Melt blow molding process and device for polyetherimide film

Abstract

The present invention relates to a melt blow molding process and device for polyetherimide film. The process comprises the following steps: the raw material is melt-extruded through a screw extruder, and then metered into a blow molding device; a film bubble is blown out through a rotating die head in the blow molding device, the die head temperature is 273-278°C, the temperature inside the film bubble is controlled at 260-268°C, and the temperature outside the film bubble is 10-20°C lower than the temperature inside the film bubble; the formed film bubble is sequentially towed and wound through multiple groups of rollers, and the film is heated to 240-260°C again during the traction process to heat-treat the film. The technical solution provided by the present invention provides a method for producing polyetherimide film by a blow molding process, and the film bubble is blown out by the die head and then kept warm, so that the polyetherimide can be stably and continuously blown out, and in addition, due to the characteristics of the polyetherimide chain segments, the formed film is further heat-treated by adding a heating roller during the traction and winding process, which greatly improves the tensile properties and stability of the film.

Description

Technical Field

[0001] The invention belongs to the technical field of polyetherimide film production, and in particular relates to a melt blow molding process and a device for polyetherimide film. Background Art

[0002] Polyetherimide (PEI) is a type of polymer formed by introducing ether bonds into the polyimide (PI) chain. Amorphous polyetherimide is a super engineering plastic with high temperature resistance and dimensional stability, as well as chemical resistance, flame retardancy, electrical properties, high strength, high rigidity, etc. PEI resin can be widely used in high temperature resistant terminals, IC bases, lighting equipment, FPCB, liquid delivery equipment, aircraft internal parts, medical equipment and household appliances.

[0003] The glass transition temperature of PEI is 215℃, the heat deformation temperature is 200-225℃, and it can be used for a long time at 160-180℃, and the maximum intermittent use temperature is 200℃. However, this also means that the processing temperature of PEI material is relatively high, and its molding process is unique, which affects the promotion and application of PEI.

[0004] Thermoplastic film forming methods are generally cast film or blow molding, among which melt blow molding greatly reduces the cost of cast film and has uniform performance. Therefore, PEI melt blow molding has huge market prospects, but the process research of PEI melt blow molding has not been reported. Summary of the invention

[0005] The invention provides a melt blow molding process and a device for polyetherimide film, which are used to solve the problem that the current polyetherimide film cannot be formed by melt blow molding.

[0006] In order to solve the above technical problems, the technical solution of the present invention is: the melt blow molding process of the polyetherimide film comprises the following steps:

[0007] The raw materials are melted and extruded through a screw extruder, and then metered into a blow molding device;

[0008] In the blow molding equipment, the film bubble is blown out through the rotating die head, the die head temperature is 273-278℃, the temperature inside the film bubble is controlled at 260-268℃, and the temperature outside the film bubble is 10-20℃ lower than the temperature inside the film bubble;

[0009] The formed film bubble is pulled and rolled up in turn by multiple groups of rollers, and during the pulling process, it is heated again to 240-260°C to perform heat treatment on the film.

[0010] Optionally, the temperature of the screw extruder barrel is controlled in three stages from feeding to discharging, the first stage is controlled at 175-250°C, the second stage is controlled at 280-300°C, the third stage is controlled at 300-320°C, the system viscosity is controlled at 0.48-0.62dL / g, and the screw speed is controlled at 180-420r / min.

[0011] Optionally, during screw extrusion, the product is first filtered through a high-pressure filter and then metered, and the high-pressure filter has a pressure resistance of more than 50 MPa.

[0012] Optionally, the pressure of the rotary die head is 5-7kg.

[0013] Optionally, the temperature inside the film bubble and the temperature outside the film bubble are controlled by blowing in hot air.

[0014] Optionally, the hot air has an air path from bottom to top in the membrane bubble, then from top to bottom back to below the membrane bubble, through a channel to the outside of the membrane bubble, and then a blower causes it to run from bottom to top outside the membrane bubble, and finally escapes from the system.

[0015] The present invention also provides a melt blowing device for polyetherimide film, which includes a screw extruder, a filter connected to the nozzle of the screw extruder, a metering pump connected to the filter, a rotating die connected to the metering pump, a bubble stabilizing frame above the rotating die, an inner air duct arranged on the rotating die for supplying air to the inside of the film bubble, an air ring on the rotating die for supplying air to the outside of the film bubble, an insulation sleeve sleeved on the outside of the bubble stabilizing frame, a traction device located on the top of the bubble stabilizing frame, a winding device for winding the film, and a hot air blower connected to the air inlet of the inner air duct, wherein the hot air blower supplies hot air to the inner air duct.

[0016] Optionally, the air outlet of the inner air duct is located at 1 / 2 to 2 / 3 of the total height of the membrane bubble.

[0017] Optionally, the wind ring includes a main body, a central wind hole arranged in the center of the main body for setting an internal air duct, a channel arranged in the main body, and a guide fan arranged in the channel, the air inlet of the channel surrounds the periphery of the central wind hole and is located inside the membrane bubble, and the air outlet of the channel is located on the periphery of the membrane bubble.

[0018] Optionally, the thermal insulation sleeve comprises an inner thermal insulation sleeve and an outer thermal insulation sleeve which is sleeved outside the inner thermal insulation sleeve, and a region between the inner thermal insulation sleeve and the outer thermal insulation sleeve is evacuated.

[0019] Optionally, the traction device includes a herringbone plate, a traction roller, a heat treatment roller and a tensioning roller in the order of introducing the bubble.

[0020] Optionally, the heat setting rollers are composed of two pairs of electromagnetic rollers that press against each other.

[0021] The technical solution provided by the present invention provides a method for producing polyetherimide film by a blow molding process, which is mainly through suitable melt extrusion process conditions and a formable blown film process. Unlike the ordinary blown film process, which is cooled by air cooling or water cooling after extrusion from a die head, since the glass transition temperature of polyetherimide is very high, the polyetherimide can be stably and continuously blown out and formed by keeping the film bubble warm after blowing it out through the die head. In addition, due to the chain segment characteristics of the polyetherimide itself, the formed film is further heat treated by adding a heating roller during the traction and winding process, which greatly improves the tensile properties and stability of the film. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of a specific embodiment of the melt blowing device of the polyetherimide film of the present invention;

[0023] Figure 2 It is a structural schematic diagram of a specific implementation mode of the air ring of the present invention.

[0024] As shown in the figure:

[0025] 01-film bubble, 10-screw extruder, 20-filter, 30-metering pump, 41-rotating die head, 42-bubble stabilizing frame, 51-inner air duct, 52-hot air blower, 60-air ring, 61-main body, 62-center air hole, 63-channel, 64-guide fan, 70-insulation sleeve, 71-inner insulation sleeve, 72-outer insulation sleeve, 80-traction device, 81-herringbone plate, 82-traction roller, 83-heat treatment roller, 84-tensioning roller, 90-winding device. DETAILED DESCRIPTION

[0026] For ease of understanding, the melt blow molding process and device of the polyetherimide film are described below in conjunction with embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0027] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation and positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0028] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] like Figure 1 As shown, a melt blow molding device for polyetherimide film includes a screw extruder 10, a filter 20 connected to the nozzle of the screw extruder 10, a metering pump 30 connected to the filter 20, a rotary die 41 connected to the metering pump 30, a bubble stabilizing frame 42 above the rotary die 41, an internal air duct 51 arranged on the rotary die 41 for supplying air to the inside of the film bubble 01, an air ring 60 above the rotary die 41 for supplying air to the outside of the film bubble 01, a heat preservation sleeve 70 sleeved on the outside of the bubble stabilizing frame 42, a traction device 80 located on the top of the bubble stabilizing frame 42 and a winding device 90 for winding up the film.

[0030] Continue to see Figure 1 The air inlet of the inner air duct 51 is connected to a hot air blower 52, and the hot air blower 52 supplies hot air to the inner air duct 51. The air outlet of the inner air duct 51 is located at about 2 / 3 of the total height of the film bubble 01.

[0031] Continue to see Figure 1 and 2 The wind ring 60 includes a main body 61, a central wind hole 62 arranged at the center of the main body 61 for setting the internal wind duct 51, a channel 63 arranged in the main body 61, and a guide fan 64 arranged in the channel 63. The air inlet of the channel 63 surrounds the periphery of the central wind hole 62 and is located inside the membrane bubble 01, and the air outlet of the channel 63 is located on the periphery of the membrane bubble 01.

[0032] Continue to see Figure 1 The insulation cover 70 includes an inner insulation cover 71 and an outer insulation cover 72 which is sleeved outside the inner insulation cover 71, and the area between the inner insulation cover 71 and the outer insulation cover 72 is evacuated. The insulation cover 70 can, on the one hand, insulate the film bubble so that the film bubble can be formed at a relatively high temperature, and on the other hand, prevent the high temperature in the film bubble from causing danger and injury to the operator.

[0033] Continue to see Figure 1 The traction device 80 includes a herringbone plate 81, a traction roller 82, a heat treatment roller 83 and a tension roller 84 in the order of the film bubble 01 introduction. The traction roller 82 is composed of two rollers abutting against each other, the heat setting roller 83 is composed of two pairs of electromagnetic rollers that squeeze each other, and the tension roller 84 is composed of three rollers that are arranged in sequence by up and down offset.

[0034] The process of using the above-mentioned polyetherimide film melt blowing device to carry out polyetherimide blow molding is as follows:

[0035] S1: Polyetherimide and other additives are mixed and fed into a screw extruder 10. The temperature of the barrel of the screw extruder 10 is controlled in three stages from feeding to discharging. The temperature of the first stage is controlled at 200°C, the temperature of the second stage is controlled at 275°C, and the temperature of the third stage is controlled at 310°C. The viscosity of the system is controlled at 0.56dL / g, and the screw speed is controlled at 300r / min. After melt extrusion, it passes through a high-pressure filter 20 with a pressure resistance of more than 50MPa, and then is stably fed into a rotating die head 40 after being metered by a metering pump 30.

[0036] S2: The film bubble is blown out through the rotating die head 40, the temperature of the rotating die head 40 is controlled at about 275°C, and the pressure is about 6kg. The hot air blower 52 is used to supply heat to the inner air duct 51, and the temperature inside the film bubble is controlled at about 265°C. The guide fan 64 drives the internal circulation of the hot air, and the hot air enters the area between the outside of the film bubble and the insulation sleeve 70 from the air outlet of the channel 63. The temperature difference between the inside and outside of the film bubble is about 15°C, that is, the temperature outside the film bubble is about 250°C; the air path of the hot air is from bottom to top in the film bubble, and then from top to bottom back to below the film bubble, through the channel to the outside of the film bubble, and then the blower makes it run from bottom to top outside the film bubble, and finally escapes from the system.

[0037] S3: The formed film bubble is sequentially pulled, heat treated and rolled up by multiple groups of rollers to obtain a blow-molded polyetherimide film.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the above embodiments, a person skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A melt blow molding process for polyetherimide film, characterized in that: The steps include: The raw materials are melted and extruded through a screw extruder, and then metered into a blow molding device; In the blow molding equipment, the film bubble is blown out through the rotating die head, the die head temperature is 273-278℃, the temperature inside the film bubble is controlled at 260-268℃, and the temperature outside the film bubble is 10-20℃ lower than the temperature inside the film bubble; The formed film bubble is pulled and rolled up by multiple groups of rollers in turn, and is heated again to 240-260℃ during the pulling process to heat treat the film; The temperature inside the film bubble and the temperature outside the film bubble are controlled by blowing in hot air; The hot air has an air path from bottom to top in the membrane bubble, and then returns from top to bottom to below the membrane bubble, passes through a channel to the outside of the membrane bubble, and is then caused to run from bottom to top outside the membrane bubble by a blower, and finally escapes from the system.

2. The melt blow molding process of polyetherimide film according to claim 1, characterized in that: The temperature of the screw extruder barrel is controlled in three stages from feeding to discharging, the first stage is controlled at 175-250°C, the second stage is controlled at 280-300°C, and the third stage is controlled at 300-320°C. The system viscosity is controlled at 0.48-0.62dL / g, and the screw speed is controlled at 180-420r / min.

3. The melt blow molding process of polyetherimide film according to claim 1, characterized in that: When extruded by a screw, the material is first filtered through a high-pressure filter and then metered. The high-pressure filter has a pressure resistance of more than 50 MPa.

4. The melt blow molding process of polyetherimide film according to claim 1, characterized in that: The pressure of the rotary die head is 5-7kg.

5. A melt blowing device for polyetherimide film, characterized in that: It includes a screw extruder, a filter connected to the nozzle of the screw extruder, a metering pump connected to the filter, a rotating die connected to the metering pump, a bubble stabilizing frame above the rotating die, an inner air duct arranged on the rotating die to supply air to the inside of the film bubble, an air ring on the rotating die to supply air to the outside of the film bubble, a heat preservation sleeve sleeved outside the bubble stabilizing frame, a traction device located on the top of the bubble stabilizing frame, a winding device for winding up the film, and a hot air blower connected to the air inlet of the inner air duct, wherein the hot air blower supplies hot air to the inner air duct; The wind ring includes a main body, a central wind hole arranged in the center of the main body for setting an internal wind duct, a channel arranged in the main body, and a guide fan arranged in the channel. The air inlet of the channel surrounds the periphery of the central wind hole and is located inside the membrane bubble, and the air outlet of the channel is located on the periphery of the membrane bubble.

6. The melt-blowing device for polyetherimide film according to claim 5, characterized in that: The air outlet of the inner air duct is located at 1 / 2 to 2 / 3 of the total height of the membrane bubble.

7. The melt-blowing device for polyetherimide film according to claim 5, characterized in that: The thermal insulation sleeve comprises an inner thermal insulation sleeve and an outer thermal insulation sleeve which is sleeved outside the inner thermal insulation sleeve, and the area between the inner thermal insulation sleeve and the outer thermal insulation sleeve is evacuated.

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