Key words: optical cable material, chrome-plated steel-plastic composite tape, smooth aluminum-plastic composite tape, chrome-plated steel tape, plastic film.
Steel-plastic composite tape and aluminum-plastic composite tape are mainly used for the outer sheath of communication optical cable and communication cable, and they are bonded with the sheath material to form a comprehensive sheath layer, which plays a role in moisture prevention and protects the cable core from moisture erosion. At the same time, the steel-plastic composite tape and the aluminum-plastic composite tape have armor function on the cable core, resist external force, provide mechanical protection for laying communication optical cables and communication cables in various applications, and ensure the stability and reliability of applications.
Optical communication based on optical fiber has the characteristics of extremely wide transmission frequency band and large communication capacity. In modern communication, optical fiber communication is widely used to transmit ultra-large capacity signals. Therefore, the reliability and stability of the carrier are very high, otherwise it may lead to communication obstacles in a large area. In the long-distance optical cable communication system, the transmission characteristics of optical cable should be stable for a long time. Making optical fiber into optical cable is to select raw materials with excellent performance, protect optical fiber and ensure the reliability and stability of optical fiber transmission during its service life. Steel-plastic composite tape and aluminum-plastic composite tape in optical cable play a very important role in protecting optical fiber.
In recent years, the competition in the optical cable market is fierce, the price is falling, and the cost pressure of optical cable manufacturing is high, which leads to the cost pressure of producing composite tape, and some enterprises even have a survival crisis. Under the severe situation, these manufacturers use inferior materials to make inferior products, which makes the quality of composite tapes on the market mixed. This kind of manufacturers only pay attention to their own economic benefits and do not talk about social responsibility, which brings great hidden dangers to optical fiber and cable communication.
Through the analysis of steel-plastic and aluminum-plastic composite tape, this paper will explain the influence of the material and production technology of composite tape on the technological characteristics and quality of optical cable, and how to distinguish the advantages and disadvantages of composite tape by simple methods.
First, the status quo of steel-plastic and aluminum-plastic composite tape
We and Hua Fei Institute of Beihou University have tested more than a dozen domestic representative composite tape products collected from various optical cable production sites, and the results are as follows:
1, mechanical properties:
Tensile strength, RP0.2 (non-proportional elongation strength) and elongation at break are three indexes, which depend on the metal base tape of the composite tape and reflect the performance of the base tape.
The maximum tensile strength of steel-plastic composite tape can reach 376.07Mpa, the maximum non-proportional tensile strength of RP0.2 can reach 35 1. 12Mpa, and the maximum elongation at break can reach 29.82%. The lowest tensile strength is only 343. 15 Mpa, the lowest RP0.2 (non-proportional tensile strength) is 262.47 Mpa, and the lowest elongation at break is only 17.52%. Even if some manufacturers take six samples from the same composite band, the measured data are quite different, σ reaches 20.975, which shows that the baseband performance they use is very unstable and discrete. However, the product performance of some manufacturers is relatively stable, and the dispersion is very small, σ is only 1.2 12.
The maximum tensile strength of aluminum-plastic composite tape can reach 97.56Mpa, the maximum non-proportional tensile strength of RP0.2 can reach 70.84Mpa, and the maximum elongation at break can reach 32.74%. The lowest tensile strength is only 77.04 Mpa, the lowest RP0.2 (non-proportional tensile strength) is 48. 16 Mpa, and the lowest elongation at break is only 15. 10%. Some manufacturers even extract six patterns from the same composite tape, but the tested data are quite different. However, some manufacturers have good performance indicators, and the deviation σ is only 1.547.
From the analysis of test data, the baseband used by different manufacturers is still very different. Imported chromium-plated steel strip has good mechanical properties and small dispersion. However, the properties of domestic strip steel are unstable and discrete. It should be said that the performance gap of domestic steel belts in terms of materials is not small. From the perspective of aluminum ribbon, the quality difference of cable aluminum baseband produced by different aluminum factories in China is also very obvious.
2. Adhesion performance:
Peeling strength-an index to measure the adhesion between metal base tape and film. From the analysis of the test results of steel-plastic composite belt, four product samples are unqualified, of which two product samples A and B are unqualified, and two product samples A and B are unqualified. Only a few manufacturers have good products. The peeling strength of surface A and surface B is very large, and the difference is very small. The standard deviation is only 0. 1 14. The steel base band it uses is imported chrome-plated steel belt.
According to the test data of water-resistant peeling strength of steel-plastic composite belt, as long as one product sample from two factories is qualified, the others are unqualified, which reflects that most products have poor water-resistant environmental performance.
Heat sealing strength-an index to measure the adhesive force between the A side and the B side of the composite tape, which directly affects the quality of the longitudinal lap joint of the composite tape as a moisture barrier. According to the test results, only 1 7.21n/cm of steel-plastic composite tape from one manufacturer is unqualified, and the samples from most manufacturers are between 17.88- 19.77N/cm, and some manufacturers reach 37.72 N/cm. Only one manufacturer's 16.92 N/cm is unqualified, and others are between 19.49-24.65N/cm.
Shear strength-a measure of the shear resistance of composite tape after heat sealing, which directly reflects the external force at the "seam sealing" of steel-plastic and aluminum-plastic composite tape after making optical cable. From the analysis of test data, although all products meet the requirements of no shear failure in the heat seal area, the shear force values of products from different manufacturers are still quite different. The shear force value of the best manufacturer's heat sealing zone of steel-plastic composite belt reaches 578.87n/cm；; . The worst manufacturer only reached 435. 16N/cm. The shear force of the best manufacturer of aluminum-plastic composite tape reaches182.5438+04n/cm; The worst manufacturer only reached 1 19.5438+0N/cm.
The bonding performance of the composite tape is mainly related to the material properties of the film, the composite technology level of the manufacturer and the quality of the metal base tape. From the analysis of test data, the products with excellent performance adopt imported chrome-plated steel baseband and high-quality cable aluminum baseband, and the selected polymer and its process level are also excellent.
3. Compatibility:
Metal-plastic composite tape is in long-term contact with the ointment in optical cable, so its compatibility with the ointment needs to be considered. The filling-resistant composite test is to observe whether there will be bubbles or delamination between the metal base tape and the polymer film in the ointment, that is, to evaluate the compatibility between the composite adhesive tape and the optical cable filling ointment. The test method is to immerse each group of 6 samples 50mm×50mm into a beaker filled with optical cable filling ointment, and then put the beaker into an oven with a constant temperature of 68 1℃ 168h for observation. Test results: All passed.
In order to distinguish the advantages and disadvantages, we extended the time to 192h, 2 16h and 240h for observation. After 240h accelerated aging test, overall, the qualified rate of steel-plastic composite tape is 6 1%, the qualified rate of aluminum-plastic composite tape is 58%, and the plastic layer of aluminum-plastic composite tape falls off, accounting for 8%. At the same time, we also see that the samples of steel-plastic composite tapes from three manufacturers and aluminum-plastic composite tapes from three manufacturers have been in good condition during the whole accelerated test, without bubbles and delamination.
The test results show that the compatibility of composite tape and ointment is stable. After accelerated aging test, it can be seen that the compatibility between steel-plastic composite tape and ointment is better than that between aluminum-plastic composite tape and ointment. There are still obvious differences between the products of different manufacturers.
4. Corrosion resistance:
Check whether the metal-plastic composite tape will delaminate between the polymer film and the metal baseband in acidic or alkaline environment and whether it will cause corrosion to the metal baseband. The test was carried out according to YD/T723. Six samples of steel-plastic composite strip in each group were soaked in 0. 1mol/LHCL solution for 480h, and the samples of non-chromium plated steel strip products from two manufacturers were unqualified. Increasing the solution concentration and soaking in 0.2mol/LHCL solution for 240h, it was observed that the sample films of non-chromium plated steel strip products from two manufacturers fell off and were oxidized, and other manufacturers were qualified; When the solution concentration was increased and soaked in 0.3mol/LHCL solution for 192h, it was observed that the products of four manufacturers were all qualified after a long-term harsh environmental test, and they could also reach the corrosion resistance grade of 8 ~ 10. Six samples of aluminum-plastic composite tape in each group were soaked in 0. 1mol/L NAOH solution for 480h, and two samples from manufacturers were unqualified, and one of them was almost completely corroded. Increase the solution concentration, soak in 0.2mol/L NAOH solution for 240h, and only the product samples from one manufacturer pass; When the concentration of the solution is increased and soaked in 0.3mol/L NAOH solution for 65438 0.92 h, all samples can't pass.
The test results show that the corrosion resistance of products from different manufacturers is very different. In the steel-plastic composite belt, the corrosion resistance of chromium-plated steel belt is good, but the corrosion resistance of chromium-free steel belt is much worse.
5. Dielectric characteristics:
YD/T723 Metal-plastic Composite Tape for Communication Cables and Optical Cables requires that the dielectric strength of double-sided steel-plastic composite tape and aluminum-plastic composite tape is 2kVd.c, 1min, and all samples have passed the test. So we raised the voltage to 5kvd.c, 1min, and all the samples still passed the test, which showed that the dielectric strength of double-sided steel-plastic composite tape and aluminum-plastic composite tape completely met the requirements, and the safety factor was high.
Secondly, the influence of the materials used in the composite tape on the technology and quality of the optical cable.
At present, the main materials of metal-plastic composite tape for optical cable are chrome-plated steel tape, aluminum tape for cable, ethylene acrylic polymer and so on. The properties of metal-plastic composite tape are closely related to the properties of raw materials used. According to the test results, the mechanical properties and corrosion resistance of composite tape are determined by the quality of metal base tape, while the quality of metal base tape and * * * polymer directly affects the quality of adhesive properties of composite tape. Users who have strict requirements on the quality of optical cables need to control the performance of raw materials to ensure the quality of optical cables.
The base band of steel-plastic composite belt should be chrome-plated steel belt (TFS for short). The characteristics of chromium-plated steel strip are: because the surface of steel strip is coated with a layer of chromium, the chemical properties of chromium are very stable, and it will not rust when placed in air or immersed in water at room temperature, and its corrosion resistance is very good. Chromium is easily oxidized to form a thin passivation layer in the atmosphere, so it has good environmental resistance and is stable in general acidic environment and humid atmosphere. Chromium-plated steel strip has strong adhesion, and some data show that its adhesion to organic coating is 3 ~ 6 times stronger than that of tin-plated steel strip, so chromium-plated steel-plastic composite strip has good adhesion. Chromium-plated steel strip also has good high temperature resistance, and the melting point of chromium is as high as 1900℃.
In order to reduce the cost, some manufacturers use tinned steel strip as the baseband to produce steel-plastic composite belt. Tinned steel strip (ETS) has good corrosion resistance in dry and clean atmosphere. However, pinholes and bubbles on the surface of tin coating are inevitable, so it is easy to corrode in humid atmosphere under the condition of surface condensation or immersion, especially in the environment with acid or trace salt, and the corrosion rate is quite fast. Tin coating has poor heat resistance, and its melting point is only 232℃. Therefore, the peeling strength of tin-plated steel-plastic composite tape is uncertain due to the high temperature when the sheath is extruded.
Other manufacturers use uncoated steel strip, also known as BlackPlate or cmq (canned high-quality black steel plate), as the base band to produce steel-plastic composite strip. The outstanding disadvantage of this kind of steel strip is that its corrosion resistance is particularly poor, and it is easy to corrode in humid atmosphere and under the conditions of dew condensation or immersion on the surface. In acidic or reducing environment, the corrosion rate is very fast, which leads to perforation, air leakage and moisture entry of steel strip, resulting in communication obstacles. The adhesion between the steel base tape and the film of this composite tape is poor, the peeling strength is very low, and cracks are easy to appear in the overlapping part of the longitudinal packaging, so that moisture can enter. After the optical cable is made, the steel base band and the sheath are easy to separate, so it is impossible to form a comprehensive bonded sheath, and the moisture-proof performance is very poor.
Steel-plastic composite tape made of tinned steel tape and black iron sheet often fails to pass the corrosion resistance test specified in the standard of Metal-plastic Composite Tape for Optical Cable because of its poor corrosion resistance and poor adhesion to film.
It should be pointed out that hydrogen loss is a dangerous factor leading to the increase of optical fiber attenuation. We know that the reaction between active metals and acids, and the electrochemical reaction of two metals with potential difference in acidic environment, even in weak acidic environment, will lead to hydrogen evolution. Both tin-plated steel strip and black iron sheet have internal conditions for hydrogen evolution. If the acid value of the ointment is too large, if the sheath is damaged and the use environment has certain conditions, micro-batteries may be formed during the corrosion process, which greatly increases the risk of hydrogen production and causes great damage to optical fibers.
How to distinguish whether the base band of steel-plastic composite belt is chrome-plated steel belt, tin-plated steel belt or black iron sheet? Strictly speaking, it can be identified by spectrometer, coating thickness analyzer, scanning electron microscope and other methods, but optical cable manufacturers and communication operators usually do not have these instruments. It is advisable to recommend a simple and effective identification method explored in practice: cut a section of steel-plastic composite tape (about 200mm in length) (or cut a section of optical cable composite sheath, peel off the sheath material, and then unfold the exposed steel-plastic composite tape); Burn the plastic film on the steel-plastic composite belt with alcohol lamp or lighter, and then observe: all chrome-plated steel-plastic composite belts are white with a little yellowish after burning; Tinned steel-plastic composite tape or uncoated steel-plastic composite tape is black or slightly dark blue after firing.
The quality difference of steel baseband with the same material and different brands is also great. At present, domestic enterprises producing chrome-plated steel baseband for optical cables are small enterprises with outdated equipment, backward technology and unstable raw material composition. Compared with foreign products, the quality gap of domestic materials is still large, the chemical composition fluctuates greatly, and the mechanical properties are unstable and discrete, which can be seen in the first section of this paper. The dimensional accuracy of finished products is not high, and the thickness tolerance of foreign products is controlled within 5 microns, while that of domestic products is often as high as 8 μ m, which makes the manufacturing cost of optical cables uncontrollable. There are many surface defects, inclusions, pinholes, etc. These defects are often hidden and difficult to find, and the tape is easy to break in the process of producing optical cables. Obviously, it has caused a high rejection rate for users.
The quality of aluminum strip also plays a decisive role in the mechanical properties and corrosion resistance of aluminum-plastic composite strip, and the product quality differences of different aluminum factories in China are also very obvious. Selecting high-quality cable aluminum baseband is the basis of producing high-quality aluminum-plastic composite tape.
The requirement for * * * polymer materials is to have good adhesion with metal base tape and sheath materials at the same time. At present, the ideal material is ethylene acrylic acid * * * polymer (EAA) or methyl ethylene acrylic acid * * * polymer (EMAA), which is a polar material. It can be well combined with metal and has good compatibility with sheath material. Due to the low melting point of EAA and good self-adhesion of longitudinal package, it is usually unnecessary to use hot air gun.
Third, the influence of composite tape technology on the technology and quality of optical cable
1, the influence of composite technology on the production process of optical cable
Metal-plastic composite tape is composed of metal layer and polymer film compounded on one or both sides. The main technical index to measure composite technology is the adhesive property of composite tape. Adhesion usually refers to the following three aspects: one is the adhesion between metal base tape and film, and the other is the adhesion between composite tape and sheath material. To obtain excellent bonding performance, first, it depends on material selection, and second, it depends on technology. As far as technology is concerned, steel-plastic composite tapes and aluminum-plastic composite tapes for optical cables are generally produced by tape casting and thermal bonding. In recent years, with the continuous progress of metal-plastic composite tape technology, thermal adhesive films have developed from pe films and EAA(EMAA) single-layer films to EAA/PE/EAA and EAA/PE/PE structural films today. Under normal circumstances, composite tape production enterprises can produce qualified products and meet the requirements of producing optical cables through raw material control and strict process control. EAA/PE/EAA structure film usually does not need to use hot air gun because of its low melting point and good self-adhesive performance of longitudinal lap joint. However, due to the high melting point of EAA/PE/PE structural film, it is usually necessary to use hot air gun when winding vertically.
Due to the uneven management level, process level and equipment technology level of composite tape production enterprises, the quality of the products produced is uneven, and inferior products will bring great trouble to the production of optical cables.
2. The influence of mechanical deformation on the production process of optical cable
When metal-plastic composite tape is used in optical cable production, it must be cut into strips according to the required width, and the cutting quality directly affects the optical cable production. Steel-plastic composite tape and aluminum-plastic composite tape should be cut without knife marks and ruffles, and the end faces should be flat. The tape is flat when it is released. In this way, it is easy to form in the production process of optical cable, the lap joint is not easy to tilt, the adhesion is good, and the comprehensive protective layer has good moisture-proof effect. The opposite is not the case.
3. The influence of dynamic friction coefficient on the production process of optical cable.
We use different aluminum-plastic composite tapes to simulate the production environment on the longitudinal wrapping table. The resistance of the smooth aluminum-plastic composite belt manufactured by Xi Anqinbang's patented technology when passing through the longitudinal wrapping die is obviously different from that of the ordinary aluminum-plastic composite belt. The resistance of the former is 26.6% ~ 55.5% lower than that of the latter. We also used GB 10006 method to test the friction coefficient (μd) of aluminum-plastic composite transmission. Under the atmospheric pressure of 9.8 1N, the former μd is between 0.3 and 0.4, and the latter is as high as 0.6. The friction coefficient of metal-plastic composite tape has obvious influence on the production process of optical cable, especially aluminum-plastic composite tape, because its mechanical strength is much lower than that of steel-plastic composite tape, its tensile strength and deformation resistance are much smaller. In practical work, in addition to process adjustment problems, failures or other human factors, excessive dynamic friction coefficient is often the main reason for the fracture of aluminum-plastic composite tape in optical cable production. The optical cable is made of aluminum-plastic composite tape with low surface friction coefficient, which has small deformation and is easy to form. The advantages it brings are: firstly, it is not easy to break the belt, which reduces the trouble of breaking the belt; Secondly, under the condition of good process coordination, the speed of production line can be obviously improved, that is, the work efficiency can be improved; The biggest advantage is to ensure the quality of optical cable. Because the mechanical deformation of aluminum strip is small, the mechanical properties of aluminum-plastic composite sheath are good, which is beneficial to ensure the service life of optical cable. Shanghai Netcom Optical Cable Materials Co., Ltd. and Xi Anqinbang Telecom Materials Co., Ltd. take dynamic friction coefficient as the evaluation index of products.
How to distinguish smooth aluminum-plastic composite tape from ordinary aluminum-plastic composite tape? Here's a simple method: bake the local area of aluminum-plastic composite tape with alcohol lamp or lighter for a few seconds, and then observe after the aluminum-plastic composite tape is completely cooled: you can see that there is an obvious dividing line between the baked aluminum-plastic composite tape and the unbaked aluminum-plastic composite tape. When you touch it gently along the longitudinal direction of the aluminum-plastic composite tape with your hand, you can obviously feel that the friction coefficient has a sudden watershed, from very smooth to very astringent, which is the smooth aluminum-plastic composite tape. However, no matter how the ordinary products are baked, there is neither a dividing line of fire baking nor a watershed of sudden change of friction coefficient.
4. The metal-plastic composite tape with a long single disc can reduce the splicing of optical cables, reduce the splicing risk and improve the production efficiency; However, a single metal-plastic composite tape has no joint, which can reduce the risk of cable production interruption. Shanghai Netcom Optical Cable Material Co., Ltd. has been able to produce products with a single disc length of 5000m and no joints for users to use.
Four. conclusion
1, the quality of metal-plastic composite tape is mixed, and the quality of some manufacturers' products is equivalent to that of well-known foreign brands, and they compete on the same stage in the international market; Some manufacturers are keen on "tapping the potential", stealing the column and ignoring social responsibility. Responsible optical cable manufacturers and quality-seeking optical cable users should effectively control the quality of raw materials.
2. Compared with imported chromium-plated steel strip, the quality gap of domestic materials is still large, which is mainly manifested in the fluctuation of chemical composition, unstable mechanical properties, low dimensional accuracy of finished products, surface defects, inclusions and many pinholes.
3. The mechanical properties, corrosion resistance, adhesion and other performance indexes of the composite tape produced by chromium-plated steel strip are good, which can ensure the long-term stable and reliable operation of optical cable. However, the composite tapes made of other steel belts have relatively poor indexes, especially corrosion resistance, adhesion performance and hydrogen evolution during corrosion, which is very risky to ensure the long-term stable use of optical cables.
4. Before the smooth aluminum-plastic composite tape enters the die of the optical cable sheath extruder, the tape surface is very smooth and the friction coefficient is very small, which is convenient for processing and molding. Therefore, when passing through the preforming die, the forming die and the sizing die of the longitudinal wrapping table, the resistance is small and the deformation is small. Because of the small deformation, it is not easy to break the belt, which reduces the trouble of breaking the belt; Under the condition of good process coordination, the speed of production line can be obviously improved, that is, the work efficiency can be improved; Due to small deformation, the mechanical properties of aluminum-plastic composite sheath are good, which is beneficial to ensure the service life of optical cable. At the same time, it also solves the problem of online use of thin aluminum strip. Once the smooth aluminum-plastic composite tape is processed into optical cable, it will be firmly combined with the sheath material to effectively form a moisture-proof layer.
5. Under the vicious competition of the current price war in the cable industry, in order to reduce the cost, the outer diameter of the optical cable is getting smaller and smaller, and the thin cable core is required to wrap the 0. 15mm composite tape longitudinally, which is really a bit reluctant. Because the diameter of the cable core is small and the composite tape is thick, the lap joint is easy to tilt or bounce off, but it is not easy to bond firmly and the quality is difficult to control. Therefore, it is suggested that the nominal thickness of composite tape specified in the current standard be revised according to the actual situation. For example, according to the different diameters of optical cables, the composite tape can be used in three sections: for optical cables with larger core diameter, the composite tape with a thickness of 0.20mm can be used (because the cable core is thicker, it will be safer and more reliable to choose the composite tape with higher mechanical properties); If the diameter of the cable core is small, use a composite tape with a thickness of 0. 12mm (if you use a composite tape with a thickness of 0. 12mm, it will be easy to form and tightly lap when winding longitudinally, which will not only ensure the quality of the cable, but also save materials and reduce costs. Why not have the best of both worlds? Judging from the moisture-proof effect, the comprehensive protective layer composed of 0. 12mm thick composite tape and sheath material can completely meet the moisture-proof requirements); When the diameter of cable core is between the above two, use 0. 15mm thick composite tape.
product description
Steel-plastic composite tape is mainly used for shielding and armor in optical cables;
1, EGE steel-plastic composite tape is made by coating ethylene-methacrylic acid * * * polymer (EMAA) resin on both sides of chrome-plated steel base tape and tin-plated steel base tape A and B to achieve a certain adhesion, and the color is bright green;
2.EG steel-plastic composite tape is made by coating the A surface of chrome-plated steel base tape and tin-plated steel base tape with ethylene-methacrylic acid * * * polymer (EMAA) resin to achieve certain adhesion, and the color is bright green;
3. The process is thermal bonding;
4. Tempering degree is t1-t2.5;
5. Specifications and performance indicators of aluminum/steel-plastic composite tape:
Project unit aluminum-plastic indicator steel-plastic indicator
Appearance-straight, smooth, uniform, free from impurities, wrinkles and spots; Straight, smooth and uniform, without impurities, wrinkles and spots.
Standard length M2050-31001000-3500
Width mm 20-500 14-405
Baseband thickness mm 0.200 0.02 0.200 0.02
0. 150 0.0 15 0. 150 0.0 15
Film mm 0.058 0.0130.058 0.05438+03
Compound area mm 0.32 0.042 0.32 0.0 15.
0.27 0.042 0.26 0.0 15
Tensile strength MPa ≥ 54 300 ~ 420
Elongation at break% ≥ 15 ≥ 15
Peel strength N/cm ≥6. 13 ≥6. 13.
The peel strength of heat sealing is N/cm ≥ 17.5 ≥ 17.5.
Shear strength of heat seal-there is no shear failure between plastic layers.
Water resistance, peel strength (68 1℃,168h) n/cm ≥ 6.13 ≥ 6.13.
Oil paste resistance (6865438 0℃, 65438 068 h)-no delamination.
Dielectric strength (24 kV, 1 min)-No breakdown.
The corrosion resistance (0. 1mol/L, NaOH, HCL, 480h) is above grade 7.
Note: 1, the model of steel-plastic composite belt is EGE, and the color is green, while the model of aluminum-plastic composite belt is ELE, and the color is natural;
2. The tube core is steel core or plastic core, φ75, φ150;
3, wooden pallet packaging, steel belt fastening packaging, plastic film moisture-proof.
Steel-plastic composite tape 1. Raw materials: product quality is the life of an enterprise. In order to ensure the reliability of quality, all metal substrates are purchased from well-known foreign enterprises, steel foil is from Nippon Steel Co., Ltd., and plastic is a reliable series of products from DuPont Company of the United States. 2. Main performance of the product A. The surface of the steel-plastic composite belt should be flat, smooth and uniform, without mechanical damage defects such as impurities, wrinkles and spots; The longest is 5000M, the widest is 8 10MM, and the narrowest is 12MM. B the cut steel-plastic composite belt shall be flat, with the unevenness of the side edge not more than 2mm, and the end face shall be free from mechanical damage such as curling, notch and burr. There is no obvious wave manifold (commonly known as lotus leaf) at the edge when pulling. 3. Product advantages: A. Excellent mechanical properties Due to the good adhesion between the composite tape and the plastic sheath, the shielding layer and the outer sheath form a whole, which combines the strength of the metal assembly with the ductility and fatigue resistance of the plastic sheath, and improves the mechanical properties of the cable. B. Reliable moisture-proof steel-plastic composite tape has a good barrier effect on the invasion of moisture, thus protecting the cable core. C. extremely high corrosion resistance because the metal pipe shielding tape is coated with plastic layers on both sides, a chemical corrosion-resistant isolation layer is set between the metal component layer and corrosive water and gas. 4. Storage and transportation: a. Transportation: During transportation, the products should be protected from sun and rain, kept clean, dry and pollution-free, and the packaging should be kept intact. B storage: store the product in a clean and dry warehouse far away from fire and heat sources, and avoid direct sunlight. The temperature in the warehouse should not exceed 50℃.