Regenerated polyethylene glycol terephthalate material as well as preparation method and application thereof

Abstract

The invention provides a regenerated polyethylene glycol terephthalate material as well as a preparation method and application thereof, and belongs to the technical field of modification of waste polyethylene glycol terephthalate. The waste polyethylene glycol terephthalate (PET) is modified by polyethylene terephthalate-1, 4-cyclohexanedimethanol (PETG), the toughness of the PETG is good, the toughness, impact resistance and the like of the waste PET can be remarkably improved after the PETG is blended with the waste PET, the melt viscosity of the PETG is relatively low, the melt viscosity of a whole blending system can be reduced after the PETG is blended with the waste PET, and the toughness, impact resistance and the like of the waste PET are improved. According to the present invention, the modified waste PET is adopted as the raw material, such that the processability of the waste PET is easily achieved, the performance of the modified waste PET is improved, the modified waste PET is blended with the fresh PET so as to easily achieve the recycling of the PET material, the prepared regenerated polyethylene glycol terephthalate material has characteristics of high light transmittance, high heat resistance temperature and moderate melt index, and the mechanical properties can meet the use requirements.

Description

Technical Field

[0001] The invention relates to the technical field of waste polyethylene terephthalate modification, and in particular to a recycled polyethylene terephthalate material and a preparation method and application thereof. Background Art

[0002] Polyethylene terephthalate (PET) plastic is the most widely used packaging material today. Whether in food, medical or chemical industries, polyethylene terephthalate (PET) plastic will not be corroded when used in liquids with strong acidity and alkalinity, and its toughness and brittleness can also remain stable. Therefore, it is widely used in packaging materials and other fields. Due to the large-scale use of PET materials, the volume of waste PET plastics has gradually increased. The treatment methods of waste PET plastics include landfill and incineration, but they will damage the soil and the environment. The incinerated PET plastics will also cause damage and pollution to human health and the environment. Therefore, the best way to deal with waste PET plastics is recycling and reuse, that is, using physical methods to reprocess waste PET plastics into useful products, so that they can enter the market again as new products. This method is relatively simple and has a low investment cost. It is currently a common method for recycling waste PET plastics. However, most recycled waste PET plastics have poor performance and cannot be used directly. Therefore, it is particularly important to modify waste plastics on the basis of simple recycling.

[0003] CN103497492B discloses a PET material modified by viscosity enhancement of waste bottle flakes, which uses waste PET bottle flakes as raw materials, adds a chain extender and a nucleating agent, and then extrudes the PET through an extruder to increase the viscosity of the PET. By changing the formula ratio, PET materials with different viscosities can be obtained.

[0004] CN111138697A discloses a method for preparing PET film using waste PET materials. The invention uses waste PET as the basic raw material, and uses a mixed solvent to dissolve it and remove impurities. Then, the mixture undergoes a preliminary reaction to form a trace amount of new PET, which is combined with the waste PET. Under high temperature and high pressure, it is degraded to reduce the molecular weight and form a small molecule PET. At the same time, an auxiliary agent is used to generate gas, so that the new PET can enter the waste, and then silane polymerization is used to form a polymer to modify it and increase its performance. Finally, a catalyst is used to form a large molecule PET to improve its performance.

[0005] The performance of waste PET plastics is far different from that of new PET plastics. Therefore, during processing, additives need to be added to waste PET plastics to improve their performance. The modified waste PET plastics can meet their application in food, medical, chemical and other fields. However, a large amount of additives added to waste PET plastics will affect the original transparency of PET plastics. In addition, the color of waste PET plastics is white or yellowish, and the transparency is low. Therefore, the selection of additives needs to adapt to the processing conditions and effects of PET plastics.

[0006] In addition, affected by the application fields of PET plastics, PET plastics require higher heat resistance, while pure PET plastics have low heat resistance, which can only reach about 60-70°C. At the same time, the modified waste PET plastics may be affected by the shape of the manufacturing mold, processing conditions and other aspects in terms of brittleness, toughness and processing performance during the subsequent processing. Therefore, the subsequent processing must also be considered during the modification of waste PET plastics.

[0007] In summary, waste PET plastics can be modified to improve their impact strength, rigidity, flexibility and other properties, and then applied to different fields. However, due to the limitations of modification conditions, the impact properties of waste polystyrene materials cannot be further improved and there is an upper limit, and the transparency of PET plastics is affected. At the same time, the heat resistance of waste PET plastics is generally low, which is still a problem that needs to be solved urgently. Summary of the invention

[0008] In view of the above problems, the present invention provides a recycled polyethylene terephthalate material, a preparation method and application thereof. The recycled polyethylene terephthalate material is prepared by utilizing waste polyethylene terephthalate (PET) material, modifying it with polyethylene terephthalate-1,4-cyclohexanedimethanol (PETG) and an antioxidant, and then mixing it with fresh polyethylene terephthalate in a certain ratio. After the recycled polyethylene terephthalate material is made into a product by a blow molding device, the product has good impact resistance, high transparency, good toughness and good heat resistance. At the same time, the problem of accumulation of waste polyethylene terephthalate materials is solved, and the product is green, environmentally friendly and efficient.

[0009] The invention provides a recycled polyethylene terephthalate material. The recycled polyethylene terephthalate material is prepared by modifying waste polyethylene terephthalate with polyethylene terephthalate-1,4-cyclohexanedimethanol ester and an antioxidant in a molten state, and then melt-mixing with fresh polyethylene terephthalate. The light transmittance of the recycled polyethylene terephthalate material is 90-95%, the cantilever beam notched impact strength of the recycled polyethylene terephthalate material is 33-37.5 J / m, the tensile strength is 50-56 MPa, the elongation at break is 17-21%, the melt index of the recycled polyethylene terephthalate material is 12.9-22.2 g / min at 275° C. and a load of 2.16 kg, and the heat resistance temperature of the recycled polyethylene terephthalate material is 82-89° C.

[0010] Furthermore, the mass ratio of the waste polyethylene terephthalate to the polyethylene terephthalate-1,4-cyclohexanedimethanol ester is (1:1.2)-(1:2).

[0011] Furthermore, the mass ratio of the waste polyethylene terephthalate to the fresh polyethylene terephthalate is (1:1)-(1:2).

[0012] Furthermore, the tensile strength of the waste polyethylene terephthalate is 32 MPa, the elongation at break is 1-3%, and the melt index of the waste polyethylene terephthalate is 13.8 g / min at 275° C. and a load of 2.16 kg.

[0013] Furthermore, the notched cantilever impact strength of the polyethylene terephthalate-1,4-cyclohexanedimethanol ester is 7.9 J / m, the elongation at break is 120-150%, and the melt index of the polyethylene terephthalate-1,4-cyclohexanedimethanol ester is 15.3 g / min at 275° C. and a load of 2.16 kg.

[0014] Furthermore, the fresh polyethylene terephthalate has an Izod notched impact strength of 68.6 J / m, an elongation at break of 2-3%, and a melt index of 27.3 cm at 275°C and a load of 2.16 kg. 3 / 10min.

[0015] Furthermore, the antioxidant is a compound of an alcohol ester antioxidant and a phosphite antioxidant in a mass ratio of 2:1.

[0016] Furthermore, the alcohol ester antioxidant is one or more of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (antioxidant 1010), β-(3,5-di-tert-butyl, 4-hydroxyphenyl) propionate octadecyl alcohol (antioxidant 1076), and 2,6-di-tert-butyl-p-cresol (antioxidant 264).

[0017] Furthermore, the phosphite antioxidant is one or more of tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168) and bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite (antioxidant 626).

[0018] The present invention also provides a method for preparing the recycled polyethylene terephthalate material, comprising the following steps: Step 1, mixing waste polyethylene terephthalate, polyethylene terephthalate-1,4-cyclohexanedimethanol and an antioxidant in a high-speed mixer, adding the mixture into a twin-screw extruder, heating and mixing, and pelletizing to obtain a mixed masterbatch; Step 2: After mixing the mixed masterbatch and fresh polyethylene terephthalate in a high-speed mixer, adding the mixture into a twin-screw extruder for melt blending, extruding and pelletizing to obtain the recycled polyethylene terephthalate material.

[0019] Furthermore, in the step 1, the mass ratio of the waste polyethylene terephthalate, the polyethylene terephthalate-1,4-cyclohexanedimethanol ester and the antioxidant is (1:1.2:0.003)-(1:2:0.003).

[0020] Furthermore, the tensile strength of the waste polyethylene terephthalate is 20-40 MPa, the elongation at break is 1-3%, and the melt index of the waste polyethylene terephthalate is 5-20 g / min at 275° C. and a load of 2.16 kg.

[0021] Furthermore, the notched cantilever impact strength of the polyethylene terephthalate-1,4-cyclohexanedimethanol ester is 7.9 J / m, the elongation at break is 120-150%, and the melt index of the polyethylene terephthalate-1,4-cyclohexanedimethanol ester is 15.3 g / min at 275° C. and a load of 2.16 kg.

[0022] Furthermore, the antioxidant in step 1 is a compound of an alcohol ester antioxidant and a phosphite antioxidant in a mass ratio of 2:1.

[0023] Furthermore, the alcohol ester antioxidant is one or more of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (antioxidant 1010), β-(3,5-di-tert-butyl, 4-hydroxyphenyl) propionate octadecyl alcohol (antioxidant 1076), and 2,6-di-tert-butyl-p-cresol (antioxidant 264).

[0024] Furthermore, the phosphite antioxidant is one or more of tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168) and bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite (antioxidant 626).

[0025] Furthermore, in step 1, the rotation speed of the high-speed mixer is 300-500 r / min, and the mixing time of the high-speed mixer is 5-10 min.

[0026] Furthermore, the heating and mixing temperature in step 1 is 240-270°C, divided into 5 temperature zones, wherein the first temperature zone is 240°C, the second temperature zone is 260°C, the third temperature zone is 270°C, the fourth temperature zone is 270°C, and the fifth temperature zone is 250°C.

[0027] Furthermore, the mass ratio of the fresh polyethylene terephthalate in step 2 to the waste polyethylene terephthalate in step 1 is (1:1)-(2:1).

[0028] Furthermore, the fresh polyethylene terephthalate in step 2 has an Izod notched impact strength of 68.6 J / m, an elongation at break of 2-3%, and a melt index of 27.3 cm at 275° C. and a load of 2.16 kg. 3 / 10min.

[0029] Furthermore, in step 2, the rotation speed of the high-speed mixer is 300-500 r / min, and the mixing time of the high-speed mixer is 5-10 min.

[0030] Furthermore, the processing temperature of the twin-screw extruder in step 2 is 240-300°C, divided into five temperature zones, wherein the temperature of the first temperature zone is 240°C, the temperature of the second temperature zone is 260°C, the temperature of the third temperature zone is 280°C, the temperature of the fourth temperature zone is 300°C, and the temperature of the fifth temperature zone is 280°C.

[0031] The present invention also provides a plastic bottle, which is prepared by blow molding the recycled polyethylene terephthalate material through a blow molding mold with a coating; the thickness of the plastic bottle is 0.5-1 mm; the light transmittance of the plastic bottle is 90-95%, the heat resistance temperature of the plastic bottle is 85-95°C, and the water vapor barrier property of the plastic bottle is 3.5-4.8 g·mm / mm 2 ·d·kPa, oxygen barrier property is 71-103cm 3 mm / m 2 ·d·MPa.

[0032] The present invention also provides a method for preparing the plastic bottle, comprising the following steps: Step 1, adding the recycled polyethylene terephthalate material into an injection molding machine, melting it into a mold in the injection molding machine, and obtaining a bottle embryo; Step 2: preheat the bottle embryo with a heating lamp, put it into a blow molding mold with a coating, and blow mold it, and cool it to obtain the plastic bottle.

[0033] Furthermore, the heating temperature of the injection molding machine in step 1 is 240-300°C, which is divided into five temperature zones from left to right, wherein the temperature of the first temperature zone is 240°C, the temperature of the second temperature zone is 260°C, the temperature of the third temperature zone is 280°C, the temperature of the fourth temperature zone is 300°C and the temperature of the fifth temperature zone is 280°C.

[0034] Furthermore, the preheating temperature in step 2 is 180-190° C., and the preheating time is 3-5 min.

[0035] Furthermore, in step 2, the coating is polytetrafluoroethylene, and the thickness of the coating is 0.03-0.05 mm.

[0036] Furthermore, the heating temperature of the blow molding mold in step 2 is 140°C.

[0037] Furthermore, the blow mold in step 2 includes a left module, a right module and a bottom module.

[0038] Further, the coating is located on a bottom module of the blow mold.

[0039] Furthermore, the cooling method in step 2 is to introduce medium-pressure compressed air into the bottle embryo, and the pressure of the medium-pressure compressed air is 3.2 MPa.

[0040] Furthermore, in the blow molding mold at 140° C., the molecular chains of the recycled polyethylene terephthalate material are partially rearranged to form spherical crystals.

[0041] Beneficial effects of the present invention: 1. The present invention modifies waste polyethylene terephthalate (PET) by polyethylene terephthalate-1,4-cyclohexanedimethanol (PETG). PETG has good toughness, and the flexible structural unit in the molecular chain can effectively transmit and disperse external forces. After being blended with waste PET, the toughness and impact resistance of waste PET can be significantly improved. At the same time, the processing performance, heat-resistant temperature and transparency of waste PET are reduced due to heat treatment and repeated use, while the melt viscosity of PETG is relatively low. After being blended with waste PET, the melt viscosity of the entire blending system can be reduced, which is beneficial to the processability of waste PET. During the injection molding or extrusion process, the fluidity of the blended material is better, and the mold cavity can be filled more smoothly or passed through the extruder head. In addition, the transparency and heat resistance of PETG are also higher, and the waste PET is "neutralized" to improve the physical properties of the waste PET. In the present invention, the amount of fresh PET added is reduced by adding PETG; 2. In the present invention, the blending process of PETG and waste PET is carried out in a twin-screw extruder at a specific temperature, so that the materials are subjected to shearing, extrusion and the like in a closed system, thereby being melt-mixed. The shearing and mixing effects on the materials are relatively uniform, so that PETG, waste PET and antioxidant can be better dispersed and blended. At the same time, the specific temperature of the twin-screw extruder is used to make the materials better mixed. Too low a temperature will result in insufficient mixing of the materials, while too high a temperature will cause the waste PET to decompose. 3. The recycled polyethylene terephthalate material prepared in the present invention is prepared by blending modified waste PET with fresh PET. The modified waste PET has improved performance and is blended with fresh PET, which helps to realize the recycling of PET materials and reduce dependence on original petroleum resources. The prepared recycled polyethylene terephthalate material has high light transmittance and heat resistance temperature, moderate melt index, and mechanical properties that can meet the use requirements. The antioxidant can maintain the material's yellowing resistance and antioxidant properties during use. Due to the presence of waste PET, when no antioxidant is used, the yellowing ratio of the material is high and cannot meet the use requirements. 4. The present invention also prepares plastic bottles by using recycled polyethylene terephthalate materials. In the conventional plastic bottle preparation process, in order to increase the heat resistance temperature of the material bottle, the heating temperature of the mold usually needs to be increased, which causes the plastic bottle to be drawn or adhered to the mold during demolding, resulting in the phenomenon that the bottle body is damaged. The present invention solves the adhesion problem between the bottle body and the mold by arranging a coating in the blow molding mold. Conventional coatings such as talcum powder and other materials, as coatings, will cause the light transmittance or transparency of the plastic bottle to drop sharply due to the high haze of the material itself. Therefore, the selection of the coating is also the focus of the present invention. At the same time, as a coating, when applied on the blow molding mold, if the thickness is too thin, it will not have an anti-sticking effect, and the coating will be stuck to the bottle body due to repeated use, and if the thickness is too thick, the coating will not be successfully applied. The present invention achieves excellent bottle making effect by using a specific coating and thickness in the preparation process of the plastic bottle of the present invention; 5. In the present invention, the heating temperature of the preform in the blow molding mold is 140°C. At this time, the molecular chains of polyethylene terephthalate are partially rearranged to form spherical crystals, which increases the heat shrinkage deformation temperature of the recycled polyethylene terephthalate material and maintains its strength and transparency. In the present invention, the processing temperature of the preform is increased. In order to prevent the plastic bottles from sticking and cool the plastic bottles, the blow molding module is usually cooled rapidly to cool the plastic bottles and demold them. However, this situation will increase the brittleness of the plastic bottles and deteriorate their compressive performance. The present invention cools the plastic bottles by continuously blowing high-pressure gas, thereby maintaining the mechanical properties of the plastic bottles. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a structural schematic diagram of the blow molding process of the blow molding mold described in the present invention; Figure 2 It is a cross-sectional view of the bottom module of the blow mold described in the present invention. DETAILED DESCRIPTION

[0043] The invention is described in detail below with reference to the embodiments: The invention provides a recycled polyethylene terephthalate material and a preparation method and application thereof. The recycled polyethylene terephthalate material is prepared by modifying waste polyethylene terephthalate (PET) with polyethylene terephthalate-1,4-cyclohexanedimethanol (PETG) and blending the recycled polyethylene terephthalate material with fresh PET. The material has high light transmittance and heat resistance temperature, moderate melt index, and mechanical properties that can meet use requirements, thereby greatly improving its application in the fields of packaging or plastics.

[0044] Example 1 The present embodiment provides a recycled polyethylene terephthalate material, wherein the recycled polyethylene terephthalate material is prepared by modifying waste polyethylene terephthalate with polyethylene terephthalate-1,4-cyclohexanedimethanol ester and an antioxidant in a molten state, and then melt-mixing with fresh polyethylene terephthalate; the light transmittance of the recycled polyethylene terephthalate material is 93%, the cantilever beam notched impact strength of the recycled polyethylene terephthalate material is 33.0 J / m, the tensile strength is 50 MPa, and the elongation at break is 19%. At 275°C and a load of 2.16 kg, the melt index of the recycled polyethylene terephthalate material is 13.7 g / min, and the heat resistance temperature of the recycled polyethylene terephthalate material is 82°C.

[0045] In this embodiment, the mass ratio of the waste polyethylene terephthalate to the polyethylene terephthalate-1,4-cyclohexanedimethanol ester is 1:1.2; The mass ratio of the waste polyethylene terephthalate to the fresh polyethylene terephthalate is 1:2; The tensile strength of the waste polyethylene terephthalate is 32 MPa, the elongation at break is 3%, and the melt index of the waste polyethylene terephthalate is 13.8 g / min at 275° C. and a load of 2.16 kg; The polyethylene terephthalate-1,4-cyclohexanedimethanol ester has an Izod notched impact strength of 7.9 J / m, an elongation at break of 130%, and a melt index of 15.3 g / min at 275° C. and a load of 2.16 kg; The fresh polyethylene terephthalate has an Izod notched impact strength of 68.6 J / m and an elongation at break of 3%. At 275°C and a load of 2.16 kg, the melt index of the fresh polyethylene terephthalate is 27.3 cm 3 / 10min; The antioxidant is a compound of an alcohol ester antioxidant and a phosphite antioxidant in a mass ratio of 2:1; The alcohol ester antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (antioxidant 1010), and the phosphite antioxidant is tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168); The mass ratio of the waste polyethylene terephthalate, the polyethylene terephthalate-1,4-cyclohexanedimethanol ester and the antioxidant is 1:1.2:0.003.

[0046] This embodiment also provides a method for preparing the recycled polyethylene terephthalate material, comprising the following steps: Step 1, mixing waste polyethylene terephthalate, polyethylene terephthalate-1,4-cyclohexanedimethanol ester and an antioxidant in a high-speed mixer at 500r / min for 5min, adding the mixture into a twin-screw extruder, wherein the processing temperature of the twin-screw extruder is 240-270°C, and the mixture is divided into five temperature zones, wherein the first temperature zone is 240°C, the second temperature zone is 260°C, the third temperature zone is 270°C, the fourth temperature zone is 270°C, and the fifth temperature zone is 250°C, and pelletizing is performed to obtain a mixed masterbatch; Step 2: After mixing the mixed masterbatch and fresh polyethylene terephthalate in a high-speed mixer at 500 r / min for 5 minutes, adding the mixture into a twin-screw extruder for melt blending, extruding and pelletizing to obtain the recycled polyethylene terephthalate material. The processing temperature of the twin-screw extruder is 240-300°C, which is divided into five temperature zones, wherein the temperature of the first temperature zone is 240°C, the temperature of the second temperature zone is 260°C, the temperature of the third temperature zone is 280°C, the temperature of the fourth temperature zone is 300°C, and the temperature of the fifth temperature zone is 280°C.

[0047] This embodiment also provides a plastic bottle, which is made by blow molding the recycled polyethylene terephthalate material through a blow molding mold with a coating; the thickness of the plastic bottle is 0.5 mm; the light transmittance of the plastic bottle is 95%, the heat resistance temperature of the plastic bottle is 87° C., and the water vapor barrier property of the plastic bottle is 3.6 g·mm / mm 2 ·d·kPa, oxygen barrier property is 81cm 3 mm / m 2 ·d·MPa.

[0048] This embodiment also provides a method for preparing a plastic bottle, comprising the following steps: Step 1, adding the recycled polyethylene terephthalate material into an injection molding machine, melting it into a mold in the injection molding machine to obtain a bottle embryo, the heating temperature of the injection molding machine is 240-300°C, and it is divided into five temperature zones from left to right, wherein the temperature of the first temperature zone is 240°C, the temperature of the second temperature zone is 260°C, the temperature of the third temperature zone is 280°C, the temperature of the fourth temperature zone is 300°C, and the temperature of the fifth temperature zone is 280°C; Step 2: preheat the preform at 180° C. for 5 min using a heating lamp, put it into a blow molding mold with 0.03 mm polytetrafluoroethylene and blow mold it at 140° C., and then cool it to room temperature at 3.2 MPa to obtain the plastic bottle.

[0049] In this embodiment, the blow mold includes a left module, a right module and a bottom module, and the polytetrafluoroethylene is located on the bottom module of the blow mold.

[0050] Example 2 The present embodiment provides a recycled polyethylene terephthalate material, wherein the recycled polyethylene terephthalate material is prepared by modifying waste polyethylene terephthalate with polyethylene terephthalate-1,4-cyclohexanedimethanol ester and an antioxidant in a molten state, and then melt-mixing with fresh polyethylene terephthalate; the light transmittance of the recycled polyethylene terephthalate material is 95%, the cantilever beam notched impact strength of the recycled polyethylene terephthalate material is 35.1 J / m, the tensile strength is 53 MPa, and the elongation at break is 21%. At 275°C and a load of 2.16 kg, the melt index of the recycled polyethylene terephthalate material is 22.2 g / min, and the heat resistance temperature of the recycled polyethylene terephthalate material is 88°C.

[0051] In this embodiment, the mass ratio of the waste polyethylene terephthalate to the polyethylene terephthalate-1,4-cyclohexanedimethanol ester is 1:2; The mass ratio of the waste polyethylene terephthalate to the fresh polyethylene terephthalate is 1:2; The tensile strength of the waste polyethylene terephthalate is 32 MPa, the elongation at break is 3%, and the melt index of the waste polyethylene terephthalate is 13.8 g / min at 275° C. and a load of 2.16 kg; The polyethylene terephthalate-1,4-cyclohexanedimethanol ester has an Izod notched impact strength of 7.9 J / m, an elongation at break of 120%, and a melt index of 15.3 g / min at 275° C. and a load of 2.16 kg; The fresh polyethylene terephthalate has an Izod notched impact strength of 68.6 J / m and an elongation at break of 3%. At 275°C and a load of 2.16 kg, the melt index of the fresh polyethylene terephthalate is 27.3 cm 3 / 10min; The antioxidant is a compound of an alcohol ester antioxidant and a phosphite antioxidant in a mass ratio of 2:1; The alcohol ester antioxidant is β-(3,5-di-tert-butyl, 4-hydroxyphenyl) propionate octadecyl alcohol ester (antioxidant 1076), and the phosphite antioxidant is bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite (antioxidant 626); The mass ratio of the waste polyethylene terephthalate, the polyethylene terephthalate-1,4-cyclohexanedimethanol ester and the antioxidant is 1:2:0.003.

[0052] This embodiment also provides a method for preparing the recycled polyethylene terephthalate material, comprising the following steps: Step 1, after mixing waste polyethylene terephthalate, polyethylene terephthalate-1,4-cyclohexanedimethanol ester and an antioxidant in a high-speed mixer at 300r / min for 10min, adding the mixture into a twin-screw extruder, wherein the processing temperature of the twin-screw extruder is 240-270°C, and the mixture is divided into 5 temperature zones, wherein the first temperature zone is 240°C, the second temperature zone is 260°C, the third temperature zone is 270°C, the fourth temperature zone is 270°C, and the fifth temperature zone is 250°C, and pelletizing is performed to obtain a mixed masterbatch; Step 2: After mixing the mixed masterbatch and fresh polyethylene terephthalate in a high-speed mixer at 300 r / min for 10 min, the mixture is added to a twin-screw extruder for melt blending, extruded and pelletized to obtain the recycled polyethylene terephthalate material. The processing temperature of the twin-screw extruder is 240-300°C, which is divided into five temperature zones, wherein the temperature of the first temperature zone is 240°C, the temperature of the second temperature zone is 260°C, the temperature of the third temperature zone is 280°C, the temperature of the fourth temperature zone is 300°C, and the temperature of the fifth temperature zone is 280°C.

[0053] This embodiment also provides a plastic bottle, which is made by blow molding the recycled polyethylene terephthalate material through a blow molding mold with a coating; the thickness of the plastic bottle is 0.8 mm; the light transmittance of the plastic bottle is 95%, the heat resistance temperature of the plastic bottle is 85° C., and the water vapor barrier property of the plastic bottle is 3.5 g·mm / mm 2 ·d·kPa, oxygen barrier property is 99cm 3 mm / m 2 ·d·MPa.

[0054] This embodiment also provides a method for preparing a plastic bottle, comprising the following steps: Step 1, adding the recycled polyethylene terephthalate material into an injection molding machine, melting it into a mold in the injection molding machine to obtain a bottle embryo, the heating temperature of the injection molding machine is 240-300°C, and it is divided into five temperature zones from left to right, wherein the temperature of the first temperature zone is 240°C, the temperature of the second temperature zone is 260°C, the temperature of the third temperature zone is 280°C, the temperature of the fourth temperature zone is 300°C, and the temperature of the fifth temperature zone is 280°C; Step 2: preheat the preform at 190° C. for 3 minutes using a heating lamp, put it into a blow molding mold with 0.05 mm polytetrafluoroethylene and blow mold it at 140° C., and then cool it to room temperature at 3.2 MPa to obtain the plastic bottle.

[0055] In this embodiment, the blow mold includes a left module, a right module and a bottom module, and the polytetrafluoroethylene is located on the bottom module of the blow mold.

[0056] Example 3 The present embodiment provides a recycled polyethylene terephthalate material, wherein the recycled polyethylene terephthalate material is prepared by modifying waste polyethylene terephthalate with polyethylene terephthalate-1,4-cyclohexanedimethanol ester and an antioxidant in a molten state, and then melt-mixing with fresh polyethylene terephthalate; the light transmittance of the recycled polyethylene terephthalate material is 90%, the cantilever beam notched impact strength of the recycled polyethylene terephthalate material is 34 J / m, the tensile strength is 56 MPa, and the elongation at break is 17%. At 275°C and a load of 2.16 kg, the melt index of the recycled polyethylene terephthalate material is 13 g / min, and the heat resistance temperature of the recycled polyethylene terephthalate material is 82°C.

[0057] In this embodiment, the mass ratio of the waste polyethylene terephthalate to the polyethylene terephthalate-1,4-cyclohexanedimethanol ester is 1:2; The mass ratio of the waste polyethylene terephthalate to the fresh polyethylene terephthalate is 1:1; The tensile strength of the waste polyethylene terephthalate is 32 MPa, the elongation at break is 1%, and the melt index of the waste polyethylene terephthalate is 13.8 g / min at 275° C. and a load of 2.16 kg; The polyethylene terephthalate-1,4-cyclohexanedimethanol ester has an Izod notched impact strength of 7.9 J / m, an elongation at break of 150%, and a melt index of 15.3 g / min at 275° C. and a load of 2.16 kg; The fresh polyethylene terephthalate has an Izod notched impact strength of 68.6 J / m and an elongation at break of 2%. At 275°C and a load of 2.16 kg, the melt index of the fresh polyethylene terephthalate is 27.3 cm 3 / 10min; The antioxidant is a compound of an alcohol ester antioxidant and a phosphite antioxidant in a mass ratio of 2:1; The alcohol ester antioxidant is 2,6-di-tert-butyl-p-cresol (antioxidant 264), and the phosphite antioxidant is bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite (antioxidant 626); The mass ratio of the waste polyethylene terephthalate, the polyethylene terephthalate-1,4-cyclohexanedimethanol ester and the antioxidant is 1:2:0.003.

[0058] This embodiment also provides a method for preparing the recycled polyethylene terephthalate material, comprising the following steps: Step 1, mixing waste polyethylene terephthalate, polyethylene terephthalate-1,4-cyclohexanedimethanol ester and an antioxidant in a high-speed mixer at 500r / min for 5min, adding the mixture into a twin-screw extruder, wherein the processing temperature of the twin-screw extruder is 240-270°C, and the mixture is divided into five temperature zones, wherein the first temperature zone is 240°C, the second temperature zone is 260°C, the third temperature zone is 270°C, the fourth temperature zone is 270°C, and the fifth temperature zone is 250°C, and pelletizing is performed to obtain a mixed masterbatch; Step 2: After mixing the mixed masterbatch and fresh polyethylene terephthalate in a high-speed mixer at 500 r / min for 5 minutes, adding the mixture into a twin-screw extruder for melt blending, extruding and pelletizing to obtain the recycled polyethylene terephthalate material. The processing temperature of the twin-screw extruder is 240-300°C, which is divided into five temperature zones, wherein the temperature of the first temperature zone is 240°C, the temperature of the second temperature zone is 260°C, the temperature of the third temperature zone is 280°C, the temperature of the fourth temperature zone is 300°C, and the temperature of the fifth temperature zone is 280°C.

[0059] This embodiment also provides a plastic bottle, which is made by blow molding the recycled polyethylene terephthalate material through a blow molding mold with a coating; the thickness of the plastic bottle is 1 mm; the light transmittance of the plastic bottle is 91%, the heat resistance temperature of the plastic bottle is 95° C., and the water vapor barrier property of the plastic bottle is 4.8 g·mm / mm 2 ·d·kPa, oxygen barrier property is 103cm 3 mm / m 2 ·d·MPa.

[0060] This embodiment also provides a method for preparing a plastic bottle, comprising the following steps: Step 1, adding the recycled polyethylene terephthalate material into an injection molding machine, melting it into a mold in the injection molding machine to obtain a bottle embryo, the heating temperature of the injection molding machine is 240-300°C, and it is divided into five temperature zones from left to right, wherein the temperature of the first temperature zone is 240°C, the temperature of the second temperature zone is 260°C, the temperature of the third temperature zone is 280°C, the temperature of the fourth temperature zone is 300°C, and the temperature of the fifth temperature zone is 280°C; Step 2: preheat the preform at 190° C. for 3 minutes using a heating lamp, put it into a blow molding mold with 0.05 mm polytetrafluoroethylene and blow mold it at 140° C., and then cool it to room temperature at 3.2 MPa to obtain the plastic bottle.

[0061] In this embodiment, the blow mold includes a left module, a right module and a bottom module, and the polytetrafluoroethylene is located on the bottom module of the blow mold.

[0062] Example 4 The present embodiment provides a recycled polyethylene terephthalate material, wherein the recycled polyethylene terephthalate material is prepared by modifying waste polyethylene terephthalate with polyethylene terephthalate-1,4-cyclohexanedimethanol ester and an antioxidant in a molten state, and then melt-mixing with fresh polyethylene terephthalate; the light transmittance of the recycled polyethylene terephthalate material is 92%, the cantilever beam notched impact strength of the recycled polyethylene terephthalate material is 37.5 J / m, the tensile strength is 54 MPa, and the elongation at break is 17%. At 275°C and a load of 2.16 kg, the melt index of the recycled polyethylene terephthalate material is 12.9 g / min, and the heat resistance temperature of the recycled polyethylene terephthalate material is 89°C.

[0063] In this embodiment, the mass ratio of the waste polyethylene terephthalate to the polyethylene terephthalate-1,4-cyclohexanedimethanol ester is 1:1.2; The mass ratio of the waste polyethylene terephthalate to the fresh polyethylene terephthalate is 1:2; The tensile strength of the waste polyethylene terephthalate is 32 MPa, the elongation at break is 3%, and the melt index of the waste polyethylene terephthalate is 13.8 g / min at 275° C. and a load of 2.16 kg; The polyethylene terephthalate-1,4-cyclohexanedimethanol ester has an Izod notched impact strength of 7.9 J / m, an elongation at break of 130%, and a melt index of 15.3 g / min at 275° C. and a load of 2.16 kg; The fresh polyethylene terephthalate has an Izod notched impact strength of 68.6 J / m and an elongation at break of 3%. At 275°C and a load of 2.16 kg, the melt index of the fresh polyethylene terephthalate is 27.3 cm 3 / 10min; The antioxidant is a compound of an alcohol ester antioxidant and a phosphite antioxidant in a mass ratio of 2:1; The alcohol ester antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (antioxidant 1010), and the phosphite antioxidant is tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168); The mass ratio of the waste polyethylene terephthalate, the polyethylene terephthalate-1,4-cyclohexanedimethanol ester and the antioxidant is 1:2:0.003.

[0064] This embodiment also provides a method for preparing the recycled polyethylene terephthalate material, comprising the following steps: Step 1, mixing waste polyethylene terephthalate, polyethylene terephthalate-1,4-cyclohexanedimethanol ester and an antioxidant in a high-speed mixer at 500r / min for 5min, adding the mixture into a twin-screw extruder, wherein the processing temperature of the twin-screw extruder is 240-270°C, and the mixture is divided into five temperature zones, wherein the first temperature zone is 240°C, the second temperature zone is 260°C, the third temperature zone is 270°C, the fourth temperature zone is 270°C, and the fifth temperature zone is 250°C, and pelletizing is performed to obtain a mixed masterbatch; Step 2: After mixing the mixed masterbatch and fresh polyethylene terephthalate in a high-speed mixer at 500 r / min for 5 minutes, adding the mixture into a twin-screw extruder for melt blending, extruding and pelletizing to obtain the recycled polyethylene terephthalate material. The processing temperature of the twin-screw extruder is 240-300°C, which is divided into five temperature zones, wherein the temperature of the first temperature zone is 240°C, the temperature of the second temperature zone is 260°C, the temperature of the third temperature zone is 280°C, the temperature of the fourth temperature zone is 300°C, and the temperature of the fifth temperature zone is 280°C.

[0065] This embodiment also provides a plastic bottle, which is made by blow molding the recycled polyethylene terephthalate material through a blow molding mold with a coating; the thickness of the plastic bottle is 0.8 mm; the light transmittance of the plastic bottle is 93%, the heat resistance temperature of the plastic bottle is 93°C, and the water vapor barrier property of the plastic bottle is 4.2 g·mm / mm 2 ·d·kPa, oxygen barrier property is 71cm 3 mm / m 2 ·d·MPa.

[0066] This embodiment also provides a method for preparing a plastic bottle, comprising the following steps: Step 1, adding the recycled polyethylene terephthalate material into an injection molding machine, melting it into a mold in the injection molding machine to obtain a bottle embryo, the heating temperature of the injection molding machine is 240-300°C, and it is divided into five temperature zones from left to right, wherein the temperature of the first temperature zone is 240°C, the temperature of the second temperature zone is 260°C, the temperature of the third temperature zone is 280°C, the temperature of the fourth temperature zone is 300°C, and the temperature of the fifth temperature zone is 280°C; Step 2: preheat the preform at 180° C. for 5 min using a heating lamp, put it into a blow molding mold with 0.03 mm polytetrafluoroethylene and blow mold it at 140° C., and then cool it to room temperature at 3.2 MPa to obtain the plastic bottle.

[0067] In this embodiment, the blow mold includes a left module, a right module and a bottom module, and the polytetrafluoroethylene is located on the bottom module of the blow mold.

[0068] Comparative Example 1 This comparative example provides a recycled polyethylene terephthalate material, which is prepared by melt mixing of waste polyethylene terephthalate and fresh polyethylene terephthalate; the light transmittance of the recycled polyethylene terephthalate material is 64%, the cantilever beam notched impact strength of the recycled polyethylene terephthalate material is 20.5 J / m, the tensile strength is 39 MPa, and the elongation at break is 3%. At 275°C and a load of 2.16 kg, the melt index of the recycled polyethylene terephthalate material is 21.1 g / min, and the heat resistance temperature of the recycled polyethylene terephthalate material is 63°C.

[0069] In this comparative example, the mass ratio of the waste polyethylene terephthalate to the fresh polyethylene terephthalate is 1:1; The tensile strength of the waste polyethylene terephthalate is 32 MPa, the elongation at break is 3%, and the melt index of the waste polyethylene terephthalate is 13.8 g / min at 275° C. and a load of 2.16 kg; The fresh polyethylene terephthalate has an Izod notched impact strength of 68.6 J / m and an elongation at break of 3%. At 275°C and a load of 2.16 kg, the melt index of the fresh polyethylene terephthalate is 27.3 cm 3 / 10min.

[0070] This comparative example also provides a method for preparing the recycled polyethylene terephthalate material, comprising the following steps: Waste polyethylene terephthalate and fresh polyethylene terephthalate are mixed in a high-speed mixer at 500 r / min for 5 minutes, and then added into a twin-screw extruder for melt blending, extrusion and pelletization to obtain the recycled polyethylene terephthalate material.

[0071] In this comparative example, the processing temperature of the twin-screw extruder is 240-300°C, which is divided into five temperature zones, wherein the temperature of the first temperature zone is 240°C, the temperature of the second temperature zone is 260°C, the temperature of the third temperature zone is 280°C, the temperature of the fourth temperature zone is 300°C, and the temperature of the fifth temperature zone is 280°C.

[0072] The comparative example also provides a plastic bottle, which is prepared by blow molding the recycled polyethylene terephthalate material through a blow molding mold with a coating; the thickness of the plastic bottle is 0.8 mm; the light transmittance of the plastic bottle is 62%, the heat resistance temperature of the plastic bottle is 61°C, and the water vapor barrier property of the plastic bottle is 23.7 g·mm / mm 2 ·d·kPa, oxygen barrier property is 242cm 3 mm / m 2 ·d·MPa.

[0073] This comparative example also provides a method for preparing a plastic bottle, comprising the following steps: Step 1, adding the recycled polyethylene terephthalate material into an injection molding machine, melting it into a mold in the injection molding machine to obtain a bottle embryo, the heating temperature of the injection molding machine is 240-300°C, and it is divided into five temperature zones from left to right, wherein the temperature of the first temperature zone is 240°C, the temperature of the second temperature zone is 260°C, the temperature of the third temperature zone is 280°C, the temperature of the fourth temperature zone is 300°C, and the temperature of the fifth temperature zone is 280°C; Step 2: preheat the preform at 180° C. for 5 min using a heating lamp, put it into a blow molding mold with 0.03 mm polytetrafluoroethylene and blow mold it at 140° C., and then cool it to room temperature at 3.2 MPa to obtain the plastic bottle.

[0074] In this comparative example, the blow mold includes a left module, a right module and a bottom module, and the polytetrafluoroethylene is located on the bottom module of the blow mold.

[0075] Comparative Example 2 The comparative example provides a recycled polyethylene terephthalate material, wherein the recycled polyethylene terephthalate material is prepared by modifying waste polyethylene terephthalate with polyethylene terephthalate-1,4-cyclohexanedimethanol ester and an antioxidant in a molten state, and then melt-mixing with fresh polyethylene terephthalate; the light transmittance of the recycled polyethylene terephthalate material is 88%, the cantilever beam notched impact strength of the recycled polyethylene terephthalate material is 28.9 J / m, the tensile strength is 44 MPa, the elongation at break is 15%, and the melt index of the recycled polyethylene terephthalate material is 15.9 g / min at 275°C and a load of 2.16 kg, and the heat resistance temperature of the recycled polyethylene terephthalate material is 81°C.

[0076] In this comparative example, the mass ratio of the waste polyethylene terephthalate to the polyethylene terephthalate-1,4-cyclohexanedimethanol ester is 1:1.2; The mass ratio of the waste polyethylene terephthalate to the fresh polyethylene terephthalate is 1:2; The tensile strength of the waste polyethylene terephthalate is 32 MPa, the elongation at break is 3%, and the melt index of the waste polyethylene terephthalate is 13.8 g / min at 275° C. and a load of 2.16 kg; The polyethylene terephthalate-1,4-cyclohexanedimethanol ester has an Izod notched impact strength of 7.9 J / m, an elongation at break of 130%, and a melt index of 15.3 g / min at 275° C. and a load of 2.16 kg; The fresh polyethylene terephthalate has an Izod notched impact strength of 68.6 J / m and an elongation at break of 3%. At 275°C and a load of 2.16 kg, the melt index of the fresh polyethylene terephthalate is 27.3 cm 3 / 10min; The antioxidant is a compound of an alcohol ester antioxidant and a phosphite antioxidant in a mass ratio of 2:1; The alcohol ester antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (antioxidant 1010), and the phosphite antioxidant is tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168); The mass ratio of the waste polyethylene terephthalate, the polyethylene terephthalate-1,4-cyclohexanedimethanol ester and the antioxidant is 1:2:0.003.

[0077] This comparative example also provides a method for preparing the recycled polyethylene terephthalate material, comprising the following steps: Step 1, mixing waste polyethylene terephthalate, polyethylene terephthalate-1,4-cyclohexanedimethanol ester and an antioxidant in a high-speed mixer at 500r / min for 5min, adding the mixture into a twin-screw extruder, wherein the processing temperature of the twin-screw extruder is 200-240°C, and the mixture is divided into five temperature zones, wherein the first temperature zone is 200°C, the second temperature zone is 220°C, the third temperature zone is 240°C, the fourth temperature zone is 240°C, and the fifth temperature zone is 230°C, and pelletizing is performed to obtain a mixed masterbatch; Step 2: After mixing the mixed masterbatch and fresh polyethylene terephthalate in a high-speed mixer at 500 r / min for 5 minutes, adding the mixture into a twin-screw extruder for melt blending, extruding and pelletizing to obtain the recycled polyethylene terephthalate material. The processing temperature of the twin-screw extruder is 240-300°C, which is divided into five temperature zones, wherein the temperature of the first temperature zone is 240°C, the temperature of the second temperature zone is 260°C, the temperature of the third temperature zone is 280°C, the temperature of the fourth temperature zone is 300°C, and the temperature of the fifth temperature zone is 280°C.

[0078] The comparative example also provides a plastic bottle, which is prepared by blow molding the recycled polyethylene terephthalate material through a blow molding mold with a coating; the thickness of the plastic bottle is 0.8 mm; the light transmittance of the plastic bottle is 87%, the heat resistance temperature of the plastic bottle is 82°C, and the water vapor barrier property of the plastic bottle is 5.1 g·mm / mm 2 ·d·kPa, oxygen barrier property is 87cm 3 mm / m 2 ·d·MPa.

[0079] This comparative example also provides a method for preparing a plastic bottle, comprising the following steps: Step 1, adding the recycled polyethylene terephthalate material into an injection molding machine, melting it into a mold in the injection molding machine to obtain a bottle embryo, the heating temperature of the injection molding machine is 240-300°C, and it is divided into five temperature zones from left to right, wherein the temperature of the first temperature zone is 240°C, the temperature of the second temperature zone is 260°C, the temperature of the third temperature zone is 280°C, the temperature of the fourth temperature zone is 300°C, and the temperature of the fifth temperature zone is 280°C; Step 2: preheat the preform at 180° C. for 5 min using a heating lamp, put it into a blow molding mold with 0.03 mm polytetrafluoroethylene and blow mold it at 140° C., and then cool it to room temperature at 3.2 MPa to obtain the plastic bottle.

[0080] In this comparative example, the blow mold includes a left module, a right module and a bottom module, and the polytetrafluoroethylene is located on the bottom module of the blow mold.

[0081] Comparative Example 3 The comparative example provides a recycled polyethylene terephthalate material, which is prepared by modifying waste polyethylene terephthalate with polyethylene terephthalate-1,4-cyclohexanedimethanol ester and an antioxidant in a molten state, and then melt-mixing with fresh polyethylene terephthalate; the light transmittance of the recycled polyethylene terephthalate material is 89%, the cantilever beam notched impact strength of the recycled polyethylene terephthalate material is 37.2 J / m, the tensile strength is 55 MPa, and the elongation at break is 11%. At 275°C and a load of 2.16 kg, the melt index of the recycled polyethylene terephthalate material is 20.8 g / min, and the heat resistance temperature of the recycled polyethylene terephthalate material is 83°C.

[0082] In this comparative example, the mass ratio of the waste polyethylene terephthalate to the polyethylene terephthalate-1,4-cyclohexanedimethanol ester is 1:1.2; The mass ratio of the waste polyethylene terephthalate to the fresh polyethylene terephthalate is 1:2; The tensile strength of the waste polyethylene terephthalate is 32 MPa, the elongation at break is 3%, and the melt index of the waste polyethylene terephthalate is 13.8 g / min at 275° C. and a load of 2.16 kg; The polyethylene terephthalate-1,4-cyclohexanedimethanol ester has an Izod notched impact strength of 7.9 J / m, an elongation at break of 130%, and a melt index of 15.3 g / min at 275° C. and a load of 2.16 kg; The fresh polyethylene terephthalate has an Izod notched impact strength of 68.6 J / m and an elongation at break of 3%. At 275°C and a load of 2.16 kg, the melt index of the fresh polyethylene terephthalate is 27.3 cm 3 / 10min; The antioxidant is a compound of an alcohol ester antioxidant and a phosphite antioxidant in a mass ratio of 2:1; The alcohol ester antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (antioxidant 1010), and the phosphite antioxidant is tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168); The mass ratio of the waste polyethylene terephthalate, the polyethylene terephthalate-1,4-cyclohexanedimethanol ester and the antioxidant is 1:2:0.003.

[0083] This comparative example also provides a method for preparing the recycled polyethylene terephthalate material, comprising the following steps: Step 1, mixing waste polyethylene terephthalate, polyethylene terephthalate-1,4-cyclohexanedimethanol ester and an antioxidant in a high-speed mixer at 500r / min for 5min, adding the mixture into a twin-screw extruder, wherein the processing temperature of the twin-screw extruder is 240-270°C, and the mixture is divided into five temperature zones, wherein the first temperature zone is 240°C, the second temperature zone is 260°C, the third temperature zone is 270°C, the fourth temperature zone is 270°C, and the fifth temperature zone is 250°C, and pelletizing is performed to obtain a mixed masterbatch; Step 2: After mixing the mixed masterbatch and fresh polyethylene terephthalate in a high-speed mixer at 500 r / min for 5 minutes, adding the mixture into a twin-screw extruder for melt blending, extruding and pelletizing to obtain the recycled polyethylene terephthalate material. The processing temperature of the twin-screw extruder is 240-300°C, which is divided into five temperature zones, wherein the temperature of the first temperature zone is 240°C, the temperature of the second temperature zone is 260°C, the temperature of the third temperature zone is 280°C, the temperature of the fourth temperature zone is 300°C, and the temperature of the fifth temperature zone is 280°C.

[0084] The comparative example also provides a plastic bottle, which is prepared by blow molding the recycled polyethylene terephthalate material through a blow molding mold with a coating; the thickness of the plastic bottle is 0.8 mm; the light transmittance of the plastic bottle is 90%, the heat resistance temperature of the plastic bottle is 83°C, and the water vapor barrier property of the plastic bottle is 4.6 g·mm / mm 2 ·d·kPa, oxygen barrier property is 77cm 3 mm / m 2 ·d·MPa.

[0085] This comparative example also provides a method for preparing a plastic bottle, comprising the following steps: Step 1, adding the recycled polyethylene terephthalate material into an injection molding machine, melting it into a mold in the injection molding machine to obtain a bottle embryo, the heating temperature of the injection molding machine is 240-300°C, and it is divided into five temperature zones from left to right, wherein the temperature of the first temperature zone is 240°C, the temperature of the second temperature zone is 260°C, the temperature of the third temperature zone is 280°C, the temperature of the fourth temperature zone is 300°C, and the temperature of the fifth temperature zone is 280°C; Step 2: preheat the preform at 180° C. for 5 minutes using a heating lamp, put it into a blow molding mold with 0.03 mm polytetrafluoroethylene and blow mold it at 100° C., and then cool it to room temperature at 3.2 MPa to obtain the plastic bottle.

[0086] In this comparative example, the blow mold includes a left module, a right module and a bottom module, and the polytetrafluoroethylene is located on the bottom module of the blow mold.

[0087] Table 1 shows the performance test of the recycled polyethylene terephthalate materials described in Examples 1-4 and Comparative Examples 1-3.

[0088] Table 2 is the performance test of the plastic bottles described in Examples 1-4 and Comparative Examples 1-3

[0089] As shown in Table 1, the performance test of the recycled polyethylene terephthalate materials described in Examples 1-4 and Comparative Examples 1-3, wherein Examples 1-4 are prepared by blending waste polyethylene terephthalate with fresh polyethylene terephthalate after being modified with polyethylene terephthalate-1,4-cyclohexanedimethanol ester and an antioxidant, and have high light transmittance, good mechanical properties, moderate melt index, and high heat resistance temperature, while in Comparative Example 1, waste polyethylene terephthalate After the ethylene glycol ester is not modified and blended with fresh polyethylene terephthalate, the light transmittance, mechanical properties and heat resistance temperature of the prepared recycled polyethylene terephthalate material are extremely poor due to the poor original performance of the waste polyethylene terephthalate. The temperature of the modification of the waste polyethylene terephthalate in Comparative Example 2 is low, the dispersibility during mixing is poor, and the performance is slightly worse than that of the recycled polyethylene terephthalate material in Examples 1-4.

[0090] Table 2 shows the performance tests of the plastic bottles described in Examples 1-4 and Comparative Examples 1-3. The plastic bottles in Examples 1-4 have good barrier properties, high heat resistance, and high light transmittance. In Comparative Example 3, the processing temperature of the blow mold was changed. Due to the low processing temperature, the heat resistance of the plastic bottles is poor.

[0091] The test standard for light transmittance described in the present invention is GB / T 2410-2008. The test conditions for water vapor barrier properties are as follows: the initial weight of the plastic bottle is W0, purified water is added to the plastic bottle to 3 / 4 of the full capacity after sealing, the lid is tightened with a torque of 30N·cm-90N·cm, the outer surface is wiped clean with silk cloth, and the weight of the plastic bottle at this time is W1, and then the plastic bottle is placed in a constant temperature and humidity chamber at a temperature of 40℃±2℃ and a relative humidity of 25%±5% for 14 days, taken out, and placed at room temperature for 45 minutes before weighing again, and the weight of the plastic bottle at this time is W2, and the water vapor barrier property is expressed by (W1-W2) / (W1-W0)*100%; The test standard for oxygen barrier properties is "ASTM F1307-02".

[0092] Based on the above, it can be seen that the recycled polyethylene terephthalate material of the present invention has a wide range of applications, low cost and a very high market prospect.

[0093] The above description is only a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any modification or equivalent change made based on the technical essence of the present invention still falls within the scope of protection required by the present invention.

Claims

1. A recycled polyethylene terephthalate material, characterized in that: The recycled polyethylene terephthalate material is prepared by modifying waste polyethylene terephthalate with polyethylene terephthalate-1,4-cyclohexanedimethanol ester and an antioxidant in a molten state, and then melt-mixing with fresh polyethylene terephthalate; the light transmittance of the recycled polyethylene terephthalate material is 90-95%, the cantilever beam notched impact strength of the recycled polyethylene terephthalate material is 33-37.5 J / m, the tensile strength is 47-56 MPa, the elongation at break is 17-21%, and the melt index of the recycled polyethylene terephthalate material is 12-22 g / min at 275° C. and a load of 2.16 kg, and the heat resistance temperature of the recycled polyethylene terephthalate material is 82-89° C.

2. The recycled polyethylene terephthalate material according to claim 1, characterized in that: The mass ratio of the waste polyethylene terephthalate to the polyethylene terephthalate-1,4-cyclohexanedimethanol ester is (1:1.2)-(1:2).

3. The recycled polyethylene terephthalate material according to claim 1, characterized in that: The mass ratio of the waste polyethylene terephthalate to the fresh polyethylene terephthalate is (1:1)-(1:2).

4. A method for preparing the recycled polyethylene terephthalate material according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1, mixing waste polyethylene terephthalate, polyethylene terephthalate-1,4-cyclohexanedimethanol and an antioxidant in a high-speed mixer, adding the mixture into a twin-screw extruder, heating and mixing, and pelletizing to obtain a mixed masterbatch; Step 2: After mixing the mixed masterbatch and fresh polyethylene terephthalate in a high-speed mixer, adding the mixture into a twin-screw extruder for melt blending, extruding and pelletizing to obtain the recycled polyethylene terephthalate material.

5. The preparation method according to claim 4, characterized in that: The temperature of the heating and mixing in step 1 is 240-270°C, which is divided into 5 temperature zones, wherein the first temperature zone is 240°C, the second temperature zone is 260°C, the third temperature zone is 270°C, the fourth temperature zone is 270°C, and the fifth temperature zone is 250°C.

6. A plastic bottle, characterized in that: The plastic bottle is made by blow molding the recycled polyethylene terephthalate material according to any one of claims 1 to 3 through a blow molding mold with a coating; the thickness of the plastic bottle is 0.5-1 mm; the light transmittance of the plastic bottle is 90-95%, the heat resistance temperature of the plastic bottle is 82-89° C., and the water vapor barrier property of the plastic bottle is 3.5-4.8 g·mm / mm 2 ·d·kPa, oxygen barrier property is 71-103cm 3 mm / m 2 ·d·MPa.

7. A method for preparing the plastic bottle according to claim 6, characterized in that: The following steps are involved: Step 1, adding the recycled polyethylene terephthalate material into an injection molding machine, melting it into a mold in the injection molding machine, and obtaining a bottle embryo; Step 2: preheat the bottle embryo with a heating lamp, put it into a blow molding mold with a coating, and blow mold it, and cool it to obtain the plastic bottle.

8. The preparation method according to claim 7, characterized in that: The coating in step 2 is polytetrafluoroethylene, and the thickness of the coating is 0.03-0.05 mm.

9. The preparation method according to claim 7, characterized in that: The heating temperature of the blow molding mold in step 2 is 140°C.

10. The preparation method according to claim 7, characterized in that: The cooling method in step 2 is to introduce medium-pressure compressed air into the bottle embryo, and the pressure of the medium-pressure compressed air is 3.2 MPa.

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