High-weather-resistance and high-dispersion PPR (polypropylene random copolymer) pipeline color master batch and preparation method thereof

Abstract

The invention relates to the technical field of advanced petrochemical and chemical new materials, in particular to a high-weather-resistance and high-dispersion PPR (polypropylene random copolymer) pipeline color master batch and a preparation method thereof, the high-weather-resistance and high-dispersion PPR pipeline color master batch comprises the following components: a composite functional carrier system, a dual modified pigment, a weather-resistant synergistic aid and a processing aid; the composite functional carrier system is prepared from the following components: compatible carrier resin, an interface regulator, a dynamic cross-linking agent and the balance of vinyl elastomer; the vinyl elastomer is an ethylene-octylene copolymer; the compatible carrier resin is a compound of homo-polypropylene and maleic anhydride grafted polypropylene; through component compounding and optimization of a modification process and processing parameters, the problems of poor dispersion, weak weather resistance and insufficient compatibility of the existing color master batch are thoroughly solved, so that a PPR pipeline not only meets the basic requirement of sanitary water supply, but also can adapt to an outdoor severe environment, the application range of the PPR pipeline in scenes such as municipal engineering and building outer wall water supply is expanded, and the application prospect is wide. And the practical value is remarkable.

Description

Technical Field

[0001] This invention relates to the field of advanced petrochemical new materials technology, specifically to a high weather-resistant and highly dispersible PPR pipe color masterbatch and its preparation method. Background Technology

[0002] PPR pipes, with their advantages of being hygienic, non-toxic, corrosion-resistant, and having low fluid resistance, are widely used in building hot and cold water supply, municipal water supply and drainage, and other fields. Masterbatch, as a core auxiliary material that determines the appearance and performance of PPR pipes, directly affects the pipe's service life and application effectiveness. In actual use, PPR pipes often face outdoor environments exposed to sun and rain, which places stringent requirements on the dispersibility, weather resistance, and compatibility of the masterbatch with the PPR substrate.

[0003] However, existing color masterbatches for PPR pipes still have many problems that urgently need to be solved: Traditional color masterbatches mostly use polypropylene as a single carrier resin, which has poor compatibility with polar inorganic pigments, elastomers, and other components. This leads to pigment agglomeration during processing, causing not only color differences and spots on the pipe surface but also stress concentration, reducing the tensile and impact performance of the pipe. The pigments used are relatively conventional, making it difficult to achieve good dispersibility and weather resistance simultaneously. This makes the pipes susceptible to ultraviolet corrosion when used outdoors, resulting in discoloration and chalking. Weather-resistant additives are mostly conventional components, unable to form comprehensive anti-aging protection, leading to rapid degradation of the pipe's mechanical properties. The conventional processing parameters of some color masterbatches easily cause uneven mixing or insufficient melting, further exacerbating the problems of poor dispersibility and unstable performance. These defects make it difficult for existing color masterbatches to meet the needs of PPR pipes for long-term outdoor use, limiting their application in a wider range of scenarios. Summary of the Invention

[0004] The purpose of this invention is to provide a highly weather-resistant and highly dispersible PPR pipe color masterbatch and its preparation method.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A highly weather-resistant and highly dispersible PPR pipe color masterbatch, by weight, comprises the following components: 45-55 parts of a composite functional carrier system, 22-28 parts of dual-modified pigments, 6-8 parts of weather-resistant synergistic additives, and 2-4 parts of processing aids; The composite functional carrier system is composed of the following components by mass percentage: 63-67% compatibility carrier resin, 6-8% interface modifier, 0.8-1.5% dynamic crosslinking agent, and the balance being vinyl elastomer; The vinyl elastomer is an ethylene-octene copolymer with a melt index (190℃ / 2.16kg) of 2-4 g / 10min; The compatibility carrier resin is a compound of homopolymer polypropylene and maleic anhydride-grafted polypropylene with a mass ratio of 4:1. The dual-modified pigment is an inorganic pigment that has been modified by plasma grafting and then coated by in-situ polymerization. The mixed monomers of the in-situ polymerization are composed of methyl methacrylate, hydroxyethyl acrylate and γ-glycidoxypropyltrimethoxysilane in a mass ratio of 18:9:3. The dynamic crosslinking agent is zinc dithiocarbamate.

[0006] As a further technical solution, the preparation method of the composite functional carrier system includes the following steps: S1 mixes vinyl elastomer, homopolymer polypropylene, and maleic anhydride-grafted polypropylene in a certain proportion, adds them to a high-speed mixer, and mixes them at 85-90℃ and 900-1000rpm for 12-15 minutes to obtain a premix. S2 adds the premixed material to a twin-screw extruder with a length-to-diameter ratio of 40:1 for melt blending and extrusion. The temperatures of each section of the extruder are: Zone 1 145-150℃, Zone 2 165-170℃, Zone 3 180-185℃, Zone 4 185-190℃, and the die head 180-185℃. The screw speed is 350-400 rpm. After extrusion, the material is sprayed with water for cooling and pelletized to obtain composite carrier particles. S3 mixes the composite carrier particles with an interface modifier and a dynamic crosslinking agent, and stirs them at 65-70℃ and 550-600rpm for 6-8 minutes to obtain a composite functional carrier system.

[0007] As a further technical solution, the preparation method of the dual-modified pigment includes the following steps: a. Plasma grafting modification: Inorganic pigments are placed in a plasma processor with a vacuum of 15-20 Pa. A mixture of argon and acrylic acid with a volume ratio of 10:1 is introduced, with a discharge power of 120-150 W and a processing time of 18-20 min to obtain grafted modified pigments. b. In-situ polymerization coating modification: The grafted modified pigment is dispersed in deionized water and ultrasonically dispersed. Then, an emulsifier and an initiator are added, the temperature is raised to 75-80℃, and mixed monomers are added dropwise over a period of 2.5-3 hours. The reaction is maintained at this temperature for 4.5-5 hours. After the reaction is completed, the pigment is centrifuged, washed, and dried at 80℃ for 4 hours to obtain the double-modified pigment.

[0008] As a further technical solution, the initiator is ammonium persulfate, and the amount used is 1.0% of the mass of the mixed monomers; the emulsifier is sodium dodecyl sulfate, and the amount used is 3.5% of the mass of the mixed monomers.

[0009] As a further technical solution, the ultrasonic dispersion power is 300-400W and the dispersion time is 30-40min.

[0010] As a further technical solution, the inorganic pigment is one or more of titanium dioxide, carbon black, and iron oxide red.

[0011] As a further technical solution, the interface modifier is γ-aminopropyltriethoxysilane.

[0012] As a further technical solution, the weather-resistant synergist is a compound of UV absorber UV-531 and hindered amine light stabilizer HALS944, with a mass ratio of 1.5:1, and the mass ratio of the weather-resistant synergist to the dual-modified pigment is 1:2.5.

[0013] As a further technical solution, the processing aid includes an antioxidant and a lubricant. The antioxidant is a compound of 1010 and 168 in a mass ratio of 1:1, and the lubricant is calcium stearate. The mass ratio of the antioxidant to the lubricant is 2.5:1.

[0014] A method for preparing highly weather-resistant and highly dispersible PPR pipe color masterbatch includes the following steps: (1) Weigh each component according to the mass ratio, add it to a high-speed mixer, mix at 95-100℃ and 1100-1200rpm for 18-20min, and control the moisture content of the mixture to ≤0.3% to obtain the mixture. (2) Add the mixture to a twin-screw extruder with a length-to-diameter ratio of 40:1 and melt-blend and extrude. The temperatures of each section of the extruder are: Zone 1 155-160℃, Zone 2 175-180℃, Zone 3 190-195℃, Zone 4 195-200℃, and the die head 190-195℃. The screw speed is 380-420 rpm. (3) The extruded material is cooled with water, pelletized, and dried at 80℃ for 2.5-3 hours to obtain highly weather-resistant and highly dispersible PPR pipe color masterbatch; The color masterbatch is mixed with the PPR substrate at a mass ratio of 1:50-60.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. The optimized combination and microscopic effects of the components in this invention lay the foundation for the performance of the masterbatch. In the composite functional carrier system, the homopolymer polypropylene and maleic anhydride-grafted polypropylene are compounded in a 4:1 ratio to form a compatible carrier resin. The polar groups of maleic anhydride act as a bridge, effectively connecting the non-polar PPR substrate with the polar pigments and elastomers, significantly reducing interfacial tension and solving the problem of insufficient compatibility in traditional single carriers. The interface modifier γ-aminopropyltriethoxysilane further reduces the repulsive forces between components, promoting uniform fusion of the phases. The dynamic crosslinking agent zinc dithiocarbamate can construct a dynamic crosslinking network. During processing, network reconstruction improves melt flow, and during use, the network maintains structural strength, achieving a balance between rigidity and toughness. The ethylene-octene copolymer specifically enhances the system's toughness, preventing cracking of pipes due to brittleness. The dual-modified pigments undergo plasma treatment to form active groups on their surface, enhancing their adhesion to subsequent coating layers. Then, through in-situ polymerization and coating with a specific ratio of mixed monomers, a protective layer with both compatibility and weather resistance is formed, fundamentally improving the pigment agglomeration problem. The weather-resistant synergist UV-531 and HALS944 are compounded in a 1.5:1 ratio to achieve complementary functions of ultraviolet absorption and free radical capture, respectively. The compounding of antioxidants 1010 and 168 in the processing aids inhibits thermo-oxidative aging, and calcium stearate optimizes processing fluidity. The synergistic effect of each component improves the overall performance.

[0016] 2. In the technical solution of this invention, the two-step treatment of the dual-modified pigment forms a synergy: plasma surface activation makes the in-situ polymerized coating layer more firmly bonded, preventing it from falling off during use and significantly enhancing weather resistance; the components of the composite functional carrier system work synergistically, with the compatibility carrier solving the bonding problem, the interface regulator solving the dispersion problem, the dynamic crosslinking agent solving the mechanical balance problem, and the ethylene-octene copolymer solving the toughness problem, together providing a stable dispersion environment for the pigment, so that after the masterbatch is mixed with the PPR substrate, the overall performance of the PPR pipe can be further improved. The weather-resistant additive and the dual-modified pigment are matched in a ratio of 1:2.5, so that the protective effect precisely covers the pigment surface, avoiding waste of additives or blind spots in protection; the processing technology and component characteristics are matched, the gradient mixing and extrusion temperature matches the melting characteristics of each component, ensuring sufficient melting without damaging the structure, and ultrasonic dispersion provides uniform pretreatment for pigment coating. Each process step and component function work together to further amplify the synergistic effect.

[0017] 3. This invention, through the optimization of component compounding, modification process and processing parameters, completely solves the problems of poor dispersion, weak weather resistance and insufficient compatibility of existing color masterbatches, so that PPR pipes can not only meet the basic requirements of sanitary water supply, but also adapt to harsh outdoor environments, expanding its application scope in municipal engineering, building exterior wall water supply and other scenarios, and has significant practical value. Attached Figure Description

[0018] Figure 1 The following are statistical charts of impact intensity for both the example and comparative examples. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] This invention provides a highly weather-resistant and highly dispersible PPR pipe masterbatch. Through a specific composite functional carrier system, dual-modified pigments, weather-resistant synergistic agents, and processing aids, and a specific formulation and preparation process, the masterbatch achieves excellent weather resistance and dispersibility in PPR pipes, while ensuring processing stability and mechanical property compatibility.

[0021] I. Component description includes: (I) Composite functional carrier system: The composite functional carrier system comprises 45-55 parts by weight and consists of a compatibility carrier resin, an interface modifier, a dynamic crosslinking agent, and a vinyl elastomer. The mass percentages of each component are as follows: 63-67% compatibility carrier resin, 6-8% interface modifier, 0.8-1.5% dynamic crosslinking agent, and the balance being vinyl elastomer.

[0022] The vinyl elastomer is an ethylene-octene copolymer with a melt index (test conditions 190℃ / 2.16kg) of 2-4g / 10min, which can improve the toughness and processing fluidity of the system.

[0023] The compatibility carrier resin is a compound of homopolymer polypropylene and maleic anhydride-grafted polypropylene in a mass ratio of 4:1, which can improve the compatibility between the carrier and pigments and PPR substrates.

[0024] The interface modifier is γ-aminopropyltriethoxysilane, which can reduce the interfacial tension between components and promote uniform dispersion.

[0025] The dynamic crosslinking agent is zinc dithiocarbamate, which can construct a dynamic crosslinking network and balance the rigidity and toughness of the system.

[0026] (ii) Dually modified pigments: The dual-modified pigment accounts for 22-28 parts by weight. It is an inorganic pigment that has been modified by plasma grafting and then modified by in-situ polymerization coating. The inorganic pigment can be one or more of titanium dioxide, carbon black, and iron oxide red.

[0027] Plasma grafting modification: using a mixture of argon and acrylic acid (volume ratio 10:1) as a medium, pigment surface grafting is achieved under specific process conditions.

[0028] In-situ polymerization coating modification: The mixed monomers consist of methyl methacrylate, hydroxyethyl acrylate and γ-glycidoxypropyltrimethoxysilane in a mass ratio of 18:9:3; the initiator is ammonium persulfate, and the amount used is 1.0% of the mass of the mixed monomers; the emulsifier is sodium dodecyl sulfate, and the amount used is 3.5% of the mass of the mixed monomers.

[0029] (III) Weather-resistant synergists: The weather-resistant synergist accounts for 6-8 parts by weight and is a compound of UV absorber UV-531 and hindered amine light stabilizer HALS944 with a mass ratio of 1.5:1. The mass ratio of the weather-resistant synergist to the dual-modified pigment is 1:2.5, which can synergistically improve the UV aging resistance of the masterbatch.

[0030] (iv) Processing aids: The processing aids comprise 2-4 parts by weight, including antioxidants and lubricants. The antioxidant is a compound of 1010 and 168 in a mass ratio of 1:1, and the lubricant is calcium stearate. The mass ratio of antioxidant to lubricant is 2.5:1, which can improve thermal stability and mold release properties during processing.

[0031] II. Detailed explanation of the preparation method: (I) Preparation of composite functional carrier systems: Weigh out the vinyl elastomer, homopolymer polypropylene, and maleic anhydride-grafted polypropylene in proportion, add them to a high-speed mixer, and mix for 12-15 minutes at 85-90℃ and 900-1000 rpm to obtain a premix.

[0032] The premixed material is added to a twin-screw extruder with a length-to-diameter ratio of 40:1 and melt-blended and extruded. The temperatures of each section of the extruder are set as follows: Zone 1 145-150℃, Zone 2 165-170℃, Zone 3 180-185℃, Zone 4 185-190℃, and Die Head 180-185℃. The screw speed is 350-400 rpm. After extrusion, the material is sprayed with water for cooling and then pelletized to obtain composite carrier particles.

[0033] Weigh the composite carrier particles, interface modifier, and dynamic crosslinking agent according to the proportion, add them to a high-speed mixer, and stir for 6-8 minutes at 65-70℃ and 550-600 rpm to obtain the composite functional carrier system.

[0034] (II) Preparation of dual-modified pigments: Plasma grafting modification: Inorganic pigments are placed in a plasma processor, the vacuum is adjusted to 15-20 Pa, a mixture of argon and acrylic acid gas with a volume ratio of 10:1 is introduced, the discharge power is set to 120-150 W, and the processing time is 18-20 min to obtain grafted modified pigments.

[0035] In-situ polymerization coating modification: The grafted modified pigment is dispersed in deionized water and ultrasonically dispersed at 300-400W for 30-40 minutes. Emulsifier and initiator are added, the temperature is raised to 75-80℃, and mixed monomers are added dropwise. The dropwise addition time is controlled at 2.5-3 hours. After the dropwise addition is completed, the reaction is kept at the temperature for 4.5-5 hours. After the reaction is completed, the pigment is centrifuged, washed, and dried at 80℃ for 4 hours to obtain the double-modified pigment.

[0036] (III) Preparation of PPR pipe color masterbatch: Weigh out the composite functional carrier system, dual modified pigment, weather-resistant synergist, and processing aid by weight, add them to a high-speed mixer, and mix for 18-20 minutes at 95-100℃ and 1100-1200 rpm. Control the moisture content of the mixture to ≤0.3% to obtain the mixture.

[0037] The mixture is added to a twin-screw extruder with a length-to-diameter ratio of 40:1 and melt-blended and extruded. The temperatures of each section of the extruder are set as follows: Zone 1 155-160℃, Zone 2 175-180℃, Zone 3 190-195℃, Zone 4 195-200℃, and Die Head 190-195℃. The screw speed is 380-420 rpm.

[0038] The extruded material is cooled with water, pelletized, and dried at 80℃ for 2.5-3 hours to obtain a PPR pipe color masterbatch with high weather resistance and high dispersion; the color masterbatch is mixed with PPR base material at a mass ratio of 1:50-60.

[0039] The following are specific examples: Example 1: Preparation of a composite functional carrier system: Weigh out the following components by weight percentage: 63% compatibility carrier resin (homogeneous polypropylene and maleic anhydride grafted polypropylene in a mass ratio of 4:1), 6% interface modifier (γ-aminopropyltriethoxysilane), 0.8% dynamic crosslinking agent (zinc dithiocarbamate), and 30.2% vinyl elastomer (ethylene-octene copolymer, melt index 2 g / 10 min).

[0040] Take vinyl elastomer, homopolymer polypropylene, and maleic anhydride-grafted polypropylene, add them to a high-speed mixer, and mix for 12 minutes at 85°C and 900 rpm to obtain a premix.

[0041] The premixed material was added to a twin-screw extruder with a length-to-diameter ratio of 40:1. The temperatures of each section of the extruder were: 145℃ in zone 1, 165℃ in zone 2, 180℃ in zone 3, 185℃ in zone 4, and 180℃ at the die head. The screw speed was 350 rpm. After extrusion, the material was sprayed with water for cooling and then pelletized to obtain composite carrier particles.

[0042] The composite carrier particles were mixed with an interface modifier and a dynamic crosslinking agent, and stirred at 65°C and 550 rpm for 6 minutes to obtain a composite functional carrier system.

[0043] Preparation of dual-modified pigments: Titanium dioxide was used as an inorganic pigment and placed in a plasma treatment instrument with a vacuum of 15 Pa. A mixture of argon and acrylic acid with a volume ratio of 10:1 was introduced, and the discharge power was 120 W. The treatment lasted for 18 min to obtain the grafted modified pigment.

[0044] The grafted modified pigment was dispersed in deionized water and ultrasonically dispersed at 300W for 30 min. Sodium dodecyl sulfate (3.5% of the mixed monomer mass) and ammonium persulfate (1.0% of the mixed monomer mass) were added. The temperature was raised to 75℃, and the mixed monomer (methyl methacrylate: hydroxyethyl acrylate: γ-glycidoxypropyltrimethoxysilane = 18:9:3) was added dropwise over 2.5 h. The reaction was maintained at this temperature for 4.5 h. After centrifugation and washing, the mixture was dried at 80℃ for 4 h to obtain the dual-modified pigment.

[0045] Preparation of color masterbatch: Weigh out 45 parts by weight of the composite functional carrier system, 22 parts by weight of the dual modified pigment, 6 parts by weight of the weather-resistant synergist (UV-531:HALS944=1.5:1), and 2 parts by weight of the processing aid (antioxidant 1010:antioxidant 168:calcium stearate=2.5:2.5:2).

[0046] Add to a high-speed mixer and mix at 95°C and 1100 rpm for 18 minutes, controlling the moisture content to ≤0.3%, to obtain a mixture.

[0047] The mixture was fed into a twin-screw extruder with a length-to-diameter ratio of 40:1. The temperatures of each section of the extruder were: Zone 1 155℃, Zone 2 175℃, Zone 3 190℃, Zone 4 195℃, and Die Head 190℃. The screw speed was 380 rpm.

[0048] The extruded material is water-cooled, pelletized, and dried at 80°C for 2.5 hours to obtain color masterbatch; the color masterbatch is mixed with PPR substrate at a mass ratio of 1:50 for use.

[0049] Example 2: Preparation of composite functional carrier system: Weigh out the following components by weight percentage: 65% compatibility carrier resin (homogeneous polypropylene to maleic anhydride grafted polypropylene mass ratio 4:1), 7% interface modifier (γ-aminopropyltriethoxysilane), 1.2% dynamic crosslinking agent (zinc dithiocarbamate), and 26.8% vinyl elastomer (ethylene-octene copolymer, melt index 3 g / 10 min).

[0050] Take vinyl elastomer, homopolymer polypropylene, and maleic anhydride-grafted polypropylene, add them to a high-speed mixer, and mix for 13 minutes at 88°C and 950 rpm to obtain a premix.

[0051] The premixed material was added to a twin-screw extruder with a length-to-diameter ratio of 40:1. The temperatures of each section of the extruder were: 148℃ in zone 1, 168℃ in zone 2, 182℃ in zone 3, 188℃ in zone 4, and 183℃ at the die head. The screw speed was 380 rpm. After extrusion, the material was sprayed with water for cooling and then pelletized to obtain composite carrier particles.

[0052] The composite carrier particles were mixed with an interface modifier and a dynamic crosslinking agent, and stirred at 68°C and 580 rpm for 7 min to obtain a composite functional carrier system.

[0053] Preparation of dual-modified pigments: Carbon black was used as an inorganic pigment and placed in a plasma treatment instrument with a vacuum of 18 Pa. A mixture of argon and acrylic acid with a volume ratio of 10:1 was introduced, and the discharge power was 135 W. The treatment lasted for 19 min to obtain the grafted modified pigment.

[0054] The grafted modified pigment was dispersed in deionized water and ultrasonically dispersed at 350W for 35 min. Sodium dodecyl sulfate (3.5% of the mixed monomer mass) and ammonium persulfate (1.0% of the mixed monomer mass) were added. The temperature was raised to 78℃, and the mixed monomer (methyl methacrylate: hydroxyethyl acrylate: γ-glycidoxypropyltrimethoxysilane = 18:9:3) was added dropwise over 2.8 h. The reaction was maintained at this temperature for 4.8 h. After centrifugation and washing, the mixture was dried at 80℃ for 4 h to obtain the dual-modified pigment.

[0055] Preparation of color masterbatch: Weigh out 50 parts by weight of the composite functional carrier system, 25 parts of the dual modified pigment, 7 parts of the weather-resistant synergist (UV-531:HALS944=1.5:1), and 3 parts of the processing aid (antioxidant 1010:antioxidant 168:calcium stearate=2.5:2.5:2).

[0056] Add to a high-speed mixer and mix at 98°C and 1150 rpm for 19 minutes, controlling the moisture content to ≤0.3%, to obtain a mixture.

[0057] The mixture was fed into a twin-screw extruder with a length-to-diameter ratio of 40:1. The temperatures of each section of the extruder were: Zone 1 158℃, Zone 2 178℃, Zone 3 192℃, Zone 4 198℃, and Die Head 193℃. The screw speed was 400 rpm.

[0058] The extruded material is water-cooled, pelletized, and dried at 80°C for 2.8 hours to obtain color masterbatch; the color masterbatch is mixed with PPR substrate at a mass ratio of 1:55 for use.

[0059] Example 3: Preparation of composite functional carrier system: Weigh out the following components by weight percentage: 67% compatibility carrier resin (homogeneous polypropylene and maleic anhydride grafted polypropylene in a mass ratio of 4:1), 8% interface modifier (γ-aminopropyltriethoxysilane), 1.5% dynamic crosslinking agent (zinc dithiocarbamate), and 23.5% vinyl elastomer (ethylene-octene copolymer, melt index 4 g / 10 min).

[0060] Take vinyl elastomer, homopolymer polypropylene, and maleic anhydride-grafted polypropylene, add them to a high-speed mixer, and mix for 15 minutes at 90°C and 1000 rpm to obtain a premix.

[0061] The premixed material was added to a twin-screw extruder with a length-to-diameter ratio of 40:1. The temperatures of each section of the extruder were: 150℃ in zone 1, 170℃ in zone 2, 185℃ in zone 3, 190℃ in zone 4, and 185℃ at the die head. The screw speed was 400 rpm. After extrusion, the material was sprayed with water for cooling and then pelletized to obtain composite carrier particles.

[0062] The composite carrier particles were mixed with an interface modifier and a dynamic crosslinking agent, and stirred at 70°C and 600 rpm for 8 minutes to obtain a composite functional carrier system.

[0063] Preparation of dual-modified pigments: Iron oxide red was used as an inorganic pigment and placed in a plasma treatment instrument with a vacuum of 20 Pa. A mixture of argon and acrylic acid with a volume ratio of 10:1 was introduced, and the discharge power was 150 W. The treatment lasted for 20 min to obtain the grafted modified pigment.

[0064] The grafted modified pigment was dispersed in deionized water and ultrasonically dispersed at 400W for 40 min. Sodium dodecyl sulfate (3.5% of the mixed monomer mass) and ammonium persulfate (1.0% of the mixed monomer mass) were added. The temperature was raised to 80℃, and the mixed monomer (methyl methacrylate: hydroxyethyl acrylate: γ-glycidoxypropyltrimethoxysilane = 18:9:3) was added dropwise over 3 h. The reaction was kept at this temperature for 5 h. After centrifugation and washing, the mixture was dried at 80℃ for 4 h to obtain the dual-modified pigment.

[0065] Preparation of color masterbatch: Weigh out 55 parts by weight of the composite functional carrier system, 28 parts by weight of the dual modified pigment, 8 parts by weight of the weather-resistant synergist (UV-531:HALS944=1.5:1), and 4 parts by weight of the processing aid (antioxidant 1010:antioxidant 168:calcium stearate=2.5:2.5:2).

[0066] Add to a high-speed mixer and mix at 100℃ and 1200rpm for 20 minutes, controlling the moisture content to ≤0.3%, to obtain a mixture.

[0067] The mixture was fed into a twin-screw extruder with a length-to-diameter ratio of 40:1. The temperatures of each section of the extruder were as follows: Zone 1 160℃, Zone 2 180℃, Zone 3 195℃, Zone 4 200℃, and Die Head 195℃. The screw speed was 420 rpm.

[0068] The extruded material is water-cooled, pelletized, and dried at 80°C for 3 hours to obtain color masterbatch; the color masterbatch is mixed with PPR substrate at a mass ratio of 1:60 for use.

[0069] test: Experiment 1: Verification experiment on the synergistic effect of composite functional carrier system; Using Example 1 as the baseline, three comparative examples were designed, each with a different key component of the composite functional carrier system, while maintaining the same preparation conditions as Example 1. The color masterbatch and PPR substrate were mixed at a ratio of 1:50 and injection molded into standard specimens. Tensile strength was tested according to GB / T 1040.2-2022, and cantilever beam impact strength was tested according to GB / T1843-2008. The results are as follows: Table 1 As shown in Table 1, Example 1 exhibits the best mechanical properties, indicating a synergistic effect among the components of the composite functional carrier system. Comparative Example 1 lacks an interface modifier, resulting in excessive interfacial tension between the carrier and the pigment / substrate, leading to pigment agglomeration and a decrease in mechanical properties. Comparative Example 2 lacks a dynamic crosslinking agent, failing to form a dynamic crosslinking network, resulting in insufficient system toughness and a significant decrease in impact strength. Comparative Example 3 uses a single homopolymer polypropylene as the compatibility carrier resin, lacking the polar groups of maleic anhydride-grafted polypropylene, leading to poor compatibility and the worst tensile and impact strength.

[0070] Experiment 2: Verification test of the modification effect of dual-modified pigments; Using Example 1 as the baseline, three comparative groups were designed, changing the pigment modification method while maintaining the same preparation conditions as Example 1. Each group of masterbatch was mixed with PPR substrate at a ratio of 1:50 and injection molded into standard specimens. Tinting strength was tested according to GB / T13451.2-1992 (with Example 1 as 100%), and the specimens were aged under a xenon arc lamp for 1000 hours according to GB / T16422.2-2014. The color difference ΔE was tested (a smaller ΔE indicates better weather resistance). The results are as follows: Table 2 As shown in Table 2, Example 1 exhibits the best tinting strength and weather resistance, demonstrating the superiority of the dual modification process. Comparative Example 4, modified only by plasma grafting, has an incomplete pigment surface coating, resulting in limited tinting strength and weather resistance. Comparative Example 5, modified only by in-situ polymerization coating, has weak bonding between the pigment and the coating layer, making it prone to peeling, and its modification effect is inferior to that of dual modification. Comparative Example 6 uses unmodified pigments, which have a large difference in surface polarity from the carrier, resulting in poor compatibility, severe agglomeration, low tinting strength, and the lack of a modified layer for protection, making the pigment susceptible to degradation by ultraviolet light and significantly increasing color difference.

[0071] Experiment 3: Verification test on the compounding effect of weather-resistant synergistic additives; Using Example 1 as the baseline, three comparative examples were designed, varying the composition or proportion of the weather-resistant synergistic agent while maintaining the same preparation conditions as Example 1. Each group of masterbatches was mixed with PPR substrate at a ratio of 1:50 and injection molded into standard specimens. These specimens were then subjected to xenon arc aging for 2000 hours according to GB / T16422.2-2014. The color difference ΔE and tensile strength retention rate were tested (a higher retention rate indicates better weather resistance). The results are as follows: Table 3 As shown in Table 3, Example 1 exhibits the best weather resistance, demonstrating the synergistic effect of a specific compound ratio of weather-resistant additives. UV-531 absorbs ultraviolet light, while HALS944 captures free radicals. When the two are compounded at a ratio of 1.5:1, their functions complement each other, resulting in the best protective effect. Comparative Examples 7 and 8 use only a single weather-resistant additive, which cannot simultaneously achieve ultraviolet light absorption and free radical capture, resulting in insufficient weather resistance. Comparative Example 9 changes the compounding ratio to 1:1, disrupting the synergistic balance between the two, leading to a decrease in ultraviolet protection efficiency, increased color difference, and reduced tensile strength retention.

[0072] Experiment 4: Verification experiment on the influence of dynamic crosslinking agent type; Using Example 1 as the baseline, three comparative groups were designed, with the type of dynamic crosslinking agent changed or the crosslinking agent removed, while the other preparation conditions remained the same as in Example 1. The masterbatch from each group was mixed with PPR substrate at a ratio of 1:50 and injection molded into standard specimens. The melt flow rate (MFR, 190℃ / 2.16kg) was tested according to GB / T3682.1-2018, and the impact strength was tested according to GB / T1843-2008. The results are as follows: Table 4 As shown in Table 4, Example 1 exhibits the best processing fluidity and impact strength, demonstrating the suitability of zinc dithiocarbamate as a dynamic crosslinking agent. Comparative Example 10, using sulfur, resulted in an excessively rapid crosslinking reaction rate, easily leading to localized over-crosslinking and affecting toughness. Comparative Example 11, using DCP, exhibited low crosslinking efficiency and poor crosslinking network stability, resulting in unsatisfactory processing fluidity and impact strength. Comparative Example 12, lacking a dynamic crosslinking agent, suffered from a lack of crosslinking network support, leading to pigment agglomeration, insufficient toughness, and the lowest impact strength. Furthermore, its excessively high melt flow rate resulted in insufficient stability during processing.

[0073] Experiment 5: Verification test on the influence of processing parameters; Using Example 1 as the baseline, three comparative groups were designed, changing the key process parameters in the preparation of the color masterbatch while keeping the other preparation conditions the same as in Example 1. Each group of color masterbatch was mixed with PPR substrate at a ratio of 1:50 and injection molded into standard test strips. The color difference ΔE was tested by xenon arc aging for 1000 hours according to GB / T16422.2-2014, and the moisture content of the mixture was also tested. The results are as follows: Table 5 As shown in Table 5, the process parameter combination in Example 1 is optimal, ensuring the overall performance of the masterbatch. In Comparative Example 13, the mixing temperature was too low and the rotation speed insufficient, resulting in uneven material mixing, excessive moisture content, severe pigment agglomeration, accelerated aging due to residual moisture, and increased color difference. In Comparative Example 14, the extrusion temperature was too low and the rotation speed insufficient, leading to inadequate melt blending and affecting weatherability. In Comparative Example 15, the drying time was insufficient, the material moisture content did not meet the standard, and moisture easily formed bubbles during processing, disrupting the uniformity of pigment dispersion. Simultaneously, residual moisture accelerated aging, resulting in increased color difference.

[0074] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0075] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A high-weather-resistant and highly dispersible PPR pipe color masterbatch, characterized in that, By weight, it includes the following components: 45-55 parts of composite functional carrier system, 22-28 parts of dual modified pigment, 6-8 parts of weather-resistant synergist, and 2-4 parts of processing aid; The composite functional carrier system is composed of the following components by mass percentage: 63-67% compatibility carrier resin, 6-8% interface modifier, 0.8-1.5% dynamic crosslinking agent, and the balance being vinyl elastomer; The vinyl elastomer is an ethylene-octene copolymer; The compatibility carrier resin is a compound of homopolymer polypropylene and maleic anhydride-grafted polypropylene with a mass ratio of 4:

1. The dual-modified pigment is an inorganic pigment that has been modified by plasma grafting and then coated by in-situ polymerization. The mixed monomers of the in-situ polymerization are composed of methyl methacrylate, hydroxyethyl acrylate and γ-glycidoxypropyltrimethoxysilane in a mass ratio of 18:9:

3. The dynamic crosslinking agent is zinc dithiocarbamate.

2. The high weather resistance and high dispersibility PPR pipe color masterbatch according to claim 1, characterized in that, The preparation method of the composite functional carrier system includes the following steps: S1 mixes vinyl elastomer, homopolymer polypropylene, and maleic anhydride-grafted polypropylene in a certain proportion, adds them to a high-speed mixer, and mixes them at 85-90℃ and 900-1000rpm for 12-15 minutes to obtain a premix. S2 adds the premixed material to a twin-screw extruder with a length-to-diameter ratio of 40:1 for melt blending and extrusion. The temperatures of each section of the extruder are: Zone 1 145-150℃, Zone 2 165-170℃, Zone 3 180-185℃, Zone 4 185-190℃, and the die head 180-185℃. The screw speed is 350-400 rpm. After extrusion, the material is sprayed with water for cooling and pelletized to obtain composite carrier particles. S3 mixes the composite carrier particles with an interface modifier and a dynamic crosslinking agent, and stirs them at 65-70℃ and 550-600rpm for 6-8 minutes to obtain a composite functional carrier system.

3. The high weather resistance and high dispersibility PPR pipe color masterbatch according to claim 1, characterized in that, The preparation method of the dual-modified pigment includes the following steps: a. Plasma grafting modification: Inorganic pigments are placed in a plasma processor with a vacuum of 15-20 Pa. A mixture of argon and acrylic acid with a volume ratio of 10:1 is introduced, with a discharge power of 120-150 W and a processing time of 18-20 min to obtain grafted modified pigments. b. In-situ polymerization coating modification: The grafted modified pigment is dispersed in deionized water and ultrasonically dispersed. Then, an emulsifier and an initiator are added, the temperature is raised to 75-80℃, and mixed monomers are added dropwise over a period of 2.5-3 hours. The reaction is maintained at this temperature for 4.5-5 hours. After the reaction is completed, the pigment is centrifuged, washed, and dried at 80℃ for 4 hours to obtain the double-modified pigment.

4. The high weather resistance and high dispersibility PPR pipe color masterbatch according to claim 3, characterized in that, The initiator is ammonium persulfate, and the amount used is 1.0% of the mass of the mixed monomers; the emulsifier is sodium dodecyl sulfate, and the amount used is 3.5% of the mass of the mixed monomers.

5. The high weather resistance and high dispersibility PPR pipe color masterbatch according to claim 3, characterized in that, The ultrasonic dispersion power is 300-400W, and the dispersion time is 30-40min.

6. The high weather resistance and high dispersibility PPR pipe color masterbatch according to claim 1, characterized in that, The inorganic pigment is one or more of titanium dioxide, carbon black, and iron oxide red.

7. The high weather resistance and high dispersibility PPR pipe color masterbatch according to claim 1, characterized in that, The interface modifier is γ-aminopropyltriethoxysilane.

8. The high weather resistance and high dispersibility PPR pipe color masterbatch according to claim 1, characterized in that, The weather-resistant synergist is a compound of UV absorber UV-531 and hindered amine light stabilizer HALS944, with a mass ratio of 1.5:1, and the mass ratio of the weather-resistant synergist to the dual-modified pigment is 1:2.

5.

9. The high weather resistance and high dispersibility PPR pipe color masterbatch according to claim 1, characterized in that, The processing aids include antioxidants and lubricants. The antioxidant is a compound of 1010 and 168 in a mass ratio of 1:1, and the lubricant is calcium stearate. The mass ratio of antioxidant to lubricant is 2.5:

1.

10. A method for preparing a high weather-resistant and highly dispersible PPR pipe color masterbatch as described in any one of claims 1-9, characterized in that, Includes the following steps: (1) Weigh each component according to the mass ratio, add it to a high-speed mixer, mix at 95-100℃ and 1100-1200rpm for 18-20min, and control the moisture content of the mixture to ≤0.3% to obtain the mixture. (2) Add the mixture to a twin-screw extruder with a length-to-diameter ratio of 40:1 and melt-blend and extrude. The temperatures of each section of the extruder are: Zone 1 155-160℃, Zone 2 175-180℃, Zone 3 190-195℃, Zone 4 195-200℃, and the die head 190-195℃. The screw speed is 380-420 rpm. (3) The extruded material is cooled with water, pelletized, and dried at 80℃ for 2.5-3 hours to obtain highly weather-resistant and highly dispersible PPR pipe color masterbatch; The color masterbatch is mixed with the PPR substrate at a mass ratio of 1:50-60.

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