A waterproof breathable membrane stretching device

Abstract

The present invention relates to a waterproof breathable film stretching device, comprising an oven, a hot air blower and at least 4 groups of solid stretching rollers, wherein the two ends of the oven are respectively provided with a film inlet and a film outlet, and each side thereof is provided with a hot air outlet, and the top is provided with an air suction port; the air inlet of the hot air blower is fluidly connected with the air suction port, and the air outlet is fluidly connected with the hot air outlet; the stretching rollers are centrally arranged on the same horizontal plane in the oven and are evenly spaced apart, and the rotation speed of the stretching rollers increases successively along the film travel direction. The film is stretched by multiple steps, and the stretching rate of each step is small, which can not only realize full and uniform stretching of the film, uniform air permeability, but also less reduction in width, thereby improving product output; and because the film is evenly heated in the oven by heated air, the heating temperature of the film surface is more uniform compared with the existing heat transfer oil heating method, thereby making the stretching more uniform.

Description

Technical Field

[0001] The invention relates to the field of waterproof breathable membrane production devices, in particular to a waterproof breathable membrane stretching device. Background Art

[0002] The waterproof breathable membrane is mainly based on thermoplastic plastic as a carrier, and after adding inorganic mineral fillers, it is extruded by the cast cold roll molding method, and then longitudinally stretched to give it a unique microporous structure. These special structure micropores distributed at a high density on the surface of the waterproof breathable membrane enable the waterproof breathable membrane to not only block the leakage of liquid water, but also allow gas molecules such as water vapor to pass through. At present, the main application areas of waterproof breathable membranes include personal hygiene care products, medical protective products (such as medical mattresses, protective clothing, surgical gowns, surgical sheets, hot compresses, medical pillowcases, etc.), personal protective equipment for special places, clothing linings, auxiliary materials for pharmaceutical packaging, and the construction industry. In Europe, America, Japan, South Korea, the Far East, and Hong Kong and Taiwan in my country, waterproof breathable membranes have been widely used in the above-mentioned fields. Existing waterproof breathable membrane stretching devices (such as Figure 1 As shown in the figure, three groups of hollow stretching rollers 3 are used to stretch the film 100. The film 100 adopts an S-shaped film path and has a small number of stretching times, resulting in a large single stretching ratio and prone to unevenness. The roller surface is heated by heat-conducting oil flowing through its inner cavity, and the heat is then transferred to the film. After long-term use, scaling will occur, resulting in uneven roller surface temperature, which will cause uneven heating temperature on the film surface, resulting in uneven stretching and large air permeability deviations between different parts of the final waterproof and breathable membrane product, making it difficult to apply to fields that require a small air permeability deviation. Summary of the invention

[0003] The purpose of the present invention is to provide a waterproof breathable membrane stretching device to solve the problem that the existing stretching device is prone to uneven stretching.

[0004] To achieve the above object, according to an embodiment of the present invention, a waterproof breathable membrane stretching device is provided, which may include:

[0005] An oven, wherein the two ends of the oven are respectively provided with a film inlet and a film outlet, hot air outlets are provided on each side, and an air suction outlet is provided on the top;

[0006] A hot air blower, wherein the air inlet of the hot air blower is fluidly connected to the air inlet, and the air outlet is fluidly connected to the hot air outlet,

[0007] and at least 4 groups of solid stretching rollers, which are centrally arranged on the same horizontal plane in the oven and evenly spaced apart. The film enters from the film inlet in a straight line, is stretched by each group of stretching rollers in sequence, and leaves from the film outlet. The rotation speed of the stretching rollers increases successively along the film travel direction.

[0008] Further, the number of the stretching rollers is 5 groups, and the rotation speed ratios therebetween are 1.15, 1.17, 1.17 and 1.17 respectively.

[0009] Furthermore, each stretching roller pair includes a driving roller and a pressure roller, wherein the driving roller is a stainless steel roller and the pressure roller is a rubber roller.

[0010] Furthermore, the diameters of the driving roller and the pressure roller are both 100 mm.

[0011] Further, the distance between adjacent stretching roller pairs is 20 mm.

[0012] Furthermore, an air suction hood is provided in the oven, and the air suction hood is located above the stretching roller and serves as the air suction port.

[0013] Furthermore, it also includes a preheating roller group and a shaping roller group, wherein the preheating roller group is arranged before the film inlet, and the shaping roller group is arranged after the film outlet.

[0014] Furthermore, a first guide roller is provided between the preheating roller group and the film inlet, and a second guide roller is provided between the film outlet and the shaping roller group.

[0015] Furthermore, the preheating roller group and the shaping roller group each include three hollow rollers and two pressing rollers, the three hollow rollers are arranged in an inverted isosceles triangle, and the two pressing rollers are pressed against the hollow rollers on both sides.

[0016] Furthermore, the diameter of the hollow roller is larger than the diameter of the pressing roller.

[0017] Furthermore, the first roller, the second roller and the hollow roller all have heat transfer oil flowing through their inner cavities.

[0018] The present invention adopts the above technical scheme, which has the beneficial effects of: the film is stretched by multiple steps (more than three steps), and the stretching rate of each step is small, which not only can achieve sufficient and uniform stretching of the film and uniform air permeability, but also less reduction in width, thereby improving product output; and because the film is evenly heated in the oven by heated air, the heating temperature of the film surface is more uniform compared to the existing thermal oil heating method, thereby making the stretching more uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of an existing stretching device;

[0020] Figure 2 is a schematic diagram of a stretching device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0021] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings so that the purpose, features and advantages of the present invention can be more clearly understood. It should be understood that the embodiments shown in the accompanying drawings are not intended to limit the scope of the present invention, but are only intended to illustrate the essential spirit of the technical solution of the present invention.

[0022] In the following description, certain specific details are set forth for the purpose of illustrating various disclosed embodiments to provide a thorough understanding of the various disclosed embodiments. However, those skilled in the relevant art will recognize that the embodiments may be practiced without one or more of these specific details. In other cases, well-known devices, structures, and techniques associated with the present application may not be shown or described in detail to avoid unnecessarily obscuring the description of the embodiments.

[0023] Unless the context requires otherwise, throughout the specification and claims, the word "comprise" and variations such as "include" and "have" should be construed in an open, inclusive sense, ie, should be interpreted as "including, but not limited to."

[0024] References throughout the specification to "one embodiment" or "an embodiment" indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of "in one embodiment" or "in an embodiment" in various places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any manner in one or more embodiments.

[0025] 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.

[0026] In the following description, in order to clearly show the structure and working mode of the present invention, many directional words will be used for description, but the words "front", "back", "left", "right", "outside", "inside", "outward", "inward", "up", "down", etc. should be understood as convenient terms and should not be understood as restrictive terms.

[0027] It should be noted that in the claims and description of the present application, relational terms such as first and second, etc. are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0028] like Figure 2As shown, the waterproof breathable membrane stretching device according to an embodiment of the present invention may include an oven 1, a hot air blower 2 and at least 4 groups (5 groups are shown) of solid stretching rollers 3. The oven 1 is in the shape of a rectangular parallelepiped, and is basically closed except for the film inlet 11 and the film outlet 12 arranged at both ends to prevent heat loss. Preferably, the outer surface of the oven 1 is covered with an insulation layer to reduce heat loss and save energy consumption. Hot air outlets are provided on each side of the oven 1, and an air suction port is provided on the top. In the embodiment shown, the air suction port is in the form of an air suction hood 4. The air suction hood 4 is arranged in the oven 1 and is located above the stretching roller 3. The air inlet of the hot air blower 2 is fluidly connected to the air suction port, and the air outlet is fluidly connected to the hot air port. That is, the oven 1 realizes internal circulation through the hot air blower 2, which can ensure that the temperature in the oven 1 is basically at the required temperature (for example, 80°C) on the one hand, and greatly improves energy efficiency on the other hand. Each group of stretching rollers 3 is centrally arranged on the same horizontal plane in the oven 1 and evenly spaced. The film is stretched in a straight line, enters the oven 1 from the film inlet 11, is stretched by each group of stretching rollers 3 in sequence, and leaves the oven 1 from the film outlet 12 to complete the stretching process. Since the film is evenly heated in the oven 1 by heated air, the surface temperature of the film is more uniform compared to the existing thermal oil heating method, so that the stretching is more uniform. The rotation speed of the stretching roller 3 increases successively along the direction of film travel. In a specific embodiment, the number of stretching rollers is 5 groups, and the speed ratios between them are 1.15, 1.17, 1.17 and 1.17 respectively. In this case, the film can achieve 1.84 (1.15*1.17*1.17*1.17=1.84) times of stretching. Due to the use of multi-step (more than three steps) stretching, for the same stretching multiple, the stretching rate of each step is small, which can not only achieve full and uniform stretching of the film, uniform air permeability, but also less reduction in the width size of the product, thereby increasing product output.

[0029] Each group of stretching rollers 3 includes a driving roller 31 and a pressure roller 32, wherein the driving roller 31 is a stainless steel roller and the pressure roller 32 is a rubber roller. The diameters of the driving roller 31 and the pressure roller 32 may be the same or different. In the illustrated embodiment, the diameters of the driving roller 31 and the pressure roller 32 are the same. Preferably, the diameters thereof are 80-150 mm. Compared with the stretching roller 3 of the prior art, the diameter thereof is reduced, thereby narrowing the stretching gap to ensure that the stretching efficiency is increased during a single stretching. In a specific embodiment, the diameters of the driving roller 31 and the pressure roller 32 are both 100 mm, and the distance between two adjacent groups of stretching rollers 3 is 20 mm.

[0030] In the illustrated embodiment, the stretching device of the present invention may further include a preheating roller group 5 and a shaping roller group 6, wherein the preheating roller group 5 is arranged before the film inlet 11 of the oven 1, and is used to preheat the film, for example, to about 50°C. The preheating roller group 5 includes three hollow rollers 51 and two pressing rollers 52, wherein the three hollow rollers 51 are arranged in an inverted isosceles triangle, and the two pressing rollers 52 are pressed against the hollow rollers 51 on both sides. Heat transfer oil is passed through the hollow rollers 51, that is, the heat transfer oil is used for heating. The diameter of the hollow roller 51 is usually larger than the diameter of the pressing roller 52. The shaping roller group 6 is arranged after the film outlet 12 of the oven 1. The structure of the shaping roller group 6 is the same as that of the preheating roller group 5, and is used to shape the stretched film. The film passes through the preheating roller group 5 and the shaping roller group 6 in an S-shaped film path.

[0031] Preferably, a first guide roller 7 is provided between the preheating roller group 5 and the film inlet 11, and a second guide roller 8 is provided 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 provided outside the oven 1 near the film inlet 11 and the film outlet 12. The first guide roller 7 and the second guide roller 8 are arranged with the stretching roller 3 so that the film therebetween is on the same horizontal plane. Preferably, in the illustrated embodiment, a third guide roller 9 is further provided between the second guide roller 8 and the shaping roller group 6. The third guide roller 9 is lower than the second guide roller 9, and the first guide roller 7 and the second guide roller 8 are also heated by thermal oil.

[0032] The following comparative experiments are used to illustrate the beneficial effects of the new stretching device. The experimental materials are respectively waterproof breathable membranes stretched by the conventional stretching device and the new stretching device of the present invention. The width of the waterproof breathable membrane is about 1.6 meters, and a sample is taken every 300 mm. There are 5 groups of samples in total, which are represented by 1-5 respectively.

[0033] Experiment 1

[0034] Measure weight (unit: g / m 2 ), the experimental results are shown in Table 1.

[0035] Table 1 Weight comparison

[0036]

[0037] It can be seen from Table 1 that the waterproof and breathable membrane obtained by using the new stretching device has better uniformity.

[0038] Experiment 2

[0039] The air passage time (unit: seconds) was measured using a sphygmomanometer. The experimental results are shown in Table 2.

[0040] Table 2 Comparison of ventilation time

[0041]

[0042]

[0043] It can be seen from Table 2 that the waterproof and breathable membrane obtained by using the new stretching device has better uniformity.

[0044] Experiment 3

[0045] The air permeability (unit: second) was measured using a Wang Yan-type air permeability meter. The data measured by the Wang Yan-type air permeability meter is the time it takes for one cubic meter of air to pass through one square meter of breathable membrane. The experimental results are shown in Table 3.

[0046] Table 3 Comparison of air permeability

[0047]

[0048] It can be seen from Table 3 that the air permeability of the breathable membrane obtained by the traditional stretching device is uneven: the maximum value reaches 20325, while the minimum value is only 13550, with a difference of 6775. The maximum value 17782 and the minimum value 16640 of the breathable membrane obtained by the new stretching device only differ by 1142. It can be seen that the waterproof breathable membrane obtained by the new stretching device has better uniformity.

[0049] Experiment 4

[0050] The moisture permeability (unit: g / m 2 ), the experimental results are shown in Table 4.

[0051] Table 3 Comparison of moisture permeability

[0052]

[0053] It can be seen from Table 4 that the moisture permeability of the breathable membrane obtained by the traditional stretching device is uneven: the maximum value reaches 1231, while the minimum value is only 529, with a difference of 702. The maximum value 607 and the minimum value 560 of the breathable membrane obtained by the new stretching device only differ by 47. It can be seen that the waterproof breathable membrane obtained by the new stretching device has better uniformity.

[0054] The preferred embodiments of the present invention have been described in detail above, but it should be understood that after reading the above teachings of the present invention, those skilled in the art may make various changes or modifications to the present invention. These equivalent forms also fall within the scope defined by the appended claims of this application.

Claims

1. A waterproof breathable membrane stretching device, characterized in that: include: An oven, wherein the two ends of the oven are respectively provided with a film inlet and a film outlet, hot air outlets are provided on each side, and an air suction outlet is provided on the top; A hot air blower, wherein the air inlet of the hot air blower is fluidly connected to the air inlet, and the air outlet is fluidly connected to the hot air outlet, and at least 4 groups of solid stretching rollers, which are centrally arranged on the same horizontal plane in the oven and are evenly spaced apart, and the film is fed in a straight line from the film inlet, stretched by each group of the stretching rollers in sequence, and leaves from the film outlet, and the rotation speed of the stretching rollers increases in sequence along the film travel direction; The number of the stretching rollers is 5 groups, and the speed ratios therebetween are 1.15, 1.17, 1.17 and 1.17 respectively; Each set of stretching rollers includes a driving roller and a pressing roller. The diameters of the driving roller and the pressing roller are both 100 mm. The distance between two adjacent sets of stretching rollers is 20 mm.

2. The waterproof breathable membrane stretching device according to claim 1, characterized in that: The active roller is a stainless steel roller, and the pressure roller is a rubber roller.

3. The waterproof breathable membrane stretching device according to claim 1, characterized in that: An air suction hood is provided in the oven, and the air suction hood is located above the stretching roller and serves as the air suction port.

4. The waterproof breathable membrane stretching device according to claim 1, characterized in that: It also includes a preheating roller group and a shaping roller group, wherein the preheating roller group is arranged before the film inlet, and the shaping roller group is arranged after the film outlet.

5. The waterproof breathable membrane stretching device according to claim 4, characterized in that: A first guide roller is provided between the preheating roller group and the film inlet, and a second guide roller is provided between the film outlet and the shaping roller group.

6. The waterproof breathable membrane stretching device according to claim 5, characterized in that: The preheating roller group and the shaping roller group both include three hollow rollers and two pressing rollers. The three hollow rollers are arranged in an inverted isosceles triangle, and the two pressing rollers are pressed against the hollow rollers on both sides.

7. The waterproof breathable membrane stretching device according to claim 6, characterized in that: The first guide roller, the second guide roller and the hollow roller all have heat transfer oil flowing through their inner cavities.

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