Copolyamide hot melt adhesive for bonding low-surface-energy fabric and preparation method of copolyamide hot melt adhesive

Abstract

The invention belongs to the technical field of polyamide hot melt adhesives, and particularly relates to a copolyamide hot melt adhesive for bonding a low-surface-energy fabric and a preparation method of the copolyamide hot melt adhesive. A low-surface-energy flexible organic silicon system and an alicyclic rigid group are introduced into a dimer acid type polyamide system at the same time, so that the prepared copolyamide hot melt adhesive product has high cohesive force, adhesive strength and low-surface-energy performance; the problems that an existing copolyamide hot melt adhesive is complex in preparation process and has limitation in the aspect of environmental protection are solved. Compared with a traditional copolyamide hot melt adhesive, the copolyamide hot melt adhesive has the advantages of being environmentally friendly, resistant to water washing and resistant to low temperature while maintaining high adhesive performance, and the performance of a product is greatly improved through the beneficial effects; the product has high matching degree with the customer process, the polymerization process is simple and efficient, the production is convenient, and the economic value is good.

Description

Technical Field

[0001] The invention belongs to the technical field of polyamide hot melt adhesives, and specifically relates to a copolyamide hot melt adhesive for bonding low surface energy fabrics and a preparation method thereof. Background Art

[0002] Copolyamide hot melt adhesive is widely used in textile and footwear industries, especially in the bonding process of lining fabrics and fabrics, uppers and vamps. In recent years, with the development of technology and the increase in consumer demand, the bonding of water-repellent, breathable and impermeable fabrics has become a technical problem in the industry. At present, most of the methods on the market use oil glue or sol to bond such fabrics, but these methods are insufficient in terms of environmental protection and urgently need to be improved.

[0003] Water-repellent, breathable and impermeable fabrics are generally non-polar substrates. According to the principle of similar compatibility, low-polarity adhesives should be selected for bonding non-polar substrates in theory, such as APAO, EVA, PP and other polyolefin adhesives. However, the cohesive strength of these low-polarity adhesives is generally lower than that of high-polarity adhesives, that is, the cohesive strength of APAO, EVA, PP and other polyolefin adhesives is far from the level of traditional copolyamide, copolyester, and polyurethane adhesives.

[0004] In order to enable traditional copolyamide, copolyester, and polyurethane adhesives to bond non-polar substrates, it is often necessary to introduce a non-polar system. For example, the patent with publication number CN105111449A discloses a method for preparing a thermoplastic silicone / polyamide elastic composition by directly copolymerizing a functional end group-containing silicone and a functional end group-containing polyamide. However, due to the large difference in polarity between the two, it is necessary to add meta-cresol and xylene as solvents in the system. Although this method can combine the performance advantages of both, the addition of solvents is not environmentally friendly and increases the complexity of the process. In addition, the patent with publication number CN101386681B discloses an in-situ preparation method of a hydrophobic silicone / polyamide 6 block copolymer. The method performs a reaction of ε-caprolactam-terminated isocyanate groups at a relatively high temperature to prepare an ε-caprolactam anionic polymerization cocatalyst, and finally adds an anionic polymerization catalyst to polymerize the remaining ε-caprolactam at a set temperature to obtain a hydrophobic silicone / polyamide 6 block copolymer. However, the reaction process is complicated, and it is difficult to remove the catalyst in the later stage.

[0005] Therefore, the products prepared by the above two methods cannot be used as adhesives to effectively bond substrates; the existing copolyamide hot melt adhesive preparation technology has certain limitations in terms of environmental protection, bonding strength and process complexity. Summary of the invention

[0006] In view of the problems existing in the prior art, the present invention proposes a copolyamide hot melt adhesive for bonding low surface energy fabrics and a preparation method thereof, with the purpose of introducing a low surface energy flexible silicone system and an alicyclic rigid group into a dimer acid type polyamide system at the same time, so that the prepared copolyamide hot melt adhesive product has high cohesion, adhesion and low surface energy properties; and solves the problem that the preparation process of the existing copolyamide hot melt adhesive is complicated and has limitations in environmental protection.

[0007] The present invention discloses a method for preparing a copolyamide hot melt adhesive for bonding low surface energy fabrics, comprising:

[0008] (1) adding aliphatic lactam, dibasic acid, diamine, molecular weight regulator, catalyst, antioxidant, lactam ring-opening catalyst and water into a reaction kettle, wherein the molar ratio of aliphatic lactam: dibasic acid: diamine is 0.2-0.45:1:0.8-0.9;

[0009] (2) After the feeding is completed, the reactor is replaced with nitrogen three times, and the temperature is slowly raised to 130°C. Stirring is started, and the temperature is continued to rise to 190°C after the system is homogeneous. The pressure in the reactor is maintained at 1.5±0.05MPa, and the temperature is continued to rise. The reaction is carried out at 260±5°C for 1.5h;

[0010] (3) releasing the reaction kettle to normal pressure, maintaining the temperature in the kettle at 255° C. to 265° C., stirring and depressurizing for 1 hour, evacuating to a vacuum degree of <200 Pa, and maintaining the temperature at 250° C. to 260° C. for condensation reaction for 0.5 to 1 hour to obtain a carboxyl-terminated polyamide oligomer;

[0011] (4) adding an isocyanate-terminated silicone component into the reaction kettle, wherein the molar ratio of the isocyanate-terminated silicone component to the carboxyl-terminated polyamide oligomer produced in step (3) is 1-1.5:1, and the chemical formula of the reaction between the two is:

[0012]

[0013] Wherein R is linear organosiloxane, R' is aliphatic polyamide with linear and alicyclic main chains; the reaction is stirred at 230±5° C. for 1 hour, and the copolyamide hot melt adhesive for bonding low surface energy fabrics is obtained.

[0014] Further, the aliphatic lactam is caprolactam or laurolactam;

[0015] Furthermore, the dibasic acid is a mixture of dimer acid and other aliphatic dibasic acids, and the molar ratio of dimer acid to other aliphatic dibasic acids is 0.2-0.6:0.8-0.4; the other aliphatic dibasic acid is at least one of adipic acid, sebacic acid, dodecanedioic acid, tridecanedioic acid and tetradecanedioic acid;

[0016] Further, the diamine is made of aliphatic diamine and alicyclic diamine in a molar ratio of 1-3:1;

[0017] Furthermore, the aliphatic diamine is selected from at least one of methylpentanediamine, hexanediamine, decanediamine, and dodecanediamine; the alicyclic diamine is selected from 1,3-cyclohexanedimethylamine (HXDA), 4,4'-diaminodicyclohexylmethane (PACM), bis(3-methyl-4-aminocyclohexyl)methane (DMDC), 2,2'-bis(3-methyl-4-aminocyclohexyl)propane, bis(3-methyl-5-ethyl-4-aminocyclohexyl)methane, bis(3,5-dimethyl-4-aminocyclohexyl)methane, bis(3,5-dimethyl-4-aminocyclohexyl)methane, At least one of bis(2,3-dimethyl-4-aminocyclohexyl)propane, bis(2,3-dimethyl-4-aminocyclohexyl)methane, bis(2,3-dimethyl-4-aminocyclohexyl)propane, bis(3,5-diethyl-4-aminocyclohexyl)methane, bis(3,5-diethyl-4-aminocyclohexyl)propane, bis(3-methyl-5-isopropyl-4-aminocyclohexyl)methane and bis(3-methyl-5-isopropyl-4-aminocyclohexyl)propane; wherein 4,4'-diaminodicyclohexylmethane (PACM) and bis(3-methyl-4-aminocyclohexyl)methane (DMDC) are preferred;

[0018] Furthermore, the molecular weight regulator is stearic acid, and its addition amount is 1%-3% of the total mass of the aliphatic lactam, the dibasic acid and the diamine; the catalyst is phosphoric acid or phosphorous acid, and its addition amount is 0.03%-0.05% of the total mass of the aliphatic lactam, the dibasic acid and the diamine; the brand of the antioxidant is 1010, 168, 1098 or S-682, and its addition amount is 0.02% of the total mass of the aliphatic lactam, the dibasic acid and the diamine. %-0.05%; the lactam ring-opening polymerization adopts an acid-catalyzed ring-opening method, the lactam ring-opening catalyst is selected from an aqueous inorganic acid, ω-amino acid or polyamide salt, and its addition amount is 0.03%-0.05% of the total mass of the aliphatic lactam, the dibasic acid and the diamine, wherein the aqueous inorganic acid is at least one of sulfuric acid, phosphoric acid, phosphorous acid, boric acid and metaboric acid; the amount of water added is 15%-25% of the total mass of the aliphatic lactam, the dibasic acid and the diamine.

[0019] Furthermore, the isocyanate-terminated silicone component is composed of hydroxyl-terminated silicone oil, diisocyanate and a catalyst, wherein the molar ratio of the hydroxyl-terminated silicone oil to the diisocyanate is 1:3-3.1; the excess diisocyanate can ensure the reaction with the carboxyl-terminated polyamide oligomer to generate a new amide bond; the preparation method of the isocyanate-terminated silicone component includes:

[0020] (1) Dehydrating the hydroxyl-terminated silicone oil at 140° C. and vacuum degree ≤-0.098 MPa until the water content is ≤500 ppm;

[0021] (2) Cooling to 100°C, adding diisocyanate, stirring and mixing evenly, and then heating to 120°C for reaction for 1 hour;

[0022] (3) adding a catalyst, performing a vacuum degassing reaction at 120° C. for 0.5 h, and obtaining an isocyanate-terminated organic silicon component;

[0023] Furthermore, the hydroxyl-terminated organic silicone oil is a polydimethylsiloxane terminated with double-terminal ether hydroxyl groups or double-terminal hydrocarbon hydroxyl groups, and has a molecular weight of 1000-3000 g / mol;

[0024] Further, the diisocyanate is one of hexamethyl diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, and 4,4'-diphenylmethane diisocyanate;

[0025] Furthermore, the catalyst is an organic metal or an organic tertiary amine, wherein the organic metal is preferably an organic tin catalyst, such as dimethyl tin oxide, dipropyl tin oxide, dibutyl tin oxide, trihexyl tin oxide, dibutyl tin dilaurate, diphenol tin oxide, trinaphthyl tin oxide, butylphenyl tin oxide, dibutylpropyl tin oxide or tributyl tin oxide, and more preferably dibutyl tin dilaurate; the organic tertiary amine is preferably triethylamine, triethylenediamine or stannous octoate plus triethylenediamine; and the added amount is 0.01%-0.03% of the total mass of the diisocyanate and the terminal hydroxyl silicone oil.

[0026] In the system of the present invention, if the ratio of aliphatic diamine to alicyclic diamine, and the ratio of dibasic acid to diamine are beyond the range, it will have an adverse effect on the aging resistance and bonding strength of the product, and will also affect the processing and transportation performance of the glue.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The present invention simultaneously introduces a low surface energy flexible silicone system and an alicyclic rigid group into a dimer acid type polyamide system, so that the obtained copolyamide hot melt adhesive not only maintains high cohesion and adhesion, but also has the low surface energy characteristics of silicone. That is, the copolyamide hot melt adhesive prepared by the present invention exhibits a bonding effect that is significantly better than that of traditional copolyamide hot melt adhesives when used for bonding low surface energy fabrics.

[0029] 2. The dimer acid component in the system of the present invention effectively improves the compatibility of the silicone and polyamide systems, which not only enhances the interaction between the two materials, but also improves the overall performance of the materials, making the application of copolyamide hot melt adhesive on low surface energy fabrics more extensive and reliable.

[0030] 3. The present invention utilizes highly reactive isocyanate groups to connect the two systems of silicone and polyamide through chemical bonds. This connection method not only improves the bonding strength, but also enhances the durability of the material, so that the copolyamide hot melt adhesive can maintain stable performance in various application environments.

[0031] Therefore, compared with traditional copolyamide hot melt adhesives, the copolyamide hot melt adhesive of the present invention has the advantages of environmental protection, water washability and low temperature resistance while maintaining high bonding performance. These beneficial effects greatly improve the performance of the product; the product has a high degree of matching with customer processes, and the polymerization process is simple and efficient, easy to produce, and has good economic value. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the infrared spectrum of the copolyamide hot melt adhesive obtained in Example 1. DETAILED DESCRIPTION

[0033] In order to better understand the content of the present invention, the present invention will be further described below in conjunction with specific examples. The following examples are based on the technology of the present invention and provide detailed implementation methods and operating steps, but the protection scope of the present invention is not limited to the following examples, that is, based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0034] Meanwhile, in each embodiment of the present invention, there is no special restriction on the source of each material, and commercially available products known to those skilled in the art and meeting the relevant property requirements may be used.

[0035] Example 1

[0036] The raw material composition (as shown in Table 1) and the specific preparation method of the copolyamide hot melt adhesive prepared in this embodiment are as follows, and the obtained product is marked as A1:

[0037] Table 1

[0038]

[0039] (1) 22.63 g of caprolactam, 112.18 g of dimer acid, 43.84 g of adipic acid, 115.15 g of dodecanedioic acid, 46.48 g of hexamethylenediamine, 84.15 g of 4,4'-diaminodicyclohexylmethane (PACM), 8.2 g of stearic acid, 79.23 g of water, 0.15 g of antioxidant (grade 1010), 0.15 g of phosphoric acid, and 0.15 g of phosphorous acid were added into a high-pressure reactor equipped with digital control heating;

[0040] (2) After the feeding is completed, nitrogen is used for replacement 3 times, and then the reactor is slowly heated to 130°C, stirring is started, and the temperature is continued to rise to 190°C. During this period, the pressure is kept rising. When the pressure reaches 1.5MPa, the pressure is maintained between 1.45 and 1.55MPa, and the temperature is kept between 255 and 265°C for 1.5h;

[0041] (3) The reactor was placed at normal pressure, the temperature was maintained between 255°C and 265°C, and the reaction was stirred for 1 hour. The pressure in the reactor was removed, and the vacuum was evacuated to a vacuum degree of <200 Pa, and then the polycondensation reaction was carried out at 255°C for 1 hour.

[0042] (4) adding an isocyanate-terminated silicone component, stirring and reacting at a temperature of 230° C. for 1 h, breaking the vacuum, and discharging the material under nitrogen protection to form strips, pelletize, and dry to obtain a copolyamide hot melt adhesive.

[0043] The preparation of the isocyanate-terminated silicone component is carried out according to the following steps and feeding ratios:

[0044] a. Dehydrate 1200 g (1.2 mol) of hydroxyl-terminated silicone oil (molecular weight 1000) at 140°C and vacuum degree ≤-0.098 MPa for 1 h, and the water content after dehydration is ≤500 ppm;

[0045] b. Cool to 100°C, then add 605.49 g (3.6 mol) of hexamethyl diisocyanate, stir and mix well, then heat to 120°C and react for 1 h;

[0046] c. Add 0.2 g of dibutyltin dilaurate as a catalyst, carry out vacuum degassing reaction at 120° C. for 0.5 h, and obtain the isocyanate-terminated silicone component after discharging.

[0047] Example 2

[0048] Compared with Example 1, the diisocyanate in the isocyanate-terminated silicone component of this embodiment is selected as 4,4'-diphenylmethane diisocyanate (MDI) 900.93g (3.6mol), and the other preparation steps are the same; the specific raw materials and the mass of each raw material are shown in Table 2, and the obtained product is marked as A2.

[0049] Table 2

[0050]

[0051] Example 3

[0052] Compared with Example 2, the aliphatic dibasic acids in this example are adipic acid, sebacic acid and dodecanedioic acid; the other preparation steps are the same; the specific raw materials and the mass of each raw material are shown in Table 3, and the obtained product is marked as A3.

[0053] Table 3

[0054]

[0055] Example 4

[0056] Compared with Example 3, the raw material quality of this example is shown in Table 4; the raw material types and preparation steps are the same; the obtained product is marked as A4

[0057] Table 4

[0058]

[0059]

[0060] Example 5

[0061] Compared with Example 4, the raw material quality of this example is shown in Table 5; the raw material types and preparation steps are the same; the obtained product is marked as A5;

[0062] Table 5

[0063]

[0064] Example 6

[0065] Compared with Example 4, the raw material quality of this example is shown in Table 6; the raw material types and preparation steps are the same; the obtained product is marked as A6;

[0066] Table 6

[0067]

[0068]

[0069] Comparative Example 1

[0070] Compared with Example 5, the present embodiment does not add the isocyanate-terminated organic silicon component; after the polycondensation reaction in step (3) for 1 hour, the vacuum is broken, and the product B1 is obtained after the material is pulled into strips, pelletized, and dried under nitrogen protection; the masses of the raw materials are shown in Table 7;

[0071] Table 7

[0072]

[0073] Performance Testing

[0074] The products A1-A6 obtained in the above examples 1-6 and the product B1 obtained in comparative example 1 were subjected to relevant performance tests. Among them, the melting point test standard reference: GB / T19466-2004; the melt index test standard reference: GB / T3682-2000, the test temperature is 160°C; the peel strength test standard reference: GB / T11402-1989, the pressing temperature is 140°C, pressure; the water washing performance test standard reference: FZ / T80007.2-2006. The test results are shown in Table 8.

[0075] Table 8

[0076]

[0077]

[0078] It can be seen that the copolyamide hot melt adhesives prepared by Examples 1-6 have excellent bonding strength when applied to low surface energy materials such as fluorine-silicon treatment, and their peel strength generally exceeds 35N / 2.5cm; and the peel strength loss rate after washing at 90°C does not exceed 20%. The water contact angle test shows that the value of the comparative sample B1 is 75°, and the values ​​of Examples A1-A6 are all above 130°. From the infrared spectrum of the product of Example 1 Figure 1 The characteristic peaks of polyamide and organosiloxane can be seen, indicating that the two react to obtain the target product.

[0079] Compared with Comparative Example 1, in the same formulation system, adding alicyclic and linear silicones within a certain range can effectively improve the peel strength and water washability of the prepared copolyamide hot melt adhesive to low surface energy materials.

[0080] In addition, after the copolyamide hot melt adhesive prepared by the present invention is applied to low surface energy materials, its peel strength is significantly higher than that of similar products on the market, among which the peel strength of fluorosilicone treated low surface energy fabrics can reach up to 41N / 2.5cm; and in contrast, similar HMPA products on the market have poor water washing resistance, and finally detach directly after washing, and its insufficient interface wetting will lead to interface damage, and the bonded low surface energy material film can be easily torn off.

[0081] Based on this, the copolyamide hot melt adhesive for bonding low surface energy fabrics of the present invention has a more superior bonding effect and better water washability than the traditional copolyamide hot melt adhesive. In addition, the product prepared by the present invention can withstand low temperatures, has a high degree of matching with the customer's process, and the polymerization process is simple and efficient, which is easy to produce.

[0082] The present invention can have other forms of embodiments according to the above preparation method, which are not listed one by one. Therefore, any simple modification, equivalent change and modification made to the above embodiments by any technician familiar with the profession according to the technical essence of the present invention without departing from the scope of the technical solution of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a copolyamide hot melt adhesive for bonding low surface energy fabrics, characterized in that: The following steps are involved: (1) adding aliphatic lactam, dibasic acid, diamine, molecular weight regulator, catalyst, antioxidant, lactam ring-opening catalyst and water into a reaction kettle, wherein the molar ratio of aliphatic lactam: dibasic acid: diamine is 0.2-0.45:1:0.8-0.9; (2) After the feeding is completed, the reactor is replaced with nitrogen three times, and the temperature is slowly raised to 130°C. Stirring is started, and the temperature is continued to rise to 190°C after the system is homogeneous. The pressure in the reactor is maintained at 1.5±0.05MPa, and the temperature is continued to rise. The reaction is carried out at 260±5°C for 1.5h; (3) releasing the reaction kettle to normal pressure, maintaining the temperature in the kettle at 255° C. to 265° C., stirring and depressurizing for 1 hour, evacuating to a vacuum degree of <200 Pa, and maintaining the temperature at 250° C. to 260° C. for condensation reaction for 0.5 to 1 hour to obtain a carboxyl-terminated polyamide oligomer; (4) adding an isocyanate-terminated silicone component into a reaction kettle, wherein the molar ratio of the isocyanate-terminated silicone component to the carboxyl-terminated polyamide oligomer produced in step (3) is 1-1.5:1; stirring the reaction at 230±5° C. for 1 hour, and discharging the material to obtain a copolyamide hot melt adhesive for bonding low surface energy fabrics.

2. The method for preparing a copolyamide hot melt adhesive for bonding low surface energy fabrics according to claim 1, characterized in that: The aliphatic lactam is caprolactam or laurolactam.

3. The method for preparing a copolyamide hot melt adhesive for bonding low surface energy fabrics according to claim 1, characterized in that: The dibasic acid is a mixture of dimer acid and other aliphatic dibasic acids, and the molar ratio of dimer acid to other aliphatic dibasic acids is 0.2-0.6:0.8-0.4; the other aliphatic dibasic acid is at least one of adipic acid, sebacic acid, dodecanedioic acid, tridecanedioic acid and tetradecanedioic acid.

4. The method for preparing a copolyamide hot melt adhesive for bonding low surface energy fabrics according to claim 1, characterized in that: The diamine is prepared from an aliphatic diamine and an alicyclic diamine in a molar ratio of 1-3:

1.

5. The method for preparing a copolyamide hot melt adhesive for bonding low surface energy fabrics according to claim 4, characterized in that: The aliphatic diamine is selected from at least one of methylpentanediamine, hexanediamine, decanediamine, and dodecanediamine; the alicyclic diamine is selected from 1,3-cyclohexanedimethylamine (HXDA), 4,4'-diaminodicyclohexylmethane (PACM), bis(3-methyl-4-aminocyclohexyl)methane (DMDC), 2,2'-bis(3-methyl-4-aminocyclohexyl)propane, bis(3-methyl-5-ethyl-4-aminocyclohexyl)methane, bis(3,5-dimethyl-4-aminocyclohexyl)methane, At least one of bis(3,5-dimethyl-4-aminocyclohexyl)methane, bis(3,5-dimethyl-4-aminocyclohexyl)propane, bis(2,3-dimethyl-4-aminocyclohexyl)methane, bis(2,3-dimethyl-4-aminocyclohexyl)propane, bis(3,5-diethyl-4-aminocyclohexyl)methane, bis(3,5-diethyl-4-aminocyclohexyl)propane, bis(3-methyl-5-isopropyl-4-aminocyclohexyl)methane and bis(3-methyl-5-isopropyl-4-aminocyclohexyl)propane.

6. The method for preparing a copolyamide hot melt adhesive for bonding low surface energy fabrics according to claim 1, characterized in that: The molecular weight regulator is stearic acid, and its addition amount is 1%-3% of the total mass of the aliphatic lactam, dibasic acid and diamine; the catalyst is phosphoric acid or phosphorous acid, and its addition amount is 0.03%-0.05% of the total mass of the aliphatic lactam, dibasic acid and diamine; the brand of the antioxidant is 1010, 168, 1098 or S-682, and its addition amount is 0.02%-0.05% of the total mass of the aliphatic lactam, dibasic acid and diamine; the lactam ring-opening polymerization adopts an acid-catalyzed ring-opening method, and the lactam ring-opening catalyst is selected from aqueous inorganic acid, ω-amino acid or polyamide salt, and its addition amount is 0.03%-0.05% of the total mass of the aliphatic lactam, dibasic acid and diamine, wherein the aqueous inorganic acid is at least one of sulfuric acid, phosphoric acid, phosphorous acid, boric acid and metaboric acid; the amount of water added is 15%-25% of the total mass of the aliphatic lactam, dibasic acid and diamine.

7. The method for preparing a copolyamide hot melt adhesive for bonding low surface energy fabrics according to claim 1, characterized in that: The isocyanate-terminated silicone component is composed of hydroxyl-terminated silicone oil, diisocyanate and a catalyst, wherein the molar ratio of the hydroxyl-terminated silicone oil to the diisocyanate is 1:3-3.1; The preparation method of the isocyanate-terminated silicone component comprises: (1) Dehydrating the hydroxy-terminated silicone oil at 140° C. and vacuum degree ≤-0.098 MPa until the water content is ≤500 ppm; (2) Cooling to 100°C, adding diisocyanate, stirring and mixing evenly, and then heating to 120°C for reaction for 1 hour; (3) Add a catalyst and carry out a vacuum degassing reaction at 120° C. for 0.5 h to obtain an isocyanate-terminated organic silicon component.

8. The method for preparing a copolyamide hot melt adhesive for bonding low surface energy fabrics according to claim 7, characterized in that: The terminal hydroxyl organic silicone oil is a polydimethylsiloxane terminated with double-terminal ether hydroxyl groups or double-terminal hydrocarbon hydroxyl groups, and has a molecular weight of 1000-3000 g / mol.

9. The method for preparing a copolyamide hot melt adhesive for bonding low surface energy fabrics according to claim 7, characterized in that: The diisocyanate is one of hexamethyl diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate and 4,4'-diphenylmethane diisocyanate.

10. The method for preparing a copolyamide hot melt adhesive for bonding low surface energy fabrics according to claim 7, characterized in that: The catalyst is an organic metal or an organic tertiary amine, wherein the organic metal includes dimethyl tin oxide, dipropyl tin oxide, dibutyl tin oxide, trihexyl tin oxide, dibutyl tin dilaurate, diphenol tin oxide, trinaphthyl tin oxide, butylphenyl tin oxide, dibutylpropyl tin oxide or tributyl tin oxide; the organic tertiary amine includes triethylamine, triethylenediamine or stannous octoate plus triethylenediamine; the added amount of the catalyst is 0.01%-0.03% of the total mass of the diisocyanate and the terminal hydroxyl silicone oil.

Images