Single-screw extruder structure suitable for low-shear mixing of pearl powder and mica powder

Abstract

The utility model discloses a single screw extruder structure suitable for low shear mixing of pearl powder and mica powder, which relates to the technical field of plastic powder decoration, and comprises a feeding section, a compression section, a mixing section and a homogenizing section which are connected in sequence, a feeding port is arranged above the feeding section, the homogenizing section is connected with a discharging port, the mixing section comprises mixing blades, and the mixing blades are connected with the compression section. Grooves are formed in the tops of the mixing blades, and a plurality of flow dividing grooves are formed in the side walls of the mixing blades and used for dividing melt. The powder premixing device has the beneficial effects that the double-lead threaded blades are arranged on the feeding section, an alternate conveying area is formed, the powder premixing efficiency is improved, the follow-up mixing pressure is reduced, the gradient spiral grooves are formed in the compression section, a base body is mildly melted, local overheating is avoided, the wavy threaded blades are arranged on the mixing section, the periodic wavy grooves are formed in the tops of the blades, and the mixing efficiency is improved. And the side wall of the blade is longitudinally provided with a shunting groove, so that the flowing sectional area of the melt is periodically changed, pearl powder aggregates are dispersed, and the visual spot defect is eliminated.

Description

Technical Field

[0001] This utility model relates to the field of plastic powder decoration technology, and in particular to a single screw extruder structure suitable for low-shear mixing of pearl powder and mica powder. Background Technology

[0002] The screw of a common single-screw extruder is usually divided into three sections: feeding section, compression section and metering section. The screw has a simple thread structure, mostly with equal spacing and depth or gradually changing screw channels. It relies on the laminar shearing and compression melting of materials in the screw channels, resulting in low mixing efficiency. It is only suitable for melt extrusion of single plastics and cannot handle complex formulations. The melt temperature is uneven and the residue problem is serious.

[0003] Several commonly used screw technologies exist, such as shear-enhanced screws, which reduce unmelted particles by introducing additional threads to separate the solid and liquid phases, or by using barriers to force melt filtration and reduce impurity residue. However, these methods offer limited improvement for multi-stage dispersion. Screws integrating mixing elements include adding pin arrays to the metering section to disrupt laminar flow and create vortices, improving distributed mixing capabilities; using corrugated threads to periodically change the height of the screw ridges, enhancing local backflow; or adding a helical blade mixer at the screw end to optimize melt homogeneity. These technologies are initially suitable for blending modification, but they have poor self-cleaning capabilities and exacerbate screw wear. Screws with multi-functional modules, including multi-threaded composite structures, dynamic mixing sections, and segmented temperature control, are complex in structure, prone to deformation at high speeds, and costly. Utility Model Content

[0004] The purpose of this section is to provide a single-screw extruder structure suitable for low-shear mixing of pearlescent powder and mica powder, which can uniformly mix pearlescent powder and plastic melt to produce transparent plastic granules with a pearlescent suspension effect.

[0005] To solve the above technical problems, this utility model provides the following technical solution: a single screw extruder structure suitable for low-shear mixing of pearlescent powder and mica powder, comprising a feeding section, a compression section, a mixing section and a homogenizing section connected in sequence, wherein an inlet is provided above the feeding section, an outlet is connected to the homogenizing section, the mixing section includes mixing blades, a groove is provided on the top of the mixing blades, and a plurality of diversion grooves are provided on the sidewalls of the mixing blades, the diversion grooves being used to divert the melt.

[0006] As a preferred embodiment of the single-screw extruder structure for low-shear mixing of pearlescent powder and mica powder described in this utility model, the mixing blades are wavy in shape and used to periodically change the cross-sectional area of ​​the melt flow.

[0007] As a preferred embodiment of the single-screw extruder structure for low-shear mixing of pearlescent powder and mica powder according to the present invention, the feeding section includes large-pitch blades and small-pitch blades, which are evenly spaced apart.

[0008] As a preferred embodiment of the single-screw extruder structure for low-shear mixing of pearlescent powder and mica powder according to the present invention, the compression section includes a gradually decreasing screw channel, the depth of which gradually decreases along the movement direction of the melt.

[0009] As a preferred embodiment of the single-screw extruder structure for low-shear mixing of pearlescent powder and mica powder according to the present invention, the homogenization section includes equidistant screw channels, the depth of which is less than the minimum depth of the gradient screw channels.

[0010] As a preferred embodiment of the single-screw extruder structure for low-shear mixing of pearlescent powder and mica powder described in this utility model, the feeding section, compression section, mixing section and homogenization section are integrally formed structures.

[0011] As a preferred embodiment of the single-screw extruder structure for low-shear mixing of pearlescent powder and mica powder according to the present invention, it further includes a sleeve sleeved outside the single screw, and a drive rod is provided at one end of the sleeve near the feed inlet, and the drive rod is fixedly connected to the feed section.

[0012] The beneficial effects of this utility model are:

[0013] 1. By setting double-lead threaded blades in the feeding section to form an alternating conveying zone, the premixing efficiency of powder is improved and the subsequent mixing pressure is reduced. In the compression section, a gradual screw channel is set to gently melt the matrix and avoid local overheating. In the mixing section, a wavy threaded blade is set with a periodic wavy groove at the top of the blade and a flow-dividing groove longitudinally on the sidewall of the blade to periodically change the cross-sectional area of ​​the melt flow, disperse pearlescent powder agglomerates, and eliminate visual spot defects. The uniformity of melt distribution and mixing is improved through the segmentation-recombination mechanism, with a pearlescent powder breakage rate of <10% and a surface reflectivity retention of ≥95%.

[0014] 2. Compared to existing single-screw structures, this technical solution achieves highly uniform mixing of PVC and TPU matrices with pearlescent powder or mica powder through a wave-shaped thread-splitting groove coupled flow field, dual-lead premixing enhancement, and multi-stage precise temperature control. At the same time, it significantly reduces the damage of shear force to sheet fillers (breakage rate <10%) and improves the processing stability of high-filler systems (pressure fluctuation <5%). DLC coating and mirror polishing processes extend the equipment life to more than twice that of traditional screws, meeting the industrial production needs of high-end optical materials and environmentally friendly packaging. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the following description of the embodiments will be briefly introduced. The drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort or labor. Wherein:

[0016] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0017] Figure 2 This is a cross-sectional structural diagram of the present invention;

[0018] Figure 3 This is an enlarged schematic diagram of the mixing section of this utility model;

[0019] Figure 4 This is a front view of the single screw of this utility model.

[0020] Reference numerals: 1. Feeding section; 2. Compression section; 3. Mixing section; 4. Homogenization section; 5. Feed inlet; 6. Discharge outlet; 101. Large pitch blade; 102. Small pitch blade; 301. Mixing blade; 302. Groove; 7. Sleeve; 8. Drive rod. Detailed Implementation

[0021] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0022] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. The term "embodiment" as used herein refers to a particular feature, structure, or characteristic that may be included in at least one implementation of the present invention.

[0023] Example

[0024] Reference Figure 1 - Figure 4 This embodiment provides a single-screw extruder structure suitable for low-shear mixing of pearlescent powder and mica powder. Specifically, it includes a feeding section 1, a compression section 2, a mixing section 3, and a homogenizing section 4 connected in sequence. The feeding section 1 is provided with an inlet 5 above it, and the homogenizing section 4 is connected with an outlet 6. The mixing section 3 includes mixing blades 301. The top of the mixing blades 301 is provided with a groove 302, and the sidewall of the mixing blades 301 is provided with several diversion grooves for diverting the melt.

[0025] The feeding section 1 stably conveys powder and premixed raw materials, featuring a double-pitch thread with a pitch ratio of 1.5:1 and a groove depth of 8-12 mm. The compression section 2 gently melts the matrix, preventing localized overheating, and features a gradually changing groove and multi-stage temperature control; the groove depth gradually decreases from 12 mm to 6 mm, with external thermocouples controlling temperature in designated zones. The mixing section 3 has 1-2 mm wide distribution channels for shear-distributed mixing, protecting the pearlescent structure and creating a vortex-stretching mixing flow field. The homogenization section 4 has equidistant shallow grooves with a groove depth of 3-4 mm, providing stable extrusion pressure, eliminating flow marks, and reducing melt retention.

[0026] The mixing blade 301 is wavy in shape, used to periodically change the cross-sectional area of ​​the melt flow. The feeding section 1 includes large-pitch blades 101 and small-pitch blades 102, which are evenly spaced. The compression section 2 includes gradually decreasing spiral grooves, the depth of which gradually decreases along the direction of melt movement. The homogenization section 4 includes equidistant spiral grooves, the depth of which is less than the minimum depth of the gradually decreasing spiral grooves. The feeding section 1, compression section 2, mixing section 3, and homogenization section 4 are integrally formed. It also includes a sleeve 7 fitted outside the single screw, with a drive rod 8 located at the end of the sleeve 7 near the feed inlet 5, and the drive rod 8 is fixedly connected to the feeding section 1.

[0027] The number of flow channels is 4-6, with an inclination angle of 10-15 degrees, which can guide axial and circumferential mixing. Both compression section 2 and mixing section 3 are equipped with independent temperature control channels, through which heat transfer oil or cooling medium is introduced, ensuring that the melt temperature fluctuation is less than 3 degrees Celsius, thus avoiding thermal degradation of PVC or excessive cross-linking of TPU. The surface of mixing section 3 is coated with diamond-like carbon (DLC) to reduce the coefficient of friction and minimize the risk of pearlescent powder breakage. Homogenization section 4 adopts a mirror polishing process to eliminate the influence of flow marks on the pearlescent effect.

[0028] When in use, the raw material is poured into the feed port 5, the end of the drive rod 8 is connected to the drive mechanism, the drive mechanism is started to drive the single screw to rotate, the raw material passes through the feeding section 1, the compression section 2, the mixing section 3 and the homogenization section 4 in sequence, and finally is extruded from the discharge port 6 to form the material.

[0029] Importantly, although only a few embodiments are described in detail in this disclosure, those who consult this disclosure will readily understand that many modifications are possible without substantially departing from the subject matter described in this application, such as changes in the size, structure, shape, and proportion of various elements, as well as variations in temperature, pressure, installation arrangement, material use, color, orientation, etc.; for example, an element shown as integrally formed may be composed of multiple parts or elements, and the position of the elements may be inverted or otherwise altered; therefore, all such modifications should be included within the scope of this invention, and other substitutions, modifications, alterations, and omissions may be made in the design, operation, and arrangement of the exemplary embodiments without departing from the scope of this invention.

Claims

1. A single-screw extruder structure suitable for low-shear mixing of pearlescent powder and mica powder, characterized in that, It includes a feeding section (1), a compression section (2), a mixing section (3) and a homogenization section (4) connected in sequence. The feeding section (1) is provided with an inlet (5) above it. The homogenization section (4) is connected with an outlet (6). The mixing section (3) includes a mixing blade (301). The top of the mixing blade (301) is provided with a groove (302). The side wall of the mixing blade (301) is provided with several diversion grooves. The diversion grooves are used to divert the melt.

2. The single-screw extruder structure for low-shear mixing of pearlescent powder and mica powder as described in claim 1, characterized in that, The mixing blade (301) is wavy in shape and is used to periodically change the cross-sectional area of ​​the melt flow.

3. The single-screw extruder structure for low-shear mixing of pearlescent powder and mica powder as described in claim 1, characterized in that, The feeding section (1) includes a large-pitch blade (101) and a small-pitch blade (102), which are evenly spaced apart.

4. The single-screw extruder structure for low-shear mixing of pearlescent powder and mica powder as described in claim 1, characterized in that, The compression section (2) includes a tapered spiral groove, the depth of which gradually decreases along the direction of movement of the melt.

5. The single-screw extruder structure for low-shear mixing of pearlescent powder and mica powder as described in claim 1, characterized in that, The homogenization section (4) includes equidistant spiral grooves, the depth of which is less than the minimum depth of the gradient spiral grooves.

6. The single-screw extruder structure for low-shear mixing of pearlescent powder and mica powder as described in claim 1, characterized in that, The feeding section (1), compression section (2), mixing section (3) and homogenization section (4) are integrally formed structures.

7. The single-screw extruder structure for low-shear mixing of pearlescent powder and mica powder as described in claim 1, characterized in that, It also includes a sleeve (7) sleeved outside the single screw, and a drive rod (8) is provided at one end of the sleeve (7) near the feed port (5), and the drive rod (8) is fixedly connected to the feed section (1).

Images