Special toughening color master batch for HIPS refrigerator liner and preparation method of special toughening color master batch
By preparing a toughened color masterbatch containing modified titanium dioxide and modified PP resin, the performance problems of HIPS resin under low-temperature brittle fracture and humid heat aging environment were solved, and the high toughness and corrosion resistance of the refrigerator liner were achieved.
Patent Information
- Application Number
- CN202511580418.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-31
- Publication Date
- 2025-12-12
AI Technical Summary
Existing HIPS resins have a high risk of brittle fracture at low temperatures, and the traditional separate toughening and coloring processes result in low processing efficiency and poor performance. Refrigerator liners also lack sufficient toughness and corrosion resistance in humid and hot aging environments.
Toughening masterbatch is prepared by using modified titanium dioxide, modified PP resin, modified lignin, talc, toughening agent, white oil, calcium stearate and EBS and other components through a specific process to improve the toughness, oil corrosion resistance and humid heat aging resistance of HIPS boards.
It significantly improves the toughness, oil corrosion resistance, and damp heat aging resistance of HIPS sheets, thereby enhancing the overall performance of the refrigerator liner.
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Abstract
Description
Technical Field
[0001] This invention relates to a toughening masterbatch for HIPS refrigerator liners and its preparation method, belonging to the field of toughening masterbatch technology. Background Technology
[0002] High-impact polystyrene (HIPS) is an engineering plastic modified by blending polystyrene (PS) with a rubber phase (such as polybutadiene). Its microstructure exhibits an "island" morphology, with rubber particles dispersed in the PS matrix, giving the material high impact resistance. Due to its low cost, ease of processing, and good dimensional stability, HIPS resin has become the preferred material for refrigerator liners, door liners, and other components.
[0003] HIPS resin is prone to brittle fracture in low-temperature environments (such as freezers), necessitating toughening modification. Furthermore, HIPS resin itself is translucent or opaque white, requiring coloring to meet aesthetic requirements. Traditional HIPS material production processes separate toughening modification and coloring: elastomers such as SBS (styrene-butadiene-styrene block copolymer) and SEBS (hydrogenated SBS), or inorganic nanofillers (such as nano-CaCO3), are directly added to the HIPS resin for toughening modification; pigments such as titanium dioxide (TiO2) and carbon black are directly mixed into the HIPS resin, or general-purpose masterbatches are used for coloring. This separate toughening modification and coloring process not only results in low processing efficiency but also often leads to poor compatibility between the separately added toughening materials and pigments (masterbatches) and the HIPS resin, negatively impacting its performance. To address this issue, current methods involve directly adding toughening masterbatches to the HIPS resin to simultaneously perform toughening modification and coloring.
[0004] Toughening masterbatch is a concentrated mixture of toughening agents, pigments, dispersants, carrier resins, and other multifunctional components, which are premixed and granulated. Currently, toughening masterbatch is mainly blended with HIPS resin to prepare HIPS sheets for refrigerator liners. This improves the toughness of the HIPS sheets while coloring them, primarily with white. The amount added is typically 5-8% of the weight of the HIPS resin matrix.
[0005] Refrigerator liners are in constant contact with food, grease, acidic / alkaline cleaning agents, and condensation. They are also exposed to an extremely harsh "humid heat aging" environment. Therefore, refrigerator liners require excellent chemical stability to prevent damage from oil corrosion and humid heat aging that could affect their toughness. However, HIPS itself has limited resistance to oil corrosion and humid heat aging. Long-term use may lead to corrosion or aging, resulting in decreased toughness and even cracking. Therefore, it is necessary to develop a specialized toughening masterbatch for HIPS refrigerator liners that can significantly improve the toughness, oil corrosion resistance, and humid heat aging resistance of HIPS sheet material. Summary of the Invention
[0006] To address the aforementioned problems in the existing technology, the purpose of this invention is to provide a toughening masterbatch for HIPS refrigerator liners and its preparation method.
[0007] To achieve the above objectives, the present invention adopts the following technical solution: A toughening color masterbatch for HIPS refrigerator liners has the following composition and proportions: HIPS (High Impact Polystyrene) resin: 20-30 parts by weight; Modified titanium dioxide: 20-22 parts by weight; Modified PP (polypropylene) resin: 30-40 parts by weight; Modified lignin: 5-8 parts by weight; Talc: 3-5 parts by weight; Toughening agent: 15-25 parts by weight; White oil: 4-6 parts by weight; Calcium stearate: 0.5-1.5 parts by weight; EBS (vinyl bis-stearamide): 0.5-1.5 parts by weight; PE (polyethylene) wax: 0.5-1.5 parts by weight; The modified titanium dioxide is obtained by sequentially coating lanthanum oxide, aluminum oxide, and zirconium dioxide onto the surface of rutile nano-titanium dioxide. Specifically, based on titanium dioxide, the coating amounts of lanthanum oxide are 0.15-0.25 wt%, aluminum oxide is 0.5-1 wt%, and zirconium dioxide is 3.0-5.0 wt%. The modified PP resin is obtained by grafting maleic anhydride onto PP resin. The modified lignin is obtained by grafting lignin with epoxy-terminated polydimethylsiloxane.
[0008] In one embodiment, the toughening agent is SBS (styrene-butadiene-styrene block copolymer) or SEBS (hydrogenated SBS), preferably SEBS.
[0009] One embodiment of the modified titanium dioxide includes the following steps: a) Disperse rutile nano-titanium dioxide in water to obtain a titanium dioxide slurry with a concentration of 240-260 g / L. Heat the titanium dioxide slurry to 55-65℃, add polycarboxylate dispersant, stir for 15-25 minutes, adjust the pH of the slurry to 8.5±0.1 and stabilize it, slowly add 0.1M cerium nitrate aqueous solution, maintaining pH=8.5±0.1 throughout the process. After the addition is complete, keep it at this temperature for 55-65 minutes to obtain a cerium oxide / titanium dioxide composite material slurry. b) Heat the cerium oxide / titanium dioxide composite slurry to 75-85℃, adjust the pH of the slurry to 5.0±0.1 and stabilize it, slowly add 0.3M aluminum nitrate aqueous solution, and maintain pH=5.0±0.1 throughout the process. After the addition is completed, keep it at this temperature for 55-65 minutes to obtain the alumina / cerium oxide / titanium dioxide composite slurry. c) Cool the alumina / cerium oxide / titanium dioxide composite slurry to 55-65℃, adjust the pH of the slurry to 7.0±0.1 and stabilize it, slowly add 0.5M zirconium oxynitrate aqueous solution, maintaining 7.0±0.1 throughout the process. After the addition is complete, keep it at this temperature for 55-65 minutes to obtain the zirconium dioxide / alumina / cerium oxide / titanium dioxide composite slurry. d) The obtained zirconium dioxide / alumina / cerium oxide / titanium dioxide composite slurry was naturally cooled to room temperature, filtered, washed, and dried. The dried powder was placed in an alumina crucible, placed in a muffle furnace, and heated to 500°C in static air at a heating rate of 2°C / min. The mixture was then held at this temperature for 2 hours. After natural cooling, the powder was removed, ground, and the modified titanium dioxide was obtained.
[0010] In a preferred embodiment, in step a), the mass ratio of titanium dioxide slurry to polycarboxylate is (30-40):1.
[0011] One embodiment of the modified PP resin includes the following steps: 100 parts by weight of PP resin, 1-3 parts by weight of maleic anhydride, 0.1-0.3 parts by weight of dicumyl peroxide, 2-5 parts by weight of styrene, and 0.1-0.2 parts by weight of antioxidant 1010 are mixed in a high-speed mixer at room temperature for 5-10 minutes to obtain a mixture. The mixture is then fed into a twin-screw extruder for melt reaction extrusion to obtain modified PP resin.
[0012] In a preferred embodiment, during the melt reaction extrusion process, the temperature of the feeding section is 160-170℃, the temperature of the melting section is 180-190℃, the temperature of the homogenization section is 190-200℃, and the temperature of the die head is 200℃.
[0013] One embodiment of the modified lignin preparation includes the following steps: 1) Dissolve lignin powder in 0.1M NaOH aqueous solution to prepare 4-6wt% lignin alkaline solution. Filter to remove insoluble matter. While stirring, slowly add the filtrate dropwise to dilute hydrochloric acid aqueous solution with pH=2-3 to allow lignin to redefine and precipitate. Filter, wash, dry, grind, and sieve to obtain purified lignin for later use. 2) Add lignin and N-methylpyrrolidone to the reaction vessel, heat to 75-85℃ with stirring, and keep warm and stirring for 1-2 hours to obtain a lignin solution; dissolve epoxy-terminated polysiloxane in N-methylpyrrolidone to obtain an epoxy-terminated polysiloxane solution; cool the lignin solution to 55-65℃, add the catalyst, stir evenly, and then add the epoxy-terminated polysiloxane solution dropwise. After the addition is complete, heat the reaction system to 100-110℃ and keep the reaction for 6-8 hours. After the reaction is complete, cool the reaction solution to room temperature, and slowly pour the reaction solution into a deionized water / methanol mixture with stirring to precipitate the product. Filter, wash, dry, grind, and sieve to obtain modified lignin.
[0014] In a preferred embodiment, in step 1), the mass ratio of dilute hydrochloric acid aqueous solution to lignin alkali solution is (3-5):1.
[0015] In a preferred embodiment, in step 1), the lignin powder used is alkali lignin powder with a weight average molecular weight of 2,000-8,000.
[0016] In a preferred embodiment, in step 1), after filtration, the filter cake is repeatedly washed with deionized water until the filtrate is neutral, and the washed solid is dried in a vacuum drying oven at 50°C.
[0017] In a preferred embodiment, in step 2), the catalyst used is triphenylphosphine, and the amount of catalyst used is 0.5-1.5 wt% of lignin.
[0018] In a preferred embodiment, in step 2), the mass ratio of lignin to epoxy-terminated polysiloxane is 1:(1.5-2.5).
[0019] In a preferred embodiment, in step 2), the molecular weight of the epoxy-terminated polysiloxane is 1000-3000 g / mol.
[0020] In a preferred embodiment, in step 2), after the reaction is completed, the volume ratio of the reaction solution to the deionized water / methanol mixed solution is 1:(8-12), and the volume ratio of deionized water to methanol in the deionized water / methanol mixed solution is 1:1.
[0021] In a preferred embodiment, in step 2), after filtration, the filter cake is repeatedly washed with acetone 3-5 times, and the washed solid is dried in a vacuum drying oven at 50°C.
[0022] The preparation of a toughening masterbatch for HIPS refrigerator liners includes the following steps: The proportions of each component material are added to a high-speed mixer and thoroughly mixed to obtain a uniformly mixed material. The mixture is then fed into a twin-screw extruder for melt reaction extrusion and pelletizing to obtain a toughening masterbatch for HIPS refrigerator liners.
[0023] In one embodiment, during the melt reaction extrusion process, the temperature of the feeding section is 150-170℃, the temperature of the melting section is 170-180℃, the temperature of the homogenization section is 180-195℃, and the temperature of the die head is 200℃.
[0024] Compared with the prior art, the present invention has the following significant advantages: This invention uses HIPS resin and maleic anhydride-grafted modified PP resin as resin carriers, and rutile nano-titanium dioxide coated and modified with lanthanum oxide, alumina and zirconium dioxide as pigments. It also adds lignin grafted and modified with epoxy-terminated polydimethylsiloxane, talc, toughening agent, white oil, calcium stearate, EBS, PE wax and other components. When the toughening masterbatch is added to HIPS sheets, it can effectively improve the toughness, oil corrosion resistance and damp heat aging resistance of HIPS sheets for refrigerator liners, and has great industrial application value. Detailed Implementation
[0025] The technical solution of the present invention will be further described in detail and completely below with reference to the embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or as recommended by the manufacturer. Example 1
[0026] I. Preparation of Modified Titanium Dioxide a) Disperse rutile nano-titanium dioxide in water to obtain a titanium dioxide slurry with a concentration of 250 g / L. Heat the titanium dioxide slurry to 60°C, add polycarboxylate dispersant (slurry:dispersant mass ratio of 35:0.1), stir for 20 minutes, adjust the pH of the slurry to 8.5±0.1 and stabilize it with 2M sodium hydroxide aqueous solution, slowly add 0.1M cerium nitrate aqueous solution (controlling the CeO2 coating amount to 0.2wt% of TiO2, and controlling the dropping rate at 0.5 mL / min), maintain pH=8.5±0.1 throughout the process, and after the addition is completed, keep it at this temperature for 60 minutes to obtain a cerium oxide / titanium dioxide composite material slurry; b) Heat the cerium oxide / titanium dioxide composite slurry to 80℃, adjust the pH of the slurry to 5.0±0.1 and stabilize it with 2M nitric acid aqueous solution, slowly add 0.3M aluminum nitrate aqueous solution (controlling the Al2O3 coating amount to 0.8wt% of TiO2, and controlling the dropping rate to 0.5mL / min), maintain pH=5.0±0.1 throughout the process, and after the addition is completed, keep it at this temperature for 60 minutes to obtain the alumina / cerium oxide / titanium dioxide composite slurry; c) Cool the alumina / cerium oxide / titanium dioxide composite slurry to 60℃, adjust the pH of the slurry to 7.0±0.1 and stabilize it with 2M sodium hydroxide aqueous solution, slowly add 0.5M zirconium oxynitrate aqueous solution (controlling the ZrO2 coating amount to 4wt% of TiO2, and controlling the dropping rate at 0.5mL / min), maintaining 7.0±0.1 throughout the process. After the addition is completed, keep it at this temperature for 60 minutes to obtain the zirconium dioxide / alumina / cerium oxide / titanium dioxide composite slurry; d) The obtained zirconium dioxide / alumina / cerium oxide / titanium dioxide composite slurry was naturally cooled to room temperature, filtered, washed with deionized water, and dried (vacuum dried at 100℃ for 12 hours). The dried powder was placed in an alumina crucible, placed in a muffle furnace, and heated to 500℃ in static air at a heating rate of 2℃ / min. The temperature was then held at this temperature for 2 hours. After natural cooling, the powder was removed, ground in a mortar or vibratory mill, and passed through a 200-mesh sieve to obtain modified titanium dioxide.
[0027] II. Preparation of Modified PP Resin 100 parts by weight of PP resin, 2 parts by weight of maleic anhydride, 0.2 parts by weight of dicumyl peroxide, 3.5 parts by weight of styrene, and 0.15 parts by weight of antioxidant 1010 are mixed in a high-speed mixer at room temperature for 5-10 minutes to obtain a mixture. The mixture is then fed into a twin-screw extruder for melt reaction extrusion. The feeding section temperature is 160-170℃, the melting section temperature is 180-190℃, the homogenization section temperature is 190-200℃, and the die head temperature is 200℃ to obtain modified PP resin.
[0028] III. Preparation of Modified Lignin 1) Dissolve lignin powder (alkali lignin powder with a weight average molecular weight of approximately 5000) in 0.1M NaOH aqueous solution to prepare an approximately 5wt% lignin alkaline solution. Filter the solution with filter paper or a microporous membrane to remove insoluble matter. While stirring, slowly add the filtrate dropwise to a dilute hydrochloric acid aqueous solution with a pH of 2-3. The mass ratio of dilute hydrochloric acid aqueous solution to lignin alkaline solution is 4:1, causing the lignin to redefine and precipitate. Filter the solution, wash with deionized water, dry in a vacuum drying oven at 50℃, grind, and pass through a 100-mesh sieve to obtain purified lignin for later use. 2) Add 10g of lignin and 200ml of [unclear text - possibly a typo, should be 'to'] into the reaction vessel. N-methylpyrrolidone was heated to 80°C with stirring and kept at this temperature for 1-2 hours to obtain a lignin solution. 20g of epoxy-terminated polysiloxane (molecular weight 2000g / mol) was dissolved in 50ml of N-methylpyrrolidone to obtain an epoxy-terminated polysiloxane solution. The lignin solution was cooled to 60°C, and 0.1g of triphenylphosphine catalyst was added and stirred evenly. Then, the epoxy-terminated polysiloxane solution was added dropwise. After the addition was complete, the reaction system was heated to 105°C and kept at this temperature for 7 hours. After the reaction was completed, the reaction solution was cooled to room temperature and slowly poured into a mixed solution of deionized water / methanol with a volume ratio of 1:1 (reaction solution:deionized water / methanol mixed solution volume ratio 1:10) with stirring to precipitate the product. The product was filtered, washed with acetone, dried in a vacuum drying oven at 50°C, ground, and passed through a 200-mesh sieve to obtain modified lignin.
[0029] IV. Preparation of toughening masterbatch 20 parts by weight of HIPS (high-impact polystyrene, specifically HIPS-8265) resin, 20 parts by weight of modified titanium dioxide, 30 parts by weight of modified PP (polypropylene) resin, 5 parts by weight of modified lignin, 3 parts by weight of talc, 15 parts by weight of toughening agent SEBS, 4 parts by weight of white oil, 0.5 parts by weight of calcium stearate, 0.5 parts by weight of EBS (vinyl bis-stearamide), and 0.5 parts by weight of PE (polyethylene) wax are added to a high-speed mixer and thoroughly mixed to obtain a uniformly mixed material. The mixture is then fed into a twin-screw extruder for melt reaction extrusion, pelletizing, with the feeding section temperature at 150-170℃, the melting section temperature at 170-180℃, the homogenization section temperature at 180-195℃, and the die head temperature at 200℃ to obtain a toughening masterbatch for HIPS refrigerator liners. Example 2
[0030] The difference between this embodiment and Embodiment 1 is that: In the preparation of toughening masterbatch, 25 parts by weight of HIPS (high-impact polystyrene) resin, 21 parts by weight of modified titanium dioxide, 35 parts by weight of modified PP (polypropylene) resin, 6.5 parts by weight of modified lignin, 4 parts by weight of talc, 20 parts by weight of toughening agent SEBS, 5 parts by weight of white oil, 1 part by weight of calcium stearate, 1 part by weight of EBS (vinyl bis-stearamide), and 1 part by weight of PE (polyethylene) wax are added to a high-speed mixer and thoroughly mixed to obtain a uniformly mixed material. Example 3
[0031] The difference between this embodiment and Embodiment 1 is that: The toughening masterbatch is prepared by adding 30 parts by weight of HIPS (high-impact polystyrene) resin, 22 parts by weight of modified titanium dioxide, 40 parts by weight of modified PP (polypropylene) resin, 8 parts by weight of modified lignin, 5 parts by weight of talc, 25 parts by weight of toughening agent SEBS, 6 parts by weight of white oil, 1.5 parts by weight of calcium stearate, 1.5 parts by weight of EBS (vinyl bis-stearamide), and 1.5 parts by weight of PE (polyethylene) wax into a high-speed mixer and mixing thoroughly to obtain a uniformly mixed material.
[0032] Comparative Example 1 The difference between this comparative example and Example 1 is as follows: In the toughening masterbatch formulation, ordinary rutile nano-titanium dioxide is used instead of the self-made modified titanium dioxide (rutile nano-titanium dioxide coated and modified with lanthanum oxide, aluminum oxide and zirconium dioxide) in Example 1.
[0033] Comparative Example 2 The difference between this comparative example and Example 1 is as follows: In the toughening masterbatch formulation, ordinary PP resin is used instead of the self-made modified PP resin (maleic anhydride grafted modified PP resin) in Example 1.
[0034] Comparative Example 3 The difference between this comparative example and Example 1 is as follows: In the toughening masterbatch formulation, ordinary rutile nano-titanium dioxide is used instead of the self-made modified titanium dioxide (rutile nano-titanium dioxide coated and modified with lanthanum oxide, alumina and zirconium dioxide) in Example 1, ordinary PP resin is used instead of the self-made modified PP resin (maleic anhydride grafted modified PP resin) in Example 1, and ordinary lignin is used instead of the self-made modified lignin (epoxy-terminated polydimethylsiloxane grafted modified lignin) in Example 1.
[0035] Comparative Example 4 The difference between this comparative example and Example 1 is as follows: In the toughening masterbatch formulation, ordinary rutile nano-titanium dioxide is used instead of the self-made modified titanium dioxide (rutile nano-titanium dioxide coated and modified with lanthanum oxide, alumina and zirconium dioxide) in Example 1, and ordinary PP resin is used instead of the self-made modified PP resin (maleic anhydride grafted modified PP resin) in Example 1, and it does not contain modified lignin.
[0036] Performance testing: Five parts by weight of the toughening masterbatch prepared in the examples and comparative examples were blended with 100 parts by weight of HIPS-8265 resin to prepare corresponding HIPS sheets for refrigerator liners. The performance of the prepared HIPS sheets was tested to investigate the effect of the toughening masterbatch on the HIPS sheets.
[0037] 1) Toughness test: The tensile strength (test method: GB / T1040, condition: 50 mm / min, unit: MPa), elongation at break (test method: GB / T1040, condition: 50 mm / min, unit: %), flexural strength (test method: GB / T9341, condition: 2 mm / min, unit: MPa), flexural modulus (test method: GB / T9341, condition: 2 mm / min, unit: MPa), and impact properties (test method: GB / T1843, unit: KJ / m) of HIPS sheets without toughening masterbatch and HIPS sheets with 5% toughening masterbatch are tested. 2 The test was conducted, and the results are shown in Table 1.
[0038] Table 1 Toughness test data of HIPS sheets
[0039] As shown in Table 1, adding toughening masterbatch to HIPS can effectively improve the toughness of HIPS sheets. Furthermore, under the same conditions, the toughening effect of the masterbatch in the examples on HIPS is superior to that of the comparative example. This may be because: The toughening masterbatch used in this embodiment employs modified titanium dioxide coated with lanthanum oxide, alumina, and zirconium dioxide. Compared to ordinary titanium dioxide, it exhibits superior dispersibility and interfacial bonding in resin, effectively transferring stress and preventing crack propagation. The PP resin used is modified PP resin grafted with maleic anhydride, which, compared to ordinary PP resin, demonstrates excellent compatibility with HIPS and forms a stronger interfacial bond. The modified lignin grafted with epoxy-terminated polysiloxane possesses flexible segments that effectively absorb impact energy. When these components are combined with HIPS resin, talc, toughening agent, white oil, and other components, they exhibit a significant synergistic effect, thereby significantly enhancing the toughness of HIPS sheets.
[0040] 2) Oil corrosion resistance test HIPS boards prepared by adding color masterbatches from Examples 1-3 and Comparative Examples 1-4 respectively were coated with a corrosive medium at room temperature and left for 24 hours. The corrosion medium was a mixture of oleic acid and cottonseed oil in a volume ratio of 1:1. The oil corrosion resistance of the HIPS boards was determined by the changes in tensile strength and elongation at break before and after coating with the corrosion medium. The test results are shown in Table 2.
[0041] Table 2. Oil corrosion resistance test data of HIPS sheets
[0042] As shown in Table 2, the HIPS sheets with the toughened masterbatch prepared in the examples showed almost no change in tensile strength and elongation at break after being immersed in edible oil for 24 hours. This indicates that the HIPS sheets with the toughened masterbatch prepared in the examples have excellent oil corrosion resistance. Furthermore, under the same conditions, the oil corrosion resistance of the HIPS sheets with the toughened masterbatch prepared in the examples is better than that of the HIPS sheets with the toughened masterbatch prepared in the comparative example. This may be because: The toughening masterbatch in the examples uses modified titanium dioxide coated with lanthanum oxide, alumina, and zirconium dioxide, and modified lignin grafted with epoxy-terminated polysiloxane. Both have oleophobic and dense surface structures, effectively blocking oil molecule penetration, and the modified lignin has excellent chemical corrosion resistance. In addition, the modified PP resin grafted with maleic anhydride used in the examples has grafted polar groups on its surface that enhance the interfacial bonding with inorganic fillers, reducing the diffusion path of oil molecules. When the above components are compounded with HIPS resin, talc, toughening agent, white oil, and other components, they have a significant synergistic effect, thereby significantly enhancing the oil corrosion resistance of HIPS boards.
[0043] 3) Resistance to damp heat aging test HIPS boards prepared with color masterbatches from Examples 1-3 and Comparative Examples 1-4 were subjected to damp heat aging tests using a constant temperature and humidity chamber. The test conditions were: test temperature: 60℃ ± 2℃; test humidity: 90% RH ± 5%; test duration: 1000 hours. The damp heat aging resistance of the HIPS boards was determined by the changes in color difference (ΔE, measured by a colorimeter), tensile strength, and elongation at break. The test results are shown in Table 3.
[0044] Table 3. Test data on the resistance to damp heat aging of HIPS boards.
[0045] As shown in Table 3, after the damp heat aging test, the HIPS sheets with the toughened masterbatch prepared in the examples showed very slight changes in color difference, tensile strength, and elongation at break. This indicates that the HIPS sheets with the toughened masterbatch prepared in the examples have excellent resistance to damp heat aging. Furthermore, under the same conditions, the HIPS sheets with the toughened masterbatch prepared in the examples have better resistance to damp heat aging than the HIPS sheets with the toughened masterbatch prepared in the comparative example. This may be because: The toughening masterbatch used in the examples is modified titanium dioxide coated with lanthanum oxide, alumina, and zirconium dioxide. The lanthanum oxide and zirconium dioxide in the modified titanium dioxide have ultraviolet shielding and antioxidant functions, which can delay photo-oxidative aging. The modified lignin grafted with epoxy-terminated polysiloxane has excellent heat resistance and hydrophobicity, which can reduce moisture intrusion. The modified titanium dioxide, modified lignin, and other components such as HIPS resin, modified PP resin, talc, toughening agent, and white oil have a significant synergistic effect, which can form a dense coating layer and interface structure, thereby effectively blocking the penetration of water vapor and oxygen, delaying aging and degradation, and thus significantly enhancing the resistance of HIPS boards to humid heat aging.
[0046] In summary, the HIPS sheets prepared with the color masterbatch of Examples 1-3 of the present invention have better toughness, oil corrosion resistance and damp heat aging resistance compared with the HIPS sheets prepared with the color masterbatch of Comparative Examples 1-4. It can be seen that when the toughening color masterbatch of Examples 1-3 of the present invention is used to prepare HIPS sheets for refrigerator liners, it not only significantly improves the toughness of the HIPS sheets, but also significantly improves the oil corrosion resistance and damp heat aging resistance of the HIPS sheets.
[0047] Finally, it should be noted that the above are only some preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention shall fall within the scope of protection of the present invention.
Claims
1. A toughening color masterbatch specifically for HIPS refrigerator liners, characterized in that, It has the following composition and proportions: HIPS resin: 20-30 parts by weight; Modified titanium dioxide: 20-22 parts by weight; Modified PP resin: 30-40 parts by weight; Modified lignin: 5-8 parts by weight; Talc: 3-5 parts by weight; Toughening agent: 15-25 parts by weight; White oil: 4-6 parts by weight; Calcium stearate: 0.5-1.5 parts by weight; EBS: 0.5-1.5 parts by weight; PE wax: 0.5-1.5 parts by weight; The modified titanium dioxide is obtained by sequentially coating lanthanum oxide, aluminum oxide, and zirconium dioxide onto the surface of rutile nano-titanium dioxide. Specifically, based on titanium dioxide, the coating amounts of lanthanum oxide are 0.15-0.25 wt%, aluminum oxide is 0.5-1 wt%, and zirconium dioxide is 3.0-5.0 wt%. The modified PP resin is obtained by grafting maleic anhydride onto PP resin. The modified lignin is obtained by grafting lignin with epoxy-terminated polydimethylsiloxane.
2. The toughening masterbatch for HIPS refrigerator liners according to claim 1, characterized in that: The toughening agent is SBS or SEBS.
3. The toughening masterbatch for HIPS refrigerator liners according to claim 1, characterized in that, The preparation of the modified titanium dioxide includes the following steps: a) Disperse rutile nano-titanium dioxide in water to obtain a titanium dioxide slurry with a concentration of 240-260 g / L. Heat the titanium dioxide slurry to 55-65℃, add polycarboxylate dispersant, stir for 15-25 minutes, adjust the pH of the slurry to 8.5±0.1 and stabilize it, slowly add 0.1M cerium nitrate aqueous solution, maintaining pH=8.5±0.1 throughout the process. After the addition is complete, keep it at this temperature for 55-65 minutes to obtain a cerium oxide / titanium dioxide composite material slurry. b) Heat the cerium oxide / titanium dioxide composite slurry to 75-85℃, adjust the pH of the slurry to 5.0±0.1 and stabilize it, slowly add 0.3M aluminum nitrate aqueous solution, and maintain pH=5.0±0.1 throughout the process. After the addition is completed, keep it at this temperature for 55-65 minutes to obtain the alumina / cerium oxide / titanium dioxide composite slurry. c) Cool the alumina / cerium oxide / titanium dioxide composite slurry to 55-65℃, adjust the pH of the slurry to 7.0±0.1 and stabilize it, slowly add 0.5M zirconium oxynitrate aqueous solution, maintaining 7.0±0.1 throughout the process. After the addition is complete, keep it at this temperature for 55-65 minutes to obtain the zirconium dioxide / alumina / cerium oxide / titanium dioxide composite slurry. d) The obtained zirconium dioxide / alumina / cerium oxide / titanium dioxide composite slurry was naturally cooled to room temperature, filtered, washed, and dried. The dried powder was placed in an alumina crucible, placed in a muffle furnace, and heated to 500°C in static air at a heating rate of 2°C / min. The mixture was then held at this temperature for 2 hours. After natural cooling, the powder was removed, ground, and the modified titanium dioxide was obtained.
4. The toughening masterbatch for HIPS refrigerator liners according to claim 3, characterized in that, In step a), the mass ratio of titanium dioxide slurry to polycarboxylate is (30-40):
1.
5. The toughening masterbatch for HIPS refrigerator liners according to claim 1, characterized in that, The preparation of the modified PP resin includes the following steps: 100 parts by weight of PP resin, 1-3 parts by weight of maleic anhydride, 0.1-0.3 parts by weight of dicumyl peroxide, 2-5 parts by weight of styrene, and 0.1-0.2 parts by weight of antioxidant 1010 are mixed in a high-speed mixer at room temperature for 5-10 minutes to obtain a mixture. The mixture is then fed into a twin-screw extruder for melt reaction extrusion to obtain modified PP resin.
6. The toughening masterbatch for HIPS refrigerator liners according to claim 1, characterized in that, The preparation of the modified lignin includes the following steps: 1) Dissolve lignin powder in 0.1M NaOH aqueous solution to prepare 4-6wt% lignin alkaline solution. Filter to remove insoluble matter. While stirring, slowly add the filtrate dropwise to dilute hydrochloric acid aqueous solution with pH=2-3 to allow lignin to redefine and precipitate. Filter, wash, dry, grind, and sieve to obtain purified lignin for later use. 2) Add lignin and N-methylpyrrolidone to the reaction vessel, heat to 75-85℃ with stirring, and keep warm and stirring for 1-2 hours to obtain a lignin solution; dissolve epoxy-terminated polysiloxane in N-methylpyrrolidone to obtain an epoxy-terminated polysiloxane solution; cool the lignin solution to 55-65℃, add the catalyst, stir evenly, and then add the epoxy-terminated polysiloxane solution dropwise. After the addition is complete, heat the reaction system to 100-110℃ and keep the reaction for 6-8 hours. After the reaction is complete, cool the reaction solution to room temperature, and slowly pour the reaction solution into a deionized water / methanol mixture with stirring to precipitate the product. Filter, wash, dry, grind, and sieve to obtain modified lignin.
7. The toughening masterbatch for HIPS refrigerator liners according to claim 6, characterized in that, In step 1), the mass ratio of dilute hydrochloric acid aqueous solution to lignin alkali solution is (3-5):
1.
8. The toughening masterbatch for HIPS refrigerator liners according to claim 6, characterized in that, In step 2), the catalyst used is triphenylphosphine, and the amount of catalyst used is 0.5-1.5 wt% of lignin.
9. The toughening masterbatch for HIPS refrigerator liners according to claim 6, characterized in that, In step 2), the mass ratio of lignin to epoxy-terminated polysiloxane is 1:(1.5-2.5).
10. A method for preparing the toughening masterbatch for HIPS refrigerator liners as described in claim 1, characterized in that, Includes the following steps: The proportions of each component material are added to a high-speed mixer and thoroughly mixed to obtain a uniformly mixed material. The mixture is then fed into a twin-screw extruder for melt reaction extrusion and pelletizing to obtain a toughening masterbatch for HIPS refrigerator liners.