Nylon sheath material for wire and cable and preparation method thereof

Abstract

The present application relates to the field of cable materials, in particular to a nylon sheath material for wires and cables, comprising nylon 6, nylon 12, a block copolymer compatibilizer, an antioxidant, and a lubricant; the preparation method of the block copolymer compatibilizer is as follows: 1) polylaurolactam and N-benzoyl-laurolactam are reacted at 100-120°C for 2-3 hours under a protective gas atmosphere, and then dried to remove unreacted monomers after cooling to obtain an activator; 2) nylon 6 prepolymer and nylon 12 prepolymer are uniformly mixed, an activator is added to obtain a mixture; the mixture is melt copolymerized at 240-260°C for 30-60 minutes to obtain a nylon 6-nylon 12 alternating block structure; 3) the nylon 6-nylon 12 alternating block structure obtained in 2) is extruded and granulated, water-cooled, and then dried to remove unreacted homopolymer to obtain a block copolymer compatibilizer. The obtained material has excellent comprehensive properties of elongation at break, impact strength, and flexural strength.

Description

Technical Field

[0001] The present application relates to the field of cable materials, and in particular to a nylon sheath material for wires and cables and a preparation method thereof. Background Art

[0002] Wires and cables are carriers for transmitting signals and are a collection of the following parts: one or more insulated cores, and their respective coatings, total protective layers and outer sheaths.

[0003] Commonly used sheath materials include polyurethane acrylate, PVC, nylon, etc. Among them, nylon is favored because of its good comprehensive properties, including mechanical properties, heat resistance, wear resistance, chemical resistance and self-lubrication.

[0004] There are various types of wires and cables. Some wires and cables need to be wound or coiled during use, which requires the nylon sheath material to have excellent elongation at break and good unnotched or notched impact strength. Nylon has poor dimensional stability and low unnotched or notched impact strength in dry state and low temperature environment. To this end, the method adopted by researchers is usually to add a toughening agent. For example, Chinese patent application number 201010617355.7 discloses a toughened nylon blend and its preparation method. The toughening agent is prepared by grafting and modifying a blend of three materials: ethylene-1-octene copolymer (POE), polypropylene (PP), and ethylene acrylic acid copolymer (EAA) with a polar monomer. The toughened nylon blend obtained by blending the toughening agent with nylon not only has good toughness, but also better maintains the strength of the nylon itself, greatly expanding the application range of nylon.

[0005] Regarding the above-mentioned related technologies, the applicant found that the elongation at break thereof could not meet the requirements under some winding conditions and needed to be further improved. Summary of the Invention

[0006] In order to improve the elongation at break of nylon sheathing materials for wires and cables, the present application provides a nylon sheathing material for wires and cables and a preparation method thereof.

[0007] In a first aspect, the present application provides a nylon sheath material for wires and cables, which adopts the following technical solution.

[0008] A nylon sheath material for wires and cables, comprising the following raw materials: nylon 6, nylon 12, a block copolymer compatibilizer, an antioxidant, and a lubricant;

[0009] The preparation method of the block copolymer compatibilizer is:

[0010] 1) Preparation of activator

[0011] Polylaurolactam and N-benzoyl-laurolactam are reacted at 100-120° C. for 2-3 hours under a protective gas atmosphere, and then dried to remove unreacted monomers to obtain an activator;

[0012] 2) Block copolymer synthesis

[0013] The nylon 6 prepolymer and the nylon 12 prepolymer are uniformly mixed, and then an activator is added to obtain a mixture; the mixture is melt copolymerized at 240-260° C. for 30-60 minutes to obtain a nylon 6-nylon 12 alternating block structure;

[0014] 3) Post-processing and purification

[0015] The nylon 6-nylon 12 alternating block structure obtained in 2) is extruded into granules, water-cooled and then dried to remove unreacted homopolymer to obtain a block copolymer compatibilizer.

[0016] By adopting the above technical solution, nylon 6 and nylon 12 are compounded as the base material. The molecular chain of nylon 6 contains more polar amide groups (NHCO), which gives it high rigidity and heat resistance. The molecular chain of nylon 12 has a high proportion of long carbon chain methylene (-CH2-), which provides flexibility. After compounding, the molecular chains of the two are combined through hydrogen bonds and van der Waals forces to form a rigid and flexible blend system. Nylon 6 is a semi-crystalline material with high crystallinity, while nylon 12 has a lower degree of crystallinity. When the two are compounded, the crystalline region of nylon 6 can serve as a physical crosslinking point to enhance the rigidity of the material, while the amorphous region of nylon 12 provides elasticity, forming a microscopic phase separation structure and improving impact resistance.

[0017] However, nylon 6 and nylon 12 are incompatible at the molecular level, which results in poor mechanical properties of the resulting composite material. This application uses an activator to trigger block copolymerization, combined with an acidolysis reaction to optimize the molecular structure, to efficiently prepare PA6-PA12 block copolymers. The molecular chains contain structural units of both PA6 and PA12. Physical entanglement and chemical bonding between the molecular chains reduce the interfacial tension between the two phases, reducing the phase separation size of the PA6 / PA12 blend from the micron level to the submicron level, significantly improving the molecular compatibility of the two phases. This improves the material's elongation at break, impact strength, and flexural strength.

[0018] Furthermore, the weight ratio of the nylon 6 prepolymer to the nylon 12 prepolymer is 1:(1-1.2).

[0019] Furthermore, the weight ratio of the polylauryl lactam to N-benzoyl-lauryl lactam is 1:(1.1-1.4).

[0020] Furthermore, the weight ratio of the nylon 6 prepolymer to the nylon 7 prepolymer and the activator is 100:(0.5-1.5).

[0021] Furthermore, the weight ratio of nylon 6 to nylon 12 is 1:(1.5-3).

[0022] Furthermore, the weight ratio of the nylon to nylon 7 and the block copolymer compatibilizer is 100:(3-7).

[0023] Furthermore, the nylon 6 includes nylon 6 with a Shore hardness of 65D and nylon 6 with a Shore hardness of 70D, and the weight ratio of nylon 6 with a Shore hardness of 65D to nylon 6 with a Shore hardness of 70D is (2-4):1.

[0024] Furthermore, the molecular weight of the polylaurolactam is 4000-6000 g / mol.

[0025] Furthermore, the nylon 6 prepolymer is an amino-terminated type with a molecular weight of 3000-5000 g / mol; the nylon 12 prepolymer is a carboxyl-terminated type with a molecular weight of 4000-6000 g / mol.

[0026] In a second aspect, the present application provides a method for preparing nylon sheath material for wires and cables, adopting the following technical solution.

[0027] Nylon 6 and nylon 12 are dried, mixed with the remaining other raw materials, melted, extruded and granulated at a temperature of 220-230°C, and dried after extrusion and granulation to obtain nylon sheath material for wires and cables.

[0028] In summary, this application has the following beneficial effects:

[0029] This application uses a compound of nylon 6 and nylon 12 as the base material, and a PA6-PA12 block copolymer as a compatibilizer. Its molecular chain contains structural units of both PA6 and PA12. The physical entanglement and chemical bonding between the molecular chains reduce the interfacial tension between the two phases, reducing the phase separation size of the PA6 / PA12 blend from the micron level to the submicron level, significantly improving the molecular compatibility of nylon 6 and nylon 12. After compounding, the molecular chains of nylon 6 and nylon 12 are combined through hydrogen bonds and van der Waals forces to form a rigid and flexible blend system. Nylon 6 is a semi-crystalline material with high crystallinity, while nylon 12 has a lower degree of crystallinity. When the two are compounded, the crystalline region of nylon 6 can serve as a physical cross-linking point to enhance the rigidity of the material, while the amorphous region of nylon 12 provides elasticity, forming a microscopic phase separation structure and improving impact resistance. The resulting material can achieve an elongation at break of 375% and an impact strength of 92 kJ·m 2 , the bending strength can reach 38MPa. DETAILED DESCRIPTION

[0030] The present application is further described in detail below with reference to the embodiments.

[0031] Preparation examples of raw materials and intermediates

[0032] raw material

[0033] The raw materials in the examples of this application can be obtained commercially:

[0034] Nylon 6 with a Shore hardness of 65D, J7013, Cangzhou Xuyang Chemical Co., Ltd.;

[0035] Nylon 6, 6510 with a Shore hardness of 70D, Cangzhou Xuyang Chemical Co., Ltd.

[0036] Nylon 12, L3000, Wanhua Chemical Group Co., Ltd.;

[0037] Antioxidant, antioxidant 1098;

[0038] Lubricant, methylsiloxane lubricant;

[0039] Polylaurolactam, analytical grade;

[0040] N-Benzoyl-laurolactam, analytical grade;

[0041] Nylon 6 prepolymer, polycaprolactam;

[0042] Nylon 12 prepolymer, polylaurolactam.

[0043] Preparation Example

[0044] Preparation Example 1

[0045] A block copolymer compatibilizer, the preparation method of which is as follows:

[0046] 1) Preparation of activator

[0047] ‌ 10 kg of polylaurolactam and 11 kg of N-benzoyl-laurolactam were reacted at 110°C for 2.5 hours under a nitrogen atmosphere. After cooling, the unreacted monomers were removed by vacuum drying to obtain an activator. The molecular weight of the polylaurolactam was 5000 g / mol.

[0048] ‌2) Block copolymer synthesis‌

[0049] 50 kg of nylon 6 prepolymer and 55 kg of nylon 12 prepolymer were uniformly mixed, and then 1.05 kg of the activator obtained in step 1) was added to obtain a mixture. The mixture was melt copolymerized at 250°C for 45 minutes to obtain a nylon 6-nylon 12 alternating block structure. The nylon 6 prepolymer was amino-terminated and had a molecular weight of 4000 g / mol. The nylon 12 prepolymer was carboxyl-terminated and had a molecular weight of 5000 g / mol.

[0050] ‌3) Post-processing and purification

[0051] The nylon 6-nylon 12 alternating block structure obtained in 2) is extruded into granules using a twin-screw extruder, water-cooled and then dried to remove unreacted homopolymer, thereby obtaining a block copolymer compatibilizer.

[0052] Preparation Example 2

[0053] A block copolymer compatibilizer, the preparation method of which is as follows:

[0054] 1) Preparation of activator

[0055] ‌ 10 kg of polylauryl lactam and 13 kg of N-benzoyl-lauryl lactam were reacted at 110°C for 2.5 hours under a protective nitrogen atmosphere. After cooling, the unreacted monomers were removed by vacuum drying to obtain an activator.‌

[0056] 2) Block copolymer synthesis

[0057] Same as Preparation Example 1;

[0058] ‌3) Post-processing and purification

[0059] Same as Preparation Example 1.

[0060] Preparation Example 3

[0061] A block copolymer compatibilizer, the preparation method of which is as follows:

[0062] 1) Preparation of activator

[0063] ‌ 10 kg of polylauryl lactam and 14 kg of N-benzoyl-lauryl lactam were reacted at 110°C for 2.5 hours under a protective nitrogen atmosphere. After cooling, the unreacted monomers were removed by vacuum drying to obtain an activator.‌

[0064] 2) Block copolymer synthesis

[0065] Same as Preparation Example 1;

[0066] ‌3) Post-processing and purification

[0067] Same as Preparation Example 1.

[0068] Preparation Example 4

[0069] A block copolymer compatibilizer, the preparation method of which is as follows:

[0070] 1) Preparation of activator

[0071] ‌ 10 kg of polylauryl lactam and 16 kg of N-benzoyl-lauryl lactam were reacted at 110°C for 2.5 hours under a protective nitrogen atmosphere. After cooling, the unreacted monomers were removed by vacuum drying to obtain an activator.‌

[0072] 2) Block copolymer synthesis

[0073] Same as Preparation Example 1;

[0074] ‌3) Post-processing and purification

[0075] Same as Preparation Example 1.

[0076] Preparation Example 5

[0077] A block copolymer compatibilizer, the preparation method of which is as follows:

[0078] 1) Preparation of activator

[0079] Same as Preparation Example 2;

[0080] 2) Block copolymer synthesis

[0081] 50 kg of nylon 6 prepolymer and 50 kg of nylon 12 prepolymer were uniformly mixed, and then 1 kg of the activator obtained in step 1) was added to obtain a mixture; the mixture was melt copolymerized at 250°C for 45 minutes to obtain a nylon 6-nylon 12 alternating block structure;

[0082] 3) Post-processing and purification

[0083] Same as Preparation Example 2.

[0084] Preparation Example 6

[0085] A block copolymer compatibilizer, the preparation method of which is as follows:

[0086] 1) Preparation of activator

[0087] Same as Preparation Example 2;

[0088] 2) Block copolymer synthesis

[0089] 50 kg of nylon 6 prepolymer and 60 kg of nylon 12 prepolymer were uniformly mixed, and then 1.1 kg of the activator obtained in step 1) was added to obtain a mixture; the mixture was melt copolymerized at 250°C for 45 minutes to obtain a nylon 6-nylon 12 alternating block structure;

[0090] 3) Post-processing and purification

[0091] Same as Preparation Example 2.

[0092] The mixture was melt copolymerized at 250°C for 45 minutes to obtain a nylon 6-nylon 12 alternating block structure;

[0093] 3) Post-processing and purification

[0094] Same as Preparation Example 2.

[0095] Preparation Example 7

[0096] A block copolymer compatibilizer, the preparation method of which is as follows:

[0097] 1) Preparation of activator

[0098] Same as Preparation Example 2;

[0099] 2) Block copolymer synthesis

[0100] 55 kg of nylon 6 prepolymer and 50 kg of nylon 12 prepolymer were uniformly mixed, and then 1.05 kg of the activator obtained in step 1) was added to obtain a mixture; the mixture was melt copolymerized at 250° C. for 45 minutes to obtain a nylon 6-nylon 12 alternating block structure;

[0101] 3) Post-processing and purification

[0102] Same as Preparation Example 2.

[0103] The mixture was melt copolymerized at 250°C for 45 minutes to obtain a nylon 6-nylon 12 alternating block structure;

[0104] 3) Post-processing and purification

[0105] Same as Preparation Example 2.

[0106] Example

[0107] Examples 1-3

[0108] A nylon sheath material for wires and cables, and a preparation method thereof is as follows:

[0109] According to the raw material ratio in Table 1, nylon 6 and nylon 12 are dried at 80°C, then mixed with the remaining other raw materials, and then melted and extruded into granules at an extrusion temperature of 225°C. After extrusion and granulation, they are dried to obtain nylon sheath materials for wires and cables.

[0110] Table 1 Raw material ratio table of Examples 1-3 (kg)

[0111]

[0112] Wherein, nylon 6 includes nylon 6 with a Shore hardness of 65D and nylon 6 with a Shore hardness of 70D, the weight ratio of nylon 6 with a Shore hardness of 65D to nylon 6 with a Shore hardness of 70D is 3:1, and the block copolymer compatibilizer comes from Preparation Example 1.

[0113] Example 4

[0114] Different from Example 2, in Example 4, the weight ratio of nylon 6 with a Shore hardness of 65D to nylon 6 with a Shore hardness of 70D is 2:1.

[0115] Example 5

[0116] Different from Example 2, in Example 4, the weight ratio of nylon 6 with a Shore hardness of 65D to nylon 6 with a Shore hardness of 70D is 4:1.

[0117] Example 6

[0118] Different from Example 2, in Example 4, the weight ratio of nylon 6 with a Shore hardness of 65D to nylon 6 with a Shore hardness of 70D is 1:3.

[0119] Example 7

[0120] Different from Example 2, in Example 7, an equal amount of nylon 6 with a Shore hardness of 65D is used to replace nylon 6 with a Shore hardness of 70D.

[0121] Example 8

[0122] Different from Example 2, in Example 7, an equal amount of nylon 6 with a Shore hardness of 70D is used to replace nylon 6 with a Shore hardness of 65D.

[0123] Examples 9-14

[0124] Different from Example 2, the block copolymer compatibilizers in Examples 9-14 are derived from Preparation Examples 2-7, respectively.

[0125] Comparative Example

[0126] Comparative Example 1

[0127] The difference from Example 1 is that in Comparative Example 1, an equal amount of nylon 6 is used to replace nylon 12.

[0128] Comparative Example 2

[0129] The difference from Example 1 is that in Comparative Example 2, an equal amount of nylon 12 is used to replace nylon 6.

[0130] Comparative Example 3

[0131] Different from Example 1, in Comparative Example 3, ethylene bisstearamide was used to replace the block copolymer compatibilizer.

[0132] Performance testing

[0133] The following performance tests were performed on the nylon sheath materials for wires and cables obtained in the examples and comparative examples. The test results are shown in Table 2.

[0134] The tensile properties were tested according to GB / T 1040.2-2022, with a specimen cross-section size of 10 mm × 4 mm and a tensile rate of 50 mm / min.

[0135] The impact performance was tested according to GB / T 1843-2008. The cross-sectional size of the milled V-notch spline was 8 mm × 4 mm, and an 11 J impact pendulum was used.

[0136] The bending performance was tested according to GB / T 9341-2008, with a test rate of 2 mm / min and a spline size of 10 mm × 4 mm × 80 mm. The bending performance test ended when the spline bending deformation reached 6 mm. The maximum force during the process was read and the bending strength was calculated.

[0137] Table 2 Performance test results

[0138]

[0139] Combining Examples 1-14 with Comparative Examples 1-3 and Table 2, it can be seen that the elongation at break, impact strength, and flexural strength of the materials obtained in Examples 1-13 are better than those in Comparative Examples 1 and 3. The elongation at break of the materials obtained in Examples 1-13 is lower than that in Comparative Example 2, but the impact strength and flexural strength of the material in Comparative Example 2 are lower than those in Example 1. This shows that the material obtained in the present application has better comprehensive performance in terms of elongation at break, impact strength, and flexural strength.

[0140] Combining Example 1 with Comparative Examples 1-2 and Table 2, it can be seen that the material obtained in Example 1 has better comprehensive performance in terms of elongation at break, impact strength, and flexural strength. This shows that the compounding of nylon 6 and nylon 12 can improve the comprehensive performance of the material in terms of elongation at break, impact strength, and flexural strength. This may be because nylon 6 and nylon 12 are compounded as base materials. After compounding, the molecular chains of the two are bonded through hydrogen bonds and van der Waals forces to form a rigid and flexible blend system; nylon 6 is a semi-crystalline material with high crystallinity, while nylon 12 has a lower degree of crystallinity. When the two are compounded, the crystalline region of nylon 6 can serve as a physical crosslinking point to enhance the rigidity of the material, while the amorphous region of nylon 12 provides elasticity, forming a microphase separation structure and improving impact resistance.

[0141] Combining Example 1 with Comparative Example 3 and Table 2, it can be seen that the material obtained in Example 1 has better comprehensive performance in terms of elongation at break, impact strength, and flexural strength. This shows that the compatibilizer obtained in the present application can improve the comprehensive performance of the material in terms of elongation at break, impact strength, and flexural strength. This may be because the compatibilizer molecular chain of the present application contains structural units of both PA6 and PA12, and the physical entanglement and chemical bonding between the molecular chains reduce the interfacial tension between the two phases, thereby reducing the phase separation size of the PA6 / PA12 blend from the micron level to the submicron level, significantly improving the compatibility of the two-phase molecules.

[0142] Combining Example 2 with Examples 4-8 and Table 2, it can be seen that the compounding systems of nylon 6 with different hardness have different effects on the mechanical properties of the composite material, among which the ratio in Example 2 is more optimal.

[0143] Combining Example 2 with Examples 9-14 and Table 2, it can be seen that the preparation of different PA6-PA12 block copolymers has different effects on the mechanical properties of the composite material, among which the ratio in Example 9 is more optimal.

[0144] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A nylon sheath material for wires and cables, characterized in that: Includes the following raw materials: nylon 6, nylon 12, block copolymer compatibilizer, antioxidant, lubricant; The preparation method of the block copolymer compatibilizer is: ‌1) Preparation of activating agent‌ Polylaurolactam and N-benzoyl-laurolactam are reacted at 100-120°C for 2-3 hours under a protective gas atmosphere, and then cooled and dried to remove unreacted monomers to obtain an activator; ‌2) Block copolymer synthesis‌ The nylon 6 prepolymer and the nylon 12 prepolymer are uniformly mixed, and then an activator is added to obtain a mixture; the mixture is melt copolymerized at 240-260°C for 30-60 minutes to obtain a nylon 6-nylon 12 alternating block structure; ‌3) Post-processing and purification The nylon 6-nylon 12 alternating block structure obtained in 2) is extruded into granules, water-cooled and then dried to remove unreacted homopolymer to obtain a block copolymer compatibilizer; The nylon 6 includes nylon 6 with a Shore hardness of 65D and nylon 6 with a Shore hardness of 70D, and the weight ratio of nylon 6 with a Shore hardness of 65D to nylon 6 with a Shore hardness of 70D is (2-4):

1.

2. The nylon sheath material for wires and cables according to claim 1, characterized in that: The weight ratio of the nylon 6 prepolymer to the nylon 12 prepolymer is 1:(1-1.2).

3. The nylon sheath material for wires and cables according to claim 1, characterized in that: The weight ratio of the polylaurolactam to N-benzoyl-laurolactam is 1:(1.1-1.4).

4. The nylon sheath material for wires and cables according to claim 1, characterized in that: The weight ratio of the nylon 6 prepolymer to the nylon 12 prepolymer and the activator is 100:(0.5-1.5).

5. The nylon sheath material for wires and cables according to claim 1, characterized in that: The weight ratio of nylon 6 to nylon 12 is 1:(1.5-3).

6. The nylon sheath material for wires and cables according to claim 1, characterized in that: The weight ratio of the nylon 6 to the nylon 12 and the block copolymer compatibilizer is 100:(3-7).

7. The nylon sheath material for wires and cables according to claim 1, characterized in that: The molecular weight of the polylaurolactam is 4000-6000 g / mol.

8. The nylon sheath material for wires and cables according to claim 1, characterized in that: The PA6 prepolymer is amino-terminated and has a molecular weight of 3000-5000 g / mol; the PA12 prepolymer is carboxyl-terminated and has a molecular weight of 4000-6000 g / mol.

9. A method for preparing a nylon sheath material for wires and cables according to any one of claims 1 to 8, characterized in that: The following steps are involved: Nylon 6 and nylon 12 are dried, mixed with the remaining other raw materials, melted, extruded and granulated at a temperature of 220-230°C, and dried after extrusion and granulation to obtain nylon sheath material for wires and cables.

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