CN114654628A

CN114654628A - Heat setting temperature raising unit and method for film stretching oven

Info

Publication number: CN114654628A
Application number: CN202210269842.1A
Authority: CN
Inventors: 汤智勇; 梁达辉; 何汉昭
Original assignee: Mce Stretching Industry Co ltd
Current assignee: Mce Stretching Industry Co ltd
Priority date: 2022-03-18
Filing date: 2022-03-18
Publication date: 2022-06-24

Abstract

The invention relates to a heat setting temperature raising unit and a heat setting temperature raising method for a film stretching oven. In addition, the film does not need to be heated quickly by increasing the flow of hot air as in the traditional technology, so that the physical deformation of the film can be avoided, and the processing quality of the film can be ensured. In addition, when the film enters the heat setting section, the temperature of the film can be accurately adjusted at the initial part of the heat setting section in a hot air heating mode, and the temperature of the film is controlled at the third process temperature at the rest parts of the heat setting section. Secondly, the heating section is located between stretching section and the heat setting section, can play the effect of keeping apart stretching section and heat setting section for the inside hot-blast and the inside hot-blast as far as of heat setting section of stretching section separate, avoid mutual interference, improved stability promptly.

Description

Heat setting temperature raising unit and method for film stretching oven

Technical Field

The invention relates to the technical field of film stretching, in particular to a heat setting temperature raising unit and a heat setting temperature raising method for a film stretching oven.

Background

The film stretching device is formed by combining a plurality of relatively independent functional sections with certain temperature difference, and the technological processes of preheating, stretching, heat setting, cooling and the like are respectively completed in each functional section from the inlet to the outlet of the oven under the traction of the chain clamps along the line on the two sides of the film.

Because the film is generally high to the temperature precision, the high temperature oven is generally adopted the accurate hot-blast conduction mode of accuse temperature to the heating of film, heats its inside air through independent hot-blast return circuit in every oven unit of functional section promptly and obtains the hot-air, carries out the contact heating by the hot-air to the film surface again to constitute a plurality of stable hot-blast return circuits and guarantee the homogeneity of temperature: the method comprises the following steps of backflow air, a heater, a centrifugal fan, hot air distribution, a static pressure box (nozzle), film heat exchange, internal space return, a return air suction opening and the next circulation.

Although the process temperatures of different films are different, the films need to enter a heat setting section for heat setting treatment at higher temperature after being stretched and expanded by a stretching section, so that the stress between macromolecules is released to realize the stability of the films, or the materials are cured. The process temperature rise of a considerable part of the film material heat setting section relative to the stretching section can reach more than 100 degrees. In order to avoid the mutual influence between the oven unit of the heat setting section and the oven unit of the stretching section, a buffer section needs to be arranged between the heat setting section and the stretching section, and the hot air mutual interference between the heat setting section and the stretching section is avoided through the buffer section. The buffer section does not impose any target temperature restriction on the film, the temperature of the film is usually in a relatively natural drifting state, the front section of the film entering the heat setting section is gradually heated to the heat setting temperature and kept for a period of time, and finally the film is restored to the normal temperature state under the action of the cooling area.

Disclosure of Invention

In view of the above, there is a need to overcome the defects of the prior art and to provide a heat-setting temperature raising unit and method for a film stretching oven, which can improve the heating efficiency and ensure the processing quality of the film.

The technical scheme is as follows: a heat-set temperature raising unit of a film stretching oven, comprising: the film heating device comprises a stretching section, a heating section and a heat setting section, wherein the stretching section, the heating section and the heat setting section are sequentially arranged along the running direction of a film, the stretching section is used for heating the film and controlling the temperature of the film to be at a first process temperature, the heating section is provided with an electromagnetic radiation heater, the electromagnetic radiation heater is used for heating the film to a second process temperature, and the heat setting section is used for heating the film and controlling the film to be at a third process temperature; the first process temperature, the second process temperature and the third process temperature are defined as t1, t2 and t3, respectively; t1< t2, t2 is 0.9t3 to 1.1t 3.

In one embodiment, the electromagnetic radiation heater comprises a reflective enclosure and at least one infrared element disposed on the reflective enclosure, the infrared element facing the film; the infrared elements project onto the film in a direction perpendicular to the film across opposite sides of the film; the infrared element is an infrared lamp tube and/or an infrared plate.

In one embodiment, the heat setting temperature raising unit of the film stretching oven further comprises a track passing through the stretching section, the heating section and the heat setting section in sequence, and a chain clamp assembly running along the track; the chain clamp assembly is used for clamping the side part of the film so as to drive the film to run;

the heating section further comprises a hot air circulating mechanism, and the hot air circulating mechanism is used for blowing hot air to the chain clamp assembly and the film side portion of the heating section.

In one embodiment, the hot air circulation mechanism comprises a wind shielding structure, an air inlet pipe and an air return pipe; the wind shielding structure and the rail are enclosed to form a hot air channel, and the chain clamp assembly is movably arranged in the hot air channel in a penetrating mode; the air inlet pipe and the air return pipe are communicated with the hot air channel, the air inlet pipe is used for introducing hot air into the hot air channel, and the air return pipe is used for recovering the hot air in the hot air channel.

In one embodiment, the wind shielding structure comprises a first wind shielding plate and a second wind shielding plate; the first wind shield and the second wind shield are arranged at intervals up and down to form a first gap through which the film penetrates, the first wind shield and the second wind shield are arranged at intervals with the chain clamp assembly, and the first wind shield, the second wind shield and the rail are enclosed to form a hot air channel.

In one embodiment, the air inlet pipe is arranged at one end of the hot air channel close to the heat setting section, and the air return pipe is arranged at one end of the hot air channel close to the stretching section.

In one embodiment, the arrangement direction of the air inlet pipe forms an included angle with the running direction of the film; the included angle between the air inlet pipe and the running direction of the film is defined as a, and a is less than 90 degrees.

In one embodiment, the heating section is provided with two partition plates at two opposite ends along the running direction of the film; the partition plate is provided with a window through which the track, the chain clamp assembly and the film pass, and a wind shielding part is arranged on the wall of the window.

In one embodiment, each wind shielding member comprises a first wind curtain and a second wind curtain which are arranged on the wall of the window opening at intervals up and down, and a second gap for the thin film to pass through is formed between the first wind curtain and the second wind curtain.

A film stretching method adopts a heat setting temperature lifting unit of the film stretching oven, and comprises the following steps:

the method comprises the following steps that a film enters a stretching section, the film in the stretching section is heated through a hot air loop in the stretching section in the stretching process of the film in the stretching section, and the temperature of the film is controlled to be at a first process temperature;

the film enters the heating section from the stretching section, and the film positioned in the heating section is heated by the electromagnetic radiation heater, so that the film is heated from the first process temperature to the second process temperature;

the film enters the heat setting section from the heating section, and the film in the heat setting section is subjected to heat exchange through a hot air loop in the heat setting section, so that the film is adjusted to a third process temperature from the second process temperature.

The heating section is additionally arranged between the stretching section and the heat setting section, the heating section heats the film by adopting the heating mode of the electromagnetic radiation heater, the temperature of the film can be rapidly increased to the second process temperature, and the heating efficiency is greatly improved compared with the traditional hot air heating mode. In addition, the film does not need to be heated quickly by increasing the flow of hot air as in the traditional technology, so that the physical deformation of the film can be avoided, and the processing quality of the film can be ensured. In addition, t2 is 0.9t3 to 1.1t3, namely the heating section can heat the film to be close to the third process temperature, so that when the film enters the heat setting section, the temperature of the film can be accurately adjusted at the initial part of the heat setting section in a hot air heating mode, and the temperature of the film is controlled at the third process temperature at the rest parts of the heat setting section. Secondly, the heating section is located between stretching section and the heat setting section, can play the effect of keeping apart stretching section and heat setting section for the inside hot-blast and the inside hot-blast as far as of heat setting section of stretching section separate, avoid mutual interference, improved stability promptly. Thirdly, the length of the heat setting section is only related to the setting process, and the compensation lengthening of the interference of the actual heat efficiency factor of the film is eliminated.

According to the film stretching method, the heating section is additionally arranged between the stretching section and the heat setting section, the heating section adopts the heating mode of the electromagnetic radiation heater to heat the film, the temperature of the film can be rapidly increased to the second process temperature, and the heating efficiency is greatly improved compared with the traditional hot air heating mode. In addition, the film does not need to be heated quickly by increasing the flow of hot air as in the traditional technology, so that the physical deformation of the film can be avoided, and the processing quality of the film can be ensured. In addition, t2 is 0.9t3 to 1.1t3, namely the heating section can heat the film to be close to the third process temperature, so that when the film enters the heat setting section, the temperature of the film can be accurately adjusted at the initial part of the heat setting section in a hot air heating mode, and the temperature of the film is controlled at the third process temperature at the rest parts of the heat setting section. Secondly, the heating section is located between stretching section and the heat setting section, can play the effect of keeping apart stretching section and heat setting section for the inside hot-blast and the inside hot-blast as far as of heat setting section of stretching section separate, avoid mutual interference, improved stability promptly. Thirdly, the length of the heat setting section is only related to the setting process, and the compensation lengthening of the interference of the actual heat efficiency factor of the film is eliminated.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification.

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic structural view of a heat-setting temperature raising unit of a film stretching oven according to an embodiment of the present invention;

FIG. 2 is a schematic perspective view of a heating section according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a heating section according to an embodiment of the present invention;

FIG. 4 is a schematic view of the structure of FIG. 3 after the EM heater is hidden;

FIG. 5 is a schematic bottom view of the heating section of the configuration shown in FIG. 3;

FIG. 6 is a schematic cross-sectional view at A-A of FIG. 5;

FIG. 7 is an enlarged view of FIG. 6 at B;

fig. 8 is a schematic structural diagram of a hot air circuit according to an embodiment of the present invention.

L1, preheating section; l2, stretch section; l3, heating section; l4, heat setting section; l5, buffer segment; l6, cooling section; 10. a film; 20. an electromagnetic radiation heater; 21. a reflector; 22. an infrared element; 30. a track; 40. a chain clamp assembly; 50. a hot air circulating mechanism; 51. a first windshield; 52. a second wind deflector; 53. an air inlet pipe; 54. a return air duct; 55. a hot air passage; 56. a first gap; 60. a partition plate; 61. a window; 62. a wind shielding member; 621. a first air curtain; 622. a second air curtain; 623. a second gap; 70. a hot air circuit; 71. a fan; 72. a dispenser; 73. a first blast pipe; 74. a second blast pipe; 75. a first air suction pipe; 76. a second aspiration channel; 77. a first temperature increasing device; 78. a second temperature increasing device; 80. an oven unit; 90. a housing; 91. side plates.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, as those skilled in the art will recognize without departing from the spirit and scope of the present invention.

Based on the traditional technology, when the film with relatively low temperature enters the heat setting section with relatively high temperature from the buffer section, the film is heated to the setting process temperature in a hot air conduction mode by setting a long section of stroke in the heat setting section. In addition, because the efficiency of hot air conduction heating is not high, the hot air output (speed) is increased at the initial section of the heat setting section to act on the film material, so that the core layer of the film and the surface layer reach the setting process temperature quickly. On the one hand, however, the increase of the hot air output in the initial section of the heat setting section can easily cause a serious air channeling phenomenon among the oven units in the initial section, and affect the stability of the temperature fields of each other. On the other hand, since a part of the film is very thin (3 μm to 5 μm) after being stretched at a high magnification in the stretching section, the external stretching tension is eliminated with the completion of the stretching process, and the film is in the weakest state before heat setting, and the high-speed air flow at the initial stage of the heat setting section easily causes plastic deformation of the film.

Based on this, referring to fig. 1 to 3, fig. 1 shows a schematic structural view of a heat-setting temperature raising unit of a film stretching oven according to an embodiment of the present invention, fig. 2 shows a schematic perspective structural view of a heating section L3 according to an embodiment of the present invention, and fig. 3 shows a schematic structural view of a heating section L3 according to an embodiment of the present invention. The heat setting temperature raising unit of the film stretching oven provided by the embodiment of the invention comprises a stretching section L2, a heating section L3 and a heat setting section L4. The stretching stage L2, the heating stage L3, and the heat setting stage L4 are arranged in sequence along the running direction of the film 10 (the scheme shown by the x-axis in fig. 1). The stretching section L2 is used to heat the film 10 to the first process temperature, and the heating section L3 is provided with an electromagnetic radiation heater 20. Electromagnetic radiation heater 20 is used to heat film 10 to the second process temperature. The heat setting section L4 is used to heat the film 10 and control the film 10 at the third process temperature. The first process temperature, the second process temperature and the third process temperature are respectively defined as t1, t2 and t 3; t1< t2, t2 is 0.9t3 to 1.1t 3.

According to the heat setting temperature lifting unit of the film stretching oven, the heating section L3 is additionally arranged between the stretching section L2 and the heat setting section L4, the heating section L3 adopts the heating mode of the electromagnetic radiation heater 20 to heat the film 10, the temperature of the film 10 can be quickly raised to the second process temperature, and the heating efficiency is greatly improved compared with the traditional hot air heating mode. In addition, since it is not necessary to rapidly heat the film 10 by increasing the flow rate of hot air as in the conventional art, the physical deformation of the film 10 can be prevented, and thus the processing quality of the film 10 can be ensured. In addition, since t2 is 0.9t3 to 1.1t3, that is, the heating section L3 can already heat the film 10 to a temperature close to the third process temperature, when the film 10 enters the heat setting section L4, the temperature of the film 10 can be precisely adjusted at the initial part of the heat setting section L4 by hot air heating, and the temperature of the film 10 is controlled at the third process temperature at the rest of the heat setting section L4. Secondly, heating section L3 is located between stretch section L2 and heat setting section L4, can play the effect of keeping apart stretch section L2 and heat setting section L4 for the inside hot-blast of stretch section L2 separates as far as possible with the inside hot-blast of heat setting section L4, avoids mutual interference, has improved stability promptly. Again, the length of the heat setting stage L4 is only associated with the setting process, eliminating the compensating lengthening that interferes with the actual thermal performance factors of the film 10.

It should be noted that the first process temperature, the second process temperature, and the third process temperature are flexibly adjusted and set according to the actually processed film material, and are not limited herein. As an example, the first process temperature is 230 to 260, the second process temperature is 350 to 370, and the third process temperature is 370 to 380.

In one embodiment, t2 ≧ 0.95t3, t2 includes, but is not limited to, 0.95t3, 0.96t3, 0.97t3, 0.98t3, 0.99t3, t 3.

Alternatively, in order to ensure the heating effect of the electromagnetic radiation heater 20 on the film 10, the wavelength of the electromagnetic radiation heater 20 is configured to be adapted to the molecules of the heated material.

Referring to fig. 2 and 3, in one embodiment, the electromagnetic radiation heater 20 includes a reflector 21 and at least one infrared element 22 disposed on the reflector 21. An infrared element 22 is directed toward the film 10. Thus, when the electromagnetic radiation heater 20 is operated, the infrared element 22 emits infrared light toward the thin film 10, thereby raising the temperature of the thin film 10 to the second process temperature. In addition, the reflective cover 21 reflects infrared light of the infrared element 22, and improves the heating effect of the infrared element 22. Optionally, the infrared element 22 includes, but is not limited to, an infrared lamp tube and/or an infrared plate, which are selected and arranged according to actual requirements, and is not limited herein.

Referring to fig. 2 and 3, in one embodiment, the infrared elements 22 project onto the film 10 in a direction perpendicular to the surface of the film 10 across opposite sides of the film 10.

Referring to fig. 2 and 3, in one embodiment, there are at least two infrared elements 22, and all the infrared elements 22 are sequentially spaced along the running direction of the film 10. Thus, as the film 10 travels through the heating section L3, various portions of the film 10, including the transverse direction (as indicated by the y-axis in FIG. 1) and the longitudinal direction (as indicated by the x-axis in FIG. 1), as well as the skin and core layers, are better heated; in addition, the temperature of the film 10 may gradually increase as it moves through heating section L3, reaching the second process temperature as the film 10 exits heating section L3.

Alternatively, the electromagnetic radiation heater 20 may be disposed at intervals directly above the film 10, and emit infrared light to the upper surface of the film 10 from above to heat the entire film 10; the electromagnetic radiation heater 20 may be disposed at an interval just below the film 10, and emit infrared light from below to the lower surface of the film 10 to heat the entire film 10.

Referring to fig. 2 to 4, in one embodiment, the heat setting temperature raising unit of the film stretching oven further includes a rail 30 passing through the stretching section L2, the heating section L3, and the heat setting section L4 in sequence, and a chain clip assembly 40 running along the rail 30. The chain gripper assembly 40 is used to grip the side of the film 10 to drive the film 10 in operation.

Referring to fig. 5-7, in one embodiment, heating section L3 further includes hot air circulation mechanism 50. The hot air circulating mechanism 50 blows hot air to the chain nip assembly 40 and the side of the film 10 at the heating stage L3. As described above, generally, the electromagnetic radiation heater 20 can heat all the portions of the film 10 by means of infrared light, but cannot directly heat the metal chain clip assembly 40, and the chain clip assembly 40 absorbs heat from the side portions of the film 10 while clamping the side portions of the film 10, so that the temperature of the side portions of the film 10 is relatively lower than that of the middle portion of the film 10. After hot air is blown to the chain clamp assembly 40 located in the heating section L3 by the hot air circulating mechanism 50, the hot air circulating mechanism 50 heats the chain clamp assembly 40 by means of hot air contacting the chain clamp assembly 40, so that the temperature of the side portion of the film 10 can be raised to the second process temperature, and the processing quality of the film 10 can be ensured.

Referring to fig. 5 to 7, two chain clip assemblies 40 and two rails 30 are provided, and the two chain clip assemblies 40 are disposed on the two rails 30 in a one-to-one correspondence manner. One of the chain gripper assemblies 40 is for gripping one of the sides of the film 10 and the other chain gripper assembly 40 is for gripping the other side of the film 10. Correspondingly, there are two hot air circulating mechanisms 50, and the two hot air circulating mechanisms 50 are arranged in one-to-one correspondence with the two chain clamp assemblies 40. Thus, the two hot air circulating mechanisms 50 can respectively and synchronously heat the two chain clamp assemblies 40, and can ensure that the temperatures of the two opposite sides of the film 10 are all increased to the second process temperature, so that the processing quality of the film 10 can be ensured.

Referring to fig. 5 to 7, in one embodiment, the hot air circulating mechanism 50 includes a wind shielding structure, an air inlet pipe 53 and an air return pipe 54. The wind shielding structure and the rail 30 enclose to form a hot air channel 55, and the chain clamp assembly 40 is movably arranged in the hot air channel 55 in a penetrating way. The air inlet pipe 53 and the air return pipe 54 are both communicated with the hot air channel 55, the air inlet pipe 53 is used for introducing hot air into the hot air channel 55, and the air return pipe 54 is used for recovering the hot air in the hot air channel 55. Therefore, when the hot air recovery device works, hot air enters the hot air channel 55 through the air inlet pipe 53, the hot air correspondingly heats the chain clamp assembly 40 in the process of contacting the chain clamp assembly 40, and the hot air after heat exchange with the chain clamp assembly 40 is recovered through the air return pipe 54.

Referring to fig. 5 to 7, in one embodiment, the wind shielding structure includes a first wind shield 51 and/or a second wind shield 52. The first wind deflector 51 and the second wind deflector 52 are vertically spaced to form a first gap 56 (as shown in fig. 7) through which the film 10 passes, the first wind deflector 51 and the second wind deflector 52 are both spaced from the chain clamp assembly 40, and the first wind deflector 51, the second wind deflector 52 and the rail 30 enclose to form a hot air channel 55. In this way, as the first wind deflector 51, the second wind deflector 52 and the rail 30 enclose and form the hot air channel 55, hot air entering the hot air channel 55 can fully contact and heat the chain clamp assembly 40, so that the hot air heating effect on the chain clamp assembly 40 is better; in addition, the first wind deflector 51 and the second wind deflector 52 have an isolation function, that is, the hot wind in the hot wind channel 55 only heats the chain clamp assembly 40 and the side portions of the film 10, and basically does not enter the middle area of the film 10, that is, does not heat the middle portion of the film 10, so that the heating effect on the side portions of the film 10 can be ensured.

It should be noted that, in order to heat the side portion of the film 10 to the second process temperature, the temperature of the hot air introduced through the air inlet pipe 53 is flexibly adjusted and set according to the second process temperature, as long as the side portion of the film 10 is heated to the second process temperature.

Referring to fig. 5 to 7, in an embodiment, in order to improve the tightness of the hot air channel 55 formed by the first wind deflector 51, the second wind deflector 52 and the rail 30, the first wind deflector 51 and the second wind deflector 52 are all set to have an L shape, an arc shape, or the like, and may be regular or irregular.

Referring to fig. 1 and 2, in one embodiment, the air inlet pipe 53 is disposed at an end of the hot air channel 55 close to the heat setting section L4, and the air return pipe 54 is disposed at an end of the hot air channel 55 close to the stretching section L2. In this manner, the temperature of the hot air inside the hot air passage 55 gradually increases from the end close to the stretching section L2 to the end close to the heat setting section L4, thereby being capable of facilitating the hot air inside the hot air passage 55 to gradually increase the temperature of the side of the film 10 to the second process temperature. In addition, the hot air can be ensured to flow in the whole hot air channel 55, so that the heating effect on the side part of the film 10 and the chain clamp assembly 40 is better.

As an alternative, the air inlet pipe 53 and the air return pipe 54 may also be communicated with the hot air channel 55 in other arrangements, and are flexibly set and adjusted according to actual requirements, which is not limited herein.

Referring to fig. 5, in one embodiment, the air inlet pipe 53 is disposed at an angle to the running direction of the film 10; the angle between the air inlet duct 53 and the direction of travel of the film 10 is defined as a, a <90 °. As one example, a ≦ 60 °, including but not limited to 45 °, 30 °, 25 °, 20 °, 15 °, 10 °, 5 °, and so forth. Thus, the air inlet pipe 53 can smoothly introduce hot air into the hot air passage 55, and the hot air introduced into the hot air passage 55 exchanges heat with the chain clip assembly 40 and the side portion of the film 10, and is then recovered by the return air pipe 54.

In one embodiment, the air inlet pipe 53 may be connected to a separate hot air source, that is, hot air is fed into the hot air passage 55 through the air inlet pipe 53 by the separate hot air source; accordingly, the return duct 54 circulates the hot air inside the hot air passage 55 to the separate hot air source, heats the recovered hot air to a preset temperature by the separate hot air source, and then delivers the heated hot air to the intake duct 53.

In another embodiment, the air inlet duct 53 may also be connected to the hot air supply inside the heat setting section L4 through a duct, that is, by feeding a portion of the hot air supply inside the heat setting section L4 through the air inlet duct 53 into the hot air passageway 55. Correspondingly, the return air duct 54 directly discharges the hot air in the hot air channel 55 to the outside, and the hot air can also be circulated to the inside of the heat setting section L4, and the heat setting section L4 heats the recovered hot air to a preset temperature.

It should be noted that, the air inlet pipe 53 is connected to the first wind deflector 51 or the second wind deflector 52, and the "air inlet pipe 53" may be a part of the "first wind deflector 51 or the second wind deflector 52", that is, the "air inlet pipe 53" and the "other part of the first wind deflector 51 or the second wind deflector 52" are integrally formed; or a separate member which is separable from the other portion of the first wind deflector 51 or the second wind deflector 52, that is, the "air inlet duct 53" may be separately manufactured and then integrated with the other portion of the first wind deflector 51 or the second wind deflector 52.

It should be noted that the return duct 54 is connected to the first wind deflector 51 or the second wind deflector 52, and the "return duct 54" may be a part of the "first wind deflector 51 or the second wind deflector 52", that is, the "return duct 54" and the "other part of the first wind deflector 51 or the second wind deflector 52" are integrally formed; or a separate component which can be separated from the other parts of the first wind deflector 51 or the second wind deflector 52, that is, the "return air pipe 54" can be manufactured separately and then combined with the other parts of the first wind deflector 51 or the second wind deflector 52 into a whole.

Referring to fig. 2 and 4, in one embodiment, partitions 60 are disposed at opposite ends of the heating section L3 along the direction of travel of the film 10. The partition 60 is provided with a window 61 for the rail 30, the chain clamp assembly 40 and the film 10 to pass through, and a wind shielding member 62 is provided on the wall of the window 61. Thus, the wind shielding piece 62 at one end of the heating section L3 can prevent the hot air in the stretching section L2 from entering the heating section L3 through the window 61 cross flow as much as possible, and the wind shielding piece 62 at the other end of the heating section L3 can prevent the hot air in the heat setting section L4 from entering the heating section L3 through the window 61 cross flow as much as possible, so that the hot air in the stretching section L2 and the hot air in the heat setting section L4 are completely isolated from each other, the hot air in the stretching section L2 and the hot air in the heat setting section L4 are prevented from mutual cross flow influence, and the processing quality of the film 10 is ensured.

Referring to fig. 2 and 4, in one embodiment, each wind shielding member 62 includes a first wind curtain 621 and a second wind curtain 622 that are disposed on the opening wall of the window 61 at an interval from top to bottom, and the first wind curtain 621 and the second wind curtain 622 form a second gap 623 (as shown in fig. 4) for the film 10 to pass through. Thus, the first air curtain 621 and the second air curtain 622 are adopted to keep out the wind, so that a good wind-shielding isolation effect can be ensured, and meanwhile, the damage to the film 10 is small. Specifically, the first air curtain 621 and the second air curtain 622 are made of a high temperature resistant non-metal material and/or a metal material, including but not limited to silicone, rubber, resin, and plastic.

Referring to fig. 1 and 2, in one embodiment, the heat-setting temperature raising unit of the film stretching oven further includes a preheating section L1, a buffering section L5, and a cooling section L6. The preheating stage L1, stretching stage L2, heating stage L3, heat setting stage L4, buffer stage L5, and cooling stage L6 are arranged in series in the running direction of the film 10 (as shown by the scheme of the x-axis in fig. 1). The preheating stage L1 uses a hot air loop 70 to provide hot air to heat the film 10 in the preheating stage L1, so as to heat the film 10 to a fourth process temperature. The buffer section L5 is arranged between the heat setting section L4 and the cooling section L6, plays a role in buffering, and can avoid the mutual cross flow influence between the heat setting section L4 and the cooling section L6. The cooling stage L6 cools the film 10 down to room temperature.

Referring to fig. 1, the preheating section L1, the stretching section L2, the heat setting section L4, the buffer section L5 and the cooling section L6 all include at least two oven units 80 sequentially connected in series along the longitudinal direction (the direction indicated by the x axis). The process temperature of each oven unit 80 can be flexibly adjusted and set according to actual requirements as long as the process temperature is satisfied. In addition, any two adjacent oven units 80 are separated by the partition plate 60, so that the independence of the oven units 80 is improved, the temperature of each oven unit 80 is favorably controlled, and meanwhile, the phenomenon of hot air channeling interference among the oven units 80 can be avoided.

In addition, the heat-setting temperature raising unit of the film stretching oven further includes a housing 90 disposed along the running direction of the film 10. The enclosure 90 extends from the head end of the preheat section L1 to the end of the cool section L6. The track 30, chain clamp assembly 40 and film 10 are all disposed within the housing 90. The housing 90 provides a relatively closed environment, which can ensure the processing quality of the film 10, and can collect hot air to recycle the hot air, thereby preventing the hot air from being discharged to the environment. Specifically, the housing 90 includes a top plate (hidden in the drawing and not shown) and a bottom plate (hidden in the drawing and not shown) which are oppositely disposed, and two side plates 91 which are oppositely disposed, and the top plate is connected to the bottom plate through the two side plates 91.

Referring to fig. 8, fig. 8 is a schematic structural diagram of a hot air circuit 70 according to an embodiment of the invention. In one embodiment, the hot air circuit 70 includes a blower 71, a distributor 72, a first air supply pipe 73, a second air supply pipe 74, a first air suction pipe 75, a second air suction pipe 76, a first temperature increasing device 77 disposed on the first air suction pipe 75, and a second temperature increasing device 78 disposed on the second air suction pipe 76. The fan 71 supplies power to output the hot air in the distributor 72 to the first air supply pipe 73 and the second air supply pipe 74, and the first air supply pipe 73 and the second air supply pipe 74 are respectively located at the upper side and the lower side of the film 10 and are respectively used for blowing the hot air to the upper side and the lower side of the film 10. The first air suction pipe 75 and the second air suction pipe 76 are respectively located at the upper side and the lower side of the film 10, and are used for conducting hot air back suction treatment after heat exchange with the film 10 and sending the hot air back to the distributor 72, meanwhile, the return air of the first air suction pipe 75 is heated through the first temperature rising device 77 to supplement heat loss, and the return air of the second air suction pipe 76 is heated through the second temperature rising device 78 to supplement heat loss.

Referring to fig. 1 to 3, in one embodiment, a film stretching method using the heat setting temperature raising unit of the film stretching oven of any one of the above embodiments includes the following steps:

step S100, the film 10 enters a stretching section L2, the film 10 inside the stretching section L2 is heated through a hot air loop 70 inside the stretching section L2 in the process that the film 10 is stretched in the stretching section L2, and the film 10 is controlled to reach a first process temperature;

step S200, the film 10 enters a heating section L3 from the stretching section L2, and the film 10 positioned in the heating section L3 is heated by an electromagnetic radiation heater 20, so that the film 10 is heated from the first process temperature to the second process temperature;

step S300, the film 10 enters the heat setting section L4 from the heating section L3, and the heat exchange is performed on the film 10 located inside the heat setting section L4 through the hot air loop 70 inside the heat setting section L4, so that the film 10 is adjusted from the second process temperature to the third process temperature.

In step S300, after the film 10 enters the heat setting section L4, the heat setting section L4 heats the film 10 by means of the circulating hot air provided by the hot air circuit 70 contacting the film 10, so as to precisely correct the temperature of the film 10 relative to the heat radiation heating of the film 10 by the electromagnetic radiation heater, and precisely adjust the temperature of the film 10 from the second process temperature to the third process temperature. That is, when the second process temperature is lower than the third process temperature, the temperature of the thin film 10 is heated to the third process temperature; when the second process temperature is greater than the third process temperature, the temperature of the film 10 is lowered to the third process temperature. And because the second process temperature is relatively close to the third process temperature, the heat setting section L4 can quickly and efficiently adjust the film 10 from the second process temperature to the third process temperature.

In the film stretching method, the heating section L3 is additionally arranged between the stretching section L2 and the heat setting section L4, the heating section L3 adopts the heating mode of the electromagnetic radiation heater 20 to heat the film 10, the temperature of the film 10 can be rapidly increased to the second process temperature, and the heating efficiency is greatly improved compared with the traditional hot air heating mode. In addition, since it is not necessary to rapidly heat the film 10 by increasing the flow rate of hot air as in the conventional art, the physical deformation of the film 10 can be prevented, and thus the processing quality of the film 10 can be ensured. In addition, since t2 is 0.9t3 to 1.1t3, that is, the heating section L3 can already heat the film 10 to a temperature close to the third process temperature, when the film 10 enters the heat setting section L4, the temperature of the film 10 can be precisely adjusted at the initial part of the heat setting section L4 by hot air heating, and the temperature of the film 10 is controlled at the third process temperature at the rest of the heat setting section L4. Secondly, heating section L3 is located between stretch section L2 and heat setting section L4, can play the effect of keeping apart stretch section L2 and heat setting section L4 for the inside hot-blast of stretch section L2 separates as far as possible with the inside hot-blast of heat setting section L4, avoids mutual interference, has improved stability promptly. Again, the length of the heat setting stage L4 is only associated with the setting process, eliminating the compensating lengthening that interferes with the actual thermal performance factors of the film 10.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

Claims

1. A heat-setting temperature raising unit of a film stretching oven, characterized by comprising:

the film heating device comprises a stretching section, a heating section and a heat setting section, wherein the stretching section, the heating section and the heat setting section are sequentially arranged along the running direction of a film, the stretching section is used for heating the film and controlling the temperature of the film to be at a first process temperature, the heating section is provided with an electromagnetic radiation heater, the electromagnetic radiation heater is used for heating the film to a second process temperature, and the heat setting section is used for heating the film and controlling the film to be at a third process temperature; the first process temperature, the second process temperature and the third process temperature are defined as t1, t2 and t3, respectively; t1< t2, t2 is 0.9t3 to 1.1t 3.

2. The heat-set temperature boost unit of film stretching oven of claim 1, wherein said electromagnetic radiation heater comprises a reflective hood and at least one infrared element disposed on the reflective hood, said infrared element facing said film; the infrared elements project onto the film in a direction perpendicular to the film across opposite sides of the film; the infrared element is an infrared lamp tube and/or an infrared plate.

3. The heat setting temperature raising unit of a film stretching oven as claimed in claim 1, further comprising a track passing through the stretching section, the heating section and the heat setting section in sequence, and a chain clamp assembly running along the track; the chain clamp assembly is used for clamping the side part of the film so as to drive the film to run;

4. The heat setting temperature raising unit of the film stretching oven according to claim 3, wherein the hot air circulating mechanism comprises a wind shielding structure, an air inlet pipe and an air return pipe; the wind shielding structure and the rail are enclosed to form a hot air channel, and the chain clamp assembly is movably arranged in the hot air channel in a penetrating mode; the air inlet pipe and the air return pipe are communicated with the hot air channel, the air inlet pipe is used for introducing hot air into the hot air channel, and the air return pipe is used for recovering the hot air in the hot air channel.

5. The heat-setting temperature raising unit of a film stretching oven according to claim 4, wherein the wind shielding structure includes a first wind shield and a second wind shield; the first wind shield and the second wind shield are arranged at intervals up and down to form a first gap through which the film penetrates, the first wind shield and the second wind shield are arranged at intervals with the chain clamp assembly, and the first wind shield, the second wind shield and the rail are enclosed to form a hot air channel.

6. The heat setting temperature raising unit of a film stretching oven according to claim 5, wherein the air inlet pipe is provided at an end of the hot air passage close to the heat setting section, and the return air pipe is provided at an end of the hot air passage close to the stretching section.

7. The heat setting temperature raising unit of a film stretching oven according to claim 5, wherein the arrangement direction of the air inlet pipe and the running direction of the film form an included angle; the included angle between the air inlet pipe and the running direction of the film is defined as a, and a is less than 90 degrees.

8. The heat-setting temperature raising unit of a film stretching oven according to claim 4, wherein partitions are provided at opposite ends of the heating section in the running direction of the film; the partition plate is provided with a window through which the track, the chain clamp assembly and the film pass, and a wind shielding part is arranged on the wall of the window.

9. The heat-setting temperature raising unit of a film stretching oven according to claim 8, wherein each of the wind shields includes a first wind curtain and a second wind curtain which are disposed at an upper and lower interval on the wall of the window opening, and the first wind curtain and the second wind curtain form a second gap for the film to pass through.

10. A film stretching method characterized by employing the heat-setting temperature raising unit of the film stretching oven as claimed in any one of claims 1 to 9, comprising the steps of: