CN111204036A

CN111204036A - Ventilated membrane stretching device

Info

Publication number: CN111204036A
Application number: CN202010182415.0A
Authority: CN
Inventors: 郑劲松
Original assignee: Fujian Hongke New Material Technology Co Ltd
Current assignee: Fujian Hongke New Material Technology Co Ltd
Priority date: 2020-03-16
Filing date: 2020-03-16
Publication date: 2020-05-29

Abstract

The invention relates to a breathable film stretching device. The breathable film stretching device comprises an oven, an air heater and at least 4 groups of stretching rollers, wherein both ends of the oven are respectively provided with a film inlet and a film outlet, each side surface of the oven is provided with the air heater, and the top of the oven is provided with an air suction port; the air inlet of the hot air blower is communicated with the air suction opening in a fluid manner, and the air outlet is communicated with the hot air opening in a fluid manner; the stretching rollers are arranged on the same horizontal plane in the drying oven in the middle and are evenly spaced, each group of stretching rollers comprises a driving roller and two compression rollers symmetrically arranged on two sides of the driving roller, and the rotating speed of each stretching roller is sequentially increased in the advancing direction of the film. The film is stretched in multiple steps, the stretching rate of each step is small, the film can be fully and uniformly stretched, the air permeability is uniform, the width size is reduced less, and the product yield is improved; and because the film adopts the heated air to heat in the oven uniformly, the surface heating temperature of the film is more uniform compared with the existing heat-conducting oil heating mode, and the stretching is more uniform.

Description

Ventilated membrane stretching device

Technical Field

The invention relates to the field of breathable film production devices, in particular to a breathable film stretching device.

Background

The air permeable film is mainly formed by adding inorganic mineral filler into thermoplastic plastic serving as a carrier through extrusion molding by a casting cold roll forming method and then longitudinally stretching, so that the air permeable film has a unique microporous structure. The micropores with special structures are distributed on the surface of the breathable film in a high density mode, so that the breathable film can not only prevent liquid water from leaking, but also allow gas molecules such as water vapor and the like to pass through. The main application fields of the existing breathable films comprise personal hygiene care products, medical protective products (such as medical mattresses, protective clothing, surgical gowns, surgical sheets, heat application, medical pillowslip and the like), personal protective products in special places, clothing linings, auxiliary materials for medicine packaging, building industries and the like. Breathable films have been widely used in the above fields in europe and the united states, japan, korea, far east, and in the harbor dock area of our country. The existing breathable film stretching device (shown in figure 1) uses 3 groups of hollow stretching rollers 3 to stretch the film 100, the film 100 adopts S-shaped film running, the stretching times are less, and the single stretching proportion is larger and uneven easily occurs; and the roller surface uses the conduction oil that flows through from its inner chamber to heat, gives the film with heat transfer again, uses the back for a long time, has the scale deposit to produce to lead to roller surface temperature uneven, this can lead to the film surface temperature of being heated inhomogeneous, thereby lead to tensile inhomogeneous and the final ventilated membrane finished product the air permeability deviation between the different positions great, be difficult to be applied to the less field of requirement air permeability deviation.

Disclosure of Invention

The invention aims to provide a breathable film stretching device, which aims to solve the problem that the existing stretching device is easy to stretch unevenly.

To achieve the above object, according to an embodiment of the present invention, there is provided a breathable film stretching apparatus, which may include:

the device comprises a drying oven, a film inlet and a film outlet are respectively arranged at two ends of the drying oven, a hot air port is arranged on each side surface, and an air suction port is arranged at the top of the drying oven;

the air inlet of the hot air blower is communicated with the air suction opening in a fluid manner, the air outlet of the hot air blower is communicated with the hot air opening in a fluid manner,

and at least 4 groups of stretching rollers are arranged on the same horizontal plane in the oven in the middle and are uniformly spaced, each group of stretching rollers comprises a driving roller and two compression rollers symmetrically arranged on two sides of the driving roller, a film enters from the film inlet, is stretched by the stretching rollers in each group in sequence and leaves from the film outlet, and the rotating speed of the stretching rollers is sequentially increased progressively along the advancing direction of the film.

Further, the number of stretching rollers does not exceed 8 sets.

Further, the number of the stretching rollers was 5 sets, and the rotation speed ratios therebetween were 1.15, 1.17, and 1.17, respectively.

Further, the driving roller is a stainless steel roller, and the compression roller is a rubber roller; and vice versa.

Further, the diameters of the drive roller and the press roller were 240 mm and 100 mm, respectively.

Further, the distance between two adjacent drive rollers was 400 mm.

Furthermore, the connecting line of the centers of the driving roller and the pressing rollers on the two sides of the driving roller forms an isosceles triangle with a base angle of 30 to 45 degrees.

Furthermore, an air suction cover is arranged in the oven and is positioned above the stretching roller to serve as the air suction opening.

Further, still include preheating roller set and design roller set, preheating roller set arranges before advancing the membrane mouth, design roller set arranges after the play membrane mouth.

Further, preheat the roller set with advance to be equipped with first deflector roll between the membrane mouth, and go out the membrane mouth with be equipped with the second deflector roll between the design roller set, first deflector roll and second deflector roll are arranged into to make the film be in adopt the straight line to walk the membrane in the oven.

Further, the preheating roller set and the shaping roller set respectively comprise three hollow rollers and two compression rollers, the three hollow rollers are arranged in an inverted isosceles triangle, and the two compression rollers are pressed on the hollow rollers on two sides.

Further, the diameter of the hollow roller is larger than that of the press roller.

Furthermore, the first roller, the second roller and the hollow roller are all provided with heat conducting oil which flows through the inner cavities of the first roller, the second roller and the hollow roller.

By adopting the technical scheme, the invention has the beneficial effects that:

1) the film is stretched in multiple steps (more than three steps), the stretching rate of each step is small, the film can be fully and uniformly stretched, the air permeability is uniform, the width size is reduced less, and the product yield is improved;

2) the film is pressed from two sides by two pressing rollers, so that the film cannot slip during stretching, the stretching rate of the product can be improved, and the pores are uniform;

3) because the film is uniformly heated in the oven by adopting the heating air, the heating temperature of the surface of the film is more uniform compared with the existing heat-conducting oil heating mode, and the stretching is more uniform.

Drawings

FIG. 1 is a schematic view of a conventional stretching apparatus for a breathable film;

FIG. 2 is a schematic front view of a breathable film stretching apparatus according to an embodiment of the present invention.

Detailed Description

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings in order to more clearly understand the objects, features and advantages of the present invention. It should be understood that the embodiments shown in the drawings are not intended to limit the scope of the present invention, but are merely intended to illustrate the spirit of the technical solution of the present invention.

In the following description, for the purposes of illustrating various disclosed embodiments, certain specific details are set forth in order to provide a thorough understanding of the various disclosed embodiments. One skilled in the relevant art will recognize, however, that the embodiments may be practiced without one or more of the specific details. In other instances, well-known devices, structures and techniques associated with this application may not be shown or described in detail to avoid unnecessarily obscuring the description of the embodiments.

Throughout the specification and claims, the word "comprise" and variations thereof, such as "comprises" and "comprising," are to be understood as an open, inclusive meaning, i.e., as being interpreted to mean "including, but not limited to," unless the context requires otherwise.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

As used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. It should be noted that the term "or" is generally employed in its sense including "and/or" unless the context clearly dictates otherwise.

In the following description, for the purposes of clearly illustrating the structure and operation of the present invention, directional terms will be used, but terms such as "front", "rear", "left", "right", "outer", "inner", "outer", "inward", "upper", "lower", etc. should be construed as words of convenience and should not be construed as limiting terms.

It is to be noted that in the claims and the description of the present application, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.

As shown in fig. 2, the breathable film stretching apparatus according to an embodiment of the present invention may include an oven 1, a hot air blower 2, and at least 4 sets of stretching rollers 3. The number of stretching rollers 3 does not normally exceed 8 sets. The oven 1 has a rectangular parallelepiped shape, and is substantially closed except for a film inlet 11 and a film outlet 12 provided at both ends to prevent heat loss. Preferably, the outer surface of oven 1 is coated with a heat insulating layer to reduce heat loss and save energy consumption. Each side of the oven 1 is provided with a hot air port, and the top of the oven is provided with an air suction port. In the embodiment shown, the air suction opening takes the form of an air suction hood 4. An air suction hood 4 is arranged in the oven 1 above the stretching roller 3. The air inlet of the air heater 2 is communicated with the air suction opening in a fluid mode, and the air outlet is communicated with the hot air opening in a fluid mode. That is, oven 1 is internally circulated by hot air blower 2, which on the one hand ensures that the temperature inside oven 1 is substantially at the desired temperature (e.g., 80 ℃), and on the other hand greatly improves energy efficiency. The sets of draw rolls 3 are centrally arranged on the same horizontal plane within the oven 1 and are evenly spaced apart. The film enters the oven 1 from the film inlet 11, is stretched by the stretching rollers 3 in sequence, and leaves the oven 1 from the film outlet 12, so that the stretching process is completed. Because the film adopts the heating air to heat in oven 1 uniformly, make the film surface temperature of being heated more even for current conduction oil heating mode to make the drawing more even. The rotation speed of the stretching roller 3 is sequentially increased in the film advancing direction. The increasing proportion of the rotating speed of the two adjacent groups of stretching rollers 3 can be the same or different. In one specific embodiment, the number of draw rolls is 5 sets with a ratio of 1.15, 1.17 and 1.17 between the speeds. In this case, the film is capable of achieving a stretch of 1.84(1.15 × 1.17 ═ 1.84). Because multi-step (more than three steps) stretching is adopted, for the same stretching multiple, the stretching rate of each step is smaller, the full and uniform stretching of the film can be realized, the air permeability is uniform, the width size of the product is reduced less, and the product yield is improved.

Each set of stretching rollers 3 comprises a driving roller 31 and two pressing rollers 32 symmetrically arranged on both sides thereof. That is, the line connecting the centers of the driving roll 31 and the two pressing rolls 32 forms an isosceles triangle. The base angle of the isosceles triangle is typically between 30 and 45 degrees. Wherein, the driving roller 31 is a stainless steel roller, and the pressing roller 32 is a rubber roller; and vice versa. This avoids a rigid contact between the drive roll and the pressure roll. The drive roll 31 and the press roll 32 may have the same or different diameters. In the embodiment shown, the diameter of the drive roll 31 is larger than the diameter of the press roll 32. In a particular embodiment, the diameters of the drive roller 31 and the pressure roller 32 are 240 mm and 100 mm, respectively; the distance between two adjacent drive rollers 31 is 400 mm; the base angle of an isosceles triangle formed by connecting the centers of the driving roller 31 and the two pressing rollers 32 is 36 degrees. Two press rolls 32 are used to press the film 100 from both sides, so that the film 100 does not slip when stretched, the stretching ratio of the product can be improved, and the pores are uniform, i.e., the air permeability is uniform.

In the illustrated embodiment, the breathable film stretching device of the present invention may further comprise a preheating roller set 5 and a shaping roller set 6, wherein the preheating roller set 5 is arranged before the film inlet 11 of the oven 1 and is used for preheating the film, for example, to about 50 ℃. The preheating roller group 5 includes three hollow rollers 51 and two press rollers 52, wherein the three hollow rollers 51 are arranged in an inverted isosceles triangle, and the two press rollers 52 press against the hollow rollers 51 on both sides. The hollow roller 51 is filled with heat conducting oil, i.e., heated by the heat conducting oil. The diameter of the hollow roller 51 is generally larger than the diameter of the press roller 52. The shaping roller set 6 is arranged behind the film outlet 12 of the oven 1. The shaping roller set 6 has the same structure as the preheating roller set 5 and is used for shaping the stretched film. The film adopts S-shaped film-moving to pass through the preheating roller set 5 and the shaping roller set 6.

Preferably, a first guide roller 7 is arranged between the preheating roller group 5 and the film inlet 11, and a second guide roller 8 is arranged between the film outlet 12 and the shaping roller group 6. Specifically, the first guide roller 7 and the second guide roller 8 are respectively arranged outside the oven 1 and close to the film inlet 11 and the film outlet 12. The first guide roll 7 and the second guide roll 8 are arranged with the stretching roll 3 such that the film between them is substantially in the same horizontal plane to ensure that the film runs substantially straight inside the oven 1. In the embodiment shown, a third guide roller 9 is also provided between the second guide roller 8 and the shaping roller set 6 in order to avoid the oven 1, the third guide roller 9 being located to the left below the second guide roller 8 and to the left above the shaping roller set 6. The first guide roller 7 and the second guide roller 8 are also heated by heat conducting oil.

The advantageous effects of the breathable film stretching device of the present invention will be described below by way of comparative experiments. The experimental materials are breathable films stretched by adopting a traditional breathable film stretching device and the breathable film stretching device. The width of the air permeable film was about 1.6 m, and samples were taken every 300 mm for a total of 5 groups of samples, which were designated by reference numerals 1 to 5, respectively.

Experiment one

Measuring the grammage (unit: g/m)²) The results are shown in Table 1.

TABLE 1 grammage comparison

As can be seen from Table 1, the average grammage of the breathable film obtained by using the conventional breathable film stretching device is 44.34, the maximum grammage is 45.2, and the minimum grammage is 43.6, which is different by 1.6, while the average grammage of the breathable film obtained by using the breathable film stretching device of the present invention is 44.16, the maximum grammage is 44.6, and the minimum grammage is 43.7, which is different by 1.0, which shows that the uniformity of the breathable film obtained by using the breathable film stretching device of the present invention is better.

Experiment two

The air passage time (unit: second) was measured using a blood pressure meter, and the results of the experiment are shown in Table 2.

TABLE 2 comparison of ventilation transit times

As can be seen from Table 2, the film obtained by using the film stretching apparatus of the present invention has better uniformity.

Experiment three

Air permeability (unit: sec) was measured using a jordan air permeameter, which measures the time for every cubic meter of air to pass through 1 square meter of air permeable membrane, and the results of the experiment are shown in table 3.

TABLE 3 air permeability contrast

As can be seen from Table 3, the breathable film obtained by using the conventional breathable film stretching device has nonuniform air permeability: the maximum value reached 20325 and the minimum value was only 13550, which are different from each other by 6775, whereas the difference between the maximum value 17223 and the minimum value 16573 of the breathable film obtained by using the breathable film stretching device of the present invention was only 650, which shows that the uniformity of the breathable film obtained by using the breathable film of the present invention is better.

Experiment four

Measurement 24 using a constant temperature and humidity chamberMoisture permeability in hours (unit: g/m)²) The results are shown in Table 4.

TABLE 3 comparison of moisture vapor transmission

As can be seen from Table 4, the moisture permeability of the breathable film obtained by using the conventional breathable film stretching device is not uniform: the maximum value is 1231, the minimum value is 529, the difference between the maximum value and the minimum value is 702, and the difference between the maximum value 608 and the minimum value 572 of the breathable film obtained by the breathable film stretching device is only 36, so that the uniformity of the breathable film obtained by the breathable film stretching device is better.

While the preferred embodiments of the present invention have been illustrated and described in detail, it should be understood that various changes and modifications of the invention can be effected therein by those skilled in the art after reading the above teachings of the invention. Such equivalents are intended to fall within the scope of the claims appended hereto.

Claims

1. A vented membrane stretching apparatus, comprising:

and at least 4 groups of stretching rollers are arranged on the same horizontal plane in the oven in the middle and are uniformly spaced, each group of stretching rollers comprises a driving roller and two compression rollers symmetrically arranged on two sides of the driving roller, a film enters from the film inlet, is stretched by the stretching rollers in sequence and leaves from the film outlet, and the rotating speed of the stretching rollers is sequentially increased in sequence along the film advancing direction.

2. The breathable film stretching apparatus of claim 1, wherein the number of stretching rollers does not exceed 8 sets.

3. The breathable film stretching apparatus according to claim 2, wherein the number of the stretching rollers is 5 sets, and the rotation speed ratios therebetween are 1.15, 1.17 and 1.17, respectively.

4. The breathable film stretching apparatus of claim 1, wherein the drive roll is a steel roll and the pressure roll is a rubber roll; and vice versa.

5. The breathable film stretching apparatus of claim 3, wherein the drive roll and the pressure roll have diameters of 240 mm and 100 mm, respectively.

6. The breathable film stretching apparatus of claim 4, wherein the distance between two adjacent drive rolls is 400 mm.

7. The breathable film stretching apparatus of claim 4, wherein the driving roll forms an isosceles triangle having a base angle of 30 to 45 degrees with respect to a line connecting centers of the pressing rolls on both sides of the driving roll.

8. The breathable film stretching apparatus of claim 1, wherein an air suction hood is disposed inside the oven and above the stretching roller as the air suction opening.

9. The breathable film stretching apparatus of claim 1, further comprising a set of pre-heating rollers disposed before the film inlet and a set of sizing rollers disposed after the film outlet.

10. The breathable film stretching device of claim 9, wherein a first guide roller is disposed between the preheating roller set and the film inlet, and a second guide roller is disposed between the film outlet and the sizing roller set, and the first guide roller and the second guide roller are arranged such that the film is linearly drawn in the oven.