CN102059767A - System and method for introducing discontinuous foaming agent multiple times - Google Patents
System and method for introducing discontinuous foaming agent multiple times Download PDFInfo
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- CN102059767A CN102059767A CN2010105323364A CN201010532336A CN102059767A CN 102059767 A CN102059767 A CN 102059767A CN 2010105323364 A CN2010105323364 A CN 2010105323364A CN 201010532336 A CN201010532336 A CN 201010532336A CN 102059767 A CN102059767 A CN 102059767A
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Abstract
The invention relates to a system and method for introducing a discontinuous foaming agent multiple times, belonging to the field of high polymer foamed plastics processing. The system comprises a gas source, a foaming agent injection port and a pipeline system connected between the gas source and the foaming agent injection port, wherein the pipeline system is provided with a gas booster and at least two gas collecting pots which are mutually connected in series, and an on-off valve is respectively arranged between the gas collecting pots; and a control system can be used for receiving a signal from high polymer material processing equipment, calculating the pressure in the gas connecting pots according to a processing requirement and the volumes of the gas collecting pots, controlling the action of the gas booster to adapt to a high polymer material processing process and outputting a signal to control a stop valve for opening and closing the inlet or the outlet of the gas collecting pots so as to realize the accurate control on the foaming agent injection quantity and the multiple injections of a definite quantity of foaming agent within an injection molding period. The invention has the advantages of simple design, convenience of operation, lower cost and convenience of realization of industrial production and is suitable for various specifications of injection molding machines.
Description
Technical field
The present invention relates to macromolecule foamed plastics processing, more particularly, relate to and be used in the system and method for in the processing of macromolecule foamed plastics blowing agent being introduced macromolecular material.
Background technology
Can use multiple technologies that macromolecular material is processed, comprise extrude, injection moulding, blowing, calendering etc., wherein extrude and be injected into two kinds of the most frequently used processing of high molecular material technology.Injection mo(u)lding is meant at sealing machine barrel inner macromolecule material under the spiro rod plasticizing effect that heat is conducted or can be rotated in machine barrel, melt polymer material, high speed and high pressure is injected into plastic melt in the closed mold cavity under plunger or screw acting then, obtains forming method with the corresponding to plastic part of die cavity through cooling and shaping.Nearly all thermoplastic macromolecule material can injection mo(u)lding, and 80% above high performance engineering plastics is by injection mo(u)lding.Injection mo(u)lding is a kind of production process of noncontinuity.In an injection cycle, comprise the screw rod rotation macromolecular material of plasticating, and will plastify good macromolecular material and gather, and screw rod stops the rotation, will gather the macromolecular material of getting well and be injected into technical process such as mold cavity.In order further to reduce the weight of high molecular products, save cost, reduce the shrinkage factor of injection-molded item and improve buckling deformation, physical blowing agent can be introduced the macromolecule melt in the injection screw, mixing effect by screw rod forms macromolecule/blowing agent homogeneous phase solution, homogeneous phase solution is injected mold cavity, preparation macromolecular material foaming product behind the cooling and shaping.Particularly for the high crystalline macromolecular material, or expensive engineering plastics, adopt frothing injection technology to reduce cost and to improve product properties especially suitable.In the frothing injection technical process, since screw rod rotation and be discontinuous operating process to the plasticizing of macromolecular material, therefore, in order to obtain uniform foaming product, require the introducing speed of blowing agent to need to be complementary, and be discontinuous introducing process with rotatablely moving of injection screw.Many traditional blowing agent drawing-in systems are introduced macromolecular material in the machine barrel continuously to blowing agent, this continuous introduction system may lack control on the percentage of the blowing agent that injects macromolecular material, and may cause the uneven distribution of blowing agent in macromolecular material.The uneven distribution of blowing agent may cause the viscosity of the macromolecular material in extruding machine to change, and this guarantees to bring problem to production stability and quality of item.
The patent No. of Trexel company in February, 2000 application is US6602063B1, name is called in the patent of " discontinuous blowing agent diliversy system and method " and discloses a kind of plunger case and piston that can limit the blowing agent fixed dosage that comprise, continuous source of the gas and the pipe-line system of injection moulding and the discontinuous blowing agent drawing-in system of some stop valves, utilize this system can realize the discontinuous processing of high molecular material process of the discontinuous injection of blowing agent (as injection moulding and blowing) by the break-make of stop valve, the adding speed of blowing agent is according to the temperature and pressure value of the plunger gas in the jar of measuring, thereby controls the charge velocity of blowing agent through the movement rate that the back control piston is calculated in control system analysis.(the N particularly because physical blowing agent
2, CO
2, supercritical fluid) molecular weight less, flow rate of gas is very fast, open at stop valve instantaneous because pressure reduction, the blowing agent of plunger case inner sealing can be introduced in the macromolecule melt very soon, adopts the introducing speed of the extremely difficult accurate control gas of this kind technical process.The patent No. of the said firm's application in February calendar year 2001 is US6926507B2, name is called in the patent of " blowing agent dilivery system " and discloses a kind of blowing agent drawing-in system that comprises bypath system, realize the discontinuous injection of blowing agent by the break-make bypass valve, but can not realize injecting the accurate metering and the charge velocity control of blowing agent.Trexel company applied for that the patent No. was US7144532B2 in 2002 10, name is called " blowing agentintroduction system and method ", and the patent No. of in August, 2000 application is US6616434B1, name is called in the patent of " blowing agent introduction system " and discloses a kind of air collector that comprises, a pressure-regulating valve, a device for pressure measurement and the control system that can pass through input and output signal controlled pressure control valve adjusting air collector internal pressure greater than the injection machine internal pressure, and utilize this control system blowing agent to be introduced the blowing agent drawing-in system and the method for processing of high molecular material process.The blowing agent drawing-in system and the method for this patent disclosure, by regulating the pressure in the air collector, and the air collector volume of determining, realize introducing the accurate control of foaming dosage, in this blowing agent drawing-in system and method, the on-off valve of air collector outlet and/or inlet is closed and/or opened once is a gas injection cycle, can only be in a gas injection cycle once with the macromolecule melt in the blowing agent injection injection machine that is collected in the air collector, if the blowing agent that will be collected at once in the air collector in a fusion cycle of injection machine is incorporated in the macromolecule melt, because the diffusion velocity of gas is very fast, as for N
2, when air collector internal pressure and macromolecule melt pressure ratio are 2, with 11.5g N
2Introduce the time of macromolecule melt and have only 1.0 * 10
-6Ms, and for discontinuous processing technologys such as injection mouldings, the time of a fusion cycle is generally 1～10s, so just can not guarantee that gas is evenly introduced in whole fusion cycle, cause local gas concentration height, after initial mixing was finished by screw rod shearing, the melt of follow-up plasticizing can only rely on the diffusion of gas in storage cavity, reach macromolecule melt/blowing agent homogeneous phase solution, this will need long time.Will cause the uneven distribution of storing indoor gas and melt like this, local gas concentration height, can't be dissolved in fully in the melt, and the part does not contain blowing agent, thereby influence the uniformity of goods and stablizing of production technology, so this technical scheme only is applicable on the little injection machine, screw diameter is on 40mm or following injection machine; This gas drawing-in system and method also disclose a kind of technical scheme in addition, promptly in an injection cycle, carry out twice or twice above gas collection and gas injection process, attempt to solve above-mentioned deficiency, so just need in a fusion cycle, repeatedly start and stop booster, and cooperation is simultaneously repeatedly opened and/or the on-off valve of closure set gas tank inlet and/or outlet, but because the fusion cycle of common injection machine was less than 30 seconds, even less than 10 seconds, if in a fusion cycle, will realize repeatedly gas boosting, steps such as introducing are just to the pressure degree of regulation of the dynamic response process of the booster of blowing agent drawing-in system, the control accuracy of on-off valve operation precision and control system etc. has proposed very high requirement, increased the machining accuracy of booster in this gas drawing-in system so undoubtedly, automatically controlled precision, the requirement of on-off valve action response precision and control system, thereby the complexity and the production cost of a whole set of gas drawing-in system have been increased, and usually gas boosting reaches the stable time needs 10～20 seconds, so this technical scheme implements to exist sizable difficulty.
Summary of the invention
The object of the invention is to provide a kind of discontinuous blowing agent repeatedly drawing-in system and method, particularly this blowing agent drawing-in system and method can be complementary with the discontinuous process of macromolecular material, in a process-cycle, will with the quality of item quantitative really blowing agent that adapts, repeatedly inject the macromolecular material of discontinuous processing discontinuously, in the macromolecule melt in the injection machine machine barrel.
To achieve these goals, the present invention has taked following technical scheme.Native system comprises that one contains the source of the gas of blowing agent, a pipeline and a control system that is positioned at gas injection port, connection source of the gas and gas injection port on the injection machine machine barrel.On the pipeline that connects source of the gas and gas injection port, be equipped with:
Gas booster with entrance and exit, the inlet of gas booster is connected with source of the gas, the outlet of gas booster at least two air collectors that are installed in series, the cumulative volume of each air collector is greater than 20ml;
The outlet of last air collector of series connection is connected with the gas injection port pipeline mutually, on the connecting pipeline of between on-off valve is installed;
The inlet of first air collector of series connection is connected with the outlet of booster mutually, on the connecting pipeline of between on-off valve is installed;
Between each air collector of series connection on-off valve is installed also mutually;
With air collector that gas injection port is connected on a pressure measuring element is installed at least, this pressure measuring element can be to the control system output signal;
Booster and each on-off valve all can be accepted the output signal of control system.
The number of the air collector that described outlet polyphone at booster is installed is 2～10, and suitable is 3～5.
Use said system that blowing agent is repeatedly introduced in the injection machine inner macromolecule melt, specifically this method step is as follows:
1) close the on-off valve that is connected with gas injection port, open other all on-off valves, source of the gas carries out pneumatic compression to all air collectors;
2) when the pressure in the air collector reaches greater than injection machine inner macromolecule melt back pressure 1-50MPa, close all on-off valves;
3) screw in injection molding machine begins the rotation plasticizing, plasticizing edge, screw rod limit moves axially, control system is according to the displacement of screw rod in machine barrel, repeatedly open on-off valve between last air collector and the gas injection port in whole spiro rod plasticizing stroke inner control, the blowing agent of doses is introduced in the macromolecular material melt in the injection machine by control repeatedly; In injection machine, introduce blowing agent at every turn, when the pressure in last air collector equates with melt pressure in the injection machine, the on-off valve of then closing between last air collector and the gas injection port finishes to introduce, open the on-off valve between each air collector then, make blowing agent between each air collector, spread and reach new pressure balance, wait for next time and introducing;
4) under the rotation plastication of screw in injection molding machine, repeatedly blowing agent of Zhu Ruing and macromolecule melt are uniformly mixed to form homogeneous phase solution, are transported to the storage cavity of screw front end.
Before the plasticizing beginning, the gas pressure in the air collector should be greater than injection machine inner macromolecule melt back pressure 5-30Mpa, suitable 10-20MPa.
Among the present invention, in an injection cycle, open on-off valve and in injection machine, introduce the number of times of blowing agent and be no less than 3 times, be fit to be no less than 5 times.
In step 3, when screw rod retreats into the 1%-50% of plasticizing stroke, open for the first time on-off valve blowing agent is introduced in the macromolecule melt in the injection machine; When screw rod retreats into the 50-90% of plasticizing stroke, open the on-off valve between last air collector and the gas injection port for the last time, the blowing agent of final dose in the fusion cycle is introduced injection moulding reach in the interior macromolecule melt.
The present invention has the following advantages:
The present invention goes into macromolecule melt quality in the die cavity according to per injection in the injection cycle, and the interpolation of the blowing agent in required introducing injection moulding machine barrel percentage, calculate the blowing agent quality that in an injection cycle, needs to introduce injection machine inner macromolecule melt.According to predetermined air collector volume, the macromolecule melt back pressure that processing needs, and the blowing agent quality and the equation of gas state that need introducing, calculate the pressure that gas should reach in the air collector, control system is according to The real time measure air collector internal pressure, to booster and air collector porch on-off valve output signal, control will determine that the blowing agent of quality is collected in the air collector.
On the other hand, the present invention passes through two or more air collectors and controls between air collector, on-off valve between the gas injection port on air collector and the adapted to injection system, repeatedly the blowing agent of certain mass is introduced macromolecule melt respectively, retreat while plastifying with injection screw so well, fusion time reduces to be complementary gradually, and can be according to the relative displacement of injection screw in machine barrel, control system control is between air collector, the break-make of on-off valve is constantly and the time between the gas injection port on air collector and the adapted to injection system, the introducing amount of blowing agent and the plastics capacity of screw rod are complementary, thereby form uniform macromolecule melt/blowing agent homogeneous system, obtain the uniform high-quality foaming product of abscess.
In addition, can change the volume of air collector, the pressure in the air collector easily, make blowing agent drawing-in system of the present invention can adapt to the injection machine of different size.
The present invention be advantageous in that in an injection cycle gas collection process for once, like this to the corresponding reduction that requires of the dynamic response index control accuracy of booster, on-off valve response time, thereby the manufacturing cost of blowing agent drawing-in system of the present invention is reduced, be convenient to suitability for industrialized production.
Simplicity of design of the present invention, easy to operate, cost is lower, is convenient to realize suitability for industrialized production, is fit to all size injection machine.
Description of drawings
Fig. 1 is the repeatedly exemplary illustration of a technical scheme of drawing-in system of discontinuous blowing agent of the present invention;
Fig. 2 is the repeatedly example explanation of another technical scheme of drawing-in system of discontinuous blowing agent of the present invention;
Fig. 3 is embodiment 1 a sample photo;
Fig. 4 is the comparative example photo.
The specific embodiment
The invention will be further described below in conjunction with accompanying drawing:
The pipe-line system that the present invention includes a source of the gas, a blowing agent inlet and be connected with blowing agent inlet fluid with source of the gas.A gas booster is installed, at least two above air collectors, three or three above on-off valves in this pipe-line system.On each air collector of this pipe-line system pressure measuring element is installed, also comprise a control system in addition, this control system can be accepted the signal from processing of high molecular material equipment, and according to the volume of processing needs (a blowing agent quality that the production cycle domestic demand adds) and air collector, calculate the pressure in the air collector, control the action of gas booster simultaneously, adapt with the processing of high molecular material process, output signal control is opened and/or the closure set gas tank enters the mouth and/or the stop valve of outlet, thereby accurate control and an injection cycle inner control of realizing the blowing agent injection rate determine that the blowing agent of quality repeatedly injects.
1 describe technical solution of the present invention in detail in conjunction with the accompanying drawings.With a kind of discontinuous blowing agent among the present invention repeatedly drawing-in system be connected with adapted to injection system 34.Discontinuous foaming agent control lead-in system of the present invention comprises the source of the gas 1 that contains blowing agent, a pipeline 3 that is positioned at the gas injection port 2 on the discontinuous processing of high molecular material device and connects source of the gas 1 outlet and gas injection port 2 fluids.On pipeline 3, booster 6 with entrance and exit is installed, one has inlet 11 and outlet 12 and has the air collector 7 of definite volume, the inlet 11 of air collector 7 is connected with the outlet of booster 6, on the connecting pipeline of the inlet of the outlet of booster 6 and air collector 7 on-off valve 8 is installed.Air collector 9 with entrance and exit, the inlet of air collector 9 is connected by the outlet of on-off valve 10 with air collector 7, and the downstream of air collector 9 outlet is equipped with on-off valve 15, and on-off valve 15 is connected with blowing agent inlet 2 on the injection moulding machine barrel.
Contain physical blowing agent in the source of the gas 1, as normally used nitrogen, carbon dioxide etc., usually source of the gas 1 has larger volume and is used to store a large amount of blowing agents and uses for the foam production process.On pipeline 3, a pressure regulatory element and a pressure test element that is connected with source of the gas 1 outlet optionally is installed, the inlet of booster 6 optionally is connected with the pressure measuring element fluid, according to needs of production, the pressure regulatory element in manual adjustments source of the gas 1 exit, make the pipeline inner pressure of booster 6 inlet upstreams be stabilized in certain force value, thereby guarantee that the booster inlet pressure is stable, improve the booster job stability, make things convenient for the stable normal operation of closed-loop control booster.In some technical schemes, also pressure regulatory element and pressure measuring element can be installed on the pipeline 3.
On-off valve 8, on-off valve 10 and on-off valve 15 can receive the output signal from control system 21, under a kind of state (when being communicated with) allow fluid, comprise that pressurization gas, liquid gas or supercritical fluid flow through therefrom, and (when disconnecting) stops these fluids any device by the there under another kind of state.Suitably the valve of type comprises pneumatic operated valve, magnetic valve, hydraulic valve, guiding valve or other equivalent valve.In some cases, valve 8,10 and 15 may be a same type, and valve may be dissimilar in other cases.
Another technical scheme of the present invention, as shown in Figure 2,3 air collectors that on pipe-line system 3, are installed in series, 4 on-off valves, on-off valve 17 is installed as far as possible near the blowing agent inlet 2 on the injection moulding machine barrel.The volume sum minimum of air collector 7, air collector 9 and air collector 16 is fit to greater than 25ml greater than 20ml, and in some technical schemes, the volume of three air collectors can equate; In other technical schemes, the volume of three air collectors can be unequal, usually the restriction first dosage blowing agent is (promptly in an injection cycle, at first inject the blowing agent of the doses of injection machine inner macromolecule melt) the volume maximum of air collector 16, limit the volume minimum of the air collector 7 of the 3rd dosage blowing agent, the volume of air collector 9 that limits the second dosage blowing agent is greater than the volume of air collector 7, but less than the volume of air collector 16.At the optional position of air collector 16 setting pressure measuring cell 13, the pressure signal that pressure measuring element 13 is measured can be used as input signal input control system 21.
The discontinuous blowing agent of the present invention repeatedly drawing-in system comprises a control system 21, control system 21 can be accepted the signal from adapted to injection system 34, comprise near the pressure signal the gas injection port 2, screw position and motor message etc. also can be accepted the signal of artificial input.Control system 21 can be according to input signal simultaneously, after the calculating, respectively to booster 6, on-off valve 8, on-off valve 10, on-off valve 15 or on-off valve 17 output signals, control the motion of booster 6 and the connection or the cut-out of on-off valve 8, on-off valve 10, on-off valve 15 or on-off valve 17 respectively, thereby realize the introducing dosage of blowing agent, and repeatedly introduce according to screw position.
In the blowing agent drawing-in system shown in the accompanying drawing 1 of the present invention, the pipe-line system that on-off valve 8 and on-off valve 15 are surrounded (this moment on-off valve 10 open), comprise gather the blowing agent of determining quality in air collector 7 and the air collector 9 after, on-off valve 8 is closed.The blowing agent of determining quality is meant the pressure differential according to gas pressure in the air collector and extrusion barrel interpolymer melt, can introduce the quality of the blowing agent in the extrusion barrel, and it be according to the foaming dosage of processing needs required introducing in an injection cycle.
In the blowing agent drawing-in system shown in the accompanying drawing 2 of the present invention, the pipe-line system that on-off valve 8 and on-off valve 17 are surrounded (this moment, on-off valve 10 and on-off valve 15 were opened), after comprising the blowing agent that gathers definite quality in air collector 7, air collector 9 and the air collector 16, on-off valve 8 is closed.The blowing agent of determining quality is meant the pressure differential according to gas pressure in the air collector and extrusion barrel interpolymer melt, can introduce the quality of the blowing agent in the extrusion barrel, and it be according to the foaming dosage of processing needs required introducing in an injection cycle.
Adapted to injection system 34 can be technical known any suitable type, in the illustrative technique scheme, adapted to injection system includes extruding machine 30 and injection mold system 35, extruding machine 30 comprises machine barrel 31, is installed in the screw rod 32 in the machine barrel, screw rod 32 can rotate with downstream and move axially, and the material that is collected in the barrel of screw rod downstream that plasticizing is good is injected into mould 35.The material plasticizing flowing space 33 that machine barrel and screw rod are formed, macromolecular material rotation downstream by screw rod during the fusion cycle of circulation is carried in this space.
The discontinuous blowing agent of the present invention repeatedly drawing-in system method that blowing agent is repeatedly introduced injection machine inner macromolecule material melt comprises:
1) close the on-off valve contiguous with gas injection port, open other all on-off valves, 1 pair of all air collector of source of the gas carry out pneumatic compression;
2) when the pressure in the air collector reaches setting value, close other all on-off valves; This setting value is higher than melt back pressure 1-50MPa in the injection machine, is fit to be higher than 5-30MPa, the most suitable 10-20MPa that is higher than.
3) screw in injection molding machine begins the rotation plasticizing, plasticizing edge, screw rod limit moves axially, control system is according to the displacement of screw rod in machine barrel, in whole spiro rod plasticizing stroke, can control repeatedly open and/or the closure set gas tank between on-off valve, the blowing agent in the air collector is introduced in the macromolecular material melt in the injection machine by control repeatedly.
Starting point a typical moulding cyclc, screw rod 32 is positioned at the downstream end of machine barrel 31, and screw rod 32 beginnings are rotated in machine barrel 31 so that plasticizing macromolecular material and downstream are carried, in a fusion cycle, screw rod 32 is called the plasticizing stroke along the distance that machine barrel 31 retreats.Screw rod 32 begins to rotate to and retreats 1%-50% plasticizing stroke, more suitable 3%-20% plasticizing stroke, when optimum 5%-10% plastifies stroke, control system 21 output signals are closed on-off valve 10, open on-off valve 15, blowing agent in the air collector 9 enters in the macromolecular material melt in the injection machine by blowing agent inlet 2, when the pressure in the air collector equates with melt pressure in the injection machine, close on-off valve 15, and open on-off valve 10, blowing agent in the air collector 7 diffuses into air collector 9, and reaches balance very soon; When extrusion screw 32 retreats into 10%-70% plasticizing stroke along machine barrel 31, be fit to 15%-50% plasticizing stroke, when the most suitable 20%-40% plastifies stroke, control on-off valve 10 is closed for the 2nd time, on-off valve 15 is opened for the second time, blowing agent in the air collector 9 enters in the macromolecule melt in the injection machine by the blowing agent inlet for the second time, when the pressure in the air collector 9 equates with melt pressure in the injection machine, close on-off valve 15, and open on-off valve 10, blowing agent in the air collector 7 diffuses into air collector 9, and reaches balance very soon; When extrusion screw 32 retreats into 30%-95% plasticizing stroke along machine barrel 31, the more suitable 40%-80% plasticizing stroke that retreats into, the most suitable when retreating into 50-70% plasticizing stroke, control on-off valve 15 is opened for the third time, blowing agent in air collector 7 and the air collector 9 is introduced in the interior macromolecule melt of injection machine by the blowing agent inlet, repeatedly injects melt in the injection machine thereby be implemented in the interior blowing agent with certain mass of an injection cycle.
Blowing agent of the present invention is another technical scheme of introducing method repeatedly, as shown in Figure 2, starting point a moulding cyclc, screw rod 32 is positioned at the downstream end of machine barrel 31, the motion of control system 21 control boosters 6 will select the blowing agent of dosage to be limited in the definite pipe-line system of on-off valve 8 and on-off valve 17 in advance, comprise air collector 7, air collector 9 and air collector 16, select of the motion of the blowing agent of dosage according to control system 21 control boosters 6, make the gas pressure in the air collector be higher than melt back pressure 1-50MPa in the injection machine, be fit to be higher than 5-30MPa, the most suitable 10-20MPa that is higher than, after gas pressure in the air collector reaches needed value, control system control on-off valve 8, on-off valve 10, on-off valve 15 and on-off valve 17 are in closed condition.Rotation is so that plasticizing macromolecular material and downstream are carried in machine barrel 31 in screw rod 32 beginnings, and in a fusion cycle, screw rod 32 is called the plasticizing stroke along the distance that machine barrel 31 retreats.Screw rod 32 begins to rotate to and retreats 1%-50% plasticizing stroke, more suitable 3%-20% plasticizing stroke, when optimum 5%-10% plastifies stroke, control system 21 output signals are opened on-off valve 17, blowing agent in the air collector 16 enters in the macromolecular material melt in the injection machine, when the pressure in the air collector equates with melt pressure in the injection machine by blowing agent inlet 2; When extrusion screw 32 retreats into 10%-70% plasticizing stroke along machine barrel 31, be fit to 15%-50% plasticizing stroke, during the most suitable 20%-40% plasticizing stroke, control on-off valve 15 is opened, and the blowing agent in the air collector 9 enters in the macromolecule melt in the injection machine by the blowing agent inlet; When extrusion screw 32 retreats into 30%-95% plasticizing stroke along machine barrel 31, the more suitable 40%-80% plasticizing stroke that retreats into, the most suitable when retreating into 50-70% plasticizing stroke, control on-off valve 10 is opened, the blowing agent of air collector 7 is introduced in the interior macromolecule melt of injection machine by the blowing agent inlet, repeatedly injects melt in the injection machine thereby be implemented in the interior blowing agent with certain mass of an injection cycle.
4) under the rotation plastication of screw in injection molding machine, repeatedly blowing agent of Zhu Ruing and macromolecule melt are uniformly mixed to form homogeneous phase solution, are transported to the storage cavity of screw front end.
Concrete experiment of the present invention is as follows:
Embodiment 1:
Injection machine T120, screw diameter 36mm, draw ratio is 23.6, on the injection machine machine barrel, offer the blowing agent inlet, by pipeline with the discontinuous blowing agent shown in the accompanying drawing 1 of the present invention repeatedly drawing-in system be connected with injection machine at gas injection port, in the source of the gas 1 is nitrogen, and the volume of air collector 7 is 10ml, and the volume of air collector 9 is 15ml.
Processing materials is an acrylic resin, Yanshan Petrochemical company produces, K8308, MI=2.0g/10min, mould is 150mm * 150mm * 2mm sheet die, each section of injection machine temperature is set at 160 ℃ respectively from the charge door to the nozzle, and 180 ℃, 200 ℃, 210 ℃, 210 ℃, the melt back pressure set is 20MPa, and rotating speed is 80rpm during spiro rod plasticizing; Each technological parameter of injection moulding process is as shown in table 1, and gas injection rate represents to inject in the fusion cycle ratio of blowing agent quality and the melt quality of plasticizing.The N of Zhu Ruing as required
2The pressure set points that quality, control system calculate in the air collector is 25MPa, and in an injection cycle, it is as follows that blowing agent is introduced concrete steps:
Close the on-off valve 15 contiguous with gas injection port, open on-off valve 8 and on-off valve 10, source of the gas 1 is by 6 pairs of all air collectors 7 of booster and air collector 9 25MPa that carries out pneumatic compression, close on-off valve 8, screw in injection molding machine begins rotation plasticizing, and rotation plasticizing limit, screw rod limit retreats, when screw rod retreat into the plasticizing stroke 10% the time, open on-off valve 15, the blowing agent in the air collector 9 enters in the plastic melt in the injection machine by inlet 2; When blowing agent pressure in the air collector 9 equates with injection machine fused mass pressure, close on-off valve 15, open on-off valve 10, blowing agent in the air collector 7 diffuses in the air collector 9, closing passage valve 10 behind the lasting 0.1s, when screw rod retreat into the plasticizing stroke 30% the time, open for the second time on-off valve 15, blowing agent in the air collector 9 injects in the plastic melt of adapted to injection system, when the blowing agent pressure in the air collector 9 equates with melt pressure in the injection machine, close on-off valve 15, open on-off valve 10, the blowing agents in the air collector 7 diffuse in the air collector 9, when screw rod retreat into the plasticizing stroke 50% the time, open on-off valve 15 for the third time, the blowing agent in air collector 9 and the air collector 7 is introduced in the plastic melt of adapted to injection system.
The screw rod rotation is even with blowing agent and the macromolecular material melt mixed of injecting, form homogeneous phase solution, and homogeneous phase solution carried in the storage cavity of screw head, in storage cavity, store polymer/blowing agent homogeneous phase solution and reach the injection moulding requirement, screw rod stops the rotation, and, obtain the injection foaming goods with in the injection of the homogeneous phase solution in the storage cavity die cavity.
Repeat above frothing injection process 20～50 times, all can obtain the uniform PP injection foaming of abscess goods.
Embodiment 2
Used injection machine, blowing agent is drawing-in system repeatedly, test with macromolecular material with embodiment 1, difference is, the melt back pressure set is 20MPa, the control booster is increased to 30MPa with the pressure in air collector 7 and the air collector 9, the blowing agent injection technology is identical with embodiment 1, difference is, when screw rod rotate back into the plasticizing stroke 30% the time, open for the first time on-off valve 15, realize that gas is introduced for the first time, when screw rod rotates back into plasticizing stroke 50%, open for the second time on-off valve 15, realize that gas is introduced for the second time, when screw rod rotates back into plasticizing stroke 70%, open on-off valve 15 for the third time, realize that gas is introduced for the third time.Screw rod rotation plasticizing and injection process are identical with embodiment 1.
Repeat above frothing injection process 20～50 times, all can obtain the uniform PP injection foaming of abscess goods.
Used injection machine, experiment with macromolecular material with embodiment 1, blowing agent repeatedly drawing-in system as shown in Figure 2, the melt back pressure set is 15MPa, is nitrogen in the source of the gas 1, the volume of air collector 7, air collector 9 and air collector 16 is 10ml.In an injection cycle, it is as follows that blowing agent is repeatedly introduced concrete steps:
Close the on-off valve 17 contiguous with gas injection port, open on-off valve 8, on-off valve 10 and on-off valve 15, source of the gas 1 is by booster 6 pairs of all air collectors 7, air collector 9 and air collectors 16 35MPa that carries out pneumatic compression.Close on-off valve 8, channel valve 10 and on-off valve 15.Screw in injection molding machine begins rotation plasticizing, and rotation plasticizing limit, screw rod limit retreats, when screw rod retreat into the plasticizing stroke 10% the time, open on-off valve 17, the blowing agent in the air collector 16 enters in the plastic melt in the injection machine by inlet 2; When the pressure in the air collector 16 equates with melt pressure in the injection machine, close on-off valve 17, open on-off valve 15 then, on-off valve 15 is closed in the gas counterdiffusion mutually in air collector 9 and the air collector 16 behind the 0.1s; When screw rod rotate back into the plasticizing stroke 30% the time, open for the second time on-off valve 17, the gases in the air collector 16 are introduced in the plastic melt in the injection machine for the second time; When the gas pressure in the air collector 16 equates with melt pressure in the injection machine, close on-off valve 17, open on-off valve 15 then, gas counterdiffusion mutually in air collector 9 and the air collector 16, when spiro rod plasticizing retreat into the plasticizing stroke 50% the time, open on-off valve 17 for the third time, the blowing agents in air collector 9 and the air collector 16 are introduced in the plastic melt in the injection machine for the third time; When the blowing agent pressure in air collector 9 and the air collector 16 equates with plastic melt pressure in the injection machine, close on-off valve 17, open on-off valve 10 then, the gas counterdiffusion mutually that the gas in the air collector 7 and air collector 9, air collector 16 are interior, 0.1s after, close on-off valve 10; When screw rod rotate back into the plasticizing stroke 70% the time, open on-off valve 17 the 4th time, blowing agent in the air collector 9, air collector 16 is by in the plastic melt in the 4th introducing injection machine, when the gas pressure in air collector 9, the air collector 16 equates with the pressure of plastic melt, close on-off valve 17, open on-off valve 10 then, the blowing agent in the air collector 7 diffuses in air collector 9 and the air collector 16; When screw rod rotate back into the plasticizing stroke 90% the time, open on-off valve 17 the 5th time, in the plastic melt in the 5th introducing injection machine of the blowing agent in the air collector.
The screw rod rotation is even with blowing agent and the macromolecular material melt mixed of injecting, form homogeneous phase solution, and homogeneous phase solution carried in the storage cavity of screw head, in storage cavity, store polymer/blowing agent homogeneous phase solution and reach the injection moulding requirement, screw rod stops the rotation, and, obtain the injection foaming goods with in the injection of the homogeneous phase solution in the storage cavity die cavity.
Repeat above frothing injection process 20～50 times, all can obtain the uniform PP injection foaming of abscess goods.
Embodiment 4
Used injection machine, blowing agent is drawing-in system repeatedly, test with macromolecular material with embodiment 3, difference is, the melt back pressure set is 10MPa, the control booster is increased to 40MPa with the pressure in air collector 7 and the air collector 9, the blowing agent injection technology is identical with embodiment 3, difference is, when screw rod rotate back into the plasticizing stroke 5% the time, open for the first time on-off valve 17, realize that gas is introduced for the first time, when screw rod rotates back into plasticizing stroke 10%, open for the second time on-off valve 17, realize that gas is introduced for the second time, when screw rod rotates back into plasticizing stroke 30%, open on-off valve 17 for the third time, realize that gas is introduced for the third time, when screw rod rotates back into plasticizing during stroke 50%, open on-off valve 17 the 4th time, realize that the 4th gas introduces; When screw rod rotate back into the plasticizing stroke 70% the time, open on-off valve 17 the 5th time, realize that the 5th blowing agent introduce, screw rod rotation plasticizing and injection process are identical with embodiment 1.
Repeat above frothing injection process 20～50 times, all can obtain the uniform PP injection foaming of abscess goods.
Comparative example
Used injection machine, blowing agent repeatedly drawing-in system, the test with macromolecular material with embodiment 1, difference is, the melt back pressure set is 20MPa, frothing injection in the cycle on-off valve be in open mode always, air collector 7 and air collector 9 mutual fluids are connected.According to the foaming needs pressure in the air collector is increased to 30MPa, when screw rod rotate back into the plasticizing stroke 30% the time, open on-off valve 15, the blowing agent in the air collector is once introduced in the plastic melt in the injection machine, screw rod rotation plasticizing and injection process are identical with embodiment 1.
Repeat above frothing injection process 20～50 times, all can obtain the uniform PP injection foaming of abscess goods.
Above embodiment and Comparative Examples gained sample are compared, observe products surface quality, play bulla probability, delamination area size per sample, short the situation of penetrating and carry out grading evaluation, sum up and list in the table 1.
Table 1
Claims (10)
1. discontinuous blowing agent is drawing-in system repeatedly, comprises that one contains the source of the gas (1) of blowing agent, a pipeline (3) and a control system that is positioned at gas injection port (2), connection source of the gas (1) and gas injection port (2) on the injection machine machine barrel; On pipeline (3), be equipped with:
Booster (6) with entrance and exit, the inlet of booster (6) is connected with source of the gas (1), the outlet of booster (6) at least two air collectors that are installed in series, the cumulative volume of each air collector is greater than 20ml;
The outlet of last air collector of series connection is connected with gas injection port (2) pipeline mutually, on the connecting pipeline of between on-off valve is installed;
The inlet of first air collector of series connection is connected with the outlet of booster mutually, on the connecting pipeline of between on-off valve is installed;
Between each air collector of series connection on-off valve is installed also mutually;
With air collector that gas injection port (2) is connected on a pressure measuring element is installed at least, this pressure measuring element can be to the control system output signal;
Booster (6) and each on-off valve all can be accepted the output signal of control system.
2. discontinuous blowing agent according to claim 1 is drawing-in system repeatedly, it is characterized in that: the number of the air collector that described outlet polyphone at booster is installed is 2～10.
3. discontinuous blowing agent according to claim 2 is drawing-in system repeatedly, it is characterized in that: the number of the air collector that described outlet polyphone at booster is installed is 3～5.
4. use the discontinuous blowing agent described in the claim 1 repeatedly drawing-in system blowing agent is repeatedly introduced method in the injection machine inner macromolecule melt, it is characterized in that this method may further comprise the steps:
1) close the on-off valve that is connected with gas injection port, open other all on-off valves, source of the gas carries out pneumatic compression to all air collectors;
2) when the pressure in the air collector reaches greater than injection machine inner macromolecule melt back pressure 1-50MPa, close all on-off valves;
3) screw in injection molding machine begins the rotation plasticizing, plasticizing edge, screw rod limit moves axially, control system is according to the displacement of screw rod in machine barrel, repeatedly open on-off valve between the mutual series connection air collector in whole spiro rod plasticizing stroke inner control, and/or the on-off valve between last air collector and the gas injection port, the blowing agent in the air collector is repeatedly controlled in the macromolecular material melt of introducing in the injection machine like this;
In injection machine, introduce blowing agent at every turn, when the pressure in last air collector equates with melt pressure in the injection machine, the on-off valve of then closing between last air collector and the gas injection port finishes to introduce, open the on-off valve between the air collector then, make blowing agent between each air collector, spread and reach new pressure balance, wait for next time and introducing;
4) under the rotation plastication of screw in injection molding machine, repeatedly blowing agent of Zhu Ruing and macromolecule melt are uniformly mixed to form homogeneous phase solution, are transported to the storage cavity of screw front end.
5. according to claim 4 with the discontinuous method of repeatedly introducing in the injection machine inner macromolecule melt of blowing agent, it is characterized in that: before the plasticizing in step 3) began, the gas pressure in the air collector was greater than injection machine inner macromolecule melt back pressure 5-30MPa.
6. according to claim 4 or 5 described with the discontinuous method of repeatedly introducing in the injection machine inner macromolecule melt of blowing agent, it is characterized in that: before the plasticizing in step 3) began, the gas pressure in the air collector was greater than injection machine inner macromolecule melt back pressure 10-20MPa.
7. according to claim 4 with the discontinuous method of repeatedly introducing in the injection machine inner macromolecule melt of blowing agent, it is characterized in that: the on-off valve of opening in an injection cycle described in the step 3) is introduced the number of times of blowing agent and is no less than 3 times in injection machine.
8. according to claim 4 with the discontinuous method of repeatedly introducing in the injection machine inner macromolecule melt of blowing agent, it is characterized in that: the on-off valve of opening in an injection cycle described in the step 3) is introduced the number of times of blowing agent and is no less than 5 times in injection machine.
9. according to claim 4 blowing agent is repeatedly introduced method in the injection machine inner macromolecule melt, it is characterized in that: when screw rod retreated into the 5%-50% of plasticizing stroke, the on-off valve of opening for the first time between last air collector and the gas injection port was introduced blowing agent in the macromolecule melt in the injection machine in the step 3).
10. according to claim 4 blowing agent is repeatedly introduced method in the injection machine inner macromolecule melt, it is characterized in that: in the step 3) when screw rod retreat into the plasticizing stroke 50-90% the time, open the on-off valve between last air collector and the gas injection port for the last time, in the macromolecule melt in the blowing agent introducing injection machine of final dose in the fusion cycle.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102658620A (en) * | 2012-05-07 | 2012-09-12 | 青岛海信模具有限公司 | Method for improving surface quality of foam molded plastic part |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4115491A (en) * | 1975-07-25 | 1978-09-19 | Robert Hanning | Method of making thermoplastic articles with porous cores |
| CN101392076A (en) * | 2008-10-10 | 2009-03-25 | 常州天晟新材料股份有限公司 | Duprene rubber foamed sheet and preparation method thereof |
| CN101612773A (en) * | 2009-07-24 | 2009-12-30 | 北京化工大学 | Discontinuous foaming agent control lead-in system and method |
-
2010
- 2010-10-29 CN CN2010105323364A patent/CN102059767A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4115491A (en) * | 1975-07-25 | 1978-09-19 | Robert Hanning | Method of making thermoplastic articles with porous cores |
| CN101392076A (en) * | 2008-10-10 | 2009-03-25 | 常州天晟新材料股份有限公司 | Duprene rubber foamed sheet and preparation method thereof |
| CN101612773A (en) * | 2009-07-24 | 2009-12-30 | 北京化工大学 | Discontinuous foaming agent control lead-in system and method |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102658620A (en) * | 2012-05-07 | 2012-09-12 | 青岛海信模具有限公司 | Method for improving surface quality of foam molded plastic part |
| CN102658620B (en) * | 2012-05-07 | 2014-03-26 | 青岛海信模具有限公司 | Method for improving surface quality of foam molded plastic part |
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Application publication date: 20110518 |