JP6987984B2 - PET foam sheet cooling device - Google Patents

Description

The present invention relates to a cooling device for a PET (Polyethylene terephthalate) foamed sheet.

Conventional foam sheets are widely used in applications where light weight and cushioning properties are required.

Generally, the foamed sheet is continuously manufactured by an extrusion method or the like, and when the foamed sheet is manufactured by such a manufacturing method, the temperature control on the extruder die (Die) side is the quality of the foamed sheet. Will affect.

In the conventional PET foaming process, the extruder die is cooled due to the cooling air of the cooling device injected to the extruder die side, and the temperature of the die becomes non-uniform, which makes it difficult to manufacture a foamed sheet. was there.

In particular, there is a problem that the foamed sheet may be torn due to the influence of excessive cooling air.

Therefore, the current situation is that the development of an apparatus for improving the quality of the foamed sheet and producing a uniform sheet is required.

The present invention relates to a PET foam sheet cooling device for solving the above-mentioned problems, and is uniform by blocking the direct injection of the cooling air of the cooling device to the extruder die side. An attempt is made to provide a cooling device for a PET foam sheet capable of producing a foam sheet.

Further, in order to stably control the surface of the PET sheet after foaming, the foamed sheet can be stretched more efficiently by using a heater, and at the same time, the physical properties of the foamed sheet are improved and the thickness of the foamed sheet is increased. It is an object of the present invention to provide an apparatus and a method for producing a PET foam sheet capable of producing a pet with a thickness of 10 mm or less, particularly 1 mm or less.

In order to achieve the above object, the cooling air is directed toward the die side of the extruder from which the foamed sheet is discharged, and the discharge portion for injecting the cooling air in the first direction; A flow guide that is located and blocks the flow of cooling air discharged from the discharge unit in the first direction and guides the cooling air to the second direction; in the opposite direction from the discharge unit to the first direction. It is located at a predetermined interval along a certain second direction, has an inflow hole into which the air discharged from the flow guide unit flows, and is an exhaust for exhausting the air flowing in through the inflow hole to the second direction side. parts and body provided with; see contains, said flow guide unit, based on the imaginary reference line orthogonal to the center axis of the body, provided such cooling air is discharged in the second direction, The flow guide portion is arranged in the direction of the central axis of the main body, and has an inlet and an inlet for cooling air that has passed through the discharge portion in the central region; Provided is a cooling device having a plurality of discharge ports, which are located at predetermined intervals along a circumferential direction with respect to the central axis of the main body and discharge cooling air that has passed through an inlet.

In addition to this, an extruder having a die in which the foam sheet raw material flows in and the foam sheet is discharged; a cooling device for cooling the foam sheet discharged from the extruder; and the foam that has passed through the cooling device. The cooling device includes a cutter for cutting the sheet; and a discharge unit for injecting cooling air in the first direction toward the die; and is located at a predetermined distance in the first direction from the discharge unit. , A flow guide unit that blocks the flow of the cooling air discharged from the discharge unit in the first direction and guides the cooling air to the second direction side; a second direction opposite to the first direction from the discharge unit. Located at predetermined intervals along the two directions, it has an inflow hole into which the air discharged from the flow guide section flows in, and an exhaust section for exhausting the air flowing in through the inflow hole to the second direction side. a body provided; only contains the flow guide unit, based on the imaginary reference line orthogonal to the center axis of the body, provided such cooling air is discharged in the second direction, wherein the flow The guides are located in the central axis direction of the main body, at the inlet where the cooling air that has passed through the discharge part flows into the central region; at the ends located at predetermined intervals in the direction orthogonal to the central axis of the main body. Provided is an apparatus for producing a foam sheet, which is located at a predetermined interval along a circumferential direction with respect to the central axis of the main body and has a plurality of discharge ports for discharging cooling air that has passed through an inlet.

According to the cooling device of the present invention, by blocking the direct radiation of the cooling air of the cooling device to the die side of the extruder, a uniform foamed sheet can be produced and the cooling air of the cooling device can be manufactured. It is possible to smoothly induce the flowability and improve the processability of producing the foamed sheet.

Further, according to the foamed sheet manufacturing apparatus of the present invention, in order to control the melt viscosity (strength) of the PET foamed sheet, the mixing ratio of the raw materials is improved through the optimum mixing ratio of the raw materials and the precise temperature control of the extruder. And by controlling the crystallinity, a uniform foamed sheet can be produced.

Further, according to the manufacturing apparatus and manufacturing method of the present invention, the thickness of the foamed sheet can be easily adjusted while stretching the PET foamed sheet, and the thickness can be manufactured to 1 mm or less, and after the stretching process is performed. , The physical characteristics of the foamed sheet can be improved, the durability can be improved, and the smoothness of the surface portion by the heater can be induced.

It is a side view which shows the cooling apparatus by one Embodiment of this invention. It is a side view which shows the cooling apparatus by one Embodiment of this invention. (A) is a side view of a flow guide unit according to an embodiment of the present invention. It is a front view of the flow guide part by one Embodiment of this invention. It is a figure for demonstrating the flow path of the cooling air of the cooling apparatus by one Embodiment of this invention. It is a schematic diagram which shows the manufacturing apparatus of the foamed sheet by one Embodiment of this invention. It is a schematic diagram which shows the manufacturing apparatus of the foamed sheet by one Embodiment of this invention. It is a schematic diagram of the cutter by one Embodiment of this invention. It is a schematic diagram which shows the manufacturing apparatus of the foamed sheet by another embodiment of this invention. It is a flow chart of the manufacturing method of the foamed sheet by one Embodiment of this invention.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms and words used herein and in the scope of claim shall not be construed in a general or lexical sense only, and the inventor describes his invention in the best possible way. In order to do so, it must be interpreted as a meaning or concept consistent with the technical idea of the present invention, based on the principle that the concept of terms can be properly defined.

Also, regardless of the drawing code, the same or corresponding components are given the same or similar reference numbers, duplicate description of this is omitted, and the size of each component shown for convenience of description. And the shape can be exaggerated or reduced.

Therefore, the embodiments described herein and the configurations shown in the drawings are merely one of the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. It must be understood that at the time of this application, there may be a variety of equivalents and variants that can replace them.

The present invention relates to a cooling device for PET foam sheets, and the present invention relates to a cooling device capable of improving the quality of foam sheets to produce a uniform sheet.

1 and 2 are side views showing a cooling device according to an embodiment of the present invention, FIG. 3A is a side view of a flow guide unit according to an embodiment of the present invention, and FIG. 4 is a side view. , FIG. 5 is a front view of a flow guide unit according to an embodiment of the present invention, FIG. 5 is a diagram for explaining a flow path of cooling air of a cooling device according to an embodiment of the present invention, and FIG. 6 is a diagram. It is a process diagram which shows the PET foam sheet manufacturing process by one Embodiment of this invention, FIG. 7 is a schematic diagram which shows the manufacturing apparatus of a foam sheet, and FIG. 8 is a schematic diagram of a cutter by one Embodiment of this invention. Is.

First, the terms "first direction and second direction" used in the present application refer to the arrow direction indicated by d1 with respect to the central axis d shown in FIG. 1 as the first direction, and the second direction as the first direction. It means the direction of the arrow indicated by d2, which is the direction opposite to the direction.

In particular, the arrow direction indicated by d1 means a direction toward the die side, which will be described later, and the arrow direction indicated by d2 means a direction toward the exhaust portion side.

Explaining with reference to FIG. 1, the cooling device 10 of the present invention includes a discharge unit 100, a flow guide unit 200, and a main body 300.

More specifically, the discharge unit 100 can inject cooling air in the first direction d1.

Further, the flow guide unit 200 is located at a predetermined interval from the discharge unit 100 in the first direction d1, blocks the cooling air discharged from the discharge unit 100 from flowing in the first direction d1, and cools air. Can be guided to the second direction d2 side.

In addition to this, the main body 300 is located at a predetermined interval along the second direction d2 opposite to the first direction d1, and includes an inflow hole 410 into which the air discharged from the flow guide unit 200 flows.

Further, an exhaust unit 310 is provided in order to exhaust the air that has flowed in through the inflow hole 410 to the second direction d2 side.

Here, the flow guide unit 200 can further include a fixing member 210 for being arranged at a predetermined interval from the discharge unit 100.

Further, as shown in FIG. 2, the flow guide unit 200 is connected to the discharge unit 100 so as to be able to move the fluid, and the passage member 220 for fixing the fluid flow passage and the flow guide unit 200 is fixed. Instead of the member 210, it can be further included.

On the other hand, referring to FIGS. 3A and 4A, the flow guide unit 200 of the present invention is used for cooling on the second direction d2 side with reference to a virtual reference line R orthogonal to the central axis d of the main body 300. Air can be discharged.

Further, the flow guide unit 200 includes an inflow port 201 in the central region and a plurality of discharge ports 202 located at the end portions at predetermined intervals along the circumferential direction.

The cooling air that has passed through the discharge unit 100 may flow in through the inflow port 201 of the flow guide unit, and the cooling air that has passed through the inflow port 201 may be discharged through the plurality of discharge ports 202.

Here, the inflow port 201 and the plurality of discharge ports 202 each include a plurality of channels 203 that are movably connected to each other.

In particular, the channel 203 of the flow guide unit 200 is provided so as to bend and flow at least once before the cooling air that has passed through the inflow port 201 is discharged.

Further, the channel 203 is provided so as to bend at an acute angle θ from the reference line R toward the second direction d2 side.

For example, the acute angle θ can be in an angle range of 0 degrees or more and less than 90 degrees, more preferably an inclination angle in the range of 10 degrees to 80 degrees, but is not limited thereto.

As an example, as shown in FIG. 3A, the channel 203 may have an angle θ ₁ within the acute angle range from the reference line R toward the second direction d2 side of approximately 20 degrees.

Here, as shown in FIG. 3B, when the channel 203 is located at a 90-degree angle instead of an acute angle, the cooling air is directed to the first direction d1, that is, the die side. Since it is easy to move, the die can be easily cooled and is therefore provided to have an angle within the acute angle range as described above.

On the other hand, the cooling device 10 of the present invention can further include a neck portion 400 which is connected between the exhaust portion 100 and the main body exhaust portion 310 and has a diameter smaller than that of the main body 300.

More specifically, referring to FIG. 5, an inflow hole 410 is provided on the outer peripheral surface of the neck portion 400, and the neck portion 400 is provided so as to be fluid-movable with the exhaust portion 310.

Further, referring to the arrow in FIG. 5, the cooling air discharged from the flow guide unit 200 may flow into the inflow hole 410 and be exhausted to the exhaust unit.

Here, a plurality of inflow holes 410 are provided.

In addition to this, the surface of the main body 300 of the present invention can be cooled by cooling water.

More specifically, an inflow nozzle (not shown) into which the cooling water flows can be further included so that the surface is cooled while the cooling water circulates along the inner peripheral surface of the main body 300.

The present invention also provides a foam sheet manufacturing apparatus 11.

For example, the foamed sheet manufacturing device 11 includes the above-mentioned cooling device 10, and the cooling device used in the foamed sheet manufacturing device 11 described later is the specific cooling device described in the above-mentioned cooling device 10. Matters may apply equally.

As shown in FIG. 6, in the foamed sheet manufacturing apparatus 11 according to the present invention, a foamed sheet raw material, that is, a PET chip, an additive, a foaming agent, and the like are mixed and charged into the hopper 120, and the melt extruder and the die are charged. After foaming while passing through, a PET foamed sheet can be manufactured through a cooling step and a cutting step.

Referring to FIG. 7, the foamed sheet manufacturing apparatus 11 according to the present invention includes an extruder 20 having a die 21 into which the foamed sheet raw material flows in and the foamed sheet 1 is discharged.

It also includes a cooling device 10 for cooling the foam sheet 1 discharged from the extruder 20, and a cutter 60 for cutting the foam sheet 1 that has passed through the cooling device 10.

In particular, the cooling device 10 is located at a predetermined interval from the discharge unit to the discharge unit 100 for injecting cooling air in the first direction d1 facing the die 21, and is discharged from the discharge unit. It includes a flow guide unit 200 that blocks the flow of the cooled cooling air in the first direction d1 and guides the cooling air to the second direction d2 side.

In addition to this, it has an inflow hole 410, which is located at a predetermined interval along the second direction d2, which is the opposite direction of the first direction, and into which the air discharged from the flow guide unit 200 flows in, through the inflow hole. The main body 300 is provided with an exhaust unit 310 for exhausting the inflowing air to the second direction side.

Further, the cutter 60 is provided so as to be located at the upper end 60 or the lower end 60'of the foam sheet 1 discharged in a cylindrical shape so as to cut the foam sheet 1 that has passed through the cooling device 10. Not limited.

Further, a plurality of the cutters 60 may be provided as needed, and the positions thereof may be appropriately selected and provided.

On the other hand, the extruder 20 includes a hopper 22 into which the foamed sheet raw material is charged.

Here, in order to manufacture the foamed sheet 1, a PET chip (Polyethylene terephthalate Chip), an additive and a foaming agent can be mixed and charged into the hopper 22.

As an example, 100 parts by weight of PET chip, 0.1 to 5 parts by weight of foaming gas, 0.1 to 5 parts by weight of thickener, and 0.1 to 5 parts by weight of nucleating agent can be mixed and charged. However, it is not limited to this.

The raw material charged as described above passes through the extruder 20 and the die 21 and undergoes a foaming step. At this time, the temperature of the extruder 20 is 240 to 280 degrees (° C.). It is possible, but not limited to this.

On the other hand, the surface of the main body of the cooling device 10 is cooled by the cooling water, and the foamed sheet 1 can be guided and cooled along the surface of the cooling device 10.

In addition to this, referring to FIG. 8, the foam sheet 1 discharged in a cylindrical shape from the die 21 is cooled along the surface of the cooling device, but the cutter 60 provided at the rear end of the cooling device 10 is provided. Cuts and expands a part of the area of the foam sheet 1.

Further, the cooling air may flow into the space between the foam sheet 1 and the neck portion 400 by the flow guide portion 200 and be exhausted to the exhaust portion 310 through the inflow hole 410.

Here, a part of the cooling air flows into the inflow hole 410, and a part of the cooling air forms a space between the cooling device and the foamed sheet, so that the foamed sheet is cooled and the friction generated in the sheet traveling direction is generated. Can be reduced to improve workability.

On the other hand, it is impossible to manufacture a PET foam sheet made of a crystalline polymer with a manufacturing facility of PS Foam made of a general non-crystalline polymer.

In the present invention, in order to control the melt viscosity (strength) in manufacturing a PET foam sheet, the raw materials are mixed through the optimum mixing ratio of the raw materials and the precise temperature control of the extruder as in the manufacturing process described above. By improving the properties and controlling the crystallinity, a uniform foamed sheet can be produced.

On the other hand, the present invention includes a PET foam sheet manufacturing apparatus 12 according to another embodiment. The PET foam sheet manufacturing apparatus 12 can include the PET foam sheet cooling device 10 described above.

The foamed sheet manufacturing apparatus 12 can easily adjust the thickness of the foamed sheet while stretching the foamed sheet, and can manufacture the foamed sheet to a thickness of 10 mm or less, and the physical properties of the foamed sheet are improved after the stretching process. And the durability can be improved.

FIG. 9 is a block diagram of a PET foam sheet manufacturing apparatus 12 according to another embodiment of the present invention.

Hereinafter, the PET foam sheet manufacturing apparatus 12 of the present invention will be described in detail with reference to FIGS. 8 and 9.

Explaining with reference to FIG. 9, the PET foam sheet manufacturing apparatus 12 of the present invention includes a hopper 22, an extruder 20, a cooling device 10, a first roller portion 30, a second roller portion 40, and a heater portion 50.

More specifically, the hopper 22 for charging the foam sheet raw material is included.

Further, the extruder 20 including the die 21 in which the foamed sheet raw material charged into the hopper 22 is melted and the foamed sheet 1 is discharged is included.

Here, the hopper 22 may be formed on the upper part of the extruder 20.

In order to produce the foamed sheet 1, a PET chip (Polyethylene terephthalate Chip), an additive and a foaming agent can be mixed and charged into the hopper 22.

As an example, 100 parts by weight of PET chip, 0.1 to 5 parts by weight of foaming gas, 0.1 to 5 parts by weight of thickener, and 0.1 to 5 parts by weight of nucleating agent can be mixed and charged. However, it is not limited to this.

Further, the raw material charged as described above passes through the extruder 20 and the die 21 and undergoes a foaming step. At this time, the temperature of the extruder 20 is 240 to 280 degrees (° C.). ), But is not limited to this.

In addition to this, the cooling device 10 can cool the foamed sheet 1 discharged from the extruder 20.

More specifically, the surface of the cooling device 10 can be cooled by the cooling water, and the foam sheet 1 can be guided and cooled along the surface of the cooling device 10.

Here, the cooling device 10 can further include an inflow nozzle (not shown) into which the cooling water flows so that the cooling water circulates along the inner peripheral surface and the surface is cooled.

Further, the cooling device can inject cooling air toward the die 21 to cool the foamed sheet 1 discharged from the die 21.

In addition to this, the manufacturing apparatus 12 of the present invention may further include a cutter 60 for cutting the foam sheet 1 at the rear end of the cooling apparatus 10.

Referring to FIG. 8, since the foam sheet 1 discharged from the die 21 is discharged in a cylindrical shape and passes through the cooling device 10, it is partially transferred by the cutter 60 before being transferred to the first roller portion 30. After the region of No. 3 is cut and expanded, it is transferred to the first roller portion 30.

Here, the cutter 60 is provided so as to be located at the upper end portion 60 or the lower end portion 60'of the foamed sheet 1, but is not limited thereto.

Further, a plurality of the cutters 60 may be provided as needed, and the positions thereof may be appropriately selected and provided.

On the other hand, the first roller portion 30 of the present invention includes the first upper roller 31 and the first lower roller 32 in the upper and lower portions around the foam sheet 1 so as to crimp the foam sheet 1 that has passed through the cooling device 10. Can be done.

Here, the initial thickness of the foamed sheet can be adjusted by adjusting the speed of the first roller portion 30. Since the sheet can be cut due to the high speed in the cooling device 10, it is possible to prevent the sheet from being cut by adjusting the speeds of the first upper roller 31 and the first lower roller 32 as described above. You will be able to do it.

In addition to this, the second roller portion 40 can include a second upper roller 41 and a second lower roller 42 for stretching the foam sheet 1 crimped by the first roller portion 30.

Here, the manufacturing apparatus 12 of the present invention can further include a winder (not shown) provided so as to wind up the foamed sheet 1.

The foamed sheet 1 is further wound by a included winder (not shown), and as an example, the winder may be arranged at the rear end of the second roller portion 40, but is not limited thereto.

The second upper roller 41 and the second lower roller 42 may be arranged so as to be separated from the foam sheet by a predetermined time.

The distance between the second upper roller 41 and the second lower roller 42 through which the foamed sheet 1 passes may be 0.1 to 10.0 mm.

More specifically, as described above, the distance d between the second upper roller 41 and the second lower roller 42 can improve the uniformity of the thickness of the foamed sheet and improve the gloss of the surface. There is.

In addition, the first and second upper rollers 31, 41 can rotate counterclockwise about an axis, and the first and second lower rollers 32, 42 can rotate clockwise.

Further, the heater unit 50 for heating the foamed sheet 1 may be arranged between the first roller unit 30 and the second roller unit 400.

More specifically, the heater unit 50 can include an upper heater 51 and a lower heater 52 for heating the upper and lower surfaces of the foam sheet 1.

In particular, the heater unit 50 is provided so as to be movable as needed.

Here, the heater unit 50 can be operated at 50 to 300 degrees (° C.).

Further, the heater unit 50 can use a contact type or non-contact type plate heater.

As an example, the contact plate heater can be an oil circulation type or an electric heater, and the non-contact plate heater can be an oil circulation type, an electric use type, an infrared heater (IR Heater). ..

In particular, the upper heater 501 and the lower heater 52, that is, the heater unit 50 can be contact type plate heaters, and the temperatures of the respective heaters can be heated to the same temperature to heat the foam sheet 1.

On the other hand, the PET foam sheet manufacturing apparatus 12 of the present invention can control the thickness of the foam sheet 1 by adjusting the rotation speed ratios of the first and second roller portions 30 and 40.

The rotation speed ratio of the first roller portion to the second roller portion can be 1: 1 to 1:10, and more preferably 1: 3 to 1: 8.

The thickness of the foamed sheet 1 finally produced can be controlled by the rotation speed ratio, and the foamed sheet 10 having a rotation speed ratio of 10 mm or less can be produced in the range of 1: 1 to 1:10. Specifically, the foamed sheet 1 having a rotation speed ratio in the range of 1: 3 to 1: 8 can be produced, but the present invention is not limited to this, and the rotation speed ratio varies depending on the product. Can be set. Here, the thickness of the product can be reduced as the difference in the rotation speed ratio increases.

Here, if the rotation speed ratio is 1: 3 or less, the foamed sheet 1 can be produced thicker than 1 mm, and if it is 1: 8 or more, the durability of the foamed sheet may decrease, and the foamed sheet may be produced. Breakage can occur.

Further, during the initial operation of the first and second roller portions, the rotation speed ratio of the first roller portion to the second roller portion may be 1: 1.

The initial operation means a state in which the foamed sheet 1 is spread by the cutter 60, then passed through the first roller portion 30 and transferred to the second roller portions 30, 40.

Here, at the time of the initial operation, the heater unit 50 is located outside, not between the first and second roller units.

In addition to this, after the initial operation of the first and second roller portions 30 and 40, the heater portion 50 is moved between the first and second roller portions so as to heat the upper and lower surfaces of the foam sheet 1. You can drive.

That is, after the heater section 50 is not arranged between the first and second roller sections during the initial operation, and after the foam sheet 1 is completely transferred to the second roller section, the heater section 50 is first moved. And it is moved and arranged between the second roller portions.

When the temperature of the foamed sheet 1 is raised to a point where it can be stretched by a heater, for example, to a glass transition temperature (Tg) or higher, specifically 85 degrees or higher, the speed of the second roller portion 40 is adjusted. Adjust the thickness of the foam sheet 1.

Here, the second roller portion, that is, the second upper roller and the second lower roller can be rotated at the same speed.

After the temperature of the foamed sheet 1 is raised as described above, when the speed of the second roller portion 40 is increased faster than the speed of the first roller portion 30, the foamed sheet 1 becomes the first due to the rotation speed ratio of the two roller portions. 2 Stretching is performed by being attracted to the roller portion 40 side.

Therefore, the thickness of the foamed sheet 1 that has passed through the second roller portion 40 can be manufactured to be 10 mm or less and 1 mm or less.

In particular, the foamed sheet 1 in the form of a film (Film) of 1 mm or less can be manufactured.

The surface layer is further post-foamed by the temperature at which the foamed sheet 1 is raised through the stretching step, and the structure of the cells in the foamed sheet (Cell) becomes more rigid, so that the durability of the foamed sheet 1 is improved. Can be done.

As described above, in the PET foam sheet manufacturing apparatus 12 of the present invention, the raw material is charged, the foam sheet 1 is discharged from the extruder 20, foaming is performed, and the material is cooled by passing through the cooling device 10. Later, it is cut and spread by a cutter 60 provided at the rear end of the cooling device.

After that, the foam sheet 1 passes through the first roller portion 30 and is crimped, and when the transfer to the second roller portion 40 is completed, the heater portion 50 is arranged between the first roller portion 30 and the second roller portion 40. The temperature of the foamed sheet 1 is raised to a point where it can be stretched. After the temperature is raised, the speed of the second roller portion 40 is adjusted to stretch the foamed sheet, and then the foamed sheet is wound on a winder (not shown).

Through the steps as described above, it is possible to produce a foamed sheet having a thickness of 10 mm or less, particularly 1 mm or less, and having improved durability.

Hereinafter, a method for manufacturing a PET foam sheet of the present invention using the above-mentioned manufacturing devices 11 and 12 will be described in detail with reference to FIG. 10. Therefore, as the method for manufacturing the PET foam sheet described later, the contents described in the manufacturing devices 11 and 12 and the cooling device 10 can be applied in the same manner.

The method for producing a PET foam sheet of the present invention includes a raw material charging step S100, a foam sheet cooling step S200, a foam sheet crimping step S300, a foam sheet heating step S400, and a foam sheet stretching step S500.

More specifically, the raw material charging step S100 is a step of feeding the foamed sheet raw material into the hopper 22 of the extruder 20.

In the raw material charging step S100, a PET chip (Polyethylene terephthalate Chip), an additive, and a foaming agent can be mixed and charged into the hopper 22 in order to produce the foamed sheet 1.

As an example, 100 parts by weight of PET chip, 0.1 to 5 parts by weight of foaming gas, 0.1 to 5 parts by weight of thickener, and 0.1 to 5 parts by weight of nucleating agent can be mixed and charged. However, it is not limited to this.

At this time, the temperature of the extruder 20 is controlled to 240 to 280 degrees (° C.), and the raw material charged as described above passes through the extruder 20 and the die 21 and undergoes a foaming step. ..

Next, the foamed sheet cooling step S200 is a step in which the foamed sheet 1 discharged from the extruder 20 is cooled by the cooling device 10.

More specifically, in the cooling step S200, the surface of the cooling device 10 is cooled by the cooling water flowing into the cooling device 10, and the foamed sheet 1 can be cooled.

The surface of the cooling device 10 may be cooled by cooling water, and the foam sheet 1 may be guided and cooled along the surface of the cooling device 10.

Further, in the cooling step S200, the cooling device 10 can inject cooling air toward the die 21 side of the extruder to cool the foamed sheet 1 discharged from the die 21.

In addition to this, the manufacturing method of the present invention can further include a sheet cutting step of cutting the foamed sheet 1 by a cutter 60 provided at the rear end of the cooling device 10.

Referring to FIG. 9, since the foam sheet 1 discharged from the die 21 is discharged in a cylindrical shape and passes through the cooling device 10, it is partially transferred by the cutter 60 before being transferred to the first roller portion 30. After the region of No. 3 is cut and expanded, it is transferred to the first roller portion 30.

Next, in the foamed sheet crimping step S300 of the present invention, the foamed sheet 1 is pressed by the first roller portions 30 provided at the upper and lower portions around the foamed sheet 1 so as to crimp the foamed sheet 1 that has passed through the cooling device 10. It is the stage of crimping.

The first roller portion 30 can include a first upper roller 31 and a first lower roller 32 in upper and lower portions around the foam sheet 1 so as to crimp the foam sheet 1 that has passed through the cooling device 10.

When the foam sheet 1 passes between the first upper roller 31 and the first lower roller 32, the first upper roller 31 rotates counterclockwise about an axis, and the first lower roller 32 has a shaft. The foam sheet 1 may be crimped as it rotates clockwise around the.

Here, in the crimping step S300, the initial thickness of the foamed sheet can be adjusted by adjusting the speed of the first roller portion 30. Since the sheet can be cut due to the high speed in the cooling device 10, it is possible to prevent the sheet from being cut by adjusting the speeds of the first upper roller 31 and the second lower roller 32 as described above. You will be able to do it.

Next, the foam sheet heating step S400 of the present invention is a stage in which the foam sheet 1 is heated by the heater unit 50 arranged between the first roller unit 30 and the second roller unit 40.

More specifically, in the heating step S400, the foam sheet 1 can be heated by adjusting the heater unit that can be operated at 50 to 300 degrees (° C.).

Here, the heating step S400 can further include a transfer step of transferring the foamed sheet 1 to the second roller portion 40 before heating the foamed sheet 1. That is, before the foamed sheet is heated and stretched, it can be transferred to the second roller portion 40 and then the heating step S400 can be performed.

Next, the foamed sheet stretching step S500 is a step of stretching the foamed sheet 1 by the second roller portion 40 provided for stretching the foamed sheet 1 crimped by the first roller portion 30.

Here, in the stretching step S500, the foamed sheet 1 can be stretched by arranging the second upper roller and the second lower roller so as to be separated from the foamed sheet for a predetermined period of time.

On the other hand, in the stretching step S500 of the method for producing a PET foam sheet of the present invention, the thickness of the foam sheet 1 can be controlled by adjusting the rotation speed ratios of the first and second roller portions 30 and 40.

The thickness of the foamed sheet 1 can be controlled by controlling the rotation speed ratio of the first roller portion to the second roller portion to 1: 1 to 1:10, more preferably 1: 3 to 1: 8. can.

Further, in the stretching step S500, the rotation speed ratio of the first roller portion to the second roller portion can be set to 1: 1 during the initial operation of the first and second roller portions.

The initial operation means a state in which the foamed sheet 1 is spread by the cutter 60, then passed through the first roller portion 30 and transferred to the second roller portions 30, 40.

Here, at the time of the initial operation, the heater unit 50 is located outside, not between the first and second roller units.

In addition to this, in the stretching step S500, after the initial operation of the first and second roller portions 30 and 40, the heater portion 50 of the first and second roller portions is heated so as to heat the upper and lower surfaces of the foam sheet 1. It is possible to further include a heater unit moving stage to be moved between them.

That is, after the heater section 50 is not arranged between the first and second roller sections during the initial operation, when the foam sheet 1 is completely transferred to the second roller section, the heater section 50 is moved to the first and second roller sections. It is moved and arranged between the second roller portions.

When the temperature of the foamed sheet 1 is raised to a point where it can be stretched by a heater, for example, to a glass transition temperature (Tg) or higher, specifically 85 degrees or higher, the speed of the second roller portion 40 is adjusted to foam. A step of adjusting the thickness of the sheet 1 is performed.

After the temperature of the foamed sheet 1 is raised as described above, when the speed of the second roller portion 40 is increased faster than the speed of the first roller portion 30, the foamed sheet 1 becomes the first due to the rotation speed ratio of the two roller portions. 2 The stretching step is performed by being attracted to the roller portion 40 side.

In particular, the thickness of the foamed sheet 1 that has passed through the second roller portion 40 can be manufactured to 1 mm or less.

Therefore, the thickness of the foamed sheet 1 that has passed through the second roller portion 40 can be manufactured to be 10 mm or less and 1 mm or less.

In particular, the foamed sheet 1 in the form of a film of 1 mm or less can be manufactured.

The surface layer is further post-foamed by the temperature at which the foamed sheet 1 is raised through the stretching step, and the structure of the cells in the foamed sheet becomes more solid, so that the durability of the foamed sheet 1 can be improved.

In addition to this, the present invention can further include a winding step of winding the foamed sheet 1 into a winder (not shown) after the stretching step is completed. As an example, product production can be completed by winding the foam sheet 1 around a winder arranged at the rear end of the second roller 40.

As described above, the method for producing a PET foam sheet of the present invention can produce a foam sheet having a thickness of 10 mm or less, particularly 1 mm or less, and having improved durability through the steps as described above. can.

Claims (12)

With a discharge section for injecting cooling air in the first direction toward the die side of the extruder from which the foam sheet is discharged;
A flow guide unit that is located at a predetermined distance in the first direction from the discharge unit, blocks the cooling air discharged from the discharge unit from flowing in the first direction, and guides the cooling air to the second direction side. ;
It is located at a predetermined interval from the discharge section along the second direction opposite to the first direction, has an inflow hole into which the air discharged from the flow guide section flows, and allows the air flowing in through the inflow hole to flow through the inflow hole. a main body exhaust unit is provided for evacuating the second direction side; only contains,
The flow guide unit is provided so that cooling air is discharged to the second direction side with reference to a virtual reference line orthogonal to the central axis of the main body.
The flow guide section is arranged in the direction of the central axis of the main body, and has an inlet and an inlet for cooling air that has passed through the discharge section in the central region; A cooling device having a plurality of discharge ports, which are located at predetermined intervals along a circumferential direction with respect to the central axis of the main body and discharge cooling air that has passed through an inlet. The cooling device according to claim 1 , wherein the flow guide unit has a plurality of channels for connecting the inflow port and the plurality of discharge ports so that the fluid can move. The channel of the flow guide portion is provided so as to bend and flow at least once before the cooling air passing through the inflow port is discharged, and the channel has an acute angle from the reference line toward the second direction side. The cooling device according to claim 2 , which is provided so as to bend at. It further includes a neck part that connects between the exhaust part and the main body exhaust part and has a diameter smaller than that of the main body.
The inflow hole is provided on the outer peripheral surface of the neck portion.
The cooling device according to claim 1, wherein the neck portion is provided so as to be movable with an exhaust portion and the cooling air discharged from the flow guide portion flows into the inflow hole and is exhausted to the exhaust portion. The cooling device according to claim 1, wherein the surface of the main body is provided so as to be cooled by cooling water. With an extruder having a die in which the foamed sheet raw material flows in and the foamed sheet is discharged;
With a cooling device for cooling the foamed sheet discharged from the extruder;
Includes a cutter for cutting the foam sheet that has passed through the cooling device;
The cooling device has a discharge unit for injecting cooling air in the first direction toward the die;
A flow guide unit that is located at a predetermined distance in the first direction from the discharge unit, blocks the cooling air discharged from the discharge unit from flowing in the first direction, and guides the cooling air to the second direction side. ;
It is located at a predetermined interval from the discharge section along the second direction opposite to the first direction, has an inflow hole into which the air discharged from the flow guide section flows, and allows the air flowing in through the inflow hole to flow through the inflow hole. a main body exhaust unit is provided for evacuating the second direction side; only contains,
The flow guide unit is provided so that cooling air is discharged to the second direction side with reference to a virtual reference line orthogonal to the central axis of the main body.
The flow guide section is arranged in the direction of the central axis of the main body, and has an inlet and an inlet for cooling air that has passed through the discharge section in the central region; A foam sheet manufacturing apparatus having a plurality of discharge ports, which are located at predetermined intervals along a circumferential direction with respect to the central axis of the main body and discharge cooling air that has passed through an inlet. The foam sheet manufacturing apparatus according to claim 6 , wherein the flow guide unit has a plurality of channels for connecting the inflow port and the plurality of discharge ports so as to be fluid-movable. The channel of the flow guide portion is provided so as to bend and flow at least once before the cooling air passing through the inflow port is discharged, and the channel has an acute angle from the reference line toward the second direction side. The foamed sheet manufacturing apparatus according to claim 7 , which is provided so as to bend in. It further includes a neck part that connects between the exhaust part and the main body exhaust part and has a diameter smaller than that of the main body.
The inflow hole is provided on the outer peripheral surface of the neck portion.
The foam sheet manufacturing apparatus according to claim 8 , wherein the neck portion is provided so as to be movable with an exhaust portion and the cooling air discharged from the flow guide portion flows into the inflow hole and is exhausted to the exhaust portion. .. The foamed sheet manufacturing apparatus according to claim 6 , wherein the surface of the main body is cooled by cooling water, and the foamed sheet is guided and cooled along the surface of the cooling device. The production of the foamed sheet according to claim 6 , wherein the foamed sheet discharged in a cylindrical shape from the die is cooled along the surface of the cooling device, and then a part of the foamed sheet is cut and expanded by a cutter. Device. The foamed sheet manufacturing apparatus according to claim 6 , wherein the cooling air flows into the space between the foamed sheet and the neck portion by the flow guide portion and is exhausted to the exhaust portion through the inflow hole.

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