Long-chain nylon resin with high gas barrier property and preparation method thereof

Abstract

The invention provides nylon 12 with high gas barrier property, a preparation method thereof and a product containing the nylon 12. The nylon 12 with the high gas barrier property comprises a segmented copolymer of a nylon 12 chain segment and a nylon 10I chain segment, and the ratio of the total mass of decamethylene diamine and isophthalic acid used in the preparation process to the mass of laurolactam is 1: (1-3). Compared with a random copolymer of nylon 12 and nylon 10I, the long-chain barrier nylon prepared by introducing a benzene ring-containing nylon 10I chain segment on a main chain of nylon 12 has the advantages that the molecular chain can still keep higher regularity and higher crystallinity, and the long-chain barrier nylon has better barrier performance and is easier to process and form.

Description

Technical Field

[0001] The present invention relates to the field of nylon, and more particularly to a long-chain nylon resin with high gas barrier properties for film processing and a preparation method thereof. Background Art

[0002] Nylon 12 has excellent toughness and flexibility, low water absorption, good dimensional stability, and is easy to process and shape. Due to the low water absorption of nylon 12, the water vapor permeability of nylon 12 film made of it is low, but because the carbon chain in nylon 12 is long, the density of amide bonds is low, and the rigidity of the molecular chain is small, the gas can easily diffuse through the gaps between molecules and within molecules in the nylon 12 film. Therefore, the oxygen permeability of nylon 12 is high and the gas barrier property is relatively poor. Therefore, the application of nylon 12 in food packaging films and the like is limited. Summary of the invention

[0003] The present invention prepares a long-chain nylon with good gas barrier properties by introducing a nylon 10I segment into a nylon 12 molecular chain. First, prepolymers of nylon 12 and nylon 10I are prepared respectively, and then the two prepolymers are post-polycondensed, and the polymerization process is optimized to obtain a long-chain nylon with higher segment regularity. The long-chain nylon has good gas barrier properties and low-temperature toughness, and is better in processing and molding, thereby achieving the purpose of the present invention.

[0004] According to a first aspect of the present invention, there is provided a nylon 12 with high gas barrier properties, which comprises a block copolymer of a nylon 12 segment and a nylon 10I segment, wherein the mass ratio of the total mass of decanediamine and isophthalic acid used in the preparation process to the mass ratio of lauryl lactam is 1:1-3, preferably 1:1.5-2.5, and more preferably 1:2.

[0005] Preferably, the relative solution viscosity of the high gas barrier nylon 12 is 1.9-2.0 when tested in a 0.5 g / dL m-cresol solution according to ISO1628-1:1998.

[0006] Preferably, by using a rapid scanning calorimeter to test, the long-chain nylon resin is first heated to 220°C at a rate of 10K / min, and then rapidly cooled to 20°C at a rate of 30K / min. It is measured that the crystallization heat release of the high gas barrier nylon 12 during the cooling process is 55 to 75 J / g, preferably 71 to 75 J / g.

[0007] Preferably, according to ISO 179-1:2022, the low-temperature notched impact strength of the high gas barrier nylon 12 is 6 kJ / m 2 More preferably 6.1 kJ / m 2 above.

[0008] Preferably, an oxygen permeability tester is used to test a 100 um cast film of the copolymer resin according to ISO 15105-2, and the helium permeability of the high gas barrier nylon 12 is 1200 cm 3 / (m 2 ·24h·0.1MPa) or less, more preferably 1000cm 3 / (m 2 ·24h·0.1MPa) or less.

[0009] According to a second aspect of the present invention, there is provided a method for preparing nylon 12 with high gas barrier properties, comprising the following steps:

[0010] (1) Add laurolactam, dibasic acid end-capping agent and water into a stirring container A, keep the mixture at 240-280° C. for 3-5 hours, maintain the reaction pressure at 2.5-4 MPa, then release the pressure of the reaction system to normal pressure, and react at -30-90 kPa to obtain a nylon 12 prepolymer;

[0011] (2) Add decanediamine, isophthalic acid, a diamine end-capping agent and water into a stirring container B, keep the mixture at 240 to 280° C. for 3 to 5 hours, maintain the reaction pressure at 2.5 to 4 MPa, then release the pressure of the reaction system to normal pressure, and react at -30 to 90 kPa to obtain a nylon 10I prepolymer;

[0012] (3) After transferring the nylon 12 prepolymer obtained in step (1) to a stirring container C, the nylon 10I prepolymer obtained in step (2) is added under stirring to react under negative pressure; then the discharged material is water-cooled and pelletized to obtain a long-chain nylon resin.

[0013] The mass ratio of the total mass of decanediamine and isophthalic acid to lauryl lactam is 1:1-3, preferably 1:1.5-2.5, and more preferably 1:2.

[0014] Preferably, in step (1), the reaction is carried out at -30 to 90 kPa for 0.5 to 1 h.

[0015] Preferably, in step (2), the reaction is carried out at -30 to 90 kPa for 0.5 to 1 h.

[0016] Preferably, in step (3), the temperature of the reaction system is 200-220° C., preferably 200-210° C.; the reaction pressure is 10-30 kPa; and the reaction time is 30-60 min, preferably 30-50 min.

[0017] Preferably, the dibasic acid end-capping agent is one or more selected from oxalic acid, adipic acid, sebacic acid, terephthalic acid and isophthalic acid, more preferably adipic acid.

[0018] Preferably, the diamine end-capping agent is one or more selected from ethylenediamine, hexamethylenediamine, p-phenylenediamine and m-phenylenediamine, more preferably hexamethylenediamine.

[0019] Preferably, the amount of the dibasic acid end-capping agent used is 0.5% to 3%, more preferably 1% to 1.5%, relative to the total mass of laurolactam in step (1).

[0020] Preferably, the amount of the diamine end-capping agent used is 0.5% to 3%, more preferably 1.5% to 2.5%, relative to the total mass of decanediamine and isobenzoic acid in step (2).

[0021] Preferably, the amount of water used in step (1) is 5% to 15%, more preferably 10%, relative to the total mass of laurolactam in step (1).

[0022] Preferably, the amount of water in step (2) is 5% to 15%, more preferably 10%, relative to the total mass of decanediamine and isobenzoic acid in step (2).

[0023] Preferably, the molar ratio of the dibasic acid end-capping agent to the diamine end-capping agent is (1.03-1.07):1, preferably 1.05:1.

[0024] Preferably, the relative solution viscosity of the nylon 12 with high gas barrier properties described in the present invention is 1.9 to 2.0 when tested in a 0.5 g / dL m-cresol solution according to ISO1628-1:1998.

[0025] Preferably, by using a rapid scanning calorimeter to test, the long-chain nylon resin is first heated to 220°C at a rate of 10K / min, and then rapidly cooled to 20°C at a rate of 30K / min. It is measured that the crystallization heat release of the high gas barrier nylon 12 described in the present invention during the cooling process is 55-75J / g, preferably 60-75J / g.

[0026] According to a third aspect of the present invention, there is provided a product comprising the nylon 12 with high gas barrier properties according to the present invention.

[0027] The longer the chain, the greater the heat release. The more regular the chain segments are.

[0028] The technical solution provided by the present invention has the following beneficial effects:

[0029] (1) In the present invention, a nylon 10I segment containing a benzene ring is introduced into the main chain of nylon 12 to prepare a long-chain barrier nylon. Compared with the random copolymer of nylon 12 and nylon 10I, the molecular chain of the long-chain barrier nylon can still maintain a high degree of regularity and a higher degree of crystallinity. While having good barrier properties, it is easier to process and shape.

[0030] (2) The polymerization of the nylon resin in the present invention is divided into four steps. Step 1 and step 2 respectively obtain a carboxyl-terminated nylon 12 prepolymer and an amino-terminated nylon 10I prepolymer. In step 2, after the nylon 12 prepolymer and the nylon 10I prepolymer are fully mixed, the degree of amide exchange reaction in the reaction system is suppressed by controlling the reaction temperature and the reaction steam pressure, thereby obtaining a long-chain nylon resin with higher chain segment regularity. DETAILED DESCRIPTION

[0031] In order to better understand the technical solution of the present invention, the content of the present invention is further described below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0032] The present invention is further described below in conjunction with specific embodiments, but the present invention is not limited to the following embodiments.

[0033] Lauryl lactam is purchased from Wanhua Chemical, adipic acid and hexamethylenediamine are purchased from Henan Shenma, and isophthalic acid, tris(propane) acid and isophthalic acid are purchased from Aldrich.

[0034] Relative viscosity is measured in 0.5 g / dL m-cresol solution according to ISO 1628-1:1998.

[0035] The crystallization rate and melting endotherm of nylon 12 resin were tested by using a rapid scanning calorimeter. The long-chain nylon resin was first heated to 220°C at a rate of 10K / min and then rapidly cooled to 20°C at a rate of 30K / min. It was found that the greater the crystallization exotherm and the higher the melting peak during the cooling process, the higher the chain regularity of the nylon resin.

[0036] Low temperature notched impact strength is tested at -30°C according to ISO 179-1:2022.

[0037] The helium permeability is measured by testing a 100 um cast film of the copolymer resin using an oxygen permeability tester according to ISO 15105-2.

[0038] Comparative Example 1

[0039] In a 1m 3 Into a stirring container, 200 kg of lauryl lactam, 30 kg of water, 3 kg of adipic acid, 50.91 kg of decanediamine and 49.09 kg of isophthalic acid were added, and the temperature was raised to 260 ° C and kept for 3 hours. The pressure was maintained at 3.3 MPa. Subsequently, the reaction system was depressurized to normal pressure and maintained at a vacuum degree of less than -60 kPa at 240 ° C for 60 minutes. The material was discharged at 240 ° C and water-cooled and pelletized to obtain nylon resin.

[0040] Comparative Example 2

[0041] 1) In a 0.5m 3 In a stirring container, 200 kg of lauryl lactam, 20 kg of water, and 2 kg of adipic acid were added, and the temperature was raised to 260° C. and kept for 3 hours, and the pressure was maintained at 3.5 MPa. Then, the system was depressurized to normal pressure, and after vacuuming to -60 kPa at 240° C., the reaction system was kept for 0.5 hour to obtain a nylon 12 prepolymer;

[0042] 2) In a 0.5m 3 In a stirring container, 50.91 kg of decanediamine, 49.09 kg of isophthalic acid, 10 kg of water, and 1.515 kg of hexamethylenediamine were added, and the temperature was raised to 260 ° C and kept for 3 hours, and the pressure was maintained at 2.7 MPa. Then the system was depressurized to normal pressure, and after vacuuming to -60 kPa at 240 ° C, the reaction system was kept for 0.5 hours to obtain a prepolymer of nylon 10I;

[0043] 3) Transfer the nylon 12 prepolymer obtained in step (1) to a 1m 3 After the stirring container is prepared, the nylon 10I prepolymer obtained in step (2) is added under stirring, the temperature of the reaction system is controlled at 240°C, and the reaction is carried out at -60 kPa for 30 minutes. The reaction system is then restored to normal pressure, and the discharged material is water-cooled and pelletized to obtain a long-chain nylon resin.

[0044] Example 1

[0045] 1) obtaining a nylon 12 prepolymer and a nylon 10I prepolymer by referring to step (1) and step (2) of comparative example 2;

[0046] 2) Transfer the obtained nylon 12 prepolymer to a 1m 3 After the stirring container is prepared, nylon 10I prepolymer is added under stirring, the temperature of the reaction system is controlled at 200°C, and the reaction is carried out under a steam pressure of 10 kPa for 30 minutes. The discharged material is water-cooled and pelletized to obtain a long-chain nylon resin.

[0047] Example 2

[0048] 1) obtaining a nylon 12 prepolymer and a nylon 10I prepolymer by referring to step (1) and step (2) of comparative example 2;

[0049] 2) Transfer the obtained nylon 12 prepolymer to a 1m 3 After the stirring container is prepared, nylon 10I prepolymer is added under stirring, the temperature of the reaction system is controlled at 200°C, and the reaction is carried out under a steam pressure of 10 kPa for 45 minutes. The discharged material is water-cooled and pelletized to obtain a long-chain nylon resin.

[0050] Example 3

[0051] 1) obtaining a nylon 12 prepolymer and a nylon 10I prepolymer by referring to step (1) and step (2) of comparative example 2;

[0052] 2) Transfer the obtained nylon 12 prepolymer to a 1m 3 After the stirring container is prepared, nylon 10I prepolymer is added under stirring, the temperature of the reaction system is controlled at 210°C, and the reaction is carried out under a steam pressure of 10 kPa for 45 minutes. The discharged material is water-cooled and pelletized to obtain a long-chain nylon resin.

[0053] Example 4

[0054] 1) obtaining a nylon 12 prepolymer and a nylon 10I prepolymer by referring to step (1) and step (2) of comparative example 2;

[0055] 2) Transfer the obtained nylon 12 prepolymer to a 1m 3 After the stirring container is prepared, nylon 10I prepolymer is added under stirring, the temperature of the reaction system is controlled at 210°C, and the reaction is carried out under a steam pressure of 20 kPa for 45 minutes. The discharged material is water-cooled and pelletized to obtain a long-chain nylon resin.

[0056] Example 5

[0057] 1) obtaining a nylon 12 prepolymer and a nylon 10I prepolymer by referring to step (1) and step (2) of comparative example 2;

[0058] 2) Transfer the obtained nylon 12 prepolymer to a 1m 3 After the stirring container is prepared, nylon 10I prepolymer is added under stirring, the temperature of the reaction system is controlled at 210°C, and the reaction is carried out under a steam pressure of 30 kPa for 45 minutes. The discharged material is water-cooled and pelletized to obtain a long-chain nylon resin.

[0059] Example 6

[0060] 1) In a 0.5m 3 In a stirring container, 300 kg of lauryl lactam, 30 kg of water, and 3 kg of adipic acid were added, and the temperature was raised to 260° C. and kept for 3 hours, and the pressure was maintained at 4 MPa. Then, the system was depressurized to normal pressure, and after vacuuming to -60 kPa at 240° C., the reaction system was kept for 0.5 hours to obtain a nylon 12 prepolymer;

[0061] 2) In a 0.5m 3 In a stirring container, 50.91 kg of decanediamine, 49.09 kg of isophthalic acid, 10 kg of water, and 2.272 kg of hexamethylenediamine were added, and the temperature was raised to 260 ° C and kept for 3 hours, and the pressure was maintained at 2.5 MPa. Then the system was depressurized to normal pressure, and after vacuuming to -60 kPa at 240 ° C, the reaction system was kept for 0.5 hours to obtain a prepolymer of nylon 10I;

[0062] 3) Transfer the nylon 12 prepolymer obtained in step (1) to a 1m 3 After the stirring container is prepared, the nylon 10I prepolymer obtained in step (2) is added under stirring, the temperature of the reaction system is controlled at 210° C., and the reaction is carried out at a steam pressure of 20 kPa for 45 minutes. The discharged material is water-cooled and pelletized to obtain a long-chain nylon resin.

[0063] Example 7

[0064] 1) obtaining a prepolymer of nylon 12 by referring to step (1) of Comparative Example 2;

[0065] 2) In a 0.5m 3 In a stirring container, 101.83 kg of decanediamine, 98.17 kg of isophthalic acid, 10 kg of water, and 1.515 kg of hexamethylenediamine were added, and the temperature was raised to 260 ° C and kept for 3 hours, and the pressure was maintained at 3 MPa. Then the system was depressurized to normal pressure, and after vacuuming to -60 kPa at 240 ° C, the reaction system was kept for 0.5 hours to obtain a prepolymer of nylon 10I;

[0066] 3) Transfer the obtained nylon 12 prepolymer to a 1m 3 After the stirring container is prepared, nylon 10I prepolymer is added under stirring, the temperature of the reaction system is controlled at 210°C, and the reaction is carried out under a steam pressure of 30 kPa for 45 minutes. The discharged material is water-cooled and pelletized to obtain a long-chain nylon resin.

[0067] The long-chain nylon resins obtained in Comparative Examples 1-2 and Examples 1-7 were tested for relative viscosity, low-temperature notched impact strength, helium permeability, and heat release during the cooling process in the DSC test.

[0068] Table 1: Test results of long-chain nylon resins in Comparative Examples 1-2 and Examples 1-7

[0069]

[0070] Those skilled in the art will appreciate that, based on the teachings of this specification, some modifications or adjustments may be made to the present invention, and these modifications or adjustments should also be within the scope defined by the claims of the present invention.

Claims

1. A nylon 12 with high gas barrier properties, comprising a block copolymer of a nylon 12 segment and a nylon 10I segment, wherein: The mass ratio of the total mass of decanediamine and isophthalic acid to lauryl lactam used in the preparation process is 1:1-3, preferably 1:1.5-2.5, and more preferably 1:

2.

2. The high gas barrier nylon 12 according to claim 1, wherein According to ISO1628-1:1998, the relative solution viscosity of the high gas barrier nylon 12 is tested in a 0.5 g / dL m-cresol solution, and is 1.9-2.

0.

3. The high gas barrier nylon 12 according to claim 1 or 2, wherein: By using a rapid scanning calorimeter to test, the long-chain nylon resin was first heated to 220°C at a rate of 10K / min, and then quickly cooled to 20°C at a rate of 30K / min. It was measured that the crystallization heat release of the high gas barrier nylon 12 during the cooling process was 55-75J / g, preferably 71-75J / g.

4. The high gas barrier nylon 12 according to any one of claims 1 to 3, wherein According to ISO 179-1:2022, the low-temperature notched impact strength of the high gas barrier nylon 12 is 6 kJ / m at -30°C. 2 Above, preferably 6.1 kJ / m 2 above.

5. The high gas barrier nylon 12 according to any one of claims 1 to 4, wherein The 100um cast film of the copolymer resin was tested using an oxygen permeability tester according to ISO 15105-2. The helium permeability of the high gas barrier nylon 12 was 1200cm 3 / (m 2 ·24h·0.1MPa) or less, preferably 1000cm 3 / (m 2 ·24h·0.1MPa) or less.

6. A method for preparing nylon 12 with high gas barrier properties, comprising the following steps: (1) Add laurolactam, dibasic acid end-capping agent and water into a stirring container A, keep the mixture at 240-280° C. for 3-5 hours, maintain the reaction pressure at 2.5-4 MPa, then release the pressure of the reaction system to normal pressure, and react at -30-90 kPa to obtain a nylon 12 prepolymer; (2) Add decanediamine, isophthalic acid, a diamine end-capping agent and water into a stirring container B, keep the mixture at 240 to 280° C. for 3 to 5 hours, maintain the reaction pressure at 2.5 to 4 MPa, then release the pressure of the reaction system to normal pressure, and react at -30 to 90 kPa to obtain a nylon 10I prepolymer; (3) After transferring the nylon 12 prepolymer obtained in step (1) to a stirring container C, the nylon 10I prepolymer obtained in step (2) is added under stirring, and the reaction is carried out under negative pressure, and then the discharged material is water-cooled and pelletized to obtain a long-chain nylon resin. The mass ratio of the total mass of decanediamine and isophthalic acid to lauryl lactam is 1:1-3, preferably 1:1.5-2.5, and more preferably 1:

2.

7. The method for preparing nylon 12 with high gas barrier properties according to claim 6, wherein: In step (1), the reaction is carried out at -30 to 90 kPa for 0.5 to 1 h; And / or, in step (2), reacting at -30 to 90 kPa for 0.5 to 1 h; And / or, in step (3), the reaction system temperature is 200-220° C., preferably 200-210° C.; the reaction pressure is 10-30 kPa; and the reaction time is 30-60 min, preferably 30-50 min.

8. The method for preparing nylon 12 with high gas barrier properties according to claim 6 or 7, wherein: The dibasic acid end-capping agent is one or more selected from oxalic acid, adipic acid, sebacic acid, terephthalic acid and isophthalic acid, preferably adipic acid; and / or, the diamine end-capping agent is one or more selected from ethylenediamine, hexamethylenediamine, p-phenylenediamine and m-phenylenediamine, preferably hexamethylenediamine; and / or, relative to the total mass of laurolactam in step (1), the amount of the dibasic acid end-capping agent is 0.5% to 3%, more preferably 1% to 1.5%; And / or, relative to the total mass of decanediamine and isobenzoic acid in step (2), the amount of the diamine end-capping agent is 0.5% to 3%, preferably 1.5% to 2.5%.

9. The method for preparing nylon 12 with high gas barrier properties according to any one of claims 6 to 8, wherein: Relative to the total mass of laurolactam in step (1), the amount of water in step (1) is 5% to 15%, preferably 10%; and / or, relative to the total mass of decanediamine and isobenzoic acid in step (2), the amount of water in step (2) is 5% to 15%, preferably 10%; And / or, the molar ratio of the dibasic acid end-capping agent to the diamine end-capping agent is (1.03-1.07):1, preferably 1.05:

1.

10. An article comprising the high gas barrier nylon 12 according to any one of claims 1 to 5.

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