Modified polyethylene, nylon optical cable co-extrusion sheath, co-extrusion die and preparation method

Abstract

The present application relates to a modified polyethylene, a nylon optical cable co-extrusion sheath, a co-extrusion die and a preparation method. The modified polyethylene comprises, by mass fraction, 86 to 88 parts of high-density polyethylene, 11.5 to 12.5 parts of a grafting agent, 0.05 to 0.2 parts of an antioxidant, 1 to 2 parts of a lubricant and 2.1 to 3.1 parts of carbon black. The density of the high-density polyethylene is 0.941 to 0.960 g / cm 3 The modified polyethylene provided in the embodiment of the present application is used as the inner sheath material of the co-extruded sheath of the nylon optical cable. The co-extruded sheath obtained by co-extrusion with the material of the nylon outer sheath can ensure that the modified polyethylene and nylon are tightly bonded, improve the bending performance of the optical cable using the nylon sheath, and reduce the risk of bending cracking during the construction process.

Description

Technical Field

[0001] The present application relates to the technical field of optical cable manufacturing, and in particular to a modified polyethylene and nylon optical cable co-extruded sheath, a co-extrusion die, and a preparation method. Background Art

[0002] Nylon sheath is a special optical cable sheath with the characteristics of anti-rat, anti-termite, high mechanical strength, heat resistance, wear resistance, oil resistance, weak acid resistance, good insulation, etc. It has a wide range of uses.

[0003] Nylon sheaths have high requirements for processing technology. In previous production and processing technologies, bubbles, wrinkles, and eccentricity often occur. In severe cases, they may break apart in the water tank after extrusion.

[0004] The bending performance of optical cables with nylon sheaths is poor, and they are not easy to bond with the inner sheath, and are prone to bending and cracking during construction. Summary of the Invention

[0005] The embodiments of the present application provide a modified polyethylene and nylon optical cable co-extruded sheath, a co-extrusion mold, and a preparation method to solve the problems in the related art where the optical cable using the nylon sheath has poor bending performance, is not easy to bond with the inner sheath, and is prone to bending and cracking during construction.

[0006] In the first aspect, a modified polyethylene is provided, which comprises, by mass fraction, 86 to 88 parts of high-density polyethylene, 11.5 to 12.5 parts of a grafting agent, 0.05 to 0.2 parts of an antioxidant, 1 to 2 parts of a lubricant and 2.1 to 3.1 parts of carbon black, wherein the density of the high-density polyethylene is 0.941 to 0.960 g / cm3.

[0007] In some embodiments, the grafting agent is maleic anhydride;

[0008] And / or, the antioxidant includes at least one of antioxidant 1010 and antioxidant DLTP;

[0009] And / or, the lubricant is polyethylene wax or oxidized polyethylene wax;

[0010] And / or, the carbon black is N330.

[0011] In a second aspect, a method for preparing the modified polyethylene as described above is provided, comprising the following steps:

[0012] After mixing high-density polyethylene, antioxidant, lubricant and carbon black, a grafting agent is added and kneaded;

[0013] The modified polyethylene is obtained by extrusion granulation and drying.

[0014] In some embodiments, the extrusion granulation temperature is 170° C. to 240° C., the drying temperature is 90° to 95° C., and the drying time is 1 to 2 hours.

[0015] In a third aspect, a nylon optical cable co-extruded sheath is provided, comprising:

[0016] An inner sheath, wherein the inner sheath is made of the modified polyethylene as described above;

[0017] A nylon outer sheath bonded to the outside of the inner sheath;

[0018] A color mark is provided on the surface of the nylon outer sheath.

[0019] In some embodiments, the nylon outer sheath is made of PA6 or PA12.

[0020] In some embodiments, the color standard is made by mixing PA12 and nylon masterbatch.

[0021] In some embodiments, the weight ratio of PA12 to nylon masterbatch is 20-30:1;

[0022] And / or, the nylon masterbatch is an anti-ultraviolet masterbatch.

[0023] In a fourth aspect, a method for preparing a co-extruded nylon optical cable sheath as described above is provided, comprising the following steps:

[0024] The raw materials of the inner sheath, the raw materials of the nylon outer sheath and the raw materials of the color code are co-extruded to obtain the nylon optical cable co-extruded sheath.

[0025] In some embodiments, before co-extrusion, it further comprises:

[0026] Heat the raw materials of the nylon outer sheath and the color code to 170℃~240℃;

[0027] Heat the raw material of the inner sheath to 170°C to 255°C.

[0028] In a fifth aspect, a co-extrusion die for a co-extruded nylon optical cable sheath is provided, comprising a die body, wherein the die body has an inner sheath flow channel formed along its axial direction, the inner sheath flow channel comprising a tapered section and a cylindrical section sequentially arranged along a raw material flow direction of the inner sheath;

[0029] A color mark flow channel is opened in the side wall of the mold body, one end of the color mark flow channel extends to the outer surface of the side wall of the mold body to form a color mark material hole for injecting the raw material of the color mark, and the other end extends to communicate with the cylindrical section;

[0030] A nylon outer sheath flow channel is also provided in the side wall of the mold body, and a circle of diversion holes is formed on the conical section along its circumference. The diversion holes are connected to one end of the nylon outer sheath flow channel, and the other end of the nylon outer sheath flow channel extends to the outer surface of the side wall of the mold body to form a nylon injection hole for injecting the raw material of the nylon outer sheath.

[0031] In some embodiments, the nylon outer sheath flow channel includes several levels of annular sub-flow channels distributed along the axial direction of the mold body, the first level annular sub-flow channel is connected to the nylon injection hole, the last level annular sub-flow channel is connected to the diversion hole, and the two adjacent levels of annular sub-flow channels are separated by a partition, and the partition is provided with an opening connecting the two adjacent levels of annular sub-flow channels, and the number of openings on each partition gradually increases from the first level annular sub-flow channel to the last level annular sub-flow channel.

[0032] In some embodiments, the distance from the bottom of the last-stage annular sub-channel to the center axis of the mold body is greater than the distance from the bottom of the annular sub-channel adjacent to the annular sub-channel to the center axis of the mold body, so that the opening connecting the last two stages of annular sub-channels forms an inclined ramp.

[0033] In some embodiments, a conical receiving ring is provided in the conical section, and a guide channel for guiding the raw material of the nylon outer sheath flowing out of the diversion hole to the cylindrical section is formed between the outer wall of the receiving ring and the inner wall of the conical section.

[0034] In some embodiments, the mold body includes:

[0035] A mold sleeve is provided with the color marking material hole and the nylon injection hole;

[0036] The mold cover is arranged in the mold sleeve. The mold cover is provided with the inner sheath flow channel and the color code flow channel. The nylon outer sheath flow channel is formed between the mold sleeve and the mold cover.

[0037] In some embodiments, a buffer step is formed on one side of the inner wall of the port where the color code flow channel communicates with the cylindrical section.

[0038] In a sixth aspect, a nylon optical cable is provided, comprising a nylon optical cable co-extruded sheath as described above, and a cable core arranged in the nylon optical cable co-extruded sheath.

[0039] The beneficial effects of the technical solution provided by this application include:

[0040] The embodiments of the present application provide a modified polyethylene, nylon optical cable co-extruded sheath, a co-extrusion mold and a preparation method. The modified polyethylene provided in the embodiments of the present application is used as the inner sheath material of the nylon optical cable co-extruded sheath, and the co-extruded sheath obtained by co-extrusion with the material of the nylon outer sheath can ensure that the modified polyethylene and the nylon are tightly bonded, thereby improving the bending performance of the optical cable using the nylon sheath and reducing the risk of bending and cracking during construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0042] Figure 1 A schematic diagram of a nylon optical cable provided in an embodiment of the present application;

[0043] Figure 2 Schematic diagram of the co-extrusion die provided in the embodiment of the present application;

[0044] Figure 3 for Figure 2 sectional view of ;

[0045] Figure 4 A schematic diagram of a mold cover provided in an embodiment of the present application;

[0046] Figure 5 for Figure 4 sectional view of ;

[0047] Figure 6 A schematic diagram of a buffer step provided in an embodiment of the present application;

[0048] Figure 7 This is a schematic diagram showing the principle of forming lines when there is no buffer step provided in an embodiment of the present application;

[0049] Figure 8 The principle diagram of the embodiment of the present application is provided in which no lines are formed when there is a buffer step.

[0050] In the figure: 1. Inner sheath; 2. Nylon outer sheath; 3. Color code; 4. Cable core; 5. Inner sheath flow channel; 6. Color code flow channel; 60. Color code material hole; 61. Buffer step; 7. Nylon outer sheath flow channel; 70. Nylon injection hole; 8. Diverter hole; 9. Partition; 90. Opening; 10. Receiving ring; 11. Guide channel; 12. Mold sleeve; 13. Mold cover; 14. Positioning pin. DETAILED DESCRIPTION

[0051] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0052] The present invention provides a modified polyethylene, which comprises, by mass fraction, 86 to 88 parts of high-density polyethylene, 11.5 to 12.5 parts of a grafting agent, 0.05 to 0.2 parts of an antioxidant, 1 to 2 parts of a lubricant, and 2.1 to 3.1 parts of carbon black, wherein the density of the high-density polyethylene is 0.941 to 0.960 g / cm 3 , is a highly crystalline, non-polar thermoplastic resin.

[0053] Among them, the grafting agent is maleic anhydride, the antioxidant includes at least one of antioxidant 1010 and antioxidant DLTP, the lubricant is polyethylene wax or oxidized polyethylene wax, and the carbon black is N330. Carbon black can absorb ultraviolet rays. When the carbon black aggregates and agglomerates dispersed in the plastic are irradiated with ultraviolet rays, it will cause ultraviolet scattering, and the scattered light is also absorbed by the carbon black aggregates and agglomerates, thereby significantly reducing the ultraviolet rays absorbed by the polymer. On the other hand, the oxygen-containing functional groups such as hydroxyl groups on the surface of the carbon black and the polymer are decomposed by ultraviolet rays to produce a polymer reaction, thereby playing a role in removing these groups and preventing further decomposition of the polymer.

[0054] The modified polyethylene can be prepared by the following preparation method:

[0055] 101: Pour high-density polyethylene, antioxidant, lubricant and carbon black into a kneading pot, rotate the mixing blade at a low speed to mix, then add the grafting agent into the kneading pot and knead. The meshing time is determined according to actual needs, such as 5 minutes.

[0056] 102: feeding the material, extruding the pellets through a double-stage extruder at a temperature of 170°C to 240°C, and drying the pellets at a temperature of 90°C to 95°C for 1 to 2 hours to obtain modified polyethylene.

[0057] The modified polyethylene provided in the embodiment of the present application is used as the inner sheath material of the co-extruded sheath of the nylon optical cable. The co-extruded sheath obtained by co-extrusion with the material of the nylon outer sheath can ensure that the modified polyethylene and the nylon are tightly bonded, thereby improving the bending performance of the optical cable using the nylon sheath and reducing the risk of bending and cracking during construction.

[0058] The nylon optical cable co-extruded sheath produced by co-extrusion of the modified polyethylene and nylon materials in this application was compared with the nylon optical cable sheath produced by the historical preparation process. It was found that there was a huge difference in the bonding strength between nylon and the modified polyethylene, as shown in the following table:

[0059]

[0060] Among them, Example 1: 86 parts of high-density polyethylene, 11.5 parts of grafting agent, 0.2 parts of antioxidant, 1.5 parts of lubricant and 2.8 parts of carbon black.

[0061] Example 2: 88 parts of high-density polyethylene, 12.5 parts of grafting agent, 0.1 part of antioxidant, 1.3 parts of lubricant and 2.2 parts of carbon black.

[0062] Example 3: 87 parts of high-density polyethylene, 12 parts of grafting agent, 0.05 parts of antioxidant, 1.9 parts of lubricant and 2.8 parts of carbon black.

[0063] Example 4: 86 parts of high-density polyethylene, 12 parts of grafting agent, 0.2 parts of antioxidant, 1.6 parts of lubricant and 3.1 parts of carbon black.

[0064] Example 5: 88 parts of high-density polyethylene, 11.5 parts of grafting agent, 0.18 parts of antioxidant, 1.4 parts of lubricant and 2.6 parts of carbon black.

[0065] Comparative Example 1: 100 parts of high-density polyethylene resin, 0.6 parts of crosslinking agent, 0.5 parts of antioxidant, 1.5 parts of lubricant and 2.6 parts of carbon black. The crosslinking agent is dicumyl peroxide.

[0066] Comparative Example 2: 90 parts of high-density polyethylene resin, 0.8 parts of antioxidant, 1.6 parts of lubricant and 2.4 parts of carbon black.

[0067] In the nylon optical cable co-extruded sheath made by co-extruding the modified polyethylene and nylon material of this application, the bonding strength between the nylon material and the modified polyethylene is 10.8-12.7N / mm 2 The bonding strength between nylon and modified polyethylene is greatly enhanced, which effectively ensures the bending cracking performance of the optical cable.

[0068] The nylon optical cable co-extruded sheath made by co-extrusion of the modified polyethylene and nylon material of the present application was compared with the nylon optical cable sheath prepared by the historical preparation process. After a 720-h xenon lamp aging test, it was found that the retention rate of the elongation at break of the nylon optical cable co-extruded sheath of the present application after aging was increased by 19%.

[0069] The reason why the modified polyethylene provided in the present application can have a high bonding strength with nylon materials is that polyethylene is a non-polar material, while nylon materials such as PA6 / PA12 are polar materials, and the two materials do not bond together. The modified polyethylene provided in the present application contains a maleic anhydride grafting agent, which contains both non-polar functional groups that bond to polyethylene and polar functional groups that bond to nylon materials such as PA6 / PA12, thereby ensuring that the polyethylene and nylon materials such as PA6 / PA12 are bonded together under the action of the grafting agent.

[0070] See also Figure 1 As shown, an embodiment of the present application also provides a nylon optical cable co-extruded sheath, which includes an inner sheath 1, a nylon outer sheath 2 and a color code 3. The inner sheath 1 adopts the modified polyethylene provided in the above embodiment, the nylon outer sheath 2 is bonded to the outside of the inner sheath 1, and the color code 3 is provided on the surface of the nylon outer sheath 2.

[0071] The nylon optical cable co-extruded sheath provided in the embodiment of the present application is obtained by co-extrusion of modified polyethylene and nylon, which can ensure that the modified polyethylene and nylon are tightly bonded, improve the bending performance of the optical cable using the nylon sheath, and reduce the risk of bending cracking during construction.

[0072] The nylon outer sheath 2 is made of PA6 or PA12. The color code 3 is made of a mixture of PA12 and nylon masterbatch. The nylon masterbatch imparts color to the color code. The ratio of PA12 to nylon masterbatch can be determined according to actual needs. For example, the weight ratio of PA12 to nylon masterbatch is 20 to 30:1. The nylon masterbatch can be UV-resistant. The use of anti-purple masterbatch ensures that the optical cable does not age or degrade under the influence of external light and heat, thereby ensuring the service life of the color code.

[0073] The present application also provides a method for preparing a nylon optical cable co-extruded sheath, which can be used to prepare the nylon optical cable co-extruded sheath mentioned in the above embodiment. Specifically, the preparation method includes the following steps:

[0074] Use the main extruder to process the modified polyethylene of the raw material of the inner sheath 1, use an auxiliary extruder to process the raw material of the nylon outer sheath 2, and use another auxiliary extruder to process the raw material of the color code 3. The three materials are co-extruded through a co-extrusion die at the head position to obtain a nylon optical cable co-extruded sheath.

[0075] During the auxiliary extruder processing, the raw materials of the nylon outer sheath 2 and the color code 3 are heated to 170°C to 240°C; during the main extruder processing, the raw materials of the inner sheath 1 are heated to 170°C to 255°C.

[0076] See also Figure 1As shown, an embodiment of the present application further provides a nylon optical cable, which includes the nylon optical cable co-extruded sheath provided in the above embodiment, and a cable core 4 provided in the nylon optical cable co-extruded sheath.

[0077] Obviously, the nylon optical cable has good bending performance and is not prone to bending and cracking during construction.

[0078] In order to facilitate the extrusion of the above-mentioned nylon optical cable co-extruded sheath, the embodiment of the present application also provides a co-extrusion die for the nylon optical cable co-extruded sheath, see Figure 2 、 Figure 3 、 Figure 4 and Figure 5 As shown, the co-extrusion die includes a die body, and the die body is provided with an inner jacket flow channel 5 along its axial direction. The inner jacket flow channel 5 includes a conical section and a cylindrical section arranged in sequence along the raw material flow direction of the inner jacket 1. The cone angle of the conical section is determined according to actual production needs. For example, as an example, it can be designed to be 40° to 50°, wherein Figure 3 The dotted arrow A indicates the flow direction of the raw material modified polyethylene of the inner sheath 1 .

[0079] A color mark flow channel 6 is opened in the side wall of the mold body. One end of the color mark flow channel 6 extends to the outer surface of the side wall of the mold body to form a color mark material hole 60, and the other end extends to communicate with the cylindrical section; the color mark material hole 60 is used to inject the raw material of the color mark 3. Figure 3 The dotted arrow B in the middle is the flow direction of the raw material of color code 3.

[0080] A nylon outer sheath flow channel 7 is also provided in the side wall of the mold body. A circle of diverter holes 8 are formed along the circumference of the tapered section. The diverter holes 8 are evenly distributed. The diverter holes 8 are connected to one end of the nylon outer sheath flow channel 7. The other end of the nylon outer sheath flow channel 7 extends to the outer surface of the side wall of the mold body to form a nylon injection hole 70. The nylon injection hole 70 is used to inject the raw material of the nylon outer sheath 2. Figure 3 The dotted arrow C indicates the flow direction of the raw material of the nylon outer sheath 2 .

[0081] The arrangement positions of the color marking material hole 60 and the nylon injection hole 70 on the side wall of the mold body can be determined according to actual needs, such as Figure 3 In the figure, the color marking material hole 60 and the nylon material injection hole 70 are arranged symmetrically at 180 degrees. The advantage of the symmetrical arrangement of the material injection holes is that the stability of the co-extrusion mold can be ensured as much as possible during injection.

[0082] Since the nylon outer sheath 2 is bonded to the surface of the inner sheath 1, when the raw material of the nylon outer sheath 2 flows into the nylon outer sheath flow channel 7 to wrap around the surface of the inner sheath 1 and is co-extruded to form the nylon outer sheath 2, in order to make the nylon outer sheath 2 as thick as possible, it is necessary to ensure that the raw material flowing out of each diversion hole 8 is uniform. To this end, in some preferred embodiments, a multi-stage flow channel is designed to achieve uniform diversion. Specifically, see Figure 3 and Figure 4 As shown, the nylon outer sheath flow channel 7 includes several levels of annular sub-flow channels distributed along the axial direction of the mold body. The first level annular sub-flow channel is connected to the nylon injection hole 70, and the last level annular sub-flow channel is connected to the diversion hole 8. The two adjacent levels of annular sub-flow channels are separated by a partition 9. The partition 9 is provided with an opening 90 connecting the two adjacent levels of annular sub-flow channels, and the number of openings 90 on each partition 9 gradually increases from the first level annular sub-flow channel to the last level annular sub-flow channel.

[0083] In this embodiment, to ensure uniform material flow, multiple annular sub-channels are designed. These annular sub-channels are separated by partitions 9, each of which has openings 90. The openings 90 form multiple sub-plates. From the first to the last annular sub-channel, the number of openings 90 on each partition 9 gradually increases, resulting in a gradually increasing number of sub-plates formed by each partition 9. For example, in a five-stage annular sub-channel structured by four partitions 9, the first partition 9 has 1 to 2 sub-plates, the second has 3 to 4 sub-plates, the third has 6 to 8 sub-plates, and the fourth has 12 to 16 sub-plates. The greater the number of sub-plates in a partition 9, the greater the number of openings 90 on the partition 9, and the smaller the width of the openings 90. Consequently, through layer-by-layer diversion, the material flow is evenly distributed, ultimately passing through the diversion holes 8 and entering the inner jacket channel 5.

[0084] To further ensure uniform material flow, see Figure 5 As shown, the distance from the bottom of the last-stage annular sub-channel to the center axis of the mold body is greater than the distance from the bottom of the annular sub-channel adjacent to the annular sub-channel to the center axis of the mold body, so that the opening 90 connecting the last two stages of annular sub-channels forms an inclined ramp, and the inclination angle α of the ramp can be designed according to actual needs.

[0085] Since the last-stage annular sub-channel is directly connected to the diverter holes 8 arranged in a circle, the raw material entering the last-stage annular sub-channel passes through the diverter holes 8 and directly enters the inner sheath channel 5, and is extruded on the surface of the inner sheath 1 to form a nylon outer sheath 2. After the raw material of the nylon outer sheath 2 enters the last-stage annular sub-channel, if the above-mentioned ramp is not designed, then under the action of inertia and gravity, the raw material that enters the penultimate annular sub-channel first can easily enter the last-stage annular sub-channel first, and then enter the diverter holes 8. The raw material that enters the penultimate annular sub-channel later can then enter the last-stage annular sub-channel, which will cause the problem of uneven material flow.

[0086] After designing the above-mentioned ramp, even if the raw material that first enters the penultimate annular sub-channel wants to enter the last annular sub-channel under the action of inertia, the existence of the ramp, combined with the gravity of the raw material, can play a certain buffering role, so that the raw materials that enter the penultimate annular sub-channel before and after can enter the last annular sub-channel together under the push of the subsequent raw materials, thereby improving the problem of uneven material flow.

[0087] See also Figure 3 and Figure 5 As shown, a conical receiving ring 10 is provided in the conical section, and a guide channel 11 for guiding the raw material of the nylon outer sheath 2 flowing out of the diversion hole 8 to the cylindrical section is formed between the outer wall of the receiving ring 10 and the inner wall of the conical section.

[0088] The raw material of the nylon outer sheath 2 first flows through the first baffle 9. After being divided by the first baffle 9, the material reaches the second baffle 9, and so on, finally entering the final annular sub-flow channel, thereby achieving uniform distribution of the raw material. After being divided by the baffle 9, the raw material of the nylon outer sheath 2 is divided into smaller streams through the diversion holes 8 and falls onto the receiving ring 10, forming a nylon annular flow evenly distributed on the circumferential cross-section.

[0089] See also Figure 2 、 Figure 3 、 Figure 4 and Figure 5 As shown, the mold body includes a mold sleeve 12 and a mold cover 13. The mold sleeve 12 is provided with a color marking material hole 60 and a nylon injection hole 70. The mold cover 13 is arranged in the mold sleeve 12. The mold cover 13 is provided with an inner sheath flow channel 5 and a color marking flow channel 6. A nylon outer sheath flow channel 7 is formed between the mold sleeve 12 and the mold cover 13.

[0090] The mold body is divided into a mold sleeve 12 and a mold cover 13 to facilitate the production, processing and molding of the mold.

[0091] See also Figure 4 As shown, the mold cover 13 is further provided with a positioning pin 14 to facilitate the installation and positioning of the mold cover 13.

[0092] To avoid lines on the color mark 3 caused by the material of the nylon outer sheath 2, see Figure 3 and Figure 6 As shown, a buffer step 61 is formed on one side of the inner wall of the port where the color code flow channel 6 communicates with the cylindrical section.

[0093] See also Figure 7 and Figure 8 As shown, when there is no buffer step 61, the raw material of the color mark 3 flows along the direction B, and after merging with the raw material of the nylon outer sheath 2 flowing along the direction A, due to the vertical merging, the raw material of the color mark 3 will form turbulence in the raw material of the nylon outer sheath 2, and then appear on the color mark 3. Figure 7 The lines in the dotted oval block affect product identification. However, when the buffer step 61 is designed, the raw material of the color mark 3 will change its flow direction due to the buffer step 61, so that the raw material of the color mark 3 flows along the raw material of the nylon outer sheath 2 and merges with the raw material of the nylon outer sheath 2, thereby forming a color mark 3 without lines on the surface of the nylon outer sheath 2.

[0094] In the description of this application, it should be noted that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0095] It should be noted that, in this application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0096] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A co-extrusion die for a nylon optical cable co-extrusion sheath, characterized in that: It comprises a mold body, wherein the mold body is provided with an inner jacket flow channel (5) along its axial direction, and the inner jacket flow channel (5) comprises a conical section and a cylindrical section arranged in sequence along the raw material flow direction of the inner jacket (1); A color mark flow channel (6) is provided in the side wall of the mold body, one end of the color mark flow channel (6) extends to the outer surface of the side wall of the mold body to form a color mark material hole (60) for injecting raw materials of the color mark (3), and the other end extends to communicate with the cylindrical section; A nylon outer sheath flow channel (7) is also provided in the side wall of the mold body, and a circle of diversion holes (8) are formed on the conical section along its circumference, wherein the diversion holes (8) are connected to one end of the nylon outer sheath flow channel (7), and the other end of the nylon outer sheath flow channel (7) extends to the outer surface of the side wall of the mold body to form a nylon injection hole (70) for injecting raw materials of the nylon outer sheath (2); The nylon outer jacket flow channel (7) includes a plurality of annular sub-flow channels distributed along the axial direction of the mold body, the first annular sub-flow channel is connected to the nylon injection hole (70), the last annular sub-flow channel is connected to the diversion hole (8), and the adjacent two annular sub-flow channels are separated by a partition (9), and the partition (9) is provided with an opening (90) for connecting the adjacent two annular sub-flow channels, and the number of openings (90) on each partition (9) gradually increases from the first annular sub-flow channel to the last annular sub-flow channel, and the direction from the first annular sub-flow channel to the last annular sub-flow channel is opposite to the flow direction of the raw material of the inner jacket (1); The distance between the bottom of the last-stage annular sub-flow channel and the center axis of the mold body is greater than the distance between the bottom of the annular sub-flow channel adjacent to the annular sub-flow channel and the center axis of the mold body, so that the opening (90) connecting the last two stages of annular sub-flow channels forms an inclined ramp.

2. The co-extrusion die for the co-extrusion sheath of nylon optical cable according to claim 1, characterized in that: A conical receiving ring (10) is provided in the conical section, and a guide channel (11) for guiding the raw material of the nylon outer sheath (2) flowing out of the diversion hole (8) to the cylindrical section is formed between the outer wall of the receiving ring (10) and the inner wall of the conical section.

3. The co-extrusion die for the co-extrusion sheath of nylon optical cable according to claim 1, characterized in that: The mold body comprises: A mold sleeve (12) is provided with the color marking material hole (60) and the nylon injection hole (70); A mold cover (13) is provided in the mold sleeve (12); the mold cover (13) is provided with the inner sheath flow channel (5) and the color code flow channel (6); and the nylon outer sheath flow channel (7) is formed between the mold sleeve (12) and the mold cover (13).

4. The co-extrusion die for the co-extrusion sheath of nylon optical cable according to claim 1, characterized in that: A buffer step (61) is formed on one side of the inner wall of the port where the color code flow channel (6) communicates with the cylindrical section.

5. The co-extrusion die for the co-extrusion sheath of nylon optical cable according to claim 1, characterized in that: The nylon optical cable co-extruded sheath comprises: An inner sheath (1), wherein the inner sheath (1) is made of modified polyethylene; A nylon outer sheath (2), wherein the nylon outer sheath (2) is bonded to the outside of the inner sheath (1); A color mark (3), the color mark (3) being provided on the surface of the nylon outer sheath (2); The modified polyethylene comprises, by mass fraction, 86 to 88 parts of high-density polyethylene, 11.5 to 12.5 parts of a grafting agent, 0.05 to 0.2 parts of an antioxidant, 1 to 2 parts of a lubricant, and 2.1 to 3.1 parts of carbon black, wherein the density of the high-density polyethylene is 0.941 to 0.960 g / cm 3 .

6. The co-extrusion die for the co-extrusion sheath of nylon optical cable according to claim 5, characterized in that: The nylon outer sheath (2) is made of PA6 or PA12.

7. The co-extrusion die for the co-extrusion sheath of nylon optical cable according to claim 5, characterized in that: The color standard (3) is made by mixing PA12 and nylon masterbatch.

8. The co-extrusion die for the co-extrusion sheath of nylon optical cable according to claim 7, characterized in that: The weight ratio of PA12 and nylon masterbatch is 20~30:1; And / or, the nylon masterbatch is an anti-ultraviolet masterbatch.

9. The co-extrusion die for the co-extrusion sheath of nylon optical cable according to any one of claims 5 to 8, characterized in that: The preparation method of the nylon optical cable co-extrusion sheath comprises the following steps: The raw material of the inner sheath (1), the raw material of the nylon outer sheath (2) and the raw material of the color code (3) are co-extruded to obtain the nylon optical cable co-extruded sheath.

10. The co-extrusion die for the co-extrusion sheath of nylon optical cable according to claim 9, characterized in that: Before co-extrusion, it also includes: Heat the raw material of the nylon outer sheath (2) and the raw material of the color mark (3) to 170°C to 240°C; The raw material of the inner sheath (1) is heated to 170°C~255°C.

11. The co-extrusion die for the co-extrusion sheath of nylon optical cable according to claim 5, characterized in that: The grafting agent is maleic anhydride; And / or, the antioxidant includes at least one of antioxidant 1010 and antioxidant DLTP; And / or, the lubricant is polyethylene wax or oxidized polyethylene wax; And / or, the carbon black is N330.

12. The co-extrusion die for the co-extrusion sheath of nylon optical cable according to claim 5, characterized in that: The preparation method of the modified polyethylene comprises the following steps: After mixing high-density polyethylene, antioxidant, lubricant and carbon black, a grafting agent is added and kneaded; The modified polyethylene is obtained by extrusion granulation and drying.

13. The co-extrusion die for the co-extrusion sheath of nylon optical cable according to claim 12, characterized in that: The temperature of extrusion granulation is 170℃~240℃, the drying temperature is 90℃~95℃, and the drying time is 1~2h.

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