CN114378981A

CN114378981A - Water-carrying porous friction medium and method for cleaning waste plastic

Info

Publication number: CN114378981A
Application number: CN202111520775.8A
Authority: CN
Inventors: 吴剑波; 陈宁; 麻一明
Original assignee: Ningbo Jianfeng New Material Co ltd
Current assignee: Ningbo Jianfeng New Material Co ltd
Priority date: 2021-12-14
Filing date: 2021-12-14
Publication date: 2022-04-22
Anticipated expiration: 2041-12-14
Also published as: CN114378981B

Abstract

The invention belongs to the technical field of plastic recovery, and discloses a brand-new water-carrying porous friction medium and a waste plastic cleaning method by taking the cleaning of an ABS material of a refrigerator as an example. The refrigerator ABS crushed material obtained by cleaning the ABS door liner and the ABS liner by using the method for cleaning waste plastics by using the water-carrying porous friction medium is used for preparing a regenerated ABS plastic particle material which shows good mechanical properties.

Description

Water-carrying porous friction medium and method for cleaning waste plastic

Technical Field

The invention belongs to the technical field of plastic recovery, and particularly relates to a water-carrying porous friction medium and a method for cleaning waste plastics.

Background

As is well known, plastic products are ubiquitous in our lives, and the plastic products full of Linnauno also generate a great amount of white pollution while being widely applied, so that the ecological environment of the earth is greatly damaged, and the sustainable development of the global ecology is hindered. The annual production of waste plastics in China is more than 3000 ten thousand tons, and the regeneration utilization rate accounts for 70 percent or more. In addition to the full utilization of plastic products as many times as possible, recycling of waste plastics is also of paramount importance.

In the physical mechanical recycling method of waste plastics, a water washing method is basically adopted at present, which can ensure the control of problems in the cleaning process, but wastes a large amount of water resources, generates a large amount of waste water at the same time, has high treatment cost and energy consumption of the waste water, and further pollutes the environment if the waste water is not effectively treated. The waste plastic is cleaned by the dry method, hard solids and the waste plastic rotate in a high-speed rotating cylinder, and pollutants on the surface of the waste plastic are removed by friction between the hard solids and blades in the rotating cylinder and the waste plastic. This method generates a large amount of heat during the cleaning process due to high speed friction, because the heat cannot be removed under dry conditions, accumulates in the cleaning system, causes problems of softening and caking of the waste plastics, and the cleaned plastics are aged by thermal oxygen at higher temperatures, resulting in reduced performance.

The invention patent CN107379321B discloses a method for cleaning and recycling waste plastics without water, which mainly adds hard inorganic matters and auxiliary dry powder stripping agent into waste plastic powder, rotates in a horizontal rotary cylinder in a dry state, and strips mud, grease and ink on the surface of the waste plastic powder by utilizing the micro-friction grinding action generated by hard inorganic particles through the activation of the stripping agent on high-adhesion impurities such as grease and ink. However, the dry friction cleaning of the technology is low in speed, long friction time is needed for low-speed friction cleaning, the efficiency is low, and meanwhile, more and more heat is generated along with the increase of the friction cleaning time, so that the temperature of the friction cleaning waste plastic is increased, thermal oxidation aging is easily caused, and even when the temperature exceeds the heat resistance temperature (HDT) of the material, the friction cleaning waste plastic is softened and agglomerated. In addition, the cleaning scheme of the invention adopts a large amount of alkaline stripping agent, which is an environmentally-friendly cleaning mode.

In addition, the other more friction cleaning machines only utilize the physical acting force of the extrusion and rotation of the screw rod to achieve the purpose of friction separation, and the separation and cleaning effect is poor. Therefore, how to effectively recycle the waste plastics under the condition of no pollution, and improve the recycling efficiency and the recycling quality of the waste plastics is an important problem which needs to be solved urgently in the plastic industry at present.

Disclosure of Invention

The invention aims to provide a water-carrying porous friction medium material which is used for friction cleaning of waste plastics, realizes dry cleaning without waste water generation, effectively controls the friction cleaning temperature, and realizes the waste plastic cleaning effects with no pollution, high quality and high efficiency.

A water-carrying porous friction medium is prepared from porous hard material through immersing or spraying it in water, and fully absorbing water. The porous hard material is one or more of steel slag, porous silicon carbide, alumina hollow spheres, porous titanium oxide, porous stainless steel, porous titanium and porous nickel with the particle size of more than or equal to 3mm, and is irregular in shape, preferably particles with edges and corners.

A method for cleaning waste plastics by using water-carrying porous friction media is provided, which takes the cleaning of acrylonitrile-butadiene-styrene (ABS) materials of a refrigerator as an example, and shows a brand-new friction cleaning media and a waste plastics cleaning method, and concretely comprises the following steps:

(1) placing the ABS door liner and the ABS inner container disassembled from the waste refrigerator into a crusher for crushing, and screening through a crushing chamber screen mesh and a discharging chamber screen mesh of the crusher to obtain ABS crushed rough materials with primarily filtered impurities and uniform sizes;

(2) mixing ABS broken wool and a water-carrying porous friction medium in a certain mass ratio, and rotationally cleaning in a high-speed friction cleaning machine at a rotating speed;

(3) screening the material obtained by high-speed rotational friction in a vibrating screen to separate out a water-carrying porous friction medium and a part of stripped foreign matters, wherein the screening remainder is a mixture of an ABS crushed material and the stripped foreign matters;

(4) and (3) putting the screened residues into a solid-solid separator, throwing the foreign bodies with smaller volume out of the filter screen under the centrifugal action of the solid-solid separator, and throwing the ABS crushed pieces with large volume out of an upper end outlet from the bottom to obtain the cleaned ABS crushed materials.

Further, the aperture of the screen mesh of the crushing chamber of the crusher in the step (1) is 6-20 mm, the aperture of the screen mesh of the discharging chamber of the crusher is 1-20 mm, and the magnetic frame is placed at the discharging port of the crusher. Plastics are broken when being less than the screen cloth aperture to the size, can pass from the screen cloth mesh department of broken room and drop to the discharge chamber in, and the screen cloth board landing through the discharge chamber is to the discharge gate, and foreign matters such as the plastics powder, earth, grit, iron fillings that are less than the screen cloth aperture can be removed by the screen at the landing in-process. Meanwhile, the magnetic frame is arranged at the discharge port of the crusher, so that magnetic metal ash can be effectively adsorbed and removed.

Further, the aperture of the screen mesh of the crushing chamber of the crusher in the step (1) must be larger than the aperture of the screen mesh of the discharge chamber of the crusher.

Further, the mass ratio of the ABS broken wool to the water-carrying porous friction medium in the step (2) is 1: (0.15-0.30).

Further, the rotating speed of the high-speed friction cleaning machine in the step (2) is 1000-1500 rpm, and the cleaning time is 3-15 min.

The invention adopts high-speed friction combined with irregular water-carrying porous friction medium particles, so that the refrigerator ABS crushed material scrapes and separates impurities such as glue, tinfoil, clay and the like on the surface in the high-speed friction grinding process. Bear the weight of moisture in the micropore of the porous friction medium that carries water, along with high-speed friction grinding material temperature rise, the moisture can volatilize and take away the heat, and the temperature in the effective control friction cleaning process avoids refrigerator ABS broken material at the friction in-process, takes place adhesion or caking because of the temperature rise, and moisture also can further prevent to produce dust pollution in the cleaning process simultaneously.

Further, the aperture of the screen mesh of the vibrating screen in the step (3) is between the particle size of the porous hard material and the aperture of the screen mesh of the crushing chamber of the crusher.

Further, the solid-solid separator in the step (4) is a centrifugal separator with a spiral rotating shaft and a screen cylinder, and the aperture of the mesh of the screen cylinder is 0-20 mm and must be smaller than the aperture of the screen of a discharge chamber of the crusher.

The invention uses the high-speed centrifugal action of the solid-solid separator, can quickly and continuously separate the foreign matters on the surface of the waste plastics, and simultaneously generates high-speed friction among materials to further strip the foreign matters on the surface of the waste plastics.

The refrigerator ABS crushed material obtained by cleaning the refrigerator ABS door liner and the ABS liner by using the method for cleaning the waste plastics by using the water-carrying porous friction medium is used for preparing a regenerated ABS plastic particle material, which comprises the following components in percentage by weight:

refrigerator ABS crushed material: 97.5 to 100.0 percent,

antioxidant: 0.0 to 0.5 percent,

other auxiliary agents: 0.0 to 2.0%.

Further, the antioxidant is one or more of pentaerythritol tetrakis (β - (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate), n-octadecyl β - (4-hydroxyphenyl-3, 5-di-tert-butyl) propionate, tris (2, 4-di-tert-butylphenyl) phosphite, ethyl 2, 2-thiobis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], 2-oxamido-bis [ ethyl-3- (3, 5-di-tert-butyl-4-hydroxyphenyl) ] propionate, 2, 6-di-tert-butyl-4-methylphenol, and dilauryl thiodipropionate.

Further, other auxiliary agents include antibacterial agents, antistatic agents, radium carving agents, lubricants, and coloring agents.

The preparation method of the regenerated ABS plastic particle material comprises the following steps:

s1, drying the cleaned ABS crushed material for later use;

s2, weighing the cleaned ABS crushed material, the antioxidant and other auxiliaries according to the weight percentage, and uniformly mixing to obtain a mixture;

and S3, putting the mixed material into a single-screw extruder through a feeding port for melt extrusion and granulation.

Further, the single screw extruder in step S3 has a vacuum port at the beginning of the melt section.

Further, the single screw extruder in the step S3 has 9 temperature control areas, wherein the temperature of the temperature control area 1-2 is 180-220 ℃, the temperature of the temperature control area 3-4 is 200-230 ℃, the temperature of the temperature control area 5-6 is 200-220 ℃, and the temperature of the temperature control area 7-9 is 210-240 ℃.

Compared with the prior art, the invention has the following advantages:

(1) the water-carrying porous friction medium prepared by the invention is prepared by taking porous hard material particles as a base material and fully absorbing water, has very good hardness, can generate friction with plastics, and peels off impurities such as glue, tinfoil, mud and the like on the surface of the plastics;

(2) the water carried in the water-carrying porous friction medium can effectively absorb heat generated in the friction process, control the temperature of materials in the friction process, prevent the plastic materials from caking after being softened, and further prevent dust pollution generated in the cleaning process due to the water;

(3) through the reasonable design of the screen meshes in the crusher, the friction cleaning machine, the vibrating screen and the solid-solid separator and the centrifugal and vibration principles, impurities in the waste plastics are effectively removed under the condition that the washing is not applicable;

(4) the high-speed centrifugal action of the solid-solid separator can quickly and continuously separate the foreign matters on the surface of the waste plastics and can further strip the foreign matters on the surface of the waste plastics;

(5) the method for cleaning the plastic adopts high-speed friction cleaning separation, is green and environment-friendly, has higher efficiency and good effect, and is suitable for industrial application.

Drawings

FIG. 1 is a schematic view of a solid-solid separator used in the present invention;

FIG. 2 is a photograph of a screen cylinder in a solids-solids separator;

in the figure: 1-spiral rotating shaft and 2-screen cylinder.

Detailed Description

The technical solutions of the present invention are further described and illustrated below by the specific embodiments and the drawings, it should be understood that the specific embodiments described herein are only for the understanding of the present invention, and are not intended to limit the present invention specifically. And the drawings used herein are for the purpose of illustrating the disclosure better and are not intended to limit the scope of the invention. The raw materials used in the examples of the present invention are those commonly used in the art, and the methods used in the examples are those conventional in the art, unless otherwise specified.

In the following examples and comparative examples, the ABS door liner and ABS inner container of the disassembled refrigerator are obtained from the household electrical appliance disassembling factory, the antioxidant is Irganox1076 and Irgafos168, which are antioxidants produced by Pasteur, Germany, and the mixture ratio of the main antioxidant and the auxiliary antioxidant is adopted, and the other auxiliary agent is titanium dioxide of KWA-101, which is a model number of Panzhike Wei mining industry, Inc.

Example 1

The waste plastic is cleaned by a method for high-speed grinding and stripping of a water-carrying porous friction medium, and the specific cleaning method comprises the following steps:

(1) placing the ABS door liner and the ABS inner container disassembled from the waste refrigerator into a crusher for crushing, and screening through a screen with 20mm mesh aperture in a crushing chamber of the crusher and a screen with 18mm mesh aperture in a discharging chamber of the crusher to obtain ABS crushed rough materials with primarily filtered impurities and uniform size;

(2) mixing ABS broken wool and a water-carrying steel slag friction medium with the particle size of 8mm according to the mass ratio of 1: 0.15 mixing, rotating in a high-speed friction cleaning machine at the rotating speed of 1500rpm for 15 min;

(3) screening the material obtained by high-speed rotary friction in a vibrating screen with the mesh opening diameter of 12mm, separating out the used water-carrying steel slag medium and part of stripped foreign matters, and mixing the crushed ABS and the stripped foreign matters as screening residues;

(4) and (3) putting the screened residues into a solid-solid separator with the mesh opening of the screen mesh of 2mm, centrifuging the small-volume glue, tinfoil, soil and other foreign bodies out of the filter screen under the centrifugal action of the solid-solid separator, and throwing the refrigerator ABS crushed pieces out of an upper end outlet from the bottom due to the large volume to obtain the clean refrigerator ABS crushed materials.

The water-carrying steel slag friction medium comprises the following specific water absorption steps: the steel slag is soaked in water for 20min and fully absorbs water.

The clean refrigerator ABS crushed material is adopted to prepare the regenerated ABS plastic particle material, and the steps are as follows:

s1, drying the cleaned refrigerator ABS crushed material for later use;

s2, weighing 99.20kg of cleaned ABS crushed material, Irganoc 10760.2kg of antioxidant, Irgafoss 1680.1kg of antioxidant and KWA-1010.5 kg of titanium dioxide according to weight percentage, and uniformly mixing to obtain a mixture;

s3, putting the mixed material into a single-screw extruder through a feeding port, controlling the frequency of a motor of the feeder to be 35Hz, setting the temperature of temperature control areas 1-2 to be 190 ℃ and 205 ℃ respectively, the temperature of temperature control areas 3-4 to be 210 ℃ and 210 ℃ respectively, the temperature of temperature control areas 5-6 to be 205 ℃ and 205 ℃ respectively, the temperature of temperature control areas 7-9 to be 215 ℃, 215 ℃ and 220 ℃ respectively, starting a vacuum pump, and performing melt extrusion granulation.

Example 2

Example 2 differs from example 1 in the method of washing waste plastic with water-laden porous friction media, as follows:

(1) placing the ABS door liner and the ABS inner container disassembled from the waste refrigerator into a crusher for crushing, and screening through a screen with 13mm of mesh aperture in a crushing chamber of the crusher and a screen with 8mm of mesh aperture in a discharging chamber of the crusher to obtain ABS crushed rough materials with primarily filtered impurities and uniform size;

(2) mixing ABS broken wool and a water-carrying steel slag friction medium with the particle size of 5mm according to the mass ratio of 1: 0.20 mixing, rotating in a high-speed friction cleaning machine at the rotating speed of 1200rpm for 8 min;

(3) screening the material obtained by high-speed rotary friction in a vibrating screen with the mesh opening diameter of 8mm, separating out the used water-carrying steel slag friction medium and part of stripped foreign matters, and mixing the screened remainder with ABS (acrylonitrile butadiene styrene) crushing and the stripped foreign matters;

Example 3

Example 3 differs from example 1 in the method of washing waste plastic with water-laden porous friction media, as follows:

(1) placing the ABS door liner and the ABS inner container disassembled from the waste refrigerator into a crusher for crushing, and screening through a screen with 6mm mesh aperture in a crushing chamber of the crusher and a screen with 4mm mesh aperture in a discharging chamber of the crusher to obtain ABS crushed rough materials with primarily filtered impurities and uniform size;

(2) mixing ABS broken wool and a water-carrying steel slag friction medium with the particle size of 3mm according to the mass ratio of 1: 0.30 mixing, rotating in a high-speed friction cleaning machine at the rotating speed of 1000rpm for 3 min;

(3) screening the material obtained by high-speed rotary friction in a vibrating screen with the screen hole diameter of 4mm, separating the used water-carrying steel slag friction medium and part of stripped foreign matters, and mixing the screened remainder of ABS crushing and the stripped foreign matters;

Example 4

Example 4 is different from example 2 only in that in step S2, 97.50kg of clean ABS broken material, Irganoc 10760.3 kg of antioxidant, Irgafos 1680.2 kg of antioxidant and KWA-1012.0 kg of titanium dioxide are weighed and mixed evenly according to weight percentage to obtain a mixture.

Example 5

Example 5 differs from example 2 only in that 100.0kg of the cleaned ABS broken material is weighed out in percentage by weight in step S2.

Comparative example 1

Comparative example 1 is different from example 2 in that step (2) does not use water-bearing steel slag friction medium, and only ABS broken wool is friction-cleaned in a high-speed friction cleaner.

Comparative example 2

Comparative example 2 differs from example 2 only in that the steel slag friction medium, which contains no water, is used to clean the plastic.

Comparative example 3

The comparative example 3 is different from the example 2 only in that the mass ratio of the ABS broken wool to the water-bearing steel slag friction medium is 1: 0.15, rotating in a high-speed friction cleaning machine at a rotating speed of 15rpm for 15 min.

Comparative example 4

Comparative example 4 differs from example 2 only in that the discharge chamber does not have a screen.

Comparative example 5

Comparative example 5 differs from example 2 only in that the water-laden steel slag friction medium has a particle size of 1 mm.

Comparative example 6

Comparative example 6 differs from example 2 only in that the ABS crushed wool and water-laden steel slag friction medium were rotated in a high speed friction washer at 1200rpm for 1 min.

Table 1 comparative example and example physical properties comparison table

The IZOD notched impact strengths of examples 1 to 5 were all 12kJ/m²The tensile strength, the elongation at break, the bending strength and the bending modulus are all superior to those of the comparative case. Meanwhile, the whiteness and the glossiness of the waste plastic material can be obviously improved by adopting the cleaning method provided by the invention according to the values of the color L, the color a and the color b and the glossiness. The water-carrying porous friction medium and the matched cleaning method can effectively remove the impurities such as glue, tinfoil, mud and the like in the waste plastics to obtain good cleaningThe effect is achieved, and meanwhile, the chemical structure of the plastic material is not changed, and the mechanical property of the plastic material is not influenced, so that the high-quality recycled plastic is obtained.

The water-carrying porous friction medium can rub with plastics to peel off impurities such as glue, tinfoil and soil on the surface of the friction medium, the carried water can effectively absorb heat generated in the friction process, the temperature of materials in the friction process is controlled, the plastic materials are prevented from being agglomerated after being softened, meanwhile, the water can further clean the plastics, and the performance of the plastic materials is not influenced by scratching the plastics. The solid-solid separator has a structure as shown in fig. 1 and 2, and comprises a spiral rotating shaft 1 and a screen cylinder 2.

Finally, it should be noted that the specific examples described herein are merely illustrative of the spirit of the invention and do not limit the embodiments of the invention. Various modifications, additions and substitutions for the embodiments described herein will occur to those skilled in the art, and all such embodiments are neither required nor possible. While the invention has been described with respect to specific embodiments, it will be appreciated that various changes and modifications may be made without departing from the spirit and scope of the invention, as defined by the appended claims.

Claims

1. The water-carrying porous friction medium is characterized by being prepared by soaking or spraying a porous hard material in water and fully absorbing water.

2. The water-carrying porous friction medium according to claim 1, wherein the porous hard material is one or more of steel slag, porous silicon carbide, hollow alumina spheres, porous titanium oxide, porous stainless steel, porous titanium and porous nickel with a particle size of 3mm or more.

3. A method for cleaning waste plastics by using water-carrying porous friction medium is characterized by comprising the following steps:

(1) placing the ABS door liner and the ABS inner container disassembled from the waste refrigerator into a crusher for crushing, and screening through a crushing chamber screen mesh and a discharging chamber screen mesh of the crusher to obtain ABS crushed wool;

(2) mixing ABS crushed wool with the water-carrying porous friction medium of claim 1, and carrying out rotary cleaning in a high-speed friction cleaning machine;

(3) screening the material obtained in the step (2) in a vibrating screen to obtain screening residues;

4. The method for cleaning waste plastic by using the water-carrying porous friction medium as claimed in claim 3, wherein in step (1), the screen mesh diameter of the crushing chamber of the crusher is 6-20 mm, the screen mesh diameter of the discharging chamber of the crusher is 1-20 mm, and a magnetic frame is placed at the discharging port of the crusher.

5. A method for cleaning waste plastics by using water-carrying porous friction medium as claimed in claim 4, characterized in that the mesh size of the crushing chamber of the crusher must be larger than that of the discharge chamber of the crusher.

6. The method for cleaning waste plastics by using the water-carrying porous friction medium as claimed in claim 3, wherein the mass ratio of the ABS broken wool to the water-carrying porous friction medium in step (2) is 1: (0.15-0.30), the rotating speed of the high-speed friction cleaning machine is 1000-1500 rpm, and the cleaning time is 3-15 min.

7. A method for cleaning waste plastics by using water-carrying porous friction medium as claimed in claim 3, wherein the mesh opening size of the screen of the vibrating screen in step (3) is between the particle size of the porous hard material and the mesh opening size of the crushing chamber of the crusher.

8. The method for cleaning waste plastic by using water-carrying porous friction medium as claimed in claim 3, wherein the solid-solid separator in step (4) is a centrifugal separator with a spiral rotating shaft and a screen cylinder, and the mesh aperture of the screen cylinder is 0-20 mm, which must be smaller than the screen aperture of the discharge chamber of the crusher.

9. The recycled ABS plastic particle material is characterized by comprising the following components in percentage by weight:

refrigerator ABS crushed material: 97.5 to 100.0 percent,

antioxidant: 0.0 to 0.5 percent,

other auxiliary agents: 0.0-2.0%;

the refrigerator ABS crushed material is obtained by cleaning waste plastic by the method for cleaning water-carrying porous friction medium as claimed in any one of claims 3-8.

10. The method for preparing a recycled ABS plastic granular material as claimed in claim 9, characterized by comprising the following steps:

s1, drying the cleaned refrigerator ABS crushed material for later use;

s2, weighing refrigerator ABS crushed materials, an antioxidant and other auxiliaries according to the weight percentage, and uniformly mixing to obtain a mixture;

and S3, putting the mixed material into a screw extruder through a feeding port for melt extrusion and granulation.