Super-hydrophobic PPR pipe

Abstract

The application relates to a pipeline for water medium, and discloses a super-hydrophobic PPR pipe material which comprises one or more pipe layers, and the innermost pipe layer is prepared from raw materials in the following mass fractions: PPR 90.78-96.5 parts, nano titanium dioxide 2.5-7 parts, and hydrophobic material 3-5 parts; the hydrophobic material is prepared by compounding and mixing silicon material, carbon fluoride and polypropylene in a mass ratio of (1-1.2):(0.8-1.1):1, the silicon material is one of nano silicon dioxide and silicone rubber, the hydrophobic material of the application is added into the pipe material or the innermost layer of the pipe material, under the condition that the pipe material has no toxic and harmful influence on the water medium, the water medium is subjected to small friction in the pipeline, the water flow speed and pressure loss are small, the water flow is stable, and the noise is low.

Description

TECHNICAL FIELD

[0001] The present application relates to a pipeline for water medium, in particular to a super-hydrophobic PPR pipe. BACKGROUND

[0002] The PPR pipe is made of random copolymerized polypropylene, has high plasticity, and is widely used for indoor water pipeline of house building.

[0003] At present, when the pipeline is arranged in a house, the actual pipeline length is much longer than the distance between the water inlet and the water outlet. When the water flows in the pipeline, the water flow pressure and flow rate decrease with the increase of the pipeline length due to the wall sticking effect. Moreover, the pressure of the water flow with reduced flow rate further changes after the water flow passes through the pipeline corner, the water flow is not full, and noise is generated in the gravity flow state.

[0004] In order to provide better home experience, the present applicant has researched a PPR pipe with fast water flow rate and stable flow to reduce noise. SUMMARY

[0005] In order to reduce the water flow fluctuation and noise in the pipeline, a super-hydrophobic PPR pipe is provided.

[0006] The above application purpose of the present application is realized by the following technical scheme:

[0007] A super-hydrophobic PPR pipe comprises one or more pipe layers, and the innermost pipe layer is prepared from the following raw materials in mass fraction:

[0008] PPR 90.78-96.5 parts,

[0009] Nano-titanium dioxide 2.5-7 parts,

[0010] Hydrophobic material 3-5 parts;

[0011] The hydrophobic material comprises silicon material, carbon fluoride, and polypropylene, which are compounded and mixed at a mass ratio of (1-1.2):(0.8-1.1):1, and the silicon material is one of nano-silicon dioxide and silicone rubber.

[0012] By adopting the above technical scheme, the hydrophobic material of the present application is added in the pipe or the innermost layer of the pipe, which ensures that the pipe has no toxic and harmful effect on the water medium, the water medium has small friction in the pipeline, the water flow rate and pressure loss are small, the water flow is stable, and the noise is low.

[0013] Optionally, the nano-titanium dioxide is configured as a color master batch with auxiliary materials, and the auxiliary materials of the color master batch are PPR 0.78-2 parts, oleic acid amide 0.05-0.3 parts, and PE wax 0.5-1.5 parts.

[0014] By adopting the above technical scheme, the nano titanium dioxide is prepared into color master batch and then added, so that the nano titanium dioxide is mixed more uniformly with the organic phase mainly composed of PPR in the pipe material.

[0015] Firstly, the color is more uniform.

[0016] Secondly, the friction coefficient of the pipe wall is reduced, which is beneficial to reduce the friction of the water medium by the pipeline, reduce the water pressure loss and reduce the water flow noise.

[0017] Optionally, the innermost pipe layer raw material further comprises 3.1-4.6 parts of antibacterial material, the antibacterial material comprises doped g-C3N4, graphene and nano silicon dioxide, the proportion of the doped g-C3N4 is not less than 92.5wt%, and the doped g-C3N4 is doped with multiple of boron / silicon / carbon / phosphorus / oxygen / sulfur.

[0018] By adopting the above technical scheme, the doped g-C3N4 has antibacterial properties, and after being compounded and added with graphene and nano silicon dioxide, the antibacterial properties of the innermost pipe layer of the pipe material are improved, and the smoothness of the surface of the pipe material is also improved under the condition of controlling the amount, thereby reducing the water pressure loss.

[0019] Optionally, the number of the pipe material is at least two, and the thickness of the innermost pipe layer is 2-3mm.

[0020] By adopting the above technical scheme, the thickness of the innermost pipe layer of the multi-layer pipe material is 2-3mm, which is suitable in cost and convenient in production under the condition of ensuring low pressure drop and low noise.

[0021] Optionally, there is a bonding layer between the innermost pipe layer and the adjacent pipe layer of the outer layer, the thickness of the bonding layer is 0.2-0.4mm, and the bonding layer is obtained by coating, and the coating material comprises the following raw materials in mass ratio,

[0022] Polytetrafluoroethylene: polydimethylsiloxane = 1: (1.2-1.6);

[0023] The polytetrafluoroethylene is a powder with a particle size of 300-500nm.

[0024] By adopting the technical scheme, the pipe layer of the outer layer of the multi-layer pipe is combined with the pipe layer of the inner layer in a plastic wrapping form. In actual production, the pipe layer of the inner layer is generally obtained by directly extruding and molding and then air drying, and the outer surface of the pipe layer of the inner layer absorbs water. When the pipe layers are wrapped, a small cavity formed by water evaporation exists at the interface between the two pipe layers, and the structural strength of the transition zone of the two pipe layers is weakened. The bonding layer is obtained by coating a glue coating containing polytetrafluoroethylene and polydimethylsiloxane. After the coating is coated, the polydimethylsiloxane promotes the migration of water in the pipe layer, absorbs the water on the surface of the pipe layer and the water migrated out of the pipe layer. On the other hand, the water on the surface of the pipe layer and the water migrated out of the pipe layer is beneficial to the curing of the coating. Therefore, the inside of the coated coating is cured first, and the bonding strength between the bonding layer and the pipe of the inner layer is high during the curing promoted by the water.

[0025] At the same time, the coating has good compatibility with the molten PPR material, and the bonding strength of the outer layer is also strong. When the obtained multi-layer pipe is impacted by the outside world, the transition between the outer pipe layer and the inner pipe is not easy to crack, so that the multi-layer pipe has high overall impact resistance.

[0026] Optionally, the molecular weight of the polydimethylsiloxane in the coating is 4000-5000.

[0027] By adopting the technical scheme, the coating has moderate viscosity, is convenient to coat, and the multi-layer pipe obtained after the coating is used has good impact resistance.

[0028] Optionally, the coating further comprises SEBS powder in an amount of 21-26.3wt% of the mass of polytetrafluoroethylene.

[0029] By adopting the technical scheme, the materials of the two pipe layers in the multi-layer pipe are different, and the densities are different. The difference in the transmission rate of sound waves between the two pipe layers will cause part of the sound waves to be reflected and mixed, and the sound waves will increase the noise when transmitted.

[0030] In the present application, a specific amount of SEBS is added to the coating. Without reducing the strength of the bonding layer itself, the bonding strength between the bonding layer and the inner pipe layer, and the bonding strength between the bonding layer and the outer pipe layer, the sound waves reflected and mixed between the pipe layers and the sound waves of water flow are absorbed, and the noise generated by the water flow in the pipe is reduced.

[0031] Optionally, the particle size of the SEBS powder is 400-500nm.

[0032] By adopting the technical scheme, the noise reduction effect is good.

[0033] In summary, the present application has at least the following beneficial effects:

[0034] 1. Adding the hydrophobic material of the present application to the pipe or the innermost layer of the pipe ensures that the pipe is non-toxic and harmless to the conveying medium water, thereby reducing the friction of the water medium on the pipe, reducing the flow rate and pressure loss, and ensuring stable water flow and low noise;

[0035] 2. Antibacterial materials are added to this application, among which doped g-C3N4 has antibacterial properties. When compounded with graphene and nano-silica, it not only improves the antibacterial properties of the innermost layer of the pipe, but also improves the smoothness of the pipe surface and reduces water pressure loss while controlling its dosage.

[0036] 3. There is a bonding layer between the innermost layer of the multi-layer pipe and the outer and adjacent layers. The bonding layer is coated with an adhesive coating containing polytetrafluoroethylene and polydimethylsiloxane, which promotes the migration of moisture from the pipe layer and absorbs the moisture that migrates from the surface of the pipe layer. When solidified under the promotion of this moisture, the bonding layer and the inner layer of the pipe have a high bonding strength. At the same time, the coating has good compatibility with molten PPR material, which can make the outer layer bonding strength also strong. When the resulting multi-layer pipe is subjected to external impact, the transition between the outer and inner layers of the pipe is not easy to crack, making the multi-layer pipe as a whole reflect strong impact resistance;

[0037] 4. Adding a specific amount of SEBS to the coating can absorb the sound waves reflected and mixed between the pipe layers and the sound waves of the flowing water without reducing the impact resistance of the pipe, thereby reducing the noise generated by the water flow in the pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Attachment Figure 1 This is a schematic diagram of the structure of the PPR pipe in Example 1.

[0039] Reference numerals:

[0040] 1. Inner tube layer; 2. Bonding layer; 3. Outer tube layer. DETAILED DESCRIPTION

[0041] Example 1

[0042] As attached Figure 1 As shown, a super-hydrophobic PPR pipe is a double-layer pipe, comprising an inner pipe layer 1 and an outer pipe layer 3, with a bonding layer 2 sandwiched between the inner and outer pipe layers 1 and 3. The thickness of the inner and outer pipe layers 1 and 3 can be set according to the actual pipe diameter standard. Here, the inner pipe layer 1 has an inner diameter of 25 mm, a thickness of 2.5 mm, and the outer pipe layer 3 has a thickness of 5 mm.

[0043] The inner tube layer 1 is formed by melt extrusion after mixing PPR, masterbatch, hydrophobic material and antibacterial material. The weight proportions of the raw materials are as follows: 90 parts of PPR, 6.8 parts of masterbatch, 3 parts of hydrophobic material and 4.5 parts of antibacterial material.

[0044] The color master batch is obtained by mixing, melting and extruding nanometer titanium dioxide, PPR, oleic acid amide and PE wax in a mass ratio of 2.5:0.75:0.05:0.5.

[0045] The hydrophobic material is obtained by mixing silicon rubber, fluorocarbon and polypropylene in a mass ratio of 0.8:1.1:1.

[0046] The antibacterial material is a mixture of doped g-C3N4, graphene and nanometer silicon dioxide. The mass ratio of doped g-C3N4, graphene and nanometer silicon dioxide is 92.5:4.3:3.2.

[0047] The doped g-C3N4 is obtained by gas phase deposition method. By adjusting the gas phase composition, the doped g-C3N4 is doped with 0.13wt% boron, 0.04wt% silicon, 0.07wt% phosphorus and 0.26wt% oxygen.

[0048] The thickness of the bonding layer 2 is 0.5mm, which is obtained by coating.

[0049] The coating is obtained by mixing polytetrafluoroethylene, polydimethylsiloxane and SEBS powder in a mass ratio of 1:1.56:0.258. The polytetrafluoroethylene is a powder with a particle size of 300-500nm, the polydimethylsiloxane has a molecular weight of 4000-5000, and the SEBS powder has a particle size of 400-500nm.

[0050] The outer tube layer 3 is coated on the outside of the bonding layer 2, and its components are PPR 92wt%, nanometer titanium dioxide 7wt%, oleic acid amide 0.2wt% and PE wax 0.8wt%.

[0051] Examples 2-3

[0052] A super-hydrophobic PPR pipe, similar to Example 1, differs in the amount and parameters of the inner tube layer raw materials, as shown in Table 1.

[0053] Table 1. Part of the raw material amount and parameter table of the inner tube layer of Examples 1-3

[0054] Comparative Example 1

[0055] A PPR pipe, similar to Example 2, differs in that no hydrophobic material is added to the inner tube layer of the PPR pipe of Comparative Example 1, and the other components and proportions are the same.

[0056] Comparative Examples 2-4

[0057] A PPR pipe, similar to Example 2, differs in that the proportions of silicon rubber, fluorocarbon and polypropylene in the hydrophobic material are different, as shown in Table 2.

[0058] Table 2. Hydrophobic material component table of Comparative Examples 2-4

[0059]

[0060] Example 4

[0061] A super-hydrophobic PPR pipe, similar to Example 2, except that in Example 4 the hydrophobic material is a mixture of nano-silica, carbon fluoride, and polypropylene in a mass ratio of 0.8:1.1:1.

[0062] Example 5

[0063] A super-hydrophobic PPR pipe, similar to Example 2, except that in Example 5 the nano-titanium dioxide in the inner pipe layer is not formulated into a color master batch, and an equal mass of nano-titanium dioxide is used instead of the color master batch to mix with the PPR in the inner pipe layer to obtain the inner pipe layer.

[0064] A super-hydrophobic PPR pipe, similar to Example 2, except that in Example 6 no antibacterial material is added to the inner pipe layer of the PPR pipe, and the other components and proportions are the same.

[0065] Examples 7-10

[0066] A super-hydrophobic PPR pipe, similar to Example 2, except that the amount of antibacterial material in the inner pipe layer of the PPR pipe is different, and the specific differences are shown in Table 3 below.

[0067] Table 3. Raw material usage parameters for the inner pipe layer in Examples 7-10

[0068]

[0069] Examples 11-14

[0070] A super-hydrophobic PPR pipe, similar to Example 2, except that the components and amounts of components in the antibacterial material in the inner pipe layer of the PPR pipe are different, and the specific differences are shown in Table 4 below.

[0071] Table 4. Component and component amount parameters for the antibacterial material in Examples 11-14

[0072]

[0073] Example 15

[0074] A super-hydrophobic PPR pipe, similar to Example 2, except that there is no binding layer, and the outer pipe layer is directly plastic-coated outside the inner pipe layer.

[0075] Examples 16-29

[0076] A super-hydrophobic PPR pipe was prepared in a similar manner as in Example 2, except that the coating component of the bonding layer was used in different amounts and had different properties. The specific differences are shown in Table 5.

[0077] Table 5. Coating component of the bonding layer used in Examples 16-29 and the component property parameters

[0078] The pipes obtained in Examples 1-29 and Comparative Examples 1-4 were tested for flow rate, pipe noise, and inner pipe surface bacterial performance. The impact resistance of Examples 1-3 and Examples 15-29 was also tested.

[0079] Flow rate test: A sample pipe with an inner diameter of 25 mm, an inner pipe layer thickness of 2.5 mm, a bonding layer thickness of 0.5 mm, and an outer pipe layer thickness of 5 mm was selected. The pipe was connected to form a 100 m pipeline, one end of which was connected to a 0.25 MPa water supply, and the water flow was maintained. The water pressure at a distance of 80 m from the water inlet was measured, and the water pressure drop ratio (in thousandths) was calculated.

[0080] Pipe noise test: A sample pipe with an inner diameter of 25 mm, an inner pipe layer thickness of 2.5 mm, a bonding layer thickness of 0.5 mm, and an outer pipe layer thickness of 5 mm was selected. A 5 m section of the pipe was inclined at an angle of 45° and connected to a 0.25 MPa water pipeline. The sound level of the water flow at a distance of 2.5 m from the pipe wall was measured, and the average value was recorded after 1 h of testing.

[0081] Inner pipe surface bacterial performance test: The test was conducted according to JC / T 939-2004, and the results were expressed in terms of antibacterial rate. According to JC / T 939-2004, products with an antibacterial rate of not less than 90% can be reported as having antibacterial effects, and products with an antibacterial rate of not less than 99% can be reported as having strong antibacterial effects.

[0082] Impact resistance: The test was conducted according to the non-destructive sample testing method of GB / T 18743.1-2022 Method A.

[0083] The test results are shown in Table 6.

[0084] Table 6. Test results of Examples 1-29 and Comparative Examples 1-4

[0085]

[0086]

[0087] In combination with the above table, it can be seen from Comparative Example 2 and Comparative Example 1 that the pressure drop and noise of Example 2 are obviously smaller than those of Comparative Example 1. This is because the hydrophobic material is added to the inner pipe layer, which improves the friction coefficient of the surface of the inner pipe layer and water, weakens the wall sticking effect of water, and reduces the contact between water and the inner pipe layer. Thus, the situation that the faster the water flow, the greater the pressure drop through the same pipe, and the greater the noise, is avoided, and the water flow pressure drop is small, the noise is low, and thus the water flow speed can be kept stable and the noise environment is low even in the case of large water flow.

[0088] In combination with Example 1 and Example 3, it can be seen that the hydrophobic material of the present application has good applicability to PPR pipe materials.

[0089] It can be seen from Comparative Example 2 and Comparative Examples 2-4 that the improvement of the inner pipe layer of the PPR pipe material by the hydrophobic material added in the present application is realized by the synergistic effect of polypropylene, carbon fluoride, and silicone rubber. In Comparative Examples 2-4, the performance effect of Example 2 cannot be achieved due to the lack of one of the three.

[0090] In combination with Example 4, it can be seen that the hydrophobic material can also be composed of polypropylene, carbon fluoride, and nano-silicon dioxide.

[0091] It can be seen from Comparative Example 5 and Example 2 that the color powder-nano titanium dioxide configured into color master batch and then added can make the color powder mix uniformly with PPR, and the color of the pipe layer is more uniform. At the same time, for the present application, attention is paid to the contact and friction of the surface of the inner pipe layer with water medium. The color powder-nano titanium dioxide configured into color master batch and then added can also make the material of the surface of the inner pipe layer more uniform, reduce friction, reduce water flow capacity loss, and stabilize water flow. For example, the pressure drop and noise of Example 2 are lower than those of Example 5.

[0092] In combination with Example 2 and Example 6, it can be seen that the antibacterial material compounded by doping g-C3N4, graphene, and nano-silicon dioxide is also added to the inner pipe layer in the present application. The doped g-C3N4 has good antibacterial property, and the addition of graphene and nano-silicon dioxide not only makes the doped g-C3N4 mix more uniformly with PPR, avoids the influence of doped g-C3N4 on the low pressure drop and low noise performance of the pipe material of the present application, but also further improves the low pressure drop and low noise performance of the pipe material of the present application. For example, the antibacterial property of Example 2 with the addition of the antibacterial material is obviously improved, and the pressure drop and noise are also lower than those of Example 6.

[0093] It can be seen from Examples 2 and 6-10 that the amount of the antibacterial material in the present application is 3.1-4.6 parts in Example 8 to meet the antibacterial performance requirements of the pipe; the amount in Example 2 meets the strong antibacterial performance requirements of the pipe; when the amount in Example 9 is higher than that in Example 2, the pipe still has strong antibacterial performance, but the pressure drop and noise of the pipe slightly increase, which is because the antibacterial material is an inorganic material, and the combination of graphene and nanosilica alleviates the adverse effects, but too much addition will still cause adverse effects on the contact and friction between the inner pipe layer surface and water; for the detection structure in Example 10, the pipe still has strong antibacterial performance, but the pressure drop and noise of the pipe increase more obviously; therefore, the amount of the antibacterial material in the present application should not be too small or too large, and the amount is 3.1-4.6 parts in Example 8, Example 9, and the range therebetween.

[0094] As mentioned above, the adverse effects of graphene and nanosilica on the low pressure drop and low noise performance of the pipe in the present application are restricted by the proportion of the three, and it can be seen from Examples 11-12 that the proportion of doped g-C3N4 in the antibacterial material is 92.5-95wt%, which obtains the best antibacterial effect, and the adverse effects of graphene and nanosilica on doped g-C3N4 can be effectively alleviated.

[0095] It can be seen from Examples 2 and 13-14 that the doping elements of doped g-C3N4 can be multiple of boron / silicon / carbon / phosphorus / oxygen / sulfur.

[0096] The present application also adds a bonding layer obtained by coating a mixture of polytetrafluoroethylene and polydimethylsiloxane paint to the quality inspection of the innermost pipe layer and the adjacent outer pipe layer of the multilayer PPR pipe.

[0097] It can be seen from Examples 15-18 that Examples 16-18 with the bonding layer significantly improve the impact resistance of the pipe compared with Example 15 without the bonding layer, which is because the outer pipe layer of the multilayer pipe is combined with the inner pipe layer in a plastic wrapping form, and the inner pipe layer is generally obtained by extrusion molding, water cooling, and air drying in actual production, and part of the outer surface of the inner pipe layer absorbs water, so that there is a small cavity formed by water evaporation at the interface between the two layers during plastic wrapping, which weakens the structural strength of the transition zone between the two layers; the bonding layer is obtained by coating an adhesive paint containing polytetrafluoroethylene and polydimethylsiloxane, and after coating, the polydimethylsiloxane promotes the migration of water in the pipe layer, absorbs the water on the surface of the pipe layer, and on the other hand, the water on the surface of the pipe layer and the pipe layer outwardly migrating is conducive to the curing of the paint, so that the inside of the coated paint is cured first, and the bonding strength between the bonding layer and the inner pipe layer is high during the curing promoted by the water.

[0098] The enhancement effect of the combined layer on the impact resistance of the multilayer PPR pipe is related to the particle size of polytetrafluoroethylene and the relative molecular weight of polydimethylsiloxane. The particle size of polytetrafluoroethylene as a solid component of the coating determines the strength of the combined layer itself and also affects the bonding strength of the combined layer and the two pipe layers by affecting the contact between the materials. The relative molecular weight of polydimethylsiloxane affects the viscosity of the coating, the penetration of the coating into the two PPR pipe layers, the guiding effect of the coating on the migration of moisture in the two PPR pipe layers, the curing strength of the combined layer, and the bonding strength of the combined layer and the two pipe layers. As shown in Examples 16 and 19-23, the particle size of polytetrafluoroethylene in the coating of the combined layer of the application is 300-500 nm, and the relative molecular weight of polydimethylsiloxane is 4000-5000.

[0099] As shown in Examples 2 and 19, SEBS is added to the coating of the combined layer of Example 2, which is different from Example 19. The difference in material and density between the two pipe layers of the multilayer pipe and the difference in the transmission rate of sound waves between the two pipe layers can cause some sound waves to be reflected and mixed, which can increase the noise when the sound waves are transmitted.

[0100] In the application, SEBS is added to the coating to absorb the reflected and mixed sound waves between the pipe layers and the sound waves of the water flow, thereby reducing the noise generated by the water flow in the pipe. At the same time, the strength of the combined layer itself, the bonding strength between the combined layer and the inner pipe layer, and the bonding strength between the combined layer and the outer pipe layer are not reduced. As shown in Example 2 compared with Example 19, the noise is significantly reduced.

[0101] At the same time, SEBS is added to the coating, and the amount of SEBS needs to be controlled. Too little cannot achieve the effect, and too much can reduce the strength of the combined layer itself and the bonding strength between the combined layer and the pipe layer. As shown in Examples 2 and 24-27, the amount of SEBS added to the coating is 21-26.3 wt% of polytetrafluoroethylene, which is the best. The particle size of SEBS also affects the noise reduction effect. As shown in Examples 2 and 28-29, the particle size of SEBS is 400-500 nm, which is the best.

[0102] The specific embodiments are only an explanation of the application and are not a limitation of the application. Those skilled in the art can make modifications to the embodiments without creative contribution as long as the modifications are within the scope of the claims of the application.

Claims

1. A super hydrophobic PPR pipe, characterized in that: It is a double-layer pipe, which includes an inner pipe layer and an outer pipe layer, and a bonding layer is sandwiched between the inner and outer pipe layers. The thickness of the inner and outer pipe layers can be set according to the actual pipe diameter standard; here, the inner pipe layer has an inner diameter of 25mm, the inner pipe layer thickness is 2.5mm, and the outer pipe layer thickness is 5mm; The inner tube layer is formed by melt extrusion after mixing PPR, masterbatch, hydrophobic material and antibacterial material. The weight proportions of the raw materials are as follows: PPR 94.2 parts, masterbatch 13.75 parts, hydrophobic material 4.2 parts and antibacterial material 4.5 parts; The masterbatch is prepared by mixing nano-titanium dioxide, PPR, oleamide and PE wax in a mass ratio of 6.3:1.8:0.25:1.2 and melt-extruding to form granules; The hydrophobic material is obtained by mixing silicone rubber, carbon fluoride, and polypropylene in a mass ratio of 0.8:1.1:1; The antibacterial material is a mixture of doped g-C3N4, graphene and nano-silica, with a mass ratio of doped g-C3N4, graphene and nano-silica of 92.5:4.3:3.2; The doped g-C3N4 is produced by vapor deposition. By adjusting the gas phase composition, the doped g-C3N4 is doped with 0.13wt% boron, 0.04wt% silicon, 0.07wt% phosphorus, and 0.26wt% oxygen. The thickness of the bonding layer 2 is 0.5 mm and is obtained by coating; The coating is obtained by mixing polytetrafluoroethylene, polydimethylsiloxane and SEBS powder in a mass ratio of 1:1.56:0.

258. The polytetrafluoroethylene is a powder of 300-500nm, the molecular weight of polydimethylsiloxane is 4000-5000, and the particle size of SEBS powder is 400-500nm; the outer tube layer is plastic-coated on the outside of the bonding layer, and its components are PPR 92wt%, nano titanium dioxide 7wt%, oleic acid amide 0.2wt% and PE wax 0.8wt%.

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