A polyamide resin, a method for preparing the same, and an application thereof

Abstract

This invention belongs to the field of polyamide resin technology, and particularly relates to a polyamide resin, its preparation method, and its application. The polyamide resin comprises the following raw materials: a) carboxylic acid compounds; b) polyamine compounds; c) compounds with the structure shown in formula (I); in formula (I), R is selected from H or hydroxyl groups. The polyamide resin obtained by this invention not only has good alcohol solubility and water resistance, but also high heat resistance and good adhesion to substrates.

Description

Technical Field

[0001] This invention belongs to the field of polyamide resin technology, and particularly relates to a polyamide resin, its preparation method and application. Background Technology

[0002] Polyamide resins are mainly formed by the condensation of diacids and diamines. Their molecular structure contains a high density of amide bonds, which endows the material with good adhesion to metals and plastics, excellent thermal stability, and good resistance to chemical reagents. Polyamide inks are mainly used in gravure and letterpress printing, and are also indispensable inks for printing on packaging materials such as cellophane, polyethylene, and polypropylene films. Polyamide hot melt adhesives are also very important adhesives in the textile and footwear industries.

[0003] With increasingly stringent environmental protection requirements, alcohol-soluble polyamide resins, with their advantages of low toxicity, environmental friendliness, and high cost-effectiveness, are gradually replacing the more toxic benzene-soluble polyamide resins. However, currently prepared alcohol-soluble polyamide resins have poor properties in terms of hardness, water resistance, adhesion to substrates, hygroscopicity, and heat resistance, making it difficult to meet the application requirements under medium and high temperature conditions. In particular, during the high temperature and humidity of summer, polyamide resin adhesion problems are more likely to occur.

[0004] In response, improvements have been made in this field. For example, patent document CN103554486A prepared an alcohol-soluble dimer acid type polyamide resin by using ethanolamine modifiers. However, ethanolamine is a small molecule aliphatic amine with strong hygroscopicity, which leads to poor water resistance and heat resistance of the polyamide resin.

[0005] Therefore, in the research on the modification of polyamide resins, how to ensure that the polyamide resin has good alcohol solubility while also having strong water resistance, heat resistance and high adhesion is a technical challenge. Summary of the Invention

[0006] To address the above technical problems, this invention provides a polyamide resin, its preparation method, and its application. The resulting polyamide resin not only has good alcohol solubility but also good water resistance and high heat resistance, and has good adhesion to substrates.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] In a first aspect, a polyamide resin is provided, comprising the following raw materials:

[0009] a) Carboxylic acid compounds;

[0010] b) Polyamine compounds;

[0011] c) Compounds with the structure shown in formula (I):

[0012]

[0013] In formula (I), R is selected from H or hydroxyl.

[0014] According to the polyamide resin provided by the present invention, in some embodiments, the molar amount of carboxyl groups contained in component a) is in the ratio of the molar amount of primary amino groups contained in components b) and c) to 1:(0.8 to 1.2), for example 1:0.85, 1:0.9, 1:1, 1:1.05, 1:1.1, 1:1.15.

[0015] In some embodiments, the molar ratio of the carboxyl group contained in component a) to the molar ratio of the primary amino group contained in components b) and c) is 1:(0.9 to 1.1), preferably 1:(0.95 to 1.05).

[0016] In some embodiments, the molar ratio of component b) to component c) is 1:(0.05 to 0.25), for example, 1:0.055, 1:0.06, 1:0.08, 1:0.1, 1:0.15, 1:0.2, 1:0.21, 1:0.22, 1:0.24, preferably 1:(0.05 to 0.2).

[0017] In some embodiments of the polyamide resin provided by the present invention, the carboxylic acid compound is selected from one or more of dimer acid, trimer acid, oleic acid, methyl oleate, adipic acid, sebacic acid, succinic acid, and propionic acid.

[0018] In some embodiments, the polyamine compound is selected from one or more of ethylenediamine, hexamethylenediamine, decanediamine, pentanediamine, methylpentanediamine, isophoronediamine, 1,3-cyclohexanedimethylamine, 4,4'-diaminodicyclohexylmethane, and polyetheramines.

[0019] In a second aspect, a method for preparing the polyamide resin as described above is provided, comprising the following steps:

[0020] 1) Add components a), b), and c) to the reaction vessel, and under the protection of an inert gas (such as nitrogen), heat the system to 100–140°C (e.g., 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C), and carry out the reaction at this temperature (e.g., stir the mixture thoroughly before reacting).

[0021] 2) Under stirring and inert gas (such as nitrogen) protection, heat the system to 140-180℃ (e.g., 145℃, 150℃, 155℃, 160℃, 165℃, 170℃, 175℃) and maintain the temperature at this temperature for the reaction.

[0022] 3) Under stirring and inert gas (such as nitrogen) protection, heat the system to 180-220℃ (e.g., 185℃, 190℃, 195℃, 200℃, 205℃, 210℃, 215℃) and maintain the temperature at this temperature for the reaction.

[0023] 4) Under stirring and inert gas (such as nitrogen) protection, heat the system to 220-270℃ (e.g., 225℃, 230℃, 235℃, 240℃, 245℃, 250℃, 255℃, 260℃, 265℃) and maintain the reaction at this temperature.

[0024] 5) After removing water and unreacted small molecules from the system under vacuum, the mixture is cooled and discharged to obtain polyamide resin.

[0025] According to the preparation method provided by the present invention, in some embodiments, the reaction time in step 1) is 0.5 to 2 hours, for example, 1 hour, 1.5 hours, or 1.8 hours.

[0026] In some implementation schemes, the reaction time in step 2) is 1 to 3 hours, for example, 1.5 hours, 2 hours, or 2.5 hours.

[0027] In some implementation schemes, the reaction time in step 3) is 1 to 3 hours, for example, 1.5 hours, 2 hours, or 2.5 hours.

[0028] In some implementation schemes, the reaction time in step 4) is 1 to 3 hours, for example, 1.5 hours, 2 hours, or 2.5 hours.

[0029] In a third aspect, the application of the polyamide resin as described above or the polyamide resin prepared by the preparation method as described above in inks and hot melt adhesives is provided.

[0030] In this article, the application steps or processes of polyamide resin in inks and hot melt adhesives can be conventional operations in the field, and will not be described in detail here.

[0031] Compared with the prior art, the beneficial effects of the technical solution of the present invention are at least as follows:

[0032] Compared with existing systems, this invention introduces a polycyclic amine compound into polyamide resin. This polycyclic cyclic structure has strong hydrophobic properties, which can improve the heat resistance and water resistance of polyamide resin while maintaining considerable alcohol solubility, and will not exhibit significant moisture absorption under high humidity conditions. At the same time, it can also improve the hardness and adhesion of polyamide resin to a certain extent, thereby improving the mechanical strength of polyamide resin.

[0033] In the system of amine compounds with multi-cyclic structures introduced in this invention, the introduction of amine compounds with multi-cyclic structures containing hydroxyl groups into polyamide resin further improves alcohol solubility while maintaining considerable hardness, water and heat resistance, and adhesion to various substrates.

[0034] The polycyclic cyclic compounds introduced into the polyamide resin of the present invention can be used in combination with various diamines to prepare polyamide resins with different structures and properties, meeting the application needs of various occasions. Detailed Implementation

[0035] To provide a detailed understanding of the technical features and content of this invention, preferred embodiments will be described in more detail below. While preferred embodiments are described in the examples, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply.

[0036] The names, abbreviations, and sources of the main chemicals used in the various embodiments of this invention are shown in Table 1 below. Unless otherwise specified, all reagents used are of analytical grade.

[0037] Table 1 Information on Main Raw Materials

[0038] Chemical Name source ethylenediamine, hexamethylenediamine Inokai dimer acid, oleic acid Shandong Huijin Isophorone diamine Wanhua Chemical 4,4'-Diaminodicyclohexylmethane Wanhua Chemical 4-(cyclohexylmethyl)cyclohexylamine; that is, R in formula (I) is H Wanhua Chemical 4-[(4-aminocyclohexyl)methyl]cyclohexanol; that is, R in formula (I) is -OH Wanhua Chemical

[0039] The main testing methods used in this invention are as follows:

[0040] (1) Hardness: The Shore D hardness of the polyamide resin sample to be tested was tested using a hardness tester;

[0041] (2) Softening point: The softening point of the polyamide resin sample to be tested was determined in accordance with GB / T 1633-2017 "Determination of Softening Point of Resin by Ring and Ball Method".

[0042] (3) Mechanical properties (peel strength): The polyamide resin to be tested is hot melted and coated onto both sides of a clean iron sheet with a size of 20mm*100mm. Then, a canvas of the same size is pressed tightly onto the iron sheet. After curing, the tensile strength test is used to test the force that the canvas can be pulled apart.

[0043] (4) Water resistance test: Prepare the sample to be tested according to the method in point (3) above, then soak it in water for 24 hours, and then perform mechanical property test according to the description in point (3) above;

[0044] (5) Alcohol solubility test: Dissolve the polyamide resin to be tested in ethanol and test the viscosity of the polyamide resin ethanol solution at 50% solid content; the lower the viscosity, the better its alcohol solubility.

[0045]

Example 1

[0046] The preparation method of polyamide resin is as follows:

[0047] 1) Add 1000g of dimer acid (1.78mol), 50g of ethylenediamine (0.83mol), 100g of hexamethylenediamine (0.86mol), and 40g of 4-(cyclohexylmethyl)cyclohexylamine (0.2mol) to a reaction vessel. Under nitrogen protection, heat the system to 100℃ and stir the reaction at this temperature for 0.5h.

[0048] 2) Then, under stirring and nitrogen protection, the system was slowly heated to 140°C and kept at this temperature for 1 hour.

[0049] 3) Then, under stirring and nitrogen protection, the system was slowly heated to 180°C and kept at this temperature for 1 hour.

[0050] 4) Then, under stirring and nitrogen protection, the system was slowly heated to 220°C and kept at this temperature for 2 hours.

[0051] 5) Afterwards, water and unreacted small molecules in the system are removed by vacuum, the system is cooled and discharged to obtain polyamide resin ①.

[0052]

Example 2

[0053] The preparation method of polyamide resin is as follows:

[0054] 1) Add 1000g of dimer acid (1.78mol), 50g of ethylenediamine (0.83mol), 185g of 4,4'-diaminodicyclohexylmethane (0.88mol), and 16.5g of 4-(cyclohexylmethyl)cyclohexylamine (0.09mol) to a reaction vessel. Under nitrogen protection, heat the system to 120℃ and stir the reaction at this temperature for 1h.

[0055] 2) Then, under stirring and nitrogen protection, the system was slowly heated to 160°C and kept at this temperature for 2 hours.

[0056] 3) Then, under stirring and nitrogen protection, the system was slowly heated to 200°C and kept at this temperature for 1 hour.

[0057] 4) Then, under stirring and nitrogen protection, the system was slowly heated to 250°C and kept at this temperature for 3 hours.

[0058] 5) After that, water and unreacted small molecules in the system are removed by vacuum, the system is cooled and discharged to obtain polyamide resin ②.

[0059]

Example 3

[0060] The preparation method of the polyamide resin is the same as in Example 1, except that 4-(cyclohexylmethyl)cyclohexylamine in step 1) is replaced with 4-[(4-aminocyclohexyl)methyl]cyclohexanol; the remaining steps are the same as in Example 1. Polyamide resin ③ is obtained.

[0061]

Example 4

[0062] The preparation method of the polyamide resin is the same as in Example 2, except that 4-(cyclohexylmethyl)cyclohexylamine in step 1) is replaced with 4-[(4-aminocyclohexyl)methyl]cyclohexanol; the remaining steps are the same as in Example 1. Polyamide resin ④ is obtained.

[0063]

Example 5

[0064] The preparation method of polyamide resin is as follows:

[0065] 1) Add 800g of dimer acid (1.43mol), 200g of oleic acid (0.7mol), 50g of ethylenediamine (0.83mol), 160g of 4,4'-diaminodicyclohexylmethane (0.76mol), and 66g of 4-[(4-aminocyclohexyl)methyl]cyclohexanol (0.3mol) to a reaction vessel. Under nitrogen protection, heat the system to 120℃ and stir the reaction at this temperature for 1h.

[0066] 2) Then, under stirring and nitrogen protection, the system was slowly heated to 180°C and kept at this temperature for 2 hours.

[0067] 3) Then, under stirring and nitrogen protection, the system was slowly heated to 220°C and kept at this temperature for 1 hour.

[0068] 4) Then, under stirring and nitrogen protection, the system was slowly heated to 270°C and kept at this temperature for 2 hours.

[0069] 5) After that, water and unreacted small molecules in the system are removed by vacuum, the system is cooled and discharged to obtain polyamide resin ⑤.

[0070]

Example 6

[0071] The preparation method of polyamide resin is as follows:

[0072] 1) Add 800g of dimer acid (1.43mol), 200g of oleic acid (0.7mol), 100g of hexamethylenediamine (0.86mol), 150g of isophoronediamine (0.88mol), and 76g of 4-[(4-aminocyclohexyl)methyl]cyclohexanol (0.36mol) to a reaction vessel. Under nitrogen protection, heat the system to 120℃ and stir the reaction at this temperature for 1h.

[0073] 2) Then, under stirring and nitrogen protection, the system was slowly heated to 180°C and kept at this temperature for 2 hours.

[0074] 3) Then, under stirring and nitrogen protection, the system was slowly heated to 220°C and kept at this temperature for 2 hours.

[0075] 4) Then, under stirring and nitrogen protection, the system was slowly heated to 250°C and kept at this temperature for 2 hours.

[0076] 5) After that, water and unreacted small molecules in the system are removed by vacuum, the system is cooled and discharged to obtain polyamide resin ⑥.

[0077] [Comparative Example 1] - Compared with Example 5

[0078] The preparation method of polyamide resin is as follows:

[0079] 1) Add 800g of dimer acid (1.43mol), 200g of oleic acid (0.7mol), 50g of ethylenediamine (0.83mol), 160g of 4,4'-diaminodicyclohexylmethane (0.76mol), and 18.3g of ethanolamine (0.3mol) to a reaction vessel. Under nitrogen protection, heat the system to 120℃ and stir the reaction at this temperature for 1h.

[0080] 2) Then, under stirring and nitrogen protection, the system was slowly heated to 180°C and kept at this temperature for 2 hours.

[0081] 3) Then, under stirring and nitrogen protection, the system was slowly heated to 220°C and kept at this temperature for 1 hour.

[0082] 4) Then, under stirring and nitrogen protection, the system was slowly heated to 270°C and kept at this temperature for 2 hours.

[0083] 5) After that, water and unreacted small molecules in the system are removed by vacuum, the system is cooled and discharged to obtain polyamide resin ⑦.

[0084] Comparative Example 2

[0085] The preparation method of polyamide resin is the same as in Example 1, except that the amount of 4-(cyclohexylmethyl)cyclohexylamine is replaced with 3.9g (0.02mol); the remaining steps are the same as in Example 1; and polyamide resin ⑧ is obtained.

[0086] Comparative Example 3

[0087] The preparation method of polyamide resin is the same as in Example 1, except that the amount of 4-(cyclohexylmethyl)cyclohexylamine is replaced with 58.2 g (0.3 mol); the remaining steps are the same as in Example 1; and polyamide resin ⑨ is obtained.

[0088] The performance of the polyamide resins prepared in each embodiment and comparative example was tested, and the results are shown in Table 2:

[0089] Table 2. Performance test results of polyamide resin

[0090]

[0091] The test results above show that, under the condition of comparable alcohol solubility, the polyamide resin in the embodiments of the present invention has higher heat resistance and higher hardness, and at the same time has better adhesion and bonding performance on the substrate surface, thus giving it excellent mechanical properties; that is, it can achieve a balance between the alcohol solubility, hardness, heat resistance, water resistance and bonding performance of the obtained polyamide resin, and has high practical value.

[0092] Compared with Examples 1-2, Examples 3-4 introduce amine compounds with hydroxyl-containing polycyclic cyclic structures into polyamide resins. While maintaining comparable properties such as hardness, water resistance, heat resistance, and adhesion of the polyamide resins, they have certain advantages in alcohol solubility.

[0093] Compared to Comparative Example 1, which did not introduce a polycyclic amine compound, Example 5 introduced a polycyclic amine compound into the polyamide resin, which improved the hardness, water resistance, heat resistance, and adhesion of the polyamide resin to a variety of substrates while maintaining comparable alcohol solubility.

[0094] In Comparative Examples 2-3, although polycyclic amine compounds were also added, their dosage was not controlled within a suitable range, making it impossible to achieve a balance between the alcohol solubility, hardness, heat resistance, water resistance, and adhesion of the resulting polyamide resin.

[0095] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the spirit of the invention.

Claims

1. A polyamide resin, characterized in that, It includes the following raw material components: a) Carboxylic acid compounds; b) Polyamine compounds; c) Compounds with the structure shown in formula (I): , formula (I) In formula (I), R is selected from H or hydroxyl; The polyamide resin is prepared by the following method: 1) Add components a), b), and c) to the reaction vessel, heat the system to 100~140℃ under inert gas protection, and carry out the reaction at this temperature; 2) Under stirring and inert gas protection, heat the system to 140~180℃ and maintain the temperature at this temperature for the reaction; 3) Under stirring and inert gas protection, heat the system to 180~220℃ and maintain the temperature at this temperature for the reaction; 4) Under stirring and inert gas protection, heat the system to 220~270℃ and maintain the temperature at this temperature for the reaction; 5) After removing water and unreacted small molecules from the system under vacuum, the mixture is cooled and discharged to obtain polyamide resin.

2. The polyamide resin according to claim 1, characterized in that, The molar ratio of the carboxyl group in component a) to the molar ratio of the primary amino group in components b) and c) is 1:(0.8~1.2).

3. The polyamide resin according to claim 1, characterized in that, The molar ratio of the carboxyl group in component a) to the molar ratio of the primary amino group in components b) and c) is 1:(0.9~1.1).

4. The polyamide resin according to claim 3, characterized in that, The molar ratio of the carboxyl group in component a) to the molar ratio of the primary amino group in components b) and c) is 1:(0.95~1.05).

5. The polyamide resin according to any one of claims 1-4, characterized in that, The molar ratio of component b) to component c) is 1:(0.05~0.25).

6. The polyamide resin according to claim 5, characterized in that, The molar ratio of component b) to component c) is 1:(0.05~0.2).

7. The polyamide resin according to any one of claims 1-4 and 6, characterized in that, The carboxylic acid compounds are selected from one or more of dimer acids, trimer acids, oleic acid, methyl oleate, adipic acid, sebacic acid, and succinic acid.

8. The polyamide resin according to any one of claims 1-4 and 6, characterized in that, The polyamine compound is selected from one or more of ethylenediamine, hexamethylenediamine, decanediamine, pentanediamine, methylpentanediamine, isophoronediamine, 1,3-cyclohexanedimethylamine, 4,4'-diaminodicyclohexylmethane, and polyetheramines.

9. The method for preparing the polyamide resin according to any one of claims 1-8, characterized in that, Includes the following steps: 1) Add components a), b), and c) to the reaction vessel, heat the system to 100~140℃ under inert gas protection, and carry out the reaction at this temperature; 2) Under stirring and inert gas protection, heat the system to 140~180℃ and maintain the temperature at this temperature for the reaction; 3) Under stirring and inert gas protection, heat the system to 180~220℃ and maintain the temperature at this temperature for the reaction; 4) Under stirring and inert gas protection, heat the system to 220~270℃ and maintain the temperature at this temperature for the reaction; 5) After removing water and unreacted small molecules from the system under vacuum, the mixture is cooled and discharged to obtain polyamide resin.

10. The preparation method according to claim 9, characterized in that, The reaction time in step 1) is 0.5~2h.

11. The preparation method according to claim 9 or 10, characterized in that, The reaction time in step 2) is 1-3 hours; The reaction time in step 3) is 1-3 hours; The reaction time in step 4) is 1~3 hours.

12. The application of the polyamide resin according to any one of claims 1-8 or the polyamide resin prepared by the preparation method according to any one of claims 9-11 in inks and hot melt adhesives.

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