Method for improving high-temperature stability of dimer acid type hot melt adhesive

Abstract

The invention belongs to the technical field of hot melt adhesives, and particularly relates to a high-temperature-resistant dimer acid type hot melt adhesive and a preparation method thereof. The high-temperature-resistant dimer acid type hot melt adhesive comprises the following components in parts by weight: 70-80 parts of hydrogenated dimer acid; 8 to 10 parts of functionalized glutaric acid; 10 to 15 parts of polyether amine; 5 to 10 parts of diamine; 0.1 to 0.12 part of a catalyst; the preparation method comprises the following steps: reacting benzimidazole chloride with amino glutaric acid to prepare functionalized glutaric acid; according to the high-temperature-resistant dimer acid type hot melt adhesive provided by the invention, hydrogenated dimer acid with better performance is taken as a main component, and the functional glutaric acid component is added, so that modification of the dimer acid type hot melt adhesive is realized, and finally, the high-temperature-resistant dimer acid type hot melt adhesive with good mechanical property, adhesive property, high-temperature stability and flame retardant property is obtained.

Description

Technical Field

[0001] This invention belongs to the field of hot melt adhesive technology, specifically relating to a high-temperature resistant dimer acid type hot melt adhesive and its preparation method. Background Technology

[0002] Dimer acid-type polyamide hot melt adhesive is a type of hot melt adhesive produced by the condensation reaction of dimer acid and diamine. It is the best performing hot melt adhesive currently available. The amide groups in dimer acid-type polyamide hot melt adhesive have good affinity with many materials. It is solid at room temperature and becomes liquid after reaching its melting point. In the molten state, it has fluidity and adhesive ability, which can quickly bond objects together. After cooling and solidification, it forms a high-strength bond. Because it is solid at room temperature, it can be made into blocks, films, strips or granules as needed. Packaging, storage, transportation and use are extremely convenient. No solvent is required during use, and there is no risk of solvent toxicity or flammability. Dimer acid-type hot melt adhesive can be widely used in road marking paint, automotive filters, heat shrinkable materials, leather, metal bonding, plastic bonding and other fields where other adhesives are difficult to use.

[0003] Chinese patent application number CN202010378899.6 discloses an environmentally friendly hot melt adhesive for cigarettes, comprising the following raw materials by weight percentage: 20-40% EVA resin, 3-10% modifier, 5-20% wax, 30-60% tackifying resin, 0.5-5% powder, 0.1-1% polyamide wax, and 0.1-1% antioxidant. The prepared hot melt adhesive is transparent and has advantages such as low adhesive permeability, good adhesion, rapid curing, and safety and environmental friendliness, but its high-temperature resistance is poor. Chinese patent application number CN202211481364.7 discloses a polyamide hot melt adhesive, comprising, by weight percentage... The product comprises the following components: 600-700 parts of diacid, 20-80 parts of diamine, 100-500 parts of polyetheramine, 10-50 parts of aminosulfonic acid, 10-50 parts of silicone oil, 20-200 parts of resin, 10-40 parts of antioxidant, 2-20 parts of catalyst, and 10-40 parts of colorant. The high-temperature resistance of the provided polyamide hot melt adhesive is superior to that of the above-mentioned hot melt adhesive with EVA resin as the main raw material. Similarly, by adding a certain proportion of antioxidant to the reaction system, the antioxidant performance of the hot melt adhesive during high-temperature application can be improved, but the high-temperature antioxidant performance of the final polyamide hot melt adhesive is still insufficient.

[0004] Hydrogenated dimer acid is obtained by reacting ordinary dimer acid or high-purity dimer acid with hydrogen under certain temperature and pressure conditions with a catalyst, thereby saturating the double bonds in the dimer acid with hydrogen. Hydrogenated dimer acid is more stable than ordinary dimer acid. Dimer acid-type hot melt adhesives generally use ordinary dimer acid (dimer acid content 80%) and high-purity dimer acid (dimer acid content above 95%) to react with amines. This invention uses hydrogenated dimer acid instead of ordinary dimer acid and high-purity dimer acid to react with amine compounds to obtain a dimer acid-type hot melt adhesive with excellent high-temperature stability. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a high-temperature resistant dimer acid type hot melt adhesive and its preparation method. The high-temperature resistant dimer acid type hot melt adhesive provided by this invention uses hydrogenated dimer acid with better performance as the main component. By adding functionalized glutaric acid components, the dimer acid type hot melt adhesive is modified, and finally a high-temperature resistant dimer acid type hot melt adhesive with good mechanical properties, bonding properties, high-temperature stability and flame retardant properties is obtained.

[0006] The technical solution adopted by the present invention to achieve the above objectives is as follows: A high-temperature resistant dimer acid type hot melt adhesive, the hot melt adhesive comprising the following components in parts by weight: 70-80 parts of hydrogenated dimer acid; 8-10 parts of functionalized glutaric acid; 10-15 parts of polyetheramine; 5-10 parts of diamine; and 0.1-0.12 parts of catalyst.

[0007] Furthermore, the diamine is any one or a mixture of several of ethylenediamine, hexamethylenediamine, and pentanediamine.

[0008] Furthermore, the catalyst is any one or a mixture of several of glacial acetic acid, propionic acid, and phosphoric acid.

[0009] Further, the functionalized glutaric acid is prepared by the following method: acetonitrile, benzimidazole chloride, aminoglutaric acid and N,N-diisopropylethylamine are added to a reaction vessel, stirred evenly, and placed at 60-70℃ for 4-5 h to obtain functionalized glutaric acid.

[0010] Furthermore, the molar ratio of benzimidazole chloride, aminoglutaric acid, and N,N-diisopropylethylamine is 1:1.1-1.2:1.2-1.3.

[0011] Further, the chlorobenzimidazole is prepared by the following method: S1. Add acetonitrile, 2-vinylbenzimidazole, styrene dichloride and triethylamine to the reaction vessel, stir well, and place at 50-60℃ for 5-6 hours to obtain vinylbenzimidazole chloride. S2. Add N,N-dimethylformamide, vinylbenzimidazole chloride and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to the reaction vessel, stir well, place at 90-100℃, and react for 9-10 hours to obtain benzimidazole chloride.

[0012] Further, the molar ratio of 2-vinylbenzimidazole, styrene dichloride, and triethylamine in step S1 is 1:1.1-1.2:1.2-1.3.

[0013] Further, in step S2, the molar ratio of vinylbenzimidazole chloride and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1:1.1-1.2.

[0014] This invention also provides a method for preparing a high-temperature resistant dimer acid type hot melt adhesive, comprising the following steps: according to the weight ratio, under nitrogen protection, adding hydrogenated dimer acid to a reaction vessel, heating to 130-150°C, adding polyetheramine and diamine, carrying out a heat preservation reaction, then heating to 240-250°C, adding functionalized glutaric acid and a catalyst, carrying out a polymerization reaction to obtain a dimer acid type hot melt adhesive.

[0015] Furthermore, the heat preservation reaction time is 1-2 hours.

[0016] Furthermore, the polymerization reaction time is 2-3 hours.

[0017] The present invention has the following beneficial effects: To obtain a high-temperature resistant dimer acid type hot melt adhesive, this invention modifies the components of the dimer acid type hot melt adhesive. First, 2-vinylbenzimidazole is used as a raw material and reacted sequentially with styrene dichloride 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) to obtain benzimidazole chloride. Then, benzimidazole chloride is reacted with aminoglutaric acid to obtain functionalized glutaric acid. The functionalized glutaric acid obtained by this invention contains both benzimidazole and DOPO structures. The benzimidazole structure exhibits good high-temperature aging resistance, while the DOPO structure provides high-temperature flame retardancy, effectively improving the performance of the dimer acid type hot melt adhesive. The flame retardant properties of the melt adhesive and the functionalized glutaric acid can work together to improve the high-temperature stability of dimer acid-type hot melt adhesives. Simultaneously, the polybenzene ring structure in the functionalized glutaric acid also helps to improve the mechanical properties and peel strength of dimer acid-type hot melt adhesives. In particular, the glutaric acid structure in the functionalized glutaric acid allows it to participate in the polymerization reaction of dimer acid-type hot melt adhesives. Introducing functionalized glutaric acid into the molecular structure of dimer acid-type hot melt adhesives directly modifies the molecular structure and maximizes the effect of the aforementioned functional structures, thereby endowing dimer acid-type hot melt adhesives with excellent mechanical properties, adhesion properties, high-temperature stability, and flame retardant properties.

[0018] The high-temperature resistant dimer acid hot melt adhesive provided by this invention uses hydrogenated dimer acid with better performance as the main component. By adding functionalized glutaric acid, the dimer acid hot melt adhesive is modified, and finally a high-temperature resistant dimer acid hot melt adhesive with good mechanical properties, bonding properties, high-temperature stability and flame retardant properties is obtained. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The technical features designed in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] In the technical solution of this invention, all chemical reagents used are commercially available, including: hydrogenated dimer acid (CAS: 68783-41-5), polyetheramine (CAS: 9046-10-0), ethylenediamine (CAS: 107-15-3), hexamethylenediamine (CAS: 124-09-4), pentanediamine (CAS: 462-94-2), glacial acetic acid (CAS: 64-19-7), propionic acid (CAS: 79-09-4), phosphoric acid (CAS: 7664-38-2), and 2-vinylbenzimidazole (CAS: 14984-2). 6-0, Styrene dichloride CAS: 1074-11-9, Triethylamine CAS: 121-44-8, 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) CAS: 35948-25-5, Aminoglutaric acid CAS: 56-86-0, N,N-Diisopropylethylamine CAS: 7087-68-5, Acetonitrile CAS: 75-05-8, N,N-Dimethylformamide CAS: 68-12-2, Ethanol CAS: 64-17-5.

[0021] Example 1 This embodiment provides a method for preparing benzimidazole chloride: ; S1. Add 500 mL of acetonitrile, 14.5 g of 2-vinylbenzimidazole, 19.4 g of styrene dichloride and 12.2 g of triethylamine to the reaction vessel, stir well, and react at 60 °C for 5 h. After the reaction is complete, remove the acetonitrile, and extract and concentrate to obtain 24.5 g of vinylbenzimidazole chloride; wherein the molar ratio of 2-vinylbenzimidazole, styrene dichloride and triethylamine is 1:1.1:1.2. Vinylbenzimidazole chloride: ESI (m / z): 283.8 [M+H] + , 1 H-NMR (600MHz, DMSO-d6, δppm): 7.78 (d, J=8.6Hz, 2H), 7.59-7.63 (m, 2H), 7.28-7.32 (m, 5H), 6.63-6.65 (m, 1H), 5.89-5.92 (m, 1H), 5.44-5.47 (m, 1H), 4.81-4.83 (m, 1H), 4.42-4.45 (m, 1H), 4.17-4.20 (m, 1H); S2. Add 500 mL of N,N-dimethylformamide, 24.5 g of vinylbenzimidazole chloride, and 20.6 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) to the reaction vessel, stir well, and place at 100 °C for 9 h. After the reaction is completed, extract and concentrate to obtain 35.8 g of benzimidazole chloride; wherein the molar ratio of vinylbenzimidazole chloride to 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1:1.1. Benzimidazole chloride: ESI (m / z): 499.9 [M+H] + , 1 H-NMR (600MHz, DMSO-d6, δppm): 8.00 (d, J=8.5Hz, 1H), 7.75 (d, J=8.4Hz, 1H), 7.49-7.53 (m, 4H), 7.36-7.41 (m, 5H), 7.27-7. 32 (m, 4H), 7.17-7.20 (m, 2H), 4.80-4.83 (m, 1H), 4.42-4.45 (m, 1H), 4.17-4.20 (m, 1H), 3.09-3.11 (m, 2H), 2.89-2.92 (m, 2H).

[0022] Example 2 This embodiment provides a method for preparing functionalized glutaric acid: ; 400 mL of acetonitrile, 35.8 g of benzimidazole chloride, 11.6 g of aminoglutaric acid, and 11.1 g of N,N-diisopropylethylamine were added to a reaction vessel, stirred until homogeneous, and reacted at 70 °C for 4 h. After the reaction was completed, the acetonitrile was removed, and the product was extracted and concentrated to obtain 38.2 g of functionalized glutaric acid. The molar ratio of benzimidazole chloride, aminoglutaric acid, and N,N-diisopropylethylamine was 1:1.1:1.2. Functionalized glutaric acid: ESI (m / z): 610.6 [M+H] + , 1H-NMR (600MHz, DMSO-d6, δppm): 12.39 (s, 2H), 8.02 (d, J=8.5Hz, 1H), 7.74 (d, J=8.4 Hz, 1H), 7.47-7.52 (m, 4H), 7.36-7.42 (m, 5H), 7.28-7.32 (m, 4H), 7.16-7.20 (m, 2H) , 4.26-4.31 (m, 1H), 4.16 (s, 1H), 4.01-4.06 (m, 1H), 3.90-3.94 (m, 1H), 3.40-3.42 ( m, 1H), 3.09-3.12 (m, 2H), 2.90-2.93 (m, 2H), 2.33-2.36 (m, 2H), 1.91-1.94 (m, 2H).

[0023] Example 3 This embodiment provides a high-temperature resistant dimer acid type hot melt adhesive, comprising the following components by weight: 80 parts of hydrogenated dimer acid; 10 parts of functionalized glutaric acid; 12 parts of polyetheramine; 10 parts of diamine; and 0.12 parts of catalyst; wherein the diamine is pentanediamine and the catalyst is glacial acetic acid.

[0024] This embodiment also provides a method for preparing a high-temperature resistant dimer acid type hot melt adhesive, including the following steps: according to the weight ratio, under nitrogen protection, hydrogenated dimer acid is added to a reaction vessel, the temperature is raised to 150°C, polyetheramine and diamine are added, the temperature is maintained for reaction, the temperature is then raised to 240°C, functionalized glutaric acid and catalyst are added, and a polymerization reaction is carried out to obtain a dimer acid type hot melt adhesive; wherein the reaction time is 1 hour; the polymerization reaction time is 3 hours.

[0025] Example 4 This embodiment provides a high-temperature resistant dimer acid type hot melt adhesive, comprising the following components by weight: 75 parts hydrogenated dimer acid; 9 parts functionalized glutaric acid; 10 parts polyetheramine; 8 parts diamine; and 0.11 parts catalyst; wherein the diamine is hexamethylenediamine and the catalyst is propionic acid.

[0026] This embodiment also provides a method for preparing a high-temperature resistant dimer acid type hot melt adhesive, including the following steps: according to the weight ratio, under nitrogen protection, hydrogenated dimer acid is added to a reaction vessel, the temperature is raised to 140°C, polyetheramine and diamine are added, the temperature is maintained for reaction, the temperature is then raised to 245°C, functionalized glutaric acid and catalyst are added, and a polymerization reaction is carried out to obtain a dimer acid type hot melt adhesive; wherein the reaction time is 1.5 h; the polymerization reaction time is 2.5 h.

[0027] Example 5 This embodiment provides a high-temperature resistant dimer acid type hot melt adhesive, comprising the following components by weight: 70 parts hydrogenated dimer acid; 8 parts functionalized glutaric acid; 15 parts polyetheramine; 5 parts diamine; and 0.1 parts catalyst; wherein the diamine is ethylenediamine and the catalyst is phosphoric acid.

[0028] This embodiment also provides a method for preparing a high-temperature resistant dimer acid type hot melt adhesive, including the following steps: according to the weight ratio, under nitrogen protection, hydrogenated dimer acid is added to a reaction vessel, the temperature is raised to 130°C, polyetheramine and diamine are added, the temperature is maintained for reaction, the temperature is then raised to 250°C, functionalized glutaric acid and catalyst are added, and a polymerization reaction is carried out to obtain a dimer acid type hot melt adhesive; wherein the reaction time is 2 hours; the polymerization reaction time is 2 hours.

[0029] Example 6 This embodiment provides a high-temperature resistant dimer acid type hot melt adhesive, comprising the following components by weight: 80 parts hydrogenated dimer acid; 9 parts functionalized glutaric acid; 10 parts polyetheramine; 9 parts diamine; and 0.11 parts catalyst; wherein the diamine is ethylenediamine and the catalyst is propionic acid.

[0030] This embodiment also provides a method for preparing a high-temperature resistant dimer acid type hot melt adhesive, including the following steps: according to the weight ratio, under nitrogen protection, hydrogenated dimer acid is added to a reaction vessel, the temperature is raised to 140°C, polyetheramine and diamine are added, the temperature is maintained for reaction, the temperature is then raised to 250°C, functionalized glutaric acid and catalyst are added, and a polymerization reaction is carried out to obtain a dimer acid type hot melt adhesive; wherein the reaction time is 2 hours; the polymerization reaction time is 2.5 hours.

[0031] Comparative Example 1 This comparative example provides a high-temperature resistant dimer acid type hot melt adhesive, comprising the following components in parts by weight: 80 parts hydrogenated dimer acid; 10 parts chlorinated vinylbenzimidazole; 12 parts polyetheramine; 10 parts diamine; and 0.12 parts catalyst; wherein the diamine is pentanediamine and the catalyst is glacial acetic acid.

[0032] This comparative example also provides a method for preparing a high-temperature resistant dimer acid type hot melt adhesive, comprising the following steps: according to the weight ratio, under nitrogen protection, hydrogenated dimer acid is added to a reaction vessel, the temperature is raised to 150°C, polyetheramine and diamine are added, the temperature is maintained for reaction, the temperature is then raised to 240°C, vinylbenzimidazole chloride and catalyst are added, and a polymerization reaction is carried out to obtain a dimer acid type hot melt adhesive; wherein the reaction time is 1 hour; the polymerization reaction time is 3 hours.

[0033] Comparative Example 2 This comparative example provides a high-temperature resistant dimer acid type hot melt adhesive, comprising the following components by weight: 80 parts hydrogenated dimer acid; 10 parts chlorobenzimidazole; 12 parts polyetheramine; 10 parts diamine; and 0.12 parts catalyst; wherein the diamine is pentanediamine and the catalyst is glacial acetic acid.

[0034] This comparative example also provides a method for preparing a high-temperature resistant dimer acid type hot melt adhesive, comprising the following steps: according to the weight ratio, under nitrogen protection, hydrogenated dimer acid is added to a reaction vessel, the temperature is raised to 150°C, polyetheramine and diamine are added, the temperature is maintained for reaction, the temperature is then raised to 240°C, chlorobenzimidazole and catalyst are added, and a polymerization reaction is carried out to obtain a dimer acid type hot melt adhesive; wherein the reaction time is 1 hour; the polymerization reaction time is 3 hours.

[0035] Comparative Example 3 This comparative example provides a high-temperature resistant dimer acid type hot melt adhesive, comprising the following components by weight: 80 parts hydrogenated dimer acid; 10 parts aminoglutaric acid; 12 parts polyetheramine; 10 parts diamine; and 0.12 parts catalyst; wherein the diamine is pentanediamine and the catalyst is glacial acetic acid.

[0036] This comparative example also provides a method for preparing a high-temperature resistant dimer acid type hot melt adhesive, comprising the following steps: according to the weight ratio, under nitrogen protection, hydrogenated dimer acid is added to a reaction vessel, the temperature is raised to 150°C, polyetheramine and diamine are added, the temperature is maintained for reaction, the temperature is then raised to 240°C, aminoglutaric acid and catalyst are added, and a polymerization reaction is carried out to obtain a dimer acid type hot melt adhesive; wherein the reaction time is 1 hour; the polymerization reaction time is 3 hours.

[0037] Test case The performance of the dimer acid-type hot melt adhesives provided in Examples 3 to 6 and Comparative Examples 1 to 3 was tested. The viscosity test was conducted according to HG / T 3660-1999 standard; the softening point test was conducted according to GB / T 15332-1994 standard; the tensile strength test was conducted according to GB / T 7124-2008 standard; the T-peel strength test was conducted according to GB / T2790-1995 standard; the high temperature stability test was conducted by placing the adhesive sample vertically at 220℃ and holding it at that temperature for 4 hours, observing whether there was any sagging or dripping of the adhesive layer; the limiting oxygen index was conducted according to GB / T2406-2009 standard; the results are shown in Table 1 below.

[0038] Table 1 As shown in Table 1, the dimer acid-type hot melt adhesives provided in Examples 3 to 6 of this invention exhibit better viscosity, softening point, tensile strength, T-peel strength, high-temperature stability, and limiting oxygen index than Comparative Examples 1 to 3. This indicates that the dimer acid-type hot melt adhesives provided in this invention possess excellent mechanical properties, adhesive properties, high-temperature stability, and flame retardant properties. Comparing Example 3 with Comparative Examples 1 to 3, it can be seen that the dimer acid-type hot melt adhesive in Example 3 of this invention includes functionalized glutaric acid, which contains a benzimidazole structure and a DOPO structure. The benzimidazole structure exhibits good high-temperature aging resistance, and the DOPO structure... The structure possesses high-temperature resistance and flame retardancy, effectively improving the flame retardant properties of dimer acid-based hot melt adhesives. Both components work together to enhance the high-temperature stability of dimer acid-based hot melt adhesives. The polybenzene ring structure contained in functionalized glutaric acid helps improve the mechanical properties and peel strength of dimer acid-based hot melt adhesives. In particular, the glutaric acid structure in functionalized glutaric acid enables it to participate in the polymerization reaction of dimer acid-based hot melt adhesives. Introducing functionalized glutaric acid into the molecular structure of dimer acid-based hot melt adhesives allows the aforementioned structure to exert its maximum effect, thereby endowing dimer acid-based hot melt adhesives with excellent mechanical properties, adhesive properties, high-temperature stability, and flame retardant properties.

[0039] It should be noted that, in this document, terms such as "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-temperature resistant dimer acid type hot melt adhesive, characterized in that, The hot melt adhesive comprises the following components in parts by weight: 70-80 parts hydrogenated dimer acid; 8-10 parts functionalized glutaric acid; 10-15 parts polyetheramine; 5-10 parts diamine; and 0.1-0.12 parts catalyst. The functionalized glutaric acid is prepared by the following method: acetonitrile, benzimidazole chloride, aminoglutaric acid and N,N-diisopropylethylamine are added to a reaction vessel, stirred evenly, and placed at 60-70℃ for 4-5 hours to obtain functionalized glutaric acid.

2. The high-temperature resistant dimer acid type hot melt adhesive according to claim 1, characterized in that, The chlorobenzimidazole was prepared by the following method: S1. Add acetonitrile, 2-vinylbenzimidazole, styrene dichloride and triethylamine to the reaction vessel, stir well, and place at 50-60℃ for 5-6 hours to obtain vinylbenzimidazole chloride. S2. Add N,N-dimethylformamide, vinylbenzimidazole chloride and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to the reaction vessel, stir well, place at 90-100℃, and react for 9-10 hours to obtain benzimidazole chloride.

3. The high-temperature resistant dimer acid type hot melt adhesive according to claim 2, characterized in that, The molar ratio of 2-vinylbenzimidazole, styrene dichloride, and triethylamine in step S1 is 1:1.1-1.2:1.2-1.

3.

4. The high-temperature resistant dimer acid type hot melt adhesive according to claim 2, characterized in that, The molar ratio of vinylbenzimidazole chloride and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in step S2 is 1:1.1-1.

2.

5. The high-temperature resistant dimer acid type hot melt adhesive according to claim 1, characterized in that, The molar ratio of benzimidazole chloride, aminoglutaric acid, and N,N-diisopropylethylamine is 1:1.1-1.2:1.2-1.

3.

6. The high-temperature resistant dimer acid type hot melt adhesive according to claim 1, characterized in that, The diamine is any one or a mixture of several of ethylenediamine, hexamethylenediamine, and pentanediamine.

7. The high-temperature resistant dimer acid type hot melt adhesive according to claim 1, characterized in that, The catalyst is any one or a mixture of several of glacial acetic acid, propionic acid, and phosphoric acid.

8. A method for preparing a high-temperature resistant dimer acid type hot melt adhesive as described in any one of claims 1-7, characterized in that, The process includes the following steps: According to the weight ratio, under nitrogen protection, add hydrogenated dimer acid to the reaction vessel, heat to 130-150℃, add polyetheramine and diamine, carry out the heat preservation reaction, then heat to 240-250℃, add functionalized glutaric acid and catalyst, carry out the polymerization reaction, and obtain dimer acid type hot melt adhesive.

9. The method for preparing a high-temperature resistant dimer acid type hot melt adhesive according to claim 8, characterized in that, The heat preservation reaction time is 1-2 hours.

10. The method for preparing a high-temperature resistant dimer acid type hot melt adhesive according to claim 8, characterized in that, The polymerization reaction time is 2-3 hours.

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