Paint-free memory NANO nylon resin and preparation method therefor

Abstract

The present invention relates to the technical field of polymer compositions, and specifically discloses a paintless memory nylon nanostructure and a preparation method thereof.SOLUTION: The nylon resin includes the following raw materials in parts by weight: 40-70 parts of modified nylon, 10-20 parts of styrene-butadiene-acrylonitrile copolymer, 5-10 parts of compatibilizer, 0. 5-5 parts of antioxidant, 2-10 parts of lubricant, and 1-5 parts of pigment. The present invention also provides a method for producing the same. Compared with the prior art, the nylon resin of the present invention has excellent toughness and elasticity, can be bent and twisted to restore the original shape, has a smooth surface, and does not need to be painted after molding.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to the technical field of polymer compound compositions, and in particular to a paint-free memory nano nylon resin and a method for producing the same. [Background technology]

[0002] Materials that can restore their original shape in response to external factors such as temperature, magnetic fields, and light are called shape memory materials. Shape memory polymers, in particular, are popular due to their ease of fabrication, low production cost, excellent shape memory function, and high customizability, and are therefore used in many fields, including medicine, self-healing materials, aerospace, and heat-shrinkable materials. The main matrices for these polymers include polyester, polyurethane, polyethylene, and the like. Currently, shape memory polymers face several challenges in practical applications, primarily due to limitations in the substrate itself, such as insufficient mechanical strength and poor chemical stability. These issues limit the further application and development of shape memory materials.

[0003] CN202011163136.6 discloses a nylon 6 composition with excellent shape memory performance, prepared in parts by weight from 100 parts by weight of caprolactam, 5-10 parts by weight of caprolactone, 1-2 parts by weight of a catalyst, 0.5-1 part by weight of an activator, 3-5 parts by weight of acicular nanohydroxyapatite, and 1-2 parts by weight of an antioxidant. The invention also discloses a method for producing the nylon 6 composition. The invention significantly improves the shape memory performance of the composition by adding caprolactone and acicular nanohydroxyapatite to caprolactone in a reasonable ratio. Neither excess caprolactone, excess acicular nanohydroxyapatite, nor large-particle or spherical hydroxyapatite can improve the shape memory performance of the composition.

[0004] CN201410247150.2 discloses a memory-enhancing nylon rubber plastic material containing modified nylon, maleic anhydride graft copolymer, and auxiliary agents in the following weight percentages: 35-42% caprolactam, 5-25% vinyl-terminated phenylsilicone oil, 0.1-0.5% initiator, 1-10% aromatic diacid, 15-40% polyether, 0.1-1.1% catalyst, 1-10% chain extender, and 0.5-1.5% antioxidant. The invention also discloses a method for producing the memory-enhancing nylon rubber plastic material. This invention uses vinyl-terminated phenylsilicone oil to modify the polyamide hard segment of nylon, thereby enhancing the nylon's overall performance, including low-temperature toughness, oxidation resistance, weather resistance, heat resistance, and flame retardancy. The modified nylon is then toughened with a maleic anhydride graft copolymer, resulting in a nylon rubber-plastic material with the properties of both plastic and rubber, improving its shape recovery memory effect and overall mechanical properties. This overcomes the problems of poor elasticity and shape recovery in ordinary nylon or plastic materials, and improves the memory properties of products such as earphone cables.

[0005] Nylon, a high-performance engineering plastic, contains a large number of polar amide bonds in its molecular structure. These bonds form strong hydrogen bonds between molecular chains, strengthening the material's cohesion. At the same time, nylon's molecular chains exhibit high order and crystallinity. Furthermore, the methylene groups in nylon's molecular chains provide excellent flexibility. In addition to its excellent mechanical properties, nylon also exhibits excellent low-temperature performance, electrical insulation, and chemical stability. Therefore, developing new shape-memory materials based on nylon is expected to enhance these materials' performance and open up broader market prospects. However, there is currently little research on shape-memory materials with a nylon matrix, and deficiencies, such as poor mechanical properties, are urgently needed. Summary of the Invention

[0006] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a paint-free memory nano nylon resin and a method for producing the same.

[0007] Nylon materials have limited application in the field of shape memory materials due to their poor dimensional stability and low-temperature toughness, as well as insufficient heat resistance and toughness. In contrast, in this invention, amino-terminated nylon is first prepared as a matrix, and then used as a hard segment with an appropriate molecular weight to anchor the material. However, its excessive molecular weight imparts high strength and modulus to the material, preventing shape memory behavior. Furthermore, the soft segment is obtained by blending (dibenzyl-4,4'-diyl)diisocyanate, polytetrahydrofurazan, and trimethylolpropane, thereby serving as a deformable material. Modified nylon is obtained by polymerizing the hard and soft segments, and the soft and hard segments form a microphase-separated structure in the system. The formation of this microphase-separated structure plays a crucial role in shape memory. The modified nylon thus produced has strong rigidity, good flexibility, and excellent resilience, allowing it to quickly recover to its original shape after deformation. Furthermore, since the styrene-butadiene-acrylonitrile copolymer can impart good gloss to the material, the resulting resin has good gloss, does not require painting, and makes the application process easier.

[0008] To achieve the above object, the present invention provides an unpainted memory nano nylon resin containing, as raw materials, 40 to 70 parts by weight of modified nylon, 10 to 20 parts by weight of styrene-butadiene-acrylonitrile copolymer, 5 to 10 parts by weight of compatibilizer, 0.5 to 5 parts by weight of antioxidant, 2 to 10 parts by weight of lubricant, and 1 to 5 parts by weight of pigment.

[0009] Furthermore, the compatibilizer is a copolymer of maleic anhydride grafted ethylene and octene.

[0010] Furthermore, the antioxidant is one of n-octadecyl-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, tetrakis[β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]tetraxtetrol, and N,N'-bis-(3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyl)hexanediamine.

[0011] Furthermore, the lubricant is one of calcium stearate, polyethylene wax, or magnesium carbonate.

[0012] Furthermore, the pigment is carbon black.

[0013] The method for producing the modified nylon includes the steps of: X1: Methylene succinic acid is added to absolute ethanol to obtain solution A, tetramethylene diamine is added to absolute ethanol to obtain solution B, solution B is added to solution A, heated to 60-80°C, stirred for 1-2 hours, cooled to room temperature, filtered, the residue is dried, heated to 140-150°C in an inert atmosphere to melt, then heated to 150-160°C, maintained for 2-3 hours, vacuumed, melt polycondensed for 4-6 hours, and then tetramethylene diamine is added to stop the reaction, thereby obtaining amino-terminated nylon; X2: (Dibenzyl-4,4'-diyl) diisocyanate and polytetrahydrofuran are mixed in an inert atmosphere, heated to 70 to 80°C, and prepolymerized for 1 to 2 hours, and then trimethylolpropane is added and polymerization is continued for 1 to 2 hours. After the reaction is completed, the resulting mixture is used in the next step as is; X3: The amino-terminated nylon and the product of the previous step are uniformly mixed in a molar ratio of 1:1, and then the mixture is heated to 180-200°C and stirred for 1-2 hours to polymerize the mixture to obtain a modified nylon.

[0014] Furthermore, the heating temperature in step X2 is 70 to 80°C.

[0015] Furthermore, the heating temperature in step X3 is 180 to 200°C.

[0016] Preferably, the method for producing the modified nylon comprises: X1: 10 to 15 parts by weight of methylene succinic acid is added to 50 to 100 parts by weight of absolute ethanol to obtain solution A, 5 to 15 parts by weight of tetramethylenediamine is added to 30 to 50 parts by weight of absolute ethanol to obtain solution B, solution B is added to solution A, heated to 60 to 80°C, stirred for 1 to 2 hours, cooled to room temperature, filtered, the residue is dried, heated to 140 to 150°C in an inert atmosphere to melt, then heated to 150 to 160°C, maintained for 2 to 3 hours, vacuumed, melt polycondensed for 4 to 6 hours, and then 2% by weight of tetramethylenediamine of the residue is added to terminate the reaction, thereby obtaining amino-terminated nylon; X2: 30 to 60 parts by weight of (dibenzyl-4,4'-diyl)diisocyanate and 100 to 250 parts by weight of polytetrahydrofuran are mixed in an inert atmosphere, heated to 70 to 80°C and prepolymerized for 1 to 2 hours, and then 20 to 40 parts by weight of trimethylolpropane is added and polymerization is continued for 1 to 2 hours. After the reaction is completed, the mixture is used as it is in the next step. X3: The amino-terminated nylon and the product of the previous step are uniformly mixed in a molar ratio of 1:1, and then the mixture is heated to 180-200°C and stirred for 1-2 hours to polymerize the mixture to obtain a modified nylon.

[0017] A method for producing unpainted memory nano nylon resin, S1: After mixing the raw materials in the appropriate ratio, the mixture is stirred and mixed at a constant rotation speed at 80-100°C, and then kneaded and extruded. S2: The extrudate is water-cooled and pelletized to obtain the product.

[0018] Furthermore, the rotation speed is 1000 to 1500 rpm.

[0019] Furthermore, the kneading temperature is 150 to 200°C. [Effects of the Invention]

[0020] The beneficial effects of the present invention are as follows: 1. Compared with the prior art, in this invention, amino-terminated nylon is used as a hard segment to impart rigidity to the internal structure, and soft segments are obtained after polymerizing polytetrahydrofuran. Modified nylon is obtained after polymerizing the hard and soft segments, and the soft and hard segments form a microphase-separated structure in the system. The construction of this microphase-separated structure plays a crucial role in shape memory, so the modified nylon prepared has strong rigidity and good flexibility. 2. The nylon resin prepared by the present invention has excellent toughness and resilience, and can return to its original shape even after being bent and twisted. Its surface is smooth and does not require painting after molding. DETAILED DESCRIPTION OF THE INVENTION

[0021] (Bibenzyl-4,4'-diyl)diisocyanate, CAS number: 1034-24-8.

[0022] Polytetrahydrofuran, Mw=2000, Model No.: DYT-005, Daytai.

[0023] Styrene-butadiene-acrylonitrile copolymer, grade: TR-530F, Shanghai Yi Plastics new material.

[0024] Maleic anhydride grafted ethylene and octene copolymer, model number: Tao 8137, Dongguan Yingxiang Plastic Raw Materials.

[0025] Comparative Example 1 A method for producing unpainted memory nano nylon resin, S1: 500g of modified nylon, 150g of styrene-butadiene-acrylonitrile copolymer, 80g of a copolymer of maleic anhydride grafted ethylene and octadiene, 5g of n-octadecyl-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 50g of calcium stearate, and 20g of carbon black are mixed, stirred and mixed at 80℃ and 1200 rpm, injected, and then kneaded and extruded at 160℃; S2: The extrudate is water-cooled and pelletized to obtain the product.

[0026] The method for producing the modified nylon includes the steps of: X1: 130 g of methylene succinic acid is added to 650 mL of absolute ethanol to obtain solution A, 90 g of tetramethylene diamine is added to 400 mL of absolute ethanol to obtain solution B, solution B is added to solution A, heated to 70°C, stirred for 1 hour, cooled to room temperature, filtered, the residue is dried, heated to 150°C in an inert atmosphere to melt, then heated to 160°C, maintained for 3 hours, vacuumed, melt polycondensed for 6 hours, and then 2 wt% of the residue is added to tetramethylene diamine to stop the reaction, thereby obtaining amino-terminated nylon; X2: 500 g of (dibenzyl-4,4'-diyl) diisocyanate and 1900 g of polytetrahydrofuran were mixed under an inert atmosphere, heated to 75°C and polymerized for 2 hours, and after the reaction was completed, the mixture was used in the next step as is; X3: The amino-terminated nylon and the product of the previous step are mixed uniformly in a molar ratio of 1:1, and then heated to 190°C and stirred for 2 hours to polymerize the mixture to obtain modified nylon.

[0027] Comparative Example 2 A method for producing unpainted memory nano nylon resin, S1: 500g of modified nylon, 150g of styrene-butadiene-acrylonitrile copolymer, 80g of a copolymer of maleic anhydride grafted ethylene and octadiene, 5g of n-octadecyl-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 50g of calcium stearate, and 20g of carbon black are mixed, stirred and mixed at 80℃ and 1200 rpm, injected, and then kneaded and extruded at 160℃; S2: The extrudate is water-cooled and pelletized to obtain the product.

[0028] The method for producing the modified nylon includes the steps of: This product includes a mixture of 1,000 g of caprolactam, 80 g of caprolactone, and 20 g of sodium hydroxide, which is then heated to 120°C, subjected to negative pressure for 20 minutes to remove water, stirred for 1 hour, and then 15 g of (dibenzyl-4,4'-diyl)diisocyanate is added and polymerized at 180°C for 1 hour.

[0029] Example 1 A method for producing unpainted memory nano nylon resin, S1: 500g of modified nylon, 150g of styrene-butadiene-acrylonitrile copolymer, 80g of a copolymer of maleic anhydride grafted ethylene and octadiene, 5g of n-octadecyl-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 50g of calcium stearate, and 20g of carbon black are mixed, stirred and mixed at 80℃ and 1200 rpm, injected, and then kneaded and extruded at 160℃; S2: The extrudate is water-cooled and pelletized to obtain the product.

[0030] The method for producing the modified nylon includes the steps of: X1: 130 g of methylene succinic acid is added to 650 mL of absolute ethanol to obtain solution A, 90 g of tetramethylene diamine is added to 400 mL of absolute ethanol to obtain solution B, solution B is added to solution A, heated to 70°C, stirred for 1 hour, cooled to room temperature, filtered, the residue is dried, heated to 150°C in an inert atmosphere to melt, then heated to 160°C, maintained for 3 hours, vacuumed, melt polycondensed for 6 hours, and then 2 wt% of the residue is added to tetramethylene diamine to stop the reaction, thereby obtaining amino-terminated nylon; X2: 500 g of (dibenzyl-4,4'-diyl) diisocyanate and 1900 g of polytetrahydrofuran were mixed under an inert atmosphere, heated to 75°C and prepolymerized for 2 hours, and then 30 g of trimethylolpropane was added and polymerization was continued for 2 hours. After the reaction was completed, the resulting mixture was used in the next step as it was. X3: The amino-terminated nylon and the product of the previous step are mixed uniformly in a molar ratio of 1:1, and then heated to 190°C and stirred for 2 hours to polymerize the mixture to obtain modified nylon.

[0031] Example 2 Compared with Example 1, the only difference is that the amount of styrene-butadiene-acrylonitrile copolymer is 120 g.

[0032] Example 3 Compared with Example 1, the only difference is that the amount of styrene-butadiene-acrylonitrile copolymer is 170 g.

[0033] Example 4 Compared to Example 1, the only difference is that the amount of carbon black is 10 g.

[0034] Example 5 Compared to Example 1, the only difference is that the amount of carbon black is 30 g.

[0035] Test Example 1 The nylon resins in the comparative examples and examples were tested for mechanical properties, including tensile strength and elongation at break, in accordance with GB / T 1043.3-2006 "Methods for Determining Tensile Properties of Plastics, Part 3: Test Conditions for Films and Sheets," at a tensile speed of 50 mm / min. The gloss of the nylon resin materials was measured in accordance with ISO 2813-2014 "Method for Determining Gloss of Paints and Varnishes at -20°, 60°, and 85° Angle."

[0036] Table 1: Mechanical properties and gloss test of nylon resin [Table 1]

[0037] As can be seen from Table 1, the nylon resin produced in the embodiment has significantly better tensile strength and resilience than the conventional shape memory nylon material in Comparative Example 2. This is because, in the embodiment, the amino-terminated nylon acts as a hard segment to impart rigidity to the structure, the soft segment is obtained after polymerization of polytetrahydrofuran, and the modified nylon is obtained after polymerization of the hard and soft segments. The soft and hard segments form a microphase-separated structure within the system, and this microphase-separated structure plays a crucial role in shape memory, resulting in the modified nylon having strong rigidity and excellent flexibility. On the other hand, in Comparative Example 1, when the soft segment was obtained using polytetrahydrofuran as a matrix, the addition of trimethylolpropane resulted in a smaller soft segment structure and fewer crosslinking points, resulting in a lower degree of crosslinking in the modified nylon and affecting the mechanical properties of the material. In Example 1, the soft and hard segments have multiple crosslinking sites during polymerization, allowing for the formation of a denser structure. Compared to Example 1, Examples 2 and 3 have different amounts of styrene-butadiene-acrylonitrile copolymer, which results in different gloss levels for the materials, but there is little difference between Example 3 and Example 2. Compared to Example 1, Examples 4 and 5 have different amounts of carbon black, which results in different black brightness for the materials, which affects gloss levels. However, the dispersibility of carbon black is poor, and if the amount is too high, it adversely affects the mechanical properties of the material, so the material performance in Example 1 is relatively optimal.

[0038] Test Example 2 A shape memory test was conducted on the nylon resins produced in the comparative examples and examples. The test method was as follows: A sample with a length of L0 was held at 80°C for 10 minutes, then stretched to 200% at a tensile rate of 10 mm / min. After 10 minutes, the temperature was lowered to 30°C and the sample was allowed to crystallize for 10 minutes. The length of the sample at this time was recorded as L1. The stress was then removed, and the sample's length L2 was measured after 10 minutes. The sample was then heated again to 230°C and held for 10 minutes. After cooling to 30°C and holding for 30 minutes, the sample's length L3 was recorded. Shape fixation rate: Rf = (L2 - L0) / (L1 - L0) x 100%, and shape recovery rate: Rr = (L2 - L3) / (L2 - L0) x 100%.

[0039] Table 2: Shape memory test for nylon resin [Table 2]

[0040] The nylon resin of the present invention is composed of hard and soft segments interdigitated with each other, resulting in a two-phase aggregate structure within the system. While the soft segments have a low melting point or glass transition temperature, the hard segments generally have a high melting point or glass transition temperature, resulting in shape memory properties. When an amino-terminated nylon is used as the stationary phase in the main chain and a polymer derived from polytetrahydrofuran is used as the reversible phase, the material is endowed with shape memory properties through processing deformation, and can undergo material changes upon exposure to stimuli such as deformation or temperature changes. However, due to the material's good resilience, it can quickly return to its original shape. As can be seen from the shape memory tests, all of the nylon resins produced in the examples exhibited good resilience, resulting in significant differences in the shape test data between Examples 1 to 5. This is because the relationship between shape memory properties and modified nylon is greatest. Although the amount of modified nylon used in each example is the same, the tensile properties affect the shape after deformation to some extent, resulting in inconsistent shape memory performance between examples. Compared to Comparative Example 1, in Example 1, trimethylolpropane was not added when obtaining the soft segments using polytetrahydrofuran as a matrix, resulting in a smaller soft segment structure and fewer crosslinking points, resulting in a lower degree of crosslinking of the modified nylon. However, the orientation of the soft segments obtained in Example 1 was greater, resulting in better resilience. Compared to Comparative Example 2, in Example 1, the amino-terminated nylon acts as a hard segment to impart rigidity to the structure, the soft segments are obtained after polymerization of polytetrahydrofuran, and the modified nylon is obtained after polymerization of the hard segments and soft segments. The soft segments and hard segments form a microphase-separated structure within the system, and the construction of the microphase-separated structure plays a crucial role in shape memory, resulting in the modified nylon having better flexibility.

[0041] The above is a detailed description of the preferred specific embodiments of the present invention. It should be understood that those skilled in the art can make many modifications and changes based on the concept of the present invention without any creative effort. Therefore, any technical solution that those skilled in the art can obtain based on the concept of the present invention through logical analysis, reasoning, or limited experiments based on the prior art should be included within the scope of protection defined by the claims.

Claims

1. Unpainted memory nano nylon resin, The raw materials are 40 to 70 parts by weight of modified nylon, 10 to 20 parts by weight of styrene-butadiene-acrylonitrile copolymer, 5 to 10 parts by weight of compatibilizer, 0.5 to 5 parts by weight of antioxidant, 2 to 10 parts by weight of lubricant, and 1 to 5 parts by weight of pigment, The method for producing the modified nylon includes the steps of: X1: 10 to 15 parts by weight of methylene succinic acid is added to 50 to 100 parts by weight of absolute ethanol to obtain solution A, 5 to 15 parts by weight of tetramethylene diamine is added to 30 to 50 parts by weight of absolute ethanol to obtain solution B, solution B is added to solution A, heated to 60 to 80°C, stirred for 1 to 2 hours, cooled to room temperature, filtered, the residue is dried, heated to 140 to 150°C in an inert atmosphere to melt, then heated to 150 to 160°C, maintained for 2 to 3 hours, vacuumed, melt polycondensed for 4 to 6 hours, and then 2% by weight of tetramethylene diamine is added to the residue to terminate the reaction, thereby obtaining amino-terminated nylon; X2: 30 to 60 parts by weight of (dibenzyl-4,4'-diyl) diisocyanate and 100 to 250 parts by weight of polytetrahydrofuran are mixed in an inert atmosphere, heated to 70 to 80°C and prepolymerized for 1 to 2 hours, and then 20 to 40 parts by weight of trimethylolpropane is added and polymerization is continued for 1 to 2 hours. After the reaction is completed, the mixture is used in the next step as is; X3: The amino-terminated nylon and the product of the previous step are uniformly mixed in a molar ratio of 1:1, and then heated to 180-200°C and stirred for 1-2 hours to polymerize the mixture to obtain a modified nylon. Unpainted memory nano nylon resin.

2. The compatibilizer is a copolymer of maleic anhydride grafted ethylene and octene. The unpainted memory nano nylon resin according to claim 1.

3. The antioxidant is one of n-octadecyl-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, tetrakis[β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]tetraxtetrol, and N,N'-bis-(3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyl)hexanediamine; The unpainted memory nano nylon resin according to claim 1.

4. The lubricant is one of calcium stearate, polyethylene wax, or magnesium carbonate. The unpainted memory nano nylon resin according to claim 1.

5. The pigment is carbon black. The unpainted memory nano nylon resin according to claim 1.

6. A method for producing the unpainted memory nano nylon resin according to any one of claims 1 to 5, S1: After mixing the raw materials in the appropriate ratio, the mixture is stirred and mixed at a constant rotation speed at 80 to 100°C, and then the mixture is kneaded and extruded. S2: The extrudate is water-cooled and pelletized to obtain a product; A method for producing unpainted memory nano nylon resin.

7. The rotation speed is 1000 to 1500 rpm, and the kneading temperature is 150 to 200°C. The method for producing the unpainted memory nano nylon resin according to claim 6.

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