A high-density polyethylene for daily chemical packaging, a preparation method thereof, and an application thereof

Abstract

The present invention discloses a high-density polyethylene for daily chemical packaging. The raw materials for preparation include, by weight, 100-110 parts of white recycled plastic and 2-3 parts of an antioxidant. The preparation method includes the steps of sorting, shredding, cleaning, dehydrating, crushing and deodorizing, filtering, and granulation. The present invention improves the safety level of the recycled polyethylene by optimizing the production process of recycled plastic, enabling it to meet the requirements for daily chemical product packaging. By developing and improving the extrusion granulation process, the apparent performance of the recycled polyethylene is improved, and the product appearance quality is significantly enhanced.

Description

Technical Field

[0001] The present invention relates to a high-density polyethylene for daily chemical packaging, a preparation method and an application thereof, and is mainly used in the field of preparing daily chemical product packaging from recycled plastics. Background Art

[0002] With the complete ban on the import of waste plastics and a significant increase in public environmental awareness, the production of recycled plastics has shifted from high quantity to high quality. This is especially true for plastics used in daily chemical packaging, where high quality requirements are placed on the safety level, molding stability, final product performance, and product appearance of recycled plastics. Currently, the sources of these recycled plastic substrates are complex, with wide fluctuations in quality. The products produced are primarily used in low-end, cost-saving industries. Processing technologies used in the production process are outdated, resulting in low safety and stability. The supporting equipment and processes do not meet high-quality requirements. Therefore, the development of a recycling process for daily chemical packaging is crucial. Summary of the Invention

[0003] In order to improve the cleanliness and safety level of recycled plastics so that they can meet the requirements of daily chemical product packaging, the first aspect of the present invention provides a high-density polyethylene for daily chemical packaging, and the raw materials for preparation include, by weight: 100-110 parts of white recycled plastics and 2-3 parts of antioxidants.

[0004] As a preferred embodiment, the white recycled plastic is selected from one or a combination of milk bottles, white daily cleaning packaging bottles, mineral water barrels, wine barrels, urea barrels, and dialysis barrels.

[0005] As a preferred embodiment, the antioxidant is selected from 2,8-di-tert-butyl-4-methylphenol, octadecyl propionate, diaryl secondary amine, N-phenyl-N'-isopropyl-p-phenylenediamine, phosphite, dilauryl thiodipropionate, tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester, β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate n-octadecyl alcohol ester or a combination of several thereof.

[0006] A second aspect of the present invention provides a method for preparing high-density polyethylene for daily chemical packaging, comprising the following steps:

[0007] (1) Pretreatment: sorting, shredding, cleaning and dehydrating the white recycled plastic to obtain clean white recycled plastic;

[0008] (2) Crushed material deodorization: Use vacuum drying and deodorization equipment to crush and deodorize clean white recycled plastics;

[0009] (3) Filtration: The crushed white recycled plastic is melted and mixed at 150-220°C and filtered using a 200 mesh filter;

[0010] (4) Granulation: Add the filtered white recycled plastic melt and antioxidant into a single-screw extruder, perform vacuum treatment, the vacuum degree is 0.08-0.1MPa, and cool to granulate.

[0011] As a preferred embodiment, the cleaning in step 1 includes floating and sinking cleaning, grinding cleaning, and hot steam-tank cleaning.

[0012] As a preferred embodiment, the floating and sinking cleaning is to add hot water in the cleaning pool, the temperature of the hot water is 60-90° C., and then add alkali and cleaning agent.

[0013] As a preferred embodiment, the polishing and cleaning is performed by using turbine friction cleaning, followed by the steps of flotation, scraping, compression, filtration, and dehydration.

[0014] As a preferred embodiment, the hot steam-tank cleaning is carried out in a manner of four tanks connected in series and / or two tanks connected in parallel.

[0015] As a preferred embodiment, the dehydration in step 1 is to use clean water to wash out the alkali, detergent and pollutants on the surface of the white recycled plastic, and then use a centrifuge to dehydrate and dry it, and then inject hot air to further heat, dehumidify and dry it.

[0016] The third aspect of the present invention provides an application of the high-density polyethylene for daily chemical packaging, which is used in the packaging of cleaning products, cosmetics, and skin care products.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) The high-density polyethylene for daily chemical packaging of the present invention improves the safety level of the recycled polyethylene by optimizing the production and preparation process of recycled plastics, so that it can meet the requirements for being suitable for daily chemical product packaging.

[0019] (2) The high-density polyethylene used for daily chemical packaging described in the present invention improves the apparent performance of the recycled polyethylene by developing and improving the extrusion granulation process, and the appearance quality of the product is greatly improved.

[0020] (3) The high-density polyethylene for daily chemical packaging of the present invention avoids yellowing of recycled plastics by optimizing the appropriate cleaning temperature and using an antioxidant, while improving the controllability of the experimental process. DETAILED DESCRIPTION

[0021] In order to improve the cleanliness and safety level of recycled plastics so that they can meet the requirements of daily chemical product packaging, the first aspect of the present invention provides a high-density polyethylene for daily chemical packaging, and the raw materials for preparation include, by weight: 100-110 parts of white recycled plastics and 2-3 parts of antioxidants.

[0022] As a preferred embodiment, the white recycled plastic is selected from one or a combination of milk bottles, white daily cleaning packaging bottles, mineral water barrels, wine barrels, urea barrels, and dialysis barrels.

[0023] As a preferred embodiment, the antioxidant is selected from 2,8-di-tert-butyl-4-methylphenol, octadecyl propionate, diaryl secondary amine, N-phenyl-N'-isopropyl-p-phenylenediamine, phosphite, dilauryl thiodipropionate, tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester, β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate n-octadecyl alcohol ester or a combination of several thereof.

[0024] As a preferred embodiment, the antioxidant is a combination of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and phosphite.

[0025] As a preferred embodiment, the weight ratio of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] to phosphite is 1:(2-3).

[0026] A second aspect of the present invention provides a method for preparing high-density polyethylene for daily chemical packaging, comprising the following steps:

[0027] (1) Pretreatment: sorting, shredding, cleaning and dehydrating the white recycled plastic to obtain clean white recycled plastic;

[0028] (2) Crushed material deodorization: Use vacuum drying and deodorization equipment to crush and deodorize clean white recycled plastics;

[0029] (3) Filtration: The crushed white recycled plastic is melted and mixed at 150-220°C and filtered using a 200 mesh filter;

[0030] (4) Granulation: Add the filtered white recycled plastic melt and antioxidant into a single-screw extruder, perform vacuum treatment, the vacuum degree is 0.08-0.1MPa, and cool to granulate.

[0031] As a preferred embodiment, the shredded particles in step 1 have a diameter of 45-55 mm.

[0032] As a preferred embodiment, the cleaning in step 1 includes floating and sinking cleaning, grinding cleaning, and hot steam-tank cleaning.

[0033] As a preferred embodiment, the floating and sinking cleaning is to add hot water in the cleaning pool, the temperature of the hot water is 60-90° C., and then add alkali and cleaning agent.

[0034] As a preferred embodiment, the base is selected from one or a combination of sodium carbonate, sodium bicarbonate, and sodium hydroxide.

[0035] As a preferred embodiment, the cleaning agent is selected from one or a combination of plastic cleaning agents FRB-111, FRB-121, FRB-122, FRB-131, FRB-141, FRB-142, and FRB-143.

[0036] As a preferred embodiment, the polishing and cleaning is performed by using turbine friction cleaning, followed by the steps of flotation, scraping, compression, filtration, and dehydration.

[0037] As a preferred embodiment, the hot steam-tank cleaning is carried out in a manner of four tanks connected in series and / or two tanks connected in parallel.

[0038] As a preferred embodiment, the four tanks are connected in series for 1-2 minutes per tank, for a total of 5-8 minutes; and the two tanks are connected in parallel for 30-60 minutes.

[0039] As a preferred embodiment, the steam temperature of the hot steam-tank cleaning is 140-150° C. and the steam pressure is 0.7 MPa.

[0040] During the experiment, the applicant found that the water temperature for hot water washing is 60-90°C, and using steam heating can achieve a higher whiteness of the recycled plastic. The present application uses a boiler to prepare steam to heat the washing water. The high thermal enthalpy of steam can achieve rapid heating of the water. The steam generated is saturated steam with a pressure of 0.7MPa and a temperature of 140-150°C. If the washing water temperature is too high, it may cause the washed plastic to yellow. If the washing water is directly heated, the temperature increase is not easy to control and it is easy to cause the washing water to boil, causing local overheating of the washing water and yellowing of some recycled plastics. Using steam heating can avoid such problems, achieving both rapid heating of the washing water and avoiding the yellowing problem of some recycled plastics.

[0041] As a preferred embodiment, the dehydration in step 1 is to use clean water to wash out the alkali, detergent and pollutants on the surface of the white recycled plastic, and then use a centrifuge to dehydrate and dry it, and then inject hot air to further heat, dehumidify and dry it.

[0042] As a preferred embodiment, the rotation speed of the centrifuge is 800-1000 r / min, and the time is 15-20 min.

[0043] As a preferred embodiment, the filtration in step 3 includes backwash melt filtration and laser filtration.

[0044] The third aspect of the present invention provides an application of the high-density polyethylene for daily chemical packaging, which is used in the packaging of cleaning products, cosmetics, and skin care products.

[0045] The present invention is described in detail below by way of examples. Unless otherwise specified, all raw materials used are commercially available and are not particularly limited to the specific manufacturers from which they are purchased.

[0046] Example 1

[0047] A high-density polyethylene for daily chemical packaging is prepared from raw materials comprising, by weight, 110 parts of white recycled plastic and 3 parts of an antioxidant.

[0048] The white recycled plastics are milk bottles, white daily cleaning and care packaging bottles, and mineral water barrels, with a weight ratio of 1:3:2, purchased from Shanghai Ruiju Environmental Protection Technology Co., Ltd.

[0049] The antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and phosphite, with a weight ratio of 1:2.5.

[0050] A method for preparing high-density polyethylene for daily chemical packaging comprises the following steps:

[0051] (1) Pretreatment: sorting, shredding, cleaning and dehydrating the white recycled plastic to obtain clean white recycled plastic;

[0052] (2) Crushed material deodorization: Use vacuum drying and deodorization equipment to crush and deodorize clean white recycled plastics;

[0053] (3) Filtration: The crushed white recycled plastic was melted and mixed at 200°C and filtered using a 200 mesh filter;

[0054] (4) Granulation: Add the filtered white recycled plastic melt and antioxidant into a single-screw extruder, perform vacuum treatment, the vacuum degree is 0.08MPa, and cool to granulate.

[0055] The shredded particle size in step 1 is 50 mm.

[0056] The cleaning in step 1 includes floating and sinking cleaning, grinding cleaning, and hot steam-tank cleaning.

[0057] The floating and sinking cleaning is to add hot water to the cleaning pool, the temperature of the hot water is 80°C, then add sodium carbonate and sodium bicarbonate, the weight ratio of sodium carbonate to sodium bicarbonate is 1:2, and then add plastic cleaning agent FRB-111 purchased from Yuman Industrial Co., Ltd.

[0058] The grinding and cleaning is performed by using turbine friction cleaning, followed by the steps of air flotation, scraping, compression, filtering and dehydration.

[0059] The hot steam-tank cleaning method is to first connect four tanks in series and then connect two tanks in parallel. The steam temperature is 145°C, the steam pressure is 0.7 MPa, the four tanks in series time is 1.5 minutes per tank, and the total time is 6 minutes; the two tanks in parallel time is 45 minutes.

[0060] The dehydration is to use clean water to wash out the alkali, detergent and pollutants on the surface of the white recycled plastic, and then use a centrifuge to dehydrate and dry it, and then inject hot air to further heat, dehumidify and dry it. The speed of the centrifuge is 1000r / min and the time is 15min.

[0061] The filtration in step 3 is performed in sequence by backwashing melt filtration and laser filtration.

[0062] Example 2

[0063] A high-density polyethylene for daily chemical packaging is prepared from raw materials comprising, by weight, 100 parts of white recycled plastic and 2.5 parts of an antioxidant.

[0064] The white recycled plastics are white daily cleaning and care packaging bottles, wine barrels, and urea barrels, with a weight ratio of 2:1:1, purchased from Shanghai Ruiju Environmental Protection Technology Co., Ltd.

[0065] The antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and dilauryl thiodipropionate, with a weight ratio of 1:2.5.

[0066] A method for preparing high-density polyethylene for daily chemical packaging comprises the following steps:

[0067] (1) Pretreatment: sorting, shredding, cleaning and dehydrating the white recycled plastic to obtain clean white recycled plastic;

[0068] (2) Crushed material deodorization: Use vacuum drying and deodorization equipment to crush and deodorize clean white recycled plastics;

[0069] (3) Filtration: The crushed white recycled plastic was melted and mixed at 190°C and filtered using a 200 mesh filter;

[0070] (4) Granulation: Add the filtered white recycled plastic melt and antioxidant into a single-screw extruder, perform vacuum treatment, the vacuum degree is 0.08MPa, and cool to granulate.

[0071] The shredded particle size in step 1 is 50 mm.

[0072] The cleaning in step 1 includes floating and sinking cleaning, grinding cleaning, and hot steam-tank cleaning.

[0073] The floating and sinking cleaning is to add hot water to the cleaning pool, the temperature of the hot water is 90°C, then add sodium carbonate and sodium bicarbonate, the weight ratio of sodium carbonate to sodium bicarbonate is 1:2, and then add plastic cleaning agent FRB-143 purchased from Yuman Industrial Co., Ltd.

[0074] The grinding and cleaning is performed by using turbine friction cleaning, followed by the steps of air flotation, scraping, compression, filtering and dehydration.

[0075] The hot steam-tank cleaning method is to first connect four tanks in series and then connect two tanks in parallel. The steam temperature is 150°C, the steam pressure is 0.7MPa, the four tanks in series time is 2 minutes per tank, a total of 8 minutes; the two tanks in parallel time is 55 minutes.

[0076] The dehydration is to use clean water to wash out the alkali, detergent and pollutants on the surface of the white recycled plastic, and then use a centrifuge to dehydrate and dry it, and then inject hot air to further heat, dehumidify and dry it. The speed of the centrifuge is 900r / min and the time is 20min.

[0077] The filtration in step 3 is performed in sequence by backwashing melt filtration and laser filtration.

[0078] Example 3

[0079] A high-density polyethylene for daily chemical packaging, a preparation method, and an application thereof. The specific steps are the same as those in Example 1, except that the antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

[0080] Example 4

[0081] A high-density polyethylene for daily chemical packaging, a preparation method and an application thereof. The specific steps are the same as those in Example 1, except that the washing water is heated by direct boiler heating.

[0082] Example 5

[0083] A high-density polyethylene for daily chemical packaging, a preparation method, and an application thereof. The specific steps are the same as those in Example 1, except that the base is sodium bicarbonate.

[0084] Performance testing:

[0085] 1. Whiteness: The prepared samples were tested according to GB 2913-1982.

[0086] 2. Black spot area and black spot diameter: Randomly select 50 prepared samples and measure the black spot area and black spot diameter.

[0087] 3. Odor: The prepared samples were tested according to VW50180 standard.

[0088] The examples were tested according to the above standards, and the results are shown in Table 1.

[0089] Table 1

[0090] Whiteness <![CDATA[Black dot area / mm 2 > Black spot diameter / mm odor Example 1 90 0.007 0.08 Level 2 Example 2 88 0.01 0.1 Level 3 Example 3 81 0.011 0.11 Level 3 Example 4 82 0.012 0.14 Level 3 Example 5 84 0.01 0.12 Level 3

Claims

1. A high-density polyethylene for daily chemical packaging, characterized in that: The raw materials for the preparation include, by weight: 100-110 parts of white recycled plastic, 2-3 parts of antioxidant; The white recycled plastic is selected from one or a combination of milk bottles, white daily cleaning packaging bottles, mineral water barrels, wine barrels, urea barrels, and dialysis barrels; The antioxidant is a combination of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and phosphite, with a weight ratio of 1:2.5; The method for preparing high-density polyethylene for daily chemical packaging comprises the following steps: (1) Pretreatment: sorting, shredding, cleaning and dehydrating the white recycled plastic to obtain clean white recycled plastic; (2) Crushed material deodorization: Use vacuum drying and deodorization equipment to crush and deodorize clean white recycled plastics; (3) Filtration: The crushed white recycled plastic is melted and mixed at 150-220°C and filtered using a 200 mesh filter; (4) Granulation: Add the filtered white recycled plastic melt and antioxidant into a single-screw extruder, perform vacuum treatment, the vacuum degree is 0.08-0.1MPa, and cool to granulate; The cleaning in step 1 includes floating and sinking cleaning, grinding cleaning, and hot steam-tank cleaning; The polishing and cleaning is performed by using turbine friction cleaning, followed by flotation, scraping, compression, filtration, and dehydration steps; The floating and sinking cleaning is to add hot water in the cleaning tank, the temperature of the hot water is 80°C, and then add alkali and cleaning agent; The alkali is sodium carbonate and sodium bicarbonate, and the weight ratio of sodium carbonate to sodium bicarbonate is 1:2; The hot steam-tank cleaning method is to first connect four tanks in series and then connect two tanks in parallel. The steam temperature is 145°C, the steam pressure is 0.7 MPa, and the four tanks in series are connected for 1.5 minutes each, for a total of 6 minutes; the two tanks in parallel are connected for 45 minutes. The dehydration in step 1 is to use clean water to wash out the alkali, detergent and pollutants on the surface of the white recycled plastic, and then use a centrifuge to dehydrate and dry it, and then inject hot air to further heat, dehumidify and dry it. The speed of the centrifuge is 1000r / min and the time is 15min.

2. A method for preparing high-density polyethylene for daily chemical packaging according to claim 1, characterized in that: The following steps are involved: (1) Pretreatment: sorting, shredding, cleaning and dehydrating the white recycled plastic to obtain clean white recycled plastic; (2) Crushed material deodorization: Use vacuum drying and deodorization equipment to crush and deodorize clean white recycled plastics; (3) Filtration: The crushed white recycled plastic is melted and mixed at 150-220°C and filtered using a 200 mesh filter; (4) Granulation: Add the filtered white recycled plastic melt and antioxidant into a single-screw extruder, perform vacuum treatment, the vacuum degree is 0.08-0.1MPa, and cool to granulate.

3. An application of high-density polyethylene for daily chemical packaging according to claim 1, characterized in that: Used in the packaging of cleaning products, cosmetics, and skin care products.