Long carbon chain transparent nylon based on PACM copolymerization modification and preparation method thereof

Abstract

The invention discloses long-carbon-chain transparent nylon based on PACM copolymerization modification and a preparation method thereof.The preparation method of the long-carbon-chain transparent nylon comprises the steps that dodecanedioic acid and water are evenly mixed, a first mixture is obtained, a second mixture is added into the first mixture, a salt forming reaction is conducted, after the salt forming reaction is finished, the temperature is increased to 190-230 DEG C in the protective atmosphere, and the long-carbon-chain transparent nylon is obtained; adding a catalyst and an antioxidant for carrying out a pre-polycondensation reaction, after the pre-polycondensation reaction is finished, heating to 250-270 DEG C for carrying out a vacuum polycondensation reaction, cooling to room temperature, and granulating to obtain the long carbon chain transparent nylon based on PACM copolymerization modification; the second mixture is a mixture of 1, 6-hexamethylenediamine, 4, 4 '-diaminodicyclohexylmethane and water, and the long-carbon-chain transparent nylon has the advantages of good transparency, good toughness, good wear resistance, low water absorption, good dimensional stability and excellent mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of transparent nylon polymer materials, specifically relating to a long-chain transparent nylon based on PACM copolymerization modification and its preparation method. Background Technology

[0002] Polyamide (PA), commonly known as nylon, is a linear thermoplastic polymer with a large number of amide groups on its molecular chain. It possesses good abrasion resistance, excellent thermal stability, good toughness, and processability. Compared to short-chain nylon, long-chain nylon has a lower amide bond density, resulting in lower water absorption, better dimensional stability, and superior dielectric properties. Furthermore, the large number of methylene groups on the long-chain nylon molecular chain imparts good flexibility and high segment regularity, giving it strong crystallinity and excellent toughness. However, long-chain nylon has poor transparency, and its transparency modification technology is difficult to achieve, which limits its application in lighting, optical instruments, and transparent packaging materials.

[0003] Currently, transparent nylons both domestically and internationally are mainly semi-aromatic nylons and their blends, such as DuPont's Zytel and Selar series, EMS's Grilamide series, and Kingfa Science & Technology's PA6T / 6I. However, the benzene ring structure in the macromolecular chain of semi-aromatic transparent nylons degrades their UV resistance, limiting their application in specific scenarios. Research has found that aliphatic transparent nylons can effectively solve this problem. Introducing alicyclic structures into long-chain nylons disrupts the regularity of their macromolecular chains, reduces their crystallinity, and improves their transparency and toughness.

[0004] There are two main techniques for the transparent modification of long-chain nylon: one is blending modification, which involves adding nucleating agents or quenching to the glass transition temperature T. gThe first method inhibits crystallization, but it is prone to thermal crystallization at high temperatures, resulting in a loss of high transparency and limiting its application. The second method is copolymerization modification, which weakens the crystallization ability by introducing molecular structures that disrupt chain regularity, thereby fundamentally improving its transparency. Patent CN114716667A uses nylon 66 salt, hexamethylenediamine, bismaleimide, and antioxidants to prepare transparent nylon with high tensile strength and good light transmittance. However, due to the short-chain structure of its nylon salt, it has a high water absorption rate, poor dimensional stability, and insufficient toughness. Patent CN115975181A discloses a method for preparing ternary copolymer transparent nylon, which is obtained through copolymerization of three nylons: alicyclic transparent nylon, long-chain transparent nylon, and PA6T nylon. The resulting transparent nylon has high light transmittance and tensile strength, but the preparation process is complex, the conditions are harsh, and the molecular weight of the product is low. Patent CN119285935A uses segments obtained by copolymerizing alicyclic diamines with carboxyl-terminated polyethers to copolymerize and modify long-chain nylon, achieving high transparency and toughening effects. However, the two-step polycondensation process it uses is relatively complex, and the tensile strength of the synthesized copolymer nylon is low. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a long-chain transparent nylon based on PACM copolymer modification.

[0006] Another object of the present invention is to provide a method for preparing the above-mentioned long carbon chain transparent nylon. This method introduces the alicyclic structure of 4,4'-diaminodicyclohexylmethane (PACM) into PA612 through a one-pot melt polycondensation process, thereby disrupting the regularity of the molecular chain structure of PA612, reducing its crystallinity, and improving the transparency and toughness of the long carbon chain nylon.

[0007] The objective of this invention is achieved through the following technical solutions.

[0008] A long-chain transparent nylon (PA612 / PACM12) based on PACM copolymerization modification has the following structural formula:

[0009] , where m∶n=(1~4)∶(6~9).

[0010] The above-mentioned method for preparing long-chain transparent nylon (PA612 / PACM12) based on PACM copolymerization modification includes: mixing dodecanoic acid and water uniformly to obtain a first mixture; adding a second mixture to the first mixture to carry out a salt formation reaction; after the salt formation reaction is completed, heating to 190~230℃ under a protective atmosphere; adding a catalyst and antioxidant for a pre-condensation reaction; after the pre-condensation reaction is completed, heating to 250~270℃ for a vacuum condensation reaction; cooling to room temperature; and granulating to obtain long-chain transparent nylon (PA612 / PACM12) based on PACM copolymerization modification.

[0011] The second mixture is a mixture of 1,6-hexanediamine, 4,4'-diaminodicyclohexylmethane (PACM) and water, and the ratio of the sum of 1,6-hexanediamine and 4,4'-diaminodicyclohexylmethane (PACM) to water in the second mixture is 1:(2~3) by mass.

[0012] The ratio of dodecanoic acid, 1,6-hexanediamine and 4,4'-diaminodicyclohexylmethane (PACM) by molar amounts is 200:(120~180):(20~80).

[0013] The antioxidant is one or a mixture of antioxidant 168 and antioxidant 1010.

[0014] In the above technical solution, the ratio of dodecanoic acid to water in the first mixture is 1:(2~3) by mass.

[0015] In the above technical solution, the uniform mixing includes stirring at 60~90℃ for 15~30 minutes.

[0016] In the above technical solution, the stirring speed is 30~60 rpm.

[0017] In the above technical solution, the temperature of the salt formation reaction is 70~90℃, and the time of the salt formation reaction is 2~5h.

[0018] In the above technical solution, the protective atmosphere includes nitrogen.

[0019] In the above technical solution, the pre-condensation reaction time is 2-4 hours.

[0020] In the above technical solution, the vacuum polycondensation reaction time is 3~5h, and the vacuum degree during the vacuum polycondensation reaction is ≤200Pa.

[0021] In the above technical solution, the catalyst is one or more of potassium phosphite, sodium phosphite, magnesium phosphite, potassium hypophosphite, sodium hypophosphite, and magnesium hypophosphite.

[0022] In the above technical solution, the ratio of dodecanoic acid, catalyst and antioxidant by mass parts is 1:(0.001~0.005):(0.001~0.005).

[0023] In the above technical solution, the granulation speed is 15~20 r / s.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1. The long carbon chain transparent nylon modified by PACM copolymerization of the present invention has good transparency, good toughness, good wear resistance, low water absorption, good dimensional stability, and excellent mechanical properties. The light transmittance is as high as 92.8%, the yield strength is higher than 55MPa, and the elongation at break can reach up to 232.394%.

[0026] 2. The preparation method of the present invention adopts the one-pot melt polycondensation method, which is simple and easy to implement, has low cost, and is conducive to industrial expansion and shortening of production cycle.

[0027] 3. In the preparation method of this invention, PA612, as a long-chain nylon, has low water absorption, good dimensional stability, and high tensile and impact strength. The monomer hexamethylenediamine used is a commonly used nylon monomer with low cost. At the same time, dodecanoic acid, as a bio-based diacid, conforms to the current sustainable development strategy. Using deionized water as a solvent is not only green and environmentally friendly and low in cost, but also avoids the problems of end-capping and low molecular weight of the product caused by the reaction of ethanol with the carboxyl groups in the reactant monomer. By introducing the alicyclic structure PACM into PA612, the regularity of its molecular chain structure is disrupted, its crystallinity is reduced, the transparency of PA612 is improved, and its toughness is enhanced, which is expected to expand the application range of PA612. Attached Figure Description

[0028] Figure 1 The transmittance curves are for PACM copolymer-modified long-chain transparent nylon in Examples 1-6, long-chain nylon in Comparative Examples 1-2, and long-chain transparent nylon in Comparative Examples 3-5.

[0029] Figure 2 The DSC curves are for PACM copolymerized long-chain transparent nylon in Examples 1 and 4-6, long-chain nylon in Comparative Example 1, and long-chain transparent nylon in Comparative Examples 3-5, where (a) is the DSC heating curve and (b) is the DSC cooling curve.

[0030] Figure 3 (a) 1H NMR spectra and (b) NMR spectra of PACM copolymerized long-chain transparent nylon in Examples 1 and 4-6, and long-chain nylon in Comparative Example 1. Figure 3 A magnified view of the area within the dashed box in (a). Detailed Implementation

[0031] The technical solution of the present invention will be described in detail below with reference to the embodiments and accompanying drawings.

[0032] In the following examples, the water used is deionized water.

[0033] The purity and source of the reagents used in the following examples are as follows:

[0034] Dodecanoic acid (99.8%), 1,6-hexanediamine (99.8%), 4,4'-diaminodicyclohexylmethane (PACM, 99.5%), antioxidant 626 (99.5%), antioxidant 168 (99.5%), potassium phosphite (99.8%), and sulfuric acid (18 mol / L) were all purchased from Aladdin Reagent Co., Ltd., Shanghai, China.

[0035] The instrument models and manufacturers used in the following examples are as follows:

[0036] Bruker AVIII 400 MRI scanner, Bruker Corporation;

[0037] Instron 1122 Electronic Universal Testing Machine, Shenzhen Sanshi Company, China;

[0038] DSC204F1 Differential Scanning Calorimeter, Netzsch Instruments GmbH, Germany;

[0039] UH4150 Ultraviolet-Vis Spectrometer, Hitachi Scientific Instruments Co., Ltd.

[0040] WD-120 haze meter, Jinan Sanquan Zhongshi Experimental Instrument Co., Ltd.;

[0041] Icon atomic force microscope, Bruker Corporation;

[0042] LQ-25 high-speed pelletizer, Jiangsu Zhenghong Rubber & Plastic Machinery Manufacturing Co., Ltd.

[0043] SY-6216-B Single Screw Extruder, Dongguan Shiyan Precision Instruments Co., Ltd.

[0044] In the following embodiments, the granulation is performed using a high-speed pelletizer with a granulation speed of 15 r / s, and the size of the granulated particles is ø3×3 mm.

[0045] Example 1

[0046] A method for preparing long-chain transparent nylon (PA612 / PACM12) based on PACM copolymerization modification includes: mixing dodecanoic acid and water, stirring at 75°C for 30 min to obtain a first mixture, wherein the ratio of dodecanoic acid to water in the first mixture is 1:2 by mass; slowly adding a second mixture to the first mixture; carrying out a salt formation reaction at 75°C for 3 h; raising the temperature to T1°C under a protective atmosphere (nitrogen); adding a catalyst (potassium phosphite) and an antioxidant (antioxidant 168); carrying out a pre-condensation reaction for 2 h; then raising the temperature to T2°C; carrying out a vacuum condensation reaction for 5 h (the vacuum degree during the vacuum condensation reaction should be ≤200 Pa); cooling to room temperature; and granulating to obtain a product based on PACM copolymerization modification. PACM copolymerized modified long-chain transparent nylon (PA612 / PACM12), wherein the second mixture is a mixture of 1,6-hexanediamine, 4,4'-diaminodicyclohexylmethane (PACM) and water, and the ratio of the sum of 1,6-hexanediamine and 4,4'-diaminodicyclohexylmethane (PACM) to water in the second mixture is 1:2 by mass; the ratio of dodecanoic acid, 1,6-hexanediamine and 4,4'-diaminodicyclohexylmethane (PACM) is 200:180:20 by mass; and the ratio of dodecanoic acid, catalyst and antioxidant is 1:0.005:0.005 by mass; wherein T1=190 and T2=250.

[0047] The structural formula of the obtained PACM copolymer-modified long-chain transparent nylon (PA612 / PACM12) is as follows:

[0048] ,

[0049] Where m∶n=1∶9.

[0050] Example 2

[0051] A method for preparing long-chain transparent nylon (PA612 / PACM12) based on PACM copolymerization modification is basically the same as that in Example 1, except that the antioxidant is antioxidant 626.

[0052] The structural formula of the obtained PACM copolymer-modified long-chain transparent nylon (PA612 / PACM12) is as follows:

[0053] ,

[0054] Where m∶n=1∶9.

[0055] Example 3 (for comparison)

[0056] A method for preparing long-chain transparent nylon (PA612 / PACM12) based on PACM copolymerization modification is basically the same as that in Example 1, except that the salt formation reaction time is 2 hours.

[0057] Example 4

[0058] A method for preparing long-chain transparent nylon (PA612 / PACM12) based on PACM copolymerization modification includes: mixing dodecanoic acid and water, stirring at 80°C for 30 min to obtain a first mixture, wherein the ratio of dodecanoic acid to water in the first mixture is 1:2 by mass; slowly adding a second mixture to the first mixture; carrying out a salt formation reaction at 80°C for 3 h; raising the temperature to T1°C under a protective atmosphere (nitrogen); adding a catalyst (potassium phosphite) and an antioxidant (antioxidant 168); carrying out a pre-condensation reaction for 2 h; then raising the temperature to T2°C; carrying out a vacuum condensation reaction for 5 h (the vacuum degree during the vacuum condensation reaction should be ≤200 Pa); cooling to room temperature; and granulating to obtain a product based on PACM copolymerization modification. PACM copolymerized modified long-chain transparent nylon (PA612 / PACM12), wherein the second mixture is a mixture of 1,6-hexanediamine, 4,4'-diaminodicyclohexylmethane (PACM) and water, and the ratio of the sum of 1,6-hexanediamine and 4,4'-diaminodicyclohexylmethane (PACM) to water in the second mixture is 1:2 by mass; the ratio of dodecanoic acid, 1,6-hexanediamine and 4,4'-diaminodicyclohexylmethane (PACM) is 200:160:40 by mass; and the ratio of dodecanoic acid, catalyst and antioxidant is 1:0.005:0.005 by mass; wherein T1=200, T2=255.

[0059] The structural formula of the obtained PACM copolymer-modified long-chain transparent nylon (PA612 / PACM12) is as follows:

[0060] ,

[0061] Where m∶n=2∶8.

[0062] Example 5

[0063] A method for preparing long-chain transparent nylon (PA612 / PACM12) based on PACM copolymerization modification includes: mixing dodecanoic acid and water, stirring at 85°C for 30 min to obtain a first mixture, wherein the ratio of dodecanoic acid to water in the first mixture is 1:2 by mass; slowly adding a second mixture to the first mixture; carrying out a salt formation reaction at 85°C for 3 h; raising the temperature to T1°C under a protective atmosphere (nitrogen); adding a catalyst (potassium phosphite) and an antioxidant (antioxidant 168); carrying out a pre-condensation reaction for 2 h; then raising the temperature to T2°C; carrying out a vacuum condensation reaction for 5 h (the vacuum degree during the vacuum condensation reaction should be ≤200 Pa); cooling to room temperature; and granulating to obtain a product based on PACM copolymerization modification. PACM copolymerized modified long-chain transparent nylon (PA612 / PACM12), wherein the second mixture is a mixture of 1,6-hexanediamine, 4,4'-diaminodicyclohexylmethane (PACM) and water, and the ratio of the sum of 1,6-hexanediamine and 4,4'-diaminodicyclohexylmethane (PACM) to water in the second mixture is 1:2 by mass; the ratio of dodecanoic acid, 1,6-hexanediamine and 4,4'-diaminodicyclohexylmethane (PACM) is 200:140:60 by mass; and the ratio of dodecanoic acid, catalyst and antioxidant is 1:0.005:0.005 by mass; wherein T1=210, T2=260.

[0064] The structural formula of the obtained PACM copolymer-modified long-chain transparent nylon (PA612 / PACM12) is as follows:

[0065] ,

[0066] Where m∶n=3∶7.

[0067] Example 6

[0068] A method for preparing long-chain transparent nylon (PA612 / PACM12) based on PACM copolymerization modification includes: mixing dodecanoic acid and water, stirring at 90°C for 30 min to obtain a first mixture, wherein the ratio of dodecanoic acid to water in the first mixture is 1:2 by mass; slowly adding a second mixture to the first mixture; carrying out a salt formation reaction at 90°C for 3 h; heating to T1°C under a protective atmosphere (nitrogen); adding a catalyst (potassium phosphite) and an antioxidant (antioxidant 168); carrying out a pre-condensation reaction for 2 h; then heating to T2°C; carrying out a vacuum condensation reaction for 5 h (the vacuum degree during the vacuum condensation reaction should be ≤200 Pa); cooling to room temperature; and granulating to obtain a product based on PACM copolymerization modification. PACM copolymerized modified long-chain transparent nylon (PA612 / PACM12), wherein the second mixture is a mixture of 1,6-hexanediamine, 4,4'-diaminodicyclohexylmethane (PACM) and water, and the ratio of the sum of 1,6-hexanediamine and 4,4'-diaminodicyclohexylmethane (PACM) to water in the second mixture is 1:2 by mass; the ratio of dodecanoic acid, 1,6-hexanediamine and 4,4'-diaminodicyclohexylmethane (PACM) is 200:120:80 by mass; and the ratio of dodecanoic acid, catalyst and antioxidant is 1:0.005:0.005 by mass; wherein, T1=220, T2=265.

[0069] The structural formula of the obtained PACM copolymer-modified long-chain transparent nylon (PA612 / PACM12) is as follows:

[0070] ,

[0071] Where m∶n=4∶6.

[0072] Comparative Example 1

[0073] A method for preparing long-chain nylon (PA612) includes: mixing dodecanoic acid, 1,6-hexanediamine, and water, and carrying out a salt-forming reaction at 90°C for 3 hours; then heating to T1°C under a protective atmosphere (nitrogen), adding a catalyst (potassium phosphite) and an antioxidant (antioxidant 168), and carrying out a pre-condensation reaction for 2 hours; then heating to T2°C and carrying out a vacuum condensation reaction for 5 hours (the vacuum degree of the vacuum condensation reaction should be ≤200Pa); and finally cooling to room temperature. The mixture was granulated at a certain temperature to obtain long-chain nylon (PA612), wherein the mass ratio of dodecanoic acid, 1,6-hexanediamine and water was 200:200:138.4, where the mass ratio is in mol and the mass ratio is in kg. The mass ratio of dodecanoic acid, catalyst and antioxidant was 1:0.005:0.005. T1=190, T2=250.

[0074] The structural formula of the obtained long-chain carbon nylon is:

[0075] .

[0076] Comparative Example 2

[0077] A method for preparing long-chain nylon (PA1012) includes: mixing dodecanoic acid, 1,10-decanediamine, and water, and carrying out a salt-forming reaction at 90°C for 3 hours; heating to T1°C under a protective atmosphere (nitrogen), adding a catalyst (potassium phosphite) and an antioxidant (antioxidant 168), and carrying out a pre-condensation reaction for 2 hours; then heating to T2°C and carrying out a vacuum condensation reaction for 5 hours (the vacuum degree of the vacuum condensation reaction should be ≤200Pa); and cooling to room temperature. The mixture was granulated at a certain temperature to obtain long-chain nylon (PA612), wherein the molar ratio of dodecanoic acid, 1,10-decanediamine and water was 200:200:160.92, with the molar ratio in mol and the mass ratio in kg; the mass ratio of dodecanoic acid, catalyst and antioxidant was 1:0.005:0.005; T1=190, T2=250.

[0078] The structural formula of the obtained long-chain carbon nylon is:

[0079] .

[0080] Comparative Example 3

[0081] A method for preparing long-chain transparent nylon includes: mixing dodecanoic acid and water, stirring at 90°C for 30 min to obtain a first mixture, wherein the ratio of dodecanoic acid to water in the first mixture is 1:2 by mass; slowly adding a second mixture to the first mixture; carrying out a salt formation reaction at 90°C for 3 h; raising the temperature to T1°C under a protective atmosphere (nitrogen); adding a catalyst (potassium phosphite) and an antioxidant (antioxidant 168); carrying out a pre-condensation reaction for 2 h; and then raising the temperature to T2°C for a vacuum condensation reaction for 5 h (the vacuum degree during the vacuum condensation reaction is ≤200P). (a) Cool to room temperature, granulate, and obtain long-chain transparent nylon. The second mixture is a mixture of 1,6-hexanediamine, 2,6-naphthalenedicarboxylic acid, and water. By mass, the ratio of the sum of 1,6-hexanediamine and 2,6-naphthalenedicarboxylic acid to water in the second mixture is 1:2. By molar amount, the ratio of dodecanoic acid, 1,6-hexanediamine, and 2,6-naphthalenedicarboxylic acid is 100:200:100. By mass, the ratio of dodecanoic acid, catalyst, and antioxidant is 1:0.005:0.005. T1 = 190, T2 = 250.

[0082] The structural formula of the obtained long-chain transparent nylon is as follows:

[0083] ,

[0084] Where m∶n=1∶1.

[0085] Comparative Example 4

[0086] A method for preparing long-chain transparent nylon is basically the same as that in Comparative Example 3, except that "2,6-naphthalenedicarboxylic acid" is replaced with "1,4-cyclohexanediethanol". The ratio of dodecanoic acid, 1,6-hexanediamine, and 1,4-cyclohexanediethanol, by molar amount, is 200:100:100. The structural formula of the resulting long-chain transparent nylon is as follows:

[0087] ,

[0088] Where m∶n=1∶1.

[0089] Comparative Example 5

[0090] A method for preparing a long-chain transparent nylon (PAPACM12) is basically the same as that in Comparative Example 1, except that "1,6-hexanediamine" is replaced with "4,4'-diaminodicyclohexylmethane". The mass ratio of dodecanoic acid, 4,4'-diaminodicyclohexylmethane, and water is 200:200:176, where the mass fraction is expressed in mol and the weight fraction in kg. The structural formula of the obtained long-chain transparent nylon (PAPACM12) is as follows:

[0091] .

[0092] The long-chain transparent nylons based on PACM copolymerization modification in Examples 1-6, the long-chain nylons in Comparative Examples 1-2, and the long-chain transparent nylons in Comparative Examples 3-5 were used as polymers. The polymers were dissolved in sulfuric acid (with a H2SO4 concentration of 18 mol / L) at (25±0.01) °C to prepare polymer solutions with a polymer concentration of 1 mg / dL. The intrinsic viscosity of the polymer solutions was measured using an Ubbelohde viscometer, and the results are shown in Table 1.

[0093] The polymer was molded into dumbbell-shaped specimens with dimensions of 75.0 mm × 5.0 mm × 2.0 mm using an injection molding machine. The yield strength, breaking strength and elongation at break of the dumbbell-shaped specimens were tested according to the method of standard ISO527-1:2019. The results are shown in Table 1.

[0094] The polymer was molded into rectangular strips of 80.0mm×10.0mm×4.0mm using an injection molding machine. The flexural strength and flexural modulus of the rectangular strips were tested according to the method of standard ISO178:2019. The results are shown in Table 1.

[0095] The polymer was melted at 260°C and extruded using a single-screw extruder to obtain polymer sheets with a thickness of approximately 0.50 mm. These sheets were then cut into 100 mm × 100 mm samples, held at 130°C for 2 min, and subjected to a progressive biaxial stretching process: first, the samples were stretched at 130°C along the machine direction (MD) at approximately 50%·s. -1 The sample was stretched at a stretching rate to 2.5 times its initial width (100 mm); then heated to 140 °C, and stretched at the same stretching rate along the transverse direction (TD, perpendicular to the machine direction) to 4.0 times its initial length (100 mm). The total stretching ratio in the MD and TD directions was approximately 2.5 × 4.0 ≈ 10, resulting in a film with a thickness of approximately 50 μm. Through a stepwise biaxial stretching process, the polymer's bidirectional segment orientation was achieved, yielding a film with the target thickness (50 μm). After stretching, while maintaining the MD and TD dimensions, the film was heat-set at 150 °C for 60 s to stabilize the bidirectional orientation structure and reduce subsequent thermal shrinkage. After heat setting, circulating cold air was turned on, and the film was cooled to 40 °C at a cooling rate of approximately 20 °C / min, and then naturally cooled from 40 °C to room temperature, finally obtaining a biaxially oriented film with a thickness of approximately 50 μm. The transmittance of the biaxially oriented thin film was measured using a UH4150 UV-Vis spectrometer. The results are shown in Table 1 and... Figure 1 As shown in Table 1, the transmittance is the transmittance at a wavelength of 550 nm. The haze of the biaxially oriented film was tested according to the method of ASTM D1003, and the roughness of the biaxially oriented film was tested according to the method of GB / T 31227-2014. The results are shown in Table 1.

[0096] Table 1

[0097]

[0098] As shown in Table 1, the introduction of different proportions of PACM into the long-chain transparent nylon (PA612 / PACM12) based on PACM copolymerization modification in Examples 1 and 4-6 enhanced the mechanical properties of PA612 to a certain extent, and improved the optical properties (transmittance and haze) and roughness of the prepared biaxially oriented films to varying degrees. Compared with the uncopolymerized PA612 in Comparative Example 1, the PA612 / PACM12 in Examples 1 and 4-6 had higher elongation at break, i.e., higher toughness, and the prepared biaxially oriented films had higher transmittance, lower haze, and smaller roughness. Although the biaxially oriented film prepared from PA612 / PACM12 in Example 2 showed improvements in transmittance, haze, and roughness compared to the biaxially oriented film prepared from PA612 in Comparative Example 1, the effect was still inferior to that of the biaxially oriented film in Example 1, indicating that antioxidant 168 was more preferred. In Example 3, the PA612 / PACM12 did not achieve the purpose of copolymerization modification because the salt formation reaction time was too short and the groups did not react fully.

[0099] Comparative Example 2, PA1012 prepared using the same method, exhibited poor mechanical properties and appearance. Comparative Examples 3 and 4 introduced 2,6-naphthalenedicarboxylic acid and 1,4-cyclohexanediethanol, respectively, to copolymerize and modify PA612. Although the toughness and transmittance of the prepared biaxially oriented film improved somewhat, the effect was unsatisfactory. This polymer exhibited some phase separation, resulting in poor mechanical properties and high roughness of the biaxially oriented film. Comparative Example 5, a homopolymer of PA and PACM12, while possessing high elongation at break and flexural strength, exhibited poor yield strength and tensile strength, relatively high haze, and lower transmittance than Examples 5 and 6.

[0100] The polymers from Examples 1, 4-6, Comparative Examples 1, and 3-5 were used as samples. Differential scanning calorimetry (DSC) was used to analyze the thermal properties and crystallization ability of each sample: Under a nitrogen atmosphere, 5 mg of sample was placed in a sample cell and heated to 280°C at a rate of 10°C / min, held at that temperature for 5 min to eliminate thermal history; then cooled from 280°C to 25°C at a rate of 10°C / min, held at that temperature for 5 min, and the cooling curve was recorded. Figure 2 As shown in b; then increase the temperature to 280℃ at a rate of 10℃ / min, and record the heating curve, as shown in Figure b. Figure 2 As shown in a. From Figure 2 It can be seen that, compared with PA612 in Comparative Example 1, the crystallization temperature (T) of the PA612 / PACM12 polymers in Examples 1 and 4-6 is relatively high. c ) and melting point (T mThe concentrations of PA612 and PACM12 were all relatively low, and gradually decreased with increasing PACM12 segment content in the molecular chain. This phenomenon is attributed to the fact that the PACM12 segment itself has a bicyclic structure with significant steric hindrance. The introduction of the PACM12 segment disrupts the regularity of the PA612 molecular chain, weakens the intermolecular hydrogen bonding forces, and thus makes the polymer crystal structure irregular. At the same time, the weakening of hydrogen bonding forces also effectively reduces its crystallization rate. In Example 5, the PA612 / PACM12 showed a cold crystallization peak in the second heating curve. This is because its highly disordered molecular chain structure leads to an incomplete crystal structure. When the temperature rises above the glass transition temperature, its molecular chain rearranges, resulting in a cold crystallization peak. In Example 6, no crystallization peak or melting peak was observed in the DSC curve of PA612 / PACM12, indicating that the introduction of PACM successfully disrupted the crystal structure of PA612, making the polymer completely amorphous.

[0101] The nuclear magnetic resonance (NMR) spectrometer was a Bruker AVIII 400 1H NMR spectrometer. 1 1H NMR (1H NMR) spectra of the polymers in Examples 1, 4-6, and Comparative Example 1 were tested (the solvent used for acquiring the 1H NMR spectra was CF3COOD). The results are as follows: Figure 3 As shown. By Figure 3 It can be seen that the multiplets at 4.14 ppm and 4.26 ppm are attributed to the protons connecting the two cyclohexyl ring methylene groups, the multiplet at 4.37 ppm is attributed to the protons on the methylene groups connected to the cyclohexyl and amino groups, and the quartet at 4.54 ppm corresponds to the protons on the methylene groups of the aliphatic ring. The chemical shift peaks on the proton spectrum correspond to the structure of the polymer, confirming the successful synthesis of polymer PA612 / PACM12.

[0102] When antioxidant 1010 is used, the same technical effect as antioxidant 168 can be achieved.

[0103] The present invention has been described above by way of example. It should be noted that any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort without departing from the core of the present invention fall within the protection scope of the present invention.

Claims

1. A long carbon chain transparent nylon based on PACM copolymerization modification, characterized in that, It has the following structural formula: wherein m:n = (1-4):(6-9).

2. A method for producing a long carbon chain transparent nylon based on PACM copolymerization modification, characterized by, Comprise: The dodecanedioic acid and water are mixed uniformly to obtain a first mixture, a second mixture is added to the first mixture, a salting reaction is carried out for 2-5 hours, after the salting reaction is completed, the temperature is raised to 190-230 DEG C under a protective atmosphere, a catalyst and an antioxidant are added for a pre-polycondensation reaction, after the pre-polycondensation reaction is completed, the temperature is raised to 250-270 DEG C for a vacuum polycondensation reaction, cooled to room temperature, granulated, to obtain a long carbon chain transparent nylon based on PACM copolymerization modification; The second mixture is a mixture of 1,6-hexanediamine, 4,4'-diaminodicyclohexyl methane and water, the ratio of the sum of 1,6-hexanediamine and 4,4'-diaminodicyclohexyl methane to water in the second mixture is 1: (2-3) by mass fraction; The ratio of dodecanedioic acid, 1,6-hexanediamine and 4,4'-diaminodicyclohexyl methane is 200: (120-180): (20-80) by mole fraction. The antioxidant is a mixture of one or more of antioxidant 168 and antioxidant 1010.

3. The preparation method according to claim 2, characterized in that, The ratio of dodecanedioic acid to water in the first mixture is 1: (2-3) by mass fraction.

4. The preparation method according to claim 2, characterized in that, The uniform mixing includes stirring at 60-90 DEG C for 15-30 minutes.

5. The preparation method according to claim 2, characterized in that, The temperature of the salting reaction is 70-90 DEG C.

6. The preparation method according to claim 2, characterized in that, The time of the pre-polycondensation reaction is 2-4 hours.

7. The preparation method according to claim 2, characterized in that, The time of the vacuum polycondensation reaction is 3-5 hours, and the vacuum degree during the vacuum polycondensation reaction is ≤200 Pa.

8. The preparation method according to claim 2, characterized in that, The catalyst is a mixture of one or more of potassium phosphite, sodium phosphite, magnesium phosphite, potassium hypophosphite, sodium hypophosphite and magnesium hypophosphite.

9. The preparation method according to claim 2, characterized in that, The ratio of dodecanedioic acid, catalyst and antioxidant is 1: (0.001-0.005): (0.001-0.005) by mass fraction.

10. The use of the long carbon chain transparent nylon according to claim 1 to improve light transmittance, toughness, wear resistance, dimensional stability or mechanical properties.

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