Regenerated polypropylene composite material as well as preparation method and application thereof

Abstract

The invention discloses a regenerated polypropylene composite material which comprises the following components in parts by weight: 100 parts of regenerated polypropylene; 0.05 to 0.3 part of a fluorescence eliminating agent; the fluorescence eliminating agent is a composition of 5 (6)-carboxyl fluorescein diacetate N-succinimide ester and superoxide dismutase, and the weight ratio of the 5 (6)-carboxyl fluorescein diacetate N-succinimide ester to the superoxide dismutase is 1: (0.05-0.2). The residual fluorescent agent after the regenerated polypropylene is purified can be eliminated through the fluorescence eliminating agent, the problem that residual fluorescent light of the regenerated polypropylene after cleaning treatment cannot be recycled is solved, and the method can be particularly applied to food contact regenerated polypropylene composite materials such as daily chemical packages and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly to a recycled polypropylene composite material, a preparation method thereof, and an application thereof. Background Art

[0003] Waste plastics are difficult to decompose in the natural environment, and the fragmentation during the decomposition process causes more serious secondary pollution. Therefore, today, with the increasingly deteriorating human ecological environment, the recycling of recycled plastics has attracted more and more attention. Polypropylene has become one of the most widely used resins in production and life due to its stable polymerization process, rich products, and high cost performance. In recent years, with the rapid development of the national economy, the packaging levels in various industries have been improved to varying degrees, which is mainly reflected in industries such as food, dairy drinks, daily chemicals, and medicine. In such a rapidly developing market, the role of packaging is becoming increasingly obvious, and packaging has also been increasingly concerned by more daily chemical enterprises. From quality to design, from transportation to sales, packaging has been raised to an unprecedented height.

[0004] Plastic bottle packaging can be divided into transparent, semi-transparent, and opaque types, which can well display the characteristics of different products and are deeply loved by daily chemical manufacturers. Therefore, in recent years, the form of plastic bottle packaging has gradually become rich, and the design is unique in shape. However, for recycled PP products in transparent and semi-transparent products, certain fluorescent substances often remain, so they cannot be recycled well.

[0005] However, there are few records in the prior art regarding methods for eliminating fluorescent agents in PP. Summary of the Invention

[0006] The purpose of the present invention is to provide a recycled polypropylene composite material that eliminates fluorescence.

[0007] The present invention is achieved through the following technical solutions: A recycled polypropylene composite material, by weight, comprises the following components: 100 parts of recycled polypropylene; 0.05 - 0.3 parts of a fluorescence eliminator; The fluorescence eliminator is a mixture of 5(6)-carboxyfluorescein N-succinimidyl ester and superoxide dismutase, and the weight ratio is 1:(0.05 - 0.2).

[0008] Preferably, the weight ratio of 5(6)-carboxyfluorescein N-succinimidyl ester to superoxide dismutase is 1:(0.08 - 0.1).

[0009] The recycled polypropylene is polypropylene resin obtained by recycling; the recycled polypropylene is selected from at least one of recycled homopolypropylene and recycled copolymer polypropylene.

[0010] The CAS number of the fluorescein diacetate N-succinimidyl ester is: 150347-59-4.

[0011] The CAS number of the superoxide dismutase is 9054-89-1.

[0012] After eliminating the fluorescence, the fluorescein diacetate N-succinimidyl ester will decompose and leave the succinimidyl ester functional group, and this characteristic peak can be detected by infrared spectroscopy.

[0013] Whether to add 0-10 parts of toughening agent can be selected according to actual needs. The toughening agent can be ethylene-octene copolymer.

[0014] Whether to add 0-2 parts of additives can be selected according to actual needs. The additives are selected from at least one of antioxidants and lubricants.

[0015] The antioxidant can be a compound of hindered phenol and phosphite; the lubricant can be calcium stearate.

[0016] The fluorescent agents usually contained in recycled polypropylene mainly include three categories: stilbene-type fluorescent agents, naphthalimide-type fluorescent agents, and coumarin-type fluorescent agents. The typical representatives of each category are: The representative of the stilbene-type fluorescent agent is:

[0017] The representative of the naphthalimide-type fluorescent agent is:

[0018] The representative of the coumarin-type fluorescent agent is:

[0019] The above three types of fluorescent agents all produce fluorescence through conjugated double bonds to achieve the effects of enhancing the light brightness of the product and whitening with a blue phase. After these substances are added to the resin, the fluorescence residue cannot be completely eliminated without a decomposition aid with a special structure to break the double bond. And the fluorescent quencher of the present invention has excellent quenching effects on the above fluorescent agents.

[0020] The preparation method of the recycled polypropylene composite material of the present invention includes the following steps: according to the ratio, mix each component evenly, and extrude and pelletize through a twin-screw extruder. The temperature range of the screw is 180-230 °C to obtain the recycled polypropylene composite material.

[0021] The application of the recycled polypropylene composite material of the present invention is used for preparing daily chemical packaging parts.

[0022] The present invention has the following beneficial effects: In the present invention, a specific structure is formed by the combination of a fluorescence quencher 5(6)-carboxyfluorescein N-succinimidyl ester and a fluorescent substance. Superoxide dismutase locks the fluorescent substance through the succinimidyl ester and decomposes the conjugated double bonds in the fluorescence in a targeted manner. Thus, the residual fluorescence in recycled polypropylene is decomposed efficiently and directionally, solving the problem that the recycled polypropylene with residual fluorescence after cleaning treatment cannot be recycled, especially being applicable to food-contact recycled polypropylene composite materials such as daily chemical packaging. Detailed Embodiments

[0023] The following examples are given to specifically describe the present invention. It is necessary to point out here that the following examples are only used to further illustrate the present invention and should not be construed as limiting the protection scope of the present invention. Some non-essential improvements or adjustments made by those of ordinary skill in the art to the present invention based on these examples still fall within the protection scope of the present invention.

[0024] The raw materials used in the examples and comparative examples are as follows: 5(6)-Carboxyfluorescein N-succinimidyl ester (abbreviated as carboxyhydroxy compound in the table): Merck Life Science; Superoxide dismutase: Merck Life Science; Recycled polypropylene 1: Transparent lunch box crushed material, with a polypropylene content of 98% and strong fluorescence; Recycled polypropylene 2: Transparent lunch box crushed material, with a polypropylene content of 99% and strong fluorescence; Recycled polypropylene 3: White fruit basket crushed material, with a polypropylene content of 99.5% and strong fluorescence; Recycled polypropylene 4: White water pipe crushed material, with a polypropylene content of 99% and strong fluorescence; Antioxidant: A compound mixture of hindered phenol antioxidant 1010 and phosphite antioxidant 168 mixed at a ratio of 1:2, commercially available.

[0025] Lubricant: Calcium stearate lubricant, commercially available.

[0026] Preparation method of the polypropylene composite materials in the examples and comparative examples: According to the ratio, each component is mixed evenly and extruded and pelletized through a twin-screw extruder. The temperature range of the screw is 180 - 230 °C to obtain the recycled polypropylene composite materials.

[0027] Test methods for each item: (1) Tensile strength: GB / T 1040.1 - 2018.

[0028] (2) Izod impact strength, type A notch: GB / T1843 - 2008.

[0029] (3)Fluorescence residue: After injection molding into square plates, observe whether there is fluorescence under the UV lamp of the color matching light box with the naked eye. The visual fluorescence ranges from weak to strong as no fluorescence, slight fluorescence, weak fluorescence, and strong fluorescence in turn.

[0030] Table 1: Recycled polypropylene composites of Examples 1-7 (parts by weight) and test results Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Recycled Polypropylene 1 100 100 100 100 Recycled Polypropylene 2 100 Recycled Polypropylene 3 100 Recycled Polypropylene 4 100 Carboxyhydroxy Compound 0.046 0.046 0.046 0.046 0.047 0.045 0.042 Superoxide Dismutase 0.004 0.004 0.004 0.004 0.003 0.005 0.008 Antioxidant 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Lubricant 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Tensile Strength, MPa 32 33 28 26 32 32 32 <![CDATA[Izod impact strength of cantilever beam, kJ / m 3 > 2.6 2.7 12.8 13.6 2.5 2.6 2.7 Fluorescence Residue None None None None Micro Fluorescence None Micro Fluorescence As can be seen from Examples 1-4, the fluorescence eliminator of the present application is generally applicable to polypropylene waste in the prior art.

[0031] As can be seen from Examples 1 / 5-7, under the same addition amount of the fluorescence eliminator, the fluorescence elimination effect is better under the preferred fluorescence eliminator ratio.

[0032] Table 2: Recycled polypropylene composites of Examples 8-11 (parts by weight) and test results Example 8 Example 9 Example 10 Example 11 Recycled Polypropylene 1 100 100 100 100 Carboxyhydroxy Compound 0.094 0.185 0.278 0.046 Superoxide Dismutase 0.006 0.015 0.022 0.004 Antioxidant 0.2 0.2 0.2 Lubricant 0.2 0.2 0.2 Tensile Strength, MPa 32 32 32 32 <![CDATA[Izod impact strength of cantilever beam, kJ / m 3 > 2.6 2.7 2.6 2.5 Fluorescence Residue None None None None Table 3: Recycled polypropylene composites of comparative examples (parts by weight) and test results Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Recycled Polypropylene 1 100 100 100 100 Recycled Polypropylene 2 100 Carboxyhydroxy Compound 0 0.1 0 0.002 Superoxide Dismutase 0 0.1 0 0.001 Antioxidant 0.2 0.2 0.2 0.2 0.2 Lubricant 0.2 0.2 0.2 0.2 0.2 Tensile Strength, MPa 32 32 33 28 32 <![CDATA[Izod impact strength of cantilever beam, kJ / m 3 > 2.6 2.6 2.7 2.6 2.5 Fluorescence Residue Strong Fluorescence Strong Fluorescence Strong Fluorescence Strong Fluorescence Weak Fluorescence As can be seen from Examples 1-3, adding carboxyhydroxyl compounds or superoxide dismutase alone cannot effectively eliminate fluorescence.

Claims

1. A recycled polypropylene composite material, characterized in that, by weight, it comprises the following components: 100 parts of recycled polypropylene; 0.05 - 0.3 parts of a fluorescence eliminator; The fluorescence eliminator is a mixture of 5(6)-carboxyfluorescein diacetate N-succinimidyl ester and superoxide dismutase, and the weight ratio is 1:(0.05 - 0.2).

2. The recycled polypropylene composite material according to claim 1, characterized in that, the weight ratio of 5(6)-carboxyfluorescein diacetate N-succinimidyl ester to superoxide dismutase is 1:(0.08 - 0.10).

3. The recycled polypropylene composite material according to claim 1, characterized in that, the recycled polypropylene is a polypropylene resin obtained by recycling; the recycled polypropylene is selected from at least one of recycled homopolypropylene and recycled copolymer polypropylene.

4. The recycled polypropylene composite material according to claim 1, characterized in that, the CAS number of the 5(6)-carboxyfluorescein diacetate N-succinimidyl ester is: 150347-59-4.

5. The recycled polypropylene composite material according to claim 1, characterized in that, the CAS number of the superoxide dismutase is 9054-89-1.

6. The recycled polypropylene composite material according to claim 1, characterized in that, by weight, it further comprises 0 - 10 parts of a toughening agent.

7. The recycled polypropylene composite material according to claim 1, characterized in that, by weight, it further comprises 0.01 - 2 parts of an auxiliary agent, and the auxiliary agent is selected from at least one of an antioxidant and a lubricant.

8. The preparation method of the recycled polypropylene composite material according to any one of claims 1 - 7, characterized in that, it comprises the following steps: according to the ratio, mix each component evenly, and extrude and pelletize through a twin-screw extruder, and the screw temperature range is 180 - 230 °C to obtain the recycled polypropylene composite material.

9. The application of the recycled polypropylene composite material according to any one of claims 1 - 7, characterized in that, it is used for preparing daily chemical packaging parts.