PCR-pet composition, and preparation method therefor and use thereof

Abstract

Disclosed in the present invention are a PCR-PET composition, and a preparation method therefor and a use thereof. The PCR-PET composition comprises the following components in parts by weight: 78-88 parts of a PCR-PET resin; 12-20 parts of a toughening agent; 0.2-0.8 parts of a nucleating agent; and 0-0.5 parts of an antioxidant. According to the present invention, a PCR-PET resin having a specific yellow flake content is selected, a certain amount of a toughening agent (E-MA-GMA or E-BA-GMA) is added, and the GMA content of the toughening agent is optimized, such that a high-toughness PCR-PET composition having an impact strength greater than 19 kJ / m2 and allowing for production of injection molded parts having good appearance is prepared, thereby satisfying the use requirements of products having high toughness and realizing recycling of PCR-PET.

Description

A PCR-PET composition and its preparation method and application Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a PCR-PET composition, a preparation method and an application thereof. Background Art

[0002] Polyethylene terephthalate (PET) is a semi-crystalline thermoplastic polyester. In addition to being used for synthetic fibers, PET's applications have expanded to various types of containers, packaging materials, films, films, engineering plastics and many other fields. With the substantial increase in the use of plastics, recycling and reusing waste plastics as resources has become a top priority for environmental protection in countries around the world. PCR-PET is post-consumer recycled PET, and its main source is post-consumer recycled PET bottles, such as mineral water bottles, beverage bottles, oil bottles, cosmetic bottles, medicine bottles, etc. Due to the recycling process, the mechanical properties of PCR-PET are greatly reduced, especially the toughness is poor (the notched impact strength is generally only 2-4kJ / m 2 ), which greatly limits the practical application of PCR-PET.

[0003] Chinese patent application CN115895208A discloses a PET composite material containing a PCR-PET film material. The PCR-PET film material and a nucleating agent are used to improve the crystallization properties of PET, thereby enhancing the mechanical properties and heat resistance. However, the toughness of the material is not significantly improved. Summary of the Invention

[0004] In order to overcome the deficiencies of the above-mentioned prior art, the object of the present invention is to provide a high-toughness PCR-PET composition having high impact strength and good appearance of injection-molded parts.

[0005] Another object of the present invention is to provide a method for preparing the above-mentioned PCR-PET composition.

[0006] The present invention is achieved through the following technical solutions:

[0007] A PCR-PET composition, comprising the following components in parts by weight:

[0008] 78-88 parts of PCR-PET resin;

[0009] 12-20 parts of toughening agent;

[0010] Nucleating agent 0.2-0.8 parts;

[0011] Antioxidant 0-0.5 parts.

[0012] The weight parts of the PCR-PET resin can be 78 parts, 80 parts, 82 parts, 84 parts, 86 parts or 88 parts, as well as specific values ​​between the above points.

[0013] The weight percentage of the toughening agent can be 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts or 18 parts, as well as specific values ​​between the above points.

[0014] The weight percentage of the nucleating agent can be 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts or 0.8 parts, as well as specific values ​​between the above points.

[0015] The present invention uses "yellow flake content" to characterize the degree of crosslinking after aging of the PCR-PET resin. The yellow flakes herein refer to PCR-PET fragments that appear yellow, darken, become carbonized and sticky, or have grease deposited on the surface after baking at 220°C for 50 minutes.

[0016] The specific test method for the yellow flake content of the PCR-PET resin described in the present invention is as follows: 1 kg of PCR-PET fragment sample (sample specifications: irregularly shaped fragments, thickness 0.2-0.8 mm, average diameter 10-14 mm, the diameter being the maximum diameter of the irregularly shaped fragment sample) is taken, placed in a 220° C. oven, and baked for 50 minutes. Immediately after taking out, the residual fragments in the PCR-PET are sorted, and yellowed flakes, aged flakes, sticky flakes, and oily flakes are removed (the yellowed flakes are specifically fragments that turn yellow after baking and have no grease on the surface; the aged flakes are specifically fragments with a darker color after baking; the sticky flakes are fragments that are carbonized and sticky on the surface after baking; the oily flakes are fragments that turn yellow after baking and have grease precipitated on the surface; refer to the corresponding yellowed flake / aged flake / sticky flake / oil flake schematic diagram in Figure 1), weighed, and the ratio of yellowed flakes / aged flakes / sticky flakes / oily flakes to the total PCR-PET fragment sample is calculated, which is the yellow flake content of the PCR-PET resin.

[0017] Preferably, the present invention selects a PCR-PET resin with a yellow flake content of ≤2000 ppm, more preferably a PCR-PET resin with a yellow flake content of 100-1200 ppm. In the material system of the present invention, if a PCR-PET resin with too high a yellow flake content is used, the resin system will undergo excessive crosslinking upon aging, failing to produce a highly tough PCR-PET composition. This will also affect the appearance of the injection-molded parts, resulting in wrinkles, shine, or yellowing.

[0018] The present invention further prefers PCR-PET resins having an intrinsic viscosity of 0.73 to 0.90 dL / g. The intrinsic viscosity is tested in accordance with GB / T 14190-2017.

[0019] Preferably, the PCR-PET of the present invention is derived from post-consumer recycled PET bottles, including mineral water bottles, beverage bottles, oil bottles, cosmetic bottles or pharmaceutical bottles.

[0020] The toughening agent of the present invention is selected from any one or more of ethylene-methyl acrylate-glycidyl methacrylate block copolymer (E-MA-GMA) or ethylene-butyl acrylate-glycidyl methacrylate block copolymer (E-BA-GMA). Preferably, the GMA content in the toughening agent is 5-10%, more preferably 7-9%.

[0021] More preferably, the toughening agent has a melt index of 3-15 g / 10 min, more preferably 6-12 g / 10 min, at 190° C. and 2.16 kg. The melt index is tested according to ISO 1133-2011.

[0022] Preferably, the nucleating agent is selected from one of sodium montmorillonite soap, calcium montmorillonite soap or amino acid calcium soap.

[0023] Preferably, the antioxidant is selected from at least one of hindered phenol antioxidants, phosphite antioxidants, and thioether antioxidants. Further, the hindered phenol antioxidant can be selected from pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0024] The present invention also provides a method for preparing the above-mentioned PCR-PET composition, comprising the following steps: adding the components into a mixer according to the ratio and mixing them evenly to obtain a premix; melt-extruding the premix at 190-270° C. through a twin-screw extruder, cooling, and granulating to prepare the PCR-PET composition.

[0025] Preferably, the PCR-PET resin is dried in advance to a moisture content of less than 0.1% and then blended with other components.

[0026] Preferably, the temperatures of the barrels of the twin-screw extruder from the feeding port to the die are: 250-270°C, 240-260°C, 230-250°C, 190-210°C, 190-210°C, 190-210°C, 190-210°C, 200-220°C, 220-240°C, the screw speed is 300-500 rpm, the feed rate is 200-400kg / h, and the vacuum degree is (-0.1)-0Mpa.

[0027] The present invention also provides the application of the above-mentioned PCR-PET composition in the field of household appliances, which is specifically suitable for products with high requirements for product toughness and excellent appearance, such as appliance housings.

[0028] The present invention has the following beneficial effects:

[0029] The present invention selects PCR-PET resin with a specific yellow flake content, adds a certain amount of toughening agent (E-MA-GMA or E-BA-GMA), and optimizes the GMA content of the toughening agent to prepare a composite material with an impact strength of >19kJ / m 2 The high-toughness PCR-PET composition with good appearance of injection-molded parts can meet the use requirements of products with high toughness and good appearance, and realize the recycling of PCR-PET. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic diagram of yellowing flakes / aging flakes / sticky flakes / oil flakes when testing the yellow flake content of PCR-PET resin. DETAILED DESCRIPTION

[0031] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several variations and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0032] The raw materials used in the examples and comparative examples of the present invention are described below, but are not limited to these materials:

[0033] PCR-PET resin 1: intrinsic viscosity 0.73-0.8 dL / g, yellow flake content 400 ppm, Suzhou Jiulong, SRPET-PGNC0123(LSK) 3A;

[0034] PCR-PET resin 2: intrinsic viscosity 0.73 dL / g, yellow flake content 2000 ppm, Jiulongtai Co., Ltd. & Xinhuatai Co., Ltd., JLT ZWT B2B white;

[0035] PCR-PET resin 3: intrinsic viscosity 0.73-0.8 dL / g, yellow flake content 1200 ppm, Suzhou Jiulong, SRPET-PGNC0123(LSK) A;

[0036] PCR-PET resin 4: intrinsic viscosity 0.73 dL / g, yellow flake content 4500 ppm, Jiulongtai Co., Ltd. & Xinhuatai Co., Ltd., JLT ZWT SHEET white;

[0037] Toughener 1: E-MA-GMA, GMA content 8%, melt index 6 g / 10 min at 190°C / 2.16 kg, Arkema, LOTADER AX8900;

[0038] Toughener 2: E-BA-GMA, GMA content 8%, melt index 9 g / 10 min at 190°C / 2.16 kg, Arkema, LOTADER AX8700;

[0039] Toughener 3: E-BA-GMA, GMA content 5%, melt index 12 g / 10 min at 190°C / 2.16 kg, DuPont, ELVALOY RESINS PTW;

[0040] Toughener 4: E-MA-GMA, GMA content 3%, melt index 7 g / 10 min at 190°C / 2.16 kg, Arkema, LOTADER AX8930;

[0041] Toughener 5: EMA, GMA content is 0%, melt index is 0.5g / 10min at 190℃ / 2.16kg, DuPont, ELVALOY AC RESIN 1125;

[0042] Nucleating agent: sodium montmorillonite soap, Guangzhou Fengtian Chemical Co., Ltd., LICOMONT NAV101 PWD;

[0043] Antioxidant: Pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, SONOX 1010, Linyi Sanfeng Chemical Co., Ltd., Shandong Province.

[0044] Preparation methods of the PCR-PET compositions of the Examples and Comparative Examples:

[0045] First, the PCR-PET resin is dried in advance to a moisture content of less than 0.1%; according to the ratio, the PCR-PET resin is added to a high-speed mixer together with other components and mixed for 2-5 minutes to obtain a premix, and the premix is ​​melt-extruded, cooled, and granulated through a twin-screw extruder to prepare a PCR-PET composition; wherein, the temperatures of the barrels of the twin-screw extruder from the feed port to the die are: 250-270°C, 240-260°C, 230-250°C, 190-210°C, 190-210°C, 190-210°C, 190-210°C, 190-210°C, 200-220°C, 220-240°C, the screw speed is 300-500 rpm, the feed rate is 200-400 kg / h, and the vacuum degree is (-0.1)-0 MPa.

[0046] Related performance test methods:

[0047] (1) Impact strength: Tested according to ISO 180-2019, pendulum energy 5.5 J;

[0048] (2) Appearance evaluation: The appearance of the stretched spline is judged as follows:

[0049] Level 1: Excellent appearance: The surface of the spline is flat and smooth, without yellowing or wrinkles;

[0050] Level 2: Good appearance: The surface of the spline is smooth, slightly rough;

[0051] Level 3: Poor appearance: The surface of the spline is wrinkled or shiny or yellow.

[0052] Table 1: Distribution ratios of each group in Examples 1-7 (by weight) and related performance test results

[0053] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 PCR-PET resin 184.584.584.57884.5PCR-PET resin 284.5PCR-PET resin 388Toughener 11515122015Toughener 215Toughener 315Nucleating agent 0.30.30.30.30.30.30.30.3Antioxidant 0.20.20.20.20.20.2 / Notched impact strength kJ / m 2 36.222.436.520.319.848.235.8Appearance Level 1 Level 2 Level 1 Level 1 Level 1 Level 1 Level 1

[0054] Table 2: Distribution ratio of each group in comparative examples 1-5 (by weight) and related performance test results

[0055] Comparative Example 1Comparative Example 2Comparative Example 3Comparative Example 4Comparative Example 5PCR-PET resin 184.584.584.584.5PCR-PET resin 484.5Toughener 115530Toughener 415Toughener 515Nucleating agent 0.30.30.30.30.3Antioxidant 0.20.20.20.20.2Notched impact strength kJ / m 2 8.911.84.256.87.8 Appearance Level 3 Level 1 Level 1 Level 3 Level 2

[0056] From the above results, it can be seen that the present invention selects PCR-PET resin with a specific yellow flake content, adds a certain amount of toughening agent (E-MA-GMA or E-BA-GMA), and optimizes the GMA content of the toughening agent to prepare an impact strength of >19kJ / m 2 , and a high-toughness PCR-PET composition with good appearance of injection-molded parts.

[0057] Comparative Example 1 uses PCR-PET resin with too high a content of yellow flakes, resulting in poor toughness of the material and poor appearance of the injection molded part.

[0058] In Comparative Example 2, a toughening agent with too low a GMA content was used, and the required toughness could not be achieved.

[0059] In Comparative Example 3, the amount of toughening agent added was too small, and the toughness of the material was poor.

[0060] In Comparative Example 4, too much toughening agent was added. Although the toughness was high, the excessive toughening agent significantly reduced the melt index of the system, and the toughening agent aggregated itself and was poorly dispersed, which resulted in poor appearance of the injection molded part.

[0061] Comparative Example 5, using EMA toughening agent, cannot achieve the required toughness.

Claims

1. A PCR-PET composition, characterized in that: By weight, it includes the following components: PCR-PET resin 78-88 parts; 12-20 parts of toughening agent; Nucleating agent 0.2-0.8 parts; Antioxidant 0-0.5 parts.

2. The PCR-PET composition according to claim 1, characterized in that The yellow flake content of the PCR-PET resin is ≤2000ppm, preferably, the yellow flake content of the PCR-PET resin is 100-1200ppm.

3. The PCR-PET composition according to claim 2, characterized in that The yellow flakes are PCR-PET fragments that turn yellow, darken in color, become carbonized and sticky, and / or have grease precipitated on the surface after being baked at 220° C. for 50 minutes.

4. The PCR-PET composition according to claim 1, characterized in that The PCR-PET resin is derived from PET bottles recycled after consumption, including mineral water bottles, beverage bottles, oil bottles, cosmetic bottles or medicine bottles.

5. The PCR-PET composition according to claim 1, characterized in that The toughening agent is selected from any one or more of E-MA-GMA or E-BA-GMA.

6. The PCR-PET composition according to claim 3, characterized in that The GMA grafting content in the toughening agent is 5-10%, preferably 7-9%.

7. The PCR-PET composition according to claim 1, characterized in that The nucleating agent is selected from one of sodium montmorillonite soap, calcium montmorillonite soap or amino acid calcium soap.

8. The PCR-PET composition according to claim 1, characterized in that The antioxidant is selected from at least one of hindered phenol antioxidants, phosphite antioxidants or thioether antioxidants.

9. The method for preparing the PCR-PET composition according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: adding each component into a mixer according to a proportion and mixing evenly to obtain a premix; the premix is ​​melt-extruded at 190-270° C. by a twin-screw extruder, cooled, and granulated to prepare a PCR-PET composite.

10. Use of the PCR-PET composition according to any one of claims 1 to 8 in the field of household appliances.

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