Composite color master batch, preparation method and application thereof

Abstract

The application discloses a kind of composite color master batch and preparation method and application, belong to color master batch preparation technical field.A kind of composite color master batch, by 100 weight parts, the composite color master batch includes injection molding grade PP resin 30-36 parts, EVA 4-8 parts, POE 3-7 parts, double-layer functional CaO water-removing composite particles 14-22 parts, no heavy metal pigment 12-20 parts, inorganic filler 10-18 parts, dispersing lubricant 2-5 parts, antioxidant 0.5-1.0 parts and light stabilizer 0.5-1.5 parts.The composite color master batch prepared by the above-mentioned substance has water-removing, coloring and excellent mechanical properties and aging stability.

Description

Technical Field

[0001] This invention belongs to the field of color masterbatch preparation technology, specifically relating to a composite color masterbatch, its preparation method, and its application. Background Technology

[0002] Polypropylene (PP) has advantages such as low density, good processability, and moderate cost, and is widely used in daily necessities, packaging, household appliance parts, automotive interior and exterior parts, and other injection-molded products. To impart stable colors to PP products, color masterbatches are commonly used in industrial production. Existing PP color masterbatches generally consist of a PP carrier, color powder, dispersant, filler, and heat stabilizer, and are prepared through mixing and melt blending granulation. They can be used for coloring PP extrusion, spinning, and injection-molded products.

[0003] However, in actual PP injection molding, the PP resin to be processed, recycled PP, or reused PP often contains trace amounts of moisture. This trace moisture easily forms appearance defects such as silver streaks, bubbles, pitting, and localized whitening during injection molding and filling. Current production methods typically address coloring, defoaming, filling, and anti-aging issues by adding color masterbatch, defoaming masterbatch, filler masterbatch, and anti-aging masterbatch separately. However, adding multiple masterbatches separately introduces problems such as metering errors, uneven mixing, localized agglomeration, and batch-to-batch fluctuations, easily leading to black spots, color differences, silver streaks, bubbles, and a decrease in mechanical properties.

[0004] Calcium oxide, a commonly used dehydrating component, reacts with water to reduce the moisture content in polymer melts. Existing CaO defoaming masterbatches typically achieve dehydration by adding CaO, carrier resin, wax dispersants, and other additives. However, ordinary CaO particles are highly reactive and easily absorb moisture from the air during storage, opening, mixing, and transportation, reducing their effective dehydration capacity when entering the injection molding melt. Simply increasing the amount of CaO can easily lead to particle agglomeration, increased black spots, rough product surface, and decreased impact strength.

[0005] Furthermore, components such as CaO, titanium dioxide, carbon black, talc, calcium carbonate, and barium sulfate are all inorganic or highly polar powders, which have poor compatibility with the non-polar PP matrix. Improving flowability solely with ordinary wax-based dispersants is insufficient to simultaneously achieve low black points, low color difference, low silver streaks and bubbles, and high mechanical strength retention. Although grafted PP or grafted POE are used in existing PP filler masterbatches to improve the compatibility between fillers and PP, these compatibilizers are typically added as standard formulation components and lack a structured design to address the storage failure of CaO dehydration particles, dehydration and defoaming during injection molding, and the synergistic dispersion of pigments and fillers.

[0006] Therefore, it is necessary to provide a new composite masterbatch that can achieve stable coloring, dewatering and defoaming, filling modification and anti-aging at a low addition amount in PP injection molding, and maintain good dewatering and defoaming effect after storage or open placement. Summary of the Invention

[0007] The purpose of this invention is to provide a composite color masterbatch, its preparation method, and its application, to solve the problems in existing PP injection molding processes where uneven dispersion, black spots, silver streaks, bubbles, color differences, and decreased mechanical properties are easily caused when color masterbatch, defoaming masterbatch, filler masterbatch, and anti-aging masterbatch are added separately, as well as the reduced dehydration and defoaming effect caused by premature moisture absorption of ordinary CaO dehydrating agent during storage or opening.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a composite masterbatch, which, based on 100 parts by weight, comprises 30-36 parts of injection molding grade PP resin, 4-8 parts of EVA, 3-7 parts of POE, 14-22 parts of bilayer functionalized CaO dehydration composite particles, 12-20 parts of heavy metal-free pigment, 10-18 parts of inorganic filler, 2-5 parts of dispersing lubricant, 0.5-1.0 parts of antioxidant, and 0.5-1.5 parts of light stabilizer. The double-layer functionalized CaO dehydration composite particles, based on 100 parts by weight, include 78-88 parts of CaO core, 5-10 parts of inner functional layer, and 6-12 parts of outer compatibility layer. The particle size of the CaO core is 600-1250 mesh; The inner functional layer is formed of titanate coupling agent and / or aluminate coupling agent, oxidized polyethylene wax and stearate; The outer compatibility layer is formed by maleic anhydride-grafted PP and / or maleic anhydride-grafted POE, wherein the grafting rate of the maleic anhydride-grafted PP and / or maleic anhydride-grafted POE is 0.5-1.5%, and the melt mass flow rate is 50-150 g / 10 min.

[0009] Preferably, the inner functional layer comprises 1-3 parts of titanate coupling agent and / or aluminate coupling agent, 2-5 parts of oxidized polyethylene wax, and 1-3 parts of calcium stearate and / or zinc stearate; the outer compatibility layer comprises 6-12 parts of maleic anhydride-grafted PP and / or maleic anhydride-grafted POE.

[0010] Preferably, the effective calcium oxide content of the CaO core is not less than 85 wt%, the moisture content before feeding is not more than 0.5 wt%, and the moisture content of the double-layer functionalized CaO dehydration composite particles is not more than 0.3 wt%.

[0011] Preferably, the heavy metal-free pigment is selected from one or more of titanium dioxide, carbon black, phthalocyanine blue, phthalocyanine green, quinacridone pigment, azo condensation pigment, and anthraquinone pigment, and does not contain lead chromium yellow, molybdenum chromium red, cadmium red, cadmium yellow, or chromate pigment.

[0012] Preferably, the inorganic filler is selected from one or more of talc, calcium carbonate, and barium sulfate, wherein the fineness of the talc is 2000-5000 mesh, the fineness of the calcium carbonate is 1250-3000 mesh, and the fineness of the barium sulfate is 2000-5000 mesh.

[0013] Preferably, the dispersing lubricant includes at least two of oxidized polyethylene wax, PP wax, EBS and amide wax; the antioxidant includes antioxidant 1010 and antioxidant 168 in a mass ratio of 1:0.5-2; and the light stabilizer includes hindered amine light stabilizers and / or benzotriazole UV absorbers.

[0014] Preferably, the composite masterbatch is in the form of columnar particles with a length of 2.5-3.5 mm and a particle size of 2.0-3.5 mm. After being sealed and stored at 40°C and 75% RH for 90 days, the composite masterbatch does not exhibit significant agglomeration. Furthermore, when added at 4 wt% to PP resin with a moisture content of 0.08-0.12 wt% for injection molding, it achieves a 100 cm³ / g elongation. 2 The total number of silver threads and bubbles in the sample is ≤5.

[0015] Preferably, the method for preparing a composite color masterbatch includes the following steps: Step 1: Dry the injection molding grade PP resin, EVA and POE at 70-90℃ for 1-3 hours; dry the heavy metal-free pigments and inorganic fillers at 90-110℃ for 1-2 hours; Step 2: Add CaO, titanate coupling agent and / or aluminate coupling agent, oxidized polyethylene wax and stearate to a high-speed mixer and treat at 90-110℃ and 800-1000r / min for 8-15min to form an inner functional layer on the CaO surface; then graft maleic anhydride onto PP and / or maleic anhydride onto POE and mix at 110-130℃ for 5-10min to obtain bilayer functionalized CaO dehydration composite particles. Step 3: Mix the double-layer functionalized CaO dehydration composite particles, heavy metal-free pigments, inorganic fillers and part of the dispersing lubricant at 70-95℃ and 600-900r / min for 5-8min to obtain the pre-dispersed material; Step 4: Add injection-grade PP resin, EVA, POE, remaining dispersant lubricant, antioxidant, and light stabilizer to the pre-dispersed material, and mix at 75-90℃ for 5-10 minutes to obtain the total mixture; feed the total mixture into a co-rotating twin-screw extruder for melt extrusion. The twin-screw extruder has a length-to-diameter ratio of 36-48, a screw speed of 250-350 r / min, and a vacuum degree of -0.06 to -0.09 MPa in the vacuum exhaust section. The temperature zones of the twin-screw extruder are as follows: Zone 1 160-170℃, Zone 2 175-185℃, Zone 3 185-195℃, Zone 4 195-205℃, Zone 5 200-210℃, Zone 6 200-210℃, Zone 7 195-205℃, and Die Head 200-210℃. Step 5: Cool the extrudate, granulate it, and dry it at 70-80℃ for 2-3 hours to obtain the composite masterbatch.

[0016] An application of a composite masterbatch, in which the obtained composite masterbatch is applied to PP injection molded products.

[0017] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. The composite masterbatch of the present invention employs bilayer functionalized CaO dehydration composite particles with an inner functional layer and an outer compatibility layer. Compared with directly adding untreated CaO or controlling the initial moisture content of the masterbatch solely through drying, the bilayer functionalized CaO dehydration composite particles can continuously absorb trace amounts of moisture in the system during PP injection molding melt processing, thereby reducing appearance defects such as silver streaks and bubbles caused by moisture vaporization. Simultaneously, during storage, it can reduce the probability of CaO prematurely contacting external moisture, reducing the decrease in dehydration efficiency caused by premature CaO moisture absorption. Its mechanism of action lies in the fact that the CaO core provides dynamic dehydration capability during the melt processing stage, the inner functional layer improves the hydrophobicity and interfacial wettability of the CaO surface, and the outer compatibility layer enhances the coating stability and dispersion stability of CaO particles in the PP matrix, thus enabling the composite masterbatch to possess both dehydration and defoaming properties and storage stability.

[0018] 2. This invention provides an external compatibility layer formed by maleic anhydride-grafted PP and / or maleic anhydride-grafted POE on the outer surface of double-layer functionalized CaO dehydration composite particles, and combines it with injection-grade PP resin, EVA, and POE to form a composite carrier system. Compared with systems that simply add CaO and inorganic fillers, even under conditions with high CaO and inorganic filler content, particle agglomeration and black spot formation can be reduced, while maintaining high tensile strength and notched impact strength of PP injection molded products. This is because the maleic anhydride graft can form an interfacial bond between the inorganic particles and the PP matrix, and EVA and POE can act as flexible phases to disperse stress, thereby improving interfacial bonding stability and toughness retention.

[0019] 3. In the preparation process of this invention, the double-layer functionalized CaO dehydration composite particles, heavy metal-free pigments, inorganic fillers, and a portion of the dispersing lubricant are first pre-dispersed, and then mixed with the carrier resin and other additives for extrusion. Through this pre-dispersion treatment, the high-pigment, high-filler system can still maintain good dispersion uniformity, reducing black spots, color patches, and color difference fluctuations. This is because the dispersing lubricant can preferentially wet and coat the surfaces of the pigments, fillers, and CaO particles, reducing inter-particle friction and secondary agglomeration, and improving the subsequent twin-screw melt shear dispersion effect.

[0020] 4. This invention introduces an antioxidant and light-stabilizing system into the composite masterbatch, consisting of antioxidant 1010, antioxidant 168, hindered amine light stabilizers, and / or benzotriazole UV absorbers. Through the synergistic effect of this system, the composite masterbatch maintains good initial appearance and mechanical properties while exhibiting low color difference and high tensile strength retention after thermal and photo-aging. This is because antioxidant 1010 and antioxidant 168 synergistically inhibit the thermo-oxidative degradation of PP, and the light stabilizer absorbs UV energy and captures photo-aging free radicals, thereby slowing down resin degradation and pigment discoloration.

[0021] 5. This invention synergistically combines double-layer functionalized CaO dehydrating composite particles, heavy metal-free pigments, inorganic fillers, PP / EVA / POE composite carriers, dispersing lubricants, and an antioxidant light-stabilizing system to form a composite masterbatch with dehydration, coloring, dispersion, toughening, and stabilization functions. Compared with single dehydrating masterbatches or ordinary coloring masterbatches, the composite masterbatch can reduce silver streaks, bubbles, black spots, and color difference fluctuations even at lower addition levels, while maintaining better mechanical properties and aging stability. This is because the components form a stable composite dispersion structure through interfacial coating, compatibility toughening, and pre-dispersion. Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1: This example discloses a method for preparing composite color masterbatch, including the following steps: Step 1: Raw material weighing and drying: Weigh out 33.5 parts of injection molding grade PP resin, 6.0 parts of EVA, 5.0 parts of POE, 18.0 parts of double-layer functionalized CaO dehydrating composite particles A, 16.0 parts of heavy metal-free pigment, 16.0 parts of inorganic filler, 3.5 parts of dispersing lubricant, 0.8 parts of antioxidant, and 1.2 parts of light stabilizer per 100 parts. The heavy metal-free pigment is composed of 12.0 parts titanium dioxide, 3.0 parts phthalocyanine blue, and 1.0 part carbon black; the inorganic filler is composed of 10.0 parts 3000-mesh talc and 6.0 parts 3000-mesh barium sulfate; the dispersing lubricant is composed of 1.8 parts oxidized polyethylene wax, 1.0 part PP wax, and 0.7 parts EBS; the antioxidant is composed of 0.4 parts antioxidant 1010 and 0.4 parts antioxidant 168; and the light stabilizer is composed of 0.8 parts hindered amine light stabilizer and 0.4 parts benzotriazole UV absorber. Injection molding grade PP resin, EVA, and POE were dried at 80℃ for 2 hours; heavy metal-free pigments and inorganic fillers were dried at 105℃ for 1.5 hours. Step 2: Preparation of bilayer functionalized CaO dehydration composite particles: Bilayer functionalized CaO dehydration composite particle A, based on 100 parts of itself, consists of 84.0 parts of CaO core, 2.0 parts of titanate coupling agent, 4.0 parts of oxidized polyethylene wax, 2.0 parts of calcium stearate, 6.0 parts of MAH-g-PP, and 2.0 parts of MAH-g-POE; the CaO core is 1000-mesh activated calcium oxide with an effective calcium oxide content of 90.6 wt% and a moisture content of 0.28 wt% before feeding. CaO, titanate coupling agent, oxidized polyethylene wax and calcium stearate were added to a high-speed mixer and treated at 100℃ and 900r / min for 12min to form an inner functional layer on the surface of CaO; then MAH-g-PP and MAH-g-POE were added and mixed at 120℃ for 8min to obtain bilayer functionalized CaO dehydration composite particles A. Step 3: Preparation of pre-dispersion material: Add 2.1 parts of the double-layer functionalized CaO dehydration composite particles A obtained in Step 2, dried heavy metal-free pigments, inorganic fillers, and dispersing lubricants to a high-speed mixer and mix at 85℃ and 750r / min for 6min to obtain the pre-dispersion material; Step 4: Total Mixing and Melt Extrusion: Add the dried injection-grade PP resin, EVA, POE, the remaining 1.4 parts of dispersant lubricant, antioxidant and light stabilizer to the pre-dispersed material obtained in Step 3, and mix at 82°C for 8 minutes to obtain the total mixture; The total mixture is fed into a co-rotating twin-screw extruder for melt extrusion. The twin-screw extruder has a length-to-diameter ratio of 44, a screw speed of 300 r / min, and a vacuum degree of -0.08 MPa in the vacuum exhaust section. The temperature zones are as follows: Zone 1 165℃, Zone 2 180℃, Zone 3 190℃, Zone 4 200℃, Zone 5 205℃, Zone 6 205℃, Zone 7 200℃, and Die Head 205℃. Step 5: Cooling, pelletizing and drying: After cooling the extrudate obtained in Step 4 in a 30°C water bath, the extrudate is stretched and pelletized, with the pellet length controlled at 2.5-3.5 mm and the pellet diameter at 2.0-3.5 mm; then dried at 75°C for 2.5 h to obtain composite masterbatch.

[0024] Example 2: This example discloses a method for preparing composite masterbatch, including the following steps: Step 1: Raw material weighing and drying: Weigh out 31.0 parts of injection molding grade PP resin, 5.0 parts of EVA, 6.0 parts of POE, 22.0 parts of double-layer functionalized CaO dehydrating composite particles B, 13.0 parts of heavy metal-free pigment, 17.0 parts of inorganic filler, 3.8 parts of dispersing lubricant, 0.7 parts of antioxidant, and 1.5 parts of light stabilizer per 100 parts. The heavy metal-free pigment is composed of 10.0 parts titanium dioxide and 3.0 parts phthalocyanine blue; the inorganic filler is composed of 8.0 parts 3000-mesh talc and 9.0 parts 2000-mesh barium sulfate; the dispersing lubricant is composed of 2.0 parts oxidized polyethylene wax, 1.0 part EBS, and 0.8 parts amide wax; the antioxidant is composed of 0.3 parts antioxidant 1010 and 0.4 parts antioxidant 168; and the light stabilizer is composed of 1.0 part hindered amine light stabilizer and 0.5 parts benzotriazole ultraviolet absorber. Injection molding grade PP resin, EVA, and POE were dried at 85°C for 2 hours; heavy metal-free pigments and inorganic fillers were dried at 105°C for 1.5 hours. Step 2: Preparation of bilayer functionalized CaO dehydration composite particles: Bilayer functionalized CaO dehydration composite particle B, based on 100 parts of itself, consists of 78.0 parts of CaO core, 3.0 parts of aluminate coupling agent, 5.0 parts of oxidized polyethylene wax, 2.0 parts of zinc stearate, and 12.0 parts of MAH-g-POE; the CaO core is 1250 mesh activated calcium oxide with an effective calcium oxide content of 92.0 wt% and a moisture content of 0.22 wt% before feeding. CaO, aluminate coupling agent, oxidized polyethylene wax and zinc stearate were added to a high-speed mixer and treated at 105℃ and 950r / min for 10min to form an inner functional layer on the surface of CaO; then MAH-g-POE was added and mixed at 125℃ for another 8min to obtain bilayer functionalized CaO dehydration composite particles B. Step 3: Preparation of pre-dispersion material: Add 2.4 parts of the double-layer functionalized CaO dehydration composite particles B obtained in Step 2, dried heavy metal-free pigments, inorganic fillers, and dispersing lubricants to a high-speed mixer and mix at 90℃ and 800r / min for 6min to obtain the pre-dispersion material; Step 4: Total Mixing and Melt Extrusion: Add dried injection-grade PP resin, EVA, POE, the remaining 1.4 parts of dispersant lubricant, antioxidant and light stabilizer to the pre-dispersed material obtained in Step 3, and mix at 85°C for 8 minutes to obtain the total mixture; The total mixture is fed into a co-rotating twin-screw extruder for melt extrusion. The twin-screw extruder has a length-to-diameter ratio of 44, a screw speed of 320 r / min, and a vacuum degree of -0.085 MPa in the vacuum exhaust section. The temperature zones are as follows: Zone 1 165℃, Zone 2 180℃, Zone 3 190℃, Zone 4 200℃, Zone 5 205℃, Zone 6 208℃, Zone 7 202℃, and Die Head 205℃. Step 5: Cooling, pelletizing and drying: After water cooling, the extrudate obtained in step 4 is stretched and pelletized, with the pellet length controlled at 2.5-3.5 mm and the pellet diameter at 2.0-3.5 mm; then dried at 75℃ for 3 hours to obtain composite masterbatch.

[0025] Example 3: This example discloses a method for preparing composite color masterbatch, including the following steps: Step 1: Raw material weighing and drying: Weigh out 36.0 parts of injection molding grade PP resin, 4.0 parts of EVA, 3.5 parts of POE, 14.0 parts of double-layer functionalized CaO dehydrating composite particles C, 18.0 parts of heavy metal-free pigments, 18.0 parts of inorganic fillers, 4.0 parts of dispersing lubricant, 1.0 part of antioxidant, and 1.5 parts of light stabilizer per 100 parts. The heavy metal-free pigment is composed of 14.0 parts titanium dioxide and 4.0 parts quinacridone pigment; the inorganic filler is composed of 12.0 parts 3000-mesh talc and 6.0 parts 3000-mesh barium sulfate; the dispersing lubricant is composed of 1.5 parts oxidized polyethylene wax, 1.0 part EBS, and 1.5 parts PP wax; the antioxidant is composed of 0.6 parts antioxidant 1010 and 0.4 parts antioxidant 168; and the light stabilizer is composed of 1.0 part hindered amine light stabilizer and 0.5 parts benzotriazole UV absorber. Injection molding grade PP resin, EVA, and POE were dried at 80℃ for 2 hours; heavy metal-free pigments and inorganic fillers were dried at 110℃ for 1.5 hours. Step 2: Preparation of bilayer functionalized CaO dehydration composite particles: Bilayer functionalized CaO dehydration composite particles C, based on 100 parts of themselves, consist of 88.0 parts of CaO core, 1.5 parts of titanate coupling agent, 3.0 parts of oxidized polyethylene wax, 1.5 parts of calcium stearate, and 6.0 parts of MAH-g-PP; the CaO core is 800-mesh activated calcium oxide with an effective calcium oxide content of 88.5 wt% and a moisture content of 0.31 wt% before feeding. CaO, titanate coupling agent, oxidized polyethylene wax and calcium stearate were added to a high-speed mixer and treated at 95℃ and 850r / min for 15min to form an inner functional layer on the surface of CaO; then MAH-g-PP was added and mixed at 115℃ for 10min to obtain double-layer functionalized CaO dehydration composite particles C. Step 3: Preparation of pre-dispersion material: Add 2.5 parts of the double-layer functionalized CaO dehydration composite particles C obtained in Step 2, the dried heavy metal-free pigment, inorganic filler and dispersing lubricant to a high-speed mixer and mix at 85℃ and 700r / min for 8min to obtain the pre-dispersion material; Step 4: Total Mixing and Melt Extrusion: Add dried injection-grade PP resin, EVA, POE, the remaining 1.5 parts of dispersant lubricant, antioxidant and light stabilizer to the pre-dispersed material obtained in Step 3, and mix at 80°C for 10 min to obtain the total mixture; The total mixture is fed into a co-rotating twin-screw extruder for melt extrusion. The twin-screw extruder has a length-to-diameter ratio of 40, a screw speed of 280 r / min, and a vacuum degree of -0.075 MPa in the vacuum exhaust section. The temperature zones are as follows: Zone 1 160℃, Zone 2 178℃, Zone 3 188℃, Zone 4 198℃, Zone 5 205℃, Zone 6 205℃, Zone 7 200℃, and Die Head 205℃. Step 5: Cooling, pelletizing and drying: After cooling, the extrudate obtained in Step 4 is stretched and pelletized, with the pellet length controlled at 2.5-3.5 mm and the pellet diameter at 2.0-3.5 mm; then dried at 75℃ for 2.5 h to obtain composite masterbatch.

[0026] Example 4: This example discloses a method for preparing composite color masterbatch, including the following steps: Step 1: Raw material weighing and drying: Weigh out 30.0 parts of injection molding grade PP resin, 8.0 parts of EVA, 7.0 parts of POE, 16.0 parts of double-layer functionalized CaO dehydrating composite particles D, 20.0 parts of heavy metal-free pigments, 12.0 parts of inorganic fillers, 5.0 parts of dispersing lubricant, 0.5 parts of antioxidant, and 1.5 parts of light stabilizer per 100 parts. The heavy metal-free pigment is composed of 12.0 parts titanium dioxide, 6.0 parts azo condensation pigment, and 2.0 parts carbon black; the inorganic filler is composed of 8.0 parts 2000-mesh calcium carbonate and 4.0 parts 3000-mesh barium sulfate; the dispersing lubricant is composed of 2.2 parts oxidized polyethylene wax, 1.3 parts EBS, and 1.5 parts PP wax; the antioxidant is composed of 0.2 parts antioxidant 1010 and 0.3 parts antioxidant 168; and the light stabilizer is composed of 1.0 part hindered amine light stabilizer and 0.5 parts benzotriazole ultraviolet absorber. Injection molding grade PP resin, EVA, and POE were dried at 75°C for 3 hours; heavy metal-free pigments and inorganic fillers were dried at 100°C for 2 hours. Step 2: Preparation of bilayer functionalized CaO dehydration composite particles: Bilayer functionalized CaO dehydration composite particles D, based on 100 parts of themselves, consist of 82.0 parts of CaO core, 2.0 parts of titanate coupling agent, 4.0 parts of oxidized polyethylene wax, 2.0 parts of a mixture of calcium stearate and zinc stearate (the mass ratio of calcium stearate to zinc stearate is 1:1), 5.0 parts of MAH-g-PP, and 5.0 parts of MAH-g-POE; the CaO core is 600-mesh activated calcium oxide with an effective calcium oxide content of 87.8 wt% and a moisture content of 0.35 wt% before feeding. A mixture of CaO, titanate coupling agent, oxidized polyethylene wax, calcium stearate, and zinc stearate was added to a high-speed mixer and treated at 100℃ and 900r / min for 12min to form an inner functional layer on the surface of CaO. Then, MAH-g-PP and MAH-g-POE were added, and the mixture was further mixed at 120℃ for 8min to obtain bilayer functionalized CaO dehydration composite particles D. Step 3: Preparation of pre-dispersion material: Add 3.2 parts of the double-layer functionalized CaO dehydration composite particles D obtained in Step 2, dried heavy metal-free pigments, inorganic fillers, and dispersing lubricants to a high-speed mixer and mix at 90℃ and 850r / min for 6min to obtain the pre-dispersion material; Step 4: Total Mixing and Melt Extrusion: Add dried injection-grade PP resin, EVA, POE, the remaining 1.8 parts of dispersant lubricant, antioxidant and light stabilizer to the pre-dispersed material obtained in Step 3, and mix at 85°C for 8 minutes to obtain the total mixture; The total mixture is fed into a co-rotating twin-screw extruder for melt extrusion. The twin-screw extruder has a length-to-diameter ratio of 48, a screw speed of 330 r / min, and a vacuum degree of -0.085 MPa in the vacuum exhaust section. The temperature zones are as follows: Zone 1 168℃, Zone 2 182℃, Zone 3 192℃, Zone 4 202℃, Zone 5 208℃, Zone 6 208℃, Zone 7 202℃, and Die Head 208℃. Step 5: Cooling, pelletizing and drying: After cooling, the extrudate obtained in Step 4 is stretched and pelletized, with the pellet length controlled at 2.5-3.5 mm and the pellet diameter at 2.0-3.5 mm; then dried at 80℃ for 2 hours to obtain composite masterbatch.

[0027] Example 5: This example discloses a method for preparing composite color masterbatch, including the following steps: Step 1: Raw material weighing and drying: Weigh out 35.0 parts of injection molding grade PP resin, 5.0 parts of EVA, 4.0 parts of POE, 20.0 parts of double-layer functionalized CaO dehydrating composite particles E, 12.0 parts of heavy metal-free pigment, 18.0 parts of inorganic filler, 4.0 parts of dispersing lubricant, 0.8 parts of antioxidant, and 1.2 parts of light stabilizer per 100 parts. The heavy metal-free pigment is composed of 8.0 parts titanium dioxide, 2.0 parts anthraquinone pigment, and 2.0 parts phthalocyanine blue; the inorganic filler is composed of 6.0 parts 3000-mesh talc, 6.0 parts 2000-mesh calcium carbonate, and 6.0 parts 3000-mesh barium sulfate; the dispersing lubricant is composed of 2.0 parts oxidized polyethylene wax, 1.0 part PP wax, 0.6 parts EBS, and 0.4 parts amide wax; the antioxidant is composed of 0.4 parts antioxidant 1010 and 0.4 parts antioxidant 168; and the light stabilizer is composed of 0.8 parts hindered amine light stabilizer and 0.4 parts benzotriazole UV absorber. Injection molding grade PP resin, EVA, and POE were dried at 80℃ for 2.5 hours; heavy metal-free pigments and inorganic fillers were dried at 110℃ for 1 hour. Step 2: Preparation of bilayer functionalized CaO dehydration composite particles: Bilayer functionalized CaO dehydration composite particles E, based on 100 parts of themselves, consist of 80.0 parts of CaO core, 1.0 part of titanate coupling agent, 1.5 parts of aluminate coupling agent, 4.5 parts of oxidized polyethylene wax, 1.0 part of calcium stearate, 1.0 part of zinc stearate, 7.0 parts of MAH-g-PP, and 4.0 parts of MAH-g-POE; the CaO core is 1250 mesh activated calcium oxide with an effective calcium oxide content of 91.2 wt% and a moisture content of 0.25 wt% before feeding. CaO, titanate coupling agent, aluminate coupling agent, oxidized polyethylene wax, calcium stearate and zinc stearate were added to a high-speed mixer and treated at 105℃ and 950r / min for 15min to form an inner functional layer on the surface of CaO; then MAH-g-PP and MAH-g-POE were added and mixed at 125℃ for 10min to obtain bilayer functionalized CaO dehydration composite particles E. Step 3: Preparation of pre-dispersion material: Add 2.6 parts of the double-layer functionalized CaO dehydration composite particles E obtained in Step 2, dried heavy metal-free pigments, inorganic fillers, and dispersing lubricant to a high-speed mixer and mix at 88℃ and 800r / min for 7min to obtain the pre-dispersion material; Step 4: Total Mixing and Melt Extrusion: Add dried injection-grade PP resin, EVA, POE, the remaining 1.4 parts of dispersant lubricant, antioxidant and light stabilizer to the pre-dispersed material obtained in Step 3, and mix at 85°C for 10 min to obtain the total mixture; The total mixture is fed into a co-rotating twin-screw extruder for melt extrusion. The twin-screw extruder has a length-to-diameter ratio of 44, a screw speed of 300 r / min, and a vacuum degree of -0.09 MPa in the vacuum exhaust section. The temperature zones are as follows: Zone 1 165℃, Zone 2 180℃, Zone 3 190℃, Zone 4 200℃, Zone 5 210℃, Zone 6 210℃, Zone 7 205℃, and Die Head 210℃. Step 5: Cooling, pelletizing and drying: After cooling the extrudate obtained in Step 4 in a 30°C water bath, the extrudate is stretched and pelletized, with the pellet length controlled at 2.5-3.5 mm and the pellet diameter at 2.0-3.5 mm; then dried at 80°C for 2 hours to obtain composite masterbatch.

[0028] Comparative Example 1: Compared with Example 1, Comparative Example 1 did not add CaO cores, nor did it prepare bilayer functionalized CaO dehydration composite particles, and all other conditions remained unchanged.

[0029] Comparative Example 2: Compared with Example 1, Comparative Example 2 did not undergo internal functionalization of CaO or external compatibility treatment of CaO, and all other conditions remained unchanged.

[0030] Comparative Example 3: Compared with Example 1, Comparative Example 3 did not add MAH-g-PP and MAH-g-POE, and all other conditions remained unchanged.

[0031] Comparative Example 4: Compared with Example 4, Comparative Example 4 does not pre-mix the bilayer functionalized CaO dehydration composite particles D, heavy metal-free pigments, inorganic fillers and some dispersing lubricants into a pre-dispersed material, but directly performs a one-time total mixing and melt extrusion, while other conditions remain unchanged.

[0032] Comparative Example 5: Compared with Example 2, Comparative Example 5 did not add EVA and POE, and all other conditions remained unchanged.

[0033] Comparative Example 6: Compared with Example 3, Comparative Example 6 did not add antioxidants and light stabilizers, and all other conditions remained unchanged.

[0034] Performance testing: The composite masterbatches prepared in Examples 1-5 and Comparative Examples 1-6 were subjected to performance tests. The composite masterbatches were added to injection-grade PP resin at a dosage of 4 wt%. The PP resin had a melt flow rate of 10-30 g / 10 min and a moisture content of 0.08-0.12 wt%. After uniform mixing, the mixture was injection molded. Injection molded samples were prepared according to GB / T 17037.1-2019, GB / T17037.2-2020, and GB / T 17037.3-2003, and conditioned according to GB / T 2918-2018. Tensile properties were determined according to GB / T 1040.2-2022, notched impact strength according to GB / T 1843-2008, color difference according to GB / T 3979-2008 and GB / T 7921-2008, and pigment or carbon black dispersion according to GB / T The following tests were conducted: 18251-2019 for thermal aging, GB / T 7141-2008 for light aging, GB / T 16422.1-2019 and GB / T 16422.3-2022 for light aging, GB / T 6284-2006 for masterbatch moisture content, GB / T 9345.1-2008 for ash content, and GB / T 19077-2024 for inorganic powder particle size. The test results are shown in Table 1. Table 1 As shown in Table 1, the moisture content of the composite masterbatches obtained in Examples 1-5 was 0.10-0.13 wt%, and after 90 days of sealed storage, the moisture content was 0.12-0.16 wt%, indicating that the composite masterbatches of the present invention have low initial moisture content and good storage stability. The dispersion grade of Examples 1-5 was all Grade 1, with only 1-2 black spots / 400 cm², and 0-2 silver streaks and bubbles / 100 cm², all significantly better than most comparative examples. This indicates that the present invention, through the synergistic effect of double-layer functionalized CaO dehydration composite particles, composite carrier resin, and pre-dispersion process, can improve the dispersion state of pigments, inorganic fillers, and CaO in the PP system, and effectively reduce black spots, silver streaks, and bubble defects on the surface of injection molded products.

[0035] From a mechanical property perspective, the tensile strength retention rate of Examples 1-5 was 92.7-96.2%, and the notched impact strength retention rate was 86.4-92.8%, indicating that the present invention, while introducing CaO dehydrating components, pigments, and inorganic fillers, can still maintain the tensile and impact properties of PP injection molded products relatively well. The notched impact strength retention rates of Examples 1, 2, and 5 reached 92.8%, 89.6%, and 91.0%, respectively, indicating that EVA, POE, and MAH-g-PP and / or MAH-g-POE in the external compatibility layer can improve the interfacial bonding between inorganic components and the PP matrix, reducing the negative impact of inorganic powders on the toughness of the product.

[0036] Based on the color difference data, the initial color difference ΔE of Examples 1-5 was 0.58-0.86, the color difference ΔE after heat aging at 100℃ for 168h was 1.21-1.55, and the color difference ΔE after light aging was 1.34-1.68, all of which are at a low level, indicating that the composite masterbatch of the present invention has good initial coloring uniformity and color stability after aging. Meanwhile, the tensile strength retention rate of Examples 1-5 after heat aging was 87.6-91.8%, and the tensile strength retention rate after light aging was 86.8-90.6%, indicating that the antioxidant and light stabilizer system can effectively improve the heat-oxidative aging resistance and light aging resistance of PP injection molded products.

[0037] Compared to Example 1, Comparative Example 1 did not include a CaO core, nor was a double-layered functionalized CaO dehydration composite particle prepared. Although the masterbatch of Comparative Example 1 had a lower moisture content, its total number of silver streaks and bubbles reached 15 per 100 cm², significantly higher than the 1 per 100 cm² in Example 1, and the initial color difference ΔE increased from 0.58 in Example 1 to 1.21. This indicates that simply reducing the moisture content of the masterbatch itself cannot solve the problem of silver streaks and bubbles in the injection molding process of water-containing PP; the CaO core plays a crucial role in the absorption of trace amounts of moisture and defect suppression during the injection molding process.

[0038] Compared to Example 1, Comparative Example 2, although containing CaO and related additives, did not undergo internal functionalization or external compatibility treatment of CaO. The results showed that the moisture content of the masterbatch in Comparative Example 2 was 0.24 wt%, which increased to 0.38 wt% after 90 days of sealed storage, significantly higher than the 0.11 wt% and 0.13 wt% of Example 1. Simultaneously, Comparative Example 2 had 6 black spots per 400 cm², 4 silver threads and bubbles per 100 cm², and a notched impact strength retention rate of only 78.5%. This indicates that uncoated CaO is prone to premature moisture absorption and agglomeration, leading to decreased dispersibility, storage stability, and mechanical properties; while the double-layer functionalization treatment of this invention can reduce the risk of premature moisture absorption and agglomeration of CaO.

[0039] Compared to Example 1, Comparative Example 3 did not include the MAH-g-PP and MAH-g-POE external compatibility layers. The dispersion grade of Comparative Example 3 decreased to level 2, the number of black spots increased to 7 per 400 cm², and the notched impact strength retention rate decreased to 79.8%, significantly lower than the 92.8% of Example 1. This indicates that the external compatibility layer can improve the interfacial compatibility between CaO, pigments, and inorganic fillers and the PP matrix, allowing the inorganic components to be more uniformly dispersed in the PP system, thereby reducing black spots and improving the retention rate of mechanical properties.

[0040] Compared to Example 4, Comparative Example 4 eliminated the pre-dispersion steps involving the double-layer functionalized CaO dehydration composite particles, heavy metal-free pigments, inorganic fillers, and some dispersing lubricants, instead performing a direct one-time total mixing. The results showed that Comparative Example 4 had a dispersion grade of 3, with 11 black spots per 400 cm², and an initial color difference ΔE of 1.46, all significantly worse than the 1st grade, 2 black spots per 400 cm², and 0.86 of Example 4. This indicates that the pre-dispersion step can significantly improve the mixing uniformity in systems with high pigment and high inorganic filler content, thus helping to reduce black spots, color patches, and color difference fluctuations.

[0041] Compared to Example 2, Comparative Example 5 did not add EVA and POE. The notched impact strength retention rate of Comparative Example 5 was only 75.6%, significantly lower than the 89.6% of Example 2. Simultaneously, the dispersion grade of Comparative Example 5 was level 2, with 4 black spots per 400 cm², also inferior to Example 2. This indicates that EVA and POE not only improve the processing and dispersibility of the composite masterbatch but also play a toughening and interfacial buffering role in high-CaO and high-inorganic powder systems, thereby improving the impact performance retention rate of PP injection molded products.

[0042] Compared to Example 3, Comparative Example 6 did not contain any antioxidants or light stabilizers. The two examples showed little difference in masterbatch moisture content, ash content, dispersion grade, number of black spots, and number of silver bubbles, indicating that antioxidants and light stabilizers had minimal impact on initial dispersion and defoaming. However, after thermal aging at 100°C for 168 hours, the tensile strength retention rate of Comparative Example 6 was only 72.8%, and after light aging, it was only 68.5%, significantly lower than the 91.8% and 90.6% of Example 3, respectively. Simultaneously, the color difference ΔE of Comparative Example 6 increased to 3.46 after thermal aging and to 4.12 after light aging, also significantly higher than the 1.21 and 1.34 of Example 3, respectively. This demonstrates that the antioxidant and light stabilizer system has a significant effect on improving the thermo-oxidative stability, light stability, and color stability after aging of the material.

[0043] In summary, Examples 1-5 demonstrate superior performance in terms of moisture control, dispersion grade, number of black spots, number of silver bubbles, retention of mechanical properties, and color difference control after aging. The comparative examples, from the perspectives of the absence of a CaO core, lack of bilayer functionalization, absence of an external compatibility layer, absence of a pre-dispersion step, absence of an EVA / POE composite carrier, and absence of antioxidants / light stabilizers, respectively, demonstrate the necessity and synergistic effect of the technical features of this invention. Therefore, the composite masterbatch prepared by this invention possesses excellent dehydration and defoaming properties, pigment and filler dispersion performance, storage stability, mechanical property retention ability, and resistance to heat and light aging.

[0044] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0045] 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 specific implementations. 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 composite color masterbatch, characterized in that, Based on 100 parts by weight, the composite masterbatch comprises 30-36 parts of injection molding grade PP resin, 4-8 parts of EVA, 3-7 parts of POE, 14-22 parts of double-layer functionalized CaO dehydration composite particles, 12-20 parts of heavy metal-free pigment, 10-18 parts of inorganic filler, 2-5 parts of dispersing lubricant, 0.5-1.0 parts of antioxidant, and 0.5-1.5 parts of light stabilizer; The double-layer functionalized CaO dehydration composite particles, based on 100 parts by weight, include 78-88 parts of CaO core, 5-10 parts of inner functional layer, and 6-12 parts of outer compatibility layer. The particle size of the CaO core is 600-1250 mesh; The inner functional layer is formed of titanate coupling agent and / or aluminate coupling agent, oxidized polyethylene wax and stearate; The outer compatibility layer is formed by maleic anhydride-grafted PP and / or maleic anhydride-grafted POE, wherein the grafting rate of the maleic anhydride-grafted PP and / or maleic anhydride-grafted POE is 0.5-1.5%, and the melt mass flow rate is 50-150 g / 10 min.

2. The composite masterbatch according to claim 1, characterized in that, The inner functional layer comprises 1-3 parts titanate coupling agent and / or aluminate coupling agent, 2-5 parts oxidized polyethylene wax, and 1-3 parts calcium stearate and / or zinc stearate; the outer compatibility layer comprises 6-12 parts maleic anhydride-grafted PP and / or maleic anhydride-grafted POE.

3. The composite masterbatch according to claim 1, characterized in that, The effective calcium oxide content of the CaO core is not less than 85wt%, the moisture content before feeding is not more than 0.5wt%, and the moisture content of the double-layer functionalized CaO dehydration composite particles is not more than 0.3wt%.

4. The composite masterbatch according to claim 1, characterized in that, The heavy metal-free pigment is selected from one or more of titanium dioxide, carbon black, phthalocyanine blue, phthalocyanine green, quinacridone pigment, azo condensation pigment, and anthraquinone pigment, and does not contain lead chromium yellow, molybdenum chromium red, cadmium red, cadmium yellow, or chromate pigment.

5. The composite masterbatch according to claim 1, characterized in that, The inorganic filler is selected from one or more of talc, calcium carbonate, and barium sulfate, wherein the fineness of the talc is 2000-5000 mesh, the fineness of the calcium carbonate is 1250-3000 mesh, and the fineness of the barium sulfate is 2000-5000 mesh.

6. The composite masterbatch according to claim 1, characterized in that, The dispersing lubricant includes at least two of oxidized polyethylene wax, PP wax, EBS and amide wax; the antioxidant includes antioxidant 1010 and antioxidant 168 in a mass ratio of 1:0.5-2; the light stabilizer includes hindered amine light stabilizer and / or benzotriazole UV absorber.

7. The composite masterbatch according to claim 1, characterized in that, The composite masterbatch consists of columnar particles with a length of 2.5-3.5 mm and a diameter of 2.0-3.5 mm. After being sealed and stored at 40°C and 75% RH for 90 days, the composite masterbatch does not exhibit significant agglomeration. Furthermore, when added at 4 wt% to PP resin with a moisture content of 0.08-0.12 wt% for injection molding, it achieves a 100 cm³... 2 The total number of silver threads and bubbles in the sample is ≤5.

8. A method for preparing a composite masterbatch according to any one of claims 1-7, characterized in that, Includes the following steps: Step 1: Dry the injection molding grade PP resin, EVA, and POE at 70-90℃ for 1-3 hours; Dry the heavy metal-free pigments and inorganic fillers at 90-110℃ for 1-2 hours; Step 2: Add CaO, titanate coupling agent and / or aluminate coupling agent, oxidized polyethylene wax and stearate to a high-speed mixer and treat at 90-110℃ and 800-1000r / min for 8-15min to form an inner functional layer on the CaO surface; then graft maleic anhydride onto PP and / or maleic anhydride onto POE and mix at 110-130℃ for 5-10min to obtain bilayer functionalized CaO dehydration composite particles. Step 3: Mix the double-layer functionalized CaO dehydration composite particles, heavy metal-free pigments, inorganic fillers and part of the dispersing lubricant at 70-95℃ and 600-900r / min for 5-8min to obtain the pre-dispersed material; Step 4: Add injection-grade PP resin, EVA, POE, remaining dispersant lubricant, antioxidant, and light stabilizer to the pre-dispersed material, and mix at 75-90℃ for 5-10 minutes to obtain the total mixture; feed the total mixture into a co-rotating twin-screw extruder for melt extrusion. The twin-screw extruder has a length-to-diameter ratio of 36-48, a screw speed of 250-350 r / min, and a vacuum degree of -0.06 to -0.09 MPa in the vacuum exhaust section. The temperature zones of the twin-screw extruder are as follows: Zone 1 160-170℃, Zone 2 175-185℃, Zone 3 185-195℃, Zone 4 195-205℃, Zone 5 200-210℃, Zone 6 200-210℃, Zone 7 195-205℃, and Die Head 200-210℃. Step 5: Cool the extrudate, granulate it, and dry it at 70-80℃ for 2-3 hours to obtain the composite masterbatch.

9. An application of a composite masterbatch, characterized in that, The composite masterbatch according to any one of claims 1-7 is applied to PP injection molded products.

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