40μm~60μm.

[0056] Specifically, the thickness of the anisotropic conductive film can be, but is not limited to, 40μm, 41μm, 42μm, 43μm, 44μm, 45μm, 46μm, 47μm, 48μm, 49μm, 50μm, 51μm, 52μm, 53μm, 54μm, 55μm, 56μm, 57μm, 58μm, 59μm or 60μm.

[0057] Furthermore, this application also provides a smart card, including a substrate and a chip, wherein the substrate and the chip are encapsulated by hot melt adhesive as described above or an anisotropic conductive film as described above.

[0058] Understandably, the anisotropic conductive film (ACF) containing the above-mentioned hot melt adhesive is unidirectionally conductive in the Z-axis direction and has good conductivity, which can effectively achieve good encapsulation while also enabling the chip to operate effectively.

[0059] The present application will be further described in detail below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present application. For experimental methods in the following embodiments where specific conditions are not specified, please refer to the guidelines given in this application, or follow experimental manuals or conventional conditions in the art, or follow the conditions recommended by the manufacturer, or refer to experimental methods known in the art.

[0060] In the specific embodiments described below, the measurement parameters of the raw material components may have slight deviations within the weighing accuracy range unless otherwise specified. For temperature and time parameters, acceptable deviations due to instrument testing accuracy or operational precision are permissible. "Ambient temperature" refers to 25°C; "atmospheric pressure" refers to 100 kPa or 101 kPa.

[0061] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0062] The alloy material Sn used in the following examples 98.5 Ag1Cu 0.5 Purchased from Hebei Yuehan Metal Materials Sales Co., Ltd. Thermoplastic copolyamides include M 1276 and HX 2592 purchased from Arkema. Thermoplastic copolyesters include ES500 purchased from EMS, PES E20 purchased from Fessett, and 670 purchased from Toyobo.

[0063] Example 1

[0064] This embodiment provides a hot melt adhesive film, the preparation method of which includes the following steps:

[0065] (1) Weigh 7 kg of thermoplastic copolyamide (Arkema M 1276), 1 kg of thermoplastic copolyester (EMS ES500), and 2 kg of copper powder (25-45 μm) for later use. Mix the materials using a twin-screw extruder and cut the materials into granules. The extrusion temperature is 160-180℃.

[0066] (2) The mixture obtained in step (1) is added to a single screw extruder, extruded at 160-180℃ and formed into a film. After embossing, cooling, traction and winding processes, a hot melt adhesive film is prepared.

[0067] Example 2

[0068] This embodiment provides a hot melt adhesive film, which differs from Example 1 only in its raw material composition. Its preparation method includes the following steps:

[0069] (1) Weigh 4 kg of thermoplastic copolyamide (Arkema M 1276), 2 kg of thermoplastic copolyester (EMS ES500), and 4 kg of copper powder (25-45 μm) for later use. Mix the materials using a twin-screw extruder and cut the materials into granules. The extrusion temperature is 160-180℃.

[0070] (2) The mixture obtained in step (1) is added to a single screw extruder, extruded at 160-180℃ and formed into a film. After embossing, cooling, traction and winding processes, a hot melt adhesive film is prepared.

[0071] Example 3

[0072] This embodiment provides a hot melt adhesive film, which differs from Example 1 only in its raw material composition. Its preparation method includes the following steps:

[0073] (1) Weigh 5 kg of thermoplastic copolyamide (Arkema HX 2592), 2 kg of thermoplastic copolyester (Fessetti PES E20), and 3 kg of silver-coated copper powder (25-45 μm) from Guangdong Dexiang New Materials for later use. Mix the materials using a twin-screw extruder and cut the materials into granules. The extrusion temperature is 160-180℃.

[0074] (2) The mixture obtained in step (1) is added to a single screw extruder, extruded at 160-180℃ and formed into a film. After embossing, cooling, traction and winding processes, a hot melt adhesive film is prepared.

[0075] Example 4

[0076] This embodiment provides a hot melt adhesive film, which differs from Example 1 only in its raw material composition. Its preparation method includes the following steps:

[0077] (1) Weigh 6 kg of thermoplastic copolyamide (Arkema M 1276), 1 kg of amorphous thermoplastic copolyester (Toyobo 670), and 3 kg of tin alloy powder Sn. 98.5 Ag1Cu 0.5 (25-45μm) is reserved. The material is mixed using a twin-screw extruder and cut into granules. The extrusion temperature is 160-180℃.

[0078] (2) The mixture obtained in step (1) is added to a single screw extruder, extruded at 160-180℃ and formed into a film. After embossing, cooling, traction and winding processes, a hot melt adhesive film is prepared.

[0079] Example 5

[0080] This embodiment provides a hot melt adhesive film, which differs from Example 1 only in its raw material composition. Its preparation method includes the following steps:

[0081] (1) Weigh 4 kg of thermoplastic copolyamide (Arkema M 1276), 3 kg of thermoplastic copolyester (EMS ES500), and 3 kg of copper powder (25-45 μm) for later use. Mix the materials using a twin-screw extruder and cut the materials into granules. The extrusion temperature is 160-180℃.

[0082] (2) The mixture obtained in step (1) is added to a single screw extruder, extruded at 160-180℃ and formed into a film. After embossing, cooling, traction and winding processes, a hot melt adhesive film is prepared.

[0083] Comparative Example 1

[0084] This comparative example provides a hot melt adhesive film that differs from Example 1 only in its raw material composition. Its preparation method includes the following steps:

[0085] (1) Weigh 7 kg of thermoplastic copolyamide (Arkema M 1276), 1 kg of thermoplastic copolyester (EMS ES500), and 2 kg of copper powder (10-20 μm) for later use. Mix the materials using a twin-screw extruder and cut the materials into granules. The extrusion temperature is 160-180℃.

[0086] (2) The mixture obtained in step (1) is added to a single screw extruder, extruded at 160-180℃ and formed into a film. After embossing, cooling, traction and winding processes, a hot melt adhesive film is prepared.

[0087] Comparative Example 2

[0088] This comparative example provides a hot melt adhesive film, the preparation method of which includes the following steps:

[0089] (1) Weigh 7 kg of thermoplastic copolyamide (Arkema M 1276), 1 kg of thermoplastic copolyester (EMS ES500), and 2 kg of copper powder (50-60 μm) for later use. Mix the materials using a twin-screw extruder and cut the materials into granules. The extrusion temperature is 160-180℃.

[0090] (2) The mixture obtained in step (1) is added to a single screw extruder, extruded at 160-180℃ and formed into a film. After embossing, cooling, traction and winding processes, a hot melt adhesive film is prepared.

[0091] Comparative Example 3

[0092] This comparative example provides a hot melt adhesive film, the preparation method of which includes the following steps:

[0093] (1) Weigh 8 kg of thermoplastic copolyamide (Arkema M 1276) and 2 kg of copper powder (25-45 μm) for later use. Mix the materials using a twin-screw extruder and cut the materials into granules. The extrusion temperature is 160-180℃.

[0094] (2) The mixture obtained in step (1) is added to a single screw extruder, extruded at 160-180℃ and formed into a film. After embossing, cooling, traction and winding processes, a hot melt adhesive film is prepared.

[0095] Comparative Example 4

[0096] This comparative example provides a hot melt adhesive film, the preparation method of which includes the following steps:

[0097] (1) Weigh 6 kg of thermoplastic copolyamide (Arkema M 1276), 2 kg of thermoplastic polyurethane (Wanhua 6262), and 2 kg of copper powder (25-45 μm) for later use. Mix the materials using a twin-screw extruder and cut the materials into granules. The extrusion temperature is 160-180℃.

[0098] (2) The mixture obtained in step (1) is added to a single screw extruder, extruded at 160-180℃ and formed into a film. After embossing, cooling, traction and winding processes, a hot melt adhesive film is prepared.

[0099] Comparative Example 5

[0100] This comparative example provides a hot melt adhesive film, the preparation method of which includes the following steps:

[0101] (1) Weigh 6 kg of thermoplastic copolyamide (Arkema M 1276), 2 kg of thermoplastic copolyester (Fissati PES 386, melting point 147~157℃), and 2 kg of tin alloy powder Sn. 98.5 Ag1Cu 0.5 (25-45μm) is reserved. The material is mixed using a twin-screw extruder and cut into granules. The extrusion temperature is 160-180℃.

[0102] (2) The mixture obtained in step (1) is added to a single screw extruder, extruded at 160-180℃ and formed into a film. After embossing, cooling, traction and winding processes, a hot melt adhesive film is prepared.

[0103] Performance testing

[0104] The films prepared in the above embodiments and comparative examples were subjected to the following tests:

[0105] Encapsulation strength: The prepared adhesive film is used to encapsulate the card base and chip according to the normal card base encapsulation process. After encapsulation, the chip is left to stand for 2 hours, and the destructive thrust of the encapsulated chip is tested (the industry standard requires a thrust greater than 90N).

[0106] Conductivity test: After hot pressing, the chip is tested with non-contact electrical signals to check whether the automated test response of the chip is correct and whether the read and write functions are normal.

[0107] Ethanol resistance test: After 1000 cycles of card insertion / removal or three-round pressure test, the chip is half-immersed in 100% ethanol solution (half of the chip is below the liquid surface and half is above the liquid surface) for 12 hours to test whether the automated test response of the chip is correct and whether the read and write functions are normal.

[0108] The performance test results of the hot melt adhesive films provided in the above embodiments and comparative examples are shown in Table 1.

[0109] Table 1

[0110]

[0111] As can be seen, Examples 1 to 5 all exhibit good thrust, ranging from 102N to 125N. However, Comparative Example 1, using conductive materials with excessively small particle sizes, while achieving good encapsulation strength, failed to establish proper conductivity between the chip and the substrate, resulting in no electrical signal and making it impossible to test ethanol resistance. Comparative Example 2, using conductive materials with excessively large particle sizes, prevents proper polymer filling, potentially leading to localized aggregation, accelerated interfacial peeling, and poor bonding performance.

[0112] Comparative Example 3 uses a single thermoplastic copolyamide and conductive material. The cyclic stress generated causes microcracks in the conductive material and the interface with the colloid, and the conductive path gradually breaks down. It appears that good conductivity is formed after hot pressing, but the sealing performance decreases under repeated pressure and fails the ethanol resistance test.

[0113] When Comparative Examples 4 and 5 were replaced with thermoplastic polyurethane and copolyester, which are not within the scope of protection, the adhesive strength of the hot melt adhesive decreased significantly. It can be seen that only specific thermoplastic copolyamides combined with thermoplastic copolyesters have good compatibility and can form a stable conductive network with conductive materials to obtain hot melt adhesives with both good adhesive strength and ethanol resistance.

[0114] It is evident that the hot melt adhesive provided in this application utilizes thermoplastic copolyester to provide high-strength bonding and thermoplastic copolyamide to adjust flexibility as a resin matrix, and uses specific conductive materials to form a stable conductive network, thereby obtaining a hot melt adhesive that has both good adhesive thrust and ethanol resistance.

[0115] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A hot melt adhesive, characterized in that, By mass percentage, the composition includes 40% to 70% thermoplastic copolyamide, 10% to 30% thermoplastic copolyester, and 20% to 40% conductive material; The thermoplastic copolyamide has a melting point of 100℃~140℃, and the thermoplastic copolyester includes one or two of crystalline thermoplastic copolyesters with a melting point of 100℃~140℃ and amorphous thermoplastic copolyesters with a glass transition temperature of 5℃~30℃.

2. The hot melt adhesive as described in claim 1, characterized in that, The thermoplastic copolyamide includes one or more of Arkema HX2592, Arkema M1276, and Arkema H2519.

3. The hot melt adhesive as described in claim 1, characterized in that, The thermoplastic copolyester satisfies one or two of the following conditions: (1) The crystalline thermoplastic copolyester includes one or more of EMS ES500, EMS ES702, Festi PES E20 and Festi PES 3730. (2) The non-crystalline thermoplastic copolyester includes one or more of Toyobo 670, Toyobo 673 and Toyobo 630.

4. The hot melt adhesive according to any one of claims 1 to 3, characterized in that, The conductive material includes one or more of metallic copper, metallic tin, metallic silver, metallic copper, and metallic aluminum.

5. The hot melt adhesive according to any one of claims 1 to 3, characterized in that, The particle size of the conductive material is 25μm~45μm.

6. A method for preparing a hot melt adhesive, characterized in that, Includes the following steps: The raw materials are provided for the composition of the hot melt adhesive as described in any one of claims 1 to 5; The raw materials are mixed and extruded to prepare the hot melt adhesive.

7. The method for preparing hot melt adhesive as described in claim 6, characterized in that, The extrusion temperature is 160℃~180℃.

8. An anisotropic conductive adhesive film, characterized in that, The composition includes the hot melt adhesive as described in any one of claims 1 to 5.

9. The anisotropic conductive film as described in claim 8, characterized in that, The thickness is 40μm~60μm.

10. A smart card, characterized in that, It includes a substrate and a chip, wherein the substrate and the chip are encapsulated by the hot melt adhesive as described in any one of claims 1 to 5 or the anisotropic conductive film as described in claim 8 or 9.

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