Special color master batch for PE temperature-resistant pipes and pipe fittings and preparation method of special color master batch

Abstract

The invention discloses a special color master batch for PE temperature-resistant pipes and pipe fittings and a preparation method of the special color master batch, and belongs to the technical field of color master batches. The color master batch is prepared from the following components in parts by weight: 40 to 65 parts of carrier resin, 8 to 25 parts of opacifying agent, 1.5 to 2.5 parts of modified composite pigment and 0 to 2 parts of functional additive. The preparation method comprises the following steps: reacting a functional material with a silane compound in an alkaline ethanol solution to form a coating solution, carrying out ultrasonic-assisted mechanical stirring treatment on the coating solution and the composite pigment, and drying and ball-milling to obtain the modified composite pigment. Finally, the pigment, carrier resin, an opacifying agent, an antioxidant, a light stabilizer and the like are subjected to segmented mixing, melt extrusion and granulation, and a finished product is obtained. Compared with the prior art, the dispersity, the interface bonding force and the weather resistance and wear resistance of the pigment are remarkably improved, and the obtained color master batch is uniform in coloring, excellent in stability and particularly suitable for high-performance PE temperature-resistant pipes and pipe fittings.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of color master batch, and particularly relates to a PE temperature-resistant pipe and pipe fitting special color master batch and a preparation method thereof. BACKGROUND

[0002] As an indispensable coloring and functional master batch in modern plastic industry, the performance of color master batch directly determines the appearance quality, use performance and service life of the final plastic product. Especially in the field of polyethylene temperature-resistant pipe and pipe fitting, the requirements for special color master batch are much higher than those for general products. Such pipe materials are long-term served in complex environments such as underground and outdoor, and not only need to bear mechanical stress such as internal pressure and external force impact, but also need to resist long-term thermal oxidation aging, ultraviolet radiation, day and night temperature difference cycle and the continuous action of fluid in the pipe. Therefore, the ideal special color master batch must achieve the balance of multiple technical targets: on the one hand, it must ensure the ultra-fine and stable dispersion of pigments in the polymer matrix to present uniform and bright color, on the other hand, it must give the product excellent weather resistance to resist color fading, and at the same time, it must have excellent wear resistance to maintain surface integrity, and can maintain long-term physical and chemical stability under high temperature processing and use conditions. However, due to the poor compatibility of pigments and resin matrix in traditional color master batch, pigment particles are easy to agglomerate and migrate, which not only causes the decrease of tinting strength and uneven color, but also becomes a stress concentration point to accelerate the environmental aging failure of the material, and becomes a key technical bottleneck restricting the development of high-performance PE pipe.

[0003] To overcome the aforementioned bottlenecks, existing technologies have undergone numerous explorations, but limitations and applicability boundaries still exist. For example, Chinese Patent Publication No. CN119708906A discloses a toluidine red pigment for architectural coatings, which significantly improves weather resistance and dispersibility in coating systems by introducing nano-oxides and organosilicon modifiers. However, this technical solution targets the coating film-forming system, and its pigment carrier, application interface, and performance evaluation standards are fundamentally different from those of masterbatches that need to be melt-dispersed in PE resin and subjected to high-temperature shearing processing. Its technical effects are difficult to directly transfer to the field of plastic coloring. Chinese Patent Publication No. CN119955326A provides a method for preparing an acid and alkali resistant permanent red pigment, which enhances the chemical stability of the pigment through silica coating and hydrophobic treatment with fluorinated silanes. However, its technical focus is on improving the pigment's resistance to acid and alkali corrosion. For key mechanical properties and long-term durability indicators, such as wear resistance, UV aging resistance, and interfacial bonding with macromolecular polyolefins, which are particularly critical for PE pipes, this patent does not provide effective solutions. In addition, Chinese patent publication number CN120137221A relates to a high-performance color masterbatch for automotive engineering plastics, which uses polypropylene as the main carrier and emphasizes mechanical and UV resistance properties. However, polypropylene and polyethylene have very different molecular structures, crystallization behaviors and processing rheological properties. The color masterbatch formulation and process conditions using polypropylene as the carrier cannot be directly applied to PE pressure piping systems that have strict requirements for environmental stress cracking resistance. Furthermore, this solution does not adequately consider the long-term thermal stability required for the pipe material.

[0004] Current technology reveals a lack of a dedicated integrated masterbatch solution for the specific applications of PE high-temperature resistant pipes and fittings. The core challenge lies in the fact that existing solutions primarily address single issues, such as dispersibility or chemical resistance, or are limited to specific application systems, such as coatings or certain engineering plastics. They fail to address the systemic design and innovation from multiple dimensions, including the inherent compatibility of the pigment-resin interface, the synergistic effect of functional components, and resistance to complex service environments. Therefore, the industry urgently needs an innovative technological approach that can simultaneously overcome the challenges of long-term stable pigment dispersion in the PE matrix, enhanced interfacial bonding, and synergistic improvement of macroscopic wear resistance, weather resistance, and heat resistance. This would allow for the development of dedicated masterbatch products with superior overall performance that meet the long-life requirements of high-end PE pipes and fittings. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention aims to provide a special color masterbatch for PE heat-resistant pipes and fittings that significantly improves wear resistance and weather resistance through synergistic compounding of functional materials and multi-scale reinforced structural design, as well as its preparation method.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: A color masterbatch for PE heat-resistant pipes and fittings comprises the following components in parts by weight: 40-65 parts carrier resin, 8-25 parts opacifier, 1.5-2.5 parts modified composite pigment, and 0-2 parts functional additives.

[0007] The carrier resin is composed of high-density polyethylene and linear low-density polyethylene in a mass ratio of 3-4:1-2.

[0008] The light-blocking agent is titanium dioxide.

[0009] The functional additive is at least one of antioxidants, light stabilizers, and high-efficiency dispersants.

[0010] Preferably, the functional additives are composed of antioxidants, light stabilizers, and high-efficiency dispersants in a mass ratio of 0.4-0.8:0.1-0.3:0.3-0.8.

[0011] The antioxidant is at least one of antioxidant 1010, antioxidant 168 and antioxidant 1076.

[0012] The light stabilizer is one or more of the following: (2,2,6,6-tetramethyl-4-hydroxypiperidine) benzoate, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, 2,6-di-tert-butyl-p-cresol, propyl gallate, 6-tert-butyl-m-cresol, 6-tert-butyl-2,4-dimethylphenol, and 2,6-di-tert-butyl-4-methylphenol.

[0013] The high-efficiency dispersant is at least one of zinc stearate, fatty acid amide, and polyethylene wax.

[0014] The preparation method of the modified composite pigment is as follows: S1. The functional material is added to anhydrous ethanol and ultrasonically treated to obtain a dispersion; the silane compound is added to an ethanol aqueous solution, the pH of the system is adjusted with ammonia, and then mixed with the dispersion, heated and stirred to obtain a modified coating solution. S2. Add the composite pigment to the modified coating solution prepared in step S1, and perform mechanical stirring under ultrasonic assistance. After centrifugation, drying, ball milling and sieving, the modified composite pigment is obtained.

[0015] Preferably, the modified composite pigment is prepared by the following method, in parts by weight: S1. Add 0.2-0.35 parts of functional material to 20-40 parts of anhydrous ethanol, and treat with ultrasound at 100-300W for 10-30 minutes to obtain a dispersion; then, add 0.1-0.2 parts of silane compound to 10-30 parts of 70-80wt% ethanol aqueous solution, adjust the pH of the system to 7.5-9 with 20-27wt% ammonia water, and then mix with the aforementioned dispersion; stir continuously at 50-70℃ for 1-3 hours to obtain a modified coating solution; S2. Add 2-3.5 parts of composite pigment to the modified coating solution prepared in step S1, and treat it for 1-3 hours under ultrasonic-assisted mechanical stirring at 100-300W. After centrifugation and vacuum drying at 40-60℃ for 5-20 hours, the product is ball-milled and passed through a 200-300 mesh sieve to obtain the modified composite pigment.

[0016] The composite pigment is composed of titanium yellow, ultramarine blue, iron oxide, and carbon black in a mass ratio of 1-1.5:0.5-1:0.05-0.1:0.03-0.1.

[0017] The functional material is at least one of titanium dioxide, nano zinc oxide, nano cerium dioxide, nano silicon dioxide, nano aluminum oxide, nano zirconium oxide, nano indium tin oxide, nano hydroxyapatite, and calcium sulfate whiskers.

[0018] Preferably, the functional material is composed of nano-hydroxyapatite and nano-cerium dioxide in a mass ratio of 4-6:1-3.

[0019] More preferably, the functional material is composed of nano-hydroxyapatite, nano-cerium dioxide and calcium sulfate whiskers in a mass ratio of 4-6:1-3:0.5-2.

[0020] The silane compound is at least one of methyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, tetramethoxysilane, octyltrimethoxysilane, 3-glycidyl etheroxypropyltrimethoxysilane, trifluoropropyltrimethoxysilane, and tridecafluorooctyltrimethoxysilane.

[0021] Preferably, the silane compound is a combination of methyltrimethoxysilane and tridecafluorooctyltrimethoxysilane in a mass ratio of 3-5:0.5-2.

[0022] The preparation method of the special color masterbatch for PE heat-resistant pipes and fittings is as follows: Modified composite pigments and high-efficiency dispersants are premixed in a high-speed mixer at room temperature for 5-10 minutes to prepare a uniform pigment concentrate. Next, a segmented hot-mixing kneading process is performed, where the carrier resin and opacifier are placed in a mixer and mixed at 80-95°C for 3-10 minutes. The material is then cooled to 50-60°C, and the aforementioned pigment concentrate, antioxidant, and light stabilizer are added. Mixing continues at 50-60°C for another 3-10 minutes to obtain a uniformly mixed material. Finally, melt extrusion granulation is performed: the resulting material... The material is melt-extruded through a parallel co-rotating twin-screw extruder. The extruder feed port temperature is controlled to be below 150℃, the temperatures of zones 1 to 9 of the extruder body are each independently 150-210℃, the die head and grinding head temperatures are 170-180℃, and the screw speed is 180-200 rpm. After being melted and plasticized, the material is filtered through a double-stage filter screen consisting of three layers of 60-100 mesh and two layers of 80-120 mesh. After being stretched, cooled by water, granulated, dehydrated, and screened, it is homogenized for 5-10 minutes to finally obtain the special color masterbatch.

[0023] The design concept of this invention follows a strategy of step-by-step optimization and functional synergy. First, a blend of high-density polyethylene and linear low-density polyethylene is selected as the carrier resin to balance the rigidity and toughness of the material, providing basic mechanical properties for the masterbatch. Then, addressing the core issues of pigment agglomeration and poor compatibility with the resin, a functional coating layer is designed to be constructed on the surface of the composite pigment. Through the hydrolytic condensation of silane compounds, the selected functional materials are firmly bonded to the pigment surface. This coating layer acts as a bridge, significantly enhancing the interfacial bonding between the pigment and the resin, and also acts as a barrier, physically isolating external mechanical wear and UV aging factors. Furthermore, for… Breaking through the performance limits of single-function materials, a compound synergistic design is adopted, combining nano-hydroxyapatite, which provides mechanical reinforcement, with nano-cerium dioxide, which provides UV shielding, to achieve a synergistic effect on wear resistance and weather resistance. Furthermore, micron-scale reinforcements such as calcium sulfate whiskers are introduced to form a multi-scale reinforcement network with nanomaterials, achieving another breakthrough in wear resistance. Finally, through precise segmented mixing, low-temperature kneading, and controllable twin-screw extrusion processes, the uniform dispersion of each component, sufficient interfacial reaction, and avoidance of high-temperature degradation are ensured, thereby ultimately producing a special masterbatch with high coloring power, excellent weather resistance, superior wear resistance, and good processing stability.

[0024] Compared with the prior art, the present invention has the following beneficial technical effects: 1) This invention significantly improves the dispersion stability and interfacial bonding of pigments in the resin matrix through a unique surface modification technology, thereby effectively improving the color uniformity and color brightness of the masterbatch.

[0025] 2) The color masterbatch prepared by this invention has excellent weather resistance and wear resistance, which can significantly delay the color fading and surface wear of products in harsh outdoor environments and greatly extend their service life.

[0026] 3) The preparation process of the present invention improves production efficiency and product quality stability by optimizing segmented processing and temperature control, while ensuring that the components are fully integrated and perform well. Detailed Implementation

[0027] Some material parameters and their sources: High-density polyethylene, grade: DMDA8920, manufacturer (origin): Dow Chemical, USA.

[0028] Linear low-density polyethylene, grade: LL 1201BS, brand: ExxonMobil.

[0029] Titanium dioxide, product specifications: 0.4µm, active ingredient content: ≥93%, crystal form: rutile, pH value: 7.9, density: 4.0g / cm³ 3 Brand: DuPont, USA.

[0030] Nano zinc oxide, average particle size: 50nm, purity: 99.9%, color: white.

[0031] Nano-cerium dioxide, average particle size: 50nm, purity: 99.9%, specific surface area (m²) 2 / g): 30, bulk density (g / cm³) 3 : 0.47, density (g / cm³) 3 ): 7.1, Crystal form: spherical, Color: white.

[0032] Nano-silica, particle size: 50nm, purity: 99.9%, crystal morphology: spherical.

[0033] Nano-alumina, crystal form: α phase, particle size (nm): 30nm, content (%): 99.99, specific surface area (m / g): 20-50.

[0034] Nano-zirconia, average particle size 50nm, purity (%): 99.9, crystal phase: tetragonal, color: white.

[0035] Nano-sized indium tin oxide, average particle size: 50nm, purity %: 99.9%, microstructure: spherical, color: light yellow.

[0036] Nano-hydroxyapatite, average particle size: 30nm, purity %: 99, color and appearance: white powder.

[0037] Calcium sulfate whiskers, appearance: white flocculent powder, Mohs hardness: 2-4, whiteness: ≥95%, chemical composition: CaSO4, purity: ≥98%, heat resistance: 1000℃, melting point: 1450℃, moisture: <1.5%, density: 2.69 g / cm³ 3Shape: needle-like fiber, diameter: 1-4μm, length: 10-300μm, aspect ratio: 40-80 (90%).

[0038] All other raw materials used in the embodiments and comparative examples of this invention are commercially available products.

[0039] Example 1 The preparation method of a special color masterbatch for PE heat-resistant pipes and fittings is as follows, in parts by weight: 2.13 parts of modified composite pigment and 0.5 parts of zinc stearate were premixed in a high-speed mixer at room temperature for 8 minutes to prepare a uniform pigment concentrate. Next, a segmented hot-mixing process was performed. 60 parts of a carrier resin composed of high-density polyethylene and linear low-density polyethylene in a mass ratio of 3.5:1.5 and 15 parts of titanium dioxide were placed in a mixer and mixed at 90°C for 6 minutes. The material was then cooled to 55°C, and the aforementioned pigment concentrate, along with 0.3 parts of antioxidant 1010, 0.3 parts of antioxidant 168, and 0.2 parts of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, were added. Mixing continued at 55°C. After mixing for 6 minutes, a uniformly mixed material is obtained. Finally, melt extrusion granulation is performed: the obtained material is melt-extruded through a parallel co-rotating twin-screw extruder. The extruder feed port temperature is controlled at 130℃, the temperatures of zones 1 to 9 of the extruder body are 150℃, 180℃, 180℃, 180℃, 180℃, 180℃, 175℃, 175℃, and the die head and grinding head temperature is 175℃. The screw speed is 190 rpm. After being melt-plasticized, the material is filtered through a double-stage filter screen with three layers of 80 mesh and two layers of 100 mesh. After being stretched, cooled by water, granulated, dehydrated, and screened, it is homogenized for 8 minutes to finally obtain the special color masterbatch.

[0040] The preparation method of the modified composite pigment is as follows, in parts by weight: S1. Add 0.28 parts of functional material to 30 parts of anhydrous ethanol and treat with ultrasound at 200W for 20 minutes to obtain a dispersion; then, add 0.15 parts of silane compound to 20 parts of 75wt% ethanol aqueous solution, adjust the pH of the system to 8 with 25wt% ammonia water, and then mix with the aforementioned dispersion; stir continuously at 60℃ for 2 hours to obtain a modified coating solution. S2. Add 2.13 parts of composite pigment to the modified coating solution prepared in step S1, and treat it for 2 hours under ultrasonic-assisted mechanical stirring at 250W. After centrifugation and vacuum drying at 50℃ for 12 hours, the product is ball-milled and passed through a 300-mesh sieve to obtain the modified composite pigment.

[0041] The composite pigment is composed of titanium yellow, ultramarine blue, iron oxide and carbon black in a mass ratio of 1.2:0.8:0.08:0.05.

[0042] The functional material is titanium dioxide.

[0043] The silane compound is composed of methyltrimethoxysilane and tridecafluorooctyltrimethoxysilane in a mass ratio of 4:1.

[0044] Example 2 The preparation method of a special color masterbatch for PE heat-resistant pipes and fittings is basically the same as that in Example 1, except that the functional material in the preparation method of the modified composite pigment is nano zinc oxide.

[0045] Example 3 The preparation method of a special color masterbatch for PE heat-resistant pipes and fittings is basically the same as that in Example 1, except that the functional material in the preparation method of the modified composite pigment is nano-cerium dioxide.

[0046] Example 4 The preparation method of a special color masterbatch for PE heat-resistant pipes and fittings is basically the same as that in Example 1, except that the functional material in the preparation method of the modified composite pigment is nano-silica.

[0047] Example 5 The preparation method of a special color masterbatch for PE heat-resistant pipes and fittings is basically the same as that in Example 1, except that the functional material in the preparation method of the modified composite pigment is nano-alumina.

[0048] Example 6 The preparation method of a special color masterbatch for PE heat-resistant pipes and fittings is basically the same as that in Example 1, except that the functional material in the preparation method of the modified composite pigment is nano-zirconia.

[0049] Example 7 The preparation method of a special color masterbatch for PE heat-resistant pipes and fittings is basically the same as that in Example 1, except that the functional material in the preparation method of the modified composite pigment is nano-indium tin oxide.

[0050] Example 8 The preparation method of a special color masterbatch for PE heat-resistant pipes and fittings is basically the same as that in Example 1, except that the functional material in the preparation method of the modified composite pigment is nano-hydroxyapatite.

[0051] Example 9 The preparation method of a special color masterbatch for PE heat-resistant pipes and fittings is basically the same as that in Example 1, except that the functional material in the preparation method of the modified composite pigment is composed of nano hydroxyapatite and nano cerium dioxide in a mass ratio of 5:2.

[0052] Example 10 The preparation method of a special color masterbatch for PE heat-resistant pipes and fittings is basically the same as that in Example 1, except that the functional material in the preparation method of the modified composite pigment is composed of nano-silica and nano-alumina in a mass ratio of 5:2.

[0053] Example 11 The preparation method of a special color masterbatch for PE heat-resistant pipes and fittings is basically the same as that in Example 1, except that the functional material in the preparation method of the modified composite pigment is composed of titanium dioxide and nano zinc oxide in a mass ratio of 5:2.

[0054] Example 12 The preparation method of a special color masterbatch for PE heat-resistant pipes and fittings is basically the same as that in Example 1, except that the functional material in the preparation method of the modified composite pigment is composed of nano hydroxyapatite, nano cerium dioxide and calcium sulfate whiskers in a mass ratio of 5:2:1.

[0055] Comparative Example 1 The preparation method of a special color masterbatch for PE heat-resistant pipes and fittings is basically the same as that in Example 1, except that the modified composite pigment is replaced with an equal amount of composite pigment.

[0056] The composite pigment is the same as in Example 1.

[0057] Test Example 1 Abrasion resistance test: Refer to the relevant methods in GB / T 1768-2006 "Determination of Abrasion Resistance of Paints and Varnishes".

[0058] The color masterbatches prepared in each embodiment and comparative example were mixed with PE base material at a fixed weight ratio of 9%, and injection molded into smooth plastic specimens with standard dimensions of 100mm × 100mm × 2mm using an injection molding machine at a melt temperature of 220℃. The specimen was fixed on a Taber abrasion tester, and a 1000g load was applied using a CS-10 grinding wheel. After rotating the specimen 1000 times, it was removed. The mass loss (mg) of the specimen before and after abrasion was accurately measured. The smaller the mass loss, the better the abrasion resistance.

[0059] The test results are shown in Table 1.

[0060] Table 1 Test Example 2 Weather resistance test: This indicator directly verifies the material's ability to retain color under long-term ultraviolet irradiation, and is key to proving the core function of cerium dioxide and its synergistic effect with the overall structure.

[0061] A smooth plastic sample was prepared according to the method in Test Example 1. The sample was then placed in a xenon lamp aging test chamber, and the irradiation intensity was set to 60 ± 2 W / m². 2 (In the 300nm-400nm ultraviolet band), blackboard temperature: 63±3℃, chamber temperature: 45±3℃, relative humidity: 50±5%, spraying cycle: spraying for 18 minutes after every 102 minutes of light exposure, total test duration: 500 hours.

[0062] After the test, remove the color plates. Use a colorimeter to measure the color change of the color plates before and after aging, expressed as the total color difference ΔE. The smaller the ΔE value, the better the color stability and the better the weather resistance.

[0063] The relevant test data are summarized in Table 2.

[0064] Table 2 The possible mechanism by which the modified composite pigments of this invention improve performance lies in constructing a robust functional material coating layer on the pigment surface using silane compounds. This coating layer improves the compatibility and interfacial bonding between the pigment and the PE resin matrix, and physically isolates the internal pigment core from direct attacks by external factors such as mechanical friction and UV aging. This results in the superior performance of Examples 1-8 compared to the unmodified Comparative Example 1. Among single functional materials, nano-hydroxyapatite exhibits the best wear resistance due to its unique nanowire structure forming a dense network reinforcement layer; while nano-cerium dioxide, as a UV absorber, delays the photo-oxidative aging of the matrix, exhibiting the best weather resistance. When nano-hydroxyapatite and nano-cerium dioxide are combined, they produce a significant synergistic effect. The physical reinforcement provided by hydroxyapatite and the chemical protection provided by cerium dioxide complement each other, and the dense network formed by the former promotes the uniform distribution of cerium dioxide, while the latter ensures the durability of the reinforcement network, achieving a leapfrog improvement in overall performance. In contrast, silicon dioxide and alumina have overlapping functions, and titanium dioxide and zinc oxide lack sufficient synergy. Further, calcium sulfate whiskers were introduced to form a ternary system, constructing a multi-scale synergistic reinforcement network. Hydroxyapatite nanowires form the basic framework, while micron-sized calcium sulfate whiskers intertwine with it as a rigid reinforcement, much like a composite structure of steel bars and fine mesh. This achieves another breakthrough in wear resistance on the basis of the long-term stability guaranteed by cerium dioxide.

Claims

1. A masterbatch for PE temperature resistant pipe fittings, characterized in that, Comprise the following components by weight parts: Carrier resin 40-65 parts, light shielding agent 8-25 parts, modified composite pigment 1.5-2.5 parts, functional auxiliary agent 0-2 parts; The preparation method of the modified composite pigment is as follows: S1, the functional material is added to anhydrous ethanol, and is treated by ultrasonic to obtain a dispersion liquid; the silane compound is added to an ethanol aqueous solution, the pH of the system is adjusted by using ammonia water, and then the dispersion liquid is mixed and stirred to prepare a modified coating solution; S2, the composite pigment is added to the modified coating solution prepared in step S1, and is treated by mechanical stirring under ultrasonic assistance; the reaction product is centrifuged, dried, ball milled and sieved to obtain the modified composite pigment; The functional material is at least one of titanium white, nano zinc oxide, nano cerium dioxide, nano silicon dioxide, nano aluminum oxide, nano zirconium oxide, nano indium tin oxide, nano hydroxyapatite and calcium sulfate whisker.

2. The PE temperature resistant pipe fitting special masterbatch of claim 1, wherein, The carrier resin is a combination of high-density polyethylene and linear low-density polyethylene in a mass ratio of 3-4:1-2; the light shielding agent is titanium white; the functional auxiliary agent is at least one of an antioxidant, a light stabilizer and a high-efficiency dispersant.

3. The PE temperature resistant pipe fitting special masterbatch of claim 1 or 2, characterized in that, The functional auxiliary agent is composed of an antioxidant, a light stabilizer and a high-efficiency dispersant in a mass ratio of 0.4-0.8:0.1-0.3:0.3-0.8; the antioxidant is at least one of antioxidant 1010, antioxidant 168 and antioxidant 1076; the light stabilizer is one or more of benzoic acid (2,2,6,6-tetramethyl-4-hydroxypiperidine) ester, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, 2,6-di-tert-butyl-p-cresol, propyl gallate, 6-tert-butyl-m-cresol, 6-tert-butyl-2,4-dimethylphenol and 2,6-di-tert-butyl-4-methylphenol; and the high-efficiency dispersant is at least one of zinc stearate, fatty acid amide and polyethylene wax.

4. The PE temperature resistant pipe fittings special masterbatch of claim 1, wherein, The preparation method of the modified composite pigment is as follows, in terms of weight parts: S1, 0.2-0.35 parts of the functional material is added to 20-40 parts of anhydrous ethanol, and is treated by 100-300 W ultrasonic for 10-30 minutes to obtain a dispersion liquid; Then, 0.1-0.2 parts of the silane compound is added to 10-30 parts of 70-80 wt% ethanol aqueous solution, the pH of the system is adjusted to 7.5-9 by using 20-27 wt% ammonia water, and then the dispersion liquid is mixed; the mixture is continuously stirred at 50-70℃ for 1-3 hours to prepare a modified coating solution; S2, 2-3.5 parts of the composite pigment is added to the modified coating solution prepared in step S1, and is treated by mechanical stirring under 100-300 W ultrasonic assistance for 1-3 hours; the product is centrifuged, vacuum dried at 40-60℃ for 5-20 hours, and then ball milled and sieved through a 200-300 mesh sieve to obtain the modified composite pigment.

5. The PE temperature resistant pipe fittings special masterbatch of claim 1, wherein, The composite pigment is composed of titanium yellow, ultramarine blue, iron oxide, carbon black in a mass ratio of 1-1.5:0.5-1:0.05-0.1:0.03-0.

1.

6. The PE temperature resistant pipe fittings special masterbatch of claim 1, wherein, The functional material is a combination of nano hydroxyapatite and nano cerium dioxide in a mass ratio of 4-6:1-3.

7. The PE temperature resistant pipe fittings special masterbatch of claim 1, wherein, The functional material is a combination of nano-hydroxyapatite, nano-cerium dioxide and calcium sulfate whisker in a mass ratio of 4-6:1-3:0.5-2.

8. The PE temperature resistant pipe fittings special masterbatch of claim 1, wherein, The silane compound is at least one of methyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, ethyl orthosilicate, tetramethoxysilane, octyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, trifluoropropyltrimethoxysilane and tridecafluorooctyltrimethoxysilane.

9. The PE temperature resistant pipe fittings masterbatch for special color concentrate of claim 1, wherein, The silane compound is a combination of methyltrimethoxysilane and tridecafluorooctyltrimethoxysilane in a mass ratio of 3-5:0.5-2.

10. A process for the preparation of the PE temperature resistant pipe and fitting special masterbatch according to any one of claims 1 to 9, characterized in that, The method is as follows: The modified composite pigment and the high-efficiency dispersant are premixed in a high-speed mixer at room temperature for 5-10 minutes to prepare a uniform pigment concentrate package; then, a stepwise thermal mixing and kneading is performed, the carrier resin and the light shielding agent are placed in the mixer and mixed at a temperature of 80-95 DEG C for 3-10 minutes, then the material is cooled to 50-60 DEG C, the pigment concentrate package, the antioxidant and the light stabilizer are added, and the mixture is continuously mixed at 50-60 DEG C for 3-10 minutes to obtain a uniformly mixed material; finally, melt extrusion granulation is performed, the obtained material is melt extruded through a parallel co-rotating twin-screw extruder, the temperature of the discharge port of the extruder is controlled to be below 150 DEG C, the temperature of the body of the extruder is independently controlled to be 150-210 DEG C, the temperature of the head and the grinding head is 170-180 DEG C, the screw rotation speed is 180-200 rpm, the material is melt plasticized and then filtered through double-stage filter screens of 60-100 mesh and 80-120 mesh in sequence, then the material is drawn, water-cooled, cut, dehydrated, screened and homogenized for 5-10 minutes, and finally the special color masterbatch is prepared.

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