A PPR pipe with copper resistance performance and its preparation method

Abstract

The present invention discloses a PPR pipe with copper resistance and a preparation method thereof, relating to the technical field of building water supply PPR pipes. An anti-copper masterbatch comprises the following components: modified activated carbon; random copolymer polypropylene resin; antioxidant and copper inhibitor 1024; the modified activated carbon comprises activated carbon and amino / amine-modified crosslinked chitosan nanospheres loaded on the activated carbon. A PPR pipe with copper resistance comprises a PPR outer layer and an anti-copper functional inner layer, and the anti-copper functional inner layer comprises PPR resin and the anti-copper masterbatch. By the synergistic effect of adding activated carbon loaded with amino / amine-modified crosslinked chitosan nanospheres and antioxidant and copper inhibitor 1024 to the inner layer of the PPR pipe, the present invention is beneficial to improving the ability to adsorb and complex copper ions and has long-term effectiveness, thus effectively solving the "copper harm" problem of PPR pipes, and the formed PPR pipes meet the sanitary performance requirements for transporting drinking water.

Description

Technical Field

[0001] The present invention relates to the technical field of building water supply PPR pipes, and particularly relates to a PPR pipe with copper resistance and a preparation method thereof. Background Art

[0002] PPR pipes are a commonly used water supply pipeline material. Due to their good heat resistance, pressure resistance, corrosion resistance, and easy processability, they are widely used in fields such as construction, chemical industry, and food. PPR pipes are usually connected by hot melt welding with pipe fittings with copper inserts to form a water conveyance pipeline. Existing research has shown that polyolefin materials are extremely sensitive to copper ions, and in the presence of copper ions, the degradation and aging of materials such as PE and PP will be accelerated. When the water contains copper ions, under the combined aging effect of hot water, oxygen, and copper ions for a long time, "copper damage" problems will occur in PPR pipes, resulting in leakage, pipe bursting, etc. during the use of the pipes.

[0003] In order to solve the problem of "copper damage" in olefin materials, currently, mainly copper-resistant agents are added. Chinese Patent with application number 201310413501.8 discloses a polypropylene composite material containing a polyphosphate copper-resistant agent and a preparation method thereof. A blend is processed by adding a polyphosphate copper-resistant agent, an inorganic filler, an antioxidant, an ultraviolet absorber, and a flame retardant to polypropylene; Chinese Patent with application number 201310411050.4 discloses a polypropylene composite material containing an amino carboxylic acid type copper-resistant agent and a preparation method thereof. Different from the Chinese Patent with application number 201310413501.8, the copper-resistant agent is an amino carboxylic acid type copper-resistant agent; the polypropylene composite materials prepared by the above two copper-resistant agents are applicable to the insulation coating materials of copper core cables, but their ability to adsorb free copper ions is weak and they are limited in application in PPR pipes.

[0004] How to solve the "copper damage" problem of PPR pipes and improve the copper resistance of PPR pipes is an important research direction for the modification of polypropylene materials, which has important scientific significance and practical value. Therefore, a new solution is needed to improve the copper corrosion resistance of PPR pipes, so as to extend their service life and reduce the later maintenance cost. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a PPR pipe with copper resistance and a preparation method thereof. The present invention effectively solves the "copper damage" problem of PPR pipes by adding activated carbon loaded with cross-linked chitosan nanoparticles modified with amino / amine groups and copper-resistant antioxidant 1024 in the inner layer of the PPR pipe, which is beneficial to improving the ability to adsorb and complex copper ions and has long-term effectiveness, and the formed PPR pipe meets the sanitary performance requirements for conveying drinking water.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides an anti - copper masterbatch, comprising the following components in parts by weight:

[0008] 6 - 22 parts of modified activated carbon; 33 - 76.5 parts of random copolymer polypropylene resin; 5 - 10 parts of antioxidant and anti - copper agent 1024; 5 - 16 parts of titanium dioxide; 3 - 8 parts of pigment; 0.5 - 2 parts of compatibilizer; 0.5 - 2 parts of dispersant; 3 - 5 parts of lubricant; 0.5 - 2 parts of coupling agent;

[0009] The modified activated carbon comprises activated carbon and amino / amine - modified cross - linked chitosan nanospheres loaded on the activated carbon; the activated carbon is pre - treated by alkali - acid treatment.

[0010] In the present invention, the random copolymer polypropylene resin serves as the carrier resin of the anti - copper masterbatch, enabling the anti - copper additives to be evenly distributed therein and having high compatibility with the PPR resin, which is beneficial to better dispersion of the anti - copper additives and to improving the pressure resistance of PPR pipes. The activated carbon can adsorb copper ions and at the same time adsorb the cross - linked chitosan nanospheres loaded with amino / amine modification, thereby enabling the latter to be evenly dispersed into the resin and synergistically adsorb copper ions in water. The antioxidant and anti - copper agent 1024 has antioxidant and anti - copper properties, but as the antioxidant effect is consumed, the anti - copper effect gradually weakens. When used in combination with the activated carbon containing cross - linked chitosan nanospheres loaded with amino / amine modification, the anti - copper effect can be significantly improved.

[0011] Therefore, by adding activated carbon loaded with amino / amine - modified cross - linked chitosan nanospheres and antioxidant and anti - copper agent 1024 to the inner layer of the PPR pipe, through the synergistic action of the amino / amine - modified cross - linked chitosan nanospheres, activated carbon, and antioxidant and anti - copper agent 1024, it is beneficial to improve the ability to adsorb and complex copper ions and has long - term effectiveness, thus effectively solving the "copper harm" problem of PPR pipes, and the formed PPR pipes meet the sanitary performance requirements for transporting drinking water.

[0012] In the present invention, titanium dioxide can improve the whiteness and covering power of the masterbatch, and improve the appearance color and light transmittance; the pigment colors the masterbatch and improves the appearance color. The compatibilizer improves the compatibility of the modified activated carbon, antioxidant and anti - copper agent 1024 with the random copolymer polypropylene carrier resin, and improves the stability and processing performance of the mixture. The dispersant can promote the uniform dispersion of the pigment in the resin and prevent it from agglomerating again. The melting point of the dispersant is lower than that of the resin, it has good compatibility with the resin and good affinity with the pigment. The lubricant reduces the frictional resistance of the mixed materials during the processing process, thereby improving the processability of the anti - copper additives, pigment, and carrier resin. The coupling agent further enhances the binding of the activated carbon, antioxidant and anti - copper agent 1024, pigment, etc. with the carrier resin and improves the filler dispersion.

[0013] In the amino / amine modified cross-linked chitosan nano-microspheres of the present invention, " / " represents an "or" relationship.

[0014] Preferably, the mass ratio of the amino / amine-modified cross-linked chitosan nano-microspheres to the activated carbon in the modified activated carbon is 1:(50-80).

[0015] Preferably, the particle size of the amino / amine-modified cross-linked chitosan nanoparticles is 10-30 nm.

[0016] Preferably, the amino / amine group includes at least one of an aminoethyl group, an aminopropyl group, an aminovinyl group, and an ethylenediamine group.

[0017] Further preferably, the amino / amine-modified cross-linked chitosan nano-microspheres include epichlorohydrin amino-modified cross-linked chitosan nano-microspheres and / or polyethyleneimine-modified cross-linked chitosan nano-microspheres.

[0018] The cross-linked chitosan nano-microspheres modified with epichlorohydrin amine groups have a particle size of 10-25 nm and were purchased from Qingdao University; the cross-linked chitosan nano-microspheres modified with polyethyleneimine have a particle size of 20-30 nm and were purchased from Xi'an Qiyue.

[0019] Preferably, the deacetylation degree of the chitosan is 80%-90%.

[0020] Preferably, the activated carbon includes at least one of coconut shell activated carbon, fruit shell activated carbon, wood activated carbon and coal activated carbon.

[0021] Preferably, the particle size of the activated carbon is 250-400 mesh.

[0022] Preferably, the activated carbon pretreatment method comprises the following steps:

[0023] The activated carbon is soaked in an alkaline solution for 1-2 hours; then the alkali-washed activated carbon is soaked at 80-85°C for 2-3 hours; then the acid-washed activated carbon is washed with pure water; finally, it is dried at 110-120°C for 10-12 hours to obtain the pretreated activated carbon.

[0024] In the present invention, after the activated carbon is washed with alkali, not only can impurities be removed, but also the pores of the activated carbon will become well-developed. After pickling, the pores of the activated carbon can be effectively enlarged, the specific surface area can be increased, and at the same time, metal ions and other impurities on the surface of the activated carbon can be removed, and the basic groups can be neutralized. Moreover, after pickling, there will be more -COOH and -OH functional groups on the surface of the activated carbon, which are more likely to combine with the cross-linked chitosan microspheres modified with amino / amine groups. At the same time, the activated carbon with more active groups on the surface enhances its compatibility and dispersibility with the polyethylene resin. Therefore, through alkali-acid treatment, it is beneficial to improve the ability of the activated carbon to load chitosan microspheres, can make the pores of the activated carbon well-developed, and the functional groups added on the surface are more likely to combine with the cross-linked chitosan modified with amino / amine groups.

[0025] Preferably, the acid includes at least one of hydrochloric acid, sulfuric acid, and nitric acid.

[0026] Preferably, the preparation method of the modified activated carbon includes the following steps:

[0027] S1: Add the cross-linked chitosan nanospheres modified with amino / amine groups into an organic solvent, stir evenly, and dissolve to obtain a colloidal solution;

[0028] S2: Add the pretreated activated carbon into the colloidal solution, perform ultrasonic oscillation, and soak for 5 - 10 h;

[0029] S3: Filter the soaked activated carbon, and finally dry the filtered activated carbon at 80 - 90 °C for 2 - 5 h to obtain the modified activated carbon.

[0030] Preferably, the titanium dioxide includes at least one of rutile titanium dioxide and anatase titanium dioxide, and rutile titanium dioxide is preferred.

[0031] Preferably, the pigment includes at least one of phthalocyanine green, pigment yellow, bright orange, and carbon black.

[0032] Preferably, the compatibilizer includes at least one of maleic anhydride grafted polypropylene and acrylic acid grafted polypropylene.

[0033] Preferably, the dispersant includes at least one of fatty acids, aliphatic amides, and aliphatic esters.

[0034] Preferably, the lubricant includes at least one of PE wax and Fischer-Tropsch wax.

[0035] Preferably, the coupling agent includes at least one of titanate coupling agents, silane coupling agents, and aluminate coupling agents.

[0036] Preferably, the random copolymer polypropylene resin is ethylene-propylene random copolymer polypropylene, with an ethylene content of 4%-9%, a melt index of 7-9 g / 10min, and a density of 0.895-0.905 g / m 3 .

[0037] Second, the present invention also provides a method for preparing an anti-copper masterbatch, which includes the following steps:

[0038] (1) Mix the modified activated carbon, compatibilizer, and 1 / 2 of the dispersant evenly to obtain the first mixture;

[0039] (2) Mix the pigment, 1 / 2 of the dispersant, and the lubricant evenly to obtain the second mixture;

[0040] (3) Mix the random copolymer polypropylene resin, antioxidant and copper inhibitor 1024, titanium dioxide, coupling agent, the first mixture, and the second mixture evenly to obtain the third mixture;

[0041] (4) Melt-extrude the third mixture with a twin-screw extruder at an extrusion temperature of 150-190°C to obtain the anti-copper masterbatch.

[0042] Through a three-step mixing process, the present invention pre-mixes and disperses the activated carbon and pigment and then mixes them with the resin, etc., which can solve the problem of poor compatibility and difficult dispersion between the activated carbon, pigment, and resin.

[0043] Third, the present invention also provides a PPR pipe with anti-copper performance, which includes a PPR outer layer and an anti-copper functional inner layer, and the anti-copper functional inner layer includes PPR resin and an anti-copper masterbatch.

[0044] Preferably, the mass ratio of the PPR resin to the anti-copper masterbatch is (90-97):(3-10).

[0045] Preferably, the thickness ratio of the outer layer to the inner layer is: PPR outer layer: anti-copper functional inner layer = 9:(0.8-2.5).

[0046] Preferably, the PPR resin is a random copolymer polypropylene resin.

[0047] Preferably, the PPR outer layer includes PPR resin and a masterbatch.

[0048] Fourth, the present invention also provides a method for preparing a PPR pipe with anti-copper performance, which includes the following steps:

[0049] (1) Mix the PPR resin and the anti-copper masterbatch evenly to obtain the raw material for the anti-copper functional inner layer; mix the PPR resin and the masterbatch evenly to obtain the raw material for the PPR outer layer;

[0050] (2) Feed the raw materials for the copper-resistant functional inner layer and the PPR outer layer into the single-screw extruders for the inner and outer layers respectively, and co-extrude them through a double-layer die. The extrusion temperature is 210 - 240 °C.

[0051] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0052] (1) Through the pretreated activated carbon in the present invention, impurities and metal ions on the surface of the activated carbon can be removed, and active group functional groups are generated on the surface, which are easily dispersed into the matrix resin; at the same time, the pores of the activated carbon can be developed, the surface area can be increased, and the amino / amine group-modified crosslinked chitosan microspheres can be more easily combined with the functional groups on the surface of the activated carbon.

[0053] (2) The amino / amine group-modified crosslinked chitosan nanospheres in the present invention have a small particle size, are prone to agglomeration, and are not easily uniformly dispersed into the resin. First, load them onto the outer surface and internal ablation pores of the treated activated carbon particles. The activated carbon with polar groups on the surface is more easily dispersed into the matrix resin, so that the amino / amine group-modified crosslinked chitosan nanospheres achieve a good dispersion effect in the matrix resin.

[0054] (3) The amino / amine group-modified crosslinked chitosan nanospheres in the present invention are effectively loaded onto the activated carbon and form a stable adsorption layer on the surface and in the pores of the activated carbon. This can enhance the adsorption effect of the activated carbon on copper ions, and improve its adsorption capacity and adsorption rate. At the same time, the amine functional groups of the crosslinked chitosan can also form complexes with copper ions, increasing the selectivity and effect of adsorption.

[0055] (4) The implementation of segmented mixing in the preparation of the copper-resistant masterbatch in the present invention can effectively improve the agglomeration phenomenon of the activated carbon loaded with amino / amine group-modified crosslinked chitosan nanospheres and the pigment in the resin, and improve the compatibility with the resin and the dispersibility in the resin matrix. Brief Description of the Drawings

[0056] Figure 1 is a schematic structural diagram of the PPR pipe described in the present invention. 1 is the copper-resistant functional inner layer, and 2 is the PPR outer layer. Specific Embodiments

[0057] To better illustrate the purpose, technical solution and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. However, the protection scope and implementation manner of the present invention are not limited thereto.

[0058] The materials, reagents, etc. used in the following embodiments are, unless otherwise specified, reagents and materials that can be obtained from commercial channels.

[0059] PPR resin: T4401, Dushanzi Petrochemical, density 0.895 g / m 3, the tensile yield stress is 22.4 MPa;

[0060] Activated carbon: wood-based activated carbon, 325 mesh, Hongzhiyuan;

[0061] Epichlorohydrin amine-modified crosslinked chitosan nanospheres: with a particle size of 10 - 25 nm, customized by Qingdao University;

[0062] Random copolymer polypropylene resin: DY-W725EF, Dushanzi Petrochemical, ethylene content 4.8 - 5.3%, melt index 7 - 8 g / 10 min, density 0.897 g / m 3 ;

[0063] Antioxidant and copper inhibitor 1024: Irganox MD1024, BASF;

[0064] Titanium dioxide: LR108, Longbai;

[0065] Pigments: Phthalocyanine Green (Green SG1017) and Pigment Yellow (Yellow 29RP), Guangzhou Xie Cai;

[0066] Compatibilizer: Maleic anhydride grafted polypropylene AT2937, Mitsui Chemicals, Japan;

[0067] Dispersant: Vinyl bisstearamide EBS-P200, Indonesia Chaoyang Chemical;

[0068] Lubricant: Zinc stearate, commercially available;

[0069] Coupling agent: Silane coupling agent KH550, commercially available.

[0070] In the following examples and comparative examples, the sources of each substance are the above-mentioned substances.

[0071] Example 1

[0072] This example discloses a copper-resistant masterbatch, which comprises the following components in parts by weight:

[0073] 13 parts of modified activated carbon; 55 parts of random copolymer polypropylene resin; 8 parts of antioxidant and copper inhibitor 1024; 11 parts of titanium dioxide; 6 parts of pigments; 1 part of compatibilizer; 1 part of dispersant; 4 parts of lubricant; 1 part of coupling agent.

[0074] The modified activated carbon includes activated carbon and amino / amine-modified crosslinked chitosan nanospheres loaded on the activated carbon. The mass ratio of the amino / amine-modified crosslinked chitosan nanospheres to the activated carbon is 1:50; the particle size of the amino / amine-modified crosslinked chitosan nanospheres is 10 nm.

[0075] The preparation method of the modified activated carbon comprises the following steps:

[0076] S1: Soak the activated carbon in sodium hydroxide solution for 1.5 h; then soak the alkali-washed activated carbon at 85 °C for 2 h; then wash the activated carbon washed with 5% hydrochloric acid solution by pure water; finally, dry it at 120 °C for 10 h to obtain the pretreated activated carbon;

[0077] S2: Add the amino / amine-modified crosslinked chitosan into ethanol solvent, stir evenly to dissolve and obtain a colloidal solution;

[0078] S3: Add the pretreated activated carbon into the colloidal solution, perform ultrasonic oscillation and soak for 8 h;

[0079] S4: Filter the soaked activated carbon through a filter screen to remove the excess solution, and finally put the filtered activated carbon into a low-temperature oven for rapid drying, with the drying temperature being 85 °C and the time being 4 h, thus obtaining the modified activated carbon.

[0080] This embodiment also discloses a preparation method of an anti-copper masterbatch, including the following steps:

[0081] (1) Mix the modified activated carbon, compatibilizer and 1 / 2 of the dispersant, and stir with a high-speed mixer for 6 min to obtain mixture one, so that the activated carbon is pre-mixed evenly with the compatibilizer and dispersant, and the activated carbon is evenly wrapped by the compatibilizer and dispersant, which can improve the compatibility with the carrier resin;

[0082] (2) Then mix the pigment, 1 / 2 of the dispersant and the lubricant, and stir with a high-speed mixer for 6.5 min to obtain mixture two. Through high-speed mixing and stirring treatment with the dispersant and lubricant, the powder pigment can be effectively dispersed evenly to improve the agglomeration of the powder pigment;

[0083] (3) Then mix the random copolymerized polypropylene resin, antioxidant and copper inhibitor 1024, titanium dioxide, coupling agent, mixture one and mixture two, and stir with a high-speed mixer for 8 min to obtain mixture three;

[0084] (4) Feed mixture three into the twin-screw main machine through a feeder, set the extrusion temperature from the feeding port to the die to 150 - 180 °C, melt and extrude the strip, and cut it into pellets after cooling in a water bath to obtain the anti-copper masterbatch.

[0085] This embodiment also discloses a PPR pipe with anti-copper performance, including a PPR outer layer 2 and an anti-copper functional inner layer 1, and the structure is as Figure 1 shown. The thickness ratio of the PPR outer layer to the anti-copper functional inner layer is 9:1, and it is a dn20×2.8 - S3.2 specification pipe.

[0086] The copper-resistant functional inner layer comprises PPR resin and a copper-resistant masterbatch, and the mass ratio of the PPR resin to the copper-resistant masterbatch is 94:6. The PPR outer layer comprises PPR resin and a masterbatch, and the mass ratio of the two is 98:2.

[0087] This embodiment also discloses a preparation method of a PPR pipe with copper-resistant performance, comprising the following steps:

[0088] (1) Mix the PPR resin and the copper-resistant masterbatch evenly to obtain the raw material for the copper-resistant functional inner layer; mix the PPR resin and the masterbatch evenly to obtain the raw material for the PPR outer layer;

[0089] (2) Feed the raw material for the copper-resistant functional inner layer and the raw material for the PPR outer layer into a single-screw extruder for the inner and outer layers respectively, and co-extrude through a double-layer die. The extrusion temperature is 210 - 240 °C, thus obtaining a PPR pipe with copper-resistant performance.

[0090] Example 2

[0091] A copper-resistant masterbatch comprises the following components in parts by weight:

[0092] 6 parts of modified activated carbon; 70.5 parts of random copolymer polypropylene resin; 102410 parts of antioxidant and copper inhibitor; 6 parts of titanium dioxide; 3 parts of pigment; 0.5 part of compatibilizer; 0.5 part of dispersant; 3 parts of lubricant; 0.5 part of coupling agent.

[0093] The modified activated carbon comprises activated carbon and amino / amine-modified crosslinked chitosan nanospheres loaded on the activated carbon. The mass ratio of the amino / amine-modified crosslinked chitosan nanospheres to the activated carbon is 1:80; the particle size of the amino / amine-modified crosslinked chitosan nanospheres is 30 nm.

[0094] The preparation method of the modified activated carbon and the preparation method of the copper-resistant masterbatch are the same as those in Example 1.

[0095] A PPR pipe with copper-resistant performance comprises a PPR outer layer and a copper-resistant functional inner layer, and the structure is as Figure 1 shown. The copper-resistant functional inner layer comprises PPR resin and a copper-resistant masterbatch, and the mass ratio of the PPR resin to the copper-resistant masterbatch is 90:10. The PPR outer layer comprises PPR resin and a masterbatch, and the mass ratio of the two is 98:2.

[0096] The preparation method of a PPR pipe with copper-resistant performance is the same as that in Example 1.

[0097] Example 3

[0098] A copper-resistant masterbatch comprises the following components in parts by weight:

[0099] 22 parts of modified activated carbon; 38 parts of random copolymer polypropylene resin; 5 parts of antioxidant and copper inhibitor 1024; 16 parts of titanium dioxide; 8 parts of pigment; 2 parts of compatibilizer; 2 parts of dispersant; 5 parts of lubricant; 2 parts of coupling agent.

[0100] The preparation method of the modified activated carbon and the preparation method of the anti - copper masterbatch are the same as those in Example 1.

[0101] A PPR pipe with anti - copper performance, including a PPR outer layer and an anti - copper functional inner layer, has a structure as Figure 1 shown. The anti - copper functional inner layer includes PPR resin and anti - copper masterbatch, and the mass ratio of PPR resin to anti - copper masterbatch is 97:3. The PPR outer layer includes PPR resin and masterbatch, and the mass ratio of the two is 98:2.

[0102] The preparation method of a PPR pipe with anti - copper performance is the same as that in Example 1.

[0103] Example 4

[0104] The difference from Example 1 is that when the activated carbon is pretreated by alkali - acid treatment, the alkali - washed activated carbon is soaked in a 5% sulfuric acid solution by mass fraction at 85 °C for 1.5 h, and the others are the same as in Example 1.

[0105] Example 5

[0106] The difference from Example 1 is that when the activated carbon is pretreated by alkali - acid treatment, the alkali - washed activated carbon is soaked in a 4% nitric acid solution by mass fraction at 85 °C for 1.5 h, and the others are the same as in Example 1.

[0107] Comparative Example 1

[0108] This comparative example provides a PPR pipe, and its raw material composition is PPR of Dushanzi Petrochemical T4401.

[0109] Comparative Example 2

[0110] This comparative example provides a PPR pipe, and its raw material composition is PPR of Dushanzi Petrochemical T4401, and 0.5 part of antioxidant and copper inhibitor 1024 is added.

[0111] Comparative Example 3

[0112] This comparative example provides a PPR pipe, and its raw material composition is PPR of Dushanzi Petrochemical T4401, and 0.5 part of commercially available antioxidant 1010 and 0.5 part of commercially available antioxidant 168 are added.

[0113] Comparative Example 4

[0114] The difference from Example 1 is that antioxidant and copper inhibitor 1024 is not added to the raw materials of the anti - copper masterbatch, and the others are the same as in Example 1.

[0115] Comparative Example 5

[0116] The difference from Example 1 is that no modified activated carbon is added to the raw materials of the anti-copper masterbatch, and the rest is the same as Example 1.

[0117] Comparative Example 6

[0118] The difference from Example 1 is that the activated carbon does not carry amino / amine-modified cross-linked chitosan nanoparticles, and the rest is the same as Example 1.

[0119] Comparative Example 7

[0120] The difference from Example 1 is that the activated carbon is loaded with cross-linked chitosan nano-microspheres not modified with amino / amine groups, that is, the activated carbon is loaded with cross-linked chitosan nano-microspheres, and the rest is the same as Example 1.

[0121] Comparative Example 8

[0122] The difference from Example 1 is that the activated carbon is not pre-treated with alkali or acid, and the rest is the same as Example 1.

[0123] Comparative Example 9

[0124] The difference from Example 1 is that the activated carbon is only treated with alkali in advance, and the rest is the same as Example 1.

[0125] Comparative Example 10

[0126] The difference from Example 1 is that the activated carbon is only treated with acid in advance, and the rest is the same as Example 1.

[0127] Comparative Example 11

[0128] The difference from Example 1 is that the raw materials used in the preparation of the anti-copper masterbatch are simultaneously put into a high-speed mixer and mixed and stirred at one time. The rest is the same as Example 1.

[0129] Performance Testing

[0130] The performance of the PPR pipes obtained in the above examples and comparative examples were tested respectively, and the specific test items, test methods and results are as follows:

[0131] (1) Low temperature drop hammer impact test

[0132] The test method is as follows:

[0133] ① Sampling: Randomly select 1 pipe (3 meters / piece or 4 meters / piece).

[0134] ②Sample preparation and treatment: After the pipe material is naturally and completely cooled, cut the pipe for testing within 6 hours after it is taken off the production line; cut the pipe material into sample pipes about 15 cm long, ensuring that the sample pipes are intact, without obvious deformation, and the end faces are free of burrs; place the sample pipes in a water-filled sink and treat them in a 0°C refrigerator or a 0°C cooling box for 1 hour.

[0135] ③Testing: Use a falling weight impact testing machine for the test instrument, select a d25 type hammer head for testing. After the sample pipe is conditioned, take out the sample pipe from the water bath in turn and complete the test within 10 seconds. Test 10 samples for each type of pipe; set the falling weight height at 1 m, the initial weight of the falling weight is 1.0 kg, and increase the weight by 0.5 kg each time, and record the results of the cracking of the tested sample pipes.

[0136] (2)Copper resistance test of PPR pipes

[0137] The test method is as follows:

[0138] Prepare tap water with a high content of copper ions, with a copper ion content of 10 mg / L. Pour the tap water containing copper ions into the PPR test sample pipe, seal both ends of the PPR pipe, and immerse the PPR pipe in a 60°C insulation water tank. Take samples every fifteen days and test the oxidation induction time OIT of the PPR pipe and the change of the PPR pipe's hydrostatic pressure resistance (95°C, 22 h, 4.3 MPa hydrostatic stress). Among them, the oxidation induction time is tested according to the GB / T 19466.6-2009 standard; the hydrostatic pressure test is tested according to the GB / T 6111-2003 standard.

[0139] The test results of the low-temperature falling weight performance and copper resistance of the PPR pipes prepared in the above examples and comparative examples are shown in Tables 1-5 below.

[0140] Table 1 Test results of low-temperature falling weight and oxidation induction time of PPR pipes

[0141]

[0142] Table 2 Test results of hydrostatic pressure performance of PPR pipes

[0143]

[0144] Table 3 Test results of hydrostatic pressure performance of PPR pipes

[0145]

[0146] Table 4 Test results of hydrostatic pressure performance of PPR pipes

[0147]

[0148] Table 5 Test results of hydrostatic pressure performance of PPR pipes

[0149]

[0150] As can be seen from Table 1-5, in the present invention, activated carbon loaded with amino / amine group-modified crosslinked chitosan nanospheres and copper-resistant antioxidant 1024 are added to the PPR pipe to form a copper-resistant functional layer, which improves the ability to adsorb and complex copper ions and significantly enhances the copper-resistant and anti-aging performance of the PPR pipe. The activated carbon is treated with acid and alkali and mixed with pigments in stages, which can effectively improve the agglomeration phenomenon in the resin, enhance the compatibility with the resin and the dispersion in the resin matrix.

[0151] In Comparative Examples 1-3, antioxidant and copper-resistant agent 1024, antioxidant 1010 and 168 were directly added to the PPR pipe, and the initial oxidation induction time was significantly increased, enhancing the antioxidant and anti-aging performance. However, after 60 days, the oxidation induction time decreased significantly. It is analyzed that this may be because copper ions accelerated the degradation and aging of PPR, and the ability of pure antioxidant and copper-resistant agent 1024 to complex copper ions is limited, and antioxidant 1010 and 168 have no copper-resistant aging performance. Under the long-term action of heat, oxygen and copper ions, the pressure resistance of the pipe decreases, increasing the risk of pipe explosion.

[0152] In Comparative Examples 6-10, in the case of not adding activated carbon loaded with amino / amine group-modified crosslinked chitosan nanospheres, adding activated carbon with unloaded amino / amine group-modified crosslinked chitosan nanospheres, and adding activated carbon without alkali-acid treatment, the ability of activated carbon to adsorb and complex copper ions decreases, the degradation and aging of PPR are obvious, and the heat resistance and hydraulic pressure resistance decrease; at the same time, Comparative Examples 8-10 show that without alkali-acid treatment of activated carbon, the dispersion of activated carbon in the PPR substrate is uneven, the low-temperature impact performance decreases, and the amount of amino / amine group-modified crosslinked chitosan nanospheres loaded decreases, and the copper-resistant and anti-aging performance also decreases.

[0153] In Comparative Example 11, the method of one-time mixing and stirring was adopted, and the dispersion of activated carbon loaded with amino / amine group-modified crosslinked chitosan nanospheres, antioxidant and copper-resistant agent 1024 and pigments became poor, resulting in agglomeration. The low-temperature impact performance of the pipe was significantly deteriorated, and the antioxidant and anti-aging performance was also significantly reduced.

[0154] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. An anti-copper masterbatch, characterized in that: The composition comprises the following components in parts by weight: Modified activated carbon 6-22 parts; random copolymer polypropylene resin 33-76.5 parts; antioxidant and anti-copper agent 1024 5-10 parts; titanium dioxide 5-16 parts; pigment 3-8 parts; compatibilizer 0.5-2 parts; dispersant 0.5-2 parts; lubricant 3-5 parts; coupling agent 0.5-2 parts; The modified activated carbon comprises activated carbon and amino / amine-modified cross-linked chitosan nano-microspheres loaded on the activated carbon; the activated carbon is pre-treated with alkali and acid; The pretreatment method steps of the activated carbon are as follows: Soak the activated carbon in an alkaline solution for 1-2 hours; then soak the activated carbon after alkali washing at 80-85°C for 2-3 hours; then wash the activated carbon after acid washing with pure water; finally bake at 110-120°C for 10-12 hours to obtain the pretreated activated carbon; The preparation method of the modified activated carbon comprises the following steps: S1: adding amino / amine-modified cross-linked chitosan nanoparticles into an organic solvent, stirring evenly, and dissolving to obtain a colloidal solution; S2: Add the pretreated activated carbon into the colloidal solution, ultrasonically vibrate, and soak for 5-10 hours; S3: filtering the soaked activated carbon, and finally drying the filtered activated carbon at 80-90°C for 2-5h to obtain modified activated carbon; The raw materials used in the preparation of the anti-copper masterbatch are mixed in stages: the modified activated carbon is mixed evenly with the compatibilizer and 1 / 2 of the dispersant to obtain a mixture 1; the pigment, 1 / 2 of the dispersant and the lubricant are mixed evenly to obtain a mixture 2; the random copolymer polypropylene resin, the antioxidant and anti-copper agent 1024, titanium dioxide, the coupling agent, the mixture 1 and the mixture 2 are mixed evenly.

2. The anti-copper masterbatch according to claim 1, characterized in that: The mass ratio of the amino / amine-modified cross-linked chitosan nano-microspheres to the activated carbon in the modified activated carbon is 1:(50-80).

3. The anti-copper masterbatch according to claim 1, characterized in that: The particle size of the amino / amine-modified cross-linked chitosan nano-microspheres is 10-30 nm.

4. The anti-copper masterbatch according to claim 1, characterized in that: At least one of (a) to (d): (a) the amino group / amine group includes at least one of aminoethyl, aminopropyl, aminovinyl, and ethylenediamine; (b) the deacetylation degree of the chitosan is 80%-90%; (c) the activated carbon comprises at least one of coconut shell activated carbon, fruit shell activated carbon, wood activated carbon and coal activated carbon; (d) The particle size of the activated carbon is 250-400 mesh.

5. The anti-copper masterbatch according to claim 1, characterized in that: At least one of (a) to (g): (a) the titanium dioxide comprises at least one of rutile titanium dioxide and anatase titanium dioxide; (b) the pigment comprises at least one of phthalocyanine green, pigment yellow, brilliant orange and carbon black; (c) the compatibilizer comprises at least one of maleic anhydride grafted polypropylene and acrylic acid grafted polypropylene; (d) the dispersant comprises at least one of fatty acids, fatty amides, and fatty esters; (e) the lubricant comprises at least one of PE wax and Fischer-Tropsch wax; (f) the coupling agent comprises at least one of a titanate coupling agent, a silane coupling agent, and an aluminate coupling agent; (g) The random copolymer polypropylene resin is ethylene-propylene binary random copolymer polypropylene.

6. A method for preparing the anti-copper masterbatch according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) The modified activated carbon, the compatibilizer and 1 / 2 of the dispersant are uniformly mixed to obtain a mixture 1; (2) Evenly mix the pigment, 1 / 2 of the dispersant and the lubricant to obtain a mixture 2; (3) uniformly mixing the random copolymer polypropylene resin, the antioxidant and anti-copper agent 1024, titanium dioxide, the coupling agent, the mixture 1 and the mixture 2 to obtain the mixture 3; (4) The mixed material is melt-extruded in a twin-screw machine at a temperature of 150-190°C to obtain an anti-copper masterbatch.

7. A PPR pipe with copper resistance, characterized in that: It comprises a PPR outer layer and an anti-copper functional inner layer, wherein the anti-copper functional inner layer comprises a PPR resin and the anti-copper masterbatch according to any one of claims 1 to 5.

8. A method for preparing a PPR pipe with copper resistance as claimed in claim 7, characterized in that: The following steps are involved: (1) Mix the PPR resin and the anti-copper masterbatch evenly to obtain the anti-copper functional inner layer raw material; mix the PPR resin and the masterbatch evenly to obtain the PPR outer layer raw material; (2) The anti-copper functional inner layer raw material and the PPR outer layer raw material are fed into the inner and outer layer single screw extruders respectively, and co-extruded through a double-layer mold at an extrusion temperature of 210-240°C.

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