CN101204837A - Regeneration granulation process for waste high-foaming plastic - Google Patents

Abstract

The invention relates to the technical field of recycling granulation process of high molecular polymer, in particular to a recycling granulation process of waste high foam plastics. The process comprises impurity removal, manual feeding, automatic crushing, automatic forced feeding, feeding with a large screw and a large screw groove, first-stage compression and exhaust with a large screw with a variable pitch, second-stage heating and compression with a variable screw diameter, third-stage compression with a variable screw bottom diameter for heating and melting, removal of water vapor and residual gas, fourth-stage compression of the melt, non-stop net replacement and filtration, strip extrusion, cooling and shaping, pelletizing, and manual metering and packaging into bags. The process is simple to operate, low in energy consumption, high in production efficiency, low in production cost, strong in practicality, has great market potential, is convenient for large-scale and specialized production, can significantly improve the labor production environment and operation safety, form a recycling market, and promote environmental protection.

Description

Recycling and granulation process of waste high foaming plastic

technical field

The invention relates to the technical field of high-molecular polymer recycling technology, in particular to the regeneration and granulation technology of waste high-foaming plastics.

Background technique

Plastic products are indispensable products in people's daily life, such as plastic bags, EPE foam products, beverage bottles, mobile phone casings, etc., which are widely used and used in huge quantities. In order to meet the needs of daily necessities and industrial products, the output of plastic products It is also increasing day by day, and discarded plastic products are difficult to degrade, and are discarded in every corner of life, polluting the environment, which is called "white pollution". At first, in order to solve this problem, people used incineration to solve this problem, and burned waste plastics, but the burning of plastics produced a large amount of dioxin (Dioxin), causing secondary pollution. Since then, in order to avoid secondary pollution, people have adopted landfill methods. Landfill waste plastics, but it takes hundreds of years for ordinary waste plastics to decompose and disappear, and the effect is not good.

Later, people adopted the method of recycling and recycling, which not only achieved the effect of environmental protection, but also saved resources for my country, which is short of energy. For thermoplastic waste plastics such as micro-foamed or non-foamed polyethylene, polypropylene, polystyrene, etc., the recycling and granulation process is as follows:

(1) Collection and classification of waste plastics;

(2) Crusher crushing and cleaning;

(3) Ordinary recycled granulator completes the following steps:

Manually feed the pulverized material through step (2) from the hopper of the ordinary regeneration granulator, and the crushed material is heated, melted and compressed by the screw of the ordinary regeneration granulator to form a molten material, and the molten material is discharged through the exhaust port of the regeneration granulator. Residual gases such as steam are compressed again in a molten state, and then extruded from the die in strips after being filtered through the screen of an ordinary regeneration granulator;

(4) After being cooled and cut into plastic granules; manually measured and packed into bags.

For high-foaming plastic waste, its 20-40 times high-magnification foaming, its recycling and granulation process is as follows:

(1) Waste collection and classification;

(2) After being pulverized by the crusher, it becomes small cotton-like particles;

(3) The regeneration granulator completes the following steps:

The pulverized material in step (2) is forced-fed through the screw agitation of the hopper of the regenerating granulator, and the pulverized material is heated to 200°C to 300°C in the screw of the regenerating granulator to melt and compress at low power. Exhaust the residual gas from the exhaust port, re-melt the screw and compress it at low power, pass through the 60-80 mesh double-layer global filter of the regeneration granulator, and then extrude from the die head in strips;

(4) After being cooled and cut into plastic granules; manually measured and packed into bags.

EPE high-foaming plastic is made of low-density polyethylene LDPE as raw material, talc powder as auxiliary material, injecting monoglyceride stearate additive in hot state, and injecting high-pressure butane as foaming agent in molten state, at 170 ° C ~ 200 ° C Extruded under high pressure to form a loose, foamed plastic product with a certain compression elasticity, forming a foamed product with a volume expansion of 20 to 40 times, generally about 25 times.

According to the characteristics of high foaming plastics, the above granulation has the following problems:

(1) The labor intensity is high. After the high-foaming waste is crushed, the volume will further increase. After crushing, it needs to be manually transported to the hopper of the granulation equipment. Due to the large volume and low density, the transport efficiency is low, the transport frequency is high, and the labor intensity is high.

(2) Air pollution, poor working environment, high foaming. During the crushing process and the screw forced feeding of the granulator, a large amount of cotton-like dust is produced, which floats in the air and is difficult to disappear. It pollutes the air environment and is a serious threat to the health of production workers. , easy to form incurable occupational diseases.

(3) The feed port of the granulator must be screwed in, or manually squeezed with a wooden stick, before feeding, otherwise, the high-foaming fragments with low density will form an "arch bridge" feeding failure, which cannot be continued Feeding materials, there is a major safety hazard, and industrial accidents are prone to occur.

(4) The diameter of the screw of the granulator is φ110～φ150, and the compression ratio is not more than 10 times, which is far less than 25 times that of EPE high-foaming products. In order to maintain continuous production, only by reducing the number of discharge holes of the granulator die can the screw be maintained. The pressure of the molten plastic inside forms a continuous strip discharge.

(5) Due to the small number of discharge holes in the die head of the granulator and insufficient feeding, the molten plastic stays in the screw for too long, and the plastic in the screw groove is repeatedly sheared and stirred by the screw in a high-temperature molten state, which is easy to cause plastic decomposition. , discoloration, denaturation, easy to form pores, non-dense granules, the product is difficult to meet the requirements for reuse.

(6) Energy consumption is high, efficiency is low, and production cost is high. Even with a large screw of φ150, the output per hour can reach more than 200 kg when producing EPE waste plastic bag granulation, but when used for EPE high-foaming plastic granulation, it is difficult to feed loose waste materials and the screw inlet is difficult to enter. A large number of vacant screw melt tanks have a small amount of extrusion, and the output per hour is less than 60 kg. If the φ120 screw is used, the output is lower and basically has no market value. Due to the high production cost and no advantage in price compared with new raw materials, it is difficult to Create a recycling market.

Contents of the invention

The purpose of the present invention is to provide a high-foaming waste plastic regeneration granulation process with simple operation, high output, large-scale production and market value, aiming at the shortcomings of the prior art of EPE high-foaming plastic waste.

In order to achieve this purpose, the present invention is realized through the following scheme, high-foaming waste plastic recycling granulation process:

The recycling granulation process of waste high-foaming plastics comprises the following steps,

(1) Recycling, collection of highly foamed plastic waste;

(2) Remove impurities, remove other plastic attachments and large impurities from high foaming plastic waste;

(3) The waste high foaming plastic recycling granulator completes the following steps:

(A) For the recycled high-foaming plastic waste, put it directly into the hopper of the waste high-foaming plastic regeneration granulator, the crushing device will crush the high-foaming plastic, and crush the high-foaming plastic under the pressure of the square crushing shear blade and the square static knife of the crushing device. Down, forcefully press into the space of the screw groove of the large screw;

(B) The high-foaming plastics entering the screw channel are compressed in turn by variable pitch of the screw (first-stage compression) and variable-diameter compression (second-stage compression) in the waste high-foaming plastic regeneration granulator, and the looseness is removed through the vent hole. A large amount of gas in plastic, melt compression (third stage compression);

(C) After three-stage compression, the molten high-foaming plastic reaches the groove of the deepening screw. The screw groove is equipped with pins for stirring, and the pressure of the molten high-foaming plastic suddenly drops. At this time, the temperature of the molten plastic is above 150°C, and water vapor and residual gas The released overflow is discharged from the exhaust hole of the waste high foaming plastic recycling granulator;

(D) After the exhaust, the molten plastic is compressed again (the fourth compression), and is filtered through a second layer of 60-80 mesh stainless steel mesh to form a melt glue, and remove small particles of impurities remaining in the melt glue;

(E) The molten glue after filtering has bigger viscosity, continuously extrudes from 37 φ 3 small holes of the die into strips;

(4) After water cooling and shaping, the granulator cuts into small particles with a length of 2 to 6 mm, weighs them manually, and packs them into bags.

The width of the feed inlet is 250-350 mm, and the length is 450-500 mm.

The crushing device is a square shearing blade and a square static knife driven by a power mechanism. The crusher is equipped with a moving square shearing blade and a square static blade, and the moving square shearing blade rotates. When rotating, it interlaces with the static blade to complete the shearing of high-foaming plastics, and achieves the function of forced feeding under the pressure of the plane of the moving square shear blade. The forced feeding pressure can reach 50-100kg force.

The crushing pressure in the step (A) of the step (3) is 8,000-10,000 Kg/cm ² , the forced feeding pressure can reach 50-100 kg/cm ² , and the diameter of the feeding screw is φ240cm.

In the step (B) of the step (3), the screw pitch is reduced from 180cm to 95cm to complete the first stage of compression, and then the outer diameter of the screw is reduced to φ120cm to complete the second stage and the third stage of compression.

The high-foaming plastic melted in step (C) in the step (3) reaches the groove of the deepening screw, and the depth of the groove is 70 mm.

The high-expanded polyethylene (abbreviated as EPE), high-expanded polypropylene (abbreviated as EPP), and high-expanded polystyrene (abbreviated as EPS).

The beneficial effect of technique of the present invention:

(1) This process is produced by a machine integrating crushing and granulation, which can be operated by one person, with low labor costs, continuous and closed operation of crushing and feeding, no flocculent dust, and a good production environment.

(2) Three-stage compression of feeding material melting, the total compression amount is 45 times, which is far greater than the expansion ratio of 25 times of EPE waste, easy feeding, uniform pressure of the production screw, high production efficiency, and the output per hour can reach 200-250kg

(3) The crushing device is a square shear knife and a square static knife. The thickness of the square blade is 20mm. Under the low speed and high torque of 30r/min, the EPE foaming waste is crushed into pieces with a width of less than 25mm. Under the forced pressure of the moving blade plane, it is very easy to fill the screw groove with a depth of 70mm and a lead of 180mm, and has a primary supplementary compression function to ensure that the EPE waste continuously fills the screw groove to form compression, ensuring continuity and high extrusion. Yield

(4) The screw adopts four-stage compression such as large variable diameter and large variable pitch. The compression volume of the first three stages is 45 times, which is far greater than the foaming rate of 25 times that of EPE high waste, and the combination of heating, melting and compression is carried out, and the production efficiency is high. Low energy consumption, low labor cost, low labor intensity, great market potential and practicability, and facilitate the realization of specialized and large-scale production.

(5) It has the market potential of industrialization, and it is easy to form a recycling market, which is conducive to environmental protection and resource reuse. The crushing and feeding are closed, and the production environment is greatly improved, which is conducive to protecting the health of industrial workers, factory environment and operation safety. .

Description of drawings

Accompanying drawing 1 is process flow chart of the present invention

Detailed ways

Example 1

Below in conjunction with accompanying drawing, the present invention is further described, see shown in accompanying drawing 1, waste foamed plastic regeneration granulation process, comprises the following steps:

(1) Discarded EEP high foaming plastics;

(2) Impurity removal, removing other impurities from the recycled waste EPE high foaming plastic;

(3) The waste high foaming plastic recycling granulator completes the following functions:

(A) Crushing and feeding, transfer the waste EPE foamed plastics through step (2) into the hopper of the waste high foaming plastic regeneration granulator, and use the crushing device in the waste high foaming plastic regeneration granulator hopper to crush the waste EPE The high-foaming plastic is crushed into blocks. The crushing device is a combination of a square shear knife and a square static knife. The thickness of the square shear knife is 20mm. The waste foamed plastic polyethylene is broken into larger fragments with a width of 25-35mm, and is strongly pressed into the φ240 screw groove under the pressure of the blade at a pressure of 50-100kg/ ^cm2 ;

(B) EPE high-foaming fragments are compressed by the first stage of the screw, that is, the variable pitch compression of the large screw, the pitch of the large screw changes from 180 to 95, the width of the screw groove changes from 160 to 80, the bottom diameter remains unchanged, and the compression amount is 2 times. It is non-melting compression, which can eliminate the loose gas in part of the waste; heating and compression, the outer diameter of the screw changes from φ240 to φ120, variable diameter compression, the pitch remains unchanged, the bottom diameter of the screw remains unchanged, and the compression amount is 5.5 times, which is the second largest. Stage compression, heating and melting, a large amount of residual gas in the loose body of EPE foam is discharged, and discharged from the material inlet through the gap between the barrel wall, the heating temperature is 160 ° C ~ 220 ° C; the solid and viscous melt mixture enters the third stage compression section, heating and melting at the same time, the heating temperature is 180 ° C ~ 240 ° C, the outer diameter of the screw is φ120 unchanged, the bottom diameter gradually increases, and the compression amount is 4.2 times. The solid in this section is completely melted into a viscous shape, and there is residual gas inside , the water in the waste has been safely turned into water vapor, which is extruded into the exhaust section under high pressure, and the total compression of the first, second and third stages is 45 times;

(C) In the degassing section, the depth of the screw groove suddenly deepens by 2 times, the pressure of the high-pressure viscous melt suddenly drops, and under the action of pin stirring, the water vapor and residual gas in the melt are discharged from the vent hole with an area of 50×180.

(D) After the viscous melt has exhausted the residual gas and water vapor, it enters the fourth stage of compression, which is also a dense compression section. The outer diameter and pitch of the screw remain unchanged, the bottom diameter gradually increases, and the compression amount is 4 times. The melt is compressed Mixing evenly, enter the filter device and discharge die head under pressure, filter mechanism, change the screen in an electric way without stopping, and filter the residual particulate impurities in the melt with a double-layer 80-mesh stainless steel screen;

(E) Extrude through 37 φ small holes of the die head, and the small holes of the die head are continuously discharged to form 37 circular sticky rubber strips,

(4) After immersing in water for rapid cooling, the granulator cuts off granules with a length of 2-6 mm, weighs them manually, and packs them into granulated plastic raw materials.

Granular plastic products can be used again in EPE foaming machines as raw materials to produce EPE foam packaging materials, which are widely used in furniture, hardware, electronics, electrical packaging, and can also be used for lining of bags, shoes, sofas, etc., and air-conditioning pipes Thermal insulation and other packaging purposes.

Claims (7)

1. discarded high foaming plastics regeneration pelleting process is characterized in that: may further comprise the steps,

(1) reclaim, high foaming plastic refuse is collected;

(2) removal of impurities is removed other plastics adjunct and bulk impurity with the height plastic refuse that foams;

(3) discarded foaming plastics regeneration comminutor occurred frequently is finished following steps:

(A) for the height foaming plastic refuse that reclaims, directly put into discarded foaming plastics regeneration comminutor hopper occurred frequently, breaker smashes high foamed plastic, and under the pressure of the square broken shear-blade of breaker and square quiet cutter, forces to be pressed in the screw channel space of big screw rod;

(B) the high foamed plastic that enters in the screw channel compresses (first order compression) through the screw rod displacement successively in discarded foaming plastics regeneration comminutor occurred frequently, reducing compression (second level compression), a large amount of gases in the loose plastics of steam vent eliminating, fusion compression (third level compression);

(C) after three grades of compressions, the high foamed plastic of fusion arrives deepens screw channel, screw channel disposes pin and stirs, the high foaming of fusion plastic pressure descends suddenly, this moment, the molten plastic temperature was more than 150 ℃, and water vapour and survival gas are released to overflow by foaming plastics regeneration comminutor steam vent discarded occurred frequently and discharge;

(D) molten plastic compresses (the 4th compression) once more after the exhaust, filters through two layer of 60～80 order stainless (steel) wire and forms melten gel, removes the granule impurity of melten gel remnants;

(E) melten gel after the filtration has bigger viscosity, extrudes continuously into strips from 37 φ 3 apertures of die head continuously;

(4) cut into the long granule of 2～6mm through water cooling setting, pelleter, the manual weighing is packaged into bag.

2. discarded high foaming plastics regeneration pelleting process according to claim 1 is characterized in that: described feeding mouth width is 250～350mm, length 450～500mm.

3. discarded high foaming plastics regeneration pelleting process according to claim 1 is characterized in that: described breaker is square shear-blade and the square quiet cutter that actuating unit drives.

4. discarded high foaming plastics regeneration pelleting process according to claim 1 is characterized in that: the pressure that smashes of (A) step is 8,000～10,000 Kg/cm in the described step (3) ², force feed pressure can reach 50～100kg/cm ², the pan feeding screw diameter is φ 240cm.

5. discarded high foaming plastics regeneration pelleting process according to claim 1, it is characterized in that: (B) step pitch is reduced to 95cm from 180cm in the described step (3), finish first order compression, the screw rod external diameter is decreased to φ 120cm then, finishes the second level, third level compression.

6. discarded high foaming plastics regeneration pelleting process according to claim 1 is characterized in that: the high foamed plastic of (C) step fusion arrives and deepens screw channel in the described step (3), and spiral groove depth is 70mm.

7. discarded high foaming plastics regeneration pelleting process according to claim 1 is characterized in that: described high foamed plastic is a highly foaming polyethylene, high expanded polypropylene, highly foamed polystyrene.