CN117817877A - Continuous mixing method and device for ethylene-propylene-diene monomer heat insulation material under action of pulsating positive stress - Google Patents
Continuous mixing method and device for ethylene-propylene-diene monomer heat insulation material under action of pulsating positive stress Download PDFInfo
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- 229920002943 EPDM rubber Polymers 0.000 title claims abstract description 116
- 238000002156 mixing Methods 0.000 title claims abstract description 75
- 239000012774 insulation material Substances 0.000 title claims abstract description 47
- 238000000034 method Methods 0.000 title claims abstract description 39
- 230000009471 action Effects 0.000 title claims abstract description 30
- 239000000835 fiber Substances 0.000 claims abstract description 58
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 42
- 239000000463 material Substances 0.000 claims abstract description 40
- 239000011812 mixed powder Substances 0.000 claims abstract description 37
- 239000004642 Polyimide Substances 0.000 claims abstract description 36
- 229920001721 polyimide Polymers 0.000 claims abstract description 36
- 239000006229 carbon black Substances 0.000 claims abstract description 35
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 34
- 239000011810 insulating material Substances 0.000 claims abstract description 30
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 claims abstract description 19
- 239000003063 flame retardant Substances 0.000 claims abstract description 19
- 230000003712 anti-aging effect Effects 0.000 claims abstract description 18
- 230000008569 process Effects 0.000 claims abstract description 18
- 229940057995 liquid paraffin Drugs 0.000 claims abstract description 17
- 238000010008 shearing Methods 0.000 claims abstract description 10
- 238000004513 sizing Methods 0.000 claims abstract description 10
- 230000000694 effects Effects 0.000 claims abstract description 8
- 230000020169 heat generation Effects 0.000 claims abstract description 5
- 239000000843 powder Substances 0.000 claims description 57
- 238000003860 storage Methods 0.000 claims description 38
- 238000001125 extrusion Methods 0.000 claims description 22
- 230000002572 peristaltic effect Effects 0.000 claims description 16
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- 230000009467 reduction Effects 0.000 claims description 10
- 230000005540 biological transmission Effects 0.000 claims description 8
- 238000007599 discharging Methods 0.000 claims description 7
- 230000010349 pulsation Effects 0.000 claims description 6
- XMNIXWIUMCBBBL-UHFFFAOYSA-N 2-(2-phenylpropan-2-ylperoxy)propan-2-ylbenzene Chemical group C=1C=CC=CC=1C(C)(C)OOC(C)(C)C1=CC=CC=C1 XMNIXWIUMCBBBL-UHFFFAOYSA-N 0.000 claims description 4
- 238000001816 cooling Methods 0.000 claims description 4
- 238000010438 heat treatment Methods 0.000 claims description 4
- 238000004898 kneading Methods 0.000 claims description 4
- 239000011295 pitch Substances 0.000 claims description 3
- 230000004580 weight loss Effects 0.000 claims description 3
- AWYVETCHVQGXMB-UHFFFAOYSA-N (3-hydroxyphenyl) diphenyl phosphate Chemical group OC1=CC=CC(OP(=O)(OC=2C=CC=CC=2)OC=2C=CC=CC=2)=C1 AWYVETCHVQGXMB-UHFFFAOYSA-N 0.000 claims description 2
- OUBMGJOQLXMSNT-UHFFFAOYSA-N N-isopropyl-N'-phenyl-p-phenylenediamine Chemical group C1=CC(NC(C)C)=CC=C1NC1=CC=CC=C1 OUBMGJOQLXMSNT-UHFFFAOYSA-N 0.000 claims description 2
- 208000016261 weight loss Diseases 0.000 claims 1
- 238000000465 moulding Methods 0.000 abstract description 3
- 229920001971 elastomer Polymers 0.000 description 7
- 239000002245 particle Substances 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
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- 238000005516 engineering process Methods 0.000 description 5
- 238000004132 cross linking Methods 0.000 description 4
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- 238000000748 compression moulding Methods 0.000 description 3
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- 238000002679 ablation Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
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- 239000011159 matrix material Substances 0.000 description 2
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- 238000005979 thermal decomposition reaction Methods 0.000 description 1
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Abstract
The invention belongs to the technical field of molding and processing of heat-insulating materials, and relates to a continuous mixing method and device for an ethylene propylene diene monomer heat-insulating material under the action of pulsating positive stress. The ethylene propylene diene monomer heat insulation material comprises ethylene propylene diene monomer rubber, a vulcanizing agent, an anti-aging agent, a flame retardant, polyimide fibers, white carbon black and liquid paraffin. The mixing method comprises the following steps: premixing the vulcanizing agent, the anti-aging agent and the flame retardant to form mixed powder; continuously feeding the obtained mixed powder, the granular ethylene propylene diene monomer rubber, the polyimide fiber, the white carbon black and the liquid paraffin into an extruder based on the action of pulsating positive stress for continuous mixing; under the action of pulsating positive stress, the volume of the ethylene-propylene-diene monomer heat insulation material is continuously compressed and released, so that the sizing material is forced to be mixed and dispersed in an extruder with high efficiency; the topological structure of the continuous change of the rotor of the extruder based on the pulsating positive stress effect weakens the shearing acting force in the mixing process and reduces the shearing heat generation of the heat insulation material in the mixing process.
Description
Technical Field
The invention belongs to the technical field of molding and processing of heat insulation materials, and particularly relates to a continuous mixing method and device for an ethylene propylene diene monomer heat insulation material under the action of pulsating positive stress.
Background
The heat insulating layer is one of heat protecting materials for engine, and the inner heat insulating layer for solid rocket engine is one kind of non-metal heat insulating protecting material between the inner surface of the casing and the propellant, and has base material mainly ethylene propylene diene monomer rubber (EPDM) and nitrile rubber. Under the severe working condition that solid propellant fuel generates continuous high-temperature (higher than 3500K) and high-pressure (3-20 MPa or even higher) air flow, the heat insulation layer resists propellant gas scouring, inhibits surface combustion and prevents the shell from reaching the rubber-based composite material endangering the structural integrity of the shell through self thermal decomposition, so that the normal operation of the engine is ensured.
The EPDM heat insulating material is used as a special rubber material for military use, and the manufacturing process has certain specificity. First, fibrous fillers in insulation materials generally aggregate in the form of short filaments and have poor dispersibility. Secondly, the vulcanizing agent adopted by the EPDM heat-insulating material is dicumyl peroxide (DCP), and if the temperature is higher than 120 ℃ in the processing process, the vulcanizing agent can be rapidly decomposed and can carry out a crosslinking reaction with the base material EPDM, thereby influencing the post-forming of the heat-insulating material.
The mixing of the heat insulating material is mainly carried out in two modes, one is to mix the heat insulating material by an open mill, the filler and the rubber base material are uniformly mixed by the open mill, the labor intensity of operators is high, dust flying is serious, and the operation environment is bad; the other is a mixing process combining banburying and open milling, wherein the components except the vulcanizing agent are firstly mixed into master batch by an internal mixer, the vulcanizing agent is added in an open milling mode after the sizing material is cooled, the labor intensity of operators is reduced by adopting the mode, but the production mode is still intermittent production, and the uncontrollable factors are more. The two mixing modes mainly have the following problems: (1) The production efficiency is low, short-cut fibers which are not easy to disperse are added into the heat insulation material, and the single-pot mixing time is more than 1 hour; (2) The potential safety hazard is large, actions such as feeding, tapping, overturning and the like are operated manually, and at the moment, the palm and fingers of an employee are in close contact with the rotating roller for many times, so that the personal safety is influenced; (3) The labor intensity is high, the two modes have the operation of an open mill, and in order to ensure the uniformity of the rubber compound, the rubber compound must be thinned and communicated for many times; (4) The manual operation is more, the skill dependence of the open mill operation on operators is too great, and the open mill operation is easily influenced by human factors; (5) The batch mixing uniformity is poor, the uniformity of the mixed sizing material in each batch is different, and the stability of the product performance is influenced.
At present, the domestic and foreign continuous mixing technology is a technology formed by mutually combining two or three of a traditional open mill, an internal mixer and a double screw rod, and mainly has the following problems: (1) The premixing of sizing materials is realized through shearing force, the heat generation amount in the mixing process is large, and vulcanizing agents are added through open mill; (2) The mixing modes are combined, but still belong to batch mixing modes, the equipment scale is large and complex, and the overall mixing efficiency is low.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a continuous mixing method and device for an ethylene-propylene-diene monomer heat-insulating material under the action of pulsation positive stress, which realize continuous feeding of all components of the ethylene-propylene-diene monomer heat-insulating material by using a weightless feeding technology, and realize efficient, low-temperature and continuous mixing of the ethylene-propylene-diene monomer heat-insulating material by using the pulsation positive stress of mixing equipment, thereby effectively solving the difficulties of the prior processing technology.
According to a first aspect of the invention, there is provided a continuous mixing method of an ethylene-propylene-diene monomer heat-insulating material with a pulsating positive stress effect, wherein the ethylene-propylene-diene monomer heat-insulating material comprises ethylene propylene diene monomer rubber, a vulcanizing agent, an anti-aging agent, a flame retardant, polyimide fibers, white carbon black and liquid paraffin, and the method comprises the following steps:
(1) Premixing the vulcanizing agent, the anti-aging agent and the flame retardant to form mixed powder;
(2) Continuously feeding the mixed powder obtained in the step (1), the granular ethylene propylene diene monomer rubber, the polyimide fiber, the white carbon black and the liquid paraffin into an extruder based on the action of pulsating positive stress for continuous mixing; under the action of pulsating positive stress, the volume of the ethylene-propylene-diene monomer heat insulation material is continuously compressed and released, so that the sizing material is forced to be mixed and dispersed in an extruder with high efficiency; the continuously-changing topological structure of the extruder rotor weakens the shearing acting force in the mixing process and reduces the shearing heat generation of the heat insulation material in the mixing process.
Preferably, the ethylene propylene diene monomer insulation material comprises: 100 parts by mass of ethylene propylene diene monomer rubber, 5-20 parts by mass of polyimide fiber, 10-30 parts by mass of white carbon black, 20-40 parts by mass of mixed powder and 5-30 parts by mass of liquid paraffin.
Preferably, the vulcanizing agent is dicumyl peroxide; the anti-aging agent is N-isopropyl-N' -phenyl-p-phenylenediamine; the flame retardant is resorcinol-diphenyl phosphate polycondensate.
According to another aspect of the invention, there is provided a continuous mixing device for ethylene propylene diene monomer insulation material under the action of pulsating positive stress, comprising a power transmission system, a feeding system and an extrusion system;
the power transmission system comprises a motor, a coupler and a power reduction distributor which are sequentially connected;
the extrusion system comprises a screw I, a screw II and a machine barrel; the motor is connected with an input shaft of the power reduction distributor through a coupler; the power speed reducing distributor is provided with two output shafts which rotate in opposite directions and are respectively connected with the screw rod I and the screw rod II; the machine barrel is fixedly connected with the power speed reduction distributor; the screw I and the screw II are topological structures with continuously changing outer surfaces, the cross sections are circular, eccentric amounts exist with the screw axis, the screw I and the screw II comprise spiral sections and flat sections, the flat section structures are arranged between the spiral section structures, the screw pitches of the spiral sections gradually decrease along the extrusion direction, the screw I and the screw II are meshed with each other, and the screw I and the screw II are installed in an inner cavity of the machine barrel;
the feeding system comprises an ethylene propylene diene monomer feeding machine, a powder feeding machine I, a powder feeding machine II, a fiber feeding machine and a peristaltic pump; the machine barrel is provided with a feeding port I, a feeding port II and a feeding port III respectively, a feeding hopper I is fixedly arranged at the feeding port I, and a hopper II is fixedly arranged at the feeding port III; the outlets of the ethylene propylene diene monomer rubber feeder, the fiber feeder and the powder feeder II are positioned right above the hopper I, the discharging pipe of the peristaltic pump is connected with the cylinder feeding port II, and the discharging port of the powder feeder I is positioned right above the hopper II; the ethylene propylene diene monomer rubber storage bin is connected with the ethylene propylene diene monomer rubber feeding machine top, the fibre feeding machine top is connected with polyimide fiber storage bin, powder feeding machine II top is connected with mixed powder storage bin, powder feeding machine I top is connected with white carbon black storage bin, peristaltic pump top is connected with paraffin storage bin.
Preferably, the heating and cooling device is fixedly arranged on the outer wall surface of the machine barrel.
Preferably, the barrel inner cavity is a "≡shaped light hole.
Preferably, the ethylene propylene diene monomer rubber feeder, the fiber feeder, the powder feeder I and the powder feeder II are all weightless feeders.
According to another aspect of the present invention, there is provided a method for continuously kneading ethylene propylene diene monomer insulation material by any one of the apparatus, comprising the steps of:
(1) Ethylene propylene diene monomer is put into a hopper I from an ethylene propylene diene monomer storage bin through an ethylene propylene diene monomer feeder; polyimide fibers are put into a hopper I from a polyimide fiber storage bin through a fiber feeder; uniformly mixing a flame retardant, a vulcanizing agent and an anti-aging agent to obtain mixed powder, and then throwing the mixed powder into a hopper I through a powder feeder II from a mixed powder storage bin; white carbon black powder is put into a hopper II from a white carbon black storage bin through a powder feeder I; placing liquid paraffin into a paraffin storage bin;
(2) Setting the rotating speeds of a screw I and a screw II, sequentially starting an ethylene propylene diene monomer rubber feeder, a fiber feeder, a powder feeder II and a peristaltic pump, and respectively feeding ethylene propylene diene monomer rubber, polyimide fibers, mixed powder and liquid paraffin into a machine barrel for plasticizing, mixing and transporting;
(3) When the material is transported to a feeding port III, a powder feeder I is started again, and white carbon black powder is fed into a machine barrel; under the meshing rotation of the screw I and the screw II, the materials are continuously subjected to the pulsating normal stress between the screw and the machine barrel and between the two screws, so that plasticization and mixing are rapidly completed.
Preferably, the rotational speed of the screw I and the screw II is 200rpm or less, preferably 40rpm to 70rpm.
Preferably, the ethylene propylene diene monomer, polyimide fiber, mixed powder and white carbon black are fed in a weight loss type manner to control the feeding ratio of each component.
In general, the above technical solutions conceived by the present invention, compared with the prior art, enable the following beneficial effects to be obtained:
(1) The continuous mixing method and the device for the ethylene-propylene-diene monomer heat-insulating material under the action of the pulsating positive stress can continuously feed, mix and extrude all components of the ethylene-propylene-diene monomer heat-insulating material on line, realize continuous and automatic efficient mixing of the ethylene-propylene-diene monomer heat-insulating material, and effectively solve the problems of poor batch uniformity and unstable product performance in the traditional mixing process.
(2) According to the mixing principle of the ethylene-propylene-diene monomer heat-insulating material based on the pulsating positive stress effect, which is provided by the invention, not only can shearing acting force in the mixing process of the heat-insulating material be weakened and the temperature rise of a sizing material be reduced, but also the mixing and dispersing efficiency of fillers such as polyimide fibers, white carbon black and the like in matrix rubber can be greatly improved, the mixing time of the heat-insulating material is greatly reduced, the performance of the prepared ethylene-propylene-diene monomer heat-insulating material is more excellent, and the unit energy consumption is lower.
(3) The technology of the invention realizes continuous and automatic mixing of the ethylene-propylene-diene monomer heat insulation material, not only can reduce labor intensity and avoid dangerous operations such as manual feeding, rubber tapping, rubber turning and the like, and improves the safety in the mixing process, but also ensures that all mixing procedures of the heat insulation material are carried out in a closed environment, and environmental pollution is avoided.
Drawings
FIG. 1 is a schematic diagram of a continuous kneading apparatus for ethylene-propylene-diene monomer insulation material under the action of pulsating positive stress in an embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view of a pulsating positive stress extruder extrusion system in accordance with an embodiment of the present invention.
Fig. 3 is a schematic diagram of pulsating positive stress in an embodiment of the invention.
FIG. 4 is an ethylene propylene diene monomer insulation material prepared in the examples of the present invention.
The same reference numbers are used throughout the drawings to reference like elements or structures, wherein: 1-an ethylene propylene diene monomer rubber feeding machine; 2-a fiber feeder; 3-granular ethylene propylene diene monomer rubber storage bin; 4-polyimide fiber storage bin; 5-a crusher; 6-block ethylene propylene diene monomer rubber storage bin; 7-a powder mixer; 8-white carbon black storage bin; 9-a mixed powder storage bin; 10-a powder feeder I; 11-a powder feeder II; 12-paraffin storage bin; 13-peristaltic pump; 14-a feeding port I; 15-a hopper I; 16-a feeding port II; 17-feeding port III; 18-a hopper II; 19-an electric motor; 20-a power reduction distributor; 21-barrel; 22-screw I; 23-screw II; 24-a temperature control device; 25-die head; 26-extrusion port.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention. In addition, the technical features of the embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.
The invention relates to a continuous mixing method of ethylene propylene diene monomer heat insulation material under the action of pulsation positive stress, which comprises the steps of crushing ethylene propylene diene monomer rubber into particles, and premixing powder or particle components of vulcanizing agent, anti-aging agent, flame retardant and the like of the heat insulation material to form mixed powder; then, respectively and continuously feeding the granular ethylene propylene diene monomer rubber, the mixed powder, the polyimide fiber, the white carbon black, the liquid paraffin and the like into an extruder based on the action of positive pulse stress by using four feeders and a peristaltic pump according to a proportion for continuous mixing; the extruder with the pulsating positive stress effect consists of a power transmission system, a feeding system, an extrusion system and the like; wherein the extrusion system mainly comprises two screws and a machine barrel; the power transmission system consists of a motor, a coupler and a power distributor; the feeding system consists of an ethylene propylene diene monomer feeding machine, a powder feeding machine I, a powder feeding machine II, a fiber feeding machine and a peristaltic pump.
The outer surface of the screw is of a continuously-changing topological structure, the screw consists of a spiral section and a straight section, the cross section of the screw is an eccentric circle, and an 'infinity' shaped unthreaded hole is formed in the machine barrel; the two screws are meshed with each other and are arranged in the inner cavity of the machine barrel, and in the rotating process of the screws, a pulsation normal stress effect is generated in a cavity of the extrusion system; ethylene propylene diene monomer rubber, polyimide fiber, white carbon black, mixed powder, liquid paraffin and the like of the heat insulating material are mixed and mixed into the heat insulating material under the action of pulsating positive stress, and the volume of the heat insulating material is continuously compressed and released under the action of pulsating positive stress, so that the polyimide fiber, the white carbon black, the flame retardant and other powder materials can be forced to be mixed and dispersed in ethylene propylene diene monomer rubber efficiently; the continuously-changed topological structure of the rotor greatly weakens the shearing acting force in the mixing process, reduces the shearing heat generation of the heat insulation material in the mixing process, and ensures that the continuous mixing of the ethylene-propylene-diene monomer heat insulation material has the characteristic of low-temperature mixing.
The invention discloses a continuous mixing method of an ethylene propylene diene monomer heat insulation material under the action of pulsating positive stress, which comprises the following steps:
s1: crushing the block ethylene propylene diene monomer into small particles by using a crusher to prepare granular ethylene propylene diene monomer;
s2: the flame retardant, vulcanizing agent, anti-aging agent and other powder or granular materials of the heat insulating material are premixed uniformly by using a stirrer to prepare mixed powder;
s3: setting the temperature and the rotating speed of an extruder with the action of the pulsating positive stress, and starting the extruder after the temperature reaches the set value;
s4: feeding the granular ethylene propylene diene monomer into an extrusion system under the action of pulsating positive stress from a feeding port I by a ethylene propylene diene monomer feeding machine, a polyimide fiber feeding machine and a mixed powder feeding machine II; liquid paraffin is fed into the extrusion system from a feeding port II by a peristaltic pump; white carbon black is fed into an extrusion system from a feeding port III by a feeding machine I;
s5: the components such as ethylene propylene diene monomer rubber, polyimide fiber, white carbon black, vulcanizing agent, anti-aging agent, flame retardant, liquid paraffin and the like which are added into an extruder with the action of pulsating positive stress are continuously mixed, and the heat insulating material with uniform mixing is extruded from an extrusion opening of the extruder.
In some embodiments, the thermal insulation material is formulated as follows: 100 parts by mass of ethylene propylene diene monomer rubber, 5-20 parts by mass of polyimide fiber, 10-30 parts by mass of white carbon black, 20-40 parts by mass of mixed powder and 5-30 parts by mass of paraffin.
In some embodiments, the extruder is operated at a temperature ranging from room temperature to 150℃and at a speed ranging from 200rpm or less.
In some embodiments, a temperature control device is mounted externally to the extruder barrel to control the temperature of the insulation during mixing.
In some embodiments, the feeding machines of ethylene propylene diene monomer rubber, polyimide fiber, mixed powder and white carbon black all control the feeding proportion and the feeding precision of each component in a weight loss type feeding mode.
Examples
As shown in fig. 1, the mixing equipment for continuous mixing of ethylene-propylene-diene monomer heat insulation materials provided by the invention under the action of pulsating positive stress comprises a power transmission system, a feeding system, an extrusion system, a temperature control system and the like. The power transmission system mainly comprises a motor 19, a coupler 3 and a power reduction distributor 20; the temperature control system is mainly a heating and cooling device 24 of a machine barrel; the extrusion system mainly comprises a screw I22, a screw II 23 and a machine barrel 21; the feeding system mainly comprises an ethylene propylene diene monomer feeding machine 1, a powder feeding machine I10, a powder feeding machine II 11, a fiber feeding machine 2 and a peristaltic pump 13. The motor 19 is connected with an input shaft of the power reduction distributor 20 through a coupler; the power speed reducing distributor 20 is provided with two output shafts which rotate in opposite directions and are respectively connected with a screw I22 and a screw II 23 through splines; the machine barrel 21 is fixedly connected with the power reduction distributor 20 through a flange plate; screw I22 and screw II 23 are mounted in the inner cavity of barrel 21; the heating and cooling device 24 is fixedly arranged on the outer wall surface of the machine barrel 21; the die head 25 is fixedly connected with the machine barrel 21 through a flange plate; the machine barrel 21 is respectively provided with a feeding port I14, a feeding port II 16 and a feeding port III 17, a feeding hopper I15 is fixedly arranged at the feeding port I14, and a hopper II 18 is fixedly arranged at the feeding port III 17; the ethylene propylene diene monomer rubber feeding machine 1, the fiber feeding machine 2, the powder feeding machine I10, the powder feeding machine II 11 and the peristaltic pump 13 are positioned above the machine barrel 21, wherein the outlets of the ethylene propylene diene monomer rubber feeding machine 1, the fiber feeding machine 2 and the powder feeding machine II 11 are positioned right above the hopper I, the discharging pipe of the peristaltic pump 13 is connected with the machine barrel feeding port II, and the discharging port of the powder feeding machine I10 is positioned right above the hopper II; the granular ethylene propylene diene monomer rubber storage bin 3, the polyimide fiber storage bin 4, the white carbon black storage bin 8 and the mixed powder storage bin 9 are respectively positioned right above hoppers of the ethylene propylene diene monomer rubber feeder 1, the fiber feeder 2, the powder feeder I10 and the powder feeder II 11, and an outlet of the paraffin storage bin 12 is connected with a feed inlet of the peristaltic pump 13.
The screw rod I22 and the screw rod II 23 are topological structures with continuously-changed outer surfaces, the cross sections of the screw rod I and the screw rod II are circular, and a certain eccentric amount e exists between the screw rod I and the screw rod II and the screw rod axis, as shown in figures 1 and 2, the screw rod I and the screw rod II are composed of spiral sections and flat sections, the flat section structures are arranged between the spiral section structures, and the screw pitch of the spiral sections is gradually reduced along the extrusion direction. The screw I22 and the screw II 23 have the same structure, the spiral directions are opposite, the screw I and the screw II are meshed with each other and are arranged in the inner cavity of the stator, and the rotation directions of the screw I and the screw II are opposite.
The inner cavity of the machine barrel 21 is an 'infinity' type unthreaded hole, as shown in figure 2, the surface of the inner cavity is of a smooth structure, and a minimum gap delta exists between the inner wall surface and the screw rod 1 And a maximum gap delta 2 。
Further, the rotation speed range of the screw I22 and the screw II 23 is less than or equal to 200rpm, and the optimal rotation speed range is 40-70rpm.
Further describing, the temperature control system is divided into five control areas on the machine barrel 21 along the extrusion direction, wherein the temperature of each temperature control area ranges from room temperature to 200 ℃, and the temperature control precision is +/-2 ℃.
Further, the ethylene propylene diene monomer blocks stored in the storage bin 6 are crushed into small particles by the crusher 5, and then the ethylene propylene diene monomer blocks are fed into the machine barrel by the ethylene propylene diene monomer feeder 1.
Further, the raw materials of the heat insulating material contain various powder components, the powder mixer 7 is used for pre-mixing various powder materials such as flame retardant, vulcanizing agent, anti-aging agent, coupling agent and the like, and then the powder feeder II 11 is used for feeding the mixed powder materials into the machine barrel.
Further describing, the ethylene propylene diene monomer rubber feeder 1, the fiber feeder 2, the powder feeder I10 and the powder feeder II 11 are all in a weightless feeding mode, so as to realize online accurate compounding of all components of the heat insulation material.
The continuous mixing steps of the ethylene propylene diene monomer heat insulation material are as follows:
step 1: 10000g of ethylene propylene diene monomer rubber in a storage bin 6 of the ethylene propylene diene monomer rubber is put into a crusher 5 to be crushed into particles, and then the particle ethylene propylene diene monomer rubber is put into a hopper of an ethylene propylene diene monomer rubber feeder 1 from a storage bin 3;
step 2: 3000g of polyimide fibers are put into a hopper of a fiber feeder 2 from a polyimide fiber storage bin 4; 5000g of various powder materials such as a flame retardant, a vulcanizing agent, an anti-aging agent, a coupling agent and the like are put into a powder material mixer 7 to be uniformly mixed, and then the uniformly mixed powder materials are put into a hopper of a powder material feeder II 11 through a mixed powder material storage bin 9;
step 3: 5000g of white carbon black powder is put into a hopper of a powder feeder I10 from a white carbon black storage bin 8; 1000g of liquid paraffin was put into the paraffin storage bin 12;
step 4: the temperature of the temperature control device on the machine barrel 21 is set to 40 ℃, 50 ℃,40 ℃ and 50 ℃ in sequence along the extrusion direction, and the rotating speeds of the screw I22 and the screw II 23 are set to 60rpm;
step 5: starting a host machine of continuous mixing equipment, and sequentially starting an ethylene propylene diene monomer rubber feeder 1, a fiber feeder 2, a powder feeder II 11 and a peristaltic pump 13, and respectively feeding mixed powder of ethylene propylene diene monomer rubber, polyimide fiber, a flame retardant, a vulcanizing agent, an anti-aging agent, a coupling agent and the like and paraffin and the like into a machine barrel 21 for plasticizing, mixing and transporting;
step 6: and when the material is conveyed to a feeding port III 17, the powder feeder I10 is started again, and the white carbon black powder is fed into the machine barrel 21. Under the meshing rotation of the two screws, the materials are continuously subjected to the action of pulsating positive stress applied between the screws and the machine barrel and between the two screws, and the materials are driven to carry out positive displacement transportation of which the velocity gradient vector approaches to the flowing direction, so that plasticization and mixing are rapidly completed, and a large amount of powder and polyimide fibers are rapidly dispersed in an ethylene propylene diene monomer rubber matrix; FIG. 3 is a schematic diagram of pulsating positive stress in an embodiment of the invention;
step 7: the materials were extruded from the extrusion port 26 of the die head 25 under the extrusion pushing action of the screw, and finally the obtained materials were subjected to compression molding and crosslinking molding to obtain heat insulating materials, the properties of which are shown in table 1. FIG. 4 is an ethylene propylene diene monomer insulation material prepared in the examples of the present invention.
Comparative example 1
The comparison is made by using an open mill to prepare an ethylene propylene diene monomer heat insulation material, and the method comprises the following steps:
step 1: 200g of ethylene propylene diene monomer rubber, 40g of white carbon black, 20g of polyimide fiber, 80g of mixed powder of flame retardant, vulcanizing agent, anti-aging agent, coupling agent and the like and 25g of paraffin are weighed;
step 2: setting the rotating speed of an open mill to be 35rpm, setting the temperature to be 30 ℃, and starting the open mill to plasticate the EPDM rubber material for 3min;
step 3: sequentially adding the white carbon black, the polyimide fiber, the paraffin and the mixed powder into an open mill according to the sequence, and mixing for 50min;
step 4: and after the sizing materials are uniformly mixed, carrying out thinning and passing on the materials for 3min, and finally carrying out compression molding and crosslinking forming on the prepared materials to prepare the heat insulation material, wherein the properties of the heat insulation material are shown in the table 1.
Comparative example 2
The comparison is made by using an internal mixer and an open mill to prepare an ethylene propylene diene monomer heat insulation material, and the method comprises the following steps:
step 1: 600g of ethylene propylene diene monomer rubber, 120g of white carbon black, 60g of polyimide fiber, 240g of mixed powder of flame retardant, anti-aging agent, coupling agent and the like, 75g of paraffin and 30g of vulcanizing agent are weighed;
step 2: setting the rotation speed of the internal mixer to be 30rpm, setting the temperature to be 40 ℃, starting the internal mixer to plasticate the EPDM sizing material for 3min;
step 3: sequentially adding white carbon black, polyimide fiber, paraffin and mixed powder into an internal mixer according to the sequence, mixing for 20min, and discharging materials;
step 4: setting the rotating speed of an open mill at 35rpm and the temperature at 30 ℃, starting the open mill to continuously mix materials discharged from the internal mixer, adding a vulcanizing agent, and mixing for 10min;
step 5: and after the sizing materials are uniformly mixed, carrying out thinning and passing on the materials for 3min, and finally carrying out compression molding and crosslinking forming on the prepared materials to prepare the heat insulation material, wherein the properties of the heat insulation material are shown in the table 1.
Table 1 properties of the heat insulating materials prepared in examples and comparative examples
| Numbering device | Density g/cm 3 | Tensile Strength/MPa | Elongation at break/% | Ablation rate/mm/s |
| Examples | 1.040 | 8.12 | 787.7 | 0.078 |
| Comparative example 1 | 1.036 | 6.74 | 678.4 | 0.087 |
| Comparative example 2 | 1.040 | 6.54 | 657.4 | 0.085 |
As can be seen from Table 1, the tensile strength of the ethylene-propylene-diene monomer heat insulation material prepared by the mixing process of the open mill and the internal mixer and the open mill of the traditional mixing process is improved by 20.5% and 24.2%, the elongation at break is improved by 16.1% and 19.8%, the ablation rate is improved by 10.3% and 8.2%, and the density of the heat insulation material is basically consistent with that of the heat insulation material prepared by the traditional mixing process.
It will be readily appreciated by those skilled in the art that the foregoing description is merely a preferred embodiment of the invention and is not intended to limit the invention, but any modifications, equivalents, improvements or alternatives falling within the spirit and principles of the invention are intended to be included within the scope of the invention.
Claims (10)
1. The continuous mixing method of the ethylene-propylene-diene monomer heat-insulating material with the pulsation positive stress effect comprises ethylene-propylene-diene monomer rubber, a vulcanizing agent, an anti-aging agent, a flame retardant, polyimide fibers, white carbon black and liquid paraffin, and is characterized by comprising the following steps of:
(1) Premixing the vulcanizing agent, the anti-aging agent and the flame retardant to form mixed powder;
(2) Continuously feeding the mixed powder obtained in the step (1), the granular ethylene propylene diene monomer rubber, the polyimide fiber, the white carbon black and the liquid paraffin into an extruder based on the action of pulsating positive stress for continuous mixing; under the action of pulsating positive stress, the volume of the ethylene-propylene-diene monomer heat insulation material is continuously compressed and released, so that the sizing material is forced to be mixed and dispersed in an extruder with high efficiency; the continuously-changing topological structure of the extruder rotor weakens the shearing acting force in the mixing process and reduces the shearing heat generation of the heat insulation material in the mixing process.
2. The continuous mixing method of the ethylene-propylene-diene monomer heat insulation material with the pulsation positive stress effect according to claim 1, wherein the ethylene-propylene-diene monomer heat insulation material comprises: 100 parts by mass of ethylene propylene diene monomer rubber, 5-20 parts by mass of polyimide fiber, 10-30 parts by mass of white carbon black, 20-40 parts by mass of mixed powder and 5-30 parts by mass of liquid paraffin.
3. The continuous mixing method of the ethylene-propylene-diene monomer heat insulation material with the pulsating positive stress action according to claim 1, wherein the vulcanizing agent is dicumyl peroxide; the anti-aging agent is N-isopropyl-N' -phenyl-p-phenylenediamine; the flame retardant is resorcinol-diphenyl phosphate polycondensate.
4. The continuous mixing device for the ethylene propylene diene monomer heat insulation material under the action of the pulsating positive stress is characterized by comprising a power transmission system, a feeding system and an extrusion system;
the power transmission system comprises a motor, a coupler and a power reduction distributor which are sequentially connected;
the extrusion system comprises a screw I, a screw II and a machine barrel; the motor is connected with an input shaft of the power reduction distributor through a coupler; the power speed reducing distributor is provided with two output shafts which rotate in opposite directions and are respectively connected with the screw rod I and the screw rod II; the machine barrel is fixedly connected with the power speed reduction distributor; the screw I and the screw II are topological structures with continuously changing outer surfaces, the cross sections are circular, eccentric amounts exist with the screw axis, the screw I and the screw II comprise spiral sections and flat sections, the flat section structures are arranged between the spiral section structures, the screw pitches of the spiral sections gradually decrease along the extrusion direction, the screw I and the screw II are meshed with each other, and the screw I and the screw II are installed in an inner cavity of the machine barrel;
the feeding system comprises an ethylene propylene diene monomer feeding machine, a powder feeding machine I, a powder feeding machine II, a fiber feeding machine and a peristaltic pump; the machine barrel is provided with a feeding port I, a feeding port II and a feeding port III respectively, a feeding hopper I is fixedly arranged at the feeding port I, and a hopper II is fixedly arranged at the feeding port III; the outlets of the ethylene propylene diene monomer rubber feeder, the fiber feeder and the powder feeder II are positioned right above the hopper I, the discharging pipe of the peristaltic pump is connected with the cylinder feeding port II, and the discharging port of the powder feeder I is positioned right above the hopper II; the ethylene propylene diene monomer rubber storage bin is connected with the ethylene propylene diene monomer rubber feeding machine top, the fibre feeding machine top is connected with polyimide fiber storage bin, powder feeding machine II top is connected with mixed powder storage bin, powder feeding machine I top is connected with white carbon black storage bin, peristaltic pump top is connected with paraffin storage bin.
5. The continuous mixing device for the ethylene-propylene-diene monomer heat insulation material with the pulsating positive stress action according to claim 4, wherein a heating and cooling device is fixedly arranged on the outer wall surface of the machine barrel.
6. The continuous mixing device for the ethylene-propylene-diene monomer heat insulation material with the pulsating positive stress action according to claim 4, wherein the inner cavity of the machine barrel is an "-infinity" shaped unthreaded hole.
7. The continuous mixing device for the ethylene propylene diene monomer heat insulation material with the pulsating positive stress effect according to claim 4, wherein the ethylene propylene diene monomer rubber feeder, the fiber feeder, the powder feeder I and the powder feeder II are all weightless feeders.
8. A method for continuously kneading ethylene-propylene-diene monomer heat insulating material by using the apparatus according to any one of claims 4 to 7, comprising the steps of:
(1) Ethylene propylene diene monomer is put into a hopper I from an ethylene propylene diene monomer storage bin through an ethylene propylene diene monomer feeder; polyimide fibers are put into a hopper I from a polyimide fiber storage bin through a fiber feeder; uniformly mixing a flame retardant, a vulcanizing agent and an anti-aging agent to obtain mixed powder, and then throwing the mixed powder into a hopper I through a powder feeder II from a mixed powder storage bin; white carbon black powder is put into a hopper II from a white carbon black storage bin through a powder feeder I; placing liquid paraffin into a paraffin storage bin;
(2) Setting the rotating speeds of a screw I and a screw II, sequentially starting an ethylene propylene diene monomer rubber feeder, a fiber feeder, a powder feeder II and a peristaltic pump, and respectively feeding ethylene propylene diene monomer rubber, polyimide fibers, mixed powder and liquid paraffin into a machine barrel for plasticizing, mixing and transporting;
(3) When the material is transported to a feeding port III, a powder feeder I is started again, and white carbon black powder is fed into a machine barrel; under the meshing rotation of the screw I and the screw II, the materials are continuously subjected to the pulsating normal stress between the screw and the machine barrel and between the two screws, so that plasticization and mixing are rapidly completed.
9. The method for continuously kneading ethylene-propylene-diene monomer insulation material according to claim 8, wherein the rotational speed of the screw i and the screw ii is 200rpm or less, preferably 40rpm to 70rpm.
10. The method for continuously mixing ethylene-propylene-diene monomer (EPDM) heat-insulating material according to claim 8, wherein the feeding ratio of each component is controlled by a weight-loss type feeding mode of all ethylene-propylene-diene monomer (EPDM), polyimide fiber, mixed powder and white carbon black.
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|---|---|---|---|
| CN202311768922.2A CN117817877A (en) | 2023-12-21 | 2023-12-21 | Continuous mixing method and device for ethylene-propylene-diene monomer heat insulation material under action of pulsating positive stress |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311768922.2A CN117817877A (en) | 2023-12-21 | 2023-12-21 | Continuous mixing method and device for ethylene-propylene-diene monomer heat insulation material under action of pulsating positive stress |
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