A high-whiteness, low-titanium dioxide content, high-efficiency light-blocking masterbatch and its preparation method

Abstract

The present invention discloses a high-whiteness, low-titanium dioxide content, and efficient light-blocking masterbatch and a preparation method thereof. Styrene-methyl methacrylate copolymer resin is selected as a base carrier. The styrene-methyl methacrylate copolymer resin is blended with polyester plastic to form an uneven and irregular interface during the stretching process of preform injection and bottle blowing, which scatters, refracts, and reflects light, reduces the transmittance of light, and thus achieves a synergistic light-blocking effect. To maximize the interface effect, in addition to the styrene-methyl methacrylate copolymer, a high polymer that also has a certain interface effect with the polyester plastic is added. At the same time, a compatibilizer or a grafting agent is added to improve the compatibility of the polymer and the polyester plastic. Under the same addition ratio, the light-blocking masterbatch disclosed by the present invention has higher whiteness and light-blocking properties, lower titanium dioxide content, significantly reduced energy consumption during preform injection and bottle blowing, and better physical properties of the bottle body, better toughness, and lower cost.

Description

Technical Field

[0001] The invention relates to the technical field of plastic coloring, and in particular to a high-efficiency light-blocking masterbatch with high whiteness and low titanium dioxide content and a preparation method thereof. Background Art

[0002] When packaging dairy products, including milk drinks and yogurt, light protection is a key consideration. Light has a significant impact on dairy products. It destroys nutrients in milk and stimulates unstable substances in the milk to produce free radicals, accelerating oxidation and deterioration. Furthermore, many nutrients in milk, such as vitamin A, vitamin B2 (riboflavin), vitamin D, and amino acids, are lost due to light exposure. The most common reaction to milk under light conditions is the light-induced oxidation of cysteine, which produces sulfides such as mercaptans and dimethyl sulfide, all of which can severely affect the taste and nutritional value of milk.

[0003] Currently, many dairy products are packaged and sold through a cold chain. However, factors such as a short shelf life, high storage and transportation costs, and a narrow sales radius have severely impacted sales reach and sales. Some dairy companies are using Tetra Pak paper-plastic packaging for ambient temperature sales after high-temperature sterilization, extending the shelf life to six months or even nine months and expanding sales nationwide. However, Tetra Pak packaging presents significant challenges, including high equipment investment, a single packaging format, and difficulty resealing and recycling once opened. Ambient temperature plastic packaging is increasingly favored by dairy companies and consumers, with polyester plastic packaging being the most popular. Polyester packaging offers unique advantages, including a wide range of bottle designs, high production efficiency, and universal injection molding equipment, avoiding duplication of investment. However, polyester plastic packaging exhibits high light transmittance, which conflicts with the high light-blocking requirements of dairy products. Therefore, the addition of high-light-blocking masterbatch (ideally with a light-blocking rating of 99.9% or higher) is necessary to enhance the light-blocking properties of polyester bottles, thereby protecting the quality of the dairy products and extending their shelf life.

[0004] my country's annual dairy product output is 30.546 million tons (National Bureau of Statistics, full-year data for 2023). In such a huge dairy market, cold chain transportation and Tetra Pak paper and plastic packaging can no longer meet the needs of market expansion and consumers' growing pursuit of packaging diversity, aesthetics and high quality. Room temperature plastic packaging has emerged, and high light-blocking additives for plastic packaging have also emerged.

[0005] The mainstream high-light-blocking masterbatches currently on the market are primarily based on polyester materials, combined with other tougher polymers such as polypropylene (PP), polyethylene (PE), and polystyrene (PS). These materials are not only highly compatible with polyester plastics but also offer improved compatibility with inorganic materials like titanium dioxide, thereby enhancing light-blocking properties. They also improve the toughness and impact resistance of bottles when high levels of light-blocking masterbatches are added, preventing problems such as bottles bursting when dropped. These traditional high-light-blocking masterbatches primarily contain titanium dioxide as the light-blocking component, with a content of up to 60% to 70% in the formula. Because titanium dioxide offers advantages such as high whiteness and excellent hiding power, inorganic materials with even greater hiding power, such as carbon black, are sometimes added to enhance hiding. However, these traditional high-light-blocking masterbatches suffer from low whiteness, high titanium dioxide content, high energy consumption for blowing, and a high rate of bottle explosions. The gray appearance of the bottle lowers the texture and aesthetics of the packaging. The outside of the bottle usually needs to be completely wrapped with a label to cover the quality defects of the appearance, but the bottle mouth will still be exposed after opening, affecting the consumer's sensory experience. Regarding titanium dioxide, on May 6, 2021, the European Food Safety Authority (EFSA) announced that the genotoxicity of titanium dioxide (TiO2; CAS13463-67-7) could not be ruled out, so the EU announced a ban on titanium dioxide as a food additive. Although on November 23, 2022, the European Court of Justice recommended the abolition of the classification and labeling of titanium dioxide as a carcinogen when inhaled in certain powder forms, which means that the EU has relaxed the application of titanium dioxide in industries such as food and coatings at this stage, detailed guidelines for the inhalation and packaging applications of titanium dioxide may still be issued in the future. Therefore, the content or addition ratio of titanium dioxide used in food and beverage packaging should be controlled as much as possible to minimize the risk of its migration into food and beverages.

[0006] In summary, there is a strong demand in the market for high-light-blocking masterbatches with high whiteness, low titanium dioxide content, energy saving and high efficiency. Summary of the Invention

[0007] The purpose of the present invention is to provide a high-whiteness, low-titanium dioxide content, high-efficiency light-blocking masterbatch and a preparation method thereof, so as to solve the problem of excessively high titanium dioxide content in the high-light-blocking masterbatch.

[0008] In order to achieve the above-mentioned object of the invention, the present invention provides a high-whiteness and low-titanium dioxide content high-efficiency light-blocking masterbatch, comprising:

[0009] Styrene-methyl methacrylate copolymer resin, thermoplastic polymer material and titanium dioxide;

[0010] The mass content of the styrene-methyl methacrylate copolymer resin is 5% to 60%, the mass content of the thermoplastic high polymer material is 3% to 30%, and the mass content of the titanium dioxide is 10% to 60%;

[0011] The thermoplastic high polymer material includes one or more of thermoplastic elastomer TPE, polymethyl methacrylate PMMA, poly-4-methyl-1-pentene PMP, cycloolefin copolymer COC, thermoplastic polyester elastomer TPEE or aliphatic polyketone resin POK.

[0012] Optionally, it further comprises a high-hiding inorganic substance with a mass content of 1% to 30%, wherein the high-hiding inorganic substance comprises one or more of calcined kaolin, calcite powder, silica powder, zinc oxide, barium sulfate, zinc sulfide or calcium carbonate.

[0013] Optionally, the invention further comprises a metal pigment with a mass content of 0.01% to 5%, wherein the metal pigment comprises a metal aluminum pigment or a bronze pigment.

[0014] Optionally, the composition further comprises a compatibilizer having a mass content of 0.01% to 5%, wherein the compatibilizer comprises one or more of POE-g-GMA, PP-g-MAH, PE-g-MAH or POE-g-MAH.

[0015] Optionally, the composition further comprises an auxiliary agent with a mass content of 0.01% to 10%, wherein the auxiliary agent comprises one or more of a dispersing lubricant, an antioxidant, a reheat absorber, a light stabilizer or an antistatic agent.

[0016] Optionally, the composition further comprises an organic dye having a mass content of 0.01% to 10%.

[0017] The present invention also provides a method for preparing a high-efficiency light-blocking masterbatch with high whiteness and low titanium dioxide content, comprising:

[0018] Disperse the formulated materials into a uniform mixture and granulate;

[0019] The granulation process comprises:

[0020] The mixture is heated to the plasticizing temperature and vacuumed;

[0021] Passing the plasticized material through an extruder to form a continuous molten extrudate;

[0022] Cooling to form solid particles;

[0023] The solid particles are cut into predetermined sizes and then screened for rejection.

[0024] Optionally, during the granulation process, the feed temperature section is set to 280°C to 290°C, the equilibrium temperature section is set to 270°C to 280°C, and the discharge temperature section is set to 260°C to 270°C.

[0025] Optionally, during the granulation process, the vacuum degree of the vacuum pumping section is controlled to be 0.6-0.8 MPa; the temperature of the extrusion section is 260° C.; and the speed of the pelletizer is 800-900 r / min.

[0026] Compared with the existing technology, the advantages and positive effects of the present invention are: the present invention provides a high-light-blocking masterbatch with high whiteness, low titanium dioxide content and energy saving and consumption reduction. Compared with traditional high-light-blocking masterbatch, at the same addition ratio, it has higher whiteness and light-blocking properties, lower titanium dioxide content, and significantly reduced energy consumption for injection molding and bottle blowing. In addition, the physical properties of the bottle body are better, the toughness effect is better, and the cost is lower. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the molecular structure of styrene-methylmethacrylate copolymer (MS) in an embodiment of the present invention;

[0028] Figure 2 IR spectrum of MS in the embodiment of the present invention;

[0029] Figure 3 Schematic diagram of the formation process of MS resin in an embodiment of the present invention;

[0030] Figure 4 This is a comparison curve of hiding power of different pigments;

[0031] Figure 5 Schematic diagram of the interfacial effect and microcellular structure of MS and polyester blends in an embodiment of the present invention;

[0032] Figure 6 Schematic diagram of the interfacial effect and microcellular structure of the blend of MS, polyester, titanium dioxide and other inorganic substances in the embodiment of the present invention;

[0033] Figure 7 This is a bar graph of the light-blocking properties of the compositions of groups F2-F7 in the examples of the present invention;

[0034] Figure 8 This is a bar graph of the light-blocking properties of the compositions of groups F8-F15 in the examples of the present invention;

[0035] Figure 9 This is a bar graph of the light-blocking properties of the compositions of groups F16 to F25 in the embodiments of the present invention;

[0036] Figure 10This is a scanning electron microscope image of the composition of group F23 in the embodiment of the present invention;

[0037] Figure 11 This is a bar chart comparing the whiteness of Experimental Examples 1-9 and the traditional light-blocking masterbatch in the embodiments of the present invention;

[0038] Figure 12 Schematic diagram comparing the light-blocking performance of Experimental Examples 1-9 and traditional light-blocking masterbatches in the embodiments of the present invention;

[0039] Figure 13 Schematic diagram of vertical loading and pressing of a conventional empty bottle of light-blocking masterbatch according to an embodiment of the present invention;

[0040] Figure 14 Schematic diagram of vertical pressure loading of empty bottles in Experimental Example 2 of the embodiment of the present invention. DETAILED DESCRIPTION

[0041] The present invention will be described in more detail below with reference to the accompanying drawings, in which preferred embodiments of the present invention are shown. It should be understood that those skilled in the art may modify the present invention described herein while still achieving the advantageous effects of the present invention. Therefore, the following description should be understood as a general guide for those skilled in the art and not as a limitation of the present invention.

[0042] The following paragraphs describe the present invention in more detail by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the drawings are greatly simplified and not to exact scale, and are provided solely for the purpose of assisting in the description of the embodiments of the present invention.

[0043] Example 1

[0044] This embodiment provides a high-whiteness, low-titanium dioxide content, high-efficiency light-blocking masterbatch, comprising: styrene-methyl methacrylate copolymer resin, a thermoplastic high polymer material, and titanium dioxide; the mass content of the styrene-methyl methacrylate copolymer resin is 5% to 60%, the mass content of the thermoplastic high polymer material is 3% to 30%, and the mass content of the titanium dioxide is 10% to 60%.

[0045] The mass content of the styrene-methyl methacrylate copolymer resin can specifically be 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55% or 60%.

[0046] The mass content of the titanium dioxide can specifically be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55% or 60%.

[0047] The mass content of the thermoplastic high polymer material can specifically be 5%, 10%, 15%, 17%, 18%, 19%, 20%, 22%, 24%, 25%, 26%, 28%, 29% or 30%.

[0048] Styrene-methylmethacrylate copolymer resin (MS), the molecular structure and infrared spectrum of MS resin can be found in Figure 1 - Figure 2 .

[0049] Styrene-methyl methacrylate copolymer (MS) resin combines the excellent processing fluidity and low hygroscopicity of polystyrene with the weather resistance and excellent optical properties of methyl methacrylate. With a refractive index of 1.56 and transparency similar to that of polystyrene, it is a transparent, non-toxic thermoplastic. MS resin boasts higher impact strength than polystyrene and a heat deflection temperature similar to that of methyl methacrylate, resulting in a range of excellent properties for an optical-grade material.

[0050] For the formation process of styrene-methyl methacrylate copolymer (MS) resin, please refer to Figure 3 .

[0051] Styrene-methyl methacrylate copolymer (MS) resin is a silyl-terminated polyether prepolymer, primarily produced by copolymerizing MMA monomers with styrene. It exhibits excellent optical properties and, thanks to its non-toxicity, good fluidity, weather resistance, and low hygroscopicity, is widely used in optical displays, daily necessities, and medical applications. my country's MS production capacity is gradually increasing, with several companies, such as Suzhou Shuangxiang Optics, Yantai Wanhua, Jiangsu Saibaolong, Jiangsu Xinpu, and Henan Duonai, entering the market. This has led to a gradual increase in MS supply and a return to a more rational price.

[0052] The reason why the present invention chooses styrene-methyl methacrylate copolymer as the basic carrier is mainly because it forms an uneven and irregular interface effect during the process of blowing and stretching after being blended with polyester plastic and injected into the embryo, which causes light to be scattered, refracted and reflected, reducing the transmittance of light, thereby achieving a synergistic light-blocking effect.

[0053] Interfacial effects refer to changes in physical, chemical, and biological properties at a material's surface or interface caused by the unique properties of the surface or interface. These changes can affect the material's performance and behavior. This application primarily focuses on the optical impact of interfacial effects: light is reflected, refracted, and scattered at the surface or interface of two materials, affecting the material's light transmittance or hiding power.

[0054] At the same polymer addition ratio, in order to maximize the interfacial effect, in addition to styrene-methyl methacrylate copolymer, one or more polymer materials that also have certain interfacial effects with polyester plastics are added, such as thermoplastic elastomer TPE (Thermoplastic Elastomer), polymethyl methacrylate PMMA (Polymethyl Methacrylate), poly-4-methyl-1-pentene PMP (Poly(4-methyl-1-pentene)), cycloolefin copolymer COC, thermoplastic polyester elastomer TPEE (Thermoplastic Polyester Elastomer) or aliphatic polyketone POK resin, so that the interfacial effects produced by several different polymers are superimposed and enhanced.

[0055] Experiments have shown that by adding another suitable polymer in an appropriate ratio, the light-blocking performance and injection molding blow molding processing performance can be improved to a certain extent, and the overall cost can also be reduced.

[0056] Applicants have discovered that when polymers such as styrene-methyl methacrylate copolymer (MS), thermoplastic elastomer (TPE), polymethyl methacrylate (PMMA), poly-4-methyl-1-pentene (PMP), cycloolefin copolymer (COC), thermoplastic polyester elastomer (TPEE), and aliphatic polyketone (POK) resins are blended with polyester plastics, they not only produce a certain degree of interfacial effect but also form numerous tiny micropores. This is because blending two or more polymers with different crystalline properties changes their crystal shape and reduces their crystallinity. This reduced crystallinity increases CO2 solubility, resulting in numerous tiny micropores. These tiny micropore structures can also improve light-blocking properties or hiding power to a certain extent, as light-blocking properties depend not only on the concentration of inorganic pigments such as titanium dioxide but also on the refractive index difference between the pigment and the medium. The greater the difference, the better the light-blocking properties. By keeping the refractive index of the pigment unchanged and reducing the refractive index of the medium, the light-blocking properties of the bottle can be improved. Introducing micropores into plastic sheets or bottles can lower the medium's refractive index. The more pores introduced, the lower the refractive index of the porous medium. The greater the refractive index difference between the pigment and the medium, the better the bottle's light-blocking properties. However, excessive micropore density can affect key physical properties like toughness and strength, potentially leading to rupture and other issues, so a careful balance is crucial.

[0057] The light-blocking property of a pigment, also known as its hiding power, is determined by the difference in refractive index between the pigment and the surrounding medium or base. When the refractive indices of the pigment and base are equal, the pigment is transparent. When the pigment's refractive index is greater than that of the base, the pigment hides the light. The greater the difference, the greater the hiding power or light-blocking property. See Table 1 for refractive index data for several common substances.

[0058] Table 1

[0059]

[0060] White pigments are mainly scattered, and the hiding power generated by scattering is mainly related to three factors: the Lorentz factor, pigment concentration, and pigment particle size. The Lorentz factor reflects the refractive index relationship between the pigment and the base material, as shown in the following formula:

[0061] L=(n p 2 -n b 2 ) / (n p 2 +2n b 2 );

[0062] Where L is the Lorentz factor, n p is the refractive index of the pigment, n b is the refractive index of the film-forming material.

[0063] The light blocking property or hiding power is proportional to the square of L, which means that the greater the refractive index difference between the pigment and the base material, the higher the light blocking property or hiding power.

[0064] In order to verify the light-blocking properties of different inorganic substances in PET polyester, PET polyester (Wankai WK-801) was first ground into a 200-mesh fine powder, and then mixed with titanium dioxide (Chemours R-902), calcium carbonate (Omya OM2T), zinc oxide (Lutai LT-AH01), and calcined kaolin (BASF Translink37) at a ratio of 95% (PET polyester): 5% (inorganic pigment). The mixture was injection-molded into sheets with the same thickness (0.3 mm) and tested for different light transmittances. The comparison curves are shown in the figure. Figure 4 shown.

[0065] pass Figure 4 It can be seen that rutile titanium dioxide and polyester PET substrate have a higher refractive index, and thus have higher hiding power or light blocking properties.

[0066] Please refer to Figure 5 - Figure 6 In the two electron microscope photos, Figure 5 This is an electron microscope image of a blend of styrene-methyl methacrylate copolymer and polyester resin. Figure 6 This is a picture of a blend of styrene-methyl methacrylate copolymer, polyester, titanium dioxide and other inorganic substances. The interfacial effect and micro-bubble structure produced can be clearly seen.

[0067] In order to observe the superimposed light-blocking effect of polyester PET and the resin with an interface effect of the present application, the mixture of the base resin part of Experimental Example 7 of the present application was used as the analysis sample. Its composition and proportion are shown in Table 2 below. The analysis sample was dry-mixed and injection-molded and then blown into a bottle. Thin slices of a certain thickness were cut and scanned by an electron microscope (the electron microscope was CIQTEK SEM5000). Figure 5 shown.

[0068] Table 2

[0069]

[0070]

[0071] The formula raw material information and ratio of Experimental Example 7 are summarized in Table 3. After drying, the light-blocking masterbatch obtained in Experimental Example 7 was blended with 90% dried polyester PET (Zhejiang Wankai WK-801) at a ratio of 10%, and the mixture was subjected to electron microscope scanning to obtain electron microscope photos as shown in FIG. Figure 6 shown.

[0072] Table 3

[0073]

[0074] The main application direction of the present invention application is polyester resin, which includes polyethylene terephthalate (PET), PET copolymers, polybutylene terephthalate (PBT), PBT copolymers, polyethylene naphthalate (PEN), amorphous copolyester (PETG) and polyarylate (PAR), polylactic acid (PLA), polypropylene terephthalate (PTT), polyethylene furandicarboxylate (PEF), polycyclohexane dimethyl terephthalate (PCT), PCT copolymers, polycaprolactone (PCL), polyhydroxyalkanoate (PHA) and PHA copolymers, etc. According to the universality of the final application, bottle-grade polyester PET is usually the main application. Bottle-grade PET polyester is generally made by condensation of terephthalic acid (PTA) and ethylene glycol (EG) under the action of catalysts such as antimony or titanium metal.

[0075] Seven mixture formulations were prepared using polyester (PET) as the base, along with styrene-methyl methacrylate copolymer (MS), thermoplastic elastomer (TPE), polymethyl methacrylate (PMMA), polymethylpentene (PMP), cycloolefin copolymer (COC), and aliphatic polyketone (POK). All resins were purchased commercially: Zhejiang Wankai WK-801 bottle-grade polyester chips with an intrinsic viscosity of 0.8 dL / g; TX400S from Denki Chemical; GLS G2712 from GLS; TPX RT180 from Mitsui Chemicals; IH830 from LG Chem; 6013S from Polyplastics; and M630 from Hyosung.

[0076] Seven mixture formulas were prepared according to the following ratios as shown in Table 4, where F1 in Table 4 is 100% PET resin, and F2-F7 each contains 98% PET polyester with 2% of a different resin added. These seven single or mixed materials were used to make panels to compare their light transmittance properties.

[0077] Table 4

[0078] F1 F2 F3 F4 F5 F6 F7 PET 100 98 98 98 98 98 98 MS 2 TPE 2 PMP 2 COC 2 PMMA 2 POK 2 100 100 100 100 100 100 100

[0079] For the above seven mixture formulas, preforms were injected and blown into bottles, and slices of about 2.5 cm × 5 cm and 2 mm thick were cut and tested using a spectrophotometer. To ensure the accuracy of the test data, a spectrophotometer with an integrating sphere was used in this embodiment.

[0080] The instrument used for detection in this embodiment is a Shimadzu spectrophotometer UV-2600i with an integrating sphere. The light transmittance at 650nm visible light is collected for comparison. The resulting bar graph is as follows: Figure 7 As shown in Table 5, the test data comparison is as follows:

[0081] Table 5

[0082] Light blocking performance F1 F2 F3 F4 F5 F6 F7 Light transmittance 91.03％ 20.58％ 27.15％ 22.64％ 21.89％ 24.18％ 20.83％

[0083] Depend on Figure 7 From the data in Table 5, it can be seen that after adding 2% of resins with different stretch ratios or interface effects: styrene-methyl methacrylate copolymer MS, thermoplastic elastomer TPE, polymethyl methacrylate PMMA, polymethylpentene PMP, cycloolefin copolymer COC or aliphatic polyketone (POK), the above resins produce different degrees of interface light-blocking properties after blending with polyester PET, thereby improving the light-shielding property of the bottle, especially the interface light-blocking performance of styrene-methyl methacrylate copolymer MS is significantly more prominent.

[0084] Furthermore, pure polyester PET F1 was used as a reference sample, and 92 parts of polyester PET was used as a base carrier, mixed with 8 parts of different resin mixtures, including: styrene-methyl methacrylate copolymer MS, thermoplastic elastomer TPE, polymethylpentene PMP, cycloolefin copolymer COC, polymethyl methacrylate PMMA, and aliphatic polyketone (POK).

[0085] All mixed materials were purchased from the market, including Zhejiang Wankai bottle-grade polyester chips WK-801 with an intrinsic viscosity of 0.8 dL / g; MS was TX400S from Japan Electric Chemical; TPE was G2712 from GLS; PMP was TPXRT180 from Mitsui Chemicals; COC was Polyplastics 6013S from Japan; PMMA was IH830 from LG Chem; and POK was M630 from Hyosung, South Korea.

[0086] Nine different mixed materials were prepared according to the following ratios, as shown in Table 6:

[0087] Table 6

[0088]

[0089] The 9 mixed materials in Table 6 were injection molded into sheets, and 2.5 cm × 5 cm thin sheets with a thickness of 2 mm were cut and tested using a spectrophotometer (Shimadzu UV-2600i). For transmittance data, please refer to Figure 8 shown.

[0090] Depend on Figure 8 The data shows that adding styrene-methyl methacrylate copolymer (MS) or a compound mixture of MS with thermoplastic elastomers (TPE), polymethyl methacrylate (PMMA), polymethylpentene (PMP), cycloolefin copolymer (COC), aliphatic polyketone (POK), and other resins to polyester (PET) produces varying degrees of interfacial light-blocking properties, thereby improving the bottle's light-shielding properties. The light-blocking properties of mixtures of styrene-methyl methacrylate copolymer (MS) and several other resins in the same proportion are significantly more pronounced than those of styrene-methyl methacrylate copolymer alone in the same proportion. For example, compared to F9, F8 has a higher light transmittance than F9.

[0091] Furthermore, taking the mixing of styrene-methyl methacrylate copolymer MS and aliphatic polyketone (POK) in different ratios as an example, when the ratio of MS:POK is 6:2, the light blocking performance is better than that of the ratio of 4:4 or 3:5, that is, the light transmittance of F14 is lower than that of F13 and F15.

[0092] It can be seen that the appropriate ratio of different interface effect resins has a great influence on the improvement of light blocking properties.

[0093] Furthermore, based on Table 6 and Figure 8 The test results address two questions: Does a properly proportioned mixture of two polymers based on a more pronounced interface effect (MS) have better light-blocking properties than a mixture of any other two resins with interface effects? Does a mixture with more interface effect resins have better light-blocking properties? The applicant conducted the following test cases, in which the material manufacturers and brands in F16-F25 were identical to those in F1-F15, and the drying, weighing, and other processing procedures were identical. The proportions of F16-F25 are shown in Table 7:

[0094] Table 7

[0095] F16 F17 F18 F19 F20 F21 F22 F23 F24 F25 PET 92 92 92 92 92 92 92 92 92 92 MS 4 3.5 5 6 TPE 4 4 2 2 PMP 4 4 1.5 COC 4 1 PMMA 4 4 4 1 1 POK 4 4 4 4 2 1 1 1 100 100 100 100 100 100 100 100 100 100

[0096] The 10 mixtures of the above F16-F25 were injection molded into sheets, and 2.5cm×5cm thin sheets with a thickness of 2mm were cut and tested with a spectrophotometer (Shimadzu UV-2600i). The transmittance data are as follows: Figure 9 shown.

[0097] The light transmittance test data of F16-F21 can be used to conclude that, under the same mixing ratio, the combination of a polymer material based on MS (styrene-methyl methacrylate copolymer) with a more prominent interface effect and another interface effect resin has a relatively more prominent light-blocking performance than the combination of any other two polymer materials with weaker interface effects. Therefore, when designing a light-blocking formula, MS (styrene-methyl methacrylate copolymer) should be used as the main mixing component.

[0098] Comparing the light transmittance test data of F22-F25, it can be seen that the light blocking property of the mixture of three or more polymers with interface effect based on MS (styrene-methyl methacrylate copolymer) (average transmittance 4.91%) is close to the light blocking property of the mixture of two polymer materials with interface effect based on MS (styrene-methyl methacrylate copolymer) (average transmittance 4.74%), and is even slightly worse than the light blocking property of the mixture of two polymer materials with effect based on MS. The F23 (MS: TPE: PMP: POK = 3.5:2:1.5:1) sheet was scanned by electron microscope (such as Figure 10 The electron microscope is CIQTEK SEM5000.

[0099] Based on electron microscopic analysis, the applicant believes that the accumulation of multiple interfacial resins within the PET base resin influences or amplifies the interfacial effects and microbubble structures inherent in each individual material, creating a more pronounced fractured interlayer structure. These fractured interlayer structures allow light to penetrate more easily, thereby somewhat weakening the positive interfacial light-blocking properties. Furthermore, the production and processing of a mixture of two polymer materials is more convenient than mixing three or more polymer materials with varying proportions.

[0100] Furthermore, different polymers and polyester materials may have poor compatibility problems under specific ratios or specific processing conditions, which may lead to film wall delamination or a decrease in bottle physical properties and toughness after injection molding or bottle blowing. It can be considered to add a compatibilizer or grafting agent to improve the compatibility of the polymer and polyester plastic. These compatibilizers or grafting agents include but are not limited to POE grafted glycidyl methacrylate (POE-g-GMA), polypropylene grafted maleic anhydride (PP-g-MAH), polyethylene grafted maleic anhydride (PE-g-MAH), POE grafted maleic anhydride (POE-g-MAH), etc. Tests show that adding a low proportion (such as 0.5% to 2%) of the compatibilizer has little effect on the light-blocking properties of the bottle, but can improve the elongation at break of the mixture and improve the flexibility. The specific test data are shown in Table 8 below:

[0101] Table 8

[0102]

[0103] Because styrene-methyl methacrylate copolymer alone or in combination with other polymers in a specific proportion has a significant interfacial light-blocking synergistic effect, the amount of titanium dioxide used for light blocking in the light-blocking masterbatch formula can be significantly reduced. At the same time, in order to improve the light-blocking performance, other metal pigments with high hiding power (metallic aluminum pigments or bronze fragments) and other high-hiding inorganic substances that can play a steric role can be combined with it, such as calcined kaolin, calcite powder, silica powder, zinc oxide, barium sulfate, zinc sulfide, calcium carbonate or pearlescent mica, as well as other fillers with covering effects: metal oxide particles; specifically including: iron oxide red (PR 101), iron oxide black (PBlk 11), chrome green-black hematite (PG 17), cobalt aluminate (PB 28) or aluminum trihydrate (Al(OH)3), etc.

[0104] Steric hindrance, also known as the stereo effect, primarily refers to the spatial hindrance caused by the proximity of extremely small particles or molecular groups. To achieve ideal light-blocking and whiteness effects, the formulation of a light-blocking masterbatch based on styrene-methyl methacrylate copolymer should minimize the use of titanium dioxide. Typically, the titanium dioxide content (preferably rutile) in the formulation should not exceed 50%. Depending on specific requirements, it can be no more than 40%, or even no more than 30%. Combined with specific proportions of metallic pigments and other inorganic fillers, excellent light-blocking effects can also be achieved while maintaining higher whiteness and processing performance.

[0105] In order to facilitate the processing and production of light-blocking masterbatch and improve the dispersibility and processing performance, it is considered to add dispersants or internal and external lubricants during granulation production, including but not limited to polyethylene wax, EVA wax, monopolyester wax, stearate glycerol GMS, stearates (such as calcium stearate, magnesium stearate, zinc stearate, etc.), amide wax (vinyl bisstearamide EBS, erucamide, oleamide, etc.), pentaerythritol stearate PETS, etc. The introduction of wax will also have a positive effect on the light-blocking performance.

[0106] In addition, according to the final application requirements, pigments or organic dyes can be directly added to the light-blocking masterbatch formula to improve whiteness or present a colorful light-blocking effect. These pigments or dyes include but are not limited to the following red, yellow and blue primary colors of organic or inorganic substances, as shown in Table 9 below:

[0107] Table 9

[0108]

[0109]

[0110] Based on these commonly used pigments or dyes, colorful high-light-resistance bottles that meet production requirements can be produced, thereby increasing consumers' relevance and recognition of the food and beverages in the packaging bottles.

[0111] In addition, according to the production and terminal application requirements, other functional additives are added in this embodiment to improve the quality and stability of the bottle or the contents.

[0112] Antioxidants are added, including but not limited to high molecular weight hindered phenol antioxidants, solid organic phosphite antioxidants, etc.

[0113] Add additives that can improve the heat absorption performance of polyester, such as carbon black, tungsten oxide, activated carbon, titanium nitride, zinc nitride, etc.

[0114] Add light stabilizers such as UV234, UV1577, UV1164, UV360, UV3638, etc.

[0115] It also includes antistatic agents such as cationic surfactants or anionic surfactants.

[0116] According to the idea of ​​the present invention, the corresponding raw materials were purchased from the market to produce the following experimental examples:

[0117] Experimental Example 1: 25% styrene-methyl methacrylate copolymer MS (Nippon Denki Chemical TX400S), 25% thermoplastic polyester elastomer TPEE (DuPont TPEE 4556), 35% titanium dioxide (Chemours R-902), 2% metal aluminum paste (ECKARTMASTERSAFE MP100-20B), 11% barium sulfate (Sakai Chemical BARIACE B-34), and 2% auxiliary agents such as polyester wax / antioxidant (SI Group).

[0118] Experimental Example 2, styrene-methyl methacrylate copolymer MS (Nippon Denki Chemical TX400S) 30%, thermoplastic polyester elastomer TPEE (DuPont TPEE 4556) 20%, titanium dioxide (Chemours R-902) 35%, metal aluminum paste (ECKARTMASTERSAFE MP100-20B) 2%, barium sulfate (Sakai Chemical BARIACE B-34) 11% and auxiliary agents such as polyester wax / antioxidant (SI Group) 2%.

[0119] Experimental Example 3, styrene-methyl methacrylate copolymer MS (Nippon Denki Chemical TX400S) 40%, thermoplastic polyester elastomer TPEE (DuPont TPEE 4556) 10%, titanium dioxide (Chemours R-902) 35%, metal aluminum paste (ECKARTMASTERSAFE MP100-20B) 2%, barium sulfate (Sakai Chemical BARIACE B-34) 11% and auxiliary agents such as polyester wax / antioxidant (SI Group) 2%.

[0120] Experimental Example 4, styrene-methyl methacrylate copolymer MS (TX400S from Nippon Electric Chemical) 35%, PMMA (IH830 from LG Chemical) 10%, titanium dioxide (Chemours R-902) 35%, metal aluminum paste (ECKART MASTERSAFE MP100-20B) 2%, barium sulfate (SAKAI BARIACE B-34) 11% and auxiliary agents such as polyester wax / antioxidant (SI Group) 2%.

[0121] Experimental Example 5, thermoplastic polyester elastomer TPEE (DuPont TPEE 4556) 35%, PMMA (LG Chemical's IH830) 15%, compatibilizer (POE-g-MAH, Mitsui Chemicals MH5020) 1.5%, titanium dioxide (Chemours R-902) 37%, metal aluminum paste (ECKART MASTERSAFE MP100-20B) 1.5%, zinc oxide (Lutai LT-AH01) 8% and auxiliary processing aids such as stearate / UV stabilizer (BASF) 2%.

[0122] Experimental Example 6, polymethylpentene PMP (Mitsui Chemicals TPXRT180) 35%, PMMA (LG Chemical's IH830) 15%, compatibilizer (POE-g-MAH, Mitsui Chemicals MH5020) 1.5%, titanium dioxide (Chemours R-902) 37%, metal aluminum paste (ECKARTMASTERSAFE MP100-20B) 1.5%, zinc oxide (Lutai LT-AH01) 8% and auxiliary processing aids such as stearate / UV stabilizer (BASF) 2%.

[0123] Experimental Example 7, styrene-methyl methacrylate copolymer MS (Nippon Denki Chemical TX400S) 40%, polymethylpentene PMP (Mitsui Chemicals TPXRT180) 10%, compatibilizer (PP-g-MAH, Arkema 18732) 1%, titanium dioxide (Chemours R-902) 39%, metal aluminum paste (ECKART MASTERSAFE MP100-20B) 1%, calcined kaolin (BASF Translink37) 7%, monoglyceride GMS / EBS wax and other processing aids (Honeywell) 1.8% and ultramarine pigment (Holliday 5012) 0.2%.

[0124] Experimental Example 8, styrene-methyl methacrylate copolymer MS (TX400S from Japan Electric Chemical Co., Ltd.) 40%, cycloolefin copolymer COC (Polyplastics 6013S from Japan) 10%, compatibilizer (PP-g-MAH, Arkema 18732) 1%, titanium dioxide (Chemours R-902) 39%, metal aluminum paste (ECKART MASTERSAFE MP100-20B) 1%, calcined kaolin (BASF Translink37) 7%, monoglyceride GMS / EBS wax and other processing aids (Honeywell) 1.8% and ultramarine pigment (Holliday 5012) 0.2%.

[0125] Experimental Example 9, styrene-methyl methacrylate copolymer MS (Japan Electric Chemical TX400S) 40%, aliphatic polyketone POK (Korea Hyosung M630) 10%, compatibilizer (PP-g-MAH, Arkema 18732) 1%, titanium dioxide (Chemours R-902) 39%, metal aluminum paste (ECKART MASTERSAFE MP100-20B) 1%, calcined kaolin (BASF Translink37) 7%, monoglyceride GMS / EBS wax and other processing aids (Honeywell) 1.8% and ultramarine pigment (Holliday 5012) 0.2%.

[0126] Production process:

[0127] All materials from the above experiments were mixed in a hydraulic constant-pressure internal mixer or dispersed at high speed in a high-speed mixer to form a uniform mixture. The mixture was then directly fed into a temperature-controlled twin-screw extruder for granulation. The main process included plasticization, vacuuming, extrusion, air or water cooling, air drying, shearing, screening on a vibrating screen with air flow, dehumidification and drying, and finally weighing and packaging. Small quantities of granules or powders can also be added in appropriate proportions via a side feeder. In a production embodiment of the present invention, the typical process values ​​are set as follows: 1. The extruder screw section is set as the feed temperature section: 280℃~290℃, the equilibrium temperature section: 270℃~280℃, and the discharge temperature section: 260℃~270℃; the side feeding zone is the equilibrium temperature zone: 260℃; the vacuum degree of the vacuum section is controlled to be 0.6~0.8Mpa; the extrusion section temperature: 260℃; circulating cooling water cooling; three-stage blower air drying method; pelletizer speed: 800~900r / min; vibration screen for uniform particles, water centrifugal separation and drying; dehumidification and drying; metering, weighing and packaging.

[0128] For the nine experimental examples above, as well as a conventional high-light-blocking masterbatch (Hanhui LBS-1, formulated with 30% PET as the base resin and approximately 70% titanium dioxide, metallic pigments, carbon black, and other inorganic ingredients), after drying at 90°C for two hours, all ten samples were injection molded into preforms (injection molding machine: Zhenxiong EM120-SVP) using 90% bottle-grade polyester chips (Zhejiang Wankai WK-801, dried at 170°C for six hours) at a 10% by mass ratio. These preforms were then blown into bottles (blow molding machine: Langs LS-T12). Approximately 4 cm x 4 cm, 0.26 mm thick, bottle wall slices were cut and tested for whiteness using a Konica Minolta CM-3700A chromatograph. The results are shown in Table 10 below:

[0129] Table 10

[0130]

[0131] In addition, combined Figure 11 From the data in Table 10, it can be seen that the whiteness of the bottle prepared based on the solution of the present invention is significantly improved compared with the whiteness of the bottle prepared with traditional high light-blocking masterbatch.

[0132] Compare the light-blocking properties of PET bottles blown from the above ten groups of samples. Take three bottles from each group, cut a 2.5cm×5cm thin slice of 0.3mm thickness from the same part, and use a Shimadzu UV-2600i spectrophotometer with an integrating sphere to test the light transmittance. Select the curve in the middle or overlapping of the three samples in each group. The comparison results are as follows: Figure 12 shown.

[0133] Figure 12 It can be clearly seen that the light-blocking solution based on this invention significantly improves light-blocking performance compared to traditional high-light-blocking masterbatches at the same addition ratio. In particular, styrene-methyl methacrylate copolymer (MS) with aliphatic polyketone (POK), cycloolefin copolymer (COC), or polymethylpentene (PMP) exhibits superior light-blocking performance. This test data was obtained when the titanium dioxide content in the bottle (between 3.5% and 4%) was approximately half that of traditional light-blocking masterbatches (around 7%).

[0134] Because the inventive solution of the present application has better compatibility with polyester PET and is easier to disperse evenly with the molten polyester in the screw of the injection molding machine, the injection temperature can be appropriately reduced by 3-5°C when injecting the embryo compared with traditional high-light-resistance masterbatch. In particular, it can even be reduced by 5-8°C in the first and second injection stages, which significantly saves processing energy consumption, improves the yield of the bottle embryo to a certain extent, and also improves the size and appearance of the bottle embryo, such as pinholes, tailing, flash, stress distribution, etc.

[0135] In terms of bottle blowing, the present invention is easier to blow into shape, the bottle blowing process window is wider, the molding is better, the bottom foot standing surface is fuller at all angles, the pre-blowing time and pressure can be appropriately reduced, and the bottle body pressure is more stable. Compared with Experimental Example 2 in the present invention and the traditional high-resistance masterbatch (Hanhui LBS-1), both were blown at a 10% addition ratio to form a 21g container bottle with a volume of 350ml. Compared with the vertical pressure of the empty bottle, the two groups of comparative effects are as follows: Figure 13 - Figure 14 shown.

[0136] Specifically, the masterbatch prepared in Experimental Example 2 of this application was weighed according to a 10% ratio, and evenly blended with 90% dried polyester PET (Wankai WK-801), and then preformed and blown into bottles. Ten bottles were taken as sample bottles and marked with 1-10; 10% of traditional light-blocking masterbatch (LBS-1, a commercially available product of Hanhui) was weighed, and preformed and blown into bottles with 90% dried polyester PET (Wankai WK-801), and 10 bottles were taken as control bottles and marked with 1-10. The above two groups of samples were subjected to an empty bottle vertical load pressure test using the Alpha vertical load pressure tester XLW-B. The load pressure yield curve and load pressure stability curve are shown as follows: Figure 13 - Figure 14 shown.

[0137] from Figure 13 - Figure 14 It can be seen from the two comparison curves that Experimental Example 2 based on the present invention has a higher yield strength and a more stable pressure bearing capacity under empty bottle load pressure, which also shows that the bottle based on Experimental Example 2 of the present invention has better strength and toughness.

[0138] 10% of the masterbatch prepared in Experimental Example 2 was weighed and uniformly blended with 90% dried PET (Wankai WK-801). The mixture was then blown into preforms. Eight bottles were used as sample bottles, filled with water, and the caps were tightened. The sample bottles were labeled "sample bottles 1-8." 10% of a conventional light-blocking masterbatch (LBS-1, a commercially available product from Hanhui) was weighed and blended with 90% dried PET (Wankai WK-801). Eight bottles were used as control bottles, filled with water, and the caps were tightened. The control bottles were labeled "control bottles 1-8." Drop tests were conducted using a Zhuyan BFI-20 drop tester, using two drop test conditions: 1.4 m / 4°C and 1.4 m / 4°C / 30 kPa. Each bottle was tested for both vertical and horizontal drops under each condition. The test results are shown in Table 11 below.

[0139] Table 11

[0140]

[0141] Bottles 1-8 all passed the drop test. Bottles using conventional high-light-blocking masterbatch all passed the test at 1.4 m / 4°C, but exhibited varying degrees of deformation in both vertical and horizontal drops at 1.4 m / 4°C / 0.3 bar. These tests demonstrate that the bottles in Experimental Example 2, based on this invention, exhibit significant improvements in toughness and strength.

[0142] In order to compare the energy consumption of blowing bottles in the examples of the present invention and traditional high-light-blocking masterbatch, a blowing process verification was carried out (blowing machine: Sidel SBO 2 / / 10 10433). After the blowing process was adjusted and stabilized, the blowing temperature setting of the present invention was lower than that of the traditional light-blocking masterbatch. The blowing temperature could be reduced by about 5°C on average, from 128°C, the commonly used blowing temperature of the traditional light-blocking masterbatch, to 123°C. The blowing energy consumption was reduced by 4%, ((128-123) / 128=4%). This is because styrene-methyl methacrylate copolymer or a mixture of styrene-methyl methacrylate copolymer and other resins in corresponding proportions has better fusion, fluidity and dispersibility in PET polyester, and is easier to blow into bottles, so the blowing pressure and blowing temperature can be reduced to a certain extent during blowing.

[0143] According to the above blowing energy consumption comparison test, the 4% saving, the annual consumption of polyester chips with high light-blocking additives for dairy packaging is 1 million tons, the empirical value of energy consumption for blowing each ton of polyester light-blocking bottle blanks is 230 kWh (the power consumption of different blowing equipment may be different, the data here is only for example), the electricity fee is 1 yuan / kWh (refer to the average industrial electricity fee on the market), and 1 kWh of electricity consumption is equivalent to 0.997 kg of CO2 emissions (based on the data of the Carbon Emission Trading Network). The use of the invention scheme of this application can save more than 90 million yuan in electricity bills and reduce more than 9,000 tons of carbon emissions in a year. The data is shown in Table 12, and the energy consumption savings in the injection molding stage are not even calculated.

[0144] Table 12

[0145]

[0146] Example 2

[0147] In addition, this embodiment also provides a method for preparing a high-efficiency light-blocking masterbatch with high whiteness and low titanium dioxide content, which is used to prepare the light-blocking masterbatch in Example 1, comprising the following steps:

[0148] Disperse the formulated materials into a uniform mixture and granulate.

[0149] The granulation process comprises:

[0150] The mixture is heated to the plasticizing temperature and vacuumed;

[0151] Passing the plasticized material through an extruder to form a continuous molten extrudate;

[0152] Cooling to form solid particles;

[0153] The solid particles are cut into predetermined sizes and then screened for rejection.

[0154] Furthermore, during the granulation process, the feed temperature section is set at 280°C to 290°C, the equilibrium temperature section is set at 270°C to 280°C, and the discharge temperature section is set at 260°C to 270°C.

[0155] The vacuum degree of the vacuum section is controlled at 0.6-0.8 MPa; the temperature of the extrusion section is 260°C; the speed of the pelletizer is 800-900 r / min.

[0156] Specifically, the method may include the following specific steps:

[0157] All ingredients in the formulation are mixed in a hydraulic constant-pressure internal mixer or dispersed into a uniform mixture at high speed in a high-speed mixer. The mixture is then fed directly into a temperature-controlled twin-screw extruder for granulation. The main process includes plasticization, vacuuming, extrusion, air or water cooling, air drying, rotary cutting, screening on a vibrating screen with air flow, dehumidification and drying, and finally weighing and packaging. Small amounts of granules or powders can also be added in appropriate proportions through a side feeder.

[0158] In a specific production embodiment of the present invention, the typical process values ​​are set as follows: 1. The extruder screw section is set as the feed temperature section: 280℃~290℃, the equilibrium temperature section: 270℃~280℃, and the discharge temperature section: 260℃~270℃; the side feeding zone is the equilibrium temperature zone: 260℃; the vacuum degree of the vacuum section is controlled to be 0.6~0.8Mpa; the extrusion section temperature: 260℃; circulating cooling water cooling; three-stage blower air drying method; pelletizer speed: 800~900r / min; vibration screen for uniform particles, water centrifugal separation and drying; dehumidification and drying; metering, weighing and packaging.

[0159] The present invention also provides a production line for high-whiteness and low-titanium dioxide content high-efficiency light-blocking masterbatch, comprising: an internal mixer or a high-speed mixer, an extruder, a blower, a pelletizer and a dehumidifying and drying device.

[0160] The internal mixer or high-speed mixer is used to disperse the materials into a uniform mixture, the extruder is used to granulate the mixture, and the dehumidification and drying device is used to dehumidify and dry the granules.

[0161] Furthermore, the extruder also includes an air blowing device and a pelletizing device. The air blowing device is used to dry the plasticized and extruded material, and the pelletizing device is used to cut the dried material into granules.

[0162] In summary, the scheme of the present invention selects styrene-methyl methacrylate copolymer as the basic carrier, and the styrene-methyl methacrylate copolymer is blended with polyester plastic to form an uneven and irregular interface effect during the stretching process of blowing and injecting the embryo, which scatters, refracts and reflects the light, reduces the transmittance of the light, and thus achieves a synergistic light-blocking effect; in order to maximize the interface effect, in addition to the styrene-methyl methacrylate copolymer, a high polymer that also has a certain interface effect with the polyester plastic is added; at the same time, a compatibilizer or a grafting agent is added to improve the compatibility of the polymer and the polyester plastic; under the same addition ratio, the light-blocking masterbatch disclosed by the present invention has higher whiteness and light-blocking properties, lower titanium dioxide content, and the energy consumption of injection molding and blowing can be significantly reduced, and the physical properties of the bottle body are better, the toughness effect is better, and the cost is lower.

[0163] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A high-whiteness, low-titanium dioxide content, high-efficiency light-blocking masterbatch, characterized in that: include: Styrene-methyl methacrylate copolymer resin, thermoplastic polymer material and titanium dioxide; The mass content of the styrene-methyl methacrylate copolymer resin is 5% to 60%, the mass content of the thermoplastic high polymer material is 3% to 30%, and the mass content of the titanium dioxide is 10% to 60%; The thermoplastic high polymer material includes one or more of thermoplastic elastomer TPE, polymethyl methacrylate PMMA, poly-4-methyl-1-pentene PMP, cycloolefin copolymer COC, thermoplastic polyester elastomer TPEE or aliphatic polyketone resin POK.

2. The high-whiteness, low-titanium dioxide content, high-efficiency light-blocking masterbatch according to claim 1, characterized in that: It also includes a high-covering inorganic substance with a mass content of 1% to 30%, and the high-covering inorganic substance includes one or more of calcined kaolin, calcite powder, silica powder, zinc oxide, barium sulfate, zinc sulfide or calcium carbonate.

3. The high-whiteness, low-titanium dioxide content, high-efficiency light-blocking masterbatch according to claim 1, characterized in that: The invention also includes a metal pigment with a mass content of 0.01% to 5%, wherein the metal pigment includes a metal aluminum pigment or a bronze pigment.

4. The high-whiteness, low-titanium dioxide content, high-efficiency light-blocking masterbatch according to claim 1, characterized in that: The invention also includes a compatibilizer with a mass content of 0.01% to 5%, wherein the compatibilizer includes one or more of POE-g-GMA, PP-g-MAH, PE-g-MAH or POE-g-MAH.

5. The high-whiteness, low-titanium dioxide content, high-efficiency light-blocking masterbatch according to claim 1, characterized in that: The invention also includes auxiliary agents with a mass content of 0.01% to 10%, wherein the auxiliary agents include one or more of a dispersing lubricant, an antioxidant, a reheat absorber, a light stabilizer or an antistatic agent; and the reheat absorber includes carbon black, tungsten oxide, activated carbon, titanium nitride or zinc nitride.

6. The high-whiteness, low-titanium dioxide content, high-efficiency light-blocking masterbatch according to claim 1, characterized in that: It also includes organic dyes with a mass content of 0.01% to 10%.

7. A method for preparing a high-whiteness, low-titanium dioxide content, high-efficiency light-blocking masterbatch, for preparing the high-whiteness, low-titanium dioxide content, high-efficiency light-blocking masterbatch according to any one of claims 1 to 6, characterized in that: include: Disperse the formula materials into a uniform mixture for granulation; The granulation process comprises: The mixture is heated to the plasticizing temperature and vacuumed; Passing the plasticized material through an extruder to form a continuous molten extrudate; Cooling to form solid particles; The solid particles are cut into predetermined sizes and then screened for rejection.

8. The method for preparing a high-whiteness, low-titanium dioxide content, high-efficiency light-blocking masterbatch according to claim 7, characterized in that: During the granulation process, the feed temperature section is set at 280°C to 290°C, the equilibrium temperature section is set at 270°C to 280°C, and the discharge temperature section is set at 260°C to 270°C.

9. The method for preparing a high-whiteness, low-titanium dioxide content, high-efficiency light-blocking masterbatch according to claim 7, characterized in that: During the granulation process, the vacuum degree in the vacuuming section is controlled to be 0.6-0.8 MPa; the temperature in the extrusion section is 260° C.; and the speed of the pelletizer is 800-900 r / min.

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