Film making process of plastic film

Abstract

The invention discloses a plastic film making process which comprises the following steps: step 1, feeding in a hopper: adding raw material particles into the hopper of a blow molding machine, and waiting for discharging; step 2, melt extrusion; step 3, blowing up; step 4, cooling and shaping: cooling and shaping the blow-molded plastic film bubbles in sequence by a cooling device in a manner of sequentially performing water distribution, water collection and air blowing on the surfaces of the plastic film bubbles; step 5, corona treatment; and step 6, thin film rolling. And in the fourth step, cooling of the plastic film bubbles is achieved through cooling water heat exchange, cooling water evaporation heat dissipation and air cooling heat dissipation, and the cooling efficiency can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of blown annular films, and in particular to a process for making a plastic film. Background Art

[0002] Plastic film is often processed by blow molding, and the main steps of blow molding include extrusion, blow molding, cooling, guiding, pulling and winding. When cooling, the film blowing die head is connected to the air cooler. However, when the air cooling method is adopted, the nozzle position of the air cooler is fixed, and the film can only be blown to a fixed range, which makes it difficult to achieve an ideal cooling effect. In order to improve the air cooling effect of the air cooler on the plastic film, a preparation process of an agricultural environmentally friendly degradable plastic film recorded in the invention patent with the announcement number CN111844708B uses five air cooling rings spaced up and down to increase the cooling area and improve the cooling shaping efficiency, and drives the air cooling ring to move up and down reciprocatingly through an adjustment device, and at the same time reciprocates within a certain range, thereby achieving the purpose of changing the air flow cooling range and improving the cooling uniformity. However, the use of the above five air cooling rings to blow air to cool the film at the same time increases the energy consumption of the air cooler, and it is also necessary to set a control and adjustment device to change the position of the air cooling ring, increase the number of parts, and make the operation complicated.

[0003] Therefore, there is an urgent need for a film forming process that can effectively improve the cooling effect on the film. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a film-making process for a film that can effectively improve the cooling effect on the film, and the technical solution adopted includes:

[0005] A process for making a plastic film, comprising:

[0006] Step 1: Hopper loading: Add the raw material particles into the hopper of the blow molding machine and wait for unloading;

[0007] Step 2, melt extrusion;

[0008] Step 3, inflation;

[0009] Step 4, cooling and shaping: The cooling equipment cools and shapes the blown plastic film bubble by distributing water, collecting water and blowing air on the surface of the plastic film bubble in sequence;

[0010] Step 5, corona treatment;

[0011] Step 6: Film winding.

[0012] A technical solution adopted by an embodiment of the present invention to solve its technical problem is: the cooling equipment in step 4 includes a frame, a cooling water tank, a water-cooling ring, an air-cooling ring and a water collecting ring, the frame is provided with a through hole of a plastic film bubble, the water-cooling ring, the water-collecting ring and the air-cooling ring are installed in the hole wall of the through hole from top to bottom in sequence, the water-cooling ring is hollow inside and connected to the inside of the cooling water tank through a water inlet, a plurality of small holes are provided on the inner wall of the water-cooling ring, the water collecting ring is installed on the inner wall of the through hole and can contact the outer wall of the plastic film bubble.

[0013] A technical solution adopted by an embodiment of the present invention to solve its technical problem is: the horizontal height of the water collecting ring gradually decreases from the inside to the outside, the frame is provided with water outlet holes connected to the inside of the through hole, and the water outlet holes are distributed near the upper part of the outer ring of the water collecting ring.

[0014] A technical solution adopted by an embodiment of the present invention to solve its technical problem is: the inner diameter of the inner wall of the water cooling ring gradually increases from top to bottom, and the lower end of the water cooling ring is distributed directly above the water collecting ring.

[0015] A technical solution adopted by an embodiment of the present invention to solve its technical problem is: the water outlet is provided with a, and the horizontal height of the water collecting ring gradually decreases from the side away from the water outlet to the side close to the water outlet.

[0016] A technical solution adopted by an embodiment of the present invention to solve its technical problem is: the cooling equipment also includes a cooling device, which is used to cool the cooling water in the cooling water tank, and the cooling water tank has a water supply port and a water return port. The water supply port is connected to the water inlet through a water pump, and the water outlet is connected to the water return port.

[0017] The beneficial effects of the present invention are as follows: the cooling of the plastic film bubble is achieved through cooling water heat exchange, cooling water evaporation heat dissipation and air cooling heat dissipation, which is beneficial to improving the cooling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0019] Figure 1 This is a schematic diagram of the structure of the cooling device in the film-making process of the plastic film of the present application;

[0020] Figure 2 It is a cross-sectional view of the cooling device in the film-making process of the plastic film of the present application. DETAILED DESCRIPTION

[0021] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0022] In the description of the present invention, the meaning of "above", "below", "exceed", etc. is not inclusive of the number itself, and the meaning of "above", "below", "within", etc. is inclusive of the number itself. If there is a description of "first" or "second", it is only used to distinguish the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0023] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0024] In the present invention, unless otherwise clearly defined, the words "set", "install", "connect" and the like should be understood in a broad sense, for example, they can be directly connected or indirectly connected through an intermediate medium; they can be fixedly connected or detachably connected or integrally formed; they can be mechanically connected; they can be the internal connection of two elements or the interaction relationship between two elements. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0025] Reference Figure 1 to Figure 2 , an embodiment of the present application is proposed, and the film-making process of the plastic film described in this embodiment is characterized by comprising:

[0026] Step 1: Hopper loading: Add plastic granules into the hopper of the blow molding machine and wait for unloading;

[0027] Step 2, melt extrusion: the plastic particles in the hopper are put into the extruder to extrude the tubular parison;

[0028] Step 3, inflation: After clamping the tubular preform in the mold cavity and sealing the bottom, compressed air is introduced into the inner cavity of the tubular preform to inflate and form a film bubble;

[0029] Step 4, cooling and shaping: The cooling equipment cools and shapes the blown plastic film bubble by distributing water, collecting water and blowing air on the surface of the plastic film bubble in sequence;

[0030] Step 5, corona treatment: the corona equipment performs corona discharge on the surface of the plastic film bubble;

[0031] Step 6: Film winding.

[0032] The cooling equipment cools and shapes the blown plastic film bubble by distributing water, collecting water and blowing air on the surface of the plastic film bubble in sequence. After distributing water on the surface of the plastic film bubble, heat exchange is generated with the plastic film bubble. The water on the surface of the plastic film bubble is collected by the water collecting ring 50 and takes away the heat on the plastic film bubble. The plastic film bubble then passes through the air cooling ring 40, and the air nozzle on the inner wall of the air cooling ring 40 blows air to the plastic film bubble. The residual water on the plastic film bubble will evaporate under the blowing action of the air cooling ring 40 and continue to take away the heat on the plastic film. At the same time, the air blown out by the air cooling ring 40 also has a cooling effect on the plastic film bubble. The cooling of the plastic film bubble is achieved through cooling water heat exchange, cooling water evaporation heat dissipation and air cooling heat dissipation, which is beneficial to improving the cooling efficiency.

[0033] Steps 1, 2, 3 and steps 5, 6 belong to the prior art in this field, and this application does not describe in detail the specific processes and equipment in steps 1, 2, 3 and steps 5, 6.

[0034] Based on the above content, in step 4, the cooling equipment includes a frame 10, a cooling water tank 20, a water-cooling ring 30, an air-cooling ring 40 and a water collecting ring 50. The frame 10 is provided with a through hole of a plastic film bubble. The water-cooling ring 30, the water collecting ring 50 and the air-cooling ring 40 are sequentially installed in the hole wall of the through hole from top to bottom. The water-cooling ring 30 is hollow inside and connected to the inside of the cooling water tank 20 through a water inlet 31. The inner wall of the water-cooling ring 30 is covered with small holes 32. The water collecting ring 50 is installed on the inner wall of the through hole and can contact the outer wall of the plastic film bubble.

[0035] The cooling water tank 20 is connected to the inside of the water cooling ring 30 through a water supply pump. The water cooling ring 30 is filled with cooling water, and the cooling water flows out through the plurality of small holes 32 and adheres to the plastic film. As shown in the drawings, the small holes 32 on the inner wall of the water cooling ring 30 are arranged in a staggered manner so that the plastic film bubble can be fully coated with cooling water for cooling, thereby avoiding uneven cooling effect.

[0036] Furthermore, the water collecting ring 50 is an annular plate body, the water collecting ring 50 is installed on the hole wall and the horizontal height of the water collecting ring 50 gradually decreases from the inside to the outside, the frame 10 is provided with a water outlet hole 51 connected to the inside of the through hole, and the water outlet hole 51 is distributed near the upper part of the outer ring of the water collecting ring 50.

[0037] Preferably, the height level of the water outlet hole 51 is explained. Furthermore, the water outlet hole 51 is provided with a water collecting ring 50, and the horizontal height of the water collecting ring 50 gradually decreases from the side away from the water outlet hole 51 to the side close to the water outlet hole 51, so that the height of the water collecting ring 50 at the water outlet hole 51 is the lowest. When water is distributed on the plastic film bubble and passes through the water collecting ring 50, the water sheet on the plastic film bubble is scraped off by the action of the water collecting ring 50, and the scraped water is collected along the surface of the water collecting ring 50 to the water outlet hole 51 and flows out from the water outlet hole 51.

[0038] Preferably, the inner diameter of the inner wall of the water-cooling ring 30 gradually increases from top to bottom, and the lower end of the water-cooling ring 30 is distributed directly above the water collecting ring 50, that is, the lower end of the water-cooling ring 30 and the projection of the water collecting ring 50 on the horizontal plane coincide with each other, and when water flows out of the surface of the water collecting ring 50 from the small hole 32, the water can flow down along the inner wall of the water-cooling ring 30 and then drip onto the surface of the water collecting ring 50 and then flow out.

[0039] Preferably, the cooling device further comprises a cooling device 60, and the cooling device 60 is used to cool the cooling water in the cooling water tank 20. The cooling water tank 20 has a water supply port and a water return port, the water supply port is connected to the water inlet 31, and the water outlet 51 is connected to the water return port. The cooling water can be cooled in the cooling water tank 20 and then transported to the cooling ring by a water pump. The cooling water collected by the water collecting ring 50 is then returned to the cooling water tank 20 through the water return port for cooling, thereby realizing the recycling of cooling water.

[0040] Of course, the present invention is not limited to the above-mentioned embodiments, and those skilled in the art may make equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications and substitutions are all included in the scope defined by the claims of this application.

Claims

1. A process for making a plastic film, characterized in that: include: Step 1: Hopper loading: Add the raw material particles into the hopper of the blow molding machine and wait for unloading; Step 2, melt extrusion; Step 3, inflation; Step 4, cooling and shaping: The cooling equipment cools and shapes the blown plastic film bubble by distributing water, collecting water and blowing air on the surface of the plastic film bubble in sequence; Step 5, corona treatment; Step 6: Film winding.

2. A process for making a plastic film according to claim 1, characterized in that: The cooling device in step 4 includes a frame (10), a cooling water tank (20), a water-cooling ring (30), an air-cooling ring (40) and a water collecting ring (50). The frame (10) is provided with a through hole of a plastic film bubble. The water-cooling ring (30), the water collecting ring (50) and the air-cooling ring (40) are sequentially installed in the hole wall of the through hole from top to bottom. The water-cooling ring (30) is hollow inside and is connected to the inside of the cooling water tank (20) through a water inlet (31). The inner wall of the water-cooling ring (30) is provided with a plurality of small holes (32). The water collecting ring (50) is installed on the inner wall of the through hole and can contact the outer wall of the plastic film bubble.

3. A process for making a plastic film according to claim 2, characterized in that: The horizontal height of the water collecting ring (50) gradually decreases from the inside to the outside, and the frame (10) is provided with water outlet holes (51) connected to the inside of the through hole, and the water outlet holes (51) are distributed at positions close to the upper part of the outer ring of the water collecting ring (50).

4. A process for making a plastic film according to claim 3, characterized in that: The inner diameter of the inner wall of the water cooling ring (30) gradually increases from top to bottom, and the lower end of the water cooling ring (30) is located directly above the water collecting ring (50).

5. A process for making a plastic film according to claim 3, characterized in that: The water outlet hole (51) is provided with a water collecting ring (50), and the level of the water collecting ring (50) gradually decreases from the side away from the water outlet hole (51) to the side close to the water outlet hole (51).

6. A process for making a plastic film according to claim 5, characterized in that: The cooling equipment also includes a cooling device (60), which is used to cool the cooling water in the cooling water tank (20). The cooling water tank (20) has a water supply port and a water return port. The water supply port is connected to the water inlet (31) through a water pump, and the water outlet (51) is connected to the water return port.

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