CN115447050A - Film casting sheet forming cooling device and technological method - Google Patents

Abstract

The invention discloses a film cast sheet molding cooling device and a process method, which comprises a die head, a chilling component, a cooling component and an adjusting component, wherein the chilling component comprises a hollow chilling roller and a chilling water circulating system communicated with two ends of the chilling roller; the cooling component comprises a hollow cooling roller and a cooling water circulation system communicated with the two ends of the cooling roller, the cooling roller is coaxially arranged on the side of the periphery of the chilling roller to form a cooling module, and the die head is arranged above the chilling roller and the cooling roller; the adjusting component is used for adjusting the distance between the chilling roller and the cooling roller in the cooling module and adjusting the relative position of the cooling module and the die head in the transverse direction. The chilling water circulation system and the cooling water circulation system are adjusted, so that the cooling effects of the two surfaces of the cast sheet are consistent, the crystallinity of the two surfaces of the film cast sheet is close to each other as much as possible, and the problem of edge warping of the film generated by the existing film cast sheet process can be well solved.

Description

Film casting sheet forming cooling device and technological method

Technical Field

The invention relates to the field of production of polymer films, in particular to a film casting sheet forming cooling device and a process method.

Background

At present, the film extrusion casting sheet process mainly comprises two processes: firstly, water cooling; the second is air cooling. The air cooling mode is that an extruded sheet is cast on a chill roll, one surface of the extruded sheet is naturally cooled by contacting with air, and the other surface of the extruded sheet is attached to the chill roll and is cooled by contacting with the chill roll for heat exchange. The water cooling mode is that the film sheet is tightly attached to the surface of a chilling roller by a film fixing air knife, and then the sheet enters a water bath for cooling. Both of these two casting methods have a technical drawback: when the sheet is cast from a die onto a chill roll, the sheet is instantly converted from a viscous state to an elastomer, and in the process, because the cooling media on the two surfaces of the sheet are different, the heat conductivity coefficients of the media are greatly different, (in a water cooling mode and a gas cooling mode, the heat conduction media on the two surfaces of the sheet are respectively air and metal, and the heat conductivity coefficients of the air and the metal are more than 100 times different), the cooling rate difference of the two surfaces of the sheet is large, and finally, the crystallization degrees of the two surfaces of the film sheet are greatly different, and the edge warping phenomenon is easily caused on the final product. The utility model provides a film casting process improves on the basis of current casting process, can cast the piece shaping at the film simultaneously, avoids appearing two surfaces of film because of the inconsistent stick up limit problem that appears of degree of crystallinity.

Disclosure of Invention

The present invention is directed to a cooling apparatus and a cooling method for thin film casting, which solves one or more of the problems of the prior art and provides at least one of the advantages of the present invention.

The technical scheme adopted for solving the technical problems is as follows:

the invention provides a film casting sheet forming cooling device, which comprises: the chilling component comprises a hollow chilling roller and a chilling water circulating system communicated with two ends of the chilling roller; the cooling component comprises a hollow cooling roller and a cooling water circulation system communicated with the two ends of the cooling roller, the cooling roller is coaxially arranged on the side of the periphery of the chilling roller to form a cooling module, and the die head is arranged above the chilling roller and the cooling roller; the adjusting assembly is used for adjusting the distance between the chill roller and the cooling roller in the cooling module and adjusting the relative position of the cooling module and the die head in the transverse direction.

This film casting piece shaping cooling device's beneficial effect is: when the film casting device is used, a film coming out of the die head enters a space between the chilling roller and the cooling roller for solid cooling, the sheet is in contact with the chilling roller and the cooling roller in a viscous state, a traditional film fixing air knife is omitted, the cooling roller is used instead to play a role in fixing the film, the cooling effect of the film sheet is improved, the chilling roller is independently provided with a chilling water circulation system, the cooling roller is independently provided with a cooling water circulation system, the chilling water circulation system and the cooling water circulation system can be adjusted, so that the cooling effects of two sides of a cast sheet are consistent, the crystallinities of the two sides of the film cast sheet are close to each other as much as possible, and the problem of edge warping of the film generated in the existing film cast sheet process can be well solved; in addition, the relative position of the cooling module and the die head can be adjusted through the adjusting component, namely the relative position of the cast sheet and the cooling module can be adjusted to change the contact angle and the contact area, the cooling effect of the film is controlled, and the relative position between the cooling roller and the chill roller in the cooling module can be adjusted to adapt to the production of the cast sheets with different materials and different thicknesses.

As a further improvement of the technical scheme, the number of the cooling rollers is multiple, and the multiple cooling rollers are annularly arranged on the periphery of the chilling roller at intervals.

According to the scheme, the film casting sheet is cooled and fixed through the plurality of cooling rollers, and a channel for the film casting sheet to pass through the cooling and fixing is formed between the plurality of cooling rollers and the chill roller, so that the film casting sheet is cooled more uniformly, and the problem of edge warping of a film generated under the existing film casting sheet process is further solved.

As a further improvement of the technical scheme, each cooling roller is provided with an independent cooling water circulation system. According to actual requirements, the cooling effect of each cooling water circulation system is controlled, and the cooling temperature of the cooling roller is adjusted to meet different cast sheet production requirements.

As a further improvement of the technical scheme, the cooling roller and the chilling roller respectively comprise a hollow roller body and circulating heat conduction pipes penetrating through two ends of the roller body, the circulating heat conduction pipes and the inner peripheral wall of the roller body form a heat conduction cavity, two ends of the heat conduction cavity are arranged in a sealing mode, and heat conduction liquid is filled in the heat conduction cavity.

When the circulating heat conduction pipe is passed through by the cooling liquid in the water circulating system, heat exchange is carried out between the pipe wall of the circulating heat conduction pipe and the heat conduction liquid in the heat conduction cavity, and the heat conduction liquid exchanges heat with the wall body of the roller body, so that the cooling temperature of the peripheral wall of the roller body is uniformly distributed, and the phenomenon that local cooling is nonuniform in the cast piece is avoided.

As a further improvement of the above technical solution, the circulation heat conduction pipe is in a spiral pipe shape or a straight pipe shape.

The spiral tubular circulation heat conduction pipe can enable the coolant to stay in the circulation heat conduction pipe for a longer time, so that the heat exchange time between the coolant and the heat conduction liquid in the heat conduction cavity is longer, the heat exchange effect is better, the flow resistance of the straight-through tubular circulation heat conduction pipe to the coolant is smaller, and the flow resistance of a water circulation system is reduced.

As a further improvement of the technical scheme, the chilling water circulating system and the cooling water circulating system respectively comprise a water storage tank, a circulating pump, a refrigerating machine and a heating machine which are connected with each other.

The scheme pushes the cooling water to flow between the roller body and the water storage tank through the circulating pump, and the arranged refrigerating machine and the heating machine can respectively cool and heat the cooling water, so that the water temperature can be flexibly controlled.

As a further improvement of the above technical solution, the cooling device further comprises a cooling water tank filled with deionized water, and a part of the plurality of cooling rollers is immersed in the cooling water tank.

When the film casting piece is used, deionized water is filled into the cooling water tank, and the film casting piece is formed after being soaked in the deionized water, so that the cleaning effect is achieved.

As a further improvement of the technical scheme, the cooling device further comprises a rack, the adjusting assembly comprises a sliding frame which is slidably mounted on the rack, a general adjusting member for driving the sliding frame to transversely move, a cooling adjusting member and a chilling adjusting member which are mounted on the sliding frame, the chilling roller and the cooling roller are slidably mounted on the sliding frame, the cooling adjusting member is in transmission connection with the cooling roller, and the chilling adjusting member is in transmission connection with the chilling roller.

The sliding frame is driven by the general adjusting component to transversely move relative to the rack, the relative position of the cooling module and the die head arranged on the sliding frame is adjusted, and the relative position of the casting sheet and the cooling module is adjusted under the condition that the position of the die head is not changed so as to change the contact angle; and the cooling adjusting member is used for independently driving the cooling roller to transversely move, and the chilling adjusting member is used for independently driving the chilling roller to transversely move so as to be suitable for the production of casting sheets made of different materials and different thicknesses.

As a further improvement of the technical scheme, the chill roll and the cooling roll are both metal components. The metal component has better heat conduction effect, the cooling media on the two surfaces are both metal in the process of converting the contact film sheet into the elastomer, the cooling rate is similar, the crystallinity of the finished product is also similar, and the problem of edge warping of the film generated by the existing film casting process can be better solved.

In addition, the invention also provides a film cast sheet forming and cooling process method, which adopts the film cast sheet forming and cooling device and comprises the following specific steps:

firstly, adjusting the relative positions of a chilling roller, a cooling roller and a die head through an adjusting assembly according to the material and the thickness of a prefabricated film casting sheet;

then, operating a chilling water circulating system and a cooling water circulating system;

after the film is cast through a die opening of the die head, the flow rate and the temperature of circulating water are adjusted, and the fluid is cooled and formed between a chilling roller and a cooling roller.

The crystallinity of both surfaces of the film sheet can be indirectly controlled by controlling the flow rate and temperature of the circulating water in the chill roll and chill roll, and the rate of heat transfer between both surfaces of the film sheet when they contact both rolls.

Drawings

The invention is further explained by the following figures and embodiments;

FIG. 1 is a schematic view of a film casting cooling apparatus according to an embodiment of the present invention;

FIG. 2 is a schematic view of an embodiment of the water circulation system provided by the present invention;

FIG. 3 is a cross-sectional view of one embodiment of a straight through tubular circulating heat pipe in a chill roll or chill roll provided by the present invention;

FIG. 4 is a cross-sectional view of an embodiment of the present invention in which the circulating heat pipe is formed in a spiral pipe shape.

Detailed Description

Reference will now be made in detail to the present embodiments of the present invention, preferred embodiments of which are illustrated in the accompanying drawings, wherein the drawings are provided for the purpose of visually supplementing the description in the specification and so forth, and which are not intended to limit the scope of the invention.

In the description of the present invention, it should be understood that the orientation or positional relationship referred to in the description of the orientation, such as the upper, lower, front, rear, left, right, etc., is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the description of the present invention, if words such as "a plurality" are described, the meaning is one or more, the meaning of a plurality is two or more, more than, less than, more than, etc. are understood as excluding the present number, and more than, less than, etc. are understood as including the present number.

In the description of the present invention, unless otherwise explicitly limited, terms such as arrangement, installation, connection and the like should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific contents of the technical solutions.

Referring to fig. 1 to 4, the cooling apparatus for forming a thin film cast sheet according to the present invention is made in the following embodiments:

the film cast sheet forming and cooling device of the embodiment comprises a frame 700, a die head 100, a chilling component, a cooling component and a regulating component.

The die head 100 is fixedly arranged on the frame 700, the die head 100 faces downwards, and the chilling assembly comprises a chilling roller 200 and a chilling water circulation system, wherein the axis of the chilling roller 200 extends forwards and backwards, the chilling roller 200 is of a hollow structure, and the chilling water circulation system is communicated with two ends of the chilling roller 200.

The chilling water circulation system of the embodiment comprises a water storage tank 500, a circulating pump 510, a refrigerator 520 and a heater 530 which are connected between the water storage tank 500 and the circulating pump 510, wherein the water storage tank 500, the refrigerator 520, the heater 530, the circulating pump 510 and the chilling roller 200 are sequentially connected in a closed loop mode through pipelines, and the water storage tank 500 and the pipelines are wrapped by heat-preservation cotton for heat insulation.

And the cooling assembly comprises a cooling roller 300 and a cooling water circulation system, wherein the axis of the cooling roller 300 extends forwards and backwards, the cooling roller 300 is of a hollow structure, and the cooling water circulation system is communicated with two ends of the cooling roller 300.

The cooling water circulation system of the present embodiment also includes a water storage tank 500, a circulation pump 510, a refrigerator 520 and a heater 530 connected between the water storage tank 500 and the circulation pump 510, the water storage tank 500, the refrigerator 520, the heater 530, the circulation pump 510 and the cooling roller 300 are sequentially connected in a closed loop through pipes, the cooling roller 300 is disposed at the side of the outer periphery of the chill roller 200 to form a cooling module, and the die head 100 at this time is located above the space between the chill roller 200 and the cooling roller 300.

The cooling roll 300 of the present embodiment has a smaller diameter than the chill roll 200, and for the production of biaxially oriented polypropylene films and cast polypropylene films, specifically: the diameter of the chill roll 200 is 2500 mm-3500 mm, the wall thickness is more than or equal to 100mm, the surface is chromed and mirror polished to 50 +/-25 nm according to the GB/T2523-2008 measuring method, the diameter of the chill roll 300 is preferably 600 mm-700 mm, the wall thickness is 20 mm-35 mm, the surface is chromed and mirror polished to 50 +/-25 nm according to the GB/T2523-2008 measuring method.

The chill roll 200 and the cooling roll 300 of this embodiment have the same structure, and each include a roll body 400 and a circulation heat pipe 410, the roll body 400 is a hollow structure, the circulation heat pipe 410 penetrates through two ends of the roll body 400, a heat conduction cavity 420 is formed between the outer peripheral wall of the circulation heat pipe 410 and the inner peripheral wall of the roll body 400, two ends of the heat conduction cavity 420 are sealed, the circulation heat pipe 410 is an SU304 stainless steel tube, the roll body 400 is a metal member, and the heat conduction performance of the roll body 400 and the circulation heat pipe 410 is good.

The circulation heat pipe 410 may have a spiral pipe structure, and the spiral pipe circulation heat pipe 410 may make the coolant stay in the circulation heat pipe 410 for a longer time, so that the heat exchange time between the coolant and the heat conducting liquid in the heat conducting chamber 420 is longer, and the heat exchange effect is better.

In other embodiments, the circulation heat pipe 410 may have a straight pipe shape, and the straight pipe shape of the circulation heat pipe 410 has smaller flow resistance to the cooling liquid, thereby reducing the flow resistance of the water circulation system.

The water circulation system is connected to two ends of the circulation heat pipe 410.

The heat conducting cavity 420 is filled with heat conducting liquid, which is low viscosity (less than or equal to 250 centipoises) heat conducting oil in the embodiment.

When the circulation heat pipe 410 that coolant liquid among the water circulating system passes through, the pipe wall through circulation heat pipe 410 carries out the heat transfer with the heat conduction liquid in the heat conduction chamber 420, and the heat transfer is carried out with the wall body of roll body 400 to the heat conduction liquid, makes the cooling temperature evenly distributed of roll body 400 periphery wall like this, avoids the casting piece to appear the inhomogeneous phenomenon of local cooling.

The circulation pump 510 is used to drive the cooling water to flow between the circulation heat pipe 410 and the water storage tank 500, and the refrigerator 520 and the heater 530 are provided to cool and heat the cooling water respectively, so as to flexibly control the temperature of the cooling water.

The water temperature in the chill roll 300 is typically controlled to range from 2 c to 60 c, while the pure water medium temperature of the chill roll 200 is typically set between 25 c and 65 c.

Further, the number of the cooling rollers 300 is two, the two cooling rollers 300 are sequentially arranged at intervals on the periphery of the chill roller 200, and each cooling roller 300 is provided with a separate cooling water circulation system, so that the cooling effect of each cooling water circulation system is controlled according to actual requirements, and the cooling temperature of the cooling roller 300 is adjusted to meet different cast piece production.

While neither the chill roll 200 nor the cooling roll 300 are metal components. The metal component has better heat conduction effect, the cooling media on the two surfaces are both metal in the process of converting the contact film sheet into the elastomer, the cooling rate is similar, the crystallinity of the finished product is also similar, and the problem of edge warping of the film generated by the existing film casting process can be better solved.

In other embodiments, the number of cooling rollers 300 may be greater, with a plurality of such cooling rollers 300 being annularly spaced about the periphery of the chill roller 200. The film casting sheet is cooled and fixed through the cooling rollers 300, and a channel for the film casting sheet to pass through the cooling and fixing type is formed between the cooling rollers 300 and the chilling roller 200, so that the film casting sheet is cooled more uniformly, and the problem of edge warping of the film generated in the existing film casting sheet process is further solved.

And, this embodiment also has the cooling water tank 600, when using, the inside of the cooling water tank 600 is filled with deionized water, the cooling roller 300 of the downstream of this embodiment is soaked in the deionized water of the cooling water tank 600, and the lower portion of the chill roller 200 is also soaked in the deionized water, when using, the cooling water tank 600 is filled with deionized water, the film casting sheet will be formed after being soaked by the ionized water, playing a role of cleaning.

The low-temperature water in the cooling roller 300 exchanges heat by the cooling roller 300, which is soaked downstream in the cooling water tank 600, to maintain the temperature of the water in the cooling water tank 600 constant.

When the die head is used, a film from the die head 100 enters between the chill roll 200 and the cooling roll 300 for solid cooling, the sheet is in contact with the chill roll 200 and the cooling roll 300 in a viscous state, a traditional film fixing air knife is omitted, the cooling roll 300 is used instead to play a role in film fixing, the cooling effect of the film sheet is improved, the chill roll 200 is independently provided with a chill water circulation system, and the cooling roll 300 is independently provided with a cooling water circulation system, the cooling effects of the two sides of a cast sheet are consistent through adjustment of the chill water circulation system and the cooling water circulation system, the crystallinity of the two sides of the film cast sheet is enabled to be as close as possible, and the problem of edge warping of the film generated under the existing film cast sheet process can be well solved.

The adjusting assembly of this embodiment functions to adjust the distance between the chill roll 200 and the chill roll 300 in the cooling module, and to adjust the relative position of the cooling module and the die head 100, the direction of adjustment being primarily in the transverse direction.

That is, the relative position between the cast piece and the cooling module can be adjusted to change the contact angle and the contact area, control the cooling effect of the film, and adjust the relative position between the cooling roller 300 and the chill roller 200 in the cooling module, so as to adapt to the production of cast pieces with different materials and different thicknesses.

Specifically, the method comprises the following steps: the adjusting assembly comprises a sliding frame 800, a total adjusting member 710, a cooling adjusting member 810 and a chilling adjusting member 820, wherein the sliding frame 800 is transversely and transversely arranged on the rack 700 in a left-right sliding mode, the total adjusting member 710 is fixed on the rack 700, the total adjusting member 710 is in transmission connection with the sliding frame 800, the chilling roller 200 and the cooling roller 300 are both arranged on the sliding frame 800 in a left-right sliding mode, the cooling adjusting member 810 is in transmission connection with the cooling roller 300, and the chilling adjusting member 820 is in transmission connection with the chilling roller 200.

In the embodiment, the general adjustment member 710 drives the sliding frame 800 to move transversely relative to the rack 700, adjusts the relative positions of the cooling module mounted on the sliding frame 800 and the die head 100, and adjusts the relative positions of the cast slab and the cooling module to change the contact angle under the condition that the position of the die head 100 is not changed; and the cooling roller 300 is driven to transversely move by the cooling adjusting member 810, and the chilling roller 200 is driven to transversely move by the chilling adjusting member 820, so that the method is suitable for the production of casting sheets made of different materials and with different thicknesses.

The total adjusting member 710, the cooling adjusting member 810 and the chilling adjusting member 820 of the embodiment all adopt a driving structure of a hydraulic screw and have a self-locking function.

The embodiment also provides a film casting sheet forming and cooling process method, which specifically comprises the following steps:

firstly, according to the material and thickness of a thin film cast sheet to be prefabricated, the sliding frame 800 is driven to move to a set position through the total adjusting component 710 and is locked, namely, the cooling module is adjusted to a specified position, then the relative positions of the chilling roller 200 and the cooling roller 300 are adjusted through the chilling adjusting component 820 and the cooling adjusting component 810, the contact angle and the contact area of the sheet with the chilling roller 200 and the cooling roller 300 are adjusted, and the cooling effect of the thin film is controlled;

then, the circulation pump 510 is started, and the cooling water temperature and flow rate in each water circulation system are adjusted by the refrigerator 520 and the heater 530, so as to control the cooling temperature of the outer peripheral walls of the chill roller 200 and the cooling roller 300;

after that, the film flows from the die of the die head 100, and then flows between the chill roller 200 and the cooling roller 300, and the fluid flows between the chill roller 200 and the cooling roller 300 to realize cooling solidification.

While the preferred embodiments of the present invention have been illustrated and described, it will be understood by those skilled in the art that the present invention is not limited to the details of the embodiments shown and described, but is capable of numerous equivalents and substitutions without departing from the spirit of the invention as set forth in the claims appended hereto.

Claims (10)

1. The utility model provides a film casting piece shaping cooling device which characterized in that: it includes:

a die head (100);

the chilling component comprises a hollow chilling roller (200) and a chilling water circulation system communicated with two ends of the chilling roller (200);

the cooling assembly comprises a hollow cooling roller (300) and a cooling water circulation system communicated with two ends of the cooling roller (300), the cooling roller (300) is coaxially arranged on the side of the periphery of the chilling roller (200) to form a cooling module, and the die head (100) is arranged above the chilling roller (200) and the cooling roller (300);

an adjustment assembly for adjusting the spacing between the chill roll (200) and the cooling roll (300) in the die set, and adjusting the relative position of the cooling die set and the die head (100) in the transverse direction.

2. The apparatus for cooling a thin film cast sheet as claimed in claim 1, wherein:

the number of the cooling rollers (300) is multiple, and the multiple cooling rollers (300) are arranged on the periphery of the chilling roller (200) at intervals in an annular mode.

3. A film casting sheet forming cooling apparatus as claimed in claim 2, wherein:

each cooling roller (300) is provided with an independent cooling water circulation system.

4. The apparatus for cooling a thin film cast sheet as defined in claim 1, wherein:

the cooling roller (300) and the chilling roller (200) both comprise a hollow roller body (400) and circulating heat-conducting pipes (410) penetrating through two ends of the roller body (400), the circulating heat-conducting pipes (410) and the inner peripheral wall of the roller body (400) form a heat-conducting cavity (420), two ends of the heat-conducting cavity (420) are sealed, and heat-conducting liquid is filled in the heat-conducting cavity (420).

5. The apparatus for cooling a thin film cast sheet as claimed in claim 4, wherein:

the circulating heat conducting pipe (410) is in a spiral pipe shape or a straight pipe shape.

6. The apparatus for cooling a thin film cast sheet as claimed in claim 1, wherein:

the chilled water circulating system and the cooling water circulating system respectively comprise a water storage tank (500), a circulating pump (510), a refrigerating machine (520) and a heating machine (530) which are connected with each other.

7. The apparatus for cooling a thin film cast sheet as claimed in claim 2, wherein:

the cooling device further comprises a cooling water tank (600) filled with deionized water, and a part of the plurality of cooling rollers (300) is soaked in the cooling water tank (600).

8. The apparatus for cooling a thin film cast sheet as defined in claim 1, wherein:

the cooling device is characterized by further comprising a rack (700), the adjusting assembly comprises a sliding frame (800) slidably mounted on the rack (700), a general adjusting member (710) driving the sliding frame (800) to move transversely, a cooling adjusting member (810) and a chilling adjusting member (820) mounted on the sliding frame (800), the chilling roller (200) and the cooling roller (300) are slidably mounted on the sliding frame (800), the cooling adjusting member (810) is in transmission connection with the cooling roller (300), and the chilling adjusting member (820) is in transmission connection with the chilling roller (200).

9. The apparatus for cooling a thin film cast sheet as claimed in claim 1, wherein: the chill roll (200) and the chill roll (300) are both metal components.

10. A film casting sheet forming and cooling process method is characterized in that: the film casting sheet forming cooling device as claimed in any one of claims 1 to 9 is adopted, and the specific method is as follows:

firstly, adjusting the relative positions of a chill roll (200), a cooling roll (300) and a die head (100) through an adjusting assembly according to the material and the thickness of a prefabricated thin film cast sheet;

then, operating a chilling water circulating system and a cooling water circulating system;

after the film is cast through a die of the die head (100), the flow rate and the temperature of circulating water are adjusted, and the fluid is cooled and formed between a chill roll (200) and a cooling roll (300).

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