CN113334610A

CN113334610A - High-rotation-speed high-shear two-stage extrusion granulation process

Info

Publication number: CN113334610A
Application number: CN202110757102.8A
Authority: CN
Inventors: ***; 莫鹏翔
Original assignee: Anhui Hongze New Material Technology Co ltd
Current assignee: Anhui Hongze New Material Technology Co ltd
Priority date: 2021-07-05
Filing date: 2021-07-05
Publication date: 2021-09-03

Abstract

The invention discloses a high-rotation-speed high-shear two-stage extrusion granulation process, relates to the technical field of chemical industry, and solves the problem of low qualified rate of granules. The following scheme is now proposed: comprises the following preparation steps; s1: waste plastic treatment: cleaning the recycled plastic through a high-pressure spray head, removing impurities on the surface, drying the plastic through first quality inspection after the plastic passes through first quality inspection, and ensuring complete drying without residual moisture on the surface; s2: preparing a premix: crushing the plastic, banburying the crushed plastic in a banbury mixer, adding an accelerator, a coupling agent and a modifier, and mixing and banburying the mixture to obtain a premix; s3: removing impurities: and filtering the premix through a filter screen to further remove the residual impurities in the premix. The invention has the advantages of maintaining the continuity of production, completely removing the remaining small impurities, completely removing bubbles in the material and maintaining the granulation qualification rate.

Description

High-rotation-speed high-shear two-stage extrusion granulation process

Technical Field

The invention relates to the technical field of chemical industry, in particular to a high-rotation-speed high-shear two-stage extrusion granulation process.

Background

In the peak period of scrapping of domestic waste household appliances, plastics are important components of the waste household appliances, the weight ratio of the plastics is up to 30-40%, and the weight ratio exceeds the yield of metal materials in terms of yield and volume. Therefore, the recycling of waste plastics becomes a concern in the household appliance recycling industry, and the plastics in the waste household appliances are mainly recycled by recycling granulation at present.

Plastics are high molecular compounds (macromolecules) which are polymerized by addition polymerization or polycondensation reaction and are intermediate in deformation resistance between fibers and rubber, and are composed of synthetic resin, fillers, plasticizers, stabilizers, lubricants, pigments and other additives.

The main component of the plastic is resin. The resin means a polymer compound which has not been mixed with various additives. The term resin is originally named as lipids secreted by animals and plants, such as rosin, shellac, and the like. The resin accounts for about 40-100% of the total weight of the plastic. The basic properties of plastics are largely determined by the nature of the resin, but additives also play an important role. Some plastics consist essentially of synthetic resins, with no or little additives, such as plexiglas, polystyrene, etc.

At present, the existing waste plastics generally have the following defects in the manufacturing and processing process: 1. when the existing equipment is used for crushing and processing waste plastics, a lot of impurities exist in the crushed plastics, and the crushed plastics still exist after being cleaned by clear water, so that the subsequent processing effect of the waste plastics is poor, and the subsequent use is not facilitated

At present, the twin-screw extruder is widely applied to the fields of plastics and rubber, and particularly, the co-rotating parallel twin-screw extruder has excellent mixing effect and high processing efficiency and is the most effective means for processing modified plastics. The double-screw extruder can add solid raw materials such as polymer granules or flakes and the like into the screw part through the feed inlet, and plasticize the polymer materials into a molten state for later use through the comprehensive actions such as heating, extrusion force of the screw and the like. The twin-screw extruder has better mixing, exhausting and self-cleaning functions than a single-screw extruder, so that the twin-screw extruder is widely applied and paid attention to.

For a long time, the high torque, high rotation speed and high yield which are main performance indexes of extrusion molding equipment are always the main development directions of the extrusion molding machine, and especially the rapid development of polymer nano composite materials puts higher requirements on the extrusion molding equipment. However, in the process of granulation, the temperature of the traditional extruder screw can be lost, which results in poor granulation effect.

Therefore, how to solve the problem of impurities in the recycled plastics is a technical problem which needs to be solved by the technical personnel in the field at present.

Disclosure of Invention

Objects of the invention

In view of the above, the present invention provides a high-speed high-shear two-stage extrusion granulation process to achieve a higher yield of the prepared granules.

(II) technical scheme

In order to achieve the technical purpose, the invention provides a high-speed high-shear two-stage extrusion granulation process, which comprises the following preparation steps;

s1: waste plastic treatment: cleaning the recycled plastic through a high-pressure spray head, removing impurities on the surface, drying the plastic through first quality inspection after the plastic passes through first quality inspection, and ensuring complete drying without residual moisture on the surface;

s2: preparing a premix: crushing the plastic, banburying the crushed plastic in a banbury mixer, adding an accelerator, a coupling agent and a modifier, and mixing and banburying the mixture to obtain a premix;

s3: removing impurities: filtering the premix through a filter screen, and further removing impurities remained in the premix;

s4: primary extrusion forming: pouring the impurity-removed premix into a double-screw extruder, gradually compacting the material by gradually reducing the screw pitch in the double-screw extruder, and simultaneously extruding gas generated during banburying to form a primary sheet material;

s5: and (5) stably forming again: feeding the primary flaky material formed in the step S4 into a second-stage double-screw extruder, and then compacting again to completely extrude bubbles in the material;

s6: granulation: and (3) starting a roller extrusion granulator to crush and granulate the compacted plate, and then pouring the granules into a screening machine for screening, wherein the granules meeting the requirements are finished granules.

Preferably, the drying temperature in S1 is 50 ℃ and the drying time is 20 minutes. .

Preferably, the banburying temperature in S2 is 150 ℃ and 200 ℃, and the time is 1-1.5 h. .

Preferably, the promoter in S2 is one or more of aluminum fluoride chloride, aluminum trichloride and boron trifluoride.

Preferably, a heat preservation system is arranged in the second-stage double-screw extruder.

Preferably, the twin-screw extruder is a twin-stage twin screw.

Preferably, the double screws are cylindrical and detachable, and different modules such as kneading discs, thread blocks and the like can be correspondingly installed according to the shearing requirements.

Preferably, the filter net in S3 needs to be replaced periodically.

Preferably, the coupling agent is one or more of vinyltrichlorosilane, vinyltrimethoxysilane and gamma-chloropropyltrimethoxysilane respectively.

Preferably, the modifier is polysulfide rubber.

(As can be seen from the technical scheme, the application has the following beneficial effects.)

(1): according to the invention, the waste plastic is cleaned under high pressure before being crushed, and then is filtered through the filter screen after banburying mixing, so that the remaining small impurities can be completely removed, and the filter screen is periodically replaced, so that the production continuity can be maintained, the drying temperature is controlled, and the bonding caused by overhigh temperature is prevented from influencing the effect of post-production;

(2): according to the invention, the materials are extruded twice through the double-screw extruder with two stages, the extruded flaky materials are thicker, air bubbles in the materials can be completely removed, and the granulation qualification rate is kept;

(3): the heat preservation system is arranged in the second-order double-screw extruder, so that the temperature of the material is not reduced in the extrusion process, the heat is not lost, and the material is conveniently cut and granulated in the later stage.

Drawings

FIG. 1 is a flow chart of steps provided by an embodiment of the present invention;

Detailed Description

The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, identical or similar reference numerals indicate identical or similar parts and features. The drawings are only schematic representations of the concepts and principles of the embodiments of the disclosure, and do not necessarily show specific dimensions or proportions of the various embodiments of the disclosure. Certain features that are part of a particular figure may be exaggerated in order to illustrate relevant details or structures of embodiments of the present disclosure.

As shown in fig. 1, a flow chart of steps provided by an embodiment of the present invention includes the following preparation steps;

s1: waste plastic treatment: the recycled plastic is cleaned through a high-pressure sprayer, impurities on the surface of the recycled plastic are removed, and after the recycled plastic passes through the first quality inspection, the recycled plastic is dried through the first quality inspection, so that complete drying is ensured, and no water is left on the surface (the problem that adhesion is caused by overhigh temperature and the effect of post-production is influenced) is solved;

s6: granulation: open the granulation is smashed to the panel after the roller extrusion granulator will densify, then screen in pouring the sieve separator with the granule, the granule that meets the requirements is very finished product granule, carry out high-pressure cleaning before the crushing to old and useless plastics, then filter through the filter screen after the banburying mixes, can get rid of the little impurity that gets off completely, and the filter screen is regularly changed, can keep the continuity of production, twice extrude the material, the slice material that extrudes is more solid, and can get rid of the bubble in the material completely, keep the qualification rate of granulation.

A high speed, high shear, two-stage extrusion granulation process according to an exemplary embodiment of the present invention may achieve higher resulting pellet yields. Specifically, when the device is used, recycled plastics are cleaned through a high-pressure spray head, impurities on the surface of the recycled plastics are removed, after the recycled plastics pass through a first quality inspection, the recycled plastics pass through the first quality inspection and are dried to ensure complete drying, no water is left on the surface (the situation that the adhesion is caused by overhigh temperature and the effect of post-production is influenced) and are crushed and placed into an internal mixer for internal mixing, an accelerant, a coupling agent and a modifier are added for mixing and internal mixing to obtain a premix, the premix is filtered through a filter screen, the impurities left in the premix are further removed, the premix with the impurities removed is poured into the double-screw extruder, the screw pitch in the double-screw extruder is gradually reduced, the materials are gradually compacted, and meanwhile, gas generated during the internal mixing is extruded to form a primary sheet-shaped material; feeding the primary flaky material into a second-stage double-screw extruder, and then compacting again to completely extrude bubbles in the material; and (3) starting a roller extrusion granulator to crush and granulate the compacted plate, and then pouring the granules into a screening machine for screening, wherein the granules meeting the requirements are finished granules.

Exemplary embodiments of the proposed solution of the present disclosure have been described in detail above with reference to preferred embodiments, however, it will be understood by those skilled in the art that many variations and modifications may be made to the specific embodiments described above, and that many combinations of the various technical features and structures presented in the present disclosure may be made without departing from the concept of the present disclosure, without departing from the scope of the present disclosure, which is defined by the appended claims.

Claims

1. A high-speed high-shear two-stage extrusion granulation process is characterized by comprising the following preparation steps;

2. The high-speed high-shear two-stage extrusion granulation process according to claim 1, wherein the drying temperature in S1 is 50 ℃ and the drying time is 20 minutes.

3. The process according to claim 1, wherein the mixing temperature in S2 is 150 ℃ and 200 ℃ and the mixing time is 1-1.5 h.

4. A high-speed high-shear two-stage extrusion granulation process according to claim 1, wherein the accelerator in S2 is one or more of aluminum chloride fluoride, aluminum trichloride and boron trifluoride.

5. A high-speed high-shear two-stage extrusion granulation process as claimed in claim 1, wherein a heat preservation system is arranged in the second-stage twin-screw extruder.

6. A high speed high shear two stage extrusion granulation process as claimed in claim 1, wherein said twin screw extruder is a two stage twin screw.

7. A high-speed high-shear two-stage extrusion granulation process as claimed in claim 6, wherein the twin-screw is cylindrical and detachable, and different modules such as kneading discs and threaded blocks can be installed correspondingly according to the shearing requirements.

8. A high speed high shear twin stage extrusion granulation process as claimed in claim 1, wherein the filter screen in S3 needs to be replaced periodically.

9. A high speed high shear dual stage extrusion granulation process as claimed in claim 1, wherein the coupling agent is one or more of vinyltrichlorosilane, vinyltrimethoxysilane and gamma-chloropropyltrimethoxysilane, respectively.

10. A high speed high shear two stage extrusion granulation process as claimed in claim 1, wherein said modifier is polysulfide rubber.