Toughened transparent long-carbon-chain polyamide and preparation method thereof

Abstract

The invention belongs to the technical field of macromolecules, and particularly relates to toughened transparent long-carbon-chain polyamide and a preparation method thereof. The toughened transparent long-carbon-chain polyamide is formed by copolymerization of an L1 chain segment oligomer and an L2 chain segment oligomer, the structural formula is # imgabs0, the end groups of the two ends of the L1 chain segment oligomer are amino groups, the L1 chain segment oligomer is formed by 45-50 mol% of aliphatic diacid and 50-55 mol% of aliphatic diamine, the number of carbon atoms of the aliphatic diacid is larger than or equal to 10, and the number of carbon atoms of the aliphatic diamine is larger than or equal to 6; the end groups at the two ends of the L2 chain segment oligomer are carboxyl groups, and the L2 chain segment oligomer is formed by the following substances: 30-50 mol% of alkyl-substituted bis (aminocyclohexyl) methane and 50-70 mol% of carboxyl-terminated polyether. The high-toughness transparent plastic has good toughness and transparency, and can be used in the fields with high toughness and transparency requirements, such as precision optical instruments, pressure-resistant windows, observation mirrors, special lamp outer covers, food packaging films, high-grade sports equipment and the like.

Description

Technical Field

[0001] The invention relates to the technical field of polymers, and in particular to a toughened transparent long carbon chain polyamide and a preparation method thereof. Background Art

[0002] Polyamide, commonly known as nylon, is a type of polymer compound that characteristically contains amide groups in its main molecular chain. It is easy to form hydrogen bonds between its molecules and has the characteristics of high strength, high toughness, good wear resistance and easy processing. Long carbon chain polyamide is a type of polyamide with more than 10 methylene groups between adjacent amide groups. The longer methylene chain and polar amide group make it have the dual characteristics of polyolefin and polyamide. The flexible methylene chain limited by the long carbon chain makes it have unique advantages such as good toughness, low water absorption, good dimensional stability, low temperature impact resistance and dielectric properties. It has important applications in the fields of automobiles, electronic appliances, aerospace, oil and alcohol transportation. With the expansion of the application range of long carbon chain polyamide, higher requirements are put forward for the performance of long carbon chain polyamide, such as higher flexibility for application in automotive system pipelines, petrochemical pipelines, hydraulic transmission system pipelines and other fields, and higher transparency for application in precision optical instruments, pressure-resistant windows, observation mirrors, special lamp covers, food packaging films, high-end sports equipment and other fields. Therefore, it is necessary to further develop long carbon chain polyamide with high toughness and good transparency.

[0003] Invention patent CN105949762B discloses a toughened transparent nylon and a preparation method thereof. The raw materials include transparent nylon resin, a toughening agent, an antioxidant, a lubricant, and a light stabilizer. All the raw materials are mixed in a high-speed mixer and then added to a twin-screw extruder for traction cooling and extrusion granulation. The invention improves the toughness of transparent nylon by adding a toughening agent. The process is simple, but the transparency problem of toughened transparent nylon is not described.

[0004] Invention patent CN118580488A discloses a high-toughness copolymer transparent polyamide and a preparation method thereof, which is prepared by copolymerization of polymer monomers of alicyclic diamine, aliphatic dicarboxylic acid, aliphatic diamine with a side group structure and aliphatic dibasic acid with a side group structure under the action of a catalyst. The random copolymerization of multiple components may lead to a decrease in tensile strength and thermal stability. Summary of the invention

[0005] In view of the above technical problems and the shortcomings in the art, the present invention provides a toughened transparent long carbon chain polyamide and a preparation method thereof. The toughened transparent long carbon chain polyamide prepared by the present invention has good toughness and transparency, and can be used in fields with high requirements for toughness and transparency, such as precision optical instruments, pressure-resistant windows, observation mirrors, special lamp covers, food packaging films, and high-end sports equipment.

[0006] In order to achieve the above technical objectives, the technical solution adopted by the embodiment of the present invention is: In the first aspect, the embodiment of the present invention provides a toughened transparent long carbon chain polyamide, which is copolymerized by L1 segment oligomer and L2 segment oligomer, and has the structural formula: The terminal groups at both ends of the L1 segment oligomer are amine groups, which are formed by: 45-50 mol% of an aliphatic diacid and 50-55 mol% of an aliphatic diamine, wherein the carbon number of the aliphatic diacid is greater than or equal to 10, and the carbon number of the aliphatic diamine is greater than or equal to 6; The terminal groups at both ends of the L2 segment oligomer are carboxyl groups, which are formed by: 30-50 mol % of alkyl-substituted bis(aminocyclohexyl)methane and 50-70 mol % of carboxyl-terminated polyether.

[0007] Furthermore, the aliphatic diacid includes one or more of sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedicarboxylic acid, hexadecanedioic acid, heptadecanedioic acid and octadecanedicarboxylic acid.

[0008] Furthermore, the aliphatic diamine includes one or more of hexamethylenediamine, decamethylenediamine, undecanediamine, dodecamethylenediamine, tridecanediamine, tetradecanediamine, pentadecanediamine, hexadecamethylenediamine, heptadecamethylenediamine and octadecanediamine.

[0009] Furthermore, the alkyl-substituted bis(aminocyclohexyl)methane is 4,4'-diaminodicyclohexylmethane PACM or 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane MACM.

[0010] Furthermore, the carboxyl-terminated polyether is polytetrahydrofuran ether diacid with a number average molecular weight of 600-2000 or polyoxypropylene ether diacid with a number average molecular weight of 600-2000.

[0011] Furthermore, the amount of the L2 segment oligomer is 15-30% by weight, and the amount of the L1 segment oligomer is 70-85% by weight.

[0012] In a second aspect, an embodiment of the present invention provides a method for preparing the toughened transparent long carbon chain polyamide according to the first aspect, comprising the following steps: (1) Add 100 parts of aliphatic diacid, 40-100 parts of aliphatic diamine and 150-300 parts of deionized water into a reaction kettle by weight, start stirring, heat to 180-220° C., react at a pressure of 0.8-2.0 MPa for 2-8 hours; reduce the pressure to normal pressure after 2-5 hours, and raise the system temperature to 220-250° C., then evacuate the reaction kettle, reduce the pressure of the reaction kettle to an absolute pressure of 1000-2000 Pa, and react for 1-2 hours to obtain L1 segment oligomer; (2) Add 100 parts by weight of alkyl-substituted bis(aminocyclohexyl)methane, 400-1000 parts of carboxyl-terminated polyether and 500-1500 parts of deionized water into a reaction kettle, start stirring, heat to 180-220°C, react at a pressure of 0.8-2.0 MPa for 2-8 hours; reduce the pressure to normal pressure after 2-5 hours, and raise the system temperature to 220-250°C, then evacuate the reaction kettle, reduce the pressure of the reaction kettle to 500-1000 Pa absolute pressure, and react for 1-2 hours to obtain L2 segment oligomer; (3) Add L1 segment oligomer and L2 segment oligomer into a reactor, start stirring, heat to 220-250°C, and reduce the pressure of the reactor to an absolute pressure of 500-1000 Pa. React for 3-5 hours, and obtain toughened transparent long carbon chain polyamide through extrusion, cooling, granulation, drying and packaging.

[0013] Compared with the prior art, the technical solution provided by the embodiment of the present invention has the following beneficial effects: The present invention adopts carboxyl-terminated polyether and copolymerizes and modifies long-chain polyamide by copolymerization, so as to improve the toughness of long-chain polyamide. At the same time, due to the introduction of polyether, the regularity of polyamide chain segments is destroyed, the crystallization ability is weakened, and the transparency of long-chain polyamide can be improved. In order to further improve the transparency, the present invention finds that the long-chain polyamide can be copolymerized and modified by using the chain segments obtained by copolymerization of alicyclic diamine and carboxyl-terminated polyether, so as to further improve the transparency of long-chain polyamide. The obtained modified long-chain polyamide with high transparency and high toughness can be used in the fields of precision optical instruments, pressure-resistant windows, observation mirrors, special lamp covers, food packaging films, high-end sports equipment, etc. DETAILED DESCRIPTION

[0014] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0015] Example 1 A method for preparing a toughened transparent long carbon chain polyamide comprises the following steps: (1) Preparation of L1 segment oligomer: 46.1 kg of dodecanedioic acid, 35.3 kg of decanediamine and 80 kg of deionized water were added to the first reactor, stirred, heated to 190°C, and reacted at a pressure of 1.3 MPa for 4 hours; the pressure was reduced to normal pressure in 3 hours, and the system temperature was raised to 240°C, and then the reactor was evacuated to reduce the pressure to 1000 Pa (absolute pressure), and reacted for 2 hours to obtain PA1012 oligomer; (2) Preparation of L2 segment oligomer: 2.1 kg of 4,4'-diaminodicyclohexylmethane (PACM), 17.1 kg of polytetrahydrofuran ether diacid (number average molecular weight 1140) and 25 kg of deionized water were added to the second reactor, stirring was started, and the temperature was raised to 185°C. The reaction was carried out at a pressure of 1.2 MPa for 3 hours. The pressure was reduced to normal pressure within 3 hours, and the system temperature was raised to 230°C. Then, the reactor was evacuated and the pressure was reduced to 500 Pa (absolute pressure). The reaction was carried out for 2 hours to obtain a polyether oligomer. (3) Preparation of long-chain polyamide: The PA1012 oligomer obtained in step (1) and the polyether oligomer obtained in step (2) were placed in a third reactor, stirred, heated to 240°C, and the pressure of the reactor was reduced to 500 Pa (absolute pressure). The reaction was carried out for 3 hours. After extrusion, cooling, granulation, drying and packaging, a toughened transparent long-chain polyamide 1012 was obtained with a melt index of 10.6 g / 10 min (230°C, 2.16 kg).

[0016] Example 2 A method for preparing a toughened transparent long carbon chain polyamide comprises the following steps: (1) Preparation of L1 segment oligomer: 44.4 kg of sebacic acid, 38.9 kg of decanediamine and 90 kg of deionized water were added to the first reactor, stirred, heated to 200°C, and reacted at a pressure of 1.5 MPa for 4 hours; the pressure was reduced to normal pressure in 3 hours, and the system temperature was raised to 245°C, and then the reactor was evacuated to reduce the pressure to 1200 Pa (absolute pressure), and reacted for 2 hours to obtain PA1010 oligomer; (2) Preparation of L2 segment oligomer: 2.3 kg of 4,4'-diaminodicyclohexylmethane (PACM), 18.8 kg of polytetrahydrofuran ether diacid (number average molecular weight 1140) and 30 kg of deionized water were added to the second reactor, stirring was started, the temperature was raised to 190°C, and the reaction was carried out at a pressure of 1.3 MPa for 3 hours; the pressure was reduced to normal pressure within 3 hours, and the system temperature was raised to 230°C, and then the reactor was evacuated to reduce the pressure of the reactor to 500 Pa (absolute pressure), and the reaction was carried out for 2 hours to obtain a polyether oligomer; (3) Preparation of long-chain polyamide: The PA1010 oligomer obtained in step (1) and the polyether oligomer obtained in step (2) were placed in a third reactor, stirred, heated to 250°C, and the pressure of the reactor was reduced to 500 Pa (absolute pressure). The reaction was carried out for 3 hours. After extrusion, cooling, granulation, drying and packaging, a toughened transparent long-chain polyamide 1010 was obtained with a melt index of 9.5 g / 10 min (230°C, 2.16 kg).

[0017] Example 3 A method for preparing a toughened transparent long carbon chain polyamide comprises the following steps: (1) Preparation of L1 segment oligomer: 55.2 kg of dodecanedioic acid, 28.4 kg of hexamethylenediamine and 100 kg of deionized water were added to the first reactor, stirred, heated to 210°C, and reacted at a pressure of 1.9 MPa for 4 hours; the pressure was reduced to normal pressure in 3 hours, and the system temperature was raised to 250°C, then the reactor was evacuated and the pressure was reduced to 1500 Pa (absolute pressure), and the reaction was carried out for 2 hours to obtain PA612 oligomer; (2) Preparation of L2 segment oligomer: 2.1 kg of 4,4'-diaminodicyclohexylmethane (PACM), 17.1 kg of polytetrahydrofuran ether diacid (number average molecular weight 1140) and 30 kg of deionized water were added to the second reactor, stirring was started, the temperature was raised to 200°C, and the reaction was carried out at a pressure of 1.5 MPa for 3 hours; the pressure was reduced to normal pressure after 3 hours, and the system temperature was raised to 230°C, and then the reactor was evacuated and the pressure of the reactor was reduced to 500 Pa (absolute pressure). The reaction was carried out for 2 hours to obtain a polyether oligomer; (3) Preparation of long-chain polyamide: The PA612 oligomer obtained in step (1) and the polyether oligomer obtained in step (2) were placed in a third reactor, stirred, heated to 250°C, and the pressure of the reactor was reduced to 500 Pa (absolute pressure). The reaction was carried out for 3 hours. After extrusion, cooling, granulation, drying and packaging, a toughened transparent long-chain polyamide 612 was obtained with a melt index of 9.2 g / 10 min (230°C, 2.16 kg).

[0018] Example 4 A method for preparing a toughened transparent long carbon chain polyamide comprises the following steps: (1) Preparation of L1 segment oligomer: 48.3 kg of dodecanedioic acid, 37.3 kg of decanediamine and 120 kg of deionized water were added to the first reactor, stirred, heated to 190°C, and reacted at a pressure of 1.3 MPa for 4 hours; the pressure was reduced to normal pressure in 3 hours, and the system temperature was raised to 240°C, and then the reactor was evacuated and the pressure was reduced to 1000 Pa (absolute pressure). The reaction was continued for 2 hours to obtain PA1012 oligomer; (2) Preparation of L2 segment oligomer: 3.33 kg of 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane (MACM), 17.6 kg of polytetrahydrofuran ether diacid (number average molecular weight 840) and 30 kg of deionized water were added to the second reactor, stirring was started, the temperature was raised to 180°C, and the reaction was carried out at a pressure of 1.2 MPa for 3 hours; the pressure was reduced to normal pressure in 3 hours, and the system temperature was raised to 230°C, and then the reactor was evacuated to reduce the pressure of the reactor to 500 Pa (absolute pressure), and the reaction was carried out for 2 hours to obtain a polyether oligomer; (3) Preparation of long-chain polyamide: The PA1012 oligomer obtained in step (1) and the polyether oligomer obtained in step (2) were placed in a third reactor, stirred, heated to 250°C, and the pressure of the reactor was reduced to 500 Pa (absolute pressure). The reaction was carried out for 3 hours. After extrusion, cooling, granulation, drying and packaging, toughened transparent long-chain polyamide 1012 was obtained with a melt index of 11.6 g / 10 min (230°C, 2.16 kg).

[0019] Example 5 A method for preparing a toughened transparent long carbon chain polyamide comprises the following steps: (1) Preparation of L1 segment oligomer: 48.3 kg of dodecanedioic acid, 36.8 kg of decanediamine and 100 kg of deionized water were added to the first reactor, stirred, heated to 190°C, and reacted at a pressure of 1.3 MPa for 4 hours; the pressure was reduced to normal pressure in 3 hours, and the system temperature was raised to 240°C, and then the reactor was evacuated to reduce the pressure to 1000 Pa (absolute pressure), and reacted for 2 hours to obtain PA1012 oligomer; (2) Preparation of L2 segment oligomer: 2.0 kg of 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane (MACM), 14.4 kg of polytetrahydrofuran ether diacid (number average molecular weight 1140) and 28 kg of deionized water were added to the second reactor, stirring was started, and the temperature was raised to 180°C. The reaction was carried out at a pressure of 1.2 MPa for 3 hours. The pressure was reduced to normal pressure within 3 hours, and the system temperature was raised to 230°C. Then, the reactor was evacuated and the pressure was reduced to 500 Pa (absolute pressure). The reaction was carried out for 2 hours to obtain a polyether oligomer. (3) Preparation of long-chain polyamide: The PA1012 oligomer obtained in step (1) and the polyether oligomer obtained in step (2) were placed in a third reactor, stirred, heated to 250°C, and the pressure of the reactor was reduced to 500 Pa (absolute pressure). The reaction was carried out for 3 hours. After extrusion, cooling, granulation, drying and packaging, a toughened transparent long-chain polyamide 1012 was obtained with a melt index of 11.5 g / 10 min (230°C, 2.16 kg).

[0020] Comparative Example 1 A method for preparing a long carbon chain polyamide comprises the following steps: 57.5 kg of dodecanedioic acid, 43.1 kg of decanediamine and 100 kg of deionized water were added to the reactor, stirring was started, the temperature was raised to 200°C, and the reaction was carried out at a pressure of 1.5 MPa for 4 hours; the pressure was reduced to normal pressure in 3 hours, and the system temperature was raised to 250°C, and then the reactor was evacuated and the pressure was reduced to 1200 Pa (absolute pressure). The reaction was carried out for 2 hours. After extrusion, cooling, granulation, drying and packaging, PA1012 was obtained with a melt index of 9.7 g / 10min (230°C, 2.16 kg).

[0021] Comparative Example 2 A method for preparing a long carbon chain polyamide comprises the following steps: 45.5 kg of dodecanedioic acid, 37.1 kg of decanediamine, 20.52 kg of polytetrahydrofuran ether diacid (number average molecular weight 1140) and 120 kg of deionized water were added into a reactor, stirring was started, the temperature was raised to 190°C, and the reaction was carried out at a pressure of 1.3 MPa for 4 hours; the pressure was reduced to normal pressure in 3 hours, and the temperature of the system was raised to 240°C, and then the reactor was evacuated, the pressure of the reactor was reduced to 500 Pa (absolute pressure), and the reaction was carried out for 2 hours. After extrusion, cooling, granulation, drying and packaging, copolymerized long-chain polyamide 1012 was obtained, and the melt index was 10.4 g / 10min (230°C, 2.16 kg).

[0022] Comparative Example 3 A method for preparing a long carbon chain polyamide comprises the following steps: 46.1 kg of dodecanedioic acid, 35.3 kg of decanediamine, 2.1 kg of 4,4'-diaminodicyclohexylmethane (PACM), 17.1 kg of polytetrahydrofuran ether diacid (number average molecular weight 1140) and 120 kg of deionized water were added to the reactor, stirring was started, and the temperature was raised to 190°C. The reaction was carried out at a pressure of 1.3 MPa for 4 hours. The pressure was reduced to normal pressure in 3 hours, and the system temperature was raised to 240°C. Then the reactor was evacuated and the pressure of the reactor was reduced to 1000 Pa (absolute pressure). The reaction was carried out for 2 hours. After extrusion, cooling, granulation, drying and packaging, copolymerized long carbon chain polyamide 1012 was obtained, and the melt index was 11.1 g / 10min (230°C, 2.16 kg).

[0023] The long carbon chain polyamides prepared in Examples 1-5 and Comparative Examples 1-3 were subjected to performance tests, and the results are shown in Table 1.

[0024] Table 1 Performance test results of long carbon chain polyamides prepared in Examples 1-5 and Comparative Examples 1-3 It can be seen from the test data in Table 1 that Comparative Example 1 is a PA1012 base resin that is not copolymerized and modified (in order to obtain a product viscosity close to that of Example 1, the material ratio of Comparative Example 1 and Example 1 is different), Examples 1-5 introduce polyether copolymerization units, and the toughness and transparency of the toughened transparent long-chain polyamide obtained are greatly improved, and Comparative Example 2 introduces polyether as a copolymerization unit, but does not add alkyl-substituted bis(aminocyclohexyl)methane (same as Comparative Example 1, in order to obtain a product viscosity close to that of Example 1, the material ratio of Comparative Example 2 and Example 1 is different), and the transparency is lower than that of Example 1. Comparative Example 3 is a one-step copolymerization. Although the raw material composition is the same as that of Example 1, due to the random distribution of the monomers during the one-step reaction process, the alkyl-substituted bis(aminocyclohexyl)methane will be inserted into the long-chain polyamide chain segment, affecting the regularity of the long-chain polyamide chain segment. Although the transparency can be further improved, it also leads to a decrease in strength, affecting the use of the material.

[0025] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A toughened transparent long carbon chain polyamide, characterized in that: It is copolymerized by L1 segment oligomer and L2 segment oligomer, and its structural formula is: The terminal groups at both ends of the L1 segment oligomer are amine groups, which are formed by: 45-50 mol% of an aliphatic diacid and 50-55 mol% of an aliphatic diamine, wherein the carbon number of the aliphatic diacid is greater than or equal to 10, and the carbon number of the aliphatic diamine is greater than or equal to 6; The terminal groups at both ends of the L2 segment oligomer are carboxyl groups, which are formed by: 30-50 mol % of alkyl-substituted bis(aminocyclohexyl)methane and 50-70 mol % of carboxyl-terminated polyether.

2. The toughened transparent long carbon chain polyamide according to claim 1, characterized in that: The aliphatic diacid includes one or more of sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedicarboxylic acid, hexadecanedioic acid, heptadecanedioic acid and octadecanedicarboxylic acid.

3. The toughened transparent long carbon chain polyamide according to claim 1, characterized in that: The aliphatic diamine includes one or more of hexamethylenediamine, decamethylenediamine, undecanediamine, dodecamethylenediamine, tridecanediamine, tetradecanediamine, pentadecanediamine, hexadecamethylenediamine, heptadecamethylenediamine and octadecanediamine.

4. The toughened transparent long carbon chain polyamide according to claim 1, characterized in that: The alkyl-substituted bis(aminocyclohexyl)methane is 4,4'-diaminodicyclohexylmethane PACM or 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane MACM.

5. The toughened transparent long carbon chain polyamide according to claim 1, characterized in that: The carboxyl-terminated polyether is polytetrahydrofuran ether diacid with a number average molecular weight of 600-2000 or polyoxypropylene ether diacid with a number average molecular weight of 600-2000.

6. The toughened transparent long carbon chain polyamide according to claim 1, characterized in that: The amount of the L2 segment oligomer is 15-30% by weight, and the amount of the L1 segment oligomer is 70-85% by weight.

7. The method for preparing the toughened transparent long carbon chain polyamide according to any one of claims 1 to 6, characterized in that: The following steps are included: (1) Add 100 parts of aliphatic diacid, 40-100 parts of aliphatic diamine and 150-300 parts of deionized water into a reaction kettle by weight, start stirring, heat to 180-220° C., react at a pressure of 0.8-2.0 MPa for 2-8 hours; reduce the pressure to normal pressure after 2-5 hours, and raise the system temperature to 220-250° C., then evacuate the reaction kettle, reduce the pressure of the reaction kettle to an absolute pressure of 1000-2000 Pa, and react for 1-2 hours to obtain L1 segment oligomer; (2) Add 100 parts by weight of alkyl-substituted bis(aminocyclohexyl)methane, 400-1000 parts of carboxyl-terminated polyether and 500-1500 parts of deionized water into a reaction kettle, start stirring, heat to 180-220°C, react at a pressure of 0.8-2.0 MPa for 2-8 hours; reduce the pressure to normal pressure after 2-5 hours, and raise the system temperature to 220-250°C, then evacuate the reaction kettle, reduce the pressure of the reaction kettle to 500-1000 Pa absolute pressure, and react for 1-2 hours to obtain L2 segment oligomer; (3) Add L1 segment oligomer and L2 segment oligomer into a reactor, start stirring, heat to 220-250°C, and reduce the pressure of the reactor to an absolute pressure of 500-1000 Pa. React for 3-5 hours, and obtain toughened transparent long carbon chain polyamide through extrusion, cooling, granulation, drying and packaging.

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