CN114381085B

CN114381085B - Preparation method of ultralow friction coefficient central tube type air-blown micro cable and sheath thereof

Info

Publication number: CN114381085B
Application number: CN202111360416.0A
Authority: CN
Inventors: 阮云芳; ***; 杨向荣; 王佳; 詹浩; 祁林; 肖毅; 郑磊; 王俊
Original assignee: Yangtze Optical Fibre and Cable Co Ltd
Current assignee: Yangtze Optical Fibre and Cable Co Ltd
Priority date: 2021-11-17
Filing date: 2021-11-17
Publication date: 2024-01-09
Anticipated expiration: 2041-11-17
Also published as: CN114381085A

Abstract

The invention discloses a center tube type air-blowing micro cable with an ultralow friction coefficient, which comprises a sheath, wherein a mixture for preparing the sheath mainly comprises, by mass, 85-95 parts of polyoxymethylene, 3-13 parts of molybdenum disulfide, a compatilizer, an antioxidant, an aldehyde absorbing agent and a light shielding agent. The invention adopts the materials such as polyformaldehyde, molybdenum disulfide, compatilizer, antioxidant, aldehyde absorbing agent and the like to prepare the sheath, thereby greatly reducing the friction coefficient of the surface of the central tube type air-blowing micro-cable, greatly reducing the fluctuation range of the air-blowing friction coefficient and greatly improving the air-blowing distance and the construction efficiency of the product. The invention has stable environmental resistance, especially when used in low temperature environment, the attenuation of the optical fiber basically has no change, thus ensuring the stable transmission performance of the optical fiber. The invention can be laid in a plastic air-blowing microtube for communication with the distance of 5/3.5mm or smaller in an air-blowing manner at a larger distance, thereby meeting the problems of customer air-blowing effect and construction efficiency.

Description

Preparation method of ultralow friction coefficient central tube type air-blown micro cable and sheath thereof

Technical Field

The invention belongs to the field of optical cables, and particularly relates to a preparation method of a central tube type air-blown micro cable with an ultralow friction coefficient and a sheath thereof.

Background

Because of construction standardization, mechanization and high efficiency, the air-blown optical cable laying technology is widely applied to the 5G network construction process at home and abroad at present, particularly in the FTTH network construction process, a communication air-blown plastic microtube used by a pipeline operator is basically a bundling tube with the diameter of 5/3.5mm (the outer diameter is 5mm, the inner diameter is 3.5 mm), air-blown optical cable products used in the pipeline are almost all air-blown optical fiber units with the diameter of basically less than 1.6mm, and thus, the air-blown optical fiber unit production is limited by factors such as equipment, materials, production technology, patent limitation and the like, and domestic manufacturers cannot provide corresponding products at present.

The loose tube is used as a basic unit of the optical cable, is not limited by the patent, has simple structure, quick processing, low cost and convenient use, and is used as the basic unit to produce the central tube type air-blown micro cable, and is most likely to be applied to the specifications of 5/3.5mm microtubes.

The problems encountered in the actual development process at present are: 1) The diameter of the central tube type air-blowing micro-cable structure is relatively large, and the duty ratio (the area of the outer edge of the cross section of the micro-cable/the area of the inner edge of the cross section of the micro-cable) in a micro-pipe with the specification of 5/3.5mm is higher, so that the air-blowing effect is influenced; 2) The center tube type air-blown micro-cable sheath is made of high-density polyethylene HDPE, the friction coefficient of the center tube type air-blown micro-cable sheath is different from 0.12 to 0.35, the friction coefficient is mainly related to the brand and processing technology of sheath materials selected by various manufacturers, and under the condition of high duty ratio, the air-blown micro-cable with the structure is difficult to have a better air-blown effect, so that in order to make up the deficiency of the friction coefficient, the surface of the sheath is provided with a plurality of air-flow channels, the friction coefficient of the product can be objectively reduced, but in the actual air-blown application, the abrasion of the sheath surface material and the adhesion of high-temperature and high-pressure materials are not great, the air-blown effect is difficult to improve, the large breakthrough is difficult to meet the requirements of long-distance air-blown and high-efficiency construction of customers, and the engineering progress can be influenced under the condition of encountering complicated construction route and poor pipeline quality; 3) When the HDPE is used as the sheath material and the HDPE material is used as the same material of the air-blowing micro-pipe, the fluctuation range of the friction coefficient is particularly large, the air-blowing effect is reflected to be that the air-blowing speed is unstable, the air-blowing construction safety is affected, and 4) the environment resistance of the optical cable is relatively poor, and the sheath is retracted and extended due to the fact that the HDPE sheath is contracted and extended due to the change of the environment temperature, and the optical fiber transmission performance is deteriorated due to the retraction and extension of the sheath caused by the high-low temperature change of the cable which is already laid.

Disclosure of Invention

Aiming at the defects or improvement demands of the prior art, the invention provides a preparation method of an ultra-low friction coefficient central tube type air-blown micro cable and a sheath thereof, which can be applied to long-distance air-blown laying in a micro pipe with the thickness of 5/3.5mm, and has the remarkable advantages of extremely low friction coefficient, narrow fluctuation range of the friction coefficient, excellent high and low temperature environment resistance, simple structure, low manufacturing cost and the like.

In order to achieve the above object, according to one aspect of the present invention, there is provided an ultra-low friction coefficient center tube type air-blown micro cable comprising a sheath, characterized in that a mixture from which the optical cable sheath is made mainly comprises polyoxymethylene, molybdenum disulfide, a compatibilizer, an antioxidant, an aldehyde absorbing agent and a light shielding agent;

in the mixture, the mass part of the polyoxymethylene is 85-95 parts, and the mass part of the molybdenum disulfide is 3-13 parts.

Preferably, the friction coefficient of the sheath relative to the 5/3.5 mm-specification air-blowing plastic microtube for communication is lower than 0.1, and the material of the 5/3.5 mm-specification air-blowing plastic microtube for communication is HDPE.

Preferably, the outer diameter of the sheath is 1.6 mm-2.6 mm.

Preferably, the sheath of the air-blown micro cable has a fluctuation range of less than 0.01 in the friction coefficient test process relative to a 5/3.5mm specification air-blown plastic micro tube for communication.

Preferably, the compatilizer is 0.05 to 0.2 part by weight, the antioxidant is 0.05 to 0.2 part by weight, the aldehyde absorber is 0.03 to 0.1 part by weight, and the light shielding agent is 2 to 3 parts by weight.

Preferably, the antioxidant is one or more of a polyphenol hindered phenol antioxidant, a phosphorous acid antioxidant and a hindered amine.

Preferably, the light shielding agent is conductive carbon black or hindered amine

Preferably, the optical fiber bundle in the single loose tube in the sheath of the air-blown micro cable comprises 2-24 optical fibers.

Preferably, aramid yarns are bound on the loose tubes in the sheath to serve as reinforcing tensile elements.

According to another aspect of the invention, there is also provided a method for preparing the sheath of the ultra-low friction coefficient central tube type air-blown micro cable, which is characterized by comprising the following steps:

1) Adding polyoxymethylene and molybdenum disulfide into a mixing kettle of a high-speed mixer, uniformly mixing, then adding a compatilizer, an antioxidant, an aldehyde absorbing agent and a light shielding agent, and uniformly mixing to form a mixture;

in the mixture, the mass part of the polyoxymethylene is 85-95 parts, and the mass part of the molybdenum disulfide is 3-13 parts;

2) Mixing the mixture in a double-screw extruder, and then sequentially extruding, cooling, granulating and drying to obtain a sheath material, wherein the extrusion temperature of the double-screw extruder is 180-190 ℃;

3) The sheath material is extruded by an extruder to form the sheath.

In general, the above technical solutions conceived by the present invention, compared with the prior art, enable the following beneficial effects to be obtained:

1) One of the base materials used in the invention is polyformaldehyde, has hardness, strength and rigidity similar to those of metal, has better wear resistance, can be used for a long time at-40 ℃ to 100 ℃, has good self-lubricity and fatigue resistance under wide temperature and humidity conditions, has a friction coefficient of pure materials larger than that of HDPE, and has extremely low friction coefficient under lubrication conditions (for example, the friction coefficient can reach 0.012 to 0.018 under lubrication conditions); the second base material used is molybdenum disulfide which is in a 2H crystal form and has a special lamellar structure, and all layers are connected with each other by extremely tiny molecular force. The molybdenum disulfide is easy to separate from layers, so that the molybdenum disulfide has good lubricating property, is known as high-grade solid lubricating oil, and forms an interface lubricating film between the surface of the micro cable sheath and the micro pipe under the condition of mixing in a low proportion, so that the friction part between the surface of the sheath and the micro pipe is converted into intermolecular sliding, and the effects of reducing the friction coefficient of the surface of the sheath and improving the abrasion resistance of the sheath are achieved.

2) The invention adopts the materials such as polyformaldehyde, molybdenum disulfide, compatilizer, antioxidant, aldehyde absorbing agent, and the like to prepare the sheath, thereby greatly reducing the friction coefficient of the surface of the central tube type air-blown micro-cable, greatly improving the air-blown distance of the micro-cable product, improving the construction efficiency and reducing the construction cost.

3) Compared with a common 5/3.5-specification air-blowing plastic microtube for communication in the industry, the friction coefficient of the central tube type air-blowing micro cable sheath provided by the invention has the advantages that the fluctuation amplitude is smaller than 0.01 in the test process, almost is a straight line, and is far smaller than the fluctuation amplitude of the friction coefficient of an HDPE sheath material. The air blowing speed is stable and orderly, the condition of negligence and speed is avoided, and the construction safety is ensured.

4) The optical cable of the invention has stable environmental resistance, especially when used in low temperature (-40 deg) environment, the optical fiber attenuation is basically unchanged, and the stability of the optical fiber transmission performance is ensured.

5) The invention can be laid in a communication air-blowing plastic microtube with a distance of 5/3.5mm or smaller in an air-blowing way, thereby meeting the air-blowing effect and the construction efficiency of customers.

Drawings

FIG. 1 is a schematic illustration of an ultra-low coefficient of friction center tube type air-blown micro-cable of the present invention;

FIG. 2 is a graph showing fluctuation of the results of the test on the friction coefficient of the center tube type air-blown micro-cables produced in comparative examples 1, 2 and example 2 in the same 5/3.5mm air-blown micro-tube.

Detailed Description

The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention. In addition, the technical features of the embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.

The invention relates to a center tube type air-blown micro cable with an ultralow friction coefficient, which comprises a sheath 4 and loose tubes 2 coated in the sheath 4, wherein optical fiber bundles 1 are distributed in the loose tubes 2, each optical fiber bundle 1 in each loose tube 2 is provided with 2-24 colored optical fibers 1, and the loose tubes 2 contain fiber paste, so that the optical fibers are in a free state; the sheath 4 is mainly formed by extruding materials such as polyoxymethylene, molybdenum disulfide, compatilizer, antioxidant and aldehyde absorbing agent after being blended, a reinforcing tensile member 3 can be arranged between the sheath 4 and the loose tube 2, and the reinforcing tensile member 3 is preferably aramid yarn.

The sheath 4 is mainly prepared from the following base materials in parts by weight: 85-95 parts of polyformaldehyde, 3-13 parts of molybdenum disulfide, 0.05-0.2 part of compatilizer, 0.05-0.2 part of antioxidant, 0.03-0.1 part of aldehyde absorber and 2-3 parts of light shielding agent.

The friction coefficient of the ultra-low friction coefficient central tube type air-blown micro cable is smaller than 0.1, preferably smaller than 0.05, relative to a 5/3.5mm (outer diameter 5mm, inner diameter 3.5 mm) specification air-blown plastic micro pipe which is used for communication and is common in the industry.

The polyoxymethylene is preferably copolyformaldehyde, which has much better thermal stability than homo-polyoxymethylene.

The molybdenum disulfide is preferably solid powder obtained by chemical purification of natural molybdenum concentrate powder, and has the effects of reducing the friction coefficient of the surface of the sheath 4 and improving the wear resistance of the sheath 4, and particularly the capability is more prominent at high temperature and high pressure, and the wear resistance and the friction coefficient of the sheath 4 are slightly different according to different adding proportions.

The antioxidant is one or more of a polyphenol hindered phenol antioxidant, a phosphorous acid antioxidant and a high molecular weight hindered amine, preferably, the mixture comprises the three components of 0.01 part of the polyphenol hindered phenol antioxidant, 0.03 part of the phosphorous acid antioxidant and 0.04 part of the high molecular weight hindered amine in parts by weight, and the use effect is good.

The light shielding agent is carbon black, preferably nanoscale conductive carbon black, not only can greatly improve the light resistance and weather resistance of the sheath, but also can enable the sheath to have antistatic property, eliminates electrostatic adsorption resistance generated by friction between plastics in the air blowing process, and is beneficial to air blowing construction.

The compatilizer is preferably a mixture of Maleic Anhydride (MAH) and 2, 5-dimethyl-2, 5-bis (tert-butylperoxy) hexane (commonly called as a bis-dipentaerythritol vulcanizing agent) in a mass part ratio of (1-2): (0.5-1), preferably 2:1, ensures that molybdenum disulfide and various additives are well compatible with polyoxymethylene, and can lead the molybdenum disulfide to have a molecular linking effect on an interface with polyoxymethylene, namely a compatibility effect.

The formaldehyde absorber is preferably a formic acid absorber, and mainly suppresses the generation of formaldehyde gas during extrusion. In the production and processing and granulation processes, the influence of oxygen and high temperature causes the chain breakage of hydroxyl at the end of the polyformaldehyde to be divided into Jie Cheng formic acid, the formic acid can in turn promote the continuous decomposition of the polyformaldehyde, so that vicious circle is caused, the formic acid absorbent can absorb the formic acid of the polyformaldehyde, and simultaneously absorb the formic acid generated by the polyformaldehyde product in production, and the acidolysis reaction of the formic acid is interrupted, thereby achieving the purpose of avoiding the decomposition of the polyformaldehyde, avoiding the corrosion to the metal surface of processing equipment and having important protection effect on the equipment.

One of the base materials of the sheath 4 with low friction coefficient is polyoxymethylene, which is widely used for manufacturing various sliding and rotating mechanical parts, and almost no report is made for optical cable sheath materials, but the sheath has hardness, strength and rigidity similar to those of metal, good wear resistance, long-term use at-40 ℃ to 100 ℃, good self-lubricity and good fatigue resistance under wide temperature and humidity conditions, and the friction coefficient of pure materials is larger than that of HDPE, but has extremely low friction coefficient under the lubrication condition (for example, the friction coefficient under the lubrication condition can reach 0.012 to 0.018); the second base material is molybdenum disulfide which is generally used as a solid lubricant, the molybdenum disulfide is in a 2H crystal form and has a special lamellar structure, and all layers are connected with each other by extremely tiny molecular force. The molybdenum disulfide is easy to separate from layers, so that the molybdenum disulfide has good lubricating property, is known as high-grade solid lubricating oil, and forms an interface lubricating film between the surface of the micro cable sheath and the micro pipe under the condition of mixing in a low proportion, so that the friction part between the surface of the sheath and the micro pipe is converted into intermolecular sliding, and the effects of reducing the friction coefficient of the surface of the sheath and improving the wear resistance of the sheath are achieved

The polyformaldehyde and the molybdenum disulfide are used as the base materials and are supplemented with the compatilizer, the antioxidant, the aldehyde absorbing agent and the light shielding agent, so that the heat resistance, the light resistance, the aging resistance, the low temperature shrinkage resistance and other related properties of the sheath 4 can be obviously improved, the electrostatic adsorption in the air blowing process can be eliminated, the comprehensive performance of the optical cable product is excellent, the air blowing performance and the temperature environment change resistance of the product are greatly superior to those of the optical cable with the traditional HDPE sheath, and the development and application requirements of the air blowing product in a 5/3.5mm microtube can be well met.

The low-friction-coefficient central tube type air-blown micro cable provided by the invention abandons the traditional sheath 4 with limited and unstable minimum friction coefficient and adopts HDPE material, and develops the sheath 4 with low friction coefficient, which is suitable for extrusion processing of optical cables, and has the advantages of extremely low friction coefficient, high strength, high hardness and strong wear resistance of the sheath 4. When the air-blown micro cable is air-blown in the plastic pipeline, the good conductivity can also avoid the influence of electrostatic adsorption on the air-blowing performance.

The preparation process of the sheath 4 of the low friction coefficient central tube type air-blown micro cable suitable for optical cable extrusion processing comprises the following steps:

1) Adding polyoxymethylene and molybdenum disulfide into a mixing kettle of a high-speed mixer, uniformly mixing, wherein the polyoxymethylene is added from a main material port, the molybdenum disulfide is added from a lateral port, uniformly mixing for a set time of low-speed mixing, and then uniformly mixing for a set time of high-speed mixing to form a mixture by adding a compatilizer, an antioxidant, an aldehyde absorbing agent, a light shielding agent;

3) The sheath material is extruded by an extruder to form the sheath.

Wherein, the mass part ratio and other technical parameters of each raw material added in the step 1) are shown in examples 1-9 in the following table 1.

The materials and preparation methods of the sheaths of comparative examples 1, 2 in table 1 use conventional techniques.

The preparation process of the sheaths of comparative examples 3 and 4 in table 1 is substantially the same as that of examples 1 to 9 of the present invention, except that the proportions of the respective raw materials in parts by mass in step 1) of comparative examples 3 and 4 are different.

Table 1 comparison of raw material ratios, friction coefficients and air blowing properties of sample examples and comparative examples

It can be seen from the 4#/7#/10#/12# 13# samples in table 1 that the friction coefficients of the two types of jackets 4 of the examples and the comparative examples are substantially different by one order of magnitude, and the surface friction coefficient can be suitably improved by adding molybdenum disulfide in different proportions, and the friction coefficient is not continuously decreased but is increased again after the addition amount is increased to a certain proportion.

It can be seen from the examples of the 3#/4#/5# samples in table 1 that the amount of auxiliary added within the given range has a slight effect on the coefficient of friction.

The center tube type air-blown micro-cables produced in comparative example 1, comparative example 2 (sample # 1/sample # 2) and example 2 (sample # 4) were subjected to friction coefficient test in the same 5/3.5mm air-blown micro-tube, and the results are shown in fig. 2.

As can be seen from fig. 2, the air-blown micro-cable with HDPE sheath adopted by the samples # 1 and # 2 has very large fluctuation range, the fluctuation amplitude almost reaches more than 30%, and the friction coefficient of the air-blown micro-cable produced by adopting the sheath material of the invention is basically a smooth line. As can be seen from the comparative examples of the 1# and 13# samples in Table 1, even in the case where the friction coefficients were the same (both 0.14), the effect of the air-blown distance using the sheath of the present invention was significantly better, and thus it was very advantageous for air-blown construction.

It will be readily appreciated by those skilled in the art that the foregoing description is merely a preferred embodiment of the invention and is not intended to limit the invention, but any modifications, equivalents, improvements or alternatives falling within the spirit and principles of the invention are intended to be included within the scope of the invention.

Claims

1. The central tube type air-blown micro cable with the ultralow friction coefficient is used for increasing the air-blown distance and reducing the fluctuation range of the friction coefficient and comprises a sheath, and is characterized in that a mixture for preparing the sheath comprises polyoxymethylene, molybdenum disulfide, a compatilizer, an antioxidant, an aldehyde absorbing agent and a light shielding agent;

in the mixture, the weight part of the polyoxymethylene is 85-95 parts, the weight part of the molybdenum disulfide is 3-13 parts, the weight part of the compatilizer is 0.05-0.2 part, the weight part of the antioxidant is 0.05-0.2 part, the weight part of the aldehyde absorbing agent is 0.03-0.1 part, and the weight part of the light shielding agent is 2-3 parts;

the compatilizer is a mixture of maleic anhydride and a bis-dipentaerythritol vulcanizing agent, and the mass part ratio of the maleic anhydride to the bis-dipentaerythritol vulcanizing agent is (1-2): (0.5-1).

2. The ultra-low coefficient of friction center tube type air-blown micro cable according to claim 1, wherein the friction coefficient of the sheath relative to the 5/3.5mm specification air-blown plastic micro tube for communication is lower than 0.1, and the material of the 5/3.5mm specification air-blown plastic micro tube for communication is HDPE.

3. The ultra-low coefficient of friction center tube type air-blown micro cable of claim 2, wherein the outer diameter of the sheath is 1.6 mm-2.6 mm.

4. The ultra-low coefficient of friction center tube type air-blown micro cable according to claim 1, wherein the fluctuation amplitude of the sheath of the air-blown micro cable in the friction coefficient test process is less than 0.01 relative to a 5/3.5mm specification air-blown plastic micro tube for communication.

5. The ultra-low coefficient of friction center tube type air-blown micro cable according to claim 1, wherein the antioxidant is one or more of a polyphenol hindered phenol antioxidant, a phosphorous acid antioxidant and a hindered amine.

6. The ultra-low coefficient of friction center tube type air-blown micro cable according to claim 1, wherein the light shielding agent is conductive carbon black or hindered amine.

7. The ultra-low coefficient of friction center tube type air-blown micro cable according to claim 1, wherein the optical fiber bundles in a single loose tube in the sheath of the air-blown micro cable comprise 2-24 optical fibers.

8. The ultra-low friction coefficient central tube type air-blown micro cable according to claim 1, wherein aramid yarn is bound on the loose tube in the sheath to be used as a reinforcing tensile element.

9. The method for preparing the sheath of the ultralow friction coefficient central tube type air-blown micro cable as claimed in any one of claims 1 to 8, which is characterized by comprising the following steps:

in the mixture, the mass part of polyoxymethylene is 85-95 parts, and the mass part of molybdenum disulfide is 3-13 parts;

3) The sheath material is extruded by an extruder to form the sheath.