A transparent copolyamide resin and a method for producing the same

Abstract

The application discloses a kind of transparent copolyamide resin and its preparation method, comprising: by containing triazole side group aromatic diacid and alicyclic diamine is prepared by salt reaction polyamide salt, again with caprolactam random copolymerization and preparation obtained target resin.The transparent copolyamide resin involved in the application has the characteristics of simple synthetic route, process environmental protection, product diversification, excellent heat resistance, high toughness and high light transmittance etc..

Description

Technical Field

[0001] This invention relates to the field of copolyamide resin technology, specifically to a transparent copolyamide resin and its preparation method. Background Technology

[0002] Polyamide, commonly known as nylon, is a general term for resins containing repeating amide groups -[NHCO]- in their molecular chains. It is the thermoplastic resin with the largest production volume, the most varieties, the widest application, and excellent comprehensive performance among the five major general-purpose engineering plastics. Ordinary polyamides such as PA6 and PA66 are mostly crystalline or semi-crystalline resins and are opaque. Transparent polyamides, on the other hand, are a new type of special resin, mostly amorphous polyamides or microcrystalline resins with crystal sizes smaller than the wavelength of visible light. Transparent polyamides have excellent mechanical properties, heat resistance, corrosion resistance, and wear resistance, and can be widely used in precision optical instruments, automobiles and electronic products, windows, transparent containers, etc.

[0003] Currently, there are two main types of transparent polyamides on the market: semi-aromatic transparent polyamides and alicyclic transparent polyamides. Semi-aromatic transparent polyamides have a wide range of raw material sources and good heat resistance. Alicyclic transparent polyamides have better overall mechanical and processing properties than semi-aromatic transparent polyamides, but their raw material prices are higher, which limits their application to some extent.

[0004] Chinese patent CN202211398042.6 discloses a bio-based copolymer transparent nylon. By introducing isosorbide, diamine, diacid monomers, and aromatic acids into the copolymer, a bio-based copolymer transparent nylon with excellent comprehensive properties is obtained. This patent introduces a chiral bio-based diol into the high-temperature resistant nylon backbone, disrupting the molecular chain regularity. The resulting bio-based transparent nylon exhibits superior optical properties, heat resistance, mechanical strength, and lower water absorption. However, the reaction process involved in this patent involves an amino-ester exchange reaction, leading to decreased controllability of the polymerization process. Chinese patent CN202210614129.6 discloses a transparent polyamide that can withstand anhydrous ethanol, belonging to microcrystalline or semi-crystalline transparent nylon, which is polymerized from the following components: adipic acid; hexamethylenediamine; a diamine containing cyclohexyl groups, selected from bis(4-amino-cyclohexyl)methane and bis(4-amino-3-methyl-cyclohexyl)methane; and a diacid monomer selected from terephthalic acid, isophthalic acid, and dodecanoic acid. The transparent polyamide prepared by this invention has excellent resistance to alcohol solvents, but its glass transition temperature is relatively low, making it unsuitable for use in demanding temperature-sensitive applications. Summary of the Invention

[0005] The purpose of this invention is to provide a transparent copolyamide resin and its preparation method to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A transparent copolyamide resin, wherein the transparent copolyamide has the following structure:

[0008]

[0009] The R1 structure is as follows:

[0010] The R2 structure is as follows:

[0011] The aromatic dicarboxylic acid containing the R1 structure is 5,5'-bis(1H-1,2,4-triazol-1-yl)-[1,1'-biphenyl]-3,3'-dicarboxylic acid.

[0012] The alicyclic diamine containing the R2 structure is one or more of 1,4-cyclohexanediamine, 5-amino-1,3,3-trimethylcyclohexanemethylamine, 4,4'-diaminodicyclohexylmethane, and 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane.

[0013] A method for preparing a transparent copolyamide mainly includes the following steps:

[0014] 1) A certain amount of 5,5'-bis(1H-1,2,4-triazol-1-yl)-[1,1'-biphenyl]-3,3'-dicarboxylic acid was reacted with an alicyclic diamine in pure water to form a salt, and the polyamide salt was obtained by filtration.

[0015] 2) Add a certain proportion of polyamide salt, caprolactam, catalyst and initiator into the reactor. After adding the materials, replace the air in the reactor with high-purity nitrogen 3 to 4 times. Raise the temperature to 200 to 220°C and maintain the pressure inside the reactor at 1.5 to 2.5 MPa. Continue to raise the temperature to 280 to 300°C and maintain the pressure inside the reactor at 1.5 to 2.0 MPa. After holding the pressure for 1.0 to 2.0 hours, release the gas to atmospheric pressure and drain the water from the system. Then gradually evacuate the system to reduce the pressure to -0.03 to -0.07 MPa. Discharge the material to obtain transparent copolyamide resin.

[0016] The polyamide salt is prepared by reacting 5,5'-bis(1H-1,2,4-triazol-1-yl)-[1,1'-biphenyl]-3,3'-dicarboxylic acid with an alicyclic diamine in pure water to form a salt, with a molar ratio of 0.98 to 1:1.

[0017] The mass ratio of the polyamide salt to caprolactam is 1:3 to 5.

[0018] The catalyst is one of phosphoric acid, phosphorous acid, and sodium hypophosphite, and the amount added is 0.1-0.5% of the total amount of polyamide salt and caprolactam.

[0019] The initiator is water, and the amount added is 2-5% of the mass of caprolactam.

[0020] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0021] 1. This invention involves the formation of a polyamide salt by a dicarboxylic acid with a large-volume side group structure and an alicyclic diamine, followed by random copolymerization with caprolactam to prepare a transparent copolyamide resin. The large-volume side group structure reduces the regularity of the transparent copolyamide resin molecular chain, significantly reduces crystallinity, and increases light transmittance. Furthermore, the introduction of alicyclic structures into the macromolecular backbone ensures that the polymer has a high glass transition temperature while synergistically improving its light transmittance. The combined effect of these two factors significantly enhances the light transmittance of the transparent copolyamide resin, making its light transmittance exceed 90%.

[0022] 2. The diacid with the large-volume side group structure of the present invention contains a triazole group. The lone pair electrons on its nitrogen atom easily generate intermolecular interaction forces with the carbonyl group, thereby exhibiting high toughness macroscopically and obtaining a copolyamide resin that has both transparency and high toughness.

[0023] 3. Because the present invention introduces a large amount of polyamide salt into the main chain of polyamide 6, the heat resistance temperature of the transparent copolyamide resin is 20-30°C higher than that of traditional transparent polyamide, which can be used in places with more stringent heat resistance requirements. It has a very wide range of application prospects in the automotive industry, electronics and electrical industry and optical display industry. Attached Figure Description

[0024] Figure 1 The infrared curve of the transparent copolyamide prepared in Example 4 of this invention; Detailed Implementation

[0025] To provide a more detailed understanding of the features and technical content of this invention, the implementation of this invention will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for reference only and are not intended to limit this invention.

[0026] Example 1

[0027] 10 mol (3763.3 g) of 5,5'-bis(1H-1,2,4-triazol-1-yl)-[1,1'-biphenyl]-3,3'-dicarboxylic acid was reacted with 10 mol (1141.9 g) of 1,4-cyclohexanediamine in pure water to form a salt, and the polyamide salt was obtained after filtration.

[0028] 3000g of polyamide salt, 5000g of caprolactam, 40g of sodium hypophosphite and 250g of deionized water were added to a reactor. After adding the materials, the air inside the reactor was replaced three times with high-purity nitrogen. The temperature was raised to 210℃, and the pressure inside the reactor was maintained at 1.8MPa. The temperature was then raised to 280℃, and the pressure inside the reactor was maintained at 2.0MPa. After holding the pressure for 1.5 hours, the gas was released to atmospheric pressure, and the water in the system was drained. Then, a vacuum was gradually drawn to reduce the pressure of the system to -0.07MPa. The transparent copolyamide resin was obtained by discharging the material.

[0029] Example 2

[0030] 10 mol (3763.3 g) of 5,5'-bis(1H-1,2,4-triazol-1-yl)-[1,1'-biphenyl]-3,3'-dicarboxylic acid and 10 mol (1702.9 g) of 5-amino-1,3,3-trimethylcyclohexanemethylamine were reacted in pure water to form a salt, and the polyamide salt was obtained after filtration.

[0031] 3000g of polyamide salt, 5000g of caprolactam, 40g of sodium hypophosphite and 250g of deionized water were added to a reactor. After adding the materials, the air inside the reactor was replaced three times with high-purity nitrogen. The temperature was raised to 210℃, and the pressure inside the reactor was maintained at 1.8MPa. The temperature was then raised to 280℃, and the pressure inside the reactor was maintained at 2.0MPa. After holding the pressure for 1.5 hours, the gas was released to atmospheric pressure, and the water in the system was drained. Then, a vacuum was gradually drawn to reduce the pressure of the system to -0.07MPa. The transparent copolyamide resin was obtained by discharging the material.

[0032] Example 3

[0033] 10 mol (3763.3 g) of 5,5'-bis(1H-1,2,4-triazol-1-yl)-[1,1'-biphenyl]-3,3'-dicarboxylic acid was reacted with 10 mol (2103.6 g) of 4,4'-diaminodicyclohexylmethane in pure water to form a salt, and the result was obtained by filtration and polyamide salt.

[0034] 3000g of polyamide salt, 5000g of caprolactam, 40g of sodium hypophosphite and 250g of deionized water were added to a reactor. After adding the materials, the air inside the reactor was replaced three times with high-purity nitrogen. The temperature was raised to 210℃, and the pressure inside the reactor was maintained at 1.8MPa. The temperature was then raised to 280℃, and the pressure inside the reactor was maintained at 2.0MPa. After holding the pressure for 1.5 hours, the gas was released to atmospheric pressure, and the water in the system was drained. Then, a vacuum was gradually drawn to reduce the pressure of the system to -0.07MPa. The transparent copolyamide resin was obtained by discharging the material.

[0035] Example 4

[0036] 10 mol (3763.3 g) of 5,5'-bis(1H-1,2,4-triazol-1-yl)-[1,1'-biphenyl]-3,3'-dicarboxylic acid was reacted with 10 mol (2384.1 g) of 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane in pure water to form a salt, and the polyamide salt was obtained after filtration.

[0037] 3000g of polyamide salt, 5000g of caprolactam, 40g of sodium hypophosphite and 250g of deionized water were added to a reactor. After adding the materials, the air inside the reactor was replaced three times with high-purity nitrogen. The temperature was raised to 210℃, and the pressure inside the reactor was maintained at 1.8MPa. The temperature was then raised to 280℃, and the pressure inside the reactor was maintained at 2.0MPa. After holding the pressure for 1.5 hours, the gas was released to atmospheric pressure, and the water in the system was drained. Then, a vacuum was gradually drawn to reduce the pressure of the system to -0.07MPa. The transparent copolyamide resin was obtained by discharging the material.

[0038] Example 5

[0039] 10 mol (3763.3 g) of 5,5'-bis(1H-1,2,4-triazol-1-yl)-[1,1'-biphenyl]-3,3'-dicarboxylic acid was reacted with 10 mol (2384.1 g) of 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane in pure water to form a salt, and the polyamide salt was obtained after filtration.

[0040] 2500g of polyamide salt, 5000g of caprolactam, 35g of sodium hypophosphite and 200g of deionized water were added to a reactor. After adding the materials, the air inside the reactor was replaced three times with high-purity nitrogen. The temperature was raised to 210℃, and the pressure inside the reactor was maintained at 1.8MPa. The temperature was then raised to 280℃, and the pressure inside the reactor was maintained at 2.0MPa. After holding the pressure for 1.5 hours, the gas was released to atmospheric pressure, and the water in the system was drained. Then, a vacuum was gradually drawn to reduce the pressure of the system to -0.07MPa. The transparent copolyamide resin was obtained by discharging the material.

[0041] Example 6

[0042] 10 mol (3763.3 g) of 5,5'-bis(1H-1,2,4-triazol-1-yl)-[1,1'-biphenyl]-3,3'-dicarboxylic acid was reacted with 10 mol (2384.1 g) of 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane in pure water to form a salt, and the polyamide salt was obtained after filtration.

[0043] 2000g of polyamide salt, 5000g of caprolactam, 30g of sodium hypophosphite and 200g of deionized water were added to a reactor. After adding the materials, the air inside the reactor was replaced three times with high-purity nitrogen. The temperature was raised to 210℃, and the pressure inside the reactor was maintained at 1.8MPa. The temperature was then raised to 280℃, and the pressure inside the reactor was maintained at 2.0MPa. After holding the pressure for 1.5 hours, the gas was released to atmospheric pressure, and the water in the system was drained. Then, a vacuum was gradually drawn to reduce the pressure of the system to -0.07MPa. The transparent copolyamide resin was obtained by discharging the material.

[0044] Comparative Example 1

[0045] Terephthalic acid and hexamethylenediamine were reacted in water to form a salt, yielding 6T salt; isophthalic acid and hexamethylenediamine were reacted in water to form a salt, yielding 6I salt; 7000g of 6T salt and 3000g of 6I salt were added to a reaction vessel at a mass ratio of 70:30, along with 50g of sodium hypophosphite and 500g of deionized water. The air inside the reaction vessel was replaced three times with high-purity nitrogen. The temperature was raised to 210℃, and the pressure inside the vessel was maintained at 1.9MPa. The temperature was then raised to 295℃, and the pressure inside the vessel was maintained at 2.0MPa. After holding the pressure for 1.5 hours, the gas was released to atmospheric pressure, and the water in the system was drained. Then, a vacuum was gradually drawn to reduce the pressure of the system to -0.07MPa. The transparent 6T / 6I copolyamide was obtained by discharging the material.

[0046]

[0047] Table 1. Performance data of transparent copolyamides prepared in each example and comparative examples.

[0048] As shown in Table 1, compared with the transparent 6T / 6I copolyamide, the transparent copolyamide involved in this patent has more obvious advantages in terms of heat resistance, toughness, and light transmittance. Its glass transition temperature is above 160℃, which can be used in more demanding temperature conditions. Its elongation at break and notched impact strength are higher, and its toughness is significantly improved. Its light transmittance is over 90%, with a maximum of 92.3%, which can meet the high light transmittance requirements of some specific applications.

[0049] Depend on Figure 1 It can be seen that each of its characteristic peaks corresponds one-to-one with the molecular structure of the transparent copolyamide obtained in Example 4, proving that the obtained copolymer is consistent with the experimental design.

[0050] The aromatic dicarboxylic acid containing a triazole side group is from Zhengzhou Alpha Chemical Co., Ltd., the 1,4-cyclohexanediamine is from Hubei Shishun Biotechnology Co., Ltd., the 5-amino-1,3,3-trimethylcyclohexanemethylamine is from Wuhan Kanos Technology Co., Ltd., and the 4,4'-diaminodicyclohexylmethane and 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane are from Hubei Keward Chemical Co., Ltd.

[0051] 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 alterations 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 transparent copolyamide resin, characterized in that... The transparent copolyamide has the following structure: ； The structure of R1 is as follows: The R2 structure is as follows: , , , .

2. The transparent copolyamide resin according to claim 1, characterized in that: The aromatic dicarboxylic acid containing the R1 structure is 5,5'-bis(1H-1,2,4-triazol-1-yl)-[1,1'-biphenyl]-3,3'-dicarboxylic acid.

3. The transparent copolyamide resin according to claim 1, characterized in that: The alicyclic diamine containing the R2 structure is one or more of 1,4-cyclohexanediamine, 5-amino-1,3,3-trimethylcyclohexanemethylamine, 4,4'-diaminodicyclohexylmethane, and 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane.

4. The method for preparing a transparent copolyamide according to claim 1, characterized in that: The main steps include the following: 1) A certain amount of 5,5'-bis(1H-1,2,4-triazol-1-yl)-[1,1'-biphenyl]-3,3'-dicarboxylic acid was reacted with an alicyclic diamine in pure water to form a salt, and the polyamide salt was obtained by filtration. 2) Add a certain proportion of polyamide salt, caprolactam, catalyst and initiator into the reactor. After adding the materials, replace the air in the reactor with high-purity nitrogen 3 to 4 times. Raise the temperature to 200 to 220°C and maintain the pressure inside the reactor at 1.5 to 2.5 MPa. Continue to raise the temperature to 280 to 300°C and maintain the pressure inside the reactor at 1.5 to 2.0 MPa. After holding the pressure for 1.0 to 2.0 hours, release the gas to atmospheric pressure and drain the water from the system. Then gradually evacuate the system to reduce the pressure to -0.03 to -0.07 MPa. Discharge the material to obtain transparent copolyamide resin.

5. The method for preparing a transparent copolyamide according to claim 4, characterized in that: The molar ratio of the 5,5'-bis(1H-1,2,4-triazol-1-yl)-[1,1'-biphenyl]-3,3'-dicarboxylic acid to the alicyclic diamine is 0.98~1:

1.

6. The method for preparing a transparent copolyamide according to claim 4, characterized in that: The mass ratio of the polyamide salt to caprolactam is 1:3~5.

7. The method for preparing a transparent copolyamide according to claim 4, characterized in that: The catalyst is one of phosphoric acid, phosphorous acid, or sodium hypophosphite, and the amount added is 0.1-0.5% of the total amount of polyamide salt and caprolactam.

8. The method for preparing a transparent copolyamide according to claim 4, characterized in that: The initiator is water, and the amount added is 2-5% of the mass of caprolactam.

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