WO2022032405A1

WO2022032405A1 - Thin film follow-on foaming device and thin film follow-on foaming method

Info

Publication number: WO2022032405A1
Application number: PCT/CN2020/000305
Authority: WO
Inventors: 陈昭楷; 孙兆麟; 郑武胜
Original assignee: 广东金明精机股份有限公司
Priority date: 2020-08-14
Filing date: 2020-12-16
Publication date: 2022-02-17
Also published as: CN112123746B; CN112123746A

Abstract

A thin film follow-on foaming device, comprising first drawing pinch rollers (1) and second drawing pinch rollers (2). A heating cabinet (4) is provided between the first drawing pinch rollers (1) and the second drawing pinch rollers (2). The second drawing pinch rollers (2) comprise a second fixed roller (21) and a second movable roller (22), and also provided is a second horizontal cylinder (3) for driving the second movable roller (22) to move horizontally. Below the second fixed roller (21), an auxiliary press roller (5) is provided, and also provided is a press roller drive cylinder (53) for driving the auxiliary press roller (5) to move. The auxiliary press roller (5) comprises a roller core (51), and multiple circular rollers (52) sleeved on the periphery of the roller core (51). All circular rollers (52) have the same diameter. The diameter of the circular rollers (52) is greater than the diameter of the roller core (51). The circular rollers (52) are arranged along the axial direction of the roller core (51), but a gap is maintained between every two adjacent circular rollers (52) along the axial direction of the roller core (51).

Description

Film subsequent foaming equipment and film subsequent foaming method

technical field

The invention belongs to the technical field of film production, and particularly relates to a subsequent film foaming device and a film subsequent foaming method.

Background technique

Plastic films can be produced by the blown film method. During the production process of the film, the plastic melt is extruded upward from the annular extrusion opening of the die 91 to form a film bubble 81. As shown in FIG. 1, a vertical air inlet duct 92 is arranged in the center of the die. Air can be blown into the film bubble 81 from the vertical air inlet pipe 92 in the center of the die head, thereby inflating the film bubble 81, and then the film bubble runs through the traction nip roller 93 located above the die head to be flattened to form a film. 80, after which the film 80 is wound up. In the above production process, only one film bubble is formed, so it is also called the single film bubble process. Most ordinary films generally use the single film bubble process.

However, another part of the film (such as heat shrinkable film) cannot be fully formed in place by one blow, or if the heat shrinkable film has only one blow molding, its performance will be poor, so these films generally require multiple blows. Forming, and each inflation molding needs to form a corresponding film bubble, that is, it needs to use a multi-double film bubble process, such as a double film bubble process or even a triple film bubble process.

In the multi-bubble process, the process of forming a bubble for the first time (referred to as the first bubble) is exactly the same as that of the single-bubble process. After the film bubble 81 (referred to as the first bubble for short) is formed for the first time, the film bubble is flattened to form a thin film (referred to in the line as a bubble). 2, in order to continue to inflate and stretch, the second bubbling is called the second bubbling, and sometimes even the third bubbling is required, correspondingly, the third bubbling is called the third bubbling. Except for the first bubble, every subsequent bubble is called subsequent bubble.

The subsequent foaming process is different from the foaming process of the first foam. This is because, as shown in FIG. 2 , the first bubble 81 is extruded from the annular extrusion port of the die head 1, that is, one end of the film bubble 81 (the first bubble) is rooted in the die head 1, and the die head 1 can be used The vertical air inlet pipe 92 in the center of the head blows compressed air into the membrane bubble 81 . When the film 80 is subsequently foamed, the upper and lower ends of the film bubble 82 (the second bubble) are clamped by the traction nip rollers (the traction nip roller 1 and the traction nip roller 2), and there is no participation of the die 1. There is no vertical air inlet duct 92 that can blow compressed air directly into the bubble.

The structure of the existing equipment for subsequent foaming of the film is shown in Figure 2, including a first traction nip roll 1 and a second traction nip roll 2, the first traction nip roll 1 is located above the second traction nip roll 2, and the first traction nip roll 2 is located above the second traction nip roll 2. A heating box 4 is provided between the nip roll 1 and the second traction nip roll 2, and the heating box 4 is provided with a heating element 41; the first traction nip roll 1 includes a first fixed roll 11 and a first movable roll 12, the first fixed roll The roller 11 and the first movable roller 12 are parallel to each other and their vertical positions are flush, the position 11 of the first fixed roller 11 is fixed, the first fixed roller 11 has a first motor that drives its rotation, and is also provided with The first horizontal cylinder that drives the first movable roller 12 to move horizontally, the first horizontal cylinder drives the first movable roller 12 to leave or be close to the first fixed roller 11; the second traction nip roller 2 includes a second fixed roller 21 and a second movable roller The roller 22, the second fixed roller 21 and the second movable roller 22 are parallel to each other and their vertical positions are flush. The second motor is also provided with a second horizontal cylinder 3 that drives the second movable roller 22 to move horizontally. The second horizontal cylinder 3 drives the second movable roller 22 to leave or approach the second fixed roller 21 .

The process of subsequent foaming of the existing film is as follows:

The first movable roller 12 and the first fixed roller 11 are opened, and the film 80 is conveyed from the upstream station on the production line to the first pulling nip roller. The film 80 has been foamed by other stations upstream of the production line and then quenched. And is folded into a double-layered film, as shown in Figure 3 (the double-layered film is in a ring shape before being folded into a double-layered film), the worker pulls the film 80 through between the first fixed roll 11 and the first movable roll 12, and then the first The horizontal cylinder drives the first movable roller 12 to move horizontally in the direction of the first fixed roller 11, the first movable roller 12 is clamped with the first fixed roller 11, and the first traction nip roller 1 starts to pinch the film to move downward; the worker continues The end of the pulling film 80 moves downward, the film passes through the heating box 4, and then passes downward between the second fixed roll 22 and the second movable roll 21 of the second pulling nip roll 2, and then the worker pulls the end of the film 80 down. Tighten, and use the air gun to pass through the bundle opening at the end of the film to inflate the middle of the film, so that the film is expanded to become the second bubble 82. During this process, the heating box is heated and the film bubble is heated up. When the film bubble temperature reaches At the critical value of melting, the second bubble 82 starts to expand and the diameter gradually increases. When the diameter of the second bubble 82 reaches the set value, the second horizontal cylinder 3 drives the second movable roller 22 to the second fixed roller. The direction of 21 moves horizontally, the second movable roller 22 is sandwiched with the second fixed roller 21, the inner cavity of the film bubble is completely sealed, the air in the inner cavity of the film bubble remains in the inner cavity of the film bubble, and the subsequent foaming process is completed.

However, the above foaming process has the following problems:

1. During the heating and inflation of the film bubble, due to the need to continuously inflate the inner cavity of the film bubble, the second traction pinch roller must be kept open, so the lower end of the film bubble cannot be clamped and fixed, and the film bubble is in the vertical position. The failure to straighten up means that the shape of the membrane bubble is unstable, and the membrane bubble is easy to sway from side to side and move from side to side under the impact of the compressed air flow, which makes the diameter and volume control of the membrane bubble inaccurate; The indeterminate film bubble is easy to be too close to or even touch the heating element of the heating box, which can easily lead to partial rupture of the film bubble. Once the film bubble is partially ruptured, it means that the foaming fails and must be restarted;

2. During the foaming process, the upstream film is still continuously produced, extruded and transported. Therefore, if the foaming process takes too long, the continuous upstream film will be accumulated in the subsequent foaming equipment. If it cannot be opened and digested in time, it may cause film entanglement and cause foaming failure. Therefore, the shorter the time required for the subsequent foaming process, the better. However, in the existing subsequent foaming equipment mentioned above, since the film must pass through between the second movable roller and the second fixed roller as soon as possible, and in order to allow the film bubbles that are broken and broken during the production process to be able to escape from the second movable roller as soon as possible Passing through and escaping between the roller and the second fixed roller (to avoid accidents such as fire caused by the film staying in the heating box for a long time), the opening of the second movable roller and the second fixed roller is required to be large enough, which means that the film During the whole process of inflation, the opening width at the lower end of the bubble is very large, which requires a larger stroke of the cylinder driving the second movable roller; while the opening width at the lower end of the film bubble is large, although it is beneficial to allow the gas to quickly enter the film bubble in the initial stage of inflation However, with the increase of the air pressure in the inner cavity of the membrane bubble, the large opening width of the lower end of the membrane bubble is not conducive to maintaining the air in the inner cavity of the membrane bubble, which makes the whole inflation process time-consuming and is not conducive to shortening the length of the foaming time;

3. In the above process, when the inflation is completed and it is detected that the film bubble increases to the set diameter, the second traction nip roller begins to close; but as mentioned above, the distance between the second movable roller and the second fixed roller is very large when they are opened. , the cylinder stroke of the second movable roller is large, the film bubble is greatly deformed during the closing and clamping process of the second traction pinch roller, and the second movable roller needs to move a large range and a long moving time during the closing process, that is, the detection The distance between the time point when the diameter of the bubble meets the set value and the time point after the actual closing is relatively long, so that the shape of the bubble after closing is relative to the shape of the bubble before closing (that is, it is detected that the diameter of the bubble reaches the set value. The bubble shape) changes greatly, so there may be a big difference between the shape of the bubble when the diameter meets the set value and the shape of the bubble after the final closure, which means that the accuracy of the bubble diameter control during the foaming process needs to be Increase (during the foaming process, the diameter of the bubble determines the volume of air inside the bubble, which in turn determines the size of the bubble).

Due to the above-mentioned reasons, the diameter control accuracy of the subsequent foaming of the film in the prior art is low, and the foaming failure rate is high, and it is often necessary to repeatedly foam the film to successfully form the film bubble.

Utility model content

The purpose of the present invention is to overcome the above shortcomings and provide a film subsequent foaming equipment and a film subsequent foaming method, which can improve the success rate of foaming and improve the accuracy of the diameter of the film bubbles obtained by foaming.

Its purpose can be achieved according to the following scheme: a film subsequent foaming device, comprising a first pulling nip roll and a second pulling nip roll, the first pulling pinch roll is located above the second pulling pinch roll, the first pulling pinch roll and the second pulling pinch roll A heating box is arranged between the traction rollers, and the heating box is provided with a heating element;

The first traction nip roller includes a first fixed roller and a first movable roller. The first fixed roller and the first movable roller are parallel to each other and their vertical positions are flush. The position of the first fixed roller is fixed and the first The fixed roller is provided with a first motor that drives its rotation, and is also provided with a first horizontal cylinder that drives the first movable roller to move horizontally, and the first horizontal cylinder drives the first movable roller to leave or be close to the first fixed roller;

The second traction nip roller includes a second fixed roller and a second movable roller, the second fixed roller and the second movable roller are parallel to each other and their vertical positions are flush, the position of the second fixed roller is fixed, the second The fixed roller is provided with a second motor that drives its rotation, and is also provided with a second horizontal cylinder that drives the second movable roller to move horizontally, and the second horizontal cylinder drives the second movable roller to leave or be close to the second fixed roller;

It is characterized in that: the second horizontal cylinder is a double-stroke cylinder, and the double-stroke cylinder has two strokes and can push the second movable roller away by two different distances; when the double-stroke cylinder is in a fully retracted state, the second The movable roller is far away from the second fixed roller; when the double-stroke cylinder realizes the first stroke, the second movable roller is close to the second fixed roller, but there is a gap between them; when the double-stroke cylinder realizes the second stroke , the second movable roller is close to the second fixed roller;

There is also an auxiliary pressing roller under the second fixed roller, and a pressing roller driving cylinder for driving the auxiliary pressing roller to move, and the pressing roller driving cylinder drives the auxiliary pressing roller to leave or approach the second fixed roller;

The auxiliary pressure roller includes a roller core and a multi-section circular roller body sleeved on the periphery of the roller core. The diameters of each circular roller body are equal, and the diameter of the circular roller body is larger than the diameter of the roller core. The axial arrangement of the roll core is distributed, but there is a gap along the axial direction of the roll core between every two adjacent circular roll bodies;

Between the lower end of the heating box and the second traction nip roll, there is also an ultrasonic diameter measuring instrument for measuring the diameter of the film bubble; a central controller is also provided, the ultrasonic diameter measuring instrument is connected to the central controller, and the central controller is connected to the double-stroke cylinder and pressure roller drive cylinder.

The double-stroke cylinder includes two cylinder units, each cylinder unit includes a cylinder block and a piston rod, the piston rods of the two cylinder units protrude in opposite directions relative to the corresponding cylinder block, and the piston rods of the two cylinder units are located on the same straight line. , the cylinder bodies of the two cylinder units are connected together, the position of the piston rod of the first cylinder unit is fixed, and the piston rod of the second cylinder unit is connected to the second movable roller; when the piston rod of the first cylinder unit is When the cylinder block of the first cylinder unit is fully retracted and the piston rod of the second cylinder unit is fully retracted relative to the cylinder block of the second cylinder unit, the double-stroke cylinder is in a fully retracted state; when the first cylinder unit is fully retracted When the piston rod of the unit is fully protruded relative to the cylinder body of the first cylinder unit, and the piston rod of the second cylinder unit is fully retracted relative to the cylinder body of the second cylinder unit, the double-stroke cylinder realizes the first type. Stroke; When the piston rods of the two cylinder units are fully protruded relative to the corresponding cylinder block, the double-stroke cylinder realizes the second stroke.

A method for subsequent foaming of a film, using the above-mentioned device for subsequent foaming of a film, comprising the following steps:

(1) To prepare for foaming, the first fixed roller and the second fixed roller keep rotating, the first movable roller and the first fixed roller are opened, the double-stroke cylinder is in a fully retracted state, and the auxiliary pressing roller leaves the second fixed roller; the film The film is conveyed from the upstream station on the production line to the first traction nip roll. The film has been foamed and then folded into a double-layer film by the upstream station on the production line; the film first runs to the first traction nip roll. The end of the film is called the upstream end of the film;

(2) The worker pulls the upstream end of the film downward and passes between the first fixed roller and the first movable roller, and then the first horizontal cylinder drives the first movable roller to move horizontally in the direction of the first fixed roller, and the first movable roller Clamped with the first fixed roller, the first traction nip roller begins to pinch the film to move downward, and the width of the film when it passes through the first traction nip roller is b;

(3) The worker continues to pull the upstream end of the film to move down, the film passes through the heating box, then passes by the ultrasonic diameter measuring instrument, and then passes down through the second fixed roller and the second movable roller of the second traction nip roller. between the second fixed roller and the auxiliary pressing roller;

(4) After the film passes between the second fixed roller and the auxiliary pressing roller, the worker tightens the upstream end of the film, and uses an air gun to pass through the bundle opening at the upstream end of the film to inflate the middle of the film, so that the first traction clamp is located in the middle of the film. The film between the roller and the second traction nip roller is swelled to become a film bubble; the diameter of the film bubble gradually increases, and the upper end of the film bubble is clamped by the first traction nip roller, so that the position of the upper end of the film bubble is fixed;

(5) The worker moves with the air gun and continues to pull the upstream end of the film to the downstream; when the diameter of the film bubble measured by the ultrasonic diameter measuring instrument reaches 2b/π×a ₁ , the central controller commands the double-stroke cylinder to act to achieve In the first stroke, the second movable roller is close to the second fixed roller, but there is still a gap between the two, where a ₁ is the first conversion coefficient of the bulging degree of the film bubble, and the value of a ₁ ranges from 0.6 to 0.75 ;

(6) The worker continues to hold the air gun to move and pull the upstream end of the film to the downstream of the production line. During this process, the air gun continues to inflate the middle of the film, and the inflated air also diffuses into the film bubble, so that the diameter of the film bubble continues to increase. When the bubble diameter measured by the ultrasonic diameter measuring instrument reaches 2b/π×a ₂ , the pressure roller driving cylinder drives the auxiliary pressure roller to approach the second fixed roller, so that the circular roller body of the auxiliary pressure roller is abutted against the second fixed roller; where a ₂ is the second conversion coefficient of the bubbling degree of the film bubble, and the value of a ₂ ranges from 0.80 to 0.90; after the circular roller body of the auxiliary pressing roller is abutted against the second fixed roller, the lower end of the film bubble is moved by the second fixed roller. It is clamped with the circular roller body of the auxiliary pressure roller, and the second fixed roller and the auxiliary pressure roller also begin to pinch the film to move downward, thereby straightening the film bubble and making the position of the central axis of the film bubble stable; the air gun blows out the film. The air pressure generated by the air is transmitted to the inner cavity of the film bubble through the gap between the roller core of the auxiliary pressing roller and the second fixed roller;

(7) Workers continue to hold the air gun to move and pull the upstream end of the film to the downstream of the production line. The heating box heats the film bubble to heat up the film bubble. When the temperature of the film bubble reaches the critical value of melting, the film bubble begins to inflate ; After the film bubble is inflated, the volume of the inner cavity of the film bubble increases, and the air blown by the air gun continues to inflate the inner cavity of the film bubble through the gap between the roller core of the auxiliary pressing roller and the second fixed roller, so that the film bubble will not be blown due to blowing. After the expansion, the volume increases, resulting in a corresponding drop in air pressure;

(8) When the diameter of the film bubble measured by the ultrasonic diameter measuring instrument is equal to the set inflation diameter of the film bubble, the central controller commands the double-stroke cylinder to act to realize the second stroke, so that the second movable roller is close to the first Two fixed rollers, the inner cavity of the film bubble is completely sealed, and the air in the inner cavity of the film bubble remains in the inner cavity of the film bubble, and then the central controller commands the pressure roller to drive the cylinder to drive the auxiliary pressure roller to leave the second fixed roller; the air gun stops blowing air, The subsequent foaming process is completed.

The present invention has the following advantages and effects:

1. In the present invention, before the film bubble is heated, the upper and lower ends of the film bubble have been clamped and fixed, and the second fixed roller and the auxiliary pressing roller can be used to clamp the film bubble and then pinch downward, so that the The film bubble is stretched (straightened) vertically, so that the position of the center axis of the film bubble is stable, and the film bubble will not move left and right under the impact of compressed air, so that the diameter and volume of the film bubble can be accurately controlled; more importantly, Avoid the swaying film bubble too close to or even touch the heating element of the heating box, avoid local rupture of the film bubble, and improve the success rate of foaming;

2. In the process of inflating the membrane bubble, the present invention gradually reduces the width of the opening at the lower end of the membrane bubble according to the process of inflating, and even reduces to only a partial gap before the opening at the lower end of the membrane bubble is closed. , In the early stage of inflation, due to the low air pressure inside the membrane bubble, the larger opening is conducive to speeding up the inflation speed. In the later stage of inflation, due to the increase in the internal pressure of the membrane bubble, the gradual reduction of the opening is beneficial to reduce the air inside the membrane bubble. , so the length of inflation time can be shortened as a whole, which is beneficial to speed up the inflation process and shorten the length of foaming time;

3. When the inflation of the film bubble is completed and it is detected that the film bubble conforms to the set diameter, the second traction nip roller begins to close; since the lower end of the film bubble has been clamped by the second fixed roller and the auxiliary pressure roller before closing, the second The shape of the film bubble before and after the pulling nip rollers is basically unchanged. In addition, the second movable roller before the closing has been close to the second fixed roller, so the second movable roller has a small movement range and a short moving time during the closing process, that is, the detection The distance between the time point when the bubble diameter meets the set value and the time point after the final actual closing is short; the above two reasons make the bubble diameter obtained by subsequent foaming more accurate.

4. In the present invention, when the film is passed between the second movable roller and the second fixed roller, the double-stroke cylinder is completely retracted, and the width of the opening between the second movable roller and the second fixed roller can be large enough; on the other hand, If the film bubble is ruptured during the production process, the double-stroke cylinder can also be completely retracted, so that the ruptured (broken) film bubble can pass through and escape from the second movable roller and the second fixed roller as soon as possible, so as to avoid the film for a long time. Accidents such as fire caused by staying in the heating box.

Description of drawings

Figure 1 is a schematic diagram of the production equipment and production process of the single-bubble method.

Figure 2 is a schematic diagram of the production equipment and production process of the traditional double bubble method.

FIG. 3 is a schematic diagram of the cross-sectional structure of the film after it is folded into a double layer.

FIG. 4 is a schematic structural diagram of a specific embodiment of the present invention.

FIG. 5 is a schematic structural diagram of the double-stroke cylinder and the second movable roller in FIG. 1 .

FIG. 6 is a schematic diagram of the structure of the auxiliary pressing roller and the second fixed roller.

FIG. 7 is a schematic diagram of an intermediate state of step (2) of the second embodiment of the present invention.

FIG. 8 is a schematic diagram of the result state of step (2) of the second embodiment of the present invention.

FIG. 9 is a schematic diagram of the result state of step (3) of the second embodiment of the present invention.

FIG. 10 is a schematic diagram of the result state of step (4) of the second embodiment of the present invention.

FIG. 11 is a partial enlarged schematic view of FIG. 10 .

FIG. 12 is a schematic diagram of the result state of step (5) of the second embodiment of the present invention.

FIG. 13 is a partial enlarged schematic view of FIG. 12 .

FIG. 14 is a schematic diagram of step (6) of the second embodiment of the present invention.

FIG. 15 is a partial enlarged schematic view of FIG. 14 .

FIG. 16 is a schematic diagram of an intermediate state of step (8) of the second embodiment of the present invention.

FIG. 17 is a partial enlarged schematic view of FIG. 16 .

detailed description

Example 1

A film subsequent foaming device shown in FIG. 4 includes a first pulling nip roll 1 and a second pulling nip roll 2, the first pulling nip roll 1 is located above the second pulling nip roll 2, the first pulling nip roll 1 and A heating box 4 is provided between the second traction nip rolls 2, and the heating box is provided with heating elements; the first traction nip roll 1 includes a first fixed roll 11 and a first movable roll 12. The first fixed roll 11 and the first movable roll The rollers 12 are parallel to each other and their vertical positions are flush (that is, in the same vertical position). The position of the first fixed roller 11 is fixed. There is a first horizontal cylinder 13 that drives the first movable roller 12 to move horizontally, and the first horizontal cylinder 13 drives the first movable roller 12 to leave or approach the first fixed roller 11; the second traction nip roller 2 includes a second fixed roller 21 and a The second movable roller 22, the second fixed roller 21 and the second movable roller 22 are parallel to each other and their vertical positions are flush, the position of the second fixed roller 21 is fixed, and the second fixed roller 21 is driven to rotate The second motor is also provided with a second horizontal cylinder 3 that drives the second movable roller 22 to move horizontally, and the second horizontal cylinder 3 drives the second movable roller 22 to leave or be close to the second fixed roller; the second horizontal cylinder 3 is The double-stroke cylinder, as shown in FIG. 5 and FIG. 13 , has two strokes and can push the second movable roller 22 away by two different distances. The double-stroke cylinder includes two cylinder units, each cylinder unit Including a cylinder block and a piston rod, the cylinder block 32 of the first cylinder unit is connected with the cylinder block of the second cylinder unit 34, and the position of the piston rod 31 of the first cylinder unit is fixed (with the frame 90 of the equipment). fixed connection), the piston rod 33 of the second cylinder unit is connected to the second movable roller 22; the piston rod 31 of the first cylinder unit and the piston rod 33 of the second cylinder unit are located on the same line, and the two cylinder units The protruding direction of the piston rod relative to the corresponding cylinder block is opposite. In FIG. 5, the protruding direction of the piston rod 31 of the first cylinder unit relative to the cylinder block 32 of the first cylinder unit is to the left of the drawing. The protruding direction of the piston rod 33 of the second cylinder unit relative to the cylinder block 34 of the second cylinder unit is to the right of the drawing; when the piston rod 31 of the first cylinder unit is relative to the When the cylinder block 32 of one cylinder unit is fully retracted and the piston rod 33 of the second cylinder unit is also fully retracted relative to the cylinder block 34 of the second cylinder unit, the double-stroke cylinder 3 is in a fully retracted state; when the first cylinder unit is in a fully retracted state; When the piston rod 31 of the first cylinder unit is fully protruded relative to the cylinder body 32 of the first cylinder unit, and the piston rod 33 of the second cylinder unit is fully retracted relative to the cylinder body of the second cylinder unit 34, the double The stroke cylinder 3 realizes the first stroke; when the piston rods of the two cylinder units are fully protruded relative to the corresponding cylinder block (that is, the piston rod 31 of the first cylinder unit is relative to the cylinder of the first cylinder unit) The body 32 is fully protruded, and at the same time the piston rod 33 of the second cylinder unit is also fully protruded relative to the cylinder block 34 of the second cylinder unit), the double-stroke cylinder 3 is realized The second itinerary.

When the double-stroke cylinder 3 is in a fully retracted state, the second movable roller 22 is away from the second fixed roller 21, as shown in Figures 9, 10, and 11; when the double-stroke cylinder 3 realizes the first stroke, the first The two movable rollers 22 are close to the second fixed roller 21, but there is a gap between them, as shown in Fig. 12 and Fig. 13 ; when the double-stroke cylinder 3 realizes the second stroke, the second movable roller 22 is in close contact with each other. the second fixed roller 21, as shown in Figure 16 and Figure 17;

As shown in FIGS. 4 , 6 , 15 and 16 , an auxiliary pressure roller 5 is further provided below the second fixed roller 21 , and a pressure roller driving cylinder 53 for driving the auxiliary pressure roller 5 to move is also provided. 53 Drive the auxiliary pressure roller 5 away from or close to the second fixed roller; as shown in FIG. 6 , the auxiliary pressure roller 5 includes a roller core 51, a multi-section circular roller body 52 sleeved on the periphery of the roller core, and each segment of the circular roller body 52 The diameters of the circular roller bodies 52 are equal to the diameter of the roller core 51, and the circular roller bodies 52 of each section are arranged and distributed along the axial direction of the roller core 51. There is a gap in the axial direction of the roll core 51 .

As shown in Figure 4, between the lower end of the heating box 4 and the second traction nip roller 2, an ultrasonic diameter measuring instrument 6 for measuring the diameter of the film bubble is also provided; a central controller is also provided, and the ultrasonic diameter measuring instrument is connected to the central controller, The central controller is connected to the double stroke cylinder 3 and the roller drive cylinder 53 .

Embodiment 2

(1) To prepare for foaming, the first fixed roller 11 and the second fixed roller 21 keep rotating, and the first movable roller 12 and the first fixed roller 11 of the first traction nip roller 1 are opened (that is, the first movable roller 12 leaves The first fixed roller 11, the two are not clamped together), the double-stroke cylinder 3 is in a fully retracted state, and the auxiliary pressing roller 5 leaves the second fixed roller 21; The film 80 is conveyed by the roller 1, and the film 80 has been foamed and then folded into a double-layer film by other stations upstream of the production line, as shown in Figure 3 (the double-layer film is annular before being folded into a double-layer film); The film 80 first runs to one end of the first pulling nip roll (end A in Fig. 7, Fig. 8, Fig. 9, Fig. 10), which is called the upstream end of the film;

(2) The worker pulls the upstream end of the film 80 downward through the first fixed roller 11 and the first movable roller 12, as shown in FIG. 7, and then the first horizontal cylinder 13 drives the first movable roller 12 to the first movable roller 12. The direction of the fixed roller 11 moves horizontally, and the first movable roller 12 is clamped with the first fixed roller 11. As shown in FIG. 8, the first traction nip roller 1 starts to move the film 80 downward, and the film 80 passes through the first traction The width value of the nip roll 1 is b (because the film 80 is a double layer, when the film is expanded into a circular shape in the subsequent steps, its total circumference is 2b, as shown in Figure 3);

(3), the worker continues to pull the upstream end of the film 80 to move downward, the film 80 runs through the heating box 4, then passes by the ultrasonic diameter measuring instrument 6, and then passes downward through the second fixed position of the second pulling nip roller 2 Between the roller 21 and the second movable roller 22, and then pass between the second fixed roller 21 and the auxiliary pressing roller 5, as shown in FIG. 9;

(4) After the film 80 passes between the second fixed roller 21 and the auxiliary pressing roller 5, the worker tightens the upstream end of the film 80, and uses the air gun 7 to pass through the bundle opening at the upstream end of the film to inflate the middle of the film 80, The film located between the first traction nip roll 1 and the second traction nip roll 2 is bulged to become a film bubble 82, the diameter of the film bubble 82 is gradually increased, and the upper end of the film bubble 82 is clamped by the first traction nip roll 1 , so that the position of the upper end of the membrane bubble 82 is fixed, as shown in Figure 10 and Figure 11;

(5), the worker moves with the air gun 7 and continues to drag the upstream end of the film 80 to the downstream; when the diameter of the film bubble 82 measured by the ultrasonic diameter measuring instrument 6 reaches 2b/π×a ₁ (where a ₁ is the film bubble drum The first conversion coefficient of the opening degree, a ₁ is 0.7 in this embodiment, and b is the width value of the film 80 when it passes through the first traction nip roller 1), the central controller commands the piston rod of the first cylinder unit 31 is completely extended relative to the cylinder block 32 of the first cylinder unit, while the piston rod 33 of the second cylinder unit remains fully retracted relative to the cylinder block 34 of the second cylinder unit, and the double-stroke cylinder 3 realizes the first type stroke, so that the second movable roller 22 is close to the second fixed roller 21, but there is still a gap between the two, as shown in Figure 12 and Figure 13;

(6), the worker continues to hold the air gun 7 to move and pull the upstream end of the film 80 to the downstream of the production line. During this process, the air gun 7 continues to inflate the middle of the film, and the inflated air also diffuses into the film bubble 82, so that the film bubble 82 The diameter continues to increase, when the diameter of the film bubble measured by the ultrasonic diameter measuring instrument 6 reaches 2b/π×a ₂ (where a ₂ is the second conversion coefficient of the bulging degree of the film bubble, and the value range of a ₂ in this embodiment is 0.85), the pressure roller driving cylinder 53 drives the auxiliary pressure roller 5 to approach the second fixed roller 21, so that the circular roller body 52 of the auxiliary pressure roller abuts against the second fixed roller 21, as shown in Figures 14 and 15; After the circular roller body 52 of the pressing roller abuts against the second fixed roller 21, the lower end of the film bubble 82 is clamped by the second fixed roller 21 and the circular roller body 52 of the auxiliary pressing roller, and the second fixed roller 21 and the auxiliary pressing roller The circular roller body 52 of the pressure roller also begins to assist the pinch film to move downward, thereby straightening the film bubble 82 and stabilizing the position of the central axis of the film bubble 82; the air pressure generated by the air blown by the air gun 7 passes through the auxiliary pressure roller The gap between the roller core 51 and the second fixed roller is transmitted to the inner cavity of the film bubble 82;

(7), the worker continues to hold the air gun 7 to move and pull the upstream end of the film to the downstream of the production line. The heating box 4 heats the film bubble to heat the film bubble 82. When the temperature of the film bubble 82 reaches the critical value of melting, the film bubble 82 starts to inflate; after the film bubble 82 is inflated, the volume of the inner cavity of the film bubble 82 increases, and the air blown by the air gun continues to flow into the film bubble 82 through the gap between the roller core 51 of the auxiliary pressing roller and the second fixed roller 21 The cavity is inflated, so that the air pressure of the membrane bubble 82 will not decrease accordingly due to the increase in volume after inflation;

(8) When the bubble diameter measured by the ultrasonic diameter measuring instrument is equal to the set bubble diameter, the central controller commands the piston rod 31 of the first cylinder unit to be relative to the cylinder body of the first cylinder unit 32 is fully protruded, and at the same time, the piston rod 33 of the second cylinder unit is also fully protruded relative to the cylinder body 34 of the second cylinder unit. The double-stroke cylinder 3 realizes the second stroke, so that the second movable roller 22 is in close contact with each other. With the second fixed roller 21, the inner cavity of the film bubble 82 is completely sealed, and the air in the inner cavity of the film bubble remains in the inner cavity of the film bubble, as shown in Figures 16 and 17; then the central controller commands the pressure roller to drive the cylinder 53 to drive The auxiliary pressing roller 5 leaves the second fixed roller 21; the air gun 7 stops blowing air, and the subsequent foaming process is completed.

In the above-mentioned second embodiment, the value of the first conversion coefficient a ₁ of the bulging degree of the film bubble can be changed to 0.60 or 0.75;

In the above-mentioned second embodiment, the value of the second conversion coefficient a ₂ of the bubbling degree of the film bubble can be changed to 0.80 or 0.90.

Claims

A film subsequent foaming device includes a first pulling nip roll and a second pulling pinch roll, the first pulling pinch roll is located above the second pulling pinch roll, and a heating device is arranged between the first pulling pinch roll and the second pulling pinch roll The heating box is provided with heating elements; the first traction nip roller includes a first fixed roller and a first movable roller, the first fixed roller and the first movable roller are parallel to each other and their vertical positions are flush, and the first fixed roller and the first movable roller are parallel to each other. The position of the roller is fixed, the first fixed roller has a first motor that drives its rotation, and a first horizontal cylinder that drives the first movable roller to move horizontally. The first horizontal cylinder drives the first movable roller away from or close to the first roller. a fixed roller;

The second traction nip roller includes a second fixed roller and a second movable roller, the second fixed roller and the second movable roller are parallel to each other and their vertical positions are flush, the position of the second fixed roller is fixed, the second The fixed roller is provided with a second motor that drives its rotation, and is also provided with a second horizontal cylinder that drives the second movable roller to move horizontally, and the second horizontal cylinder drives the second movable roller to leave or be close to the second fixed roller;

It is characterized in that: the second horizontal cylinder is a double-stroke cylinder, and the double-stroke cylinder has two strokes and can push the second movable roller away by two different distances; when the double-stroke cylinder is in a fully retracted state, the second The movable roller is far away from the second fixed roller; when the double-stroke cylinder realizes the first stroke, the second movable roller is close to the second fixed roller, but there is a gap between them; when the double-stroke cylinder realizes the second stroke , the second movable roller is close to the second fixed roller;

There is also an auxiliary pressing roller under the second fixed roller, and a pressing roller driving cylinder for driving the auxiliary pressing roller to move, and the pressing roller driving cylinder drives the auxiliary pressing roller to leave or approach the second fixed roller;

The auxiliary pressure roller includes a roller core and a multi-section circular roller body sleeved on the periphery of the roller core. The diameters of each circular roller body are equal, and the diameter of the circular roller body is larger than the diameter of the roller core. The axial arrangement of the roll core is distributed, but there is a gap along the axial direction of the roll core between every two adjacent circular roll bodies;

Between the lower end of the heating box and the second traction nip roll, there is also an ultrasonic diameter measuring instrument for measuring the diameter of the film bubble; a central controller is also provided, the ultrasonic diameter measuring instrument is connected to the central controller, and the central controller is connected to the double-stroke cylinder and pressure roller drive cylinder.
The film subsequent foaming device according to claim 1, wherein the double-stroke cylinder includes two cylinder units, each cylinder unit includes a cylinder block and a piston rod, and the piston rods of the two cylinder units are opposite to the corresponding cylinders The direction of the body protruding is opposite, the piston rods of the two cylinder units are located on the same line, the cylinder blocks of the two cylinder units are connected together, the piston rod of the first cylinder unit is in a fixed position, and the piston rod of the second cylinder unit is connected. The second movable roller; when the piston rod of the first cylinder unit is completely retracted relative to the cylinder body of the first cylinder unit, and the piston rod of the second cylinder unit is relative to the cylinder body of the second cylinder unit When fully retracted, the double-stroke cylinder is in a fully retracted state; when the piston rod of the first cylinder unit is fully extended relative to the cylinder block of the first cylinder unit, and the piston rod of the second cylinder unit is fully retracted relative to the second cylinder unit. When the cylinder blocks of each cylinder unit are completely retracted, the double-stroke cylinder realizes the first stroke; when the piston rods of the two cylinder units are fully protruded relative to the corresponding cylinder block, the double-stroke cylinder realizes the second stroke.
A film subsequent foaming method, using the film subsequent foaming device according to claim 1 or 2, comprising the following steps:

(1) To prepare for foaming, the first fixed roller and the second fixed roller keep rotating, the first movable roller and the first fixed roller are opened, the double-stroke cylinder is in a fully retracted state, and the auxiliary pressing roller leaves the second fixed roller; the film The film is conveyed from the upstream station on the production line to the first traction nip roll. The film has been foamed and then folded into a double-layer film by the upstream station on the production line; the film first runs to the first traction nip roll. The end of the film is called the upstream end of the film;

(2) The worker pulls the upstream end of the film downward and passes between the first fixed roller and the first movable roller, and then the first horizontal cylinder drives the first movable roller to move horizontally in the direction of the first fixed roller, and the first movable roller Clamped with the first fixed roller, the first traction nip roller begins to pinch the film to move downward, and the width of the film when it passes through the first traction nip roller is b;

(3) The worker continues to pull the upstream end of the film to move down, the film passes through the heating box, then passes by the ultrasonic diameter measuring instrument, and then passes down through the second fixed roller and the second movable roller of the second traction nip roller. between the second fixed roller and the auxiliary pressing roller;

(4) After the film passes between the second fixed roller and the auxiliary pressing roller, the worker tightens the upstream end of the film, and uses an air gun to pass through the bundle opening at the upstream end of the film to inflate the middle of the film, so that the first traction clamp is located in the middle of the film. The film between the roller and the second traction nip roller is swelled to become a film bubble; the diameter of the film bubble gradually increases, and the upper end of the film bubble is clamped by the first traction nip roller, so that the position of the upper end of the film bubble is fixed;

(5) The worker moves with the air gun and continues to pull the upstream end of the film to the downstream; when the diameter of the film bubble measured by the ultrasonic diameter measuring instrument reaches 2b/π×a 1 , the central controller commands the double-stroke cylinder to act to achieve In the first stroke, the second movable roller is close to the second fixed roller, but there is still a gap between the two, where a 1 is the first conversion coefficient of the bubbling degree of the film bubble, and the value of a 1 ranges from 0.6 to 0.75 ;

(6) The worker continues to hold the air gun to move and pull the upstream end of the film to the downstream of the production line. During this process, the air gun continues to inflate the middle of the film, and the inflated air also diffuses into the film bubble, so that the diameter of the film bubble continues to increase. When the bubble diameter measured by the ultrasonic diameter measuring instrument reaches 2b/π×a 2 , the pressure roller driving cylinder drives the auxiliary pressure roller to approach the second fixed roller, so that the circular roller body of the auxiliary pressure roller is abutted against the second fixed roller; where a 2 is the second conversion coefficient of the bubbling degree of the film bubble, and the value of a 2 ranges from 0.80 to 0.90; after the circular roller body of the auxiliary pressing roller is abutted against the second fixed roller, the lower end of the film bubble is moved by the second fixed roller. It is clamped with the circular roller body of the auxiliary pressure roller, and the second fixed roller and the auxiliary pressure roller also begin to move the film downward, thereby straightening the film bubble and making the central axis position of the film bubble stable; the air gun blows out The air pressure generated by the air is transmitted to the inner cavity of the film bubble through the gap between the roller core of the auxiliary pressing roller and the second fixed roller;

(7) Workers continue to hold the air gun to move and pull the upstream end of the film to the downstream of the production line. The heating box heats the film bubble to heat up the film bubble. When the temperature of the film bubble reaches the critical value of melting, the film bubble begins to inflate ; After the film bubble is inflated, the volume of the inner cavity of the film bubble increases, and the air blown by the air gun continues to inflate the inner cavity of the film bubble through the gap between the roller core of the auxiliary pressing roller and the second fixed roller, so that the film bubble will not be blown due to blowing. After the expansion, the volume increases, resulting in a corresponding drop in air pressure;

(8) When the diameter of the film bubble measured by the ultrasonic diameter measuring instrument is equal to the set inflation diameter of the film bubble, the central controller commands the double-stroke cylinder to act to realize the second stroke, so that the second movable roller is close to the first Two fixed rollers, the inner cavity of the film bubble is completely sealed, and the air in the inner cavity of the film bubble remains in the inner cavity of the film bubble; then the central controller instructs the pressure roller to drive the cylinder to drive the auxiliary pressure roller to leave the second fixed roller; the air gun stops blowing air, The subsequent foaming process is completed.