Casting piece forming device for thin film production

Abstract

The invention relates to the technical field of film casting piece forming, in particular to a casting piece forming device for film production, which comprises a die head, an air knife and a chilling roller, a shell is fixedly mounted on the chilling roller, a copper conducting layer is arranged in the chilling roller, and a rapid cooling mechanism is arranged at the bottom end of the shell and is used for spraying water mist with charges to the chilling roller; and a pulling mechanism is arranged in the shell and is used for pulling the water mist. The copper conducting layer is arranged in the chilling roller to be matched with the rapid cooling mechanism and the extraction mechanism, air cooling and water cooling are efficiently combined, the problems that the efficiency of air cooling is insufficient and surface defects are likely to be caused by water cooling can be avoided, and the stability and uniformity of a thin film casting piece during cooling can be effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of film casting sheet forming, in particular to a casting sheet forming device for film production. BACKGROUND

[0002] The casting sheet machine is used for film production, which needs to melt the material into a molten body. Under the push of the metering pump pressure, the film raw material of the molten body is forced to pass through the long-shaped port of the die head, and under the action of external force (static electricity, airflow, vacuum), the molten body is quickly attached to the surface of the chill roller, so that the chill roller cools and crystallizes the raw material into a solid sheet. After extrusion, the film needs to be tightly attached to the chill roller to prevent air from entering between the film and the roller, causing uneven cooling of the film in some areas, and thus preventing product quality defects caused by unstable product quality.

[0003] When the casting sheet machine is forming, multi-stage cooling is used, and common methods include water tank external cooling, multi-roller cooling, and air external cooling. The water tank external cooling method needs to immerse the casting sheet into the water tank to achieve rapid cooling of the casting sheet by using the high specific heat capacity of water. However, since the water cooling method is through direct contact between the casting sheet and water, water will remain on the surface of the casting sheet when it is separated from the water, forming water marks. At the same time, the high surface tension of water will cause uneven shrinkage of the casting sheet surface, resulting in poor surface quality and large fluctuations in mechanical properties of the produced casting sheet, which is completely unsuitable for high-end films such as optical films and electronic substrates.

[0004] In view of this, we propose a casting sheet forming device for film production. SUMMARY

[0005] The purpose of the present application is to provide a casting sheet forming device for film production, which solves the problems raised in the background art.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme: A casting sheet forming device for film production, comprising a die head, an air knife, and a chill roller, wherein the chill roller is fixedly installed with an outer shell, the chill roller is provided with a copper conductive layer, the bottom end of the outer shell is provided with a rapid cooling mechanism for spraying water mist with electric charge to the chill roller; the outer shell is provided with an extraction mechanism for extracting the water mist.

[0007] Preferably, the rapid cooling mechanism comprises an atomization generator, the atomization generator is provided with an electrostatic atomization nozzle, the electrostatic atomization nozzle is fixedly connected with a mixing box, one end of the mixing box is fixedly connected with an air inlet pipe.

[0008] Preferably, the other end of the mixing box is fixedly connected with an air outlet pipe, a plurality of connecting pipes are connected to the air outlet pipe, a jet pipe is fixedly connected to the top end of the connecting pipe, and the jet pipe is fixedly connected with the outer shell Preferably, one end of the copper conductive layer is connected with a direct current power supply, and the other end of the copper conductive layer is grounded.

[0009] Preferably, the air injection pipe comprises an air diffuser pipe one, the air diffuser pipe one is fixedly connected between the connecting pipe, the air diffuser pipe one is fixedly connected with an air diffuser pipe two at the top end, the air diffuser pipe two is fixedly installed with an arc-shaped air equalizing plate inside, and the air diffuser pipe two is fixedly installed with a straight air equalizing plate inside at the top end position.

[0010] Preferably, the air diffuser pipe two is provided with a flow guide plate on the inner side wall, the air diffuser pipe one is fixedly installed with a liquid outlet pipe at the top end of the side portion, and the flow guide plate is connected with the top end of the liquid outlet pipe.

[0011] Preferably, the separation mechanism comprises two baffles, the two baffles are symmetrically fixedly installed on the inner wall of the shell, the baffle and the center of the chill roller are on the same horizontal line, and the baffle is fixedly installed with a baffle between the inner bottom end of the shell.

[0012] Preferably, the two baffles are provided with air ducts, the air ducts are fixedly connected with air pumps through pipelines, the bottom end of one baffle is provided with a jet port one, and the side of the chill roller of the baffle is provided with a jet port two; the bottom end of the other baffle is provided with an air inlet one, and the side of the chill roller of the baffle is provided with an air inlet two.

[0013] Preferably, the baffle provided with the jet port one is arranged close to the air knife position, and the opening of the jet port two is inclined downward.

[0014] Preferably, the opening of the air inlet two is inclined upward, and the openings of the jet port one and the air inlet one are consistent with the inclination angle of the baffle.

[0015] By the above technical scheme, the casting forming device for film production provided by the application at least has the following beneficial effects: (1) By arranging the copper conductive layer in the chill roller, cooperating with the rapid cooling mechanism and the separation mechanism, the air cooling and water cooling are combined efficiently, the problems of insufficient air cooling efficiency and surface defects caused by water cooling can be avoided, and the stability and uniformity of the film casting piece during cooling are effectively improved.

[0016] (2), the present application sets up copper conductive layer in chilling roll and connects direct current power supply, makes chilling roll surface carry stable electric charge; simultaneously, set up quick cooling mechanism, quick cooling mechanism can spray out atomized liquid drop with same kind of electric charge. Because same kind of electric charge repel each other, make atomized liquid drop not impact spread when approaching casting sheet surface, but carry out non-contact type bounce above and evaporate heat rapidly. Thus realize that can utilize the high efficiency cooling capacity of liquid drop evaporation, also can avoid liquid drop and casting sheet contact, and then avoid the casting sheet surface quality problem of conventional water cooling.

[0017] (3), the present application sets up quick cooling mechanism cooperation with extraction mechanism, and through the baffle and the baffle in the shell inside for casting sheet cooling constructs a closed controllable environment. On the one hand, utilize dry gas as the carrier of atomized liquid drop, and through mixing box accurate control air humidity, ensure the stability of cooling process. On the other hand, extraction mechanism forms directional, stable air flow barrier and circulation on both sides of chilling roll, can effectively prevent atomized liquid drop upward escape and interfere with casting sheet attachment and subsequent process, also can extract the moisture after evaporation in time, maintain the constancy of environmental parameter, to ensure the uniformity and consistency of casting sheet from attachment to cooling whole process, greatly reduce product defects. BRIEF DESCRIPTION OF DRAWINGS

[0018] The drawings described herein are used to provide further understanding of the present application, and constitute a part of the present application: Figure 1 It is the structural schematic diagram of the present application; Figure 2 It is the structural schematic diagram of the quick cooling mechanism of the present application; Figure 3 It is the structure schematic diagram of atomization generator and its connecting part of the present application; Figure 4 It is the cross section structure schematic of the connecting pipe and the air injection pipe of the present application Figure 1 ; Figure 5 It is the cross section structure schematic of the connecting pipe and the air injection pipe of the present application Figure 2 ; Figure 6 It is the structure schematic diagram of the extraction mechanism of the present application.

[0019] In the drawing: 1, die head;2, air knife;3, chilling roll;4, cooling roll;5, shell;6, quick cooling mechanism;7, extraction mechanism;8, copper conductive layer; 61, atomization generator;62, electrostatic atomization nozzle;63, mixing box;64, air inlet pipe;65, air outlet pipe;66, connecting pipe;67, air injection pipe;68, arc-shaped air uniform plate;69, straight air uniform plate;671, air expansion pipe one;672, air expansion pipe two;673, drainage plate;674, liquid outlet pipe; 71, baffle; 72, partition; 73, air duct; 74, air jet one; 75, air jet two; 76, air inlet one; 77, air inlet two. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0021] Referring to Figures 1-6 A cast sheet forming device for film production includes a shell 5 for providing protection for the entire cast sheet production process and facilitating the provision of an inert gas environment for film production and the stabilization of cast sheet production. A die head 1 is fixedly installed at the top end of the shell 5 for uniform discharge of molten material. A chill roll 3 is rotatably installed at the middle position inside the shell 5 for cooling and setting the cast sheet. An air knife 2 is arranged between the die head 1 and the chill roll 3 inside the shell 5 for spraying a uniform, high-speed, linear air flow to "blow" or "press" the soft melt curtain to the surface of the ice-cold chill roll 3, and also to blow away the gas possibly entrained between the melt and the chill roll 3 to prevent the formation of surface defects such as "bubbles" or "spots". A cooling roll 4 is rotatably installed at a position away from the air knife 2 inside the shell 5 for increasing the contact time of the cast sheet on the chill roll 3 and for secondary auxiliary cooling of the cast sheet.

[0022] Referring to Figure 1 The chill roll 3 is provided with a copper conductive layer 8. A rapid cooling mechanism 6 is arranged at the bottom end of the shell 5. One end of the copper conductive layer 8 is connected to a direct current power supply, and the other end is grounded. The surface of the chill roll 3 is maintained in a negatively charged state through electrostatic induction. The rapid cooling mechanism 6 generates atomized liquid droplets with negative charges, which are diluted by the air flow, so that the atomized gas with negative charges and stable humidity impacts the surface of the cast sheet. Through the repulsion of the same charges and the impact of the air flow, the atomized liquid droplets can be close to the cast sheet for heat radiation and convection, thereby cooling the cast sheet, and the atomized liquid droplets are prevented from contacting the surface of the cast sheet to avoid the impact of the liquid droplets on the cast sheet.

[0023] Referring to Figure 2 The rapid cooling mechanism 6 includes an atomization generator 61. An electrostatic atomization nozzle 62 is arranged on the atomization generator 61. An electrostatic generator is connected to the electrostatic atomization nozzle 62. A positive ring electrode of the electrostatic generator is fixedly installed in the electrostatic atomization nozzle 62. The atomized liquid droplets generated by the atomization generator 61 carry negative charges under the action of electrostatic induction when passing through the electrostatic atomization nozzle 62.

[0024] Please refer to Figure 3 , the top of the electrostatic atomization nozzle 62 is fixedly installed in the mixing box 63, one end of the mixing box 63 is fixedly connected with the air inlet pipe 64, the gas flow into the air inlet pipe 64 is nitrogen or clean and dry air, and the humidity of the gas with atomized droplets in the mixing box 63 can be controlled by controlling the air volume of the air inlet pipe 64 and the atomization efficiency of the atomization generator 61, and meanwhile, since the atomized droplets all have the same charge, the atomized droplets are prevented from gathering to form large droplets to affect the uniformity of the atomized droplets.

[0025] In the embodiment, the other end of the mixing box 63 is fixedly connected with the air outlet pipe 65, a plurality of connecting pipes 66 are connected to the air outlet pipe 65, the top of each connecting pipe 66 is fixedly connected with a jet pipe 67, and the jet pipe 67 is fixedly connected with the bottom end of the shell 5. The atomized droplet gas flow with stable concentration in the mixing box 63 can be dispersed into each jet pipe 67 through the air outlet pipe 65 and the connecting pipes 66 for spraying, and according to the different distances of the jet pipes 67 from the mixing box 63, the spraying amount and speed of the jet pipes 67 gradually decrease along the air outlet pipe 65. The jet pipe 67 is located below the chilling roller 3, so that the sprayed gas carrying the atomized droplets impacts the casting sheet on the chilling roller 3, thereby realizing heat exchange for cooling.

[0026] It should be noted that a valve is arranged on each connecting pipe 66 for controlling the outflow amount and speed of the gas flow to adapt to different casting sheets and avoid that the impact between the atomized droplets carried by the gas flow on the casting sheet causes surface defects of the casting sheet due to too fast gas flow speed, and also avoid that the gas flow is too slow to cause the droplets to be too far away from the casting sheet to affect the heat exchange efficiency.

[0027] Please refer to Figure 4 and Figure 5 , the jet pipe 67 comprises an air diffuser pipe one 671 fixedly connected between the connecting pipe 66 and the air diffuser pipe two 672 fixedly connected with the top of the air diffuser pipe one 671, the opening angle of the air diffuser pipe one 671 is smaller than that of the air diffuser pipe two 672, the air flow is preliminarily diffused by the air diffuser pipe one 671 to enhance the preliminary diffusion speed, the air diffuser pipe two 672 enhances the diffusion range to balance the diffusion speed and diffusion range, so that the gas flow carrying the atomized droplets can be quickly and uniformly diffused.

[0028] In addition, the arc-shaped air equalizing plate 68 is fixedly installed in the air diffuser pipe two 672, a plurality of uniformly sized through holes are formed in the arc-shaped air equalizing plate 68, and the through hole density gradually increases from the middle to the two sides. On the one hand, the atomized liquid droplets are screened, and on the other hand, the atomized liquid droplets are forced to disperse uniformly, thereby improving the uniformity of the atomized liquid droplets in the air diffuser pipe two 672. The straight air equalizing plate 69 is fixedly installed at the top end inside the air diffuser pipe two 672, and a plurality of through holes are uniformly distributed in the straight air equalizing plate 69. The straight air equalizing plate 69 is used for screening and equalizing the atomized liquid droplets, so that the uniformity of the sprayed atomized liquid droplets is higher, thereby improving the uniformity and stability during cooling.

[0029] It is worth noting that the inner side wall of the air diffuser pipe two 672 is provided with a drainage plate 673. Since the air diffuser pipe two 672 has a structure of constant width and gradually increasing length, the airflow always has an impact on the horizontally connected side when diffusing. For the inclined side, the impact of the airflow is smaller, and there is a certain dead angle. This makes the atomized liquid droplets blocked by the arc-shaped air equalizing plate 68 can gather and flow downward along the drainage plate 673 under the action of gravity. The air diffuser pipe one 671 is fixedly installed with a liquid outlet pipe 674 at the top end of the side portion. The bottom end of the drainage plate 673 is connected to the top end of the liquid outlet pipe 674. The collected liquid droplets enter the liquid outlet pipe 674 and are collected, avoiding the aggregation of liquid droplets affecting the equalization effect.

[0030] Please refer to Figure 1 and Figure 6 The separation mechanism 7 includes two partitions 72, which are fixedly installed on the inner wall of the shell 5 and are symmetrical. The center of the partition 72 is on the same horizontal line as the center of the chilling roller 3. The shell 5 is divided into upper and lower parts by the partition 72. The upper part is used for the production, attachment and transfer of the cast sheet, and the lower part is used for the rapid cooling and forming of the two sides of the cast sheet.

[0031] In this embodiment, the baffle 71 is fixedly installed between the partition 72 and the bottom end of the shell 5. The baffle 71 is inclined to reduce the space below the shell 5, reduce the airflow dead angle, and avoid gas and atomized liquid droplets from being retained.

[0032] Especially explained, the baffle 72 close to the air knife 2: the baffle 72 is provided with an air duct 73, the air duct 73 is fixedly connected with an air pump through a pipeline, and the air pump can uniformly output air flow into the air duct 73. The baffle 72 is provided with a gas injection port one 74 at the bottom end, and the opening angle of the gas injection port one 74 is consistent with the inclination angle of the baffle 71, so that the air flow sprayed from the gas injection port one 74 can move downward along the baffle 71, and the air flow and the atomized liquid droplets on the baffle 71 are transported. There is still a certain spacing between the closest gas injection port one 74 and the gas injection pipe 67, so that the air flow sprayed from the gas injection port one 74 has little effect on the air flow sprayed from the gas injection pipe 67. The baffle 72 is provided with a gas injection port two 75 close to the chill roller 3, and the opening of the gas injection port two 75 is inclined downward. The air flow sprayed from the gas injection port two 75 plays a role in isolating the gap between the baffle 72 and the chill roller 3, avoiding the atomized liquid droplets from escaping to the upper side of the baffle 72, and the air flow sprayed from the gas injection port two 75 also plays a role in assisting the adhesion of the cast strip and the chill roller 3.

[0033] The baffle 72 away from the air knife 2: the baffle 72 is provided with an air duct 73, the air duct 73 is fixedly connected with an air pump through a pipeline, and the air pump can uniformly output air flow into the air duct 73. The baffle 72 is provided with a gas injection port one 74 at the bottom end, and the opening angle of the gas injection port one 74 is consistent with the inclination angle of the baffle 71, so that the air flow sprayed from the gas injection port one 74 can move downward along the baffle 71, and the air flow and the atomized liquid droplets on the baffle 71 are transported. There is still a certain spacing between the closest gas injection port one 74 and the gas injection pipe 67, so that the air flow sprayed from the gas injection port one 74 has little effect on the air flow sprayed from the gas injection pipe 67. The baffle 72 is provided with a gas injection port two 75 close to the chill roller 3, and the opening of the gas injection port two 75 is inclined downward. The air flow sprayed from the gas injection port two 75 plays a role in isolating the gap between the baffle 72 and the chill roller 3, avoiding the atomized liquid droplets from escaping to the upper side of the baffle 72, and the air flow sprayed from the gas injection port two 75 also plays a role in assisting the adhesion of the cast strip and the chill roller 3.

[0034] A cast strip forming device for thin film production, and the working principle is: Start the pump, the direct current power supply, the static electricity generator and the atomization generator 61. The atomization generator 61 works to convert water into atomized liquid droplets by the electrostatic atomization nozzle 62 and deliver the atomized liquid droplets into the mixing box 63. During the atomization process, the static electricity generator works to make the atomized liquid droplets converted by the electrostatic atomization nozzle 62 carry negative electricity. Then, nitrogen or clean and dry air is introduced into the electrostatic atomization nozzle 62 through the air inlet pipe 64, so that the air flow carrying the atomized liquid droplets with negative electricity in a certain humidity range enters the gas injection pipe 67 through the air outlet pipe 65 and the connecting pipe 66. The atomized liquid droplets can be uniformly and efficiently sprayed onto the surface of the cast strip through the double distribution of the arc-shaped air distribution plate 68 and the straight air distribution plate 69. At the same time, since multiple gas injection pipes 67 share one air outlet pipe 65, the air flow and the air flow speed of the gas injection pipes 67 close to the mixing box 63 gradually decrease, which is consistent with the trend that the cast strip gradually approaches the gas injection pipes 67.

[0035] Due to the direct current power supply, the chilling roller 3 carries negative electricity through the copper conductive layer 8, and the gas sprayed by the air jet pipe 67 carries the atomized liquid droplets to impact the casting sheet on the chilling roller 3, so as to realize heat exchange and cooling. At the same time, due to the same charge carried by the atomized liquid droplets and the chilling roller 3, the atomized liquid droplets and the casting sheet surface realize non-contact cooling under the repulsion of the charge force.

[0036] The air pump works, so that the air outlet 74 and the air inlet 76 work, so that the overall flow direction of the atomized liquid droplets and the gas is consistent with the moving direction of the casting sheet, and the air flow and the air flow speed of the air jet pipe 67 gradually decrease from close to the mixing box 63 to far away from the mixing box 63, so that the overall atomized liquid droplets distribution under the casting sheet is more uniform, and the atomized liquid droplets will not stay on the casting sheet, which can effectively enhance the cooling effect. At the same time, the air outlet 75 and the air inlet 77 work, so that the upper and lower spaces of the partition plate 72 are separated by the gas, and the phenomenon of atomized liquid droplets escaping will not appear, which avoids the influence of atomized liquid droplets on the early adhesion of the casting sheet and the cooling of the later cooling roller 4.

[0037] It should be noted that, in this text, relational terms such as first and second are used merely to distinguish one entity or action from another, without necessarily requiring or implying any such actual relationship or order between such entities or actions. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment.

[0038] Although the embodiments of the present application have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirits of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A casting sheet forming apparatus for thin film production, comprising a die head (1), an air knife (2), and a chilling roller (3), characterized in that: A housing (5) is fixedly installed on the cooling roller (3). A copper conductive layer (8) is provided inside the cooling roller (3). A rapid cooling mechanism (6) is provided at the bottom of the housing (5) for spraying water mist with charge onto the cooling roller (3). An extraction mechanism (7) is provided inside the housing (5) for extracting the water mist.

2. The casting sheet forming apparatus for thin film production according to claim 1, characterized in that: The rapid cooling mechanism (6) includes an atomizer (61), an electrostatic atomizing nozzle (62) is provided on the atomizer (61), a mixing box (63) is fixedly connected to the electrostatic atomizing nozzle (62), and an air inlet pipe (64) is fixedly connected to one end of the mixing box (63).

3. The casting sheet forming apparatus for thin film production according to claim 2, characterized in that: The other end of the mixing box (63) is fixedly connected to an air outlet pipe (65), and multiple connecting pipes (66) are connected to the air outlet pipe (65). The top end of the connecting pipe (66) is fixedly connected to an air jet pipe (67), and the air jet pipe (67) is fixedly connected to the outer shell (5).

4. The casting sheet forming apparatus for thin film production according to claim 2, characterized in that: Preferably, one end of the copper conductive layer (8) is connected to a DC power supply, and the other end of the copper conductive layer (8) is grounded.

5. The casting sheet forming apparatus for thin film production according to claim 3, characterized in that: The jet pipe (67) includes an air expansion pipe (671), which is fixedly connected to a connecting pipe (66). An air expansion pipe (672) is fixedly connected to the top of the air expansion pipe (671). An arc-shaped air distribution plate (68) is fixedly installed inside the air expansion pipe (672), and a straight air distribution plate (69) is fixedly installed inside the air expansion pipe (672) near the top.

6. The casting sheet forming apparatus for thin film production according to claim 5, characterized in that: The inner side wall of the second air expansion pipe (672) is provided with a diversion plate (673), and the top of the side of the first air expansion pipe (671) is fixedly installed with a liquid outlet pipe (674). The bottom end of the diversion plate (673) is connected to the top end of the liquid outlet pipe (674).

7. The casting sheet forming apparatus for thin film production according to claim 1, characterized in that: The extraction mechanism (7) includes two partitions (72), which are symmetrically fixedly installed on the inner wall of the outer shell (5). The center of the partitions (72) and the center of the cooling roller (3) are on the same horizontal line. A baffle (71) is fixedly installed between the partitions (72) and the bottom of the inner wall of the outer shell (5).

8. A casting sheet forming apparatus for thin film production according to claim 7, characterized in that: Both partitions (72) are provided with air ducts (73), and air pumps are fixedly connected to the air ducts (73) through pipes. One partition (72) has a jet nozzle (74) at the bottom end and a jet nozzle (75) on the side of the partition (72) near the cooling roller (3). The other partition (72) has an air inlet (76) at the bottom end and an air inlet (77) on the side of the partition (72) near the cooling roller (3).

9. A casting sheet forming apparatus for thin film production according to claim 8, characterized in that: The partition (72) has a jet nozzle (74) located near the air knife (2), and the jet nozzle (75) has an opening that is tilted downward.

10. A casting sheet forming apparatus for thin film production according to claim 9, characterized in that: The opening of the second air inlet (77) is tilted upward, and the openings of the first jet inlet (74) and the first air inlet (76) are both at the same tilt angle as the baffle (71).

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