A preparation process of environmentally friendly EVA foam injection particles

Abstract

The invention discloses a preparation process of an environmentally friendly EVA foam injection granule, and relates to the field related to the production of injection granules. The invention effectively improves the mixing uniformity by introducing a staged mixing technology in the process: by adding and mixing each component in stages and batches, each component is ensured to be evenly distributed to avoid excessive or low local concentration; reduces the risk of degradation: in the mixing process, the mixing is carried out in sections to reduce the risk of degradation of the foaming agent and the cross-linking agent by high temperature for a long time, and maintains the stability of the material; optimizes the production efficiency: the staged mixing can better control the mixing process, reduce downtime, and improve production efficiency.

Description

Technical Field

[0001] The invention relates to the field related to the production of injection rubber particles, and in particular to a preparation process of environmentally friendly EVA foaming injection rubber particles. Background Art

[0002] Environmentally friendly EVA foam injection granules refer to ethylene-vinyl acetate copolymer (EVA) foam materials prepared through environmentally friendly processes. This material is based on renewable, degradable or environmentally friendly raw materials, ensuring that no harmful substances are released during production and use, which is harmless to the human body and environmentally friendly. In addition, discarded EVA foam materials can be recycled and reused, reducing resource waste and environmental pollution, while focusing on reducing carbon emissions throughout the entire production chain, thereby achieving more sustainable development.

[0003] Chinese Patent: CN201821092902.2, an EVA colloid production equipment, characterized in that: the EVA colloid production equipment includes a melt pump, a grinder, a dehydrator, a circulating water chiller and a vibrating screen, the melt pump is connected to three reactors through three pipelines respectively, an automatic pressure regulating device is provided between the melt pump and the grinder, the grinder and the dehydrator are connected through a U-shaped pipeline, the dehydrator and the circulating water chiller are connected through a Z-shaped pipeline, a water tank is arranged at the bottom of the dehydrator, and a controller is provided on the U-shaped pipeline; the three pipelines are threadedly connected to the flange, the flange is bolted to the melt pump, the grinder is connected to the U-shaped pipeline through a flange, and the Z-shaped pipeline is screwed to the water tank of the dehydrator through a pipe joint. The EVA colloid production equipment described in the patent realizes automatic control of particle size and improves production efficiency.

[0004] The above patents and prior art have the following problems in actual use: most of the processing is carried out continuously during the production process, resulting in excessively high or low local concentrations during material mixing, and there is a risk of degradation of the foaming agent and the cross-linking agent due to high temperature and long time during the mixing process; and in the screening process, a small-amplitude vibration screening method is used, which is inefficient and consumes too much energy. Summary of the invention

[0005] Therefore, in order to solve the above-mentioned shortcomings, the present invention provides a preparation process of an environmentally friendly EVA foam injection granule.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme: a preparation process of environmentally friendly EVA foam injection particles, the specific steps are as follows:

[0007] S1 Raw material preparation: EVA resin: vinyl acetate content is 10%-40%; foaming agent: azodicarbonamide; cross-linking agent: di-tert-butyl peroxide; other additives: antioxidant 1010, lubricant zinc stearate, masterbatch;

[0008] S2 Preliminary mixing: High-speed mixer: Pour EVA resin, antioxidant and masterbatch into a high-speed mixer for preliminary mixing at a speed of 500-1000 rpm for 2-3 minutes;

[0009] S3 Adding blowing agent and cross-linking agent: Gradually adding: After the initial mixing is completed, gradually add blowing agent and cross-linking agent, and continue mixing in the high-speed mixer at a speed of 500-800 rpm for 2-3 minutes;

[0010] S4 Internal Mixing: Put the mixed materials into the internal mixer at a temperature of 90-110°C for 5-10 minutes, and then perform segmented internal mixing. Put the mixed materials into the internal mixer in two or three stages, and each stage of internal mixing lasts for 2-3 minutes.

[0011] S5 extrusion granulation: the mixed material is extruded into strips through an extruder at a temperature of 80-100°C, and the cooled strips are cut into pellets through a pelletizer;

[0012] S6 Cooling and shaping: Cool the freshly extruded particles by water cooling to avoid particle adhesion, and use shaping equipment to ensure the stability of particle shape;

[0013] S7 colloid particle screening: the shaped colloid particles are screened by automatic screening equipment;

[0014] S8 Quality Inspection: Density, hardness and elasticity inspection are carried out on the rubber particles of qualified size after screening.

[0015] Preferably, the automated screening equipment includes a stage swing screening device, an adjusting device arranged at both ends of the bottom of the stage swing screening device, a supporting and collecting box connected to the bottom of the adjusting device, and an opening and closing cover arranged on the left and right sides of the supporting and collecting box. A first motor is arranged in the middle of the front end of the adjusting device for driving, and an opening is opened in the middle of the supporting and collecting box.

[0016] Preferably, the stage swing screening device includes two sets of relatively arranged swing mechanisms, a fixed plate arranged inside the two sets of swing mechanisms and a screen arranged inside the fixed plate, and a set of adjustment devices is correspondingly connected to the bottom of the swing mechanism.

[0017] Preferably, the swing mechanism includes a support for support, a transmission box arranged at the top of the support, a second motor arranged at the top of the transmission box, a connecting shaft arranged at the right end inside the transmission box, a support block arranged at the bottom of the transmission box and penetrated by the connecting shaft, a toggle member connected to the bottom of the connecting shaft, a contact rod penetrating the other end of the toggle member, a supporting guide member abutting against the bottom of the contact rod and fixedly arranged on the top of the support, a linkage member arranged at the lower end of the contact rod, a first side rod connected to the other end of the linkage member, a first connecting rod hinged at both ends of the first side rod, a second side rod hinged at the other end of the first connecting rod, a second connecting rod hinged to the other end of the second side rod, a third side rod hinged at the other end of the second connecting rod, a third connecting rod hinged to the other end of the third side rod, and a base hinged to the other end of the third connecting rod, the bottom of the base is fixedly arranged on the top of the support, the bottom of the support is connected to the adjusting device, and three sets of fixing plates are respectively connected to the middle of the inner sides of the first side rod, the second side rod and the third side rod.

[0018] Preferably, the supporting guide is semi-cylindrical.

[0019] Preferably, the linkage member is L-shaped.

[0020] Preferably, a driving pulley connected to the output shaft of the second motor is provided in the middle of the transmission box, the outer side of the driving pulley rotates synchronously with the driven pulley through a synchronous belt, and the middle of the driven pulley is connected to a connecting shaft.

[0021] Preferably, the adjusting device includes a bottom box arranged on the top of the supporting collection box, a screw rod arranged in the middle of the bottom box and connected to the output shaft of the first motor, a sliding member threadedly connected to the middle of the screw rod, a sliding box connected to the top of the sliding member, cylinders arranged at both ends of the sliding box, a support member hinged to the ejection rod at the top of the cylinder, and an ear arranged at the bottom of the support member and hingedly connected to the inside of the sliding box.

[0022] Preferably, a guide groove is provided in the middle of the top end of the bottom box, and the guide groove is penetrated by a sliding member.

[0023] Preferably, the bottom of the support is arc-shaped.

[0024] Beneficial effects of the present invention:

[0025] The present invention effectively improves mixing uniformity by introducing staged mixing technology in the process: by adding and mixing the components in stages and batches, each component is ensured to be evenly distributed to avoid excessively high or low local concentrations; the risk of degradation is reduced: the mixing is carried out in sections during the mixing process to reduce the risk of degradation of the foaming agent and the cross-linking agent by high temperature for a long time and maintain the stability of the material; the production efficiency is optimized: the mixing in stages can better control the mixing process, reduce downtime and improve production efficiency.

[0026] The present invention is completed by utilizing automated screening equipment in the particle screening step. The automated screening equipment is equipped with a stage swing screening device. The stage swing screening device is equipped with three groups of screens. The swinging is controlled by a swing mechanism. The three groups of screens have asynchronous swinging directions, thereby effectively realizing stage screening. In combination with an adjusting device, the position and angle of the screens can be adjusted, thereby facilitating stable material guiding, reducing manual operations, and improving work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the automated screening equipment of the present invention;

[0028] Figure 2 It is a schematic diagram of the structure of the swing screening device of the present invention;

[0029] Figure 3 It is a schematic diagram of the structure of the swing mechanism of the present invention;

[0030] Figure 4 It is a schematic diagram of the partial structure of the swing mechanism of the present invention;

[0031] Figure 5 It is a schematic diagram of the internal structure of the transmission box of the present invention;

[0032] Figure 6 It is a schematic diagram of the structure of the regulating device of the present invention.

[0033] Among them: stage swing screening device-1, adjustment device-2, first motor-2a, support collection box-3, opening and closing cover-4, swing mechanism-11, fixed plate-12, screen-13, support-111, transmission box-112, second motor-113, connecting shaft-114, support block-115, toggle member-116, contact rod-117, support guide member-118, linkage member-119, first side rod-1110, first connecting rod-1111, second side rod-1112, second connecting rod-1113, third side rod-1114, third connecting rod-1115, base-1116, driving pulley-1121, synchronous belt-1122, driven pulley-1123, bottom box-21, screw-22, sliding member-23, sliding box-24, cylinder-25, support member-26, connecting ear-27. DETAILED DESCRIPTION

[0034] In order to further explain the technical solution of the present invention, it is described in detail below through specific embodiments.

[0035] The invention provides a preparation process of an environmentally friendly EVA foam injection granule, and the specific steps are as follows: S1 raw material preparation: EVA resin: vinyl acetate content is 25%; foaming agent: azodicarbonamide; crosslinking agent: di-tert-butyl peroxide; other additives: antioxidant 1010, lubricant zinc stearate, masterbatch; S2 preliminary mixing: high-speed mixer: first pour the EVA resin, antioxidant and masterbatch into the high-speed mixer for preliminary mixing, the speed of the mixer is 750rpm, the time is 2.5 minutes, ensure that the EVA resin, the masterbatch and the antioxidant are initially mixed uniformly, and avoid color difference and oxidation problems in subsequent mixing; S3 adding the foaming agent and the crosslinking agent: adding gradually: after the preliminary mixing is completed, gradually adding the foaming agent and the crosslinking agent, and continuing to mix in the high-speed mixer, the speed is 700 rpm, the time is 2 minutes; add in stages: the foaming agent and cross-linking agent can be added in two or three times, and mix thoroughly after each addition to ensure that the components are evenly distributed; S4 internal mixing: the mixed materials are put into the internal mixer, the internal mixing temperature is 100℃, the time is 7 minutes, and then the segmented internal mixing is carried out, the mixed materials are put into the internal mixer in two or three sections, and the internal mixing time of each section is 3 minutes; S5 extrusion granulation: the internally mixed material is extruded into strips through an extruder, the extruder temperature is 90℃, and the cooled strip material is cut into pellets by a pelletizer; S6 cooling and shaping: the freshly extruded pellets are cooled by water cooling to avoid pellet adhesion, and the shaping equipment is used to ensure the stability of the pellet shape; S7 pellet screening: the shaped pellets are screened using automated screening equipment; S8 quality inspection: the density, hardness and elasticity of the pellets of qualified size after screening are tested.

[0036] See also Figure 1 The automated screening equipment includes a stage swing screening device 1, which can perform automated stage-by-stage swing screening on the rubber particles. The two ends of the bottom of the stage swing screening device 1 are connected to an adjusting device 2. A first motor 2a is provided in the middle of the front end of the adjusting device 2 for driving. The bottom of the adjusting device 2 is connected to a supporting collection box 3, which can support the adjusting device 2. An opening is provided in the middle of the supporting collection box 3, and an opening and closing cover 4 is locked on the left and right sides of the supporting collection box 3. The internal material can be taken out by opening the opening and closing cover 4.

[0037] See also Figure 2 The stage swing screening device 1 includes two sets of swing mechanisms 11 arranged opposite to each other, and a set of adjusting devices 2 are connected to the bottom of the swing mechanism 11. The inner sides of the two sets of swing mechanisms 11 are connected by three sets of fixed plates 12. The fixed plates 12 are provided with openings inside, and screens 13 are embedded in the openings. The mesh sizes of the three sets of screens 13 are different.

[0038] See also Figure 3-Figure 5The swing mechanism 11 includes a support 111 for supporting and connecting the adjustment device 2. A transmission box 112 is installed in the middle of the top of the support 111. A second motor 113 is arranged on the top of the transmission box 112. A connecting shaft 114 is arranged at the right end of the transmission box 112. A support block 115 for the connecting shaft 114 to penetrate is arranged at the right end of the bottom of the transmission box 112. The bottom of the connecting shaft 114 is hinged with a toggle member 116. The right end of the toggle member 116 is penetrated by a contact rod 117. The bottom of the contact rod 117 is against a semi-cylindrical support guide member 118. The bottom of the contact rod 117 is in a hemispherical shape. The bottom of the support guide member 118 is welded to the top of the support 111. A linkage member 119 is sleeved on the lower end of 117, and the linkage member 119 is L-shaped. The middle part of the upper end of the linkage member 119 is connected to the first side rod 1110. The two ends of the bottom of the first side rod 1110 are hinged to the second side rod 1112 through two groups of first connecting rods 1111, and the two ends of the bottom of the second side rod 1112 are hinged to the two ends of the third side rod 1114 through the second connecting rod 1113. The two ends of the third side rod 1114 are hinged to the base 1116 through the third connecting rod 1115. The bottom of the base 1116 is fixed to the top of the support 111, and the middle parts of the inner sides of the first side rod 1110, the second side rod 1112 and the third side rod 1114 are respectively connected to three groups of fixing plates 12;

[0039] A driving pulley 1121 connected to the output shaft of the second motor 113 is provided in the middle of the transmission box 112 . The outer side of the driving pulley 1121 rotates synchronously with the driven pulley 1123 through a synchronous belt 1122 . The middle of the driven pulley 1123 is connected to the connecting shaft 114 .

[0040] See also Figure 6 The adjusting device 2 includes a bottom box 21 arranged on the top of the supporting collection box 3, a screw rod 22 is arranged in the middle of the bottom box 21, one end of the screw rod 22 is connected to the output shaft of the first motor 2a outside the bottom box 21, the middle of the screw rod 22 is threadedly connected to the sliding member 23, a guide groove is opened in the middle of the top of the bottom box 21, the guide groove is penetrated by the sliding member 23, and the top of the sliding member 23 is connected to the sliding box 24, the left and right ends of the sliding box 24 are provided with a cylinder 25, the top of the cylinder 25 pushes out the rod and is hinged to the supporting member 26, the top of the sliding box 24 is penetrated by the supporting member 26, the bottom of the supporting member 26 is arc-shaped, the middle of the bottom end of the supporting member 26 is hinged to the sliding box 24 through the connecting ear 27, and the top of the supporting member 26 is connected to the support 111.

[0041] The specific implementation process is as follows:

[0042] When the rubber particles need to be screened, they are introduced by an external feeding device onto the screen 13 in the uppermost fixed plate 12 inside the stage swing screening device 1, and then the second motor 113 is started to start working. The second motor 113 drives the driving pulley 1121 to rotate, and the driving pulley 1121 drives the driven pulley 1123 to rotate synchronously through the synchronous belt 1122. The connecting shaft 114 in the middle of the driven pulley 1123 can rotate, and the contact rod 117 can be driven by the toggle member 116, and the contact rod 117 can contact the support guide member 118 at the bottom. The first side rod 1110 moves up and down in the shape of the contact rod 117 and the linkage member 119 during the movement. The first side rod 1110 can move with the second side rod 1112 through the first connecting rod 1111. At the same time, the second connecting rod 1113 on the second side rod 1112 moves with the third side rod 1114. The third side rod 1114 is supported by the third connecting rod 1115. When the three groups of side rods move, the fixed plate 12 connected to the inner side thereof can move with them to perform stage swing screening on the rubber particles through the screen in the middle.

[0043] The sieved rubber particles can fall into the support collection box 3, and the rubber particles in the support collection box 3 can be taken out by opening the opening and closing cover 4;

[0044] If it is necessary to clean the unqualified rubber particles on the screen 13, the first motor 2a can be started to rotate the screw 22. During the rotation of the screw 22, the sliding member 23 is driven to move the sliding box 24 to achieve position adjustment. Then, according to the required tilted position, a corresponding group of cylinders 25 inside the sliding box 24 are started to lift the supporting member 26. Under the action of the connecting ear 27, the tilt of the supporting member 26 is achieved, and the tilt of the top connecting swing mechanism 11, the fixed plate 12 and the screen 13 can be achieved, so that the unqualified rubber particles can be quickly discharged.

[0045] The above description is only a preferred example of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A process for preparing an environmentally friendly EVA foam injection granule, characterized in that: The specific steps are as follows: S1 Raw material preparation: EVA resin: vinyl acetate content is 10%-40%; foaming agent: azodicarbonamide; cross-linking agent: di-tert-butyl peroxide; other additives: antioxidant 1010, lubricant zinc stearate, masterbatch; S2 Preliminary mixing: High-speed mixer: Pour EVA resin, antioxidant 1010 and masterbatch into a high-speed mixer for preliminary mixing at a speed of 500-1000 rpm for 2-3 minutes; S3 Adding blowing agent and cross-linking agent: Gradually adding: After the initial mixing is completed, gradually add blowing agent and cross-linking agent, and continue mixing in the high-speed mixer at a speed of 500-800 rpm for 2-3 minutes; S4 Internal Mixing: Put the mixed materials into the internal mixer at a temperature of 90-110°C for 5-10 minutes, and then perform segmented internal mixing. Put the mixed materials into the internal mixer in two or three stages, and each stage of internal mixing lasts for 2-3 minutes. S5 extrusion granulation: the mixed material is extruded into strips through an extruder at a temperature of 80-100°C, and the cooled strips are cut into pellets through a pelletizer; S6 Cooling and shaping: Cool the freshly extruded particles by water cooling to avoid particle adhesion, and use shaping equipment to ensure the stability of particle shape; S7 colloid particle screening: the shaped colloid particles are screened by automatic screening equipment; S8 quality inspection: density, hardness and elasticity inspection of the qualified size of the rubber particles after screening; The automated screening equipment comprises a stage swing screening device, an adjustment device arranged at both ends of the bottom of the stage swing screening device, a support collection box connected to the bottom of the adjustment device, and an opening and closing cover arranged on the left and right sides of the support collection box, a first motor is arranged in the middle of the front end of the adjustment device for driving, and an opening is opened in the middle of the support collection box; The stage swing screening device comprises two sets of swing mechanisms arranged opposite to each other, a fixed plate arranged inside the two sets of swing mechanisms, and a screen arranged inside the fixed plate, and a set of adjustment devices are correspondingly connected to the bottom of the swing mechanism; The swing mechanism includes a support for support, a transmission box arranged at the top of the support, a second motor arranged at the top of the transmission box, a connecting shaft arranged at the right end inside the transmission box, a supporting block arranged at the bottom of the transmission box and penetrated by the connecting shaft, a toggle member connected to the bottom of the connecting shaft, a contact rod penetrating the other end of the toggle member, a supporting guide member abutting against the bottom of the contact rod and fixedly arranged on the top of the support, a linkage member arranged at the lower end of the contact rod, a first side rod connected to the other end of the linkage member, a first connecting rod hinged at both ends of the first side rod, a second side rod hinged at the other end of the first connecting rod, a second connecting rod hinged to the other end of the second side rod, a third side rod hinged at the other end of the second connecting rod, a third connecting rod hinged to the other end of the third side rod, and a base hinged to the other end of the third connecting rod, the bottom of the base is fixedly arranged on the top of the support, the bottom of the support is connected to the adjusting device, a group of fixing plates are respectively connected to the middle of the inner sides of the first side rod, the second side rod and the third side rod, and the supporting guide member is semi-cylindrical.

2. The preparation process of an environmentally friendly EVA foam injection granule according to claim 1, characterized in that: The linkage member is in an L shape.

3. The preparation process of an environmentally friendly EVA foam injection granule according to claim 2, characterized in that: A driving pulley connected to the output shaft of the second motor is arranged in the middle of the transmission box. The outer side of the driving pulley rotates synchronously with the driven pulley through a synchronous belt, and the middle of the driven pulley is connected to a connecting shaft.

4. The preparation process of an environmentally friendly EVA foam injection granule according to claim 1, characterized in that: The adjusting device includes a bottom box arranged on the top of the supporting collection box, a screw rod arranged in the middle of the bottom box and connected to the output shaft of the first motor, a sliding member threadedly connected to the middle of the screw rod, a sliding box connected to the top of the sliding member, cylinders arranged at both ends of the sliding box, a supporting member hinged to the ejection rod at the top of the cylinder, and a connecting ear arranged at the bottom of the supporting member and hinged to the inside of the sliding box.

5. The process for preparing an environmentally friendly EVA foam injection granule according to claim 4, characterized in that: A guide groove is provided in the middle of the top end of the bottom box, and the guide groove is penetrated by a sliding member.

6. The process for preparing an environmentally friendly EVA foam injection granule according to claim 5, characterized in that: The bottom of the support is in an arc shape.

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