Modified PET (Polyethylene Terephthalate) material, preparation method thereof and refrigerator

Abstract

The invention discloses a modified PET material, a preparation method thereof and a refrigerator, and belongs to the technical field of refrigerator materials. According to the technical scheme, the PET plastic material is obtained by extruding and granulating raw materials, wherein the raw materials comprise PET plastic particles, a nucleation inhibition component and a lubricating component; the nucleation inhibition component comprises carboxyl-containing organic metal salt and an organic nucleation inhibitor, and the organic nucleation inhibitor is selected from polyethylene glycol derivatives; and the lubricating component is selected from at least one of triethyl citrate, acetyl tributyl citrate, dioctyl phthalate, dibutyl phthalate and sorbitol hexabenzoate. The preparation method is applied to refrigerator shelves, the problem that the application range of an existing PET material is limited due to transparency reduction caused by crystal formation in the forming process is solved, crystallization of the PET material in the forming process can be effectively controlled, the transparency of the PET material is guaranteed, and the mechanical property of the PET material is not affected.

Description

Technical Field

[0001] The present invention belongs to the technical field of refrigerator materials, and in particular relates to a modified PET material, a preparation method thereof, and a refrigerator. Background Art

[0002] GPPS (General Purpose Polystyrene) is a transparent, hard, and easy-to-process amorphous thermoplastic. It features high transparency (light transmittance >90%), excellent rigidity (flexural modulus approximately 3000 MPa), good processing fluidity (suitable for injection molding of complex structures), low cost (raw material prices are lower than those of engineering plastics such as ABS and PC), and resistance to weak acids and alkalis (but not resistant to oils, fats, and organic solvents). Therefore, GPPS is currently the mainstream material for refrigerator shelf components. However, GPPS suffers from low impact strength and susceptibility to stress cracking. It is also significantly brittle at low temperatures, making it prone to cracking.

[0003] PET (polyethylene terephthalate) is a thermoplastic polyester material with excellent physical, chemical, and processing properties. Its use in refrigerator shelves can address the problem of stress cracking. Chinese patent CN116907169A discloses shelf trims, refrigerators, and preparation methods. Specifically, the shelf trim comprises a trim base, a thermal transfer film, and a protective film, the protective film being made of polyethylene terephthalate (PET).

[0004] However, the PET material in the above patent and the existing PET material can only be used as a protective film for shelf trims, and cannot be used as the main body of the refrigerator shelf or other components that have requirements for transparency and mechanical properties. The reason is that PET material is a crystalline material, and the formation of crystals during the molding process can easily cause a decrease in transparency. Therefore, the existing PET material cannot meet the transparency requirements of these components. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the technical problem to be solved by the present invention is that the transparency of the existing PET material decreases due to the formation of crystals during the molding process, which limits its application range. A modified PET material, a preparation method thereof, and a refrigerator are proposed, which can effectively control the occurrence of crystallization during the molding process of the PET material, ensure the transparency of the PET material without affecting the mechanical properties of the PET material.

[0006] In order to solve the technical problem, the technical solution adopted by the present invention is:

[0007] In one aspect, the present invention provides a modified PET material obtained by extruding and granulating a raw material, wherein the raw material comprises: PET plastic particles, a nucleation inhibition component, and a lubricating component;

[0008] The nucleation inhibition component includes a carboxyl-containing organic metal salt and an organic nucleation inhibitor, wherein the organic nucleation inhibitor is selected from a polyethylene glycol derivative; the polyethylene glycol derivative is selected from at least one of polyethylene glycol, carboxylic acid polyethylene glycol, hydroxy-polyethylene glycol-carboxylic acid, and maleimide-polyethylene glycol-hydroxyl;

[0009] The lubricating component is selected from at least one of triethyl citrate, acetyl tributyl citrate, dioctyl phthalate, dibutyl phthalate, and sorbitol hexabenzoate.

[0010] The modified PET material is prepared by adding a nucleation-inhibiting component and a crystal nucleus-blocking lubricating component during the modification stage, thereby reducing the regularity of the PET molecular chain segments, increasing the mobility between the chain segments, and controlling the crystallization of the PET. This prevents crystallization from occurring during the molding process of the refrigerator shelf, thereby ensuring the light transmittance of the final product without affecting the mechanical properties of the material.

[0011] In some embodiments, the amount of PET plastic particles is selected from any value between 96.6 and 98.1 parts by weight, the amount of the nucleation inhibition component is selected from any value between 1 and 2 parts, and the amount of the lubricating component is selected from any value between 0.5 and 1 part.

[0012] If the amount of PET plastic particles is less than 96.6 parts, the amount of nucleation inhibition component and lubricating component added is relatively large, resulting in an increase in the cost of the entire material system, which cannot meet the cost requirements of use; if the amount of PET plastic particles is greater than 98.1 parts, the amount of nucleation inhibition component and lubricating component added is insufficient, and the effect of inhibiting crystallization cannot be achieved; if the amount of nucleation inhibition component is less than 1 part, the PET molecular chain segments cannot form sufficient hydrogen bond interactions with the nucleation inhibition component, and the effect of inhibiting crystallization clusters cannot be achieved; if the amount of nucleation inhibition component is greater than 2 parts, the cost increases significantly, and the product cost cannot meet the use requirements; if the amount of lubricating component is less than 0.5 parts, effective lubrication of the PET molecular chain segments cannot be achieved, and the effect of inhibiting PET crystallization cannot be achieved; if the amount of lubricating component is greater than 1 part, the cost increases significantly, and the cost requirements of use cannot be met.

[0013] In some embodiments, the organic metal salt is selected from at least one of sodium acetate, sodium formate, sodium citrate, potassium citrate, sodium benzoate, and sodium salicylate.

[0014] In some embodiments, the nucleation-inhibiting component is obtained by first eliminating static electricity from an organometallic salt and an organic nucleation inhibitor having a mesh size difference of ≤50 and then uniformly mixing to obtain the nucleation-inhibiting component. A mesh size difference of ≤50 between the organometallic salt and the organic nucleation inhibitor promotes the dispersion of the different components, ensuring uniform hydrogen bonding across all portions of the PET, thereby ensuring consistent crystallization properties of the PET.

[0015] In some embodiments, the raw material further comprises an antioxidant, and the amount of the antioxidant is selected from any value between 0.1 and 0.4 parts.

[0016] In some embodiments, the antioxidant is selected from at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, n-octadecylβ-(-4-hydroxy-3,5-di-tert-butylphenyl)propionate, tris(2,4-di-tert-butylphenyl) phosphite, and 3,9-bis(2,4-di-tert-butylphenoxy)-2,4,8,10-tetraoxo-3,9-diphosphabicyclo[5.5]undecane.

[0017] In some embodiments, the PET plastic particles are polyethylene terephthalate, having an intrinsic viscosity of 0.810 dL / g, an acetaldehyde content of less than 0.5 μg / g, a terminal carboxyl content of less than 30 ppm, a chromaticity b value ≤1.0, and an L value ≥80.

[0018] Another aspect of the present invention provides a method for preparing the modified PET material of any of the above technical solutions, wherein the raw materials are extruded and granulated through a twin-screw extruder; the processing temperature of the twin-screw extruder is 260-285° C.; and the screw speed is 450-650 r / min.

[0019] During the above-mentioned extrusion granulation process, the extrusion temperature is set to 260-285°C and the screw speed is 450-650r / min, which can effectively promote the dispersion of the nucleation inhibition component and the lubricating component, ensure the uniform distribution of the components in the PET material system, effectively promote the two components to play a role, and thus reduce the crystallization ability of the PET material.

[0020] In some embodiments, during the extrusion granulation process, the organic metal salt is hydrogen bonded to the terminal carboxyl group of the molten PET, and the terminal hydroxyl group of the polyethylene glycol derivative is hydrogen bonded to the carbonyl group in the middle of the PET chain segment. Under the dual action of the organic metal salt and the polyethylene glycol derivative, the regularity of the PET molecular chain segment is reduced, and the crystallization ability of the PET molecule is reduced. At the same time, the lubricating component is inserted between the PET molecular chains, and through steric hindrance and polar interactions, the van der Waals force and dipole-dipole effect are reduced, so that the chain segment slip energy barrier is reduced, the chain segment activity and chain segment movement ability are improved, the glass transition temperature is lowered, the regular arrangement of the molecular chain is destroyed, and the crystallization process is hindered.

[0021] The present invention also provides a refrigerator having a shelf formed by injection molding the modified PET material according to any of the above technical solutions. By adding a nucleation inhibitor and a crystallization barrier during the PET modification stage, the present invention controls the crystallization of the PET, preventing crystallization during the molding process of the refrigerator shelf. This ensures the light transmittance of the final product and achieves a highly transparent refrigerator shelf molded by PET injection molding. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of the preparation process of the modified PET material provided in an embodiment of the present invention;

[0023] Figure 2 Schematic diagram of the effect of the organic sodium salt provided in an embodiment of the present invention on the crystallization properties of PET;

[0024] Figure 3 Schematic diagram of the effect of polyethylene glycol on the crystallization properties of PET provided by an embodiment of the present invention;

[0025] Figure 4 Schematic diagram of the effect of the lubricating component provided by an embodiment of the present invention on the PET molecular chain segment;

[0026] Figure 5 This is a DSC test result diagram provided by Example 1 of the present invention;

[0027] Figure 6 This is a DSC test result diagram provided for Comparative Example 3 of the present invention. DETAILED DESCRIPTION

[0028] The following is a detailed and complete description of the technical solutions in specific embodiments of the present invention, with reference to the accompanying drawings. It should be understood that the described embodiments are merely partial implementations of the overall technical solution of the present invention, and are not exhaustive. All other embodiments derived by those skilled in the art based on the overall concept of the present invention are intended to fall within the scope of protection of the present invention.

[0029] The invention provides a modified PET material obtained by extruding and granulating raw materials, wherein the raw materials include PET plastic particles.

[0030] Currently, the main material used for refrigerator shelves is GPPS, but due to its poor toughness, GPPS is prone to cracking. PET, a thermoplastic polyester material with excellent physical, chemical, and processing properties, can be used in refrigerator shelves to address this stress cracking issue. However, because PET is a crystalline material, the formation of crystals during the molding process can easily lead to a decrease in transparency. Therefore, existing PET materials cannot meet the transparency requirements of refrigerator shelves, which in turn limits the application of PET materials in the home appliance field, resulting in existing PET materials being used only in home appliance components with low transparency requirements.

[0031] In some embodiments, the PET plastic particles are polyethylene terephthalate (PET) having an intrinsic viscosity of 0.810 dL / g, an acetaldehyde content of less than 0.5 μg / g, a carboxyl end group content of less than 30 ppm, a color b value ≤ 1.0, and an L value ≥ 80. This technical solution provides the viscosity, acetaldehyde content, carboxyl end group content, color b value, and L value of the PET plastic particles because, for refrigerator shelf materials, considering the material's color, toughness, rigidity, and processing performance, the viscosity, color, and small molecule content of the PET plastic particles must all meet the aforementioned conditions to meet the requirements for use as refrigerator shelf materials.

[0032] A modified PET material is obtained by extruding and granulating a raw material, wherein the raw material includes a nucleation inhibition component.

[0033] PET is a crystalline polymer that is prone to crystallization during the injection molding process. Increased crystallinity can cause the finished product to appear white. To address this crystallization issue during injection molding, the primary industry approach is to add 1,4-cyclohexanedimethanol (1,4-cyclohexanedimethanol) to the PET polymerization process to control the regularity of the PET molecular chain, rendering the material non-crystalline. However, the addition of 1,4-cyclohexanedimethanol significantly increases the price of PET, hindering the mass production of PET injection-molded shelving. The present invention addresses this whitening issue by adding a nucleation inhibitor component, reducing the crystallinity of the PET injection molding process without introducing a third monomer.

[0034] Nucleation inhibition components include carboxyl-containing organic metal salts, such as Figure 2 As shown, a nucleation inhibitory component is added to the PET material at a ratio of 0.2-2wt%. The organic sodium salt component in the nucleation inhibitor combines with the terminal carboxyl groups of the molten PET through hydrogen bonds, reducing the regularity of the molecular chain and preferentially occupying the nucleation sites, inhibiting the formation of crystal nuclei and controlling the crystallization performance of the system.

[0035] The nucleation inhibition component includes an organic nucleation inhibitor selected from polyethylene glycol derivatives. Figure 3 As shown, the polyethylene glycol derivative in the nucleation inhibition component forms hydrogen bonds with the carbonyl group in the middle of the PET chain segment, restricting the movement of the molecular chain segment. The hydrophobic effect of the polyethylene glycol derivative adsorbs on the surface of the PET crystal, forming a physical barrier that hinders the migration of the molecular chain to the crystal lattice.

[0036] The interaction between the organic sodium salt and the polyethylene glycol derivative on the PET molecular chain segments reduces the growth rate of PET crystals and decreases crystallinity. The nucleation inhibition component, which includes the organic sodium salt and the organic nucleation inhibitor, forms hydrogen bonds with the carboxyl groups at the end of the PET, while the organic nucleation inhibitor forms hydrogen bonds with the carbonyl groups in the middle of the PET chain segments. Under the combined action of hydrogen bonds, the regularity of the PET molecular segments decreases, the rate of crystal nucleation formation slows, and the crystallization performance of the system decreases, thereby ensuring the transparency of the PET material.

[0037] The polyethylene glycol derivative is selected from at least one of polyethylene glycol, carboxylic acid polyethylene glycol, hydroxy-polyethylene glycol-carboxylic acid, and maleimide-polyethylene glycol-hydroxy. It is understood that the type of polyethylene glycol derivative can also be other substances reasonably selected by those skilled in the art in the art.

[0038] A modified PET material is obtained by extruding and granulating a raw material, wherein the raw material includes a lubricating component. The lubricating component is selected from at least one of triethyl citrate, acetyl tributyl citrate, dioctyl phthalate, dibutyl phthalate, and sorbitol hexabenzoate.

[0039] The processing temperature of PET material is relatively high, and its processing performance is poorer than that of general plastics. The addition of chain segment lubricating components can improve the processing performance of PET material, weaken the force of molecular chain parts, increase the activity of chain segments, and enhance the chain segment movement ability. At the same time, due to the addition of nucleation inhibitory components, the regular arrangement of molecular chains is destroyed, which hinders the crystallization of PET and realizes the realization of transparent PET injection molding shelves. Figure 4 As shown in the figure, lubricating components are added to the PET material. The lubricating components are inserted between the PET molecular chains, which effectively reduce the van der Waals force and dipole-dipole effect through steric hindrance effect and polar interaction, thereby reducing the chain segment slip energy barrier, improving the chain segment activity and chain segment movement ability, lowering the glass transition temperature (Tg), destroying the regular arrangement of the molecular chains, and hindering the crystallization process.

[0040] It should be noted that the present invention adds a nucleation-inhibiting component and a lubricating component to a raw material system comprising PET plastic particles. The nucleation-inhibiting component comprises an organic metal salt and an organic nucleation inhibitor, the organic nucleation inhibitor being selected from a polyethylene glycol derivative, and the lubricating component being selected from at least one of triethyl citrate, acetyl tributyl citrate, dioctyl phthalate, dibutyl phthalate, and sorbitol hexabenzoate. During the cooling process of the PET shelf material after forming, the organic sodium salt of the PET material containing the nucleation-inhibiting component forms hydrogen bonds with the carboxyl groups at the end of the PET, and the organic nucleation inhibitor forms hydrogen bonds with the carbonyl groups in the middle of the PET chain segments. These combined hydrogen bonds reduce the regularity of the PET molecular segments and inhibit crystallization clustering. Without the nucleation-inhibiting component, the PET molecular segments rapidly begin to form small crystalline clusters in the ordered regions. When the crystalline clusters grow to a certain critical size, they transform into initial crystal nuclei. The presence of these initial crystal nuclei accelerates the integration of the PET macromolecular segments into the crystal lattice, transforming disorder into order and promoting crystallization of the PET molecular segments. However, the free energy of molecular thermal motion of PET macromolecules with added lubricating components is significantly greater than the cohesive energy, making it difficult to form an ordered structure in the polymer, thereby reducing the crystallization of PET materials during processing.

[0041] In some embodiments, the amount of PET plastic particles is selected from any value between 96.6 and 98.1 parts by weight.

[0042] The amount of PET plastic particles can also be 96.7 parts, 96.8 parts, 96.9 parts, 97.0 parts, 97.1 parts, 97.2 parts, 97.3 parts, 97.4 parts, 97.5 parts, 97.6 parts, 97.7 parts, 97.8 parts, 97.9 parts, 98.0 parts and any point value within the range. If the amount of PET plastic particles is less than 96.6 parts, the amount of nucleation inhibition component and lubricating component added is relatively large, resulting in an increase in the cost of the entire material system and failure to meet the cost requirements of use. If the amount of PET plastic particles is greater than 98.1 parts, the amount of nucleation inhibition component and lubricating component added is insufficient, and the effect of inhibiting crystallization cannot be achieved.

[0043] In some embodiments, the amount of the nucleation inhibiting component is selected from any value between 1 and 2 parts by weight.

[0044] The amount of the nucleation inhibitory component can also be 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts and any point value within the range. If the amount of the nucleation inhibitory component is less than 1 part, the PET molecular segments cannot form sufficient hydrogen bond interactions with the nucleation inhibitory component, and the effect of inhibiting crystal clusters cannot be achieved. If the amount of the nucleation inhibitory component is greater than 2 parts, the cost increases significantly and the product cost cannot meet the use requirements.

[0045] The ratio of the carboxyl-containing organic metal salt to the organic nucleation inhibitor in the nucleation inhibition component is 1:1-1:5. In the system of the present invention, the carboxyl-containing organic metal salt functions to form hydrogen bonds with the terminal carboxyl groups, while the organic nucleation inhibitor functions to form hydrogen bonds with the mid-segment of the chain segment. The two components, when used in a defined ratio, can effectively maintain the hydrogen bond density at each position of the PET molecular chain segment.

[0046] In some embodiments, the amount of the lubricating component is selected from any value between 0.5 and 1 part by weight.

[0047] The amount of the lubricating component can also be 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts and any point value within the range. If the amount of the lubricating component is less than 0.5 parts, effective lubrication of the PET molecular segments cannot be achieved, and the effect of inhibiting PET crystallization cannot be achieved. If the amount of the lubricating component is greater than 1 part, the cost increases significantly and the cost requirements cannot be met.

[0048] In some embodiments, the organic metal salt is selected from at least one of sodium acetate, sodium formate, sodium citrate, potassium citrate, sodium benzoate, and sodium salicylate. It is understood that the organic metal salt may also be an organic potassium salt selected from at least one of potassium acetate, potassium formate, potassium citrate, potassium benzoate, and potassium salicylate.

[0049] In some embodiments, the nucleation inhibition component is obtained by the following method: an organic metal salt with a mesh size difference of ≤50 and an organic nucleation inhibitor are firstly subjected to static elimination and then uniformly mixed to obtain the nucleation inhibition component.

[0050] The mesh size difference between the organometallic salt and the organic nucleation inhibitor is ≤50, which promotes the dispersion of the different components and ensures uniform hydrogen bonding across all parts of the PET, thereby ensuring consistent crystallization properties of the PET. The present invention also treats the organometallic salt and the organic nucleation inhibitor to eliminate static electricity, as static electricity can affect the dispersibility of the PET material during blending. Poor dispersion results in uneven distribution of the components, thus reducing the impact of the nucleation inhibitor on crystallization properties.

[0051] In some embodiments, the raw materials further include an antioxidant, and the amount of the antioxidant is selected from any value between 0.1 and 0.4 parts, and can also be 0.2 parts, 0.3 parts, and any value within the range.

[0052] In some embodiments, the antioxidant is selected from at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, n-octadecylβ-(-4-hydroxy-3,5-di-tert-butylphenyl)propionate, tris(2,4-di-tert-butylphenyl) phosphite, and 3,9-bis(2,4-di-tert-butylphenoxy)-2,4,8,10-tetraoxo-3,9-diphosphabicyclo[5.5]undecane.

[0053] Another aspect of the present invention provides a method for preparing the modified PET material of any of the above technical solutions, wherein the raw materials are extruded and granulated through a twin-screw extruder; the processing temperature of the twin-screw extruder is 260-285° C.; and the screw speed is 450-650 r / min.

[0054] During the above-mentioned extrusion granulation process, the extrusion temperature is set to 260-285°C and the screw speed is 450-650r / min, which can effectively promote the dispersion of the nucleation inhibition component and the lubricating component, ensure the uniform distribution of the components in the PET material system, effectively promote the two components to play a role, and thus reduce the crystallization ability of the PET material.

[0055] In some embodiments, the twin-screw extruder comprises seven temperature zones, namely, the first zone at 240°C, the second zone at 255°C, the third zone at 260°C, the fourth zone at 265°C, the fifth zone at 270°C, the sixth zone at 280°C, and the seventh zone at 285°C.

[0056] In some embodiments, during the extrusion granulation process, the organic metal salt is hydrogen bonded to the terminal carboxyl group of the molten PET, and the terminal hydroxyl group of the polyethylene glycol derivative is hydrogen bonded to the carbonyl group in the middle of the PET chain segment. Under the dual action of the organic metal salt and the polyethylene glycol derivative, the regularity of the PET molecular chain segment is reduced, and the crystallization ability of the PET molecule is reduced. At the same time, the lubricating component is inserted between the PET molecular chains, and through steric hindrance and polar interactions, the van der Waals force and dipole-dipole effect are reduced, so that the chain segment slip energy barrier is reduced, the chain segment activity and chain segment movement ability are improved, the glass transition temperature is lowered, the regular arrangement of the molecular chain is destroyed, and the crystallization process is hindered. Among them, the organic sodium salt forms hydrogen bonds with the end carboxyl groups of PET, and the organic nucleation inhibitor forms hydrogen bonds with the carbonyl groups in the middle of the PET chain segments. Under the action of the common hydrogen bonds, the regularity of the PET molecular chain segments decreases, the rate of nucleation decreases, and the crystallization performance of the system decreases. The lubricant macromolecules are inserted between the PET molecular chains, and through the steric effect and polar interaction, the van der Waals force and dipole-dipole effect are effectively reduced, the chain segment slip energy barrier is reduced, the chain segment activity and chain segment movement ability are improved, the glass transition temperature (Tg) is lowered, the regular arrangement of the molecular chain is destroyed, and the crystallization process is hindered. In this process, whether it is the organic sodium salt, the organic nucleation inhibitor, or the lubricating component, all of them reduce the crystallinity by destroying the regularity of the PET molecular chain segments, but the deep action mechanism is different.

[0057] The present invention also provides a refrigerator having shelves formed by injection molding the modified PET material according to any of the above-mentioned technical solutions. Currently, the main material used for shelves in the refrigerator industry is GPPS. However, due to its poor toughness and the high risk of cracking, GPPS has a quality issue. To improve cracking in refrigerator shelves while ensuring that transmittance and appearance requirements are met, the present invention controls the crystallization of PET by adding a nucleation inhibitor and a crystallization blocker during the PET modification stage. This prevents crystallization during the molding process of the refrigerator shelves, thereby ensuring the transmittance of the final product and achieving a highly transparent refrigerator shelf molded by PET.

[0058] In order to more clearly and in detail introduce the modified PET material, preparation method thereof and refrigerator provided by the embodiments of the present invention, they will be described below in conjunction with specific embodiments.

[0059] Example 1

[0060] like Figure 1 As shown, a method for preparing a low-crystallinity, high-flow PET material for refrigerator shelves comprises:

[0061] (1) Raw material formula

[0062] The raw material components were weighed according to the following weight percentages: 96.6 kg of PET plastic particles, 2 kg of nucleation inhibitor, 1 kg of lubricant, and 0.4 kg of antioxidant. The lubricant was triethyl citrate, and the antioxidant was Antioxidant 1010.

[0063] (2) Preparation of nucleation inhibition component

[0064] The nucleation inhibitor component is obtained by the following method: sodium salicylate powder and polyethylene glycol powder are pre-screened using a vibrating sieving machine to a mesh size difference of ≤50, and then pre-treated in a humidity-controlled chamber (RH ≤30%) to eliminate static electricity. Equal weights of the pre-treated sodium salicylate and polyethylene glycol powders are weighed separately and mixed using an airflow mixing system to obtain a uniform and stable powder mixture of the nucleation inhibitor component.

[0065] (3) Physical blending of raw materials

[0066] The PET plastic particles, nucleation inhibition component, lubricating component and antioxidant weighed according to the raw material formula are physically blended using a low-speed stirring device to ensure that the components of the raw materials are evenly mixed and set aside.

[0067] (4) Extrusion granulation

[0068] The weighed components were placed in a mixer, mixed at 180 r / min for 2 min, discharged, and then extruded into granules using a twin-screw extruder; the processing temperature of the twin-screw extruder was 225-255°C, the extruder included seven temperature zones, one section at 240°C, the second section at 255°C, the third section at 260°C, the fourth section at 265°C, the fifth section at 270°C, the sixth section at 280°C, and the seventh section at 285°C, and the screw speed was 550 r / min.

[0069] Example 2

[0070] like Figure 1 As shown, a method for preparing a refrigerator shelf PET material comprises:

[0071] (1) Raw material formula

[0072] The raw material components were weighed according to the following weight percentages: 98.1 kg of PET plastic particles, 1 kg of a nucleation inhibitor, 0.5 kg of a lubricating component, and 0.4 kg of an antioxidant. The lubricating component was triethyl citrate, and the antioxidant was Antioxidant 1010.

[0073] (2) Preparation of nucleation inhibition component

[0074] The nucleation inhibitor component is obtained by the following method: sodium salicylate powder and polyethylene glycol powder are pre-screened using a vibrating sieving machine to a mesh size difference of ≤50, and then pre-treated in a humidity-controlled chamber (RH ≤30%) to eliminate static electricity. Equal weights of the pre-treated sodium salicylate and polyethylene glycol powders are weighed separately and mixed using an airflow mixing system to obtain a uniform and stable powder mixture of the nucleation inhibitor component.

[0075] (3) Physical blending of raw materials

[0076] The PET plastic particles, nucleation inhibition component, lubricating component and antioxidant weighed according to the raw material formula are physically blended using a low-speed stirring device to ensure that the components of the raw materials are evenly mixed and set aside.

[0077] (4) Extrusion granulation

[0078] The weighed components were placed in a mixer, mixed at 180 r / min for 2 min, discharged, and then extruded into granules using a twin-screw extruder; the processing temperature of the twin-screw extruder was 225-255°C, the extruder included seven temperature zones, one section at 240°C, the second section at 255°C, the third section at 260°C, the fourth section at 265°C, the fifth section at 270°C, the sixth section at 280°C, and the seventh section at 285°C, and the screw speed was 550 r / min.

[0079] Example 3

[0080] like Figure 1As shown, a method for preparing a low-crystallinity, high-flow PET material for refrigerator shelves comprises:

[0081] (1) Raw material formula

[0082] The raw material components were weighed according to the following weight percentages: 96.6 kg of PET plastic particles, 2 kg of nucleation inhibitor, 1 kg of lubricant, and 0.4 kg of antioxidant. The lubricant was triethyl citrate, and the antioxidant was Antioxidant 1010.

[0083] (2) Preparation of nucleation inhibition component

[0084] The nucleation inhibitor component is obtained by the following method: sodium salicylate powder and polyethylene glycol powder are pretreated in a humidity-controlled chamber (RH ≤ 30%) to eliminate static electricity. Equal weights of the pretreated sodium salicylate and polyethylene glycol powders are then weighed and mixed using an airflow mixing system to obtain a uniform and stable powder mixture of the nucleation inhibitor component.

[0085] (3) Physical blending of raw materials

[0086] The PET plastic particles, nucleation inhibition component, lubricating component and antioxidant weighed according to the raw material formula are physically blended using a low-speed stirring device to ensure that the components of the raw materials are evenly mixed and set aside.

[0087] (4) Extrusion granulation

[0088] The weighed components were placed in a mixer, mixed at 180 r / min for 2 min, discharged, and then extruded into granules using a twin-screw extruder; the processing temperature of the twin-screw extruder was 225-255°C, the extruder included seven temperature zones, one section at 240°C, the second section at 255°C, the third section at 260°C, the fourth section at 265°C, the fifth section at 270°C, the sixth section at 280°C, and the seventh section at 285°C, and the screw speed was 550 r / min.

[0089] Example 4

[0090] like Figure 1 As shown, a method for preparing a low-crystallinity, high-flow PET material for refrigerator shelves comprises:

[0091] (1) Raw material formula

[0092] The raw material components were weighed according to the following weight percentages: 96.6 kg of PET plastic particles, 2 kg of nucleation inhibitor, 1 kg of lubricant, and 0.4 kg of antioxidant. The lubricant was triethyl citrate, and the antioxidant was Antioxidant 1010.

[0093] (2) Preparation of nucleation inhibition component

[0094] The nucleation inhibitor component is obtained by the following method: sodium salicylate powder and polyethylene glycol powder are taken, and the two powders are pre-screened using a vibrating screening machine so that the mesh size difference is ≤50. The same weight of the pretreated sodium salicylate powder and polyethylene glycol powder are weighed respectively, and the powders are mixed through an air flow mixing system to obtain a powder mixture that is a uniform and stable nucleation inhibitor component.

[0095] (3) Physical blending of raw materials

[0096] The PET plastic particles, nucleation inhibition component, lubricating component and antioxidant weighed according to the raw material formula are physically blended using a low-speed stirring device to ensure that the components of the raw materials are evenly mixed and set aside.

[0097] (4) Extrusion granulation

[0098] The weighed components were placed in a mixer, mixed at 180 r / min for 2 min, discharged, and then extruded into granules using a twin-screw extruder; the processing temperature of the twin-screw extruder was 225-255°C, the extruder included seven temperature zones, one section at 240°C, the second section at 255°C, the third section at 260°C, the fourth section at 265°C, the fifth section at 270°C, the sixth section at 280°C, and the seventh section at 285°C, and the screw speed was 550 r / min.

[0099] Example 5

[0100] like Figure 1 As shown, a method for preparing a low-crystallinity, high-flow PET material for refrigerator shelves comprises:

[0101] (1) Raw material formula

[0102] The raw material components were weighed according to the following weight percentages: 96.8 kg of PET plastic particles, 1.8 kg of a nucleation inhibitor, 1 kg of a lubricating component, and 0.4 kg of an antioxidant, wherein the lubricating component was triethyl citrate and the antioxidant was Antioxidant 1010.

[0103] (2) Preparation of nucleation inhibition component

[0104] The nucleation inhibitor component is obtained by the following method: sodium salicylate powder and polyethylene glycol powder are pre-screened using a vibrating sieving machine to a mesh size difference of ≤50, and then pre-treated in a humidity-controlled chamber (RH ≤30%) to eliminate static electricity. Equal weights of the pre-treated sodium salicylate and polyethylene glycol powders are weighed separately and mixed using an airflow mixing system to obtain a uniform and stable powder mixture of the nucleation inhibitor component.

[0105] (3) Physical blending of raw materials

[0106] The PET plastic particles, nucleation inhibition component, lubricating component and antioxidant weighed according to the raw material formula are physically blended using a low-speed stirring device to ensure that the components of the raw materials are evenly mixed and set aside.

[0107] (4) Extrusion granulation

[0108] The weighed components were placed in a mixer, mixed at 180 r / min for 2 min, discharged, and then extruded into granules using a twin-screw extruder; the processing temperature of the twin-screw extruder was 225-255°C, the extruder included seven temperature zones, one section at 240°C, the second section at 255°C, the third section at 260°C, the fourth section at 265°C, the fifth section at 270°C, the sixth section at 280°C, and the seventh section at 285°C, and the screw speed was 550 r / min.

[0109] Example 6

[0110] like Figure 1 As shown, a method for preparing a low-crystallinity, high-flow PET material for refrigerator shelves comprises:

[0111] (1) Raw material formula

[0112] The raw material components were weighed according to the following weight percentages: 97.1 kg of PET plastic particles, 1.5 kg of a nucleation inhibitor, 1 kg of a lubricating component, and 0.4 kg of an antioxidant. The lubricating component was triethyl citrate, and the antioxidant was Antioxidant 1010.

[0113] (2) Preparation of nucleation inhibition component

[0114] The nucleation inhibitor component is obtained by the following method: sodium salicylate powder and polyethylene glycol powder are pre-screened using a vibrating sieving machine to a mesh size difference of ≤50, and then pre-treated in a humidity-controlled chamber (RH ≤30%) to eliminate static electricity. Equal weights of the pre-treated sodium salicylate and polyethylene glycol powders are weighed separately and mixed using an airflow mixing system to obtain a uniform and stable powder mixture of the nucleation inhibitor component.

[0115] (3) Physical blending of raw materials

[0116] The PET plastic particles, nucleation inhibition component, lubricating component and antioxidant weighed according to the raw material formula are physically blended using a low-speed stirring device to ensure that the components of the raw materials are evenly mixed and set aside.

[0117] (4) Extrusion granulation

[0118] The weighed components were placed in a mixer, mixed at 180 r / min for 2 min, discharged, and then extruded into granules using a twin-screw extruder; the processing temperature of the twin-screw extruder was 225-255°C, the extruder included seven temperature zones, one section at 240°C, the second section at 255°C, the third section at 260°C, the fourth section at 265°C, the fifth section at 270°C, the sixth section at 280°C, and the seventh section at 285°C, and the screw speed was 550 r / min.

[0119] Example 7

[0120] like Figure 1 As shown, a method for preparing a low-crystallinity, high-flow PET material for refrigerator shelves comprises:

[0121] (1) Raw material formula

[0122] The raw material components were weighed according to the following weight percentages: 97.3 kg of PET plastic particles, 1.3 kg of nucleation inhibitor, 1 kg of lubricant, and 0.4 kg of antioxidant. The lubricant was triethyl citrate, and the antioxidant was Antioxidant 1010.

[0123] (2) Preparation of nucleation inhibition component

[0124] The nucleation inhibitor component is obtained by the following method: sodium salicylate powder and polyethylene glycol powder are pre-screened using a vibrating sieving machine to a mesh size difference of ≤50, and then pre-treated in a humidity-controlled chamber (RH ≤30%) to eliminate static electricity. Equal weights of the pre-treated sodium salicylate and polyethylene glycol powders are weighed separately and mixed using an airflow mixing system to obtain a uniform and stable powder mixture of the nucleation inhibitor component.

[0125] (3) Physical blending of raw materials

[0126] The PET plastic particles, nucleation inhibition component, lubricating component and antioxidant weighed according to the raw material formula are physically blended using a low-speed stirring device to ensure that the components of the raw materials are evenly mixed and set aside.

[0127] (4) Extrusion granulation

[0128] The weighed components were placed in a mixer, mixed at 180 r / min for 2 min, discharged, and then extruded into granules using a twin-screw extruder; the processing temperature of the twin-screw extruder was 225-255°C, the extruder included seven temperature zones, one section at 240°C, the second section at 255°C, the third section at 260°C, the fourth section at 265°C, the fifth section at 270°C, the sixth section at 280°C, and the seventh section at 285°C, and the screw speed was 550 r / min.

[0129] Example 8

[0130] like Figure 1As shown, a method for preparing a low-crystallinity, high-flow PET material for refrigerator shelves comprises:

[0131] (1) Raw material formula

[0132] The raw material components were weighed according to the following weight percentages: 96.8 kg of PET plastic particles, 2 kg of nucleation inhibitor, 0.8 kg of lubricant, and 0.4 kg of antioxidant. The lubricant was triethyl citrate, and the antioxidant was antioxidant 1010.

[0133] (2) Preparation of nucleation inhibition component

[0134] The nucleation inhibitor component is obtained by the following method: sodium salicylate powder and polyethylene glycol powder are pre-screened using a vibrating sieving machine to a mesh size difference of ≤50, and then pre-treated in a humidity-controlled chamber (RH ≤30%) to eliminate static electricity. Equal weights of the pre-treated sodium salicylate and polyethylene glycol powders are weighed separately and mixed using an airflow mixing system to obtain a uniform and stable powder mixture of the nucleation inhibitor component.

[0135] (3) Physical blending of raw materials

[0136] The PET plastic particles, nucleation inhibition component, lubricating component and antioxidant weighed according to the raw material formula are physically blended using a low-speed stirring device to ensure that the components of the raw materials are evenly mixed and set aside.

[0137] (4) Extrusion granulation

[0138] The weighed components were placed in a mixer, mixed at 180 r / min for 2 min, discharged, and then extruded into granules using a twin-screw extruder; the processing temperature of the twin-screw extruder was 225-255°C, the extruder included seven temperature zones, one section at 240°C, the second section at 255°C, the third section at 260°C, the fourth section at 265°C, the fifth section at 270°C, the sixth section at 280°C, and the seventh section at 285°C, and the screw speed was 550 r / min.

[0139] Example 9

[0140] like Figure 1 As shown, a method for preparing a low-crystallinity, high-flow PET material for refrigerator shelves comprises:

[0141] (1) Raw material formula

[0142] The raw material components were weighed according to the following weight percentages: 97.0 kg of PET plastic particles, 2 kg of nucleation inhibitor, 0.6 kg of lubricant, and 0.4 kg of antioxidant. The lubricant was triethyl citrate, and the antioxidant was antioxidant 1010.

[0143] (2) Preparation of nucleation inhibition component

[0144] The nucleation inhibitor component is obtained by the following method: sodium salicylate powder and polyethylene glycol powder are pre-screened using a vibrating sieving machine to a mesh size difference of ≤50, and then pre-treated in a humidity-controlled chamber (RH ≤30%) to eliminate static electricity. Equal weights of the pre-treated sodium salicylate and polyethylene glycol powders are weighed separately and mixed using an airflow mixing system to obtain a uniform and stable powder mixture of the nucleation inhibitor component.

[0145] (3) Physical blending of raw materials

[0146] The PET plastic particles, nucleation inhibition component, lubricating component and antioxidant weighed according to the raw material formula are physically blended using a low-speed stirring device to ensure that the components of the raw materials are evenly mixed and set aside.

[0147] (4) Extrusion granulation

[0148] The weighed components were placed in a mixer, mixed at 180 r / min for 2 min, discharged, and then extruded into granules using a twin-screw extruder; the processing temperature of the twin-screw extruder was 225-255°C, the extruder included seven temperature zones, one section at 240°C, the second section at 255°C, the third section at 260°C, the fourth section at 265°C, the fifth section at 270°C, the sixth section at 280°C, and the seventh section at 285°C, and the screw speed was 550 r / min.

[0149] Comparative Example 1

[0150] A method for preparing a refrigerator shelf PET material, comprising:

[0151] (1) Raw material formula

[0152] The raw material components were weighed according to the following weight percentages: 97.6 kg of PET plastic particles, 2 kg of nucleation inhibitor component, and 0.4 kg of antioxidant, wherein the antioxidant was antioxidant 1010.

[0153] (2) Preparation of nucleation inhibition component

[0154] The nucleation inhibitor component is obtained by the following method: sodium salicylate powder and polyethylene glycol powder are pre-screened using a vibrating sieving machine to a mesh size difference of ≤50, and then pre-treated in a humidity-controlled chamber (RH ≤30%) to eliminate static electricity. Equal weights of the pre-treated sodium salicylate and polyethylene glycol powders are weighed separately and mixed using an airflow mixing system to obtain a uniform and stable powder mixture of the nucleation inhibitor component.

[0155] (3) Physical blending of raw materials

[0156] The PET plastic particles, nucleation inhibitor components and antioxidants weighed according to the raw material formula are physically blended using a low-speed stirring device to ensure that the components of the raw materials are evenly mixed and set aside.

[0157] (4) Extrusion granulation

[0158] The weighed components were placed in a mixer, mixed at 180 r / min for 2 min, discharged, and then extruded into granules using a twin-screw extruder; the processing temperature of the twin-screw extruder was 225-255°C, the extruder included seven temperature zones, one section at 240°C, the second section at 255°C, the third section at 260°C, the fourth section at 265°C, the fifth section at 270°C, the sixth section at 280°C, and the seventh section at 285°C, and the screw speed was 550 r / min.

[0159] Comparative Example 2

[0160] A method for preparing a refrigerator shelf PET material, comprising:

[0161] (1) Raw material formula

[0162] The raw material components were weighed according to the following weight percentages: 98.6 kg of PET plastic particles, 0 kg of nucleation inhibitor, 1 kg of lubricant, and 0.4 kg of antioxidant. The lubricant was triethyl citrate, and the antioxidant was Antioxidant 1010.

[0163] (2) Physical blending of raw materials

[0164] The PET plastic particles, lubricating components and antioxidants weighed according to the raw material formula are physically blended using a low-speed stirring device to ensure that the components of the raw materials are evenly mixed and set aside.

[0165] (3) Extrusion granulation

[0166] The weighed components were placed in a mixer, mixed at 180 r / min for 2 min, discharged, and then extruded into granules using a twin-screw extruder; the processing temperature of the twin-screw extruder was 225-255°C, the extruder included seven temperature zones, one section at 240°C, the second section at 255°C, the third section at 260°C, the fourth section at 265°C, the fifth section at 270°C, the sixth section at 280°C, and the seventh section at 285°C, and the screw speed was 550 r / min.

[0167] Comparative Example 3

[0168] A method for preparing a refrigerator shelf PET material, comprising:

[0169] (1) Raw material formula

[0170] The raw material components were weighed according to the following weight percentages: 99.6 kg of PET plastic particles and 0.4 kg of antioxidant, wherein the antioxidant was antioxidant 1010.

[0171] (2) Physical blending of raw materials

[0172] The PET plastic particles and antioxidants weighed according to the raw material formula are physically blended using a low-speed stirring device to ensure that the components of the raw materials are evenly mixed and set aside.

[0173] (3) Extrusion granulation

[0174] The weighed components were placed in a mixer, mixed at 180 r / min for 2 min, discharged, and then extruded into granules using a twin-screw extruder; the processing temperature of the twin-screw extruder was 225-255°C, the extruder included seven temperature zones, one section at 240°C, the second section at 255°C, the third section at 260°C, the fourth section at 265°C, the fifth section at 270°C, the sixth section at 280°C, and the seventh section at 285°C, and the screw speed was 550 r / min.

[0175] Comparative Example 4

[0176] like Figure 1 As shown, a method for preparing a refrigerator shelf PET material comprises:

[0177] (1) Raw material formula

[0178] The raw material components were weighed according to the following weight percentages: 96.6 kg of PET plastic particles, 2 kg of nucleation inhibitor, 1 kg of lubricant, and 0.4 kg of antioxidant. The lubricant was triethyl citrate, and the antioxidant was Antioxidant 1010.

[0179] (2) Preparation of nucleation inhibition component (using only sodium salicylate)

[0180] The nucleation inhibitor component is obtained by the following method: sodium salicylate powder is pre-screened using a vibrating sieving machine to a mesh size difference of ≤50, and then pre-treated in a humidity-controlled chamber (RH ≤30%) to eliminate static electricity. The pre-treated sodium salicylate powder is weighed and mixed using an airflow mixing system to obtain a uniform and stable nucleation inhibitor component.

[0181] (3) Physical blending of raw materials

[0182] The PET plastic particles, nucleation inhibition component, lubricating component and antioxidant weighed according to the raw material formula are physically blended using a low-speed stirring device to ensure that the components of the raw materials are evenly mixed and set aside.

[0183] (4) Extrusion granulation

[0184] The weighed components were placed in a mixer, mixed at 180 r / min for 2 min, discharged, and then extruded into granules using a twin-screw extruder; the processing temperature of the twin-screw extruder was 225-255°C, the extruder included seven temperature zones, one section at 240°C, the second section at 255°C, the third section at 260°C, the fourth section at 265°C, the fifth section at 270°C, the sixth section at 280°C, and the seventh section at 285°C, and the screw speed was 550 r / min.

[0185] Comparative Example 5

[0186] like Figure 1 As shown, a method for preparing a refrigerator shelf PET material comprises:

[0187] (1) Raw material formula

[0188] The raw material components were weighed according to the following weight percentages: 96.6 kg of PET plastic particles, 2 kg of nucleation inhibitor, 1 kg of lubricant, and 0.4 kg of antioxidant. The lubricant was triethyl citrate, and the antioxidant was Antioxidant 1010.

[0189] (2) Preparation of nucleation inhibitory component (using only polyethylene glycol)

[0190] The nucleation inhibitor component is obtained by the following method: polyethylene glycol powder is pre-screened using a vibrating sieving machine to a mesh size difference of ≤50, and then pre-treated in a humidity-controlled chamber (RH ≤30%) to eliminate static electricity. The pre-treated polyethylene glycol powder is weighed and mixed using an airflow mixing system to obtain a uniform and stable powder mixture of the nucleation inhibitor component.

[0191] (3) Physical blending of raw materials

[0192] The PET plastic particles, nucleation inhibition component, lubricating component and antioxidant weighed according to the raw material formula are physically blended using a low-speed stirring device to ensure that the components of the raw materials are evenly mixed and set aside.

[0193] (4) Extrusion granulation

[0194] The weighed components were placed in a mixer, mixed at 180 r / min for 2 min, discharged, and then extruded into granules using a twin-screw extruder; the processing temperature of the twin-screw extruder was 225-255°C, the extruder included seven temperature zones, one section at 240°C, the second section at 255°C, the third section at 260°C, the fourth section at 265°C, the fifth section at 270°C, the sixth section at 280°C, and the seventh section at 285°C, and the screw speed was 550 r / min.

[0195] Performance Testing

[0196] The formulations of the embodiments and comparative examples are shown in Table 1.

[0197] Table 1 Formula composition of the embodiment and comparative example

[0198]

[0199] The performance tests were performed on the PET materials obtained in the examples and comparative examples, and the test standards are shown in Table 2.

[0200] Table 2 Test standards

[0201] Test items Test standards <![CDATA[Melt index / g·min -1 > ASTM 1238 275℃ 2.16kg Tensile strength / MPa ASTM D638 Bending strength / MPa ASTM D790 Flexural modulus / MPa ASTM D790 <![CDATA[Izod / J·m -1 ]]> ASTM D256 Vicat / ℃ ASTM D648 Thermal crystallization temperature / ℃ tc' Subcooling temperature / ℃ tm-tc' Overheat temperature / ℃ tc–tg Apparent crystallization temperature range / ℃ tc'-tc

[0202] The performance tests of the PET materials obtained in the examples and comparative examples were carried out according to the test standards in Table 2. The test results are shown in Tables 3 and 4.

[0203] Table 3 Performance test results

[0204]

[0205] Table 4 Performance test results

[0206]

[0207] Table 5 shows the performance requirements of the refrigerator shelf body for the PET material, the performance of the existing GPPS material used for the refrigerator shelf body, and the performance of the modified PET materials obtained in Examples 1 and 2 of the present invention.

[0208] Table 5 Performance requirements of PET materials for refrigerator shelf body

[0209]

[0210] The present invention improves the fluidity of PET materials and reduces the crystallization performance of PET materials by adding nucleation inhibition components and lubricating components. The parameter indicators for evaluating the two performances are carried out through melt index and crystallization parameters such as thermal crystallization temperature, supercooling temperature, overheating temperature, and apparent crystallization temperature, and the advancement of the technical solution is comprehensively evaluated. From the parameter analysis: the decrease in thermal crystallization temperature, the increase in supercooling temperature, the increase in overheating temperature, and the decrease in apparent crystallization temperature reflect the decrease in crystallization ability, such as Figure 5 、 6 As shown, compared with Comparative Example 3, Example 1 has a lower thermal crystallization temperature of 30°C, an increased supercooling temperature of 32°C, an increased superheating temperature of 9°C, and a lower apparent crystallization temperature of 48°C. At the same time, the fluidity is increased by 50%. The final product has good transparency and meets the use requirements.

Claims

1. A modified PET material, characterized in that, The raw materials are extruded and granulated, and the raw materials include: PET plastic particles, nucleation inhibition components and lubricating components; The nucleation inhibition component includes a carboxyl-containing organic metal salt and an organic nucleation inhibitor, wherein the organic nucleation inhibitor is selected from polyethylene glycol derivatives; the polyethylene glycol derivative is selected from at least one of polyethylene glycol, carboxylic acid polyethylene glycol, hydroxy-polyethylene glycol-carboxylic acid, and maleimide-polyethylene glycol-hydroxyl; The lubricating component is selected from at least one of triethyl citrate, acetyl tributyl citrate, dioctyl phthalate, dibutyl phthalate, and sorbitol hexabenzoate.

2. The modified PET material according to claim 1, characterized in that In parts by weight, the amount of the PET plastic particles is selected from any value between 96.6 and 98.1 parts, the amount of the nucleation inhibition component is selected from any value between 1 and 2 parts, and the amount of the lubricating component is selected from any value between 0.5 and 1 part.

3. The modified PET material according to claim 1, characterized in that The organic metal salt is selected from at least one of sodium acetate, sodium formate, sodium citrate, potassium citrate, sodium benzoate, and sodium salicylate.

4. The modified PET material according to claim 1, characterized in that The nucleation inhibition component is obtained by the following method: the organic metal salt with a mesh size difference of ≤50 and the organic nucleation inhibitor are firstly subjected to static elimination and then uniformly mixed to obtain the nucleation inhibition component.

5. The modified PET material according to claim 2, characterized in that The raw materials further include an antioxidant, and the amount of the antioxidant is selected from any value between 0.1 and 0.4 parts.

6. The modified PET material according to claim 5, characterized in that The antioxidant is selected from at least one of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol, β-(-4-hydroxy-3,5-di-tert-butylphenyl)propionate, tris(2,4-di-tert-butylphenyl) phosphite, and 3,9-bis(2,4-di-tert-butylphenoxy)-2,4,8,10-tetraoxo-3,9-diphosphabicyclo[5.5]undecane.

7. The modified PET material according to claim 1, characterized in that The PET plastic particles are polyethylene terephthalate, have an intrinsic viscosity of 0.810 dL / g, an acetaldehyde content of less than 0.5 μg / g, a terminal carboxyl content of less than 30 ppm, a chromaticity b value of ≤1.0, and an L value of ≥80.

8. The method for preparing the modified PET material according to any one of claims 1 to 7, characterized in that: The raw materials are extruded into granules through a twin-screw extruder; the processing temperature of the twin-screw extruder is 260-285° C.; and the screw speed is 450-650 r / min.

9. The method for preparing the modified PET material according to claim 8, wherein: During the extrusion granulation process, the organic metal salt is hydrogen bonded to the terminal carboxyl group of the molten PET, and the terminal hydroxyl group of the polyethylene glycol derivative is hydrogen bonded to the carbonyl group in the middle of the PET chain segment. Under the dual action of the organic metal salt and the polyethylene glycol derivative, the regularity of the PET molecular chain segment is reduced, and the crystallization ability of the PET molecule is reduced. At the same time, the lubricating component is inserted between the PET molecular chains, and through steric hindrance and polar interaction, the van der Waals force and dipole-dipole effect are reduced, so that the chain segment slip energy barrier is reduced, the chain segment activity and chain segment movement ability are improved, the glass transition temperature is reduced, the regular arrangement of the molecular chain is destroyed, and the crystallization process is hindered.

10. A refrigerator, characterized in that: The shelf of the refrigerator is obtained by injection molding the modified PET material according to any one of claims 1 to 7.

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