Nylon sheath material for wires and cables and preparation method of nylon sheath material

Abstract

The invention relates to the field of cable materials, in particular to a nylon sheath material for wires and cables, which comprises nylon 6, nylon 12, a block copolymer compatilizer, an antioxidant and a lubricant. The preparation method of the block copolymer compatilizer comprises the following steps: 1) reacting polylaurolactam with N-benzoyl-laurolactam for 2-3 hours at 100-120 DEG C in a protective gas atmosphere, cooling, and drying to remove unreacted monomers, so as to obtain an activating agent; 2) uniformly mixing the nylon 6 prepolymer and the nylon 12 prepolymer, and adding an activating agent to obtain a mixture; the mixture is subjected to melt copolymerization for 30-60 min at the temperature of 240-260 DEG C, and a nylon 6-nylon 12 alternating block structure is obtained; and 3) carrying out extrusion granulation on the nylon 6-nylon 12 alternate block structure obtained in the step 2), carrying out water cooling, drying, and removing the unreacted homopolymer to obtain the block copolymer compatibilizer. The obtained material has excellent comprehensive properties such as elongation at break, impact strength and bending strength.

Description

Technical Field

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

[0002] Wire and cable is a carrier for transmitting signals and is an aggregate composed of the following parts: one or more insulated wire cores, and their respective possible coating layers, a total protective layer, and an outer sheath.

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

[0004] There are various types of wire and cable. Some wire and cable need to be wound or coiled during use, so it is required that the nylon sheath material must have excellent elongation at break and good non-notch or notch impact strength. The dimensional stability of nylon is poor, and the non-notch or notch impact strength is low in the dry state and low-temperature environment. In this regard, the method usually adopted by researchers is to add a toughening agent. For example, Chinese Patent No. 201010617355.7 discloses a toughened nylon blend and a preparation method thereof. The toughening agent is prepared by graft modification of a blend of ethylene-1-octene copolymer (POE), polypropylene (PP), and ethylene acrylic 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 nylon itself, greatly expanding the application range of nylon.

[0005] In view of the above related technologies, the applicant found that its elongation at break cannot meet the requirements under some winding conditions and needs to be further improved. Summary of the Invention

[0006] In order to improve the elongation at break of the nylon sheath material for wire and cable, the present application provides a nylon sheath material for wire and cable and a preparation method thereof.

[0007] In the first aspect, the present application provides a nylon sheath material for wire and cable, adopting the following technical solution.

[0008] A nylon sheath material for wire and cable, comprising the following raw materials: nylon 6, nylon 12, block copolymer compatibilizer, antioxidant, lubricant; The preparation method of the block copolymer compatibilizer is as follows: 1) Preparation of activator 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; 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 homopolymers, thereby obtaining a block copolymer compatibilizer.

[0009] 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, and nylon 12 has low crystallinity. When the two are compounded, the crystalline region of nylon 6 can be used as a physical cross-linking point to enhance the rigidity of the material, and the amorphous region of nylon 12 provides elasticity, forming a microscopic phase separation structure and improving impact resistance.

[0010] However, nylon 6 and nylon 12 are incompatible at the molecular level, which will result in poor mechanical properties of the composite material. This application uses an activator to trigger block copolymerization, combines acid hydrolysis reaction to optimize the molecular structure, and efficiently prepares PA6-PA12 block copolymers, whose molecular chains contain 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, and the phase separation size of the PA6 / PA12 blend is reduced from the micron level to the submicron level, significantly improving the compatibility of the two-phase molecules. Improve the elongation at break, impact strength and flexural strength of the material.

[0011] Furthermore, the weight ratio of the nylon 6 prepolymer to the nylon 12 prepolymer is 1:(1-1.2).

[0012] Furthermore, the weight ratio of the polylaurolactam to N-benzoyl-laurolactam is 1:(1.1-1.4).

[0013] Furthermore, the weight ratio of the nylon 6 prepolymer to the nylon 7 prepolymer and the activator is 100:(0.5-1.5).

[0014] Furthermore, the weight ratio of nylon 6 to nylon 12 is 1:(1.5-3).

[0015] Furthermore, the weight ratio of the sum of the nylon and nylon 7 to the weight of the block copolymer compatibilizer is 100:(3 - 7).

[0016] 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.

[0017] Furthermore, the molecular weight of the polylauryl lactam is 4000 - 6000 g / mol.

[0018] Furthermore, the nylon 6 prepolymer is of the amino - terminated type with a molecular weight of 3000 - 5000 g / mol; the nylon 12 prepolymer is of the carboxyl - terminated type with a molecular weight of 4000 - 6000 g / mol.

[0019] In a second aspect, the present application provides a preparation method of a nylon sheath material for wire and cable, adopting the following technical solution.

[0020] Dry the nylon 6 and nylon 12, then mix with the remaining other raw materials, and then carry out melting and extrusion granulation. The extrusion temperature is 220 - 230 °C. After extrusion granulation, dry it to obtain the nylon sheath material for wire and cable.

[0021] In summary, the present application has the following beneficial effects: In the present application, nylon 6 and nylon 12 are compounded as the base material, and a PA6 - PA12 block copolymer is used as the compatibilizer. Its molecular chain contains the structural units of both PA6 and PA12 at the same time. By physical entanglement and chemical bonding between molecular chains, the interfacial tension between the two phases is reduced, and the phase separation size of the PA6 / PA12 blend is reduced from the micron level to the sub - micron level, significantly improving the molecular compatibility between the two phases 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 blend system with both rigidity and flexibility; nylon 6 is a semi - crystalline material with a high crystallinity, and the crystallinity of nylon 12 is relatively low. When the two are compounded, the crystal regions of nylon 6 can serve as physical cross - linking points to enhance the rigidity of the material, and the amorphous regions of nylon 12 provide elasticity, forming a micro - phase separation structure and improving the impact resistance. The obtained material has an elongation at break that can reach 375% and an impact strength that can reach 92 kJ·m 2 and a flexural strength that can reach 38 MPa. Specific Embodiments

[0022] The following further elaborates on the present application with reference to examples.

[0023] Preparation Examples of Raw Materials and Intermediates Raw Materials The raw materials in the examples of the present application can all be obtained commercially: Nylon 6 with a Shore hardness of 65D, J7013, Cangzhou Xuyang Chemical Co., Ltd.; Nylon 6 with a Shore hardness of 70D, 6510, Cangzhou Xuyang Chemical Co., Ltd.; Nylon 12, L3000, Wanhua Chemical Group Co., Ltd.; Antioxidant, antioxidant 1098; Lubricant, polydimethylsiloxane lubricant; Polylauryl lactam, analytical pure; N-Benzoyl-lauryl lactam, analytical pure; Nylon 6 prepolymer, polycaprolactam; Nylon 12 prepolymer, polylauryl lactam.

[0024] Preparation Example Preparation Example 1 A block copolymer compatibilizer, and its preparation method is as follows: 1) Preparation of activator Mix 10 kg of polylauryl lactam with 11 kg of N-benzoyl-lauryl lactam, react at 110 °C for 2.5 h under a protective gas nitrogen atmosphere, and after cooling, vacuum dry to remove unreacted monomers to obtain the activator; the molecular weight of polylauryl lactam is 5000 g / mol; 2) Synthesis of block copolymer Mix 50 kg of nylon 6 prepolymer and 55 kg of nylon 12 prepolymer evenly, then add 1.05 kg of the activator obtained in step 1) to obtain a mixture; melt copolymerize the mixture at 250 °C for 45 min to obtain a nylon 6-nylon 12 alternating block structure; the nylon 6 prepolymer is of the amino-terminated type with a molecular weight of 4000 g / mol; the nylon 12 prepolymer is of the carboxyl-terminated type with a molecular weight of 5000 g / mol; 3) Post-treatment and purification Extrude and pelletize the nylon 6-nylon 12 alternating block structure obtained in 2) with a twin-screw extruder, cool with water and then dry to remove unreacted homopolymers to obtain the block copolymer compatibilizer.

[0025] Preparation Example 2 A block copolymer compatibilizer, and its preparation method is as follows: 1) Preparation of activator Mix 10 kg of polylauryl lactam with 13 kg of N-benzoyl-lauryl lactam, react at 110 °C for 2.5 h under a protective gas nitrogen atmosphere, and after cooling, vacuum dry to remove unreacted monomers to obtain the activator; 2) Synthesis of block copolymer Same as Preparation Example 1; 3) Post-treatment and purification Same as Preparation Example 1.

[0026] Preparation Example 3 A block copolymer compatibilizer, and its preparation method is as follows: 1) Preparation of activator 10 kg of poly(dodecanolactam) and 14 kg of N-benzoyl-dodecanolactam are reacted at 110 °C for 2.5 h under a nitrogen atmosphere of protective gas, and after cooling, unreacted monomers are removed by vacuum drying to obtain an activator; 2) Synthesis of block copolymer Same as Preparation Example 1; 3) Post-treatment and purification Same as Preparation Example 1.

[0027] Preparation Example 4 A block copolymer compatibilizer, and its preparation method is as follows: 1) Preparation of activator 10 kg of poly(dodecanolactam) and 16 kg of N-benzoyl-dodecanolactam are reacted at 110 °C for 2.5 h under a nitrogen atmosphere of protective gas, and after cooling, unreacted monomers are removed by vacuum drying to obtain an activator; 2) Synthesis of block copolymer Same as Preparation Example 1; 3) Post-treatment and purification Same as Preparation Example 1.

[0028] Preparation Example 5 A block copolymer compatibilizer, and its preparation method is as follows: 1) Preparation of activator Same as Preparation Example 2; 2) Synthesis of block copolymer 50 kg of nylon 6 prepolymer and 50 kg of nylon 12 prepolymer are mixed evenly, and then 1 kg of the activator obtained in step 1) is added to obtain a mixture; the mixture is melt copolymerized at 250 °C for 45 min to obtain a nylon 6-nylon 12 alternating block structure; 3) Post-treatment and purification Same as Preparation Example 2.

[0029] Preparation Example 6 A block copolymer compatibilizer, and its preparation method is as follows: 1) Preparation of activator Same as Preparation Example 2; 2) Synthesis of block copolymer 50 kg of nylon 6 prepolymer and 60 kg of nylon 12 prepolymer were mixed evenly, 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; 3) Post-processing and purification Same as Preparation Example 2.

[0030] The mixture was melt copolymerized at 250°C for 45 minutes to obtain a nylon 6-nylon 12 alternating block structure; 3) Post-processing and purification Same as Preparation Example 2.

[0031] Preparation Example 7 A block copolymer compatibilizer, the preparation method of which is as follows: 1) Preparation of activating agent Same as Preparation Example 2; 2) Block copolymer synthesis 55 kg of nylon 6 prepolymer and 50 kg of nylon 12 prepolymer were mixed evenly, 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; 3) Post-processing and purification Same as Preparation Example 2.

[0032] The mixture was melt copolymerized at 250°C for 45 minutes to obtain a nylon 6-nylon 12 alternating block structure; 3) Post-processing and purification Same as Preparation Example 2.

[0033] Example Examples 1-3 A nylon sheath material for electric wires and cables, and a preparation method thereof is as follows: 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 granulation, they are dried to obtain nylon sheath materials for wires and cables.

[0034] Table 1 Raw material ratio table of Examples 1-3 (kg)

[0035] 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 and nylon 6 with a Shore hardness of 70D is 3:1, and the block copolymer compatibilizer comes from Preparation Example 1.

[0036] Example 4 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.

[0037] Example 5 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.

[0038] Example 6 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.

[0039] Example 7 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.

[0040] Example 8 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.

[0041] Examples 9 - 14 Different from Example 2, in Examples 9 - 14, the block copolymer compatibilizers are respectively from Preparation Examples 2 - 7.

[0042] Comparative Example Comparative Example 1 Different from Example 1, in Comparative Example 1, an equal amount of nylon 6 is used to replace nylon 12.

[0043] Comparative Example 2 Different from Example 1, in Comparative Example 2, an equal amount of nylon 12 is used to replace nylon 6.

[0044] Comparative Example 3 Different from Example 1, in Comparative Example 3, ethylene bisstearamide is used to replace the block copolymer compatibilizer.

[0045] Performance Testing The following performance tests were carried out on the nylon sheath materials for wire and cable obtained in the examples and comparative examples, and the test results are shown in Table 2.

[0046] The tensile properties were tested in accordance with GB / T 1040.2 - 2022. The cross-sectional dimensions of the specimen were 10 mm × 4 mm, and the tensile rate was 50 mm / min.

[0047] The impact properties were tested in accordance with GB / T 1843 - 2008. The cross-sectional dimensions of the milled V-notch specimen were 8 mm × 4 mm, and an impact pendulum of 11 J was used.

[0048] The flexural property was tested in accordance with GB / T 9341-2008 at a test rate of 2 mm / min. The dimensions of the specimen were 10 mm×4 mm×80 mm. When the flexural deformation of the specimen reached 6 mm, the flexural property test was completed, and the maximum force during the process was read and the flexural strength was calculated.

[0049] Table 2 Results of Performance Detection

[0050] Combining Examples 1-14 and Comparative Examples 1-3 and referring to 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 all superior to those of Comparative Example 1 and Comparative Example 3. Among them, the elongation at break of the materials obtained in Examples 1-13 is lower than that of Comparative Example 2, but the impact strength and flexural strength of the materials in Comparative Example 2 are lower than those in Example 1. This shows that the materials obtained in this application have better comprehensive performance in terms of elongation at break, impact strength, and flexural strength.

[0051] Combining Example 1 and Comparative Examples 1-2 and referring to Table 2, it can be seen that the materials obtained in Example 1 have better comprehensive performance in terms of elongation at break, impact strength, and flexural strength. This shows that the blending of nylon 6 and nylon 12 can improve the comprehensive performance of the elongation at break, impact strength, and flexural strength of the materials. This may be because the molecular chains of nylon 6 and nylon 12 are combined through hydrogen bonds and van der Waals forces as the base material after blending, forming a blend system with both rigidity and flexibility; nylon 6 is a semi-crystalline material with a high degree of crystallinity, and the crystallinity of nylon 12 is relatively low. When the two are blended, the crystal regions of nylon 6 can act as physical cross-linking points to enhance the rigidity of the material, while the amorphous regions of nylon 12 provide elasticity, forming a micro-phase separation structure and improving the impact resistance.

[0052] Combining Example 1 and Comparative Example 3 and referring to Table 2, it can be seen that the materials obtained in Example 1 have better comprehensive performance in terms of elongation at break, impact strength, and flexural strength. This shows that the compatibilizer obtained in this application can improve the comprehensive performance of the elongation at break, impact strength, and flexural strength of the materials. This may be because the molecular chains of the compatibilizer in this application contain structural units of both PA6 and PA12 at the same time, reducing the interfacial tension between the two phases through physical entanglement and chemical bonding between the molecular chains, and reducing the phase separation size of the PA6 / PA12 blend from the micron level to the sub-micron level, significantly improving the molecular compatibility between the two phases.

[0053] Combining Example 2 and Examples 4-8 and referring to Table 2, it can be seen that the blending systems of nylon 6 with different hardnesses have different effects on the mechanical properties of the composite materials, and the ratio in Example 2 is more optimal.

[0054] Combining Example 2 with Examples 9-14 and referring to Table 2, it can be seen that preparing different PA6-PA12 block copolymers has different effects on the mechanical properties of the composites, and the ratio in Example 9 is more optimal.

[0055] This specific embodiment is only an interpretation of the present application and does not limit the present application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions 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 2-3h under a protective gas atmosphere, and then 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 homopolymers, thereby obtaining a block copolymer compatibilizer.

2. A 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. A 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 7 prepolymer and the activator is 100:(0.5-1.5).

5. The nylon sheath material for electric 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 wire and cable according to claim 1, characterized in that: The weight ratio of the nylon to nylon 7 and the block copolymer compatibilizer is 100:(3-7).

7. The nylon sheath material for electric wires and cables according to claim 1, characterized in that: 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.

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

9. The nylon sheath material for electric wires and cables according to claim 1, characterized in that: 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.

10. A method for preparing a nylon sheath material for electric wires and cables as claimed in any one of claims 1 to 9, characterized in that: The following steps are involved: Nylon 6 and nylon 12 are dried, and then mixed with other remaining raw materials, and then melted and extruded into granules at an extrusion temperature of 220-230°C. After extrusion granulation, they are dried to obtain nylon sheath materials for wires and cables.

Images