PPR fiber composite pipe resistant to low-temperature impact and preparation method thereof

Abstract

The present application relates to a kind of PPR fiber composite pipe of low temperature impact resistance and preparation method thereof.It solves the problem of poor low temperature toughness of PPR pipe in the prior art, which is prone to break after impact.It includes composite pipe body, the circumferential outer wall of composite pipe body is provided with PPR outer layer, the circumferential inner side of PPR outer layer is provided with bacteriostatic scale-resistant PPR inner layer, and impact-resistant reinforcing layer is provided between bacteriostatic scale-resistant PPR inner layer and PPR outer layer, the thickness of impact-resistant reinforcing layer is greater than 33% of the thickness of composite pipe body, and the thickness of bacteriostatic scale-resistant PPR inner layer is greater than 15% of the thickness of composite pipe body.The advantages of the present application are: improve the impact resistance, cold resistance and impact resistance of pipe material, reduce the adhesion of scale, and the setting of antibacterial scale-resistant inner layer can meet the diversified use requirements.

Description

Technical Field

[0001] This invention relates to the field of pipe fittings technology, specifically to a low-temperature impact-resistant PPR fiber composite pipe and its preparation method. Background Technology

[0002] PPR, or random copolymer polypropylene, has advantages over traditional pipes such as cast iron pipes, galvanized steel pipes, and cement pipes. It is energy-saving, material-saving, environmentally friendly, lightweight and high-strength, corrosion-resistant, has a smooth inner wall that does not scale, and is easy to construct and maintain. It also has a service life of up to 50 years and has been widely used since its introduction to China.

[0003] However, PP-R exhibits low-temperature brittleness. At temperatures below 5°C, it is easily damaged by external forces, making construction and transportation inconvenient in cold northern regions during winter. Furthermore, when used as main pipes or risers, PP-R pipes have low rigidity, making them prone to sagging and bending. Their coefficient of linear expansion is three times that of steel, and they are also susceptible to expansion and bending over long distances when hot water is introduced. Existing PP-R fiberglass composite pipes, by introducing fiberglass, have addressed the issues of linear expansion coefficient and rigidity, but this has reduced the pipe's toughness and exacerbated its low-temperature brittleness. In practical use, they are more likely to break under impact at low temperatures. Summary of the Invention

[0004] The purpose of this invention is to address the above-mentioned problems by providing a PPR fiber composite pipe that is resistant to low-temperature impact.

[0005] The purpose of this invention is to address the above-mentioned problems by providing a method for preparing a low-temperature impact-resistant PPR fiber composite pipe.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a low-temperature impact-resistant PPR fiber composite pipe, comprising a composite pipe body, a PPR outer layer on the outer circumferential wall of the composite pipe body, an antibacterial and anti-scaling PPR inner layer on the inner circumferential side of the PPR outer layer, an impact-resistant reinforcing layer between the antibacterial and anti-scaling PPR inner layer and the PPR outer layer, the thickness of the impact-resistant reinforcing layer being greater than 33% of the thickness of the composite pipe body, and the thickness of the antibacterial and anti-scaling PPR inner layer being greater than 15% of the thickness of the composite pipe body.

[0007] In the aforementioned low-temperature impact-resistant PPR fiber composite pipe, the impact-resistant reinforcement layer includes a rigid outer layer connected to the inner wall of the PPR outer layer, a flexible inner layer connected to the outer wall of the antibacterial and anti-scaling PPR inner layer on the circumferential inner side of the rigid outer layer, and several impact-resistant structures between the flexible inner layer and the rigid outer layer.

[0008] In the aforementioned low-temperature impact-resistant PPR fiber composite pipe, the impact-resistant structure includes an arc-shaped flexible part connected to the inner wall of the rigid outer layer, and the arc-shaped flexible part is connected to an arc-shaped rigid part through several support parts. The inner wall of the arc-shaped rigid part is connected to the flexible inner layer, and a filling gap is provided between adjacent support parts, and the filling gap is filled with flexible insulating material.

[0009] In the aforementioned low-temperature impact resistant PPR fiber composite pipe, the outer circumferential wall of the PPR outer layer is wrapped with a wear-resistant layer, and the inner circumferential wall of the antibacterial and anti-scaling PPR inner layer is provided with a protective inner layer.

[0010] In the aforementioned low-temperature impact-resistant PPR fiber composite pipe, the outer PPR layer is made of PPR material, which is a resin with a density of 0.9–0.92 g / cm3 and a melt flow index of 0.2–0.5 g / 10min.

[0011] The outer layer of PPR material contains nickel oxide and nano-montmorillonite, with a mass ratio of nickel oxide to nano-montmorillonite between 1:3 and 1:2, and the mass fraction of nano-montmorillonite in the pipe is 1-3%.

[0012] The addition of nickel oxide and nano-montmorillonite materials is used to improve the low-temperature impact resistance of PPR pipes. Its working principle mainly includes the following aspects:

[0013] 1. Intercalation Effect of Nano-Montmorillonite: Nano-montmorillonite is a layered silicate mineral whose layered structure can be inserted into a PPR matrix using organic modifiers to form an "intercalated" composite material. This structure enhances the interaction between the PPR molecular chains and the montmorillonite layers, improving the interlayer bonding strength of the material. At low temperatures, the intercalated structure can effectively prevent rapid crack propagation, improving the material's impact resistance and low-temperature impact resistance.

[0014] 2. Toughening Mechanism of Nano-Montmorillonite: The layers of nano-montmorillonite act as stress concentrators in the PPR matrix. When the material is subjected to impact, the layers can disperse and absorb impact energy, thereby improving the toughness of the material. In addition, the thermal conductivity of montmorillonite also helps the PPR matrix to dissipate heat more evenly, reducing stress concentration caused by local temperature differences, and further improving the material's low-temperature impact resistance.

[0015] 3. Strengthening effect of nickel oxide: As a nanoparticle additive, nickel oxide can improve the microstructure of the PPR matrix through its nanoscale effect, such as increasing crystallinity, refining grain size, and reducing defects. These improvements in microstructure can enhance the tensile strength, flexural strength, impact strength, and other mechanical properties of the material, and strengthen the low-temperature impact resistance of PPR pipes.

[0016] 4. Barrier effect of nickel oxide: Nickel oxide particles form a "barrier" in the PPR matrix, which can prevent crack propagation and improve the material's resistance to crack propagation. Especially at low temperatures, nickel oxide particles can reduce the movement of PPR molecular chains, reduce brittle transition, and improve the material's low-temperature toughness.

[0017] 5. Synergistic Effect: The synergistic effect of nano-montmorillonite and nickel oxide can further improve the low-temperature impact resistance of PPR pipes. The "intercalation" structure and toughening mechanism of montmorillonite work together with the strengthening and barrier effects of nickel oxide to improve the material's impact resistance and low-temperature performance.

[0018] In summary, the addition of nickel oxide and nano-montmorillonite can improve the low-temperature impact resistance of PPR pipes. The mechanism of action includes the intercalation effect and toughening mechanism of nano-montmorillonite, the strengthening and barrier effects of nickel oxide, and the synergistic effect between the two. In practical applications, the most suitable nickel oxide and nano-montmorillonite should be selected based on a comprehensive consideration of specific process conditions, performance requirements, and cost, and their effectiveness in improving the low-temperature impact resistance of PPR pipes should be verified through experiments.

[0019] The antibacterial and antiscaling PPR inner layer 12 is made of antibacterial and antiscaling PPR material, and its weight components include: 100 parts of PPR resin, 2-5 parts of antibacterial masterbatch, and 0.1-0.5 parts of antiscaling masterbatch; wherein, the antiscaling masterbatch is made by introducing one or more of polytetrafluoroethylene fine powder, siloxane, siloxane copolymer, and silicone lubricant into PPR and granulating, and the antibacterial masterbatch is made by introducing zinc-based antibacterial agent or silver-based antibacterial agent into PPR and granulating.

[0020] The impact-resistant reinforcing layer 13 comprises the following components by weight: 100 parts PPR resin, 30-60 parts glass fiber, 5-15 parts toughening agent, 10-15 parts compatibilizer, 1.5-2 parts anti-aging masterbatch, 10-40 parts PERT resin, and 5-10 parts block copolymer polypropylene; the glass fiber is continuous long glass fiber with a retained length of 400-800µm, the toughening agent is thermoplastic elastomer POE, and the compatibilizer is polypropylene-maleic anhydride graft.

[0021] According to the above-mentioned low-temperature impact resistant PPR fiber composite pipe, a method for preparing a low-temperature impact resistant PPR fiber composite pipe is provided, which includes the following steps:

[0022] S1. Preparation of antibacterial and antiscaling layer;

[0023] S2, preparation of impact-resistant reinforcement layer 13;

[0024] S3. PPR resin material is selected as the outer layer 11 of PPR;

[0025] S4, composite pipe extrusion.

[0026] Step S1 specifically includes the following steps:

[0027] S11. Weigh 100 parts of PPR material, 5 parts of zinc ion antibacterial masterbatch, and 0.4 parts of anti-scaling masterbatch by weight, and place them in a high-speed mixer for stirring for 4-6 minutes.

[0028] S12. Using a high-temperature twin-screw extruder, the processing temperature is set to 170-200℃ for melt blending and granulation to prepare an antibacterial and antiscaling PPR composite material.

[0029] Step S2 specifically includes the following steps:

[0030] S21. Weigh 100 parts PPR, 11 parts compatibilizer, 20 parts PERT resin, 6 parts toughening agent, 6 parts block copolymer polypropylene, and 1.6 parts antioxidant masterbatch by weight, and place them in a high-speed mixer and stir for 9-11 minutes.

[0031] S22. Use a high-compound twin-screw extruder for melt blending, and introduce 50 parts of long glass fiber through side feeding. Set the processing temperature to 180-210℃, extrude and pelletize to obtain a high-impact reinforced PPR composite material, and store it for later use after drying.

[0032] Step S4 specifically includes the following steps:

[0033] S41. The antibacterial and antiscaling PPR composite material, the high impact-strength reinforced PPR composite material, and the PPR material obtained in steps S1-S3 are respectively placed in three screw extruders as raw materials for the antibacterial and antiscaling PPR inner layer 12, the impact-strength reinforced layer 13, and the PPR outer layer 11, and then melt co-extruded. The co-extruded temperature is set to 180-230℃.

[0034] S42. Control the screw speed of the three single-screw extruders to control the extrusion amount of the three-layer material, so that the thickness ratio of the inner layer, middle layer and outer layer is 2:5:3.

[0035] S43, after being shaped by a sizing sleeve, cooled, drawn and cut, a low-temperature impact resistant PPR fiber composite pipe is obtained.

[0036] The high-impact reinforced PPR composite material from step S22 is separately injection molded into notched impact specimens and bending specimens using an injection molding machine.

[0037] Compared with existing technologies, the advantages of this invention are:

[0038] 1. The addition of POE can form an island structure. Its toughening mechanism conforms to the crazing-shear band theory, which can disperse the applied impact stress and generate a large number of crazing and shear bands, further absorbing a large amount of energy and improving the impact resistance of the pipe.

[0039] 2. PERT itself has good temperature resistance and impact resistance. The addition of PERT can fundamentally improve the low-temperature impact resistance of PPR. Compared with adding only POE, PERT can replace part of the POE dosage. The blending of PPR / POE / PERT further improves the impact resistance of the pipe, comprehensively improves the various properties of PPR material, and greatly reduces costs.

[0040] 4. As a propylene-ethylene block copolymer, PPB can improve the compatibility between PPR and PERT, ensuring that the internal pressure resistance of the pipe does not decrease.

[0041] 5. By introducing antibacterial masterbatch and anti-scaling masterbatch, the hygienic performance and smoothness of the inner wall of the pipe are improved, and the adhesion of scale is reduced.

[0042] 6. This invention has a reasonable design and simple structure. It can improve the cold resistance and impact resistance of fiberglass composite pipes, and the antibacterial and anti-scaling inner layer can meet diverse usage needs. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0044] Figure 2 This is a schematic diagram of the impact-resistant structure in this invention;

[0045] Figure 3 This is a flowchart of the preparation method in this invention;

[0046] In the figure: Composite pipe body 1, PPR outer layer 11, antibacterial and anti-scaling PPR inner layer 12, impact-reinforcing layer 13, rigid outer layer 131, flexible inner layer 132, impact-resistant structure 2, arc-shaped flexible 21, support part 22, arc-shaped rigid part 23, gap filling 24, wear-resistant layer 111, protective inner layer 121. Detailed Implementation

[0047] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0048] like Figure 1-3As shown, 1. A low-temperature impact-resistant PPR fiber composite pipe includes a composite pipe body 1, a PPR outer layer 11 is provided on the outer wall of the composite pipe body 1, an antibacterial and anti-scaling PPR inner layer 12 is provided on the inner side of the PPR outer layer 11, and an impact-resistant reinforcing layer 13 is provided between the antibacterial and anti-scaling PPR inner layer 12 and the PPR outer layer 11. The thickness of the impact-resistant reinforcing layer 13 is greater than 33% of the thickness of the composite pipe body 1, and the thickness of the antibacterial and anti-scaling PPR inner layer 12 is greater than 15% of the thickness of the composite pipe body.

[0049] The antibacterial and antiscaling PPR inner layer 12 accounts for 20% of the total thickness of the composite pipe, the impact-resistant reinforcing layer 13 accounts for 50% of the total thickness of the composite pipe, and the PPR outer layer 11 accounts for 30% of the total thickness of the composite pipe.

[0050] The antibacterial and scale-resistant PPR inner layer 12 mainly prevents bacterial growth and makes the inner wall of the pipe smooth, maintaining the advantages of no scaling and large water flow.

[0051] The glass fiber added to the impact-resistant reinforcement layer 13 enhances the mechanical properties, and the addition of POE and PERT can improve the reduction in toughness caused by the addition of glass fiber.

[0052] The outer layer 11 of PPR ensures that the composite pipe can inherit the excellent welding performance of PPR pipe.

[0053] The impact-resistant reinforcement layer 13 includes a rigid outer layer 131 connected to the inner wall of the PPR outer layer 11. A flexible inner layer 132 connected to the outer wall of the antibacterial and anti-scaling PPR inner layer 12 is provided on the inner side of the rigid outer layer 131. Several impact-resistant structures 2 are provided between the flexible inner layer 132 and the rigid outer layer 131.

[0054] In detail, the impact-resistant structure 2 includes an arc-shaped flexible part 21 connected to the inner wall of the rigid outer layer 131, and the arc-shaped flexible part 21 is connected to an arc-shaped rigid part 23 via a plurality of support parts 22. The inner wall of the arc-shaped rigid part 23 is connected to the flexible inner layer 132, and a filling gap 24 is provided between adjacent support parts 22, and the filling gap 24 is filled with flexible insulating material.

[0055] The rigid and flexible structures are combined with the support 22 to form a high-strength impact resistance. Secondly, flexible insulating material is filled in the gap 24 to improve the low-temperature resistance. PPR composite material is extruded between the two connected impact-resistant structures 2 to improve the structural strength.

[0056] Furthermore, the outer PPR layer 11 is wrapped with a wear-resistant layer 111 around its outer wall, and the antibacterial and anti-scaling PPR inner layer 12 is provided with a protective inner layer 121 around its inner wall.

[0057] Preferably, the PPR outer layer 11 is made of PPR material, which is a resin with a density of 0.9 to 0.92 g / cm3 and a melt index of 0.2 to 0.5 g / 10min;

[0058] Among them, the PPR material of the outer layer 11 contains nickel oxide and nano-montmorillonite, with a mass ratio of nickel oxide to nano-montmorillonite between 1:3 and 1:2, and the mass fraction of nano-montmorillonite in the pipe is 1-3%.

[0059] The addition of nickel oxide and nano-montmorillonite materials is used to improve the low-temperature impact resistance of PPR pipes. Its working principle mainly includes the following aspects:

[0060] 1. Intercalation Effect of Nano-Montmorillonite: Nano-montmorillonite is a layered silicate mineral whose layered structure can be inserted into a PPR matrix using organic modifiers to form an "intercalated" composite material. This structure enhances the interaction between the PPR molecular chains and the montmorillonite layers, improving the interlayer bonding strength of the material. At low temperatures, the intercalated structure can effectively prevent rapid crack propagation, improving the material's impact resistance and low-temperature impact resistance.

[0061] 2. Toughening Mechanism of Nano-Montmorillonite: The layers of nano-montmorillonite act as stress concentrators in the PPR matrix. When the material is subjected to impact, the layers can disperse and absorb impact energy, thereby improving the toughness of the material. In addition, the thermal conductivity of montmorillonite also helps the PPR matrix to dissipate heat more evenly, reducing stress concentration caused by local temperature differences, and further improving the material's low-temperature impact resistance.

[0062] 3. Strengthening effect of nickel oxide: As a nanoparticle additive, nickel oxide can improve the microstructure of the PPR matrix through its nanoscale effect, such as increasing crystallinity, refining grain size, and reducing defects. These improvements in microstructure can enhance the tensile strength, flexural strength, impact strength, and other mechanical properties of the material, and strengthen the low-temperature impact resistance of PPR pipes.

[0063] 4. Barrier effect of nickel oxide: Nickel oxide particles form a "barrier" in the PPR matrix, which can prevent crack propagation and improve the material's resistance to crack propagation. Especially at low temperatures, nickel oxide particles can reduce the movement of PPR molecular chains, reduce brittle transition, and improve the material's low-temperature toughness.

[0064] 5. Synergistic Effect: The synergistic effect of nano-montmorillonite and nickel oxide can further improve the low-temperature impact resistance of PPR pipes. The "intercalation" structure and toughening mechanism of montmorillonite work together with the strengthening and barrier effects of nickel oxide to improve the material's impact resistance and low-temperature performance.

[0065] In summary, the addition of nickel oxide and nano-montmorillonite can improve the low-temperature impact resistance of PPR pipes. The mechanism of action includes the intercalation effect and toughening mechanism of nano-montmorillonite, the strengthening and barrier effects of nickel oxide, and the synergistic effect between the two. In practical applications, the most suitable nickel oxide and nano-montmorillonite should be selected based on a comprehensive consideration of specific process conditions, performance requirements, and cost, and their effectiveness in improving the low-temperature impact resistance of PPR pipes should be verified through experiments.

[0066] The antibacterial and antiscaling PPR inner layer 12 is made of antibacterial and antiscaling PPR material, and its weight components include: 100 parts of PPR resin, 2-5 parts of antibacterial masterbatch, and 0.1-0.5 parts of antiscaling masterbatch; wherein, the antiscaling masterbatch is made by introducing one or more of polytetrafluoroethylene fine powder, siloxane, siloxane copolymer, and silicone lubricant into PPR and granulating, and the antibacterial masterbatch is made by introducing zinc-based antibacterial agent or silver-based antibacterial agent into PPR and granulating.

[0067] The impact-resistant reinforcing layer 13 comprises the following components by weight: 100 parts PPR resin, 30-60 parts glass fiber, 5-15 parts toughening agent, 10-15 parts compatibilizer, 1.5-2 parts anti-aging masterbatch, 10-40 parts PERT resin, and 5-10 parts block copolymer polypropylene. The glass fiber is a continuous long glass fiber that has undergone impregnation modification treatment, resulting in better dispersibility. The retained length of the glass fiber is 400-800µm. The toughening agent is thermoplastic elastomer POE, and the compatibilizer is polypropylene-maleic anhydride graft, which can further improve the compatibility between the polymer and the glass fiber.

[0068] A method for preparing a low-temperature impact-resistant PPR fiber composite pipe, comprising the following steps:

[0069] Example 1

[0070] S1. Preparation of antibacterial and antiscaling layer;

[0071] S2, preparation of impact-resistant reinforcement layer 13;

[0072] S3. PPR resin material is selected as the outer layer 11 of PPR;

[0073] S4, composite pipe extrusion.

[0074] Step S1 specifically includes the following steps:

[0075] S11. Weigh 100 parts of PPR material, 5 parts of zinc ion antibacterial masterbatch, and 0.4 parts of anti-scaling masterbatch by weight, and place them in a high-speed mixer for stirring for 4-6 minutes.

[0076] S12. Using a high-temperature twin-screw extruder, the processing temperature is set to 170-200℃ for melt blending and granulation to prepare an antibacterial and antiscaling PPR composite material.

[0077] Step S2 specifically includes the following steps:

[0078] S21. Weigh 100 parts PPR, 11 parts compatibilizer, 20 parts PERT resin, 6 parts toughening agent, 6 parts block copolymer polypropylene, and 1.6 parts antioxidant masterbatch by weight, and place them in a high-speed mixer and stir for 9-11 minutes.

[0079] S22. Use a high-compound twin-screw extruder for melt blending, and introduce 50 parts of long glass fiber through side feeding. Set the processing temperature to 180-210℃, extrude and pelletize to obtain a high-impact reinforced PPR composite material, and store it for later use after drying.

[0080] Step S4 specifically includes the following steps:

[0081] S41. The antibacterial and antiscaling PPR composite material, the high impact-strength reinforced PPR composite material, and the PPR material obtained in steps S1-S3 are respectively placed in three screw extruders as raw materials for the antibacterial and antiscaling PPR inner layer 12, the impact-strength reinforced layer 13, and the PPR outer layer 11, and then melt co-extruded. The co-extruded temperature is set to 180-230℃.

[0082] S42. Control the screw speed of the three single-screw extruders to control the extrusion amount of the three-layer material, so that the thickness ratio of the inner layer, middle layer and outer layer is 2:5:3.

[0083] S43, after being shaped by a sizing sleeve, cooled, drawn and cut, a low-temperature impact resistant PPR fiber composite pipe is obtained.

[0084] The high-impact reinforced PPR composite material from step S22 is separately injection molded into notched impact specimens and bending specimens using an injection molding machine.

[0085] Example 2

[0086] This embodiment provides a composite tube and its test strip, which has the same structure as that in Embodiment 1 and a similar preparation method, except that the amount of PERT added is 10 parts by weight.

[0087] Example 3

[0088] This embodiment provides a composite tube and its test strip, which has the same structure as that in Embodiment 1 and a similar preparation method, except that the amount of POE added is 10 parts by weight.

[0089] Comparative Example 1

[0090] This embodiment provides a composite tube and its test strip, which has the same structure and preparation method as in Embodiment 1, except that POE is not added.

[0091] Comparative Example 2

[0092] This embodiment provides a composite tube and its test strip, which has the same structure and preparation method as in Embodiment 1, except that PPB is not added.

[0093] Comparative Example 3

[0094] This embodiment provides a composite tube and its test strip, which has the same structure and preparation method as in Embodiment 1, except that PPB and POE are not added.

[0095] Comparative Example 4

[0096] This embodiment provides a composite tube and its test strip, which has the same structure and preparation method as in Embodiment 1, except that PPB and POE are not added, and the amount of PERT added is 10 parts by weight.

[0097] Comparative Example 5

[0098] This embodiment provides a composite tube and its test strip, which has the same structure and preparation method as in Embodiment 1, except that PERT, PPB and POE are not added.

[0099] Comparative Example 6

[0100] This embodiment provides a composite tube and its test strip, which has the same structure as in Example 1 and a similar preparation method. The only difference is that PERT and POE are not added, and the PPR used is replaced with PPB.

[0101] The notched impact specimens obtained in the above embodiments and comparative examples were tested for impact performance according to GB / T1043-2008 standard; bending performance was tested according to GB / T9341-2008 standard; and hydrostatic tests were conducted according to CJT258-2014 standard. To more quickly compare the differences in pipe pressure resistance, a method exceeding the CJT258-2014 standard was used for hydrostatic testing to evaluate internal pressure resistance. The test results are shown in Tables 1 and 2.

[0102] Example 1 7.11 17.23 Hinge damage Example 2 7.62 16.37 Hinge damage Example 3 7.09 19.54 Hinge damage Comparative Example 1 7.76 13.62 Complete destruction Comparative Example 2 4.66 16.91 Hinge damage Comparative Example 3 5.52 13.58 Complete destruction Comparative Example 4 6.23 12.44 Complete destruction Comparative Example 5 8.42 11.19 Complete destruction Comparative Example 6 1.34 13.43 Complete destruction

[0103] Table 1

[0104] Example 1 51.06 2517.11 No cracks or leaks No cracks or leaks Example 2 53.83 2667.87 No cracks or leaks No cracks or leaks Example 3 48.08 2496.09 No cracks or leaks No cracks or leaks Comparative Example 1 52.33 2701.18 No cracks or leaks No cracks or leaks Comparative Example 2 49.59 2488.65 No cracks or leaks No cracks or leaks Comparative Example 3 51.62 2664.30 No cracks or leaks No cracks or leaks Comparative Example 4 53.42 2734.06 No cracks or leaks No cracks or leaks Comparative Example 5 56.39 2980.54 No cracks or leaks No cracks or leaks Comparative Example 6 42.84 2258.09 No cracks or leaks 855h rupture

[0105] Table 2

[0106] As can be seen from Examples 1-3 and Comparative Examples 1-6, various mechanical properties are related to the amount of PERT, PPB, and POE added. By reasonably adjusting the ratio of the three, it can be ensured that the impact performance is improved without significantly reducing the high temperature and pressure resistance of the pipe.

[0107] In summary, the principle of this embodiment is as follows: By setting a PPR outer layer 11, an antibacterial and antiscaling PPR inner layer 12, and an impact-reinforcing layer 13 on the composite pipe body 1, the toughness of the composite pipe is greatly improved while ensuring the original mechanical properties. This solves the problem of easy pipe breakage caused by the low-temperature brittleness of PPR fiberglass pipe. Furthermore, this preparation method can form an island structure by adjusting the pipe components and proportions and adding POE. Its toughening mechanism conforms to the crazing-shear band theory, which can disperse the applied impact stress and generate a large number of crazing and shear bands, further absorbing a large amount of energy and improving the impact resistance of the pipe.

[0108] Secondly, the blending of PPR / POE / PERT further improves the impact resistance of the pipe, comprehensively enhances the various properties of PPR material, and greatly reduces costs;

[0109] Meanwhile, PPB, as a propylene-ethylene block copolymer, can improve the compatibility between PPR and PERT, ensuring that the pipe's internal pressure resistance does not decrease. The introduction of antibacterial and anti-scaling masterbatches improves the pipe's hygienic properties and the smoothness of its inner wall, reducing scale buildup.

[0110] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

[0111] Although this document frequently uses terms such as composite pipe body 1, PPR outer layer 11, antibacterial and antiscaling PPR inner layer 12, impact-reinforcing layer 13, rigid outer layer 131, flexible inner layer 132, impact-resistant structure 2, arc-shaped flexible 21, support part 22, arc-shaped rigid part 23, gap filling 24, wear-resistant layer 111, and protective inner layer 121, the possibility of using other terms is not excluded. The use of these terms is merely for the convenience of describing and explaining the essence of this invention; interpreting them as any additional limitation would contradict the spirit of this invention.

Claims

1. A low-temperature impact-resistant PPR fiber composite pipe, comprising a composite pipe body (1), wherein the outer circumferential wall of the composite pipe body (1) is provided with a PPR outer layer (11), characterized in that, The outer PPR layer (11) is provided with an antibacterial and antiscaling PPR inner layer (12) on its circumferential inner side. An impact-resistant reinforcement layer (13) is provided between the antibacterial and antiscaling PPR inner layer (12) and the outer PPR layer (11). The thickness of the impact-resistant reinforcement layer (13) is greater than 33% of the thickness of the composite pipe body (1), and the thickness of the antibacterial and antiscaling PPR inner layer (12) is greater than 15% of the thickness of the composite pipe body. The PPR outer layer (11) is made of PPR material and contains nickel oxide and nano-montmorillonite material. The mass ratio of nickel oxide to nano-montmorillonite is between 1:3 and 1:2, and the mass fraction of nano-montmorillonite in the pipe is 1-3%. The PPR material is a resin with a density of 0.9-0.92 g / cm3 and a melt index of 0.2-0.5 g / 10min. The antibacterial and antiscaling PPR inner layer (12) is made of antibacterial and antiscaling PPR material, and its weight components include: 100 parts of PPR resin, 2-5 parts of antibacterial masterbatch, and 0.1-0.5 parts of antiscaling masterbatch; wherein, the antiscaling masterbatch is made by introducing one or more of polytetrafluoroethylene fine powder, siloxane, siloxane copolymer, and silicone lubricant into PPR and granulating it, and the antibacterial masterbatch is made by introducing zinc-based antibacterial agent or silver-based antibacterial agent into PPR and granulating it. The impact-resistant reinforcing layer (13) comprises the following components by weight: 100 parts PPR resin, 30-60 parts glass fiber, 5-15 parts toughening agent, 10-15 parts compatibilizer, 1.5-2 parts anti-aging masterbatch, 10-40 parts PERT resin, and 5-10 parts block copolymer polypropylene; the glass fiber is a continuous long glass fiber with a retention length of 400-800µm, the toughening agent is thermoplastic elastomer POE, and the compatibilizer is polypropylene-maleic anhydride graft.

2. The low-temperature impact-resistant PPR fiber composite pipe according to claim 1, characterized in that, The impact-resistant reinforcement layer (13) includes a rigid outer layer (131) connected to the inner wall of the PPR outer layer (11). The rigid outer layer (131) is provided with a flexible inner layer (132) connected to the outer wall of the antibacterial and anti-scaling PPR inner layer (12) on its circumferential inner side. Several impact-resistant structures (2) are provided between the flexible inner layer (132) and the rigid outer layer (131).

3. The low-temperature impact-resistant PPR fiber composite pipe according to claim 2, characterized in that, The impact-resistant structure (2) includes an arc-shaped flexible (21) part connected to the inner wall of the rigid outer layer (131), and the arc-shaped flexible (21) part is connected to an arc-shaped rigid part (23) through a plurality of support parts (22). The inner wall of the arc-shaped rigid part (23) is connected to the flexible inner layer (132), and a filling gap (24) is provided between adjacent support parts (22). The filling gap (24) is filled with flexible insulating material.

4. The low-temperature impact-resistant PPR fiber composite pipe according to claim 1, characterized in that, The outer wall of the PPR outer layer (11) is wrapped with a wear-resistant layer (111), and the inner wall of the antibacterial and anti-scaling PPR inner layer (12) is provided with a protective inner layer (121).

5. The method for preparing the PPR fiber composite pipe according to any one of claims 1-4, characterized in that, Includes the following steps: S1, Preparation of antibacterial and antiscaling PPR inner layer (12); S2, preparation of impact-resistant reinforcement layer (13); S3. PPR resin material is selected as the outer layer of PPR (11). S4, composite pipe extrusion.

6. The method for preparing a low-temperature impact-resistant PPR fiber composite pipe according to claim 5, characterized in that, Step S1 specifically includes the following steps: S11. Weigh 100 parts of PPR material, 5 parts of zinc ion antibacterial masterbatch, and 0.4 parts of anti-scaling masterbatch by weight, and place them in a high-speed mixer for stirring for 4-6 minutes. S12. Using a high-temperature twin-screw extruder, the processing temperature is set to 170-200℃ for melt blending and granulation to prepare an antibacterial and antiscaling PPR composite material.

7. The method for preparing a low-temperature impact-resistant PPR fiber composite pipe according to claim 5, characterized in that, Step S2 specifically includes the following steps: S21. Weigh 100 parts PPR, 11 parts compatibilizer, 20 parts PERT resin, 6 parts toughening agent, 6 parts block copolymer polypropylene, and 1.6 parts antioxidant masterbatch by weight, and place them in a high-speed mixer and stir for 9-11 minutes. S22. Use a high-compound twin-screw extruder for melt blending, and introduce 50 parts of long glass fiber through side feeding. Set the processing temperature to 180-210℃, extrude and pelletize to obtain a high-impact reinforced PPR composite material, and store it for later use after drying.

8. The method for preparing a low-temperature impact-resistant PPR fiber composite pipe according to claim 5, characterized in that, Step S4 specifically includes the following steps: S41. The antibacterial and antiscaling PPR composite material, the high impact-strength reinforced PPR composite material and the PPR material obtained in steps S1-S3 are respectively placed in three screw extruders as raw materials for the antibacterial and antiscaling PPR inner layer (12), the impact-strength reinforced layer (13) and the PPR outer layer (11) for melt co-extrusion, and the co-extrusion temperature is set to 180-230℃. S42. Control the screw speed of the three single-screw extruders to control the extrusion amount of the three-layer material, so that the thickness ratio of the inner layer, middle layer and outer layer is 2:5:

3. S43, after being shaped by a sizing sleeve, cooled, drawn and cut, a low-temperature impact resistant PPR fiber composite pipe is obtained.

9. The method for preparing a low-temperature impact-resistant PPR fiber composite pipe according to claim 5, characterized in that, The high-impact reinforced PPR composite material from step S22 is separately injection molded into notched impact specimens and bending specimens using an injection molding machine.

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