Hydrophobic high-strength transparent nylon as well as preparation method and application thereof

Abstract

The invention relates to the technical field of nylon materials, in particular to hydrophobic high-strength transparent nylon as well as a preparation method and application thereof. According to the preparation method, 3, 3 '-dimethyl-4, 4-diaminodicyclohexylmethane (MACM), aromatic diamine and fatty diacid are taken as reaction monomers, and the novel transparent nylon is obtained by adjusting the dosage ratio of the monomers and further adjusting the preparation process (regulating and controlling the reaction process). The transparent nylon provided by the invention has the advantages of hydrophobicity, high strength and high light transmittance. The technical problem that existing nylon is high in water absorption rate is solved. The hydrophobic transparent nylon provided by the invention can be used under the condition of high humidity, and has higher safety and longer service life; therefore, the application field of the transparent nylon is expanded.

Description

Technical Field

[0001] The present invention relates to the technical field of nylon materials, and more particularly to a hydrophobic high-strength transparent nylon and a preparation method and application thereof. Background Art

[0002] Since its industrial production began in the 1930s, nylon (also known as polyamide (PA)) has established itself as a key engineering plastic due to its exceptional mechanical strength, wear resistance, chemical resistance, and self-lubricity. It is widely used in automobiles, electronic appliances, industrial machinery, sports equipment, and everyday items. Traditional nylon (such as PA6 and PA66) has a regular molecular chain structure and is prone to forming crystalline regions. This gives the material a translucent or opaque milky white appearance, limiting its use in applications requiring visual clarity, such as observation windows, fluid containers, or transparent housing components. To overcome this optical limitation, transparent nylon was developed.

[0003] Transparent nylon is not a single material, but a type of polyamide variant that achieves high transparency through sophisticated molecular structure design. The core strategy for achieving transparency focuses on regulating crystallization behavior: first, by introducing bulky side groups (such as methyl) or asymmetric monomers (such as isophthalic acid) for copolymerization modification, the regularity of the molecular chain is destroyed and the formation of large-sized crystals is inhibited; second, aliphatic long-chain monomers (such as PA12 monomer) are used to reduce the density of amide groups and hydrogen bonding forces, prompting them to form an amorphous structure; third, specific nucleating agents are used to control crystal growth to the nanoscale (smaller than the wavelength of visible light) to avoid light scattering, which is common in semi-aromatic nylons (such as PA6I / 6T, PA MACM12). These technical paths enable transparent nylon to achieve a transmittance of more than 90%, and its transparency is comparable to traditional transparent plastics such as polycarbonate (PC) and polymethyl methacrylate (PMMA).

[0004] However, because the amide groups (-CONH-) in nylon molecules are hydrophilic, nylon has a strong affinity for water. Furthermore, the greater the density of amide bonds, the higher its water absorption rate. For example, at a temperature of 23°C and a relative humidity of 50%, the equilibrium water absorption rate of existing PA6 is approximately 2.5%. At a relative humidity of 100%, the equilibrium water absorption rate rises to 9%. When nylon absorbs water, its physical and mechanical properties are affected, reducing the safety and service life of nylon products. Summary of the Invention

[0005] In order to solve the technical problem of high water absorption of existing nylon, the present invention provides a hydrophobic high-strength transparent nylon and a preparation method and application thereof.

[0006] This invention utilizes 3,3'-dimethyl-4,4-diaminodicyclohexylmethane (MACM), aromatic diamines, and fatty diacids as reactive monomers. By adjusting the ratio of the monomers and further adjusting the preparation process (controlling the reaction process), a new transparent nylon is obtained. The transparent nylon provided by this invention exhibits hydrophobicity, high strength, and high light transmittance.

[0007] One of the objects of the present invention is to provide a hydrophobic transparent nylon.

[0008] The hydrophobic transparent nylon comprises a polymer as shown in Formula I;

[0009]

[0010] In Formula I,

[0011] m is any integer between 500 and 5000;

[0012] n is any integer between 500 and 5000;

[0013] p is any integer from 1 to 12;

[0014] The NH group on the benzene ring is located at the 3- or 4-position of the benzene ring.

[0015] The formula I can specifically be:

[0016]

[0017]

[0018] One of, but not limited to.

[0019] The compound of formula I in the hydrophobic transparent nylon comprises a structural unit A derived from MACM Structural unit B derived from aromatic diamine and structural units C derived from fatty diacids

[0020] The hydrophobic transparent nylon has two methyl groups on the dicyclohexylmethane ring of structural unit A, and one methyl group on the benzene ring of structural unit B. The methyl groups on structural unit A and structural unit B have a significant steric hindrance effect, hindering the close stacking of molecular chains, making it difficult to form a regular lattice structure, preventing excessive crystallization, and improving the light transmittance of the nylon.

[0021] Structural unit C of the hydrophobic transparent nylon contains a methylene chain. The flexibility of the methylene chain improves the toughness of the nylon material and broadens the downstream applications of transparent nylon. The methylene chain of structural unit C also synergizes with the methyl groups on structural units A and B to reduce the density of amide bonds, thereby increasing the hydrophobicity of the nylon and reducing its water and hygroscopicity.

[0022] The hydrophobic transparent nylon further comprises a hydrophobic agent.

[0023] The hydrophobic agent added to the hydrophobic transparent nylon can serve as a physical barrier to the molecular chain, occupying space, reducing the total volume ratio of the amide group, making it difficult for water molecules to penetrate and form hydrogen bonds, and can also effectively extend the diffusion path of water molecules in the nylon material, increase the diffusion resistance of water molecules, reduce the water absorption rate of the nylon material, and reduce the equilibrium water absorption rate of the nylon material.

[0024] The hydrophobic transparent nylon is prepared from raw materials including 3,3'-dimethyl-4,4-diaminodicyclohexylmethane, aromatic diamine, fatty diacid and a hydrophobic agent.

[0025] A second object of the present invention is to provide a method for preparing the hydrophobic transparent nylon described in the first object of the invention.

[0026] The preparation method comprises:

[0027] (1) mixing 3,3'-dimethyl-4,4-diaminodicyclohexylmethane (MACM), aromatic diamine, fatty diacid, catalyst, antioxidant, light stabilizer, hydrophobic agent and deionized water to obtain a mixed material;

[0028] (2) Under an inert atmosphere, the mixed material is subjected to a condensation reaction.

[0029] The product of the condensation reaction in step (2) is the hydrophobic transparent nylon. After step (2) is completed, in addition to the product hydrophobic transparent nylon, there are impurities (such as unreacted monomers) in the system; impurities are usually removed by water washing to obtain the hydrophobic transparent nylon. The water washing adopts a conventional water washing method.

[0030] The aromatic diamine is selected from methyl-phenylenediamine, preferably at least one selected from 2-methyl-1,4-phenylenediamine and 2-methyl-1,3-phenylenediamine.

[0031] The fatty diacid is selected from the straight-chain fatty diacid of C3-C14, preferably at least one of malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, 1,10-decanedioic acid, 1,11-undecanoic acid, 1,12-dodecanoic acid, 1,13-tridecanoic acid and 1,14-tetradecanoic acid. Compared with the straight-chain fatty diacid of other C11-C14, the hydrophobic transparent nylon prepared by adopting malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid has significantly improved thermodynamic properties, processing performance (lower processing temperature, easier to evaporate, etc.) promotion, modulus and strength greatly improve. Therefore, as a preferred embodiment, the fatty diacid is selected from one or more of malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid.

[0032] The catalyst can be selected from any one or more existing catalysts used for synthesizing polyamides. As a preferred embodiment, the catalyst is selected from at least one of N,N-dimethylcyclohexylamine, bis(2-dimethylaminoethyl) ether, N,N,N',N'-tetramethylalkylenediamine, triethylamine, N,N-dimethylbenzylamine, solid amine, N-ethylmorpholine, N-methylmorpholine, N,N-diethylpiperazine, potassium phosphate, sodium phosphate, potassium hypophosphite, sodium hypophosphite, potassium phosphite, sodium phosphite, potassium hypophosphite, sodium hypophosphite, n-butyl titanate, propyl titanate, and isopropyl titanate.

[0033] The antioxidant can be selected from any one or more existing antioxidants used in the synthesis of polyamide. Specifically, the antioxidant is selected from at least one of pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyhydrocinnamate) (Antioxidant 1010), β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (Antioxidant 1076), N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexanediamine (Antioxidant 1098), tris(2,4-di-tert-butyl)phenyl phosphite (Antioxidant 168), potassium iodide, and a copper salt. The copper salt can be selected from at least one of copper iodide, cuprous iodide, copper acetate, copper carbonate, copper oxide, and cuprous oxide.

[0034] The light stabilizer can be selected from any one or more existing light stabilizers used for synthesizing polyamide. As a specific solution, the light stabilizer is selected from at least one of UV-3346, UV-123, UV-292, UV-622, UV-770DF, UV-944, UV-2020, and UV-660.

[0035] The hydrophobic agent can be selected from any one or more existing hydrophobic agents used for synthesizing polyamide. As a specific embodiment, the hydrophobic agent is selected from at least one of glass fiber, carbon fiber, talc, mica, silica, polyolefin (PE), polyphenylene ether (PPO), polyphenylene sulfide (PPS), and polytetrafluoroethylene (PTFE).

[0036] The molar ratio of the total amount of the aromatic diamine and 3,3'-dimethyl-4,4-diaminodicyclohexylmethane (MACM) to the fatty diacid determines the molar ratio of the total amount of the structural units derived from the aromatic diamine and the structural units derived from MACM to the structural units derived from the fatty diacid in the transparent nylon. In the hydrophobic transparent nylon, the molar ratio of the total amount of the structural units derived from the aromatic diamine and the structural units derived from MACM to the structural units derived from the fatty diacid is 1:1. Therefore, the ratio of the total molar amount of the aromatic diamine and 3,3'-dimethyl-4,4-diaminodicyclohexylmethane (MACM) to the molar amount of the fatty diacid is about 1:1, for example (0.8 to 1.5):1, preferably (1 to 1.5):1.

[0037] The molar ratio of the aromatic diamine to 3,3'-dimethyl-4,4-diaminodicyclohexylmethane (MACM) determines the molar ratio of the structural units derived from the aromatic diamine to the structural units derived from MACM in the transparent nylon. The molar ratio of the structural units derived from the aromatic diamine to the structural units derived from MACM in the transparent nylon is n:m, i.e., (500-5000):(500-5000), preferably 1:(0.6-1.4), and more preferably 1:(0.8-1.2). Therefore, the molar ratio of the aromatic diamine to 3,3'-dimethyl-4,4-diaminodicyclohexylmethane (MACM) is m:n, preferably 1:(0.6-1.4), and more preferably 1:(0.8-1.2).

[0038] As a preferred embodiment, the molar ratio of the fatty diacid to the aromatic diamine is 2:(0.6-1.4), preferably 2:(0.8-1.2).

[0039] The catalyst can be used in a conventional amount. As a preferred embodiment, the catalyst is added in an amount of 0.05% to 0.30% of the total mass of the fatty diacid, aromatic diamine and 3,3'-dimethyl-4,4-diaminodicyclohexylmethane, preferably 0.10% to 0.25%.

[0040] The amount of the antioxidant can be a conventional amount. As a preferred embodiment, the amount of the antioxidant added is 0.1% to 1.0% of the total mass of the fatty diacid, aromatic diamine and 3,3'-dimethyl-4,4-diaminodicyclohexylmethane, preferably 0.10% to 0.8%.

[0041] The amount of the light stabilizer can be a conventional amount. As a preferred embodiment, the amount of the light stabilizer added is 0.08% to 0.20% of the total mass of the fatty diacid, aromatic diamine and 3,3'-dimethyl-4,4-diaminodicyclohexylmethane, preferably 0.11% to 0.15%.

[0042] The amount of the hydrophobic agent can be a conventional amount. As a preferred embodiment, the amount of the hydrophobic agent added is 0.5% to 5.0% of the total mass of the fatty diacid, aromatic diamine and 3,3'-dimethyl-4,4-diaminodicyclohexylmethane, preferably 0.80% to 4.5%.

[0043] The amount of deionized water used can be a conventional amount. As a preferred embodiment, the amount of deionized water added is 35% to 65% of the total mass of the fatty diacid, phenylenediamine and 3,3'-dimethyl-4,4-diaminodicyclohexylmethane, preferably 40% to 60%.

[0044] The control of the reaction process and reaction conditions of the condensation reaction in step (2) of the preparation method is the key to synthesizing the transparent nylon, which is one of the purposes of the invention. The present invention adjusts the reaction temperature and pressure so that the condensation reaction is carried out in three stages.

[0045] The condensation reaction in step (2) of the preparation method includes a first stage reaction, a second stage reaction and a third stage reaction carried out in sequence:

[0046] The first stage reaction conditions are: 255-300°C, 2.5-3 MPa, reaction time 3.0-3.5 hours;

[0047] The reaction conditions for the second stage are: 310-320°C, 0.3-0.4 MPa, reaction time 2.2-2.5 hours;

[0048] The reaction conditions for the third stage are: room temperature and normal pressure for 1 to 1.5 hours.

[0049] As a preferred option:

[0050] The first stage reaction conditions are: 260-290℃, 2.6-3MPa, reaction time 3-3.2h,

[0051] The second stage reaction conditions are: 310-315℃, 0.3-0.35MPa, reaction time 2.2-2.4h,

[0052] The reaction conditions for the third stage are: room temperature and normal pressure for 1 to 1.3 hours.

[0053] The condensation reaction is carried out under stirring conditions, and the stirring speed is 300-500 r / min.

[0054] The inert atmosphere is a nitrogen atmosphere.

[0055] As a specific solution, the preparation method includes:

[0056] (1) adding fatty diacid, aromatic diamine, 3,3'-dimethyl-4,4-diaminodicyclohexylmethane, catalyst, antioxidant, light stabilizer, hydrophobic agent and deionized water to a magnetically driven high-pressure reactor according to the amounts described, and replacing the air in the reactor with nitrogen;

[0057] (2) Raise the temperature of the reactor to 255-300°C, introduce nitrogen until the system is at 2.5-3 MPa, and react for 3.0-3.5 hours;

[0058] (3) reducing the pressure to 0.3-0.4 MPa and raising the temperature of the reactor to 310-320° C. for 2.2-2.5 hours;

[0059] (4) Cooling to room temperature, reducing pressure to normal pressure and continuing the reaction for 1 to 1.5 hours;

[0060] (5) washing with water to obtain the hydrophobic high-strength transparent nylon;

[0061] Steps (2), (3) and (4) are carried out at a stirring speed of 300 to 500 r / min.

[0062] A third object of the present invention is to provide applications of the hydrophobic transparent nylon described in the first object of the invention or the hydrophobic transparent nylon prepared by the preparation method described in the second object of the invention in the fields of food and beverage packaging, medical devices, precision instruments, optical instruments, electronic appliances, automobile manufacturing, machinery, aviation, sporting goods, etc.

[0063] Compared with the prior art, the present invention has the following beneficial effects:

[0064] The nylon material described in the present invention is semi-aromatic nylon. Because its molecular structure contains both rigid benzene rings and flexible methylene chains, it can balance the relationship between the mechanical properties and optical properties of the material, so that it has both the excellent light transmittance of aliphatic nylon and the high strength of fully aromatic nylon.

[0065] The hydrophobic transparent nylon provided by the present invention has low water absorption and hygroscopicity and excellent hydrophobicity. The hydrophobic transparent nylon provided by the present invention has excellent hydrophobicity and high mechanical properties while maintaining a certain degree of transparency and high optical properties.

[0066] The hydrophobic transparent nylon provided by the present invention can be used under conditions of high humidity and has higher safety and service life, thereby expanding the application field of transparent nylon.

[0067] Unless otherwise specified, the room temperature in the present invention is 10-30°C. DETAILED DESCRIPTION

[0068] The present invention will be described in detail below with reference to specific embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art to the present invention based on the contents of the present invention still fall within the scope of protection of the present invention.

[0069] Unless otherwise specified, the raw materials used in the Examples and Comparative Examples are publicly available in the prior art and can be purchased directly or prepared according to methods disclosed in the prior art. The solvents used in the Examples and Comparative Examples were purchased from Shanghai MacLean Biochemical Technology Co., Ltd., and all reaction raw materials were purchased from Alfa Aesar.

[0070] Example 1

[0071] A method for preparing hydrophobic high-strength transparent nylon, the method comprising the following steps:

[0072] (1) 25 parts of malonic acid, 14.7 parts of 2-methyl-1,4-phenylenediamine, 28.7 parts of MACM, 0.07 parts of sodium hypophosphite, 0.07 parts of potassium iodide, 0.10 parts of UV-3346, 0.55 parts of glass fiber and 27.4 parts of deionized water were added to a magnetically driven high-pressure reactor, and then nitrogen was introduced to replace the air in the reactor.

[0073] (2) Set the stirring speed to 350 r / min, raise the reactor temperature to 255°C, introduce nitrogen until the system pressure reaches 2.5 MPa, and react for 3.0 h;

[0074] (3) reducing the pressure to 0.3 MPa and raising the reactor temperature to 310°C for 2.2 h;

[0075] (4) Cool to room temperature, reduce pressure to normal pressure and continue the reaction for 1 hour.

[0076] (5) washing with water and discharging the product to obtain the hydrophobic high-strength transparent nylon.

[0077] Example 2

[0078] A method for preparing hydrophobic high-strength transparent nylon, the method comprising the following steps:

[0079] (1) 25 parts of succinic acid, 15.2 parts of 2-methyl-1,4-phenylenediamine, 29.3 parts of MACM, 0.08 parts of sodium hypophosphite, 0.08 parts of potassium iodide, 0.09 parts of UV-3346, 0.65 parts of talc, and 27.8 parts of deionized water were added to a magnetically driven high-pressure reactor, and then nitrogen was introduced to replace the air in the reactor.

[0080] (2) Set the stirring speed to 350 r / min, raise the reactor temperature to 255°C, introduce nitrogen until the system pressure reaches 2.5 MPa, and react for 3.0 h;

[0081] (3) reducing the pressure to 0.3 MPa and raising the reactor temperature to 310°C for 2.2 h;

[0082] (4) Cool to room temperature, reduce pressure to normal pressure and continue the reaction for 1 hour.

[0083] (5) washing with water and discharging the product to obtain the hydrophobic high-strength transparent nylon.

[0084] Example 3

[0085] A method for preparing hydrophobic high-strength transparent nylon, the method comprising the following steps:

[0086] (1) 25 parts of glutaric acid, 15.9 parts of 2-methyl-1,4-phenylenediamine, 29.7 parts of MACM, 0.08 parts of sodium hypophosphite, 0.08 parts of potassium iodide, 0.11 parts of UV-123, 0.55 parts of carbon fiber and 28.4 parts of deionized water were added to a magnetically driven high-pressure reactor, and then nitrogen was introduced to replace the air in the reactor;

[0087] (2) Set the stirring speed to 350 r / min, raise the reactor temperature to 255°C, introduce nitrogen until the system pressure reaches 2.5 MPa, and react for 3.0 h;

[0088] (3) reducing the pressure to 0.3 MPa and raising the reactor temperature to 310°C for 2.2 h;

[0089] (4) Cool to room temperature, reduce pressure to normal pressure and continue the reaction for 1 hour.

[0090] (5) washing with water and discharging the product to obtain the hydrophobic high-strength transparent nylon.

[0091] Example 4

[0092] A method for preparing hydrophobic high-strength transparent nylon, the method comprising the following steps:

[0093] (1) 25 parts of adipic acid, 16.4 parts of 2-methyl-1,4-phenylenediamine, 30.4 parts of MACM, 0.09 parts of sodium hypophosphite, 0.10 parts of potassium iodide, 0.12 parts of UV-292, 0.56 parts of mica, and 28.9 parts of deionized water were added to a magnetically driven high-pressure reactor, and then nitrogen was introduced to replace the air in the reactor.

[0094] (2) Set the stirring speed to 350 r / min, raise the reactor temperature to 255°C, introduce nitrogen until the system pressure reaches 2.5 MPa, and react for 3.0 h;

[0095] (3) reducing the pressure to 0.3 MPa and raising the reactor temperature to 310°C for 2.2 h;

[0096] (4) Cool to room temperature, reduce pressure to normal pressure and continue the reaction for 1 hour.

[0097] (5) washing with water and discharging the product to obtain the hydrophobic high-strength transparent nylon.

[0098] Example 5

[0099] A method for preparing hydrophobic high-strength transparent nylon, the method comprising the following steps:

[0100] (1) After adding 25 parts of pimelic acid, 16.7 parts of 2-methyl-1,3-phenylenediamine, 30.9 parts of MACM, 0.10 parts of sodium hypophosphite, 0.11 parts of potassium iodide, 0.15 parts of UV-622, 0.58 parts of silicon dioxide and 29.5 parts of deionized water into a magnetically driven high-pressure reactor according to parts by weight, nitrogen was introduced to replace the air in the reactor;

[0101] (2) Set the stirring speed to 350 r / min, raise the reactor temperature to 255°C, introduce nitrogen until the system pressure reaches 2.5 MPa, and react for 3.0 h;

[0102] (3) reducing the pressure to 0.3 MPa and raising the reactor temperature to 310°C for 2.2 h;

[0103] (4) Cool to room temperature, reduce pressure to normal pressure and continue the reaction for 1 hour.

[0104] (5) washing with water and discharging the product to obtain the hydrophobic high-strength transparent nylon.

[0105] Example 6

[0106] A method for preparing hydrophobic high-strength transparent nylon, the method comprising the following steps:

[0107] (1) 25 parts of suberic acid, 17.5 parts of 2-methyl-1,3-phenylenediamine, 31.6 parts of MACM, 0.10 parts of sodium hypophosphite, 0.11 parts of potassium iodide, 0.15 parts of UV-622, 0.59 parts of polyolefin (PE) and 30.3 parts of deionized water were added to a magnetically driven high-pressure reactor, and then nitrogen was introduced to replace the air in the reactor;

[0108] (2) Set the stirring speed to 350 r / min, raise the reactor temperature to 255°C, introduce nitrogen until the system pressure reaches 2.5 MPa, and react for 3.0 h;

[0109] (3) reducing the pressure to 0.3 MPa and raising the reactor temperature to 310°C for 2.2 h;

[0110] (4) Cool to room temperature, reduce pressure to normal pressure and continue the reaction for 1 hour.

[0111] (5) washing with water and discharging the product to obtain the hydrophobic high-strength transparent nylon.

[0112] Example 7

[0113] A method for preparing hydrophobic high-strength transparent nylon, the method comprising the following steps:

[0114] (1) 25 parts of azelaic acid, 18.2 parts of 2-methyl-1,3-phenylenediamine, 31.6 parts of MACM, 0.10 parts of sodium hypophosphite, 0.11 parts of potassium iodide, 0.18 parts of UV-770DF, 0.62 parts of polyphenylene ether (PPO), and 34.8 parts of deionized water were added to a magnetically driven high-pressure reactor according to weight parts, and then nitrogen was introduced to replace the air in the reactor;

[0115] (2) Set the stirring speed to 350 r / min, raise the reactor temperature to 255°C, introduce nitrogen until the system pressure reaches 2.5 MPa, and react for 3.0 h;

[0116] (3) reducing the pressure to 0.3 MPa and raising the reactor temperature to 310°C for 2.2 h;

[0117] (4) Cool to room temperature, reduce pressure to normal pressure and continue the reaction for 1 hour.

[0118] (5) washing with water and discharging the product to obtain the hydrophobic high-strength transparent nylon.

[0119] Example 8

[0120] A method for preparing hydrophobic high-strength transparent nylon, the method comprising the following steps:

[0121] (1) 25 parts of sebacic acid, 18.5 parts of 2-methyl-1,3-phenylenediamine, 31.9 parts of MACM, 0.10 parts of sodium hypophosphite, 0.11 parts of potassium iodide, 0.20 parts of UV-944, 0.62 parts of polyphenylene sulfide (PPS) and 36.5 parts of deionized water were added to a magnetically driven high-pressure reactor according to weight parts, and then nitrogen was introduced to replace the air in the reactor;

[0122] (2) Set the stirring speed to 350 r / min, raise the reactor temperature to 255°C, introduce nitrogen until the system pressure reaches 2.5 MPa, and react for 3.0 h;

[0123] (3) reducing the pressure to 0.3 MPa and raising the reactor temperature to 310°C for 2.2 h;

[0124] (4) Cool to room temperature, reduce pressure to normal pressure and continue the reaction for 1 hour.

[0125] (5) washing with water and discharging the product to obtain the hydrophobic high-strength transparent nylon.

[0126] Comparative Example 1

[0127] A method for preparing nylon, comprising the following steps:

[0128] (1) 25 parts of malonic acid, 14.7 parts of 2-methyl-1,4-phenylenediamine, 28.7 parts of MACM, 0.07 parts of sodium hypophosphite, 0.07 parts of potassium iodide, 0.10 parts of UV-3346, 0.55 parts of glass fiber and 27.4 parts of deionized water were added to a magnetically driven high-pressure reactor, and then nitrogen was introduced to replace the air in the reactor.

[0129] (2) Set the stirring speed to 350 r / min, raise the reactor temperature to 200°C, introduce nitrogen until the system pressure reaches 1.5 MPa, and react for 2.5 h;

[0130] (3) reducing the pressure to 0.25 MPa and raising the reactor temperature to 250°C for 2 h;

[0131] (4) Cool to room temperature, reduce pressure to normal pressure and continue the reaction for 1 hour.

[0132] (5) washing with water and discharging the product to obtain the hydrophobic high-strength transparent nylon.

[0133] Comparative Example 2

[0134] A method for preparing nylon, comprising the following steps:

[0135] (1) 25 parts of malonic acid, 5.3 parts of 2-methyl-1,4-phenylenediamine, 18.4 parts of MACM, 0.07 parts of sodium hypophosphite, 0.07 parts of potassium iodide, 0.10 parts of UV-3346, 0.55 parts of glass fiber and 27.4 parts of deionized water were added to a magnetically driven high-pressure reactor, and then nitrogen was introduced to replace the air in the reactor.

[0136] (2) Set the stirring speed to 350 r / min, raise the reactor temperature to 255°C, introduce nitrogen until the system pressure reaches 2.5 MPa, and react for 3.0 h;

[0137] (3) reducing the pressure to 0.3 MPa and raising the reactor temperature to 310°C for 2.2 h;

[0138] (4) Cool to room temperature, reduce pressure to normal pressure and continue the reaction for 1 hour.

[0139] (5) washing with water and discharging the product to obtain the hydrophobic high-strength transparent nylon.

[0140] Comparative Example 3

[0141] A method for preparing nylon, comprising the following steps:

[0142] (1) 25 parts of malonic acid, 14.7 parts of 2-methyl-1,4-phenylenediamine, 0.07 parts of sodium hypophosphite, 0.07 parts of potassium iodide, 0.10 parts of UV-3346, 0.55 parts of glass fiber, and 27.4 parts of deionized water were added to a magnetically driven high-pressure reactor, and then nitrogen was introduced to replace the air in the reactor.

[0143] (2) Set the stirring speed to 350 r / min, raise the reactor temperature to 255°C, introduce nitrogen until the system pressure reaches 2.5 MPa, and react for 3.0 h;

[0144] (3) reducing the pressure to 0.3 MPa and raising the reactor temperature to 310°C for 2.2 h;

[0145] (4) Cool to room temperature, reduce pressure to normal pressure and continue the reaction for 1 hour.

[0146] (5) washing with water and discharging the product to obtain the hydrophobic high-strength transparent nylon.

[0147] Experimental example

[0148] The hydrophobic, high-strength transparent nylon prepared in Examples 1 to 8 and the nylon prepared in Comparative Examples 1 to 3 were injection molded into standard nylon material specimens. The tensile modulus of the nylon material specimens was tested according to ISO 527-1 / -2; the yield stress of the nylon material specimens was tested according to ISO 527-1 / -2; the Charpy notched impact strength of the nylon material specimens was tested according to ISO 179 / 1eA; and the water absorption and moisture absorption of the nylon material specimens were tested according to ISO 62.

[0149] The hydrophobic high-strength transparent nylon prepared in Examples 1 to 8 and the nylon prepared in Comparative Examples 1 to 2 were respectively made into film strips, and the transmittance of the strips was tested using an ultraviolet-visible spectrophotometer according to GB / T 2410-2008.

[0150] The test results are shown in Table 1.

[0151] Table 1

[0152]

[0153] The data in Table 1 show that the hydrophobic, high-strength, transparent nylon prepared in Examples 1-8 exhibits improved tensile modulus, yield stress, notched Charpy impact strength, and light transmittance compared to the nylon prepared in Comparative Examples 1-3. The water absorption and moisture absorption rates of Examples 1-8 are both reduced, with significant improvements in notched Charpy impact strength and light transmittance. As shown in Table 1, the hydrophobic, high-strength, transparent nylon prepared in accordance with the present invention exhibits excellent mechanical properties, hydrophobicity, and light transmittance.

[0154] Example 1 differs from Comparative Example 1 in the polymerization reaction conditions (temperature, pressure, time, etc.). Compared to the nylon prepared in Comparative Example 1, the nylon prepared in Example 1 exhibits improved tensile modulus, yield stress, notched impact strength, and light transmittance, while significantly reducing water and moisture absorption. Specifically, the tensile modulus increased by 0.48%, the yield stress increased by 14.08%, the notched impact strength increased by 2.94%, the light transmittance increased by 6.02%, the water absorption decreased by 16.67%, and the moisture absorption decreased by 20.00%. This demonstrates that the present invention improves the mechanical and optical properties of nylon by regulating the polymerization reaction process.

[0155] The difference between Example 1 and Comparative Example 2 lies in the different monomer ratios. Compared to the nylon prepared in Comparative Example 2, the nylon prepared in Example 1 exhibits significantly improved tensile modulus, yield stress, notched impact strength, and light transmittance, while significantly reducing water and hygroscopicity. Specifically, the tensile modulus increased by 3.76%, the yield stress increased by 20.90%, the notched impact strength increased by 20.69%, and the light transmittance increased by 12.82%, while the water absorption decreased by 36.36% and the hygroscopicity decreased by 15.79%. This demonstrates that the present invention improves the mechanical, optical, and hydrophobic properties of nylon by adjusting the ratio of the reactive units.

[0156] The difference between Example 1 and Comparative Example 3 lies in the different types of monomers used. Example 1 adds MACM, while Comparative Example 3 does not. The structure of the nylon in Example 1 is different from that of the nylon in Comparative Example 3. Compared with the nylon in Comparative Example 3, the tensile modulus, yield stress, notched impact strength, and light transmittance of the nylon prepared in Example 1 are greatly improved, while the water absorption and moisture absorption are greatly reduced; among them, the tensile modulus is increased by 4.71%, the yield stress is increased by 35.00%, the notched impact strength is increased by 42.86%, the light transmittance is increased by 25.71%, the water absorption is reduced by 58.33%, and the moisture absorption is reduced by 42.86%. This shows that the present invention changes the specific structure of nylon by adding MACM, thereby improving the mechanical properties, optical properties, and hydrophobic properties of nylon.

[0157] In summary, the hydrophobic transparent nylon provided by the present invention improves hydrophobicity on the basis of better balancing mechanical properties and optical properties, and reduces the water absorption and hygroscopicity of the material. The structural unit composed of MACM, benzene ring and fatty chain has both rigidity and ductility. The methyl groups of MACM and benzene ring destroy the lattice structure of the molecule, improve the transmittance, and synergistically reduce the density of amide bonds in the molecule with the fatty chain, thereby improving hydrophobicity. The antioxidants, light stabilizers and hydrophobic agents added to the raw monomers can further improve the weather resistance, water absorption and hygroscopicity of the material in application and delay the yellowing process. Therefore, the hydrophobic transparent nylon provided by the present invention has great application prospects and value.

Claims

1. A hydrophobic transparent nylon comprising a polymer as shown in Formula I; In formula I, m and n are independently any integer between 500 and 5000, p is any integer between 1 and 12, and the NH group on the benzene ring is located at the 3rd or 4th position of the benzene ring.

2. The hydrophobic transparent nylon according to claim 1, characterized in that Formula I is selected from One of them.

3. The hydrophobic transparent nylon according to claim 1, wherein The invention is prepared from raw materials including 3,3'-dimethyl-4,4-diaminodicyclohexylmethane, aromatic diamine, fatty diacid and hydrophobic agent.

4. A method for preparing the hydrophobic transparent nylon according to any one of claims 1 to 3, comprising: (1) mixing 3,3'-dimethyl-4,4-diaminodicyclohexylmethane, aromatic diamine, fatty diacid, catalyst, antioxidant, light stabilizer, hydrophobic agent and deionized water to obtain a mixed material; (2) Under an inert atmosphere, the mixed material is subjected to a condensation reaction.

5. The preparation method according to claim 4, wherein The aromatic diamine is selected from methyl-substituted phenylenediamine, preferably at least one selected from 2-methyl-1,4-phenylenediamine and 2-methyl-1,3-phenylenediamine; or / and, The fatty diacid is selected from C3-C14 straight-chain fatty diacids, preferably at least one selected from malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, 1,10-decanedioic acid, 1,11-undecanoic acid, 1,12-dodecanoic acid, 1,13-tridecanoic acid and 1,14-tetradecanoic acid; or / and, The catalyst is selected from at least one of N,N-dimethylcyclohexylamine, bis(2-dimethylaminoethyl) ether, N,N,N',N'-tetramethylalkylenediamine, triethylamine, N,N-dimethylbenzylamine, solid amine, N-ethylmorpholine, N-methylmorpholine, N,N-diethylpiperazine, potassium phosphate, sodium phosphate, potassium hypophosphite, sodium hypophosphite, potassium phosphite, sodium phosphite, potassium hypophosphite, sodium hypophosphite, n-butyl titanate, propyl titanate and isopropyl titanate; or / and, The antioxidant is at least one selected from pentaerythritol tetrakis (3,5-di-tert-butyl-4-hydroxyhydrocinnamate), β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyl) hexanediamine, tris (2,4-di-tert-butyl) phenyl phosphite, potassium iodide, copper salt; or / and, The light stabilizer is selected from at least one of UV-3346, UV-123, UV-292, UV-622, UV-770DF, UV-944, UV-2020, and UV-660; or / and, The hydrophobic agent is selected from at least one of glass fiber, carbon fiber, talc, mica, silicon dioxide, polyolefin, polyphenylene ether, polyphenylene sulfide, and polytetrafluoroethylene.

6. The preparation method according to claim 4, wherein The molar ratio of the fatty diacid to the aromatic diamine is 2:(0.6-1.4), preferably 2:(0.8-1.2); or / and, The molar ratio of the aromatic diamine to 3,3'-dimethyl-4,4-diaminodicyclohexylmethane is 1:(0.6-1.4), preferably 1:(0.8-1.2); or / and, The amount of the catalyst added is 0.05% to 0.30% of the total mass of the fatty diacid, aromatic diamine and 3,3'-dimethyl-4,4-diaminodicyclohexylmethane, preferably 0.10% to 0.25%; or / and, The added amount of the antioxidant is 0.1% to 1.0% of the total mass of the fatty diacid, aromatic diamine and 3,3'-dimethyl-4,4-diaminodicyclohexylmethane, preferably 0.10% to 0.8%; or / and, The amount of the light stabilizer added is 0.08% to 0.20% of the total mass of the fatty diacid, aromatic diamine and 3,3'-dimethyl-4,4-diaminodicyclohexylmethane, preferably 0.11% to 0.15%; or / and, The amount of the hydrophobic agent added is 0.5% to 5.0% of the total mass of the fatty diacid, aromatic diamine and 3,3'-dimethyl-4,4-diaminodicyclohexylmethane, preferably 0.80% to 4.5%; or / and, The added amount of the deionized water is 35% to 65% of the total mass of the fatty diacid, phenylenediamine and 3,3'-dimethyl-4,4-diaminodicyclohexylmethane, preferably 40% to 60%.

7. The preparation method according to claim 4, wherein The condensation reaction includes a first stage reaction, a second stage reaction and a third stage reaction which are carried out in sequence: The first stage reaction conditions are: 255-300°C, 2.5-3 MPa, reaction time 3.0-3.5 hours; The reaction conditions for the second stage are: 310-320°C, 0.3-0.4 MPa, reaction time 2.2-2.5 hours; The reaction conditions for the third stage are: room temperature and normal pressure for 1 to 1.5 hours.

8. The preparation method according to claim 4, wherein: The first stage reaction conditions are: 260-290℃, 2.6-3MPa, reaction time 3-3.2h, The reaction conditions for the second stage are: 310-315°C, 0.3-0.35 MPa, reaction time 2.2-2.4 hours, The reaction conditions for the third stage are: room temperature and normal pressure for 1 to 1.3 hours.

9. The preparation method according to claim 4, wherein: The condensation reaction is carried out under stirring conditions with a stirring speed of 300 to 500 r / min; or / and, The inert atmosphere is a nitrogen atmosphere.

10. Use of the hydrophobic transparent nylon according to any one of claims 1 to 3 or the hydrophobic transparent nylon prepared by the preparation method according to any one of claims 4 to 9 in the fields of food and beverage packaging, medical devices, precision instruments, optical instruments, electronic appliances, automobile manufacturing, machinery, aviation, and sporting goods.

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